Construction of M-PSK trellis codes and performance analysis over fading channels

By using derived analytical bounds, the authors show that to minimize the error probability of MPSK TCM (trellis coded modulation) codes on fading channels the free Euclidean distance should be maximized for large ECL (effective code length) codes. For short ECLs, however, the ECL and the minimum PD (product distance) are used as the design criteria to obtain better codes than corresponding Ungerboeck codes. By using a simulation method, it is shown that the code performance is extremely sensitive to interleaving depths and that the penalty due to nonideal interleaving is high. The results also indicate much less sensitivity of trellis codes to decoding decision depths on fading channels than on Gaussian channels, allowing higher interleaving degrees on delay-constrained communication systems. Error performance bounds are derived for MPSK trellis codes over Gaussian and fading channels in the presence of phase noise. Coherent demodulation combined with the transparent tone in band technique (TTIB) for phase recovery is evaluated