NR ARFCN Explained – 5G NR Absolute Radio Frequency Channel Number

The NR ARFCN (Absolute Radio Frequency Channel Number) is a fundamental parameter used in 5G New Radio (NR) systems to identify the exact carrier frequency used by a cell.

In simple terms, ARFCN provides a numeric representation of a radio frequency so that the network and the user equipment (UE) can communicate using standardized channel numbering.

If you need to convert between frequency and ARFCN, you can use the NR ARFCN Calculator available on this site.

Why ARFCN Is Important in 5G Networks

Modern cellular networks operate across many frequency bands. Instead of referencing raw frequencies such as 3500 MHz, networks use a channel number system.

This approach simplifies:

• frequency planning
• cell configuration
• device scanning
• mobility management

The ARFCN ensures that UEs and base stations refer to frequencies consistently.

Frequency	ARFCN
3500 MHz	~620000
3600 MHz	~640000

These numbers are used in signaling messages exchanged between the UE and the network.

What is NR ARFCN?

NR ARFCN stands for:

NR Absolute Radio Frequency Channel Number

It uniquely identifies the downlink or uplink carrier frequency in a 5G system.

The concept was introduced as part of 5G NR radio specifications defined by the 3rd Generation Partnership Project in TS 38.104.

ARFCN is used by:

• gNB (5G base station)
• UE (user equipment)
• network planning tools

NR Frequency Ranges

5G NR operates across two major frequency ranges.

Frequency Range	Name	Frequency
FR1	Sub-6 GHz	410 MHz - 7125 MHz
FR2	mmWave	24.25 GHz - 52.6 GHz

Each range uses different ARFCN spacing rules.

NR ARFCN Formula

The relationship between frequency and ARFCN is defined by the equation:

NR-ARFCN = (Fref - Foffset) / DeltaFglobal + Noffset

Where:

Parameter	Description
Fref	reference frequency
Foffset	frequency offset
DeltaFglobal	global frequency step
Noffset	ARFCN offset

These parameters depend on the frequency range.

ARFCN Calculation for FR1 (Sub-6 GHz)

For most 5G deployments such as n78 or n41, the calculation uses:

Parameter	Value
DeltaFglobal	5 kHz
Noffset	0
Frequency range	410-7125 MHz

Example calculation:

Frequency = 3500 MHz

Step size = 5 kHz

ARFCN ~= 620000

This ARFCN represents the carrier channel used by the gNB.

ARFCN Calculation for FR2 (mmWave)

For mmWave frequencies:

Parameter	Value
DeltaFglobal	60 kHz
Noffset	2016667

Example:

Frequency = 28 GHz

The resulting ARFCN falls in the 2 million range.

Example NR ARFCN Calculation

Let's calculate the ARFCN for a common 5G band n78 carrier.

Frequency:

3500 MHz

Step size:

5 kHz

Result:

ARFCN ~= 620000

Using the calculator provides the exact value instantly.

How ARFCN Is Used in 5G Signaling

ARFCN appears in several radio configuration parameters and signaling messages.

RRC Messages

Examples of messages where ARFCN appears:

• RRC Setup
• RRC Reconfiguration
• System Information Blocks

These messages configure the UE with the downlink and uplink carrier frequencies.

SIB1 Frequency Information

Within SIB1, the network broadcasts frequency parameters including:

• NR ARFCN
• subcarrier spacing
• bandwidth

This allows UEs to synchronize and access the cell.

SystemInformationBlockType1 ::= {
  cellAccessRelatedInfo {
      plmn-IdentityList {
         {
            plmn-Identity {
                mcc { 2,6,0 },
                mnc { 0,1 }
            },
            cellReservedForOperatorUse notReserved
         }
      },
      trackingAreaCode '0001'H,
      cellIdentity '0000000010101010'B,
      cellBarred notBarred,
      intraFreqReselection allowed
  },

  cellSelectionInfo {
      q-RxLevMin -65,
      q-RxLevMinOffset 0
  },

  p-Max 23,

  freqBandIndicatorNR 78,

  servingCellConfigCommon {
     ssb-PositionsInBurst {
         shortBitmap '10000000'B
     },

     ssb-PeriodicityServingCell ms20,

     dmrs-TypeA-Position pos2,

     subcarrierSpacingCommon scs30or120,

     ss-PBCH-BlockPower -18
  },

  ue-TimersAndConstants {
      t300 ms1000,
      t301 ms1000,
      t310 ms1000,
      n310 n1,
      t311 ms10000,
      n311 n1
  },

  connEstFailureControl {
      connEstFailCount 1,
      connEstFailOffset 1,
      connEstFailThreshold 4
  }
}

Measurement Configuration

During mobility procedures, ARFCN identifies neighboring cells.

Example parameters include:

• carrierFrequency
• measObjectNR

These help the UE measure signal quality on different frequencies.

