Date Added: Aug 2011
Cognitive Radio (CR) is an enabling technology that allows opportunistic transmission in under-utilized or vacant frequencies, thereby resulting in high spectrum efficiency. In CR ad hoc networks, owing to the distributed operation of the nodes, ensuring that the licensed users or Primary Users (PUs) of the spectrum are not affected is a challenging task. CR nodes are neither aware of the global network topology, including the locations of the PUs, and nor do they have a priori access to PU transmission schedules. Thus, the CR nodes must rely on learning the local channel utilization through individual measurements, and share these results with neighboring nodes.