Physical Layer Security Performance Analysis and Evaluation of Heterogeneous Vehicular Networks Using Stochastic Geometry

The heterogeneous vehicular networks (HVNs) in-tegrate various vehicular radio access technologies (VRATs) to enhance user capacity, coverage, and quality of experience. How-ever, the rapid topology changes in HVNs make it challenging for traditional encryption methods that rely on trusted third parties (TTPs) for key management. Physical layer security (PLS) technology emerges as a powerful complementary solution by enabling key generation and distribution without TTPs. In this paper, we investigate the effects of VRAT bandwidth, beamforming parameters, and road parameters on the uplink PLS metrics of HVNs. Specifically, we build a spatial model for HVNs using stochastic geometry, which characterizes the irregularity and randomness of HVNs. Then, we derive two closed-form expressions of PLS metrics for HVNs, connection outage probability (COP) and secrecy outage probability (SOP). Monte-Carlo simulations results demonstrate that higher communication bandwidth brings lower COP but also increases SOP, and the mainlobe width significantly affects SOP but has less effect on COP. In particular, the SOP and COP of VRATs are related to the rate threshold and the system parameters should be optimally designed.