Optimal configuration for STAR-RIS-assisted low-latency V2I communication systems

Reconfigurable Intelligent Surface (RIS) has emerged as an advanced metasurface technique to enhance wireless communication performance in various mobile networks, including Vehicle-to-Everything (V2X) networks. By adaptively reshaping wireless channels, RIS can enhance the incoming signal and redirect it to the desired destination effectively. As a major branch of V2X, the demand for Vehicle-to-Infrastructure (V2I) communications to efficiently transmit data among vehicles and omnipresent Roadside Units (RSUs) has increased significantly in recent years. The Simultaneously Transmitting and Reflecting RIS (STAR-RIS), which allows both penetration and reflection of wireless signals, has been proposed as a competitive choice for V2X. However, the configuration of STAR-RIS for latency control of V2I communications has not been well investigated. In this paper, we investigate the latency minimization problem in STAR-RIS-assisted V2I communication systems under practical constraints. We design an efficient Differential Evolution (DE) based optimizer to obtain the STAR-RIS configurations to minimize the maximum system latency, and evaluate its performance through simulations. A comparative study is presented with respect to pure V2I communication systems to demonstrate the significance of STAR-RIS in V2I communication systems.