Performance Evaluation Of VANET Oriented To Mobility

Vehicular Ad-hoc Network(VANET)technology is an important part of intelligent transportation system(ITS),with far-reaching significance.VANET is a mobile ad hoc network composed of on board unit(OBU)in the vehicle,road side unit(RSU),network control system in the Internet,and other wireless access devices in the actual traffic environment.VANET has great application value in ensuring traffic safety,improving traffic efficiency and enhancing entertainment through communication.Vehicle mobility has brought many important features to VANET.Research for mobility is an important breakthrough in performance bottlenecks.The high speed movement of the vehicle causes the communication node to move fast,the network topology changes fast,the communication link is short,the link is frequently connected and disconnected.The road conditions in which the vehicle travels limit the movement of the nodes,the speed,the start and stop,etc.,that is,restricted movement of nodes caused by traffic environment.For the following three reasons,the vehicle is operated by the driver,the vehicle is affected by leading vehicle,restricted movement factors,on the one hand the node movement can be predicted,on the other hand the node movement reflects complex human behavior.The impact of vehicle movement also includes rapid changes in the surrounding complex environment,which means that the wireless channel is subject to constant changes in the outside world.The real traffic environment is much more complex than the model description,and the more features of the vehicle mobility are to be excavated.VANET network performance evaluation and adjustment optimization has always been a hot research field,but there are few studies on the characteristics of vehicle mobility.The study of the influence of the generation rate of periodic beacons on broadcast receiving performance can provide theoretical basis for congestion control based on beacon generation rate.An empirical model takes the node transmit power as an independent variable,the packet reception rate is the dependent variable,can provide an empirical reference for dynamic power control to adjust network performance.A study examines the optimal values of competing windows at different relative velocities,is to find the appropriate competitive window dynamic adjustment strategy.Research on the impact of RSU distribution on network performance is to save resources while balancing network performance.But the research in this area is still in-depth,the shortcomings are simulation scene isn't real enough and factors aren't considered comprehensively.There are few studies on network performance evaluation for vehicle mobility.Most studies have stopped in the limited study of vehicle movement models.For the above reasons,this paper proposes four factors that restrict the movement of vehicular nodes: lane number,traffic light strategy,block size and road speed limit.A real urban traffic movement scenario is established.The influence of each mobile limited factor on the performance of VANET network is investigated by several simulation experiments.The regularity of the variable behavior of VANET network is analyzed.In order to study the restricted factors of node mobility,the influence of node density and packet transmission on network performance are investigated experimentally.The results show that the increase of the node density in the limited range can effectively improve the packet delivery rate,the packet delivery rate and the time delay decrease sharply with the increase of the packet rate.In the case of restricted movement experiment,when the number of nodes reach a certain number in the scene(600 vehicles in the range of 2000?2000 m),the impact of mobile limited factors on VANET network performance has the following performance: The greater the number of lanes,the greater the packet delivery rate;Duration of red light affects the degree of congestion.If the number of stagnation nodes indicates the degree of congestion,the packet delivery rate and the number of stagnation nodes are negatively correlated;The size of the block(also representing the length of the road)has a positive correlation with the packet delivery rate;Due to the follow-up behavior of vehicles in urban traffic,the packet delivery rate is almost unaffected by the road speed limit,and more affected by the vehicular node density.Oriented to the vehicle mobility,this paper proposes four restricted movement factors of vehicular nodes.The research results of VANET network performance evaluation can provide technical and theoretical reference for VANET network performance optimization and development direction.