Optimal Sensing Scheduling for Green Cognitive Radio

Cooperative sensing provides an effective method for exploiting spectrum opportunities as a mechanism for implementing Cognitive Radio Network. Secondary Users (SU) are coordinated to perform spectrum sensing in order to detect the activities of Primary User (PU) more efficiently. Cooperation among secondary users increases reliability of spectrum detection at the expense of cost and energy for sensing. In order to minimise the energy consumption and to optimise the opportunity cost, a modified cooperative sensing scheduling framework is proposed where all primary channels are sensed cooperatively within a cycle consisting of different rounds. In each round, PU channels are sensed by corresponding Secondary Users(SU) which are assigned to sense them. SUs reports this sensing result to a Fusion Center (FC) for global decision. Finally, channel switching is performed for the next round by those SUs which are allotted to sense other PUs. By doing so, a network set up is obtained which not only offers sufficient number of SUs for PU protection in each round, but also an energy efficient sensing method and thus providing apparent opportunity cost reduction.