Ultra‐wideband Channel Measurements and Modeling for Unmanned Aerial Vehicle‐to‐Wearables (UAV2W) Systems

The characterization of ultra‐wideband (UWB) wireless channel is very important to design any UWB system for health‐related applications. This chapter focuses on the fundamental properties of the UWB channel and presents one of the first experimental off‐body studies between a human subject and an unmanned aerial vehicle (UAV) at 7.5 GHz of bandwidth. The study was conducted in two environments: indoors and outdoors, and the human subject in this work was patched at nine different body locations under line‐of‐sight (LoS) conditions, four different body locations under non‐line‐of‐sight (NLoS), and at two body locations for four different body postures (sitting, sleeping, standing, and bending). The idea is to determine the best patch antenna location from the captured measurement data. Akaike Information Criteria (AIC) was used for statistical testing to find the distribution that best characterizes the fading channels between different body locations and the UAV. It was found that lognormal distribution fits the fading distribution the best. Detailed time dispersion analysis is also conducted for these nine body locations and four postures channels. In conclusion, the forehead was concluded to be the best location with minimum path loss and minimum delay among all the body channels, and among all the different postures.