Discussion on Applying Wireless Information and Power Transfer to Relay Networks

Recently, there have been numerous research works on applying wireless information and power transfer (WIPT) to relay networks. In this letter, we first include the path-loss effect in the performance evaluation of WIPT-based relay networks. Results reveal that the received signal quality of these networks is generally much worse than that of direct transmission due to the enlarged path loss, and then a large amount of energy must be harvested at the relay node before the actual information-forwarding process. Based on this observation, we also show that suitably employing multiple energy-harvested relays can help in overcoming the unfavorably large path loss induced, and therefore let WIPT-based relaying become rational for practical implementation.