This paper investigates the use of unmanned aerial vehicles (UAVs)/drones for providing high data rates to mobile relays (MRs) placed on top of high speed train wagons, thus introducing the concept of Travel Hopping Enabled Resource Allocation (THEResA). The objective is to provide high data rate connectivity to train passengers in 5G+/6G networks. With the drone flying at the same train speed, highly directive beams can be formed and steered between the drone and each of the MRs. The simulation results in the paper show that this leads to high data rate connectivity, which will be reflected in the indoor links between the MRs and the train passengers inside the wagons. The drones maintain the connectivity to the cellular infrastructure by using high speed links with the cellular base stations (BSs) deployed along the rail track, e.g., through free space optics (FSO). The drones use the BS sites for recharging and resuming their operation. Therefore, a separate set of drones, or the same drones when they are not flying over trains, can be used to provide connectivity to remote rural areas. In fact, high speed trains might travel through rural areas with low population density. Although it is practical to lay fiber optic cables along the rail track, villages and small rural population agglomerations far from the railroad might not have access to the internet backhaul. UAVs can provide this connectivity in a delay tolerant fashion, by heading from the BSs/train station sites towards remote areas, collecting/transferring data from/to these areas, then returning to the sites along the rail track to recharge their batteries. This paper presents an analysis that shows the feasibility of this approach.

本文研究了使用无人驾驶飞行器 (UAV)/无人机为放置在高速火车车厢顶部的移动中继 (MR) 提供高数据速率的情况，从而引入了启用旅行跳跃的资源分配 (THEResA) 的概念。目标是为 5G+/6G 网络中的列车乘客提供高数据速率连接。当无人机以相同的列车速度飞行时，可以在无人机和每个 MR 之间形成和引导高度定向的波束。论文中的模拟结果表明，这会导致高数据速率连接，这将反映在 MR 与车厢内火车乘客之间的室内链接中。无人机通过使用与沿铁路轨道部署的蜂窝基站 (BS) 的高速链接来保持与蜂窝基础设施的连接，例如，通过自由空间光学（FSO）。无人机使用 BS 站点进行充电和恢复运行。因此，可以使用一组单独的无人机，或在不飞越火车时使用相同的无人机，为偏远农村地区提供连接。事实上，高速列车可能会穿越人口密度低的农村地区。尽管沿铁路轨道铺设光纤电缆是可行的，但远离铁路的村庄和农村小人口聚集地可能无法访问互联网回程。无人机可以以延迟容忍的方式提供这种连接，通过从基站/火车站站点前往偏远地区，从/向这些区域收集/传输数据，然后返回沿铁路轨道的站点为它们的电池充电。