Research On VANET Routing Algorithm Based On Traffic Flow Characteristics In Urban Environment

In order to solve the increasingly serious traffic problems at present,improve the efficiency of traffic travel,and increase the safety and comfort of drivers,China is actively promoting the development of intelligent transportation system ITS,and VANETs technology is the focus of ITS research.This paper mainly studies the routing protocol in VANET technology in urban environment.Combining the characteristics of VANET in urban environment and the characteristic parameters of traffic flow,based on the research and analysis of the existing routing protocol,the paper makes improvements in the direction that is more suitable for VANET in urban environment.The main work of this paper is divided into the following aspects:(1)Study the vehicle micro movement model of VANET in urban environment.An improved model IVMFM was proposed to optimize Krauss model for the unification of speed mutation behavior and driver driving behavior.By introducing driver reaction time and acceleration variables subject to truncated Gaussian distribution,the difference of driving behavior of different individuals was reflected.Improve vehicle safety speed,give certain acceleration change rate,and optimize acceleration abrupt change behavior.Based on the IVMFM model,the vehicle movement trajectory under the street area map of Shanghai Songjiang University Town generated by the SUMO platform is used to build the traffic scene for the experimental simulation of routing protocol.(2)The characteristics of vehicle flow trajectory and existing routing protocols under urban environment were studied.Aiming at the problems of poor data forwarding performance,frequent routing interruptions and poor adaptability of VANET routing protocol under current urban environment,an improved routing algorithm TCR was proposed.TCR predicts the connectivity between road segments through real-time traffic density information.Combined with the distribution of vehicles,it selects the appropriate sections for data forwarding to minimize the local extreme probability of vehicles and improve the stability of the link.In the straight section,based on the optimized greedy forwarding strategy,considering the location,distance,direction and link quality of the next hop node and the destination node,the priority is assigned through the weight coefficient to select the most appropriate relay node.The routing repair strategy considers the secondary node selection and improves the store-and-forward strategy to improve routing adaptability and data forwarding performance.(3)The vehicle movement trajectory generated by SUMO was imported into NS2.Through the comparison of AODV,GPSR and TCR routing experiments,the results show that TCR algorithm is superior to the other two routing algorithms in terms of data transmission success rate and average end-to-end delay,and TCR algorithm can better adapt to the communication requirements of VANET in urban environment.