Noncoherent sequence detection of trellis-coded CPFSK with MRC diversity over fading channels

Soft-decision differential phase detection (SD-DPD) with Viterbi decoding is proposed for the detection of trellis-coded FSK signals over a fading channel. The soft detector detects the differential phase and chooses a subregion among a preselected set of subregions at the end of every interval. The effect of the number of subregions is studied. The proposed system is analysed over a Rician channel with maximum ratio combining diversity. Numerical results indicate that SD-DPD With Viterbi decoding performs significantly better than hard-decision decoding, and diversity improves performance. Numerical results also indicate that a suboptimal receiver that maintains the same set of metrics for all signal-to-noise ratios pet-forms close to optimal decoding.