Energy-efficient cooperative spectrum sensing in sensor-aided cognitive radio networks

Cognitive radio has been proposed to make full use of the limited spectrum resources, where spectrum sensing plays an important role to detect the channel state for opportunistic utilization. To address the hidden terminal problem, cooperative spectrum sensing is employed to improve the detection performance. Due to the energy constraint of battery-powered sensor nodes, energy efficiency emerges as a critical issue in sensor-aided cognitive radio networks. By exploiting the abundant sensor nodes and multiuser diversity, a cooperative schedule of each sensor node´s on/off can effectively extend the network lifetime. However, frequent on/off switching of sensor nodes will generate an adverse impact and make the network vulnerable and unreliable. We consider the problem of optimizing the schedule order to reduce the switch frequency. Greedy Heuristic is proposed to approach the minimum node switch with low computational complexity. Simulation results are presented to verify the performance of the proposed algorithm.