A method and a mobile station operating in a wireless communication system are described. Information on a primary carrier and one or more secondary carriers is received on a multi-carrier from a base station. Information on activation or deactivation of the one or more secondary carriers is received. The mobile station communicates with the base station via the primary carrier and one or more activated secondary carriers. Configuration information for power management is received that informs the mobile station of a first time period during which the mobile station monitors signals from the base station and of a second time period during which the mobile station does not monitor signals from the base station. When a specific indication is received from the base station, the mobile station stops the first time period and enters into the second time period.