Wireless networks consisting of low SWaP, FW-UAVs are used in many applications, such as monitoring, search and surveillance of inaccessible areas. A decentralized and autonomous approach ensures robustness to failures; the UAVs explore and sense within the area and forward their information, in a multihop manner, to nearby aerial gateway nodes. However, the unpredictable nature of the events, relatively high speed of UAVs, and dynamic UAV trajectories cause the network topology to change significantly over time, resulting in frequent route breaks. A holistic routing approach is needed to support multiple traffic flows in these networks to provide mobility- and congestion-aware, high-quality routes when needed, with low control and computational overheads, using the information collected in a distributed manner. Existing routing schemes do not address all the mentioned issues. We present a hybrid reactive routing protocol for decentralized UAV networks. Our scheme searches routes on-demand, monitors a region around the selected route (the pipe), and proactively switches to an alternative route before the current route's quality degrades below a threshold. We empirically evaluate the impact of pipe width and node density on our ability to find alternate high-quality routes within the pipe and the overhead required to maintain the pipe. Compared to existing reactive routing schemes, our approach achieves higher throughput and reduces the number of route discoveries, overhead, and resulting flow interruptions at different traffic loads, node densities and speeds. Despite having limited network topology information, and low overhead and route computation complexity, our proposed scheme achieves superior throughput to proactive optimized link state routing scheme at different network and traffic settings. We also evaluate the relative performance of reactive and proactive routing schemes.

翻译：由低SWaP、FW-UAV组成的无线网络被广泛应用于监测、搜索和监视难以进入的区域等场景。去中心化与自主化的方法确保了系统对故障的鲁棒性；无人机在区域内探索与感知，并以多跳方式将信息转发至附近的空中网关节点。然而，事件的不可预测性、无人机相对较高的速度以及动态的飞行轨迹导致网络拓扑随时间发生显著变化，从而引发频繁的路由中断。需要一种整体性的路由方法，以支持此类网络中的多流量传输，在必要时提供具备移动性与拥塞感知能力的高质量路由，同时利用分布式收集的信息实现较低的控制与计算开销。现有路由方案未能解决上述所有问题。本文提出一种用于去中心化无人机网络的混合反应式路由协议。该方案按需搜索路由，监控选定路由周围区域（即管道），并在当前路由质量降至阈值前主动切换至备用路由。我们通过实验评估了管道宽度与节点密度对在管道内寻找替代高质量路由的能力以及维持管道所需开销的影响。与现有反应式路由方案相比，本方案在不同流量负载、节点密度和速度条件下实现了更高的吞吐量，并减少了路由发现次数、开销及由此产生的流中断。尽管所获网络拓扑信息有限，且开销与路由计算复杂度较低，本方案在不同网络与流量设置下仍实现了优于主动式优化链路状态路由方案的吞吐量。本文亦对比评估了反应式与主动式路由方案的相对性能。