Protograph-Based LDPC Code Design for Probabilistic Shaping with On-Off Keying

TL;DR

This paper develops protograph-based LDPC codes tailored for probabilistic shaping with On-Off Keying to enhance power efficiency in AWGN channels, especially at low SNRs, demonstrating significant performance gains.

Contribution

It introduces a novel transmitter architecture for probabilistic shaping and designs specialized LDPC codes that outperform standard schemes in power efficiency.

Findings

Achieves 1.1 dB gain over standard codes at 0.25 bits/channel use

Proposes a time-sharing based probabilistic shaping method

Demonstrates improved power efficiency at low SNRs

Abstract

This work investigates protograph-based LDPC codes for the AWGN channel with OOK modulation. A non-uniform distribution of the OOK modulation symbols is considered to improve the power efficiency especially for low SNRs. To this end, a specific transmitter architecture based on time sharing is proposed that allows probabilistic shaping of (some) OOK modulation symbols. Tailored protograph-based LDPC code designs outperform standard schemes with uniform signaling and off-the-shelf codes by 1.1 dB for a transmission rate of 0.25 bits/channel use.