Low-complexity optimal spatial channel pairing for AF-based multi-pair two-way relay networks

This paper considers a multi-pair two-way relay system with multi-antenna users and proposes a low-complexity optimal spatial channel pairing (SCP) strategy at the relay station (RS) for such a system. The proposed SCP scheme, following the BD-like beamformer at RS, pairs the uplink spatial subchannels of each user pair with the corresponding downlink spatial subchannels by maximizing sum-rate (Max-SR). Furthermore, a new mathematical inequality (arrangement inequalities of a product) is developed and applied to obtain sufficient and necessary conditions for achieving Max-SR-SCP. This also yields a simple low-complexity implementation of the proposed SCP in contrast to the NP-hard complexity of the original Max-SR-SCP problem. Simulation results illustrate that the proposed Max-SR-SCP achieves substantial sum-rate gains over other pairing schemes.摘要针对多用户对双向中继无线网络中块对角化波束成形算法, 设计一种低复杂度最大化和速率的空间信道配对方法。 所提出最大化和速率方案, 以最大化系统和速率为代价函数, 在中继站将每个用户上行链路的空间子信道与其相应的下行链路的空间子信道进行最优配对。 为了推导最优信道配对方法的闭合表达式, 本文提出并证明了一个新的数学不等式定理-连乘排序不等式定理, 并应用该定理证明了最大化和速率空间信道配对方法的充分必要条件, 从而获得该方法的解析公式。 仿真结果表明: 我们提出的最大化和速率空间信道配对方法同其他的空间信道配对方法相比能实现显著的和速率提升。