LDPC coding was yet not properly stopped by using free_nrLDPC_coding_interface in gNB and UE.
This was not causing major issue until now. It was especially not causing any issue with T2 LDPC coding using the PF.
But using T2 VFs, if the coding library is not properly stopped then the VF cannot be used anymore unless the admin app is restarted.
So this MR adds the missing free_nrLDPC_coding_interface.
The offset provided for each code block in the HARQ combined input and output buffer shall not be above 512.
A modulus was performed on the offset of the TB in the buffer to avoid this situation.
But the offset of the code block was added afterward so that the total offset was sometimes going above 512.
This commit performs the modulus after adding the code block offset.
Fix calculation of RSSI in pucch_rx.c
Fix two issues with RSSI calculation in PUCCH:
- RSSI was calculated using partial sum instead of average of squared samples.
- There was a missing parentheses pair which causes the RSSI value to underflow.
The proper way to calculate power in dBFS is
let signal_energy = average of squared samples of received signal over resource elements, antennas and symbols under measurement
then:
rssi[dBFS] = -10log10(max_sample^2 / signal_energy),
or (to avoid division):
rssi[dBFS] = -(10log10(max_sample^2) - 10log10(signal_energy))
Delay compensation for PUCCH2
- Implementation of delay compensation for PUCCH2, which minimizes for
exampe logs "reported RSRP index XXX invalid"
- Adding a test to the CI to perform the delay compensation in PUCCH2
- Refactor code to use c16_t data type in PUCCH decoder
Remove spinlock from threadpool task return
The idea to use atomic aligned to cache line for counting finished jobs
is reused, but instead of polling a semaphore was added.
Fix two issues with RSSI calculation in PUCCH:
- RSSI was calculated using partial sum instead of average of squared samples.
- There was a missing parentheses pair which causes the RSSI value to underflow.
The proper way to calculate power in dBFS is
let signal_energy = average of squared samples of received signal over resource
elements, antennas and symbols under measurement
then:
rssi[dBFS] = -10log10(max_sample^2 / signal_energy),
or (to avoid division):
rssi[dBFS] = -(10log10(max_sample^2) - 10log10(signal_energy))
Introduce ITTI queue in RRC-to-MAC direction
resolve ue rcc to mac race conditions by a itti queue, but it doesn't
resolve the problem of exact slot we should apply the new cell
configurtion
Move UL_INFO structure allocation local to a rx slot processing
UL_INFO is allocated a gNB, so require mutex and obscur information
passing function to function. Instead, make a local UL_INFO per slot,
removing the mutex and making the code easier to understand.
Use UL_INFO on the stack, to simplify the code. move in the same struct
the associated rach, pdu, crc, srs arrays that where pointed from
directly in gNB structure Keep in nfapi the existing logic that make
malloc for theses rach, pdu, crc, srs array lists
Pass only relevant fields, where appropriate.
Co-authored-by: Robert Schmidt <robert.schmidt@openairinterface.org>
nrLDPC_coding: Fix naming, comments, superfluous variables and documentation typos in coding library interfaces
This MR is clarifying the interfaces to the LDPC coding libraries. It
aims to improve the readability of the interfaces and compliance of
naming with specification 38.212.
NR UE fix DCI mask size
Previous maximum size was 15 but in practice it could be at least up to
18. Also moved assertion on non-contiguous type0 DLSCH allocation to L1
(to remove blocking point for L2 implementation).
Improvements for PUSCH per symbol processing
- Improved the assert in task_ans.c
- Fixed and issue with PUSCH per-symbol processing that could cause an
issue in case num_pusch_symbols_per_thread is not 1.
nrLDPC_coding: improvements
One improvement in this changeset: Functions nr_interleaving_ldpc,
nr_deinterleaving_ldpc, nr_rate_matching_ldpc and
nr_rate_matching_ldpc_rx that were previously linked with the PHY layer
in the executables are now linked with the LDPC coding implementations
where they are called.
The parent commit cleans up and groups oai_exit in one place,
nr-softmodem-common.h. Therefore, this 5G file is included in the 4G
defs_common.h (at least it's mostly 4G), which is not nice. Instead,
define oai_exit also in 4G softmodem-common.h, and include this in
defs_common.h. Remove the cyclic inclusion of defs_common.h in
softmodem-common.h, and resolve all subsequent errors around unknown
types and extern definition mismatches.
Fix and refactor channel average
- Fixing missing init average variable with zero and refactor the code #86b11ab7
Fixes just the missing avg1=0
- Refactor the code to a common SSE/AVX2 inline function using also horizontal add.
- We use int64_t result from now on.
- We decided to fix length to x12 instead of old x9 openair1/PHY/NR_UE_TRANSPORT/dci_nr.c
//compute average channel_level on each (TX,RX) antenna pair
void nr_pdcch_channel_level(int32_t rx_size,
c16_t dl_ch_estimates_ext[][rx_size],
NR_DL_FRAME_PARMS *frame_parms,
int32_t *avg,
int symbol,
int nb_rb)
{
for (int aarx = 0; aarx < frame_parms->nb_antennas_rx; aarx++) {
//clear average level
simde__m128i avg128P = simde_mm_setzero_si128();
simde__m128i *dl_ch128 = (simde__m128i *)&dl_ch_estimates_ext[aarx][symbol * nb_rb * 12];
for (int rb = 0; rb < (nb_rb * 12) >> 2; rb++) { <-------------- here
avg128P = simde_mm_add_epi32(avg128P, simde_mm_madd_epi16(dl_ch128[rb], dl_ch128[rb]));
}
DevAssert(nb_rb);
avg[aarx] = 0;
for (int i = 0; i < 4; i++)
avg[aarx] += ((int32_t *)&avg128P)[i] / (nb_rb * 12); <-------------- and here
LOG_DDD("Channel level : %d\n",avg[aarx]);
}
}
Optimize PHY_ofdm_mod CYCLIC_PREFIX in case of incidentally aligned pointers
It seems that the cyclic prefix is in most cases a multiple of 512 samples.
