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, 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; characterized in that the method further includes: 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 if the uplink component carrier is in an available state at a time for transmitting the SRS, an SRS transmission is performed on the uplink component carrier at the time for transmitting the SRS, wherein if the uplink component carrier is in a non-available state at the time for transmitting the SRS, the SRS transmission is skipped on the uplink component carrier at the time for transmitting the SRS, wherein the available/non-available states of the uplink component carrier are controlled by using Layer 1 or 2, L1/L2, control signaling, and wherein a normal signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the available state, and a limited signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the non-available state. 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; characterized in that the method further includes: 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 if the uplink component carrier is in an available state at a time for transmitting the SRS, an SRS transmission is performed on the uplink component carrier at the time for transmitting the SRS, wherein if the uplink component carrier is in a non-available state at the time for transmitting the SRS, the SRS transmission is skipped on the uplink component carrier at the time for transmitting the SRS, wherein the available/non-available states of the uplink component carrier are controlled by using Layer 1 or 2, L1/L2, control signaling, and wherein a normal signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the available state, and a limited signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the non-available state. 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 if the uplink component carrier is in an available state at a time for transmitting the SRS, an SRS transmission is performed on the uplink component carrier at the time for transmitting the SRS, wherein if the uplink component carrier is in a non-available state at the time for transmitting the SRS, the SRS transmission is skipped on the uplink component carrier at the time for transmitting the SRS, wherein the available/non-available states of the uplink component carrier are controlled by using Layer 1 or 2, L1/L2, control signaling, and wherein a normal signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the available state, and a limited signal reception is performed by the user equipment on a downlink component carrier paired with an uplink component carrier in the non-available state.