Date Added: Feb 2012
In cognitive radio ad hoc networks, the MAC layer plays an important role of arbitrating and scheduling unlicensed users' access to the licensed spectrum bands. Recently, a number of MAC protocols have been proposed in the paper, but most of them are restricted with numerous limitations and assumptions with respect to practical applications. In this paper, the MAC protocols proposed so far are examined rigorously. The authors are systematically categorized on the basis of Common Control Channel (CCC) requirement and, then, their design and implementation are reviewed and compared in terms of main features and performance.