Combined pre-detection and sleeping for energy-efficient spectrum sensing in cognitive radio networks

In this paper, we propose a cooperative spectrum sensing scheme including a combined pre-detection and sleeping policy. In the scheme, the designed pre-detection sub-phase is applied at the beginning of the detection of the presence of a primary user, where all sensing nodes are involved to improve the detection performance. The sleeping policy is applied for each sensing node respectively at the end of the pre-detection sub-phase and the beginning of the transmission of the local detection results, in order to decrease sensing energy consumption. We formulate the problem of minimizing the maximum average energy consumption per sensing node in Rayleigh fading channels, considering the constraints of the required global detection and false alarm probabilities and the tolerable interference caused to the primary user. Numerical results show that the scheme achieves significant energy saving as compared to a scheme that includes only a sleeping policy and does not consider pre-detection.