Optimal Energy Harvesting Protocols for Wireless Relay Networks

In this paper, we consider a relay network over a flat-fading channel, where the relay has no fixed power supply and thus needs to replenish energy via wireless energy harvesting (EH) from the signals transmitted by the source. We propose a novel hybrid protocol, which is a combination of existing EH protocols, such as power splitting (PS) and time switching (TS). We formulate the optimization problems and derive some explicit results. In particular, we derive the optimal PS and TS ratios at the relay for all three EH protocols to achieve the maximum throughput for information transfer from the source to the destination for both decode-and-forward and amplify-and-forward relaying schemes. We show that the proposed hybrid protocol outperforms both PS and TS protocols.