In the present disclosure, an activation state denotes a state capable of transmitting/receiving data by performing operations of a normal SCell. A deactivation state denotes a state in which a SCell is configured on a UE, but a transmission or reception operation, or the like is not performed for the SCell. A dormant state is a state newly defined in accordance with at least one embodiment. The dormant state denotes a state in which at least one operation in the activation state and at least one operation in the deactivation state are mixed. The dormant state may be replaced by an arbitrary term, such as a fast activation state, mid activation state, low power activation state, high power deactivation state, new SCell state, mid power SCell state, mid state, mid activated state, semi activated state, semi deactivated state, or the like. Terms on states described above are just examples, and not limited thereto.

In the present disclosure, channel state information reporting includes information on channels measured, estimated or calculated by a UE and is described as CSI reporting, CQI reporting, or the like. This is for convenience of description. The channel state information reporting denotes reporting including at least one of CQI, PMI, RI, PTI and CRI. In addition, hereafter, if necessary, the channel state information reporting may be discussed using CSI reporting or CQI reporting, and should be construed as meaning including all of the channel state information described above except for a particular situation.

Carrier aggregation (CA) technology is a technique for boosting a data transmission rate for a UE through an additional carrier. Typical CA technology has not been optimized for the configuration of a SCell and an activation state for the SCell from latency perspective.