Data Collection in Vehicular Networks

Vehicular Sensors Networks (VSNs) are an emerging paradigm in vehicular networks. This new technology uses different kind of sensing devices available in new vehicles, to gather information about the driver’s environment (speed, acceleration, temperature, seats occupations, etc.) in order to provide a safer, more 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 provider (WiMax access point, 2.5/3G base station) to combine non-valuable individual sensed data and extract from them effective feedbacks about the situation of the road in a geographical area (traffic density, unusual traffic behaviour, etc.). In operated VSNs, providers tend to reduce the traffic load on their network, using the free-frequency communication medium (IEEE 802.11p, for example). To do so, we propose CGP (Clustered Gathering Protocol), a cross layer protocol based on hierarchical and geographical data collection, aggregation and dissemination mechanisms. We analyze the performances of our solution using a simulation environment and realistic mobility models. We demonstrate the feasibility of such solution and show that CGP offers the operator precious information without overloading his network.