Simultaneous wireless information and power transfer for relay assisted energy harvesting network

The simultaneous wireless information and power transfer in an energy harvesting system is investigated, where a relay is self-sustained by harvesting radio-frequency (RF) energy from the transmitter and multiple user devices are distributed according to a homogeneous Poisson point process. A joint time switching and power splitting protocol for relay-assisted transmission is proposed, in which each time slot is split into two stages. In the first stage, the relay utilizes a portion of received RF signal power for energy harvesting and the remaining power for information processing. In the second stage, information is delivered from the relay to its closest destination node with the harvested energy. The outage probability, network throughput and energy efficiency are derived and analyzed in closed form. On this basis, the optimal power splitting and time switching ratio which maximizes network throughput is obtained. Simulation results are also provided to validate our theoretical analysis.