Apparatus and method for controlling power in wireless communication system using relay

An apparatus and a method for controlling power in a wireless communication system are provided to control idle mode and sleep mode of a mobile terminal. In case communications is not performed, a terminal(201) transmits the sleep require-message to the repeater station(203) in order to reduce the power loss(211). In case the sleep mode change over of the terminal is applied, the repeater station determines the management information in which the terminal operates to the sleep mode in consideration of the sleep mode management information which the terminal requests(213). The repeater station transmits the process time delay information of the sleep mode management information of the terminal and repeater station are transmitted to the base station(215). The base station transmits the sleep administration response message to the repeater station if the sleep management message is received without error(217).