A Flight Route Design Method Considering Multi-Hop Communication Using Delivery UAVs

In recent years, the use of Unmanned Aerial Vehicles (UAVs) has been widely investigated, with particular attention to their potential applications within smart city initiatives. In urban areas, UAV-based delivery services are expected to help address the shortage of truck drivers while also contributing to the promotion of carbon neutrality. Furthermore, the use of multiple UAVs as a communication platform through multi-hop UAV relaying has been studied. UAV-based communication platforms are gaining attention as cost-effective solutions in regions where deploying terrestrial base stations is challenging, such as mountainous areas and remote islands, as well as in emergency situations like natural disasters. Among UAV-based communication platforms, multi-hop UAV relaying is attracting attention as an effective means. However, when employing multi-hop UAV relaying, challenges arise in scenarios where the distance between the source and destination is large, including increased costs due to the need for a larger number of UAVs and reduced throughput caused by the increase in hop count. To address these issues, this paper proposes a flight path design for UAVs in a multi-hop communication system utilizing delivery UAVs, aiming to improve throughput between destinations. The proposed method targets communication between a source and multiple destinations by strategically placing relay points (Way Points: WPs) along the flight paths. By routing UAVs through WPs, new communication links are established, enabling the direct construction of networks between destinations. This approach reduces the number of hops and ensures stable communication at a constant speed. For WP placement algorithms, we propose two methods: a centroid-based method and a shortest-communication-distance-based method. Simulation results demonstrate that the proposed approach enhances throughput.