DS/CDMA多用户检测盲自适应梯度算法的改进

The Improvement of Blind Adaptive Gradient Algorithms for Multiuser Detection in DS/CDMA Systems

本文在直接序列 /码分多址 (DS/CDMA)系统盲检测自适应梯度算法 (BAG)的基础上 ,提出了一种多用户检测盲自适应梯度算法的改进算法 (IBAG) .BAG算法包括自适应梯度算法 (TBAG)和时变自适应梯度算法 (TIBAG) ,TBAG算法的跟踪特性较好 ,但起始收敛特性不好 ;TIBAG算法的收敛特性较好 ,但跟踪特性较差 ,几乎不具备跟踪能力 .本改进算法结合了这两种自适应梯度算法的优点 ,在不增加算法复杂度的前提下 。

In this paper,based on blind adaptive gradient algorithm (BAG) for multiuser detection,an improved blind adaptive gradient algorithm (IBAG) for code aided suppression of multiple access interference (MAI) and narrow band interference (NBI) in direct sequence code division multiple access system is proposed.The blind adaptive gradient algorithm (BAG) has two types:tracking blind adaptive gradient algorithm (TBAG),which has the tracking ability,and time invariant blind adaptive gradient algorithm (TIBAG),which is applied in time invariant circumstances.TIBAG has good constringency but no tracking ability,while TBAG has good tracking ability but its SIR rises slowly at beginning.so,IBAG modifies TIBAG to make its SIR riss more quickly and to keep its tracking abilty as time goes on.The simulation results show that the IBAG has the similar computational complexity to BAG,but the tracking ability and convergence performance of the IBAG is much better than the BAG.