Secrecy Outage Performance of SWIPT Cognitive Radio Network With Imperfect CSI

We consider a cognitive radio (CR) network with simultaneous wireless information and power transfer (SWIPT) system having one base station (BS) with multiple antennas that acts as a secondary transmitter, one desired information receiver (IR) acting as secondary receiver, multiple primary users (PUs) having licenses band of spectrum, and multiple energy harvesting receivers (EHRs). The EHRs harvests energy from the BS and eavesdrop the information from signal. In order to extract the information and then harvest energy from that signal, power splitting is considered in each EHR. On the basis of an imperfect channel state information (CSI) in IR, selection of the best transmit antenna at the BS is made. The effect of path loss on the system is also considered. The derivation of analytical expression in closed-form is provided for the exact secrecy outage probability (SOP) of the network. The derived expression highlights the variation in the secrecy outage of the considered CR SWIPT system relying on imperfect CSI with respect to the system parameters, which is depicted through numerical analysis. Furthermore, we derive the asymptotic SOP and study the effects of different system parameters on the secrecy diversity order and secrecy array gain.