What is RRC in 5G?

RRC stands for Radio Resource Control . I personally define RRC as a common language that should be understood by both Network and UE. As you know, UE and Network is communicating via radio channel.

In case of suspending the RRC connection the RRC Release message contains a set of suspend configuration parameters. The probably most important one is the I-RNTI , the (RRC) Inactive Radio Network Temporary Identity. … Just NGAP RRC Inactivity Transition Report is sent to the AMF.

In summary, a UE is in RRC_CONNECTED when an RRC connection has been established or in RRC_INACTIVE (if the UE is connected to 5GC) when RRC connection is suspended . If this is not the case, i.e. no RRC connection is established, the UE is in RRC_IDLE state.

The UE is notified about the 5G bearer via the RRC Connection Reconfiguration message. The UE then connects to the 5G network while maintaining the connectivity to the 4G network .

When UE is power up it is in Disconnected mode/Idle mode, It can move RRC connected with initial attach or with connection establishment. If there is no activity from UE for a short time, It can suspend its session by moving to RRC Inactive and can resume its session moving to RRC connected mode .19 Kas 2017

Radio Resource Control ( RRC ) is a layer within the 5G NR protocol stack . It exists only in the control plane, in the UE and in the gNB . The behaviour and functions of RRC are governed by the current state of RRC . In 5G NR , RRC has three distinct states: RRC_IDLE, RRC_CONNECTED and RRC_INACTIVE.6 Mar 2021

Differences between LTE RRC states and UMTS RRC States In LTE there is only 2 RRC states i.e. RRC_IDLE and RRC_CONNECTED whereas in UMTS system RRC has a 5 state i.e. IDLE, CELL_FACH, CELL_DCH, CELL_PCH and URA_PCH.