A cognitive radio communication system using a multiple input multiple output (MIMO) communication technology is provided. A cognitive radio base station includes a plurality of antennas, a group setting unit to set at least one sensing terminal group that includes at least one sensing terminal among a plurality of terminals, and a signal generator to generate a transmission signal to transmit the transmission signal using channels formed between the plurality antennas and the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time.