Design of non binary quasi-cyclic LDPC codes based on RA encoding

A method to construct non binary QC-LDPC codes is proposed based on RA encoding with reducing encoding complexity. It is just to compute parity check symbols according to check equations or parity check matrix, and it´s not necessary to apply a generator matrix to the encoder, which greatly reduced encoding complexity. Also, the quasi-cyclic structure of parity check matrix makes it possible to realize parallel decoding with very low complexity. Simulation results show that this class QC-LDPC codes without small loop outperforms random LDPC codes both in complexity and performance with middle length and it is very suitable for implementation.