For emergency response scenarios like firefighting in urban environments, there is a need to both localize emergency responders inside the building and also support a high bandwidth communication link between the responders and a command-and-control center. The emergency networks for such scenarios can be established with the quick deployment of Unmanned Aerial Vehicles (UAVs). Further, the 3D mobility of UAVs can be leveraged to improve the quality of the wireless link by maneuvering them into advantageous locations. This has motivated recent propagation measurement campaigns to study low-altitude air-to-ground channels in both 5G-sub6 GHz and 5G-mmWave bands. In this paper, we develop a model for the link in a UAV-assisted emergency location and/or communication system. Specifically, given the importance of Line-of-Sight (LoS) links in localization as well as mmWave communication, we derive a closed-form expression for the LoS probability. This probability is parameterized by the UAV base station location, the size of the building, and the size of the window that offers the best propagation path. An expression for coverage probability is also derived. The LoS probability and coverage probabilities derived in this paper can be used to analyze the outdoor UAV-to-indoor propagation environment to determine optimal UAV positioning and the number of UAVs needed to achieve the desired performance of the emergency network.

翻译：针对城市消防等应急响应场景，既需要定位建筑内的应急响应人员，又需要支持响应人员与指挥控制中心之间的高带宽通信链路。通过快速部署无人机（UAV）可构建此类场景下的应急网络。此外，可利用无人机的三维移动性将其操控至有利位置，从而提升无线链路质量。这促使近期开展传播测量活动，以研究5G-sub6 GHz和5G-mmWave频段的低空空对地信道。本文针对无人机辅助应急定位和/或通信系统中的链路建立模型。具体而言，鉴于视线（LoS）链路在定位和毫米波通信中的重要性，我们推导出视线概率的闭式表达式。该概率由无人机基站位置、建筑尺寸以及提供最佳传播路径的窗户尺寸参数化。同时推导了覆盖概率的表达式。本文推导的视线概率和覆盖概率可用于分析室外无人机至室内传播环境，以确定最优无人机部署位置及实现应急网络预期性能所需的无人机数量。