A Fully-Unrolled LDPC Decoder Based on Quantized Message Passing

TL;DR

This paper introduces a quantized message passing algorithm for LDPC decoders that uses look-up tables to maximize mutual information, enabling a fully unrolled hardware implementation with reduced message bit-width while maintaining error rate performance.

Contribution

It presents a novel finite alphabet message passing algorithm with look-up tables for LDPC decoding, achieving hardware efficiency without sacrificing error correction performance.

Findings

Decoder matches conventional error rate performance

Reduced message bit-width improves hardware efficiency

Fully unrolled hardware architecture demonstrated

Abstract

In this paper, we propose a finite alphabet message passing algorithm for LDPC codes that replaces the standard min-sum variable node update rule by a mapping based on generic look-up tables. This mapping is designed in a way that maximizes the mutual information between the decoder messages and the codeword bits. We show that our decoder can deliver the same error rate performance as the conventional decoder with a much smaller message bit-width. Finally, we use the proposed algorithm to design a fully unrolled LDPC decoder hardware architecture.