2018, 電子情報通信学会通信ソサイエティ, チュートリアル（和文）論文賞　　　　　　　　　　　　　　　

Jun. 2016, 北海道総合通信局, 第66回「電波の日」北海道総合通信局長表彰　　　　　　　　　　　　　　　
大鐘武雄

2011, 電子情報通信学会通信ソサイエティ, マガジン論文賞　　　　　　　　　　　　　　　
大鐘武雄

2008, 電気通信普及財団, テレコムシステム技術賞　　　　　　　　　　　　　　　
大鐘武雄

2007, 電子情報通信学会, 論文賞　　　　　　　　　　　　　　　
大鐘武雄

1993, IEEE AP-S Tokyo Chapter, Young Engineer Award　　　　　　　　　　　　　　　
大鐘武雄

Characterization of Sub-THz-Band MIMO Spatial Multiplexing in Indoor Environments
Naoki Hamada, Toshihiko Nishimura, Yasutaka Ogawa, Satoshi Suyama, Takeo Ohgane
IEICE Transactions on Communications, E109-B, 2, 199, 212, Institute of Electrical and Electronics Engineers (IEEE), Feb. 2026
Scientific journal

A Measurement of Packet Delivery Rate and Signal Strength in LoRa Communication in Urban and Suburban Areas of Sapporo　　　　　　　　　　　　　　　
Yuito Ishisaki, Kyotaro Kunii, Hiroshi Tsutsui, Takeo Ohgane
Proceedings of IEEE R10 Humanitarian Technology Conference (IEEE R10 HTC), Sep. 2025, [Peer-reviewed]
English, International conference proceedings

Study on Loose Beamforming Applying Channel Simplification　　　　　　　　　　　　　　　
Ryoma Yabe, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
Proceedings IEEE VTS APWCS 2025, Aug. 2025, [Peer-reviewed]
International conference proceedings

Comparative Evaluation of CNN, VGG16, Conformer, and YAMNet Models for Skateboard Riding Sound Detection　　　　　　　　　　　　　　　
Haruka Sakaki, Kenshiro Tanaka, Chenyu Zhao, Hiroshi Tsutsui, Takeo Ohgane
Proceedings of International Symposium on Multimedia and Communication Technology (ISMAC), Aug. 2025, [Peer-reviewed]
International conference proceedings

Design and Implementation of a Real-Time Acoustic Feature Visualization System on Raspberry Pi Platform Utilizing Fixed-Point FPGA-Based Mel Spectrum Extraction　　　　　　　　　　　　　　　
Chenyu Zhao, Hiroshi Tsutsui, Takeo Ohgane
Proceedings of International Symposium on Multimedia and Communication Technology (ISMAC), Aug. 2025, [Peer-reviewed]
International conference proceedings

Strategies for DOA-DNN Estimation Accuracy Improvement at Low and High SNRs.
Daniel Akira Ando, Toshihiko Nishimura, Takanori Sato, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
IEICE Trans. Commun., 108, 1, 94, 108, Institute of Electrical and Electronics Engineers (IEEE), Jan. 2025, [Peer-reviewed]
Scientific journal

Evaluation of Computational Cost and Result Accuracy in Design and Efficient Implementation of Log-Mel Spectrogram and MFCC Feature Extraction Using Fixed-Point Arithmetic on FPGA.
Chenyu Zhao, Naoya Yamamura, Hiroshi Tsutsui, Takeo Ohgane
ISPACS, 1, 5, Dec. 2024, [Peer-reviewed]
International conference proceedings

Performance Evaluation of Loose Beamforming Using Direct-Binary Search in Massive MIMO Systems.
Yuta Hayashi, Toshihiko Nishimura, Takanori Sato, Yasutaka Ogawa, Takeo Ohgane
International Conference on Computing, Networking and Communications(ICNC), 323, 328, IEEE, Feb. 2024, [Peer-reviewed]
International conference proceedings

Hamiltonian Monte Carlo-Based Near-Optimal MIMO Signal Detection.
Junichiro Hagiwara, Toshihiko Nishimura, Takanori Sato, Yasutaka Ogawa, Takeo Ohgane
CoRR, abs/2412.02391, 2024
Scientific journal

Near-Optimal Stochastic MIMO Signal Detection with a Mixture of T-Distributions Prior.
Junichiro Hagiwara, Kazushi Matsumura, Hiroki Asumi, Yukiko Kasuga, Toshihiko Nishimura, Takanori Sato, Yasutaka Ogawa, Takeo Ohgane
IEEE Global Communications Conference(GLOBECOM), 6627, 6633, IEEE, Dec. 2023, [Peer-reviewed]
International conference proceedings

Deep Neural Networks Based End-to-End DOA Estimation System
Daniel Akira ANDO, Yuya KASE, Toshihiko NISHIMURA, Takanori SATO, Takeo OHGANE, Yasutaka OGAWA, Junichiro HAGIWARA
IEICE Transactions on Communications, E106.B, 12, 1350, 1362, Institute of Electronics, Information and Communications Engineers (IEICE), 01 Dec. 2023, [Peer-reviewed]
Scientific journal

Considerations on IRS Control Based on Beamforming for Sub-Terahertz-Band Communications　　　　　　　　　　　　　　　
S. Tadokoro, T. Nishimura, T. Sato, Y. Ogawa, T. Ohgane
Proceedings of International Conference on Emerging Technologies for Communications (ICETC) 2023, Nov. 2023, [Peer-reviewed]
International conference proceedings

Study on Subarray Beam Allocation for Sub-Terahertz-Band MIMO Spatial Multiplexing in Indoor Office Environments　　　　　　　　　　　　　　　
N. Hamada, T. Nishimura, T. Sato, Y. Ogawa, T. Ohgane
Proceedings of International Conference on Emerging Technologies for Communications (ICETC) 2023, Nov. 2023
International conference proceedings

Performance Analysis of DNN-PCA for DOA Estimation with Three Radio Wave Sources
Daniel Akira Ando, Toshihiko Nishimura, Takanori Sato, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2023 22nd International Symposium on Communications and Information Technologies (ISCIT), IEEE, 16 Oct. 2023, [Peer-reviewed]
International conference proceedings

Power Consumption and Prototype Evaluation of IoT Devices for Environmental Monitoring Systems.
Kota Hirai, Hiroshi Tsutsui, Ying He, Takeo Ohgane
ISCIT, 231, 234, Oct. 2023, [Peer-reviewed], ［Internationally co-authored］
International conference proceedings

Smart Radio Environments with Intelligent Reflecting Surfaces for 6G Sub-Terahertz-Band Communications
Yasutaka OGAWA, Shuto TADOKORO, Satoshi SUYAMA, Masashi IWABUCHI, Toshihiko NISHIMURA, Takanori SATO, Junichiro HAGIWARA, Takeo OHGANE
IEICE Transactions on Communications, E106.B, 9, 735, 747, Institute of Electronics, Information and Communications Engineers (IEICE), 01 Sep. 2023, [Peer-reviewed], [Invited]
Scientific journal

Sub-Terahertz MIMO Spatial Multiplexing in Indoor Propagation Environments
OGAWA Yasutaka, UTSUNO Taichi, NISHIMURA Toshihiko, OHGANE Takeo, SATO Takanori
IEICE Transactions on Communications, E105.B, 10, 1130, 1138, The Institute of Electronics, Information and Communication Engineers, 01 Oct. 2022, [Peer-reviewed], [Invited]
English, Scientific journal, A sub-Terahertz band is envisioned to play a great role in 6G to achieve extreme high data-rate communication. In addition to very wide band transmission, we need spatial multiplexing using a hybrid MIMO system. A recently presented paper, however, reveals that the number of observed multipath components in a sub-Terahertz band is very few in indoor environments. A channel with few multipath components is called sparse. The number of layers (streams), i.e. multiplexing gain in a MIMO system does not exceed the number of multipaths. The sparsity may restrict the spatial multiplexing gain of sub-Terahertz systems, and the poor multiplexing gain may limit the data rate of communication systems. This paper describes fundamental considerations on sub-Terahertz MIMO spatial multiplexing in indoor environments. We examined how we should steer analog beams to multipath components to achieve higher channel capacity. Furthermore, for different beam allocation schemes, we investigated eigenvalue distributions of a channel Gram matrix, power allocation to each layer, and correlations between analog beams. Through simulation results, we have revealed that the analog beams should be steered to all the multipath components to lower correlations and to achieve higher channel capacity.

Experimental Evaluation and Field Tests of LoRa Energy Consumption Optimization Approach Using Software-Defined Radio
Kyotaro Kunii, Takuya Yasugi, Hiroshi Tsutsui, Takeo Ohgane
Proceedings of International Workshop on Smart Info-Media Systems in Asia (SISA) 2022, Sep. 2022, [Peer-reviewed]
International conference proceedings

Parameter-Learned AMP for MIMO Signal Detection
Mari Miyoshi, Wakaba Tsujimoto, Toshihiko Nishimura, Takanori Sato, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2022 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), 99, 103, IEEE, 24 Aug. 2022, [Peer-reviewed]
International conference proceedings

Accuracy Improvement in DOA Estimation with Deep Learning
Yuya KASE, Toshihiko NISHIMURA, Takeo OHGANE, Yasutaka OGAWA, Takanori SATO, Yoshihisa KISHIYAMA
IEICE Transactions on Communications, E105-B, 5, 588, 599, The Institute of Electronics, Information and Communication Engineers, May 2022, [Peer-reviewed]
English, Scientific journal, Direction of arrival (DOA) estimation of wireless signals is demanded in many applications. In addition to classical methods such as MUSIC and ESPRIT, non-linear algorithms such as compressed sensing have become common subjects of study recently. Deep learning or machine learning is also known as a non-linear algorithm and has been applied in various fields. Generally, DOA estimation using deep learning is classified as on-grid estimation. A major problem of on-grid estimation is that the accuracy may be degraded when the DOA is near the boundary. To reduce such estimation errors, we propose a method of combining two DNNs whose grids are offset by one half of the grid size. Simulation results show that our proposal outperforms MUSIC which is a typical off-grid estimation method. Furthermore, it is shown that the DNN specially trained for a close DOA case achieves very high accuracy for that case compared with MUSIC.

A Proposal of an End-to-End DoA Estimation System Aided by Deep Learning
Daniel Akira Ando, Toshihiko Nishimura, Takanori Sato, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
International Symposium on Wireless Personal Multimedia Communications, WPMC, 2022-October, 98, 103, 2022, [Peer-reviewed]
International conference proceedings

A Novel MIMO Signal Detection Method Using Hamiltonian Monte Carlo Approach
Kazushi Matsumura, Junichiro Hagiwara, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Takanori Sato
2021 24th International Symposium on Wireless Personal Multimedia Communications (WPMC), IEEE, 14 Dec. 2021, [Peer-reviewed]
International conference proceedings

An Evaluation of 5G LDPC Decoder Using Min-Sum Irregular LDPC Decoder Design Framework Considering Its QC-LDPC Structure　　　　　　　　　　　　　　　
Jimpu Suzuki, Hiroshi Tsutsui, Takeo Ohgane
Proceedings of International Workshop on Smart Info-Media Systems in Asia (SISA) 2021, Sep. 2021, [Peer-reviewed]
International conference proceedings

Downlink Channel Estimation Based on Multipath Separation in an FDD MIMO System.
Shiori Tosaka, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara, Takanori Sato
Proc. IEEE APWCS 2021, 1, 5, IEEE, Aug. 2021, [Peer-reviewed]
International conference proceedings

光の領域と融合する無線通信　　　　　　　　　　　　　　　
西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄
電子情報通信学会誌, 104, 5, May 2021, [Peer-reviewed]
Scientific journal

Radio Techniques Incorporating Sparse Modeling
Toshihiko NISHIMURA, Yasutaka OGAWA, Takeo OHGANE, Junichiro HAGIWARA
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E104-A, 3, 591, 603, Institute of Electronics, Information and Communications Engineers (IEICE), Mar. 2021, [Peer-reviewed], [Invited]
Japanese, Scientific journal, Sparse modeling is one of the most active research areas in engineering and science. The technique provides solutions from far fewer samples exploiting sparsity, that is, the majority of the data are zero. This paper reviews sparse modeling in radio techniques. The first half of this paper introduces direction-of-arrival (DOA) estimation from signals received by multiple antennas. The estimation is carried out using compressed sensing, an effective tool for the sparse modeling, which produces solutions to an underdetermined linear system with a sparse regularization term. The DOA estimation performance is compared among three compressed sensing algorithms. The second half reviews channel state information (CSI) acquisitions in multiple-input multiple-output (MIMO) systems. In time-varying environments, CSI estimated with pilot symbols may be outdated at the actual transmission time. We describe CSI prediction based on sparse DOA estimation, and show excellent precoding performance when using the CSI prediction. The other topic in the second half is sparse Bayesian learning (SBL)-based channel estimation. A base station (BS) has many antennas in a massive MIMO system. A major obstacle for using the massive MIMO system in frequency-division duplex mode is an overhead for downlink CSI acquisition because we need to send many pilot symbols from the BS and to get the feedback from user equipment. An SBL-based channel estimation method can mitigate this issue. In this paper, we describe the outline of the method, and show that the technique can reduce the downlink pilot symbols.

An Evaluation of Design Framework for Min-Sum Irregular LDPC Decoders
Jimpu Suzuki, Hiroshi Tsutsui, Takeo Ohgane
Proc. APSIPA 2020, 110, 113, IEEE, Dec. 2020, [Peer-reviewed]
International conference proceedings

An Evaluation of a CNN-Based Parking Detection System with Webcams
Takuto Fukusaki, Hiroshi Tsutsui, Takeo Ohgane
Proc. APSIPA 2020, 100, 103, IEEE, Dec. 2020, [Peer-reviewed]
International conference proceedings

A Consideration on Accuracy Improvement in DOA Estimation of Two Targets with Deep Learning　　　　　　　　　　　　　　　
Yuya KASE, Toshihiko NISHIMURA, Takeo OHGANE, Yasutaka OGAWA, Takanori SATO, Daisuke KITAYAMA, Yoshihisa KISHIYAMA
Proc. ICETC 2020, P1-3, Dec. 2020, [Peer-reviewed]
International conference proceedings

A Preliminary Study on Behavior of GaBP Messages in Massive MIMO Signal Detection　　　　　　　　　　　　　　　
Daniel Akira ANDO, Toshihiko NISHIMURA, Takeo OHGANE, Yasutaka OGAWA, Junichiro HAGIWARA, Takanori SATO
Proc. ICETC 2020, K1-2, Dec. 2020, [Peer-reviewed]
International conference proceedings

Channel prediction of wideband OFDM systems in a millimeter-wave band based on multipath delay estimation
Yuta Takano, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
IEICE Communications Express, 9, 12, 561, 566, Institute of Electronics, Information and Communications Engineers (IEICE), Dec. 2020, [Peer-reviewed]
English, Scientific journal, Multi-user MIMO systems enable high capacity transmission. A base station, however, needs accurate channel state information (CSI). In time-varying environments, the CSI may be outdated at the actual transmission time. One of the solutions to this issue is channel prediction. The authors have proposed the prediction method using FISTA, a compressive sensing technique, for OFDM systems in a millimeter-wave band. Unfortunately, in realistic multipath environments, the prediction performance of the proposed technique degrades. In this letter, we examine the prediction performance in wider OFDM systems. It will be shown that FISTA reveals excellent performance in a sufficiently wide band case.

Fundamental Trial on DOA Estimation with Deep Learning
Yuya KASE, Toshihiko NISHIMURA, Takeo OHGANE, Yasutaka OGAWA, Daisuke KITAYAMA, Yoshihisa KISHIYAMA
IEICE Transactions on Communications, E103.B, 10, 1127, 1135, Institute of Electronics, Information and Communications Engineers (IEICE), 01 Oct. 2020, [Peer-reviewed]
English, Scientific journal, Direction of arrival (DOA) estimation of wireless signals has a long history but is still being investigated to improve the estimation accuracy. Non-linear algorithms such as compressed sensing are now applied to DOA estimation and achieve very high performance. If the large computational loads of compressed sensing algorithms are acceptable, it may be possible to apply a deep neural network (DNN) to DOA estimation. In this paper, we verify on-grid DOA estimation capability of the DNN under a simple estimation situation and discuss the effect of training data on DNN design. Simulations show that SNR of the training data strongly affects the performance and that the random SNR data is suitable for configuring the general-purpose DNN. The obtained DNN provides reasonably high performance, and it is shown that the DNN trained using the training data restricted to close DOA situations provides very high performance for the close DOA cases.

Performance Evaluation of Beam Shapes in a Two-Step-Precoded Massive MIMO System
Jumpei Yamamoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Daiki Takeda, Yoshihisa Kishiyama
IEICE TRANSACTIONS ON COMMUNICATIONS, E103B, 6, 703, 711, Jun. 2020, [Peer-reviewed]
English, Scientific journal

Maximum Ratio Transmission for OAM Mode Multiplexing Using Multiple UCAs
Ayano Yamamoto, Toshihiko Nishimura, Takeo Ohgane, Tomoya Tandai, Daisuke Uchida
2020 14TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP 2020), Mar. 2020, [Peer-reviewed]
English, International conference proceedings

A Pilot-less Narrowband Coherent FSK System Applying Phase Rotated Transmit Diversity with Suppression of Envelope Fluctuation　　　　　　　　　　　　　　　
Kanako YAMAGUCHI, Masatsugu HIGASHINAKA, Hiroyasu SANO, Atsushi OKAMURA, Takeo OHGANE, Toshihiko NISHIMURA
電子情報通信学会論文誌B, J103-B, 2, 100, 109, Feb. 2020, [Peer-reviewed]
Japanese, Scientific journal

Channel Prediction of Wideband OFDM Systems in a Millimeter-Wave Band Using Delay-Domain Multipath Detection
Yuta Takano, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane, Junichiro Hagiwara
2020 International Workshop on Antenna Technology (iWAT), IEEE, Feb. 2020, [Peer-reviewed]
International conference proceedings

A Study on Iterative Equalization with GaBP and Soft Successive Cancellation List Decoding in a Polar-Coded System
Kentaro Fukuda, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2019 22nd International Symposium on Wireless Personal Multimedia Communications (WPMC), IEEE, Nov. 2019, [Peer-reviewed]
International conference proceedings

A Study on Large-Scale Signal Detection Using Gaussian Belief Propagation in Overloaded Interleave Division Multiple Access
Wataru Kawabata, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2019 22nd International Symposium on Wireless Personal Multimedia Communications (WPMC), IEEE, Nov. 2019, [Peer-reviewed]
International conference proceedings

Performance Analysis of DOA Estimation of Two Targets Using Deep Learning
Yuya Kase, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Daisuke Kitayama, Yoshihisa Kishiyama
2019 22nd International Symposium on Wireless Personal Multimedia Communications (WPMC), 1, 6, IEEE, Nov. 2019, [Peer-reviewed]
International conference proceedings

A Study on Performance Improvement by CRC-Aided GaBP for Large-Scale SCMA Detection
Renjie Li, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2019 22nd International Symposium on Wireless Personal Multimedia Communications (WPMC), IEEE, Nov. 2019, [Peer-reviewed]
International conference proceedings

A Narrow-Band Coherent FSK Transmission System Using Phase Rotated Transmit Diversity with Suppression of Envelope Fluctuation
Kanako Yamaguchi, Masatsugu Higashinaka, Hiroyasu Sano, Atsushi Okamura, Takeo Ohgane, Toshihiko Nishimura
2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall), IEEE, Sep. 2019, [Peer-reviewed]
International conference proceedings

Loose Beamforming by Antenna Selection in a Multiuser Massive MIMO System
Shunta Nakamura, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2019 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), IEEE, Aug. 2019, [Peer-reviewed]
International conference proceedings

Evaluation of OAM Mode Multiplexing Considering Ground Reflection
Yamamoto, Ayano, Nishimura, Toshihiko, Ohgane, Takeo, Tandai, Tomoya, Uchida, Daisuke
2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), May 2019, [Peer-reviewed]
English, International conference proceedings

A Study on Layouts of Distributed Antenna Arrays in an Indoor Multi-User Massive MIMO System
Yuya Suzuki, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2019 International Conference on Computing, Networking and Communications (ICNC), IEEE, Feb. 2019, [Peer-reviewed]
International conference proceedings

Computational Complexity Reduction of Receive Weight Matrices in Massive MIMO SC-FDF†
Kensei Saito, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane, Junichiro Hagiwara
2019 International Conference on Computing, Networking and Communications (ICNC), IEEE, Feb. 2019, [Peer-reviewed]
International conference proceedings

Prediction of Time-Varying Multi-User MIMO Channels Based on DOA Estimation Using Compressed Sensing
Uehashi, Shunsuke, Ogawa, Yasutaka, Nishimura, Toshihiko, Ohgane, Takeo
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, 68, 1, 565, 577, Jan. 2019, [Peer-reviewed]
English, Scientific journal

Fundamentals of MIMO Technologies for 5G
Takeo Ohgane, Toshihiko Nishimura, Yasutaka Ogawa
電子情報通信学会誌, 101, 11, 1117, 1122, 電子情報通信学会, Nov. 2018, [Peer-reviewed], [Lead author]
Japanese, Scientific journal

Superposed 16-QAM Signal Detection Using GaBP in a Massive MIMO System
Watabe, Taisei, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka, Hagiwara, Junichiro
2018 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA ASC), 1416, 1420, Nov. 2018, [Peer-reviewed]
English, International conference proceedings

Performance Comparison of Compressed Sensing Algorithms for DOA Estimation of Multi-band Signals
Toyoki Hoshikawa, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Junichiro Hagiwara
2018 15th Workshop on Positioning, Navigation and Communications (WPNC), IEEE, Oct. 2018, [Peer-reviewed]
International conference proceedings

DOA Estimation of Two Targets with Deep Learning
Yuya Kase, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Daisuke Kitayama, Yoshihisa Kishiyama
2018 15th Workshop on Positioning, Navigation and Communications (WPNC), IEEE, Oct. 2018, [Peer-reviewed]
International conference proceedings

MIMO SC-FDE における受信ウェイトの補間精度 の劣化とその軽減法
齋藤 剣聖, 小川 恭孝, 西村 寿彦, 大鐘 武雄
電子情報通信学会論文誌B, J101.B, 7, Apr. 2018, [Peer-reviewed]
Japanese, Scientific journal

Performance Evaluation on Beam Shapes of a Large MIMO System
Yamamoto, Jumpei, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka, Takeda, Daiki, Kishiyama, Yoshihisa
2018 IEEE INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY (IWAT), Mar. 2018, [Peer-reviewed]
English, International conference proceedings

A Basic Study on Antenna Selection for Loose Beamforming in a Massive MIMO System
Koichi Inoue, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2018 IEEE INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY (IWAT), Mar. 2018, [Peer-reviewed]

Signal Detection with Belief Propagation in Faster-than-Nyquist Signaling
Kotaro Kihara, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2017 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA ASC 2017), 1790, 1794, Dec. 2017, [Peer-reviewed]

Development of Signal Processing Antennas in Mobile Communications　　　　　　　　　　　　　　　
Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEICE Trans. Commun., 100, 9, 658, 672, Sep. 2017, [Peer-reviewed], [Invited]
Japanese

Node Selection for Belief Propagation Based Channel Equalization
Mitsuyoshi Hagiwara, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E100B, 8, 1285, 1292, Aug. 2017, [Peer-reviewed]
English, Scientific journal

Serial and Parallel LLR Updates Using Damped LLR for LDPC Coded Massive MIMO Detection with Belief Propagation
Shuhei Tanno, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E100B, 8, 1277, 1284, Aug. 2017, [Peer-reviewed]
English, Scientific journal

A Performance Comparison of Compressed Sensing Algorithms for Scatterer Detection
Daisuke Abe, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2017 INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY: SMALL ANTENNAS, INNOVATIVE STRUCTURES, AND APPLICATIONS (IWAT), 74, 77, Mar. 2017, [Peer-reviewed]
English, International conference proceedings

Performance Comparison of Full-Dimension MIMO Systems with Different Base Station Places
Shun Nishizaki, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2017 INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY: SMALL ANTENNAS, INNOVATIVE STRUCTURES, AND APPLICATIONS (IWAT), 335, 338, Mar. 2017, [Peer-reviewed]
English, International conference proceedings

DOA Estimation of Signals with Frequency Characteristics and Different Powers using a Compressed Sensing Technique
Taiki Endo, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2016 IEEE INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY (IWAT), 192, 195, 2016, [Peer-reviewed]
English, International conference proceedings

Suppression of Scattering Waves from the Outside of a Search Area Using a Gating Technique in Compressed Sensing Based Scatterer Detection
Daisuke Abe, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2016 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP), 1008, 1009, 2016, [Peer-reviewed]
English, International conference proceedings

4. Massive MIMO
Ohgane Takeo, Nishimura Toshihiko, Ogawa Yasutaka
The Journal of The Institute of Image Information and Television Engineers, 70, 1, 17, 22, The Institute of Image Information and Television Engineers, 2016, [Peer-reviewed]
Japanese

Node Selection and LLR Damping for Channel Equalization with Belief Propagation
Mitsuyoshi Hagiwara, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016), 483, 487, 2016, [Peer-reviewed]
English, International conference proceedings

A Comparison of Serial and Parallel LLR Updates for LDPC Coded Massive MIMO Detection with Belief Propagation
Shuhei Tanno, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016), 473, 477, 2016, [Peer-reviewed]
English, International conference proceedings

On Normalized Belief of Gaussian BP in Correlated Large MIMO Channels
Takumi Takahashi, Shinsuke Ibi, Takeo Ohgane, Seiichi Sampei
PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016), 458, 462, 2016, [Peer-reviewed]
English, International conference proceedings

BP-based Detection of Spatially Multiplexed 16-QAM Signals in a Fully Massive MIMO System
Usami, Tomoya, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka
2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), 1, 5, 2016, [Peer-reviewed]
English, International conference proceedings

Channel Prediction Using Compressed Sensing in Multi-User MIMO Systems
Uehashi, Shunsuke, Ogawa, Yasutaka, Nishimura, Toshihiko, Ohgane, Takeo
2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), 1, 6, 2016, [Peer-reviewed]
English, International conference proceedings

Performance Evaluation of Alternative Routing in a Wireless Mesh Network with an Adaptive Array
Kosuke Suzuki, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), 1, 6, 2016, [Peer-reviewed]
English, International conference proceedings

Parameter Settings on DOA Estimation of Multi-band Signals Using a Compressed Sensing Technique
Toshihiko Nishimura, Taiki Endo, Takeo Ohgane, Yasutaka Ogawa
2016 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA), 1, 6, 2016, [Peer-reviewed]
English, International conference proceedings

A Throughput Evaluation of an Over-Distributed Antenna System with Limited Pilot Resources
Yuki Nakanishi, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yusuke Ohwatari, Yoshihisa Kishiyama
IEICE TRANSACTIONS ON COMMUNICATIONS, E98B, 8, 1465, 1473, Aug. 2015, [Peer-reviewed]
English, Scientific journal

Iterative angle-and-time-domain gating technique for time-reversal MUSIC imaging
Heedong Choi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
SIGNAL PROCESSING, 111, 39, 49, Jun. 2015, [Peer-reviewed]
English, Scientific journal

Comparison of Kalman Smoother to Wiener Smoother in Practical OFDM Channel Estimation
Junichiro Hagiwara, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2015 21ST ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC), 454, 459, 2015, [Peer-reviewed]
English, International conference proceedings

Performance Evaluation of Full-Dimension MIMO in Indoor Line-of-Sight Environments
Hayato Fukuda, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2015 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), 159, 164, 2015, [Peer-reviewed]
English, International conference proceedings

Channel Prediction Techniques for a Multi-User MIMO System in Time-Varying Environments
Yamaguchi Kanako, Huu Phu Bui, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo
IEICE TRANSACTIONS ON COMMUNICATIONS, E97B, 12, 2747, 2755, Dec. 2014, [Peer-reviewed]

Channel Prediction Techniques for a Multi-User MIMO System in Time-Varying Environments
Yamaguchi, Kanako, Huu Phu Bui, Ogawa, Yasutaka, Nishimura, Toshihiko, Ohgane, Takeo
IEICE TRANSACTIONS ON COMMUNICATIONS, E97B, 12, 2747, 2755, Dec. 2014, [Peer-reviewed]
English, Scientific journal

DOA Estimation for Multi-Band Signal Sources Using Compressed Sensing Techniques with Khatri-Rao Processing
Terada, Tsubasa, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo, Yamada, Hiroyoshi
IEICE TRANSACTIONS ON COMMUNICATIONS, E97B, 10, 2110, 2117, Oct. 2014, [Peer-reviewed]
English, Scientific journal

A Multi-user MIMO System in Time-varying Environments
OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo
電子情報通信学会誌 = The journal of the Institute of Electronics, Information and Communication Engineers, 97, 4, 285, 289, 一般社団法人電子情報通信学会, Apr. 2014, [Peer-reviewed]
Japanese, マルチユーザMIMOシステムの下り回線においては,通常,ユーザ間の干渉,及び,同一ユーザの複数ストリーム間の干渉がなくなるように基地局は送信ウェイトを決定し,それを信号に乗算して伝送が行われる.一方,ユーザ端末や周囲の散乱体の移動により,一般に,チャネルは時間変動する.このような環境では,送信ウェイトを決定したときのチャネルと実際に送信を行うときのチャネルに変動があるため干渉が発生し,特性が劣化する.この問題はチャネルを予測することにより軽減が可能である.本稿では,時変動チャネルがマルチユーザMIMOシステムに与える影響とチャネル予測の効果を明らかにする.

DOA Estimation of Multi-band Signals Using a Compressed Sensing Technique
Terada, Tsubasa, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo, Yamada, Hiroyoshi
2014 INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY: "SMALL ANTENNAS, NOVEL EM STRUCTURES AND MATERIALS, AND APPLICATIONS" (IWAT), 359, 362, 2014, [Peer-reviewed]
English, International conference proceedings

DOA Estimation by Applying Compressed Sensing Techniques
Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION, 121, 122, 2014, [Peer-reviewed]
English, International conference proceedings

DOA Estimation of Correlated Wideband Signals by using Multi-band EM Algorithm
Yamada, Hiroyoshi, Shirai, Satoshi, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo, Yamaguchi, Yoshio
2014 USNC-URSI RADIO SCIENCE MEETING (JOINT WITH AP-S SYMPOSIUM), 205, 205, 2014, [Peer-reviewed]
English

Performance Investigation of Reduced Complexity Bit-Flipping using Variable Thresholds and Noise Perturbation
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka
2014 16TH INTERNATIONAL CONFERENCE ON ADVANCED COMMUNICATION TECHNOLOGY (ICACT), 206, +, 2014, [Peer-reviewed]
English, International conference proceedings

Antenna splitting in a distributed antenna system for a multiuser MIMO transmission
Yuki Nakanishi, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yusuke Ohwatari, Yoshihisa Kishiyama
2014 IEEE 25TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATION (PIMRC), 193, 197, 2014, [Peer-reviewed]
English, International conference proceedings

Behavior of a Multi-User MIMO System in Time-Varying Environments
Yasutaka Ogawa, Kanako Yamaguchi, Huu Phu Bui, Toshihiko Nishimura, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E96B, 10, 2364, 2371, Oct. 2013, [Peer-reviewed], [Invited]
English, Scientific journal

Performance Evaluation of a Multi-User MIMO System With Prediction of Time-Varying Indoor Channels
Huu Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61, 1, 371, 379, Jan. 2013, [Peer-reviewed]
English, Scientific journal

Considerations on a Multi-User MIMO System Using Channel Prediction Based on an AR Model
Yamaguchi, Kanako, Huu Phu Bui, Ogawa, Yasutaka, Nishimura, Toshihiko, Ohgane, Takeo
2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), 550, +, 2013, [Peer-reviewed]
English, International conference proceedings

DOA Estimation of Multi-band Signals Using a Sparse Signal Reconstruction Method
Terada, Tsubasa, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo
2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), 866, 867, 2013, [Peer-reviewed]
English, International conference proceedings

Low-complexity Detection Based on Belief Propagation in a Massive MIMO System
Wataru Fukuda, Takashi Abiko, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yusuke Ohwatari, Yoshihisa Kishiyama
2013 IEEE 77TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), 1, 5, 2013, [Peer-reviewed]
English, International conference proceedings

Complexity Reduction for Signal Detection Based on Belief Propagation in a Massive MIMO System
Wataru Fukuda, Takashi Abiko, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yusuke Ohwatari, Yoshihisa Kishiyama
2013 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATIONS SYSTEMS (ISPACS), 245, 250, 2013, [Peer-reviewed]
English, International conference proceedings

A Study on a Multi-User Single-Carrier E-SDM Scheme in Wideband Transmissions
Keita Harada, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2013 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATIONS SYSTEMS (ISPACS), 240, 244, 2013, [Peer-reviewed]
English, International conference proceedings

An EXIT chart analysis for belief-propagation based detection in a large-scale MIMO system
Takashi Abiko, Wataru Fukuda, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yusuke Ohwatari, Yoshihisa Kishiyama
IEEE Vehicular Technology Conference, 1, 5, IEEE, 2013, [Peer-reviewed]
English, International conference proceedings

Impact on Inter-Cell Interference of Reference Signal for Interference Rejection Combining Receiver in LTE-Advanced Downlink
Yousuke Sano, Yusuke Ohwatari, Nobuhiko Miki, Yuta Sagae, Yukihiko Okumura, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
IEICE TRANSACTIONS ON COMMUNICATIONS, E95B, 12, 3728, 3738, Dec. 2012, [Peer-reviewed]
English, Scientific journal

Time-Reversal MUSIC Imaging with Time-Domain Gating Technique
Heedong Choi, Yasutaka Ogawa, Toshihiko Nishmura, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E95B, 7, 2377, 2385, Jul. 2012, [Peer-reviewed]
English, Scientific journal

A DSP and FPGA testbed for teaching and research of wireless communications
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka
INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING EDUCATION, 49, 3, 232, 242, Jul. 2012, [Peer-reviewed]
English, Scientific journal

Considerations on a frequency correlation for distributed antenna systems　　　　　　　　　　　　　　　
Kanako Yamaguchi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2012 International Symposium on Antennas and Propagation (ISAP), 1128, 1131, 2012, [Peer-reviewed]
English

Angle-and-time-domain gating technique for time-reversal MUSIC imaging
Heedong Choi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2012 International Symposium on Antennas and Propagation (ISAP), 86, 89, 2012, [Peer-reviewed]
English

Selective Ultrawideband Time-Reversal MUSIC using a Time-Domain Gating Technique
Heedong Choi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2012 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), 2012, [Peer-reviewed]
English, International conference proceedings

A study on adaptive thresholds for reduced complexity bit-flip decoding
Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2012 14th International Conference on Advanced Communication Technology (ICACT), 497, 501, 2012, [Peer-reviewed]
English

A Study on Transmit Beamforming at Source Node in MISO-SISO/MIMO-MIMO AF Relays
Naohito Kiyomi, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2012 IEEE 75TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), 1, 5, 2012, [Peer-reviewed]
English, International conference proceedings

Reduced-Complexity Single-Carrier E-SDM for Wideband Transmissions
Cristian Davidescu, Yasutaka Ogawa, Julian Webber, Toshihiko Nishimura, Takeo Ohgane
2012 IEEE 75TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), 1, 5, 2012, [Peer-reviewed]
English, International conference proceedings

Development of a channel emulator for evaluation of MIMO-OFDM and SC-FDMA systems
Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
APSIPA ASC 2011 - Asia-Pacific Signal and Information Processing Association Annual Summit and Conference 2011, 492, 495, 2011
International conference proceedings

Noise reduction method based on the gating technique for time-reversal MUSIC imaging
Heedong Choi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
iWEM2011 - IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, 140, 144, 2011, [Peer-reviewed]
English, International conference proceedings

Accuracy Evaluation of DOA Estimation with Multi-band Signals
Kyouhei Maeda, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2011 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (APSURSI), 835, 838, 2011, [Peer-reviewed]
English, International conference proceedings

Multi-User MIMO System with Channel Prediction for Time-Varying Environments
Huu Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2011 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (APSURSI), 59, 62, 2011, [Peer-reviewed]
English, International conference proceedings

Investigation of simple threshold shifting for bit-flip decoding.
Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
14th International Symposium on Wireless Personal Multimedia Communications, WPMC 2011, Brest, France, October 3-7, 2011, 1, 5, IEEE, 2011, [Peer-reviewed]

A fundamental study on routing and scheduling for multi-hop wireless networks with adaptive array.
Daiki Takeda, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
14th International Symposium on Wireless Personal Multimedia Communications, WPMC 2011, Brest, France, October 3-7, 2011, 1, 5, IEEE, 2011, [Peer-reviewed]

Performance of a MIMO-OFDM eigenbeamforming system in a correlated channel
Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
APSIPA ASC 2010 - Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, 757, 760, 2010
International conference proceedings

Measurement-Based Evaluation of a Multiuser MIMO System in an Indoor Time-Varying Environment
Huu Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2010 IEEE 72ND VEHICULAR TECHNOLOGY CONFERENCE FALL, 1, 5, 2010, [Peer-reviewed]
English, International conference proceedings

Optimum Transmit Beamforming in an Interactive Wireless Relay System with Network Coding
Sakiko Matsuya, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2010 IEEE 21ST INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC), 2093, 2098, 2010, [Peer-reviewed]
English, International conference proceedings

A Generalized Approach to Block Diagonalization for Multiuser MIMO Downlink
Tomoki Sada, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2010 IEEE 21ST INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC), 504, 509, 2010, [Peer-reviewed]
English, International conference proceedings

Channel Characteristics and Performance of MIMO E-SDM Systems in an Indoor Time-Varying Fading Environment
Huu Phu Bui, Hiroshi Nishimoto, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING, 2010, 2010, [Peer-reviewed]
English, Scientific journal

Performance Evaluation of MIMO-UWB Systems Using Measured Propagation Data and Proposal of Timing Control Scheme in LOS Environments
Masaki Takanashi, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E92B, 8, 2698, 2707, Aug. 2009, [Peer-reviewed]
English, Scientific journal

Performance Evaluation of Multiuser MIMO E-SDM Systems in Time-Varying Fading Environments
Hun Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E92B, 7, 2374, 2388, Jul. 2009, [Peer-reviewed]
English, Scientific journal

MIMO Channel Technologies for Mobile Radio(Simulation Methods in Mobile Communication Networks)
Ohgane Takeo, Ogawa Yasutaka, Nishimura Toshihiko
Journal of the Japan Society for Simulation Technology, 28, 2, 86, 90, 日本シミュレーション学会, Jun. 2009, [Peer-reviewed]
Japanese

Subblock Processing for Frequency-Domain Turbo Equalization under Fast Fading Environments
Keiichi Kambara, Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E92B, 5, 1466, 1474, May 2009, [Peer-reviewed]
English, Scientific journal

MIMO Technologies for Ultra High-Speed Wireless Transmission
Ogawa Yasutaka, Ohgane Takeo, Nishimura Toshihiko
IEICE Communications Society Magazine, 2009, 11, 11_32, 11_38, The Institute of Electronics, Information and Communication Engineers, 2009, [Peer-reviewed]
Japanese, 数十Gbit/s以上の超高速通信が必要になった場合，MIMO伝送が必須技術となることは容易に想像できる．しかし，実際に超高速伝送を実現できるかどうかは，アンテナ本数のみならず，周波数帯，伝搬環境，実装技術に大きく依存する．特に超高速伝送が使用されると考えられる見通しのある解放空間では，空間相関が高くなるため，MIMO伝送の効果が減少する．したがって，アンテナ配置や伝搬構造の能動的最適化など，改善手法について述べる．

A Study on Decision-Feedback Assisted Channel Tracking and Channel Prediction for IEEE802.16e Based OFDM System
KIM Sang-Woo, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 92, 1, 185, 195, The Institute of Electronics, Information and Communication Engineers, Jan. 2009, [Peer-reviewed]
Japanese, 周波数有効利用やマルチパス対策においてOFDMは有効な伝送方式である.しかし,高速移動によるマルチパスフェージング環境下では,プリアンブルで推定したチャネルが時間とともに変動するため,それに続くデータ区間においてその変動を補償する必要がある.本論文では,その補償法として判定帰還を用いたチャネル更新法を検討し,帰還系列の精度を向上させる手法を新たに提案した.また,追従特性をより改善するため線形予測を導入し,予測係数を少ないデータから決定する二つの手法について検討した.シミュレーションによる特性評価から,これらの提案手法が有効であることが確認できた.

