Unmanned-aerial-vehicle (UAV)-based communications are expected to play an important role in the future generation wireless communication networks. It is a promising solution to enhance the wireless connectivity of devices without infrastructure. As compared to the terrestrial communications, UAVs offer various advantages such as line-of-sight (LoS) connectivity, dynamic deployment and flexible reconfiguration. Further, free space optics (FSO) communication is considered as a possible solution to enable UAV-based communication links due to its cost effective and high bandwidth nature. However, despite offering large bandwidth, UAV-based FSO links are marred by atmospheric path loss, atmospheric turbulence, non-zero boresight pointing errors, and angle-of-arrival (AoA) fluctuations. In this paper, the performance of a hovering UAV-based FSO communication system is investigated. The closed-form expressions for outage probability, average symbol error rate (SER), and ergodic capacity are derived taking into account both heterodyne (HD) and direct detection (DD) techniques for ground-to-UAV (G2U), UAV-to-UAV (U2U), and UAV-to-ground (U2G) links over the generalized Málaga distribution. Moreover, the asymptotic expressions for the above performance metrics are also derived to get the diversity gain of the system.

中文翻译：

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无线 6G 时代展望


基于无人机（UAV）的通信预计将在下一代无线通信网络中发挥重要作用。这是一种很有前途的解决方案，可以增强无需基础设施的设备的无线连接。与地面通信相比，无人机具有视距（LoS）连接、动态部署和灵活重新配置等多种优势。此外，自由空间光学（FSO）通信因其成本效益和高带宽特性而被认为是实现基于无人机的通信链路的可能解决方案。然而，尽管提供了大带宽，基于无人机的 FSO 链路仍受到大气路径损耗、大气湍流、非零视轴指向误差和到达角 (AoA) 波动的影响。本文研究了基于悬停无人机的 FSO 通信系统的性能。考虑到地对无人机 (G2U)、无人机对无人机的外差 (HD) 和直接检测 (DD) 技术，导出了中断概率、平均误码率 (SER) 和遍历容量的封闭式表达式。 -广义马拉加分布上的无人机 (U2U) 和无人机对地 (U2G) 链路。此外，还推导了上述性能指标的渐近表达式，以获得系统的分集增益。