A method is described for transmitting channel status information by a user equipment (UE) in a wireless communication system. A radio frequency (RF) signal is received from a plurality of downlink component carriers. Each downlink component carrier has a respective center frequency. A channel measurement result of at least one downlink component carrier from among the plurality of downlink component carriers is reported via an uplink. Downlink subframes available for measurement are contiguous on a downlink component carrier in an activated state. Downlink subframes available for measurement are non-contiguous on a downlink component carrier in a deactivated state.