Cellular Vehicle-to-Everything (C-V2X) is rapidly shaping the future of transportation through its ability to enable direct communication between vehicles, infrastructure, pedestrians, and networks. While much attention has been given to in-vehicle chipsets and autonomous vehicle integration, Roadside Units (RSUs)-the stationary transmitters and receivers installed along roads and intersections-are equally critical in realizing the full potential of this technology.

The Role of RSUs in C-V2X Networks

RSUs are essential enablers of V2I (Vehicle-to-Infrastructure) communication. Installed at intersections, traffic lights, and highway entry/exit ramps, these devices collect, process, and broadcast data to vehicles in real time. Their primary roles include:

• Broadcasting hazard alerts (e.g., road work or signal violations).

• Optimizing traffic flow through signal phase and timing (SPaT) messages.

• Enhancing pedestrian safety by detecting and relaying presence data.

• Supporting platooning by coordinating group vehicle movements.

As cities embrace smart infrastructure, RSUs act as key interfaces between connected vehicles and centralized traffic management systems.

RSUs in the Evolving C-V2X Ecosystem

Recent developments in chipsets and communication standards have had a ripple effect on RSU capabilities:

• Autotalks' TEKTON3 and ZTE’s ZM9300 modules, though designed for in-vehicle use, indirectly influence RSU design by setting compatibility baselines.

• RSUs are increasingly being equipped with AI-enhanced modules like ZTE’s Y2002 CVIS, enabling edge-based decision-making and analytics for real-time threat detection and prioritization of emergency vehicles.

Impact of 5G-V2X on RSU Design

With the release of 3GPP Rel. 16 and 17, RSUs must now support both LTE-V2X and 5G-V2X protocols. 5G-V2X enables:

• Groupcast communication, allowing simultaneous message delivery to multiple vehicles.

• Low-latency, high-reliability links, which are crucial for safety-critical applications like collision avoidance.

Backward compatibility ensures that newer RSUs can still communicate with vehicles using older C-V2X standards, streamlining gradual infrastructure upgrades.

Regulatory Momentum and Deployment

In the United States, the FCC’s allocation of the 5.9 GHz spectrum for C-V2X has catalyzed the transition from legacy DSRC systems to RSU-enabled V2X deployments. The U.S. DOT’s National Deployment Plan outlines phased RSU rollouts along key freight and commuter corridors.

China is aggressively deploying RSUs as part of its “vehicle-road-cloud” integration strategy, using pilot zones in major cities to verify performance across real-world scenarios.

In Europe, 5GAA projects mass deployment of 5G-V2X-enabled vehicles—and by extension, RSUs—between 2026 and 2029, with interoperability being a major focus.

Benefits of RSU Deployment

• Road Safety: By relaying timely alerts from the road environment, RSUs reduce blind spots and prevent accidents.

• Autonomous Driving Support: RSUs extend the situational awareness of autonomous vehicles beyond onboard sensors.

• Traffic Efficiency: They enable adaptive signal control, dynamic rerouting, and efficient tolling.

• Smart City Integration: RSUs connect with municipal control centers and IoT systems to support emergency services, congestion mitigation, and environmental monitoring.

Conclusion

C-V2X RSUs are not just passive infrastructure-they are active intelligence nodes that complement onboard vehicle systems and help cities transition toward safer, smarter mobility. As chipset innovations, standardization efforts, and regulatory frameworks align, RSUs will become a cornerstone of global intelligent transport systems, enabling connected mobility for years to come.