Details of a Researcher - TAKAHATA, Fumio

写真a

TAKAHATA, Fumio

Affiliation

Faculty of Science and Engineering

Job title

Professor Emeritus

Degree

工学博士 ( 早稲田大学 )
Doctor of Engineering
博士(工学) ( 早稲田大学 )

Homepage URL

http://www.takahata.comm.waseda.ac.jp/

Research Experience

1988

-

　

Professor, School of Science and Engineering, Waseda University
1974

-

1988

KDD R&D Laboratories, Researcher

Education Background

　

-

1974

Waseda University Graduate School of Science and Engineering Major in Electrical Engineering
　

-

1972

Waseda University School of Science and Engineering Department of Electronics and Communication Engineering

Professional Memberships

　

　

　

Institute of Image, Information and Television Engineers (ITE)
　

　

　

Institute of Image Information and Television Engineers (ITE)
　

　

　

Institute of Electrical and Electronics Engineers (IEEE)
　

　

　

Institute of Electronics, Information and Communication Engineers (IEICE)
　

　

　

Institute of Electronics, Information and Communication Engineers (IEICE)

Research Interests

Wireless Communications, Digital Signal Processing, Telecommunication Engineering

Awards

「電波の日」総務大臣表彰

2017.06
電子情報通信学会通信ソサイエテイ優秀論文賞

2017.05
日本放送協会放送文化賞

2016.03
日本ITU協会賞功績賞

2010.05
「平成20年度情報化促進貢献個人」総務大臣表彰「情報化促進部門」

2008.10
「情報通信月間」関東総合通信局長表彰

2005.06
電子情報通信学会フェロー

2003.09

▼display all

Papers

On Reduction of Computational Complexity in MLD by applying Search Algorithms

Ken Nikaido, Akira Kato, Fumio Takahata

Proceedings of the 2017 IEICE General Conference B-5-3 2017.03 [Refereed]
On Computational Complexity in Lattice Reduction-Sphere Encoding-Vector Perturbation

Akira Kato, Fumio Takahata

Proceedings of the 2017 IEICE General Conference B-5-41 2017.03 [Refereed]
An Adaptive Switching Scheme of OFDM Channel Estimation Direction based on Log Likelihood Ratio

Futoshi Fukuda, Fumio Takahata

Proceedings of the 2017 IEICE General Conference B-5-72 2017.03 [Refereed]
On Bit Error Performance of Polar Codes over Additive White Gaussian Noise Channels

Masaaki Ito, Fumio Takahata

Proceedings of the 2016 Communications Society, IEICE Conference B-5-17 2016.09 [Refereed]
An Application of Sorted QR Detection to LR-SE-VP(Lattice Reduction-Sphere Encodhing-Vector Perturbation)

Akira Kato, Fumio Takahata

Proceedings of the 2016 Communications Society, IEICE Conference B-5-41 2016.09 [Refereed]
A Search Algorithm of Optimal Perturbation Vectors by applying Ray Detection in Real Signal Space to MU-MIMO NLP based on LR-THP

Kazuki Imamura, Fumio Takahata

IEICE Transactions on Communications J99-B ( 8 ) 591 - 601 2016.08 [Refereed]
Proposal of An Adaptive Allocation Method of Scattered Pilots for Fading Variation

Takuro Yokoyama, Fumio Takahata

IEICE Transactions on Communications J99-B ( 6 ) 467 - 469 2016.06 [Refereed]
B-5-99 On Effective Likelihood in FEC Decoding for Coded MIMO-OFDM Systems

Tamada Yuko, Takahata Fumio

Proceedings of the IEICE General Conference 2016 ( 1 ) 492 - 492 2016.03 [Refereed]

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B-5-111 An Application of Best-First Search to Sphere Encoding-Vector Perturbation in Downlink of MU-MIMO

Kato Akira, Imamura Kazuki, Takahata Fumio

Proceedings of the IEICE General Conference 2016 ( 1 ) 504 - 504 2016.03 [Refereed]

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B-5-112 A Calculation Reduction Scheme for Non-Linear Precoding in Downlink of MU-MIMO

Imamura Kazuki, Takahata Fumio

Proceedings of the IEICE General Conference 2016 ( 1 ) 505 - 505 2016.03 [Refereed]

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A novel modulo loss suppression scheme employing theoretical BER formula for MU-MIMO THP systems

Nishimura, Kei, Maruko, Tomoki, Tomeba, Hiromichi, Onodera, Takashi, Kubota, Minoru, Maehara, Fumiaki, Takahata, Fumio

2015 IEEE 82nd Vehicular Technology Conference, VTC Fall 2015 - Proceedings 2016.01 [Refereed]

　View Summary

© 2015 IEEE. This paper proposes a novel modulo loss suppression scheme employing a theoretical BER formula for multi-user multiple-input multiple-output (MU-MIMO) Tomlinson-Harashima Precoding (THP) systems. The main feature of the proposed approach is to control the constellation distance by using the simple theoretical bit error rate (BER) formula in order to overcome the modulo loss. Behind this proposal, there is an interesting fact that the BER performance is dependent on the influence of both the thermal noise and the modulo loss and that its influence is determined by the constellation distance. In the proposed approach, we newly derive a theoretical simple BER formula for MU-MIMO THP and then find out the optimal constellation distance to suppress the modulo loss. The effectiveness of the proposed scheme is demonstrated in comparison to the traditional MU-MIMO THP with fixed distance by means of computer simulations.

DOI
Performance Evaluation of An Adaptive Allocation Method of Scattered Pilots for Fading Variation

Takuro Yokoyama, Fumio Takahata

IEICE Technical Report RCS2015-319 213 - 218 2016.01 [Refereed]
Optimization of VP's in Downlink MU-MIMO NLP based on LR-THP

Kazuki Imamura, Fumio Takahata

IEICE Technical Report RCS2015-285 ( 394 ) 31 - 36 2016.01 [Refereed]

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An Adaptive Channel Estimation Scheme with Scattered Pilots for Fading Condition

Takuro Yokoyama, Fumio Takahata

IEICE Transactions on Communications J98-B ( 8 ) 804 - 817 2015.08 [Refereed]
BS-2-6 Study on Packet Transmission Technique for Non-linear MU-MIMO Transmission

TOMEBA Hiromichi, YOSHIMURA Tomoki, ONODERA Takashi, MAEHARA Fumiaki, TAKAHATA Fumio

Proceedings of the Society Conference of IEICE 2015 ( 1 ) 41 - 42 2015.08 [Refereed]
B-5-18 A Calculation Reduction Scheme for Lattice Reduction-Sphere Encoding-VP in Downlink of MU-MIMO

Imamura Kazuki, Takahata Fumio

Proceedings of the Society Conference of IEICE 2015 ( 1 ) 280 - 280 2015.08 [Refereed]

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B-5-7 An Adaptive Allocation Method of Scattered Pilots for Fading Variation

Yokoyama Takuro, Takahata Fumio

Proceedings of the Society Conference of IEICE 2015 ( 1 ) 269 - 269 2015.08 [Refereed]

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B-5-86 An Application of Lattice Reduction to Sphere Encoding-Vector Perturbation in Downlink of MU-MIMO

Imamura Kazuki, Takahata Fumio

Proceedings of the IEICE General Conference 2015 ( 1 ) 441 - 441 2015.02 [Refereed]

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MU-MIMO THPにおいてmodulo誤りの影響を低減するHybrid ARQ方式

竹渕翔矢, 丸小倫己, 留場宏道, 小野寺毅, 窪田稔, 前原文明, 髙畑文雄

電子情報通信学会論文誌B J98-B ( 1 ) 65 - 76 2015.01 [Refereed]
B-5-40 A Perfonnance Evaluation of OFDM Transmission depending on Scattered Pilot Allocation in Fading Conditions

Yokoyama Takuro, Takahata Fumio

Proceedings of the Society Conference of IEICE 2014 ( 1 ) 311 - 311 2014.09 [Refereed]

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B-5-11 An application of Multiple Sphere Encoding with Sorted QR Decomposition to Downlink MU-MIMO VP

Sasaki Shunsuke, Takahata Fumio

Proceedings of the Society Conference of IEICE 2014 ( 1 ) 282 - 282 2014.09 [Refereed]

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An Application of MRC and VP to BD in Downlink of MU-MIMO

Kazuki Imamura, Fumio Takahata

Proceedings of the 2014 Communications Society, IEICE Conference B-5-12 2014.09 [Refereed]
Vector Perturbation using Signal Space Conversion Assisted Vector Ranking Algorithm

Hiromichi Tomeba, Takashi Onodera, Minoru Kubota, Fumiaki Maehara, Fumio Takahata

IEEE Wireless Communications and Networking Conference WCNC conference 2014.04 [Refereed]
An application of Multiple Sphere Encoding to Downlink MU-MIMO VP

SASAKI Shunsuke, TAKAHATA Fumio

Technical report of IEICE. RCS 113 ( 456 ) 505 - 510 2014.02 [Refereed]

　View Summary

This paper proposes the computational complexity reduction technique for the Downlink Multi-User Multiple Input Multiple Output (Downlink MU-MIMO) using Vector Perturbation (VP). VP is one of the Non-Linear precoding methods, which minimize the required transmission power, by searching the optimal perturbation vector among the infinite number of perturbation vector candidates. However, its computational complexity increases exponentially with the number of spatial multiplexing mobile terminals. To reduce the complexity of VP, Sphere Encoding VP (SE-VP) has been proposed, which is based on sphere search algorithm, but its computational complexity remains relatively high. In this paper, we propose Multiple Sphere Encoding VP (MSE-VP), which uses multiple spheres, and clarifies its transmission performance and computational complexity by computer simulation.

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An Adaptive Dual-mode DFCE with Scattered Pilots for Fading Condition

SUMITANI Sho, TAKAHATA Fumio

Technical report of IEICE. RCS 113 ( 456 ) 437 - 442 2014.02 [Refereed]

　View Summary

In an application of a dual-mode decision feedback channel estimation to a COFDM transmission with scattered pilot symbols, there would be three kinds of possible methods to process or select forward and backward channels estimated values. These are to average the values, to select one direction values from both direction values based on a path metric value of Viterbi decoding, and to select a value from values based on LLR (Log-Likelihood Ratio) value. Effective methods to obtain accurate estimated channel values in frequency and time directions depend on a fading condition characterized respectively by a delay spread and Doppler frequency. An exact detection of fading conditions requires a complicated signal processing for unstable and variable delay spread and Doppler frequency and is desirable to be removed from the channel estimation. The paper proposes a scheme to select an effective one from the three methods for frequency and time directions without a detection of fading conditions, which selects the methods based on path metric values. Computer simulation results show that the proposed approach provides the same channel estimation performance as that obtained under an exact detection of fading conditions.

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Hybrid ARQ for Modulo Loss Reduction in Multi-User MIMO THP Systems

Shoya Takebuchi, Hiromichi Tomeba, Takashi Onodera, Minoru Kubota, Fumiaki Maehara, Fumio Takahata

2013 International Symposium on Intelligent Signal Processing and Communication Systems WA2-E-4 2013.10 [Refereed]
会報第42号の発刊によせて

髙畑文雄

テレビ受信向上委員会会報 ( 42 ) 2 - 2 2013.06 [Refereed]
B-5-75 A study on channel estimation for THP MU-MIMO using MMSE receive antenna combining

Takahashi Hirotoshi, Tomeba Hiromichi, Onodera Takashi, Kubota Minoru, Maehara Fumiaki, Takahata Fumio

Proceedings of the IEICE General Conference 2013 ( 1 ) 485 - 485 2013.03 [Refereed]

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B-5-74 An Affect of Sub-band Channel Ordering to Transmission Performance in VP MU-MIMO

Takada Masato, Tomeba Hiromichi, Onodera Takashi, Kubota Minoru, Maehara Fumiaki, Takahata Fumio

Proceedings of the IEICE General Conference 2013 ( 1 ) 484 - 484 2013.03 [Refereed]

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B-5-3 Astudy on ARQ for Mu-MIMO THP systems

Takebuchi S, Tomeba H, Onodera T, Kubota M, Maehara F, Takahata F

Proceedings of the IEICE General Conference 2013 ( 1 ) 413 - 413 2013.03 [Refereed]

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B-3-20 Verification of Computer-Simulated Satellite Propagation Characteristics based on Three-Dimensional Map byField Test Results for GPS Satellites

Sato Shun, Takahata Fumio

Proceedings of the IEICE General Conference 2013 ( 1 ) 329 - 329 2013.03 [Refereed]

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HMMを利用したLDPC復号法

佐野碧, 髙畑文雄

2013年電子情報通信学会総合大会 B-8-14 2013.03 [Refereed]
A study of perturbation vector search for downlink MU-MIMO using Vector Perturbation

TAKADA Masato, TOMEBA Hiromichi, ONODERA Takashi, KUBOTA Minoru, MAEHARA Fumiaki, TAKAHATA Fumio

Technical report of IEICE. RCS 112 ( 443 ) 31 - 36 2013.02 [Refereed]

　View Summary

This paper proposes the computational complexity reduction technique for the downlink(DL) Multi-User Multiple Input Multiple Output(DL MU-MIMO) using Vector Perturbation(VP). By Searching the optimal perturbation vector among an infinite number of perturbation vector candidate, VP MU-MIMO can reduce the required transmission power, resulting in the good frequency efficiency. However, its computational complexity exponentially increases with the number of spatial multiplexing mobile terminals. To reduce the complexity of VP, QRM-VP has been proposed, which is based on QR decomposition and M algorithm. However, its computational complexity remains relatively high. This paper points out that the optimal perturbation vector search of VP is equivalent to maximum-likehood detection for the received signal. From this observation, this paper proposes the computational complexity reduction technique for VP MU-MIMO, and shows its transmission performance and computational complexity by computer simulation.

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On MMSE receive antenna combining for downlink THP MU-MIMO

TAKAHASHI Hirotoshi, TOMEBA Hiromichi, ONODERA Takashi, KUBOTA Minoru, MAEHARA Fumiaki, TAKAHATA Fumio

Technical report of IEICE. RCS 112 ( 443 ) 7 - 12 2013.02 [Refereed]

　View Summary

This paper proposes an MMSE receive antenna combining suitable for THP MU-MIMO, and shows that it can provide a better transmission performance than conventional THP MU-MIMO. In the linear precoding MU-MIMO, an MMSE receive antenna combining has been proposed, which exploits antennas without feeding back channel information to improve the transmission performance. If the conventional MMSE receive antenna combining proposed to LP MU-MIMO is applied to THP MU-MIMO, the transmission performance of THP MU-MIMO significantly degrades due to the base station configuration difference between LP and THP MU-MIMO. In this paper, we propose an MMSE receive antenna combining suitable for THP MU-MIMO and clarifies its performance by computer simulation.

