Hello Experts.
When using NARCN method SSB, why need to calculate offset although already SSB ARFCN number configured in cell configuration?
I mean, why UE points directly to SSB ARFCN?
1 Like
SSB ARFCN defines Central frequency of SSB.
Since it is a huge Bandwidth UE Can’t do blind search for all ARFCN.
Offset is required to define CORESETZERO Position and abs frequency point A to define CRB0.
1 Like
Thanks.
But why UE points directly to SSB Position (NARFCN) that have been sent in RRC-Reconfigure in NSA?
1 Like
SSB Position required for NSA UE to send SSB Based measurements & SRS Signal transmission.
1 Like
Thanks, but still trying to figure, why does UE NSA decode directly the SSB-ARFCN send in RRC-reconfig without need for offset_A calculation?
1 Like
Because the UE gets the SSB information directly from 4G site.
1 Like
SSB centre Freq is informed to the UE by MeNB so that UE can locate the SS Block and synchronise with the PSS and SSS and calculate the PCI and read the SS-RSRP.
1 Like
Thanks again, but I mean why need offset_A calculation to get SSB location however AbsoluteFrequencySSB is already sent?
To know the start point of the bandwidth.
1 Like
Why needed?
Why not go directly to AbsoluteFrequencySSB that express where SSB located?
I think that is only for SA, NSA UE can know that info from RRC reconfig.
NSA UE does not required Offset calculation because System information already shared to the UE Via NR RRC Reconfiguration.
SSB location determined interns of ARFCN because UE calculates the AbsoluteFrequency SSB By using global raster which will be vary based on Frequency range.
ARFCN Will be used for key derivation as well.
You can check this:
5G NR SSB Positioning – Time and Frequency Resources 5G NR SSB Positioning - Time and Frequency Resources - Techplayon
Hello, please check this conversation: Does GSCN reflect offsettopointa and KSSB? - #16 by Mohamedeladawi