> UMTS >
UMTS must operate in a frequency band defined
by 3GPP TS 25.104. In FDD mode, the paired bands must have a
minimum of 30MHz separation between the UL/DL. The Up-Link (UL) refers to the transmission from the phone to the
base station, and is always the lower frequency, since the phone
has a lower output power than the base station, and lower
frequencies help the signal travel farther.
Values taken from 3GPP TS25.104
The UARFCN (UTRA Absolute Radio Frequency Channel Number)
is the channel number representing the full 5 MHz UMTS carrier. Only 3.84MHz is used for
transmission, while the 116 kHz acts as a
built-in guard-band to adjacent UARFCN's (580kHz + 3840kHz +
580kHz = 5MHz). If an operator owns the adjacent frequency
bands, it is possible to reduce the size of the UMTS carrier
from 5MHz to 4.4 or 4.2 MHZ, but this is not recommended.
UARFCN channel number is calculated according to it's frequency.
If no offset is used, the frequency is simply multiplied by 5 to
get the UARFCN (ex: 2132.8 MHZ * 5 = UARFCN 10664) If an
offset is used the offset must be first subtracted from the
RadioRaiders UARFCN Calc
In order to quickly translate the Down-Link UARFCN to it's
actual frequencies, RadioRaiders developed an on-line calculator
to quickly perform the calculation. Just enter the DownLink UARFCN and
frequency bands and other info will be returned.
Enter DL UARFCN:
Theres also a downloadable version of the tool (.exe) that should work on any
version of Windows. You may need .NET installed, which you can
download for free from Microsoft here:
Download RadioRaiders UARFCN calc here:
Note: Correction to tool made on 04.Feb.2009, previous version
had error in Bands X to XIII. Please download new version.
Screen-shot of UARFCN calc: