A fundamental scalability criterion for data aggregation in VANETs

Abstract

The distribution of dynamic information from many sources to many destinations is a key challenge for VANET applications such as cooperative traffic information management or decentralized parking guidance systems. In order for these systems to remain scalable it has been proposed to aggregate the information within the network as it travels from the sources to the destinations. However, so far it has remained unclear by what amount the aggregation scheme needs to reduce the original data in order to be considered scalable. In this paper we prove formally that any suitable aggregation scheme must reduce the bandwidth at which information about an area at distance d is provided to the cars asymptotically faster than 1/d2. Furthermore, we constructively show that this bound is tight: for any arbitrary ε > 0, there exists a scalable aggregation scheme that reduces information asymptotically like l/d2+e. Copyright 2009 ACM.