Impact of estimation errors on multiuser detection in CDMA

A majority of multiuser detectors for CDMA are based on coherent detection where carrier frequency, carrier phase, transmission delays and channel characteristics are assumed known at the receiver. In a real system, these parameters must however be estimated based on the received signal. In this paper we investigate the impact of delay and channel estimation errors on the performance of multi-stage successive interference cancellation and limited tree-search detection. The estimation errors are modelled as zero-mean Gaussian random variables with the variance being a measure of the accuracy of the estimation.