判决反馈自适应滤波应用于CDMA系统中的单频干扰抑制

Adaptive Filter Using Decision-Feedback Applied to Single Frequency Interference Suppression in CDMA Systems

针对扩频接收机中窄带干扰抑制中已有结构和算法的优缺点，提出一种在滤波器输入和权值修正中均利用判决值的判决反馈方案，并对常规、采用软判决和采用硬判决三种情况的单边预测型结构和常规最小均方误差（ＬＭＳ）算法、可变步长ＬＭＳ（ＶＳＳ）算法和变步长变动量因子ＬＭＳ（ＶＳＶＭＳ）算法三种算法进行了计算机模拟。结果表明，此判决反馈方案对抑制单频干扰在性能上比已有结构有明显改进，且软判决比硬判决性能略优，算法以ＶＳＳ性能最佳。

According to the characteristics of the existing narrowband interference suppression filter structures and algorithms,a kind of scheme using decision-feedback both in filter reference input and error signal is promoted. Computer simulations are made with three types of single side prediction filter structure (including conventional,using soft decision and using hard decision) and three normalized algorithms (including conventional LMS,VSS,VSVMS). It is shown that significant improvement can be obtained and soft decision is slightly better than hard decision from the results and VSS algorithm can get the best performance.