- Replaced ITTI message queues with notifiedFIFO for RRC to MAC communication in UE.
- Enables correct message delivery to multiple MAC instances running in parallel threads.
- Introduced `nr_mac_rrc_message_t` union for MAC-RRC messages.
- Updated all relevant message handling and initialization code to use notifiedFIFO.
- Use MAX_NUM_NR_UE_INST in NR UE MAC to control number of MAC instances.
- Modify the MAC interface slightly so that nr_l2_init_ue only initializes one instance
Use MAX_NUM_NR_UE_INST for number of NR UE RRC instances. Change the RRC
interface slightly so nr_rrc_init_ue initializes only one RRC instance pointed
to by the id given to the function
continuously update SIB19 information for rfsim NTN LEO scenarios
Contains mainly these changes:
- gNB: add function nr_update_sib19() allowing to update SIB19
information
- rfsimulator: update SIB19 contents every frame for LEO channel
simulations
- NR UE: improve initial timing advance calculation from SIB19
Before, we only considered ta_Common_r17 and the SAT position from SIB19
to compute the initial timing advance value. This is good enough if the
satellite does not move too fast (e.g. GEO satellite).
Now we also consider ta_CommonDrift_r17, ta_CommonDriftVariant_r17 and
the SAT velocity together with the epoch time from SIB19. This improves
the accuracy of the initial TA computation, esp. for LEO satellite
scenarios.
The implementation is limited to epoch times that are not more than 5.12 seconds in the future (allowed are up to 10.24 seconds)
and ntn-UlSyncValidityDuration < 5.12 seconds (allowed are up to 90 seconds).
To fix this limitation, the hyper frame number HFN has to be introduced at the OAI UE!
Before, we only considered ta_Common_r17 and the SAT position from SIB19 to compute the initial timing advance value.
This is good enough if the satellite does not move too fast (e.g. GEO satellite).
Now we also consider ta_CommonDrift_r17 and the SAT velocity together with the epoch time from SIB19.
This improves the accuracy of the initial TA computation, esp. for LEO satellite scenarios.
During reestablishment the UE goes back to not synchronized state.
While the synchronizatin is running, we trash frames using the function readFrame().
And when we successfully synchronize, we skip samples to align with the start of the frame using syncInFrame().
In rfsimulator mode, both of these functions send dummy data using the function dummyWrite().
Unfortunately, the writeTimestamp provided to that function was always assuming a duration from RX to TX of NR_UE_CAPABILITY_SLOT_RX_TO_TX.
But in NTN mode, this value is changed when receiving SIB19.
Therefore we have to consider this changed value instead of the static one.
Fix data race in NR UE MSG3 scheduling
Fixed a data race between DL processing of RAR and UL scheduler, which might
result in dropping MSG3.
It was possible that the UL scheduler for the UL slot which RAR indicates as
MSG3 slot was already run by the time the RAR was decoded.
Therefore when DCI for RAR is decoded, assume worst case and halt UL scheduler
for next slot until RAR is decoded solving the data race. This also in turn
halts all later scheduling due to sequential nature of the UL scheduler calls.
Closes#962
imscope updates
- Add CSV export button to imscope
- Add extra cache for IQ data in imscope record thread so that UE time domain
data can be kept until PDSCH is decoded.
- Add metadata to UE time domain samples scope
- Add UE pdsch pre-compensation IQ and PDSCH channel estimates
Fixed a data race between DL processing of RAR and UL scheduler, which
might result in dropping MSG3.
It was possible that the UL scheduler for the UL slot which RAR
indicates as MSG3 slot was already run by the time the RAR was decoded.
Therefore when DCI for RAR is decoded, assume worst case and halt the
earliest corresponding UL scheduler call until RAR is decoded solving
the data race. This also in turn halts all later scheduling due to
sequential nature of the UL scheduler calls.
Due to different processing requirements on different CPUs it might
be beneficial to enable the users to set the number of UL/DL actors.