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新年のご挨拶

髙畑文雄

電波技術協会報 ( 290 ) 3 - 3 2013.01
新年のご挨拶

髙畑文雄

電波技術協会報 296 ( 290 ) 3 - 3 2013.01 [Refereed]
巻頭言無線伝送技術の理解に向けての努力

髙畑文雄

NHK技研R&D ( 136 ) 2 - 3 2012.11 [Refereed]
An OFDM Frequency Domain Dual-Mode DFCE Scheme Based on Log Likelihood Ratio

KUMAGAI Yuki, TAKAHATA Fumio

The transactions of the Institute of Electronics, Information and Communication Engineers. B 95 ( 8 ) 967 - 970 2012.08 [Refereed]

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新任のご挨拶

髙畑文雄

電波技術協会報 ( 287 ) 3 - 3 2012.07 [Refereed]
B-5-59 A Dual-mode COFDM Fast Fading Compensation Scheme using Metric Comparison

Suzuki Toru, Takahata Fumio

Proceedings of the IEICE General Conference 2012 ( 1 ) 458 - 458 2012.03 [Refereed]

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3次元地図データを利用した計算機シミュレーションから得られるGPSの測位性能の実証実験による検証

笠原拓朗, 髙畑文雄

2012年電子情報通信学会総合大会 B-3-11 2012.03 [Refereed]
隠れマルコフモデルを利用したLDPC復号法

佐野碧, 髙畑文雄

2012年電子情報通信学会総合大会 B-5-65 2012.03 [Refereed]
対数尤度操作に基づくCOFDMスキャッタードパイロットフェージング補償方式

熊谷裕己, 髙畑文雄

2012年電子情報通信学会総合大会 B-5-58 2012.03 [Refereed]
対数尤度比を利用した双方向判定帰還型OFDM周波数方向補間法

熊谷祐己, 髙畑文雄

2011年電子情報通信学会ソサイエテイ大会 B-5-4 2011.09 [Refereed]
メトリック比較を利用したCOFDM高速フェージング補償方式

鈴木徹, 髙畑文雄

2011年電子情報通信学会ソサイエテイ大会 B-5-5 2011.09 [Refereed]
非線形多重DMRSを用いるTHP MU-MIMO

山岸誠也, 留場宏道, 小野寺毅, 前原文明, 髙畑文雄

2011年電子情報通信学会ソサイエテイ大会 B-5-37 2011.09 [Refereed]
多値数の異なる変調信号を空間多重する格子基底縮小援用THP MU-MIMO

中野宏文, 留場宏道, 小野寺毅, 前原文明, 髙畑文雄

2011年電子情報通信学会ソサイエテイ大会 B-5-38 2011.09 [Refereed]
An Application of Time Division Multiplexing on Multi-User MIMO THP Systems in the Presence of High Mobility Terminals

Y. WANG, M. SHIMIZU, F. MAEHARA, F. TAKAHATA

2011 IEEE Vehicular Technology Conference (VTC2011-Fall) 2011.09 [Refereed]
Bit Metric Derivation Method Using Residual CCI Signals for Adaptive Antenna Array Coupled with Channel Coding

WANG Yunhan, MAEHARA Fumiaki, TAKAHATA Fumio, ONODERA Takashi, URABE Shuuji

The transactions of the Institute of Electronics, Information and Communication Engineers. B 94 ( 8 ) 959 - 969 2011.08 [Refereed]

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タイミングずれを伴う遅延プロファイルで表現される無線伝搬路に関する各種フェージング補償方式の特性評価

鈴木徹, 高畑文雄

2011年電子情報通信学会総合大会 B-5-6 2011.03 [Refereed]
B-5-5 Performance of Frequency Domain Interpolation Schemes on Propagation Paths expressed by Delay Profile asynchronous with Nyquist Sampling Timing

Kumagai Yuki, Takahata Fumio

Proceedings of the IEICE General Conference 2011 ( 1 ) 391 - 391 2011.02 [Refereed]

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An Effect of Application of Sequential Channel Estimation to LDPC Decoding

SUDOU Yu, TAKAHATA Fumio

IEICE technical report. Signal processing 110 ( 440 ) 287 - 292 2011.02 [Refereed]

　View Summary

In the decoding process of LDPC code, an accuracy of LLRs (Log Likelihood Ratio) affects strongly to BER (Bit Error Rate). In fading environments, an error exists necessarily between an actual propagation channel and a channel estimated from the pilot symbol. Since the channel error increases the absolute value of LLRs of error bits, the decoding performance degrades. The paper proposes the LDPC decoding process utilizing sequential channel estimation to suppress the absolute values. The effectiveness of the proposed scheme is quantitatively evaluated by means of computer simulation from the viewpoint of the decoding performance.

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A Dual-mode Channel Estimation Scheme using Log Likelihood Ratio for COFDM Transmission

SUZUKI Koushin, TAKAHATA Fumio

IEICE technical report. Signal processing 110 ( 440 ) 257 - 261 2011.02 [Refereed]

　View Summary

Decision feedback channel estimation (DFCE) is one of the promising channel estimation schemes for OFDM transmission under fast fading channels. The paper proposes a fading compensation scheme to COFDM transmission of packet encoded by LDPC, where pilot symbols are inserted at both ends of each packet and DFCEs are carried out in dual modes from the both ends. The proposed scheme has a feature that, among bits compensated in the dual modes, a reliable bit is selected by comparing values of LLR (Log-Likelihood Ratio) and supplied to the LDPC decoding. Computer simulation results show that the proposed approach provides better BER than the traditional decision feedback channel estimation scheme.

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A Signal Detection Scheme using Log Likelihood Ratio in MIMO-OFDM-SDM System

TAKAHASHI Ryota, TAKAHATA Fumio

IEICE technical report. Signal processing 110 ( 440 ) 251 - 256 2011.02 [Refereed]

　View Summary

A MIMO-OFDM-SDM system, which provides good transmission quality irrespective of various conditions of propagation channels, is proposed. The system carries out to select a demodulated bit before the FEC decoding by comparing values of LLR (Log Likelihood Ratio) for each bit obtained with/without MMSE. Transmission performance of the proposed system is obtained by computer simulation, and its effectiveness is evaluated compared with the performance obtained by conventional systems.

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On Channel Estimation and Compensation in DFTS-OFDM using Scattered Pilot

SATO Akihiko, TAKAHATA Fumio

IEICE technical report. Circuits and systems 110 ( 439 ) 67 - 72 2011.02 [Refereed]

　View Summary

Scattered pilots (SP) would be effective for the estimation and compensation of fast fading propagation paths. This paper discusses an application of SP to DFT Spread OFDM (DFTS-OFDM) transmission. After we derive theoretically a delay profile of the system, based on the discussion of the delay profile, we propose an inter-polation method of the frequency response of propagation paths and an estimation method of noise power. Finally the performance obtained by the proposed methods is quantitatively evaluated by means of computer simulation, and compared with the performance of schemes utilizing conventional methods.

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Overlap-FDEを用いるOFDM伝送への周波数ダイバーシチの適用

小堀哲也, 高畑文雄

IEICE Transactions on Communications J93-B ( 12 ) 1651 - 1659 2010.12 [Refereed]

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The effectiveness of bit metric derivation method using residual CCI power in post-FFT type OFDM adaptive array

Y. Wang, F. Maehara, F. Takahata

Proc. 15th International OFDM Workshop 2010 (InOWo'10) 120 - 124 2010.09 [Refereed]
伝搬路の相関性を考慮したMIMO-OFDM-SDM システムにおける受信機構成

吉原龍彦, 吉田真之, 前原文明, 高畑文雄, 小野寺毅, 卜部周二

電子情報通信学会論文誌B J93-B ( 3 ) 448 - 460 2010.03 [Refereed]
SC-FDE に対する周期スペクトラム伝送の適応制御方式

武藤友佑, 高畑文雄

電子情報通信学会論文誌B J93-B ( 3 ) 461 - 470 2010.03 [Refereed]
各種衛星測位システムの特性について

田淵翔, 高畑文雄

2010年電子情報通信学会総合大会 B-3-21 2010.03 [Refereed]
ターボ符号の尤度操作によるMIMO-OFDM-SDMにおける特性改善

吉田真之, 高畑文雄, 前原文明, 小野寺毅

2010年電子情報通信学会総合大会 B-5-43 2010.03 [Refereed]
OFDMパケット伝送へのスキャッタードパイロットと双方向判定帰還型伝搬路推定法の併用

鈴木光信, 高畑文雄

2010年電子情報通信学会総合大会 B-5-64 2010.03 [Refereed]
周波数ダイバーシチのブランチ数適応制御を適用したOFDM伝送方式

小堀哲也, 高畑文雄

2010年電子情報通信学会総合大会 B-5-66 2010.03 [Refereed]
対数尤度比のフィードバックによる誤り訂正符号化OFDM伝送

須藤勇, 高畑文雄

2010年電子情報通信学会総合大会 B-5-87 2010.03 [Refereed]
位相回転を考慮したSC-FDE判定帰還型伝搬路推定法

熊谷聡一郎, 高畑文雄

2010年電子情報通信学会総合大会 B-5-101 2010.03 [Refereed]
SC-FDEに対する時間領域判定帰還型伝搬路推定法の適用

熊谷聡一郎, 谷口将一, 高畑文雄

2009年電子情報通信学会通信ソサイエテイ大会 B-5-17 2009.09 [Refereed]
無線通信技術における一関心事

高畑文雄

TELECニュース 97 1 - 2 2009.07 [Refereed]
OFDMシステムへのOverlap-FDE適用時のBERフロア抑圧に関する検討

小堀,高畑

電子情報通信学会技術報告 WBS2008-128 ( 473 ) 469 - 474 2009.03 [Refereed]

　View Summary

An overlap-FDE has a capability of eliminating a guard interval (GI) in OFDM transmission. However it is possible in multipath propagation to generate a floor in BER performance irrespective of high E_b/N_0 condition. The paper proposes three types of schemes for suppressing the BER floor, which are ones changing with/without GI, utilizing carrier holes and applying frequency diversity. The performance is evaluated by means of computer simulation, comparing with conventional OFDM transmission with GI.

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伝送路の相関性を考慮したMIMO-SDMシステムの提案

吉原,前原, 高畑, 小野寺

電子情報通信学会技術報告 WBS2008-133 501 - 506 2009.03 [Refereed]
Performance of bit metric derivation method using CCI signals for OFDM adaptive array antenna

Yunhan Wang, Fumiaki Maehara, Fumio Takahata, Takashi Onodera, Shuuji Urabe

2009 15th Asia-Pacific Conference on Communications, APCC 2009 174 - 177 2009 [Refereed]

　View Summary

This paper proposes a bit metric derivation method for OFDM adaptive array in combination with channel coding. In the proposed approach, post-FFT processing is adopted as an OFDM adaptive array architechture and the bit metric required for channel coding is derived considering the effect of the residual CCI signals in the array output of each sub-channel. The transmission performance is evaluated in the presence of severe CCI channels by means of the computer simulations and the effectiveness of the proposed approach is demonstrated compared with the traditional bit metric method. ©2009 IEEE.

DOI
安心・安全な社会の実現に向けた衛星利用の動向

高畑

電子情報通信学会論文誌 J91-B ( 12 ) 1538 - 1546 2008.12 [Refereed]
New Bit Metric Derivation Method for Adaptive Array Antenna with Channel Coding

F. Maehara, F. Takahata

The 11th International Symposium on Wireless Personal Multimedia Communications (WPMC’08) 2008.09 [Refereed]
静止衛星に対する見通し率予測について

田淵, 佐藤, 高畑

電子情報通信学会2008年ソサイエティ大会 B-3-11 2008.09 [Refereed]
準天頂衛星に対する3次元地図データを用いた見通し率予測について

佐藤, 田淵, 高畑

電子情報通信学会2008年ソサイエティ大会 B-3-12 2008.09 [Refereed]
SC-FDEに対する周期スペクトラム伝送の適応制御に関する検討

武藤, 伊藤, 高畑

電子情報通信学会2008年ソサイエティ大会 B-5-29 2008.09 [Refereed]
誤り訂正復号における軟判定尤度操作による2波同一チャネル干渉抑圧法

冠, 前原, 高畑, 小野寺

電子情報通信学会2008年ソサイエティ大会 B-5-30 2008.09 [Refereed]
MIMO-SC-FDEシステムに対する周期スペクトラム伝送の適用効果

伊藤, 武藤, 高畑

電子情報通信学会2008年ソサイエティ大会 B-5-75 2008.09 [Refereed]
誤り訂正復号における尤度操作による干渉抑圧方式の有相関伝搬路MIMO-SDMシステムへの適用

吉原, 吉田, 前原, 高畑

電子情報通信学会2008年ソサイエティ大会 B-8-2 2008.09 [Refereed]
同一チャネル干渉下におけるCOFDMシステム用軟判定ゆう度情報生成法

平、冠, 前原, 高畑

電子情報通信学会論文誌B J91-B ( 5 ) 575 - 584 2008.05 [Refereed]
次世代安心・安全ICTフォーラムにおける検討状況について

高畑

ワイヤレス・テクノロジー・パーク2008 2008.05 [Refereed]
適応フィルタによるガードバンドの外挿処理を施したOFDM用周波数領域伝搬路推定法

池田, 吉田, 平, 前原, 高畑

電子情報通信学会論文誌B J91-B ( 4 ) 450 - 456 2008.04 [Refereed]
次世代安心・安全ICTフォーラムについて

高畑

電子情報通信学会2008年総合大会 BP-1-1 2008.03 [Refereed]
次世代安心・安全ICTフォーラムの取組

高畑

災害・危機管理ICTシンポジウム2008 2008.02 [Refereed]
Simple Series Form Formula of BER Performance for DQPSK/OFDM Signals in Comprehensive Nonlinear Fading Channels

F. Maehara, A. Taira, F. Takahata

2008 IEEE Radio and Wireless Symposium (RWS2008) 37 - 44 2008.01 [Refereed]
A Soft Bit Metric Calculation Method against Co-Channel Interference in COFDM Systems

A. Taira, M. Kammuri, F. Maehara, F. Takahata

10th International Symposium on Wireless Personal Multimedia Communications ( W-3F ) 828 - 832 2007.12 [Refereed]
3次元地図データを用いた衛星電波伝搬特性の一評価法

三隅, 藤原, 高畑

電子情報通信学会2007年ソサイエティ大会 B-3-3 2007.09 [Refereed]
同一チャネル干渉時におけるSC-FDE伝搬路分離推定法に関する一検討

黒坂, 高畑, 小野寺

電子情報通信学会2007年ソサイエティ大会 B-5-50 2007.09 [Refereed]
CDDを用いたSC-FDEに対する周期スペクトラム伝送の適用効果

武藤, 高畑

電子情報通信学会2007年ソサイエティ大会 B-5-53 2007.09 [Refereed]
OFDM伝送時における軟判定ビタビ復号を用いた同一チャネル干渉抑圧効果

冠、平, 前原, 高畑, 小野寺

電子情報通信学会2007年ソサイエティ大会 B-5-64 2007.09 [Refereed]
OFDM伝送時におけるターボ符号を用いた同一チャネル干渉抑圧効果

平、冠, 前原, 高畑

電子情報通信学会2007年ソサイエティ大会 B-5-65 2007.09 [Refereed]
OFDM link adaptation scheme using periodic signals under inter-symbol interference channels

F. Maehara, A. Taira, F. Takahata

Proc. 12th International OFDM Workshop 2007 (InOWo'07) 321 - 325 2007.08 [Refereed]
Periodic spectrum transmission for single-carrier transmission frequency-domain equalization

Fumiaki Maehara, Satoshi Goto, Fumio Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E90B ( 6 ) 1407 - 1414 2007.06 [Refereed]

　View Summary

This paper proposes a frequency diversity scheme using only even-numbered samples for single-carrier transmission with frequency-domain equalization (SC-FDE). In the proposed scheme, a periodical frequency spectrum generated by using only even-numbered samples in the time domain provides the frequency redundancy, which is utilized for frequency diversity. Moreover, in order to avoid the data rate reduction due to the decrease in the samples within one block, the high-level modulation is applied to each sample and the transmitting power of each sample can be doubled for the equivalent power transmission instead. Computer simulation results show that the proposed scheme provides a steeper BER curve than the typical SC-FDE over frequency selective fading channels, while the typical SC-FDE is more favorable than the proposed scheme over flat fading channels. Moreover, the proposed scheme still retains its characteristic even when channel estimation and channel coding are additionally taken into account.

