Parity Information Aided Iterative Multistage Decoding for Multilevel LDPC Codes

Iterative demodulation and decoding (ID) seeks to extract useful information from decoders by performing multiple successive demodulation and decoding iterations. Multistage decoding with iterative demodulation and decoding (MSD-ID) unites MSD and ID, in order to improve error probability performance for multilevel codes. This article evaluates MSD-ID performance for multilevel LDPC codes and compares to a proposed MSD-ID modification called \textit{parity information aided iterative multistage decoding} (PIA-MSD-ID), where parity-checking information obtained from the LDPC decoders is used to aid the whole decoding process. Rate distribution designs are made for MSD, MSD-ID and PIA-MSD-ID. The results show that PIA-MSD-ID achieves lower FER, in comparison to multistage decoding (MSD) and similar to MSD average complexity, for higher SNR.