Digital Twin (DT) has revolutionized the contextualized digital environment. This advancement enables real-time monitoring and simulation of events, leading to more effective decision-making. In smart transportation, DT plays a crucial role in enhancing various aspects of road decision-making, including optimizing routing decisions for Emergency Message (EM) forwarding in Vehicular Ad hoc Networks (VANETs). In this study, DT has integrated with cutting-edge technologies such as Software-Defined-Network (SDN) and geographically distributed computing (fog computing) to elevate the position-based routing behavior in two directions: selecting the optimal next-hop and taking control of periodic messages (beacon transmission). The nature of routing decisions can be complex due to constant movement and frequent position changes of vehicles in the VANET system. Merely selecting the next-hop vehicle without considering its stability and predictability can result in suboptimal routing choices. To this end, SDN based on Reliable Emergency Message Routing Schema (SDN-REMR) is introduced. This schema utilizes DT and aims to leverage the behaviors of moving vehicles to enhance the delivery of EM by providing a reliable routing mechanism. To eliminate unstable neighbors from the list of potential next-hops, SDN-REMR forecasts the relative positions of surrounding vehicles using Euclidean distance and position information. Moreover, SDN-REMR uses the movement information collected from vehicles (such as position, speed, and power consumption) to reduce the possibility of a link disruption and select the best next-hop for reliable communication. SDN-REMR enables the Store-Carry-Forward (SCF) approach to ensure packets are successfully forwarded to the destination, even in challenging network conditions. This control strategy aims to strike a balance between maintaining reliable communication and minimizing congestion in the network. The experimental results prove that there are 42.6%, 76.22%, 76.22%, and 22.2% enhancement in terms of network throughput, total delivered packets, number of dropped packets, and routing overhead.

中文翻译：

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基于 SDN 的可靠紧急消息路由方案，使用数字孪生调整 VANET 中的信标传输


数字孪生 (DT) 彻底改变了情境化数字环境。这一进步可以实时监控和模拟事件，从而实现更有效的决策。在智能交通中，DT 在增强道路决策的各个方面发挥着至关重要的作用，包括优化车载自组织网络 (VANET) 中紧急消息 (EM) 转发的路由决策。在本研究中，DT与软件定义网络（SDN）和地理分布式计算（雾计算）等尖端技术相结合，从两个方向提升基于位置的路由行为：选择最佳下一跳并采取控制周期性消息（信标传输）。由于 VANET 系统中车辆的不断移动和频繁位置变化，路线决策的性质可能很复杂。仅仅选择下一跳车辆而不考虑其稳定性和可预测性可能会导致路由选择不理想。为此，引入了基于可靠紧急消息路由模式（SDN-REMR）的SDN。该模式利用 DT，旨在通过提供可靠的路由机制，利用移动车辆的行为来增强 EM 的交付。为了从潜在下一跳列表中消除不稳定的邻居，SDN-REMR 使用欧几里德距离和位置信息预测周围车辆的相对位置。此外，SDN-REMR利用从车辆收集的运动信息（例如位置、速度和功耗）来降低链路中断的可能性，并选择最佳的下一跳以实现可靠的通信。 SDN-REMR 支持存储传送转发 (SCF) 方法，以确保数据包成功转发到目的地，即使在具有挑战性的网络条件下也是如此。该控制策略旨在在维持可靠通信和最小化网络拥塞之间取得平衡。实验结果表明，网络吞吐量、总投递包数、丢包数和路由开销分别提高了42.6%、76.22%、76.22%和22.2%。