基于正交空间调制的认知协作系统性能分析

Performance Analysis of Cognitive Cooperative Systems Based on Quadrature Spatial Modulation

针对信道间干扰、天线间同步等问题,提出了基于正交空间调制的认知协作通信系统。该系统采用均值功率分配算法,中继节点和目的节点采用最大似然检测算法。推导了随机中继选择、次优中继选择和最优中继选择3种方案下中断概率的准确闭合表达式,以及在高信噪比区域的渐进表达式,并分析了系统的分集增益。蒙特卡罗仿真结果表明:与随机中继选择相比,次优中继选择和最优中继选择方案可以明显降低系统的中断概率,有效提高系统增益。

The cognitive cooperative communication system based on quadrature spatial modulation(QSM)is proposed to solve the problems of inter-channel interference and inter-antenna synchronization.The mean power allocation algorithm is used to analyze performance of the system.In addition,the relay nodes and the destination node decode their received signals with the maximum likelihood detection algorithm.The exact closed expressions of outage probability under random relay selection(RRS),suboptimal relay selection(SRS)and optimal relay selection(ORS)are derived respectively.The approximate outage probabilities in the high signal-to-noise ratio region are derived,and the diversity gains of three relay selection strategies are analyzed.The Monte Carlo simulation results show that SRS and ORS can obviously reduce the outage probability and effectively improve the gain of the system compared with RRS.