Approximate Capacity of the Gaussian Interference Channel with Noisy Channel-Output Feedback

TL;DR

This paper characterizes the approximate capacity region of the two-user Gaussian interference channel with noisy feedback, using novel bounds and coding techniques to achieve a constant-gap approximation.

Contribution

It introduces new outer bounds and combines established coding strategies to approximate the capacity of the G-IC-NOF within a constant gap.

Findings

Achievability and converse regions are within a constant gap of the true capacity.

New genie-aided outer bounds improve the understanding of the channel capacity.

The approach provides a near-complete characterization of the G-IC-NOF capacity.

Abstract

In this paper, an achievability region and a converse region for the two-user Gaussian interference channel with noisy channel-output feedback (G-IC-NOF) are presented. The achievability region is obtained using a random coding argument and three well-known techniques: rate splitting, superposition coding and backward decoding. The converse region is obtained using some of the existing perfect-output feedback outer-bounds as well as a set of new outer-bounds that are obtained by using genie-aided models of the original G-IC-NOF. Finally, it is shown that the achievability region and the converse region approximate the capacity region of the G-IC-NOF to within a constant gap in bits per channel use.