An efficient architecture for iterative soft reliability-based majority-logic non-binary LDPC decoding

Non-binary low-density parity-check (NB-LDPC) codes have better error-correcting performance than their binary counterparts at the cost of higher decoding complexity when the code length is moderate. Compared to other NB-LDPC decoding algorithms, the iterative reliability-based majority-logic decoding can achieve better performance-complexity tradeoff. In this paper, an efficient partial-parallel shift-message decoder architecture is proposed for cyclic NB-LDPC codes based on the iterative soft reliability-based majority-logic decoding (ISRB-MLGD) algorithm. The message shifting is implemented by memories concatenated with variable node units to reduce the area. Although the accumulated soft reliabilities in the ISRB algorithm require longer word length, and accordingly longer critical path and larger memory, the decoder architecture and control logic can be simplified. Particularly, the check node units are modified so that the message switching network can be eliminated. Compared to the iterative hard reliability-based decoder for a (255, 175) NB-LDPC code over GF(2⁸), the proposed ISRB decoder can achieve around 0.8dB coding gain with less than three times hardware complexity.