Suboptimum soft-output detection algorithms for coded multiuser systems

In this paper, me consider coded asynchronous multiuser signals in an addit ive white Gaussian noise channel. Since optimum joint multiuser detection ( MUD) and forward error correction (FEC) decoding is characterized with a ve ry high computational complexity, me consider disjoint MUD and FEC decoding , The optimum disjoint multiuser detector is the soft-output maximum a post eriori detector that provides sequences of a posteriori probabilities to th e corresponding FEC decoders. It involves backward and forward recursions r esulting in high complexity and processing delay. In this paper, me conside r several suboptimum soft-output disjoint multiuser detectors that involve only forward recursions and have reduced complexity and delay.