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.
1.Create new funtion nr_symbol_fep() to do OFDM demod of one symbol on
all antennas. This is called by nr_slot_fep() for now. In the
upcoming MR, this function will be called directly after reading
each OFDM symbol from the radio.
2.Removed redundant memory alignment. DFT function performs memory
alignment if the input memory is not aligned.
Since there is no UCI on PUSCH implementation in gNB, it is good to test
UE's implementation with matlab.
This commit allows to test with matlab in two ways:
1. generate OFDM waveform from ulsim and decode it in matlab using
uci_on_pusch_decode.m
2. generate codeword in matlab using uci_on_pusch_encode.m read it in
ulsim and compare the bits. ulsim option -o is used
After the UE is configured with pdcch-Config, it continues to monitor
fallback search spaces in pdcch-ConfigCommon for DCI with C-RNTI.
The rational is that after sending RRC Setup the network won't know if
the UE has received and successfully applied it. Hence the network would
still continue to use the fallback DCI till it receives RRC setup
complete.
Changed the search structure to have periodic resoruce id in the outer
loop and configured resource set as inner loop to prevent configuring
resource that is not needed.
Use const for input pointers.
DC subcarrier has a significantly higher energy compared to other CSI IM
resource elements. This causes the average interference + noise
estimation to be higher than CSI-RS signal power making the CQI 0. With
a third-party gnb that schedules PDSCH based on CQI, the UE never
receives DL DCI once it starts sending CSI reports.
The LLR threshold buffers hold only for one symbol but the LLRs are
computed for all symbols together. So only the threshold of last symbol
was used for computing LLR for all other symbols.
This commit calls nr_dlsch_llr for each symbol togther with rest of
nr_rx_pdsch() and calls nr_dlsch_layer_demapping at the last symbol.
Fixes issue 948.
TS 38.213 4.1 says coreset 0 is present only if kssb < 24 for FR1 and <
12 for FR2. This commit sets get_sib1 flag based on kssb.
Also, setting of mac state is taken out of function nr_ue_decode_mib().
Recently f buffer was changed to hold packed bits and the correspoinding
change in dlsim was not done so the number of error bits before decoding
was incorrectly reported. This commit fixes it.
After capturing the FH packets, we observed that the RU supports the MTU value for jumbo frames.
Therefore, no fragmentation needed on DL.
Co-authored-by: Teodora Vladic <teodora.vladic@openairinterface.org>
The functions nr_generate_csi_rs() and nr_ue_generate_csi_rs() are
identical. This commit removes nr_ue_generate_csi_rs() and moves
nr_generate_csi_rs() to nr_phy_common_csirs.c so both gNB and UE can use
the same function.
The UE stores PDCCH search spaces from the network in NR_BWP_PDCCH_t
struct within NR_UE_MAC_INST_t. After storing, the pointers otherSI_SS,
ra_SS and paging_SS are updated to point to the stored SS. Multiple
pointers could point to the same stored SS struct depending on
configuration. Then when the UE wants to release the SS, the pointers
are used to free the stored SS using ASN_STRUCT_RESET(). If multiple
pointers point to the same SS, calling ASN_STRUCT_RESET() on all
pointers would lead to double free. So one needs to check for dangling
pointer before freeing.
Instead of using pointers and assigning them during configuration, we
use SS id for otherSI_SS, ra_SS and paging_SS to retrieve the pointers
whenever needed. When the UE wants to release the SS, we make them -1
indicating an invalid SS id.
nr_dlsim allocates memory on every SNR iteration without freeing it.
This can lead to memory exhaustion. Fix this by allocating only once
and reuse memory. Also, free it before exit.
Use memcpy in nr_prach.c to fill txdata buffer.
Remove global tables related to PRACH generation.
Add new function to compute modulo multiplicative inverse and use it
directly to get inverse instead of LUT.
Removed nr_ru table and compute the values in-place.
In UE, added new flag root_seq_computed in nrUE_config to only compute
the sequence once after new nrUE_config is received.
Long PRACH extends beyond a slot. Changes necessary to mark future slots
that may contain prach in ru, phy and mac functions.
In RU, the PRACH IDFT is done only after receiving last slot and marks
for L1 to start processing. The L1 processes at the last prach slot and
reports to MAC with the first slot index.
In MAC scheduler, the VRB for future slots are also marked as used.
PRACH scheduler is called in advance one frame minus num prach slots.
function returns mu of UL BWP if msg1-SubcarrierSpacing absent instead
of asserting. The mu retured by this function is used to compute the
slot number of PRACH. In case of long format, the slot number is as per
UL mu.
B200 with high clock drift will go out of sync within 280ms which was
the default duration to sync in with iqrecorder. Now this value can be
specified via cmd line so the user can change it according to needs.
Move handling of sync request from MAC from UE_dl_preprocessing(). This
will process the sync request before receiving the samples of current
slot from radio so we don't 'lose' the slot.
When more than one sdu with equal priority is present, there could be
buffer left after serving the lcids and also not enough for equaly
serving all lcids. This commit checks for this condition. Before this
fix the ue would send malformed mac pdus when serving multiple lcids.
Mapping of data REs in DMRS symbol depends only on number of CDM group
no data. So the special case function that depended on delta is removed
and a single function is used.
There was concern that someone in the future might call the function
with the wrong inputs. So, based on the discussion on the MR below
https://gitlab.eurecom.fr/oai/openairinterface5g/-/merge_requests/2916#note_132506
the SIMD for multiplying DMRS vector with amplitude is removed and is
now done with plain C (no SIMD).
The execution time for the function dmrs_amp_mult() in this commit is
10x higher that the previous commit.
It is better to write to memory that are grouped together to reduce
probability of cache miss. This simple change improved the function's
execution speed by 70%.
Removed the unnecessary memset for the buffer.
A particular GCC version (v13?) used by CI machines potentially has a
bug that issues a mismatch bound warning on function array arguments.
This commit should prevent it from happening.
There is already a command line option called 'ue-scan-carrier' which
seemed to blindly look for SSB by changing the center frequency by
+/-100Hz if the previous attempt failed. This is probably copied from
LTE and is not suitable for NR. This commit uses this option to either
1. Perform initial sync on one GSCN if the SSB position if known
2. Or scan the all GSCN (if the SSB postion is unknown)
Also, the following is done for re-synchronization
1. Scan all GSCN when UE comes back from IDLE state
2. Scan one GSCN when UE does re-estabishment
Removed dependency of lte-softmodem.h in nr-softmodem.c.
CONFIG_HLP_UESCAN is declared also in lte-softmodem.h.
Changed Info to Debug because the logs are too much if large number of
GSCN scans run concurrently. Print PSS correlation peak and average
power of detected cells.
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.
Sakthivel Velumani