Requirement to configure 2 center frequencies for each 5G cell.
New Radio Absolute Radio Frequency Channel Number (NR-ARFCN).
Global Synchronisation Channel Number (GSCN).
NR-ARFCN is applicable to the channel bandwidth.
GSCN is applicable to the Synchronisation Signals / PBCH Block.
NR-ARFCN uses a fine raster to provide flexibility.
GSCN uses a coarse raster to reduce cell search times.
Requirement to know the selected SS/PBCH frequency in terms of both GSCN and ARFCN numbering.
3GPP has specified a ‘Global Frequency Raster’ for the NR-ARFCN
Each operating band uses a subset of the carriers belonging to the ‘Global Frequency Raster’
The ‘Global Frequency Raster’ has a resolution which depends upon the frequency range
The position of the SS/PBCH within the channel bandwidth can be configured
unlike 4G which always broadcasts the PBCH in the center of the channel.
The GSCN must be selected to ensure:
SS/PBCH is fully accommodated within the channel bandwidth.
subcarrier alignment is achieved between the SS/PBCH Block and the channel.
Hope this helps…
The raster step size for the GSCN depends upon the frequency range
1.2 MHz @ freq < 3 GHz
1.44 MHz @ freq > 3 GHz, < 24.25 GHz
17.28 MHz @ freq > 24.25 GHz