Realtime and near-realtime RFSimulator alternative without channel modelling.
The purpose of this library is to allow realtime simulation of gNB and nrUE.
The library is loaded using --device.name shm_radio. The server side (gNB) should also
configure --shm_radio.role server and --shm_radio.timescale <timescale> according to requirements.
Limitations:
- Only 1UE-to-1gNB connection supported
Future work:
- Channel modelling
- Telnet API
- Histogram of the TX time budget
Change to bool for clarity. The log message would sometimes only show up
at the end, which is misleading; use the logging module, which
harmonizes log statements and should make this appear immediately.
We still do not handle RUs with MTUs of 1500 properly in F release;
therefore, for the close future, we cannot remove support for E release.
Also, it "promises" this for January, which is in the past already.
Update to keep the warning logical.
Use `rfsimu_channel_ue1`, `rfsimu_channel_ue2`, etc. if you want to
use different channel models for each client. The client connection
order determines its channel model name.
Enable/disable workaround based on a new option "hanging-workaround".
This addresses an issue where the workaround will trigger even if there
is no risk of a permanent lockup of the system.
Added new command line option to channelmod: noise_power_dBFS. This options
allows the user to configure noise power in dBFS added instead of the per-channel
value.
This makes it so noise is not accumulated per channel reaching higher than expected
values.
The dBFS unit allows easy configuration. The gNB by default uses -36 dBFS setting.
To reach 3dB SNR one should set the noise_power_dBFS value to -39.
To configure using command line use --channelmod.noise_power_dBFS -50. Using this
setting the gNB and nrUE connect without issue.
FHI72: remove polling, fix memory leak
- FHI72 used polling to track the next slot. This is not necessary, a
simple queue does the job and allows to save one core that was
previously at 100%
- Remove a workaround to avoid a memory leak (fixes#812); allows to
also run RFsim/USRP/otehr radios when compiling for FHI72
fix NTN LEO scenarios
- gNB: add support for NTN parameter ta-CommonDrift-r17
- NR UE: fix application of NTN TA information
- NR UE: add command line parameter ntn-initial-time-drift to compensate
time drift during initial sync
- NR UE: fix writeTimestamp inconsistencies
- NR UE: add MAC state UE_RECEIVING_SIB ensuring to start RA only after
successfully receiving SIBs
- rfsimulator: update earth radius for LEO simulation to match UE
position in ue.conf file
- update conf files for NTN LEO scenario
- update description how to run NTN scenarios in RUNMODEM.md
- fix: ta-Common is a round-trip-time, not a one-way delay
- NR UE: simplify calculation of next_tx_slot_and_frame by moving up
assignment of duration_rx_to_tx
- cellbarredNTN indicates notbarred in SIB1 if NTN access is available
- Removed b66 NTN and enabled B254 NTN conf file in CI
- NR UE: RRC layer now explicitly tells MAC layer when the RA procedure
can be started
- move NTN LEO config to band 254 and update doc/RUNMODEM.md
Closes#901
first_rx_set is polling-specific: it makes the polling loop wait to only
check the frame/slot counter once we set it for the first time. However,
that is equivalent to checking the frame/slot directly, which will also
be 0 in the beginning.
first_read_set seems to have the function of making frame/slot time
advance only if we started to read the samples in
xran_fh_rx_read_slot(). I interpret that as "only advance the time if
the gNB is reading from xran", which does not make sense to me, because
xran advances the time anyway. Also, polling would not notice, and
no-polling would simply warn about double messages. So the outcome is
likely the same, whether first_read_set is set or not.
I checked in multiple CI runs; it happens that first_read_set is always
set already when oai_xran_fh_rx_callback() is called anyway.
xran_fh_rx_read_slot() uses polling (a loop over cnt++) to wait for the
next frame/slot. The reasons I have been told is "it does not work
differently", or "there are real-time problems". None of those seem to
be true; by default disable polling, and use the queue instead.
It is possible to enable polling with the cmake option
OAI_FHI72_USE_POLLING=ON. Documentation has been updated to inform about
this change.
The queue L1_rx_out was in place to keep RX/TX processing relatively
"close" to each other (in terms of time, since in RFsim, they might
advance faster than realtime; see also parent commit). This lead to a
memory leak in radios that do not use ru->feprx (no front-end processing
for RX, e.g., PRACH), as the code to read the L1_rx_out messages was
inside a block of if (ru->feprx). Move it out so that the queue is
always read and messages are freed to eliminate the memory leak, and
remove the workaround for FHI72 to avoid this memory leak.
This also allows to run RFsim when compiling FHI72, which was not
possible before this commit.
Closes: #812
Deadlock avoidance in rfsimulator
This change introduces a countermeasure for deadlock in rfsimulator. The
deadlock happens when all entities are waiting for new data to come in,
and happens with 2+ clients, when a new client connects. I think this
issue is due to ordering of fullwrite calls, resulting in out-of-order
delivery of packets and eventually trashing the packets on the receiving
side. The out-of-order delivery warnings are printed just before the
system deadlocks but I have not found a better solution so far. The
workaround makes the server never lock up permanently by ignoring the
client failure to write on time after 10 tries.
