Spectrum, distance, and receiver complexity of encoded continuous phase modulation

A comparison of different classes of encoded continuous phase modulation (CPM) schemes is presented. In terms of joint power-bandwidth performance, it is found that coded eight-level systems are better than coded four-level systems and that partial-response signalling is better than full-response signalling. In general, the price paid for better performance is increased receiver complexity. Heuristic design rules have been used to find good codes for CPM. In most cases the coding gains found are identical to published results that were generated by exhaustive search, indicating that the choice of design rules is quite appropriate. In the present study bandwidth efficiency is considered from both the 99% and 99.9% power-bandwidth points of view. It is found that partial-response signalling is even more jointly power and bandwidth efficient for the latter than for the former bandwidth criterion