Intercept Probability Analysis of Wireless Networks in the Presence of Eavesdropping Attack With Co-Channel Interference

In this paper, the joint effect of fading and co-channel interference on the secrecy performance of a wireless communications system is studied. Considering a practical setting where a transmitter (Alice) communicates with a multi-antenna legitimate receiver (Bob) in the presence of a multi-antenna eavesdropper (Eve), we study the secrecy performance of the proposed system when maximal ratio combining is employed. The probability density function and cumulative distribution function of the output signal-plus-interference-to-noise ratio are derived. Given these formulations, we derive a novel analytical expression for the exact intercept probability, which takes into account the number of interfering signals and the fading characteristics of the wireless environment. In addition, we provide a comprehensive diversity analysis, where we derive simple asymptotic intercept probability expressions and explicitly show the impact of system parameters on the diversity order and secrecy coding gain. Throughout the asymptotic analysis, we consider various scenarios based on the interfernece-to-noise ratios at the legitimate receiver and the eavesdropper, as well as the average signal-to-noise ratio of the eavesdropper and examine their impact on the physical layer security of the wireless system. Finally, Monte-Carlo simulations are conducted to assess our proposed analysis.