Hardware development of a MIMO pseudo E-SDM system and real-time channel emulator
Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
APSIPA ASC 2009 - Asia-Pacific Signal and Information Processing Association 2009 Annual Summit and Conference, 684, 687, 2009
International conference proceedings

An implementation of a CMA adaptive array for high speed GMSK transmission in mobile communications
Takeo Ohgane, Takanori Shimura, Naoto Matsuzawa, Hideichi Sasaoka
Adaptive Antennas for Wireless Communications, 673, 679, John Wiley and Sons Inc., 01 Jan. 2009, [Peer-reviewed]
English, In book

Tri-diagonalizing Approach on Frequency Domain Equalization in a Doubly-selective Channel
Keisuke Saito, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8, 2688, 2692, 2009, [Peer-reviewed]
English, International conference proceedings

A Study on Separation of Two Close DOAs by Using Wide-band Signals
Toshihiko Nishimura, Ysutaka Ogawa, Takeo Ohgane
2009 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ISPACS 2009), 240, 243, 2009, [Peer-reviewed]
English, International conference proceedings

Cooperative Communication Using a Virtual MIMO System with a Feedback Channel for Uplink Transmission in Cellular Radio
Yuta Saito, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, 1084, 1088, 2009, [Peer-reviewed]
English, International conference proceedings

Performance of MIMO-OFDM E-SDM Systems Using Circular Arrays
Huu Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2009 IEEE 20TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, 2459, 2463, 2009, [Peer-reviewed]
English, International conference proceedings

Experimental MIMO Pseudo E-SDM and Channel Emulation System
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka
2009 IEEE 20TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, 1039, 1043, 2009, [Peer-reviewed]
English, International conference proceedings

Blind Detection of Partial Transmit Sequence in a Coded OFDM System
Koji Shibata, Julian Webber, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8, 2705, 2710, 2009, [Peer-reviewed]
English, International conference proceedings

Precise DOA Estimation Using SAGE Algorithm with a Cylindrical Array
Masaki Takanashi, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E91B, 11, 3784, 3787, Nov. 2008, [Peer-reviewed]
English, Scientific journal

Soft Decision Directed Channel Estimation with Interference Cancellation for a MIMO System Using Iterative Equalization and Decoding
Masatsugu Higashinaka, Hiroshi Kubo, Akihiro Okazaki, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E91A, 10, 2787, 2797, Oct. 2008, [Peer-reviewed]
English, Scientific journal

Frequency Offset Estimation and Transmit/Receive Weight Control in an Uplink Channel Using a Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 91, 9, 940, 947, The Institute of Electronics, Information and Communication Engineers, Sep. 2008, [Peer-reviewed]
Japanese, 将来の高速移動通信は現在よりも高い周波数帯を使用することが考えられる.この場合,端末の電源がバッテリーであるため,上り回線の送信電力が制限され,通信品質は劣化する.そこで,近傍の複数端末が送信データを共有して互いに協力し合う協調無線が注目されている.しかし,仮想的なアレーアンテナを形成してビームフォーミングを行う場合,各端末は異なる発振器で動作しているため,キャリヤ周波数のずれによる端末周波数オフセットの存在が通信特性に大きな影響を与えてしまう.そこで,本論文では過去のチャネル情報を用いた端末周波数オフセット推定法とそれを用いた送信側での補償法,及び,RLSアルゴリズムを用いた受信ウェイト制御との組合せについて検討し,計算機シミュレーションによりその特性について評価する.その結果,これらの制御を組み合わせることで,特性を大きく改善できることが確認された.

Performance of MIMO E-SDM systems using channel prediction in actual time-varying indoor fading environments
Huu Phu Bui, Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E91B, 6, 1713, 1723, Jun. 2008, [Peer-reviewed]
English, Scientific journal

Measurement-based performance evaluation of coded MIMO-OFDM spatial multiplexing with MMSE spatial filtering in an indoor line-of-sight environment
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E91B, 5, 1648, 1652, May 2008, [Peer-reviewed]
English, Scientific journal

Studies on an iterative frequency domain channel estimation technique for MIMO-UWB communications
Masaki Takanashi, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E91B, 4, 1084, 1094, Apr. 2008, [Peer-reviewed]
English, Scientific journal

Subblock processing in MMSE-FDE under fast fading environments
Keiichi Kambara, Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, 26, 2, 359, 365, Feb. 2008, [Peer-reviewed]
English, Scientific journal

Subblock processing for frequency-domain turbo equalization under fast fading environments
K. Kambara, H. Nishimoto, T. Nishimura, T. Ohgane, Y. Ogawa
IEEE Vehicular Technology Conference, 2008, [Peer-reviewed]
English, International conference proceedings

Channel characteristics in actual SISO and MIMO propagation environments
Bui Huu Phu, Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2008 SECOND INTERNATIONAL CONFERENCE ON COMMUNICATIONS AND ELECTRONICS, 356, 361, 2008, [Peer-reviewed]
English, International conference proceedings

Subblock Processing for Frequency-domain Turbo Equalization Under Fast Fading Environments
K. Kambara, H. Nishimoto, T. Nishimura, T. Ohgane, Y. Ogawa
68TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, FALL 2008, 839, 843, 2008, [Peer-reviewed]
English, International conference proceedings

Imperfect Block Diagonalization for Multiuser MIMO Downlink
Hiroshi Nishimoto, Shohei Kato, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, 1960, 1964, 2008, [Peer-reviewed]
English, International conference proceedings

Multiuser MIMO E-SDM Systems: Performance Evaluation and Improvement in Time-Varying Fading Environments
Huu Phu Bui, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
GLOBECOM 2008 - 2008 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, 3303, 3307, 2008, [Peer-reviewed]
English, International conference proceedings

Measurement-based performance evaluation of MIMO spatial multiplexing in a multipath-rich indoor environment
Hiroshi Nishimoto, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 55, 12, 3677, 3689, Dec. 2007, [Peer-reviewed]
English, Scientific journal

Pseudo eigenbeam-space division multiplexing (PE-SDM) in frequency-selective MIMO channels
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E90B, 11, 3197, 3207, Nov. 2007, [Peer-reviewed]
English, Scientific journal

Arrangement of scattering points in Jakes' model for i.i.d. time-varying MIMO fading
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E90B, 11, 3311, 3314, Nov. 2007, [Peer-reviewed]
English, Scientific journal

Comparison of Reduction Schemes of Feedback Amount in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 90, 9, 885, 895, The Institute of Electronics, Information and Communication Engineers, Sep. 2007, [Peer-reviewed]
Japanese, MIMO-OFDM空間分割多重において,送信側でチャネル情報(CSI)が既知,若しくは,受信側から用いるべき送信ウェートが報知される場合,固有ビーム空間分割多重(E-SDM)方式を用いることができ,MIMOチャネル最大の容量が得られる.筆者らはこれまで時間領域で最小二乗法を適用し,推定したCSIのうち,主要な成分のみをフィードバックすることにより,情報量が削減できることを報告してきた.本論文では,筆者らが提案しているCSIフィードバック手法及びコードブックを用いた送信ウェートフィードバック手法について比較検討を行った.その結果,各手法におけるフィードバック情報量をほぼ等しくした場合,情報量が少ない4×2MIMOにおいては送信ウェート行列をフィードバックする手法の特性が,情報量が多い4×2MIMO,及び4×4MIMOにおいてはCSIフィードバック手法の特性が良好であることが確認された.

MIMO E-SDM transmission performance in an actual indoor environment
Hiroshi Nishimoto, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E90B, 6, 1474, 1486, Jun. 2007, [Peer-reviewed]
English, Scientific journal

Robust MIMO-OFDM E-SDM systems with low complexity in time-varying indoor fading environments
Bui Huu Phu, Toshihiko Nishimura, Hiroshi Nishimoto, Takeo Ohgane, Yasutaka Ogawa
IEEE Vehicular Technology Conference, 1322, 1326, 2007, [Peer-reviewed]
English, International conference proceedings

Channel estimation with space-time windowing in MIMO PE-SDM transmission
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
IEEE Vehicular Technology Conference, 541, 545, 2007, [Peer-reviewed]
English, International conference proceedings

Performance considerations on MIMO spatial multiplexing from the viewpoint of antennas and propagation
Y. Ogawa, H. P. Bui, H. Nishimoto, T. Nishimura, T. Ohgane
IET Seminar Digest, 2007, 11961, 1, 11, 2007, [Peer-reviewed]
English, International conference proceedings

On the performance of MIMO E-SDM systems with channel prediction in indoor time-varying fading environments
Huu Phu Bui, Toshihiko Nishimura, Hiroshi Nishimoto, Yasutaka Ogawa, Takeo Ohgane
2007 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-12, 209, 212, 2007, [Peer-reviewed]
English, International conference proceedings

Doppler spectrum and performance of E-SDM systems in indoor time-varying MIMO channels
Huu Phu Bui, Hiroshi Nishimoto, Toshihiko Nishimura, Yasutaka Ogmata, Takeo Ohgane
2007 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-12, 1245, 1248, 2007, [Peer-reviewed]
English, International conference proceedings

Practical performance of coded MIMO-OFDM spatial multiplexing in an actual indoor environment
Hiroshi Nishimoto, Tosbihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2007 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-12, 3538, 3541, 2007, [Peer-reviewed]
English, International conference proceedings

MIMO-UWB systems with parallel interference canceller using timing control scheme in LOS environments
Masaki Takanashi, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9, 1601, 1605, 2007, [Peer-reviewed]
English, International conference proceedings

Subblock processing for MMSE-FDE under fast fading environments
K. Kambara, H. Nishimoto, T. Nishimura, Y. Ogawa, T. Ohgane
2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 2190, 2194, 2007, [Peer-reviewed]
English, International conference proceedings

Pseudo eigenbeam transmission technique in frequency selective MIMO channels
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 2068, 2072, 2007, [Peer-reviewed]
English, International conference proceedings

Robust performance of MIMO E-SDM systems in actual time-varying indoor fading environments
Bui Huu Phu, Toshihiko Nishimura, Hiroshi Nishimoto, Yasutaka Ogawa, Takeo Ohgane
2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 1460, 1464, 2007, [Peer-reviewed]
English, International conference proceedings

Robust MIMO-OFDM E-SDM systems with low complexity in time-varying indoor fading environments
Bui Huu Phu, Toshihiko Nishimura, Hiroshi Nishimoto, Takeo Ohgane, Yasutaka Ogawa
2007 IEEE 66TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, 1322, 1326, 2007, [Peer-reviewed]
English, International conference proceedings

Channel estimation with space-time windowing in MIMO PE-SDM transmission
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2007 IEEE 66TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, 541, 545, 2007, [Peer-reviewed]
English, International conference proceedings

High throughput performance of PE-SDM in MIMO single-carrier systems with MMSE-FDE
Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa
2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, 1852, 1856, 2007, [Peer-reviewed]
English, International conference proceedings

Channel extrapolation techniques for E-SDM system in time-varying fading environments
Hun Phu Bui, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
IEICE TRANSACTIONS ON COMMUNICATIONS, E89B, 11, 3083, 3092, Nov. 2006, [Peer-reviewed]
English, Scientific journal

Reduction of the Amount of CSI Feedback in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 89, 9, 1765, 1775, The Institute of Electronics, Information and Communication Engineers, Sep. 2006, [Peer-reviewed]
Japanese, 送受信側に複数のアンテナを設置し,各送信アンテナごとに独立したOFDM信号を送信するMIMO-OFDM空間分割多重では,マルチパス環境においても符号問干渉なしに伝送速度の向上が期待できる.更に,送信側でチャネル情報(CSI)が既知の場合,MIMOチャネルにおける最大スループットを得る固有ビーム空間分割多重(E-SDM)方式を用いることができる.しかしながら,OFDMでは各サブキャリヤごとにCSIをフィードバックする必要があり,通信容量を圧迫してしまう.本論文では,筆者らが以前より提案している時間領域で最小二乗法を適用し,推定したCSIをフィードバックすることで情報量を削減でき,更に良好な特性が得られることを示している.

A Study of MIMO Transmission for W-CDMA Uplink Channels
TANAKA Toyohisa, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 89, 2, 264, 277, The Institute of Electronics, Information and Communication Engineers, Feb. 2006, [Peer-reviewed]
Japanese, 第3世代の移動通信方式として既にサービスが提供されているW-CDMAは,3rd Generation Partnership Project (3GPP)で引き続き性能向上のため仕様策定が行われている.下り回線に関しては最高データレート14.0Mbit/sのHigh Speed Downlink Packet Access (HSDPA)が規定され,更にMIMOの適用が検討されている.本論文では,W-CDMA方式の上り回線にMIMO伝送を適用した場合について,シングルユーザでの通信を対象として計算機シミュレーションにより検討した.3GPPのRelease99規格で仕様化されているチャネルコーディング,拡散方法を用いて,12.2kbit/s,384kbit/s,更に2,048kbit/sのデータレートについて評価した.特に遅延波の存在する周波数選択性フェージング環境下で,チャネルの状態に応じて送信電力を制御できるE-SDM (Eigen Space Division Multiplexing)アルゴリズムが有効であることが分かった.

Transmit and receive timing control in LOS MIMO-UWB environments　　　　　　　　　　　　　　　
Masaki Takanashi, Toshihiko Nishimura, Yasutaka Ogawa, Takeo Ohgane
Progress in Electromagnetics Research Symposium, 605, 609, Electromagnetics Academy, 2006
English, International conference proceedings

Reduction of the amount of channel state information feedback in MIMO-OFDM eigenbeam-space division multiplexing systems
Yusuke Ohwatari, Bui Huu Phu, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
IEEE Vehicular Technology Conference, 401, 405, 2006, [Peer-reviewed]
English, International conference proceedings

Indoor Experiments of an E-SDM Testbed with Channel Prediction
Toshihiko Nishimura, Yasuo Hata, Takeo Ohgane, Yasutaka Ogawa
2006 IEEE 63RD VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 2285, 2289, 2006, [Peer-reviewed]
English, International conference proceedings

Extrapolation of Time-Varying MIMO Channels for an E-SDM System
Bui Huu Phu, Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura
2006 IEEE 63RD VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 1748, 1752, 2006, [Peer-reviewed]
English, International conference proceedings

Reduction of the Amount of Channel State Information Feedback in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
Yusuke Ohwatari, Bui Huu Phu, Yasutaka Ogawa, Toshihiko Nishimura, Takeo Ohgane
2006 IEEE 64TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, 401, 405, 2006, [Peer-reviewed]
English, International conference proceedings

Simplification of transmit resource control in E-SDM with adaptive modulation
Toshihiko Nishimura, Yasuo Hata, Takeo Ohgane, Yasutaka Ogawa
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 1, 5, IEEE, 2006, [Peer-reviewed]
English, International conference proceedings

Novel spatiotemporal equalization based on cascaded connection of multibeam adaptive array and multi-input MLSE
Y Tanabe, A Hanaki, T Ohgane, Y Ogawa
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 4, 6, 2716, 2725, Nov. 2005, [Peer-reviewed]
English, Scientific journal

Novel spatiotemporal equalization based on cascaded connection of multibeam adaptive array and multi-input MLSE
Y Tanabe, A Hanaki, T Ohgane, Y Ogawa
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 4, 6, 2716, 2725, Nov. 2005, [Peer-reviewed]
English, Scientific journal

Estimation of Channel and Frequency Offset in a MIMO-OFDM Space Division Multiplexing System
NAKAMURA Yuichiro, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 88, 9, 1813, 1820, The Institute of Electronics, Information and Communication Engineers, Sep. 2005, [Peer-reviewed]
Japanese, マルチパス環境下で, 周波数選択性フェージングを受けにくいOFDM方式は, 無線LANに利用されている.また, 送受信側の双方に複数のアンテナを設置し, 各送信アンテナから独立なOFDM信号を送ることによって, 100Mbit/sを超える高速伝送を実現するMIMO-OFDM空間分割多重方式の研究が行われている.本論文では, MIMO-OFDM空間分割多重について, 筆者らが以前より提案している時間領域で最小二乗法を適用しチャネル推定を行う方法を, チャネルと送受信機間の周波数オフセット推定法に拡張し, IEEE802.11aと同じプリアンブルの長さで両者の推定が可能であることを示している.

Direction-of-Arrival Estimation of Coherent Signals Using a Cylindrical Array
TAKANASHI Masaki, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo
IEICE Trans Commun (Inst Electron Inf Commun Eng), E88-B, 6, 2588, 2596, Jun. 2005, [Peer-reviewed]
English

Direction-of-arrival estimation of coherent signals using a cylindrical array
M Takanashi, T Nishimura, Y Ogawa, T Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E88B, 6, 2588, 2596, Jun. 2005, [Peer-reviewed]
English, Scientific journal

Applications of space division multiplexing and those performance in a MIMO channel
T Ohgane, T Nishimura, Y Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E88B, 5, 1843, 1851, May 2005, [Peer-reviewed]
English, Scientific journal

Applications of space division multiplexing and those performance in a MIMO channel
Takeo Ohgane, Toshihiko Nishimura, Yasutaka Ogawa
IEICE Transactions on Communications, E88-B, 5, 1843, 1851, Institute of Electronics, Information and Communication, Engineers, IEICE, 2005, [Peer-reviewed]
English, Scientific journal

Performance of MIMO spatial multiplexing in indoor line-of-sight environments
Yasutaka Ogawa, Hiroshi Nishimoto, Toshihiko Nishimura, Takeo Ohgane
IEEE Vehicular Technology Conference, 4, 2398, 2402, Institute of Electrical and Electronics Engineers Inc., 2005, [Peer-reviewed]
English, International conference proceedings

Performance of MIMO spatial multiplexing in indoor line-of-sight environments
Y Ogawa, H Nishimoto, T Nishimura, T Ohgane
VTC2005-FALL: 2005 IEEE 62ND VEHICULAR TECHNOLOGY CONFERENCE, 1-4, PROCEEDINGS, 2398, 2402, 2005, [Peer-reviewed]
English, International conference proceedings

A simplified iterative processing of soft MIMO detector and turbo decoder in a spatially multiplexed system
K Sumii, T Nishimura, T Ohgane, Y Ogawa
VTC2005-SPRING: 2005 IEEE 61ST VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, PROCEEDINGS, 882, 886, 2005, [Peer-reviewed]
English, International conference proceedings

Performance of 2x2 MIMO spatial multiplexing in indoor environments
Y Ogawa, H Nishimoto, T Nishimura, T Ohgane
2005 IEEE/ACES International Conference on Wireless Communications and Applied Computational Electromagnetics, 486, 489, 2005, [Peer-reviewed]
English, International conference proceedings

Compensation of channel information error using first order extrapolation in eigenbeam space division multiplexing (E-SDM)
T Nishimura, T Tsutsumi, T Ohgane, Y Ogawa
2005 IEEE/ACES INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS AND APPLIED COMPUTATIONAL ELECTROMAGNETICS, 44, 47, 2005, [Peer-reviewed]
English, International conference proceedings

Channel estimation and signal detection for space division multiplexing in a MIMO-OFDM system
Y Ogawa, K Nishio, T Nishimura, T Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E88B, 1, 10, 18, Jan. 2005, [Peer-reviewed]
English, Scientific journal

An Impact of Channel State Information Error on SDM Applications
TSUTSUMI Takahiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 87, 9, 1496, 1504, The Institute of Electronics, Information and Communication Engineers, Sep. 2004, [Peer-reviewed]
Japanese, 各種空間分割多重方式について,チャネル情報に誤差がある場合の誤り率特性を比較検討した.また,固有ビーム空間分割多重(E-SDM)方式と重み付きSDM (W-SDM)においては,一次外挿法を用いることにより,特性の改善を図った.その結果,チャネルの時間変動が大きい場合には,送信側で処理を行わない結合推定を用いたSDM (JD)の特性より劣化することが明らかとなった.しかし,送信側で一次外挿法を用いることで,大きな改善効果が得られることが確認できた.

Performance Evaluation of 2×2 MIMO Space Division Multiplexing Based on Indoor Propagation Measurement
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 87, 9, 1442, 1453, The Institute of Electronics, Information and Communication Engineers, Sep. 2004, [Peer-reviewed]
Japanese, 従来,MIMOシステムに空間分割多重方式を適用させるMIMO-SDMの研究では,送受信アンテナ間のチャネルは独立なレイリーフェージング環境と仮定されることが多く,この仮定のもとでは,受信側での処理により信号ストリームの分離検出が可能となる.本論文では,チャネル間の独立性が崩れる可能性のある,見通し内伝搬路で行った5.2GHz帯での伝搬実験結果から,そのような環境における2×2MIMO-SDMの有効性を検証し,見通しとならない環境における特性との比較を行っている.また,同様の実験を電波暗室でも行い,極めてマルチパス波の少ない環境でのMIMO-SDMの挙動を紹介する.これらの実験の結果,見通し内伝搬環境においても散乱波が存在する場合にはSDM方式が有効であること,見通し外伝搬環境に比べてアンテナ素子の配置等により,特性が大きく変動する傾向にあることが分かった.

Applications of Space Division Multiplexing and Those Performance in a MIMO Channel
OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 87, 9, 1162, 1173, The Institute of Electronics, Information and Communication Engineers, Sep. 2004, [Peer-reviewed]
Japanese, MIMO(Multiple-Input Multiple-Output)チャネル伝送において,複数のアンテナから同時に異なる信号系列を伝送する空間分割多重方式は,限られた周波数帯域で高速伝送を可能とする手法として注目されている.本論文では,各種空間分割多重方式の送受信方式について解説するとともに,送受信アンテナ本数の増加による特性改善効果について計算機シミュレーションにより明らかにする.また,誤り訂正符号化時における特性評価も併せて行う.

Development and evaluation of a smart antenna test bed for wireless LAN
Y Doi, S Nakao, Y Tanaka, T Ohgane, Y Ogawa
IEICE TRANSACTIONS ON ELECTRONICS, E87C, 9, 1449, 1454, Sep. 2004, [Peer-reviewed]
English, Scientific journal

Channel and frequency offset estimation for a MIMO-OFDM system
Y Ogawa, K Nishio, T Nishimura, T Ohgane
VTC2004-FALL: 2004 IEEE 60TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-7, 1523, 1527, 2004, [Peer-reviewed]
English, International conference proceedings

Development and evaluation of the SDMA test bed for PHS in the field
Y Doi, J Kitakado, T Ito, T Miyata, S Nakao, T Ohgane, Y Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E86B, 12, 3433, 3440, Dec. 2003, [Peer-reviewed]
English, Scientific journal

A study on an antenna selection scheme for space-time turbo code for OFDM systems
M Hoshino, M Uesugi, T Ohgane, Y Ogawa, T Nishimura
IEICE TRANSACTIONS ON COMMUNICATIONS, E86B, 12, 3476, 3482, Dec. 2003, [Peer-reviewed]
English, Scientific journal

Signal space whitening MLSE with a multibeam adaptive array
A Hanaki, T Ohgane, Y Ogawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E86B, 9, 2592, 2599, Sep. 2003, [Peer-reviewed]
English, Scientific journal

A MIMO-OFDM system for high-speed transmission
Yasutaka Ogawa, Keisuke Nishio, Toshihiko Nishimura, Takeo Ohgane
IEEE Vehicular Technology Conference, 58, 1, 493, 497, Institute of Electrical and Electronics Engineers Inc., 2003
English, International conference proceedings

A study on channel efficiency for SDMA with an adaptive array
T Suzuki, T Ohgane, Y Ogawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 86, 11, 75, 83, 2003, [Peer-reviewed]
English, Scientific journal

Performance enhancement and compensation of carrier frequency offset using CRA-AA for uplink in SDMA system
Y Kishiyama, T Nishimura, T Ohgane, Y Ogawa, Y Doi
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 86, 5, 81, 91, 2003, [Peer-reviewed]
English, Scientific journal

Realized case of smart antenna in mobile communication systems
Y Doi, J Kitakado, T Ito, T Miyata, S Nakao, T Ohgane, Y Ogawa
2003 IEEE TOPICAL CONFERENCE ON WIRELESS COMMUNICATION TECHNOLOGY, 180, 180, 2003, [Peer-reviewed]
English, International conference proceedings

A MIMO-OFDM system for high-speed transmission
Y Ogawa, K Nishio, T Nishimura, T Ohgane
2003 IEEE 58TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS1-5, PROCEEDINGS, 493, 497, 2003, [Peer-reviewed]
English, International conference proceedings

A study of an antenna selection scheme for Space-Time Turbo codes
M Hoshino, M Uesugi, T Ohgane, Y Ogawa
PIMRC 2003: 14TH IEEE 2003 INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS PROCEEDINGS, VOLS 1-3 2003, 1973, 1977, 2003, [Peer-reviewed]
English, International conference proceedings

A Study on an Adaptive Array Antenna in W-CDMA Downlink
KITAHARA Minako, MIYATANI Tetsuhiko, OGAWA Yasutaka, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 85, 9, 1665, 1668, The Institute of Electronics, Information and Communication Engineers, Sep. 2002, [Peer-reviewed]
Japanese, 高速伝送時のW-CDMAでは干渉が重大な問題となる.下り回線には干渉キャンセラの適用は難しく,他の方式が必要となる.本論文では,下り回線にも適用可能なアダプティブアレーアンテナのウェイト制御法を提案し,干渉除去効果が向上することを報告する.

A Study on Channel Efficiency for SDMA with an Adaptive Array
SUZUKI Tohru, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 85, 3, 346, 353, The Institute of Electronics, Information and Communication Engineers, Mar. 2002, [Peer-reviewed]
Japanese, 近年,チャネルの利用効率を向上させるため,SDMA(Space Division Multiple Access)方式が提案されている.本論文ではアダプティブアレーをセルラシステムに適用し,固定チャネル割当てと動的チャネル割当てについてMMSE基準のウェイト制御を行った場合のSDMA方式の検討を行う.また,従来の呼損率と強制切断率に加え,新たにQoS(Quality of Service)としてISR(Incomplete Service Rate)を定義し特性評価を行っている.更に,SDMA方式による自セル内のユーザ多重度についてランダム割当てを用い考察した.9セル繰返しの固定チャネル割当てにSDMA方式を併用した場合,呼損率3%で2.08倍の容量増加となることがわかった.

High data-rate transmission with Eigenbeam-space division multiplexing (E-SDM) in a MIMO channel　　　　　　　　　　　　　　　
Kazumi Miyashita, Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yasushi Takatori, Keizo Cho
IEEE Vehicular Technology Conference, 56, 3, 1302, 1306, 2002
English, International conference proceedings

Random code selection for a multibeam adaptive array in a slotted ALOHA radio network
K Ito, T Ohgane, Y Ogawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 85, 9, 69, 77, 2002, [Peer-reviewed]
English, Scientific journal

Transmit nullforming for a MIMO/SDMA downlink with receive antenna selection
T Nishimura, Y Takatori, T Ohgane, Y Ogawa, KZ Cho
IEEE 56TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2002, VOLS 1-4, PROCEEDINGS, 190, 194, 2002, [Peer-reviewed]
English, International conference proceedings

High data-rate transmission with eigenbeam-space division multiplexing (E-SDM) in a MIMO channel
K Miyashita, T Nishimura, T Ohgane, Y Ogawa, Y Takatori, K Cho
IEEE 56TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2002, VOLS 1-4, PROCEEDINGS, 1302, 1306, 2002, [Peer-reviewed]
English, International conference proceedings

The SDMA/TDD base station for PHS mobile communication
Y Doi, T Ito, J Kitakado, T Miyata
IEEE 55TH VEHICULAR TECHNOLOGY CONFERENCE, VTC SPRING 2002, VOLS 1-4, PROCEEDINGS, 1074, 1078, 2002, [Peer-reviewed]
English, International conference proceedings

A spatial domain interference canceller using a multistage adaptive array with precise timing estimation
T Nishimura, Y Tanabe, T Ohgane, Y Ogawa, Y Doi, J Kitakado
IEICE TRANSACTIONS ON COMMUNICATIONS, E84B, 7, 1735, 1742, Jul. 2001, [Peer-reviewed]
English, Scientific journal

Advances in adaptive antenna technologies in Japan
Y Ogawa, T Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E84B, 7, 1704, 1712, Jul. 2001, [Peer-reviewed]
English, Scientific journal

Space domain multistage interference canceller for SDMA
T Nishimura, T Ohgane, Y Ogawa, Y Doi, J Kitakado
IEICE TRANSACTIONS ON COMMUNICATIONS, E84B, 3, 377, 382, Mar. 2001, [Peer-reviewed]
English, Scientific journal

Performance Enhancement and Compensation of Carrier Frequency Offset Using CRA-AA for Uplink in SDMA System
KISHIYAMA Yoshihisa, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, DOI Yoshiharu
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 84, 2, 178, 187, The Institute of Electronics, Information and Communication Engineers, Feb. 2001, [Peer-reviewed]
Japanese, 近年, チャネルの利用効率を向上させるためSDMA(Space Division Multiple Access)方式が提案されている.SDMA方式では, 同一チャネルに収容されたすべてのユーザ間で深刻な干渉が生じるため, 基地局でこれらを分離・検出する手法が必要となる.そこで, 本論文では, 上り回線においてチャネル応答推定を行い, その結果を用いて間接的に指向性制御を行うCRA-AA(Channel Response Assisted Adaptive Array)を提案し, MMSE基準のアダプティブアレー, 及び結合推定との特性比較を行った.また, 各ユーザにおいてそれぞれ発生するキャリヤ周波数オフセットを補償する手法についても検討を行った.その結果, CRA-AAが高速フェージングに対する特性, 及びキャリヤ周波数オフセットに対する特性がともに優れていることがわかった.

Transmit diversity technique using space division multiplexing and turbo codes
M Yamashita, T Ohgane, Y Ogawa
ELECTRONICS LETTERS, 37, 3, 184, 185, Feb. 2001, [Peer-reviewed]
English, Scientific journal

Downlink beamforming performance for an SDMA terminal with joint detection
Toshihiko Nishimura, Takeo Ohgane, Yasutaka Ogawa, Yoshiharu Doi, Jun Kitakado
IEEE Vehicular Technology Conference, 3, 54, 1538, 1542, 2001, [Peer-reviewed]
English, Scientific journal

A downlink multiplexing method in TDD packet radio networks with a multibeam adaptive array
Masatsugu Higashinaka, Takeo Ohgane, Yasutaka Ogawa
IEEE Vehicular Technology Conference, 3, 54, 1329, 1333, 2001, [Peer-reviewed]
English, Scientific journal

Adaptive DFE control with differential LMS algorithm
M Hoshino, T Ohgane, Y Ogawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 84, 1, 99, 108, 2001, [Peer-reviewed]
English, Scientific journal

Downlink beamforming performance for an SDMA terminal with joint detection
T Nishimura, T Ohgane, Y Ogawa, Y Doi, J Kitakado
IEEE 54TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2001, VOLS 1-4, PROCEEDINGS, 1538, 1542, 2001, [Peer-reviewed]
English, International conference proceedings

A downlink multiplexing method in TDD packet radio networks with a multibeam adaptive array
M Higashinaka, T Ohgane, Y Ogawa
IEEE 54TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2001, VOLS 1-4, PROCEEDINGS, 1329, 1333, 2001, [Peer-reviewed]
English, International conference proceedings

Basestation adaptive antennas for a high-speed FDD/TDMA system
Y Ogawa, Y Tanabe, T Nishimura, T Ohgane
2001 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-10, CONFERENCE RECORD, 2558, 2562, 2001, [Peer-reviewed]
English, International conference proceedings

Combining techniques for spatial-domain path-diversity using an adaptive array
K Fujishima, Y Tanabe, T Nishimura, Y Ogawa, T Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E83B, 12, 2593, 2599, Dec. 2000, [Peer-reviewed]
English, Scientific journal

High-Resolution Time Delay Estimation of Multipath Signals Using the Genetic Algorithm
ARAKI Hiroshi, OGAWA Yasutaka, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 83, 11, 1645, 1647, The Institute of Electronics, Information and Communication Engineers, Nov. 2000, [Peer-reviewed]
Japanese, 本論文では, 高分解能多重波伝搬遅延時間推定法として多変量を同時に扱う検索に適しているといわれる遺伝的アルゴリズム(GA)を, アナログ量を直接処理できるよう改良した手法を提案する.次に, 計算機シミュレーションの結果から提案手法の有効性を示す.

DOWNLINK NULL STEERING USING CHANNEL ESTIMATION IN A TDD/SDMA SYSTEM
Takeo Ohgane, Yasutaka Ogawa, Yoshihisa Kishiyama, Toshihiko Nishimura
IEICE Proceeding Series, 9, 4A3-2, The Institute of Electronics, Information and Communication Engineers, 22 Aug. 2000
English

A spatial-domain RAKE receiver using a super-resolution technique
Y Tanabe, K Fujishima, Y Ogawa, T Ohgane
IEICE TRANSACTIONS ON COMMUNICATIONS, E83B, 8, 1664, 1670, Aug. 2000, [Peer-reviewed]
English, Scientific journal

Fixed Channel Allocation Method in Mobile Radio Communications Using the Genetic Algorithm
MURAKAMI Homare, OGAWA Yasutaka, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 83, 6, 769, 779, The Institute of Electronics, Information and Communication Engineers, Jun. 2000, [Peer-reviewed]
Japanese, 本論文では, 遺伝的アルゴリズム(GA)を用いた, 移動通信における固定チャネル割当法の提案を行っている.GAは確率的探索手法と呼ばれるものの一つであり, 確率的手法を用いることにより, 少ない計算量で準最適解(近似解)を得ようとする手法である.提案方式では, 通常のGAに対して, 染色体の構造を2次元に拡張している.それによって得られる, スキーマと呼ばれる遺伝子の部分集合に着目し, これらの有用な部分を壊さないように, 交叉(こうさ)及び突然変異と呼ばれる遺伝的操作法を改良して用いている.また, 割当チャネル数を固定化し, 突然変異率の可変最適化を適用し, 更に既知である7セルクラスタ条件により一定数のチャネルを全セルに対して先に分配することで, 更なる計算量の低減を図っている.そこで, これらを組み合わせた手法を, 複数の異なるトラヒックの環境に対して適用させ, 干渉を伴わない固定チャネル割当ての生成を行うことができることを示している.また提案方式がどのような条件に適用できるかを示す.

Random Code Selection for a Multibeam Adaptive Array in a Slotted ALOHA Radio Network
ITO Kuniaki, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 83, 4, 416, 423, The Institute of Electronics, Information and Communication Engineers, Apr. 2000, [Peer-reviewed]
Japanese, 従来, マルチビームアダプティブアレーを用いたスロットアロハ方式では, 到着時間差によるPN符号のずれを用いて衝突パケットの分離検出を行っていた.そこで本論文では, 従来方式と異なり各ユーザが複数のPN符号からランダムに選択することによって, 各ユーザに固有の符号を割り当てなくても衝突パケットを分離検出できる方式を提案する.計算機シミュレーションによるスループット特性の評価を行った結果, 分離条件が符合選択のみの提案手法では, 同一PN符号によるパケットの衝突はあるものの, 到着時間差を設けなくても高いスループットが得られることがわかった.このため, プリアンブル長の増加を抑えることによって, 伝送効率を改善することができる.また, 符号数16, 素子数4の場合スループットが約2.2となり高い改善特性が得られることがわかった.

High-resolution Estimation of Multipath Propagation Based on the 2D-MUSIC Algorithm Using Time-Domain Signals
TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 83, 4, 407, 415, The Institute of Electronics, Information and Communication Engineers, Apr. 2000, [Peer-reviewed]
Japanese, 電磁波の伝搬環境を解明する手法として, MUSICアルゴリズムは高分解能な推定を実現する方式として知られている.本論文では, 送信側と受信側をケーブルでつなぐことなく伝搬環境を推定する手法として, 時間領域の信号にMUSICアルゴリズムを適用する方法を提案する.また, 受信の際にアレーアンテナを用いることにより, 到来方向と伝搬遅延時間を同時に推定する2次元MUSICアルゴリズムの定式化を行う.更に, 計算機シミュレーションにより本手法の分解能特性と推定精度について検討を行い, その結果, 本論文で提案する2次元MUSICアルゴリズムによる推定が, 1次元MUSICアルゴリズムよりも高分解能・高精度に実現できることがわかった.

Spatial domain interference canceler using multistage adaptive array with precise timing estimation　　　　　　　　　　　　　　　
T. Nishimura, Y. Tanabe, T. Ohgane, Y. Ogawa, Y. Doi, J. Kitakado
IEEE Vehicular Technology Conference, 2, 52, 719, 724, 2000
English, International conference proceedings

Cochannel interference cancellation by base station adaptive array in uncorrelated Rayleigh fading channel
Y Katoh, T Ohgane, Y Ogawa, K Itoh
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 83, 5, 97, 106, 2000, [Peer-reviewed]
English, Scientific journal

Signal space whitening MLSE with a multibeam adaptive array
A Hanaki, T Ohgane, Y Ogawa
IEEE VEHICULAR TECHNOLOGY CONFERENCE, FALL 2000, VOLS 1-6, PROCEEDINGS, 406, 411, 2000, [Peer-reviewed]
English, International conference proceedings

Spatial domain interference canceler using multistage adaptive array with precise timing estimation
T Nishimura, Y Tanabe, T Ohgane, Y Ogawa, Y Doi, J Kitakado
IEEE VEHICULAR TECHNOLOGY CONFERENCE, FALL 2000, VOLS 1-6, PROCEEDINGS, 719, 724, 2000, [Peer-reviewed]
English, International conference proceedings

Space domain multistage interference canceler for SDMA
T Nishimura, T Ohgane, Y Ogawa, Y Doi, J Kitakado
2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, 655, 659, 2000, [Peer-reviewed]
English, International conference proceedings

An adaptive antenna for spatial-domain path-diversity using a super-resolution technique
Y Tanabe, K Fujishima, T Nishimura, Y Ogawa, T Ohgane
2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, 1, 5, 2000, [Peer-reviewed]
English, International conference proceedings

Weight estimation for downlink null steering in a TDD/SDMA system
Y Kishiyama, T Nishimura, T Ohgane, Y Ogawa, Y Doi
2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, 346, 350, 2000, [Peer-reviewed]
English, International conference proceedings

A base station adaptive antenna for downlink transmission in a DS-CDMA system
M Kitahara, Y Ogawa, T Ohgane
2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, 710, 715, 2000, [Peer-reviewed]
English, International conference proceedings

A Criterion of Channel Assignment for SDMA with an Adaptive Array
TANAKA Daisuke, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 82, 11, 2133, 2141, The Institute of Electronics, Information and Communication Engineers, 25 Nov. 1999
Japanese, 同一チャネル干渉除去技術として基地局にアダプティブアレーを用いたSDMA方式を検討した.SDMA方式においては,所要の誤り率特性を得られない場合も起こりうるので,チャネルの割当可否を事前に,かつ容易に判断する手法が必要となる.ユーザからの信号が特定の到来方向を有する場合には,アレーの応答ベクトルによって与えられる空間相関を用いる手法が考えられる.本論文では,2ユーザ及び3ユーザにおけるチャネル割当基準を検討した.このとき空間相関値はそれぞれ一つまたは三つ与えられるが,2ユーザの場合は各ユーザの平均SNRと相関値が割当基準となり,3ユーザの場合は各ユーザの平均SNRと三つの相関値の積と2乗和の関係が割当基準となることが明らかとなった.また,3ユーザの場合に孤立セルにおいて呼損率特性を評価した結果,SDMAを用いない場合と比較して収容トラヒックはおよそ3.5倍まで上昇することが明らかとなった.