DOI
同一チャネル干渉下における尤度情報生成法に関する検討

平、冠, 前原, 高畑

電子情報通信学会技術報告 RCS2007-21 61 - 66 2007.06 [Refereed]
安心・安全な社会の実現に向けた情報通信技術のあり方に関する調査研究会最終報告書概要

高畑

平成19年度地域衛星通信ネットワーク担当者会議(自治体衛星通信機構) 2007.05 [Refereed]
適応変調OFDM用FDMパイロットによるCIR推定精度評価

中村, 野上, 小野寺, 岡本, 高畑

電子情報通信学会2007総合大会 B-5-76 2007.03 [Refereed]
超低遅延無線IPパケット伝送におけるパケット誤り率の解析的導出法

渡部, 前原, 小西, 王, 北原, 中村, 太田, 高畑

電子情報通信学会2007総合大会 B-5-182 2007.03 [Refereed]
時間選択性フェージングが超低遅延無線IPパケット伝送特性に与える影響

小松, 前原, 小西, 王, 北原, 中村, 太田, 高畑

電子情報通信学会2007総合大会 B-5-183 2007.03 [Refereed]
Iterative decision feedback channel estimation using metrics comparison for burst mode COFDM transmission

Haruhito Yoshida, Fumiaki Maehara, Fumio Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E89B ( 12 ) 3475 - 3478 2006.12 [Refereed]

　View Summary

This letter presents an iterative decision feedback channel estimation scheme for burst mode COFDM transmission. The feature of the proposed scheme is that the channel estimation using metrics comparison is applied to the initial stage of the iterative mechanism, which makes it possible to provide a reliable data stream at the initial stage. Computer simulation results show that the proposed approach provides better BER than the traditional iterative decision feedback channel estimation scheme irrespective of the number of iterations.

DOI
IMT-Advanced を中心とした移動通信システムの国際標準化に関する動向

高畑

島田理化技報(創立60周年記念号) ( 18 ) 3 - 10 2006.12 [Refereed]
Performance of Periodic Spectrum Transmission for Single-Carrier with Frequency-Domain Equalization using Channel Coding

T. Kuriyama, H. Yoshida, A. Taira, F. Maehara, F. Takahata

First International Conference on Communications and Electronics 2006.10 [Refereed]
Frequency-Domain Channel Estimation Scheme using RLS-Based Guard Band Frequency Response Extrapolation for OFDM Systems

Y. Ikeda, H. Yoshida, F. Maehara, F. Takahata

9th International Symposium on Wireless Personal Multimedia Communications (WPMC2006) 2006.09 [Refereed]
Adaptive Forgetting Factor Control Scheme for Decision Feedback Channel Estimation in COFDM Transmission

H. Yoshida, F. Maehara, F. Takahata

11th International OFDM-Workshop (InOWo’06) 2006.08 [Refereed]
デジタル放送を取り巻く技術と経済の動向について

高畑

映像情報メディア学会誌 60 ( 5 ) 662 - 665 2006.05 [Refereed]
Inter-symbol Interference Suppression Sheme using Periodic Signal Waveform for Fixed-rate COFDM Systems

F. Maehara, S. Goto, F. Takahata

2006 IEEE 63rd Vehicular Technology Conference (VTC2006-Spring) 2006.05 [Refereed]
周期スペクトラムを用いた符号化STTD-SC-FDEの特性評価

栗山,吉田, 前原,高畑

2006年電子情報通信学会全国大会 B-5-42 2006.03 [Refereed]
OFDMシステムへのTDD簡易伝搬路予測に基づく時間軸送信電力配分の適用効果に関する検討

神谷,吉田, 前原,高畑

2006年電子情報通信学会全国大会 B-5-91 2006.03 [Refereed]
COFDM伝送における適応忘却係数制御を用いた判定帰還伝搬路推定に関する検討

吉田, 前原,高畑

2006年電子情報通信学会全国大会 B-5-95 2006.03 [Refereed]
RLSアルゴリズムに基づくガードバンド外挿処理を用いたOFDM周波数領域伝搬路推定法に関する一検討

池田,吉田, 前原,高畑

2006年電子情報通信学会全国大会 B-5-96 2006.03 [Refereed]
遅延時間に制限のある無線IP伝送におけるパケット誤り率の近似的導出法

前原,小西,王, 北原, 高畑,後藤

2006年電子情報通信学会全国大会 B-5-169 2006.03 [Refereed]
OFDMシステムへのTDD簡易伝搬路予測に基づく時間軸送信電力配分の適用効果

神谷,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-125 7 - 12 2006.01 [Refereed]
ガードバンドが存在するOFDM伝送を対象としたRLSアルゴリズムに基づく周波数領域伝搬路推定法に関する一検討

池田,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-126 13 - 18 2006.01 [Refereed]
判定帰還伝搬路推定を用いたOFDM伝送における適応忘却係数制御に関する一検討

吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-127 19 - 24 2006.01 [Refereed]
周期スペクトラムを用いたSTTD-SC-FDEへの誤り訂正の適用効果

栗山,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-150 155 - 160 2006.01 [Refereed]
Periodic Spectrum Transmission for Single-carrier Frequency-domain Equalization employing Space-time Transmit Diversity

H. Yoshida, T. Kuriyama, F. Maehara, F. Takahata

Proc. International Symposium on Wireless Pervasive Computing 2006 (ISWPC2006) ( F1-3 ) 2006.01 [Refereed]
Optimal Methods of Space Communications for constructing a Ubiquitous Network Society

F. Takahata

7th International Forum on Advanced Satellite Communications in the Asia-Pacific Region 23 - 34 2005.11 [Refereed]
バーストの両端にパイロットシンボルを配置したCOFDM伝送におけるメトリック比較を用いたフェージング補償法

吉田, 前原,高畑

電子情報通信学会論文誌 J88-B ( 10 ) 2119 - 2122 2005.10 [Refereed]
STTDを用いたSC-FDEへの周期スペクトルの適用効果

栗山,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-87 13 - 18 2005.10 [Refereed]
ガードバンドが存在するOFDM伝送を対象とした時間領域伝搬路推定法に関する一検討

池田,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2005-101 97 - 102 2005.10 [Refereed]
Inter-symbol Interference Suppression Employing Sub-carrier Group Selection for OFDM-TDD Transmit Diversity

F. Maehara, T. Ikenaga, F. Takahata, S. Goto

2nd International Symposium on Wireless Communication Systems 2005 (ISWCS2005) 2005.09 [Refereed]
アドホックDSR通信モジュールの実装と評価

徳間, 久須美, 仲田, 鈴木,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-21-27 2005.09 [Refereed]
リンクレイヤフィードバックを用いたアドホックルーティングプロトコルの実装と評価

升田,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-21-26 2005.09 [Refereed]
移動無線環境下におけるストリーミングデータのフレーム再送方式に関する一検討

一文字, 安藤,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-5-122 2005.09 [Refereed]
STTDを用いたSC-FDEへの周波数ダイバーシチの適用効果

栗山,吉田, 前原,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-5-82 2005.09 [Refereed]
ガードバンドが存在するOFDM伝送を対象とした伝搬路推定法に関する一検討

吉田, 前原,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-5-68 2005.09 [Refereed]
周回衛星通信システムにおける衛星ダイバーシチを用いたソフトハンドオーバ方式の適用効果について

塚本, 鈴木,高畑

2005年電子情報通信学会通信ソサイエテイ大会 B-3-21 2005.09 [Refereed]
An Application of Iterative Channel Estimation to Fading Compensation using Metrics Comparison in Burst Mode COFDM Transmission

H. Yoshida, F. Maehara, F. Takahata

Proc. 2005 Hawaii, IEICE and SITA Joint Conference on Information Theory (HISC 2005) 105 ( 83 ) 49 - 54 2005.05 [Refereed]

　View Summary

This paper presents an application of iterative channel estimation to the fading compensation using metrics comparison in burst mode COFDM transmission. In this scheme, the decision feedback channel estimation using forward error correction (FEC) is adopted and the pilot symbols inserted at both ends realize the forward and backward fading compensation. The feature of this scheme is that the decoded data is chosen by comparing the metrics of the two-way FEC. Moreover, in order to improve the bit error rate (BER) further, an iterative channel estimation technique is also applied to this scheme. This paper mainly focuses on the effectiveness of the iterative channel estimation to this scheme and evaluate it compared with the typical decision feed back channel estimation and compensation.

CiNii
A Dual-mode Decision Feedback Channel Estimation over Fast Fading Channels for COFDM Transmission

H. Yoshida, F. Maehara, F. Takahata

Proc. IASTED International Conference on Networks and Communication Systems (NCS2005) 457 - 461 2005.04 [Refereed]
Scheduling Algorithm based on Sender Buffer Backlog for Real-Time Application in Mobile Packet Networks

H. Koto, M. Fukushima, S. Nomoto, F. Takahata

IEEE Wireless Communications & Networking Conference 2005.03 [Refereed]
バーストの両端にパイロットシンボルを配置したCOFDM伝送におけるメトリック比較を用いたフェージング補償法に関する検討

吉田, 前原,高畑

電子情報通信学会技術報告 WBS2004-194 55 - 59 2005.03 [Refereed]
両端にパイロットシンボルを配置したフレーム構成におけるメトリック比較を用いたOFDM用高速フェージング補償法の一検討

吉田, 前原,高畑

2005年電子情報通信学会総合大会 B-5-37 2005.03 [Refereed]
衛星通信の発展

高畑

URSI電波研連C分科会第19期第5回公開研究会 2005.01 [Refereed]
TDD-OFDM伝送を対象とした送信SC/受信MRCダイバーシチに関する一検討

吉田,高畑

2004年電子情報通信学会通信ソサイエテイ大会 B-5-106 2004.09 [Refereed]
移動体ダウンリンクパケット通信システムにおける動画ストリーミングを考慮したスケジューリング方式に関する検討

小頭,福嶋, 野本,高畑

2004年電子情報通信学会通信ソサイエテイ大会 B-15-16 2004.09 [Refereed]
序論〜映像情報メディア分野における最近の動向〜

高畑

映像情報メディア学会誌 58 ( 8 ) 1056 2004.08 [Refereed]
Ku-band long distance site-diversity (SD) characteristics using new measuring system

T Hatsuda, Y Aoki, H Echigo, F Takahata, Y Maekawa, K Fujisaki

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 52 ( 6 ) 1481 - 1491 2004.06 [Refereed]

　View Summary

This paper deals with the short (10 km) and long distance (300-1400 km) site-diversity (SD) characteristics by using a newly developed measuring system. In the proposed measuring system, six earth stations transmit 14-GHz band QPSK signals, and one measuring earth station receives 12-GHz band signals and processes them to determine SD characteristics. As a result, easy operation and maintenance, low-cost measuring system construction and highly accurate data-have been obtained. By comparing those measured results with the SD joint probability approximation equation in ITU-R Rec.P.618-7, a good agreement can be obtained. Furthermore, the effect of typhoons on SD characteristics were measured.

DOI
Inter-symbol interference suppression scheme using even-numbered sub-carriers for fixed-rate OFDM systems

F Maehara, F Sasamori, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E87B ( 4 ) 866 - 872 2004.04 [Refereed]

　View Summary

This paper proposes an inter-symbol interference (ISI) suppression scheme using only the even-numbered sub-carriers for the fixed-rate OFDM systems with the 2-dimensional modulation. The proposed scheme is based on the principle that the first half of the waveform in the time domain is the same as the second half when an OFDM symbol is composed of only the even-numbered sub-carriers. The feature of the proposed scheme is that, in the case of the maximum multipath delay beyond the duration of the guard interval, the OFDM symbol with only the even-numbered sub-carriers is transmitted in order to generate the extended virtual guard interval and that the high-level modulation with the sub-carrier power enhancement is applied to achieve the constant data rate. In addition, at the receiver, only the second half of the OFDM symbol is used for the FFT processing to avoid the ISI. Moreover, the condition of the maximum multipath delay is notified to the transmitter by using the feedback channel. Numerical results given by computer simulation showed that the proposed scheme provides far better bit error rate (BER) performance than the traditional OFDM transmission using all sub-carriers under the multipath delay beyond the duration of the guard interval.
私と電波電波の奥深さ

高畑

電波受験界 52 ( 3 ) 10 - 11 2004.03 [Refereed]
トップは語る和田紀夫NTT社長に聞く

高畑

映像情報メディア学会誌 58 ( 1 ) 1 - 7 2004.01 [Refereed]
Fast fading compensation schemes for OFDM transmission

H Yoshida, F Maehara, F Sasamori, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 87 ( 4 ) 35 - 44 2004 [Refereed]

　View Summary

A decision feedback compensation scheme that successively updates the channel estimate based on the decision values of the channel estimate (CE) symbols inserted in the frame header and the symbols in the data section is an effective fading compensation scheme for orthogonal frequency-division multiplexing (OFDM). However, when rapid phase fluctuations are produced as the received signal level drops in the frame, errors are propagated in successive symbols, and the accuracy of the fading compensation severely degrades. In this paper, we propose a fading compensation scheme for information symbols that places CE symbols in the last section in addition to those in the header section in one frame, which should lessen the error propagation effect. Specifically, we propose a direction-controlled unidirectional fading compensation scheme that adaptively controls the compensation direction based on the instantaneous signal-to-noise ratio (SNR) estimated from the CE symbols on both ends for each subcarrier and a bidirectional fading compensation scheme that detects drops in the received signal level in a frame and switches the direction of the fading compensation. The results of the performance evaluation showed that the performance was improved by the former scheme in a fast fading environment, and a significant improvement in the transmission performance was possible by applying the latter scheme. (C) 2003 Wiley Periodicals, Inc.

DOI
A compensation method based on recursive processing of Nonlinear distortion for OFDM

H Hosono, T Hosokawa, T Maeda, F Maehara, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 87 ( 7 ) 55 - 65 2004 [Refereed]

　View Summary

OFDM (orthogonal frequency division multiplexing) signal generates a very large signal amplitude. Consequently, distortion due to nonlinearity is produced when the signal is amplified through a nonlinear amplifier, which greatly degrades BER (bit-error rate) performance. As a method of handling this problem, this paper proposes highly accurate compensation processing of nonlinear distortion by constructing a replica of the OFDM signal in the receiver. The proposed method is based on the hard decision result of demodulated received symbols containing nonlinear distortion, and the nonlinear distortion component is recursively estimated and compensated. The performance of the proposed method is evaluated by computer simulation assuming a thermal noise environment, and it is shown that the proposed method is better in both BER and the number of constructed replicas. The performance of the proposed method is also evaluated assuming a fading environment when the method is applied to land mobile communications. The problems of fading compensation when the distortion caused by nonlinear amplification is superposed are pointed out. (C) 2004 Wiley Periodicals, Inc.

