Global Synchronisation Channel Number not just helps in decoding SSBurst but also reducing the number of decoding failure attempts. The variance between ARFCN and GSCN is the step size. ARFCN carries smaller step size contrast to GSCN so it not only helps to decode faster and also reduce the number of failure attempts to decode SSB.
From the table below shows the GSCN ranges for each frequency range and calculation of SSB positions in FR1 and FR2.
SSB locations are always aligned with channel bandwidth ie PRBs. From the table where for FR1 ranging from 3000-24250 MHz,
For example: As per procedure SSB location for FR1 range i.e 3000MHz – 24250MHz ==> 3000MHz + N*1.44MHz here N ranges from 0 to 14756. Here need to pick N and M values in such a way that this SSB frequency should be SCS/PRB aligned, shouldn’t consider any other values in-between.
Ref: 3GPP 38.104
