Iterative multi-user detection and decoding for turbo-coded DS-CDMA systems

In this paper we consider turbo-coded multi-user DS-CDMA communications. We first present a new scheme for Soft-Input Soft-Output multi-user detection. Our method provides the Maximum A Posteriori estimate for each user bit together with its fiability in the form of an extrinsic information. It is based on the stack algorithm over the tree diagram of the CDMA channel. The Soft-Input Soft-Output multi-user detector is then associated to a bank of turbo-decoders in a global turbo loop to perform iteratively multi-user detection and turbo-decoding. Simulation results show the high efficiency of the proposed method.