DOI
無線TCP性能評価への2状態マルコフ過程を用いたパケット誤りモデルの適用に関する検討

小頭,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2003-213 157 - 162 2003.11 [Refereed]
低軌道周回衛星通信システムNeLSにおけるTCP/IPスループット特性に関する検討

鈴木,高畑

2003年電子情報通信学会通信ソサイエテイ大会 B-3-1 2003.09 [Refereed]
ネットワークシミュレータnsによる無線LANのスループット特性評価

久須美,高畑

2003年電子情報通信学会通信ソサイエテイ大会 B-15-6 2003.09 [Refereed]
移動無線通信におけるLayer2-ARQ適用時のUDP特性評価

安藤, 小頭,高畑

2003年電子情報通信学会通信ソサイエテイ大会 B-15-7 2003.09 [Refereed]
周波数選択性レイリーフェージング環境下におけるMC-CDMA伝送のTCPスループット特性に関する検討

小頭, 笹岡,高畑

2003年電子情報通信学会通信ソサイエテイ大会 B-15-8 2003.09 [Refereed]
Approximate expression of BER performance in DS-CDMA systems over multi-path fading channels

F Sasamori, S Handa, F Maehara, F Takahata, S Oshita

IEICE TRANSACTIONS ON COMMUNICATIONS E86B ( 8 ) 2523 - 2528 2003.08 [Refereed]

　View Summary

The transmission quality in mobile wireless communication systems is affected by not only AWGN but also multi-path fading. Particularly, the Doppler frequency, the delay spread and the Rician factor have a great influence upon the quality over fading channels. This letter proposes the approximate equation for easily calculating the BER in DS-CDMA systems over multi-path fading channels. The validity of the approximate equation is confirmed from the fact that the BER calculated by the equation coincides with that by the computer simulation.
COFDM伝送における両方向伝搬路推定方式に関する一検討

吉田, 前原,高畑

電子情報通信学会技術報告 WBS2003-22 1 - 4 2003.06 [Refereed]
Inter-symbol Interference Suppression Scheme using Even-numbered Sub-carriers for OFDM Systems

F. Maehara, F. Sasamori, F. Takahata

IST Mobile & Wireless Communications Summit 2003 83 - 87 2003.06 [Refereed]
同一チャネル干渉存在下におけるMAP復号の対数尤度の一決定法

鈴木, 前原,高畑

2003年電子情報通信学会総合大会 B-5-12 2003.03 [Refereed]
一部サブキャリヤのみを使用するOFDM伝搬路推定法の一提案

齋藤,吉田, 前原,高畑

2003年電子情報通信学会総合大会 B-5-58 2003.03 [Refereed]
非線形増幅OFDM信号のガウス近似によるBER特性の導出

名越, 山田,高畑

2003年電子情報通信学会総合大会 B-5-67 2003.03 [Refereed]
Performance Evaluation of Carrier Interferometry OFDM with Space Diversity

F. Maehara, F. Takahata

2003年電子情報通信学会総合大会 B-5-96 2003.03 [Refereed]
OFDM/FDDシステムにおけるクローズドループ振幅・位相制御を用いた選択送信ダイバーシチの一構成

栗田, 前原,高畑

2003年電子情報通信学会総合大会 B-5-190 2003.03 [Refereed]
An Effect of Error Modeling Accuracy to TCP Throughput Performance

H. Koto, F. Maehara, F. Takahata

2003年電子情報通信学会総合大会 SB-14-1 2003.03 [Refereed]
OFDM伝送における誤り訂正と周波数ダイバーシチの併用効果に関する基礎的検討

吉田, 前原,高畑

電子情報通信学会技術報告 SST2002-217 199 - 204 2003.03 [Refereed]
Approximate equation of average bit-error rate-in DS-CDMA systems over fading channels

F Sasamori, F Maehara, S Handa, S Oshita, F Takahata

IEEE TRANSACTIONS ON COMMUNICATIONS 51 ( 3 ) 409 - 415 2003.03 [Refereed]

　View Summary

The transmission quality in mobile wireless communications is affected not only by additive white Gaussian noise, but also by multipath fading, which drastically changes the amplitudes and phases of wireless signals. It is one of the key themes in direct-sequence code-division multiple-access systems to evaluate average bit error rate (BER) performances as parameters of the Doppler frequency, the delay profile, the number of simultaneous access users, and so on. This paper proposes the approximate equation for easily calculating the average BER over fading channels (multiray fading models). The performance evaluations are carried out in the two-ray model, the IMT2000 model, and the COST207 model. It is confirmed from the coincidence of approximate results with computer simulation results that the proposed approach is applicable to a variety of parameters.

DOI
トップは語る海老沢勝二NHK会長に聞く

高畑

映像情報メディア学会誌 57 ( 1 ) 1 - 7 2003.01 [Refereed]
同一チャネル干渉存在下におけるMAP復号の対数尤度に関する検討

鈴木, 前原,高畑

電子情報通信学会技術報告 RCS2002-226 113 - 118 2003.01 [Refereed]
OFDM/FDDシステムにおけるクローズドループ振幅・位相制御を用いた選択送信ダイバーシチに関する検討

栗田, 前原,高畑

電子情報通信学会技術報告 RCS2002-260 43 - 48 2003.01 [Refereed]
Linear predictive maximal ratio combining transmitter diversity for OFDM-TDMA/TDD systems

F Maehara, F Sasamori, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E86B ( 1 ) 221 - 229 2003.01 [Refereed]

　View Summary

This paper proposes a 2-dimensional linear propagation prediction (LPP) in maximal ratio combining (MRC) transmitter diversity for orthogonal frequency division multiplexing (OFDM) time division multiple access-time division duplex (TDMA/TDD) systems in order to overcome the degradation of the transmission performance due to the fast fading or the TDD duration. In the proposed scheme, the downlink channel condition of each sub-channel is predicted by interpolating the uplink fading fluctuation with both the amplitude and phase, and the predicted downlink channel condition is used for the weighting factor to employ MRC transmitter diversity. Numerical results obtained by the computer simulation show that the proposed 2-dimensional LPP with the second-order Lagrangeis interpolation predicts the downlink channel condition accurately under the fast fading or the long TDD duration. Moreover, in such a condition, the proposed LPP provides far better performance than the conventional I-dimensional LPP.
OFDM伝送におけるSIR重み付け受信ダイバーシチ

前原,栗田, 笹森,高畑

電子情報通信学会論文誌 J85-B ( 12 ) 2399 - 2403 2002.12 [Refereed]
高速フェージング環境下におけるOFDM伝送を対象としたフェージング補償方式

吉田,前原, 笹森,高畑

電子情報通信学会論文誌 J85-B ( 11 ) 1874 - 1883 2002.11 [Refereed]
A Frame Timing and Carrier Frequency Synchronization Scheme for OFDM Using Frequency-Shifted Signal

M. Konishi, T. Hosokawa, T. Maeda, F. Takahata

Electronics and Communications in Japan,Part 1 85 ( 10 ) 61 - 70 2002.10 [Refereed]
A new method of demodulating digital SSB signals

Y Saito, T Yamasaki, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E85B ( 10 ) 2255 - 2262 2002.10 [Refereed]

　View Summary

This paper presents the transmission performance of a class-IV partial-response signaling SSB system and proposes a method that can improve its power efficiency. A line code that has no dc component has been used in the SSB transmission of digital signals. The type of line code, such as a partial-response signaling, increases the modulation states, and as a result, decreases the power efficiency. To overcome this obstacle, a new demodulation method called "refiltering and combining" is proposed on the assumption of orthogonal phase detection. The demodulated quadrature channel is re-filtered by a Hilbert filter and is combined with the in-phase channel. It is confirmed by computer simulations that the new demodulation method improves the BER performance and a 3 dB improvement of the power efficiency is obtained.
最大比合成を適用したTDD送信ダイバーシチの平均ビット誤り率の理論的導出法

前原,高畑

電子情報通信学会技術報告 SST2002-36 7 - 11 2002.10 [Refereed]
BPSK信号のRZ-SSB伝送に関する基礎的検討

木村,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-26 2002.09 [Refereed]
ディジタルSSB変復調器の基礎的試作と特性評価

鈴木,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-27 2002.09 [Refereed]
周波数領域信号処理によるMC-CDMA伝送特性の取得と評価

吉田, 前原,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-39 2002.09 [Refereed]
MIMOチャネルを対象としたOFDM伝送方式の伝搬路推定法の一構成

斎藤,吉田, 前原,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-64 2002.09 [Refereed]
フェージング環境下におけるTCP性能解析モデルに関する検討

北原,福嶋, 小頭, 野本,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-115 2002.09 [Refereed]
無線ネットワークシミュレータの基礎的開発

仲田,高畑

2002年電子情報通信学会通信ソサイエテイ大会 B-5-126 2002.09 [Refereed]
Implementation of Improved Markov Error Model to Network Simulator and its Accuracy of simulating Fading Environments

H. Koto, T. Kitahara, F. Maehara, F. Takahata

2002年電子情報通信学会通信ソサイエテイ大会 SB-12-3 2002.09 [Refereed]
Theoretical Derivation Method of Bit Error Rate in Maximal Radio Combining TDD Transmitter Diversity

F. Maehara, F. Sasamori, F. Takahata

2002 4th International Workshop on Mobile and Wireless Communications Network 2002.09 [Refereed]
ふぉーかす“映像情報メディア学会誌について”

高畑

映像情報メディア学会誌 56 ( 8 ) 2002.08 [Refereed]
ネットワークシミュレータへのLayer2 ARQの実装によるワイヤレスTCP/IP伝送特性の評価

小頭,北原, 前原,高畑

電子情報通信学会技術報告 RCS2002-28 61 - 66 2002.04 [Refereed]
最尤判定法を適用したOFDM-SDMシステムにおける演算量削減法

前田, 前原,高畑

電子情報通信学会技術報告 RCS2002-34 99 - 104 2002.04 [Refereed]
2波隣接チャネル干渉に起因するBPSK-BER特性の解析的近似導出法

山田,斎藤, 前原,高畑

電子情報通信学会論文誌 J85-B ( 3 ) 417 - 423 2002.03 [Refereed]
Theoretical derivation method of bit error rate in TDMA/TDD transmitter diversity under cochannel interference

F Maehara, F Sasamori, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E85B ( 3 ) 663 - 666 2002.03 [Refereed]

　View Summary

Transmitter diversity is a powerful technique to improve the transmission quality of downlink in microcellular mobile communications systems. Under cochannel interference (CCI) at the base station (BS), the transmitter diversity is not necessarily effective, because the desired-plus-interference signal power used as a criterion of downlink branch selection is not always relative to the downlink propagation condition. This paper proposes the theoretical derivation of bit error rate (BER) performance in the transmitter diversity under CCI occurring at BS, as parameters of average SIR at BS, normalized Doppler frequency, and so on. It is confirmed from the correspondence of theoretical results with simulation results that the proposed theoretical approach is applicable to the CCI environments at BS.
周回衛星通信システムにおけるネットワーク特性に関する一検討

田村, 和田,高畑

2002年電子情報通信学会総合大会 B-3-25 2002.03 [Refereed]
高低緯度地域における衛星ビーム照射の重複を許容する周回衛星のアンテナビーム半径について

和田, 田村,高畑

2002年電子情報通信学会総合大会 B-3-26 2002.03 [Refereed]
隣接チャネル干渉を許容したPSK信号のチャネル配置に関する検討

山田, 斉藤,高畑

2002年電子情報通信学会総合大会 B-3-31 2002.03 [Refereed]
無線TCP伝送における2状態マルコフエラーモデルの適用領域に関する検討

北原,小頭, 前原, 高畑,福嶋, 古屋,野本

2002年電子情報通信学会総合大会 B-5-5 2002.03 [Refereed]
ネットワークシミュレータへのLayer2 ARQの実装と無線TCP/IP伝送特性の評価

小頭,北原, 前原,高畑

2002年電子情報通信学会総合大会 B-5-6 2002.03 [Refereed]
BPSK-SSB方式における周波数選択性フェージング補償に関する一検討

斎藤, 前原,高畑

2002年電子情報通信学会総合大会 B-5-92 2002.03 [Refereed]
瞬時SIRに基づき最尤判定を適用するサブキャリヤを選択するOFDM-SDMシステムの提案

前田, 前原,高畑

2002年電子情報通信学会総合大会 B-5-166 2002.03 [Refereed]
OFDM伝送における耐同一チャネル干渉受信ダイバーシチの一構成

栗田, 前原,高畑

2002年電子情報通信学会総合大会 B-5-176 2002.03 [Refereed]
OFDM-CEシンボルサブキャリヤ数と伝搬路推定精度に関する検討

齋藤,吉田, 前原,高畑

2002年電子情報通信学会総合大会 B-5-189 2002.03 [Refereed]
空間分割多重を適用したOFDM伝送方式における伝搬路推定法の検討

前原,高畑

2002年電子情報通信学会総合大会 B-5-190 2002.03 [Refereed]
OFDM伝送における高速フェージング変動補償の一構成

吉田, 前原,高畑

2002年電子情報通信学会総合大会 B-5-191 2002.03 [Refereed]
適応変調のMC-CDMA/TDD伝送への適用について

鈴木,名越, 前原,高畑

2002年電子情報通信学会総合大会 B-5-201 2002.03 [Refereed]
Approximate Equation of Bit Error Rate in DQPSK/OFDM Systems over Fading Channels

F. Sasamori, H. Umeda, S. Handa, F. Maehara, F. Takahata, S. Ohshita

European Wireless 2002 1 602 - 607 2002.02 [Refereed]

CiNii
OFDM伝送における非線形ひずみの再帰的処理に基づく補償法

細野,細川, 前田, 前原,高畑

電子情報通信学会論文誌 J85-B ( 1 ) 9 - 19 2002.01 [Refereed]
フェージング環境を対象としたBPSK-SSB変調方式に関する基礎的検討

斎藤, 前原,高畑

電子情報通信学会技術報告 RCS2001-191 53 - 59 2002.01 [Refereed]
2波隣接チャネル干渉に起因するQPSK-BER特性の解析的近似導出法

山田,高畑

電子情報通信学会技術報告 RCS2001-192 61 - 68 2002.01 [Refereed]
OFDM伝送における耐同一チャネル干渉受信ダイバーシチに関する一提案

栗田, 前原,高畑

電子情報通信学会技術報告 RCS2001-198 109 - 115 2002.01 [Refereed]
OFDM伝送における高速フェージング変動補償法に関する一提案

吉田, 前原,高畑

電子情報通信学会技術報告 RCS2001-199 117 - 123 2002.01 [Refereed]
衛星ビーム照射領域の重複を許容する周回衛星の配置に関する特性

和田, 田村,高畑

電子情報通信学会技術報告 RCS2001-212 67 - 74 2002.01 [Refereed]
周回衛星通信システムにおける衛星配置とネットワーク特性に関する検討

田村, 和田,高畑

電子情報通信学会技術報告 RCS2001-213 75 - 82 2002.01 [Refereed]
SIR weighting combining diversity for digital mobile communications

F Maehara, F Sasamori, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 85 ( 7 ) 53 - 60 2002 [Refereed]

　View Summary

Diversity reception is a powerful technique to reduce the degradation of transmission quality caused by fading. One of the techniques, postdetection maximal-ratio combiner (MRC), is not necessarily effective under cochannel interference, because received signal strength used as the weighting factor is not relative to the instantaneous signal-to-interference power ratio (SIR). The paper proposes an SIR estimation method using the matched filter and a diversity scheme using the estimated SIR as the weighting factor. The performance is evaluated theoretically and by means of computer simulations. The results show that the proposed SIR estimation method can estimate the accurate instantaneous SIR and that the BER characteristics of the proposed diversity scheme under cochannel interference realize better performances than those of MRC. (C) 2002 Wiley Periodicals, Inc.

DOI
TDMA/TDD送信ダイバーシチにおける希望信号レベルに基づく最大比合成法の効果

前原,高畑

電子情報通信学会論文誌 J84-B ( 11 ) 2062 - 2065 2001.11 [Refereed]
バースト伝送を対象としたSinc関数補間によるOFDM用伝搬路推定法

齋藤,吉田, 前原,高畑

電子情報通信学会技術報告 RCS2001-157 ( 368 ) 39 - 45 2001.10 [Refereed]

　View Summary

We propose a channel estimation scheme for burst mode OFDM transmission. In the proposed scheme, the propagation characteristics are obtained by interpolating the channel condition of the sub-carrier arranged at a constant frequency interval with Sinc function. The performance of the proposed method is obtained by means of the computer simulations. The results demonstrates that the proposed scheme can estimate the propagation characteristics accurately and realize almost the same BER performance as that of the conventional scheme using all sub-carriers under frequency selective fading environment.

