Update the comparator() to properly sort UEs based on their coefficient
by appliey a consistent logic of -1/0/1 (see man qsort) for
smaller/equal/larger. The previous logic was only sorting based on 0/1
(equal/larger), which would result in some UEs with a high coefficient
not necessarily advancing to the start of the list, which could reduce
the likelihood of them being scheduled when they actually should (in
other words, this should improve fairness).
See also: 62e4025bc8 ("Integrate inactivity scheduling into main
allocation loop")
Taps client for vrtsim
The MR allows vrtsim to connect to the Raytracing Channel Emulator (CE later).
https://gitlab.eurecom.fr/oai/raytracing-channel-emulator
Additional Ubuntu packages required:
- libnanomsg-dev
- flatbuffers-compiler
- libflatbuffers-dev
Everything was tested on the same host. Follow the steps below to
successfully replicate:
1. Build nr-softmodem dependencies
2. Build nr-softmodem for (gNB, nrUE) with OAI_VRTSIM_TAPS_CLIENTset to ON.
3. Start the core network (Optional) follow this tutorial
4. Start the gNB
sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band78.fr1.106PRB.usrpb210.conf --gNBs.[0].min_rxtxtime 6 --device.name vrtsim --vrtsim.role server --vrtsim.timescale 0.5 --vrtsim.taps-socket ipc:///tmp/ru_socket_0
5. Start the nrUE
sudo ./nr-uesoftmodem -C 3619200000 -r 106 --numerology 1 --ssb 516 --band 78 --device.name vrtsim --vrtsim.taps-socket ipc:///tmp/ue_socket_0
6. Start the CE Server, once the UE and gNB are running properly, so the
server can connect to IPC sockets
7. Start CE client; the binaries can be downloaded from a pipeline run
or from this link
8. Move the UE in the CE client to generate a new taps array and
populate the taps in softmodems
Align add_boolean_option as per CMake documentation use only ON/OFF for uniformity
The add_boolean_option of CMake is not uniform everywhere. We were using
either True/False or ON/OFF. It is better to be uniform to avoid
confusion.
As an example, see here CMake documentation for an example:
https://cmake.org/cmake/help/latest/module/CMakeDependentOption.html#example-basic-usage
There are also some minor spelling corrections.
some work for better interoperability with srsRAN DU
Just add the minimum to get some user plane traffic going on.
When doing user plane traffic, in the CU logs we have a lot of:
[GTPU] NR-RAN container type: 1 not supported
That will be fixed in another MR, not here.
Interoperability testing with srsRAN DU shows than when receiving
RRCReconfigurationCompleteIndicator in a UEContextModificationRequest
the DU replies in the UEContextModificationResponse with an empty
CellGroupConfig.
This CellGroupConfig is encoded as 2 zero bytes. Let's ignore this
message when we receive it, don't forward it to the UE in a
RRC Reconfiguration, as it should per standard (38.473 8.3.4.2):
If the CellGroupConfig IE is included in the DU to CU RRC Information
IE contained in the UE CONTEXT MODIFICATION RESPONSE message, the
gNB-CU shall perform RRC Reconfiguration as described in TS 38.331 [8].
The CellGroupConfig IE shall transparently be signaled to the UE as
specified in TS 38.331 [8].
To be removed/reworked in the future if the interoperability
situation improves.
This is in 3GPP TS 38.425.
Because it was not done, there was a problem of interoperability
between openair CU and srsran DU. No DL traffic was reaching the UE.
A new GTPU API function is introduced: gtpv1uSendDirectWithNRUSeqNum().
It is only used in the gNB CU, in PDCP. So it was decided to not add a
new parameter to gtpv1uSendDirect() but instead add a new API function.
Replace the unwieldy unix socket implementation of peer information
exchange with an authorative connection descriptor file that
informs the client of the connection method an number of antennas
on the server.
This allows the server to run without the client and allows the
client to reconnect as long as the server is running, as many times
as needed.
Move the channel state management outside the channel implementation.
This simplifies the channel implementation but forces users of the
channel to manage it's state manually.
Add handling for error states in vrtsim which allows to close the
softmodems with CTRL+C without hanging, improving user experience
- Client detection of stale timer.
- Abort state for client and server
Added a libary that can connect to a channel emulator and provide taps
as they are generated.
- Enable connection from vrtsim to channel emulation server
- Depends on flatbuffers definition file from raytracing-channel-emulator
- Depends on libanomsg-dev and flatbuffers-compiler (Ubuntu) or equivalent
- Added a compile time option ENABLE_TAPS_CLIENT to prevent other users
from being affected by additional dependencies
separate computation of size and value for DCI precoding information
This removes stuff that is only relevant for the gNB from the common
functions and moves it to the gNB scheduler functions (related to UL
precoding). In principle no functional change.
2 functions with same name as static to make it clearer they are separate.
remove unused copy of log_level global var.
remove threequarter sampling variable from the radio board general
configuration. The decision of sampling rate is made above. A better
behavior can be done later, like ask to the radio board what sampling
rate it can do,then use it to decide the appropiate sampling rate from
the gNB configuration. In UE case, it is another issue, as the sampling
rate would change after we decode SIB1, but also it is not developped
yet.
Think: NR with different number of slots per frame depending on mu.
The name 'subframes_per_frame' is a bit ambiguous. It is valid for LTE,
but for NR it should be 'slots_per_frame'.
For example, for sub-carrier spacing of 30KHz, we have 20 slots per
frame, so in this case subframes_per_frame = 20. In reality whatever
the numerology, there is always 10 subframes per frame in NR.
But how to name this variable which is used both for LTE and NR cases?
'subframes_or_slots_per_frame'? It's a bit long and also ambiguous.
Conclusion: no big deal I think. 'subframes_per_frame' and so be it.
- Allow client to exit cleanly if server is down
- Ensure timing_thread is joined only once avoiding exit_function loop
- Free noise_device
- Save previously sent samples for channel modelling
Robert Schmidt