L1 RX: use queues instead of arrays and linear search for PUCCH, PUSCH, SRS, PRACH
This MR is an attempt to reduce the time L1 RX searches in array for the
next job to process, and instead use a queue. This queue is a FIFO,
because the various jobs (FAPI messages) to process come in order, and
need to be processed in order. The MR (hopefully, to be measured)
reduces the amount of time spent searching for the next UE (because the
next job is always at the beginning of the queue), and should scale
better for many UEs.
It does the following:
- introduce two helper libraries for (1) Frame.Slot calculation (sfn_t),
already introduced in !3521 (merged) commit 3102068e, and (2) a ring
buffer with fixed size
- use sfn_t and ring buffer (gNB->pucch_queue) to remove the linear
array for PUCCH (gNB->pucch)
- use sfn_t and ring buffer (gNB->pusch_queue) for some PUSCH lookups.
Because we need to still store PUSCH contexts, gNB->pusch is still
there
- use sfn_t and ring buffer (gNB->srs_queue) to remove the linear array
for SRS (gNB->srs)
- use sfn_t and ring buffers (gNB->prach_ru_queue and
gNB->prach_l1rx_queue) to remove the linear array for PRACH
(gNB->prach_list)
- some minor cleanups, e.g., additional loops over the PUSCH array,
using const, using pointers instead of indices, etc
Use two queues for PRACH processing:
- prach_ru_queue: pass jobs from TX thread (scheduler) to RU thread. For
split 8, the RU thread itself handles PRACH processing; for split 7.2,
it is the library that is responsible for handling PRACH messages (see
oran_fh_if4p5_south_in())
- prach_l1rx_queue: after jobs have been handled in RU thread, use this
queue to pass jobs to the RX thread. There, preamble detection is
performed, and RACH.indication FAPI messages are filled if a preamble
has been detected.
Together, these queues replace a linear search in a global array that
has been modified by three threads at the same time. The design ensures
that access now is thread-safe, and with less overhead.
Signed-off-by: Robert Schmidt <robert.schmidt@openairinterface.org>
Cleanup common_lib.h
This change reduces the number of dependecies of common_lib.h and simplifies
the task of implementing an external OAI radio library.
- 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.
Synchronize multiple gNBs by aligning the slot boundaries
Currently, we derive frame and slot number based on proc->timestamp_rx
using
proc->frame_rx = (proc->timestamp_rx / (fp->samples_per_subframe*10))&1023;
proc->tti_rx = get_slot_from_timestamp(proc->timestamp_rx, fp);
This ignores the samples
proc->timestamp_rx % fp->samples_per_frame
while computing the frame and slot number creating a mis-alignment with
the slot boundaries. A detailed description of the slot misalignment
in a pictorial representation can be seen in an attachment in the MR [1].
We fix this alignment issue by compensating these samples during the
first reception.
We can test the synchronization of the multiple gNBs from the estimated
ToAs from the PRS in the Downlink and the estimated ToAs from the SRS in
the Uplink using rfsim.
In order to test this, make sure you build gNB and nrUE along with the
telnetsrv flag using the option --build-lib telnetsrv.
