Noncoherent continuous phase frequency-shift keying with trellis-coded modulation

In this paper, we examine the design of a continuous phase frequency-shift keying (CPFSK) system with trellis-coded modulation (TCM) when the detection is noncoherent. A multi-symbol correlation method is used to provide improved branch metrics for the Viterbi decoder. A suboptimal detector structure is then created that provides essentially identical results with a decrease in complexity. Simulation results show that for adequate signal-to-noise ratios (SNRs), the noncoherent CPFSK-TCM system can out-perform a non-coded, noncoherent CPFSK system at the same bit rate and bandwidth. Work to design optimal codes is continuing.