Adaptive Array for Mobile Radio [IV・Finish] : Estimation of Direction of Arrival (DOA)
OHGANE Takeo, OGAWA Yasutaka
The Journal of the Institute of Electronics, Information, and Communication Engineers, 82, 3, 264, 271, The Institute of Electronics, Information and Communication Engineers, Mar. 1999, [Peer-reviewed]
Japanese

Adaptive Array for Mobile Radio [III] : Applications to Interference Canceling and Multi Path Fading Compensation
OHGANE Takeo, OGAWA Yasutaka
The Journal of the Institute of Electronics, Information, and Communication Engineers, 82, 2, 181, 188, The Institute of Electronics, Information and Communication Engineers, Feb. 1999, [Peer-reviewed]
Japanese

Adaptive Array for Mobile Radio [II] : Algorithm
OHGANE Takeo, OGAWA Yasutaka
The Journal of the Institute of Electronics, Information, and Communication Engineers, 82, 1, 55, 61, The Institute of Electronics, Information and Communication Engineers, Jan. 1999, [Peer-reviewed]
Japanese

A novel cost function for cascaded connection of adaptive array and MLSE
Akihito Haaaki, Takeo Ohgane, Yasutaka Ogawa
IEEE Vehicular Technology Conference, 50, 1, 6, 10, 1999, [Peer-reviewed]
English, International conference proceedings

Weighting factors in spatial-domain path-diversity using an adaptive antenna
Y Ogawa, K Fujishima, T Ohgane
1999 IEEE 49TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-3, 2184, 2188, 1999, [Peer-reviewed]
English, International conference proceedings

Adaptive Array for Mobile Radio [I] : Overview of Adaptive Array in Multipath Channel
OHGANE Takeo, OGAWA Yasutaka
The Journal of the Institute of Electronics, Information, and Communication Engineers, 81, 12, 1254, 1260, The Institute of Electronics, Information and Communication Engineers, Dec. 1998, [Peer-reviewed]
Japanese

A Study on Multiuser Detectable Blind Canceller for DS-CDMA
YAMAZAKI Kenichiro, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers, 81, 11, 1021, 1029, The Institute of Electronics, Information and Communication Engineers, Nov. 1998, [Peer-reviewed]
Japanese, DS-CDMA用ブラインド型マルチユーザ検出器について検討する.本検出器は各ユーザ間の同期がほぼ保たれていると仮定した場合に, 逆拡散後の各ユーザの信号を平均的なシンボルタイミングで同時にサンプリングすることで受信機の構成が簡易なものとできる.最適ウエートは受信信号と各逆拡散符号の相互相関値のみで求められるため, 判定信号や参照信号を必要としないブラインドアルゴリズムが適用できる.また, 受信信号の相関行列が実対称行列となることを利用して, SMI, RLS両アルゴリズムにおいて演算量を約半分に削減できることがわかった.また, 計算機シミュレーションにより, 本方式が簡易かつ良好にマルチユーザ検出できることを明らかにした.

Adaptive DFE Control with Differential LMS Algorithm
HOSHINO Masayuki, OHGANE Takeo, OGAWA Yasutaka
The transactions of the Institute of Electronics, Information and Communication Engineers, 81, 11, 1013, 1020, The Institute of Electronics, Information and Communication Engineers, Nov. 1998, [Peer-reviewed]
Japanese, ディジタル陸上移動通信で高速・高品質伝送を実現するためには, アルゴリズムの簡略化と周波数選択性フェージングへの追従性能を同時に満足しなければならない.本論文では, 判定帰還型等化器を用いる適応アルゴリズムとして, 差分量を導入したLMSアルゴリズムを提案する.差分量の導入により単純マルコフプロセス近似の可能な伝搬路を追従する能力の向上が期待できる.このアルゴリズムを用いて, 簡易な構成となるLMS-DFEを設計し, 計算機シミュレーションにより伝送特性の評価を行った結果, 通常のLMS-DFEと比べて変動への耐久性向上とフロア誤りの半減を確認した.更に, ダイバーシチ合成DFEへの拡張についても検討し, 同様の結果を得た.

A Study on the Performance of Spatial-Domain Path-Diversity Using an Adaptive Array
SASAKI Ryuhei, OGAWA Yasutaka, OHGANE Takeo, ITOH Kiyohiko
The transactions of the Institute of Electronics, Information and Communication Engineers, 81, 9, 855, 862, The Institute of Electronics, Information and Communication Engineers, Sep. 1998, [Peer-reviewed]
Japanese, 高速ディジタル移動通信においては, 遅延時間差の長い多重伝搬波のため特性が劣化する.この多重波信号電力の有効利用とひずみ補償をはかる手段として, 複数のウエートベクトルをもつアダプティブアレーを用いて, 到来する各多重伝搬波を分離し, 遅延時間を一致させた後合成する空間領域パスダイバーシチが提案されている.多重波のなかには近接して到来する伝搬波が含まれている場合もあるため, 特性が劣化することがある.本論文では, この改善方法として, 多重波信号電力とアダプティブアレーの誤差電力を考慮した荷重合成法を提案した.その結果, 劣化要因であった到来角度が非常に近接した伝搬環境において従来の等利得合成と比較して提案方式は, 大幅にBER特性を改善できることが明らかになった.

ISI and CCI canceller with preselecting adaptive array and cascaded equalizer in digital mobile radio
Y Doi, T Ohgane, Y Karasawa
IEICE TRANSACTIONS ON COMMUNICATIONS, E81B, 3, 674, 682, Mar. 1998, [Peer-reviewed]
English, Scientific journal

Down-link performance of interference canceller combining path pre-selecting adaptive array and cascaded equalizer　　　　　　　　　　　　　　　
Yoshiharu Doi, Takeo Ohgane, Yoshio Karasawa
IEEE Vehicular Technology Conference, 3, 2512, 2516, IEEE, 1998
English, International conference proceedings

Cochannel Interference Cancellation by Base Station Adaptive Array in Uncorrellated Rayleigh Fading Channel
KATOH Yoshihisa, OHGANE Takeo, OGAWA Yasutaka, ITOH Kiyohiko
The transactions of the Institute of Electronics, Information and Communication Engineers, 81, 1, 1, 9, The Institute of Electronics, Information and Communication Engineers, Jan. 1998, [Peer-reviewed]
Japanese, 低アンテナ高基地局, すなわち各アンテナ素子に生じるフェージングがそれぞれ無相関となる場合について, アダプティブアレーによる干渉除去特性を検討した。本論文では特にアンテナ本数, 干渉波数が多い場合について着目し, SINR特性, BER特性の評価を行った。SINR特性の検討により, 平均SNRが大きい場合には, ダイバーシチ利得がほとんど得られないのに対して, 平均SNRが小さい場合には, ダイバーシチ利得が大きくなることが明らかになった。BER特性においては, アンテナ本数が7本程度までは, ほぼアンテナ本数増加による利得のみとなった。しかし, 10本以上になると若干ながら余剰自由度によりダイバーシチ利得が得られることがわかった。フェージング変動(上り回線, 下り回線)による影響の検討では, 上り回線において, RLS法, SMI補間法では規格化ドップラー周波数が1×10<-4>以下では劣化が少なくほぼ追従できているという結果が得られた。下り回線においては, SMI1次外挿法, RLS1次外挿法, 双方とも規格化ドップラー周波数が1×10<-4>以下ではフロア誤りが1×10<-2>以下となり, ある程度適用可能であることがわかった。

An adaptive antenna for spatial-domain path-diversity
Y Ogawa, R Sasaki, T Ohgane, K Itoh
48TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-3, 544, 547, 1998, [Peer-reviewed]
English, International conference proceedings

Random preamble code selection for slotted ALOHA radio network with a multibeam adaptive array
T Ohgane, K Ito, Y Ogawa
GLOBECOM 98: IEEE GLOBECOM 1998 - CONFERENCE RECORD, VOLS 1-6, 3193, 3198, 1998, [Peer-reviewed]
English, International conference proceedings

Down-link performance of interference canceller combining path pre-selecting adaptive array and cascaded equalizer
Y Doi, T Ohgane, Y Karasawa
48TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-3, 2512, 2516, 1998, [Peer-reviewed]
English, International conference proceedings

An adaptive antenna for a multipath propagation environment
Y Ogawa, R Sasaki, T Ohgane, K Itoh
ICC 98 - 1998 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS VOLS 1-3, 1345, 1349, 1998, [Peer-reviewed]
English, International conference proceedings

A study on a channel allocation scheme with an adaptive array in SDMA
T Ohgane, Y Ogawa, K Itoh
1997 IEEE 47TH VEHICULAR TECHNOLOGY CONFERENCE PROCEEDINGS, VOLS 1-3, 725, 729, 1997, [Peer-reviewed]
English, International conference proceedings

Adaptive antennas for future mobile radio
Y Ogawa, T Ohgane
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E79A, 7, 961, 967, Jul. 1996, [Peer-reviewed]
English, Scientific journal

ISI and CCI canceller combining the adaptive array antennas and the Viterbi equalizer in a digital mobile radio
Y Doi, T Ohgane, E Ogawa
1996 IEEE 46TH VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, 81, 85, 1996, [Peer-reviewed]
English, International conference proceedings

Multipath time delay estimation by super-resolution PN correlation method　　　　　　　　　　　　　　　
Yoshiharu Doi, Takeo Ohgane
ICAP 1995, 249, 252, Apr. 1995, [Peer-reviewed]
English

SPECTRAL EFFICIENCY IMPROVEMENT BY BASE STATION ANTENNA PATTERN CONTROL FOR LAND MOBILE CELLULAR-SYSTEMS
T OHGANE
IEICE TRANSACTIONS ON COMMUNICATIONS, E77B, 5, 598, 605, May 1994, [Peer-reviewed]
English, Scientific journal

APPLICATION OF ADAPTIVE ARRAY ANTENNAS TO RADIO-COMMUNICATIONS
M MIZUNO, T OHGANE
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 77, 2, 48, 59, Feb. 1994, [Peer-reviewed]
English, Scientific journal

SPECTRAL EFFICIENCY EVALUATION OF ADAPTIVE ARRAY BASE STATION FOR LAND MOBILE CELLULAR-SYSTEMS
T OHGANE
VTC 1994 - 1994 IEEE 44TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-3, 1470, 1474, 1994, [Peer-reviewed]
English, International conference proceedings

BER PERFORMANCE OF CMA ADAPTIVE ARRAY FOR HIGH-SPEED GMSK MOBILE COMMUNICATION - A DESCRIPTION OF MEASUREMENTS IN CENTRAL TOKYO
T OHGANE, N MATSUZAWA, T SHIMURA, M MIZUNO, H SASAOKA
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, 42, 4, 484, 490, Nov. 1993, [Peer-reviewed]
English, Scientific journal

AN IMPLEMENTATION OF A CMA ADAPTIVE ARRAY FOR HIGH-SPEED GMSK TRANSMISSION IN MOBILE COMMUNICATIONS
T OHGANE, T SHIMURA, N MATSUZAWA, H SASAOKA
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, 42, 3, 282, 288, Aug. 1993, [Peer-reviewed]
English, Scientific journal

An adaptive antenna for spatial-domain path-diversity　　　　　　　　　　　　　　　
Y. Ogawa, R. Sasaki, T. Ohgane, K. Itoh
IEEE VTC 1998, 544, 547, May 1993, [Peer-reviewed]
English

SPECTRAL EFFICIENCY IMPROVEMENT BY BASE STATION ANTENNA PATTERN CONTROL FOR LAND MOBILE CELLULAR-SYSTEMS
T OHGANE
GLOBECOM '93 COMMUNICATIONS FOR A CHANGING WORLD, CONFERENCE RECORD, 913, 917, 1993, [Peer-reviewed]
English, International conference proceedings

BER Performance of CMA Adaptive Array for a High Speed GMSK Transmission - A Description of Measurements in Central Tokyo
OHGANE Takeo, SASAOKA Hideichi, MATSUZAWA Naoto, SHIMURA Takanori
The Transactions of the Institute of Electronics,Information and Communication Engineers. B-II, 75, 11, 797, 805, 電子情報通信学会通信ソサイエティ, Nov. 1992, [Peer-reviewed]
Japanese

Application of Adaptive Array Antennas to Radio Communications
MIZUNO Mitsuhiko, OHGANE Takeo
The Transactions of the Institute of Electronics,Information and Communication Engineers. B-II, 75, 11, 733, 741, 電子情報通信学会通信ソサイエティ, Nov. 1992, [Peer-reviewed]
Japanese

A NOVEL DUAL ANTENNA MEASUREMENT OF THE ANGULAR-DISTRIBUTION OF RECEIVED WAVES IN THE MOBILE RADIO ENVIRONMENT AS A FUNCTION OF POSITION AND DELAY TIME
HJ THOMAS, T OHGANE, M MIZUNO
VEHICULAR TECHNOLOGY SOCIETY 42ND VTS CONFERENCE - FRONTIERS OF TECHNOLOGY : FROM PIONEERS TO THE 21ST CENTURY, VOLS 1 AND 2, 546, 549, 1992, [Peer-reviewed]
English, International conference proceedings

DEVELOPMENT OF MULTIPATH MEASUREMENT AND SIMULATION EQUIPMENT FOR WIDE-BAND MOBILE RADIO
E MORIYAMA, M MIZUNO, T IWAMA, T OHGANE, H RYUKO, S SEKIZAWA
VEHICULAR TECHNOLOGY SOCIETY 42ND VTS CONFERENCE - FRONTIERS OF TECHNOLOGY : FROM PIONEERS TO THE 21ST CENTURY, VOLS 1 AND 2, 536, 539, 1992, [Peer-reviewed]
English, International conference proceedings

BER PERFORMANCE OF CMA ADAPTIVE ARRAY FOR A GMSK TDMA SYSTEM - A DESCRIPTION OF MEASUREMENTS IN CENTRAL TOKYO
T OHGANE, H SASAOKA, N MATSUZAWA, T SHIMURA
VEHICULAR TECHNOLOGY SOCIETY 42ND VTS CONFERENCE - FRONTIERS OF TECHNOLOGY : FROM PIONEERS TO THE 21ST CENTURY, VOLS 1 AND 2, 1012, 1017, 1992, [Peer-reviewed]
English, International conference proceedings

Characteristics of CMA adaptive array for selective fading compensation in digital land mobile radio communications
Takeo Ohgane
Electronics and Communications in Japan (Part I: Communications), 74, 9, 43, 53, 1991, [Peer-reviewed]
English, Scientific journal

A DEVELOPMENT OF GMSK/TDMA SYSTEM WITH CMA ADAPTIVE ARRAY FOR LAND MOBILE COMMUNICATIONS
T OHGANE, H SASAOKA, N MATSUZAWA, K TAKEDA, T SHIMURA
41ST IEEE VEHICULAR TECHNOLOGY CONFERENCE, 172, 177, 1991, [Peer-reviewed]
English, International conference proceedings

Characteristics of CMA adaptive array for selective fading compensation in digital land mobile communications
Takeo Ohgane
IEICE Transactions on Communications, B-II, 73, 10, p489, 497, 電子情報通信学会通信ソサイエティ, Oct. 1990, [Peer-reviewed]
Japanese

UHF urban and suburban multipath propagation characteristics in wideband mobile radio communications
OHGANE T
The Transactions of the Institute of Electronics,Information and Communication Engineers. B-II, 72, 2, p63, 71, 電子情報通信学会通信ソサイエティ, Feb. 1989, [Peer-reviewed]
Japanese

RECTENNA COMPOSED OF A CIRCULAR MICROSTRIP ANTENNA
K ITOH, T OHGANE, Y OGAWA
SPACE POWER, 6, 3, 193, 198, 1986, [Peer-reviewed]
English, Scientific journal

FUNDAMENTAL-STUDY ON SPS RECTENNA PRINTED ON A SHEET OF COPPER CLAD LAMINATE
K ITOH, Y AKIBA, T OHGANE, Y OGAWA
SPACE SOLAR POWER REVIEW, 5, 2, 149, 162, 1985, [Peer-reviewed]
English, Scientific journal

Proposal of an Evaluation Method for Sub-THz-Band MIMO Spatial Multiplexing Considering Near-Field Propagation Characteristics
木元大聖, 西村寿彦, 小川恭孝, 須山聡, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 125, 88(RCS2025 31-73), 2025

Comparative Study of Channel Prediction Methods Using Compressed Sensing in Sub-THz-Band Communications
牛田永真菜, 西村寿彦, 小川恭孝, 須山聡, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 125, 88(RCS2025 31-73), 2025

Performance Evaluation of OAM Mode Generation and Multiplexing Using Uniform Planar Array Antennas
村田雷蔵, 西村寿彦, 大鐘武雄, 内田大輔, 谷口健太郎, 電子情報通信学会技術研究報告(Web), 125, 88(RCS2025 31-73), 2025

Performance Comparison of Recent MIMO Signal Detection Methods-MCMC, Langevin, and Deep Unfolding Approaches-
萩原淳一郎, 西村寿彦, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 125, 163(RCS2025 98-122), 2025

Optimization of Scale Parameter in Vector Perturbation Method Using Monte Carlo Method for Large-Scale MIMO
角田俊介, 萩原淳一郎, 西村寿彦, 小川恭孝, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2025, 2025

An Evaluation of Communication Quality and Line-of-Sight Impact on LoRa Wireless Communication Using Radio Measurement Vehicle in Sapporo Suburbs
石崎結敦, 國井京太朗, 筒井弘, 大鐘武雄, 映像情報メディア学会技術報告(Web), 48, 23(BCT2024 51-59), 2024

A STUDY ON THE PRACTICE OF DX RECURRENT EDUCATION PROGRAM FOR WORKING PEOPLE IN INFRASTRUCTURE FIELD
堀江進, 中前茂之, 野口渉, 大和尚記, LI Guang, 筒井弘, 大鐘武雄, 土木学会論文集(Web), 80, 23, 2024

Considerations on Computational Complexity Reduction in Channel Prediction Based on Multipath Separation for Sub-THz-Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 123, 434(RCS2023 250-294), 2024

Study on IRS Control Using Vision-Assisted Beam Management in Sub-Terahertz-Band Communications
小林龍平, 西村寿彦, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 124, 84(RCS2024 28-83), 2024

Characterization of Sub-THz-Band MIMO Spatial Multiplexing With Channel Estimation Errors
濱田直輝, 西村寿彦, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 124, 84(RCS2024 28-83), 2024

Study on OAM mode multiplexing transmission using uniform square array
西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会大会講演論文集(CD-ROM), 2024, 2024

Performance Evaluation of Loose Beamforming in the Presence of NLOS Areas
林優太, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2024, 2024

A Study on Nonlinear Precoding Methods in Massive MIMO~Improvement of VP method using MCMC and comparison with THP method~
角田俊介, 萩原淳一郎, 西村寿彦, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 124, 166(RCS2024 116-132), 2024

Study on Initial Solutions of Direct-Binary Search for Loose Beam Forming
谷部遼馬, 西村寿彦, 小川恭孝, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2024, 2024

DOA Estimation Improvement Through Angle-Range-Reduced DNNs Specialized in Narrow DOA Range
安藤ダニエル明, 西村寿彦, 佐藤孝憲, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告(Web), 123, 434(RCS2023 250-294), 2024

A Fundamental Study on Decoding Short Length Polar Codes by Deep Learning
熊木礼於奈, 筒井弘, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

An Evaluation of Speech Segment Extraction Method Using Fundamental Frequency Estimation for Video Conferencing Recordings Automatic Editing System
望月桂太, 筒井弘, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2023, 2023

An Investigation of Temporal Variations in LoRa Modulation-based Communication Performance
齊藤優希, 國井京太朗, 筒井弘, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2023, 2023

Investigating the Impact of LDPC Codes on LoRa Modulation Communication Performance
國井京太朗, 筒井弘, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2023, 2023

An Evaluation of Neural Network Parameters for Decoding (8,4) and (16,8) Polar Codes
熊木礼於奈, 筒井弘, 大鐘武雄, 映像情報メディア学会技術報告(Web), 47, 21(BCT2023 49-66), 2023

Study on Weight Generation for Loose Beamforming with Quantum-inspired Tabu Search
林優太, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2023, 2023

A Study on Performance Improvement of Stochastic MIMO Signal Detection Using Variational Bayesian Methods
阿隅大輝, 角田俊介, 萩原淳一郎, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

Study on IRS Control Based on Beamforming for Sub-Terahertz Band Communications
田所柊人, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

Study on Computational Complexity Reduction in Channel Prediction for Sub-THz Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

Characteristics Analysis of Direction of Arrival Estimation with Compressed Sensing Using Grid Shifts
國本周大, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

Impact of Channel Estimation Error on Antenna Selection Using Simulated Annealing for Distributed MIMO Systems
西村健斗, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 355(IT2022 29-67), 2023

Channel Prediction Based on Multipath Delay Estimation for Sub-Terahertz-Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会論文誌 B(Web), J106-B, 6, 2023

Direct-Binary Search Leveraged Loose Beam Forming in Massive MIMO Systems
林優太, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2023, 2023

Considerations on Subarray Beam Control for Sub-Terahertz MIMO Spatial Multiplexing
濱田直輝, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2023, 2023

Characteristic Comparison of UCA and Square Array on OAM Mode Multiplexing
釜谷俊輝, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会大会講演論文集(CD-ROM), 2023, 2023

A Study on Vector Perturbation Method using MCMC in Massive MIMO
角田俊介, 萩原淳一郎, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 123, 76(RCS2023 28-78), 2023

Study on Characteristic Improvement of Direct-Binary Search Leveraged Loose Beam Forming in Massive MIMO Systems
林優太, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 123, 76(RCS2023 28-78), 2023

Study on Subarray Beam Control for Sub-Terahertz-Band MIMO Spatial Multiplexing
濱田直輝, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 123, 76(RCS2023 28-78), 2023

An Evaluation of the Effects of a Time-varying Environment on the LoRa Modulation-based Communication Performance
國井京太朗, 筒井弘, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2022, 2022

Application of Deep Learning to Logic Functions as a Preliminary Trial of Polar Code Decoder Based on Machine Learning
熊木礼於奈, 筒井弘, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2022, 2022

Fundamental Study of OAM Mode Multiplexing with Square Array
釡谷俊輝, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会大会講演論文集(CD-ROM), 2022, 2022

Spatial Signal Processing in Sub-Terahertz-Band Indoor Radio Communications
小川恭孝, 西村寿彦, 佐藤孝憲, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 235(RCS2022 128-154), 2022

A Study on Channel Prediction Based on Multipath Separation for Sub-Terahertz-Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 235(RCS2022 128-154), 2022

Study on Transmit Weight Generation for Loose Beam Forming
林優太, 西村寿彦, 佐藤孝憲, 萩原淳一郎, 小川恭孝, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2022, 2022

Study on Delay-Domain Multipath Separation in Sub-Terahertz-Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2022, 2022

Accuracy Improvement in DOA Estimation with Deep Learning
KASE Yuya, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, SATO Takanori, KISHIYAMA Yoshihisa, IEICE Transactions on Communications (Web), E105.B, 5, 2022

A Study on Signal Detection Using L-BFGS Method in Massive MIMO
春日由紀子, 萩原淳一郎, 西村寿彦, 佐藤孝憲, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2022, 2022

Quantum Annealing Leveraged Loose Beamforming in Massive MU-MIMO Systems
大塚達樹, 西村寿彦, 大鐘武雄, 佐藤孝憲, 萩原淳一郎, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2022, 2022

Fundamental Considerations on Channel Prediction Based on Multipath Delay and Angle-of-Arrival Estimation for Sub-Terahertz Band Communications
望月大瑚, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 73(RCS2022 24-67), 2022

Comparison of Performance and Complexity for different Search Methods in Stochastic MIMO Signal Detection
阿隅大輝, 春日由紀子, 松村和士, 萩原淳一郎, 西村寿彦, 佐藤孝憲, 小川恭孝, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 73(RCS2022 24-67), 2022

Direction of Arrival Estimation with Compressed Sensing Using Grid Shifts
國本周大, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 73(RCS2022 24-67), 2022

Considerations on IRS Control based on Beamforming for Sub-Terahertz Band Communications
田所柊人, 西村寿彦, 佐藤孝憲, 小川恭孝, 萩原淳一郎, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 73(RCS2022 24-67), 2022

A study on model parameters for MIMO signal detection using learned AMP
三好茉莉, 西村寿彦, 佐藤孝憲, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告(Web), 122, 73(RCS2022 24-67), 2022

Spatial-Domain Signal Processing in Sub-Terahertz Communications
小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会技術研究報告(Web), 122, 117(EMT2022 7-43), 2022

Studies on Sub-Terahertz MIMO Spatial Multiplexing in an Indoor Propagation Environment
宇津野太一, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 121, 327(IT2021 28-82), 2022

Study on compensation for axis misalignment of UCA with multiple UCAs
櫻谷信彦, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会技術研究報告(Web), 121, 327(IT2021 28-82), 2022

Considerations on Accuracy Improvement in Close DOA Estimation with Deep Learning
加瀬裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 佐藤孝憲, 岸山祥久, 電子情報通信学会技術研究報告(Web), 121, 103, 98, 103, Jul. 2021

A Study on the Behavior of LLR Messages in Damped GaBP for Large-scale Signal Detection under a Correlated Channel
安藤ダニエル明, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 121, 72, 97, 102, Jun. 2021

A basic study on signal detection using learned approximate message passing
三好茉莉, 辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 121, 72, 13, 18, Jun. 2021

A Comparison of Variational Bayesian and Expectation Propagation Methods for Massive MIMO Signal Detection
阿隅大輝, 萩原淳一郎, 西村寿彦, 大鐘武雄, 小川恭孝, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 121, 72, 7, 12, Jun. 2021

Considerations on Computational Complexity Reduction in Channel Prediction Based on Multipath Separation
望月大瑚, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 121, 72, 1, 6, Jun. 2021

Wireless Communications Merging with Photonics
西村 寿彦, 佐藤 孝憲, 小川 恭孝, 大鐘 武雄, 電子情報通信学会誌 = The journal of the Institute of Electronics, Information and Communication Engineers, 104, 5, 485, 489, May 2021
電子情報通信学会, Japanese

A Study on Downlink Channel Estimation Based on Multipath Separation in a Wideband FDD System
登坂紫織, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告(Web), 120, 404, 267, 272, Mar. 2021

Compensation for axis misalignment of UCA with OAM beam control
櫻谷信彦, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会技術研究報告(Web), 120, 404, 261, 266, Mar. 2021

A Study of Antenna and UE Selection for Distributed Massive MIMO Systems
西村健斗, 大鐘武雄, 西村寿彦, 萩原淳一郎, 佐藤孝憲, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2021, 2021

A Study on Small Scale Signal Detection Using Learned Approximate Message Passing
辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会大会講演論文集(CD-ROM), 2021, 2021

Fundamental Studies on Beam Search of a 2-Dimensional Array in the Terahertz Band
宇津野太一, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会大会講演論文集(CD-ROM), 2021, 2021

Performance Evaluation of Loose Beamforming for Different Receiver Numbers
大塚達樹, 西村寿彦, 大鐘武雄, 佐藤孝憲, 萩原淳一郎, 小川恭孝, 電子情報通信学会技術研究報告(Web), 120, 322, 75, 80, Jan. 2021

大規模MIMOにおけるハミルトニアンモンテカルロ法を用いた信号検出特性の改善　　　　　　　　　　　　　　　
松村和士, 萩原淳一郎, 西村寿彦, 大鐘武雄, 小川恭孝, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 298, 7, 12, Dec. 2020

Considerations on Accuracy Improvement in DOA Estimation Using Deep Learning
加瀬裕也, 佐藤孝憲, 西村寿彦, 大鐘武雄, 小川恭孝, 来山大祐, 岸山祥久, 電子情報通信学会技術研究報告(Web), 120, 89, 61, 66, Jul. 2020

ガウス確率伝搬法におけるLLRの挙動に関する検討　　　　　　　　　　　　　　　
安藤ダニエル明, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 74, 97, 102, Jun. 2020

Massive MIMOにおけるマルコフ連鎖モンテカルロ法を用いた信号検出に関する研究　　　　　　　　　　　　　　　
松村和士, 萩原淳一郎, 西村寿彦, 大鐘武雄, 小川恭孝, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 74, 91, 95, Jun. 2020

差分進化を用いた簡易ビーム形成に関する検討　　　　　　　　　　　　　　　
大塚達樹, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 74, 67, 72, Jun. 2020

OAM多重伝送におけるアレーの設置誤差による特性劣化の改善　　　　　　　　　　　　　　　
櫻谷信彦, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会技術研究報告, 120, 74, 61, 66, Jun. 2020

LoRaWAN端末を用いた900MHz帯距離減衰特性の測定試験　　　　　　　　　　　　　　　
董 博文, 辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 74, 175, 179, Jun. 2020

近似メッセージ伝搬法による大規模MIMO信号検出に関する検討　　　　　　　　　　　　　　　
辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会技術研究報告, 120, 74, 181, 186, Jun. 2020

A Study on Small Scale Signal Detection Using Approximate Message Passing
辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2020, 2020

A Study on Wideband FDD Downlink Channel Estimation Using Compressed Sensing
登坂紫織, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2020, 2020

Performance Evaluation of Beam Shapes in a Two-Step-Precoded Massive MIMO System
YAMAMOTO Jumpei, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, TAKEDA Daiki, KISHIYAMA Yoshihisa, IEICE Transactions on Communications (Web), E103.B, 6, 2020

Fundamental Trial on DOA Estimation with Deep Learning
KASE Yuya, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, KITAYAMA Daisuke, KISHIYAMA Yoshihisa, IEICE Transactions on Communications (Web), E103.B, 10, 2020

Testing Different DNN Configurations in DOA Estimation Using Deep Learning
加瀬裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 来山大祐, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2020, 2020

Fundamental Studies on Phased Array Beam Control in the Terahertz Band
宇津野太一, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 佐藤孝憲, 電子情報通信学会大会講演論文集(CD-ROM), 2020, 2020

OAMモード多重伝送における多重UCAを用いた特性改善に関する検討　　　　　　　　　　　　　　　
山本綾乃, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会技術研究報告, 119, 296, 55, 60, Nov. 2019

大規模MIMOにおけるノード選択付き近似メッセージ伝搬法による信号検出　　　　　　　　　　　　　　　
辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 296, 43, 47, Nov. 2019

スパースモデリングを用いた到来方向推定 (Invited Lecture)　　　　　　　　　　　　　　　
西村寿彦, 中都正義, 大鐘武雄, 小川恭孝, 革新的無線通信技術に関する横断型研究会 (MIKA), Oct. 2019, [Invited]

大規模SCMAシステムにおけるCRCによる特性改善に関する一検討　　　　　　　　　　　　　　　
李仁杰, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 176, 7, 12, Aug. 2019

深層学習を用いた近接波の到来方向推定の検討—A Study on Close DOA Estimation with Deep Learning—高信頼制御通信
加瀬 裕也, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 来山 大祐, 岸山 祥久, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 119, 106, 133, 138, Jul. 2019
電子情報通信学会, Japanese

送信ダイバーシチを適用したFSK用狭帯域パイロットレス同期検波方式　　　　　　　　　　　　　　　
山口歌奈子, 東中雅嗣, 佐野裕康, 岡村敦, 大鐘武雄, 西村寿彦, 電子情報通信学会技術研究報告, 119, 108, 211, 216, Jul. 2019

深層学習を用いた近接波の到来方向推定の検討　　　　　　　　　　　　　　　
加瀬裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 来山大祐, 岸山祥久, 電子情報通信学会技術研究報告, 119, 108, 155, 160, Jul. 2019

IDMAにおけるガウス確率伝搬法とCRCを利用した信号検出の検討　　　　　　　　　　　　　　　
河端航, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会技術研究報告, 119, 90, 339, 345, Jun. 2019

ガウス確率伝搬法等繰り返し手法を用いた多数信号検出特性 (Invited Talk)　　　　　　　　　　　　　　　
大鐘武雄, 電子情報通信学会技術研究報告, 119, 90, 259, 259, Jun. 2019, [Invited]

深層学習を用いたチャネル推定に関する基礎的研究　　　　　　　　　　　　　　　
中島亮太, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 90, 37, 42, Jun. 2019

到来方向推定における圧縮センシングアルゴリズムの比較検討　　　　　　　　　　　　　　　
中都正義, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 90, 31, 35, Jun. 2019

屋内環境での大規模MIMO分散アンテナシステムにおけるアンテナ選択に関するスループット評価　　　　　　　　　　　　　　　
島屋早希, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 90, 25, 29, Jun. 2019

インパルス応答推定に基づくFDDシステムの下り回線チャネル推定に関する基礎的検討　　　　　　　　　　　　　　　
登坂紫織, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 90, 19, 24, Jun. 2019

LoRaWAN端末を用いた900MHz帯室内距離減衰特性の測定　　　　　　　　　　　　　　　
辻本若葉, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 119, 90, 13, 18, Jun. 2019

深層学習を用いた到来方向推定法の検討　　　　　　　　　　　　　　　
加瀬裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 来山大祐, 岸山祥久, 電子情報通信学会技術研究報告, 119, 8, 79, 84, Apr. 2019

圧縮センシングを用いた2波の到来方向推定の基礎的検討
中都正義, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2019, 2019

雑音を考慮したマルチパスの遅延推定に基づくチャネル予測
高野裕太, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

遅延推定に基づくマルチパス分離によるチャネル予測に関する考察
高野裕太, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

敵対的生成ネットワークを用いたチャネル推定に関する基礎的研究
中島亮太, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

MIMO SC-FDEにおける受信ウェイト行列の演算量削減手法の評価
齋藤剣聖, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

重畳型16QAMを用いた大規模MIMOのDAMPによる信号検出
渡部泰成, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

16点SCMA大規模システムのガウス確率伝搬法による信号検出特性の評価
LI Renjie, 大鐘武雄, 西村寿彦, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

マルチパス通信路のインパルス応答を用いたFDDシステムの下り回線チャネル推定に関する基礎的検討
登坂紫織, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

基地局アンテナアレーの分散化とプリコーディングの関係について
鈴木裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

屋内環境における大規模MIMO分散アンテナシステムのアンテナ選択に関する検討
島屋早希, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

Polar符号化伝送におけるSSCL復号とGaBPを用いた繰り返し適応等化に関する検討
福田健太郎, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

深層学習を用いた到来方向推定の検討
加瀬裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 来山大祐, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2019, 2019

遅延時間推定に基づくマルチパス分離によるチャネル予測に関する検討　　　　　　　　　　　　　　　
高野裕太, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 435, 13, 18, Jan. 2019

インタリーブ分割多元接続におけるガウス確率伝搬法を用いた大規模信号検出に関する検討　　　　　　　　　　　　　　　
河端航, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会技術研究報告, 118, 372, 113, 118, Dec. 2018

MIMO SC-FDEにおける受信ウェイト行列の演算量削減に関する検討　　　　　　　　　　　　　　　
齋藤剣聖, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 372, 25, 30, Dec. 2018

アレー信号処理とその解法アルゴリズムの基礎 (Tutorial Lecture)　　　　　　　　　　　　　　　
西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会技術研究報告, 118, 217, 31, 36, Sep. 2018, [Invited]

A Fundamental Study on Direction of Arrival Estimation with Deep Learning
加瀬 裕也, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 118, 125, 51, 55, 11 Jul. 2018
電子情報通信学会, Japanese

GaBPを用いた大規模SCMA信号分離に関する基礎的検討　　　　　　　　　　　　　　　
李仁杰, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 125, 237, 242, Jul. 2018

Massive MIMO SC-FDEにおける受信ウェイト行列の演算量削減に関する検討　　　　　　　　　　　　　　　
齋藤剣聖, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 101, 261, 266, Jun. 2018

大規模MIMOにおけるGaBPを用いた重畳型16QAM信号検出に関する検討　　　　　　　　　　　　　　　
渡部泰成, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 101, 255, 260, Jun. 2018

異なる伝搬環境におけるOAMモード多重伝送の特性比較　　　　　　　　　　　　　　　
山本綾乃, 西村寿彦, 大鐘武雄, 旦代智哉, 内田大輔, 電子情報通信学会技術研究報告, 118, 101, 201, 206, Jun. 2018

マルチユーザ大規模MIMOシステムにおける遺伝的アルゴリズムを用いた簡易ビーム形成の特性評価　　　　　　　　　　　　　　　
中村駿太, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 101, 101, 106, Jun. 2018

インターリーブ分割多元接続における確率伝搬法を用いた信号検出に関する検討　　　　　　　　　　　　　　　
河端航, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会技術研究報告, 118, 101, 89, 94, Jun. 2018

確率伝搬法を用いた重畳変調信号検出に関する基礎的検討　　　　　　　　　　　　　　　
福田健太郎, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会技術研究報告, 118, 101, 85, 88, Jun. 2018

A Study on Channel Equalization with Belief Propagation in Polar-Coded Single Carrier Transmission
木原 光太郎, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 456, 25, 29, 28 Feb. 2018
電子情報通信学会, Japanese

Considerations on a MIMO Channel Prediction Scheme Using Multipath Separation in Delay, Departure Angle, and Arrival Angle Domains
奥村 香菜子, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 456, 179, 184, 28 Feb. 2018
電子情報通信学会, Japanese

マルチユーザ大規模MIMOシステムにおける簡易ビーム形成のための最適なアンテナ選択方法に関する検討　　　　　　　　　　　　　　　
井上航一, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会技術研究報告, 117, 456, 31, 36, Feb. 2018

Performance evaluation on beam shapes and number of selected beams in a massive MIMO system
山本 順平, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 岸山 祥久, 武田 大樹, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 396, 125, 130, 22 Jan. 2018
電子情報通信学会, Japanese

圧縮センシングを用いたマルチバンド信号の到来方向推定におけるバンド数に関する検討
星川豊希, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

MIMO SC-FDEにおける受信ウェイト補間法の評価
齋藤剣聖, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

遮蔽物のある屋内環境のマルチユーザ大規模MIMOシステムにおける基地局アンテナサブアレーの配置に関する検討
鈴木裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

大規模MU-MIMOシステムにおける簡易ビーム形成の特性改善に関する検討
中村駿太, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

マルチパスの遅延時間推定に基づくチャネル予測に関する検討
高野裕太, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

異なる振幅を有するマルチバンド信号に対する圧縮センシングを用いた到来方向推定に関する検討
星川豊希, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

