Till this commit, the UE gets the position of SSB in frequency from
command line and does the syncronization by locating the SSB in time. It
does this by generating a PSS time signal during initialization with the
SSB offset given via command line. Then PSS detection is done by
correlation.
In this commit, the UE computes a list of GSCN in the current NR band
that falls within the current bandwidth for the set center frequency.
For each GSCN in the list, the UE starts a thread and performs the
following:
1. Generate PSS time signal with SSB offset for current GSCN.
2. Detect PSS, SSS and decode PBCH (this step remains the same).
After all threads finishes, the results are collected.
For now, only the first detected PBCH is used to proceed further. So
this PBCH is indicated to MAC and UE exits initial sync.
Future work: The cell search can be standalone feature where the UE
could scan for SSB in the entire NR band. This would require changing
radio's frequency on the fly as the UE's bandwidth would not cover an
entire NR band. The cell detection can futher be imporved by looking
for SIB1 for each decoded PBCH.
Add ulsch decoding measurements, which are reported by nr_ulsim. Start ulsch_decoding_stats measurement before
nr_ulsch_decoding is called and stop it after collection of all decoder tasks from Tpool. In the context of nr_ulsim,
ULSCH_id is allways == 0, testing is performed per one TB, therefore measurement is started and stopped only once per trial.
Reported ulsch decoding statistics show the mean ulsch decoding time over x trials (specified by -n command line option of nr_ulsim).
This measurement does not provide valid information in case of nr-softmodem, when the loop is done over multiple ULSCH IDs -
start of the measurement is done multiple times and stops only once in this case.
For unitary physical simulators, ULSCH processing loop is executed only once
- the max number of PUSCH is set to 1. This ensures exactly one start and stop
of the ULSCH decoding time measurement per processed TB.
Note: ulsch decoding statistics reports average time of segmentation, rate matching, interleaving and decoding of the TB
- deleted: ../../../executables/rfsim.c
- removed unused command line options to set SINR and SNR
- removed unused functions to get SINR and SNR
- removed unused RFSIM struct members
PUSCH decoding is started multiple times in nr_ulsch_procedures() for
each ULSCH segment, and stopped once inside
phy_procedures_gNB_uespec_RX(). Not only is it not clear if that works
with the API, it also might measure more than just PUSCH decoding.
Remove the PUSCH decoding, it is misleading. Check L1 RX processing
instead.
This commit introduces a separate thread (l1_tx_thread) that processes
gNB DL/TX slots. It receives a message from the ru_thread when a new
slot started, and starts processing.
The DL part of the scheduler is run in the l1_tx_thread. Therefore,
only call UL indication (for scheduler) in UL slots. The UL indication
previously triggered the DL scheduler -- hence, it had to be called in
every slot. Now, since the DL scheduler is moved into the DL thread, we
don't have to call the scheduler in every slot anymore.
The reorder thread is removed, as reordering with this scheme is not
necessary anymore.
The main advantage of this version is that the TX can be scheduled
earlier (sl_ahead). Further, there can no longer be race conditions in
the TX path, since the scheduler/L2, TX L1 processing and the RU tx
function are all execute in the same thread (L1_tX_thread).
Also, the scheduler prepares PRACH/PUSCH/PUCCH FAPI PDUs. As of this
commit, the scheduler runs in the TX processing chain, whereas these
PDUs are destined for RX processing. Thus, too avoid data races,
instead of triggering the RX processing at the same time as TX
processing in the RU thread, this commit changes the code to trigger RX
processing after the scheduler has been run in TX processing to avoid
data races.
Finally, we synchronize RU and L1 threads. This is important for
rfsimulator, since unlike most radios, rfsimulator can run slower or
faster, depending on I/O and CPU (it does not have a stable "tick").
Co-authored-by: kiran <saikiran@iitj.ac.in>
Sakthivel Velumani