Cooperative fair multichannel MAC protocol for cognitive radio ad hoc network

A secondary user (SU) in a multichannel cognitive radio ad hoc network (CRAHN) must be able to perform a primary user (PU) sensing and communicate with other SUs. With limited transmission range, each SU may face a hidden PU sensing problem. Hence the cooperative issue is considered to avoid the problem. In addition, CRAHNs can be deployed ubiquitously, and the SUs of any CRAHN could co-exist with each other when using the frequency spectrum. It may raise a fairness issue of resource sharing between SUs. Therefore, we propose the cooperative fair multichannel medium access control (CFMC-MAC) protocol, which aims to address a hidden PU problem and to achieve a high fairness among co-existing SUs from multiple CRAHNs. In CFMC-MAC, the SU keeps its current backoff (CB) value counter when a PU claims the channel. The proposed protocol performance is simulated using network simulator (NS)-2 in terms of fairness and packet delivery ratio (PDR). The protocol is compared to the renewal backoff (RB) counter approach and modified existing 802.11 protocols. The simulation results demonstrate the proposed protocol has the higher fairness than others. Moreover, the cooperative scheme shows enhancement of fairness and PDR compared to the non-cooperative scheme.