Patent ID: 8818440

Claim:
A method for controlling power of a base station participating in cooperative transmission in a Multiple Input Multiple Output (MIMO) wireless communication system, the method comprising: determining at least one beamforming matrix for processing transmission signals to terminals included in a terminal set for a multiple access by a plurality of base stations participating in cooperative transmission; determining minimum transmission power values for a minimum transmission rate of the terminals; determining total transmission power values for each of the base stations for a case of using the minimum transmission power according to a power gain by the beamforming matrix; determining whether each of the total transmission power values exceeds each of limit transmission powers of the plurality of the base stations; if the total transmission power values do not exceed all of the limit transmission powers, determining transmission power values for respective terminals in a range meeting the limit transmission power of the base stations; and if at least one of the total transmission power values exceed the limit transmission powers, removing one of: a terminal having a largest minimum power value, a terminal having a largest power gain through beamforming, and a terminal having a largest power that each base station allocates in order to satisfy a minimum transmission rate, from the terminal set, wherein the determining of the transmission power values comprises: determining a temporary power value of the terminal using a Lagrangian multiplier for a constraint condition for the limit transmission power, the beamforming matrix, and noise power experienced by a terminal; and determining a larger one of the temporary power value and a minimum power value of the terminal as a power value of the terminal.