CiNii
OFDM伝送における高速フェージング変動補償に関する一検討

吉田, 前原,高畑

電子情報通信学会技術報告 RCS2001-158 47 - 52 2001.10 [Refereed]
MC-CDMA/TDD伝送における適応変調に関する一検討

鈴木, 前原,高畑

電子情報通信学会技術報告 RCS2001-159 53 - 59 2001.10 [Refereed]
New derivation method of BPSK bit error rate performance in cochannel interference

F Maehara, T Saito, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E84B ( 9 ) 2701 - 2704 2001.09 [Refereed]

　View Summary

New method for deriving the bit error rate (BER) of the BPSK signal in the cochannel interference is proposed, which utilizes the eye pattern of the interference signal, and is different from the conventional method based on the conversion of the interference components to thermal noise. The validity of the proposed derivation method is quantitatively evaluated in terms of the BER performance and is confirmed by comparing with the results obtained by the computer simulation.
2波隣接チャネル干渉に起因するQPSK-BER特性の解析的近似導出法

山田,高畑

2001年電子情報通信学会通信ソサイエテイ大会 B-3-28 2001.09 [Refereed]
Linear Predictive Maximal Ratio Combining Transmitter Diversity for OFDM Systems

F. Maehara, F. Takahata

2001年電子情報通信学会通信ソサイエテイ大会 B-5-95 2001.09 [Refereed]
OFDM伝送における伝搬路推定法に関する一検討

齋藤,吉田, 前原,高畑

2001年電子情報通信学会通信ソサイエテイ大会 B-5-100 2001.09 [Refereed]
OFDM伝送におけるフェージング変動補償に関する一検討

吉田, 前原,高畑

2001年電子情報通信学会通信ソサイエテイ大会 B-5-101 2001.09 [Refereed]
Linear Predictive Maximal Radio Combining Transmitter Diversity for Broadband Wireless Communications Systems

F. Maehara, F. Takahata

The Fourth International Symposium on Wireless Personal Multimedia Communications (WPMC’01) P 2B.27 1065 - 1070 2001.09 [Refereed]
技研に期待すること〜放送技術研究委員会を通した外部の目から〜

高畑

技研だより Top Interview ( 25 ) 2001.08 [Refereed]
蓄積転送周回衛星通信システムにおけるデータ呼中継へのダイクストラ法の適用

細野, 和田,高畑

電子情報通信学会論文誌 J84-B ( 8 ) 1433 - 1442 2001.08 [Refereed]
2波隣接チャネル干渉に起因するBPSK-BER特性の解析的導出法

山田,高畑

電子情報通信学会技術報告 SAT2001-35 9 - 14 2001.07 [Refereed]
周回衛星を用いたグローバル衛星通信システムに関する研究開発-マルチメデイアと蓄積転送-

鈴木,高畑

電子情報通信学会論文誌 J84-B ( 6 ) 963 - 972 2001.06 [Refereed]
隣接チャネル干渉に起因するBPSK-BER特性の解析的導出法

山田,高畑

電子情報通信学会技術報告 SAT2001-28 49 - 56 2001.06 [Refereed]
ビーム照射領域の重複を避ける周回衛星の位置決定法

和田,堀,高畑

電子情報通信学会論文誌 J84-B ( 4 ) 741 - 749 2001.04 [Refereed]
GEO/LEO衛星通信回線におけるTCPの性能評価

北原,小川, 前原,高畑

2001年電子情報通信学会総合大会 SB-2-2 2001.03 [Refereed]
BPSK信号のSSB伝送に関する検討

生田,高畑

001年電子情報通信学会総合大会 B-5-177 2001.03 [Refereed]
QPSK信号のSSB伝送に関する検討

生田,高畑

2001年電子情報通信学会総合大会 B-5-176 2001.03 [Refereed]
サブキャリア適応変調を用いたOFDM/TDD伝送方式の検討

前原,高畑

2001年電子情報通信学会総合大会 B-5-100 2001.03 [Refereed]
衛星ビーム照射領域が重複しない周回衛星通信システムにおける最大ビーム半径の導出

和田, 田村,高畑

2001年電子情報通信学会総合大会 B-3-23 2001.03 [Refereed]
隣接チャネル間干渉に起因するQPSK-BER特性の解析的導出法

山田,齋藤, 前原,高畑

2001年電子情報通信学会総合大会 B-3-12 2001.03 [Refereed]
隣接チャネル間干渉帯域のインパルス応答の導出

齋藤,前原, 山田,高畑

2001年電子情報通信学会総合大会 B-3-11 2001.03 [Refereed]
OFDM用非線形歪みの一補償法

細野,細川, 前田,高畑

2001年電子情報通信学会総合大会 B-3-10 2001.03 [Refereed]
OFDM伝送における非線形歪み補償の一構成法

細野,細川, 前田,高畑

電子情報通信学会技術報告 SAT2000-136 87 - 94 2001.02 [Refereed]
A transmitter diversity with desired signal power selection using matched filter

F Maehara, F Sasamori, F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E84B ( 2 ) 255 - 262 2001.02 [Refereed]

　View Summary

The paper proposes a transmitter diversity scheme with a desired signal selection for the mobile communication systems in which the severe cochannel interference (CCI) is assumed to occur at the base station. The feature of the proposed scheme is that the criterion of the downlink branch selection is based on the desired signal power estimated by the correlation between the received signal and the unique word at the matched filter. Moreover, the unique word length control method according to the instantaneous SIR is applied to the proposed scheme, taking account of the uplink transmission efficiency. Computer simulation results show that the proposed scheme provides the better performance than the conventional transmitter diversity in the seven CCI environments, and that the unique word length control method applied to the proposed scheme decreases the unique word length without the degradation of the transmission quality, comparing with the fixed unique word length method.
周波数シフト信号を用いたOFDM用フレームタイミング/キャリヤ周波数同期方式

小西,細川, 前田,高畑

電子情報通信学会論文誌 J84-B ( 1 ) 61 - 70 2001.01 [Refereed]
日本における衛星通信の研究開発

高畑

電子情報通信学会技術報告 SAT2000-73 5 - 10 2000.12 [Refereed]
Research and Development of Satellite Communications in Japan

F. Takahata

2000 Korea-Japan Joint Conference on Satellite Communications Keynote Speech II 13 - 18 2000.12 [Refereed]
Derivation Method of BER Performance in Adjacent Channel Interference and Cochannel Interference of PSK signals

T. Yamada, D. Ikuta, F. Maehara, F. Takahata

The 6-th Asia-Pacific Conference on Communications (APCC 2000) SR11-3 1102 - 1106 2000.10 [Refereed]
可変ユニークワード長制御を適用した最大比合成送信ダイバーシチ

前原,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-5-3 2000.10 [Refereed]
衛星回線へのTCP/IP適用時の伝送誤りに伴うスループットの低下要因について

北原,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-29 2000.10 [Refereed]
周回衛星システムにおける衛星配置とビーム照射の重複に関する検討

和田,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-28 2000.10 [Refereed]
同一チャネルBPSK信号干渉におけるビット誤り率の近似的導出法

前原,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-26 2000.10 [Refereed]
相互干渉を許容するFDMAチャネル割当てに関する検討

齋藤, 山田,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-24 2000.10 [Refereed]
蓄積転送型LEOシステムにおける中継地球局を介したデータ呼の経路選択法について

細野, 和田,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-8 2000.10 [Refereed]
サブキャリヤ振幅制御によるOFDM信号のピーク抑圧方法

細川,細野, 前田,高畑

2000年電子情報通信学会通信ソサイエテイ大会 B-3-1 2000.10 [Refereed]
ディジタル移動通信におけるSIR重み付け合成ダイバーシチ

前原, 笹森,高畑

電子情報通信学会論文誌 J83-B ( 10 ) 1374 - 1380 2000.10 [Refereed]
Theoretical Performance of Bit Error Rate in TDMA/TDD Transmitter Diversity under Cochannel Interference

F. Maehara, F. Sasamori, F. Takahata

Proceedings of ISAP2000 (2000 International Symposium on Antenna and Propergation) 4A3-5 1489 - 1492 2000.08 [Refereed]

CiNii
同一チャネル干渉下におけるBPSK信号のビット誤り率の近似的導出法

前原,高畑

電子情報通信学会技術報告 SAT2000-65 67 - 71 2000.07 [Refereed]
QPSK信号の隣接チャネル間干渉におけるBER特性と干渉成分の関係について

山田, 生田,高畑

電子情報通信学会技術報告 SAT2000-64 59 - 66 2000.07 [Refereed]
誤り訂正符号と捕捉効果に関する検討

生田, 富田,高畑

電子情報通信学会技術報告 SAT2000-63 53 - 58 2000.07 [Refereed]
蓄積転送LEOシステムにおけるデータ呼中継法に関する検討

細野, 和田,高畑

電子情報通信学会技術報告 SAT2000-62 45 - 52 2000.07 [Refereed]
TDMA/TDDディジタル移動通信におけるSIR重み付け送受信ダイバーシチ

前原,高畑

YRP移動体通信産学官交流シンポジウム2000 51 - 52 2000.07 [Refereed]
周波数選択性レイリーフェージング環境下におけるDS-CDMA方式の平均ビット誤り率の近似的導出法

笹森, 前原,高畑

電子情報通信学会論文誌 J83-B ( 7 ) 960 - 969 2000.07 [Refereed]
遅延検波を適用した最大比合成送信ダイバーシチの検討

前原,高畑

電子情報通信学会技術報告 RCS2000-35 41 - 48 2000.06 [Refereed]
TCP/IPの衛星通信回線への適用について

北原, 前原,高畑

電子情報通信学会技術報告 SAT2000-21 25 - 30 2000.06 [Refereed]
周回衛星通信システムにおける衛星初期配置の最適化に関する一検討

和田,高畑

電子情報通信学会技術報告 SAT2000-20 19 - 24 2000.06 [Refereed]
21世紀の移動通信とデジタル放送を担う「ワイヤレス・コミュニケーション」

高畑

宮崎日日新聞 14面 2000.04 [Refereed]
平均ビット誤り率の近似式を用いたフェージング環境下におけるDS-CDMA方式の特性評価

笹森,高畑

2000年電子情報通信学会総合大会 B-3-47 2000.03 [Refereed]
4相PSK信号の相互干渉によるビット誤り率の劣化に関する検討

生田,山田, 齋藤, 富田,高畑

2000年電子情報通信学会総合大会 B-3-45 2000.03 [Refereed]
隣接チャネルからの干渉電力の導出式

齋藤,山田, 小池,高畑

2000年電子情報通信学会総合大会 B-3-44 2000.03 [Refereed]
マッチドフィルタを用いた最大比合成送信ダイバーシチの検討

前原,高畑

2000年電子情報通信学会総合大会 B-3-43 2000.03 [Refereed]
符号長が異なる拡散符号を用いるスペクトル拡散通信における相互相関特性

小林, 笹森,高畑

2000年電子情報通信学会総合大会 B-3-26 2000.03 [Refereed]
周波数シフト・パイロット信号を用いたOFDM用フレーム同期方式の一構成

小西,細川, 前田,高畑

2000年電子情報通信学会総合大会 B-3-25 2000.03 [Refereed]
OFDM伝送におけるピーク電力低減の一構成法

細川,細野, 小西, 前田,高畑

2000年電子情報通信学会総合大会 B-3-24 2000.03 [Refereed]
蓄積転送型LEOシステムにおける中継地球局配置によるデータ転送所要時間の低減効果について

細野,堀,和田, 小室,高畑

2000年電子情報通信学会総合大会 B-3-10 2000.03 [Refereed]
衛星ビームが重複しない周回衛星の初期配置の導出法

堀,和田,高畑

2000年電子情報通信学会総合大会 B-3-5 2000.03 [Refereed]
NHK放送技術研究所への期待—間近に迫ったBSデジタル放送開始に関連して—

高畑

NHK技研 R&D 60 2 - 3 2000.03 [Refereed]
VSATによる制御局逐次推移型網状遠隔講義システム

鈴木,若林, 江口,武藤, 島田,高畑

JDLA会誌 2 16 - 20 2000.03 [Refereed]

CiNii
蓄積転送型周回衛星通信システムにおける中継地球局の導入の検討とその効果について

細野,堀,和田, 小室,高畑

電子情報通信学会技術報告 SAT99-161 125 - 132 2000.02 [Refereed]
同一チャネル干渉存在下におけるTDMA/TDD送信ダイバーシチのビット誤り率理論特性

前原,高畑

電子情報通信学会技術報告 SAT99-146 15 - 22 2000.02 [Refereed]
PSK信号の相互干渉によるビット誤り率劣化に関する検討

生田,山田, 齋藤, 富田,高畑

電子情報通信学会技術報告 SAT99-145 9 - 14 2000.02 [Refereed]
周波数シフト・パイロット信号を用いたOFDM用フレームタイミング/キャリヤ周波数同期方式の一構成

小西,細川, 前田,高畑

電子情報通信学会技術報告 SAT99-144 1 - 8 2000.02 [Refereed]
ユニークワード長可変型希望波レベル選択送信ダイバーシチの検討

前原,高畑

電子情報通信学会技術報告 SAT99-110 17 - 24 2000.01 [Refereed]
An adaptive equalizer for multiray model in high-speed digital land mobile radio communications

T Ogami, H Sakaida, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS 83 ( 1 ) 44 - 51 2000 [Refereed]

　View Summary

An effective method of signal processing related to adaptive equalization and frame synchronization is proposed, which provides good characteristics for frequency-selective fading due to multipath propagation represented by the multiray model in high-speed digital land mobile communications. This can be realized by adding two types of signal processing to the decision feedback adaptive equalizer based on dual-mode equalization combined with frame synchronization that establishes frame timing from the arriving wave with the strongest correlation with the equalization training sequence. The principle of the proposed signal processing is based on the formation of a data sequence synchronized hypothetically with the preceding and final delayed waves by means of the time shift and on the selection of the best adaptive equalization result. The bit error rate characteristics obtained by the proposed signal processing method are presented under the condition that 16 QAM is used as the modulation scheme and frequency-selective fading is characterized by the 3- through g-ray models delayed at a symbol period interval with D/U = 0 dB, and they are quantitatively evaluated in terms of the frame timing, E-b/N-0, and the amount of shift. (C) 1999 Scripta Technica, Electron Comm Jpn Pt 2, 83(1): 44-51, 2000.
Experimental and theoretical analysis of adjacent channel interference characteristics caused by two digital PSK signals

T Yamada, K Ebata, T Nakanishi, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 83 ( 7 ) 92 - 102 2000 [Refereed]

　View Summary

Adjacent channel interference characteristics due to two PSK signals are discussed based on experimental and theoretical analysis. Experiments were conducted in-house and by using a Ku-band satellite. The experimental approach indicates that the interference characteristics (bit error rate) depend on the ratio of interference to desired signal power for the weak interference, irrespective of different interference conditions. The theoretical approach proposes the estimation of interference characteristics based on the amplitude probability density function of interference signal components. It is found from quantitative evaluation that although the conventional method, which treats interference as thermal noise, estimates the interference characteristics well only for the weak interference, the proposed method estimates the interference characteristics well for both weak and strong interference. Finally, the required increase of the signal power in compensation for the degradation of the bit error rate and achievement of the objective bit error rate is discussed. (C) 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(7): 92-102, 2000.
New derivation methods of BER performance in channel interference of PSK signals

F Maehara, T Saito, F Takahata

2000 IEEE INTERNATIONAL CONFERENCE ON PERSONAL WIRELESS COMMUNICATIONS 123 - 127 2000 [Refereed]

　View Summary

New methods for deriving the bit error rate (BER) in the cochannel interference and the adjacent channel interference am proposed, which utilize the eye pattern of the interference signal and the probability density function of components in interference signals, respectively, and are different from the conventional method based on the conversion of the interference components to thermal noise. These methods are quantitatively evaluated and confirmed as the effective approach in terms of BER performance by the comparison between the results calculated by these methods and the results obtained by the experiment and computer simulation.
Theoretical and Approximate Derivation of Bit Error Rate in DS-CDMA Systems under Rician Fading Environments

F. Sasamori, F. Takahata

IEICE Transactions on Communications E82-A ( 12 ) 2660 - 2668 1999.12 [Refereed]
マッチドフィルタを用いた希望波選択送信ダイバーシチの検討

前原,高畑

電子情報通信学会技術報告 SAT99-104 17 - 23 1999.11 [Refereed]
マッチドフィルタを用いたSIR重み付け合成ダイバーシチの検討

前原,高畑

電子情報通信学会技術報告 SAT99-100 61 - 66 1999.10 [Refereed]
周回衛星からのビーム照射が重複する初期位相範囲の算出法

堀,細野,高畑

1999年電子情報通信学会通信ソサイエテイ大会 B-3-22 1999.09 [Refereed]
周回衛星通信システムにおける衛星高度と地球局仰角およびドップラーシフトの関係

細野,堀,高畑

1999年電子情報通信学会通信ソサイエテイ大会 B-3-21 1999.09 [Refereed]
周波数選択性フェージング環境下におけるDS-CDMA方式の平均ビット誤り率近似式の評価

