Securing Cellular-V2X at Physical Layer: A Two-Stage User Authentication for Massive MIMO Systems

Wireless technologies in intelligent transportation systems are evolving rapidly globally. Dedicated short-range communications standards are insufficient to meet the growing demand for data exchange on roads. Cellular Vehicle-to-Everything (C-V2X) using massive multiple-input and multiple-output (MIMO) technology provides high data rates, massive connectivity, and low latency. However, the broadcasting nature of wireless media poses security risks. This paper addresses the challenge of securing wireless transmission in massive MIMO systems at the physical layer. It calculates the average outage probability based on long-term evaluation (LTE)-V2X link behavior and proposes a two-stage user authentication mechanism to identify suspicious users requesting extra bandwidth. Eavesdroppers are detected using pilot signals, and their information is captured and limited through beacon information. The findings suggest that mobility affects bandwidth requests, making mobile users less likely to be eavesdroppers compared to stationary users.