Aeronautical Ad-hoc Networks (AANETs) have been proposed as the promising complement to terrestrial networks for promoting the global interconnection to provide in-flight network service, emergency communication, vessel traffic service, etc. However, the large network scale of AANETs may induce severe synchronization overhead when the traditional topology-based networking algorithms are adopted. Moreover, the high-dynamic topology and changeable flight routes make the existing position-based routing algorithms suffer loop routing and forwarding failure. Motivated by these problems, this paper aims at developing efficient and low-cost networking and routing algorithms relying on the concept of dynamic virtual topology which organizes the disordered topology of AANETs into a structural and simplified one. The basic idea is that each connected aircraft is assigned with a unique and sequentially increased Virtual Identifier (VID) and thus all the connected aircrafts are organized into a virtual cluster consisting of one trunk and several branches. An event-driven synchronization mechanism is leveraged for maintaining the virtual topology as well as relieving the communication burden imposed by periodical broadcasting. By jointly considering the geographic locations and the virtual locations of aircrafts, we formulate the routing problem in AANETs as a weighted distance minimization problem, and further propose a novel routing algorithm, namely Trunk-Branch Cooperation aided Routing (TBCR) algorithm. Specifically, TBCR employs the geographic greedy forwarding strategy for enhancing its flexibility and boosts the routing efficiency by adopting the loop-free virtual topology based local forwarding. For extending the networking and routing algorithms to the global range, a multi-domain routing solution is also provided. Extensive experimental results show that the proposed Virtual Topology based Networking (VTN) cooperated with TBCR can reduce at least 30% average end-to-end transmission delay in large-scale AANETs and provide more than 90% lower synchronization overhead than the existing solutions.

中文翻译：

---

航空自组织网络的动态虚拟拓扑辅助网络和路由

航空 Ad-hoc 网络 (AANETs) 已被提出作为地面网络的有希望的补充，以促进全球互联，提供飞行网络服务、应急通信、船舶交通服务等。然而，AANETs 的大网络规模可能会导致采用传统的基于拓扑的组网算法时，同步开销很大。此外，高动态拓扑和多变的飞行路线使得现有的基于位置的路由算法遭受环路路由和转发失败。受这些问题的启发，本文旨在利用动态虚拟拓扑的概念开发高效、低成本的网络和路由算法，将AANETs的无序拓扑组织为结构化和简化的拓扑。基本思想是为每架连接的飞机分配一个唯一且顺序增加的虚拟标识符（VID），因此所有连接的飞机都被组织成一个由一个主干和几个分支组成的虚拟集群。利用事件驱动的同步机制来维护虚拟拓扑以及减轻定期广播带来的通信负担。通过综合考虑飞机的地理位置和虚拟位置，我们将AANETs中的路由问题表述为加权距离最小化问题，并进一步提出了一种新的路由算法，即主干-分支协作辅助路由（TBCR）算法。具体来说，TBCR 采用地理贪婪转发策略来增强其灵活性，并通过采用基于无环路虚拟拓扑的本地转发来提高路由效率。为了将网络和路由算法扩展到全球范围，还提供了多域路由解决方案。大量的实验结果表明，提出的基于虚拟拓扑的网络（VTN）与 TBCR 合作可以在大规模 AANET 中减少至少 30% 的平均端到端传输延迟，并提供比现有解决方案低 90% 以上的同步开销。