The "writeTimestamp inconsistencies" are coming from the fact that during the actual processing we write `N_TA_offset` samples _and_ `NR_UE_CAPABILITY_SLOT_RX_TO_TX` slots ahead,
but both was not corrently considered in readFrame() and syncInFrame().
Therefore, there was always a warning about a gap in write timestamps as soon the actual processing starts.
The value of ntn_init_time_drift is used at initial sync to compensate for the time drift during initial sync detection.
To perform the initial time and frequency sync, the OAI UE currently takes a snapshot of two frames and then performes PSS correlation, SSS detection and MIB decoding.
Doing this takes much time, several tens of ms. During that time, the DL timing drifts so much, that we immediatedly lose sync again.
Therefore the current OAI UE implementation needs to know the drift rate to compensate for this drift, as we are "blind" while performing the initial sync.
To my undestanding, commercial UEs simply have a faster initial sync, so the DL timing will not drift away too much while performing that initial sync.
Add check on force_local in custom_command CI handling
The force_local flag was introduced earlier in the main CI script in
order to run a CI test locally.
The flag was still missing in the Custom_Command handling, which was
still targeting the node specified in the test configuration file. This
was causing a failure in the tests with custom commands and therefore
limiting the scenarios that could be run locally.
With this commit, if force_local is enabled the node for the
Custom_Command is set to localhost.
Refactor and extend NAS Registration Request
Extended NAS Registration Request generation and encoding according to
8.2.6 of 3GPP TS 24.501. Main topics:
- NAS Registration Type
- NAS KSI
- integrity protection
- NAS container encoding
Improvements:
- Add 5GMM Modes in NAS
- Introduced 5GMM state machine
Fixes:
- add 5GMM Capability IE to Registration Request
- closes#881, #819
Dynamic PDCCH aggregation level
The aggregation level search order for PDCCH candidates is modified:
- the search starts from desired_agg_level_index, which is a value from
0 to 4 proportial to pdcch_cl_adjust.
- pdcch_cl_adjust is a value between 0 and 1 that indicates PDCCH
channel quality by averaging HARQ DTX rate. A value of 0 means perfect
channel, a value o 1 means impaired channel.
Also added configuration option for number of PDCCH candidates per
aggregation level.
The aggregation level search order for PDCCH candidates is modified:
- the search starts from desired_agg_level_index, which is a value from 0 to 4
proportial to pdcch_cl_adjust.
- pdcch_cl_adjust is a value between 0 and 1 that indicates PDCCH channel quality
by averaging HARQ DTX rate. A value of 0 means perfect channel, a value o 1 means
impaired channel.
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
Some radios (e.g., RFsim) can run faster. A mechanism has been put in
place to keep RX/TX frame/slot numbers not too far from each other.
Refactor in a separate function with documentation to make this clearer.
* The force_local flag was introduced earlier in the main CI script
in order to run a CI test locally. The flag was missing in the
Custom_Command handling, which was still targeting the node specified
in the test configuration file. With this commit, if force_local
is enabled the node for the Custom_Command is set to localhost.
Integration: `2025.w06`
See merge request oai/openairinterface5g!3248
* !3202 Simplify usage of the old segment decoding libraries with the slot coding interface
* !3240 Fix typos in NR_SA_Tutorial_OAI_multi_UE.md
* !3242 Period based phytest bitmap
* !3238 Refactor tun_if.h
* !3000 Improvements for NR dlsim and ulsim
* !3239 Remove inexistant SIMD instruction
* !3246 Deadlock avoidance in rfsimulator
* !3251 nFAPI: make 4-layer on 100MHz work
* !3243 Reset E1 UE contexts after E1 Setup Response
* !3245 Added Support of 35Mhz,45Mhz,70Mhz Bandwidth
* !3219 E1AP enc/dec lib improvements
E1AP enc/dec lib improvements
This MR is including some fixes and improvements for the E1AP library,
focusing mostly on Bearer Context Management:
- struct reorganization: split setup and modification request messages
into distinct structures, ensuring compliance with 3GPP TS 38.463
specifications
- add encoding/decoding sub-functions for different IEs
- improvements to Bearer Context Management: Implemented various
improvements to the E1 Bearer Context Setup Response and Request,
including the adoption of encoding/decoding sub-functions for
different IEs
- use lib functions whenever need (e.g. cp_bearer_context_setup_request
in cucp_cuup_e1ap.c)
- handle optional struct members as pointers
- updated copy/equality check utility functions
EDIT: The MR is also including the changes from !3222 (closed):
> While testing E1 with security enabled for DRBs, it was found that
> data traffic was not functional.
