Car-to-car communication (C2CC), often referred to as vehicular ad hoc networks (VANETs), enables many new services for vehicles and creates numerous opportunities for safety improvements. Communication between vehicles can be used to realize driver support and active safety services like collision warning, up-to-date traffic and weather information or active navigation systems. However, besides enabling new services VANETs pose many challenges on technology, protocols, and security which increase the need for research in this field.

VANETs have similar characteristics as mobile ad hoc networks, often in the form of multi-hop networks. Due to the high mobility of nodes network topology changes occur frequently. All nodes share the same channel leading to congestion in very dense networks. The decentralized nature of VANETs leads to the need for new system concepts and information dissemination protocols. In addition, new approaches for data and communication security have to be designed to fit the specific network needs and to guarantee reliable and trustworthy services.

Technologies used for Vehicle-to-Vehicle Communication

  • Multiple-Access Wireless LAN Transmission to Vehicles – Many different wireless technologies are currently discussed to be used for car-to-car communication. Conventional IEEE 802.11p wireless LAN (WLAN), dedicated short range communication (DSRC), and GPRS/ UMTS are just some selected technologies.
  • Inter-vehicle Communication TechnologyVehicle-to-vehicle communication can be used to disseminate messages of multiple services generating their content using sensors within the vehicle. These services can include accident warning, information on traffic jams or warning of an approaching rescue vehicle. In addition, information on road or weather conditions can be exchanged. More elaborate inter-vehicle services are direct collision warning or intersection assistance with information on cross traffic.
  • Vehicle-2-Roadside Infrastructure Communication Technology – Communication between vehicles and road side units (RSUs) can also increase safety. Traffic lights or road signs could be equipped with a communication device to actively inform vehicles in the vicinity. Hence, drivers can receive information on traffic flow, road conditions or construction sites directly from the respective RSU. In addition, static hazard areas, e.g. construction sites, could be equipped with a RSU to warn surrounding vehicles. RSU-based services will play an important role during the introduction phase, since they are almost unaffected by the penetration rate.
  • Portal-based Vehicular Infotainment Technology – Besides the safety related services, many other services related to the vehicle or providing entertainment to the passengers can be brought to future vehicles. The on board unit (OBU) inside the vehicle collects all incoming messages and sensor information. In addition, it relies on a server-based infrastructure providing many additional services. These can include information on parking or hotels as well as sightseeing information.
  • Vehicular Business Communication Technology – vehicles will certainly play a major role in every day business processes that are currently handled by enterprise IT systems. Two different ways of integrating cars into business processes are considered valuable:
    • Vehicles transmit data such as geographical position, covered distance or average speed may be transmitted to a company’s backend system to allow for mobile asset management services. Logistics providers, for example, who nowadays run complex IT systems to manage their fleet, could feed real-time information into their applications to improve flexibility and adaptivity of their business processes.
    • Provisioning of car drivers with access to external data is a promising possibility of applying vehicular communications as well. Business people, which are always “on the move”, such as sales persons or consultants, may be highly interested in leveraging their cars’ onboard systems as a conventional workplace. Via speech input, drivers could trigger their cars to remotely access a company portal and to download crucial information for their next customer visit, for example.