The vehicular communications using Wireless Local Area Network (WLAN) technologies are initially intended for the safety relevant services, such as danger warning message dissemination and vehicle collision avoidance, in order to improve the travelling safety on highways. However, due to the adequate spectrum resource newly allocated to the Intelligent Transportation System (ITS) in the U.S. more and more non-safety relevant services, such as inter-vehicle entertainment, on board Internet access and high speed content download, are being studied under the context of Inter-Vehicle Communication (IVC) or Vehicular Ad-hoc NETworks (VANETs).
Introduction:The vehicular communications using Wireless Local Area Network (WLAN) technologies are initially intended for improving the road safety, e.g., to avoid potential vehicle collisions through Cooperative Collision Warning among vehicles. However, the development of wireless technologies and the recent spectrum allocation for Intelligent Transportation System (ITS) make it possible to support the non-safety infotainment services, such as on-road Internet access and inter-vehicle entertainments, in addition to the safety relevant services. More and more demands have been foreseen from the market in the near future on both safety and non-safety relevant services, which are all, based on Inter-Vehicle Communications (IVC) and Vehicular Ad-hoc NETworks (VANETs).
Standardization entities, such as the Dedicated Short Range Communications (DSRC) in the U.S., IEEE P1609 Working Group, IEEE 802.11 Task Group (TGp) and ETSI TG37 in Europe, are all working on standardization for the future vehicular communications worldwide. Cooperating with our industrial partner Philips, we are currently involved in the WILLWARN project, which is a subproject of the European PReVENT project. Besides, our ambition covers as well the IEEE standardization activities in TGp of 802.11 and IEEE P1609 version 2.
Due the high mobility nature of VANET, the traditional asynchronous and contention based IEEE 802.11 MAC can not work efficiently in a vehicular environment anymore. We have developed a novel solution, namely the Vehicular Wireless Media Network (VWMN), which is able to support the QoS of both safety relevant and non-safety relevant services through a synchronized and contention-free channel access scheme.
Challenges and potential topics:
The most interesting and challenging topics under the context of our research are listed below for diploma/master thesis work:
² Dynamic topology control is essential in high mobility VANET for network formation, service providing and channel access. We propose a distributed topology control scheme using intelligent beaconing and learning algorithms.
² Contention-free channel access schemes have advantages in channel access efficiency over contention based schemes like DCF/EDCA in IEEE 802.11. However, the performance of such schemes in high mobility vehicular environments is subject to evaluation.
² For the purpose of competing for the international standard, specifically IEEE 1609 version 2, efforts are still needed for enhancing and evaluating the compatibility of our solution with the old IEEE 1609 version 1 approach.
Tools used in our researches:
