Ergodic Secracy Capacity Analysis of Intelligent Reflecting Surface-Aided Vehicular Communication Systems with Dynamic Eavesdropping

The integration of intelligent reflecting surfaces (IRS) in vehicular communication systems offers unprecedented opportunities for enhancing physical layer security. This paper investigates the ergodic secrecy capacity (ESC) of IRS-aided vehicular networks under dynamic eavesdropping scenarios. Novel closed-form expressions are derived for ESC considering realistic Rician fading channels, vehicle mobility, and time-varying eavesdropper positions. The analytical framework accounts for Doppler effects, path loss, and optimal IRS phase shift design. Monte Carlo simulations shows excellent agreement with theoretical results ( deviation \(( < )\) 3\((%)\)). Performance evaluation reveals that 64-element IRS configurations can maintain secure communications at vehicle speeds up to 120 km/h while achieving 4.00 bits/s/Hz ergodic secrecy capacity and mobility degradation factor increases from 0.52 at 30 km/h to 0.69 at 120 km/h. The proposed system finds practical applications in autonomous vehicle platoons, Vehicle-to-Everything (V2X) payment systems, and military convoy communications.