Abstract: A MAC layer dynamic priority scheduling mechanism according to the features of vehicles in expressway DSRC scene is proposed. Different priority level is given to messages according to the emergency degree and different priority is determined by the function of parameters of time, distance and direction. Absolute priority is introduced to ensure smooth communication of emergency vehicles, then according tothe features of expressway, safety information attributeda parameter of direction. The experimental results show that, compared with the traditional mechanism, the mechanism proposed in this paper can significantly reduce the network load and improve the resource utilization.

Key words: Dedicated Short Range Communications（DSRC）, dynamic priority, IEEE 802.11p, safety information

摘要： 在高速公路的DSRC场景下，根据车辆行驶特性提出一种MAC层动态优先级的调度机制。根据消息的紧急程度来赋予不同的优先级，建立含有时间、距离、方向等参数的函数来确定不同优先级。引入绝对优先级以保证紧急救援车辆的顺畅通信，再针对高速公路双向行驶的特点，将安全信息赋予方向的属性。实验结果表明，相比传统的机制，提出的机制可有效降低网络负载、提高网络资源利用率。

关键词: 专用短程通信技术（DSRC）, 动态优先级, IEEE 802.11p, 安全消息