Optimal Stochastic Power Allocation and Relay Selection for Energy Harvesting Systems

Abstract

In this letter, we develop a stochastic joint relay selection and transmit power allocation scheme for a two-hop amplify-and-forward multi-relay network, where relays harvest renewable energies from the surrounding environment. We study the optimal policy for relay selection and power allocation under unknown statistics of the channel fading and energy arrival processes. In particular, we formulate a stochastic optimization problem as an infinite-horizon Markov decision process. Then we develop a low-complexity online algorithm that does not require the statistics of the channel fading and energy harvesting processes to be known. Simulation results reveal that the developed algorithm performs close to the offline scheme proposed in the literature.