Handover Challenges for Cellular-Connected Drones

We report and discuss cell selection and handover measurements for an aerial drone connected to an LTE-A network in a suburban environment. Our experiments show how the handover frequency increases with increasing flight altitude: A drone flying at a typical height of 150 meters is expected to experience five cell changes per minute compared to only one change for ground users moving at the same speed. This behavior can be explained by the differences between ground and aerial devices in terms of cell selection. It is concluded that revised handover techniques and the consideration of drones in the planning and operation of 4G and 5G radio access networks are required.