Research Of Accident Detect And Broadcast Scheme In Expressway Scenario Based On VANET

Expressway can apparently improve the traffic efficiency and relieve the urban traffic pressure compared with normal urban road.However,accident which happened on the expressway always caused higher probability of death and secondary accident,it is necessary to review the method of advanced accident detect and broadcast scheme.Considering that existed accident detect method,such as flooding,have disadvantages like always caused a high network load.Based on the VANET communication technology,this paper studied the accident detect method and the accident message broadcast scheme on expressway respectively.The main work of this paper includes:To begin with,defined the purpose and main functions module of the accident detect and broadcast system,on the basis of analyzed the DSRC infrastructure and key technology,constructed the framework and the application scenario of the accident detect and broadcast system based on VANET,explained the communication link type and the function of the communication entity in the system.Secondly,designed the database of the data storage unit and based on that,proposed a accident information collection scheme,then,by described the accident type and the accident happened procedure,came up with the vehicle approximate procedure judge method and the entire accident judge process.Besides,in the respect of scenario characteristic,analyzed the accident happened procedure,clarified vehicle nodes into two different types,proposed a network performance optimization processes in safe scenario and a node's role judgment and rebroadcast scheme in danger scenario,the whole accident message broadcast scheme is described as well.Finally,built a expressway simulation scenario using simulate platform Veins,test the rate of error warning and timeliness of the accident detect method,meanwhile,by comparing with the flooding broadcast,analyzed the transmit delay and output of the broadcast scheme.Experimental results revealed that the accident detect method has a high rate of accuracy and the time left when warning was triggered in simulation can give the driver enough time to take reaction;at the mean time,proposed broadcast scheme has lower transmit delay and lower output compared with the flooding broadcast scheme.