Achievable Rates and Optimal Resource Allocation for Imperfectly-Known Fading Relay Channels

TL;DR

This paper investigates achievable data rates and optimal resource allocation in relay channels with imperfect channel knowledge, considering various relaying schemes and resource constraints to enhance energy efficiency.

Contribution

It introduces new achievable rate expressions and optimal resource allocation strategies for imperfectly-known fading relay channels with different relaying schemes.

Findings

Optimal power and time/bandwidth allocation strategies identified.

Achievable rates derived for amplify-and-forward and decode-and-forward schemes.

Energy efficiency analyzed in low-SNR conditions.

Abstract

In this paper, achievable rates and optimal resource allocation strategies for imperfectly-known fading relay channels are studied. 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 with different degrees of cooperation are considered, and the corresponding achievable rate expressions are obtained. Three resource allocation problems are addressed: 1) power allocation between data and training symbols; 2) time/bandwidth allocation to the relay; 3) power allocation between the source and relay in the presence of total power constraints. The achievable rate expressions are employed to identify the optimal resource allocation strategies. Finally, energy efficiency is investigated by studying the bit energy requirements in the low-SNR regime.