笹森,高畑

1999年電子情報通信学会通信ソサイエテイ大会 B-3-10 1999.09 [Refereed]
OFDM用キャリア周波数推定方式における周波数推定精度

小西,高畑

1999年電子情報通信学会通信ソサイエテイ大会 B-3-8 1999.09 [Refereed]
Approximate Derivation of Average Bit Error Rate in DS-CDMA Systems under Frequency Selective Fading

F. Sasamori, F. Takahata

International Conference on Computer Communication 1999 00015-1/7-7/7 1999.09 [Refereed]
OFDM用キャリヤ周波数初期捕捉方式

青木,小西, 笹森,高畑

電子情報通信学会論文誌 J82-B ( 9 ) 1709 - 1721 1999.09 [Refereed]
Theoretical and Experimental Consideration for 14/11 GHz Band Signal Attenuation by Rain and Snow Clouds

T. Hatsuda, R. Mitsuhashi, Y. Aoki, F. Takahata

U.R.S.I. FP.24 378 1999.08 [Refereed]
無線LANの移動通信への適用に関する実験的検討

尾曲, 井村,高畑

電子情報通信学会技術報告 SAT99-79 35 - 42 1999.07 [Refereed]
衛星通信回線におけるTCPの性能評価に関する実験的検討

小川, 井村,高畑

電子情報通信学会技術報告 SAT99-77 23 - 28 1999.07 [Refereed]

CiNii
無線パケットOFDM用キャリア周波数推定方式に関する検討

小西, 細川,高畑

電子情報通信学会技術報告 SAT99-75 9 - 16 1999.07 [Refereed]
仲上—ライスフェージング(周波数選択性)環境下におけるDS-CDMA方式の平均ビット誤り率の近似的導出法

笹森,高畑

電子情報通信学会技術報告 SAT99-74 1 - 8 1999.07 [Refereed]
周回衛星通信システムにおける衛星配置と通信特性の関係

細野,堀,高畑

電子情報通信学会技術報告 SAT99-64 27 - 33 1999.07 [Refereed]
早慶合同授業「情報通信2000」

中川,高畑

大学時報 48 ( 267 ) 70 - 75 1999.07 [Refereed]
スペースコラボレーションシステムを利用した早慶合同授業について

高畑,中川

平成11年度情報教育問題フォーラム F 33 - 36 1999.06 [Refereed]
衛星を利用した通信・放送システムの動向と将来展望

高畑

電子情報通信学会技術報告 SANE99-30 71 - 78 1999.06 [Refereed]
移動体通信技術(CDMA,OFDM,干渉,LEO)に関する研究

高畑

移動体通信産学官交流シンポジウム 14A-2 1999.06 [Refereed]
マルチメディア放送を中心とした最近の衛星通信の流れ

高畑

1999年電子情報通信学会総合大会 TB-1-1 1999.03 [Refereed]
1チャネル多数参加型VSAT遠隔会議システムの基礎実験

山本,長原, 上岡, 青木, 鈴木, 若林,武藤, 島田,高畑

1999年電子情報通信学会総合大会 B-3-35 1999.03 [Refereed]
n波レイリーフェージング環境下におけるDS-CDMA方式の平均ビット誤り率の近似的導出法

笹森,高畑

1999年電子情報通信学会総合大会 B-3-25 1999.03 [Refereed]
無変調波干渉に起因するPSK信号の劣化に関する実験結果について

生田, 中西,高畑

1999年電子情報通信学会総合大会 B-3-23 1999.03 [Refereed]
PSK信号における隣接チャネル間干渉特性の実験的解析

中西, 生田,高畑

1999年電子情報通信学会総合大会 B-3-22 1999.03 [Refereed]
OFDMシステムにおける周波数オフセットがビット誤り率へ与える影響

青木,小西, 細川,高畑

1999年電子情報通信学会総合大会 B-3-21 1999.03 [Refereed]
新測定法による長距離サイト・ダイバーシティ特性の測定結果と理論値との比較

初田,三橋, 青木, 越後,高畑, 前川,藤崎

1999年電子情報通信学会総合大会 B-3-19 1999.03 [Refereed]
2層構成の周回衛星通信システムに関する基礎的検討

土田,堀,高畑

1999年電子情報通信学会総合大会 B-3-3 1999.03 [Refereed]
2層構成の周回衛星通信システムに関する基礎的検討

土田,堀, 田口,高畑

電子情報通信学会技術報告 SAT98-105 75 - 80 1999.02 [Refereed]
低軌道周回衛星における初期位相の設定

山際,堀, 細野,高畑

電子情報通信学会技術報告 SAT98-104 67 - 73 1999.02 [Refereed]
衛星通信における捕捉可能条件と適用システムの一構成

上岡, 青木,高畑

電子情報通信学会技術報告 SAT98-103 59 - 65 1999.02 [Refereed]
PSK信号3波による相互干渉特性の実験的解析

中西, 生田,高畑

電子情報通信学会技術報告 SAT98-98 21 - 27 1999.02 [Refereed]
直接拡散スプレッドアロハ通信用キャリア再生方式に関する検討

吉村, 平本,高畑

電子情報通信学会技術報告 SAT98-97 13 - 20 1999.02 [Refereed]
DS-CDMA方式の周波数選択性フェージング環境下における平均ビット誤り率の近似的導出法

笹森,高畑

電子情報通信学会技術報告 SAT98-96 7 - 12 1999.02 [Refereed]
OFDMシステムの周波数オフセット存在下におけるビット誤り率の理論的導出法

青木,小西, 細川,高畑

電子情報通信学会技術報告 SAT98-95 1 - 6 1999.02 [Refereed]
仲上-ライスフェージングとレイリーフェージングが混在する環境下におけるDS-CDMA方式の平均ビット誤り率の導出法

笹森,高畑

電子情報通信学会技術報告 SAT98-99 47 - 53 1999.01 [Refereed]
Long distance site-diversity (SD) characteristics by using new measuring system

T. Hatsuda, R. Mitsuhashi, Y. Aoki, H. Echigo, F. Takahata, Y. Maekawa, K. Fujisaki

IEEE Antennas and Propagation Society International Symposium: Wireless Technologies and Information Networks, APS 1999 - Held in conjunction with USNC/URSI National Radio Science Meeting 1 408 - 411 1999 [Refereed]

　View Summary

This paper deals with the short and long distance (10-1400km) site-diversity (SD) characteristics by using newly developed measuring system. In proposed measuring method, six earth-stations transmit QPSK signals and one measuring earth-station receive signals and process for site-diversity characteristics. As a result, easy operation and maintenance, low cost measuring system construction and high accuracy data can be obtained. By comparing those measured results with the site-diversity joint probability approximation equation in CCIR Rep. S64-4, relatively good agreement can be conformed.

DOI
エンサイクロペデイア電子情報通信ハンドブック

高畑

電子情報通信学会 956 - 962 1998.11 [Refereed]
VSATによる制御局逐次推移型遠隔会議システムの実験

鈴木,若林, 江口, 阿部,武藤, 島田,高畑

都立航空高専平成9年度研究紀要 34 25 - 29 1998.11 [Refereed]
DS-CDMA方式の仲上-ライスフェージング環境下における平均ビット誤り率の近似的導出法

笹森,高畑

電子情報通信学会技術報告 SAT98-44 15 - 20 1998.10 [Refereed]
OFDM用フレーム同期方式の提案

小西, 青木,高畑

電子情報通信学会技術報告 SAT98-43 9 - 14 1998.10 [Refereed]
蓄積転送型低軌道周回衛星通信ネットワークにおける軌道配置と回線接続特性

山際, 水口,高畑

1998年電子情報通信学会通信ソサイエティ大会 SB-3-15 1998.09 [Refereed]
低軌道周回衛星リアルタイム通信システムにおける衛星配置と呼損特性

土田, 尾形,高畑

1998年電子情報通信学会通信ソサイエティ大会 SB-3-14 1998.09 [Refereed]
OFDMシステムにおけるフレーム同期方式の一構成

青木, 小西,高畑

1998年電子情報通信学会通信ソサイエティ大会 B-5-177 1998.09 [Refereed]
OFDM用キャリア周波数初期捕捉の一構成法

小西, 青木,高畑

1998年電子情報通信学会通信ソサイエティ大会 B-5-176 1998.09 [Refereed]
レイリーフェージング環境下におけるDS-CDMA方式の平均ビット誤り率の近似的導出法

笹森,高畑

1998年電子情報通信学会通信ソサイエティ大会 B-3-6 1998.09 [Refereed]
直接拡散スプレッドアロハ通信システムにおける伝送効率の等価パルスを用いた近似的導出法

堀,笹森,高畑

1998年電子情報通信学会通信ソサイエティ大会 B-3-5 1998.09 [Refereed]
無線LANの屋外使用に関する実験的検討

井村,高畑

電子情報通信学会技術報告 SAT98-29 1 - 6 1998.07 [Refereed]
レイリーフェージング環境下におけるDS-CDMA方式を対象としたビット誤り率特性の理論的導出法

笹森, 山根,高畑

電子情報通信学会技術報告 SAT98-7 1 - 6 1998.06 [Refereed]
ディジタルPSK信号2波による隣接チャネル間干渉特性の実験的/理論的解析

山田,江幡, 中西,高畑

電子情報通信学会論文誌 J81-B-II ( 5 ) 399 - 408 1998.05 [Refereed]
我が国における衛星通信実験の現状と展望

高畑, 鈴木,水野

電子情報通信学会誌 J81-B-II ( 5 ) 356 - 364 1998.05 [Refereed]
1地球局受信・処理電波伝搬特性測定法を用いた14/12 GHz帯伝搬特性例

初田,西浦, 高玉, 長谷川, 三橋,青木, 越後,高畑

北海道工業大学研究紀要 26 155 - 162 1998.03 [Refereed]

CiNii
M系列を用いたOFDM用周波数オフセット初期捕捉の一構成法

小西, 青木,高畑

1998年電子情報通信学会総合大会 B-5-242 1998.03 [Refereed]
低軌道周回衛星通信システムにおける軌道傾斜角と人口分布で重みづけられた衛星待機時間の関係

山際, 水口,高畑

1998年電子情報通信学会総合大会 B-3-30 1998.03 [Refereed]
スプレッドアロハ通信用マッチドフィルタ適用キャリア再生方式のビット誤り率特性

笹森,高畑

1998年電子情報通信学会総合大会 B-3-6 1998.03 [Refereed]
OFDM用キャリア引き込み方式の一構成

青木, 小西,高畑

電子情報通信学会技術報告 SAT97-126 9 - 16 1998.02 [Refereed]
ディジタルPSK信号の隣接チャネル間干渉に関する検討

江幡,中西, 山田,高畑

電子情報通信学会技術報告 SAT97-125 1 - 8 1998.02 [Refereed]
Satellite Internet in Japan

F. Takahata

4th International Workshop on Satellite Communications in the Global Information Infrastructure 1998.02 [Refereed]
Approximation method for deriving transmission efficiency in direct-sequence spread ALOHA communications system using a unified spread code

T Kikuta, F Sasamori, F Takahata

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E80A ( 12 ) 2500 - 2508 1997.12 [Refereed]

　View Summary

Considering that the application of the direct-sequence slotted spread ALOHA communications system to access/control channel is effective in communications systems with traffic channels operating at CDMA made, the spread ALOHA communications system is discussed in terms of the system configuration and transmission efficiency. The transmission efficiency of the spread ALOHA communications system using a unified spread code is derived by means of two methods. One is based on the simulation of demodulation algorithm, and the other is based on the approximation by modeling. It becomes obvious front quantitative evaluation in terms of the probability of packet success and the throughput performance that the approximated results coincide with the simulated results, and that the modeling is very effective to estimate the transmission efficiency of the spread ALOHA communications system.
VSATによる制御局逐次推移型遠隔会議システム

鈴木,若林, 武藤, 島田,江口, 阿部,高畑

電子情報通信学会技術報告 SAT97-78 31 - 35 1997.11 [Refereed]
スプレッドアロハ通信用キャリア再生方式の一構成法

笹森,高畑

電子情報通信学会技術報告 SAT97-75 9 - 15 1997.11 [Refereed]
陸上移動体無線通信における位相変動の周波数依存性に関する実験結果

上岡,高畑

1997年電子情報通信学会通信ソサイエティ大会 B-5-65 1997.09 [Refereed]
VSATにおける送受信電力測定

鈴木,若林, 島田,高畑

1997年電子情報通信学会通信ソサイエティ大会 B-3-13 1997.09 [Refereed]
同一の拡散符号を用いた直接拡散スプレッドアロハ方式と従来のアロハ方式におけるスループット特性の比較検討

笹森, 菊田,高畑

1997年電子情報通信学会通信ソサイエティ大会 B-3-9 1997.09 [Refereed]
単一拡散符号を用いる直接拡散スプレッドアロハ方式における伝送特性のモデル化について

菊田, 笹森,高畑

1997年電子情報通信学会通信ソサイエティ大会 B-3-8 1997.09 [Refereed]
3波のPSK信号による相互干渉特性の実験結果について

江幡,中西, 山田,高畑

1997年電子情報通信学会通信ソサイエティ大会 B-3-3 1997.09 [Refereed]
ディジタル衛星通信における大学間高度共同利用網構築の立場から

高畑

1997年教育工学関連学協会連合第5回全国大会 1997.09 [Refereed]
直接スペクトル拡散通信における平均ビット誤り率の一導出法

臼田, 菊田,高畑

電子情報通信学会論文誌 J80-B-II ( 8 ) 700 - 706 1997.08 [Refereed]
単一の拡散符号を用いたスプレッド・アロハ通信用復調方式の構成と特性

菊田,高畑

電子情報通信学会論文誌 J80-B-II ( 8 ) 684 - 691 1997.08 [Refereed]
3種類のアロハ通信方式(スプレッド,ピュア,スロッテド)におけるスループット特性の比較検討

笹森, 菊田,高畑

電子情報通信学会技術報告 SAT97-44 81 - 88 1997.07 [Refereed]
高速ディジタル移動無線における多波モデル用適応等化器の一構成

大神, 境田,高畑

電子情報通信学会論文誌 J80-B-II ( 7 ) 558 - 564 1997.07 [Refereed]
低軌道周回衛星通信システムにおける衛星間中継機能に関する基礎的検討

土田, 山田,高畑

電子情報通信学会技術報告 SAT97-29 23 - 30 1997.06 [Refereed]
相互干渉に起因するディジタルPSK信号の劣化に関する検討

中西,江幡, 山田,高畑

電子情報通信学会技術報告 SAT97-28 15 - 22 1997.06 [Refereed]
大学間共同衛星通信実験

高畑, 小野里, 嶋本,初田, 三橋, 青木, 棚橋, 村井, 佐藤(亨, 木村, 藤崎,大迫, 立居場, 都築, 田崎,岡, 藤原, 越後,康, 大沼

電子情報通信学会誌 80 ( 5 ) 435 - 456 1997.05 [Refereed]

CiNii
ディジタルPSK信号相互干渉特性の理論的導出

中西,小林, 臼田, 菊田,高畑

1997年電子情報通信学会総合大会 SB-3-4 1997.03 [Refereed]
ディジタルPSK信号の相互干渉のモデル化について

小林,中西, 江幡, 菊田,高畑

1997年電子情報通信学会総合大会 SB-3-3 1997.03 [Refereed]
OFDM復調器における周波数オフセット補償の一構成

青木, 菊田,高畑

1997年電子情報通信学会総合大会 B-8-2 1997.03 [Refereed]
蓄積転送型低軌道周回衛星通信システムにおける回線接続特性に関する検討

水口, 山田,高畑

1997年電子情報通信学会総合大会 B-3-58 1997.03 [Refereed]
Kuバンド受信地球局におけるトータルリンク劣化量差をダウンリンク劣化量差とみなす際の誤差について