大規模MIMO SC-FDEにおける受信ウェイト行列の演算量削減手法の比較
齋藤剣聖, 小川恭孝, 西村寿彦, 大鐘武雄, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

屋内環境のマルチユーザ大規模MIMOシステムにおける基地局アンテナサブアレーの配置および素子配列に関する検討
鈴木裕也, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

LLR上限設定を行ったGaBP検出における重畳型16QAM不均一配置の最適化に関する検討
渡部泰成, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

重畳変調信号の重畳数とGaBP検出特性に関する評価
福田健太郎, 西村寿彦, 大鐘武雄, 小川恭孝, 萩原淳一郎, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

大規模MIMOにおけるビーム選択法とビーム選択数に関する特性評価
山本順平, 西村寿彦, 大鐘武雄, 小川恭孝, 武田大樹, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2018, 2018

確率伝搬法による多次元信号検出 (Invited Talk)　　　　　　　　　　　　　　　
大鐘武雄, 西村寿彦, 小川恭孝, 電子情報通信学会技術研究報告, 117, 395, 175, 175, Jan. 2018, [Invited]

Considerations on Computational Complexity Reduction Using Receive Matrix Interpolation in a MIMO SC-FDE System
齋藤 剣聖, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 352, 101, 106, 14 Dec. 2017
電子情報通信学会, Japanese

Accuracy Evaluation of Compressed Sensing Algorithms for DOA Estimation of Multiband Signals
星川 豊希, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 283, 161, 165, 08 Nov. 2017
電子情報通信学会, Japanese

Quasi-upper Bound Evaluation of Multiuser Massive MIMO System by Loose Beam Forming
井上 航一, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 284, 117, 122, 08 Nov. 2017
電子情報通信学会, Japanese

A Study on m-QAM Signal Detection Using Belief Propagation in a Massive MIMO System
渡部 泰成, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 246, 19, 24, 19 Oct. 2017
電子情報通信学会, Japanese

Considerations on a Channel Prediction Scheme Using Multipath Separation in the Delay and Angle Domains
奥村 香菜子, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 132, 61, 66, 19 Jul. 2017
電子情報通信学会, Japanese

Performance Evaluation on Beam Selection Rules and Beam Shapes of a Massive MIMO System in Time-varying Environments
山本 順平, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 武田 大樹, 岸山 祥久, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 103, 31, 36, 21 Jun. 2017
電子情報通信学会, Japanese

Fundamental Considerations on Computational Complexity Reduction Using Receive Matrix Interpolation in a MIMO-OFDM System
齋藤 剣聖, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 103, 121, 126, 21 Jun. 2017
電子情報通信学会, Japanese

A Study on Placements of Distributed Antenna Arrays in an Indoor Multi-User Massive MIMO System
鈴木 裕也, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 103, 127, 132, 21 Jun. 2017
電子情報通信学会, Japanese

Loose Beamforming by Antenna Selection in a Multi-User Massive MIMO System
井上 航一, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 117, 11, 155, 159, 24 Apr. 2017
電子情報通信学会, Japanese

大規模MIMOシステムのビーム形状に関する特性評価
山本順平, 西村寿彦, 大鐘武雄, 小川恭孝, 武田大樹, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2017, 2017

A Study on Beam Selection Rules and Beam Shapes for Hybrid Beamforming
山本 順平, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 武田 大樹, 岸山 祥久, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 383, 147, 152, 21 Dec. 2016
電子情報通信学会, Japanese

Performance Evaluation of a Full-Dimension MIMO Base Station Using a Ray-tracing Technique
西崎 隼, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 318, 79, 84, 24 Nov. 2016
電子情報通信学会, Japanese

Invited Talk : SINR Evaluation of a Rectangular FD-MIMO System in Various Indoor Environments
西村 寿彦, 西崎 隼, 小川 恭孝, 大鐘 武雄, 映像情報メディア学会技術報告 = ITE technical report, 40, 23, 51, 54, Jul. 2016
映像情報メディア学会, Japanese

A Study on Normalization of A-priori Information for Belief Propagation in Correlated Large MIMO Channels
Takumi Takahashi, Shinsuke Ibi, Takeo Ohgane, Seiichi Sampei, IEICE Tech. Rep, 116, 110, 53, 58, 23 Jun. 2016
Japanese

A Study on Interference Cancellation Using Belief Propagation in Faster-than-Nyquist Signaling
木原 光太郎, 西村 寿彦, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 110, 47, 52, 22 Jun. 2016
電子情報通信学会, Japanese

Considerations on a Channel Prediction Scheme Based on Impulse Response Estimation
奥村 香菜子, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 110, 81, 86, 22 Jun. 2016
電子情報通信学会, Japanese

Performance Evaluation of Suppression of Scattereing Waves Using a Gating Technique from Outside of a Search Area in Scatterer Detection Based on Compressed Sensing
阿部 大輔, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 506, 69, 74, 10 Mar. 2016
電子情報通信学会, Japanese

Channel Prediction Using 2-Step Compressed Sensing in a Time-Varying Multi-User MIMO Environment
上橋 俊介, 小川 恭孝, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 472, 357, 362, 02 Mar. 2016
電子情報通信学会, Japanese

B-1-194 DOA Estimation using Compressed Sensing Technique for Multi-band Signals with Frequency Characteristics
Endo Taiki, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 2016, 1, 194, 194, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-43 A Study on Analogue Beamformer with a Butler Matrix under Nakagami-Rice Fading Environments
Yuki Shuto, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2016, 1, 436, 436, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-102 Trajectory Evaluation in Belief Propagation for Channel Equalization
Hagiwara Mitsuyoshi, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2016, 1, 495, 495, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-103 Considerations on LLR Damping in a Massive MIMO System with Belief Propagation
Tanno Shuhei, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2016, 1, 496, 496, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-119 Improvement of Channel Prediction Using Compressed Sensing in a Multi-User MIMO Environment with Moving Scatterers
Uehashi Shunsuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2016, 1, 512, 512, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-153 Considerations on Alternative Routing in a Wireless Mesh Network with an Adaptive Array
Suzuki Kosuke, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2016, 1, 546, 546, 01 Mar. 2016
The Institute of Electronics, Information and Communication Engineers, Japanese

An EXIT Analysis for Belief-Propagation Based Channel Equalization
萩原 光義, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 288, 7, 12, 04 Nov. 2015
電子情報通信学会, Japanese

A Study on LLR Updating in an LDPC Coded Massive MIMO System with Belief Propagation
丹野 柊平, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 288, 37, 42, 04 Nov. 2015
電子情報通信学会, Japanese

16-QAM Signal Detection Using Belief Propagation in a Massive MIMO System
宇佐美 友也, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 288, 43, 48, 04 Nov. 2015
電子情報通信学会, Japanese

Performance Evaluation of Full-Dimension MIMO Systems with Consideration for User Density Using a Ray-tracing Technique
西崎 隼, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 288, 127, 132, 04 Nov. 2015
電子情報通信学会, Japanese

B-5-82 A Study on LDPC Decoding in Massive MIMO Detection with Belief Propagation
Tanno Shuhei, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2015, 1, 344, 344, 25 Aug. 2015
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-83 Weighted LLR Damping in Belief Propagation for Channel Equalization
Hagiwara Mitsuyoshi, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2015, 1, 345, 345, 25 Aug. 2015
The Institute of Electronics, Information and Communication Engineers, Japanese

BS-2-5 Indoor SINR Performance of a Rectangular Array type FD-MIMO
Nishimura Toshihiko, Nishizaki Shun, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2015, 1, "S, 39"-"S-40", 25 Aug. 2015
The Institute of Electronics, Information and Communication Engineers, Japanese

B-1-142 Considerations on Detection of the Number of Scatterers Using Compressed Sensing with Thresholding
Abe Daisuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2015, 1, 142, 142, 25 Aug. 2015
一般社団法人電子情報通信学会, Japanese

B-5-10 Doppler Frequency Estimation and Channel Prediction Using Compressed Sensing
Uehashi Shunsuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2015, 1, 272, 272, 25 Aug. 2015
一般社団法人電子情報通信学会, Japanese

B-5-26 A Study on a High Frequency Band Beamformer with a Butler Matrix
Yuki Shuto, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2015, 1, 288, 288, 25 Aug. 2015
一般社団法人電子情報通信学会, Japanese

B-5-81 Performance Evaluation of Full-Dimension MIMO Systems with Increasing a Number of BS Antenna Elements
Nishizaki Shun, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2015, 1, 343, 343, 25 Aug. 2015
一般社団法人電子情報通信学会, Japanese

Evaluation of DOA Estimation Using a Compressed Sensing Technique for Arrival Signals with Different Amplitudes
遠藤 大樹, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 164, 107, 112, 30 Jul. 2015
電子情報通信学会, Japanese

Performance Evaluation of Full-Dimension MIMO Systems with a Different Number of BS Antenna Elements Using a Ray-tracing Technique
西崎 隼, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 113, 241, 246, 24 Jun. 2015
電子情報通信学会, Japanese

A Study on Channel Decoding in Massive MIMO Detection with Belief Propagation
丹野 柊平, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 113, 257, 261, 24 Jun. 2015
電子情報通信学会, Japanese

A Study on LLR Damping in Belief Propagation for Channel Equalization
萩原 光義, 西村 寿彦, 大鐘 武雄, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 113, 263, 267, 24 Jun. 2015
電子情報通信学会, Japanese

B-5-19 Channel Prediction Using Compressed Sensing in TDD Multi-User MIMO Systems
Uehashi Shunsuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2015, 1, 374, 374, 24 Feb. 2015
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-53 Performance Evaluation for Alternative Routing in a Wireless Mesh Network with an Adaptive Array
Suzuki Kosuke, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2015, 1, 408, 408, 24 Feb. 2015
The Institute of Electronics, Information and Communication Engineers, Japanese

B-1-193 Detection of Scatterers Using Compressed Sensing with a Time-Domain Gating Technique
Kusano Kaoru, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2015, 1, 193, 193, 24 Feb. 2015
一般社団法人電子情報通信学会, Japanese

B-5-111 A Study on BP-based Approach in a 16 QAM Modulated Massive MIMO System
Usami Tomoya, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2015, 1, 466, 466, 24 Feb. 2015
一般社団法人電子情報通信学会, Japanese

B-5-167 Channel Equalization Using a Belief Propagation Algorithm with High Rate Codes
Sugita Masatomo, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2015, 1, 522, 522, 24 Feb. 2015
一般社団法人電子情報通信学会, Japanese

BS-1-1 Parameter Dependency on an Arrival Wave Number in DOA Estimation Using a Compressed Sencing Technique
Endo Taiki, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 2015, 1, "S, 1"-"S-2", 24 Feb. 2015
一般社団法人電子情報通信学会, Japanese

BP-1-4 MIMO and Beamforming Technologies for 5G
Ohgane Takeo, Ogawa Yasutaka, Nishimura Toshihiko, Proceedings of the IEICE General Conference, 2015, 1, "SS, 9"-"SS-10", 24 Feb. 2015
一般社団法人電子情報通信学会, Japanese

Considerations on a Channel Prediction Scheme Using Compressed Sensing in Multi-User MIMO Systems
UEHASHI Shunsuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 114, 395, 55, 60, 22 Jan. 2015
In multi-user MIMO systems, a base station needs downlink channel state information (CSI) to each user to suppress inter-user interference and inter-stream interference. In wireless communication, however, signal propagation environments are time-varying, and CSI obtained at the base station is different from the channel at the actual transmission time because we have delay. This deteriorates communication quality. To solve this problem, some channel prediction schemes have been developed. So far, we have proposed a channel prediction scheme using a compressed sensing technique. This scheme can predict channel with high accuracy even when the number of arrival waves is large. In this paper, we evaluate the effect of the proposed method in multi-user MIMO systems., 一般社団法人電子情報通信学会, Japanese

A throughput evaluation of an over-distributed antenna system with signal distributing or switching under control delay
NAKANISHI Yuki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, OHWATARI Yusuke, KISHIYAMA Yoshihisa, Technical report of IEICE. RCS, 114, 395, 61, 66, 22 Jan. 2015
When a base station has many transmit antennas such as a massive MIMO system, we need as many pilot resources as the transmit antennas to estimate channel state information (CSI) and its feedback in an FDD system, and thus transmission efficiency degrades. In our previous study, we have proposed an over-distributed antenna system (O-DAS) with much more transmit antennas than limited pilot resources, and have shown an improvement of the peak throughput under a perfect CSI assumption. However, the CSI is outdated if control delay exists, and thus it may cause the inter-user-interference which seriously degrades the transmission performance. In this paper, we evaluate the throughput performance of the O-DAS for two transmission methods, namely, signal distributing and switching, in time-varying environments with a control delay. Compared with the case in non time-varying environments, it is shown that the performance degradation of signal switching is not serious and that the signal distributing still provides sufficient gain although the profitable range becomes narrow., 一般社団法人電子情報通信学会, Japanese

A BP-based approach for M-QAM signal detection in a fully massive MIMO system
USAMI Tomoya, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 114, 395, 163, 168, 22 Jan. 2015
With the rapid traffic growth, a massive multiple-input multiple-output (MIMO) system with an order of 100 elements has been discussed recently. Increasing the number of both transmit and receive antennas improves peak data rate and capacity, but requires the complexity proportional to at least the third power of the number of antenna elements to detect spatially-multiplexed signals in general. Thus, the implementation of a fully massive MIMO system becomes very difficult. To solve this problem, detection based on the belief propagation has been developed and studied. It has been shown that the belief propagation is implementable in the order of the second power of the number of elements and achieves very good BER performance in a QPSK modulated massive MIMO system. But it is essential to study a multi-level QAM modulated massive MIMO system in the viewpoint of peak throughput. In this paper, we apply the belief propagation to a 16-QAM modulated massive MIMO system and have shown that starting the process from error-tolerant bit nodes improves the BER performance., 一般社団法人電子情報通信学会, Japanese

An impact of alternative routing in a wireless mesh network with an adaptive array
SUZUKI Kosuke, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 114, 372, 135, 140, 18 Dec. 2014
In a wireless mesh network, the interference between nearby links is not negligible and thus degrades the area spectral efficiency. There have been many works on a use of directional antennas capable of forming a narrow beam to a destination node. An adaptive array capable of controlling not only beams but also nulls is more effective for reducing interference, and thereby the possibility to establish new links increases. Here, an alternative route enables avoiding resource competitions and improves the possibility of new link establishment. In the paper, we evaluate the system throughput performance in a wireless mesh network consisting of nodes having alternative routes and an adaptive array function., 一般社団法人電子情報通信学会, Japanese

A Study of Channel Equalization Using a Belief Propagation Algorithm
SUGITA Masatomo, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 114, 295, 37, 42, 12 Nov. 2014
Frequency-domain equalization is well known as a countermeasure for inter-symbol interference in a single carrier transmission system in terms of light weight and reasonably high performance. Frequency-domain turbo equalization with iterative processing has been developed as the extension to provide very high performance. In this paper, we consider a channel equalizer using a belief propagation (BP) algorithm in the time domain. In multiple-input multiple-output multi-path environments, it has been reported that this algorithm achieves a near-optimum BER performance. However, in single-input single-output (SISO) multi-path environments, the normal BP algorithm does not work. We show the problems and a solution against that. And we evaluate the BER performance with our proposal in a SISO multi-path environment., 一般社団法人電子情報通信学会, Japanese

Considerations on Channel Prediction Schemes Using Compressed Sensing
UEHASHI Shunsuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 114, 245, 1, 6, 15 Oct. 2014
In wireless communication, channel estimation using pilot symbols is essential. If we need to transmit many pilot symbols in time-varying environments, the transmission efficiency is lowed. Also, channel state information (CSI) obtained by the pilot symbols is different from the channel at the actual transmission time because we have delay. This deteriorates communication quality. To solve this problem, some channel prediction schemes have been developed. In this paper, we propose a channel prediction scheme which combines a sum-of-sinusoids (SOS) method and direction-of-arrival (DOA) estimation using a compressed sensing technique. Using simulation, it is shown that the proposed method realizes highly precise channel prediction., The Institute of Electronics, Information and Communication Engineers, Japanese

Study on Parameter Dependence of DOA Estimation of Multi-band Signals using a Compressed Sensing Technique
ENDO Taiki, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 114, 245, 7, 12, 15 Oct. 2014
In recent years, much attention has been paid to DOA estimation using a compressed sensing technique. We have studied a DOA estimation method of multi-band signals with frequency characteristics. Using multi-band signals, we can achieve higher probability of correct estimation that using single-band signals and estimate more waves than the number of antenna elements. The half-quadratic regularization (HQR) method is a technique to solve a linear programming problem of the compressed sensing technique. In this paper, we study dependence property of three parameters in the HQR method for probability of correct estimation and obtaine adequate values of the parameters., 一般社団法人電子情報通信学会, Japanese

B-1-172 Dependency of Parameters for DOA Estimation of Multiband Signals using a Compressed Sensing Technique
Endo Taiki, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2014, 1, 172, 172, 09 Sep. 2014
一般社団法人電子情報通信学会, Japanese

B-5-50 Considerations on Channel Prediction Using Compressed Sensing
Uehashi Shunsuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2014, 1, 321, 321, 09 Sep. 2014
一般社団法人電子情報通信学会, Japanese

B-5-51 SINK Performance Comparison for Different Areas of User Distribution in Indoor Full-Dimension MIMO Systems Using a Ray-tracing Technique
Fukuda Hayato, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2014, 1, 322, 322, 09 Sep. 2014
一般社団法人電子情報通信学会, Japanese

DOA Estimation Applying Compressed Sensing Techniques
NISHIMURA T, ENDO T, OGAWA Y, OHGANE T, Technical report of IEICE. SANE, 114, 194, 65, 70, 28 Aug. 2014
It has been proposed to apply compressed sensing methods to problems estimating the direction of arrival angles of radio waves. Using the proposed method, angular resolution can be more precise than the traditional methods such as the MUSIC. If the arrival waves are multiband signal spread over a wide-frequency-band, the performance can be improved. Furthermore, the performance enhancement can be expected by using the Khatri-Rao product and normalization of power even when the arrival waves have frequency dependency. We show how the compressed sensing method is applied, and then we explain how the method using the Khatri-Rao product and normalization of power is applied. The effectiveness of our proposal is confirmed by some simulation results., 一般社団法人電子情報通信学会, Japanese

DOA Estimation Applying Compressed Sensing Techniques
NISHIMURA T, ENDO T, OGAWA Y, OHGANE T, IEICE technical report. Antennas and propagation, 114, 193, 79, 84, 28 Aug. 2014
It has been proposed to apply compressed sensing methods to problems estimating the direction of arrival angles of radio waves. Using the proposed method, angular resolution can be more precise than the traditional methods such as the MUSIC. If the arrival waves are multiband signal spread over a wide-frequency-band, the performance can be improved. Furthermore, the performance enhancement can be expected by using the Khatri-Rao product and normalization of power even when the arrival waves have frequency dependency. We show how the compressed sensing method is applied, and then we explain how the method using the Khatri-Rao product and normalization of power is applied. The effectiveness of our proposal is confirmed by some simulation results., 一般社団法人電子情報通信学会, Japanese

SINR Performance Comparison of Full-Dimension MIMO Systems in Indoor Environments Using a Ray-tracing Technique
FUKUDA Hayato, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 114, 180, 1, 6, 19 Aug. 2014
In order to realize high capacity communication, massive multiple-input multiple-output (MIMO) systems which have a very large number of antenna elements at a base station (BS) or an access point (AP) have been studied for future cellular systems. It is, however, difficult to build the massive MIMO system because the installation space is limited. To cope with this limitation, a full-dimension MIMO (FD-MIMO) system where antenna elements are placed on a 2D grid at the BS or AP for MIMO transmission is proposed. The 2D antenna array saves the space and allows elevation beamforming as well as azimuth beamforming. In this paper, we evaluate performance of the FD-MIMO in indoor Line-of-Sight environments compared with that of a ID antenna arrangement using a ray tracing technique which enables to obtain channel matrices between BS and user terminals. It has been shown that FD-MIMO with a small rectangular antenna array performs better than ID antenna array when users are located near the BS., 一般社団法人電子情報通信学会, Japanese

An evaluation of multiuser MIMO throughput in a distributed antenna system with signal distribution
NAKANISHI Yuki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, OHWATARI Yusuke, KISHIYAMA Yoshihisa, Technical report of IEICE. RCS, 114, 180, 7, 12, 19 Aug. 2014
A distributed antenna system, where antennas of a base station are spatially distributed over the cell, can improve throughput at the cell edge compared to a centralized antenna system but reduces peak throughput. Therefore, it is expected that we can obtain higher throughput by increasing the number of antennas per remote antenna unit. In general, we need to send as many pilot sequences as transmit antennas to estimate channel state information and thus transmission efficiency degrades. In this paper, we present a novel system where we distribute the same signal to several antennas to increase the number of antennas without increasing the number of pilot sequences. We show the throughput improvement with signal distribution and evaluate the effect of weighted signal distribution., 一般社団法人電子情報通信学会, Japanese

大規模MIMOの基本概念と送受多素子化への展開
大鐘武雄, 宇佐美友也, 福田航, 小川恭孝, 西村寿彦, 電子情報通信学会大会講演論文集(CD-ROM), 2014, ROMBUNNO.ABS-1-1, 54"-"S-55", 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

シングルキャリアE‐SDM方式におけるPAPR削減
田中友基, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-21, 416, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

チャネル推定誤差環境下におけるチャネル予測を用いたマルチユーザMIMOシステムに関する考察
山口歌奈子, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-1-216, 216, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

マルチセル環境における分散アンテナシステムのアンテナ選択に伴うパイロット信号削減効果
中西裕基, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-80, 475, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

有相関伝搬路における確率伝搬法を用いた大規模MIMO信号検出
福田航, 安孫子卓史, 西村寿彦, 大鐘武雄, 小川恭孝, 大渡裕介, 川村輝雄, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-33, 428, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

Khatri‐Rao変換を用いた広帯域DOA推定法の誤差軽減
白井智士, 山田寛喜, 西村寿彦, 小川恭孝, 大鐘武雄, 山口芳雄, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-1-228, 228, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

周波数特性を有するマルチバンド信号の圧縮センシング到来方向推定
寺田翼, 西村寿彦, 小川恭孝, 大鐘武雄, 山田寛喜, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-1-231, 231, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

有相関MIMO伝搬路におけるBP法のEXIT解析に関する基礎的検討
安孫子卓史, 福田航, 西村寿彦, 大鐘武雄, 小川恭孝, 大渡裕介, 川村輝雄, 岸山祥久, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-35, 430, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

LabVIEWとUSRPを用いた無線メッシュネットワーク用指向性制御の基礎的検討
出雲恭輔, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-158, 553, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

確率伝搬アルゴリズムを適用した適応等化
杉田大智, 福田航, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-100, 495, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

リソース配分を適用した広帯域伝送系におけるシングルキャリアマルチユーザE‐SDM方式に関する検討
原田佳太, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集(CD-ROM), 2014, 1, ROMBUNNO.B-5-78, 473, 04 Mar. 2014
The Institute of Electronics, Information and Communication Engineers, Japanese

High Reliability Vehicle-to-vehicle Communication System
SAI SEII, DOI YOSHIHARU, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, 電子情報通信学会技術研究報告, 113, 456(RCS2013 306-396), 169, 174, 24 Feb. 2014
Japanese

DOA Estimation of Multi-band Signals with Frequency Characteristics
TERADA TSUBASA, NISHIMURA TOSHIHIKO, OGAWA YASUTAKA, OGANE TAKEO, YAMADA HIROYOSHI, 電子情報通信学会技術研究報告, 113, 300(AP2013 100-123), 93, 98, 13 Nov. 2013
Japanese

Considerations on Prediction Effects of Multi-User MIMO Channels in Time-Varying Environments
YAMAGUCHI KANAKO, OGAWA YASUTAKA, NISHIMURA TOSHIHIKO, OGANE TAKEO, 電子情報通信学会技術研究報告, 113, 300(AP2013 100-123), 43, 48, 13 Nov. 2013
Japanese

A Study on BP-based Signal Detection for a Massive MIMO system in Spatially Correlated Channels
FUKUDA WATARU, ABIKO TAKASHI, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, OWATARI YUSUKE, KAWAMURA TERUO, KISHIYAMA YOSHIHISA, 電子情報通信学会技術研究報告, 113, 301(RCS2013 174-205), 55, 60, 13 Nov. 2013
Japanese

Considerations on Detection of Scatterers Using Compressed Sensing
Kusano Kaoru, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2013, 1, 209, 209, 03 Sep. 2013
一般社団法人電子情報通信学会, Japanese

Performance Evaluation for a pilot"-"Signal"-"Shared capacity in a multiuser MIMO distributed antenna system
Nakanishi Yuki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2013, 1, 396, 396, 03 Sep. 2013
一般社団法人電子情報通信学会, Japanese

Considerations on Detection of Scatterers Based on Compressed Sensing
KUSANO KAORU, OGAWA YASUTAKA, NISHIMURA TOSHIHIKO, OGANE TAKEO, 電子情報通信学会技術研究報告, 113, 151(AP2013 46-61), 43, 48, 16 Jul. 2013
Japanese

Linear Algebra Tips for Understanding MIMO
OHGANE Takeo, Technical report of IEICE. RCS, 113, 93, 211, 211, 13 Jun. 2013
一般社団法人電子情報通信学会, Japanese

Experimental Evaluation of MIMO Single-carrier Block Transmission with 1024QAM Using FPGA-based Testbed
YAMAGUCHI KANAKO, NISHIMOTO HIROSHI, OKAZAKI AKIHIRO, SANO HIROYASU, ISHIZU FUMIO, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, 電子情報通信学会技術研究報告, 113, 93(RCS2013 37-77), 193, 198, 13 Jun. 2013
Japanese

An impact of reduced pilot signals on capacity of a multiuser MIMO system with distributed antennas
NAKANISHI YUKI, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, 電子情報通信学会技術研究報告, 113, 93(RCS2013 37-77), 55, 60, 13 Jun. 2013
Japanese

Considerations on a Multi-User Single-Carrier E-SDM Scheme in Wideband Transmissions
HARADA KEITA, OGAWA YASUTAKA, NISHIMURA TOSHIHIKO, OGANE TAKEO, 電子情報通信学会技術研究報告, 113, 93(RCS2013 37-77), 49, 54, 13 Jun. 2013
Japanese

圧縮センシング法を用いたマルチバンド信号到来方向推定の検討
寺田翼, 西村寿彦, 小川恭孝, 大鐘武雄, 電子情報通信学会大会講演論文集, 2013, 1, 198, 198, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

ARモデルに基づくチャネル予測を用いた時変動マルチユーザMIMOシステムの考察
山口歌奈子, BUI Huu Phu, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集, 2013, 1, 217, 217, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

OFDMを用いた上り回線仮想MIMOシステムにおける端末移動速度の影響に関する検討
小林拓也, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集, 2013, 1, 440, 440, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

広帯域伝送系におけるマルチユーザE‐SDM方式に関する検討
原田佳太, 小川恭孝, 西村寿彦, 大鐘武雄, 電子情報通信学会大会講演論文集, 2013, 1, 414, 414, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

Full‐Duplex AFリレーにおけるMMSE‐FDEに関する検討
清見直史, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集, 2013, 1, 580, 580, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

BPアルゴリズムを用いた大規模MIMO信号検出の繰り返し処理に関するEXIT解析
安孫子卓史, 福田航, 西村寿彦, 大鐘武雄, 小川恭孝, 大渡裕介, 岸山祥久, 電子情報通信学会大会講演論文集, 2013, 1, 422, 422, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

格子基底縮小を用いた符号化MIMO‐OFDMのLLR生成に関する検討
森谷健太郎, 西村寿彦, 大鐘武雄, 小川恭孝, 電子情報通信学会大会講演論文集, 2013, 1, 420, 420, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

確率伝搬アルゴリズムを用いた大規模MIMO信号検出
福田航, 安孫子卓史, 西村寿彦, 大鐘武雄, 小川恭孝, 大渡裕介, 岸山祥久, 電子情報通信学会大会講演論文集, 2013, 1, 421, 421, 05 Mar. 2013
The Institute of Electronics, Information and Communication Engineers, Japanese

Complexity Reduction Approaches for Signal Detection Based on Belief Propagation in a Large Scale MIMO System
FUKUDA WATARU, ABIKO TAKASHI, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, OWATARI YUSUKE, KISHIYAMA YOSHIHISA, 電子情報通信学会技術研究報告, 112, 424(RCS2012 238-283), 225, 230, 24 Jan. 2013
Japanese

Performance Evaluation of Belief-Propagation Algorithm with MRC for Signal Detection in a Large Scale MIMO System
ABIKO TAKASHI, FUKUDA WATARU, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, OWATARI YUSUKE, KISHIYAMA YOSHIHISA, 電子情報通信学会技術研究報告, 112, 424(RCS2012 238-283), 231, 236, 24 Jan. 2013
Japanese

Complexity reduction and performance evaluation of coded MIMO-OFDM using lattice reduction
MORITANI KENTARO, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, 電子情報通信学会技術研究報告, 112, 351(RCS2012 184-237), 257, 262, 06 Dec. 2012
Japanese

A Study on Full-Duplex AF Relay using FDE at Destination Node with Multiple Antenna Elements
KIYOMI NAOHITO, NISHIMURA TOSHIHIKO, OGANE TAKEO, OGAWA YASUTAKA, 電子情報通信学会技術研究報告, 112, 351(RCS2012 184-237), 203, 208, 06 Dec. 2012
Japanese

Performance Evaluations of an Uplink Virtual MIMO-OFDM System in Dynamic Channels
KOBAYASHI TAKUYA, OGAWA YASUTAKA, NISHIMURA TOSHIHIKO, OGANE TAKEO, 電子情報通信学会技術研究報告, 112, 351(RCS2012 184-237), 197, 202, 06 Dec. 2012
Japanese

USRPを用いたマルチホップネットワークの実装
出雲恭輔, 西村寿彦, 大鐘武雄, 小川恭孝, 電気・情報関係学会北海道支部連合大会講演論文集(CD−ROM), 2012, ROMBUNNO.118, 20 Oct. 2012
Japanese

シングルキャリアE‐SDM方式におけるPAPRの評価
田中友基, 小川恭孝, 西村寿彦, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD−ROM), 2012, ROMBUNNO.119, 20 Oct. 2012
Japanese

Time‐Reversal法を用いた多元接続方式に関する検討
原田佳太, 小川恭孝, 西村寿彦, 大鐘武雄, 電気・情報関係学会北海道支部連合大会講演論文集(CD−ROM), 2012, ROMBUNNO.117, 20 Oct. 2012
Japanese

A study on Signal Detection in a Large Scale MIMO System : Concept and BER Performance
FUKUDA Wataru, ABIKO Takashi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, OHWATAR Yusuke, KISHIYAMA Yoshihisa, Technical report of IEICE. RCS, 112, 239, 7, 12, 10 Oct. 2012
The easiest way to improve the throughput performance of multiple-input multiple-output (MIMO) systems is increasing the number of both transmit and receive antennas. In general, however, algorithms detecting spatially-multiplexed signals require the complexity proportional to the third power of the number of antenna elements in the least case. Thus, the implementation of an antenna array with an order of 100 elements becomes very difficult. In this paper, we evaluate the algorithm based on belief propagation with parallel interference cancellers. This algorithm is implementable in the order of the second power of the number of elements, and it has been shown that the array with the order of 100 elements reveals very good BER performance., 一般社団法人電子情報通信学会, Japanese

A Study on Signal Detection in a Large Scale MIMO System : An EXIT Chart Analysis of Iterative Processing
ABIKO Takashi, FUKUDA Wataru, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, OHWATAR Yusuke, KISHIYAMA Yoshihisa, Technical report of IEICE. RCS, 112, 239, 13, 18, 10 Oct. 2012
Multiple-input multiple-output (MIMO) systems are well known as a method to improve the throughput performance. Recently, a concept of massive (or very large) MIMO using an antenna array with an order of 100 elements has been proposed. In general, the complexity order of signal detection in such a MIMO system becomes the third power of the number of antenna elements in the least case. The authors have evaluated the belief propagation based algorithm with parallel interference cancellers and shown that it is implementable in the order of the second power of the number of elements. Here, the extrinsic information transfer analysis is applied to evaluate the convergence performance., 一般社団法人電子情報通信学会, Japanese

送信側空間平滑法を用いた広帯域信号到来方向推定の精度評価
寺田翼, 西村寿彦, 小川恭孝, 大鐘武雄, 電子情報通信学会大会講演論文集, 2012, 1, 203, 203, 28 Aug. 2012
The Institute of Electronics, Information and Communication Engineers, Japanese

Sequential Gating Processing for Time-Reversal MUSIC
CHOI Heedong, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 112, 149, 17, 22, 18 Jul. 2012
Time-reversal (TR) approach with multiple signal classification (MUSIC) has been developed for a remote sensing system due to super-resolution and statistical stability. Especially, TR-MUSIC imaging using the angle- and/or time-domain gating (filtering) technique in early papers provides a tremendous enhancement for the imaging results by reducing noise components and relaxing the antenna restriction. In this paper, we address the formulation of our approach, and discuss its performance in more detail., 一般社団法人電子情報通信学会, English

IEICE Transactions on Communications : Editor's Message
OHGANE Takeo, IEICE transactions on communications, 95, 6, 1982, 1982, 01 Jun. 2012
English

Correlation Suppression Performance of Spatial Smoothing Preprocessing at a Transmitter for DOA Estimation of Wide-band Signals
MAEDA Kyouhei, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 111, 487, 25, 30, 08 Mar. 2012
Recently, due to the wide spread of wireless communications, importance of a precise direction-of-arrival (DOA) estimation technology has become greater in order to investigate propagation environments or determine terminal's positions. The authors have proposed the precise DOA estimation method of wide-band signals. First, coarse DOAs are estimated at the lowest frequency band where grating lobes do not appear. Next, precise DOA estimation is done at a higher frequency band in a narrower search range to prevent grating lobes. In this paper, to estimate DOA accurately under multipath environments, we use multiple antenna elements at a transmitter and apply spatial smoothing preprocessing (Transmit-SSP). The multiple signals transmitted from different positions cause correlation reduction effect. From computer simulations, we show the correlation suppression effect and high accuracy of the proposed method., 一般社団法人電子情報通信学会, Japanese

B-1-224 Considerations on a Frequency Correlation for a Distributed Antenna System
YAMAGUCHI Kanako, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2012, 1, 224, 224, 06 Mar. 2012
The Institute of Electronics, Information and Communication Engineers, Japanese

B-1-186 A Study on DOA Estimation of Wide-band Signals Using Spatial Smoothing Preprocessings at Transmitter
Maeda Kyouhei, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 2012, 1, 186, 186, 06 Mar. 2012
一般社団法人電子情報通信学会, Japanese

B-5-54 Performance Evaluations of an OFDM Uplink Virtual MIMO System Compensating for Frequency Offsets
KOBAYASHI Takuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2012, 1, 453, 453, 06 Mar. 2012
一般社団法人電子情報通信学会, Japanese

B-5-80 A study on complexity reduction of a MIMO detection algorithm with lattice reduction
MORITANI Kentaro, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 2012, 1, 479, 479, 06 Mar. 2012
一般社団法人電子情報通信学会, Japanese

B-5-166 A Study on Multi-Hop Networks Using an Adaptive Array Under a Bursty Traffic Model
Takeda Daiki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2012, 1, 565, 565, 06 Mar. 2012
一般社団法人電子情報通信学会, Japanese

超高速ブロードバンドアクセスにおけるMIMOチャネル伝送技術
大鐘武雄, 小川恭孝, 西村寿彦, 電子情報通信学会大会講演論文集, 2012, SS.7-SS.8, 06 Mar. 2012
Japanese

Considerations on Reduced-Complexity Single-Carrier E-SDM for Wideband Transmissions
DAVIDESCU Cristian, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 111, 451, 55, 60, 29 Feb. 2012
Single-carrier modulation combined with frequency-domain equalization (FDE) at the receiver has been proposed as an alternative to the OFDM system for the uplink transmission, in the case of severe frequency-selective fading channels. Furthermore, an eigenbeam-space division multiplexing (E-SDM) technique can be used to improve the spectrum efficiency. In order to reduce computational complexity at the transmitter, some techniques decreasing the number of singular value decompositions have been proposed. In this paper, we propose some reduced-complexity techniques that can improve the bit error rate (BER) performance. The evaluations of these techniques and the trade-off between complexity and BER are analyzed by computer simulations., 一般社団法人電子情報通信学会, English

Frequency Offset Estimation and its Compensation in an Uplink Virtual MIMO System Using OFDM
KOBAYASHI Takuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 111, 451, 61, 66, 29 Feb. 2012
We need a wider frequency bandwidth for high-speed transmission, and thus a higher frequency band will be used in future mobile communications. However, the propagation loss increases in a higher frequency band. It causes degradation of communication quality especially for an uplink channel because the power is supplied by the terminal battery. Then, it has been proposed that a communication terminal cooperates with nearby terminals to solve this problem. However, different frequency offsets of the terminals cause different phase rotations. In this paper, we propose a frequency offset estimation and compensation scheme of them. We evaluate the performance of the virtual MIMO-based OFDM communications using the compensation scheme., 一般社団法人電子情報通信学会, Japanese

Considerations on a Frequency Correlation for a Multiple-Antenna System
YAMAGUCHI Kanako, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 111, 451, 67, 72, 29 Feb. 2012
In wireless communication channels, we have multipath propagation due to a large number of reflected and diffracted waves. When the delay difference between multipath waves is not negligible, we encounter frequency selective fading. Thus far, a frequency correlation defined for a single receive antenna has been used for evaluating the frequency selectivity. Recently, multiple antennas have been introduced to realize space diversity and/or spatial filtering. Then, the conventional frequency correlation defined for a single antenna cannot be used for a multiple-antenna system. In this paper, we extend the frequency correlation to a multiple-antenna system. Moreover, we compare the newly-introduced correlation with the conventional one and the error for signal detection under several propagation environments., 一般社団法人電子情報通信学会, Japanese

Investigation of Dual Threshold Scaling Factors for Bit Flip Decoding
WEBBER Julian, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 111, 345, 1, 6, 08 Dec. 2011
Very low error rates can be obtained using low-density parity-check (LDPC) codes and their use is now common in new communications standards such as the Long Term Evolution (LTE) Advanced. The decoders based on belief propagation offer excellent performance but have high complexity. Therefore simpler architectures based on the bit flipping algorithm have been researched. Over the last two years a few adaptive threshold algorithms have been proposed in which a bit is either inverted if it is below a threshold, or the threshold itself is lowered using a scaling factor. This work looks at how the scaling factor influences the iteration count and error performance. We propose an algorithm that switches between two scaling factors based on the syndrome sum on each branch. Using this technique we show that the error performance is comparable with that of a single scaling factor but the iteration count is significantly reduced. Further, if a non-transmitted codeword is detected, which corresponds to a trapped search point, an addition of a small noise perturbation can potentially provide an escape opportunity and this is experimentally investigated., 一般社団法人電子情報通信学会, Japanese

