A Tutorial on Low Density Parity-Check Codes

− Low density parity-check codes are one of the hottest topics in coding theory nowadays. Equipped with very fast encoding and decoding algorithms (probabilistically,) LDPC are very attractive both theoretically and practically. In this paper, I present a throughout view of LDPC. I discuss in detail LDPC’s popular decoding algorithm: belief propagation. I also present some noticeable encoding algorithms including Richardson and Urbanke’s lower triangular modification that gives rise to a linear encoding time. I show that irregular LDPC perform better than regular LDPC thus are more desirable.