Studies On Routing Algorithm For Vehicle Networking In Urban Scene

In the urban environment,the complex and changeable traffic conditions have a great impact on the routing of information transmission between vehicles.Therefore,research on VANET routing algorithms suitable for urban environments has received extensive attention.This thesis focuses on the issues of the unreliable information transmission caused by insufficiently considering the impact of the road on the information transmission and the ability to receive and process the information,in the cases of sparse and dense density,respectively.The main work has the following two aspects:(1)Under the condition of sparse vehicle density,aiming at the problem of the unstable vehicle connectivity and the unreliable information transmission in the transmission road,an ant colony optimization VANET routing algorithm based on link quality is studied to construct the transmission road optimization section between the source vehicle and the destination vehicle.The algorithm establishes a mathematical model by analyzing the connectivity probability,transmission delay and packet delivery rate of the current road to evaluate the link quality of the current transmission road.In addition,to obtain the optimal information transmission path,an improved segment selection formula of ant colony algorithm is proposed by introducing local link quality and global link quality.The simulation results show that the proposed algorithm can reduce the convergence speed,packet transmission delay and improve the information packet delivery rate.(2)Under the condition of dense vehicles,aiming at the problem of information delay and backlog caused by the sudden and random of information transmission and the limited service capacity of vehicles,a VANET routing algorithm based on stochastic network calculus is proposed to build a scene where multiple relay vehicles transmit vehicle information from the source vehicle to the destination vehicle.The algorithm model the vehicle connection time prediction by analyzing the relative speed of the vehicle,the initial spacing,the remaining communication distance,the Poisson distribution,and the normal distribution to obtain a candidate relay vehicle set.At the same time,the machine arrival curve and the stochastic strict service curve model are established based on the random network calculus method to analyze the delay and backlog in the process of information transmission between vehicles.The simulation results show that the algorithm is superior in transmission delay and backlog.