Feedback Interference Alignment: Exact Alignment for Three Users in Two Time Slots

TL;DR

This paper introduces a linear feedback scheme that achieves exact interference alignment in a three-user static interference channel over two time slots, outperforming traditional methods without feedback.

Contribution

It presents a novel feedback-based linear scheme enabling exact interference alignment in static channels within two time slots, unlike prior approaches requiring infinite extensions.

Findings

Exact alignment achieved over two slots with feedback

Scheme outperforms time-sharing at finite SNR

Feedback enables practical interference management

Abstract

We study the three-user interference channel where each transmitter has local feedback of the signal from its targeted receiver. We show that in the important case where the channel coefficients are static, exact alignment can be achieved over two time slots using linear schemes. This is in contrast with the interference channel where no feedback is utilized, where it seems that either an infinite number of channel extensions or infinite precision is required for exact alignment. We also demonstrate, via simulations, that our scheme significantly outperforms time-sharing even at finite SNR.