Reduced state joint iterative equalization and multiuser detection in dispersive CDMA channels

Communications in dispersive multiuser CDMA channels suffer from both intersymbol and multiuser interference. MAP equalization and multiuser detection with error control coding can be used to combat this interference and achieve optimal performance. For reducing the high computation complexity of the optimal algorithm, a reduced-state trellis search, which exploits decision feedback from the decoder is proposed. Simulations show that this low complexity algorithm can obtain near-optimal performance under medium signal-to-noise ratio and has larger system load capacity than parallel interference cancellation.