Upper-Bounding the Capacity of Relay Communications - Part I

TL;DR

This paper analyzes the capacity limits of relay communication strategies, deriving upper bounds for cutset and amplify-and-forward methods in Gaussian channels, with insights into their performance across different SNR regimes.

Contribution

It provides a mathematical framework for upper bounding relay strategy capacities, comparing cutset and AF strategies, and illustrating their performance through case studies.

Findings

Cutset strategy outperforms AF at low SNR.

Upper bounds are derived for relay strategies in Gaussian channels.

Performance varies with SNR levels.

Abstract

This paper focuses on the capacity of point-to-point relay communications wherein the transmitter is assisted by an intermediate relay. We detail the mathematical model of cutset and amplify and forward (AF) relaying strategy. We present the upper bound capacity of each relaying strategy from information theory viewpoint and also in networks with Gaussian channels. We exemplify various outer region capacities of the addressed strategies with two different case studies. The results exhibit that in low signal-to-noise ratio (SNR) environments the cutset performance is better than amplify and forward strategy.