Study On Technique Of Space-time Concatenated Codes Based On LDPC

This dissertation research the architecture and decoding algorithm of space-time concatenated codes based on LDPC code.On the basis of introducing the structure of the MIMO communication system, LDPC code the space-time coding and the various space-time concatenated code scheme are analyzed in detail. The scheme of LDPC V-BLAST concatenated code is designed and the decoding algorithm is presented.In order to reduce complexity of space-time concatenated codes and improve the encoding efficiency, this dissertation chooses the LDPC code as the error-correcting code and the V-BLAST code as the space-time code; The BP algorithm combined with group shuffle schedule is used in the internal iterative decoder and MMSE is used in the external iterative decoder. Because the information of check nodes is reserved for the initial value of the next iteration, the number of internal iterations exactly reduce.Error correction coding can provide a temporal diversity to combat wireless channel distortion while the MIMO system can provide spatial diversity to improve the channel capacity. Therefore, high-speed and reliable wireless can be achieved with the space-time concatenated codes. With the clear target, both the structure of the MIMO system and the characteristics of the wireless channel are introduced. And several MIMO channel capacity computational methods are presented. Then, the encoding and decoding methods of LDPC have been discussed, including some popular sub-optimal BP algorithms. The dissertation focuses on some space-time concatenated codes and the corresponding decoding methods. Finally, the VBLAST coding system based on the LDPC code is presented and an improved iterative decoding algorithm is analyzed and simulated.The simulation shows that the V-BLAST cascade code based on LDPC code can achieve a good balance of complexity and performance, which can meet the practical application of engineering.