线性合并接收分集DFH系统性能分析

Performance Analysis of Differential Frequency Hopping System with Linear Combining Receive Diversity

为了提高差分跳频系统的抗噪声性能,提出了一种基于多接收天线的空间分集差分跳频系统,系统采用平方率检测线性合并准则进行合并接收。采用矩生成函数法分析了该系统在瑞利衰落信道下的抗噪声性能,得到了系统误符号率的闭式表达式。分析中考虑了各分集支路信号衰落参数及背景噪声不同的一般情况。数值和仿真结果表明,应用接收分集技术可以显著改善差分跳频系统的抗噪声性能,在误符号率为10-4时,采用双天线分集时即可使系统性能较无分集系统改善达约7 dB;性能改善量随天线数量的增多而增大,但改善幅度逐步降低;信噪比过低的分集支路应从分集中排除,否则可能使系统性能低于没有这些天线时的系统性能。

A differential frequency hopping（DFH） system utilizing receive diversity based on multiple receive antenna is proposed to improve the anti-noise performance of DFH system.Square-law detection linear combination rule is used in signal combination.Performance of this system under Rayleigh fading channel is analyzed with moment-generating function method.Symbol error rate（SER） in closed form is derived with the general case when fading parameters and background noise levels of signals of different branches are all non-identical considered.Numerical and simulation results show that space diversity using multiple receive antennas can improve the anti-noise performance of DFH system remarkably.The performance improvement is approximately 7 dB better than system without diversity at SER of 10-4 when double receive antenna applied.Performance improvement increases with the number of receive antennas but the further improvement extent decreases.Branches with much lower signal-to-noise ratio than other branches should be removed from combining otherwise system performance may be decreased comparing with systems without these branches.