An adaptive multiuser detector for DS-CDMA systems in multipath fading channels

摘要

In this paper, we investigate the performance of an adaptive multistage detection scheme for direct-sequence code-division multiple-access (DS-CDMA) systems. The first stage consists of an adaptive multiuser detector which is based on the linear constrained minimum variance (LCMV) criterion. The interference cancellation (IC) occurs in the second stage. The performance of the iterative receiver over both flat and frequency-selective fading channels is investigated and compared to the single-user bound. In all cases, and under heavy system loads with near-far problems, the iterative receiver is shown to offer substantial performance improvement and large gain in user-capacity relative to the standard LCMV. In flat-fading channels, our results show that the performance of the iterative detector is very close to the single-user bound. For the frequency-selective channel, this performance is noted to be in the order of 1 dB far from the single-user bound.