Optimazation of High Accuracy DOA Estimation Using Wide-band Signals
MAEDA Kyouhei, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 111, 288, 1, 6, 16 Nov. 2011
Recently, with the spreading of wireless communication technology, importance of a precise direction of arrival (DOA) estimation technology becomes larger in order to investigate propagation environments or determine terminal's positions. An array antenna is used in general DOA estimation algorithms. In a case where antenna element positions of the array are fixed, the higher frequency signal is used, the higher resolution DOA estimation is obtained. However, calculation load increases because we must calculate MUSIC spectra with a narrow angle step. Also, grating lobes occur when using high frequency signals for a fixed element interval. The authors have proposed the DOA estimation method based on the MUSIC algorithm using wide-band signals to solve these problems. First, coarse DOA is estimated at the lowest frequency band where grating lobes do not appear. Next, precise DOA estimation is done at a higher frequency band in a narrower search range to prevent grating lobes and increase of calculation load. In this paper, to estimate DOA using higher frequency signals while avoiding grating lobes, we optimize the frequency, search range, step width., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of an Uplink Virtual MIMO System Using OFDM
KOBAYASHI Takuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 111, 289, 185, 190, 09 Nov. 2011
In future mobile communication, we need wider frequency bandwidth transmission in a higher frequency band. However, the propagation loss increases in a high frequency band. It causes a degradation of communication quality. Especially for an uplink channel, the transmission power is limited because the power is supplied by the battery. Then, it has been proposed that a communication terminal cooperates with nearby terminals to solve this problem. The virtual MIMO-based cooperative communication using a single carrier in a narrow bandwidth has been examined in detail. In this paper, we evaluate the characteristics of the virtual MIMO-based cooperative communication using OFDM., 一般社団法人電子情報通信学会, Japanese

Transmit Beamforming at Source Node in MISO/MIMO AF Relay
KIYOMI Naohito, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 111, 289, 203, 208, 09 Nov. 2011
Data transmission through relay nodes has been studied as a method to improve transmission quality in wireless mesh networks and cellular systems. Multiple antenna elements at a source node enable adaptive beamforming and thus improve total performance of the relay transmission. In this paper, we propose simple transmit beamforming at a source node when the source node has two or more antenna elements and knows all channel information in MISO/MIMO amplify-and-forward relay with direct link and evaluate the packet error rate., 一般社団法人電子情報通信学会, Japanese

B-5-22 Low-Complexity Threshold Updating for LDPC Bit-Flip Decoders
Webber Julian, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2011, 1, 30 Aug. 2011
一般社団法人電子情報通信学会, English

B-5-129 Transmit Beamforming at Source Node in AF Relay
KIYOMI Naohito, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 2011, 1, 508, 508, 30 Aug. 2011
一般社団法人電子情報通信学会, Japanese

B-5-130 A Study on Routing for Multi-Hop Wireless Networks Using Adaptive Arrays
Takeda Daiki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2011, 1, 509, 509, 30 Aug. 2011
一般社団法人電子情報通信学会, Japanese

BS-2-11 Considerations on TR-MUSIC Imaging using the Time-Domain Gating
CHOI Heedong, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2011, 1, "S, 27"-"S-28", 30 Aug. 2011
一般社団法人電子情報通信学会, English

A Fundamental Study on Routing for Multi-Hop Wireless Networks Using Adaptive Array
TAKEDA Daiki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 111, 68, 1, 6, 19 May 2011
The interference between nearby links in a wireless multihop network degrades the area spectral efficiency. Thus there have been many works on a use of narrow beam antenna or adaptive array capable of forming nulls. In specific, the adaptive array allows the multiple links within a limited area by suppressing the interference among those. However, efficient routing is required to exploit the benefit. In the paper, the system throughput performance is evaluated under a partially-ideal routing, and the potential ability of the adaptive array is indicated., 一般社団法人電子情報通信学会, Japanese

A Study on High Accuracy DOA Estimation Using Wide-band Signals
MAEDA Kyouhei, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report, 111, 29, 65, 70, 05 May 2011
Recently, according to rapid spreading of cellular phones and wireless LAN equipment, importance of a precise direction of arrival (DOA) estimation technology becomes larger in order to investigate propagation environments or determine terminal's position. Generally, an array antenna with an estimation is used for the DOA estimation algorithm. In a case where the element position of array antenna is fixed, the higher frequency signal is used, the higher resolution DOA estimation is. However, calculation load increases because we must treat MUSIC spectra which have a narrow angle step and grating lobes occur by using high frequency signals for a fixed element interval. The authers have proposed the precise DOA estimation method using wide-band signals. In the beginning, coarse DOA is estimated at the lowest frequency band that grating lobes do not appear. Next, precise DOA estimation is done at higher frequency band in a narrower angle range in order to prevent grating lobes and calculation load. In this paper, we propose a method that can prevent grating lobes much effectively by changing adaptively the band in higher frequencies. We evaluated the performance of the technique using computer simulations. From the computer simulations, we show the highly accuracy of the proposed method., 一般社団法人電子情報通信学会, Japanese

B-5-91 An Evaluation of Transmit Diversity Gain in Generalized Block Diagonalization for Multiuser MIMO Downlink
Sada Tomoki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2011, 1, 477, 477, 28 Feb. 2011
一般社団法人電子情報通信学会, Japanese

A Study on Precoding Prediction in LTE Downlink
SHIMODA Yusuke, KISHIYAMA Yoshihisa, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 110, 433, 319, 323, 23 Feb. 2011
In the downlink of Long Term Evolution (LTE), it is planned to apply multiuser MIMO (MU-MIMO) systems for system capacity improvement. MU-MIMO transmission requires pre-coding at the transmitter side to decrease interference between users. In LTE, a code-book describing pre-coding matrices is defined. Thus, the user equipment is allowed to feed back the pre-coding matrix indicator only. In this paper, we consider a time-variant fading channel and evaluate the performance of pre-coding prediction to reduce degradation due to processing delay., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of GBD under Channel Estimation Errors for MU-MIMO Downlink
SADA Tomoki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 110, 369, 7, 12, 13 Jan. 2011
In a downlink (broadcast channel) of multiuser MIMO systems, we need to suppress the inter-user interference (IUI). It is known that block diagonalization and MMSE precoding are typical schemes for IUI suppression. In addition, we have proposed generalized block diagonalization (GBD) to achieve both high transmit diversity gain and IUI space limiting with a partial nulling concept. In this paper, we evaluate the impact of channel estimation error on the these precoding methods by computer simulations for BER performance., 一般社団法人電子情報通信学会, Japanese

A Study on Transmit Beamforming in an Interactive MIMO Wireless Relay
MATSUYA Sakiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 110, 369, 173, 178, 13 Jan. 2011
Recently, wireless relay systems have been discussed to achieve a flexible network for connecting ubiquitous communication terminals. Network coding that encodes the packets using XOR in the relay node reduces the number of transmission packets and thus improves throughput performance in the network. In our previous papers, we investigated beamforming techniques at the relay node for multicasting the network-coded data and proposed the capacity-maximizing criterion. In this paper, we expand the system model to a MIMO relay and propose a simple beamforming criterion. The high performance has been numerically confirmed., 一般社団法人電子情報通信学会, Japanese

B-1-195 Accuracy evaluation of DOA estimation with multi-band signals
Maeda Kyouhei, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 195, 195, 2011
The Institute of Electronics, Information and Communication Engineers, Japanese

Development of a channel emulator for evaluation of MIMO-OFDM and SC-FDMA systems
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka, APSIPA ASC 2011 - Asia-Pacific Signal and Information Processing Association Annual Summit and Conference 2011, 2011

Performance Evaluation of a Virtual MIMO System in an Uplink Channel
ITO Tatsuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 110, 340, 43, 48, 09 Dec. 2010
In future cellular radio, we need to transmit signals in a higher frequency band to accommodate a wider frequency bandwidth. The higher a frequency band is, the larger the propagation loss is. Also, a wider frequency bandwidth requires higher transmission power. For an uplink channel, however, the transmission power is limited because the power is supplied by the terminal battery. Thus, we will encounter a difficulty in sending uplink signals. The authors have proposed virtual MIMO-based cooperative communication to solve this problem. In this paper, we clarify bit error rate and packet error rate performances for various conditions. We evaluate the required transmission power. It has been shown that the virtual MIMO system requires lower transmission power than the conventional SIMO scheme., 一般社団法人電子情報通信学会, Japanese

Considerations on a Multi-User MIMO System Using Channel Prediction
BUI Huu Phu, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 110, 267, 47, 52, 03 Nov. 2010
A downlink multi-user MIMO system uses a block diagonalization scheme to suppress inter-user interference. Furthermore, the system can realize efficient transmission using eigenbeam-space division multiplexing. In time-varying environments, however, bit error rate (BER) performance seriously degrades because MIMO channels change during the time interval between transmission parameter determination and actual MIMO transmission. Channel prediction techniques have been proposed to improve the BER performance in dynamic environments. In this paper, based on indoor measurement data, we evaluate the BER performance of the downlink multiuser MIMO system with linear extrapolation and second order extrapolation., 一般社団法人電子情報通信学会, Japanese

B-5-13 An Impact of Channel Estimation Error on GBD for MU-MIMO Downlink
Sada Tomoki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2010, 1, 367, 367, 31 Aug. 2010
一般社団法人電子情報通信学会, Japanese

B-5-17 A Study on Precoding Prediction in MU-MIMO Downlink
Shimoda Yusuke, Nishimura Yoshihisa, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2010, 1, 371, 371, 31 Aug. 2010
一般社団法人電子情報通信学会, Japanese

BS-2-2 Evaluation of Transmission Power in an Uplink Virtual MIMO System in Dynamic Fading Environments
Ito Tatsuya, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2010, 1, "S, 9"-"S-10", 31 Aug. 2010
一般社団法人電子情報通信学会, Japanese

A Multi-User MIMO System in Time-Varying Environments
BUI Huu Phu, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 110, 135, 7, 12, 14 Jul. 2010
A multi-user MIMO system which simultaneously accommodates multiple users uses a block diagonalization scheme to suppress inter-user interference. Also, it can use an eigenbeam-space division multiplexing technique for efficient transmission. However, in time-varying environments, we may have performance degradation because of a channel change during the time interval between multi-user MIMO parameter determination and actual transmission. In this paper, on the basis of time-varying indoor measurements, we show Doppler spectra and average bit error rates (BERs). We also show that time-varying channels seriously degrade the BER performance., The Institute of Electronics, Information and Communication Engineers, Japanese

Evaluation of Transmission Power in an Uplink Virtual MIMO System
ITO Tatsuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 110, 127, 125, 130, 08 Jul. 2010
In future cellular radio, we need to transmit signals in a higher frequency band to accommodate a wider frequency bandwidth. The higher a frequency band is, the larger the propagation loss is. Also, a wider frequency bandwidth requires higher transmission power. For an uplink channel, however, the transmission power is limited because the power is supplied by the terminal battery. Thus, we will encounter a difficulty in sending uplink signals. Virtual MIMO-based cooperative communication is expected to be a key technology to solve this problem. In this paper, we clarify bit error rate and packet error rate performances on the basis of a realistic propagation channel model. We evaluate the required transmission power. It has been shown that the virtual MIMO system requires lower transmission power than the conventional SIMO scheme., 一般社団法人電子情報通信学会, Japanese

Generalized Block Diagonalization for Multiuser MIMO Downlink
SADA Tomoki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 110, 127, 161, 166, 08 Jul. 2010
In the downlink(broadcast channel)of multiuser MIMO systems, we need to suppress the inter-user interference(IUI). Block diagonalization(BD)which achieves perfect nulling is noted as an effective solution. In addition, imperfect block diagonalization(IBD)has been proposed previously as one of the solutions. The IBD can obtain transmit diversity gain by partial nulling. In this paper, we unify approaches of BD and IBD into generalized BD(GBD). In the paper, the BER performance of the GBD is evaluated by computer simulations., 一般社団法人電子情報通信学会, Japanese

Prevention of False Detection due to Grating Lobes in Estimating Pedestrian Direction Using a Vehicle-Mounted Array Antenna
NOBA Toshihiro, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 110, 1, 47, 51, 02 Apr. 2010
Some techniques using intelligent transport systems have been studied to prevent traffic accidents whose victims are a pedestrian. We have studied a scheme that informs a driver of a pedestrian's position using an electromagnetic wave radiated from the pedestrian's RFID tag. Although the direction-of-arrival (DOA) of a direct wave indicates the direction of the pedestrian, it is, however, difficult to estimate the DOA under multipath fading environments. Therefore, we have used a simple technique we proposed for DOA estimation. Using multiple antennas with the spacing of 1.5 wavelengths, we receive signals that experience different fading due to vehicle motion. If we beamform towards the direction of the direct wave, we can expect to compute the maximum average power because its signal is the largest and the multipath components are reduced by the array. Using received horizontally-polarized signals, we then beamform towards multiple directions, and the direction that gives the maximum average power indicates the direction of the pedestrian. Since the antenna spacing is larger than a half wavelength, we have grating lobes and may have false detections. In this paper, we propose a scheme to cope with the grating lobe problem., 一般社団法人電子情報通信学会, Japanese

B-5-59 Imperfect Block Diagonalization with Eigenvector Selection for Multiuser MIMO Downlink
Sada Tomoki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2010, 1, 491, 491, 02 Mar. 2010
The Institute of Electronics, Information and Communication Engineers, Japanese

B-5-34 An Approximation to Optimum Trasmit Beamforming in an Interactive Wireless Relay
MATSUYA Sakiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 2010, 1, 466, 466, 02 Mar. 2010
一般社団法人電子情報通信学会, Japanese

B-5-69 Spectrum Reduction Scheme for Multi-carrier Transmission under EMI Environments
Nishimoto H, Hirai H, Taira A, Kubo H, Nishimura T, Ohgane T, Ogawa Y, Proceedings of the IEICE General Conference, 2010, 1, 501, 501, 02 Mar. 2010
一般社団法人電子情報通信学会, Japanese

Interference Reduction Using Smart Antennas under OFDM Wireless LAN Environments
NOBA Toshihiro, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 109, 440, 29, 34, 24 Feb. 2010
Information transmission between a controller and a machine is essential for reliable factory automation. To help facilitate this, wireless communication is useful in the building of flexible factory environments because it does not need cables. The wireless system can employ an OFDM LAN technique. However, in a case where a plurality of communication systems are used in a neighborhood, we may have mutual interference among them. This paper describes a smart antenna for the interference reduction. We examine two weight control schemes: one is based on channel estimation, and the other is the SMI algorithm. We show cumulative distributions of SINR and average BERs of the smart antenna., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of Blind Detection in PTS-OFDM
SHIBATA Koji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 440, 427, 432, 24 Feb. 2010
OFDM has a problem of high peak to average power ratio (PAPR) whereas it is tolerant to the frequency selective fading. As a countermeasure for the high PAPR problem, partial transmit sequence (PTS) giving different phase rotation to segmented blocks has been proposed. However, PTS requires side information on the phase rotation. Previously, we proposed a simple blind detection based on the M-algorithm with very low complexity. The blind detection performance is highly affected by phase rotation candidates. In this paper, we propose the search technique of the proper phase rotation for blind detection. Also, we examine the impact of channel estimation error and signal distortion on the blind detection performance., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of FDE using a Tri-diagonalizing Approach
SAITO Keisuke, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 440, 443, 448, 24 Feb. 2010
Frequency-domain equalization (FDE) and frequency-domain turbo equalization (FDTE) based on iterative decoding have been studied for suppressing inter-symbol interference (ISI) due to frequency selective fading in single carrier systems. When a high-mobility terminal is assumed in the system, ISI reduction performance of FDE degrades since cyclicity of the channel matrix is lost. To solve this problem, we have proposed a channel approximation and tri-diagonalizing approach to FDE and FDTE without strict calculation and ascertained the validity of our proposal by computer simulations. As a realistic scenario, in this paper, we introduce channel estimation and evaluate the impact of the channel estimation error on the equalizing performance., 一般社団法人電子情報通信学会, Japanese

Performance of a MIMO-OFDM eigenbeamforming system in a correlated channel
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka, APSIPA ASC 2010 - Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, 2010

Transmit Beamforming in an Interactive Wireless Relay System
MATSUYA Sakiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 305, 25, 30, 19 Nov. 2009
Recently, wireless relay systems have been investigated to achieve a flexible network for ubiquitous communication. Network coding that encodes the packets using XOR in the relay node is expected to reduce the number of transmission packets and to improve throughput performance in the network. In this paper, we propose the transmit beamforming technique when the relay node has two or more antenna elements in the interactive wireless relay system and evaluate the packet error rate and throughput performance., 一般社団法人電子情報通信学会, Japanese

Characteristic Evaluation of a Virtual MIMO System in an Uplink Channel in Dynamic Fading Environments
ITO Tatsuya, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 109, 305, 73, 78, 19 Nov. 2009
A higher frequency band is considered to be used for future mobile communications for broadband transmission. However, propagation loss increases at a higher frequency band. The transmission will be difficult in an uplink channel because of limited transmit power of terminals. To solve the problem, cooperative communication has drawn attention. We have proposed a virtual MIMO system where neighboring terminals cooperate each other and form transmit beams as a distributed antenna system. In this paper, we examine frequency offset estimation performance and BER versus transmit power in dynamic fading environments. It has been clarified that the advantage of the virtual MIMO system decreases in dynamic fading environments. The reason for this is considered to be that transmit parameters cannot be determined properly because the channel at transmission time is not obtained exactly., 一般社団法人電子情報通信学会, Japanese

Multi-stream Transmission with Imperfect Block Diagonalization for Multiuser MIMO Downlink
SADA Tomoki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 229, 37, 42, 08 Oct. 2009
In the downlink (broadcast channel) of the multiuser MIMO system, suppression of inter-user interference (IUI) is an important issue to be solved. Due to the limitated antenna resources, it is difficult to implement the IUI cancellation at the terminal side. Thus, reduction of undesired radiation by a certain beam-control is preferable. The imperfect block diagonalization (IBD) has been proposed previously as one of the solutions. In the paper, we extend the IBD to be capable of multi-stream transmission per user and evaluate the BER performance using computer simulations., 一般社団法人電子情報通信学会, Japanese

Hardware Development of a MIMO Pseudo E-SDM System and Real-time Channel Emulator
Webber Julian, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings : APSIPA ASC 2009 : Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference, 684, 687, 04 Oct. 2009
APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference. 4-7 October 2009. Sapporo, Japan. Poster session: Signal Processing and Implementations in Communications (6 October 2009)., Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference, International Organizing Committee, English

B-5-49 Multi-stream Transmission in IBD Scheme for Multiuser MIMO Downlink
Sada Tomoki, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2009, 1, 398, 398, 01 Sep. 2009
一般社団法人電子情報通信学会, Japanese

B-5-50 Virtual MIMO System in Dynamic Fading Environments
Ito Tatsuya, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2009, 1, 399, 399, 01 Sep. 2009
一般社団法人電子情報通信学会, Japanese

B-5-55 A Study on Trasmit Beamforming in an Interactive Wireless Relay
MATSUYA Sakiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 2009, 1, 404, 404, 01 Sep. 2009
一般社団法人電子情報通信学会, Japanese

B-5-62 A Blind Detection of Side Information in PTS OFDM with a Simplified Search Algorithm
Shibata Koji, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2009, 1, 411, 411, 01 Sep. 2009
一般社団法人電子情報通信学会, Japanese

B-5-88 Improving of Tri-diagonal Matrix Approximation for FDTE in Fast Fading Environment
Saito Keisuke, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2009, 1, 437, 437, 01 Sep. 2009
一般社団法人電子情報通信学会, Japanese

An improved blind detection of side information in PTS OFDM
SHIBATA Koji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 130, 125, 130, 09 Jul. 2009
OFDM has a problem of high peak to average power ratio (PAPR) whereas it is tolerant to the frequency selective fading. As a countermeasure for the high PAPR problem, partial transmit sequence (PTS) giving different phase rotation to segmented blocks has been proposed. However, PTS requires side information on the phase rotation. Previously, we proposed a simple blind detection based on the M-algorithm with very low complexity. However, some degradation has been observed when the constraint length of the convolutional code is long. In the paper, as the countermeasure we evaluate the case with two survivor paths in M-algorithm in addition to the bi-directional search., 一般社団法人電子情報通信学会, Japanese

Tri-diagonalizing Approach on FDE in a Fast Fading Environment
SAITO Keisuke, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 109, 130, 119, 124, 09 Jul. 2009
Frequency-domain equalization (FDE) and frequency-domain turbo equalization (FDTE) based on iterative decoding have been studied for suppressing inter-symbol interference (ISI) due to frequency selective fading in single carrier systems. When a high-mobility terminal is assumed in the system, ISI reduction performance of FDE degrades since cyclicity of the channel matrix is lost. To solve this problem, we propose a tri-diagonalizing approach to FDE and FDTE without strict calculation and evaluate our proposal by computer simulations., 一般社団法人電子情報通信学会, Japanese

A Basic Study on Pedestrian Direction Estimation Using a Vehicle-Mounted Array Antenna
NOBA Toshihiro, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, TANAKA Makoto, SASAKI Kunihiko, IEICE technical report, 109, 117, 177, 182, 01 Jul. 2009
Some techniques using intelligent transport systems have been studied to prevent traffic accidents whose victims are a pedestrian. We have studied a scheme that informs a driver of a pedestrian's position using an electromagnetic wave radiated from the pedestrian's RFID tag. Although the direction-of-arrival (DOA) of a direct wave indicates the direction of the pedestrian, it is, however, difficult to estimate the DOA under multipath fading environments. This paper proposes a simple technique for DOA estimation. Using multiple antennas, we receive signals that experience different fading due to vehicle motion. If we beamform towards the direction of the direct wave, we can expect to compute the maximum average power because its signal is the largest and the multipath components are reduced by the array. Using the received data, we then beamform towards multiple directions, and the direction that gives the maximum average power indicates the direction of the pedestrian. Conducting computer simulations, we show the performance of the proposed scheme., 一般社団法人電子情報通信学会, Japanese

BP-2-6 Multi-Antenna Techniques for LTE-Advanced
Ohgane Takeo, Taoka Hidekazu, Hoshino Masayuki, Seki Hiroyuki, Kakura Yoshikazu, Proceedings of the IEICE General Conference, 2009, 1, "SS, 29"-"SS-30", 04 Mar. 2009
一般社団法人電子情報通信学会, Japanese

BI-2-6 MIMO Technologies in Mobile Radio
Ohgane Takeo, Proceedings of the IEICE General Conference, 2009, 1, "SS, 117"-"SS-118", 04 Mar. 2009
一般社団法人電子情報通信学会, Japanese

B-5-70 A Study on Blind Estimation of Side Information in PTS OFDM
Shibata Koji, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2009, 1, 503, 503, 04 Mar. 2009
一般社団法人電子情報通信学会, Japanese

B-5-56 Amplitude Correction for MMSE Receiver Outputs
Nishimoto Hiroshi, Sogabe Yasushi, Shibuya Akihiro, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2009, 1, 489, 489, 04 Mar. 2009
一般社団法人電子情報通信学会, Japanese

B-5-51 Tri-diagonal Matrix Approximation for Frequency Domain Turbo Equalization in Fast Fading Environment
Saito Keisuke, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2009, 1, 484, 484, 04 Mar. 2009
一般社団法人電子情報通信学会, Japanese

A Study on Transmit Power in an Uplink Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, IEICE technical report, 108, 445, 65, 70, 25 Feb. 2009
A higher frequency band is considered to be used for future mobile communications. However, reliable transmission may not be possible in an uplink channel because of limited transmit power of terminals. We can improve uplink transmission performance using a virtual antenna array which is formed by multiple terminals cooperating with each other. However, because we have neglected the power for sharing data among the terminals in our previous studies, a fair comparison with a non-cooperating system has not been done. In this paper, we consider total transmit power required for a virtual MIMO system and compare the characteristic with that of non-cooperating system in variety of propagation environments., 一般社団法人電子情報通信学会, Japanese

A Study on Complexity Reduction of HARQ with Frequency Domain Turbo Equalization using Chase Combining
QIN Fei, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 108, 391, 201, 205, 15 Jan. 2009
Frequency domain turbo equalization with soft canceller is a powerful way to reduce the inter-symbol interference in a frequency selective fading channel for single-carrier systems. When applying the frequency domain turbo equalization to a Type-I HARQ system, chase combining with parallel turbo-equalizers using multiple received packets achieves a significant improvement of throughput performance at a cost of heavy load. In the paper, the performance of the complexity reduction method previously proposed by the authors is analyzed. And, improved methods for complexity reduction is proposed., 一般社団法人電子情報通信学会, Japanese

Hardware development of a MIMO pseudo E-SDM system and real-time channel emulator
Webber, Julian, Nishimura, Toshihiko, Ohgane, Takeo, Ogawa, Yasutaka, APSIPA ASC 2009 - Asia-Pacific Signal and Information Processing Association 2009 Annual Summit and Conference, 2009

B-1-228 A Basic Study on Pedestrian Location Detection Using a Vehicle-Mounted Array Antenna
Noba Toshihiro, Ogawa Yasutaka, Nishimura Toshiihko, Ohgane Takeo, Tanaka Makoto, Sasaki Kunihiko, Proceedings of the IEICE General Conference, 228, 228, 2009
一般社団法人電子情報通信学会, Japanese

B-1-209 A Study on DOA Estimation by Using a UWB Signal
Morikawa Hiroaki, Nishimura Toshihiko, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 209, 209, 2009
一般社団法人電子情報通信学会, Japanese

A study on blind esimation of side information in PTS OFDM
SHIBATA Koji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 108, 249, 7, 12, 15 Oct. 2008
OFDM has a problem of high peak to average power ratio (PAPR) whereas it is tolerant to the frequency selective fading. As a countermeasure for high PAPR problem, partial transmit sequence (PTS) giving different phase rotation to segmented blocks has been proposed. However, PTS requires inverse phase rotation at the receiver side for corrent detection. Thus, an extra subchannel for side information transmission is needed. in the paper, a blind detection based on the parallel trellis decoding under the use of a convolutional code is proposed. And, its high performance has been confirmed by computer simulations., 一般社団法人電子情報通信学会, Japanese

BS-1-2 A Study on the Feedback of Transmit Weights Using a Codebook in a Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2008, 1, "S, 3"-"S-4", 02 Sep. 2008
一般社団法人電子情報通信学会, Japanese

B-5-58 Performance Evaluation of HARQ with Frequency Domain Turbo Equalization
QIN Fei, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 2008, 1, 371, 371, 02 Sep. 2008
一般社団法人電子情報通信学会, Japanese

Performance of Multiuser MIMO Systems Employing the Block-Diagonalization Scheme and the E-SDM Technique in Actual Time-Varying Fading Environments
BUI Huu Phu, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 108, 188, 19, 24, 27 Aug. 2008
In the paper, we present our measurement campaigns in a typical meeting room to get multiuser multiple-input multiple-output (MIMO) channels. Based on the data, the performance of multiuser MIMO systems employing the block-diagonalization (BD) scheme and the eigenbeam-space division multiplexing (E-SDM) technique for downlink transmission is evaluated in actual time-varying fading environments. Simulation results show that due to a channel change during the time interval between the transmit weight matrix determination and the actual downlink data transmission, the performance is much degraded because of inter-user and inter-substream interference. Here, we propose two methods of channel extrapolation, linear extrapolation and second-order extrapolation, to compensate for the channel change. Simulation results show that applying the proposed methods to the systems, much better performance can be obtained., 一般社団法人電子情報通信学会, English

A Study on the Feedback Amount Reduction of Frequency Offset and Transmit Weight in a Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 108, 188, 25, 30, 27 Aug. 2008
A higher frequency band is considered to be used for future mobile communications. However, reliable transmission may not be possible in an uplink channel because of limited transmit power of terminals. We can improve uplink transmission performance using a virtual antenna array which is formed by multiple terminals cooperating with each other. However, in this system, the terminals need information about transmit weight, frequency offset, and transmit power ratio from a base station. The feedback of the information from a base station limits downlink transmission. In this paper, we propose a codebook for transmit weight, and quantization of frequency offset and transmit power ratio. We examine the impact of them on the bit error rate performance., 一般社団法人電子情報通信学会, Japanese

A Study on HARQ with Frequency Domain Turbo Equalization
QIN Fei, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 108, 188, 151, 156, 27 Aug. 2008
Frequency domain turbo equalization with soft canceller is a powerful way to reduce the inter-symbol interference in a frequency selective fading channel for single-carrier systems. In the paper, the frequency domain turbo equalization is applied to an HARQ system and its throughput performance is confirmed. In addition, several simplified methods of chase combining for multiple received packets is proposed. The computer simulation results show that the performance degradation due to simplifying is not significant., 一般社団法人電子情報通信学会, Japanese

Considerations on MIMO Channel Characteristics and Performance of Spatial Multiplexing in Time-Varying Fading Environments
BUI Huu Phu, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 108, 148, 129, 134, 16 Jul. 2008
The main contribution of the paper is to investigate channel charateristics based on measured data in a typical meeting room and to evaluate the performance of MIMO systems using an eigenbeam-space division multiplexing (E-SDM) technique in actual time-varying fading environments. Results based on the measured channel data show that channel auto-correlation and Doppler spectrum are much dependent not only on the direction of terminal motion, but also on the antenna configuration. Even in the non-line-of-sight environment, observed Doppler spectrum is quite different from the theoretical U-shaped Jakes one. In addition, it has been also shown that a channel change during the time interval between the transmit weight matrix determination and the actual data transmission can degrade the performance of MIMO E-SDM systems., 一般社団法人電子情報通信学会, English

Blind Iterative Decoding in Bit-Interleaved Coded DPSK
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 107, 518, 193, 198, 05 Mar. 2008
When the transmitter maps a bit-interleaved coded sequence into DPSK symbols, turbo (iterative) decoding is applicable at the receiver by regarding a differential encoder in DPSK as an inner encoder, i.e., serial concatenation of two encoders. In this paper, we examine blind iterative decoding in a bit-interleaved coded DPSK system. We also propose a blind channel estimation scheme based on decision feedback because coherent detection is required for the iterative decoding. The result obtained by computer simulations shows that performance of the iterative decoding significantly outperforms that of coherent PSK with perfect CSI. In addition, it is demonstrated that the proposed channel estimation scheme provides the performance approaching to that of the perfect CSI case by 0.1dB and 0.9dB in no fading and dynamic fading environments, respectively, at BLER of 10^<-2>., 一般社団法人電子情報通信学会, Japanese

Imperfect Block Diagonalization for Downlink Multiuser MIMO Systems
KATO Shohei, NISHIMOTO Hiroshi, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, IEICE technical report, 107, 518, 329, 334, 05 Mar. 2008
Recently, a multiuser MIMO system has attracted much attention. In the downlink of the multiuser MIMO system, since the base station simultaneously transmits signals to terminals, there is inter-user interference (IUI) at each terminal. Block diagonalization, which can achieve perfect IUI supression, has been extensively studied to solve the issue. However, with the scheme we cannot obtain sufficient diversity gain due to the null steering at the base station. In this paper, we propose imperfect block diagonalization based on maximum eigenvectors of users and Gram-Schmidt orthonormalization, and its error rate performance is evaluated using computer simulation. The result shows that, despite its low complexity, the proposed scheme provides excellent performance, especially in many user environments., 一般社団法人電子情報通信学会, Japanese

A study on channel prediction and decision-feedback assisted channel tracking for IEEE802.16e based OFDM system
KIM Sang-Woo, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 107, 440, 85, 90, 17 Jan. 2008
OFDM is an attractive system for high spectral efficiency and capability of multipath fading compensation. In high-speed fading environments, however, channel tracking during the data period becomes a substantial technique to maintain good BER performance since channel change from the initial estimate using preamble symbols cannot be ignored. In this paper, we focus on the decision feedback channel tracking and propose a way to generate more accurate replicas by switching the decoder output based on a property of concatenated codes. In addition, we introduce a linear prediction method with two different techniques for the estimate of prediction coefficients. The simulation results show the effectiveness of these proposed methods under an IEEE 802.16e-OFDM model with 250Hz and higher Doppler frequency., 一般社団法人電子情報通信学会, Japanese

Design a real-time IEEE 802.11n MIMO-OFDM system with PE-SDM beamforming
Julian, Koden technical journal, 24, 8, 14, 2008
光電製作所, English

Design of a Real-time IEEE 802.11n MIMO-OFDM System with PE-SDM Beamforming
WEBBER Julian, OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka, 光電技報, 24, 2008

A Received Block Division Technique with SC/MMSE Turbo Equalization under Fast Fading Environments
KAMBARA Keiichi, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 107, 402, 37, 42, 13 Dec. 2007
Frequency-domain equalization (FDE) has been studied as a very simple countermeasure against frequency selective fading in a single carrier transmission system. In a fast fading environment, however, the equalization performance degrades since periodicity of the channel within an FDE block is lost. Therefore, we have proposed a method dividing a received data block into multiple subblocks to decrease the channel transition within the block in such an environment. In this method, the performance is degraded by inaccuracies of pseudo CP processing, which is introduced to satisfy periodicity in each subblock. In this paper, we study the application of frequency-domain turbo equalization (FDTE) to subblock processing for improving the accuracy of pseudo CP. The simulation results show that FDTE with subblock processing yields remarkable performance improvements., 一般社団法人電子情報通信学会, Japanese

A Study on Uplink Weights Compensating Terminal Frequency Offsets in a Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, IEICE technical report, 107, 305, 31, 36, 01 Nov. 2007
Recently, a virtual antenna array, which is formed by multiple terminals cooperating each other, has attracted attention because it can potentially improve uplink capacity in high-frequency-band communications. However, since it is difficult in practice to accurately synchronize carrier frequencies at the terminals, performance is degraded due to frequency offsets. In this paper, we propose a method to estimate frequency offsets and to conpensate them at the terminals. Also, this paper describes a receive weight tracking scheme by the RLS algorithm at a basestation. Then, we evaluate the BER performance by computer simulations. The simulation results show performance improvements by applying these techniques., 一般社団法人電子情報通信学会, Japanese

Channel Estimation with Ordered Interference Cancellation for a MIMO Receiver Using Iterative Equalization and Decoding
HIGASHINAKA Masatsugu, KUBO Hiroshi, SHIBUYA Akihiro, OKAZAKI Akihiro, OGAWA Yasutata, OHGANE Takeo, NISHIMURA Toshihiko, IEICE technical report, 107, 262, 1, 6, 11 Oct. 2007
This paper proposes a channel estimation method with ordered interference cancellation for a MIMO receiver using iterative equalization and decoding. In the iterative receiver, channel estimation can be performed in every iteration by using symbol estimates composed of extrinsic information from a soft-output decoder. In the MIMO case, however, data sequences transmitted from each transmit antenna are not always applicable to the iterative channel estimation because the transmitted data sequences may be not suitable for the channel estimation. The proposed channel estimation method performs ordered interference cancellation and then estimates the channel state information for a residual stream, reffering to a decoder output. Computer simulation confirms that the proposed method has excellent frame error rate performance., 一般社団法人電子情報通信学会, Japanese

Experimental Evaluations of E-SDM Transmission with Adaptive Modulation Using a Testbed
NAITO A, NISHIMURA T, OHGANE T, OGAWA Y, IEICE technical report, 107, 262, 19, 24, 11 Oct. 2007
We can realize high-speed communications with MIMO systems that have multiple antennas at both transmitter and receiver. For a downlink channel in a MIMO system, we apply E-SDM using adaptive modulation in which communication speed is changed according to the channel condition. In this case, assuming packet transmission, we apply a maximum throughput criterion for the adaptive modulation. In this paper, we evaluate the throughput performance of E-SDM transmission with adaptive modulation by using an indoor testbed. Because computation load with conventional adaptive modulation is heavy, it is reduced by simplification. Additionally, we show that linear extrapolation that compensates errors caused by channel fluctuation works in dynamic fading environments., 一般社団法人電子情報通信学会, Japanese

B-5-25 An Effective Channel Estimation Scheme Using Space-Time Windowing in Pseudo Eigenbeam Transmission
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 2007, 1, 439, 439, 07 Mar. 2007
一般社団法人電子情報通信学会, Japanese

Fundamental Studies on Transmit Beamforming with Virtual Antenna Arrays
OGAWA Kenta, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, IEICE technical report, 106, 555, 65, 68, 28 Feb. 2007
Recently, the virtual antenna array, which is formed by multiple terminals cooperating each other, has attracted attention because it can potentially improve capacity in high-frequency-band communications. However, since it is difficult in practice to accurately synchronize the terminals, performance may be affected by phase and frequency offsets, which are caused by the imperfect synchronization. In this paper, we evaluate effects of the offsets and channel estimation errors on the system performance by computer simulations. The results show that degradation of performance can be reduced by using the equivalent channel, which includes both the actual channel and offsets, in processing at the receiver, and that performance in multi-beam transmission is more affected by the frequency offset compared with that in single-beam transmission., 一般社団法人電子情報通信学会, Japanese

Improvement of a Received Block Division Technique for MMSE-FDE under Fast Fading Environments
KAMBARA Keiichi, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report, 106, 480, 7, 12, 26 Jan. 2007
Frequency domain equalization (FDE) has been studied for preventing performance degradation due to frequency selective fading in single carrier transmission. In fast fading environments, however, another problem occurs since cyclicity in the FDE block is lost. Thus, we have proposed subblock processing at the receiver side with pseudo cyclic prefix (CP) generation. The performance highly depends on the CP accuracy. Therefore, here, we apply a higher order interpolation method for more accurate channel estimation. In addition, overlapped subblock processing is used to reduce an effect of degradation in pseudo CP accuracy. The simulation results show performance improvements by applying these techniques to the subblock processing., 一般社団法人電子情報通信学会, Japanese

A Study on Improvement of Channel Estimation Accuracy in Pseudo Eigenbeam Space Division Multiplexing
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 480, 67, 72, 26 Jan. 2007
In a MIMO system with space-frequency domain beamforming under frequency selective fading scenarios, a pseudo eigenvector decomposition has been proposed to reduce the calculation load at the transmitter and to maintain frequency continuity of the effective channel observed at the receiver. It has been reported that a pseudo eigenbeam space division multiplexing (PE-SDM) technique can provide almost the same or better performance compared with eigenbeam space division multiplexing when the receiver employs a simple channel estimator exploiting pseudo-eigenvector properties. In this paper, focusing on the calculating process of pseudo eigenvectors, we propose a new scheme improving the accuracy of the effective channel estimates. The simulation results show that the accuracy in the PE-SDM is improved by combining the proposed scheme with the conventional one., 一般社団法人電子情報通信学会, Japanese

A Study on Reduction Schemes of Feedback Amount in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 106, 480, 73, 78, 26 Jan. 2007
In a multiple-input multiple-output system for OFDM (MIMO-OFDM), eigenbeam-space division multiplexing (E-SDM) which is also called a singular value decomposition (SVD) algorithm can provide maximum throughput in MIMO channels when channel state information (CSI) or transmit weight matrix is available at the transmitter. We have proposed a technique that only dominant time-domain CSI is fed back in order to reduce the amount of feedback. In this paper, we compare the proposed method to the scheme which feeds back the transmit weight matrix with a codebook., 一般社団法人電子情報通信学会, Japanese

B-5-109 A Study on Channel Interpolation for Subblock Processing Using MMSE-FDE under Fast Fading Environments
Kambara Keiichi, Nishimoto Hiroshi, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 523, 523, 2007
The Institute of Electronics, Information and Communication Engineers, Japanese

B-1-201 Uplink Weight Determination Compensating Terminal Frequency Offsets in a Virtual MIMO System
SAITO Yuta, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, Proceedings of the Society Conference of IEICE, 201, 201, 2007
一般社団法人電子情報通信学会, Japanese