Also, enable the following log in the function
nr_est_srs_timing_advance_offset() in
openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c to observe SRS ToAs
LOG_I(NR_PHY, "SRS estimatd ToA %d [RX ant %d]: TA offset %d, TA offset ns %d (max_val %ld, mean_val %ld, max_idx %d)\n", srs_toa, ant, *ta_offset, *ta_offset_nsec, max_val, mean_val, max_idx);
Furthermore, update the option Active_gNBs = 2; in
targets/PROJECTS/GENERIC-NR-5GC/CONF/ue.nr.prs.fr1.106prb.conf to enable
decoding PRS transmitted from two gNBs
To run:
nrUE:
sudo ./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 --uicc0.imsi 001010000000001 --rfsim --phy-test -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/ue.nr.prs.fr1.106prb.conf --rfsimulator.serveraddr server
gNB 0:
sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb0.prs.band78.fr1.106PRB.usrpx310.conf --gNBs.[0].min_rxtxtime 6 --rfsim --phy-test --rfsimulator.[0].serveraddr 127.0.0.1 --rfsimulator.[0].options chanmod --rfsimulator.[0].modelname AWGN --telnetsrv
gNB 1:
sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb1.prs.band78.fr1.106PRB.usrpx310.conf --gNBs.[0].min_rxtxtime 6 --rfsim --phy-test --rfsimulator.[0].serveraddr 127.0.0.1 --rfsimulator.[0].options chanmod --rfsimulator.[0].modelname AWGN --telnetsrv
When we run the nrUE, gNB0 and gNB1, we can see the following logs
nrUE:
[PHY] [gNB 0][rsc 0][Rx 0][sfn 976][slot 2] DL PRS ToA ==> 0.0 / 2048 samples, peak channel power -16.4 dBm, SNR +4.0 dB, rsrp -42.2 dBm
[PHY] [gNB 1][rsc 0][Rx 0][sfn 976][slot 3] DL PRS ToA ==> 0.0 / 2048 samples, peak channel power -16.4 dBm, SNR +4.0 dB, rsrp -42.2 dBm
gNB 0:
[NR_PHY] SRS estimatd ToA 0 [RX ant 0]: TA offset 31, TA offset ns 0 (max_val 99820162, mean_val 80176, max_idx 0)
gNB 1:
[NR_PHY] SRS estimatd ToA 0 [RX ant 0]: TA offset 31, TA offset ns 0 (max_val 98784562, mean_val 79369, max_idx 0)
From the above logs, when we run the rfsim and when no delays introduced, we can observe the following results
In the Downlink at the UE, the estimated ToAs using PRS from both gNB0
and gNB1 are 0 and in the uplink, the ToA estimated from the SRS
transmitted by the UE at both the gNBs are also 0. This indicates that
both the gNBs are synchronized along with their slot boundaries. We also
highlight that this is not the case in the current develop branch since
the slot boundaries are not aligned.
We also can test the multi gNB synchronization by introducing delays
using telnet as follows,
Introduce new_offset (delay) of 4 samples to the gNB 0 from UE in the
uplink as follows,
openairinterface5g$ echo rfsimu setdistance rfsimu_channel_enB0 20 | ncat --idle 1 127.0.0.80 9080
softmodem_gnb> rfsimu_setdistance_cmd: new_offset 4, new (exact) distance 19.518 m, new delay 0.000065 ms
Ncat: Idle timeout expired (1000 ms).
We can oberve this delay of 4 samples being reflected in the estimated
SRS ToAs at gNB 0 while not changing the ToA in gNB 1
[NR_PHY] SRS estimatd ToA 4 [RX ant 0]: TA offset 31, TA offset ns 65 (max_val 98803636, mean_val 79430, max_idx 8)
similarly, Introduce new_offset (delay) of 2 samples to the gNB 1 from
UE in the uplink as follows,
openairinterface5g$ echo rfsimu setdistance rfsimu_channel_enB0 10 | ncat --idle 1 127.0.0.81 9081
softmodem_gnb> rfsimu_setdistance_cmd: new_offset 2, new (exact) distance 9.759 m, new delay 0.000033 ms
Ncat: Idle timeout expired (1000 ms).
We can oberve this delay of 2 samples being reflected in the estimated
SRS ToAs at gNB 1 while not changing the ToA in gNB 0
[NR_PHY] SRS estimatd ToA 2 [RX ant 0]: TA offset 31, TA offset ns 32 (max_val 98962768, mean_val 79552, max_idx 4)
Closes#897
[1] https://gitlab.eurecom.fr/oai/openairinterface5g/-/merge_requests/3892
Remove L1 dependence from NR band number
L1 band information relied on get_band function that couldn't provide an
unambiguous result. Also there is no SCF compliant parameter for L1 and
generally we don't really need that information in L1.
The MR also remove a RU section that used nr_band but was never really
accessed in NR.
Currently, we derive frame and slot number based on `proc->timestamp_rx`
using
`proc->frame_rx = (proc->timestamp_rx / (fp->samples_per_subframe*10))&1023;` and
`proc->tti_rx = get_slot_from_timestamp(proc->timestamp_rx, fp);`
This ignores the samples `proc->timestamp_rx % fp->samples_per_frame`
while computing the frame and slot number creating a mis-alignment with the slot boundaries.
