V2X (Vehicle to Everything) communications allows vehicles to interact with other vehicles, pedestrians, traffic signals, road signs, construction sites and other things in the environment. It is a foundation technology for autonomous driving, enhancing safety, efficiency and driving experience.

enables multiple communication modes:

• Vehicle-to-Vehicle (V2V): This allows vehicles to communicate with each other to share information about their speed, position, and direction. This can help prevent accidents by providing warnings about potential collisions or unsafe driving conditions.

• Vehicle-to-Infrastructure (V2I): Vehicles communicate with road infrastructure such as traffic lights, signs, and road sensors. This can optimize traffic flow and improve safety by providing real-time information about traffic conditions and upcoming signals.

• Vehicle-to-Pedestrian (V2P): This involves communication between vehicles and pedestrians, often through mobile devices or wearable technology. It aims to enhance safety for pedestrians by alerting drivers to their presence and vice versa.

• Vehicle-to-Network (V2N): This involves communication between vehicles and network services, including cloud-based systems. It enables access to real-time data and services such as navigation updates, weather conditions, and other information that can assist in driving.

• Vehicle-to-Device (V2D): This includes interactions between vehicles and various connected devices such as smartphones or smart home systems.

V2X technology is crucial for achieving full autonomous driving as it enhances the vehicle’s situational awareness beyond the capabilities of sensors like radar, camera and lidar. While those sensors are essential for detecting line-of-sight objects, V2X creates sensors that can detect objects without needing to be in direct line of sight with them. Moreover, V2X technology can work under all weather and lighting conditions, including rain, snow, low visibility, and when obstructed by impediments.

Currently, automakers and infrastructure developers around the world use two distinct V2X wireless communication technologies: Dedicated Short-Range Communication (DSRC) and Cellular-V2X (C-V2X). DSRC is an older technology that utilizes Wi-Fi within the 5.9GHz spectrum for communication, whereas CV2X is newer technology leverages cellular networks, including 5G for a more comprehensive communication ecosystem.

Dedicated Short-Range Communication (DSRC) is an IEEE 802.11p-based standard that operates in the 5.9GHz frequency band. It is built specifically for low-latency communication, typically within a range of 300m to 1,000m. DSRC has been under development for over two decades and is designed primarily for V2V and V2I communications.

One of the key strengths of DSRC is that it is a mature and well-established standard, with clearly defined protocols. Longevity has led to a high level of reliability and stability in its applications. Additionally, DSRC has built-in security and privacy mechanisms designed specifically for vehicular communication, offering strong protections with minimal computational overhead, making it efficient for in-vehicle systems. DSRC’s foundation on open standards further enhances its interoperability, allowing seamless communication across different vehicle manufacturers and infrastructure providers without being blocked into proprietary technologies. Moreover, DSRC is characterized by low latency, enabling real-time communication that is essential for safety-critical applications such as collision avoidance and emergency braking.

Despite these advantages, DSRC has some notable limitations. One of the primary challenges is its range and penetration in non-line-of-sight (NLOS) conditions. Buildings, terrain, and other obstacles can hinder the signal strength, making it less reliable in urban areas. Limited scalability is another concern, as DSRC operates in a fixed bandwidth spectrum, leading to potential performance degradation in dense traffic environments where many vehicles are trying to communicate simultaneously. Additionally, in many regions particularly in the U.S, the dedicated spectrum allocated for DSRC has been underutilized, leading to discussion about reallocating some of that spectrum for other purposes, which could affect the future of DSRC deployments.

In comparison, Cellular Vehicle-to-Everything (CV2X) is a more recent standard, based on 3rd Generation Partnership Project (3GPP) LTE and 5G cellular standards. C-V2X offers two communication modes: direct short-range communication (PC5 interface) and long-range cellular communications (Uu interface).

One of the key benefits of C-V2X is its range and coverage. Using the Uu interface, C-V2X can tap into existing cellular infrastructure, allowing it to cover much greater distances than DSRC, which is particularly advantageous for V2N applications like dynamic traffic management and over-the-air software updates. Additionally, C-V2X performs well in non-line-of-sight conditions, thanks to its advanced modulation and coding schemes, making it more reliable in urban environments filled with buildings and other obstacles. Another strength of C-V2X is its scalability. Since it operates over cellular networks, it can support a growing number of connected vehicles without running into the spectrum congestion issues faced by DSRC. Furthermore, forward compatibility with 5G enhances C-V2X’s future potential, enabling ultra-reliable low-latency communication (URLLC) and massive machine-type communication (mMTC), which opens doors for new V2X use cases as 5G networks expand.

However, C-V2X is not without its challenges. A key limitation is its network dependency. For V2N and other extended services, C-V2X relies on existing cellular infrastructure, which may be sparse or unreliable in rural and underserved regions, limiting its effectiveness in these areas. In addition, standards maturity remains a concern. C-V2X is still evolving, and while it shows promise, its full capabilities will only be realized with widespread 5G deployment, potentially leading to compatibility and deployment challenges in the interim. Lastly, regulatory and spectrum allocation issues could pose challenges. Unlike DSRC, which has dedicated spectrum, C-V2X must compete within the crowded cellular spectrum, though there is increasing regulatory support to allocate more bandwidth for V2X services.

While DSRC is a mature, proven technology, it faces limitations in term of range, scalability, and adaptability to new wireless standards. C-V2X, on the other hand, offers more flexibility, scalability, and future compatibility, particularly when combined with 5G. It provides better performance in non-line-of-sight conditions and can scale efficiency using existing cellular networks. As 5G networks expand, C-V2X is likely to become the dominant V2X technology, supporting a broader array of use cases, from safety-critical applications to infotainment and real-time traffic management.

In the ongoing debate between DSRC and C-V2X, C-V2X seems better positioned for the future of connected transportation, while DSRC remains a robust option for specific, highly localized V2X applications.

Testing of V2X

V2X technology in real-world environments faces significant challenges due to the inherent complexity of real-world conditions. Key issues include signal degradation and interference from various sources, which can compromise the reliability of V2X communication, particularly in urban areas with obstacles like buildings and traffic congestion. Additionally, V2X system must effectively handle a wide array of driving scenarios, making it difficult to simulate the millions of potential situations that vehicles encounter, such as varying traffic densities, weather conditions, and dynamic interactions with other road users. Furthermore, testing high-speed scenarios and dynamic mobility requires maintaining low latency and reliable communication, necessitating precise synchronization and robust data transmission between vehicles and infrastructure.

The cost of testing V2X system in real-world conditions can be prohibitively high, particularly for smaller manufacturers or ecosystem partners. Deploying test fleets, building test tracks and maintaining communication infrastructure require significant financial and logistical resources. For many V2X ecosystem partners, such as startups or Tier-2 suppliers the cost of testing can become a major barrier.

However, Keysight provides testing solutions for both type of V2X communications using laboratory-based simulators and emulators to tackle the challenges of testing in real-working environments. Additionally, we offer automated testing solutions to ensure that V2X system implementation comply with various test specifications. Our lab-based test beds effectively simulate or emulate real-world traffic scenarios, significantly minimizing the cost, complexity and time typically required for extensive field testing.

By: DocMemory
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