MC-MAC: An Efficient Multichannel MAC Protocol for Cognitive Radio Ad Hoc Networks

A cognitive radio ad hoc network (CRAHN) is a group of autonomous users that work in ad hoc mode. This network enables a secondary user (SU) to use the frequency spectrum opportunistically when the primary user (PU) does not utilize it. CRAHNs can be deployed ubiquitously, and SUs of any CRAHN could co-exist when utilizing the spectrum. This situation leads to the fairness issue of spectrum resource sharing between SUs. CRAHN deployment is a large challenge in the medium access control (MAC) protocol design in which it must actively encourage each SU to operate for a high fairness. Most of the developed multichannel MAC protocols for CRAHN have not deliberated a fair resource sharing mechanism between co-existing SUs. Therefore, we propose an efficient multichannel (FMC) MAC protocol to address the dynamic availability of the spectrum and which orientates to the fairness in resource sharing. In this proposed protocol, the SU keeps the current backoff (KCB) counter when a PU appears to claim the intended channel. We compare the proposed fair protocol to the renewal backoff (RB) counter approach and the modified existing 802.11 protocol. The performance evaluation exhibits our protocol by providing a higher fairness than others while maintaining a high throughput.