Discussion Of LDPC In MIMO System

Low-Density Parity-Check (LDPC) code is a class of error-correcting codes which have limited capacity. By using low complexity algorithms based on belief propagation, LDPC codes can get near Shannon limit decoding performance. For long code lengths, LDPC codes can even outperform Turbo codes. Due to the advantages of LDPC codes, their applications in reliable communications have been paid great attentions to and become one of the most attractive fields in channel coding community. Now, the application of LDPC has been put on the agenda. Wireless MIMO, another hot technology in the NGN, is regarded as one of the key technologies that realize the high-speed broadband wireless Internet access networks in the future.Based on the encoding and decoding theories of LDPC and the main coding schemes of MIMO system, the thesis combines the LDPC with the MIMO system to get better performance. The factors which influence the LDPC-MIMO combined system are deeply analyzed. In order to get better performance of decoding, it uses the information from the Space-Time coding block in the decoding of LDPC by the factor posterior-probability. At last, a new encoding method of LDPC is attempted to construct the parity check matrix from the point of view of primitive. That is to say, the matrix is made use of primitive polynomial and the technology of row-column decomposition. Matlab is implemented to do a number of computer-aided simulations for getting the performance of systems.It is a long way to put the LDPC-MIMO combined system into application, although LDPC-MIMO system is good, but there are many problems which have not been solved. At the end of this dissertation, it summarizes all the work I have done, and shows what I should do in the future. Such as the proper code structure that can be implemented more easily in hardware, liner encoding problem, the information exchange between the LDPC and MIMO system and so on. An encoding scheme of primitive LDPC with a low-complication and good performance is worth to research.