Nakagami衰落上DE-QPSK在联合收发分集下的性能分析

利用高斯Q函数的高阶次幂在最大比合并（MRC）分集接收瑞利衰落信道上统计平均的结果，推导了Nakagami 衰落信道上采用组合发射选择合并（SC）/接收 MRC 天线分集的相干检测差分编码四相相移键控（DE-QPSK）的平均误符号率（ASER）精确表达式。利用高斯Q函数的近似表达式和矩生成函数（MGF）方法，推导了Nakagami衰落信道上采用组合SC/MRC天线分集的相干检测DE-QPSK 的ASER近似表达式。通过数值计算和仿真，验证了DE-QPSK的ASER精确表达式的正确性以及近似表达式的准确性。利用精确表达式和近似表达式可研究收发天线数目和衰落参数对DE-QPSK的ASER性能的影响，为实际SC/MRC天线分集方案的设计提供了理论指导。

Performance Analysis of DE-QPSK with Joint Transmit and Receive Diversity in Nakagami Fading

By using the statistical average results of higher-order powers of Gaussian Q-function in multi-branch diversity reception with maximum ratio combining（MRC）in Rayleigh fading channel，exact closed-form for the average symbol error rate（ASER）of differentially encoded quadri-phase shift keying（DE-QPSK）using coherent detection with transmit selection combining（SC）and receive MRC（SC/MRC）in Nakagami fading channels was derived.Approximate closed-form for the ASER of DE-QPSK with SC/MRC in Nakagami fading channels was derived by using the approximate expression of Gaussian Q-function and moment generating function based analysis approach.Numerical and simulation results show that the theoretical analysis of the ASER of DE-QPSK is exact and the approximate closed-form for the ASER of DE-QPSK is accurate.The above results can be used to design SC/MRC antenna diversity systems with DE-QPSK.