On LDPC Codes for Gaussian Interference Channels

TL;DR

This paper designs and optimizes LDPC codes for the two-user Gaussian interference channel using the Han-Kobayashi strategy, achieving near-capacity performance in strong interference and nontrivial rates in weak interference.

Contribution

It introduces a novel code optimization algorithm for LDPC codes tailored to Gaussian interference channels, considering both strong and weak interference scenarios.

Findings

Optimized codes operate close to capacity in strong interference.

New codes enable nontrivial rate pairs in weak interference.

Finite length simulations confirm practical performance.

Abstract

In this paper, we focus on the two-user Gaussian interference channel (GIC), and study the Han-Kobayashi (HK) coding/decoding strategy with the objective of designing low-density parity-check (LDPC) codes. A code optimization algorithm is proposed which adopts a random perturbation technique via tracking the average mutual information. The degree distribution optimization and convergence threshold computation are carried out for strong and weak interference channels, employing binary phase-shift keying (BPSK). Under strong interference, it is observed that optimized codes operate close to the capacity boundary. For the case of weak interference, it is shown that via the newly designed codes, a nontrivial rate pair is achievable, which is not attainable by single user codes with time-sharing. Performance of the designed LDPC codes are also studied for finite block lengths through simulations of specific codes picked from the optimized degree distributions.