There are another key factors in LTE which similar items are known from legacy networks. System Information Blocks and Master Information Block. These information messages are sent by the network to UE to keep it updated about cell selection, cell reselection, power control, DRX parameters and etc. And it is carried only for downlink, from eNodeB to UE.
In LTE there are several versions of System Information Blocks (SIB) and Master Information Block (MIB), each of them carries different information to UE.
MIB message: is broadcasted on PBCH. There is only one type of MIB.
SIB messages: are sent on PDSCH through RRC layer:
• SIB1 is carried under “SystemInformationBlockType 1” message name.
• Other SIBs are carried under “SystemInformation” message name and can contain multiple SIBs in the one message.
Time scheduling and periodicity are fixed for MIB and SIB1, so it means that locations are fixed for both messages in system frame. Time scheduling and periodicity are configurable for the rest of SIB messages.
MIB: is always sent in sub-frame #0 of the Radio-Frame, and continues retransmitting the same message in each 10 ms with different redundancy versions. Each 40ms a new MIB is transmitted.
SIB1: is always sent in sub-frame #5 of the Radio-Frame, and continues retransmitting the same message in each 20 ms with different redundancy versions. Each 80ms a new SIB1 is transmitted.
Time scheduling and periodicity for the rest of SIB messages are determined by “schedulingInfoList” in SIB1.
Credit to: Ziya
