Car-to-X (C2X) is nothing but a means of communication that includes exchange of data and information between a vehicles and the transport infrastructure (C2I) or between vehicles (C2C/V2V). The basic goal is to give the driver an early and effective notice about any critical or dangerous situations along the road. Furthermore, increasing the traffic efficiency through a method of co-operative assistance. This type of communication is thus considered as the future of road transport throughout the world. In Europe, for example, there are different projects that essentially look to increase the safety in traffic as well as finding solutions to optimizing the road traffic. This is achieved by using C2X communication within the context of seeking applications with Intelligent Transport Systems (ITS). The information exchange takes place by a communication within the vehicle ad hoc networks (VANETs) on Dedicated Short Range Communication (DSRC). In Europe, the term ITS-G5 is used to avoid the confusion between the US and the Japanese version of DSRC ETS 12. The communicating nodes represent the ITS-S stations (ITS-S), where vehicles are referred to as Vehicle ITS-S and the infrastructure as Roadside ITS-S2 ETS-10a.
The infrastructure represents static road facilities and facilities on traffic routes that actively process and disseminate information. This is done by sending messages that can be received and expanded by the car. The car on the other hand processes the application data from the Adaptive Driver Assistance Systems (ADAS) and communicates with nodes in their environment. Car-2X communication thus represents the highly dynamic topology of the network which consists of short connection times, changing environmental conditions and directions of movement of vehicles. This forms the basis for the underlying communication system.
The C2X technology also offers new possibilities to enhance road traffic safety and traffic efficiency at a large scale. In figure 1.3, the car is seen to be able to connect with cars beyond its horizon. This extended horizon means the potential limit on the area of coverage for the communication can be effectively extended as a network. It can no longer be limited to the horizon of the camera active in the car. This involves the usage of Radar and Lidar technologies. With the help of these technologies, when a dangerous situation is detected along the road, the cars can send signals via hops. This allows the drivers behind to react on time and adapt their driving behavior accordingly.