New reduced complexity turbo-detector for highly selective long delay spread ISI channels: a solution for 4G mobile systems?

We investigate a new turbo-detector scheme. The data detection part of the iterative receiver is based on variants of full-state SOVE (soft-output Viterbi estimation) and SOVA (soft-output Viterbi algorithm) intersymbol interference (ISI) decoders. Those variants employ reduced-state techniques combined with generalized per-survivor processing. They offer a very good trade-off between performance and complexity even with long delay channels. Monte-Carlo simulation results in various severe propagation environments show that the proposed sub-optimal turbo-detector is usually 1.8 to 3 dB away from the optimal BCJR (Bahl-Cocke-Jelinek-Raviv) based one with a significant computational complexity reduction. Hence it appears as a possible candidate for future mobile radio communications with high bit rate transmission