基于变步长LMS的自适应匹配算法

Adaptive Matched Demodulation Algorithm Based on LMS with Variable Step Size

基于最小均方误差准则,提出了一种用于抑制异步直扩CDMA系统中的多址干扰的变步长LMS自适应匹配算法。计算机仿真结果表明,基于该类算法的自适应解扩多用户检测器无须知道任何用户的地址码,具有良好的抗“远近效应”能力,与类似的变步长LMS算法相比,该算法具有更低的误码率、更快的收敛速度和跟踪速度,特别是其控制参数在信道参数发生变化时不需重新调整,同时具有广泛的应用前景。

Based on Minimum-Mean-Square-Error(MMSE) criterion, a kind of LMS algorithm with variable stop size is proposed to suppress Multi-Access Interference (MAI) in asynchronous DS-CDMA system. Compare with similar variable step size LMS algorithm, computer simulation results show that the kind of detector is insensitive to the near-far effect and its structure is very simple. At the same time, it has lower bit error rate and faster speed of convergence and tracking without increasing computational complexity. In particular, the controlling parameters of proposed algorithm are not required to re-adjust, even if the channel parameter changes. So it can be widely used.