This commit adds a performance benchmark for the end-to-end channel simulation pipeline, named `test_channel_simulation`. Its methodology is as follows:
- It systematically iterates through a matrix of test cases, varying
MIMO configuration (Tx/Rx antennas), signal length, and channel
length.
- For each case, it runs both the full CPU pipeline (`multipath_channel_float`
followed by `add_noise_float`) and the single `run_channel_pipeline_cuda`
function.
- It measures the average execution time for both implementations over
many trials and calculates the resulting speedup.
This provides a performance characterization of the GPU pipeline across different workloads and directly compares it to the CPU baseline.
This commit adds a new standalone benchmark, `test_noise`, to measure
and compare the performance of the CPU and CUDA implementations of noise
generation.
The benchmark's methodology is as follows:
- It iterates through various configurations, including different
numbers of receive antennas and signal lengths.
- For each configuration, it runs both the CPU (`add_noise_float`)
and CUDA (`add_noise_cuda`) functions multiple times to get a stable
average execution time.
- It prints a formatted table comparing the CPU and GPU latencies and
calculates the resulting speedup.
This commit adds a new standalone unit test, `test_multipath`, to
validate the CUDA implementation of the multipath channel.
The test performs the following steps:
- Generates a random input signal and channel model.
- Runs the CPU version (`multipath_channel_float`) to get a baseline result.
- Runs the CUDA version (`multipath_channel_cuda`) with the same inputs.
- Compares the two outputs by calculating the Mean Squared Error (MSE)
and ensures it is below a small tolerance.
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.
This feature shall allow in future to simulate an arbitratry number of UEs connected to an other arbitrary number of cells.
Therefore each RF-frontend (also called RU) needs to be configured for one specific cell.
In case of handover of a UE from one cell to another cell, it needs to switch RUs accordingly (TODO).
There has to be a 1-to-1 mapping between RUs and cells.
Each UE will be assigned to one of the defined cells.
Initially all UEs are assigned to cell 0.
UE support to send CSI report on PUSCH
Earlier work on UCI on PUSCH implemented only ACK/NACK. This MR extends that
to send CSI report too.
This branch is verified with MATLAB implementation for multiplexing CSI part 1
and part 2 on PUSCH. It is also verified with srsRAN gNB which successfully
decodes CSI part 1 on PUSCH.
Fix RSRP overflow
If UE L1 measure an RSRP = 0 it would report to L2 and RSRP value of -INT_MAX
dBm causing overflow in the qsort to determine the best RSRPs
The global variable rx_gain_off was always 0.0, as it was not even modified by the NR UE command line parameter --ue-rxgain-off.
That command line parameter modified only a parameter in the struct nrUE_params_t, which was not used at all and is removed in this commit, too.
Also, the global variable rx_gain_off was just added to rx_total_gain_dB and subtracted from it again in nr_rf_card_config_gain().
So we simplify that function slightly, too.
Cleanup nr_slot_fep_ul
Rename nr_slot_fep_ul to nr_symbol_fep_ul to relfect its function
Simplify logic so that the function does not require RU context and
the implementation is not dependent on the implementation of RU buffer
management.
This makes the function easier to understand and moves the responsibility
to set the correct buffer offset on the caller.
Rename nr_slot_fep_ul to nr_symbol_fep_ul to relfect its function
Simplify logic so that the function does not require RU context and
the implementation is not dependent on the implementation of RU buffer management.
This makes the function easier to understand and moves the responsibility
to set the correct buffer offset on the caller.
NR UE: add neighboring cell measurements and measurement report of event A3
This is a rework of MR !2385 (closed), the goal is to add neighboring cell
measurements and measurement report of event A3 for NR UE.
This MR was tested with:
- 3rd-party gNB
- 2 OAI-gNB-DUs
The neighboring cell measurements and measurement report of event A3 for OAI-UE
are working as expected.
