Soft-decision detection for phase/frequency modulation with symbol-wise Viterbi decoding

This paper proposes a simple soft-decision generation method for phase/frequency modulation with a binary convolutional code and symbol-wise Viterbi decoding. Taking symbol mapping of the phase/frequency modulation into account, the proposed method uses the in-phase and quadrature components of a received symbol in the frequency domain as likelihood information for the candidate symbols. Simulation results show that the proposed method improves the decoding performance to good effect, and that the phase/frequency modulation using the proposed method is a promising alternative to M-FSK.