5G NR Band Lookup — n78 Frequencies, NR-ARFCN & Resource Blocks

Every 5G NR carrier sits in an operating band defined by 3GPP, and every carrier frequency is named by a channel number, the NR-ARFCN. This calculator reads both from the Release 18 tables: TS 38.101-1 for frequency range 1 (FR1, 410 to 7125 MHz), TS 38.101-2 for frequency range 2 (FR2, 24.25 to 71 GHz) and the global raster of TS 38.104.

Operating bands and duplex

Each band row gives an uplink range, a downlink range and a duplex mode. In an FDD band the two ranges differ, and the duplex spacing is the distance between their lower edges: band n1 transmits from the handset at 1920 to 1980 MHz and receives at 2110 to 2170 MHz, 190 MHz apart. In a TDD band such as n78, 3300 to 3800 MHz, both directions share one range and the spacing is 0. Supplementary downlink (SDL) and supplementary uplink (SUL) bands carry only one direction, so the other is shown as absent rather than as zero. A few bands, n91 to n94 and n109, are variable-duplex: their uplink and downlink ranges are used independently, and they have no fixed spacing. The n78 reference page and the n257 reference page describe those two bands in more detail.

NR-ARFCN and the global raster

The NR-ARFCN $N_{REF}$ runs from 0 to 3279165 and maps to the RF reference frequency through three raster ranges (TS 38.104, Table 5.4.2.1-1):

Below 3000 MHz the step $\Delta F_{Global}$ is 5 kHz with no offset. From 3000 MHz to 24.25 GHz it is 15 kHz, counted from 3000 MHz at channel 600000. Above that it is 60 kHz, counted from 24250.08 MHz at channel 2016667. NR-ARFCN 636666 is therefore $3000 + 0.015 \times 36666 = 3549.99$ MHz. A band uses only part of the raster, its channel raster: every channel, or every second channel, within the band's NR-ARFCN range (Table 5.4.2.3-1). Band n78 runs from 620000 to 653333 on its 15 kHz raster, and on every second channel from 620000 on its 30 kHz raster.

Resource blocks

A resource block is 12 subcarriers. The largest number that fits a channel, $N_{RB}$, depends on the channel bandwidth and the subcarrier spacing (SCS) and is tabulated in Table 5.3.2-1 of each part. A 100 MHz channel at 30 kHz holds 273 resource blocks, which occupy $273 \times 12 \times 30$ kHz = 98.28 MHz; the rest is guard band. Some combinations do not exist, such as 100 MHz at 15 kHz in FR1, and are shown as absent.

Validity

The tables are those of 3GPP Release 18 (TS 38.101-1 V18.15.0, TS 38.101-2 V18.14.0 and TS 38.104 V18.15.0); a band added in a later release is reported as unknown. The resource-block count comes from the general table, and whether a particular band allows that bandwidth (Table 5.3.5-1 of each part) is not checked. NR-ARFCN values above 3279165 and frequencies above 100 GHz lie off the global raster: they are converted by extending its last step and shown with a warning.