A Low-Complexity Sequence Detection Algorithm Based on Laurent Decomposition for Multi-h Continuous Phase Modulation

Aiming at the deficiency of the present algorithms of demodulation for multi-h continuous phase modulation (CPM), such as large amount of computation and engineering issues to achieve high degree of difficulty, a low-complexity sequence detection algorithm based on Laurent decomposition for multi-h continuous phase modulation signals is presented. Two approximate processes are used to reduce the number of matched filters and the number of states in Viterbi decoder, combined with reduced state sequence detection (RSSD) algorithm with decision feedback to further reduce the number of states in the back-end state trellis processing. To estimate the performance of the proposed receiver, this algorithm is applied to a practical application of the multi-h modulation scheme. Simulation results show the number of trellis states is reduced from 32 to 4, and the number of matched filters is reduced from 8 to 2 by using the algorithm. However, only 0.9 dB performance loss is caused compared with the corresponding traditional optimum maximum likelihood sequence detection (MLSD) algorithm in this instance. So we can see that the algorithm can reduce the computational complexity of the multi-h continuous phase modulation receiver very efficiently, and it is much easier to implement and more suitable for practical application.