Signal transmission method for measurement used in handover of control and non-payload communication of unmanned aerial vehicle

Since one GRS used for Control and Non-Payload Communication (CNPC) of Unmanned Aerial Vehicle (UAV) cannot support all operational ranges of an UAV, the handover technology of CNPC is essential to operate an UAV in a wide range. However, the CNPC physical layer standard of Radio Technical Commission for Aeronautics (RTCA) does not have a reference signal for measuring the signal strength of a neighboring base station used for handover decision in an existing mobile communication system. Therefore, in this paper, we propose a method to transmit measurement signals for stable handover of CNPC. The proposed method starts transmission of the measurement signal when the UAV enters the handover zone for the preventing waste of power and generates the measurement signal using the same data that is transmitted through the currently connected Ground Radio Station (GRS) for the preventing packet loss during the handover operation.