Secrecy Performance of Cognitive Radio Sensor Networks with an Energy-Harvesting based Eavesdropper and Imperfect CSI

Abstract

From the point of physical layer security, we investigate the secrecy performance of cognitive radio sensor networks (CRSN) with an energy harvesting (EH) based eavesdropper. The closed-form expressions of secrecy outage probability (SOP) are derived when considering the imperfect channel state information (CSI) of secondary user links and the constraint cases of the transmit power of secondary users. One constraint case is that the transmit power is limited by the interference threshold of primary user receiver to protect the primary communication; the other is that the transmit power equals the minimum one in the interference power threshold of primary user receiver and the maximal transmit power of secondary users by considering the practical condition of secondary user transmitters. Meanwhile, the power splitting factor of EH at the eavesdropper is derived to obtain the maximal eavesdropping capacity. The effect of the channel state, the interference threshold of primary user receiver, and the splitting factor of EH is analyzed on the SOP.