Data Collection in Vehicular Networks

Vehicular Sensors Networks (VSNs) are an emerging p aradigm in vehicular networks. This new technology uses different kind of sensing devices available in new vehicles, to gathe r information about the driver’s environment (speed, acceleration, temperature, seats occupations, etc.) in order to provide a safer, mor e efficient and more comfortable driving experience . In this paper, we focus on a particular VSN architecture, where the ad hoc network is operated by a telecommunication/service provi der (WiMax access point, 2.5/3G base station) to combine non-valuable indivi dual sensed data and extract from them effective fe edbacks about the situation of the road in a geographical area (traffic density, unusu al traffic behaviour, etc.). In operated VSNs, providers tend to reduce the traffic load on their network, using the free-frequency communic ation medium (IEEE 802.11p, for example). To do so, we propose CGP (Clustered Gathering Protocol), a cross layer protocol based o n hierarchical and geographical data collection, agregation and dissemination mechanisms. We analyze the performances of our solu tion using a simulation environment and realistic mobility models. We demonstrate the feasibility of such solution and sh ow that CGP offers the operator precious information without overloading his network.