When UE is in RRC_IDLE mode, it needs to read the system information for cell selection and cell reselection.
System Information(SI) will be transmitted periodically by base station.
In 5G NR the SI is divided into 3 parts as below:
1. Minimum System Information (MSI)
2. Remaining Minimum System Information (RMSI)
3. Other System Information (OSI)
MSI includes MIB and SIB1
RMSI includes SIB1
OSI includes Other System Information fro SIB2 through SIB9.
Mapping of system information and channels:
MIB -> BCCH -> BCH -> PBCH
SIB1 to 9 -> BCCH -> DL-SCH -> PDSCH
Below is the list of SI in brief. In next chapters we shall have an indepth understanding of MIB/SIB.
0. Master Information Block (MIB) : SFN, SCS, SIB1 PDCCH resource, cell barred information, Intra frequency reselection allowed flag
1. System Information Block 1 (SIB1): Cell selection Information, PLMN, TAC, Cell ID, TAC, RAN area code, RAN Notification Information, SI scheduling info for OSI, Serving Cell Information, UE’s timers and constants
2. System Information Block 2 (SIB2): Cell re-selection information for intra-frequency, inter-frequency and/ or inter-RAT
3. System Information Block 3 (SIB3): Intra frequency cell re-selection information e.g. PCI, q-Offset, q-RxLev, q-Qual, Black cell list
4. System Information Block 4 (SIB4): Inter frequency cell re-selection information e.g. NR-ARFCN
5. System Information Block 5 (SIB5): Inter system cell re-selection toward LTE e.g. EARFCN
6. System Information Block 6 (SIB6): Earth quake and Tsunami Warning System primary notifications
7. System Information Block 7 (SIB7): Earth quake and Tsunami Warning System secondary notifications
8. System Information Block 8 (SIB8): Commercial Mobile Alert services (CMAS) notification
9. System Information Block 9 (SIB9): Information related to UTC, GPS and local time
On Demand SIB:
OSI: Other Sysem Information includes from SIB2 to SIB9. They are also called as On-Demand SI. Because gNB broadcast these SIB when UE requests.
We shall learn about On Demand SIB in next chapter.
TS 38.331, TS 38.321