Method and apparatus for controlling transmission power of a cognitive radio device

There are provided a method and apparatus for controlling transmission power of a CR device. The method includes detecting CR-environment information regarding a user's licensed or unlicensed user who occupies an adjacent channel or a neighbor cell, the CR device; determining a transmit power value of the CR-CR-device using the ambient information; and generating transmission power control information containing the transmission power value. The method and apparatus provide a reliable communication of the CR device safely and minimize the interference with the licensed user.