DL-DCCH-Message ::= {
  message c1 : rrcReconfiguration : {
    rrc-TransactionIdentifier 1,
    criticalExtensions rrcReconfiguration : {
      radioBearerConfig NULL,
      secondaryCellGroup NULL,
      measConfig {
        measObjectToAddModList {
          {
            measObjectId 1,
            measObject measObjectNR : {
              ssbFrequency 631968,
              ssbSubcarrierSpacing kHz30,
              smtc1 {
                periodicityAndOffset sf20 : 0,
                duration sf5
              },
              quantityConfigIndex 1,
              offsetMO {
                rsrpOffsetSSB 0,
                rsrqOffsetSSB 0,
                sinrOffsetSSB 0
              },
              cellsToRemoveList { },
              cellsToAddModList {
                {
                  physCellId 100,
                  cellIndividualOffset {
                    rsrpOffsetSSB 0,
                    rsrqOffsetSSB 0,
                    sinrOffsetSSB 0
                  }
                }
              },
              excludeCellsToRemoveList { },
              excludeCellsToAddModList { }
            }
          }
        },

        reportConfigToAddModList {
          {
            reportConfigId 1,
            reportConfig reportConfigNR : {
              reportType eventTriggered : {
                eventId eventA3 : {
                  a3-Offset 6,
                  reportOnLeave FALSE,
                  hysteresis 2,
                  timeToTrigger ms160,
                  useWhiteCellList FALSE
                }
              },
              rsType ssb,
              reportInterval ms480,
              reportAmount r4,
              reportQuantity {
                rsrp TRUE,
                rsrq TRUE,
                sinr FALSE
              },
              maxNrofRS-IndexesToReport 4,
              maxReportCells 4,
              includeBeamMeasurements TRUE
            }
          }
        },

        measIdToAddModList {
          {
            measId 1,
            measObjectId 1,
            reportConfigId 1
          }
        },

        quantityConfig {
          quantityConfigRS-Indexes {
            ssb-FilterConfig {
              filterCoefficient fc4
            }
          }
        },

        measGapConfig setup : {
          gapOffset gp1 : 20
        }

      },
      lateNonCriticalExtension '',
      nonCriticalExtension { }
    }
  }
}

ARFCN vs GSCN

Another important 5G parameter is GSCN (Global Synchronization Channel Number).

Parameter	Purpose
ARFCN	identifies carrier frequency
GSCN	identifies synchronization signal frequency

GSCN is specifically used for SSB detection during cell search.

Once the UE detects the SSB using GSCN, it learns the ARFCN used for the carrier.

Example Bands Using ARFCN

Some common 5G bands and their frequencies:

Band	Frequency	Typical ARFCN
n78	3300-3800 MHz	~620000
n41	2496-2690 MHz	~499200
n258	24.25-27.5 GHz	>2000000

Network engineers use ARFCN values when configuring cells in the base station.

Why Engineers Use ARFCN Instead of Frequency

Using numeric channel identifiers simplifies network operations.

Advantages include:

• consistent configuration
• easier spectrum planning
• standardized signaling
• simplified device scanning

Instead of specifying 3500 MHz, engineers can use ARFCN 620000.

Practical Example in Network Planning

A network engineer deploying a 5G carrier might configure:

Band: n78
Bandwidth: 100 MHz
Carrier frequency: 3500 MHz
ARFCN: 620000

This value is entered in the gNB configuration file.

Devices connecting to the network then use this ARFCN during:

• cell selection
• handover measurements
• carrier aggregation

When to Use the NR ARFCN Calculator

The calculator is useful for:

• converting frequency to ARFCN
• converting ARFCN to frequency
• planning NR carriers
• validating network configurations
• studying 5G radio parameters

Students and engineers frequently use it when working with radio network planning tools or base station configuration files.

Related 5G Calculators

You may also find these tools useful:

• 5G Throughput Calculator
• NR GSCN Calculator
• RF Link Budget Calculator
• Free Space Path Loss Calculator

These tools help engineers design and analyze wireless systems.

References

The ARFCN numbering scheme is defined in the following specifications:

• 3rd Generation Partnership Project TS 38.104 - NR Base Station Radio Transmission and Reception
• 3rd Generation Partnership Project TS 38.211 - NR Physical Channels and Modulation
• 3rd Generation Partnership Project TS 38.331 - NR Radio Resource Control

Summary

The NR ARFCN is a standardized channel number used in 5G networks to represent the carrier frequency. It plays a key role in:

• cell configuration
• UE frequency scanning
• mobility management
• radio measurements

By converting frequencies to ARFCN values, engineers ensure that 5G devices and networks operate with a consistent and standardized channel numbering system.

Use the NR ARFCN Calculator above to quickly convert between frequency and ARFCN for any 5G NR band.