结合波束形成的双向中继选择策略

Two-way relay selection strategy combined with beamforming

为了增强多天线信源和多个单天线双向中继通信系统的传输性能,并降低信号处理复杂度,提出一种结合波束形成的最优中继选择策略.各个中继只需利用本地信道状态信息进行分布式的选择,2个信源分别利用最大比发送(MRT)和最大比合并(MRC)准则设计发送和接收波束形成向量.利用信道的统计特性,在瑞利衰落信道下分析新传输策略的中断概率性能,推导了系统中断概率的闭合表达式.对新策略与其他5种策略进行了仿真对比分析.结果显示,新传输策略的中断概率明显优于基于路径、基于和速率、基于误符号率、随机单中继选择和等功率多中继并行传输这5种策略,且随着中继数和天线数的增加,新策略可充分利用多中继和多天线分集提升系统中断概率性能.

To enhance transmission performance of multi-antenna source and multiple single-antenna two-way relay communication systems with decreased signal processing complexity,an optimal relay selection combined with beamforming scheme was proposed.The relay selection was performed by only local channel state information in a distributed way,and the transmitting and receiving beamforming vectors were realized according to two sources by maximum-ratio-transmission（MRT） and maximum-ratio-combining（MRC） rules.Based on the channel statistical property,the outage probability performance of the new scheme was analyzed in Rayleigh fading channels to deduce the closed expression of the system outage probability.The new scheme was simulated to compare with other five schemes.The results show that outage probability of the new transmission scheme is obviously better than those based on the path,sum rate,symbol error ratio,opportunistic single relay selection and equal-power multiple relays transmission.The system outage probability of the new scheme is improved with the increase of relay and antenna number,since the multi-relay and multi-antenna diversities can be fully utilized.