CDMA系统动态子空间跟踪算法

Dynamic Subspace Tracking Method for CDMA System

基于子空间分析的 CDMA多用户检测算法是近期线性多用户检测算法中研究得比较多的一类 ,其基础——子空间跟踪领域长久以来也有大量的研究结果 ,然而适用于 CDMA系统且性能较高、运算量低的算法并不多见。本文针对 CDMA系统的用户数目发生变化 ,从而导致信号子空间维数变化的情况进行分析 ,提出一种基于基旋转的动态子空间跟踪算法。仿真结果表明 ,该算法能迅速地跟踪维数变化了的信号子空间 ,从而提高基于该跟踪结果的 CDMA多用户检测算法的性能。

Subspace based Multiuser Detection is a hot direction in the field of linear multiuser detection method, and there are also lots of research results and algorithms in subspace tracking, but not much methods are suitable for CDMA system with high performance and computational efficiency. In this paper we focus at the point that number of users is changed, which cause the change of signal subspace's rank, and propose a dynamic subspace tracking method based on the idea of basis rotation. Simulation shows that new algorithm can quickly follow the dynamic signal subspace, which in turn enhances the performance of those CDMA MUD methods which are based on the subspace tracking result.