Files
openairinterface5g/doc/gNB_frequency_setup.md
Robert Schmidt 8107939f08 Change OAI license to CSSL v1.0 (and others)
- all RAN code, CI code, configuration files, dockerfiles, in CSSL v1.0
- all deployment code (openshift, charts, ancillary files like shell
  scripts), in MIT
- documentation in CC-BY-4.0
- exceptions might apply and are listed in NOTICE
- there is a new LICENSES folder with all licenses
- CONTRIBUTIONS.md has been updated accordingly

For automated changes based on OAI PL v1.1:

    perl -i~ -0pe 's/\/\*.*Licensed to the OpenAirInterface.*openairinterface.org\n#?/\/*\n * SPDX-License-Identifier: LicenseRef-CSSL-1.0\n/s' **/*.{c,h,cpp}
    perl -i~ -0pe 's/\/\*.*Licensed to the OpenAirInterface.*openairinterface.org\n#?/\/*\n * SPDX-License-Identifier: LicenseRef-CSSL-1.0\n/s' **/*.ts
    perl -i~ -0pe 's/<!--.*Licensed to the OpenAirInterface.*openairinterface.org\n.*-->/<!-- SPDX-License-Identifier: LicenseRef-CSSL-1.0 -->/s' **/*.xml

The rest (cmake, files with missing license, cmake) manually.
2026-03-27 16:36:37 +01:00

83 lines
4.9 KiB
Markdown

<!-- SPDX-License-Identifier: CC-BY-4.0 -->
# 5G gNB Frequency Configuration
Configuring the frequency settings for a 5G gNB involves specifying multiple parameters in the gNB configuration file. This guide outlines the necessary parameters and provides step-by-step instructions for configuration.
[TOC]
## Configuration parameters
To configure the gNB with the required frequency and bandwidth, modify following parameters in the configuration file:
### `gNBs` Section
* `absoluteFrequencySSB`: ARFCN (frequency number) of the middle frequency of the SSB. This value must align with the NR frequency raster defined in TS 38.104, Section 5.4.3.1.
* Steps to compute this value are provided below.
* `dl_absoluteFrequencyPointA`: ARFCN (frequency number) for Point A, lowest subcarrier of the reference resource block (Common RB 0).
* Steps to compute this value are provided below.
* `dl_frequencyBand`: downlink NR frequency band number.
* `dl_subcarrierSpacing`: downlink subcarrier spacing.
* *Allowed values:* `0` = 15 kHz, `1` = 30 kHz, `2` = 60 kHz, `3` = 120 kHz
* `dl_carrierBandwidth`: number of PRBs for downlink.
* `initialDLBWPlocationAndBandwidth`: resource indicator value (RIV) of the initial BWP.
* Steps to compute this value are provided below.
* `initialDLBWPsubcarrierSpacing`: initial downlink BWP subcarrier spacing.
* *Allowed values:* `0` = 15 kHz, `1` = 30 kHz, `2` = 60 kHz, `3` = 120 kHz
* `initialDLBWPcontrolResourceSetZero`: CORESET0 index (valid configurations, based on SCS and frequency bandwith, are given in TS 38.213, Table 13.1 to Table 13.14).
* `ul_frequencyBand`: uplink NR frequency band number.
* `ul_absoluteFrequencyPointA`: ARFCN (frequency number) for Point A, lowest subcarrier of the reference resource block (Common RB 0).
* **Set only for FDD configurations.**
* Frequency separation between DL and UL channels for a specific 5G NR band is defined in 38.101-1 5.4.4-1 for FR1 bands and in 38.101-5 5.4.4-1 for FR1 NTN bands. `ul_absoluteFrequencyPointA` is calculated by substracting the given frequency offset from the `dl_absoluteFrequencyPointA`.
* `ul_carrierBandwidth`: number of PRBs for uplink.
* `initialULBWPlocationAndBandwidth`: resource indicator value (RIV) of the initial BWP.
* Steps to compute this value are provided below.
* `initialULBWPsubcarrierSpacing`: initial uplink BWP subcarrier spacing.
* *Allowed values:* `0` = 15 kHz, `1` = 30 kHz, `2` = 60 kHz, `3` = 120 kHz
* `subcarrierSpacing`: general subcarrier spacing for both DL and UL.
* *Allowed values:* `0` = 15 kHz, `1` = 30 kHz, `2` = 60 kHz, `3` = 120 kHz
### `RUs` Section
* `bands`: NR frequency band number for RU(s).
## Determining the ARFCN value for `absoluteFrequencySSB` and `dl_absoluteFrequencyPointA`
Follow these steps to find the ARFCN values for `absoluteFrequencySSB`, `dl_absoluteFrequencyPointA`, `initialDLBWPlocationAndBandwidth`, and `initialULBWPlocationAndBandwidth`:
1. Convert RU center frequency to ARFCN value
* Example tool: [5G NR ARFCN Calculator](https://5g-tools.com/5g-nr-arfcn-calculator/)
* Input the center frequency of the RU (in MHz) into the tool to calculate the ARFCN value.
2. Enter parameters into the online tool for NR Point A computation
* Example tool: [NR Reference Point A Tool](https://www.sqimway.com/nr_refA.php)
* Enter the NR frequency band, ARFCN value for center frequency (use the value calculated in step 1), subcarrier spacing, CORESET0 index (`initialDLBWPcontrolResourceSetZero` in the gNB config file) and bandwidth into the tool.
3. Obtain required values
* From the tool's output, use the following results for your configuration:
* Arfcn GSCN: This corresponds to `absoluteFrequencySSB` - value for `absoluteFrequencySSB` can be selected freely from the table, if `Coreset(0) check` is "ok".
* Point A Arfcnc: This corresponds to `dl_absoluteFrequencyPointA`.
* locationAndBandwidth full: Use this value for both `initialDLBWPlocationAndBandwidth` and `initialULBWPlocationAndBandwidth`.
4. Set `dl_absoluteFrequencyPointA`, `absoluteFrequencySSB`, `initialDLBWPlocationAndBandwidth`, and `initialULBWPlocationAndBandwidth` in the gNB configuration file
## Example calculation
1. Convert RU center frequency to ARFCN value
* Center frequency = 3450 MHz
* Center frequency ARFCN = 630000
2. Enter parameters into the online tool for NR Point A computation
* Open the [NR Reference Point A Tool](https://www.sqimway.com/nr_refA.php) and input the following values:
* Frequency band = n78
* NR Arfcn scan (center frequency) = 630000
* SCS = 30 kHz
* Bandwidth = 100 MHz
* Control ResourceSet Zero = 11
3. Obtain required values
* The tool provides following output values:
* Arfcn GSCN (`absoluteFrequencySSB`) = 630048
* Point A Arfcnc (`dl_absoluteFrequencyPointA`) = 626724
* locationAndBandwidth full (`initialDLBWPlocationAndBandwidth`) = 1099
* locationAndBandwidth full (`initialULBWPlocationAndBandwidth`) = 1099