Multicoding Schemes for Interference Channels

TL;DR

This paper introduces a multicoding scheme for the 2-user interference channel that achieves the Han-Kobayashi rate region and extends to more complex scenarios like state information and overhearing, providing explicit capacity regions.

Contribution

We develop a multicoding scheme that generalizes existing interference channel coding strategies to include state information and overhearing scenarios, with explicit capacity characterizations.

Findings

Achieves the Han-Kobayashi rate region using multicoding

Extends to state-dependent deterministic Z-interference channels with capacity characterization

Provides explicit capacity regions for on/off interference and partial cribbing cases

Abstract

The best known inner bound for the 2-user discrete memoryless interference channel is the Han-Kobayashi rate region. The coding schemes that achieve this region are based on rate-splitting and superposition coding. In this paper, we develop a multicoding scheme to achieve the same rate region. A key advantage of the multicoding nature of the proposed coding scheme is that it can be naturally extended to more general settings, such as when encoders have state information or can overhear each other. In particular, we extend our coding scheme to characterize the capacity region of the state-dependent deterministic Z-interference channel when noncausal state information is available at the interfering transmitter. We specialize our results to the case of the linear deterministic model with on/off interference which models a wireless system where a cognitive transmitter is noncausally aware of the times it interferes with a primary transmission. For this special case, we provide an explicit expression for the capacity region and discuss some interesting properties of the optimal strategy. We also extend our multicoding scheme to find the capacity region of the deterministic Z-interference channel when the signal of the interfering transmitter can be overheard at the other transmitter (a.k.a. unidirectional partial cribbing).