Statistical Modeling of the FSO Fronthaul Channel for UAV-Based Communications
Statistical Modeling of the FSO Fronthaul Channel for UAV-Based Communications
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DOI：
10.1109/tcomm.2020.2981560
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发表时间：
2019-05
影响因子：
8.3
通讯作者：
M. Najafi;H. Ajam;V. Jamali;P. Diamantoulakis;G. Karagiannidis;R. Schober
中科院分区：
文献类型：
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作者：
M. Najafi;H. Ajam;V. Jamali;P. Diamantoulakis;G. Karagiannidis;R. Schober
在本文中，我们研究了悬停无人机（UAV）和中央单元之间的自由空间光学（FSO）通信通道的统计数据。两个独特的特性使得基于无人机的 FSO 系统与具有静态收发器的传统 FSO 系统显着不同。首先，对于基于无人机的 FSO 系统，入射激光束并不总是与接收器透镜平面正交。其次，由于动态风载荷、无人机周围大气中固有的随机空气波动以及无人机的内部振动，无人机的位置和方向都会随时间波动。相反，对于传统的FSO系统，激光束始终垂直于接收器透镜平面，并且收发器的相对运动受到限制。在本文中，我们通过量化相应的几何和失准损失（GML），同时考虑激光束的非正交性以及无人机位置和方向的随机波动，为基于无人机的 FSO 系统开发了一种新颖的通道模型。特别是，针对不同的天气条件，我们提出了不同的无人机位置和方向波动模型，并推导出相应的 GML 统计模型。我们进一步分析基于无人机的 FSO 链路在中断概率和遍历率方面的性能，并简化了高信噪比 (SNR) 状态的分析表达式。最后，仿真验证了所提出的分析的准确性，并为系统设计提供了重要的见解。例如，我们表明，对于给定的波动方差，应适当调整波束宽度以最小化中断概率。
In this paper, we investigate the statistics of the free space optics (FSO) communication channel between a hovering unmanned aerial vehicle (UAV) and a central unit. Two unique characteristics make UAV-based FSO systems significantly different from conventional FSO systems with static transceivers. First, for UAV-based FSO systems, the incident laser beam is not always orthogonal to the receiver lens plane. Second, both position and orientation of the UAV fluctuate over time due to dynamic wind load, inherent random air fluctuations in the atmosphere around the UAV, and internal vibrations of the UAV. On the contrary, for conventional FSO systems, the laser beam is always perpendicular to the receiver lens plane and the relative movement of the transceivers is limited. In this paper, we develop a novel channel model for UAV-based FSO systems by quantifying the corresponding geometric and misalignment losses (GML), while taking into account the non-orthogonality of the laser beam and the random fluctuations of the position and orientation of the UAV. In particular, for diverse weather conditions, we propose different fluctuation models for the position and orientation of the UAV and derive corresponding statistical models for the GML. We further analyze the performance of a UAV-based FSO link in terms of outage probability and ergodic rate and simplify the resulting analytical expressions for the high signal-to-noise ratio (SNR) regime. Finally, simulations validate the accuracy of the presented analysis and provide important insights for system design. For instance, we show that for a given variance of the fluctuations, the beam width should be properly adjusted to minimize the outage probability.