森,菊田,高畑

1997年電子情報通信学会総合大会 B-3-55 1997.03 [Refereed]
スター型衛星通信ネットワークへの捕捉効果の適用と特性

小林,坊野, 高畑,若林, 江口,阿部, 鈴木,島田

1997年電子情報通信学会総合大会 B-3-54 1997.03 [Refereed]
VSATによる制御局逐次推移型遠隔会議システムの基礎実験

鈴木,江口, 阿部, 若林,島田, 小林,高畑

1997年電子情報通信学会総合大会 B-3-47 1997.03 [Refereed]
拡散符号をランダムに割り当てる直接スペクトル拡散通信における平均ビット誤り率特性の導出

臼田, 菊田,高畑

1997年電子情報通信学会総合大会 B-3-40 1997.03 [Refereed]
スペクトル拡散パケット通信用低E<SUB>b</SUB>/N<SUB>0</SUB>シンボルタイミング検出の一構成法

山田,高畑

1997年電子情報通信学会総合大会 B-3-39 1997.03 [Refereed]
ディジタル衛星通信に関する大学間共同実験・研究の活動状況

高畑

1997年電子情報通信学会総合大会 1997.03 [Refereed]
Key aspects and technologies of satellite communications toward multimedia era

F Takahata

IEICE TRANSACTIONS ON COMMUNICATIONS E80B ( 1 ) 3 - 7 1997.01 [Refereed]

　View Summary

Key aspects and technologies of future satellite communications are discussed toward multimedia era. Onboard processing called the switchboard in the sky and networking taking full advantage of features peculiar to satellite communications are pointed out as essential technologies to overcome a variety of big challenges for realizing future satellite communications. Several experimental and commercial systems are introduced as the first step toward multimedia era.
変復調シミュレーションをベースとした、同一の拡散符号を用いた直接拡散スプレッドアロハ通信方式のスループット特性について

菊田,高畑

電子情報通信学会技術報告 SAT96-128 87 - 92 1997.01 [Refereed]
蓄積転送型低軌道周回衛星通信システムにおける衛星配置について

水口, 山田,高畑

電子情報通信学会技術報告 SAT96-126 71 - 78 1997.01 [Refereed]
Application of direct-sequence spread ALOHA communications system using a unified spread code to random access channel

T Kikuta, F Sasamori, F Takahata

ICICS - PROCEEDINGS OF 1997 INTERNATIONAL CONFERENCE ON INFORMATION, COMMUNICATIONS AND SIGNAL PROCESSING, VOLS 1-3 1060 - 1064 1997 [Refereed]

　View Summary

Considering that the application of the direct-sequence slotted spread ALOHA communications system to the access/control channel is effective in communications systems with traffic channels operating at CDMA mode, the spread ALOHA communications system is discussed in terms of the system configuration and throughput performance. The throughput performance of the spread ALOHA communications system using a unified spread code is derived by means of two methods. One is based on the simulation of demodulation algorithm, and the other is based on the approximation by simple modeling. The modeling consists of two main conditions depending on the collision of packet signals. It becomes obvious from quantitative evaluation that the approximated results coincide with the simulated results, and that the modeling is very effective to evaluate the throughput performance of the spread ALOHA communications system.
北海道統合通信網の構築のための短・長距離局間のSD特性の検討と台風通過時におけるSD特性への影響

奥野,成田, 西浦, 三橋, 青木, 高畑, 越後,前川, 藤崎,初田

電子情報通信学会技術報告 SAT96-85 29 - 34 1996.11 [Refereed]
スペクトル拡散パケット通信におけるコード整合を利用したパケット検出法について

山田,高畑

電子情報通信学会技術報告 SAT96-83 15 - 20 1996.11 [Refereed]
Kuバンド衛星通信システムにおける電波伝搬特性の取得方法に関する検討

森,菊田,高畑

電子情報通信学会技術報告 SAT96-82 7 - 14 1996.11 [Refereed]
4相位相変調信号とキャリア信号における降雨減衰特性の差についての考察

初田,井上, 奥野, 伊藤,小島, 三橋,高畑

平成8年度電気関係学会北海道支部連合大会 160 1996.10 [Refereed]
JCSAT衛星を利用した異偏波降雨減衰量の測定結果

初田,合田, 奥野, 塩浦, 奈良, 長瀬, 小上,小島, 三橋,高畑

平成8年度電気関係学会北海道支部連合大会 159 1996.10 [Refereed]
台風通過時における長距離SD特性の測定結果

初田,塩浦, 奥野, 合田, 奈良, 小島, 小上, 長瀬,三橋, 越後,高畑

平成8年度電気関係学会北海道支部連合大会 158 1996.10 [Refereed]
北海道統合通信網の構築のための短・長距離局間SD特性の測定

奥野,奈良, 塩浦, 合田, 三橋, 青木,越後, 高畑,初田

平成8年度電気関係学会北海道支部連合大会 155 1996.10 [Refereed]
衛星通信の新たな模索と挑戦

高畑

サテライトセッション'96 1996.10 [Refereed]
蓄積転送型低軌道周回衛星から構成される衛星通信システムにおける軌道配置に関する基礎的検討

水口, 山田,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-242 1996.09 [Refereed]
機能の異なる地球局が混在するスター型衛星通信ネットワークへの捕捉効果の適用

小林, 高津,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-238 1996.09 [Refereed]
Kuバンド衛星通信におけるディジタルPSK信号の相互干渉特性

小林,江幡, 菊田,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-235 1996.09 [Refereed]
Kuバンド衛星通信における降雨時雑音電力レベル変動の観測結果について

森,菊田,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-234 1996.09 [Refereed]
直接スペクトル拡散通信における帯域制限時ビット誤り率特性の理論的導出

臼田, 菊田,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-217 1996.09 [Refereed]
同一および異なる両拡散符号に適用可能な直接拡散スプレッド・アロハ通信用復調方式について

松本, 菊田,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-216 1996.09 [Refereed]
スペクトル拡散パケット通信におけるパケット検出の一構成法

山田, 高木,高畑

1996年電子情報通信学会通信ソサイエティ大会 B-215 1996.09 [Refereed]
超高速スペクトラム・アナライザを用いた多重波伝搬特性測定装置

田村,高畑, 村田,中澤

1996年電子情報通信学会通信ソサイエティ大会 B-15 1996.09 [Refereed]
16値QAM変調方式を適用した広帯域陸上移動通信用復調器

境田, 前原,高畑

電子情報通信学会論文誌 J79-B-II ( 8 ) 431 - 440 1996.08 [Refereed]
Long Distance Site Diversity Characteristics and Effects by Typhoon Passing in 14/12 GHz Band Satellite Communication System

T. Hatsuda, N. Okuno, R. Mitsuhashi, Y. Aoki, F. Takahata, H. Echigo

15th General Assembly of the international union of radio science C8.2 157 1996.07 [Refereed]
北海道統合通信網における短・長距離局間のSD特性の検討

奥野,成田, 西浦,三橋, 青木,高畑, 越後,初田

電子情報通信学会技術報告 SAT96-69 81 - 96 1996.07 [Refereed]
N-STAR移動体衛星通信のサービスインによせて

高畑

NTT DoCoMoテクニカル・ジャーナル 4 ( 2 ) 4 - 5 1996.07 [Refereed]
電波利用の課題について

高畑

周波数資源開発シンポジウム'96 1996.06 [Refereed]
Satellite channel assignment method with control of call-loss probability for carriers with different transmission bandwidths under frequency-division multiple access

M Hayashi, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 79 ( 4 ) 63 - 74 1996.04 [Refereed]

　View Summary

In the satellite communication system with frequency-division multiple access (FDMA), the efficient use of the frequency band is very important. This paper discusses the channel assignment method which can realize a high channel utilization for three kinds of information with different bandwidths while efficiently controlling the call loss probability.
As conventional methods, the orderly assignment method, which is known to realize a high channel utilization, as well as the separate assignment for each kind of call, where the odd effect is not produced, are considered. For the purpose of this study, the floating boundary assignment (FA) is considered, which is based on the orderly assignment and a new channel search algorithm so that the call loss probability can be controlled. The proposed method is compared to the conventional methods.
First, it is shown by the performance evaluation by simulation that the FA method can realize a high channel utilization and the call loss probability control. Using the satellite communication system based on the demand-assignment scheme, the performance of the FA method is partially examined by experiment. By assuming a precise requirement for the call loss probability, the call loss probability control performance as well as the channel utilization are examined. The proposed FA method is shown to be useful through the comparison.
16値QAMに基づく広帯域陸上移動無線用復調器の構成と特性

境田,高畑

1996年電子情報通信学会総合全国大会 B-439 1996.03 [Refereed]
Kuバンド・ディジタル衛星通信における干渉特性のモデル化に関する検討

関崎, 江幡,高畑

1996年電子情報通信学会総合全国大会 B-263 1996.03 [Refereed]
直接拡散スプレッド・アロハ方式のスループット特性について

笹森,高畑

1996年電子情報通信学会総合全国大会 B-247 1996.03 [Refereed]
直接拡散スプレッド・アロハ方式に適した復調方式の構成と特性

菊田,高畑

1996年電子情報通信学会総合全国大会 B-246 1996.03 [Refereed]
スペクトル拡散通信におけるビット誤り率特性の導出について

堀越,高畑

1996年電子情報通信学会総合全国大会 B-245 1996.03 [Refereed]
北海道統合通信網におけるJCSAT衛星を利用したSD特性の測定

奥野,小上, 小島,長瀬, 三橋,青木, 高畑,初田

1996年電子情報通信学会総合全国大会 B-224 1996.03 [Refereed]
種類の異なるディジタルPSK信号間の捕捉効果について

高津, 有賀,高畑

1996年電子情報通信学会総合全国大会 B-223 1996.03 [Refereed]
マルチビーム周回衛星通信システムにおける衛星配置に関する検討

平,高畑

1996年電子情報通信学会総合全国大会 B-212 1996.03 [Refereed]
Propagation Characteristics Expoeriment via JCSAT for the Hokkaido Integrated Telecommunication Network

T. Hatsuda, R. Mitsuhashi, H. Inoue, Y. Aoki, F. Takahata

Memoirs of the Hokkaido Institute of Technology 24 ( 2 ) 136 - 145 1996.03 [Refereed]
16値QAM変調方式を適用した広帯域陸上移動通信用復調器の一構成法

境田,高畑

電子情報通信学会研究技術報告 RCS95-161 25 - 30 1996.02 [Refereed]
Transmission efficiency of spread ALOHA system using unified spread-spectrum code

F Sasamori, F Takahata

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 79 ( 1 ) 107 - 115 1996.01 [Refereed]

　View Summary

This paper considers the direct-spread ALOHA system using the same spread-spectrum code where the individual packet signals are separated using the time compression of the output signal from the matched filter in the demodulator. A method is shown to derive theoretically the transmission efficiency of the system and then the performance of the spread ALOHA system of the spread code length of seven chips is shown as an example. The transmission efficiency (channel traffic performance and the throughput) of the system is compared to that of the conventional slotted ALOHA system and discussed quantitatively. It is shown that the spread ALOHA system can realize a good performance with a low peak transmitted power.
Long distance site diversity characteristics measurement results vis JCSAT by using one earth station measuring method

T Hatsuda, N Okuno, H Nagase, K Kojyo, K Kojima, R Mitsuhashi, Y Aoki, F Takahata, H Eohigo

IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM - 1996 DIGEST, VOLS 1-3 3 1872 - 1875 1996 [Refereed]
直接スペクトル拡散方式におけるビット誤り率特性の一導出法

堀越,高畑

電子情報通信学会研究技術報告 SAT95-60 7 - 12 1995.10 [Refereed]
周回衛星通信システムにおける衛星配置と回線接続特性に関する解析

平,高畑

電子情報通信学会研究技術報告 SAT95-59 1 - 6 1995.10 [Refereed]
北海道統合通信網の構築に必要な電波伝搬特性の測定法の検討と測定結果

奥野,小上, 小島,長瀬, 三橋,青木, 高畑,初田

電子情報通信学会研究技術報告 SAT95-57 73 - 78 1995.09 [Refereed]
直接拡散スプレッドアロハ通信用復調器の一構成法

菊田, 松本,高畑

電子情報通信学会研究技術報告 SAT95-6 67 - 74 1995.04 [Refereed]
伝送帯域の異なるFDMA衛星回線に対する呼損率制御可能な回線割当制御方式の検討

林,高畑

電子情報通信学会論文誌 J78-B-II ( 4 ) 231 - 239 1995.04 [Refereed]
The Study and Experiment on Satellite Communications by Universities

F. Takahata

Journal of the Asia Pacific Telecommunity/Asia Pacific Telecommunity 7 ( 2 ) 31 - 32 1995.04 [Refereed]

CiNii
AN APPLICATION OF CHIRP TO SPREAD-ALOHA SYSTEM

M ENOMOTO, F TAKAHATA

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 78 ( 1 ) 72 - 81 1995.01 [Refereed]

　View Summary

This paper proposes a spread-ALOHA system using chirp. The system is composed of the modulator containing the chirp filter and the demodulator containing the chirp matched filter, the quasi-coherent detector and the block demodulator. In the proposed system, the data transmission is realized by using the chirp signal with phase information corresponding to binary data and then, using the chirp effect, the frequency component of the transmitted signal is spread continuously. In addition, since the respective bits composing a packet are compressed in time by the correlation processing using the chirp matched filter, the multiplexed packets are separated in individual packets based on the timing difference among the received packets.
The carrier synchronization, which is required in the demodulation process, is achieved by quasi-coherent detection and the block demodulation. The frequency and the phase offset occurring in the quasi-coherent detection are corrected by a method of highly accurate frequency detection based on the fast-Fourier transform in the block demodulator. Furthermore, assuming various conditions, quantitative evaluations are made on the bit-error rate performance by means of computer simulation. It is verified that a high interference immunity is realized by the frequency spread using chirp, and frequency offset generated in the quasi-coherent detection is well estimated and corrected.
同一の拡散符号を用いたスプレッドアロハ方式の伝送効率

笹森,高畑

電子情報通信学会論文誌 J77-B-II ( 11 ) 726 - 732 1994.11 [Refereed]
UNIQUE WORD DETECTION USING QUANTIZED SOFT-DECISION DATA

H SASAI, M TAKEYABU, K MINOMO, F TAKAHATA, J OGIKUBO

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 77 ( 2 ) 80 - 93 1994.02 [Refereed]

　View Summary

The efficacy of applying quantized soft decision data to unique word (UW) detection, which plays an important role in frame synchronization in digital radio transmission systems, is discussed considering hardware implementation. This UW detection method represents the received signal vector using representative points within a multidimensional space and measures the Euclidean distance from the vector point corresponding to the UW pattern.
Probability calculations are employed for obtaining theoretically UW detection characteristics such as missed detection and false detection, assuming that white Gaussian noise is added to the signal during transmission. These various characteristics are then compared quantitatively with the characteristics obtained by the conventional UW detection method using hard decision data. In addition, the UW detection characteristics obtained experimentally using hardware are presented. As a result of the quantitative evaluations, it has been clarified that the application of soft decision data is effective in reducing the UW length required for objectives of the UW detection performance associated with frame synchronization characteristics.
スプレッドアロハ方式へのチャープの適用

榎本,高畑

電子情報通信学会論文誌 J76-B-II ( 11 ) 864 - 871 1993.11 [Refereed]
衛星搭載機能の周波数有効利用に対する効果

筋誡

電子情報通信学会論文誌 J76-B-II ( 11 ) 920 - 923 1993.11 [Refereed]
FIELD TRIAL AND PERFORMANCE OF LAND MOBILE MESSAGE COMMUNICATIONS USING KU-BAND SATELLITE

F TAKAHATA, Y HOSHINO, T BABA, H KOMATSU, M OKUDA

IEICE TRANSACTIONS ON COMMUNICATIONS E76B ( 2 ) 120 - 130 1993.02 [Refereed]

