LTE - S1AP UE attach

Diagram*

About MIB ->
The Master Information Block (MIB) in LTE (Long-Term Evolution) serves as a fundamental element in the broadcast of essential information about the cell. Specifically, the MIB carries physical layer (PHY) information about the LTE cell. The PHY information in the MIB is crucial for several reasons:

Cell Identification:
    The MIB includes information such as the PLMN (Public Land Mobile Network) identity and the Cell Identity (CID). This enables user equipment (UE) to identify and locate the specific LTE cell it is connected to.

Frame Configuration:
    The MIB provides details about the radio frame structure, including the length of radio frames, subframes, and the configuration of the subframes. This information is essential for UEs to synchronize with the cell's timing and decode subsequent system information.

System Bandwidth:
    The MIB contains information about the system bandwidth, which is necessary for UEs to configure their receivers to the appropriate bandwidth for communication with the cell.

PHICH Configuration:
    The Physical Hybrid-ARQ Indicator Channel (PHICH) configuration details are included in the MIB. PHICH is used for the uplink acknowledgment signaling, and its configuration is crucial for decoding ACK/NACK (acknowledgment/negative acknowledgment) information.

System Frame Number (SFN):
    The MIB includes the System Frame Number (SFN), which is used for time synchronization between the UE and the cell. The SFN helps in coordinating communication and scheduling between the UE and the network.

Cell Specific Reference Signals:
    Information about the Cell Specific Reference Signals (CRS) is broadcasted in the MIB. CRS is used by UEs for channel estimation, enabling them to determine the channel conditions and optimize their transmissions.