Performance of Multiuser Decision-Feedback Detector for Flat Rayleigh Fading Synchronous CDMA Channels

We consider interference rejection for synchronous CDMA frequency non-selective channels using multiuser decision-feedback detector. The average error rate of the ideal two-user decision feedback detector is derived in a closed form and the asymptotic multiuser efficiency is proved to be unity. The effect of error propagation on the actual decision-feedback detectors is investigated through simulation. Comparison among the decision-feedback detector, the conventional detector, and the linear decorrelating detector is undertaken for several two-user and four-user bandwidth-efficient synchronous CDMA flat Rayleigh fading channels. We find that the decision-feedback detector outperforms other detectors and its average bit error rate is close to the single user bound under diverse: channel conditions.