A method is presented for a mobile station operating in a wireless communication system. The mobile station receives configuration information for power management from a base station. The configuration information informs the mobile station a first time period during which the mobile station monitors signals from the base station and a second time period during which the mobile station does not monitor signals from the base station. The mobile station applies the configuration information for power management to one or more primary carriers and one or more activated secondary carriers. The mobile station receives downlink data from the base station via the one or more primary carriers and the one or more activated secondary carriers during the first time period. The mobile station receives a specific Medium Access Control (MAC) message from the base station, wherein the mobile station stops the first time period when receiving the specific MAC message.