Feedback through Overhearing

TL;DR

This paper investigates the capacity benefits of overhearing feedback in a two-hop interference channel, showing when it can match dedicated feedback and improve overall communication efficiency.

Contribution

It introduces a model for overhearing feedback in interference channels and derives capacity bounds, revealing when overhearing enhances performance.

Findings

Overhearing can provide non-negative capacity gains.

In certain parameters, overhearing matches dedicated feedback performance.

Insights into effective overhearing transmission strategies.

Abstract

In this paper we examine the value of feedback that comes from overhearing, without dedicated feedback resources. We focus on a simple model for this purpose: a deterministic two-hop interference channel, where feedback comes from overhearing the forward-links. A new aspect brought by this setup is the dual-role of the relay signal. While the relay signal needs to convey the source message to its corresponding destination, it can also provide a feedback signal which can potentially increase the capacity of the first hop. We derive inner and outer bounds on the sum capacity which match for a large range of the parameter values. Our results identify the parameter ranges where overhearing can provide non-negative capacity gain and can even achieve the performance with dedicated-feedback resources. The results also provide insights into which transmissions are most useful to overhear.