A Novel Media Access Scheme in Cognitive Radio Ad Hoc Networks with Handshaking Mechanisms

In this paper, we propose a novel Media Access Control (MAC) scheme for Cognitive Radio Ad Hoc Networks (CRAHNs). The scheme includes two mechanisms. One mechanism is called Exposed Terminal Secondary users Communication (ETSC), which allows a Secondary User (SU) to continue communication attempt even when the occupied channel could be used by a new Primary User (PU). The other is called Four-Stage RTS/CTS Back protocol (FSRCB) of PUs by which the communication links between PUs can be created after at most four RTS/CTS shacking attempts. FSRCB can support a PU receiver which is in the interference area of a SU sender, and decrease transmission power to increase frequency utilization efficiency. Compared with the traditional "PU-driven SU self- termination" scheme, our scheme can achieve much better performance, including lower dropping rate, higher success rate, higher throughput, higher channel utilization efficiency, and lower blocking probability.