In this article, the performance of UAV-based mmW links is investigated when UAVs are equipped with square array antennas. The 3GPP antenna propagation patterns are used to model the square array antenna. It is shown that the square array antenna is sensitive to both horizontal and vertical angular vibrations of UAVs. In order to explore the relationship between the vibrations of UAVs and their antenna pattern, the UAV-based mmW channels are characterized by considering the large scale path loss, small scale fading along with antenna patterns as well as the random effect of UAVs’ angular vibrations. To enable effective performance analysis, tractable and closed-form statistical channel models are derived for aerial-to-aerial (A2A), ground-to-aerial (G2A), and aerial-to-ground (A2G) channels. The accuracy of analytical models is verified by employing Monte Carlo simulations. Analytical results are then used to study the effect of antenna pattern gain under different conditions for the UAVs’ angular vibrations for establishing reliable UAV-assisted mmW links in terms of achieving minimum outage probability. Simulation results show that the performance of UAV-based mmW links with directional antennas is largely dependent on the random fluctuations of hovering UAVs. Moreover, UAVs with higher antenna directivity gains achieve better performance at larger link length. However, for UAVs with lower stability, lower antenna directivity gains result in a more reliable communication link. Finally, based on the geometrical properties of a given region, we investigate the optimal antenna pattern along with the optimal aerial position for UAV relay to attain minimum outage probability.

中文翻译：

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无人机辅助毫米波链路的 3D 信道特性和性能分析

在本文中，研究了无人机配备方形阵列天线时基于无人机的毫米波链路的性能。3GPP 天线传播模式用于模拟方阵天线。结果表明，方形阵列天线对无人机的水平和垂直角振动都很敏感。为了探索无人机振动与其天线方向图之间的关系，基于无人机的毫米波信道的特点是考虑大尺度路径损耗、小尺度随天线方向图衰落以及无人机角振动的随机效应. 为了实现有效的性能分析，我们为空对空 (A2A)、地对空 (G2A) 和空对地 (A2G) 信道导出了易于处理的封闭形式的统计信道模型。分析模型的准确性通过采用蒙特卡罗模拟来验证。然后使用分析结果来研究不同条件下天线方向图增益对无人机角振动的影响，以建立可靠的无人机辅助毫米波链路，以实现最小中断概率。仿真结果表明，具有定向天线的基于无人机的毫米波链路的性能在很大程度上取决于悬停无人机的随机波动。此外，具有更高天线方向性增益的无人机在更大的链路长度上实现了更好的性能。然而，对于稳定性较低的无人机，较低的天线方向性增益会导致更可靠的通信链路。最后，基于给定区域的几何特性，