The term „Vehicle to X Communication” (V2X) stands for the wireless exchange of information and data between vehicles and the environment. Thereby the X denotes diverse types of entities that are possible communication partners of a vehicle. These comprise other vehicles (V2V) as well as the complete environmental infrastructure (V2I) given by traffic lights, traffic signs or special road side units. The communication range of V2X lies between 300 and 1000 meters. Because of this relatively short range the type of communication is also called Dedicated Short Range Communication (DSRC). In order to communicate over greater distances the so called multi hop transmission is used which utilizes vehicles that are located between source and destination vehicle as routers. There are three main goals that are pursued by future V2X:
Increased traffic safety
Traffic flow optimization
Applicability of novel infotainment applications and services
To illusrate the beneficing of V2X in the case of point one “Increased traffic safety” an often mentioned example is the following: A vehicle breaks down in an unclear curve. It immediately transmits high priority warning messages to all subsequent vehicles. The drivers of the subsequent vehicles then are acoustically and visually informed and warned of the situation that is lying ahead.
In general, two types of messages are exchanged, so called Cooperative Awareness Messages (CAMs) which serve as a beacon that is sent regularly by all participating vehicles and contains basic safety relevant status information like the actual position, speed, acceleration, status of braking lights and so on. These messages are tranmitted with a frequency lying between two and ten Hertz. Beside the CAMs there exist the so called Decentralized Environmental Notification Messages (DENMs) which are used to inform other traffic participants of special events and conditions like roadwork constructions or accidents. They are sent as needed and not as a beacon.With the help of the CAMs and DENMs that are received from surrounding entities, each vehicle taking part in V2X, creates its own “Picture of Environment” by aggregating information. This picture is then the basis for a correct recognition of hazards.
Research activities within COMMputation focus on the development of a V2X communication system and its integration into an automotive E/E-Architecture. Also novel development techniques based on simulation are focus of research.