Partial Secrecy Performance Analysis for Wirelessly Powered Backscatter Communications

Existing works on the physical layer security of wirelessly powered backscatter communications (WPBC) have mainly focused on secrecy outage probability and secrecy ergodic capacity. However, these performance metrics cannot reflect the security performance when Shannon’s perfect secrecy is not achievable. To address this issue, in this paper, we investigate the partial secrecy performance of WPBC based on partial secrecy theory. Specifically, we derive closed-form expressions for the generalized secrecy outage probability and average information leakage rate of WPBC by leveraging the concept of fractional equivocation, which is the core concept of partial secrecy theory and is used to quantify the level of confusion experienced by the eavesdropper. We also derive the asymptotic expressions of these metrics in the high transmit signal-to-noise ratio (SNR) regime. Finally, simulation results validate our theoretical analysis.