Routing mechanisms and cross-layer design for Vehicular Ad Hoc Networks: A survey

Vehicular Ad-Hoc Network (VANET) will pave the way to advance automotive safety and occupant convenience. The potential VANET applications present diverse requirements. VANET shows unique characteristics and presents a set of challenges. The proposed VANET applications demand reliable and proficient message dissemination techniques. Routing techniques proposed for Mobile Ad-Hoc Network (MANET) do not cater for the characteristics of VANET. The need for novel routing techniques, exclusively designed for VANET has been recognised. This paper analyses different routing techniques proposed specifically for VANET. Unique characteristics of VANET pose challenges to traditional layered architecture where different layers make independent decisions. Mobility, absence of global view of network, random changes in topology, poor link quality and varied channel conditions have encouraged the paradigm shift to cross-layer approach. In order to optimise the performance of VANET, architectures based on cross-layer approach have been proposed by the researchers. The paper also surveys such cross-layer paradigm based solutions for VANET and concludes with an analytical summary.