Clarification on Subcarrier Spacing for Downlink and Uplink Channels in NR

[ankgitm]

Hello NR experts,

The options for subcarrier spacing can be seen in the following locations:

1. Downlink Config Common under the SCS-SpecificCarrier IE
2. Initial Downlink BWP under the SubCarrierSpacing IE
3. Uplink Config Common under the SCS-SpecificCarrier IE
4. Initial Uplink BWP under the SubCarrierSpacing IE
5. RACH-ConfigGeneric, which has MSG1-SubCarrierSpacing
6. TDD UL-DL configuration with a reference to SubCarrierSpacing

All this information is part of SIB1 for NR SA.

Can we say:

• The DL option under Initial Downlink BWP indicates the SCS for PDSCH and PDCCH channels?
• The UL option under Uplink BWP indicates the SCS for PUCCH, PRACH, and PUSCH channels?

Admin note: this post was updated with image below.

[Manoj_deka]

1. The SCS within the initialDLBWP indicates the PDSCH SCS.
2. . The SCS within the initialULBWP indicates the PUSCH SCS.
3. SubcarrierspacingCommon within MIB indicates PDCCH SCS.
4. For PRACH, the SCS depends on the Preamble Format which is already fixed by 3GPP, no need to explicitly mentioned

[pappu_kumar_Chaurash]

scs within initial BWP or other bwp is used for all the channel and reference signal unless explicitly configured somewhere.

scsCommon in MIB is used SIB1, Msg2/Msg4 and other SIBs. Here we used to see two value and UE pick the value as per carrier frequency like for <6GHz use first value and for >6GHz select second one.

For PRACH yes its depends on preamble format.

Above statements are as per 38.331