Energy Efficiency Analysis of Bidirectional Wireless Information and Power Transfer for Cooperative Sensor Networks

In this paper, we study the energy efficiency of bidirectional wireless information and power transfer in cooperative sensor networks, where the relay node can decode and forward information from the sensor node (SN) to base station (BS), and assist the wireless power transfer from the BS to SN. For the power splitting protocol, we propose the joint power allocation scheme to maximize the energy efficiency. For the time switching protocol, the optimal power allocation strategy and the optimal time allocation scheme are derived by studying the derivative of the energy efficiency. Simulation results are provided to verify the performance of our proposed schemes for the cooperative sensor networks.