Optimal power allocation and relay placement for wireless information and RF power transfer

Abstract

In this paper, we develop an optimization framework to jointly optimize the efficiency of wireless information and RF power transfer to the destination of a two hop decode- and-forward source-relay-destination network. In particular, we investigate the performance of three optimization schemes: (i) optimal power allocation (PA) with fixed relay placement (RP), (ii) optimal RP with fixed PA, and (iii) joint optimization of PA and RP, for minimizing the outage probability under the harvested power constraint at the destination. In absence of direct source to destination reachability, closed-form global-optimal solutions are obtained for all three optimization schemes. Numerical results show that the optimized schemes significantly outperform fixed allocation and the joint optimal PA and RP provides an outage improvement of about 35%. Also, a tradeoff exists between minimized outage probability and minimum required average harvested power at destination for its uninterrupted operation.