The use of unmanned aerial vehicles (UAVs) is attracting considerable interest in academic research, commercial, and military applications. Multi-UAV systems organized in an ad hoc fashion called a flying ad hoc network (FANET) can cooperatively and collaboratively accomplish complex missions more efficiently compared to single large UAV systems. However, the unique features of FANETs such as high mobility, low node density, and high frequency of topology changes introduce challenges to the communication design, especially routing. Thus, the routing requirements of FANETs surpass those of MANETs or VANETs. In this paper, we present UAV classification, communication and application architectures, and an exhaustive survey of the existing routing protocols for flying ad hoc networks. Furthermore, we highlight the key features, strengths and weaknesses, and different mobility models used for the performance evaluation of the existing FANET routing protocols. More importantly, a proposed taxonomy and a review on the existing FANET routing protocols are presented. Finally, we highlight the existing challenges and open research issues.

中文翻译：

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Flying Ad Hoc 网络中的路由：综合调查

无人机 (UAV) 的使用引起了学术研究、商业和军事应用的极大兴趣。与单个大型无人机系统相比，以一种称为飞行自组织网络 (FANET) 的自组织方式组织的多无人机系统可以更有效地协作和协作完成复杂的任务。然而，FANETs 的独特特性，如高移动性、低节点密度和拓扑变化频率高，给通信设计，尤其是路由设计带来了挑战。因此，FANET 的路由要求超过了 MANET 或 VANET。在本文中，我们介绍了无人机分类、通信和应用架构，并对现有的飞行自组织网络路由协议进行了详尽的调查。此外，我们强调了主要特点，优点和缺点，以及用于评估现有 FANET 路由协议性能的不同移动模型。更重要的是，提出了对现有 FANET 路由协议的拟议分类和审查。最后，我们强调了现有的挑战和开放的研究问题。