Simulation of mobility models in vehicular ad hoc networks

One of the emerging applications that belongs to ambient systems is to transparently and directly interconnect vehicles in roads, making an ad hoc network that enables a variety of applications through distritbuted softwares without the need of any fixed and dedicated infrastructure. The network as well as the embedded computers and sensors in the vehicle will be invisible to the driver, who will get the required services during his journey. The most important kind of services are the ones related to his safety. Before Proceeding to the real implementation of any software or communication protocol in vehicular ad hoc networks (VANETs) it is mandatory to first evaluate it through a comprehensive simulation study. Mobility is an essential parameter that features VANET, and should be carefully considered in the evaluation. To get faithful and correct results in a simulation study, the mobility model should be as realistic as possible. The earlier models used in general mobile ad hoc networks (MANETs), such as the random waypoint, are unsuitable for the VANET application, where the movements cannot take place freely in the open area. Indeed, vehicles move on the existing routes, constrained by many parameters (route intersections, stop and traffic light signals, the presence of other vehicles in front the vehicle, etc.). Some new models taking into account these features have been recently proposed. In this paper we provide an overview of the mobility models newly proposed in literature, which can be used for simulating VANET. After that, we will present our mobility simulator that mimics many of the recent models. Finally, we use this simulator to illustrate the impact of the overtaking on mobility, a parameter ignored by all the previous simulation studies.