Cooperative Learning and Coordination for Cognitive Radio Networks
The raison detre for cognitive radio is that the radio spectrum is a scarce resource. Cognitive radio stretches this resource by enabling secondary users to operate in portions of the spectrum that are reserved for primary users but not currently used by the primary users. As it is whenever users share resources, coordination is a central issue in cognitive radio networks: absent coordination, there may be collision, congestion or interference, with concomitant loss of performance. Cognitive radio networks require coordination of secondary users with primary users (so that secondary users should not interfere with primary users) and of secondary users with each other. These coordination problems are especially severe because secondary users may frequently enter and exit channels within the network or the network itself.