SCORE: Data Scheduling at roadside units in vehicle ad hoc networks

Data Acquisition and delivery in Vehicular Ad hoc Networks (VANETs) is an important topic that has received very little attention. We proposed a system in which roadside units (RSUs) were exploited to satisfy the various requests of VANET users. Our approach uses RSUs as delegates to acquire services from service providers without the users connecting to them. Users´ interests range from email messages, news, web downloading, business transactions, multimedia sharing, traffic or weather information, etc... Depending on RSUs to obtain users´ data puts a huge load on the RSU network and might lead to a scalability problem, especially with the large number of users in VANETs. In this paper, we build on the approach and propose an RSU scheduling mechanism in which an RSU builds a schedule that is divided into time-slots (TSs). In each TS, all users that are expected to connect to the VANET are specified. Hence, an RSU prepares users´ data and caches them during a free TS before the users connect. The users´ connection times are derived from observing their actual connections. Our approach was tested using ns2 to assess its efficiency.