Optimized Broad-Range Null-Steering Incorporated with O-RAN-Based Beam Tracking for Millimeter-Wave V2X

The coordination of connected autonomous vehicles (CAVs) is expected to facilitate more efficient route planning and improve safety by enabling the exchange of sensor data between roadside infrastructure and other vehicles. Given the substantial volume of sensor data involved, the utilization of the millimeter-wave (mmWave) band is essential. While mmWave supports high-speed and high-capacity data transmission, wireless communication systems for CAVs are subject to radio signal degradation caused by vehicle mobility. To address these challenges, previous studies have proposed broad-range null-steering (BRNS) integrated with beam tracking to stabilize multi-user spatial multi-plexing transmission in high-speed mobile environments. BRNS utilizes signal radiation angles derived from location information to steer additional nulls toward interfering vehicles, thereby enhancing inter-user interference (IUI) suppression. Meanwhile, our previous approach, additional null-steering, relied on fixed mannar which limits its adaptability and efficiency. To resolve this issue, this paper newly proposes optimization of angular-based null space expansion exploiting vehice traveling onformation provided through O-RAN and cooperative awareness message. Its effectiveness is validated through sophisticated computer simulations combining realistics traffic simulator.