5G NR SIB scheduling

Hello everyone!

I was wondering if anyone here can help me with any information regarding the scheduling of Other SIBs, specifically other that SIB1. I got sib 1 to work and received it at UE, but I am unable to send and decode other SIBs (e.g. SIB2)

Hi,

For 5G NR, SIB1 will carry all the essential system information. Along with this it can carry details about other SIBs which can be either:

  1. Periodically broadcasted or

  2. SIB 1 will contain details related to On demand via system information request. If this is the case Other system information (OSI) can be requested Via RACH and network will respond with OSI/SIB2-SIB9 as a response.

Elaborating more on OSI request - SIB1 will contain SI-SchedulingInfo IE , which will guide UE on to select unique PRACH Preambles and resources assigned for OSI request.
a) UE will trigger CBRA RACH procedure, MSG1 and MSG2 are same as regular RACH.
b) In MSG3 UE will send SI-Request which is included in RRC System Info Request Message. There is an IE requested-SIList which allows UE to request all SIBs or specific SIBs.
c) As a response of MSG3 , network will send other requested system information.

You can refer to 3GPP TS 38.331 5.2.2.3.3. For a simpler understanding you can also refer to 5G NR in Bullet Section 06 (Pg.265) and find more details.

Hope this helps you with your query. Happy to discuss further and learn from further interactions.

Quick reference from 5G NR bullet book.

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