Communication Method Using a Carrier Aggregation and Apparatus Therefore

1. A method of controlling uplink transmission at a user equipment in a wireless communications system, wherein the user equipment is configured with multiple uplink component carriers including a first uplink component carrier and a second uplink component carrier, the method comprising: receiving, from a base station, Radio Resource Control (RRC) configuration information for a Sounding Reference Signal (SRS), the RRC configuration information including information for periodically transmitting the SRS to the base station; and performing a procedure for periodically transmitting the SRS to the base station on an uplink component carrier of the multiple uplink component carriers in use of the RRC configuration information, wherein an SRS transmission is performed on the uplink component carrier at a time for transmitting the SRS when the uplink component carrier is in an active state at the time for transmitting the SRS, and the uplink component carrier is configured to allow an uplink signal transmission in the active state, wherein the SRS transmission is skipped on the uplink component carrier at a time for transmitting the SRS when the uplink component carrier is in a non-active state at the time for transmitting the SRS, and the uplink component carrier is configured not to allow an uplink signal transmission in the non-active state, wherein a first downlink component carrier is paired with the first uplink component carrier, and the first downlink and uplink component carriers are always in the active state, and wherein the active/non-active states of the second uplink component carrier using Layer 2 (L2) control signaling, and the second uplink component carrier and a second downlink component carrier paired with the second uplink component carrier have a same state among the active/non-active states.

2. The method of claim 1 , wherein the second uplink component carrier is in the non-active state, when multiple downlink component carriers paired with the second uplink component carrier are all in the non-active state.

3. The method of claim 1 , wherein information for the second downlink component carrier and the second uplink component carrier is configured by using RRC signaling, and active/non-active states of the second uplink component carrier are controlled by using the L2 control signaling based on the information configured by the RRC signaling.

4. A user equipment configured to communicate with a base station using multiple uplink component carriers including a first uplink component carrier and a second plink component carrier in a wireless communications system, the user equipment comprising: a radio frequency (RF) unit configured to transmit and receive wireless signals to and from the base station; a memory configured to store information being transmitted and received to and from the base station and parameters required for performing operations of the user equipment; and a processor configured to be connected to the RF unit and the memory, and configured to control the RF unit and the memory, so as to operate the user equipment, wherein the processor is configured to receive, from a base station, Radio Resource Control (RRC) configuration information for a Sounding Reference Signal (SRS), the RRC configuration information including information for periodically transmitting the SRS to the base station, and to perform a procedure for periodically transmitting the SRS to the base station on a uplink component carrier of the multiple uplink component carriers in use of the RRC configuration information, wherein an SRS transmission is performed on the uplink component carrier at a time for transmitting the SRS when the uplink component carrier is in an active state at the time for transmitting the SRS, and the uplink component carrier is configured to allow an uplink signal transmission in the active state, wherein the SRS transmission is skipped on the uplink component carrier at a time for transmitting the SRS when the uplink component carrier is in a non-active state at the time for transmitting the SRS, and the uplink component carrier is configured not to allow an uplink signal transmission in the non-active state, wherein a first downlink component carrier is paired with the first uplink component carrier, and the first downlink and uplink component carriers are always in the active state, and wherein the active/non-active states of the second uplink component carrier are controlled by using Layer 2 (L2) control signaling, and the second uplink component carrier and a second downlink component carrier paired with the second uplink component carrier have a same state among the active/non-active states.

5. The user equipment of claim 4 , wherein the second uplink component carrier is in the non-active state, when multiple downlink component carriers paired with the second uplink component carrier are all in a non-active state.

6. The user equipment of claim 4 , wherein information for the second downlink component carrier and the second uplink component carrier is configured by using RRC signaling, and active/non-active states of the second downlink component carrier are controlled by using the L2 control signaling based on the information configured by the RRC signaling.