　View Summary

A field trial was conducted to evaluate the technical performance of land mobile message communication in different environments. The OmniTRACS system and the Ku-band JCSAT satellite were utilized as the mobile communications system and the satellite, respectively. The trial took place in September 1990 at different areas in Japan. Data collected correspond to about 65 hours of operation, during which a large number of messages were sent via the satellite. Two land mobile terminals operated simultaneously, each terminal having a function of generating messages automatically which simulates a large volume of traffic corresponding to about 50 terminals. Thus, the system was evaluated under the condition that 100 mobile terminals were in operation. Obtained data have been analyzed with a particular focus on the message transmission correlating with actual environments. The analysis was done by classifying environments into five categories: overall condition, type of roads, terrain, areas and weather conditions. The average transmission count per message experienced under all conditions is equal to 1.432 for forward messages transmitted from the hub station to mobiles, and 1.157 for return messages transmitted from mobiles to the hub station. With respect to the classification by the type of roads, for enample it becomes obvious that the performance is generally good except along roads of North-South orientation through dense urban areas. It is concluded that the message communications from/to mobiles are feasible in a wide range of environments, with the performance of success essentially depending on the visibility of satellite.
量子化された軟判定データを用いたユニークワード検出

笹井,竹薮, 蓑毛, 荻窪,高畑

電子情報通信学会論文誌 J75-B-II ( 12 ) 873 - 883 1992.12 [Refereed]
Present Situation and Perspectives of VSAT Systems

F. Takahata

The Journal of the Asia-Pacific Telecommunity 4 ( 3 ) 20 - 22 1992.09 [Refereed]
Theory and Performance of Frequency Assignment Schemes for Carriers with Different Bandwidths under Demand Assignment SCPC/FDMA Operation

K. Chiba, F. Takahata, M. Nohara

IEICE Transactions on Communications E75-B ( 6 ) 476 - 485 1992.06 [Refereed]
Keynote Address - Present Situation and Perspectives of VSAT Systems -

F. Takahata

Seminar on VSAT Applications 1992.05 [Refereed]
Design of a PSK modulation/demodulation method free from interruptions

Masami Yamazaki, Yusuke Tomoda, Fumio Takahata

Electronics and Communications in Japan (Part I: Communications) 75 ( 9 ) 101 - 115 1992 [Refereed]

　View Summary

This paper discusses a PSK modulation/demodulation method free from interruptions providing continuous telecommunication services. The feature of the system is that the transmission rate or the carrier frequency is switchable without interruptions during communications. Functions of the system are outlined. The design procedure and design results are presented. Another feature of the proposed method is its transmission format. In the normal operation, a control information is inserted into the transmission format and a preamble is inserted only when the transmission rate or the carrier frequency is to be changed. By this elaboration, interruptions can be avoided. As a detailed example of the design, a link configuration is assumed where the convolution encoding Viterbi decoding with coding rate of one‐half is used as the forward error correction scheme, and the information rate is made variable among 2B + D, B + D, and D based on the basic ISDN service. Parameters concerning the transmission format and the modulation/demodulation are determined. The control information and protocol required in the functional switching needed in avoiding interruptions are also discussed. By this method, limited radio frequency resources can efficiently be utilized, appropriately varying the transmission rate according to traffic or switching the carrier frequency. Copyright © 1992 Wiley Periodicals, Inc., A Wiley Company

DOI
ますます高まる日本への期待「テレコム’91の出展を見て」

高畑

ITUジャーナル 21 ( 12 ) 1991.12 [Refereed]
瞬断回避PSK変復調方式の設計

山崎, 友田,高畑

電子情報通信学会論文誌 J74-B-II ( 12 ) 656 - 666 1991.12 [Refereed]
マルチビーム衛星の配置とビーム照射方向の最適化

五十嵐,高畑

電子情報通信学会論文誌 J74-B-II ( 12 ) 687 - 698 1991.12 [Refereed]
21世紀を指向する衛星通信

高畑

Renta Station 4 ( 3 ) 1991.05 [Refereed]
身近な存在の地位確立(衛星通信)

高畑

日本工業新聞 1991.01 [Refereed]
地球を取り巻く宇宙空間の将来像

高畑

ファイナンス 26 ( 1 ) 1990.04 [Refereed]
A Traffic Assignment Algorithm Minimizing Transmission Capacity Required in Paths

F. Takahata, A. Mochizuki

Memories of the School of Science & Engineering, Waseda Univ. 53 57 - 83 1990.03 [Refereed]
衛星通信技術の流れ

高畑

情報通信学会誌 7 ( 3 ) 9 - 17 1989.11 [Refereed]
A PSK GROUP MODEM BASED ON DIGITAL SIGNAL-PROCESSING - ALGORITHM, HARDWARE DESIGN, IMPLEMENTATION AND PERFORMANCE

F TAKAHATA, M YASUNAGA, Y HIRATA, T OHSAWA, J NAMIKI

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 6 ( 3 ) 253 - 266 1988.07 [Refereed]
Field Test of Ku-band Transmission Using Small-dish (IBS) Earth Stations

Y. Takeuchi, M. Nohara, F. Takahata

16th Int. Symposium on Space Technology and Science n-4-4 2105 - 2112 1988.06 [Refereed]
An Up-link Power Control for Demand Assignment/International Business Satellite Communications Network

M. Nohara, Y. Takeuchi, F. Takahata

16th Int. Symposium on Space Technology and Science 1988.06 [Refereed]
ディジタル衛星回線における不稼動率の推定法

武内,高畑

電子情報通信学会論文誌 J71-B ( 5 ) 640 - 649 1988.05 [Refereed]
Development of a Demand Assignment/TDMA System for International Business Satellite Communications

M. Nohara, Y. Takeuchi, F. Takahata, H. Hirata, Y. Yamazaki

IEEE Global Telecommunications Conference (GLOBECOM'87) 10.4 1987.11 [Refereed]
FEC Combined Burst-Modem for Business Satellite Communications Use

K. Murakami, M. Miyake, T. Fuji, Y. Moritani, T. Fujino, K. Ito, F. Takahata

IEEE Global Telecommunications Conference (GLOBECOM'87) 8.2 1987.11 [Refereed]
Recent Developments of On-board Processing Technologies in Japan

F. Takahata, H. Shinonaga, M. Ohkawa

3rd Tirrenia International Workshop on Digital Communications 235 - 242 1987.09 [Refereed]
Experimental IBS Small-dish Earth Station

H. Hirata, G. Satoh, F. Takahata, M. Nohara, K. Inagaki, S, Endo

IEEE International Conference on Communications (ICC'87) 8.5 1987.06 [Refereed]
A PSK GROUP MODEM FOR SATELLITE-COMMUNICATIONS

F TAKAHATA, M YASUNAGA, Y HIRATA, T OHSAWA, J NAMIKI

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 5 ( 4 ) 648 - 661 1987.05 [Refereed]
AN OPTIMUM TRAFFIC LOADING TO INTERSATELLITE LINKS

F TAKAHATA

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 5 ( 4 ) 662 - 675 1987.05 [Refereed]
PSK Group MODEM and its Performance

F. Takahata, O. Ichiyoshi, K. Yano

IEEE Global Telecommunications Conference (GLOBECOM'86) 47.3 1986.12 [Refereed]
デマンド割当て/国際ビジネス衛星通信システムの設計)

野原,武内, 山崎, 高畑,平田

電子通信学会論文誌 J69-B ( 11 ) 1219 - 1230 1986.11 [Refereed]
A Demand Assignment Control in International Business Satellite Communications Network

M. Nohara, Takeuchi, F. Takahata, H. Hirata

7th International Conference on Digital Satellite Communications 215 - 222 1986.05 [Refereed]
A Network Architecture for International Business Satellite Communications

F. Takahata, M. Nohara, Y. Takeuchi

15th International Symposium on Space Technology and Science 913 - 918 1986.05 [Refereed]
International Connection of Plesiochronous Networks via TDMA Satellite Link

Kazunori Inagaki, Yasuo Hirata, Fumio Takahata, Akira Ogawa, Kunihiko Niwa

IEEE Journal on Selected Areas in Communications 1 ( 1 ) 188 - 198 1983 [Refereed]

　View Summary

Digital transmission techniques are expected to spread throughout the fixed-satellite service in the near future. The introduction of digital satellite systems will lead to a new requirement regarding how to connect the satellite link with terrestrial digital networks. This paper presents a satellite/terrestrial digital interface that has been developed to interconnect 2.048 Mbit/s PCM terrestrial and INTELSAT TDMA links which are in the plesiochronous relationship. Major functions of the interface include frame slip control, compensation for path length variation, and rate and format conversions. This paper also describes the design and implementation of the developed equipment, and experimental results for signal impairment due to the frame slips and PCM multiplex standard conversion. The experimental results demonstrate that a large number of bit errors are induced by frame slips for voiceband data transmission above 4800 bits/s. Copyright © 1983 by The Institute of Electrical and Electronics Engineers, Inc.

DOI
International Connection of Plesiochronous Networks via TDMA Satellite Link

K. Inagaki, H. Hirata, F. Takahata, A. Ogawa, K. Niwa

IEEE International Conference on Communications (ICC'82) 5H.4 1982.06 [Refereed]
A DIGITAL 60 CHANNEL TRANSMULTIPLEXER - ALGORITHM MINIMIZING MULTIPLICATION RATE AND HARDWARE IMPLEMENTATION

F TAKAHATA, K INAGAKI, Y HIRATA, A OGAWA

IEEE TRANSACTIONS ON COMMUNICATIONS 30 ( 7 ) 1511 - 1519 1982 [Refereed]
Design of Digital Signal Processor in a TDM/FDM Transmultiplexer

F. Takahata, K. Inagaki, A. Ogawa

IEEE International Conference on Communications (ICC'80) 47.2 1980.06 [Refereed]
Development of a TDM/FDM Transmultiplexer

F. Takahata, Y. Hirata, A. Ogawa, K. Inagaki

IEEE Transactions on Communications COM-26 ( 5 ) 726 - 733 1978.05 [Refereed]
24チャネルトランスマルチプレクサ

高畑, 平田,稲垣

電子通信学会論文誌 61-B ( 1 ) 24 - 31 1978.01 [Refereed]

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Books and Other Publications

ディジタル無線通信入門

髙畑文雄, 前原文明, 笹森文仁

培風館 2002.06 ISBN: 9784563014872
信号表現の基礎(CD-ROM付)

髙畑文雄

社団法人電子情報通信学会 1998.09 ISBN: 4885521556
宇宙技術入門

髙畑文雄, 森英彦, 池内了, 輿石肇, 戸田勧, 新田慶治

オーム社 1994.09 ISBN: 4274022668

Research Projects

New Generation Satellite Network and Inter-university System

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1994

　

　

TAKAHATA Fumio, PARK Y., LEE C., LEE J., TANAKA Y., ONOZATO K., TOMINAGA H., KOMATSU N.

　View Summary

The appearance of advanced satellites with high power and the cost reduction of earth stations enabled universities to conduct experiments using actual satellites. Taking account of this situation, the University^<, >s Joint Study Group for Digital Satellite Communications (UnSAT JSG) has been established, in which more than forty universities in Japan, two universities each in Korea and China join and about thirty universities are actually carrying out experiments using their own earth stations via Ku-band satellite. The experiments cover a variety of study fields such as radio propagation characteristics, communications scheme, network structure between universities, transmission and security of video, image and computer data. Considering that satellites have an inherent potential to provide borderless communications, it is expected by the international cooperation that the experiments via satellite will widely spread over the Asia-Pacific region in the near future
Study on Spread Spectrum Packet Communications

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1993

-

1994

TAKAHATA Fumio

　View Summary

A spread ALOHA system using a unified spread spectrum code is discussed in terms of its performance, design and transmission efficiency. The system is outlined and then the bit error performance under two conditions is derived by a theoretical analysis and an approximate method. The comparison it with the results obtained by means of computer simulation indicates that the theoretical results coincide perfectly with the simulated ones and that the approximayte results coincide with the simulated results in the low E_b/N_0 range. A demondulator is designed focussing on symbol timing recovery and carrier recovery. It is proposed that the provision of a short preamble enables to apply a synchronous cyclic addition to these recoveries. It is concluded as a result of performance evaluation concerming symbol timing detection and carrier offset estimation that the proposed scheme improves the performance remarkably. The transmission efficiency obtained in the spread ALOHA system is derived for three cases. Comparing quantitatively the transmission efficiency in the first case with that of the conventional slotted ALOHA system under the condition at the same frequency bandwidth, it is concluded that the spread ALOHA system gives a good performance with the lower transmitting power compared with that of the slotted ALOHA system. As for the other two cases, the system using a unified spread spectrum code is compared with that using different spread spectrum codes in terms of transmission efficiency and it becomes obvious that the former system provides better performance for the long packet length than the latter one. Finally it is proposed to realize a spread-ALOHA system by using a chirp signal. Correlation process using the chirp matched filter is theoretically described at first and signal processings to be performed in the receiving side are clarified, in particular focussing on the block demodulator. The quantitative evaluation under various conditions is discussed concerning bit error rate performance obtained by means of computer simulation
Syudy on Frame Synchronization Methods for Digital Satellite Communications System

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1990

-

1991

TAKAHATA Fumio

　View Summary

Frame synchronization is an essential function for providing digital transmission services in digital satellite communications systems. It consists of a detection of frame synchronization pattern called "Unique Word (UW)", and an establishment of synchronization by detecting UWs consecutively. The UW detection in the receiving side is realized based on Euclidian distance between received signal vector and UW vector in multi-dimentional space, the dimension of which coincides with the length of UW. An application of quantized soft-decision data to UW detection is discussed from the practical point of view, and a theoretical and experimental approaches are established for obtaining a variety of UW detection characteristics. The obtained performance such as unique word missed, false detections and so on is quantitatively evaluated, compared with that of conventional hard-decision data and non-quantized soft-decision data. It is concluded from the quantitative evaluation that the application of quantized soft-decision data has potential to realize effectively the UW detection complying with design objective. With respect to the frame synchronization, a theoretical approach is established for calculating a variety of frame synchronization characteristics from those of UW detection. It becomes obvious from the quantitative evaluation that the UW detection using soft-decision data provides better performance on the criteria of reframe time and sync loss detection & reframe time in the low C/N condition, compared to the use of hard-decision and non-quantized soft-decision data
次世代衛星ネットワ-クシステムと大学間共同利用に関する総合的研究

　View Summary

通信と放送はそれを実現する基本的な技術は同類のものであり共通な機能も多くあったが、施設や機器の運用制度や利用形態の差が個々の技術の差となって現れた。このことにより通信衛星と放送衛星の区別が生じ、技術開発のプロセスとその運用制度も区別されたものとして発達しているが、技術開発の本質はこれらの運用制度の壁を越え、コンピュ-タと映像の融合とともに放送に通信のサ-ビス機能の区別が全く意味をなさなくなってきている。衛星を用いた媒体においても通信と放送とコンピュ-タを統合したサ-ビス機能の実現が予想される。この研究の主題である「次世代衛星ネットワ-クシステム」とは、家庭やオフィスの端末はもとより、自動車や飛行機等の移動体や、人の携帯する端末に対し、高詳細な画像や音声、デ-タを含んだ情報を、従来の通信的な機能と放送的な機能の両方を実現しうる衛星によるネットワ-クシステムのことである。このような研究開発は、従来、供給者側の視点から行なわれている。すなわち、NTTやNHKなどの事業者の立場での開発が先行しており、またこれを制度的に規制し、バックアップする郵政省等による行政指導によって行なわれている。このことは、利用者側の視点による技術開発がともすると蔑ろにされたために、真に利用者の利便性を重視したシステム開発のための基礎研究の遅れを生む結果となった。これらの歪みを正すために利用者側の視点で基礎研究を行なうことが重要であり、文部省科学研究費補助金重点領域研究の必要性がある。すなわち、本研究は大学を中心とした教育・研究の場において必要である情報通信のインフラストラクチャを構築するための基礎研究を行なうに当たり、何を研究すべきかを調査した結果である