Communication method for active and non-active carriers using carrier aggregation and an apparatus therefore

A base station configured to receive an uplink transmission from a user equipment configured with multiple downlink component carriers in a wireless communications system, the base station comprising:

• a radio frequency (RF) unit;
• and
• a processor configured to:
• transmit, to the user equipment, Radio Resource Control (RRC) configuration information for a channel status report, the RRC configuration information including information for periodically receiving the channel status report from the user equipment,
• transmit, to the user equipment, Layer 2 (L2) control information indicating states of the plurality of downlink component carriers, each of the plurality of downlink component carriers being indicated as one of an active state and a non-active state, and
• perform a procedure for periodically receiving the channel status report for a corresponding downlink component carrier from the user equipment in use of the RRC configuration information,
• wherein according to whether the corresponding downlink component carrier is in the active state or the non-active state at a time for receiving the channel status report, channel status information or no channel status information is received for the corresponding downlink component carrier from the user equipment at the time, respectively.