This means that in most cases the idft output pointer is already aligned and
there is no need to perform an extra memcpy. This saves the memcpy time in
most cyclic prefix insertion cases.
Alignment of temporary IDFT buffer was changed to 64 bytes. This is in preparation
for possible use of different IDFT implementation which could use AVX-512, requiring
64-byte alignment.
Add support for O1 in O-DU via telnet
This change set adds a simple telnet interface to nr-softmodem. Together
with oai/o1-adapter>, this implements a part of the O1 interface, for
the DU only. Currently supported uses cases:
- some stats are send to an SMO (such as bandwidth, PLMN, frequency, ...)
- re-configuration of bandwidth, frequency
- stop/start of the softmodem, while keeping the CU and L2 running
- the o1-adapter implements two alarms, load overload and base station
offline, using this interface.
It is possible to use the telnet interface by itself (i.e., "o1" without
the o1-adapter). To do this, compile with telnet support (./build_oai
--build-lib telnetsrv) and start the nr-softmodem with O1 module
(./nr-softmodem --telnetsrv --telnetsrv.shrmod o1). You can then do the
following:
- see some statistics as exposed to o1-adapter, in JSON: echo o1 stats | nc 127.0.0.1 9090 && echo
- stop the L1: echo o1 stop_modem | nc 127.0.0.1 9090 && echo
- reconfigure bandwidth: e.g., echo o1 bwconfig 20 | nc 127.0.0.1 9090 && echo (also supported: 40, 60, 100)
- start the L1: echo o1 start_modem | nc 127.0.0.1 9090 && echo
Note that the reconfiguration works with split-8 radios. Notably, it
does not work yet out-of-the-box with 7.2 radios, because they have to
be manually reconfigured on bandwith/frequency switch. The planned
M-plane should allow such use case, though.
To help with the above, this branch also includes fixes (for more
information, refer to the corresponding commits):
- fixes for stopping the L1, notably stop threads in right order, stop
thread pool of RU
- collect some general MAC metrics, fix some bugs in MAC
- fix problems in F1AP gNB-DU configuration update message, update test
- fix some problems in RRC
Need to keep track of number of RUs, as the RU initialization increments
the number of RUs. Therefore, subsequent initializations would fail if
we don't decrement first. There is no better place (or I did not find
it) to decrement the number of RUs than in nr_phy_free_RU(). For this
reason, we also have to manually set the number of RUs in nr_prachsim to
1, otherwise the assert will trigger.
The existing code prevents double initialization if e.g., both gNB&UE
call these functions (like in a simulator). However, in the case of a
double-initialization such as stopping and re-starting the L1, the
memory will be freed, but not freed again. Basically, this works:
generate()
generate() # not initialized again
but this leads to problems:
generate()
free()
generate() # not initialized again, but should be!
Reimplement the check based on the data to be initialized, such that an
intermediate free() will be handled properly.
New LDPC coding library interface for decoding and encoding complete slots in one call to the library
Previous attempts to integrate LDPC decoding relying on offloading show
the limitation of the original code segment coding interface for the
library implementing LDPC coding. In order to perform the offload and
therefore the decoding in an optimal fashion, it is relevant to provide
the implementation with the broader amount of data possible per call,
which is a slot. A previous MR related to T2 offload managed to offer
an interface for decoding transport blocks by modifying only
nr_ulsch_decoding.c. But this may not be sufficient for performing an
efficient decoding in any situation. Slots could be shared between
multiple transport blocks in case multiple UEs are connected to the RAN,
which makes the transport block size shrink and therefore degrades the
efficiency of the offloading.
This MR offers a broader interface with a gNB decoding entry point in
phy_procedures_nr_gNB.c. The file nr_ulsch_decoding.c now lets the
decoding library implement deinterleaving, rate-unmatching and decoding
for the slot. In gNB encoding and UE decoding and encoding as well,
tasks are partitioned in a similar fashion.
As it allows to feed the implementation with the broadest amount of data
possible, it allows to fit any coding solution in a library. This will
avoid further modification to OAI source code and addition of options to
select an implementation when integrating new decoding solutions. An
implementation of this interface will therefore be offered for every
existing decoding solution in OAI and solutions added in the future will
be provided as independent module code without any modification to the
core of OAI code. The way to choose the decoding solution and to
configure it was also unified using configmodule. The library can be
chosen through the option --loader.ldpc.shlibversion. The slot coding
solutions shipped with this MR can be configured through configmodule
(e.g., T2 address and isolated cores).
This MR includes three coding implementations:
- A wrapper around segment decoding libraries for test purpose: libldpc.so
- A one shot slot coding and encoding with the T2 board: libldpc_t2.so
- A decoder on FPGA using the XDMA driver: libldpc_xdma.so
Improvements brought by this MR:
- Easy integration of a wider variety of LDPC coding solution at gNB and UE
- Easy selection of the LDPC coding solution (option --ldpc-offload-enable is kept for now but it can be ultimately removed)
- T2:
* More efficient when many UEs are connected
* Decoding and encoding in nr-uesoftmodem
Romain Beurdouche