A communication device for an ultra-high-speed vehicle comprises a processor for performing a radio resource control function for communication between a first mobile device and the communication device, and a plurality of distributed antennas (DAs) positioned in a path of the first mobile device and transmitting or receiving a signal according to a control of the processor. The communication device also comprises a memory for storing at least one command executed by the processor. The at least one command is executed to configure a first sliding window including n DAs corresponding to a first position of the first mobile device, among the plurality of DAs, and perform communication with the first mobile device located at the first position by using the n DAs. Therefore, the performance of a communication system can be improved.