We fix this alignment by compensating these samples during the first reception.
semi-manual remove of not used #define commands
As i was upset to see all these #define with no code under, i made a
global pass to remove the obvious cases semi-manual remove of not used
bodies
manual script, then a lot of manual review
grep -IRs "#define" ../openair* ../common/* ../executables/ ../nfapi/ ../radio/ | \
fgrep -v '(' | fgrep -v '//' |awk '{print $2}' | egrep -v "#define *$n"| \
while read n ; do
grep -IRs $n ../openair* ../common/* ../executables/ ../nfapi/ ../radio/ | grep -v "#define *$n" | grep -q $n || echo $n;
done
will give a decent list of #define never used. Then, I think we should
keep lists of # define when it comes from standards, even if the code
doesn't use it right now
NR UE: add support for multiple RF frontends
This MR adds basic support for multiple RF-frontends at the UE.
There are multiple reasons why we might want this:
1. There might be different antennas needed for different bands (e.g. NTN or
TN antennas). These antennas might be connected to different RF-frontends.
In case of Handover, the UE needs to dynamically switch between these
RF-frontends.
2. Each rf-simulator connection carries baseband I/Q samples. To be able to
perform a handover between two cells at different frequencies, there must
be two rf-simulator connections, as the baseband channels should not
interfere and thus cannot simply be added.
3. When we want to support multiple UE simulation within one instance of
nr-uesoftmodem, and allow multiple cells and probably even handover between
these cells, we need either:
1. dedicated RF-frontends for each simulated UE, or
2. dedicated RF-frontends for each connected cell and dynamically assign
simulated UEs accordingly.
This MR implements what is needed for 1., 2. and 3.1.
FHI 7.2 does not have a field for the number of RACH Occasions.
It seems this needs to be manually configured, and M plane has field
num-prach-re to set the number of frequency domain PRACH occasions.
We assumed that PRACH FFT size is equivalent to PxSCH FFT size.
However, the parameter ru_config->fftSize is used for the C-plane Section Type 3
which is dedicated for PRACH and mixed numerology.
Based on the PRACH format, short or long, the PRACH values 256 or 1024
shall be filled.
Co-authored-by: knopp <raymond.knopp@eurecom.fr>
1. Removed function pointers for functions get_samples_per_slot(),
get_samples_slot_timestamp() and get_slot_from_timestamp() as it does
not offer any advantage. The functions are now called directly from
everywhere.
2. Optimized these functions by removing loops where ever possible.
saves about 600MB of memory allocation
Move the definition of PRACH items and the PRACH list to the
defs_nr_commons.h file.
Do not re-write the entire structure in nr_schedule_rx_prach(), as it is
quite large now.
The function rx_nr_prach become autonomous, it doesn't read anymore global variables
So, it can become (later) a threadpool work, that will send a message when it finishes
rx_nr_prach_ru() still use some global variables, but it is executed in sequence, inside the ru main loop, that limits the probability of race conditions
RF emulator and improvements of the timers
RF emulator:
Add an RF library emulating a real device without the need of a real
device. This is thought to enable using phy-test without requiring a
radio device or channel simulation. The library synchronizes on the
real time clock, drops TX and generate noise on RX. Noise generation
can be disabled and the noise level configured.
Timers improvements:
- Fix standard deviation for merged timers
- Add display of ULSCH decoding timers
- Add decoding timer in AAL
RF simulator: Fix concurrency issues during new client connections
- Fix concurrency issues happening when a new client connects, sometimes
leading to a total softmodem deadlock.
- trace in 4G RAR processing to debug ci result
Improvements to the FHI for enabling further use cases
These changes to the FHI were primarily thought to enable the integration of
the intel ACC ( !3344 ) in parallel of the FHI.
I preferred to make a separate MR because I believe this topic is orthogonal
enough to be handled separately and because I wanted to bring even further
improvements.
The improvements that it actually brings are:
- Enable compiling and running xran F release with DPDK 21+
- Enable including a BBDEV device in addition of the ethernet device for the
FHI when performing EAL init, which is necessary for using the intel ACC
with the FHI.
- Fix an issue in usage of pkgconfig in xran E and F release. This enables to
reliably build xran with the version of DPDK requested to pkgconfig while
before this fix xran was always selecting the headers installed in /usr/local.
Get xran stats in the trx_oran_get_stats function
and use trx_oran_get_stats upon stopping and ending RF.
Co-authored-by: Romain Beurdouche <romain.beurdouche@eurecom.fr>
Do not pollute periodic output, and rather print those into
nrL1_stats.log. A number of them are already there anyway, so transfer
the rest. Note: ru->ifdevice.tx_fhaul is omitted, as we don't have any
IF5 split in 5G.
Robert Schmidt