Relay Selection Scheme for Energy Harvesting IoT Networks with Direct Link

In this paper, we propose a relay selection scheme in an energy-harvesting relay Internet of things network, which contains a source node, a multi-relay node and a destination node. The direct link between the source node and the destination node is used for signal transmission. In the proposed scheme, the relay selection is based on the instantaneous channel status information of the wireless link, which can decrease the outage probability. In addition, the relay node employs the technique of simultaneous wireless information and power transfer to harvest energy, and each relay node is equipped with a power splitter to split the received signal into signal processing part and energy harvesting part. A closed-form and simple asymptotic expression for the outage probability of the proposed relay selection scheme is provided. Computer simulations confirm that the optimal power splitting factor of each relay node is able to minimize the outage probability. We have also verified the effectiveness of the devised strategy.