A New Rate Region for General Interference Channel (Improved HK Region)

TL;DR

This paper introduces an improved rate region for the general interference channel by allowing correlated auxiliary variables and using random binning, unifying and extending previous regions like HK and CMG.

Contribution

It proposes a novel rate region for interference channels that generalizes and improves upon the Han-Kobayashi and Chong-Motani-Garg regions through correlation and binning techniques.

Findings

HK and CMG regions are special cases of the new region.

The new region achieves better rate bounds for interference channels.

Correlation of auxiliary variables enhances achievable rates.

Abstract

In this paper (a) after detailed investigation of the previous equivalent rate regions for general interference channel, i.e., the Han-Kobayashi (HK) and the Chong-Motani-Garg (CMG) regions, we define modified CMG region the equivalency of which with the HK region is readily seen; (b) we make two novel changes in the HK coding. First, we allow the input auxiliary random variables to be correlated and, second, exploit the powerful technique of random binning instead of the HK -CMG superposition coding, thereby establishing a new rate region for general interference channel, as an improved version of the HK region; (c) we make a novel change in the CMG coding by allowing the message variables to be correlated and obtain an equivalent form for our new region in (b), as an improved version of the CMG region. Then, (d) in order to exactly demarcate the regions, by considering their different easily comparable versions, we compare our region to the HK and CMG regions. Specifically, using a simple dependency structure for the correlated auxiliary random variables, based on the Wyner and Gacs-Korner common information between dependent variables, we show that the HK and the CMG regions are special cases of our new region. Keywords. Interference channel, Correlated auxiliary random variables, Common information, Superposition coding, Binning scheme