Reduced-State Sequence Detection Based on Decision Feedback for Multi-h CPM

Multi-h Continuous Phase Modulation (Multi-h CPM) is often plagued by high receiver complexity which increases greatly with frequency pulse length L and dimension M. In order to reduce its complexity, a reduced-state sequence detection algorithm based on decision feedback in this paper is proposed for Multi-h CPM whose frequency pulse length L>1. Based on the conventional Viterbi algorithm, in the stage of sequence detection, the algorithm use a reduced state trellis combined with symbols feedback from the corresponding surviving path. In traditional signal model and PAM decomposition signal model, comparisons of BER performance between the proposed algorithm and MLSD are given respectively. In PAM decomposition signal model, the Frequency Pulse Truncation method is discussed particularly. The simulation results show that, with proper numbers of symbols feedback, a significant trellis states reduction can be achieved by the proposed algorithm at the cost of moderate loss in performance.