单天线中继辅助视距MIMO系统渐近容量及中继策略的研究

Research on asymptotic capacity and relay strategy for line-of-sight MIMO systems aided by single antenna relay

研究了视距环境下单天线中继节点辅助MIMO系统的信道模型及容量。针对系统容量与众多因素相关和表达式复杂的问题,根据天线阵列波束相关性及MIMO信道的特点,得出了具有简洁结构的系统渐近容量表达式,进而基于该表达式提出了中继节点最佳位置选择的方法,并与加入中继节点前的系统容量进行了比较,得到了中继选择策略。数值计算与分析结果表明,系统渐近容量具有很好的渐近特性,基于渐近容量的中继策略性能优异并具有很好的鲁棒性。同时渐近容量和中继策略运算复杂度低,适合工程应用。

In this paper, the channel model and capacity for multiple-input multiple-output （MIMO） systems aided by single antenna relay in the line-of-sight（LOS） environment are investigated. In view of the problems that the system capacity relates to varieties of factors and is usually hard to be expressed in formulation, the asymptotic capacity of the systems is expressed in a compact form. Based on the characteristics of MIMO channels and the beam correlation of antenna arrays, An optimal position selection strategy for relay nodes is derived to maximize the asymptotic capacity. Then a relay selection strategy is proposed based on the capacity comparison with the traditional LOS MIMO systems. Finally, numerical analysis results are presented. The accuracy of the asymptotic capacity as well as the performance and robustness of the relay strategy are verified. Moreover, the asymptotic capacity and relay strategies are applicable for practical systems due to the low computational complexity.