Symmetric Two-User Gaussian Interference Channel with Common Messages

TL;DR

This paper analyzes the symmetric two-user Gaussian interference channel with common messages, deriving an upper bound on sum capacity and showing that in low interference regimes, common messages do not improve capacity.

Contribution

It provides a new upper bound on sum capacity and characterizes the optimal scheme in low interference conditions, highlighting when common messages are beneficial.

Findings

Upper bound on sum capacity derived

Common messages do not increase capacity in low interference regime

Optimal scheme is to send no common messages in low interference

Abstract

We consider symmetric two-user Gaussian interference channel with common messages. We derive an upper bound on the sum capacity, and show that the upper bound is tight in the low interference regime, where the optimal transmission scheme is to send no common messages and each receiver treats interference as noise. Our result shows that although the availability of common messages provides a cooperation opportunity for transmitters, in the low interference regime the presence of common messages does not help increase the sum capacity.