Interference Mitigation Through Limited Receiver Cooperation: Symmetric Case

TL;DR

This paper investigates how limited receiver cooperation can mitigate interference in wireless networks, revealing the relationship between cooperation bits and interference reduction at high SNR levels.

Contribution

It provides a fundamental characterization of the capacity gain from one-bit receiver cooperation in a symmetric Gaussian interference channel, with universal strategies achieving near-optimal performance.

Findings

One-bit cooperation yields roughly one-bit gain per user when INR is below 50% of SNR.

Half-bit gain per user is achieved when INR is between 67% and 200% of SNR.

Proposed strategies achieve symmetric capacity within 3 bits universally.

Abstract

Interference is a major issue that limits the performance in wireless networks, and cooperation among receivers can help mitigate interference by forming distributed MIMO systems. The rate at which receivers cooperate, however, is limited in most scenarios. How much interference can one bit of receiver cooperation mitigate? In this paper, we study the two-user Gaussian interference channel with conferencing decoders to answer this question in a simple setting. We characterize the fundamental gain from cooperation: at high SNR, when INR is below 50% of SNR in dB scale, one-bit cooperation per direction buys roughly one-bit gain per user until full receiver cooperation performance is reached, while when INR is between 67% and 200% of SNR in dB scale, one-bit cooperation per direction buys roughly half-bit gain per user. The conclusion is drawn based on the approximate characterization of the symmetric capacity in the symmetric set-up. We propose strategies achieving the symmetric capacity universally to within 3 bits. The strategy consists of two parts: (1) the transmission scheme, where superposition encoding with a simple power split is employed, and (2) the cooperative protocol, where quantize-binning is used for relaying.