multi-carrier differential trellis-coded modulation/demodulation for severe doubly-selective channel environment

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04382
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21020:Communication and network engineering-related
• Research Institution: Ritsumeikan University
• Principal Investigator: Kubo Hiroshi 立命館大学, 理工学部, 教授 (40633243)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 通信方式 / 変復調 / 信号処理 / 移動体通信 / 音響通信

Outline of Final Research Achievements

This research investigates on multi-carrier trellis coded modulation/demodulation schemes, in order to improve performance on severe doubly-selective channel environments in the presence of fast time variation and large delay spread of channels. This research has proposed the following two schemes: 1) differential trellis coded modulation and its demodulation scheme employing channel prediction for fast time-varying channels; 2) multi-carrier modulation schemes employing differential encoding in the time direction for large delay spread channels. It has been confirmed that the combination schemes of 1) and 2), i.e., multi-carrier trellis coded modulation/demodulation schemes, have excellent performance in the severe doubly-selective channel environments, whose selectivity is five times larger than that considered in the conventional modulation/demodulation schemes.

Free Research Field

無線通信

Academic Significance and Societal Importance of the Research Achievements

２重選択性の厳しさは伝搬環境の時間変動と遅延時間広がりから規定され，最大ドップラー周波数と遅延時間差の積（パラメータfDτD）にて定量的に評価できる．従来の移動体通信では0.5%程度以下のfDτDを検討するのが一般的であり，1%以上のfDτDに対応することは困難であった．本研究の成果により，従来技術が対応可能なfDτDの約5倍の約5%程度のfDτDに対応する無線伝送方式が確立できた．
本研究の技術確立により，時速500kmを超える移動速度で数十kmのカバーエリアを実現する高速鉄道用の空間波列車無線，移動速度が3knotを超える水中音響通信にて，高品質・高信頼通信を実現することが可能となる．