频率选择性衰落信道中的RAKE合并接收方案

RAKE Combining Receiver in Frequency Selective Fading Channels

针对非扩频系统很难实现多径分集接收的问题,通过判决反馈IIR(DF-IIR)均衡器得到对发送数据的估计,并根据该初始估计重构所有多径信号,再将接收信号中的主径和各多径分量区分开,最后将各分量按照最大比的方式合并以及解调判决,从而实现RAKE合并接收。DF-IIR均衡器可以完全消除噪声累积的现象,然而判决反馈同时会产生误差传播的问题,多径合并可以显著提高信噪比,从而抑制误差传播问题。仿真结果表明新算法可以取得明显的效果。

Aiming at the multipath diversity reception in non-spectrum-spreading system,a RAKE combining receiver is presented in this paper.The estimate of the transmitted data is obtained by the IIR（infinite impulse response） equalizer with decision feedback（DF） structure,and each multipath signal can be resumed by this initial solution.Then the multipath elements in the received signal are obtained,and the components are combined together using maximal ratio combining（MRC） before the final decision,so RAKE combining receiver is accomplished.The cumulated round off noise phenomenon is eliminated by DF-IIR,however,error propagation exists in the decision directed filter.While the signal-to-noise ratio（SNR） can be increased evidently after MRC,the error propagation problem is depressed dramatically in the combining receiver.Simulations show that the proposed algorithm can achieve the performance advantages effectively.