UEs in RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED state about an SI change. If the UE receives a short message with SI change indication, it means that the SI will change at the next modification period boundary [8]. As we mentioned earlier, the SI is divided into the MIB and a number of SIBs. The MIB is always transmitted on the BCH with a periodicity of 80 ms and is repeated within the 80 ms. The MIB includes parameters that are needed to acquire SIB1 from the cell. The SIB1 is transmitted on the DL-SCH with a periodicity of 160 ms and variable transmis- sion repetition periodicity within 160 ms. The default repetition period of SIB1 is 20 ms; however, the actual repetition periodicity is up to network implementation. For synchroniza- tion signal/PBCH block (SSB) and CORESET multiplexing pattern 1, SIB1 repetition trans- mission period is 20 ms. For SSB and CORESET multiplexing pattern 2/3, SIB1 repetition period is the same as the SSB period. The SIB1 includes information regarding the avail- ability and scheduling (e.g., mapping of SIBs to SI message, periodicity, and SI-window size) of other SIBs with an indication whether the SIBs are only provided on-demand, and in that case the configuration needed by the UE to perform the SI request. The SIB1 is cell- specific. Other SIBs are carried in SI messages, which are transmitted on the DL-SCH. The SIBs with the same periodicity can only be mapped to the same SI message. Each SI message is transmitted within periodically occurring time domain windows referred to as SI-windows with same length for all SI messages. Each SI message is associated with an SI-window and New Radio Access Layer 2/3 Aspects and System Operation 241 the SI-windows of different SI messages do not overlap. That is, within one SI-window only the corresponding SI message is transmitted. Any SIB except SIB1 can be configured to be cell-specific or area-specific, using an indication in SIB1. The cell-specific SIB is applicable only within the cell that provides the SIB, while the area-specific SIB