C-V2X Explained: What Is It and How Does It Work?

Cellular Vehicle-to-Everything (C-V2X) is an advanced communication technology that allows vehicles to connect with other vehicles, pedestrians, cyclists, and roadside infrastructure. This connectivity enables the exchange of critical information, enhancing road safety, reducing traffic congestion, improving journey efficiency, and lowering emissions.

The Two Key Communication Modes of C-V2X

C-V2X operates through two complementary transmission modes: direct communication (PC5) and network communication (Uu). The combination of these two communication methods makes C-V2X a versatile and powerful solution for connected mobility.

Direct and network communication connect entities on and around the road to enhance safety and efficiency.

Direct Communication (PC5): "Sidelink" Communication

Direct communication allows entities to communicate without relying on cellular network infrastructure. This method, also known as Sidelink communication, enables communication between:

• On-Board units (OBUs) installed in vehicles

  
  

• Roadside Units (RSUs) mounted on infrastructure like traffic lights and signal poles

  
  

• Vulnerable road users such as pedestrians and cyclists with their own OBUs or wearable devices enabling V2X communication

  
  

By connecting vehicles directly to each other, infrastructure, and vulnerable road users, direct communication enhances vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-pedestrian (V2P) communication.

Network Communication (Uu): Indirect Communication

Network communication, also called indirect communication, leverages existing cellular networks to provide drivers with important information about road conditions, traffic, and other factors.

This communication involves two main processes:

• Uplink communication: Transmitting data from a vehicle to a cellular network or satellite

  
  

• Downlink communication: Sending data back from the network to the vehicle

  
  

Network communication expands C-V2X’s capabilities, allowing for vehicle-to-network (V2N) transmission, which supports longer-range communication between vehicles and infrastructure.

The Benefits of Combined Direct and Network Communication

The combination of direct and network communication allows C-V2X to offer a wide range of use cases:

• Short-range communication: Using V2V, V2I, and V2P to improve safety and efficiency on the road

  
  

• Long-range communication: Using V2N to provide additional services, such as real-time traffic information and updates on road conditions

  
  

This integrated system ensures that the most appropriate and efficient communication method is used depending on the specific use case, making C-V2X adaptable to a variety of scenarios.

Standardization and Evolution of C-V2X

C-V2X was first standardized in 2017 by the 3rd Generation Partnership Project (3GPP), a global standardization body for mobile networks. This initial standardization, known as LTE-V2X, was finalized in Release 15 of the 3GPP standards.

LTE-V2X: The First Step in C-V2X Evolution

The LTE-V2X standard brought together direct and mobile communication to support both basic safety applications and advanced use cases. Key features include:

• High Definition Sensor Sharing

  
  

• Speed Harmonization

  
  

• Vehicle Platooning

  
  

• Cooperative Lane Merging

  
  

These advanced use cases are foundational for the future of automated and connected transportation.

The Future with 5G-V2X

With the evolution of 5G technology, the next-generation standard 5G-V2X is expected to provide:

• Higher throughput for faster data transfer

  
  

• Lower latency for real-time communication

  
  

• Increased reliability to ensure that critical safety messages are delivered promptly

The advancements brought by 5G-V2X will expand the potential for both current and future V2X use cases, further enhancing road safety, traffic flow, and vehicle automation.

Efficient Communication for Different Use Cases

The use of both direct and network communication modes enables C-V2X to allocate the most suitable method for each use case. For example:

• Fatal safety messages, e.g., emergency alerts, can be delivered through direct communication for immediate action

  
  

• Less urgent messages, like traffic updates or infotainment, can be transmitted via network communication

  
  

Commercial Services and Additional Benefits

The inclusion of cellular network usage in C-V2X also opens the door for commercial services from third-party providers. These services might include in-vehicle entertainment or remote diagnostics and vehicle monitoring. These additional services, available through cellular network providers, come at an extra cost but can offer significant value to consumers and fleet operators.

As C-V2X continues to evolve, it is poised to play a crucial role in the development of connected and autonomous vehicles, smart cities, and intelligent transportation systems (C-ITS). The ability to seamlessly connect vehicles, infrastructure, and pedestrians will lead to safer roads, more efficient transportation, and a greener future.

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 About Ettifos: 

Founded in 2018, Ettifos is a 5G-focused V2X solutions provider invested in enabling the most advanced smart city/smart intersection deployments and connected vehicles (CV) technology.

The company supplies innovative and versatile OBU and RSU systems tailored to customers’ specific project and service requirements, with the vision of connecting all entities in motion to create a world with safer, smarter, and more efficient roads.