My Radio Technology beyond LTE - 38 series notes

38.300

Section 7 Radio Resource Controller (RRC)

7.1 Services and Functions

The main services and functions of the RRC sublayer over the Uu interface include:

• Broadcast of System Information related to AS and NAS;
• Paging initiated by 5GC or NG-RAN;
• Establishment, maintenance and release of an RRC connection between the UE and NG-RAN including:
  • Addition, modification and release of carrier aggregation;
  • Addition, modification and release of Dual Connectivity in NR or between E-UTRA and NR.
• Security functions including key management;
• Establishment, configuration, maintenance and release of Signalling Radio Bearers (SRBs) and Data Radio Bearers (DRBs);
• Mobility functions including:
  • Handover and context transfer;
  • UE cell selection and reselection and control of cell selection and reselection;
  • Inter-RAT mobility.
• QoS management functions;
• UE measurement reporting and control of the reporting;
• Detection of and recovery from radio link failure;
• NAS message transfer to/from NAS from/to UE.

The sidelink specific services and functions of the RRC sublayer over the Uu interface include:

• Configuration of sidelink resource allocation via system information or dedicated signalling;
• Reporting of UE sidelink information;
• Measurement configuration and reporting related to sidelink;
• Reporting of UE assistance information for SL traffic pattern(s).

7.2 Protocol States RRC supports the following states which can be characterised as follows:

• RRC_IDLE:
  • PLMN selection;
  • Broadcast of system information;
  • Cell re-selection mobility;
  • Paging for mobile terminated data is initiated by 5GC;
  • DRX for CN paging configured by NAS.
• RRC_INACTIVE:
  • PLMN selection;
  • Broadcast of system information;
  • Cell re-selection mobility;
  • Paging is initiated by NG-RAN (RAN paging);
  • RAN-based notification area (RNA) is managed by NG- RAN;
  • DRX for RAN paging configured by NG-RAN;
  • 5GC - NG-RAN connection (both C/U-planes) is established for UE;
  • The UE Inactive AS context is stored in NG-RAN and the UE;
  • NG-RAN knows the RNA which the UE belongs to;
  • Transfer of unicast data and/or signalling to/from the UE over radio bearers configured for SDT.
• RRC_CONNECTED:
  • 5GC - NG-RAN connection (both C/U-planes) is established for UE;
  • The UE AS context is stored in NG-RAN and the UE;
  • NG-RAN knows the cell which the UE belongs to;
  • Transfer of unicast data to/from the UE;
  • Network controlled mobility including measurements.

To My New Radio (NR) notes