基于频域分量最大比合并的多天线信号合成算法性能分析

Equalizer Performance Analysis of Frequency-Domain Max-Ratio Combining Algorithm

通信信道的频率选择性衰落特性和信道噪声都会严重影响信号的接收质量。基于频域分量最大比合并的多天线信号合成算法(FMRC)对多路信号在频域加权合成,能够提高合成信号信噪比,实现频率选择性衰落信道下低信噪比信号的有效接收。文章针对该算法的理论性能,对合成信号均衡处理,分别推导了线性均衡器和判决反馈均衡器输出均方误差的理论表达式;证明了该算法与空间分集均衡器(SDE)在性能上的等价性。仿真实验表明,FMRC与SDE性能是一致的,但是在高信噪比下,当单路信道存在深衰落时,FMRC算法通过合成能够改善单路信道的深衰落特性,均衡器输出均方误差性能较SDE更优。

The frequency selective fading characteristics and the noise from transmission channels seriously affect signal reception. The frequency-domain max-ratio combining （FMRC） algorithm weights the antenna signals in frequency domain and improves the signal-to-noise ratio （SNR）, which effectively impletements the reception of low-SNR signals in frequency selective fading chan- nels. This paper equalizes the output combined signal in terms of the theoretical performance of FM- RC, and calculates the theoretical mean square error （MSE） performace of eighter linear equalizer or decision-feedback equalizer. The MSE performance of the FMRC algorithm is same as that of the optimal combing linear equalizer （SDE-LE） or the optimal combing feedback equalizer （SDE- DFE）. Simulation results show that the MSE performance of the FMRC algorithm equals to that of SDE. However, when the channels are deeply faded and the SNR is high, the FMRC algorithm can overcome the fading characteristics by combining to some extent, thus the MSE performance outper- forms that of SDE.