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

In this paper 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 in this paper 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 slided 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.