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WCDMA SIB (System Information Block) Types Explained

wcdma sib umts system information network

This section covers the different types of System Information Blocks (SIBs) used in WCDMA (UMTS) networks.

Introduction to WCDMA SIBs

SIB messages in UMTS provide essential information to User Equipments (UEs) about the network. These messages include:

  • MIB (Master Information Block)
  • Scheduling Block 1
  • Scheduling Block 2
  • SIB1, SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, SIB9, SIB10, SIB11, SIB12, SIB13, SIB13.4, SIB14, SIB15, SIB15.4, SIB16, SIB17, and SIB18.

The MIB (Master Information Block) is crucial as it carries scheduling information for the other SIBs, as well as for Scheduling Block 1 and Scheduling Block 2. Scheduling Block 1 and Scheduling Block 2 are optional blocks also used for SIBs.

WCDMA SIB Types and their Functions

The following table summarizes the different WCDMA SIB types and the information they carry:

System Information Block in UMTS typeFunction (Information carried)
SIB1NAS (Non-Access Stratum) information, timer-related information mainly used in IDLE/CONNECTED Mode
SIB2Available URAs (UTRAN Registration Areas) (max. 8 URAs in a cell)
SIB3Cell selection/reselection parameters used by UE in IDLE mode; if SIB4 is not present, it can also be used by UEs in CONNECTED MODE.
SIB4Cell selection/reselection parameters used by UE in CONNECTED mode; if not present, SIB3 is used by the UE.
SIB5Carries information on common physical channels (PICH/AICH/P-CCPCH/PRACH/SCCPCH) for UE in IDLE mode; in the absence of SIB6, it is also used for UE in CONNECTED state.
SIB6Carries information on common physical channels (PICH/AICH/P-CCPCH/PRACH/SCCPCH) for UE in CONNECTED mode; in the absence of SIB6, UE needs to use SIB5.
SIB7Carries fast-changing cell parameter information (uplink interference levels, dynamic persistence value).
SIB8Carries static information for CPCH (Common Packet Channel) (only for FDD use).
SIB9Carries dynamic information for CPCH (only for FDD use).
SIB10DRAC (Dynamic Radio Access Control) procedure-related information (sent over FACH channel).
SIB11Carries measurement control information (UE in IDLE mode); if SIB12 is absent, it is also used for UE in CONNECTED mode.
SIB12Carries measurement control information (UE in CONNECTED mode); if SIB12 is absent, SIB11 can be used by the UE.
SIB13-SIB13.4Carries ANSI-41 parameter-related information used for ANSI-41 core networks.
SIB14Carries outer loop power control information (TDD mode use only), used over dedicated and common physical channels.
SIB15-SIB15.4Carries information used for UE positioning methods (e.g., GPS/OTDOA).
SIB16Carries information related to channel configuration used for handover.
SIB17Carries information on shared common channels (to be used in CONNECTED mode, TDD use).
SIB18Carries PLMN (Public Land Mobile Network) identities of neighboring cells (used by UE in IDLE/CONNECTED MODE).