LTE ground-to-air measurements for UAV-assisted cellular networks

The concept of UAV-assisted cellular networks is quite new and has attracted the interest of researchers, and the telecommunications industry. The UAVs act as flying relays offering telecommunication services to underserved areas as well as providing an alternative data gateway in cases of overloaded base stations due to flash crowd situations. This paper provides representative field trial results from our two year measurement campaign with quadcopters, for different operational scenarios. The measured LTE signal strength and signal-to-interference-plus-noise ratio (SINR) in the air are studied in two different cases: a) an underserved rural area and b) the urban center of a town. In the first scenario high SINR values (>10 dB) are measured at certain altitudes allowing the extension of the network coverage. In the urban area, as the UAV ascends additional cells are detected affecting the SINR values, but also providing the means for macrodiversity.