Soft-detection phase precoding with MPSK-TCM for ISI channel

Trellis-coded modulation (TCM) concatenated with phase precoding is proposed to alleviate the effect of intersymbol interference (ISI) in frequency selective slow fading channels in wireless communications. Simulation results show that gains of 6.5 and 2.5 dB at a bit error rate (BER) of 10/sup -6/ are achieved by the hard detection method for 8PSK-TCM with four and eight state codes, respectively. The comparison is made with respect to a system employing post-equalization with a sub-optimum soft output equalizer and the same TCM schemes. Moreover, soft detection of the precoded signal is also carried out, which results in an additional gain of 4 dB. Finally, the simulation performance is compared with the analytical bound and they match quite well.