up (MCG)). The MIB is always transmitted on the BCH with a periodicity of 80 ms and repeti- tions within 80 ms, and it includes parameters that are needed to acquire SIB1 from the cell. The first transmission of the MIB is scheduled in subframes as defined in [2], and repetitions are scheduled according to the period of the SSB. SIB1 is transmitted on the DL-SCH with a periodicity of 160 ms and variable trans- mission repetition periodicity as specified in TS 38.213 [13, Section 13]. The default transmission repetition periodicity of SIB1 is 20 ms, but the actual transmission rep- etition periodicity is up to the network implementation. For the SSB and CORESET multiplexing pattern 1, the SIB1 repetition transmission period is 20 ms. For the SSB and CORESET multiplexing pattern 2/3, the SIB1 transmission repetition period is the same as the SSB period. SIBs other than SIB1 are carried in SystemInformation (SI) messages, which are trans- mitted on the DL-SCH. Only SIBs having the same periodicity can be mapped to the same SI message. Each SI message is transmitted within periodically occurring time domain windows (referred to as SI-windows having the same length for all SI mes- sages). Each SI message is associated with an SI-window, and the SI-windows of different SI messages do not overlap. That is, within one SI-window, only the corresponding SI message is transmitted. Figure 7.18 shows how the UE can find each SI message to read the actual SIBs in it. SIB1 includes information regarding the availability and scheduling (e.g. mapping of SIBs to the SI message, periodicity, and SI-window size) of other SIBs with an indication cellAccessRelatedInformation; cellSelectionInfo; frequecyBandIndicator; schedulingInformation; SI 1: { 8, SIB3, SIB4} SI 2: 16, SIB5} SI 3: {32, SIB6, SIB7, SIB8} si-Window=5ms; systemInformationVal si-Periodicity 150 160 determine integer value X= (n 1)*w, where n is the order of entry in the list of SI message and W is the si-WindowLength si-Window starts at subframe #a, where a = X mod 10,