An Integrated Study on Mobility Models and Scalable Routing Protocols in VANETs

A vehicular ad hoc network (VANET) is a high mobility wireless ad hoc network that is targeted to support vehicular safety, traffic monitoring, and other commercial applications. Mobility models used in traditional mobile ad hoc networks cannot be directly applied to VANETs since real world factors such as road layouts and traffic regulations are not considered. In this paper, we propose a vehicular mobility model that reflects real world vehicle movement on the road. Based on the mobility, we study the performance of existing Mobile Ad Hoc network (MANET) routing protocols, i.e., AODV and GPSR. We observe the drawbacks of the MANET protocols and argue the inappropriateness of directly applying those MANET protocols to VANETs. We also propose simple modifications to these protocols which make them more suitable for small scale VANETs. When investigating the large scale VANETs, we introduce a two phase routing protocol that incorporates map information. The proposed protocol defines an overlay graph with roads of high vehicular density and forwards packet along the pre-calculated path in the overlay. The access, which is the rest areas relies on our modified small scale routing protocols to send packets to overlay . Both small and large scale routing protocols are validated with simulation. We generate vehicular mobility traces for different road layouts in Orlando by making vehicles follow the mobility model. We feed the traces to network simulators to study the routing behavior. Simulation results show the performance and effectiveness of our modified and proposed routing protocols for VANET scenarios.