基于不同信道信息的协作系统预编码矩阵的设计

摘要

基于完备和不完备2种信道状态信息,研究协作系统源和中继节点处联合空时编码的预编码设计问题.通过分析接收信噪比(signal-to-noise ratio,SNR)和给定调制方式下的误符号率(symbol error rate,SER),建立预编码矩阵的优化问题.鉴于问题的非线性和非凸性,采用两步走的方法:第1步,确定2个预编码矩阵的最优方向;第2步,将原联合优化问题分解为2个独立的子问题,大大降低求解的复杂度.计算机仿真结果表明:联合空时分组码(space-time block codes,STBC)的预编码系统,其误码性能优于单空时分组码的系统,且发送端的相关性越大,性能增益提高得越明显,尤其是在低信噪比条件下表现得更加优越.因此,采用预编码矩阵的设计可以有效提升空时编码协作系统的误码性能.%It was focused on precoding of space-time block codes(STBC)for cooperative system with different channel state information.To improve the performance of relay network, it was established the optimization problems to minimize the symbol error rate(SER)based on statistical channel state information(CSI)and maximize the minimum signal-to-noise ratio based on perfect CSI.Considering the complex of the problems,it was provided a two-step approach to solve them.In the first step the optimization directions were determined. In the second step,the original joint problem was decomposed into two independent sub-problems which could be solved in lower complexity.Simulation results showed that the precoding system combined with orthogonal STBC outperforms the STBC-only system in terms of SER,especially at low signal-to-noise ratios.Therefore, the precoder design for STBC could improve the SER performance of relay network effectively.