7.1 Services and Functions

36.3003GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN)Overall descriptionRelease 17Stage 2TS

The main services and functions of the RRC sublayer include:

– Broadcast of System Information related to the non-access stratum (NAS);

– Broadcast of System Information related to the access stratum (AS);

– Paging;

– Establishment, maintenance and release of an RRC connection between the UE and E-UTRAN including:

– Allocation of temporary identifiers between UE and E-UTRAN;

– Configuration of signalling radio bearer(s) for RRC connection:

– Low priority SRB and high priority SRB;

– For NB-IoT, a UE dedicated SRB is supported before AS security is activated and only one UE dedicated SRB is supported after AS security is activated;

– For a NB-IoT UE that supports S1-U data transfer or User Plane CIoT EPS optimisation, as defined in TS 24.301 [20]; or

– For a NB-IoT UE that supports NG-U data transfer or User Plane CIoT 5GS Optimisation, as defined in TS 24.501 [91]:

– One DRB is supported by default and up to two DRBs are supported optionally;

– For a UE that supports User Plane CIoT EPS optimisation, as specified in TS 24.301 [20]; or

– For a UE that supports User Plane CIoT 5GS Optimisation, as specified in TS 24.501 [91]:

– Suspension/resuming of the RRC connection;

– Security functions including key management;

– Establishment, configuration, maintenance and release of point to point Radio Bearers;

– Mobility functions including:

– UE measurement reporting and control of the reporting for inter-cell and inter-RAT mobility;

– Handover;

– UE cell selection and reselection and control of cell selection and reselection;

– Context transfer at handover.

– Notification and counting for MBMS services;

– Establishment, configuration, maintenance and release of Radio Bearers for MBMS services;

– QoS management functions;

– UE measurement reporting and control of the reporting;

– NAS direct message transfer to/from NAS from/to UE.