One-Step Backtracking Algorithm Based on Viterbi Algorithm in GMSK Demodulation

Viterbi algorithm is a commonly used algorithm for Gaussian filtered minimum frequency shift keying (GMSK) demodulation, but there exist some problems such as large delay, high overhead, and data overflow in the hardware implementation. Aiming at the problems of delay and overhead, we propose a novel update rule to optimize the stored transfer-state information table and realize one-step backtracking in this paper. It also ensures the realization of pipeline operation, reduces demodulation delay, and saves hardware resources. Furthermore, we adopt combinational logic to perform pre-decision, which not only satisfies the timing requirements, but also achieves the anti-overflow. The hardware implementation results demonstrate the feasibility and correctness of the design.