An iterative multiuser receiver using partial parallel interference cancellation for turbo-coded DS-CDMA systems
Kuo-Ming Wu, Chin-Liang Wang · 2002
A low-complexity multiuser receiver for turbo-coded DS-CDMA systems is presented to perform jointly iterative multiuser detection and turbo decoding. The proposed approach consists of a new multistage partial parallel interference cancellation (NPPIC) detector and K single-user turbo decoders, where K is the number of active CDMA users. The NPPIC detector is derived based on the single-user maximum a posteriori criterion and has a similar simple structure to the conventional partial parallel interference cancellation scheme presented by Divsalar et al. (see IEEE Trans. Commun., vol.46, p.258-268, Feb. 1998). A prominent feature of this detector is that it delivers interference-cancelled soft outputs to the turbo decoders and utilizes the soft information from the turbo decoders' output. Extensive computer simulations demonstrate that the cooperation between NPPIC and turbo decoding offers significant performance gain over the traditional non-iterative receivers and performs comparably to some existing iterative schemes of much higher complexity.