2L支路SSC-MRC混合分集及其性能分析

Analysis of SSC-MRC hybrid diversity combining technique

分集合并技术是对抗多径衰落的有效手段,而常见的单纯分集合并技术如最大比合并(MRC)、等增益合并(EGC)、选择合并(SC)以及切换驻留合并(SSC)等在系统复杂度和系统性能之间存在矛盾;所以有必要寻找一种工程易于实现同时性能也可以接受的混合分集合并方式.在此将低成本、结构简单的SSC分集与最优性能的MRC分集结合,即SSC-MRC混合分集合并技术.推导了2L条独立同分布瑞利衰落信道下SSC-MRC混合分集的输出信噪比概率密度函数(PDF)以及BPSK信号下误码率表达式,还分析了门限选取对系统的影响.仿真实验表明,四支路SSC-MRC混合分集性能稍差于四支路MRC,但重要的是节省了2台接收机,大大减少了成本和系统复杂度.

Diversity combining technique is an effective means against multi-path fading,and it has contradiction between system complexity and system performance in normal diversity combining like MRC（maximal-ratio combining）,EGC（equal gain combining）,SC（selective combining）,SSC（switch-and-stay combining）,etc.So it is necessary to look for a new combining technique,which is easy to be realized and has acceptable performances.The hybrid diversity combining technique SSC-MRC combines the low cost and simple structure of SSC and the high performance of MRC.The authors derived the expression of SSC-MRC hybrid combining for output SNR PDF（probability density function） and BER（bit error rate） with BPSK（binary phase shift keying） signal in case of 2L branches in Rayleigh fading channel and analyzed the influence of system with variable threshold.Experimental results show that the performance of four branches SSC-MRC hybrid diversity combining is not as good as four branches MRC,but it matters that the hybrid diversity combining can save two receivers,which greatly reduces the cost and system complexity.