Rate-compatible QC-LDPC codes based on PEXIT.

An improved extension method based on protograph extrinsic information transfer (PEXIT) charts is proposed to design ratecompatible quasi-cyclic low-density parity-check (QC-LDPC) codes with more flexible rates and better performance. The masking matrix of the highest-rate code can first be constructed column by column to own the lowest decoding threshold. Then, an extension algorithm is proposed to obtain the masking matrices of lower-rate codes with flexible rates. Finally, the base matrices with small amount of short cycles are designed and the parity-check matrices of rate-compatible QC-LDPC codes are obtained through matrix extension. Simulations show that compared with the existing codes, the proposed codes have more flexible rates while achieving better performance. [ABSTRACT FROM AUTHOR]