Optimisation study of power allocation and relay location for amplify‐and‐forward systems over Nakagami‐ m fading channels

Abstract

ABSTRACTWe consider power allocation (PA) and relay positioning in a dual‐hop amplify‐and‐forward relaying system over Nakagami‐m fading channels. We investigate adaptive PA with fixed relay location, optimal relay location with fixed PA, and joint optimisation of the PA and relay location under transmit power constraint in order to minimise average error probability and outage probability. Analytical results are validated by numerical simulations and comparisons between the different optimisation schemes and their performance are provided. Results show that optimum PA brings only coding gain, whereas optimum relay location yields, in addition to the latter, diversity gains as well. Also, joint optimisation improves both, the diversity gain and coding gain. Furthermore, results illustrate that the analysed adaptive algorithms outperform uniform schemes. Copyright © 2012 John Wiley & Sons, Ltd.