Coding And Application Of Low Density Parity Check Codes

Proved to be near Shannon limit, Low-Density Parity-Check codes have bright prospects in all kinds of future communication systems. Because of their outstanding performance, good coding algorithm that has almost linear time complexity and decoding algorithm that could be carried out parallel, they have become one of the hottest topics in coding theory today.This paper does some research on the basic principles and applications of LDPC, and establishes foundation for future research. First of all, the paper introduces some basic principles of LDPC on the base of linear block code and sums up some familiar coding algorithms, and then gives two simple coding schemes according to specific configuration of the base parity check matrix given in the protocol of 802.11n. And then, the paper introduces hard-adjudged decoding algorithm and soft-adjudged decoding algorithm of Low-Density Parity-Check codes in detail, especially analyzes the most popular used decoding algorithm which is called sum product algorithm. After that, the paper presents the simulation system for LDPC and realization of the coding and decoding module. After that, this paper does some research on a particular Low-Density Parity-Check code- zigzag code and gives its coding and decoding algorithm. Finally, summarizes the broad application of Low-Density Parity-Check codes and analyses its applications in WLAN and future mobile communications. We simulate its performance in 802.11n system and compare it with convolution code. The simulation results indicate that Low-Density Parity-Check codes are much better than convolution code in all the working mode of 802.11n.