What does V2X stand for?
V2X stands for “Vehicle-to-everything” and refers to the wireless, real-time communication of a vehicle with any possible communication partner in its vicinity. Data transfer is possible in both directions, i.e. data originating from the vehicle and also from its surrounding environment. With V2X communication, it is possible to differentiate between communication between individual vehicles in road traffic (V2V – “Vehicle-to-Vehicle”), communication between a vehicle and pedestrians or cyclists (V2P – “Vehicle-to-Pedestrian”) and communication with intelligent infrastructure (V2I – “Vehicle-to-Infrastructure”). Intelligent infrastructure means, for example, intelligent crossings that record, process and circulate information about road users with the aid of installed cameras.
In German speaking countries, rather than V2X, the term C2X is used. C2X stands for “Car-to-everything”.
What is V2X used for and what are the benefits?
In addition to radar or LiDAR sensors and camera systems that already exist, communicating with the surrounding environment via V2X technology is an essential component in the vehicle’s perception of its surroundings. While sensor technology and cameras simply capture information in just one direction, V2X enables 360° communication with road users, traffic lights, construction sites and other items of infrastructure. This comprehensive information is paving the way towards the increasing autonomy of vehicles. In general, as a result of V2X technology, the safety of individual road users can be considerably increased by avoiding collisions. What’s more, thanks to real-time communication, information about traffic disruptions can be provided in advance, or recommendations can be given for alternative routes based on weather services, traffic cameras, constructions sites, traffic signs, etc. resulting in considerably improved traffic management with the associated increased energy efficiency and a reduced impact on the environment. Furthermore, with the aid of V2X, platooning can be used, particularly in long-distance truck transport. Platooning is where one driver controls several vehicles in close proximity to each other. In addition, thanks to V2X, cooperative driving is also possible where vehicles can adapt to their surrounding traffic conditions. For example, when overtaking a vehicle, the speed of the vehicle being overtaken automatically adapts so that it acts cooperatively with the vehicle behind.
In summary, the considerable advantages of V2X communication can be grouped into four categories:
- Safety – specific applications to reduce the frequency and seriousness of motor vehicle collisions by giving appropriate, timely warnings
- Comfort – specific applications to manage the condition of the vehicle
- Vulnerable Road User (VRU) – specific applications to improve interaction between vehicles and non-motorized road users
- Driver assistance systems (ADAS) – specific applications concerned with improving the volume of traffic, anticipating traffic signals, speed limits and weather warnings, etc.
How is V2X implemented and what are the basic requirements for this technology?
V2X communication can basically be implemented with the aid of a variety of possible technologies. However, the technology must be fail-safe, fast and as universal as possible. It must be possible to ensure data transfer, regardless of the type of communication (V2V, V2I, V2X), at all times without communication problems. To ensure this type of communication with any object, two leading technologies currently exist: DSRC (“Dedicated Short Range Communication”) and C-V2X (“Cellular Vehicle-to-X-Communication”). In addition to the corresponding technical advantages and disadvantages, the choice of technology is based on the region in which the vehicle is to be used (EU, USA, Japan) as well as on the personal preferences of the individual vehicle manufacturer. However, in recent years the trend has been shifting strongly towards the C-V2X approach.
What are the main differences between DSRC and C-V2X technologies?
DSRC is a WLAN system which is based on the IEEE 802.11p standard and has been tailored towards the requirements of automotive applications. The network basically operates in the 5.9 GHz spectrum with an effective communication range of approx. 1 km for Line-Of-Sight and 300 m for Non-Line-Of-Sight connections. C-V2X, on the other hand, embeds the latest mobile communication technologies into the vehicle’s environment. The network is operated in the 75 MHz spectrum whereby 5.9 GHz is provided for intelligent transport systems and other frequencies are used to increase network performance. This spectrum range is important because the signal propagation at 5.9 GHz covers shorter ranges and is more strongly affected by obstacles that inhibit high-frequencies. The most important prerequisites for the successful introduction of C-V2X are harmonization with more than 800 cellular providers throughout the entire world, the development of technology based on uniform standards, the development of 4G to 5G capabilities as well as simplified management through technology roadmaps for telecommunications standards within the 3GPP (Third Generation Partnership Project).
With DSRC, there is not yet a unified plan for the “next generation”.
C-V2X enables better connectivity, better robustness, greater range and higher energy efficiency or lower latency than DSRC. However, with C-V2X, the integration of a second LTE modem to separate safety-relevant communication from non-critical data traffic will be inevitable. Within the C-V2X approach, there are two basic transmission modes: Direct Access (Sidelink) and Vehicle-to-Network (V2N). Direct Access makes it possible for all types of vehicle and the infrastructure to communicate with each other independently of a cell phone network connection. V2N or C-V2N mode makes it possible for vehicles and the infrastructure to communicate with each other via the normal cell phone network, to provide virtually real-time information about road conditions and traffic. This mode can be useful for applications such as infotainment which do not have any safety-related requirements.