The UTRA Absolute Radio Frequency Channel Number (UARFCN) is a numerical identifier assigned to each individual radio channel within the frequency bands used by the UMTS (Universal Mobile Telecommunications System) UTRA (UMTS Terrestrial Radio Access). UARFCN is used to uniquely represent and calculate the carrier frequency of a specific radio channel. This numbering scheme helps identify and manage the numerous channels operating within the UMTS network.

The UARFCN is calculated based on the following formulas:

For the uplink (NU): NU = 5 * (FUL – FUL_Offset), where FUL_low ≤ FUL ≤ FUL_high

For the downlink (ND): ND = 5 * (FDL – FDL_Offset), where FDL_low ≤ FDL ≤ FDL_high

Here’s what each of these components represents:

• NU and ND: These are the UARFCNs for the uplink and downlink, respectively.
• FUL and FDL: These variables represent the carrier frequencies (in MHz) for the uplink and downlink, respectively, of the specific radio channel.
• FUL_Offset, FUL_low, FUL_high, FDL_Offset, FDL_low, FDL_high: These parameters are defined for each operating band within the UMTS UTRA. They specify the offset values and frequency ranges associated with that particular band. These values are standardized by 3GPP (3rd Generation Partnership Project) in the document TS 25.101.

In summary, the UARFCN is a standardized numbering scheme used to identify and calculate the carrier frequencies of individual radio channels within the UMTS UTRA system. It ensures that each channel within different frequency bands can be uniquely represented and easily managed within the UMTS network, facilitating efficient communication and channel allocation.