Trellis-coded 16-PSK and 16-QAM modulation for satellite communications

The performance of trellis-coded 16-PSK and 16-QAM modulation schemes is considered in the framework of a channel model which reasonably approximates the Intelsat SCPC system. The main goal of the research was to investigate whether the efficiency of trellis-coded modulation (TCM) schemes and their saving in transmitted power could be maintained in a system environment dominated by interference more than by additive white Gaussian noise. A second goal was to compare the performance of signals with constant envelope, like 16-PSK, with that of signals allowing variations in amplitude, like 16-QAM. A method for performance evaluation leading to an estimate of the asymptotic power gain of the modulation systems is given. The channel model and the method are applied to the analysis of coded 16-PSK and 16-QAM.<>