Secrecy Outage for Wireless Sensor Networks

This letter addresses physical layer security (PLS) for a wireless sensor network, in which multiple sensor nodes communicate with a single sink in the presence of an eavesdropper. Under the assumption of sink using outdated channel state information (CSI) of the eavesdropper link, the outage probability of achievable secrecy rate under Weibull fading is investigated and its analytical expressions are derived. Specifically, we consider sensor scheduling to enhance PLS, thereby, we quantify the degradation in outage probability due to outdated CSI under the best-node scheduling scheme and compare it with conventional round-robin scheduling. Finally, we analyze secrecy outage probability conditional on successful transmission and provide practical insights into the effect of outdated CSI of the eavesdropper. The derived theoretical results are validated through simulations.