On The Node Degree Of A Vehicular Ad-hoc Network

Vehicular Ad-hoc Netwok(VANET) is a specific application of Mobile Ad-hoc Network(MANET) and Wireless Sensor Network(WSN) in the field of Intelligence Transportation System(ITS). It can help to improve the driver`s judgement to the road and reduce their operating load by providing them with real-time traffic situation through ITS. While, to other aspect, the VANET plays an important role in energy saving and emission reduction by offering ITS users with a more safe, comfortable, economic and convenient traffic service.The VANET, consists of On Board Unit, Road Side Unit, Relay Backbone Network and Remote Management and Service Center, in which the attribute of nodes can affect the performance of the entire network to a great degree. To further understand the relationship between network and its behavior, lay a technique foundation of the vehicular network planning, we will carry out the research on the node degree property of the one-dimensional VANET. In this dissertation, we investigate some properties of nodes in the VANET, such as the node degree, hopcount and the distribution of node.The main work in this dissertation are the following aspects:Firstly, the paper will introduce the research background of VANET and some related concepts, the research on the status of VANET node are summarized as well.Then, we propose and validate a typical highway scenario of one-dimensional VANETs mobility model by combining the vehicular motions with topologies structure of VANET. The model, which consists of normal-speed and overtaking lane, uses both directions up and down the line to distinguish between left and right lane, is divided into two regions by the median zone. normal lane and passing lanes(left traveling direction). The vehicle trajectory data contains the instantaneous position of vehicle speed, acceleration, lane and any other information which can truly reflect the reality of the highway scene. We also use the two-ray ground reflection model as the radio propagation which based on the Large-scale fading.At last, through a combination of models and various theories, we derived the mathematical expressions of the expected node degree, hopcount and the distribution of the node degree, and conduct extensive experiment on the derived analytical results through NS2 simulator. We found that the experimental data is consistent with the theoretical data, which verify the theoretical derivation of this article.