基于Nakagami衰落的分集合并系统性能分析

Performance Analysis of Diversity System over Nakagami Fading Channels

分集技术可有效提高无线通信系统抗衰落性能,通过将Nakagami衰落下的分集系统等效为单输入单输出系统,推导获得了选择合并(Selection combining,SC)、等增益合并(Equal gain combining,EGC)和最大比合并(Maximal ratio combining,MRC)3种方式下系统的输出信噪比和中断概率等性能表达式,并提出一种基于改进的Nakagami分集信道舍弃法模型用于数值仿真与验证。仿真结果表明,理论表达式结果与仿真值非常吻合,可用于辅助瑞利、莱斯和Nakagami等多种信道衰落下分集系统的参数选择、算法设计和性能评估。

Diversity combining is an effective technique to combat signal fading and improve the perform- ance of wireless communication system significantly. The diversity system over Nakagami fading chan- nels is equivalent as a single input and single output （SISO） system. Then, the expressions of system parameter such as signal-to-noise ratio （SNR） distribution and outage probability are derived for selec- tion combining （SC）, equal gain combining （EGC） and maximal ratio combining （MRC） schemes under Nakagami fading channels. A modified Nakagami fading model based on rejection method is also presen- ted to numerical simulation and validation. Numerical simulation results show that the theoretical re- sults match the simulation results very well, which is helpful for parameter selection, algorithm design and performance evaluation of diversity system over various fading such as Rayleigh, Rice and Nakaga- mi.