B-1-202 Downlink Weights for Multiuser MIMO Systems Using the Gram-Schmidt Orthogonalization
Kato Shohei, Nishimoto Hiroshi, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 202, 202, 2007
一般社団法人電子情報通信学会, Japanese

B-5-15 A study on channel tracking with decision feedback in WiMAX-OFDM systems
Kim Sang-Woo, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 337, 337, 2007
一般社団法人電子情報通信学会, Japanese

Effects of Channel Prediction on MIMO E-SDM System Performance in Actual Time-Varying Fading Environments
BUI Huu Phu, NISHIMURA Toshihiko, NISHIMOTO Hiroshi, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report, 106, 395, 97, 104, 22 Nov. 2006
In time-varying fading environments, a channel prediction method should be used to reduce channel errors due to the channel changes between the transmit weight matrix determination time and the actual data transmission time, so that the performance of MIMO E-SDM (Eigenbeam-Space Division Multiplexing) system can be improved. Here, we present an experimental measurement setup to evaluate the performance in actual environments. Based on the measured data, simulation results show that by using our proposed prediction methods much better performance can be obtained in both actual line-of-sight (LOS) and non-LOS (NLOS) communications environments. We can also see that the performance in LOS environments is better than that in NLOS ones., 一般社団法人電子情報通信学会, English

A Received Block Division Technique for MMSE-FDE under Fast Fading Environments
KAMBARA Keiichi, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report, 106, 305, 95, 100, 12 Oct. 2006
Frequency domain equalization (FDE) has been studied for suppressing inter-symbol interference (ISI) due to frequency selective fading in single carrier systems. When a high-mobility terminal is assumed in the system, channel transition within a FFT block can not be ignored. Then, ISI reduction performance of FDE degrades since cyclicity of the channel matrix is lost. Here, we propose a method dividing a received data block into multiple subblocks to decrease the channel transition within the FFT block in fast fading environments. In addition, we propose a method generating pseudo cyclic prefix to satisfy periodicity of the received signal in each subblock., 一般社団法人電子情報通信学会, Japanese

B-1-217 Performance of MIMO-OFDM Pseudo Eigenbeam Transmission in an Indoor Propagation Environment
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 2006, 1, 217, 217, 07 Sep. 2006
周波数選択性フェージング環境下のMIMOシステムでは,各周波数において固有ビーム形成を行うことで最適伝送を実現できるが[1],周波数毎の固有ウェイトの算出は大きな計算負荷となり,周波数連続性のない送信ウェイトは受信側で観測される実効チャネルのインパルス応答に大きな遅延広がりを生じさせる.これらの問題を解決するため,筆者らは文献[2]において疑似固有ベクトル手法を提案し,これにより演算量削減,及び,実効チャネルの周波数連続性を実現できることを示した.本稿では.文献[3]の屋内伝搬実験に基づき,疑似固有ベクトルを用いるPE-SDM (Pseudo Eigenbeam-Space Division Multiplexing)について,実環境におけるMIMO-OFDM伝送特性を評価する., 一般社団法人電子情報通信学会, Japanese

B-5-9 Performance of E-SDM Single Carrier Transmission with MMSE-FDE and a Parallel Interference Canceller
ISHIDA Takahiro, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 2006, 1, 368, 368, 07 Sep. 2006
一般社団法人電子情報通信学会, Japanese

B-5-40 A study on multicode transmission with frequency domain equalization
Iwazaki Kiyoto, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2006, 1, 400, 400, 07 Sep. 2006
一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO-OFDM Pseudo Eigenbeam Space Division Multiplexing
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 223, 1, 6, 24 Aug. 2006
In a MIMO system with space-frequency domain beamforming under frequency selective fading scenarios, a pseudo eigenvector decomposition has been proposed to reduce the calculation load at the transmitter and to maintain frequency continuity of the effective channel observed at the receiver. It has been reported that pseudo eigenbeam space division multiplexing (PE-SDM) technique can provide almost the same or better performance compared with eigenbeam space division multiplexing (E-SDM) when the receiver employs a simple channel estimator exploiting pseudo-eigenvector properties. In this paper, under various multipath delay profiles, we evaluate performance of the PE-SDM in MIMO-OFDM with an interference canceller and compare it with E-SDM perfor-mance. The simulation results show that the accuracy of the estimated effective channel in the PE-SDM can be improved more under lower delay spread multipath environments, and that the receiver incorporating a parallel interference canceller can make the performance of the PE-SDM better than that of the E-SDM., 一般社団法人電子情報通信学会, Japanese

Performance of Frequency-Flat E-SDM (FFE-SDM) Single Carrier Transmission with MMSE-FDE Incorporating an Interference Canceller
ISHIDA Takahiro, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 223, 7, 12, 24 Aug. 2006
In frequency selective MIMO channels, frequency-flat E-SDM (FFE-SDM) with MMSE-FDE suffers from co-channel interference (CCI). Thus it has been shown that resource adaptation based on both inter-symbol interference and CCI measures gives good performance. In this paper, we apply a parallel interference canceller (PIC) to this system for reducing CCI effectively and evaluate performance with resource adaptation based on three criteria. In comparison with the conventional SDM, the results show that the FFE-SDM technique is more robust to fading correlation and that an eigenvalue criterion which can be easily calculated is practical., 一般社団法人電子情報通信学会, Japanese

A Study on Reduction of the Amount of CSI Feedback with Time-domain Channel in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 106, 168, 31, 36, 12 Jul. 2006
In a multiple-input multiple-output system for OFDM (MIMO-OFDM), eigenbeam-space division multiplexing (E-SDM) which is also called a singular value decomposition (SVD) algorithm can provide maximum throughput in the MIMO channel when channel state information (CSI) is available at the transmitter. We have proposed reduction of the CSI feedback using the minimum mean square error method in the time domain, and clarified good bit error rate performance. In this paper, we propose a novel technique that only dominant time-domain CSI is fed back in order to reduce the amount of feedback compared to the conventional scheme., 一般社団法人電子情報通信学会, Japanese

Pseudo Eigenbeam SDM with MMSE-FDE for Single Carrier Transmission
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 168, 61, 66, 12 Jul. 2006
In a MIMO system with space-frequency domain beamforming under frequency selective fading scenarios, a pseudo eigenvector decomposition has been proposed to reduce the calculation load at the transmitter and maintain frequency continuity of the effective channel observed at the receiver. In this paper, we evaluate the performance of the pseudo E-SDM (PE-SDM) transmission in MIMO single carrier systems with MMSE-FDE, and compare three substream quality measures for transmit resource control and two encoding schemes. The simulation results show that difference among the three criteria becomes smaller as the number of antennas increases. Moreover, the scheme, in which each data sequence is encoded and interleaved over all substreams, makes the difference smaller so that a simple resource control is practically applicable., 一般社団法人電子情報通信学会, Japanese

A fundamental study on multicode transmission with frequency domain equalization
IWAZAKI Kiyoto, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 168, 73, 78, 12 Jul. 2006
In frequency-selective channels, the performance of a direct sequence code division multiplexing (DS-CDM) system is severely degraded by inter-code interference since code orthogonality is no longer satisfied. However, the inter-code interference can be suppressed by frequency domain equalization (FDE). On the other hand, multicode transmission in DS-CDM causes an increase of peak-to-average-power-ratio (PAPR). For PAPR reduction, it is known that selection or multiplexed symbol combination from a limited group is effective. Here, side information on the selection must be transmitted. In this paper, we propose to use the side information as a code redundancy and to apply turbo type decoding. As the first step, the performance of multicode transmission with a simple even parity is evaluated. The resutls show that, using turbo type decoding and MMSE-FDE in a frequency selective channel, the obtained gain at FER of 10^<-3> is about 3dB., 一般社団法人電子情報通信学会, Japanese

Pseudo Eigenbeam-Space Division Multiplexing in Frequency Selective Fading Environments
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 106, 119, 125, 130, 15 Jun. 2006
In frequency selective MIMO channels, the optimum transmission is achieved by beamforming based on eigenvectors (i.e., E-SDM) at each frequency point. However, the calculation load of eigenvalue decomposition at the transmitter increases in proportion to the number of frequency points. In addition, frequency-independent eigenvectors enlarge delay spread of the effective channel observed at the receiver. In this paper, we propose pseudo eigenvectors for the purpose of maintaining frequency continuity of the effective channel and reducing the calculation load at the transmitter. First, we demonstrate that pseudo eigenvectors decrease delay spread of effective channels. Next, the performance of the pseudo E-SDM (PE-SDM) transmission in MIMO-OFDM systems is evaluated. The simulation results show that PE-SDM provides almost the same or better performance compared with E-SDM when an estimated effective channel is used to detect the substreams at the receiver., 一般社団法人電子情報通信学会, Japanese

A Study on Reduction of the Amount of Channel State Information Feedback in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report, 106, 25, 37, 42, 14 Apr. 2006
MIMO space division multiplexing in an OFDM system (MIMO-OFDM) can achive high-data-rate transmission without additional frequency spectra. Furthermore, eigenbeam-space division multiplexing (E-SDM) which is also called the singular value decomposition (SVD) algorithm can provide maximum throughput in the MIMO channel when channel state information (CSI) is available at the transmitter. When the uplink and downlink channels are not reciprocal as in a FDD system, we need to feed back the CSI from the receiver to the transmitter. However, capacity is limited because CSI feedback is needed for each subcarrier in an OFDM system. This paper proposes the feedback of the time-domain channel estimated using the minimum mean square error method. The proposed method can reduce the amount of feedback information, and reveals better bit error rate performance than the other schemes., 一般社団法人電子情報通信学会, Japanese

A Study on Eigenbeam-Space Division Multiplexing with MMSE-FDE
ISHIDA Takahiro, NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 106, 25, 55, 60, 14 Apr. 2006
In frequency selective multiple-input multiple-output (MIMO) channels, equalization for suppressing inter-symbol interference is necessary as well as spatial-demultiplexing. When MMSE frequency domain equalization (MMSE-FDE) is applied to a single carrier system in eigenbeam-space division multiplexing with frequency-flat transmit weights, resource adaptation based on the extended MIMO channel does not give expected performance due to not considering less detection capability of MMSE-FDE. In this paper, we propose two criteria and evaluate their performance compared with the conventional space division multiplexing transmission. The results show that a new criterion incorporating the amount of interference in the MMSE-FDE output gives better performance than the others., 一般社団法人電子情報通信学会, Japanese

B-5-76 Channel Prediction for an E-SDM System in Time-Varying Fading Environments
BUI Huu-Phu, OGAWA Yasutaka, OHGANE Takeo, NISHIMURA Toshihiko, Proceedings of the IEICE General Conference, 2006, 1, 428, 429, 08 Mar. 2006
The Institute of Electronics, Information and Communication Engineers, English

B-5-68 A Study on Reduction of the Amount of CSI Feedback in MIMO-OFDM Eigenbeam-Space Division Multiplexing Systems
OHWATARI Yusuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2006, 1, 420, 420, 08 Mar. 2006
一般社団法人電子情報通信学会, Japanese

B-5-97 An Estimation Method of Multiple User Uplink OFDMA Channels
MIYAZAWA Makoto, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2006, 1, 450, 450, 08 Mar. 2006
一般社団法人電子情報通信学会, Japanese

A-5-27 Performance Evaluation of MIMO-UWB Systems in Actual Propagation Environments
Takanashi Masaki, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2006, 141, 141, 08 Mar. 2006
一般社団法人電子情報通信学会, Japanese

A study on transmit-antenna selection for multiuser-MIMO uplink
OHKAWARA Junya, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 105, 559, 65, 70, 19 Jan. 2006
In this paper, we discuss methods of transmit-antenna selection for uplink multiuser MIMO-SDM systems. In multiuser MIMO-SDM systems, signal detection quality at a basestation is degraded by cochannel interference, and depends on the number of transmit antennas of each user. In this paper, we propose a novel method for antenna selection to increase diversity gain. The criterion of antenna selection is based on capacity using spatial filter output. Simulation results show that frame error rate performance in the multiuser MIMO-SDM systems is improved by the proposed method. In addition, we show the advantage of diversity gain to select the number of transmit antennas at each user., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO E-SDM Based on Indoor Measurement
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 105, 355, 127, 132, 13 Oct. 2005
A multiple input multiple output (MIMO) system in which multiple antennas are placed at both the transmitter and receiver end can potentially meet the growing demand for higher capacity in wireless communications. When information on the channel state is available at the transmitter end, eigenbeam-space division multiplexing (E-SDM) which can provide maximum throughput in the MIMO channel is more efficient technique in order to achieve higher speed transmission compared with the conventional space division multiplexing (SDM). This paper shows MIMO channel measurement campaigns conducted in indoor line-of-sight (LOS) and non line-of-sight (NLOS) environments. Using the measured data, we present the bit error rate performance of 2×2 and 4×4 E-SDM. The results shows that, E-SDM generally gives better performance than SDM, and LOS environments provide more excellent performance of E-SDM compared with NLOS ones. However, we can see that the performance of E-SDM in LOS environments strongly depends on the array configuration., 一般社団法人電子情報通信学会, Japanese

Experimental Evaluations of a Coded MIMO-OFDM System
OHWATARI Yusuke, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 105, 356, 61, 66, 13 Oct. 2005
MIMO space division multiplexing in an OFDM system (MIMO-OFDM) can achive high-data-rate transmission without inter-symbol interference in frequency selective fading channels. In a receiver, however, spatial filtering is needed to separate and detect transmitted signals because the signals sent from all the transmit antennas interfere each other. It has been reported that precise channel estimation is possible and the performance of MIMO-OFDM using MMSE-OSD is improved by an evaluation system experimentaly. In this paper, we introduce a coded MIMO-OFDM system in order to improve the performance. Also, we show the experimental results of performance of BER and FER., 一般社団法人電子情報通信学会, Japanese

B-5-24 Compensation of Time-variant Fading Channel Error for E-SDM in a TDD System
Phu Bui Huu, Ogawa Yasutaka, Ohgane Takeo, Nishimura Toshihiko, Proceedings of the Society Conference of IEICE, 2005, 1, 424, 424, 07 Sep. 2005
The Institute of Electronics, Information and Communication Engineers, English

B-5-31 Multi-user MIMO Systems for W-CDMA Uplink
TANAKA Toyohisa, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2005, 1, 431, 431, 07 Sep. 2005
一般社団法人電子情報通信学会, Japanese

BS-1-4 Performance Evaluation of MIMO Eigen-beam Space Division Multiplexing in Actual Environments
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2005, 1, "S, 7"-"S-8", 07 Sep. 2005
一般社団法人電子情報通信学会, Japanese

AS-1-10 Studies on MIMO-UWB-IR Systems using Frequency Domain Equalization
Takanashi Masaki, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 2005, "S, 19"-"S-20", 07 Sep. 2005
一般社団法人電子情報通信学会, Japanese

A study on transmit-antenna selection in Multiuser-MIMO systems
OHKAWARA Junya, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 105, 121, 53, 58, 10 Jun. 2005
In this paper, we discuss effects of transmit-antenna selection for uplink multiuser MIMO-SDM systems. In multiuser MIMO-SDM systems, signal detection quality at a basestation is degraded by cochannel interference and depends on the number of transmit antennas. To reduce cochannel interference, we consider limiting the number of transmit-antennas and antenna selection at each or target mobile station. Computer simulation results show that frame error rate performance in multiuser MIMO-SDM systems is improed by transmit-antena selection., 一般社団法人電子情報通信学会, Japanese

Experimental evaluation on E-SDM with channel estimation error compensation
HATA Y, NISHIMURA T, OHGANE T, OGAWA Y, Technical report of IEICE. RCS, 105, 121, 65, 70, 10 Jun. 2005
Applying E-SDM system is evaluated for a TDD uplink in MIMO (Multiple-Input Multiple-Output) channels when a channel response matrix is known at a transmitter. If time difference between transmit weight calculation from channel information at a transmitter and actual transmission is large, performance of E-SDM degrades because channel orthogonality is not kept. In this study, indoor experiments of E-SDM are done using fading simulators to evaluate the channel estimation error compensation by the first order extrapolation, which has been proposed. Furthermore, simplification of transmission resource control and reduction of calculation load are proposed. Experimental results show that the channel estimation error compensation by the first order extrapolation is very effective and improves BER performance., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO-SDM Using a Tripole Antenna Based on Indoor Channel Measurements
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 105, 121, 71, 76, 10 Jun. 2005
Recently a MIMO system, which promises very high-speed data transmission, has attracted great attention to wireless communications. In multipath-rich environments, it is considered that strong cross-polarization components also arrive at a receiver. We measured 3×3 MIMO channels in a multipath-rich room using tripole antennas. The tripole antenna is composed of three orthogonal omni-directional antennas. It is shown that the tripole antennas give lower fading correlations. However, we cannot find clear differences of the performance in array configurations., 一般社団法人電子情報通信学会, Japanese

B-1-244 Performance Comparison of MIMO Spatial Multiplexing on Various Array Configurations in Actual Propagation Environments
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2005, 1, 244, 244, 07 Mar. 2005
一般社団法人電子情報通信学会, Japanese

B-5-84 A study on scaling of likelihood values on MIMO-OFDM systems
HOSHINO Masayuki, TAKAKUSAKI Keiji, OHGANE Takeo, OGAWA Yasutaka, NISHIMURA Toshihiko, Proceedings of the IEICE General Conference, 2005, 1, 533, 533, 07 Mar. 2005
一般社団法人電子情報通信学会, Japanese

A-5-5 Interference cancelation in UWB-IR Systems with a Filter Based on an MMSE Criterion
Takanashi Masaki, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2005, 121, 121, 07 Mar. 2005
一般社団法人電子情報通信学会, Japanese

Performance Comparison of MIMO-SDM Depending on Array Configurations Based on Indoor Measurements
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 104, 676, 123, 128, 24 Feb. 2005
A MIMO measurement campaign was conducted in indoor multipath-rich line-of-sight (LOS) and non-LOS (NLOS) environments. In this paper, for various antenna array configurations, we examined the performance of bit error rate (BER) for 2×2 and 4×4 MIMO-SDM systems using the actual channel state data with mutual coupling of antennas, and considered the effects of channel correlations and eigenvalue distributions. Results showed that MIMO channels in LOS generally give better BER performance than those in NLOS. Meanwhile, we also found that the performance in LOS tends to change largely depending on an array configuration., 一般社団法人電子情報通信学会, Japanese

Experimental Evaluation of a MIMO-OFDM System with MMSE-Ordered Successive Detection
MATSUNOSHITA Masahiro, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 679, 81, 86, 24 Feb. 2005
MIMO space division multiplexing in an OFDM system (MIMO-OFDM) can achive high-data-rate transmission without inter-symbol interference in frequency selective fading channels. In a receiver, however, spatial filtering must be needed to separate and detect transmitted signal, because received signals include transmitted signals from all the transmit antennas. We constructed an evaluation system with fading simulators in order to verify the MIMO-OFDM spatial division multiplexing system experimentaly. In this paper, we show some improvements of the hardware and processing software., 一般社団法人電子情報通信学会, Japanese

Interference Cancelation and Equalization in UWB-IR Systems with a Filter Based on an MMSE Criterion
TAKANASHI Masaki, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, 電子情報通信学会技術研究報告. A・P, アンテナ・伝播, 104, 675, 207, 212, 23 Feb. 2005
Japanese

A Study on Parallel Interference Canceller in a Coded MIMO-OFDM System
SHIBAHARA Koji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 678, 37, 42, 23 Feb. 2005
In this paper, it is considered to apply a parallel interference canceller (PIC) to a coded MIMO-OFDM system. In a hard canceller with a simple configuration, a cancelling factor is generally introduced to reduce the effect of error propagation due to low reliability replicas. Here, a novel hard canceller using a spatial filtering factor is proposed. In addition, a symbol-by-symbol PIC is also applied to reduce the packet processing delay. The simulation results show that it achieves low computational complexity and short packet processing delay, and that the performance degradation compared to soft PIC is reasonably small., 一般社団法人電子情報通信学会, Japanese

A Study on Computational Complexity Reduction of Iterative Decoding for Turbo-coded MIMO-SDM Using Sphere Decoding
SUMII Kenji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 678, 43, 48, 23 Feb. 2005
A turbo-coded MIMO-SDM system requires a soft-output MIMO detector. Although MAP-based soft-output detection is optimum, its hardware implementation is very difficult since its computational complexity increases exponentially with the antennas and constellations. Sphere decoding (SD) is one of promising ways to reduce the computational complexity effectively. In SD, however, it occasionally excludes signal points required for the likelihood estimation in turbo decoding. In this paper, we propose a method recovering the signal points outside the sphere, and its error performance is evaluated. The simulation results reveal its extremely low complexity., 一般社団法人電子情報通信学会, Japanese

A Study on MIMO for W-CDMA Uplink Channel
TANAKA Toyohisa, OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 599, 37, 42, 21 Jan. 2005
W-CDMA has already been operated as the 3rd generation mobile communication system. Continuously the 3rd Generation Partnership Project (3GPP) has been worked for enhancing the 3G systems. A specification of High Speed Downlink Packet Access (HSDPA), which enables up to 14.4Mbps data rate for downlink, was completed so far. In addition to the HSDPA, MIMO has been proposed to apply for further enhancement. We studied MIMO for W-CDMA uplink by using a computer simulation in this report., 一般社団法人電子情報通信学会, Japanese

B-1-241 Evaluation of 3×3 MIMO-SDM Using a Tripole Antenna Based on Indoor Propagation Measurment
Nishimura Toshihiko, Nishimoto Hiroshi, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 241, 241, 2005
一般社団法人電子情報通信学会, Japanese

B-5-23 An adaptive modulation control with eigenvalues in E-SDM
HATA Yasuo, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 423, 423, 2005
一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO-SDM Considering Mutual Coupling Based on Indoor Measurements
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 104, 396, 53, 58, 29 Oct. 2004
We measured MIMO channels with mutual coupling of antennas in indoor line-of-sight (LOS) and non-LOS (NLOS) environments where we have rich multipath signals. Using the measured data, we examined bit error rate performance, channel correlations, and eigenvalue distributions for 2x2 MIMO space division multiplexing (SDM) systems to evaluate effects of mutual coupling on the performance. We show that t,he MIMO-SDM is useful also in an indoor LOS environment, whereas the performance in the LOS environment tends to change significantly depending on an array configuration. Moreover, it is shown that the mutual coupling tends to effect on LOS channel data more largely than on NLOS ones., 一般社団法人電子情報通信学会, Japanese

Estimation of Channel and Frequency Offset in a MIMO-OFDM System
NAMKAMURA Yuichiro, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 104, 258, 79, 84, 20 Aug. 2004
An OFDM system has been used also for wireless local area networks. MIMO space division multiplexing in an OFDM system has been studied to achive high-speed transmission over lOOMbps. In this paper, we compare three methods of channel estimation using a few training symbols. We show that the time-domain minimum square error method that the authors have proposed enables accurate channel estimation. Furthermore, we develop this scheme to estimation of channel and frequency offset between a transmitter and a receiver. We show that the proposed method can estimate them using a preamble that have the same duration as that of the IEEE802.11 a standard., 一般社団法人電子情報通信学会, Japanese

Experimental Studies on a MIMO-OFDM System
MATSUNOSHITA Masahiro, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 258, 103, 107, 20 Aug. 2004
MIMO space division multiplexing in an OFDM system (MIMO-OFDM) can achive high-data-rate transmission without inter-symbol interference in frequency-selective fading channels. It has been reported that precise channel estimation is possible by using the training symbols with a low condition number even though the number of training symbols in an OFDM system (for example, IEEE802.ila) is small. In this paper, we evaluate sensitivity of channel estimation acculacy and BER performance to the condition number depending on the training symbols, experimentary, using a DSP-based MIMO-OFDM system., 一般社団法人電子情報通信学会, Japanese

Performance Analysis of MIMO-SDM Based on 5.2GHz Band Measurements in Indoor Environments
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, IEICE technical report. Antennas and propagation, 104, 202, 25, 30, 15 Jul. 2004
We measured MIMO channels in a line-of-sight (LOS) environment where channels may be correlated, then examined bit error rate performance for 2 × 2 MIMO-SDM and eigenvalue distributions to compare with channels, in a non-LOS (NLOS) environment. Furthermore, we analyzed channel data with mutual coupling between antennas, and evaluated its effect on the performance. We show that the performance of MIMO-SDM is useful also in a LOS environment where there are rich multipath signals, and that the performance in the LOS environment changes significantly depending on antenna spacing and array configuration. Moreover, it is shown that the presence of mutual coupling tends to effect on LOS channel data more largely than NLOS ones., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of a Parallel Interference Canceller for FEC-Coded MIMO-OFDM
SHIBAHARA Koji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 123, 31, 35, 11 Jun. 2004
MIMO space division multiplexing in an OFDM system can achieve very high-speed transmission. In this paper, a parallel interference canceller (PIC) is considered for coded MIMO-OFDM based on the IEEE standard 802.11a, and its performance is evaluated. In addition, we propose PIC processing symbol by symbol to reduce a processing delay. Numerical analysis shows that PIC has better PER performance compared to spatial filtering, and that severe degradation is not observed in the symbol PIC., 一般社団法人電子情報通信学会, Japanese

A Study on Computational Complexity Reduction for Turbo-coded MIMO-SDM
SUMII Kenji, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 104, 123, 37, 42, 11 Jun. 2004
A soft output MIMO decoder is required for turbo-coded MIMO-SDM. Although soft output maximum likelihood detection (MLD) is optimal, its computational complexity prevents application to iterative decoding of turbo decoding and soft output MIMO decoding. We propose a complexity reduction method for soft output MLD in iterative decoding, and also consider the application to partial search MLD. Computer simulation results show that the proposed method reduces complexity effectively., 一般社団法人電子情報通信学会, Japanese

B-5-32 Performance Evaluation of Parallel Interference Canceller for FEC-coded MIMO-SDM
Shibahara Koji, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2004, 1, 519, 519, 08 Mar. 2004
一般社団法人電子情報通信学会, Japanese

SB-1-2 Estimation of Frequency Offset and Channel in MIMO-OFDM Systems
Nishio Keisuke, Ogawa Yasutaka, Nishimura Toshihiko, Ohgane Takeo, Proceedings of the IEICE General Conference, 2004, 1, "S, 27"-"S-28", 08 Mar. 2004
一般社団法人電子情報通信学会, Japanese

SB-1-5 Effects on MIMO Space Division Multiplexing in Indoor LOS Environments
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Proceedings of the IEICE General Conference, 2004, 1, "S, 33"-"S-34", 08 Mar. 2004
一般社団法人電子情報通信学会, Japanese

Complexity reduction approaches for SDM systems in a frequency selective MIMO channel
FURUTA Takayuki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 103, 680, 49, 54, 25 Feb. 2004
In a frequency selective MIMO channel, a maximum likelihood receiver performing both joint detection and sequence estimation is optimum. However, an increase of the number of delayed waves and substreams complicates the receiver process exponentially. We applied sphere decoding (SD) and M-algorithm (MA) for complexity reduction to the receiver in convolutional-coded SDM and E-SDM systems. In this paper, we evaluate effects of those algorithms in both complexity reduction and performance degradation., 一般社団法人電子情報通信学会, Japanese

MIMOチャネルにおける空間分割多重方法とその基本特性
大鐘武雄, 信学論 (B), 87, 9, 1162, 1171, 2004

B-5-29 A Study on Itertive Decoding in Turbo-Coded MIMO-SDM
SUMII Kenji, NISHIMURA Toshihiko, OHGANE Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 516, 516, 2004
一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO Space Division Multiplexing in Actual Channels
NISHIMOTO Hiroshi, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 103, 460, 139, 144, 21 Nov. 2003
Independent and identically distributed (i. i. d.) Rayleigh channels between transmit and receive antennas have been assumed in many studies on MIMO space division multiplexing (MIMO-SDM). In this case, transmitted streams can be separated and detected by processing at a receiver end. However, channels may be correlated in a line-of-sight (LOS) environment. We measured MIMO channels in a very rich multipath environment, and showed that the performance of LOS channels is more excellent than that of NLOS (Non-LOS) ones. We also evaluated the performance of channels measured in an an-echoic chamber where we do not have rich multipath propagation., 一般社団法人電子情報通信学会, Japanese

Performance Evaluation of MIMO Space Division Multiplexing in Line-Of-Sight (LOS) Channels
NISHIMOTO Hiroshi, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2003, 1, 236, 236, 10 Sep. 2003
一般社団法人電子情報通信学会, Japanese

Studies on Direction of Arrival Estimation for Adaptive Antenna Control in DS-CDMA Systems
OHSHIMA Kohzoh, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2003, 1, 383, 383, 10 Sep. 2003
一般社団法人電子情報通信学会, Japanese

A study on OFDM-STTuC with feedback information
HOSHINO Masayuki, UESUGI Mitsuru, OHGANE Takeo, OGAWA Yasutaka, NISHIMURA Toshihiko, Proceedings of the Society Conference of IEICE, 2003, 1, 390, 390, 10 Sep. 2003
一般社団法人電子情報通信学会, Japanese

Performance of MIMO-SDM communications in Nakagami-Rician fading
Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Takatori Yasushi, Cho Keizo, Proceedings of the Society Conference of IEICE, 2003, 1, 408, 408, 10 Sep. 2003
一般社団法人電子情報通信学会, Japanese

Signal Processings in MIMO Sytems
Ohgane Takeo, Ogawa Yasutaka, Nishimura Toshihiko, Proceedings of the Society Conference of IEICE, 2003, 1, "SS, 34"-"SS-35", 10 Sep. 2003
一般社団法人電子情報通信学会, Japanese

Sphere decoding in a frequency selective MIMO channel
FURUTA Takayuki, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 103, 253, 7, 12, 21 Aug. 2003
In a frequency selective MIMO channel, the maximum likelihood receiver performing both joint detection and sequence estimation is optimum. However, an increase of the number of delayed waves and substreams complicates the receiver process, exponentially. In this paper, we apply Sphere Decoding (SD) to the receiver. SD limits the number of constellation points to be searched by setting a sphere around a received signal. Here, we evaluate effects of sequence estimation to SD and the performance., 一般社団法人電子情報通信学会, Japanese

An impact of channel state information error on SDM applications
TSUTSUMI Takahiko, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 103, 204, 13, 18, 18 Jul. 2003
For some SDM applications, performance degradation due to error in channel state information is numerically analyzed. In addition, a channel prediction method using first order extrapolation is proposed. The computer simulation results show that SDM using a joint detector outperforms E-SDM and w-SDM which requires channel state information at the transmitter in fast fading condition. However, by using the channel prediction, the performance of E-SDM and w-SDM is improved., 一般社団法人電子情報通信学会, Japanese

Studies on MIMO Space Division Multiplexing in an OFDM System
NISHIO Keisuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 103, 66, 83, 90, 23 May 2003
MIMO space division multiplexing in an OFDM system can achieve very high-speed transmission. This paper nresents signal separation techniques for spatially multiplexed signals. We consider a channel estimation scheme using a very few training symbols. Then, we investigate reasons for degradation of channel estimation accuracy, and propose training symbol selection for better channel estimation. Also, we examine several MIMO reception techniques., 一般社団法人電子情報通信学会, Japanese

A Study on E-SDM in a Frequency Selective Channel
Furuta Takayuki, Ohgane Takeo, Nishimura Toshihiko, Ogawa Yasutaka, Tomisato Shigeru, Proceedings of the IEICE General Conference, 2003, 1, 775, 775, 03 Mar. 2003
一般社団法人電子情報通信学会, Japanese

A study on weight compensation for time-variant channel in E-SDM
Tsutsumi Takahiko, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2003, 1, 776, 776, 03 Mar. 2003
一般社団法人電子情報通信学会, Japanese

Throughput performance of weighted BLAST transmission in a MIMO channel
Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Takatori Yasushi, Cho Keizo, Proceedings of the IEICE General Conference, 2003, 1, "S, 55"-"S-56", 03 Mar. 2003
一般社団法人電子情報通信学会, Japanese

On performance of FEC in E-SDM
KIMURA Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 102, 675, 1, 5, 27 Feb. 2003
In multiple-input multiple-output channels, channel capacity is highly improved by eigenbeam space division multiplexing (E-SDM), when the channel response is known at a transmitter. In this paper, we introduce FEC (turbo codes, in specific) to the E-SDM and evaluate its performance. Computer simulations show the results on performance improvement due to coding gain. However, the improvement is larger in the SDM case. Thus, the performance of E-SDM and SDM becomes very close., 一般社団法人電子情報通信学会, Japanese

Fundamental Studies on MIMO-OFDM Space Division Multiplexing
NISHIO Keisuke, OGAWA Yasutaka, NISHIMURA Toshihiko, OHGANE Takeo, Technical report of IEICE. RCS, 102, 551, 121, 126, 10 Jan. 2003
OFDM is useful for high-speed transmission in a multipath environment. Space division multiplexing in a MIMO system can increase a transmission rate because different transmit antennas radiate indivisual signals. This paper describes an adaptive antenna configuration and weight control method for the OFDM system. Then, the authors propose MIMO-OFDM space division multiplexing based on the adaptive antenna. It is shown from computer simulations that the proposed system reveals excellent performance., 一般社団法人電子情報通信学会, Japanese

Evaluation of weighted BLAST compared with E-SDM in MIMO Channel Systems
NISHIMURA T, OHGANE T, OGAWA Y, TAKATORI Y, CHO K, Technical report of IEICE. RCS, 102, 551, 127, 132, 10 Jan. 2003
In this paper, two schemes to improve channel capacity, weighted-BLAST and E-SDMA, are evaluated in multiple-input multiple-output (MIMO) channels, when the channel response matrix is known at a transmitter. In the paper, we describe transmitting power and bit rate controls for each scheme, and three receiving methods for weighted-BLAST is examined by numerical simulations. Also, bit error rates of weighted-BLAST and E-SDM are computed and compared. The results show that the weighted BLAST is a promising scheme for some applications because of less feedback data and less terminal load even though bit error rate is higher than E-SDM., 一般社団法人電子情報通信学会, Japanese

Result of The Laboratory Test for SDMA Downlink Performance Improved by Estimating The Downlink Channel Response
Doi Yoshiharu, Ito Tadayoshi, Iwami Masashi, Nakao Seigo, Miyata Takeo, Kitakado Jun, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, "S, 43"-"S-44", 2003
一般社団法人電子情報通信学会, Japanese

Studies on Direction of Arrival Estimation for Downlink Adaptive Antennas in the W-CDMA system
OHSHIMA Kohzoh, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report, 102, 201, 31, 36, 17 Jul. 2002
Adaptive Antennas have been proposed to reduce interference in the W-CDMA system. These antennas for downlink transmission need to estimate direction of arrivals (DOAs) using uplink signals to determine the weights. We avoid using a super-resolution method such as MUSIC and ESPRIT to reduce the computational load. We estimate the DOAs calculating the phase difference between two adjacent antenna elements. This paper presents computer simulation results of this DOA estimation method., 一般社団法人電子情報通信学会, Japanese

Studies on 2-Dimensional DOA Estimation Using a Cylindrical Array
TAKANASHI Masaki, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 102, 230, 77, 82, 17 Jul. 2002
A uniform linear array (ULA) has been mainly used for DOA estimation of coherent signals because we can apply the spatial smoothing preprocessing (SSP) technique. However, the ULA has ambiguity due to the symmetry, and the estimation accuracy depends on the DOA. Although these problems can be solved by using a uniform circular array (UCA), we cannot estimate the DOA of coherent signals because the SSP technique cannot be employed for the UCA. In this paper, we propose to estimate 2-dimensional DOA (polar angle and azimuth angle) of the coherent signals using a cylindrical array which is composed of stucked UCAs., 一般社団法人電子情報通信学会, Japanese

A Study on SDM Turbo Codes in a MIMO Channel
KIMURA Hiroshi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 102, 204, 19, 24, 10 Jul. 2002
The performance of Turbo Codes in MIMO systems was evaluated. When the channel state information is not known at a transmitter, the BER performance of Turbo codes using space division multiplexing (SDM) was numerically analyzed in comparison to Turbo codes with space-time block codes (STBC). When the channel state information is known at a transmitter in a MIMO system, we evaluated the BER performance combining Turbo Codes and E-SDM/transmit MRC. The simulation results for an unknown channel assuming 4-tx and 2-rx antennas show that Turbo codes using SDM have better BER performance than Turbo codes with STBC. For a known channel, the performance of Turbo codes with MRC is better., 一般社団法人電子情報通信学会, Japanese

Evaluation of E-SDM Performance in the Presence of Channel Estimation Error
NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, TAKATORI Yasushi, CHO Keizo, Technical report of IEICE. RCS, 102, 204, 25, 30, 10 Jul. 2002
Eignebeam-space division multiplexing (E-SDM) in the MIMO channel is effective when a receiver has less number of elements. In this paper, we evaluate E-SDM performance in the presence of chanel estimation error between channel response matrices used for determining transmit weights and actual channel responce ones. Average BER performance for maximal ratio combining has error floor because eigenbeams are not formed perefectly orthogonal. Therfore, zero-forcing method or joint detection are needed. The results of computer simulation show that the E-SDM method is superiour to normal SDM while channel correlation is over 0.8 with the joint detector., 一般社団法人電子情報通信学会, Japanese

Eigenbeam-Space Division Multiplexing (E-SDM) in a MIMO Channel
MIYASHITA Kazumi, NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, TAKATORI Yasushi, CHO Keizo, Technical report of IEICE. RCS, 102, 86, 13, 18, 17 May 2002
In MIMO systems, when the channel state information is known at transmitter, the optimum capacity is given by eigenmode channel division with the water filling power control. In this paper, eigenbeam-space division multiplexing (E-SDM) is proposed based on that concept, and the BER performance is numerically analyzed in comparison to the conventional SDM. The simulation results assuming 5-tx and 2-rx antennas show that the E-SDM provides about 10 dB gain compared to the conventional SDM at average BER of 10^-3., 一般社団法人電子情報通信学会, Japanese

Performance of A Four Antenna Elements Multibeam SDMA Base Station at Three Space Multiplex
DOI Yoshiharu, ITO Tadayoshi, KITAKADO Jun, MIYATA Takeo, NAKAO Seigo, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 102, 22, 171, 176, 12 Apr. 2002
Space division multiple access (SDMA) is a multiple access schemes for mobile communications that multiple users share the same frequency simultaneously, in the same area. The SDMA also supports any protocols, if a base station (BS) can steer multibeam. As a result, it allows several times more users to be accommodated compared to existing systems. We developed the SDMA BS for the Personal Handy phone Systems (PHS). We carried out several tests to evaluate the BS when three PSs access the BS by the SDMA. The results of indoor measurement showed that the BS has sufficient intereference suppression performance. Also, the antenna pattern measured in anechoic chamber showed that the BS can steer the multibeam correctly. Moreover, the results of field test showed that the traffic capacity was 2.4 times greater than the existing systems. Therefore, it was confirmed that the SDMA-PHS BS achieves substantial improvement in spectrum efficiency., 一般社団法人電子情報通信学会, Japanese