Allow disabling UL/DL actor frameworks and processing inline or
setting the number of DL/UL threads with --num-ul-actors/num-dl-actors
This was tested to work with 0 UL/DL actors with rfsim.
fix NTN LEO scenario
NR UE: in nr_slot_fep() perform FO compensation in local tmp_dft_in
array instead of global rxdata array.
This avoids problems if nr_slot_fep() is called more than once for an
OFDM symbol.
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
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
This commit introduces support for concurrent UL slot processing
Key changes:
- Increased number of UL actors from 1 to 2
- fix several issues related to writing to global variables inside
processSlotTX
- Ensure in-order execution of if_module calls by utilizing the
preexisting dynamic_barrier structure.
Remove memset of the UE TX time domain samples array after trx_write in
RU_write()
This memset is unnecessary and can break openair0 libraries. Some
functionalities, e.g. usrp_lib write_thread expect the samples to be
present in the array after trx_write returns.
The array is always set before being sent either in idft or using memset
so there is no risk of sending the same data twice.
K-offset updated with configured sub carrier spacing
According to 38.331 , cell specific K-OFFSET provided in SIB19 is provided in
number of slots as per 15Khz SCS Koffset before being applied, needs to be
updated to the slots according to the configured subcarrier spacing.
According to 38.331 , cell specific K-OFFSET provided in SIB19 is provided in number of slots as per 15Khz SCS
Koffset before being applied, needs to be updated to the slots according to the configured subcarrier spacing.
Handle N_TA_offset update the same way timing advance changes are handled:
modify writeBlockSize to ensure continuous transmission. Also address possible
data races by making sure the new timing_advance/N_TA_offset is only read
once from global memory.
This prevents the UE to use an outdated timing_advance after a re-sync. It prevents the UE to send a PRACH with a wrong TA, thus preventing a RAPID mismatch in Msg2 (example: '[UE 0][RAPROC][0.0] Received RAR preamble (29) doesn't match the intended RAPID (30)')
fix NTN LEO scenarios
- gNB: add support for NTN parameter ta-CommonDrift-r17
- NR UE: fix application of NTN TA information
- NR UE: add command line parameter ntn-initial-time-drift to compensate
time drift during initial sync
- NR UE: fix writeTimestamp inconsistencies
- NR UE: add MAC state UE_RECEIVING_SIB ensuring to start RA only after
successfully receiving SIBs
- rfsimulator: update earth radius for LEO simulation to match UE
position in ue.conf file
- update conf files for NTN LEO scenario
- update description how to run NTN scenarios in RUNMODEM.md
- fix: ta-Common is a round-trip-time, not a one-way delay
- NR UE: simplify calculation of next_tx_slot_and_frame by moving up
assignment of duration_rx_to_tx
- cellbarredNTN indicates notbarred in SIB1 if NTN access is available
- Removed b66 NTN and enabled B254 NTN conf file in CI
- NR UE: RRC layer now explicitly tells MAC layer when the RA procedure
can be started
- move NTN LEO config to band 254 and update doc/RUNMODEM.md
Closes#901
The "writeTimestamp inconsistencies" are coming from the fact that during the actual processing we write `N_TA_offset` samples _and_ `NR_UE_CAPABILITY_SLOT_RX_TO_TX` slots ahead,
but both was not corrently considered in readFrame() and syncInFrame().
Therefore, there was always a warning about a gap in write timestamps as soon the actual processing starts.
The value of ntn_init_time_drift is used at initial sync to compensate for the time drift during initial sync detection.
To perform the initial time and frequency sync, the OAI UE currently takes a snapshot of two frames and then performes PSS correlation, SSS detection and MIB decoding.
Doing this takes much time, several tens of ms. During that time, the DL timing drifts so much, that we immediatedly lose sync again.
Therefore the current OAI UE implementation needs to know the drift rate to compensate for this drift, as we are "blind" while performing the initial sync.
To my undestanding, commercial UEs simply have a faster initial sync, so the DL timing will not drift away too much while performing that initial sync.
Laurent THOMAS