Suboptimum detection of trellis-coded CPM for transmission on bandwidth- and power-limited channels

The authors consider a communication scheme based on continuous phase modulated (CPM) signals used in conjunction with trellis-coded modulation (TCM) for transmission over a channel affected by Gaussian noise and fading. This scheme provides a power saving due to the coding gain of TCM and a reduced bandwidth occupancy due to the features of CPM signals. Moreover, CPM provides constant-envelope signals. To keep the complexity of the receiver manageable and to be able to use interleaving/deinterleaving techniques to spread the fade bursts, suboptimal detection schemes must be used. Two such schemes, based on coherent and noncoherent detection of CPM, are considered. Their performance is evaluated by computing the computational cutoff rate of the discrete channel generated by CPM