LDPC Codec Research And Performance Simulation

Low density parity check codes (Low Density Parity Check Codes, referred to as LDPCcode) with low complexity iterative decoding algorithm and approximation of the channelcapacity and become one of the best coding technology, because of its strong error correctingability and simple decoder structure in deep space exploration, satellite communications andother fields the application of. The LDPC code has the following advantages:(1) does notneed the interleaving depth obtained very good error rate performance;(2) the frame error rateperformance is better;(3) the error floor is greatly reduced;(4) decoding is not based on grid;(5) parallel decoding, the decoding delay is small.Low density parity check code is a kind of special linear block code, its particularity inthe sparsity of the parity check matrix, which shows better performance of the root cause.Since the LDPC code is a new awareness, how to construct a practical good code, how torealize the LDPC code efficient encoding and decoding technology gradually becomes a hotpoint of study LDPC code theory. LDPC codes can be divided into random LDPC codes andQC-LDPC codes as an important subclass of LDPC codes, its most prominent feature is aquasi form of the cycle, without occupying large storage space, only need to store the matrix,in addition, quasi cyclic characteristic make the easy realization of efficient low complexityencoding and decoding, can be easily implemented in hardware, so the study of cyclic LDPCcode alignment has important theory valueThis paper summarizes the coding and decoding methods of check matrix constructionmethod and LDPC code in the analysis of the basic definition, classification of LDPC codes isintroduced based on the system. Including the construction method, the check matrixencoding method, decoding method is introduced and the simulation with MATLAB,expounds the contents. In the actual design, the random construction rate parity check matrixof1/2as example, structure of the parity check matrix is described, complete the coding part.And then use BP algorithm to decode the. Finally the simulation of LDPC codes in theMATLAB environment, and comparison of different a, the impact on system performance ofB parameters and different code length.