Research On Routing Algorithm In Vehicular Ad-hoc Networks

Vehicular Ad-hoc Networks(VANETs) that uses of road vehicles between vehicles and fixes roadside access points is an open self-organized structure Mobile Ad-hoc Networks (Mobile Ad-hoc networks, MANETs) to solve the problem of inter-vehicle communication. Traditional mobile self-organized networks route algorithms can not work effectively in VANETs due to its high node dynamics and network density dynamics and dynamic changes in network topology and the source nodes and destination nodes in different connected domains.To solve the above problems, this thesis addresses on routing algorithm for VANETs Networks according to its characteristics. To begin with, the technical background and some current typical applications of VANETs are introduced, then elaborated on the research status of the VANETs routing algorithm.On the basis of a brief analysis of the advantages and disadvantages of various types of routing algorithms, we sum up that the routing metric has been the gradual strengthening of the factors affecting routing performance considerations such as speed, distance, direction, but did not consider the impact of message size on the delay. Because mobile speed and direction of the routing metric not to consider delay and weight coefficients averaging failed to reflect the importance of different routing measures in the routing metric,we proposed a geographic routing algorithm based on message size and law entropy coefficient method. GRBME based on message size dynamically selects neighborhood vehicles with appropriate speed to complete a reliable data transmission, and by calculating the deviation angle of the neighbor vehicles to the destination node to select neighborhood vehicles with a small deviation angle to forward data,at the same time, using the method of entropy weight coefficient to determine each weight coefficient of the speed, distance, deviation from the direction of the three routing metrics. Algorithm ensures on the basis of that neighbors in the direction away from the destination closer and reliable message transmission,improve message delivery rate and throughput, while significantly reduces the delay.Then, for the VANETs intermittent connectivity, considering the traffic density, the data delay short-path data forwarding to reduce the delay, and the opportunity to network to carry forward thinking to ensure that data not be discarded in the low density of vehicles, thereby improving packet delivery ratio. Reference opportunity routing thought, we propose a adaptive opportunistic routing algorithm based on section of information perception.AORA calculates sections of the weight based on section information delay and the channel load of the sections at the intersection,then selects sections that has the smallest sections of the weight to forward data, while in the straight mode adaptively selects the improved greedy forwarding algorithm or carry forward algorithm, which effectively achieves fast data forwarding.In this paper, we choose the NS-2network simulation software as a simulation platform.This thesis simulates and evaluates our proposed routing algorithm to verify its effectiveness by setting different network simulation scenarios. The experimental results show that the proposed routing algorithms GRBME and AORA show good transmission performance in improving message delivery rate and decreasing transmission delay.