Multiple-Input Multiple-Output Two-Way Relaying: A Space-Division Approach

作     者：Yuan, Xiaojun Yang, Tao Collings, Iain B. 

作者机构：Chinese Univ Hong Kong Inst Network Coding Hong Kong Hong Kong Peoples R China CSIRO ICT Ctr Marsfield NSW 2122 Australia 

出 版 物：《IEEE TRANSACTIONS ON INFORMATION THEORY》 (IEEE Trans. Inf. Theory)

年 卷 期：2013年第59卷第10期

页      面：6421-6440页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 0701[理学-数学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：University Grants Committee of the Hong Kong [418712, AoE/E-02/08] CSIRO OCE Postdoctoral Fellowship 

主　　题：Multiple-input multiple-output (MIMO) physical-layer network coding space-division precoding two-way relay channel (TWRC) 

摘      要：We propose a novel space-division-based network-coding scheme for multiple-input multiple-output (MIMO) two-way relay channels (TWRCs), in which two multiantenna users exchange information via a multiantenna relay. In the proposed scheme, the overall signal space at the relay is divided into two subspaces. In one subspace, the spatial streams of the two users have nearly orthogonal directions and are completely decoded at the relay. In the other subspace, the signal directions of the two users are nearly parallel, and linear functions of the spatial streams are computed at the relay, following the principle of physical-layer network coding. Based on the recovered messages and message-functions, the relay generates and forwards network-coded messages to the two users. We show that, at high signal-to-noise ratio, the proposed scheme achieves the asymptotic sum-rate capacity of the MIMO TWRC within 1/2 log (5/4) approximate to 0.161 bits per user-antenna, for any antenna configuration and any channel realization. We perform large-system analysis to derive the average sum-rate of the proposed scheme over Rayleigh-fading MIMO TWRCs. We show that the average asymptotic sum-rate gap to the capacity is at most 0.053 bits per relay-antenna. It is demonstrated that the proposed scheme significantly outperforms the existing schemes.