Joint Beamforming and IRS Phase Design for Secure V2I Communications in Intelligent Transportation Systems
IEEE Transactions on Consumer Electronics, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Publication Date: 2026
- Doi Number: 10.1109/tce.2026.3702689
- Journal Name: IEEE Transactions on Consumer Electronics
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Compendex, INSPEC, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Keywords: Intelligent reconfigurable surfaces, Intelligent transportation systems, secrecy rate optimization
- Istanbul Gelisim University Affiliated: Yes
Abstract
This paper studies an intelligent reflecting surface (IRS)-assisted secure downlink vehicle-to-infrastructure (V2I) communication system, where a multi-antenna roadside unit (RSU) serves legitimate vehicles while multiple passive eavesdropping vehicles are present. By exploiting both the direct and IRS-reflected links, we formulate a secrecy sum-rate maximization problem through the joint design of the RSU beamforming vectors and the IRS phase shifts, subject to the RSU transmit power constraint and the unit-modulus IRS hardware limitations. To tackle the resulting non-convex problem, we develop an efficient alternating-optimization framework that iteratively updates the RSU beamforming and IRS configuration via tractable convex surrogates and unit-modulus projection. Numerical results verify the fast convergence of the proposed algorithm and demonstrate significant secrecy performance improvements over benchmark schemes, including random IRS and no-IRS transmission. The results further show that the secrecy gains increase with the number of IRS elements, while they decrease as the number of eavesdroppers grows due to the worst-case interception effect.