Secrecy Performance of SWIPT Cognitive Radio Networks with Eavesdropper's Decoding Capability

The concept of secrecy outage probability is a fundamental aspect used to study the performance of secrecy in wireless communication networks. While this metric constitutes the key element of secrecy performance evaluation, a more advanced approach involves scrutinizing the eavesdropper's capacity to decode the information. The issue of secrecy becomes critical in our proposed system model for cognitive radio network (CRN) featuring simultaneous wireless information and power transfer (SWIPT). In this context, security concerns arise related to spectrum sharing in CRNs, with the energy harvester in SWIPT potentially acting as an eavesdropper. We conduct an in-depth analysis using the concept of fractional equivocation to assess the severity of eavesdropper's decodability of the information. The chosen secrecy metric offers a more comprehensive understanding of secrecy in SWIPT-CRN, facilitating the design of secure communication systems with diverse perspectives on secrecy measurement. We derive a closed-form analytical expression for the exact generalized secrecy outage probability (GSOP) of the network. This expression conveys the GSOP's dependence on system parameters associated with the eavesdropper's decoding capability, which we illustrate through numerical analysis. Asymptotic analysis is performed to gain better insights into the system.