Two-stage detection of coded CDMA systems and a novel interleaving scheme

Code division multiple access (CDMA) systems have become a serious contender in the technology market for wireless communications systems. Conventional or single-user detection so far has been preferred in CDMA receivers despite many shortcomings due to its simplicity. Multiuser detectors on the other hand can offer dramatically higher capacity at the expense of some increase in complexity. We consider the performance improvements afforded by multiuser detection of coded CDMA systems. We focus on two-stage detection schemes and particularly the two-stage detector with a conventional first stage and show that it is a robust detector under different operating conditions. We then describe an alternative receiver structure for two-stage detectors in coded systems, which when combined with an independent user interleaving scheme gives significant performance improvements.