Research On Accident Message Distribution Mechanism Of Internet Of Vehicles Based On V2X Cooperative Communication

The Internet of Vehicles(IoVs)is an important part of the Internet of Things in the field of intelligent transportation.Using IoVs technology to provide accident warning messages for vehicles is of great significance to reduce or avoid secondary accidents and improve traffic safety,and is one of the current research hotspots for IoVs applications.Due to the high speed of vehicles and frequent changes of vehicle positions on the highway,the channel conditions between vehicles are poor and the transmission is unstable,which makes the dissemination of accident warning messages face severe challenges.In addition,when disseminating accident videos as early warning messages,they can provide accident details that traditional text messages cannot provide,which has a better early warning effect.However,due to the large volume of video data and the sensitivity to transmission delay,how to transmit accident video data efficiently and reliably with low latency in the harsh environment of Internet of vehicles is the key and difficulty that restricts the development of video warning applications of Internet of vehicles.To address the above key issues,this thesis investigates the reliable transmission of accident video messages in IoVs.Introduce Scalable Video Coding(SVC)to encode the accident video and then transmit it,and studies the accident video message cooperative dissemination mechanisms that is applicable to the two scenarios: the accident scene is within the communication radius coverage of the roadside unit(RSU)and outside the communication radius coverage of RSU.The specific research contents of this thesis are as follows:1)Accident video message distribution mechanism based on V2 V cooperative communicationWhen the accident scene is outside the RSU communication coverage radius,using inter-vehicle cooperative communication to distribute accident videos for early warning.The accident vehicle uses SVC technology to encode the real-time recorded accident video and sequentially multicast it to vehicles within its communication range,with vehicles in the same and opposite lanes of the accident vehicle receiving the video message.Vehicles on the same direction lane are clustered and cooperate among the cluster,vehicles on the reverse lane perform relay elections and the successfully selected relay vehicles perform cooperative transmissions to vehicles in the same direction that are within their communication range.In the specific vehicle cooperation process,factors such as the position,speed,driving direction,channel conditions,video data reception and video decoding quality requirements of vehicles are comprehensively considered,and combined with instantly decodable network coding technology for encoding transmission to further improve accident video transmission performance.Simulation results show that the proposed cooperative transmission mechanism effectively shorten the transmission delay of accident video,increases the accident warning rate and improves the video reconstruction quality.2)Accident video message distribution mechanism based on V2 X cooperative hybrid communicationWhen the accident scene happens to be within the RSU’s communication coverage radius,RSU has stronger information processing capabilities and more stable data communication ability compared with vehicles,so a hybrid cooperative communication mode between RSU and vehicles is used to enhance the video early warning effect.When an accident occurs within the coverage of RSU,the accident video is recorded by the camera installed on the RSU,and at the same time it is SVC encoded and multicast.RSU schedules SVC video data according to the driving conditions and video receiving conditions of vehicles within its communication range.At the same time,the cooperative communication between the same direction vehicles and the reverse vehicles enables the vehicles that have not established a communication link with the RSU to receive the data,making full use of each cooperation opportunity to shorten video transmission delay.The introduction of instantly decodable network coding technology further reduces transmission delay and improves bandwidth utilization.Simulation results show that the proposed algorithm effectively improves the accident warning rate,shortens the accident message transmission delay,and improves the successful decoding rate of video while ensuring timely accidents warning to vehicles.