tailieunhanh - Car-to-Car Communication

Current average fuel economy levels vary consid- erably by country. Across the OECD the average figure in 2005 was around 8 litres per 100 km for new cars (including SUVs and minivans and in- cluding both gasoline and diesel vehicles). With a 50% fuel economy improvement, the average new car performance in OECD markets would improve to around 4 litres per 100 km (about 90 g/km of CO2). In the United States, fuel consumption is consid- erably higher than the OECD average: doubling of tested fuel economy would mean moving from the current new car (and light truck) average of 26 mpg to. | Car-to-Car Communication Stephan Eichler Christoph Schroth and Jorg Eberspacher Institute of Communication Networks Technische Universitat Munchen Munchen Germany Institute of Media and Communication Management SAP Research CEC University of St. Gallen Switzerland Abstract Car-to-car communication aims at increased driving comfort and safety. Moreover it changes the role of vehicles from mere transportation means to smart objects . Despite many R D activities in the last years this technology still poses multiple challenges on the wireless transmission and network protocols. Aspects like efficient message dissemination network scalability and information security mechanisms are still major research areas in the area of vehicular ad hoc networks. In this paper we present the potential of future car-to-car and car-to-environment communication systems introduce the major research challenges in this field and provide a selection of current research results. 1 Introduction and Motivation In the last couple of years communication between vehicles has attracted the interest of many researchers around the world 1 2 . In the European Union some research projects look into the potential of reducing road fatalities under the eSafety initiative . GST PreVent . The same is true in other countries like the USA or Japan. 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 .