We consider free-space optical (FSO) communication links for the backhaul connectivity of small cells (SCs) where a UAV with an FSO apparatus can serve as a backhaul relay node. We demonstrate how such drone relay stations (DRSs) can be deployed in a high-rise urban area in order to provide FSO line-of-sight (LOS) links that are unobstructed by buildings. Also, in our solution we consider the case where solar panels are mounted on DRSs such that placing the DRS in a sunny location is prioritized, and we show the gain in terms of number of required trips to recharge the UAV.

翻译：我们考虑为小型细胞(SCs)的回航连接提供自由空间光学通信连接,配备FSO设备的无人驾驶飞行器可以作为回航中继节点,我们演示如何在高楼城市地区部署这种无人机中继站,以便提供建筑物不受建筑物阻碍的FSO视线连接。此外,在我们的解决方案中,我们考虑了太阳能电池板安装在DRS系统上的情况,以便优先将DRS安装在阳光明媚的地点,我们显示了为补充UAV所需旅行次数的增加。