Downlink Nullforming by a Receiving Antenna Selection for a MIMO/SDMA channel
NISHIMURA Toshihiko, TAKATORI Yasushi, OHGANE Takeo, OGAWA Yasutaka, CHO Keizo, IEICE technical report, 101, 686, 17, 22, 07 Mar. 2002
In this paper, we propose a novel downlink nullforming technique for space division multiple access (SDMA) in a multi-input multi-output (MIMO) channel where a basestation and all terminal stations have multiple antennas. In the SDMA system, simple beamforming is not efficient to achieve a good performance due to cochannel interference (CCI). Proposed method is based on nullforming and characterized by an antenna element selection at each terminal where the selected antenna pair satisfies the lowest spatial correlation condition in all combinations. The results obtained by the computer simulations show the selective diversity gain of the proposed method and its performance improvement due to joint detection at each terminal., 一般社団法人電子情報通信学会, Japanese

Studies on Tap Coefficients for a Cascaded Connect Space-Time Equalizer
TANABE Yasuhiko, OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka, ASAI Takahiro, TOMISATO Shigeru, IEICE technical report, 101, 686, 23, 30, 07 Mar. 2002
In this paper, we discuss a cascaded connection of an adaptive array antenna, in which each antenna contains a feedforward filter, and the Viterbi equalizer. When using the feedforward filter, MMSE tap coefficients degrade the system performance because noise correlation in an array output becomes high. computer simulations show that proposed methods have better BER performance under a large delay spread condition and when the feedforward filters have few taps. In addition, we propose a method applying a multi-input Viterbi algorithm with a multi-beam adaptive array antenna. As a result, the proposed method improves BER performance significantly., 一般社団法人電子情報通信学会, Japanese

A Study on Channel Efficiency for SDMA with an Adaptive Array
SUZUKI Tohru, OHGANE Takeo, OGAWA Yasutaka, IEICE transactions on communications, 85, 3, 702, 702, 01 Mar. 2002
Recently, space division multiple access (SDMA) has been proposed to improve channel efficiency. In this paper, assuming an MMSE adaptive array at a base station, we examine the performance of the system with and without SDMA for both fixed channel assignment (FCA) and dynamic channel assignment (DCA). The performance is evaluated using incomplete service rate as quality of service in addition to the blocking rate and forced call termination rate. The results show that the SDMA achieves 2.08-fold and 1.2-fold capacity improvement at the blocking rate of 3% in FCA on 9 cells per cluster and in DCA, respectively., The Institute of Electronics, Information and Communication Engineers, English

MIMOチャネルにおける送信ダイバーシチの検討
宮下和巳, 大鐘武雄, 小川恭孝, 鷹取泰司, 長敬三, 電子情報通信学会大会講演論文集, 2002, 2002

受信アンテナ選択を用いたMIMO/SDMA下り回線送信ウエイト導出法
西村寿彦, 鷹取泰司, 大鐘武雄, 小川恭孝, 長敬三, 電子情報通信学会大会講演論文集, 2002, 2002

A SDMA/TDD-PHS Base Station based on a Multibeam Adaptive Array
DOI Yoshiharu, ITO Tadayoshi, KITAKADO Jun, MIYATA Takeo, NAKAO Seigo, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report. Antennas and propagation, 101, 489, 9, 14, 13 Dec. 2001
SDMA(Space Diveision Multiple Access) is one of the nultiple access schemes for mobile communications that multiple users share the same frequency simultaneously, in the same area. The SDMA also supports any protocols, if a base station can steer multibeam. As a result, it allows several times more users to be accommodated compared to existing systems. We have developed the SDMA-PHS(Personal Handy phone System) base station. Moreover, we carried out several tests to evaluate the system. The results of indoor measurement showed that the SDMA BS has enough interference suppression performance. Also, the results of field test showed that the traffic capacity was several times greater than the existing systems, and interference emitted from the base station was decreased. Therefore, it was confirmed that the SDMA-PHS base station achieves substantial improvement in spectrum efficiency., 一般社団法人電子情報通信学会, Japanese

A Study on Weight Control Methods of an Adaptive Antenna for Downlink Transmission in a W-CDMA System
MIYANO Taiki, OGAWA Yasutaka, KITAHARA Minako, OHGANE Takeo, MIYATANI Tetsuhiko, Technical report of IEICE. RCS, 101, 436, 19, 24, 12 Nov. 2001
Downlink capacity in a W-CDMA system is limitted by interference due to multipath propagation. Particularly, high-bit rate users with large transmit power cause serious multiple access interference (MAI) to other users. The large MAI can be reduced by using a base station adaptive array antenna. In this paper, we propose weight control methods based on direction-of-arrival estimation. These methods can be employed also in an asymmetric channels between uplink and downlink transmission. We compare the performance of the methods by computer simulations., 一般社団法人電子情報通信学会, Japanese

A Study on an Adaptive Array for an OFDM Communication System
IMAI Tomohiro, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 101, 368, 15, 21, 20 Oct. 2001
This paper proposes a new adaptive array that suppresses interference in an OFDM communication system. The adaptive array multiplies weights and input signals after FFT processing. The array can suppress all the multipath components of the interference within a guard interval using only one degree of freedom of array, and can exploit multipath components of the desired signal. We detect the multipaths of the desired and interference signals, and estimate complex amplitudes of them using an MMSE criterion. We obtain array response vectors for subcarriers using the FFT processing, and calculate the weights. Computer simulation results show that the output SINR and the BER performance of the proposed adaptive array are better than those of the conventional array., 一般社団法人電子情報通信学会, Japanese

Study on a Path-Selection Method for Adaptive Array Antenna in W-CDMA Downlink
KITAHARA Minako, MIYATANI Tetsuhiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 101, 368, 31, 38, 20 Oct. 2001
Multi-rate services are flexibly available by a W-CDMA system. High-bit rate signals with short spreading factor, cause large multiple access interference(MAI). There will be many high-bit rate users in downlink. Base station adaptive array antennas have been studied to suppress the large MAI. We have proposed a new adative array antenna weight control method. This method is effective for downlink, however user capacity and transmitting power vary depending on transmitting path. In this paper, we propose a path-selection method, which selects the most preferable path comparing with direction of arrival(DOA) and power level of each path., 一般社団法人電子情報通信学会, Japanese

SDMA Downlink Beamforming for a MIMO channel
NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 101, 371, 23, 30, 13 Oct. 2001
SDMA 方式の下り回線ビーム形成において, MISO(Multi-Input-Single-Output)およびMIMO(Multi-Input Multi-Output)チャンネルを想定した場合に, 結合推定機能をもつ端末での受信特性について考察する.希望信号の電力がそれぞれの端末で最大となる送信最大比合成ダイバーシチと, 干渉信号電力を最小とするヌル制御の概念から導出した下り回線でのビーム形成法について評価する.計算機シミュレーションから, 結合推定機能を持つ端末を用いた場合, ヌル制御によるビーム形成法は送信最大比合成ダイバーシチとなるビーム形成法より特性が優れているという結果が得られた., 一般社団法人電子情報通信学会, Japanese

The Antenna Pattern Measurement for The SDMA/TDD Base Station based on An Adaptive Array
Miyata Takeo, Doi Yoshiharu, Ito Tadayoshi, Iinuma Toshinori, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2001, 1, 371, 371, 29 Aug. 2001
一般社団法人電子情報通信学会, Japanese

Interference Measurement from The SDMA/TDD Base Station based on An Adaptive Array in The Field
Shimada Minoru, Kitakado Jun, Doi Yoshiharu, Ito Tadayoshi, Iinuma Toshinori, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2001, 1, 373, 373, 29 Aug. 2001
一般社団法人電子情報通信学会, Japanese

Performance of The SDMA Base Station Employing Multistage Interference Canceller and Adaptive Array
Nakao Seigo, Kitakado Jun, Doi Yoshiharu, Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 2001, 1, 374, 374, 29 Aug. 2001
一般社団法人電子情報通信学会, Japanese

Applications of the MUSIC Algotithm and Genetic Algorithm to Distributed Sources
OHSHIMA Kohzoh, TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 2001, 1, 539, 540, 29 Aug. 2001
一般社団法人電子情報通信学会, Japanese

Estimation of Distributed Sources Using the MUSIC Algorithm and Genetic Algorithm
OHSHIMA Kohzoh, TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 101, 231, 25, 30, 27 Jul. 2001
In mobile communications, a mobile terminal is usually not in a line-of-sight condition from a base station. In this case, signals are assumed to be incident on the base station having angular spread by many scattering objects surrounding the mobile terminal. It is important to estimate these distibuted sources. We can estimate directions-of-arrival using the MUSIC or ESPRIT algorithm. However, it is difficult to apply the method to distributed sources. In this paper, we propose a scheme to estimate distributed sources using the MUSIC algorithm and genetic algorithm., 一般社団法人電子情報通信学会, Japanese

A Study on Subcarrier Transmitting Power Assignment for OFDM
ZUKAWA Hiroki, OHGANE Takeo, OGAWA Yasutaka, IEICE technical report, 101, 195, 55, 60, 19 Jul. 2001
Orthogonal frequency division multiplexing (OFDM) is regarded as one of candidates for the high-speed digital mobile communications. When applying an OFDM system in a multipath environment, each subcarrier suffers from different attenuation by frequency selective fading. Therefore, a methods assigning different transmitting power for each subcarrier according to the propagation quality has been investigated. In this study, the performance of a transmitting power assignment using instantaneous information of a channel state is evaluated., 一般社団法人電子情報通信学会, Japanese

Downlink weight control using channel response estimation in TDD/SDMA
MIYASHITA Kazumi, OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka, DOI Yoshiharu, Technical report of IEICE. RCS, 101, 197, 31, 36, 12 Jul. 2001
Recently, with the demand on capacity increase, space division multiple access(SDMA) has been studied in order to improve channel efficiency. In TDD/SDMA using an adaptive array for a base station, weight control using a channel response estimated by first-order extrapolation is known as improving the BER performance in downlink. However, the performance degrades with increase of the fading speed. In this paper, we propose a channel response estimation method using exponential function approximation and evaluate its performance., 一般社団法人電子情報通信学会, Japanese

A study on a criterion of channel assignment for SDMA using an instantaneous spatial correlation
WAKABAYASHI Daisuke, SUZUKI Tohru, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 100, 663, 43, 49, 08 Mar. 2001
In this paper, we propose to employ a spatial correlation coefficient as a criterion of channel assignment for SDMA in an angle-spread multipath channel. In the angle-spread multipath channel, an average spatial correlation coefficient becomes the criterion to determine the duplicate channel assignment. However, it is impossible to measure an average spatial correlation once at the request of channel assignment. Here, we propose to use the instantaneous spatial correlation coefficient as a criterion. The performance is evaluated using incomplete call ratio (ICR) as quality of service (QoS) and handover request ratio (HRR). The results show low HRR of the proposed methods., 一般社団法人電子情報通信学会, Japanese

A Downlink Multiplexing Method in TDD Packet Radio Networks with a Multibeam Adaptive Array
HIGASHINAKA Masatsugu, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 100, 663, 87, 93, 08 Mar. 2001
In previous studies, a PRMA permitting multiple reservation with a multibeam adaptive array has been investigated considering uplink performance only. This paper proposes a downlink multiplexing method for TDD packet radio networks with the multibeam adaptive array. When we select transmission terminals, the method limits to terminals with long packet delay to decrease processing load. The transmission weight is calculated using the array response vector obtained in uplink, and SINR of each terminal is estimated to decide multiplexing possibility. The computer simulation results show the improvement in throughput and average packet delay without increasing processing load., 一般社団法人電子情報通信学会, Japanese

A Study on Transmit Diversity Techniques Using Turbo-Codes
YAMASHITA Morifumi, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 100, 663, 121, 126, 08 Mar. 2001
In this paper we present transmit diversity techniques using turbo-codes to improve receiver performance in a fading channel. In our previous study, we proposed the transmit diversity scheme implementing space division multiplexing (SDM) with turbo-coding for a BPSK signal. Here, we consider an enhancement of the proposed scheme to the multilevel modulation. The computer simulation results assuming a QPSK signal show that the proposed scheme has a better performance compared to other combing schemes., 一般社団法人電子情報通信学会, Japanese

Spatial Domain Multistage Interference Canceller with Error Correction
Nishimura Toshihiko, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 2001, 1, 400, 400, 07 Mar. 2001
一般社団法人電子情報通信学会, Japanese

Applications of the MUSIC Algorithm to Distributed Sources
OHSHIMA Kohzoh, TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the IEICE General Conference, 58, 58, 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

Adaptive Array Antennas for Downlink Transmission in a W-CDMA System
KITAHARA Minako, MIYATANI Tetsuhiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the IEICE General Conference, 413, 413, 2001
一般社団法人電子情報通信学会, Japanese

Optimal Subcarrier Power Allocation for a Multi-carrier System
ZUKAWA Hiroki, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 480, 480, 2001
一般社団法人電子情報通信学会, Japanese

Performance of The Adaptive Array PHS Base Station
Ito Tadayoshi, Doi Yoshiharu, Iinuma Toshinori, Ohgane Takeo, Ogawa Yasutaka, Nomachi Masanori, Proceedings of the Society Conference of IEICE, 369, 369, 2001
一般社団法人電子情報通信学会, Japanese

Development of The SDMA/TDD Software Radio Base Station based on An Adaptive Array
Doi Yoshiharu, Ito Tadayoshi, Iinuma Toshinori, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 370, 370, 2001
一般社団法人電子情報通信学会, Japanese

Performance of the SDMA/TDD Base Station based on An Adaptive Array in The Field
Kitakado Jun, Doi Yoshiharu, Ito Tadayoshi, Iinuma Toshinori, Ohgane Takeo, Ogawa Yasutaka, Shimada Minoru, Proceedings of the Society Conference of IEICE, 372, 372, 2001
一般社団法人電子情報通信学会, Japanese

A Study on a High-Resolution Time Delay Estimation in the Presence of a Carrier Frequency Offset
TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 100, 341, 37, 42, 14 Oct. 2000
In a future mobile communication system, it will be required to realize much higher transmission services than the present ones. Time delay estimation is one of the important techniques in frequency-selective fading environments. We have proposed a method, called TD-MUSIC, to estimate the time delays by analyzing received composite modulation signal in a time domain. However, we have assumed that carrier frequency has been recovered exactly. In this paper, we examine the performance of TD-MUSIC algorithm in the presence of carrier frequency offset. The computer simulations show that the performance is not degraded so much by the frequency offset., 一般社団法人電子情報通信学会, Japanese

Studies on a Reference Signal Synchronization Scheme for MMSE Adaptive Antennas
YONEZAWA N, OGAWA Y, NISHIMURA T, OHGANE T, DOI Y, Technical report of IEICE. RCS, 100, 347, 29, 35, 07 Oct. 2000
Timing synchronization of a reference signal with an incident desired signal is required to control an adaptive antenna based on the MMSE criterion. This paper proposes to use nsrrow-band filters whose bandwidth is narrower than that of the root Nyquist filter. In the first weight control, the adaptive antenna weights are determined almost properly, since the narrow-band filter increases the correlation between the incident desired signal and the reference signal with timing error. The second synchronization of the reference signal at the array output is accurate, and the adaptive antenna can determine the weights more precisely. The computer simulation results show the improvement of the synchronization accuracy, SINR, and the BER performance., 一般社団法人電子情報通信学会, Japanese

Considerations on High Resolution Time-Domain Estimation by the Beamspace MUSIC Algorithm under Multiple Incident Signal Environment
KIMURA Masatoshi, TANABE Yasuhiko, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, IEICE technical report. Antennas and propagation, 100, 218, 23, 28, 27 Jul. 2000
Time-domain measurements are widely spread, which estimate time delays of signals applying the inverse Fourier transform to frequency-domain data measured by a networkanalyzer. We can use the MUSIC algorithm for separating closely located signals. However, the performance of the MUSIC algorithm deteriorates under multiple signal environment. In this paper, we propose the beamspace MUSIC algorithm for the above environment. We also compare the results of the beamspace MUSIC with those of the gating technique. The beamspace MUSIC tends to show better performance than the gating technique., 一般社団法人電子情報通信学会, Japanese

A Study on PRMA with a Multibeam Adaptive Array for Integrated Voice and Data
HIGASHINAKA Masatsugu, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. SSE, 100, 193, 69, 74, 19 Jul. 2000
PRMA permitting multiple reservation with a multibeam adaptive array has been proposed for a wireless voice network. This paper analyzes PRMA with the multibeam adaptive array for an integrated voice and data network, and proposes a new reservation method using different permission probability for an unreserved slot and a partially reserved slot. Terminals transmit a packet with high permission probability for the unreserved slot, and transmit it with low permission probability for the partially reserved slot. The computer simulation results show the improvement in voice packet dropping probability and average data packet delay., 一般社団法人電子情報通信学会, Japanese

A Study on Transmit Diversity Techniques Using Turbo-Codes
YAMASHITA Morifumi, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. SSE, 100, 192, 83, 88, 18 Jul. 2000
In this paper we study transmit diversity techniques using turbo-codes to improve receiver performance in a fading channel and evaluate BER of some combining schemes by computer simulations. Furthermore, we propose a new scheme implementing space division multiplexing with turbo-coding. It is characterized by the method multiplexing data and parity in turbo-encoding and turbo-decoding without separating signals. Simulation results show that the proposed scheme has a better performance compared to other combing schemes., 一般社団法人電子情報通信学会, Japanese

High-Resolution Time Delay Estimation of Multipath Signals Using the Genetic Algorithm
Araki Hiroshi, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 2000, 1, 41, 41, 07 Mar. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

Performance of spatial domain-multistage interference canceller with timing estimation
NISHIMURA T, CHIBA T, TANABE Y, OHGANE T, OGAWA Y, KITAKADO J, DOI Y, Proceedings of the IEICE General Conference, 2000, 1, 412, 412, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

A Study on Time Delay Estimation in Multipath Propagation Environment
TANABE Yasuhiko, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the IEICE General Conference, 2000, 1, 492, 492, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

A Criterion of Channel Assignment for SDMA in an Angle-spread Multipath Channel
WAKABAYASHI Daisuke, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 2000, 1, 524, 524, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

A beam-space projected array procesing MLSE
HANAKI Akihito, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 2000, 1, 527, 527, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

An Adaptive Array Antenna for Downlink Transmission under Many User Environment in a DS-CDMA System
KITAHARA Minako, OGAWA Yasutaka, OHGANE Takeo, RCS, 99, 638, 1, 8, 18 Feb. 2000
Multi-rate Services are flexibly available by a DS-CDMA technique.Since high-bit rate signals have high transmitted power, they cause large multiple access interference(MAI)to low-bit rate users.A base station adaptive antenna has been studied tosuppress the large MAI from the high-speed users.In an uplink case, the adaptive antenna for a low-speed user needs to reduce received power of the high-speed signals.This is carried out by forming nulls toward the high-bit rate users.In the downlink case, however, the adaptive antenna for the high-bit rate user needs to reduce transmitted power toward the low-bit rate users.The conventional adaptive antenna suppresses high-bit rate signals strongly.That is, the interference to the low-bit rate users cannot be rejected.in this paper, we propose a novel adaptive array structure to reduce the high-bit rate interference., 一般社団法人電子情報通信学会, Japanese

A Studies on a Spatial-Domain Path-Diversity System with a Multibeam Adaptive Antenna
TANABE Y, FUJISHIMA K, NISHIMURA T, OGAWA Y, OHGANE T, Technical report of IEICE. RCS, 99, 638, 15, 20, 18 Feb. 2000
In a high speed TDMA system, frequency-selective fading is a serious problem.A spatial-domain path-diversity system using multibeam adaptive antenna has been proposed to reduce the frequency-selective fading, and to realize diversity.In this system, we need to estimate the time delays of multipath signals.If the estimation is not accurate, the system performance degrades.For this reason, the MUSIC algorithm has been proposed for the time delays estimation.However, the MUSIC algorithm needs a large quantity of operations.In this paper, we propose to use another scheme which is called an orthogonal vectors method.It needs much less operations, but the BER performance is almost the same as that of the MUSIC algorithm., 一般社団法人電子情報通信学会, Japanese

アダプティブアレーを用いたSDMA方式におけるチャネル利用効率の検討 (移動通信ワークショップ)
鈴木 達, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告, 99, 638, 9, 14, 18 Feb. 2000
電子情報通信学会, Japanese

アレーアンテナとMLSEを用いた時空間等化処理に関する考察 (移動通信ワークショップ)
花木 明人, 大鐘 武雄, 小川 恭孝, 電子情報通信学会技術研究報告, 99, 638, 21, 26, 18 Feb. 2000
電子情報通信学会, Japanese

SDMA方式における上り回線特性の改善に関する検討
岸山 祥久, 大鐘 武雄, 西村 寿彦, 電子情報通信学会技術研究報告, 99, 565, 17, 24, 21 Jan. 2000
電子情報通信学会, Japanese

Performance of PRMA with a Multibeam Adaptive Array in a Multicell Environment
HIGASHINAKA Masatsugu, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 533, 533, 2000
一般社団法人電子情報通信学会, Japanese

Transmit Diversity Using SDM and Turbo-codes
YAMASHITA Morifumi, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 289, 289, 2000
一般社団法人電子情報通信学会, Japanese

Space Domain-Multistage Interference Canceler for SDMA
NISHIMURA Toshihiko, DOI Yoshiharu, OHGANE Takeo, OGAWA Yasutaka, KITAKADO Jun, Technical report of IEICE. RCS, 99, 357, 103, 108, 15 Oct. 1999
It is a serious problem that interference is not efficiently canceled when the interference signals arrive from close directions to that of desired signal in an SDMA system, in which an adaptive array is used as the interference canceler. In this paper, we propose space domain-multistage interference canceler for the SDMA as a method to overcome the problem. The performance of this method is evaluated by computer simulations considering the PHS reverse link environment. The results show the remarkable improvement in high spatial-correlation situations., 一般社団法人電子情報通信学会, Japanese

Considerations on a Spatial-Domain Path-Diversity System Using the MUSIC Algorithm
TANABE Yasuhiko, FUJISHIMA Kenzaburoh, NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 99, 356, 89, 95, 14 Oct. 1999
In high speed TDMA mobile communications, frequency-selective fading is a serious problem because a delay difference between multipath signals is large in comparison with symbol duration. We have proposed spatial-domain path-diversity using a multibeam adaptive antenna. In the spatial-domain path-diversity system, the multibeam adaptive antenna resolves multipath signals in the spatial domain, and the system combines array outputs aligning the delay time. In this paper, we propose the application of MUSIC algorithm to estimate the delay time. Because estimation of the delay time using the MUSIC algorithm is precise, the BER (Bit Error Rate) performance of the proposed scheme is improved. Furthermore, we propose weighting factors which easily realize the maximal ratio combining., 一般社団法人電子情報通信学会, Japanese

DS-CDMAシステムの下り回線用アダプティブアレーアンテナ
北原 美奈子, 小川 恭孝, 大鐘 武雄, 電子情報通信学会技術研究報告, 99, 356, 81, 88, 14 Oct. 1999
電子情報通信学会, Japanese

Fundamental Studies on Spatial Domain Path Diversity Using Super-Resolution Delay Estimation
TANABE Yasuhiko, FUJISHIMA Kenzaburou, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 1999, 1, 275, 275, 16 Aug. 1999
一般社団法人電子情報通信学会, Japanese

A Study on Simplification for Delay Estimation of Multipath Signals
NISHIMURA Toshihiko, TANABE Yasuhiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1999, 1, 314, 314, 16 Aug. 1999
一般社団法人電子情報通信学会, Japanese

A Proposal of an Adaptive Array Anntenna for Downlink Transmission in a DS-CDMA system
KITAHARA Minako, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 1999, 1, 399, 400, 16 Aug. 1999
一般社団法人電子情報通信学会, Japanese

A Study on reference signal synchronization for PHS/SDMA system
NISHIMURA Toshihiko, TANABE Yasuhiko, OHGANE Takeo, OGAWA Yasutaka, DOI Yoshiharu, Technical report of IEICE. RCS, 99, 141, 61, 66, 24 Jun. 1999
Since the preamble in PHS is common for all users, it can not be used for training the adaptive array weight as it is. Considering the PHS/SDMA system, only one solution is to provide the transmission timing difference between the users accommodated in the same channel. Then, the timing detection is required. For the first user, it is easy to estimate it since there is no interference. However, the timing of the second user must be estimated in rich interfered situation. In this paper, with some estimation methods the estimation performance is evaluated., 一般社団法人電子情報通信学会, Japanese

Weight estimation for down-link null forming in TDD/SDMA system
KISHIYAMA Yoshihisa, OHGANE Takeo, NISHIMURA Toshihiko, OGAWA Yasutaka, DOI Yoshiharu, Technical report of IEICE. RCS, 99, 141, 67, 72, 24 Jun. 1999
In TDD/SDMA employing an adaptive array at a base station, generally, the array pattern for down-link is calculated from that for up-link. Considering the angle spread in the Rayleigh fading channel, time difference between up and down-link causes null position changes on the optimum array pattern. In this paper, we propose the weight estimation method for the down-link null forming. It is based on that the weight is uniquely determined by the array response vector. Here, we discuss the array response estimation and the performance of the down-link null forming., 一般社団法人電子情報通信学会, Japanese

Studies on Optimum Combining in Spatial-Domain Path-Diversity Using an Adaptive Array
FUJISHIMA Kenzaburoh, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 99, 19, 19, 24, 22 Apr. 1999
In high-speed digital mobile communications, frequency-selective fading due to multipath propagation causes serious performance degradation. In order to reduce distortion and to untilize transmitted signal power efficiently, we have proposed spatial-domain path-diversiy using an adaptive array with several sets of complex weight vectors. When maximal ratio combining is realized, bit error rate (BER) performance becomes optimum because the SINR becomes maximum. Unfortunately, it can not be realized strictly. In this paper, approximate maximal ratio combining is proposed. Simulation results show that the BER performance is very close to that of the strict maximal ratio combining and that the proposed method provides much better BER performance compared with that of equal gain combining. Furthermore, we propose a method to select a part of multipath signals. The method is to choose signals with higher approximate SINR. Simulation Results show that the selection method reveals excellent BER performance., 一般社団法人電子情報通信学会, Japanese

B-5-48 Effects of timing jitters to PHS signals in SDMA using an adaptive array
NISHIMURA Toshihiko, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 1999, 1, 399, 399, 08 Mar. 1999
一般社団法人電子情報通信学会, Japanese

B-5-49 A Study on ARP/SDMA in Sectored Cellular System
SUZUKI Tohru, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 1999, 1, 400, 400, 08 Mar. 1999
一般社団法人電子情報通信学会, Japanese

A study on PRMA radio network permitting multiple reservation by using a multibeam adaptive array
ITO Kuniaki, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 98, 601, 117, 122, 18 Feb. 1999
One of the problem in the packet radio network is throughput degradation due to packet from the collision packets, simultaneously.In this paper, the multiple reservation technique in PRMA radio networks is proposed by applying the MBAA to the central station.Here, it should be noted that the additional reservation might cause the cancellation of the original one. The computer simulations show that both high throughput and low dropping probability are obtained by giving the priority to originally reserved terminals. The achieved maximum capacity with 2-element MBAA can be improved about twice as much as the one of ordinary PRMA., 一般社団法人電子情報通信学会, Japanese

B-1-59 An Analysis of Multipath Propagation with a 2-D MUSIC Algorithm using Time-Domain Data
TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the IEICE General Conference, 59, 59, 1999
一般社団法人電子情報通信学会, Japanese

A Criterion of Channel Allocation for 3-user SDMA with and Adaptive Array
TANAKA Daisuke, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 98, 358, 103, 108, 22 Oct. 1998
Recently, a space division multiple access(SDMA)concept has been proposed to improve channel efficiency. This paper describes 3-user SDMA using an adaptive array. A spatial correlation cofficient can be defined as a criterion to determine the possibility of triplicate channel allocation. When 3 users are in a cell, 3 pairs for the spatial correlation cofficient are defined. The criterion proposed previously is to examine the maximum value of those since it is expected to represent the worst case. However, we found that the lower correlation pair might have worse performance. Therefore, the novel criterion using the squared sum of each coefficient and correlation coefficient product is presented., 一般社団法人電子情報通信学会, Japanese

High-Resolution Analysis of Multipath Propagation Using Time-Domain Signals
TANABE Yasuhiko, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 98, 358, 109, 114, 22 Oct. 1998
In digital radio communication systems, multipath signals hinder high speed transmission. In this paper, we propose a new MUSIC algorithm using time-domain data. This algorithm makes use of difference of DOA(Direction Of Arrival)to decorrelate signal correlation. We show that the algorithm realizes high-resolution estimation, and that it improves the resolution performance with a PN correlation method. Also, we propose a 2-dimentional MUSIC algorithm that estimates delay time and DOA. We show that the algorighm reveals high-resolution performance., 一般社団法人電子情報通信学会, Japanese

Effects on BER performance of down-link angle variation in SDMA
KISHIYAMA Yoshihisa, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1998, 1, 272, 272, 07 Sep. 1998
一般社団法人電子情報通信学会, Japanese

Co-channel Interference Suppression Using an Adaptive Array and an Interference Canceler
SUGIHARA Fumio, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 1998, 1, 509, 510, 07 Sep. 1998
一般社団法人電子情報通信学会, Japanese

A Study on Combining Coefficients in Spatial-Domain Path-Diversity Using an Adaptive Array
FUJISHIMA Kenzaburoh, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the Society Conference of IEICE, 1998, 1, 517, 518, 07 Sep. 1998
一般社団法人電子情報通信学会, Japanese

A Study on a Cascading Scheme of MMSE Adaptive Array and MLSE
HANAKI Akihito, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 98, 159, 39, 45, 29 Jun. 1998
Conventional cascading scheme of an adaptive array antenna and an MLSE requires the constraint condition fixing one element of the impulse response vector. Therefore, the path corresponding to fixed element is captured mainly, even when it arrives closely to interferense. As a result, the power of delayed paths cannot be utilized effectively. In this report, a novel cascading scheme is proposed to utilize the delayed paths more effectively. The results evaluating the output SINR from directional patterns show that the proposed scheme can reduce frquency of low output SINR. The bit error rate performanece in quasi-static Rayleigh fading channel calculated by computer simulation shows that the gain of the proposed scheme reaches about 3 dB in two-path plus interference model., 一般社団法人電子情報通信学会, Japanese

Channel Allocation in Mobile Communications Using the Genetic Algorithm
MURAKAMI Homare, OGAWA Yasutaka, OHGANE Takeo, Technical report of IEICE. RCS, 98, 159, 87, 94, 29 Jun. 1998
In this paper, we propose a method of fixed channel allocation using the genetic algorithm(GA). First, we describe the outline of GA. Then, we propose a scheme of allocation which does not generate interference. The method involves tournament selection, elitest preserving selection, and multipoint crossover. Furthermore, we exclude the allocation with the interference, We apply the method to 49 cell environment, 80 cell one and 101 cell one. From computer simulations, we show that the proposed scheme achieves resonable allocation. Also, we examine parameters which realize good convergence properties., 一般社団法人電子情報通信学会, Japanese

A Study on Degrees of Freedom and Multipath Suppression Performance of an Adaptive Array
KIKUCHI Tohru, OGAWA Yasutaka, OHGANE Takeo, Proceedings of the IEICE General Conference, 1998, 1, 125, 125, 06 Mar. 1998
一般社団法人電子情報通信学会, Japanese

A study on a cascading algorithm of adaptive array and equalizer
HANAKI Akihito, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 1998, 1, 534, 534, 06 Mar. 1998
一般社団法人電子情報通信学会, Japanese

A study on blocking rate performance of SDMA with 3-element adaptive array
TANAKA Daisuke, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the IEICE General Conference, 1998, 1, 535, 535, 06 Mar. 1998
一般社団法人電子情報通信学会, Japanese

Blocking Rate Performance of SDMA with a 3-element Adaptive Array
TANAKA Daisuke, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 97, 549, 95, 100, 20 Feb. 1998
Recently, SDMA (Space Division Multiple Access) concept has been proposed to improve channel efficiency. This paper describes SDMA using a 3-element adaptive array. A spatial correlation coefficient can be defined as a criterion to determine the possibility of triplicate channel allocation. When the average input SNR is more than 20dB, the users satisfying correlation coefficient of less than 0.89 can be accomodated in the same channel in 3-user SDMA model with assuming that each signal is incident from each own direction. The computer simulation shows sufficient blocking rate performance of the proposed channel allocation scheme., 一般社団法人電子情報通信学会, Japanese

Intelligent antenna technology
Ohgane Takeo, Ogawa Yasutaka, Proceedings of the IEICE General Conference, 759, 760, 1998
The Institute of Electronics, Information and Communication Engineers, Japanese

Considerations on Fixed Channel Assignment in Mobile Radio with Gentic Algorithm
Murakami Homare, Ogawa Yasutaka, Ohgane Takeo, Proceedings of the IEICE General Conference, 558, 558, 1998
一般社団法人電子情報通信学会, Japanese

Improvement of Spatial-Domain Path-Diversity Using an Adaptive Array
OGAWA Yasutaka, SASAKI Ryuhei, OHGANE Takeo, ITOH Kiyohiko, Proceedings of the Society Conference of IEICE, 1997, 1, 68, 68, 13 Aug. 1997
複数のウエイトベクトルを持つアダプティブアレーを用いて到来する各多重伝搬波を分離し、遅延時間を一致させた後合成する空間領域パスダイバーシチは伝送されるエネルギーを有効利用する方法である。多重波の中に近接して到来する伝搬波が含まれている場合、アダプティブアレーによるそれらの分離が良好に行なわれないため、等しい重みで合成した場合には、特性が劣化することがある。本報告では、多重波信号電力とアダプテイブアレーの誤差電力を考慮した荷重合成法を空間領域パスダイバーシチに適用することを提案する。, 一般社団法人電子情報通信学会, Japanese

Blocking rate performance of PDMA with an adaptive array and a directive antenna
Ohgane Takeo, Ogawa Yasutaka, Itoh Kiyohiko, Proceedings of the Society Conference of IEICE, 1997, 1, 69, 69, 13 Aug. 1997
チャネルの利用効率を向上させるため, 同一セル内で同一チャネルを複数のユーザに割り当てるPDMA(Path Division Multiple Access)あるいはSDMA(Space Division Multiple Access)という概念が提案されている. 筆者らはアダプティブアレーを用いたPDMA方式において, チャネル割り当て基準を示し, 呼損率特性の検討を行った. ここでは, 本方式と通常の指向性アンテナを用いた場合の比較を行う., 一般社団法人電子情報通信学会, Japanese

Multiuser detectable blind canceller for DS-CDMA in time-variant fading channel
YAMAZAKI Kenichirou, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1997, 1, 295, 295, 13 Aug. 1997
DS/CDMA方式では、逆拡散時の符号を直交化することにより、簡易なブラインドアルゴリズムで実現した干渉キャンセラであるOMFが検討されている。筆者らは緩やかな同期が保たれていると仮定し、マルチユーザ検出を容易に行なうことができるブラインド干渉キャンセラを提案したが、本稿ではこのブラインド干渉キャンセラにRLSアルゴリズムを用いた場合に演算量を削減できることを示し、時変フェージング時の特性を計算機シミュレーションを用いて評価する。, 一般社団法人電子情報通信学会, Japanese

A study on a multiple beam adaptive array in slotted ALOHA network
Ito Kuniaki, Ohgane Takeo, Ogawa Yasutaka, Proceedings of the Society Conference of IEICE, 1997, 1, 307, 307, 13 Aug. 1997
スロットアロハ方式において、基地局にマルチビームアダプティブアレーを用いてバケットの衝突を回避し、スループットを高める方式が提案されている。しかし、マルチビーム形成はスロットの到着時間差を利用しているため、長いプリアンブルを必要とする。そこで、本稿では、各ユーザが複数のPN符号をランダムに使用することにより、伝送効率の劣化を低減する手法を検討し、そのスループット特性を示す。, 一般社団法人電子情報通信学会, Japanese

Performance of Mobile Communication System Employing An Interference Canceller Combining Path Selecting Adaptive Array and MLSE
Doi Yoshiharu, Ohgane Takeo, Karasawa Yoshio, Proceedings of the Society Conference of IEICE, 1997, 1, 311, 311, 13 Aug. 1997
移動通信システムの高速化、大容量化を実現するためには、符号間干渉(Inter-Symbol Interference: ISI)と同一チャネル干渉(Co-Channel Interference: CCI)を克服しなけれげならない。筆者らはパス選択型アダプティブアレーとMLSE(Maximum Likelihood Sequence Estimation)を組み合わせてパスダイバーシチ利得が得られる干渉キャンセラを提案してきた。本稿では、提案した干渉キャンセラをTDMA/TDDセルラーシステムの基地局に適用すると共に、移動局には1シンボル遅延波までを等化できる等化器を搭載し、送信アダプティブアレーと受信等化器による下り回線の特性改善に関する検討・評価を行なったので報告する。, 一般社団法人電子情報通信学会, Japanese

A BER performance of diversity-combined DFE using differencial-LMS algorithm
HOSHINO Masayuki, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1997, 1, 404, 404, 13 Aug. 1997
陸上移動通信における波形歪みの対策として、様々な適応等化技術が検討されている。筆者らはこれまで、判定帰還型等化器(DFE)の適応アルゴリズムに差分量を盛り込む方式を提案してきた。一方でDFEは、ダイバーシチとの組み合わせにより良好な特性を示すことが報告されている。本稿では差分量近似を用いた適応アルゴリズムによりダイバーシチとの合成受信系を制御する方式を検討する。, 一般社団法人電子情報通信学会, Japanese

Down-link Performance of Moble Communication System Employing Interference Canceller Combining Diversity Branch Pre-selecting Adaptive Array and Cascaded Equalizer
DOI Yoshiharu, OHGANE Takeo, KARASAWA Yoshio, Technical report of IEICE. RCS, 97, 194, 27, 32, 25 Jul. 1997
We proposed a high-gained interference canceller that combines "diversity branches pre-selecting adaptive array" and "cascaded equalizer". The canceller can achieve sufficient path diversity gain even if incident angles of desired signal and short-delayed ISI to be diversity branches are very close, since the canceller pre-selects the signals with one antenna pattern. In this paper, we evaluate the down-link performance of mobile communication system that employs the canceller for base station and an equalizer for mobile station. The results show that sufficient path diversity gain is also obtained at down-link transmission when the velocity of mobile station is slow compared with the transmission rate., 一般社団法人電子情報通信学会, Japanese

Adaptive DFE control with differential LMS algorithm
HISHINO Masayoshi, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 97, 194, 33, 38, 25 Jul. 1997
High-speed and high-quality transmission in digital mobile radio requires simpler equalization without a tracking performande degradation. This paper proposes differential LMS algorithm for dicision feedback equalizer (DFE). This algorithm is based on higher order approximation of adaptive weight, and expected to track the fading channel described as simple Marcov process, more efficiently. Computer simulation shows that the proposed DFE can reduce the irreducible error almost half compared with the ordinary LMS-DFE. The diversity-combined DFE is also considered., 一般社団法人電子情報通信学会, Japanese

Multiuser detectable blind canceller for DS-CDMA
YAMAZAKI Kenichirou, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 97, 194, 57, 62, 25 Jul. 1997
This paper discusses a multiuser detectable blind canceller for DS-CDMA. With assuming the quasi-synchronous condition, the proposed canceller can reduce the configuration complexity by sampling the despread data at the same timing. The optimal weight can be estimated only with the received data and the correlation between the despread codes. Additionally the correlation matrix calculation can be reduced to almost half using the real symmetric matrix condition. The computer simulation shows the high performance of the proposed system even with its simple configuration., 一般社団法人電子情報通信学会, Japanese

