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

TL;DR

This paper derives approximate capacity regions for the two-user Gaussian interference channel with noisy feedback, using coding strategies and outer-bounds, showing they are within a constant gap of the true capacity.

Contribution

It introduces new outer-bounds and combines existing techniques to approximate the capacity region of the G-IC-NOF within a constant gap.

Findings

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

New outer-bounds are derived using genie-aided models.

The combination of techniques effectively characterizes the capacity region.

Abstract

In this research report, 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.