Merge remote-tracking branch 'origin/ntn_leo_freq_comp' into integration_2025_w15 (!3355)
NR UE: add support for continuous frequency offset compensation (in particular NTN LEO Doppler)
- move function add_noise() to file
openair1/SIMULATION/TOOLS/phase_noise.c
- refactor (co)sinus calculation out of phase_noise() into get_sin_cos()
in nr_common.c
- NR UE: continuously estimate the frequency offset using PBCH DMRS
- NR UE: add command line parameter --initial-fo to specify known
initial frequency offset
- NR UE: add support for continuous DL frequency offset compensation
--cont-fo-comp
- NR UE: add support for continuous UL frequency offset
pre-compensation. Depending on the main source of frequency offset,
pre-compensate the UL frequency offset (FO) accordingly. Therefore
modify the flag --cont-fo-comp to accept an integer value, where
* 1 specifies, that the main FO contribution comes from the accuracy of the local oscillator (LO)
* 2 specifies, that the main FO contribution comes from Doppler shift
- NR UE: add PI controller to continuous frequency offset compensation
- rfsimulator: enable and correct NTN LEO doppler simulation
- use SIMD to speed up nr_fo_compensation()
- Extend NTN LEO example in RUNMODEM.md to include continuous Doppler
compensation
- NR UE: in nr_adjust_synch_ue() extend the peak search to +/- cyclic
prefix size, esp. for LEO NTN scenarios the timing drifts during
initial sync, which is mostly compensated with
--ntn-initial-time-drift. But there might be a residual time offset,
and by extending the peak search window we make this more tolerant.
- NR UE: remove unused nr_slot_tx_offset, it is unused since commit
f3e60a14
- NR UE: remove now unnecessary local variable
update_ntn_system_information, directly use
UE->ntn_config_message->update instead
This commit is contained in:
Robert Schmidt
+16
-2
@@ -136,7 +136,15 @@ Here are some useful command line options for the NR UE:
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| Parameter | Description |
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|--------------------------|---------------------------------------------------------------------------------------------------------------|
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| `--ue-scan-carrier` | Scan for cells in current bandwidth. This option can be used if the SSB position of the gNB is unknown. If multiple cells are detected, the UE will try to connect to the first cell. By default, this option is disabled and the UE attempts to only decode SSB given by `--ssb`. |
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| `--ue-fo-compensation` | Enables the frequency offset compensation at the UE. Useful when running over the air and/or without an external clock/time source. |
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| `--ue-fo-compensation` | Enables the initial frequency offset compensation at the UE. Useful when running over the air and/or without an external clock/time source. |
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| `--cont-fo-comp` | Enables the continuous frequency offset (FO) estimation and compensation. Parameter value `1` specifies that the main FO contribution comes from the local oscillator's (LO) accuracy. Parameter value `2` specifies that the main FO contribution comes from Doppler shift. |
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| `--initial-fo` | Sets the known initial frequency offset. Useful especially with large Doppler frequency, e.g. LEO satellite. |
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| `--freq-sync-P` | Sets the coefficient for the Proportional part of the PI-controller for the continuous frequency offset compensation. Default value 0.01. |
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| `--freq-sync-I` | Sets the coefficient for the Integrating part of the PI-controller for the continuous frequency offset compensation. Default value 0.001. |
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| `--ntn-initial-time-drift` | Sets the initial NTN DL time drift (feeder link and service link), given in µs/s. |
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| `--autonomous-ta` | Enables the autonomous TA update, based on DL drift (useful if main contribution to DL drift is movement, e.g. LEO satellite). |
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| `--time-sync-P` | Sets the coefficient for the Proportional part of the PI-controller for the time synchronization. Default value 0.5. |
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| `--time-sync-I` | Sets the coefficient for the Integrating part of the PI-controller for the time synchronization. Default value 0.0. |
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| `--usrp-args` | Equivalent to the `sdr_addrs` field in the gNB config file. Used to identify the USRP and set some basic parameters (like the clock source). |
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| `--clock-source` | Sets the clock source (internal or external). |
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| `--time-source` | Sets the time source (internal or external). |
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@@ -349,10 +357,16 @@ For LEO satellite scenarios, the parameter `--ntn-initial-time-drift` must be pr
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This parameter provides the drift rate of the complete DL timing (incl. feeder link and service link) in µs/s.
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Also, to perform an autonomous TA update based on the DL drift, the boolean parameter `--autonomous-ta` should be added in case of a LEO satellite scenario.
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For LEO satellite scenario we assume the LO to be very accurate and the main FO contribution comes from Doppler shift.
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Therefore, we use the command line parameter `--cont-fo-comp 2` to continuously compensate the DL Doppler and pre-compensate the UL Doppler.
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The initial Doppler frequency offset must be provided via command line with the parameter `--initial-fo`.
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For other information on optional NR UE command line options, please refer [here](#optional-nr-ue-command-line-options).
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So an example NR UE command for FDD, 5MHz BW, 15 kHz SCS, transparent LEO satellite 5G NR NTN is this:
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```
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cd cmake_targets
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sudo ./ran_build/build/nr-uesoftmodem -O ../targets/PROJECTS/GENERIC-NR-5GC/CONF/ue.conf --band 254 -C 2488400000 --CO -873500000 -r 25 --numerology 0 --ssb 60 --rfsim --rfsimulator.prop_delay 20 --rfsimulator.options chanmod --time-sync-I 0.1 --ntn-initial-time-drift -46 --autonomous-ta
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sudo ./ran_build/build/nr-uesoftmodem -O ../targets/PROJECTS/GENERIC-NR-5GC/CONF/ue.conf --band 254 -C 2488400000 --CO -873500000 -r 25 --numerology 0 --ssb 60 --rfsim --rfsimulator.prop_delay 20 --rfsimulator.options chanmod --time-sync-I 0.1 --ntn-initial-time-drift -46 --autonomous-ta --initial-fo 57340 --cont-fo-comp 2
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```
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# Specific OAI modes
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