chapter  2
45 Pages

Cognitive Radio Networks

Cognitive radio (CR) is a wireless communication paradigm utilizing all available resources more efficiently with its ability to self-organize, self-plan, and self-regulate. Devices with cognitive capabilities can be networked to create cognitive radio networks (CRNs), which are recently gaining momentum as viable architectural solutions to address the limited spectrum availability and the inefficiency in spectrum usage. In cooperative CRN (CCRN), secondary users (SUs) are able to negotiate with primary users (PUs) for dedicated transmission opportunities through providing tangible service. PUs typically obtains licenses to operate wireless services, such as cellular networks, by paying spectrum regulators. In CCRN, the scenario consisting of one primary network with primary base stations (BSs) and multiple PUs, and one secondary network with a secondary BS and multiple SUs is considered. In multihop CRNs, the local view of available resources is not necessarily identical in all nodes due to the physical separation of nodes.