In the last decade, Vehicular Ad hoc NETworks (VANETs) have attracted researchers, automotive companies and public governments, as a new communication technology to improve the safety of transportation systems aiming at offering smooth driving and safer roads. In this respect, a new Traffic Information System (TIS) has benefited from VANET services. The ultimate goal of a TIS consists in properly informing vehicles about road traffic conditions in order to reduce traffic jams and consequently CO2 emission while increasing the user comfort. To fulfil these goals, traffic information data or Floating Car data (FCD) must be efficiently exchanged between mobile vehicles by avoiding as far as possible the broadcast storm problem. In this respect, data aggregation appears as an interesting approach allowing to integrate FCD messages to generate a summary (or aggregate), which undoubtedly leads to reduce network traffic. We introduce, in this paper, a new data aggregation protocol, called Smart Directional Data Aggregation (SDDA). The main idea behind our SDDA protocol is to select the most pertinent FCD messages that must be aggregated. To this end, we rely on three filters: The first one is based on the vehicle’s directions. Indeed, every vehicle aggregates only FCD messages corresponding to its direction. Furthermore, it stores, carries and forwards uninteresting data. The second one is carried out by using road speed limitation. The third one relies on a suppression technique to remove duplicated FCD messages. Interestingly enough, our protocol works properly in both highway and urban conditions. The performed experiments show that SDDA outperforms the pioneering approaches of the literature in terms of effectiveness and efficiency.

中文翻译：

---

在VANET中实现更智能的定向数据聚合

在过去的十年中，车载专用网络（VANET）吸引了研究人员，汽车公司和公共政府，作为一种旨在改善交通系统安全性的新通信技术，旨在提供顺畅的驾驶和更安全的道路。在这方面，新的交通信息系统（TIS）已从VANET服务中受益。TIS的最终目标在于正确告知车辆道路交通状况，以减少交通拥堵，从而减少CO2排放，同时提高用户舒适度。为了实现这些目标，必须通过尽可能避免广播风暴问题来在移动车辆之间有效地交换交通信息数据或浮动汽车数据（FCD）。在这方面，数据聚合是一种有趣的方法，它允许集成FCD消息以生成摘要（或聚合），这无疑会减少网络流量。我们在本文中介绍了一种新的数据聚合协议，称为智能方向数据聚合（SDDA）。SDDA协议背后的主要思想是选择必须汇总的最相关的FCD消息。为此，我们依靠三个过滤器：第一个过滤器基于车辆的方向。实际上，每辆车仅汇总与其方向相对应的FCD消息。此外，它存储，携带和转发不感兴趣的数据。第二种是通过使用道路速度限制来执行的。第三个依靠抑制技术来删除重复的FCD消息。有趣的是，我们的协议可以在高速公路和城市条件下正常工作。进行的实验表明，SDDA在有效性和效率方面均优于文献的开创性方法。