How does UE knows which Subcarrier Spacing is broadcasted by gNB?

5G NR
1

Hello Experts.
How does UE knows which Subcarrier Spacing is broadcasted by gNB?

2

You can check spcellconfigcommon. There you will find subcarrier spacing.

3

From MIB, SIB1.

4

subCarrierSpacingCommon: Indicates the Subcarrier spacing for SIB1, Message 2/4 for initial access and System information-messages. It can have values 15 and 30 kHz valid for carrier frequencies < 6 GHz; values 60 and 120 kHz are applicable for carrier frequencies > 6 GHz.

Above it says SCS for SIB1.
So does that mean for every Control Msg and Data Msg, this SCS value will change?
Or will it be fix for entire data duration?

5

SCS for SIB1 is derived from MIB.
SCS for the initial BWP is given in BWP configuration in SIB1.
Once UE is attached, UE can be configured with multiple BWPs where each BWP is characterized by its own SCS.
Based on the bwp that UE is currently on, UE will know the subcarrier spacing.

6

SCS is cell parameter and not BWP.
It is independent of in which BWP UE is.

7

Hi dear @Laxman, I think you misunderstood.
I never mentioned that SCS is specific to UE.
BWP configuration is specific to UE.
Each BWP is characterized by its own SCS.
UE realises the SCS based in BWP config (UL/DL).
Network needs to configure the bwp keeping the SCS deployments within the cell bandwidth in mind.

8

Do you know whether any RAN vendor implemented this?

9

No idea. But, this is how it works as per 3gpp.