In accordance with another aspect of the present disclosure, a user equipment is provided for controlling states of a secondary cell. The user equipment includes a receiver configured to receive secondary cell (SCell) state indication information indicating a state for the SCell from a base station through a RRC message or a MAC control element, a controller configured to cause a state of the SCell to transition into a dormant state when the SCell state indication information indicates the dormant state, and a transmitter configured to transmit channel state information reporting for the SCell in the dormant state according to an dormant state CQI report period parameter set separately from an activation state CQI report period parameter.

In accordance with another aspect of the present disclosure, a base station is provided for controlling states of a secondary cell of a user equipment. The base station includes a transmitter configured to transmit secondary cell (SCell) state indication information indicating a state for the SCell to the user equipment through an RRC message or a MAC control element, and when the SCell enters a dormant state according to the SCell state indication information, a receiver configured to receive channel state information reporting for the SCell in the dormant state according to an dormant state CQI report period parameter set separately from an activation state CQI report period parameter.

In accordance with the present disclosure, it is possible to perform operations rapidly even when a state is transitioned into an activation state by defining a dormant state of a secondary cell configuring carrier aggregation.

In accordance with the present disclosure, it is also possible to eliminate the ambiguity of operations by defining methods and signals for changing a Scell′ states including a dormant state.