Department of Information and Communication Engineering, DGIST, Daegu 42988, Korea.
Sensors (Basel). 2019 Oct 4;19(19):4306. doi: 10.3390/s19194306.
In the vehicular ad-hoc networks (VANETs), wireless access in vehicular environments (WAVE) as the core networking technology is suitable for supporting safety-critical applications, but it is difficult to guarantee its performance when transmitting non-safety data, especially high volumes of data, in a multi-hop manner. Therefore, to provide non-safety applications effectively and reliably for users, we propose a hybrid V2V communication system (HVCS) using hierarchical networking architecture: a centralized control model for the establishment of a fast connection and a local data propagation model for efficient and reliable transmissions. The centralized control model had the functionality of node discovery, local ad-hoc group (LAG) formation, a LAG owner (LAGO) determination, and LAG management. The local data propagation indicates that data are transmitted only within the LAG under the management of the LAGO. To support the end-to-end multi-hop transmission over V2V communication, vehicles outside the LAG employ the store and forward model. We designed three phases consisting of concise device discovery (CDD), concise provisioning (CP), and data transmission, so that the HVCS is highly efficient and robust on the hierarchical networking architecture. Under the centralized control, the phase of the CDD operates to improve connection establishment time, and the CP is to simplify operations required for security establishment. Our HVCS is implemented as a two-tier system using a traffic controller for centralized control using cellular networks and a smartphone for local data propagation over Wi-Fi Direct. The HVCS' performance was evaluated using Veins, and compared with WAVE in terms of throughput, connectivity, and quality of service (QoS). The effectiveness of the centralized control was demonstrated in comparative experiments with Wi-Fi Direct. The connection establishment time measured was only 0.95 s for the HVCS. In the case of video streaming services through the HVCS, about 98% of the events could be played over 16 frames per second. The throughput for the streaming data was between 74% to 81% when the vehicle density was over 50%. We demonstrated that the proposed system has high throughput and satisfies the QoS of streaming services even though the end-to-end delay is a bit longer when compared to that of WAVE.
在车对车自组织网络 (VANET) 中，作为核心网络技术的车载环境中的无线访问 (WAVE) 适用于支持安全关键应用，但在多跳方式下传输非安全数据时，很难保证其性能，尤其是在传输大量数据时。因此，为了有效地、可靠地为用户提供非安全应用，我们提出了一种使用分层网络架构的混合车对车通信系统 (HVCS)：一种用于快速连接建立的集中式控制模型和一种用于高效可靠传输的本地数据传播模型。集中式控制模型具有节点发现、本地临时组 (LAG) 形成、LAG 所有者 (LAGO) 确定和 LAG 管理功能。本地数据传播表示仅在 LAGO 的管理下在 LAG 内传输数据。为了支持 V2V 通信中的端到端多跳传输，LAG 之外的车辆采用存储转发模型。我们设计了包括简洁设备发现 (CDD)、简洁供应 (CP) 和数据传输在内的三个阶段，使得 HVCS 在分层网络架构上具有高效和稳健的特点。在集中式控制下，CDD 阶段的操作旨在提高连接建立时间，CP 阶段的操作旨在简化安全建立所需的操作。我们的 HVCS 实现为使用蜂窝网络进行集中控制的两级系统，使用交通控制器和使用 Wi-Fi Direct 进行本地数据传播的智能手机。使用 Veins 对 HVCS 的性能进行了评估，并与 WAVE 在吞吐量、连接性和服务质量 (QoS) 方面进行了比较。通过与 Wi-Fi Direct 的比较实验证明了集中控制的有效性。HVCS 的连接建立时间仅为 0.95 秒。在通过 HVCS 进行视频流服务的情况下，大约 98%的事件可以在每秒 16 帧以上播放。当车辆密度超过 50 时，流媒体数据的吞吐量在 74%到 81%之间。我们证明，即使与 WAVE 相比端到端延迟略长，所提出的系统也具有较高的吞吐量，并满足流媒体服务的 QoS。
