7.4 System Information

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

System information is divided into the MasterInformationBlock (MIB) and a number of SystemInformationBlocks (SIBs):

– MasterInformationBlock defines the most essential physical layer information of the cell required to receive further system information;

– SystemInformationBlockPos contains positioning assistance data;

– SystemInformationBlockType1 and SystemInformationBlockType1-BR (for a BL UE or UE in enhanced coverage) contain information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other system information blocks;

– SystemInformationBlockType2 contains common and shared channel information;

– SystemInformationBlockType3 contains cell re-selection information, mainly related to the serving cell;

– SystemInformationBlockType4 contains information about the serving frequency and intra-frequency neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters);

– SystemInformationBlockType5 contains information about other E‑UTRA frequencies and inter-frequency neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters). It can also contain information about E-UTRA and NR idle/inactive measurements;

– SystemInformationBlockType6 contains information about UTRA frequencies and UTRA neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters);

– SystemInformationBlockType7 contains information about GERAN frequencies relevant for cell re-selection (including cell re-selection parameters for each frequency);

– SystemInformationBlockType8 contains information about CDMA2000 frequencies and CDMA2000 neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters);

– SystemInformationBlockType9 contains a home eNB name (HNB name);

– SystemInformationBlockType10 contains an ETWS primary notification;

– SystemInformationBlockType11 contains an ETWS secondary notification;

– SystemInformationBlockType12 contains a CMAS warning notification;

– SystemInformationBlockType13 contains MBMS-related information;

– SystemInformationBlockType14 contains information about Extended Access Barring for access control;

– SystemInformationBlockType15 contains information related to mobility procedures for MBMS reception;

– SystemInformationBlockType16 contains information related to GPS time and Coordinated Universal Time (UTC);

– SystemInformationBlockType17 contains information relevant for traffic steering between E-UTRAN and WLAN;

– SystemInformationBlockType18 contains information related to sidelink communication;

– SystemInformationBlockType19 contains information related to sidelink discovery;

– SystemInformationBlockType20 contains information related to SC-PTM;

– SystemInformationBlockType21 contains information related to V2X sidelink communication;

– SystemInformationBlockType24 contains information about NR frequencies and NR neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency), which can also be used for NR idle/inactive measurements;

– SystemInformationBlockType25 contains information about UAC parameters;

– SystemInformationBlockType26 contains additional information related to V2X sidelink communication;

– SystemInformationBlockType26a contains information related to NR bands list which can be used for EN-DC operation with the serving cell;

– SystemInformationBlockType27 contains assistance information for inter-RAT cell selection to NB-IoT;

– SystemInformationBlockType28 contains information related to NR sidelink communication;

– SystemInformationBlockType29 contains information related to common resource reservation;

– SystemInformationBlockType30 contains information related to disaster roaming;

– SystemInformationBlockType31 contains information required for accessing an NTN cell;

– SystemInformationBlockType32 contains assistance information for discontinuous coverage in NTN.

System information for NB-IoT is divided into the MasterInformationBlock-NB (MIB-NB) and a number of SystemInformationBlocks-NB (SIBs-NB):

– MasterInformationBlock-NB defines the most essential information of the cell required to receive further system information;

– SystemInformationBlockType1-NB contains information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other system information blocks;

– SystemInformationBlockType2-NB contains common radio resource configuration information;

– SystemInformationBlockType3-NB contains cell re-selection information for intra-frequency, inter-frequency;

– SystemInformationBlockType4-NB contains neighboring cell related information relevant for intra-frequency cell re-selection;

– SystemInformationBlockType5-NB contains neighboring cell related information relevant for inter-frequency cell re-selection;

– SystemInformationBlockType14-NB contains information about access barring;

– SystemInformationBlockType15-NB contains information related to mobility procedures for MBMS reception;

– SystemInformationBlockType16-NB contains information related to GPS time and Coordinated Universal Time (UTC);

– SystemInformationBlockType20-NB contains information related to SC-PTM;

– SystemInformationBlockType22-NB contains common radio resource configuration information for paging and random access procedure on non-anchor carriers;

– SystemInformationBlockType23-NB contains common additional radio resource configuration information for random access procedure on anchor and non-anchor carriers;

– SystemInformationBlockType27-NB contains assistance information for inter-RAT cell selection to E-UTRAN and/or GERAN;

– SystemInformationBlockType31-NB contains information required for accessing an NTN cell;

– SystemInformationBlockType32-NB contains assistance information for discontinuous coverage in NTN.

On MBMS-dedicated cell, only system information relevant for receiving MBMS service is broadcasted. MasterInformationBlock-MBMS (MIB-MBMS) and SystemInformationBlockType1-MBMS (SIB1-MBMS) are used instead of MIB and SIB1 respectively:

– MasterInformationBlock-MBMS defines the most essential physical layer information of the cell required to receive further system information on MBMS-dedicated cell;

– SystemInformationBlockType1-MBMS contains information relevant for receiving MBMS service and defines the scheduling of other system information blocks on MBMS-dedicated cell;

The MIB is mapped on the BCCH and carried on BCH while all other SI messages are mapped on the BCCH and BR-BCCH, and carried on DL-SCH. Except for BL UEs, UEs in enhanced coverage and NB-IoT UEs, all other SI messages than the MIB which are dynamically carried on DL-SCH, can be identified through the SI-RNTI (System Information RNTI). Both the MIB and SystemInformationBlockType1 (SystemInformationBlockType1-BR for BL UEs and UEs in enhanced coverage) use a fixed schedule with a periodicity of 40 and 80 ms respectively. The scheduling of other SI messages is flexible and indicated by SystemInformationBlockType1 (SystemInformationBlockType1-BR for BL UEs and UEs in enhanced coverage, and SystemInformationBlockType1-NB for NB-IoT). For NB-IoT, the MIB-NB is mapped on the BCCH and carried on BCH while all other SI messages are mapped on the BCCH and carried on DL-SCH. Both the MIB-NB and SystemInformationBlockType1-NB use a fixed schedule with a periodicity of 640 and 2560 ms respectively. The MIB-NB contains all information required to acquire SIB1-NB and SIB1-NB contains all information required to acquire other SI messages.

On MBMS-dedicated cell, the MIB-MBMS and SIB1-MBMS use a fixed schedule with a periodicity of 160 ms. Additionally, SIB1-MBMS may be scheduled in additional non-MBSFN subframes indicated in MIB-MBMS.

For NB-IoT, in TDD mode, the MIB-TDD-NB is transmitted on the same NB-IoT carrier as NPSS/NSSS, SystemInformationBlockType1-NB can be transmitted on NB-IoT carrier other than the MIB-NB, and the SI messages can be transmitted on a NB-IoT carrier other than the MIB-NB. At most two NB-IoT carriers are used to transmit the MIB-NB, SystemInformationBlockType1-NB and the SI messages.

Except for NB-IoT, the eNB may schedule DL-SCH transmissions concerning logical channels other than BCCH or BR-BCCH in the same subframe as used for BCCH or BR-BCCH. The minimum UE capability restricts the BCCH or BR-BCCH mapped to DL-SCH e.g. regarding the maximum rate.

The Paging message is used to inform UEs in RRC_IDLE and UEs in RRC_CONNECTED about a system information change. For NB-IoT UEs, BL UEs, and UEs in CE, the UE is not required to detect SIB changes when in RRC_CONNECTED, and the network may release the NB-IoT UE, BL UE or UE in CE to RRC_IDLE if it wants the NB-IoT UE, BL UE or UE in CE to acquire changed SIB(s).

Except for NB-IoT, system information may also be provided to the UE by means of dedicated signalling e.g. upon handover.