Patent ID: 8600420

Claim:
A method for a base station of a mobile communication system to synchronize a subscriber station and an uplink time, the method comprising: performing an initial ranging with the subscriber station and establishing a fast fourier transform (FFT) interval based on delay time for delay transmission of uplink data caused by movement of the subscriber station, wherein a starting position of the FFT is prior to a starting position of a reference FFT interval as much as the delay time; generating initial ranging information including the delay time information and transmitting the initial ranging information to the subscriber station; and receiving the uplink data transmitted by using the delay time from the subscriber station, wherein the uplink data transmitted by the subscriber station approaching the base station are transmitted faster than the uplink data transmitted by the subscriber station when not moving, and the uplink data transmitted by the subscriber station leaving the base station are transmitted later than the uplink data transmitted by the subscriber station when not moving.