Research On Transmission Mechanism Of Safety Application Message In The Internet Of Vehicle

In recent years,the rapid development of intelligent transportation system has led to the continuous improvement of vehicular networking technology,which make the vehicular networking technology become a hot research topic in the field of intelligent transportation.In order to guarantee the safety of road traffic,safety application messages must be transmitted with low-latency and high reliability.Based on the analysis and summary of the existing works,a TDMA-based multiple access protocol is designed,which orients the quality of service(QoS)of safety application message,and takes the transmission requirements of cooperative awareness message(CAM)and decentralized environmental notification message(DENM)into account.The simulation results show that the designed protocol did not improve the transmission reliability of CAM obviously,but improved the transmission reliability of DENM,and reduced the message transmission delay of both DENM and CAM.Compared with the IEEE 802.11 p protocol,in the high speed scenario and the urban scenario respectively,the reception probability of the CAM in the QoS-oriented TDMA protocol has reduced by 5.8% and 7.1%,and the transmission delay of the CAM in the QoS-oriented TDMA protocol has reduced by 11.4% and 12.8%,the reception probability of the DENM in the QoS-oriented TDMA protocol has improved by 10.5% and 12.9%,and the transmission delay of the DENM in the QoS-oriented TDMA protocol has reduced by 13.3% and 15.1%.In order to make further efforts to realize the low latency and high reliability transmission of safety application messages,a network selection algorithm which based on DSRC/LTE and oriented the transmission of safety application message is designed.From the QoS demand of safety application messages,the designed algorithm considered various parameters such as end-to-end delay,packet loss rate and transmission speed.The simulation results show that the designed algorithm can allocate the network resource reasonably according to the different QoS needs of safety application messages.On one hand,compared with the QoS-oriented TDMA protocol,when use the QoS-oriented TDMA protocol and the designed algorithm simultaneously,in the high speed scenario and the urban scenario respectively,the reception probability of the safety application message has improved by 10.5% and 12.9%,and the transmission delay of the safety application message has reduced by 13.3% and 15.1%.On the other hand,compared with the matching game network selection algorithm in the high speed scenario and the urban scenario respectively,the reception probability of the safety application message in the designed algorithm has improved by 11.6% and 7.5%,and the transmission delay of the safety application message in the designed algorithm has reduced by 13.2% and 15.3%.