Limited reporting-based cooperative spectrum sensing for multiband cognitive radio networks

The performance of cooperative spectrum sensing depends on the sensing time, the reporting time of transmitting sensing results, and the fusion scheme. While longer sensing and reporting time will improve the sensing performance, this shortens the allowable data transmission time, which in turn degrades the throughput of secondary users. In a cognitive radio network with multi-primary bands, the reporting time increases with the number of reporting nodes and primary bands to be reported. This paper proposes a limited reporting scheme for multiband cooperative spectrum sensing with a soft combination rule in order to reduce the reporting time while satisfying the detection probability constraint. In the proposed reporting scheme, the upper bound of the number of reporting nodes and the reported primary bands are dynamically controlled according to the number of cooperative secondary users. We formulate a trade-off between the throughput of secondary users and the overheads of cooperative spectrum sensing. Simulation results show that the sensing time and reporting time should be jointly optimized in order to maximize the throughput of secondary users. Moreover, in comparison with the conventional sensing-throughput optimization schemes, the proposed reporting scheme significantly increases the throughput of secondary users by reducing the reporting time.