Distributed Space–Time Coded CPM System with AF Scheme

Since continuous phase modulation (CPM) has high energy and spectral efficiency, distributed space–time coded CPM (DSTC CPM) systems can significantly reduce the energy consumption at the transmitter as compared to its counterpart with linear modulations. However, it is still an important issue to investigate optimal power allocation between the transmitter and the relays in DSTC CPM systems. In this paper, four protocols are summarized for amplify-and-forward scheme in DSTC CPM systems; then, channel matrices are analysed according to these protocols. Furthermore, pairwise probability is computed in a new form of the Laurent expression based on analysis of CPM signal matrix. Moreover, tight upper bounds for the frame error rate are derived for these protocols. Finally, simulations are presented to verify our analysis.