Vehicle-to-Everything (V2X) Communications in Unlicensed Spectrum Can Be Safe and Efficient

To meet the communications demands of connected vehicles, the wireless devices deployed in vehicles and on roadside infrastructure may need access to more spectrum than is available today. This paper proposes a novel approach that allows connected vehicle devices using V2X technology (e.g., C-V2X or NR-V2X) to share spectrum with Wi-Fi and other unlicensed devices, thereby gaining access to more spectrum. The proposed approach requires no change to Wi-Fi technology so there is no need to replace Wi-Fi devices that have been deployed, and only modest modifications to V2X which reduces cost and complexity. It uses a backward-compatible form of beaconing. Unlike previous work, the resources allocated to V2X are dynamically adjusted for greater efficiency. The approach also does not require involvement from a cellular operator or other centralized controller. One spectrum band where this approach could be especially beneficial is adjacent to the Intelligent Transportation System (ITS) band, where this approach could help meet the needs of both connected vehicles and Wi-Fi 6. Simulation results show that it is possible to protect quality of service for both V2X and Wi-Fi communications in a shared band, while greatly improving spectrum efficiency. This paper also describes steps that standards bodies (IEEE 802.11 and 3GPP) and spectrum regulators could take to advance this spectrum-sharing approach.