Public LTE Network Measurements with Drones in Rural Environment

This paper presents long term evolution (LTE) uplink measurements taken with two drones operating in a public cellular network in rural environment. Three similar measurement scenarios with drone flight altitudes of 50~m and 100~m above ground level are studied with different measurement software and equipment. Four different key performance indicators (KPIs) are presented in the paper: Physical Resource Block (PRB) usage, Modulation and Coding Scheme (MCS) class, throughput and transmission power. These together help to analyse the overall interference behaviour, which is an essential part of the paper. The results show that aerial UEs add minor interference to the network, which decrease the MCS class of the ground level UEs and slightly increase their transmission power. The resulting data rates are roughly the same as them operating in the same cell because of increased PRB amount per user equipment (UE). This effect is similar to that of a ground level UE switching cell in the cell edge area to another cell. In addition, ground level cell edge area UE performs slightly poorer in comparison with a UE near the serving cell antenna when drones are utilized. Nevertheless, two drones operating in the air with smart phones connected to them do not have a critical effect on the performance of the normal ground level UEs from the throughput point of view, but slightly increase the resource utilization.