From bf210241bd619683bca4a91b93b26a9646789a99 Mon Sep 17 00:00:00 2001 From: Jaroslava Fiedlerova Date: Thu, 10 Oct 2024 15:45:15 +0200 Subject: [PATCH] doc: Add instructions for 5G NR gNB frequency configuration --- doc/README.md | 1 + doc/gNB_frequency_setup.md | 80 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 81 insertions(+) create mode 100644 doc/gNB_frequency_setup.md diff --git a/doc/README.md b/doc/README.md index 7fc28f061a..5e156434e9 100644 --- a/doc/README.md +++ b/doc/README.md @@ -54,6 +54,7 @@ There is some general information in the [OpenAirInterface Gitlab Wiki](https:// - [How to run the physical simulators](./physical-simulators.md) - [How to setup OAI with Nvidia Aerial and Foxconn](./Aerial_FAPI_Split_Tutorial.md) - [How to do a handover](./handover-tutorial.md) +- [How to setup gNB frequency](./gNB_frequency_setup.md) Legacy unmaintained files: - [`L2NFAPI_NOS1.md`](./L2NFAPI_NOS1.md), [`L2NFAPI_S1.md`](./L2NFAPI_S1.md): diff --git a/doc/gNB_frequency_setup.md b/doc/gNB_frequency_setup.md new file mode 100644 index 0000000000..8ef4a4f083 --- /dev/null +++ b/doc/gNB_frequency_setup.md @@ -0,0 +1,80 @@ +# 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 +