基于雾计算的高速公路服务区内容访问技术研究

车联网(Vehicular Ad hoc Networks,VANETs)在高速公路上具有车辆高速行驶、密度低、通信基础设施稀缺、车辆连通性低等特点,使得高速公路上的车辆难以实现对其他车辆或路边单元(Road Side Unit,RSU)的内容访问。提出了一种在高速公路服务区利用雾计算以协助车辆获取感兴趣内容的模型。该车辆雾计算(Vehicle Fog Comput-ing, VFC)模型中,高速公路服务区收集来自各个地方的车辆提供的各种服务,将大量的停泊车辆和慢速行驶车辆作为雾设备。通过VFC本地化转发,不仅减少了通信延迟,还实现了令人满意的内容访问和实时数据流传输。此外,对通信能量消耗与系统延迟之间的关系进行公式化,并在雾计算中采用了外部近似(Outer Approximation,OA)算法来优化其权衡。仿真结果表明,通过采用雾计算和云计算结合的通信模式和均衡优化算法,随着能量消耗的增长,系统的通信延迟会明显地降低。

Research of the multi-way connectivity probability for platoon-based vehicle-to-infrastructure communication network

Vehicles travelling as platoons can reduce the huge traffic jams on the highway. Platoon members can share vehicle information such as speed and acceleration via vehicular ad hoc networks （VANETs） communication to maintain a constant inter-vehicle and inter-platoon distances. However, connectivity is a fundamental measurement to indicate the linking quality of VANETs. This paper analyzes the access and connectivity probability between the vehicles and the road side units （RSUs） of the multi-way platoon-based VANETs with roadside infrastructure. We denote the connectivity probability as the probability that the vehicles on the highway can access to at least one RSU besides the road within a designated number of hops. Moreover, besides considering the connection on the same road, we study the connection between the vehicles and the RSU via vehicles on the nearby neighbor roads. The analytical results have been validated by simulations and results show that the connectivity probability can be improved when there are platoons in a network. Meanwhile, the connectivity probability is higher in the multi-way vehicle-to-infrastructure （V2I） communication network than that in a one-way V2I communication network. The results in this paper can help to reduce the jams on the highway and achieve intelligent driving. Then the safety and comfort of the drivers and passengers on the highway can be improved. Moreover, these results can provide forceful theoretical support to the future intelligent transportation system （ITS） design.