Sign in Subscribe

SIB (System Information Block)

Last updated on 


System Information Blocks (SIBs) are an essential component of cellular networks, specifically in the context of Long-Term Evolution (LTE) and 5G networks. SIBs contain important system-related information that is broadcasted by the base station (eNodeB in LTE or gNodeB in 5G) to the mobile devices (UEs) within its coverage area. These blocks of information assist UEs in various network-related procedures, including initial cell selection, cell reselection, handover, and network access.

SIBs are transmitted over specific control channels, known as Broadcast Channels (BCH), which operate on a continuous basis. The BCH carries essential information that UEs need to establish a connection with the network. SIBs are periodically transmitted to ensure that UEs can update their system parameters and make informed decisions regarding network access and mobility.

Here are the main types of SIBs used in LTE and 5G networks:

  1. SIB1: This is the most critical SIB and provides essential information about the network, including the PLMN (Public Land Mobile Network) identity, cell identity, tracking area information, and system bandwidth. SIB1 helps UEs determine the network's availability and compatibility.
  2. SIB2: SIB2 contains detailed information about the cell and network configuration. It provides crucial parameters such as frequency bands, neighbor cell lists, radio resource allocation, and mobility-related parameters. SIB2 assists UEs in making decisions related to cell reselection and handover.
  3. SIB3: SIB3 carries information related to cell reselection and handover parameters. It includes parameters like cell reselection thresholds, measurement configurations, and neighboring cells' measurement information.
  4. SIB4: SIB4 provides information regarding the Master Information Block (MIB) modification period and the subframe allocation used for the BCH. It helps UEs synchronize their timing with the network.
  5. SIB5: SIB5 contains information related to the paging cycle and paging parameters used for UE paging. UEs monitor the paging channel to detect incoming calls or messages.
  6. SIB6: SIB6 carries information about the default paging cycle and its related parameters. It is applicable to UEs that are in idle mode.
  7. SIB7: SIB7 provides parameters for non-access stratum (NAS) signaling connection release.
  8. SIB8: SIB8 contains information regarding the positioning methods supported by the network, such as Global Navigation Satellite System (GNSS) assistance data.
  9. SIB9: SIB9 is used in 5G networks and provides information about the system's capability, frequency bands, and radio resource configuration.

These SIBs are periodically transmitted by the base station, allowing UEs to decode and extract the relevant information. The SIBs provide essential details for UEs to establish and maintain a connection with the cellular network, enabling efficient network access, mobility, and handover procedures.