>
> The problem was that security settings were modified in the PDCP
> reestablishment happening when receiving Bearer Context Modification
> Request.
>
> So some restructuring was done.
>
> The actual fix is in 18176297, the others are for support. Basically
> we introduce a boolean to check if the security settings are present in
> Bearer Context Modification Request and we change PDCP security settings
> only if they are.
>
> (Note that in OAI CU security settings are not sent in Bearer Context
> Modification Request, so we could also remove all this, but we need to
> be compatible with other cu-up and/or cu-cp.)
Added Support of 35Mhz,45Mhz,70Mhz Bandwidth
Added Support of 35Mhz,45Mhz,70Mhz Bandwidth for 30Khz Subcarrier
Spacing, Also added 35Mhz, 45Mhz bw for 15Khz Subcarrierspacing.
Referred Spec TS 38.101 v18.6.0 section 5.3.2, table 5.3.2-1
Reset E1 UE contexts after E1 Setup Response
38.463 sec. 8.2.3 says
> This procedure also re-initialises the E1AP UE-related contexts (if
> any) and erases all related signalling connections in the two nodes
> like a Reset procedure would do.
Hence, delete all contexts after reception of E1 Setup Response. This
minimizes a risk of receiving an E1 bearer setup req for an existing UE,
which currently leads to an assert [we trust the CU-CP does not send the
same UE ID twice, as we only "mirror" the existing UE ID]. After this
MR, this is what happens if these entities fail:
- CU-CP fails: all context lost implicitly, upon reconnection, both DU
and CU-UP reset all contexts (like "start from zero")
- DU fails: CU-CP triggers NGAP UE context release request immediately
(radio connection with UE lost), all UE contexts attached to this DU
cleared (like "start from zero" for affected DU)
- CU-UP fails: initially, nothing (UE has no user plane); upon
reconnection of CU-UP, CU-CP triggers NGAP UE context release request
(cause radio connection with UE lost) and sends F1 Reset to DU, all UE
contexts associated to this DU cleared (like "start from zero")
for the last case, a possible improvement could be to use the F1 Reset
message to only clear affected UE conetxts. I chose not to do this,
because this MR is very big now already, and possible "victim" UEs
that were not at that CU-UP will reconnect as well
In Bearer Context Modification Request, the security information
field is needed only if we change the PDCP algorithms/keys. Since we
don't, no need to pass it.
Let's keep the old code, maybe the current understanding of the
specifications is wrong.
If the Bearer Context Modification Request does not contain security
information, the PDCP entity shall keep the currently configured security
settings.
Passing -1 for ciphering_algorithm and integrity_algorithm is the way
to implement this logic.
Check if the IE is memory allocated to deal with presence/absence of this information
element in Bearer Context Modification Request and add encoding/decoding
in the code.
Note that for decoding the integrity settings may be absent, in which
case we consider NIA0 to be used (no integrity protection). To be refined
if needed.
And for encoding, we always encode integrity settings, even if it's NIA0.
May also be refined if needed.
This was not a big problem, but we were advertising wrong
algorithm and deriving keys using this wrong algorithm in case
DRB ciphering and/or integrity was not active. (Say SRBs
are configured with NIA2 but DRBs are configured without
integrity, we would advertise NIA2 and send the integrity
key derived for NIA2, instead of NIA0 for both.)
It was not a problem because in the PDU Session Resource To Setup
item, there is "securityIndication" which we use to effectively
activate/deactivate the ciphering and/or integrity.
But it did not look clean to see a SecurityInformation with
incorrect data when inspecting the message in wireshark.
So let's use the correct values.
We could also not include the SecurityInformation if both ciphering
and integrity are not used, and only include ciphering if integrity
is not used (because integrity settings are optional).
But then if only integrity is used, we still need to include
ciphering, setting algorithm to NEA0 (no ciphering), because
the ciphering settings are always included.
This logic is too complex, let's use the simple one to always
include SecurityInformation with NEA0 and/or NIA0 if ciphering
and/or integrity is not activated.
Thomas Schlichter