关键词: 车联网（IoV）, 多址接入, 安全应用消息, 时分多址（TDMA）

Abstract: In order to achieve the low latency and high reliability transmission of the safety application messages in the Internet of vehicles (IoV), this paper designs a QoS-oriented time division multiple access (TDMA) protocol. The protocol uses TDMA technique, and considers the transmission requirements of two kinds of safety application messages, cooperative awareness message (CAM) and decentralized environmental notification message (DENM), respectively. The combination of traffic simulation software SUMO and network simulation software OMNeT++ is used to build a vehicular network simulation platform—Veins, in which the relationship of traffic simulation and network simulation is bidirectional coupling and they can interact in real-time. The simulation of QoS-oriented TDMA protocol is implemented on the platform, and the performance is verified on it too. The simulation results show that the designed protocol does not improve the transmission reliability of CAM obviously, but improves the transmission reliability of DENM, and reduces the message transmission delay of both DENM and CAM. Compared with the IEEE 802.11p protocol, in the high speed scenario and the urban scenario respectively, the reception probability of the CAM in the QoS-oriented TDMA protocol is reduced by 5.8% and 7.1%, and the transmission delay of the CAM in the QoS-oriented TDMA protocol is reduced by 11.4% and 12.8%, the reception probability of the DENM in the QoS-oriented TDMA protocol is improved by 10.5% and 12.9%, and the transmission delay of the DENM in the QoS-oriented TDMA protocol is reduced by 13.3% and 15.1%.

Key words: Internet of vehicles (IoV), multiple access, safety application message, time division multiple access (TDMA)