Description
Date depot: 1 janvier 1900
Titre: Spatio-Temporal Relevance of Information for Local Information Dissemination in VANETs
Directeur de thèse:
Jérôme HÄERRI (Eurecom)
Domaine scientifique: Sciences et technologies de l'information et de la communication
Thématique CNRS : Non defini
Resumé:
After the huge success of passive safety systems and similar success indicators seen with recent advanced driver assistance systems towards a 'zero accidents' vision in future Intelligent Transport Systems (ITS), the next big potential is seen in cooperative systems. For this to become reality, a robust and reliable vehicle-to-vehicle and vehicle-to-roadside information exchange is a necessary prerequisite as an enabling technology. In Europe ETSI TCITS is paving the way towards this by standardizing the communication in
Vehicular Ad-hoc NETworks (VANETs).
The VANET communication architecture follows basically the layered
approach as proposed by ISO-OSI, with some additional vertical planes for cross layer information exchange. The most important layers for this thesis are the Medium Access Control (MAC) layer, the Facility layer and the applications. On the MAC layer, the basic access scheme is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), a probabilistic and thereby non-deterministic access technique. It is part of the ETSI ITS-G5 technology in Europe, which is based on IEEE 802.11p, an amendment of the Wireless Local Area Network (WLAN) specification adopted to VANETs. The interface between the applications and the communication part of the lower layers is realized by the facility layer. It is predominantly responsible for
the transmission of Cooperative Awareness Messages (CAMs) and Decen-
tralized Environmental Notification Messages (DNMs) and the associated
information aggregation. CAMs are broadcasted periodically and include
information about the status of the transmitting vehicle. They are used to create awareness for each vehicle and are the basic messages for multiple safety applications like Cooperative Adaptive Cruise Control (CACC) or Lane Change Warning (LCW). DNMs are event based messages, i.e. they are generated on an event and kept alive in a certain geographic area as long as the event is valid (geobroadcast). Safety applications based on DNMs are for instance Emergency Brakelight Warning (EBLW) and Road Hazard Warning (RHW). Independently, which type of messages are transmitted, the vehicles
in the immediate vicinity, either of other vehicles or event location, have to be informed quickly and reliably. As a result, how to perform a reliable and low-latency 1-hop broadcast is still an important research question within the VANET research community.
Doctorant.e: Kloiber Bernhard