Introduce SRS physical simulator and improvements
This MR consists of two parts:
- Introduces SRS physical simulator to test different configurations of
SRS
- Improvements in the SRS channel estimation (Addressing the comments
from old, unfinished MR !2875)
- rewrite nr_srs_channel_estimation() to loop over rx antennas and
antenna ports to be able to parallelize
- Improvements in timing_advance_offset and timing_advance_offset_nsec
computation
- Introduce SRS multi-symbol channel estimation
- The channel impulse response is estimated from the averaged
channel frequency response over multiple symbols
- The channel frequency estimates are left as they are to be able to
estimate doppler in the future
- Simplify SRS channel estimation to handle memory alignment in the
case of different SRS configurations (eg: comboffset)
To use multiple symbols when running gNB, the following parameters needs
to be edited in the function get_srs_resource()
- srs_res->resourceMapping.startPosition with a range from {0,1,..,5}
corresponds to the start symbol {13, 12, .. 8} with in a slot
- srs_res->resourceMapping.nrofSymbols indicates the number of symbols
{n1, n2, and n4}
Make sure the that start symbol + number of symbols is < 14
The timing results for SRS in develop and srs_phy_simulator are as follows:
Command used: sudo ./nr_ulsim -n1000 -s50 -S50 -R273 -W2 -y2 -z2 -E 1 -P
develop
|__ RX SRS time 124.94 us (1000 trials) (124.94 total [ms])
|__ Generate SRS sequence time 0.05 us (1000 trials) ( 0.05 total [ms])
|__ Get SRS signal time 19.41 us (1000 trials) ( 19.41 total [ms])
|__ SRS channel estimation time 89.11 us (1000 trials) ( 89.11 total [ms])
|__ SRS timing advance estimation time 13.10 us (1000 trials) ( 13.10 total [ms])
|__ SRS report TLV build time 2.80 us (1000 trials) ( 2.80 total [ms])
|__ SRS beam report build time 0.00 us ( 0 trials)
|__ SRS IQ matrix build time 2.73 us (1000 trials)
srs_phy_simulator
|__ RX SRS time 211.93 us (1000 trials) (211.93 total [ms])
|__ Generate SRS sequence time 0.04 us (1000 trials) ( 0.04 total [ms])
|__ Get SRS signal time 19.55 us (1000 trials) ( 19.55 total [ms])
|__ SRS channel estimation time 152.05 us (1000 trials) (152.05 total [ms])
|__ SRS timing advance estimation time 36.67 us (1000 trials) ( 36.67 total [ms])
|__ SRS report TLV build time 2.96 us (1000 trials) ( 2.96 total [ms])
|__ SRS beam report build time 0.00 us ( 0 trials)
|__ SRS IQ matrix build time 2.88 us (1000 trials)
Note that in srs_phy_simulator, to compute timing offset ns, an
oversampling factor of 2 is performed. Also, for peak detection, we
average the channel estimates for every port.
fix array lenght errors, k variable wrapping threshold. Make the code smaller and more efficient
generate_nr_prach() has several errors coming from replace int16_t by
c16_t, and also older error in k wrapping at the end of the symbol
the code is also ridiculously complex, wasting memory and cpu time in
intermediate useless buffers and headache usage of memmove()
- We use the same function at gNB and UE.
- We always use nb_antennas_tx to check the max possible number of ports (which is wrong).
- At gNB, we should use nb_antennas_rx and at the UE, we should use nb_antennas_tx.
The memory alignment is required to use c16multaddVectRealComplex
in SRS channel interpolation. With a change in SRS comb_offset, the
existing algorithm was giving segmentation fault.
The existing srs channel estimation required memory alignment at two
stages. 1. When k = 0 (the first srs subcarrier), 2. When subcarrier <
K_TC (wrapped around after ofdm_symbol_size). Thus two memory alignments
are required leading to complications.
The srs channel estimation is now simplified to do it linearly instead of
wrapping around. This simplified the memory alignment required only when
k = 0.
- Introduce signal energy and noise variance functions
- Combine rotation and OFDM modulation RX as a function
- Harmonize the use of number of antennas across the code
- Rename nr_ue_pusch_common_procedures() to nr_tx_rotation_and_ofdm_mod() to decribe the functionality better
Nika Ghaderi