Mobility models for vehicular ad hoc network simulations

• Authors: Niranjan Potnis;Atulya Mahajan
• Venue: Proceedings of the 44th annual Southeast regional conference
• Year: 2006

Considerable amount of research has been going on in the area of Vehicular Ad-Hoc networks (VANETS), where vehicles moving along streets in an urban city establish a network among themselves. There has been an increasing commercial and research interest in the development and deployment of such networks and the routing protocols used in these networks. Unfortunately the current state of the art mobility models for VANET simulations do not reproduce the characteristic movement of vehicles on the urban streets. They do not take into consideration the constrained movement of vehicles subject to street boundaries, stop signs, traffic lights and obstacles like buildings.Simulation is a very important tool for performance evaluation of ad-hoc networks. It enables us to conduct repeatable experiments under a controlled environment by isolating different parameters and varying them to study their affect on network performance. This would be highly costly and infeasible to accomplish in the real world. For close to accurate prediction of results, it is desirable that real world behavior is closely replicated while carrying out the simulations. The evaluation results need to be good predictors of protocol performance in the real world. The movement pattern of the nodes in the ad hoc networks is a factor that has a considerable impact on network performance. Mobility pattern is important in the sense that the position of nodes at any point of time, impacts the network connectivity which is central to the performance of the network. In this context, the mobility pattern of vehicles would play a crucial role in the performance evaluation of any VANET protocol done using simulations.Through this work, methods to capture the realistic mobility characteristics of vehicles on urban streets are proposed. These characteristics can then be used for carrying out more accurate simulations for VANETS. Two new simple mobility models that account for constrained movement patterns of vehicles on real world urban street maps are introduced. These two models incorporate the Stop Signs, Traffic Lights on the streets and interdependent motion of vehicles on same street. Also these traffic control mechanisms are enforced on real street maps available from US bureau database [2]. The mobility files generated by these models can be used by the network simulator ns2 [1] to carry out realistic simulations.