一种改进的差分空时协同分集方案及误码性能分析

The SER Performance Analysis of an Improved Differential Cooperative Diversity System

提出了一种分布式差分空时分集方案,通过对差分编码方式的改进,可使用多种星座形状来进行调制。在采用了QAM星座调制时,比传统的PSK调制具有更好的性能,可以改善无线网络中的能量效率。在不考虑协同节点间误码的情况下,分析和推导了平坦衰落瑞利信道下该方案的SER性能上限的表达式。仿真结果表明采用QAM调制下的DSTBC性能优于PSK调制下的DSTBC。同时在慢衰落的条件下,仿真结果和理论分析的结果吻合较好,说明了方案的有效性。

In this paper, we present a differential space-time codes systemby using arbitrary constellation modulation and improving differential coding. We use QAM modulation to get better performance than the traditional PSK modulation, which can improve the energy-efficiency in wireless networks, A close form expression for signal error rate（SER） of the proposed system is derived in flat fading Rayleigh channels without considering the errors of information between local nodes. Numerical results show that performance of the proposed QAM-DSTBC is better than that of the traditional PSK-DSTBC. Futhermore, the simulation results in slow fading channels verify the validity of the theoretical results.