Statistical Channel Modeling and Performance Analysis of Physical Layer Security in RIS-Assisted Wireless Communication Systems

Reconfigurable intelligent surface (RIS) has recently emerged as a key enabling technology for enhancing physical layer security by reconfiguring wireless propagation environments. However, most existing studies rely on oversimplified channel models, thereby limiting their applicability in realistic scenarios. To overcome these limitations, this paper develops a comprehensive three-dimensional statistical channel model for RIS-assisted single-input single-output communication systems, incorporating both RIS-reflected and direct propagation links under near field and rich-scattering propagation conditions, with respect to physical structure of the RIS and multipath fading modeling. Based on this model, the secrecy performance in terms of secrecy capacity and secrecy outage probability is evaluated with mainstream RIS configuration strategies. The impacts of various factors, including RIS deployment geometry, the physical structure and the RF characteristics of the RIS, and user locations, as well as practical non-ideal factors such as channel estimation errors and finite RIS control bits, are thoroughly investigated. Simulation results reveal that the secrecy performance critically depends on the size and the deployment position of the RIS. These findings provide valuable design guidelines for implementing RIS-assisted secure wireless communication in realistic scenarios.