MP&A Mixed Decoding Algorithm for LDPC Codes

Because the message passing (MP) method is suboptimum and optimum solutions are not guaranteed, we present a hybrid decoding method by combing the MP and the A* methods. We first make comparison between the MP and A* method and then show their combined performance. Using the hybrid structure, its decoding gain is the same as that of A* method. Moreover, decoding complexity is slightly greater than that of MP one. For codeword length 96 bits and coding rate 1/2 and BER = 10-5 , the hybrid structure outperforms 1.4 dB decoding gain than the MP method. This improvement only required 1% received sequences to be transferred to A* decoding block. Our newly designed hybrid structure can solve both of the high decoding gain and low decoding complexity while it has the ability to yield the optimum solution.