Packet Radio Networks with a Multibeam Adaptive Array Using Multiple PN Codes
ITO Kuniaki, OHGANE Takeo, OGAWA Yasutaka, Technical report of IEICE. RCS, 97, 193, 103, 108, 24 Jul. 1997
Usually, the multibeam adaptive array requires the randomization of packet arrival timing for the multiple detection of collision packets. This paper proposes the PN code randomization in preamble, additionally. The computer simulation results show the improvement in throughput performance by randomizing both arrival timing scheduling and PN code selection, since the collision of both timing and code becomes less frequent. The proposed scheme can improve the transmission efficiency by reducing the preamble length and avoid the degradation due to low resolution in arrival timing detection., 一般社団法人電子情報通信学会, Japanese

A Study on Spatial-Domain Path-Diversity Using an Adaptive Array
SASAKI Ryuhei, OGAWA Yasutaka, OHGANE Takeo, ITOH Kiyohiko, Technical report of IEICE. RCS, 97, 193, 109, 116, 24 Jul. 1997
In high-speed digital mobile communications, energy per bit becomes small and multipath propagation causes performance degradation because of frequency-selective fading. In order to reduce distortion and to untilize transmitted signal power effectively, we have proposed spatial-dormain path-diversity using an adaptive array with sevral sets of complex weight vectors. We separate multipath signals, adjust the delay times and combine them. When multipath signals arrive from almost the same directions, the performance degrades. In this paper, we propose a signal combining method using the signal power and error power of the adaptive array. Simulation results show that the proposed scheme can provide much better BER performance even though some multipath signals arrive from almost the same directions., 一般社団法人電子情報通信学会, Japanese

A Study on BER Performance of Spatial-Domain Path-Diversity Using an Adaptive Array
SASAKI Ryuhei, OGAWA Yasutaka, OHGANE Takeo, ITOH Kiyohiko, Proceedings of the IEICE General Conference, 1997, 1, 699, 700, 06 Mar. 1997
高速ディジタル移動通信においては, 遅延時間差の長い多重波による周波数選択性フェージングが重大な問題になる. アダプティブアレーは, 遅延時間差の長い多重波ほど抑圧効果が良好になることから周波数選択性フェージング対策として期待されている. さらに, 遅延時間差の異なる信号を複数のウエイトベクトルで個別に受信し, 遅延時間差の補正を行った後, 合成する空間領域パスダイバーシチ受信によって多重波ひずみ補償と伝搬エネルギーの有効利用が図られる,. 本報告では, 高アンテナ基地局にアダプティブアレーを配置したとき, 即ち, 各多重波が複数の特定の方向から入射する場合におけるBER特性の検討を行った. BER特性は, フェージングの影響を受けていない場合と準静的フェージングを受けた場合に分けて, 計算機シミュレーションにより求めた., 一般社団法人電子情報通信学会, Japanese

Channel Assignment in Mobile Radio Communications with Genetic Algorithm.
村上誉, 小川恭孝, 大鐘武雄, 電気関係学会北海道支部連合大会講演論文集, 1997, 1997

Blocking rate performance of PDMA with an adaptive array
Ohgane Takeo, Ogawa Yasutaka, Itoh Kiyohiko, Proceedings of the IEICE General Conference, 477, 477, 1997
チャネルの利用効率を向上させるため, 同一セル内で同一チャネルを複数のユーザに割り当てるPDMA(Path Division Multiple Access)あるいはSDMA(Space Division Multiple Access)という慨念が提案されている. 筆者らはアダプティブアレーを用いたPDMA方式において, チャネル割り当て基準に関して検討し, 各信号のアンテナ入力ベクトルの相関が適当な基準であることを示した. ここでは, 本方式における呼損率特性に関して検討する., The Institute of Electronics, Information and Communication Engineers, Japanese

A study on a channel allocation scheme with an adaptive array in PDMA.
Ohgane Takeo, Ogawa Yasutaka, Itoh Kiyohiko, Proceedings of the Society Conference of IEICE, 1996, 1, 386, 386, 18 Sep. 1996
チャネルの利用効率を向上させるため,同一セル内で同一チャネルを複数のユーザに割り当てるPDMA(Path Division Multiple Access)あるいはSDMA(Space Division Multiple Access)という概念が提案されている.しかし,同一チャネル干渉を除去する手法を用いても,所要の誤り率特性を得られない状況が存在する場合には,同一チャネルを割り当てる基準が必要となる.ここでは,アダプティブアレーを用いたPDMA方式において,チャネル割り当て基準に関して検討する., The Institute of Electronics, Information and Communication Engineers, Japanese

Behavior of an adaptive array in the presence of multipath waves beyond degrees of freedom in land mobile communications
YAGI Hiroki, OGAWA Yasutaka, OHGANE Takeo, ITOH Kiyohiko, Proceedings of the Society Conference of IEICE, 1996, 1, 402, 402, 18 Sep. 1996
高速陸上移動通信においては、周囲の環境によって反射、回折、散乱のために多量波が発生し、著しい特性劣化が生ずる。これらの多重波を抑圧するために、アダプティブアレーを用いることが提案されている。一方、道路沿いの建物等が原因でこれらの多重波が広い範囲にわたって多数入射するため、アダプティブアレーの自由度を超える多重波が入射することがある。本稿ではパタンの自由度を超える多重波が入射するときのアダプティブアレーの特性をシミュレーションにより明らかにした。, 一般社団法人電子情報通信学会, Japanese

BER Characteristics of an Adaptive Array Base Station under Multiple Co-Channel Interference
KATOH Yoshihisa, OHGANE Takeo, OGAWA Yasutaka, ITOH Kiyohiko, Proceedings of the Society Conference of IEICE, 1996, 1, 406, 406, 18 Sep. 1996
近年、周波数資源の有効利用を目的として同一無線チャネル干渉除去技術が検討されている。本報告では、基地局にアダプティブアレーを配置することを提案し、基地局と移動局の間の見通しがほとんどない場合、即ち各到来波が基地局の周囲から多数入射する場合のBER特性の評価を計算機シミュレーションにより行った。, 一般社団法人電子情報通信学会, Japanese

Performance of High Gain Interference Canceller Combining Adaptive Array and MLSE in the Raleigh Fading Channel
Doi Yoshiharu, Ohgane Takeo, Proceedings of the Society Conference of IEICE, 1996, 1, 408, 408, 18 Sep. 1996
将来のディジタル移動通信の高速化大容量化にそなえ、符号間干渉(Inter-Symbol Interference:ISI)と同一チャネル干渉(Co-Channel Interference:CCI)が同時に存在する電波伝搬環境において、良好なディジタル無線通信を行なうための手法の確立が必要である。筆者らはアダプティブアレーアンテナとMLSE(Maximum Likelihood Sequence Estimation)を組み合わせてパスダイバーシチ利得が得られる干渉キャンセラを提案してきたが、これらの特性評価は、すぺて準静的なレイリーフェージング伝搬路で行われてきた。そこで、本稿では、動的なレイリーフェージング伝搬路における特性評価を行ったので報告する。, 一般社団法人電子情報通信学会, Japanese

A Study on a blind interference canceller for multiuser detection in DS-CDMA
YAMAZAKI Kenichirou, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1996, 1, 418, 418, 18 Sep. 1996
DS/CDMA方式では、リバースリンクにおいて干渉キャンセラを導入して容量増加をはかる検討が行われている。OMFは逆拡散時の符号を直交化することにより、簡易なブラインドアルゴリズムで実現した干渉キャンセラである。一方、基地局でマルチユーザ検出を考えた等化器も検討されているが、完全非同期条件では構成がやや複雑になる。そこで本稿では、緩やかな同期が保たれていると仮定し、マルチユーザ検出を容易に行なうことができるブラインド干渉キャンセラについて検討し、その評価を計算機シミュレーションにより行なう。, 一般社団法人電子情報通信学会, Japanese

A study on simplified algorithm for DFE
HOSHINO Masayuki, OHGANE Takeo, OGAWA Yasutaka, Proceedings of the Society Conference of IEICE, 1996, 1, 424, 424, 18 Sep. 1996
陸上移動通信では、波形歪みの対策として様々な適応等化技術が検討されている。そのうち判定帰還型等化器(DFE)は、演算量が比較的少なく1チップDSPでの実現も容易である。今後の伝送速度向上の必要性から、本稿では現在検討されているRLSと比較して各段に計算量の少ない、LMSの修正アルゴリズムによる等化を試みる。, 一般社団法人電子情報通信学会, Japanese

Performance of an Adaptive Array in the Presence of Multipath Waves beyond Degrees of Freedom in the Pattern
YAGI Hiroki, OGAWA Yasutaka, OHGANE Takeo, ITOH Kiyohiko, Technical report of IEICE. RCS, 96, 212, 9, 14, 08 Aug. 1996
In high-speed land mobile communications, multipath waves with delay difference are incident on a receiver because of reflection and scattering from surrounding objects. It is proposed to suppress the multipath waves with an adaptive array. In a case of a low antenna, multipath waves spatially spread widely because of buildings arround the antenna. It is considerd that multipath waves incident on the adaptive array exceed the number of degrees of freedom in the pattern in this scenario. This paper describes behavior of the adaptive array in the presence of multipath waves beyond the degrees of freedom. It is shown that the adaptive array regards multipath waves with 0.1〜0.3 symbol duration delay difference as a single wave. Thus, these multipath waves do not consume more than one degree of freedom., 一般社団法人電子情報通信学会, Japanese

The Peformance of the High Gain Interference Canceller Combining Adaptive Array and MLSE When Number of Antenna Elements Is Smaller Than That of Signals
DOI Yoshiharu, OHGANE Takeo, Technical report of IEICE. RCS, 96, 212, 27, 32, 08 Aug. 1996
A high gained interference canceller system combining adaptive array and MLSE that can obtain path diversity gain at low C/I had been proposed. It is considered that the system may work well when the number of the antenna elements is smaller than that of the signals, because the system synthesizes a desired signal and certain time delayed ISI (Inter Symbol Interference) simultaneously. In this paper, the performance of the system is calculated by computer simulation, when the number of the antenna elements is smaller than that of the signals. The results show that the system can reduce interferences, when the number of the antenna elements is equal or more than (number of signals)-(number of certain time delayed ISI from desired station)., 一般社団法人電子情報通信学会, Japanese

Co-Channel Interference Cancelling Characteristics by an Adaptive Array Base Station for Cellular Systems : In Case of Signals Arriving from Multiple Directions
KATOH Yoshihisa, OHGANE Takeo, OGAWA Yasutaka, ITOH Kiyohiko, Technical report of IEICE. RCS, 96, 29, 29, 34, 26 Apr. 1996
This paper proposes an adaptive array base station in order to reduce co-channel interference. The authors evaluated characteristics of SIR and SINR by computer simulation in case that signals arrived from multiple directions. As a result, the diversity gain was observed with the total number of incidents increasing even when the number of antenna elements was equal to one of incidents. The diversity gain was obtained when antenna elements were more than total incidents. In case of mobile station distributed equally within cell, 5% value of average SINR in downlink reached at about 16.3 dB when the cluster size was one. However, the severe degradation was caused by Rayleigh fading difference between uplink and downlink., 一般社団法人電子情報通信学会, Japanese

High Gain Interference Canceller Combining Adaptive Array and MLSE : Gain Improvement at Low C/I Synthesizing Desired and Delayed Signal Simultaneously
Doi Yoshiharu, Ohgane Takeo, Ogawa Eiichi, Proceedings of the IEICE General Conference, 1996, 1, 483, 483, 11 Mar. 1996
将来のディジタル移動通信の高速化、大容量化にそなえ符号間干渉(Inter-Symbol Interference:ISI)と同一チャネル干渉(Co-Channel Interference:CCI)が同時に存在する電波伝搬環境において、良好なディジタル無線通信を行なうための手法の確立が必要である考えられる。筆者らはアダプティブアレーアンテナとMLSEを組み合わせてパスダイバーシチ利得が得られる干渉キャンセルシステムを提案してきたが、平均C/Iが低くなると十分な利得が得られない欠点があった。本稿では、トレーニング信号とトレーニング期間のデータサンプリング間隔に工夫を加えることにより、低C/Iにおいても十分なパスダイバーシチ利得が得られる、アダプティブアレーとMLSEを組み合わせた干渉キャンセラを提案する。, 一般社団法人電子情報通信学会, Japanese

A study on the down-link power control of the adaptive array base station for cellular systems
Ohgane Takeo, Ogawa Yasutaka, Itoh Kiyohiko, Proceedings of the IEICE General Conference, 1996, 1, 504, 504, 11 Mar. 1996
セルラ方式において周波数利用効率を改善するためにアダプティブアレーによる同一チャネル干渉除去が提案されている.ここでは,さらに,下り回線において送信電力制御を行うことを検討する., 一般社団法人電子情報通信学会, Japanese

Interference Canceller Providing Path Diversity Gain Combining Adaptive Array Antennas and Maximum-Likelihood Sequence Estimation
DOI Yoshiharu, OHGANE Takeo, OGAWA Eiichi, Technical report of IEICE. RCS, 95, 490, 15, 21, 25 Jan. 1996
An interference canceller combining adaptive array and MLSE that can obtain path diversity gain at low C/I is porposed. Adaptive array of the canceller gets a desired signal and certain time delayed ISI (Inter Symbol Interference) simultaneously, because new training signal and data sampling timing in training period are employed. Terefore, the canceller shows path diversity gain using MLSE (maximum-likelihood sequence estimation). Average BER (Bit Error Rate) characteristics of the Canceller in quasi-static Rayleigh fading channel that has ISI and CCI (Co-Channel Interference) is calculated by computer simulation. The results show that the interferences were reduced and that path diversity gain was obtained at low C/I., 一般社団法人電子情報通信学会, Japanese

セルラ基地局の送受信アンテナ指向性制御による周波数利用効率の改善 (ディジタル陸上移動通信技術シリ-ズ)
大鐘 武雄, 通信総合研究所季報, 41, 4, 347, 353, Dec. 1995
電気通信振興会, Japanese

BER performance of the adaptive array base station for cellular systems
Ohgane Takeo, Proceedings of the Society Conference of IEICE, 1995, 1, 215, 215, 05 Sep. 1995
セルラ方式において周波数利用効率を改善するためにアダプティブアレーによる同一チャネル干渉除去を提案した.ここでは,誤り率特性について評価する., The Institute of Electronics, Information and Communication Engineers, Japanese

Characteristics of ISI and CCI Adaptive Canceller Combined of Adaptive Array Antennas and Maximum-Likelihood Sequence Estimator in Quasi-static Rayleigh Fading Channel
DOI Yoshiharu, OHGANE Takeo, OGAWA Eiichi, Technical report of IEICE. SAT, 95, 160, 19, 24, 20 Jul. 1995
ISI (Inter Symbol Interference) and CCI (Co-Channel Interference) adaptive canceller that is combined of adaptive array antennas and maximum-likelihood sequence estimator is proposed. Average BER (Bit Error Rate) characteristics of this adaptive canceller in quasi-static Rayleigh fading channel is calculated by computer simulation. Weiner Solution is employed for calculating weight vectors of adaptive array antennas. The results show that CCI was reduced by adaptive array antennas and that path diversity gain became remarkable with increasing C/I by the maximum-likelihood sequence estimator., 一般社団法人電子情報通信学会, Japanese

Measurements of Multipath Time Delay using Super-resolution PN Correlation Method
Doi Yoshiharu, Ohgane Takeo, Proceedings of the IEICE General Conference, 1995, 1, 27, 27, 27 Mar. 1995
多重遅延波による受信信号の歪みが、ディジタル移動通信においては、通信品質の劣化を引き起こす。我々は多重遅延波を高分解能に推定できるSuper-resolution PN correlation method (SPM)について、これまで計算機シミュレーションによってその分解能特性等を明らかにしてきた。本稿では、Delay Simulatorを用いた簡易な実験システムを構築し、SPMが持つ分解能の高さを実験的に検証し良好な結果が得られたので報告する。, 一般社団法人電子情報通信学会, Japanese

An ISI and CCI Canceller Consisted of Adaptive Array Antenna and Maximum Likelyhood Sequence Estimater
Doi Yoshiharu, Ohgane Takeo, Ogawa Eiichi, Proceedings of the Society Conference of IEICE, B, 277, 1995
ディジタル移動通信において周波数利用効率を高める方法として同一周波数の繰り返し利用は有効な方法であるが、そのためには同一チャネル干渉(Co-Channel Interference:CCI)を克服しなければならない。一方、符号間干渉波(Inter Symbol Interference:ISI)は所望波と同じ情報を持つため有効に利用すればパスダイバーシチ利得が得られる。そのため、CCIの除去能力をもつ適応等化器やパスダイバーシチ能力を持つアダプティブアレーの研究が行われている。本稿では、アダプティブアレーと等化器の組み合わせによるISI・CCIキャンセラを提案する。準静的環境におけるこのキャンセラの平均BER特性を計算機シミュレーションにより明らかにした。, 一般社団法人電子情報通信学会, Japanese

SIR Performance of the adaptive array base station under the 2-Path model for cellular systems
Ohgane Takeo, 電子情報通信学会秋季大会講演論文集, 1994, 1, 357, 357, 26 Sep. 1994
セルラ方式において周波数利用効率を改善するためにアダプティブアレーによる同一チャネル干渉除去を提案した.これまでは,移動局-基地局間は1つのパスで接続されていると仮定してきた.ここでは,2つの異なったパスを持つ場合についてSIR特性を評価する., The Institute of Electronics, Information and Communication Engineers, Japanese

Resolution characteristics of SPM(Superresolution PN correlation Method)
Doi Yoshiharu, Ohgane Takeo, IEICE technical report. Antennas and propagation, 94, 38, 45, 52, 19 May 1994
Multipath fading causes severe performance degradation in the broad band digital mobile radio.PN code correlation method is a general way to measure the multipath environment.However,it can not resolve the paths with the time delay defference shorter than the PN code chip length.In order to improve the,resolution performance,SPM has been proposed.SPM can achieve higher resolution by employing the MUSIC algorithm and spatial smoothing method.In this paper,the resolution characteristics of SPM is evaluated in detail.The obtained resolution reaches 40 times higher than that of PN code correlation method with the specified parameters.More improvement will be available with refining the several parameters., 一般社団法人電子情報通信学会, Japanese

セルラ基地局のアンテナ指向性制御による周波数利用効率の改善
大鐘武雄, 信学技報, 1993

4.マイクロセルにおける分散制御アルゴリズムによるダイナミックチャンネル割当の呼損率特性(<特集>ICC'92)
渡辺 敏英, 大鐘 武雄, テレビジョン学会誌, 46, 10, 1361, 1361, 20 Oct. 1992
一般社団法人映像情報メディア学会, Japanese

陸上移動通信におけるCMAアダプティブアレ-の選択性フェ-ジング補償特性 (ディジタル陸上移動通信技術<特集>) -- (広帯域ディジタル伝送技術)
大鐘 武雄, 通信総合研究所季報, 37, 1, p137, 145, Feb. 1991
電気通信振興会, Japanese

市街地及び郊外地における陸上移動多重伝搬路の諸特性 (ディジタル陸上移動通信技術<特集>) -- (陸上移動伝送路の特徴と課題)
大鐘 武雄, 通信総合研究所季報, 37, 1, p19, 27, Feb. 1991
通信総合研究所, Japanese

フェ-ジング対策技術開発用シミュレ-ションプログラム (ディジタル陸上移動通信技術<特集>) -- (技術開発支援評価システム)
大鐘 武雄, 三瓶 政一, 神尾 享秀, 通信総合研究所季報, 37, 1, p177, 186, Feb. 1991
電気通信振興会, Japanese

評価実験装置--ディジタル信号処理装置 (ディジタル陸上移動通信技術<特集>) -- (技術開発支援評価システム)
神尾 享秀, 三瓶 政一, 大鐘 武雄, 通信総合研究所季報, 37, 1, p201, 207, Feb. 1991
電気通信振興会, Japanese

陸上移動多重伝搬路 (ディジタル陸上移動通信技術<特集>) -- (陸上移動伝送路の特徴と課題)
大鐘 武雄, 関沢 信也, 通信総合研究所季報, 37, 1, p13, 17, Feb. 1991
電気通信振興会, Japanese

A Development of GMSK/TDMA System with CMA Adaptive Array in Land Mobile Communications : An Outline
OHGANE T., 1989 Autumn National Convention Record of IEICE, B, 511, 1989

都市内多重伝搬路におけるCMAアダプティブアレーの特性-GMSK信号伝送の場合-
武雄大鐘, 信学技報, 87, 47, 54, 1987

わかりやすいMIMOシステム技術　　　　　　　　　　　　　　　
大鐘武雄, 小川恭孝
オーム社, Jun. 2009, [Joint work]

WiMAX教科書　　　　　　　　　　　　　　　
庄納崇編著, 6.2
インプレスR&D, Jul. 2008, [Contributor]

適応フィルタ理論　　　　　　　　　　　　　　　
鈴木博翻訳主幹, 第6章
科学技術出版, Nov. 2000, [Joint translation]

移動通信　　　　　　　　　　　　　　　
笹岡秀一編著, 第12章
オーム社, May 1998, [Contributor]

無線信号のセンシングと通信の統合を実現する大規模MIMOシステムの高度化
科学研究費助成事業
01 Apr. 2024 - 31 Mar. 2027
西村 寿彦, 大鐘 武雄
日本学術振興会, 基盤研究(C), 北海道大学, 24K07470

細分化深層学習による到来方向推定と実測検証
科学研究費助成事業
01 Apr. 2023 - 31 Mar. 2027
大鐘 武雄, 筒井 弘, 西村 寿彦
各到来波数に対応した特化型DNNの設計を図ることが大きな目標であった．そのため，まず3波到来環境に適したDNNを構築した．さらに，SN比に応じて訓練したSNR特化型DNNで推定すると特性が向上することから，あるSNRと推定波数における特化型DNNの構築を図った．次に，これを用いて，2波到来環境と3波到来環境に対応可能なシステムを構築するため，到来波数を推定するDNNとSNRを推定するDNNとを用意し，これらの推定結果を基に，最適な特化型DNNを選択する手法を採用した．その結果，2波到来環境で約95%以上に，3波到来環境においても約85%の成功率を達成できた．しかし，低SNR環境や，3波到来環境の成功率はまだ不十分であることも明らかとなった．
低SNR環境での問題は，データに含まれる雑音が無駄な入力となっているということである．そこで，入力データに対して主成分分析を行い，SNRに応じて入力次元を削減することを新たに提案した．その結果，SNR=0dBの環境において，推定成功率を約10%から60%以上に改善することができた．
3波到来環境においては，推定失敗例を解析した結果，3波が約20度以内の範囲に集中している場合に推定誤りが多く発生していることがわかった．そこで，3波が約20度以内の範囲に集中している場合を想定した近接波特化型DNNを構築し，通常の特化型DNNでの推定結果において3波が約20度以内の範囲に集中している場合には，前記の近接波用DNNを再度適用し直すことを行なった．これにより，推定成功率を約99%に向上することができた．
実測用USRPに関しては，Lora変調を用いて通信実験を行うことができた．
日本学術振興会, 基盤研究(B), 北海道大学, 23K26101

細分化深層学習による到来方向推定と実測検証
科学研究費助成事業
01 Apr. 2023 - 31 Mar. 2027
大鐘 武雄, 筒井 弘, 西村 寿彦
日本学術振興会, 基盤研究(B), 北海道大学, 23H01406

大規模MIMOシステムにおけるルースビームフォーミングの実現
科学研究費助成事業 基盤研究(C)
01 Apr. 2020 - 31 Mar. 2023
西村 寿彦, 大鐘 武雄
マルチユーザ大規模MIMOシステムでは, 基地局に100 素子以上の送信アンテナ素子を配置することに伴い, ウェイト形成の計算量が著しく増大する. このため,送信に使用するアンテナを選択するのみでウェイトを生成するルースビームフォーミングという手法が提案されている. 今年度は, 主に以下の2点について検討を行った．
一つ目は，ルースビームフォーミングの送信アンテナ選択について，前年度は機械学習や遺伝的アルゴリズムを用いて準最適解を得ていたが，新たに量子アニーリングを導入した．量子アニーリングは，組み合わせ最適化問題に特化したクラウドソルバーとして商用利用されるようになり，近年その用途について多くの検討が始まってきた．ルースビームフォーミングは送信アンテナを使うか使わないかの2値のベクトルを通信容量が最大となるように最適化することで実現できることから，この量子アニーリングが有用なソルバーとなりえると考えた．検討の結果，前年度に用いた機械学習や遺伝的アルゴリズムに比べて，極めて短時間で同程度の性能を得られる可能性を確認した．
二つ目は，マルチユーザ大規模MIMOシステムについて，ルースビームフォーミングと分散アンテナシステムの類似性から，分散大規模MIMOシステムにおけるアンテナ選択及びユーザ選択の検討を行った．屋内環境における大規模分散アンテナシステムを想定し，ユーザ選択及びアンテナ選択の効果を評価した．検討したモデル内では，アンテナ選択については有意な改善は見られなかったものの，ユーザ選択の効果は示された．
日本学術振興会, 基盤研究(C), 北海道大学, 20K04460

Detection of Large Scale and Overloaded Signals from Massive IoT devices Based on Belief Propagation
Grants-in-Aid for Scientific Research
01 Apr. 2018 - 31 Mar. 2021
Ohgane Takeo
For accommodating massive IoT devices in a common channel, we developed methods which can correctly detect all of the signals with much fewer observations and much lower complexity. We newly proposed convex optimization with ADMM based on discreteness and group sparseness and improved Gaussian belief propagation and approximate message passing with parameter optimization using deep unfolding. Consequently, we succeeded to establish light-weight and high-performance signal detectors.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 18H03765

確率伝搬法による大規模・過負荷MIMO信号検出を用いた超多数IoTデバイスの収容　　　　　　　　　　　　　　　
科学研究費補助金(基盤研究(A))
Apr. 2018 - Mar. 2021
大鐘武雄
文部科学省, Principal investigator, Competitive research funding

大規模MIMOシステムにおけるアンテナ選択によるビーム制御　　　　　　　　　　　　　　　
科学研究費補助金(基盤研究(C))
Apr. 2017 - Mar. 2020
西村寿彦
文部科学省, Competitive research funding

大規模アナログ結合を有する2 部グラフ理論の確立　　　　　　　　　　　　　　　
科学研究費補助金(基盤研究(A))
Apr. 2015 - Mar. 2018
大鐘武雄
文部科学省, Principal investigator, Competitive research funding

Routing for wireless mesh networks with beam/null control
Grants-in-Aid for Scientific Research
Apr. 2012 - Mar. 2015
OHGANE Takeo, OGAWA Yasutaka, NISHIMURA Toshihiko, WEBBER Julian
Wireless mesh networks are considered as an efficient candidate for a substitution of communication infrastructure in disaster situations. Such a network is suffered by mutual interferences between nodes since all nodes are reachable. We studied a cross layer processing to exploit this overreach by using beam/null control at each node. Specifically, beam/null control and its experimental test using USRP in the layer 2 were carried out. In addition, we clarified that the alternative routing with beam/null control in the layer 3 improved the throughput performance.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 24360144

圧縮サンプリング手法を使用したマルチバンドMIMOレーダの検証実験　　　　　　　　　　　　　　　
戦略的情報通信研究開発推進制度 (SCOPE)
Nov. 2013 - Mar. 2014
西村 寿彦
総務省, Competitive research funding

電波伝搬測定に基づくMIMO通信容量の評価とその改善に関する研究　　　　　　　　　　　　　　　
科学研究費補助金(基盤研究(B))
Apr. 2011 - Mar. 2014
小川恭孝
文部科学省, Competitive research funding

Study on Direction-of-Arrival Estimation with Metaheuristics
Grants-in-Aid for Scientific Research
2010 - 2012
OHSHIMA Kohzoh, MURASMOTO Mitsuru, OGAWA Yasutaka, KASHIWA Tatsuya, TAGUCHI Kenji, IMAI Suguru, OHGANE Takeo, NISHIMURA Toshihiko
In this research, we tried to apply Genetic Algorithm, Immune Algorithm andParticle Swarm Optimization to high resolution direction of arrival estimation.When the incident wave in the near field sources becomes a spherical wave, the complex calculation is needed with theMUSIC method though the incident wave was assumed to be a plane wave in conventional ways ofDOA estimation.As results of simulations, we confirmed the accuracy of direction of arrival estimation with metaheuristics and have shown its effectiveness.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Asahikawa National College of Technology, 22560400

Relative position detection of radio terminals adapting a MIMO rada
Grants-in-Aid for Scientific Research
2010 - 2012
NISHIMURA Toshihiko, OGAWA Yasutaka, OHGANE Takeo
In this research, the method of relative position detection oftransmission and reception terminals, i.e. realization of a multi-input-multi-output (MIMO) radar, has examined by using the MIMO system which carries multi antenna elements in both terminals. As a problem, when many terminals existed, or when a multipass wave existed, many interference waves will enter into a receiving side, and it was predicted that the position estimate became difficult. Then, the technique of the position estimate of the terminals was developed by using the broadband signals. The broadband signal is divided into multi narrow band signals. Then, a conventional direction of arrival estimation method is adopted by rising from low frequency without the influence of a grating robe to the high frequency from which high resolution is obtained
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Coinvestigator not use grants, Competitive research funding, 22560355

Distributed network optimization based on information potential
Grants-in-Aid for Scientific Research
2009 - 2011
OHGANE Takeo, OGAWA Yasutaka, NISHIMURA Toshihiko, WEBBER Julian
In the wireless mesh network with nodes capable beam-forming, we have obtained the following three major achievements. (1) The approximate solution for maximizing sum-capacity has been developed and its high performance has been shown in network-coded links. (2) An suboptimum routing has been proposed for a wireless mesh network with nodes capable beam-forming and its high throughput performance has been indicated. (3) We have derived an approximated solution for the optimum beam-forming at the source node in a two-step relay.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 21360175

Study on Highly Reliable Radio Communications Using Transmit Beam-forming with a Virtual Antenna Array
Grants-in-Aid for Scientific Research(基盤研究(B))
2007 - 2009
Yasutaka OGAWA, Takeo OHGANE, Toshihiko NISHIMURA
Future mobile communications need to use a higher frequency band to accommodate a wider frequency bandwidth. In a higher frequency band, the attenuation of electromagnetic waves is severely large. In an uplink channel, we may have difficulties to realize reliable transmission because the transmit power of a user terminal is limited due to battery use. In this study, we have proposed a virtual antenna array in which plural user terminals cooperate with each other and operate as a single terminal. The virtual antenna array forms transmit beams toward a base station. We have proposed several e...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 19360168

疑似固有ビーム伝送技術の研究開発　　　　　　　　　　　　　　　
戦略的情報通信研究開発推進制度 (SCOPE)
2007 - 2008
大鐘武雄
総務省, Principal investigator, Competitive research funding

Studies on High-speed Radio Transmission Using MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) Systems
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2005
Yasutaka OGAWA, 西村 寿彦, 大鐘 武雄
1. Evaluation of the channel estimation and BER performance using an experimental system :An OFDM demodulation system was built up using DSP boards. Experimentally, we validated the OFDM channel estimation scheme proposed by our group. The channel was calculated by FFT applying to the impulse response obtained by the minimum square error method in the time domain. Then, we evaluated the bit error rate (BER) performance of the proposed OFDM system. Also, we examined an ordered successive detection method and transmission with error correcting codes.2. Joint estimation of channel and frequenc...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 15360198

固有ビーム分割多重方式の実現に関する研究　　　　　　　　　　　　　　　
戦略的情報通信研究開発推進制度 (SCOPE)
2003 - 2004
小川恭孝
総務省, Competitive research funding

A Study on transmit power control per subcarrier in OFDM
Grants-in-Aid for Scientific Research(基盤研究(C))
2001 - 2003
Takeo OHGANE, 山本 学, 西村 寿彦, 小川 恭孝
In multiple-input multiple-output systems, most common application is space division multiplexing (SDM) where individual data substreams are transmitted from multiple antennas with the same power and the same rate. SDM applications assume that MIMO channel information in not available at the transmitter. If we know all of MIMO channel information, it is possible to assign matched beam to each substream where the optimum weight for beamforming is obtained by singular value decomposition of MIMO channel matrix. We call SDM with eigenbeam-forming as E-SDM, hereafter. In E-SDM, we have to consi...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 北海道大学, Principal investigator, Competitive research funding, 13650390

動的チャネル割り当てを応用した空間分割多元接続(SDMA)方式
科学研究費補助金(奨励研究(A))
1998 - 1999
大鐘 武雄
陸上移動通信では,周波数利用効率の向上のためにサービスエリアを複数のセルに分割するセルラ方式が適用されている.通常は,使用できるチャネルをあらかじめそれぞれのセルに割り当てしておく固定チャネル割り当てが行われている.しかし,トラフィックの空間的な不均一性により,あるセルではチャネルが不足し,あるセルでは余剰が生じるような場合が生じてしまう.これを解決する手法として,動的にチャネルを割り当てる手法が提案されている.一方,同一セル内の複数のユーザに同一チャネルを割り当てるSDMA方式も,周波数利用効率の改善効果が著しい.SDMA方式は基地局に干渉除去のためのアダプティブアレーを必要とする.そこで,アダプティブアレーを他セルからの同一チャネル干渉除去に用いるものと,SDMA方式を併用した場合とのチャネル利用効率を,動的チャネル割り当てを想定してシミュレーションにより評価した.なお,動的チャネル割り当てとして,ランダム割り当て方式を仮定した.その結果,基地局がすべてのチャネルを使用できる場合,SDMA方式を併用してもほとんど利用効率の改善効果が得られないことがわかった.しかし,PHSのように基地局で利用できるチャネルに制限がある場合には,SDMA方式併用による大きな改善効果が得られることが明らかになった.このように,現実的なモデルを想定した場合には,SDMA方式が有効であると言える.
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 10750258

人工生命の概念に基づく通信システムの最適化に関する基礎研究
科学研究費補助金(萌芽的研究)
1996 - 1998
小川 恭孝, 大鐘 武雄, 西村 寿彦
本研究は、種々の通信システムの最適化問題に人工生命の概念を導入することを目的としたものである。本研究においては、主に遺伝的アルゴリズムを用いた、移動通信の固定チャネル割り当て、ATM網のルーテイング、および、フェーズドアレーアンテナの低サイドローブ化について検討を行った。さらに、移動通信の最適受信法についても研究した。以下にその実施結果を述べる。1. セルラー方式を用いた移動通信の固定チャネル割り当ては組み合わせ論的問題になるため、一般に膨大な演算が必要とされる。本研究では、まず、遺伝的アルゴリズムを適用することにより、チャネル割り当てを実現する方法の定式化を行った。ここで、遺伝的アルゴリズムの交鎖においてチャネル間干渉が生じない染色体構造を提案するなど、チャネル割り当てへの遺伝的アルゴリズムの適用にいくつかの新知見を得た。2. ATM網のリンクコストを最小化する最適アルゴリズムも組み合わせ論的問題となる。このようなルーティングを遺伝的アルゴリズムにより実現する方法の定式化を行い、シミュレーションにより本アルゴリズムの評価を行った。3. フェーズドアレーアンテナのサイドローブレベルを低減する励振位相を求めることは非線形最適化問題となる。各移相器の励振位相を連結したものを染色体とみなし、交鎖、突然変異、選択の遺伝的アルゴリズムの操作を適用した。これにより、短い演算時間でフェーズ...
文部科学省, 萌芽的研究, 北海道大学, Coinvestigator not use grants, Competitive research funding, 08875073

A Study on Millimeter-Wave Antenna Technology
Grants-in-Aid for Scientific Research(一般研究(A), 基盤研究(A))
1995 - 1998
Kiyohiko ITOH, 石井 望, 大鐘 武雄, 大宮 学, 小川 恭孝, 山本 学
(1) A novel quasi-optical antenna mixer has been developed. The antenna mixer consists of a coplanar waveguide fed dual-frequency microstrip antenna and Schottky-barrier diode connected to the end of the guide. A novel beam scanning system in which the phase shifter is not used has been realized using the antenna mixer.(2) An image NRD guide (iNRDG) has been proposed as a low-loss guide in the millimeter-wave band. A transverse slot cut on the image plate of the iNRDG has been developed as a novel millimeter-wave antenna. To design the array of the transverse slot, an analysis and a measure...
Ministry of Education, Culture, Sports, Science and Technology, 一般研究(A), 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 07405019

空間領域信号処理によるセルラ方式通信システムの周波数利用効率の改善
科学研究費補助金(奨励研究(A))
1996 - 1996
大鐘 武雄
現在の移動通信において,PHSや,携帯電話に代表される移動通信への需要の増加はめざましく,周波数の確保が困難な状況になってきている.これらのシステムはセルラ方式により,同一周波数を空間的に離したゾーンで繰り返し使用することにより,周波数の効率的な利用を図っている.したがって,これ以上の改善のためには,同一周波数を使用する他チャンネルからの干渉を何らかの方法により軽減しなければならない.本研究では,セルラ方式における周波数利用効率の改善を目指して,低アンテナ高の基地局において同一チャネル干渉を軽減させる手法に関して検討を行った 以下にその実施結果を述べる.1.低アンテナ基地局では各アンテナ間でのフェージング相関がない伝搬モデルを使用する必要がある.2.アダプティブアレーを低アンテナ基地局に適用することにより干渉を十分除去できる.3.総到来波数がアンテナ本数よりも多い場合には余剰自由度によりダイバーシチ利得が得られる.4.総到来波数がアンテナ本数と等しい場合,総到来波数が大きくなると実効的な余剰自由度が発生し,若干のダイバーシチ利得が得られる.ただし,SN比が小さい場合にのみ観測される.5.フェージング変動が速い場合には上下回線のフェージング相関が小さくなるため,特性の劣化が生じる.送信時のウェイトの推定を行うことによりこの劣化を低減することができる.上記のように,本研究により同...
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 08750410

Research on Active Transmitting and Receiving Antennas in Microwave Energy Transmission Systems
Grants-in-Aid for Scientific Research(試験研究(A), 基盤研究(A))
1994 - 1996
Kiyohiko ITOH, 石井 望, 大宮 学, 小川 恭孝, 大鐘 武雄
The purpose of our research project is to develop active antenna systems for receiving or transmitting microwave power in space solar power satellite systems. The following results are based on the patent obtained from the previous research project. First, the concept of "the virtual experiment environment" is proposed in order to design the antenna elements and the microwave circuits at the frequency of 2.45GHz. The microwave circuits are composed the transmitting active antenna system which uses the phase-control algorithm for beam steering. The cavity-backed slot antenna is proposed as t...
Ministry of Education, Culture, Sports, Science and Technology, 試験研究(A), 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 06505002

High-resolution Radar Imaging Using Two-dimensional Superresolution Techniques
Grants-in-Aid for Scientific Research(一般研究(C))
1994 - 1995
Yasutaka OGAWA, 石井 望, 大宮 学, 伊藤 精彦, 大鐘 武雄
Radar imaging is an important technique to identify a radar target . Resolution is, however, limited because the two-dimensional Fourier transform has been employed. The purpose of this study is to establish a method whichgives high-resolution radar imaging, and to develop related techniques. Major results obtained in the research period are as follws :1.A superresolution technique using a two-dimensional MUSIC algorithm was developed for the radar imaging . It has high-resolution capabilities.2.The two-dimensional MUSIC is not reliable when there are many signals. We introduced spatial-dom...
Ministry of Education, Culture, Sports, Science and Technology, 一般研究(C), 北海道大学, Coinvestigator not use grants, Competitive research funding, 06650397