Asynchronous multi-stage SIC detector for DS-CDMA systems over multipath fading channels

Abstract

A new interference cancellation (IC) scheme is proposed for the uplink of direct-sequence code division multiple access (DS-CDMA) systems communicating over mobile radio channels. The IC detector presented belongs to the subclass of multiuser detectors that employs a multi-stage successive interference cancellation (SIC), and the aim is to show that a low complexity detector can perform well in a mobile radio environment. The new multi-stage SIC scheme includes non-decision directed IC with a modified RAKE combiner to use the diversity in frequency-selective channels, and it works with a finite processing window sliding each iteration to process a new data symbol. The performance is evaluated with known asynchronous delays and channel parameters, in a multipath environment. The results show that the proposed detector is near-far resistant and the loss in performance compared to the single-user bound is small.