A New Relay Policy in RF Energy Harvesting for IoT Networks-A Cooperative Network Approach

In this paper, a new RF energy harvesting (RF-EH) policy is proposed for Internet of Things (IoT) networks using cooperative communication approach. The proposed policy is evaluated in three devices network which are source, relay, and destination. Such a network model can be adopted in most IoT networks. Three scenarios are studied, where the relay has RFEH capability with limited battery in all scenarios. However, the source has unlimited energy in the first scenario, but the limited energy in the second and third ones. In addition, in the third scenario source has RF-EH capability. New analyses based on discrete phase-type distribution (D-PHD) model as well as a simple analytical method (SAM) are presented to derive performance metrics which are network effective lifetime, average delay of source/relay packets, and source packets overflow. The effect of energy harvesting on such metrics are investigated to find the optimum relay policy. Results show that the proposed policy can maximize network effective lifetime in comparison with time switching (TS) and power splitting (PS)-based protocols.