ARFCN: Absolute radio frequency channel number
This is the number which specifies a pair of reference frequencies that are used in transmission and reception in a radio channel. for FDD there are ARFCNs and for TDD one ARFCN for both DL an d UL.
This number gives a direction on the location for point A, centre frequency and SSB possible location.
from the table below shows ARFCN start and end for each operating band and step size for decoding SSB. for example band N1 operates at 422000 to 434000 in DL and for UL 384000 and 396000 and a step size of 20 in both directions which helps to decode next possible location to find SSB.
Similarly for band 78 which is TDD band, can see same ARFCN values in both DL and UL directions.
Calculation of frequency from a ARFCN:
lets take ARFCN ref 632323 and see what is the frequency it maps to.
from the formula shown above Fref = Fref-offs + Fglobal*(Nref – Nref-off)
Fref = 3000MHz+ 15*(632323-600000) >>> 3000 + 484845 = 3484.86MHz
Spec ref: 38.101
