The Research And Simulation Of VANETs Based On VanetMobiSim/NS-2

Nowadays, VANETs becomes hotspots of ITS field. The high mobility of vehicle will result in the frequent changes of network topology, the emergent buildings will also make wireless signal fade to some extent. There exists huge challenge in the VANETs research all the time, especially in the medium access control and reliable file transfer application. It has always been the focus of research on how to make information deliver timely and reliably in the vehicular environments.This thesis introduces the origin, structure and characters of VANETs, realizes both the MAC protocol 802.11p and filer transfer protocol VDTP in NS-2, then gives a detailed analysis of their implementation. The adopted mobility model of VANETs should reflect the true vehicular mobility trajectory. Therefore, we set up a highway scenario using VanetMobiSim, which is a microscopic traffic simulation software. This scenario simulates the vehicular node's mobility behavior seemingly. Then, we import the generated mobility trajectory into NS-2, in this way we realize the cross-platform simulation. Considering the particular channel fading environments in VANETs, we add probability channel fading model Nakagami into NS-2. As for the networking scenario, we configure the parameters in according to VDTP and 802.11p, meanwhile, combining TwoRayGround and Nakagami respectively. The simulation data show that VDTP is reliable in the communication of vehicular nodes, and we can also find that the vehicle moving in the same direction is the best choice for file transfer. Through adjusting transmission power and packet generation rate, we can find that the added capture function works well, and the different mechanism between deterministic and probability channel fading models can be seen clearly.As for simulation of protocol in the VANETs, fewer documents consider the channel fading environments, and many use the random node mobility model. In this thesis, we conduct the simulation on the basis of both channel fading model and the actual vehicular mobility model. This simulation measure approaches the reality, and the obtained data are more persuaded.