Relay and Power Splitting Ratio Selection for Cooperative Networks with Energy Harvesting

This paper addresses the problem of joint relay and power splitting ratio selection along with power allocation for an energy harvesting (EH) cooperative network, where the source and the relays can harvest energy from natural sources (e.g., solar) and radio frequency (RF) signals, respectively. To effectively use the harvested energy from the source, the relays employ the power splitting technique to scavenge energy from RF signals radiated by the source. We formulate this problem into a non-convex constrained optimization problem with the objective of maximizing system payoff, which is defined as the difference between system transmission benefit and system energy cost, and meanwhile minimizing system outage probability in both offline and online settings. In particular, we consider both direct transmission and relay transmission in this paper. Relay transmission is selected dynamically based on network channel conditions and available energy of EH nodes. Our simulation results reveal that considering direct transmission and selecting relay transmission and power splitting ratio dynamically can greatly improve system performance.