Method and apparatus for contention technique using power control on ofdm system

A method for controlling power for lowering competition of mobile terminals in an OFDM(Orthogonal Frequency Division Multiplexing) system is provided to lower competition rate without allocating additional uplink resources when plural mobile terminals compete by controlling transmission power for signals transmitted from the mobile terminal to a base station. A method for controlling power for lowering competition of mobile terminals in an OFDM system comprises a receipt power acquiring unit(100), a transmission power information acquiring unit(200) and a transmission power determining unit(300). The receipt power acquiring unit acquires a size of receipt power when a mobile terminal receives cell broadcasting information broadcast by a base station. The transmission power information acquiring unit acquires information on transmission power included in the cell broadcasting information wherein the information on the transmission power is the information on the power when the cell broadcasting information is transmitted from the base station to the mobile terminal. The transmission power determining unit determines a size of the power on the basis of the acquired size of the receipt power and the information on the transmission power of the base station when the terminal transmits signals to the base station.