Bit-Metric Decoding of Non-Binary LDPC Codes with Probabilistic Amplitude Shaping

TL;DR

This paper introduces a flexible bit-metric decoding approach for non-binary LDPC codes combined with probabilistic amplitude shaping, maintaining performance without requiring matching field and constellation sizes.

Contribution

It proposes a novel bit-metric decoding method that enhances flexibility in non-binary LDPC coding with PAS without performance loss.

Findings

Bit-metric decoding matches symbol-metric decoding performance with PAS.

Increased flexibility by not requiring matching field and constellation sizes.

Maintains high information rates and low error thresholds.

Abstract

A new approach for combining non-binary low-density parity-check (NB-LDPC) codes with higher-order modulation and probabilistic amplitude shaping (PAS) is presented. Instead of symbol-metric decoding (SMD), a bit-metric decoder (BMD) is used so that matching the field order of the non-binary code to the constellation size is not needed, which increases the flexibility of the coding scheme. Information rates, density evolution thresholds and finite-length simulations show that the flexibility comes at no loss of performance if PAS is used.