A study on nonsquare differential space-time coding for massive MIMO-OFDM communications

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H07036
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Communication/Network engineering
• Research Institution: Hiroshima City University
• Principal Investigator: Ishikawa Naoki 広島市立大学, 情報科学研究科, 助教 (00801713)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 大規模アンテナアレイ / 情報理論 / 差動符号化 / 非同期検出 / 空間変調 / インデックス変調 / 順列変調 / 非正方射影

Outline of Final Research Achievements

In this research topic, I have established a basic concept that converts the conventional square-matrix-based differential family into a high-rate nonsquare counterpart, where a novel square-to-nonsquare projection is invoked. I, Dr. Xu Chao, and Dr. Rakshith Rajashekar have analyzed this family in terms of the constrained capacity, cardinality, detection complexity, and reliability. The transmission rate of the conventional square differential scheme decays as the number of transmit antennas increases, which has been a well-known open issue since 2000. The proposed unique projection method solves this issue and achieves a significantly higher transmission rate than the conventional reference scheme. As a result, I have succeeded in establishing the basic framework of the nonsquare differential space-time coding concept.

Free Research Field

無線通信

Academic Significance and Societal Importance of the Research Achievements

本研究成果は過去20年間に渡って研究されてきた差動符号化方式の課題を解決する唯一の方式である。直交性のある正方行列（ユニタリ行列）を非正方行列に射影し、非直交にも関わらず直交しているかのようにチャネル推定不要の非同期検出を可能とする点が特に独創的だと考えている。送信レートが非常に高く通信オーバーヘッドが小さいという利点を活かし、無線通信デバイスのバッテリ消費削減に加え、モノのインターネットや小型ドローンの無線制御などへの応用が期待できる。