On the Capacity of the 2-user Gaussian MAC Interfering with a P2P Link

TL;DR

This paper analyzes the capacity limits of a communication setup where a 2-user Gaussian MAC interferes with a P2P link, providing bounds and conditions for optimal performance.

Contribution

It derives an outer bound for the capacity region and identifies cases where this bound is achievable, especially under strong interference conditions.

Findings

Outer bound for capacity region derived

Achievability shown in strong interference cases

Sum capacity bound nearly tight at low interference

Abstract

A multiple access channel and a point-to-point channel sharing the same medium for communications are considered. We obtain an outer bound for the capacity region of this setup, and we show that this outer bound is achievable in some cases. These cases are mainly when interference is strong or very strong. A sum capacity upper bound is also obtained, which is nearly tight if the interference power at the receivers is low. In this case, using Gaussian codes and treating interference as noise achieves a sum rate close to the upper bound.