This was tested locally for both UE as server and gNB as server and
works correctly, causing the deadlock to clear and the added log to be
printed several times when the deadlock is detected, after which the
system goes back to normal.
I have some gdb output of the executables during deadlock:
UE:
$7 = {conn_sock = 98, lastReceivedTS = 3226163740, headerMode = true, trashingPacket = false, th = {size = 13184, nbAnt = 1, timestamp = 3226150556, option_value = 0, option_flag = 0}, transferPtr = 0x7f6a500018a8 "\200\063", remainToTransfer = 24,
circularBufEnd = 0x7f6a503b3ac0 "", circularBuf = 0x7f6a501f1ac0, channel_model = 0x0}
(gdb) p t->buf[5]
$8 = {conn_sock = 97, lastReceivedTS = 0, headerMode = true, trashingPacket = false, th = {size = 0, nbAnt = 0, timestamp = 0, option_value = 0, option_flag = 0}, transferPtr = 0x7f6a50001900 "", remainToTransfer = 24, circularBufEnd = 0x7f6a50575ad0 "",
circularBuf = 0x7f6a503b3ad0, channel_model = 0x0}
nextRxTimestamp 3225937740
nsamps = 30720
gNB 1:
(gdb) p t->buf[0]
$4 = {conn_sock = 95, lastReceivedTS = 3226026876, headerMode = true, trashingPacket = false, th = {size = 1, nbAnt = 1, timestamp = 3226026875, option_value = 0, option_flag = 0},
transferPtr = 0x7f8dfc003ab8 "\001", remainToTransfer = 24, circularBufEnd = 0x7f8e1c3ff010 "", circularBuf = 0x7f8e1c23d010, channel_model = 0x0}
nextRxTimestamp 3225996956
gNB 2:
lastReceivedTS = 3226026875
$2 = {conn_sock = 95, lastReceivedTS = 3226026875, headerMode = true, trashingPacket = false, th = {size = 1, nbAnt = 1, timestamp = 3226026875, option_value = 0, option_flag = 0},
transferPtr = 0x744898003ab8 "\001", remainToTransfer = 24, circularBufEnd = 0x7448bc2e7010 "", circularBuf = 0x7448bc125010, channel_model = 0x0}
nextRxTimestamp 3226026875
As you can see all executables are in have_to_wait state.
FHI72: fix for a distributed antenna array for xran F release
in the Rx callback I reset the number of section descriptions/number of
fragments to 0, but for each antenna up to max number of antennas per
RU, instead of up to max number of distributed antenna array
- in the Rx callback I reset the number of section descriptions/number of fragments to 0,
but for each antenna up to max number of antennas per RU, instead of up to max number of a distributed antenna array
FHI72: FDD support
- harmonize DL/UL PRB mapping in one get_xran_prb_map() function with support
of mixed slot and duplex mode
- do not assume TDD by default
Remove most of m64 type usage
MMX instructions were first SIMD version, the registers management is complex
(_mm_empty()) so, it is better to remove it now and use more recent instructions
anyway, gcc/clang should replace it automatically as long as we enable sse2,
that should always be the case but for code understanding and for ARM porting
for example, it is better to explicitly remove it
- extend get_xran_prb_map() function to handle mixed slot
- properly fill PRB configuration based on DL/UL direction and duplex mode
- do not implicitly assume TDD
- the parameters used in DL/UL are exactly the same, except the direction and the number of PRBs;
therefore, passing the direction seems convenient for visibility purposes and reduces the code.
Note: Number of PRBs we store in fh_config for both DL/UL is num_rb_dl of openair0_config struct.
At the end, it is actually the same info.
fhi_72: allow to provide dpdk_iova_mode to xran
- Introduce a gNB configuration option that enables users to select the
desired IOVA mode for DPDK ("PA" or "VA") with dpdk_iova_mode
parameters in fhi_72 configuration section. If not set, the default
remains PA mode to ensure backward compatibility with existing
configurations. Detailed information about IOVA modes, including their
advantages and disadvantages, can be found in the DPDK documentation:
Memory in DPDK Part 2: Deep Dive into IOVA
- Using IOVA VA mode allows DPDK to run without requiring SYS_ADMIN
capability for the docker container.
- Switch to IOVA VA mode in the FHI7.2 pipeline and reduce the required
capabilities for the docker container.
In DPDK, IO Virtual Addresses (IOVA) refers to the memory addressing
scheme used for IO operations. The two IOVA modes supported by DPDK are:
- IOVA as Physical Address (PA): IO memory addresses correspond directly
to physical addresses, no address translation required.
- IOVA as Virtual Address (VA): IO memory addresses align with user-space
virtual addresses, requiring IOMMU to remap physical memory.
Previously, this was hardcoded to 0, to use IOVA as PA mode, with xRAN's
DPDK EAL initialization using the "--iova-mode=pa" flag.
This commit introduces a gNB configuration option to allow users to select
the desired IOVA mode. The default remains PA mode to
ensure backward compatibility.
Using IOVA VA mode allows DPDK to run without requiring SYS_ADMIN
capability in the docker container.
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.
Cmd line option for sync in frames for iqrecorder
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.
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
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.
