5G Absolute Radio Frequency Channel Number (NR-ARFCN)

5G, LTE, New Radio, Tech Fundas

An Absolute Radio-Frequency Channel Number (ARFCN) is a code that specifies the a pair of reference frequencies used for transmission and reception in radio system. In a FDD system one ARFCN number is required for downlink and another for uplink  as downlink and uplink frequencies are different while for TDD system only one ARFCN number is enough as downlink and uplink frequency remains same.

Term ARFCN started from GSM and evolved with the new technologies like it was know as UARFCN for UMTS/WCDMA, named as EARFCN for E-UTAR/LTE and now renamed as  NR-ARFCN for 5G/New Radio. NR-ARFCNs for 5G new radio are defined in 3GPP specification 38.101-1 and 38.101-2.

NR Band Types:

  1. Frequency Division Duplex (FDD) Band
  2. Time Division Duplex (TDD) Band
  3. Supplement Downlink (SDL) Bands
  4. Supplement Uplink (SUL) Bands

NR-ARFCN Per Operating Band (FR1 < 6GHz)

NR  Band Band Alias Duplex Mode ΔFRaster
(kHz)
Uplink Range of NREF
(First – <Step size> – Last)
Downlink Range of NREF
(First – <Step size> – Last
n1  2100 FDD 100 384000 – <20> – 396000 422000 – <20> – 434000
n2  1900 PCS FDD 100 370000 – <20> – 382000 386000 – <20> – 398000
n3  1800 FDD 100 342000 – <20> – 357000 361000 – <20> – 376000
n5  850 FDD 100 164800 – <20> – 169800 173800 – <20> – 178800
n7  2600 FDD 100 500000 – <20> – 514000 524000 – <20> – 538000
n8  900 FDD 100 176000 – <20> – 183000 185000 – <20> – 192000
n20  800 FDD 100 166400 – <20> – 172400 158200 – <20> – 164200
n28  700 APT FDD 100 140600 – <20> – 149600 151600 – <20> – 160600
n38  TD 2600 TDD 100 514000 – <20> – 524000 514000 – <20> – 524000
n41  TD 2500 TDD 15 499200 – <3> – 537999 499200 – <3> – 537999
n50  TD 1500+ TDD 100 286400 – <20> – 303400 286400 – <20> – 303400
n51  TD 1500- TDD 100 285400 – <20> – 286400 285400 – <20> – 286400
n66  AWS-3 FDD 100 342000 – <20> – 356000 422000 – <20> – 440000
n70  AWS-4 FDD 100 339000 – <20> – 342000 399000 – <20> – 404000
n71  600 FDD 100 132600 – <20> – 139600 123400 – <20> – 130400
n74  L-Band FDD 100 285400 – <20> – 294000 295000 – <20> – 303600
n75  DL 1500+ SDL 100 N/A 286400 – <20> – 303400
n76  DL 1500- SDL 100 N/A 285400 – <20> – 286400
n77  TD 3700 TDD 15 620000 – <1> – 680000 620000 – <1> – 680000
n78  TD 3500 TDD 15 620000 – <1> – 653333 620000 – <1> – 653333
n79  TD 4500 TDD 15 693334 – <1> – 733333 693334 – <1> – 733333
n80  UL 1800 SUL 100 342000 – <20> – 357000 N/A
n81  UL 900 SUL 100 176000 – <20> – 183000 N/A
n82  UL 800 SUL 100 166400 – <20> – 172400 N/A
n83  UL 700 SUL 100 140600 – <20> –149600 N/A
n84  UL 2100 SUL 100 384000 – <20> – 396000 N/A

NR-ARFCN Per Operating Band (FR2 > 6GHz)

NR  Band Band Alias Duplex Mode ΔFRaster
(kHz)
Uplink Range of NREF
(First – <Step size> – Last)
Downlink Range of NREF
(First – <Step size> – Last
n257  28 GHz TDD 60 2054167 – <1> – 2104166 2054167 – <1> – 2104166
n258  26 GHz TDD 60 2016667 – <1> – 2070833 2016667 – <1> – 2070833
n260  39 GHz TDD 60 2229167 – <1> – 2279166 2229167 – <1> – 2279166

NR-ARFCN Calculation:

The relation between the NR-ARFCN and the RF reference frequency FREF in MHz for the downlink and uplink is given by the following equation, where FREF-Offs and NRef-Offs  depend on frequency range are given in table below  and NREF is the NR-ARFCN.

  • FREF = FREF-Offs + ΔFGlobal (NREF – NREF-Offs)                   (i)
  • NREF = NREF-Offs +  (FREF – FREF-Offs) / ΔFGlobal                  (ii) 

 Equation (i) can be used when you need to calculate center frequency FREF  for given NR-ARFCN. Equation (ii) can be used when you need to calculate NR-ARFCN for a given center frequency.

Frequency range ΔFGlobal FREF-Offs [MHz] NREF-Offs Range of NREF
0 – 3000 MHz 5 kHz 0 MHz 0 0 – 599999
3000 – 24250 MHz 15 kHz 3000 MHz 600000 600000 – 2016666
24250 – 100000 MHz 60 kHz 24250 MHz 2016667 2016667 – 3279167

NR-ARFCN Calculation Example:

Lets consider given frequency is 2120 MHz from NR band n1, then NREF  (NR-ARFCN) can be calculated using above equation (ii). Get all the value for equation:

  • NREF-Offs  = 0                           (Because 2120 is with in the range of 0 – 3000 MHz)
  • FREF             = 2120 MHz           (Given Frequency)
  • FREF-Offs    = 0                         (Because 2120 is with in the range of 0 – 3000 MHz)
  • ΔFGlobal     = 5KHz 

Putting all value in equation

  • NREF = 0 +  (2120 MHz – 0 ) / 5KHz
  • NREF = 2120 MHz/ 5KHz   = 424000 will be the NR-ARFCN

Reference Frequency Calculation Example:
Lets consider given NR-ARFCN is 670000 from NR band n77, then FREF  (center frequency) can be calculated using above equation (i). Get all the value for equation:

  •  NREF-Offs  = 600000                     (Because 670000 is with in the range of 600000 – 2016666)
  • NREF             = 670000                  (Given NR-ARFCN)
  • FREF-Offs    = 3000 MHz                (Because 670000 is with in the range of 600000 – 2016666)
  • ΔFGlobal     = 15KHz 

Putting all values in equation

  • FREF = 3000 MHz + 15KHz x (670000 – 600000)
  • FREF = 3000 MHz + 15KHz x 70000
  • FREF = 3000 MHz + 1050 MHz = 4050 MHz will be the center frequency