To Cooperate, or Not to Cooperate in Imperfectly-Known Fading Channels

TL;DR

This paper analyzes the performance of relay communication strategies over imperfectly-known fading channels, focusing on optimal resource allocation and energy efficiency in various cooperation protocols.

Contribution

It introduces achievable rate expressions for different cooperation protocols and determines optimal resource and power allocation strategies under practical constraints.

Findings

Optimal relay time and bandwidth allocation identified.

Power allocation strategies improve energy efficiency.

Achievable rates depend on channel estimation accuracy.

Abstract

In this paper, communication over imperfectly-known fading channels with different degrees of cooperation is studied. The three-node relay channel is considered. It is assumed that communication starts with the network training phase in which the receivers estimate the fading coefficients of their respective channels. In the data transmission phase, amplify-and-forward and decode-and-forward relaying schemes are employed. For different cooperation protocols, achievable rate expressions are obtained. These achievable rate expressions are then used to find the optimal resource allocation strategies. In particular, the fraction of total time or bandwidth that needs to be allocated to the relay for best performance is identified. Under a total power constraint, optimal allocation of power between the source and relay is investigated. Finally, bit energy requirements in the low-power regime are studied.