Statistical Characteristics of Excess Loss for UAV-to-Indoor Propagation Channel

Air-to-ground (A2G) communication has attracted lots of attention driven by the demand for upcoming air-and-ground integrated networks. While existing A2G communication researches primarily focus on outdoor users as terrestrial terminals, it is crucial to acknowledge the essential role played by indoor users in real-world scenarios. For this purpose, we conducted a channel measurement campaign at 5 GHz band, specifically targeting the unmanned aerial vehicle (UAV)-to-indoor (U2I) communication. We investigate the excess loss (EL) relating to large-scale fading in U2I channels. To study the EL variations across different indoor environment, we focus on two general micro scenarios, namely glass window room and indoor corridor. Given the fact that the measured EL results in two scenarios exhibit significant difference, we provide the corresponding elevation-dependent EL median model, respectively. On the other hand, we also study the impact of the UAV flight altitude on EL. In this work, experimental data are collected from different buildings to avoid establishing the site-specific model. By examining the fading in different scenarios and altitudes, this work can provide valuable insights for the design and evaluation of U2I communications.