In the present disclosure, a narrowband Internet of Things (NB-IoT) device refers to a device supporting radio access for cellular IoT. NB-IoT technology aims at improved indoor coverage, support for large-scale low-speed devices, low latency sensitivity, very low device costs, low power consumption, and optimized network architecture.
An enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable and low latency communication (URLLC) are proposed as representative usage scenarios for NR.
A frequency, a frame, a subframe, a resource, a resource block (RB), a region, a band, a sub-band, a control channel, a data channel, a synchronization signal, various reference signals, various signals, and various messages associated with NR of the present disclosure may be interpreted as being used in the past or present or as various meanings to be used in the future.
Hereinafter, a method and an apparatus for controlling carrier aggregation and a state of a secondary cell in accordance with embodiments of the present disclosure will be described in detail.
In the present disclosure, a secondary cell denotes a cell providing an additional radio resource other than a primary cell (PCell) serving as a reference for RRC connection when a UE configures carrier aggregation. The secondary cell may be described as SCell, but the term is not limited thereto. In addition, in the present disclosure, description or embodiments related to state changes of the SCell apply to a normal cell providing an additional radio resource, and may not apply to the PSCell, or a special cell.