# Position-Monitoring-Based Hybrid Routing Protocol for 3D UAV-Based Networks
###### Abstract  
Unmanned aerial vehicles (UAV) have emerged as prime technologies due to their compatible size and flexible architecture. UAV technology offers services in vast application such as inter-UAV communication, wireless sensors, and the future Internet of Things (IoT) due to its compatible architecture. A UAV's speed varies while roaming, which may increase the risk of a connection failure. Various routing schemes have provided solutions to address this essential issue for three-dimensional (3D) UAV-based networks. The main category of UAV routing schemes is position-based routing schemes, which choose the best route based on the UAV's location. However, position-based routing has the drawback that it depends on exact positioning and tracking. An efficient routing scheme can resolve the significant issue associated with UAV mobility in a 3D environment. This paper aims to address the issues of static preloaded location values by presenting a hybrid routing scheme named the Position-Monitor-based Hybrid Routing Protocol (PMHRP), which takes advantage of both geographic and topology-based routing protocols. The PMHRP establishes the shortest possible route based on a UAV's Global Positioning System (GPS). Moreover, the proposed protocol utilizes the links for data forwarding. Furthermore, a disaster-based UAV scenario is adopted to provide connections to IoT devices. A detailed comparison analysis shows the proposed scheme's extreme performance and results in up to 65% to 73% better packet delivery ratio (PDR) than batch mark schemes under standard 3D UAV scenarios. Compared to earlier work, the proposed scheme reduces the average delay by up to 68% to 75%. Further proposed routing schemes offer 70% to 72% more throughput than the existing routing schemes, and NRL (%) is 42% to 49% lower than the existing routing schemes. This happens because of the global routing information available at each UAV which is provided by the position head coordinator (PHC) UAV in the proposed work. communication networks; centrality measure; routing protocols; 3D UAV networks +
Footnote †: journal:  
0000-0002-2000-0000-0000-0000-0000-0000-0000-00000-0000-00000-00000-00000-00000-00000-00000-00000-00000-000000-00000-00000-000000-000000-000000-000000-000000-000000-0000000-0000000-00000000-00000000000000000000 metropolitan cities, traffic monitoring in urban areas, natural disaster rescue operations, live streaming for events and many other critical applications. A UAV network is an infrastructure-less, self-organized, decentralized network, such as mobile ad-hoc networks (MANET) and vehicular ad-hoc networks (VANET), working in three-dimensional (3D) space. By employing the properties of MANETs and VANETs, UAVs can collect data from different places and transfer them to their destination by maintaining communication links [2]. Due to the presence of a 3D environment in UAV ad-hoc networks, it is essential to carefully consider UAVs' position, movement, and direction [3]. Therefore, to achieve better performance of UAVs in specific applications, different mobility models have been considered. The mobility models utilize mathematical models and simulation environments to offer realistic results scenarios for complex networks. Moreover, UAV ad-hoc network mobility is highly dynamic due to its movement in the air; on the other hand, MANET/VANET nodes move on specific paths, such as vehicles on the roads and streets. Hence, choosing an appropriate mobility model for a particular UAV ad-hoc network scenario is essential. In the below taxonomy, Figure 1 describes the classifications of mobility models. In contrast to the traditional MANET and VANET networks, the UAV-based network brings some new features and challenges, such as the fast movement of the UAVs in a sparse trajectory that makes maintaining communication links very challenging. One of the most challenging tasks is how UAVs can communicate while transmitting data. Therefore, high-speed mobility, stable connection, and 3D coordinates should be considered [4; 5].