Investigating the physical layer security of wireless sensor networks in the presence of co-channel interference signals.

Abstract

Security performance of resource constrained sensor networks in the presence of multiple eavesdroppers is investigated. The impact of co-channel interference signals on the secrecy performance of a multiuser scheme that adopts transmit antenna selection (TAS) at the base station and selection combining (SC) over the legitimate nodes is investigated. The transmitted signal su ers from multiple eavesdroppers that try to overhear the transmitted information. We study the system performance for two eavesdropper scenarios: unavailable channel state information (CSI) of the eavesdropper and availability of eavesdropper CSI. The interference signals are assumed to harm both the eavesdroppers and the legitimate users. The network su ers from the presence of multiple collaborating and non-collaborating eavesdroppers that try to overhear the transmitted information. Speci cally, we present closed-form expressions for the legitimate node instantaneous signal-to-interference plus noise ratio. Moreover, for the case with no eavesdropper CSI, we derive closed form expressions for the secrecy outage probability (SOP). In order to draw more insights into the system secrecy performance in the high SINR regime, we derived closed form expressions for the asymptotic secrecy outage probability (ASOP). In addition, for the case of available eavesdropper CSI we derive closed-form expression for the ergodic secrecy rate and the secrecy throughput. Where the eavesdroppers are collaborating, it is seen from the SOP and ASOP expressions and simulations that the system performance is lower than when the eavesdroppers are non-collaborating. The secrecy performance of the system model is then compared with other existing state of the art schemes such as transmit antenna selection/switch and stay combining (TAS/SSC). Finally, we present exact numerical and asymptotic results to justify our analysis.