Sub-optimality of the Han--Kobayashi Achievable Region for Interference Channels

TL;DR

This paper demonstrates that the Han-Kobayashi achievable region is strictly sub-optimal for some interference channels, indicating that the true capacity region can be larger than previously thought.

Contribution

It proves that the Han-Kobayashi region is not always optimal, revealing the potential for larger capacity regions in certain interference channels.

Findings

Han-Kobayashi region is sub-optimal for some channels

Capacity region can be strictly larger than Han-Kobayashi region

Highlights limitations of existing inner bounds for interference channels

Abstract

Han-Kobayashi achievable region is the best known inner bound for a general discrete memoryless interference channel. We show that the capacity region can be strictly larger than the Han-Kobayashi region for some channel realizations, and hence the strict sub-optimality of Han-Kobayashi achievable region.