Outdoor Propagation Measurements for Drone Relay Systems - Drone Altitude Characteristics of Ricean K-Factor

Currently, mobile communication system using drones as relay stations has been considered in order to further increase the transmission speed in mobile communication system, to expand the service area, and to respond to the increase of localized traffic. However, the transmission characteristics of these systems in real propagation environments have not yet been fully clarified. In this paper, we evaluate the radio wave propagation characteristics in a drone relay system by the received power characteristics, drone altitude, presence of line-of-sight, and antenna directivity, based on the results of outdoor experiments using 5.12 GHz for the drone altitude characteristics of K-factor.