Time-frequency decision-driven multiuser detectors over fast-fading multipath channels for synchronous DS-CDMA systems

Abstract

RAKE receivers suffer degradation in performance under fast fading due to errors in channel state estimation. The wide-sense stationary uncorrelated scatterer channel model tends itself to time-frequency canonical representation, and provides additional diversity in the frequency axis. That is, the joint multipath-Doppler diversity model enables the development of nonlinear decision-driven time-frequency multiuser detectors based on successive interference cancellation and multistage interference cancellation ideas. Simulation results demonstrate that the proposed nonlinear decision-driven time-frequency multiuser detectors promise substantially improved bit-error-rate performance compared to previously proposed time-frequency multiuser detectors while exhibiting strong resistance to the near-far effect.