WSSUS衰落信道下的跟踪算法研究

Tracking algorithm for WSSUS fading channels

无线WSSUS衰落信道是时变信道,其信道参数随着时间的变化而变化。通常采用的经典跟踪算法(RLS算法)中的重要参数遗忘因子是固定值,这使得算法跟踪时变信道时性能无法保障。对均方误差(MSE)进行了分析,并在此基础上得到基于MSE梯度控制的可变遗忘因子VFF-RLS算法。仿真结果表明MSE分析结果正确;与经典算法相比较,VFF-RLS具有较小的MSE,更适合跟踪WSSUS信道。

This paper presents the Mean Square Error（MSE） analysis of Variable Forgetting Factor Recursive Least Square（VFF-RLS） algorithm for Wide-Sense Stationary Uncorrelated Scattering（WSSUS） fading channels.Unlike most of RLS analyses,this analysis takes the correlation of inverse of correlation matrix into account and hence yields an improved recursive formula for the MSE,which can be computed recursively with the information of the second order statistics of fading channels.The forgetting factor of RLS is varied by a gradient algorithm derived from the MSE analysis of VFF-RLS.Experimental results show that the VFF-RLS algorithm has smaller MSE than typical adaptive algorithms and better tracking ability.