Iterative multiuser receiver utilizing soft decoding information

In this paper we propose a novel receiver structure that utilizes the soft information provided by the channel decoder in the multiuser detection. This receiver structure is based on a single-user version of the uncoded maximum a priori criterion. We derive the optimal multiuser likelihood calculation algorithm for this structure. In addition, suboptimal algorithms are proposed that are based on interference cancellation. Numerical simulations are reported which indicate that these suboptimal algorithms have a close-to-optimal coded BER performance even in the presence of high-power interferers