RE-HARP: RF Energy Harvesting MAC Protocol to Prolong Life Time of CRSNs

Energy drainage is a critical issue in sensor networks which is aggravated further by the incorporation of Cognitive Radio (CR). Radio Frequency Energy Harvesting (RF-EH) is a prominent method for mitigating energy constraints while providing potentially perpetual lifetime. However, its inclusion in Cognitive Radio Sensor Networks (CRSNs) instigates various Medium Access Control (MAC) layer challenges. Effective communication in a way to avoid collisions in the presence of multiple Primary Users (PUs) and CR nodes willing to access electromagnetic spectrum and EH are the significant challenges. In this paper, a MAC protocol for CRSNs which overcome challenges above is proposed. In our protocol, the CR nodes use Dedicated Common Control Channel (DCCC) for control information exchange among CR nodes and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol to access channel and avoid collisions. RF-EH technique is also incorporated to prolong the network lifetime. The proposed work is a state of the art MAC protocol in which CR nodes can communicate and harvest energy as well. Performance of the proposed protocol is evaluated in terms of throughput, harvested energy and lifetime of CRSNs by considering different parameters which include PU activities, number of CR nodes, number of flows and packet size. Simulations are performed on Network Simulator (NS-2).