Routing of data in a vehicular ad hoc network is a challenging task due to the high dynamics of such a network. Recently, it was shown for the case of highway traffic that position-based routing approaches can very well deal with the high mobility of network nodes. However, baseline position-based routing has difficulties to handle two-dimensional scenarios with obstacles (buildings) and voids as it is the case for city scenarios. In this paper we analyze a position-based routing approach that makes use of the navigational systems of vehicles. By means of simulation we compare this approach with non-position-based ad hoc routing strategies (dynamic source routing and ad-hoc on-demand distance vector routing). The simulation makes use of highly realistic vehicle movement patterns derived from Daimler-Chrysler's Videlio traffic simulator. While DSR's performance is limited due to problems with scalability and handling mobility, both AODV and the position-based approach show good performances with the position-based approach outperforming AODV.

A routing strategy for vehicular ad hoc networks in city environments

Vehicles are part of people's life in modern society, into which more and more high-tech devices are integrated, and a common platform for inter-vehicle communication is necessary to realize an intelligent transportation system supporting safe driving, dynamic route scheduling, emergency message dissemination, and traffic condition monitoring. TrafficView, which is a part of the e-Road project, defines a framework to disseminate and gather information about the vehicles on the road. With such a system, vehicle's driver will be provided with road traffic information that helps driving in situations as foggy weather, or finding an optimal route in a trip several miles long. This paper describes the design and implementation of TrafficView and the different mechanisms used in the system.

TrafficView: traffic data dissemination using car-to-car communication

GeoSpray: A geographic routing protocol for vehicular delay-tolerant networks

VANETs (vehicular ad hoc networks) are emerging as a new network environment for intelligent transportation systems. Many of the applications built for VANETs will depend on the data push communication model, where information is disseminated to a group of vehicles. In this paper, we present a formal model of data dissemination in VANETs and study how VANET characteristics, specifically the bidirectional mobility on well defined paths, affects the performance of data dissemination. We study the data push model in the context of TrafficView, a system we have implemented to disseminate information about the vehicles on the road. Traffic data could be disseminated using vehicles moving on the same direction, vehicles moving in the opposite direction, or vehicles moving in both directions. Our analysis as well as simulation results show that dissemination using only vehicles in the opposite direction increases the data dissemination performance significantly.

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A Comparative Study of Data Dissemination Models for VANETs

Recent advances in wireless inter-vehicle communication systems enable the establishment of vehicular ad-hoc networks (VANET) and create significant opportunities for the deployment of a wide variety of applications and services to vehicles. In this work, we investigate the problem of developing services that can provide car drivers with time-sensitive information about traffic conditions and roadside facilities. We introduce the vehicular information transfer protocol (VITP), a location- aware, application-layer, communication protocol designed to support a distributed service infrastructure over vehicular ad- hoc networks. We describe the key design concepts of the VITP protocol and infrastructure. We provide an extensive simulation study of VITP performance on large-scale vehicular networks under realistic highway and city traffic conditions. Our results demonstrate the viability and effectiveness of VITP in providing location-aware services over VANETs.

Location-Aware Services over Vehicular Ad-Hoc Networks using Car-to-Car Communication

Because of its reactive nature, AODV can handle the highly-dynamic behavior of vehicular Ad-Hoc networks relatively efficiently. However, in addition to link status information, a lot of other information is available within cars, e.g. information about speed and location as well as digital maps. The realization of some of the envisioned application scenarios depends on the additional usage of this information. In this paper, we motivate the usage of GPS- and vehicle velocity data for geocast applications in the vehicular environment. We also describe the prototype that we are developing based on NIST-AODV [4].

Christian Schwingenschlogl

Papers

Geocast enhancements of AODV for vehicular networks