一种优化CDMA系统并行干扰抵消权值算法

研究了多径衰落信道下CDMA系统中多级部分并行干扰抵消器问题,通过对残余干扰方差分析推导了存在信道估计误差时的最优干扰抵消权值表达式,提出了适用于多速率CDMA系统的信道估计辅助的部分并行干扰抵消器。通过理论分析和仿真实验证实了所提出的方案比使用最佳固定权值的部分并行干扰抵消器性能优越,在BER为0.01时,使部分并行干扰抵消器第二级仅比使用理想信道估计再造干扰的部分并行干扰抵消器第一级的性能差1.5 dB。

An Algorithm of Optimizing Weight for Parallel Interference Cancellation in CDMA Systems

This paper studies multistage partial parallel interference cancellation for CDMA systems over multipath fading channels. By analysis of the variance of residual interference, we derive an expression determining the optimal interference cancellation weight in the event of channel estimation error and propose a channel-estimator-aided partial parallel interference cancellation applicable to multi-rate CDMA systems. The simulation results verify the reasonable assumption that the proposed partial parallel interference cancellation has performance better than partial parallel interference cancellation with freewill constant weight. It is indicated that, at a BER of 0.01, the performance loss of the proposed PPIC stage 2 is only 1.5 dB, compared to partial parallel interference cancellation with channel-known interference of one stage.