Noncoherent coded continuous phase modulation

Continuous phase modulation (CPM) systems for noncoherent coded transmission are proposed and analyzed. Specifically, the application of a feedback–free modulator is regarded. For demodulation, a receiver structure which requires only two or three linear filters is considered. For decoding, noncoherent sequence estimation (NSE) with Viterbi decoding and per–survivor processing is applied. Noteworthy, in our approach the problems of low–complexity filtering and reduced–state decoding can be treated separately. Since we give a recursive formula for the phase reference symbol necessary for NSE metric calculation, computational effort is further decreased. Overall, in terms of complexity, the proposed noncoherent receiver provides significant advantages over recently presented approaches. The high performance of the novel noncoherent CPM system is confirmed by simulation results.