Noisy Channel-Output Feedback Capacity of the Linear Deterministic Interference Channel

TL;DR

This paper fully characterizes the capacity region of a two-user linear deterministic interference channel with noisy output feedback, revealing when feedback benefits one or both users and when it is ineffective.

Contribution

It provides a complete capacity characterization for the LD interference channel with noisy feedback, identifying scenarios where feedback is beneficial or redundant.

Findings

Feedback in one link can match the benefit of both links in some cases.

In some scenarios, feedback does not improve capacity even with noiseless links.

The capacity region depends on the asymmetry of feedback benefits.

Abstract

In this paper, the capacity region of the two-user linear deterministic (LD) interference channel with noisy output feedback (IC-NOF) is fully characterized. This result allows the identification of several asymmetric scenarios in which imple- menting channel-output feedback in only one of the transmitter- receiver pairs is as beneficial as implementing it in both links, in terms of achievable individual rate and sum-rate improvements w.r.t. the case without feedback. In other scenarios, the use of channel-output feedback in any of the transmitter-receiver pairs benefits only one of the two pairs in terms of achievable individual rate improvements or simply, it turns out to be useless, i.e., the capacity regions with and without feedback turn out to be identical even in the full absence of noise in the feedback links.