Research And Application Of Urban Road Emergency Message Transmission Mechanism Based On Internet Of Vehicles

With the rapid development of the city,the number of vehicles on the road is increasing and traffic problems are emerging.The development of Telematics plays an important role in relieving road congestion,improving travel efficiency,and development of intelligent urban roads.When traffic accidents occur on urban roads,a reliable emergency message transmission mechanism needs to be designed to transmit messages.Due to the complexity of urban road environment,brings certain challenges to the design of emergency message transmission scheme.This paper focuses on the characteristics of the urban road environment to carry out research work on emergency message transmission scheme,aiming to improve the efficiency and reliability of emergency message transmission.The main contents of this paper are as follows:(1)A probability-based emergency message broadcasting scheme is proposed.In the event of an accident,emergency messages need to be transmitted quickly to all affected vehicles in the vicinity.Since the transmission distance of vehicles is limited and the transmission distance of one hop cannot be transmitted to the predefined area,multi-hop broadcasting is usually used to transmit the emergency messages to the affected vehicles hop by hop through relay nodes.Due to the high-speed mobility of vehicles and the diversity of road layouts leading to constant changes in network topology,it becomes very difficult to select the appropriate relay node.To address these problems,the proposed scheme takes into account vehicle directionality,channel fading,and link stability to select the optimal relay node to forward emergency messages,and adds a suboptimal relay node selection mechanism to ensure the reliability of emergency message transmission.Region of Interest(ROI)is set in order to prevent the infinite proliferation of messages.The simulation results show that the proposed scheme has better performance in terms of delivery rate,end-to-end delay,number of forwarding hops,average number of conflicts,number of packet redundancies,and number of retransmissions.(2)A multi-hop broadcasting scheme for emergency messages based on bi-directional location prediction is proposed.In urban roads,vehicle movements are regular and predictable.Firstly,the proposed scheme improves the traditional greedy forwarding strategy,and then when performing vehicle node selection,the distance between the source node and the neighbor node predicted location,signal reception strength are calculated to determine whether the neighbor node has the conditions for optimal relay node selection.Finally,the selection of the relay node is performed based on the weight values between the distance of the source vehicle and the neighbor vehicle predicted position from the destination node,the angle between the neighbor node and the destination node,and the angle between the neighbor node predicted position and the destination node.Also,to improve the efficiency and accuracy of emergency message transmission,a Road Side Unit(RSU)is set at the intersection to participate in the broadcast of emergency messages.The simulation results show that the proposed scheme has better performance.(3)An accident warning system based on urban roads is designed.This accident warning system is designed to improve the congestion problem after an accident on urban roads.The accident warning is realized by the selection of RSU and the transmission of accident information,and finally the diversion of vehicles.