Fix bug "no AMF for UE"
It might happen that the RRC does not know the AMF UE NGAP ID, yet. Even
in that case, we should forward the release request to the NGAP module,
which can either forward a message to the AMF, or reply back to release
the UE. This avoids an error where the CU claims there was no AMF, when
there actually is.
One possible problematic behavior is if a UE disconnects before the gNB
receives an NGAP Initial Context Setup. In this case, the AMF UE NGAP ID
was not forwarded to the RRC (although it was known at NGAP), thus
blocking the release of the UE.
This is the main fix, the rest are minor fixes:
- store AMF UE NGAP ID as early as possible
- warn in MAC if UE unknown for UE context release command
- show TEIDs with correct endianness in GTP
- avoid NG Setup Failure+Setup log.
Introduce SRS physical simulator and improvements
This MR consists of two parts:
- Introduces SRS physical simulator to test different configurations of
SRS
- Improvements in the SRS channel estimation (Addressing the comments
from old, unfinished MR !2875)
- rewrite nr_srs_channel_estimation() to loop over rx antennas and
antenna ports to be able to parallelize
- Improvements in timing_advance_offset and timing_advance_offset_nsec
computation
- Introduce SRS multi-symbol channel estimation
- The channel impulse response is estimated from the averaged
channel frequency response over multiple symbols
- The channel frequency estimates are left as they are to be able to
estimate doppler in the future
- Simplify SRS channel estimation to handle memory alignment in the
case of different SRS configurations (eg: comboffset)
To use multiple symbols when running gNB, the following parameters needs
to be edited in the function get_srs_resource()
- srs_res->resourceMapping.startPosition with a range from {0,1,..,5}
corresponds to the start symbol {13, 12, .. 8} with in a slot
- srs_res->resourceMapping.nrofSymbols indicates the number of symbols
{n1, n2, and n4}
Make sure the that start symbol + number of symbols is < 14
The timing results for SRS in develop and srs_phy_simulator are as follows:
Command used: sudo ./nr_ulsim -n1000 -s50 -S50 -R273 -W2 -y2 -z2 -E 1 -P
develop
|__ RX SRS time 124.94 us (1000 trials) (124.94 total [ms])
|__ Generate SRS sequence time 0.05 us (1000 trials) ( 0.05 total [ms])
|__ Get SRS signal time 19.41 us (1000 trials) ( 19.41 total [ms])
|__ SRS channel estimation time 89.11 us (1000 trials) ( 89.11 total [ms])
|__ SRS timing advance estimation time 13.10 us (1000 trials) ( 13.10 total [ms])
|__ SRS report TLV build time 2.80 us (1000 trials) ( 2.80 total [ms])
|__ SRS beam report build time 0.00 us ( 0 trials)
|__ SRS IQ matrix build time 2.73 us (1000 trials)
srs_phy_simulator
|__ RX SRS time 211.93 us (1000 trials) (211.93 total [ms])
|__ Generate SRS sequence time 0.04 us (1000 trials) ( 0.04 total [ms])
|__ Get SRS signal time 19.55 us (1000 trials) ( 19.55 total [ms])
|__ SRS channel estimation time 152.05 us (1000 trials) (152.05 total [ms])
|__ SRS timing advance estimation time 36.67 us (1000 trials) ( 36.67 total [ms])
|__ SRS report TLV build time 2.96 us (1000 trials) ( 2.96 total [ms])
|__ SRS beam report build time 0.00 us ( 0 trials)
|__ SRS IQ matrix build time 2.88 us (1000 trials)
Note that in srs_phy_simulator, to compute timing offset ns, an
oversampling factor of 2 is performed. Also, for peak detection, we
average the channel estimates for every port.
gNB: apply new NR_CellGroupConfig when RRCReconfiguration is acknowledged
Currently part of the NR_CellGroupConfig is already applied when the
RRCReconfiguration message is created. This is not correct and this MR
fixes this by applying it when the RRCReconfiguration message is
acknowledged.
With this fixed, we also move disabling the feedback (in case
disable_harq is used) from the RRCSetup message to the
RRCReconfiguration message.
Closes: #1002
Reset outdated PUCCHs to avoid Assertion caused by non-processed and
active PUCCHs
When there is real-time issues in L1 it may happen that the scheduler
misses/skips some slots, thus, L2 not processing and not freeing some
structures like PUCCH. This commit avoids the Assertion by resetting
any Active outdated PUCCH
When doing analogue beamforming, the beam ID for a pre-defined beam
table is passed directly to RU and there is no need to store the beam
table in PHY.
When there is real-time issues in L1 it may happen that the scheduler misses/skips some slots, thus, L2 not processing and not freeing some structures like PUCCH.
This commit avoids the Assertion by resetting any Active outdated PUCCH
In all cases (CFRA in SA for HO, or CFRA in NSA/do-ra for access), the
UE has the full configuration already. We can therefore directly switch
to a dedicated search space, as it is already known to the UE.
... so if we want to have 1 BWP configured at any given time we need to
reconfigure BWP 1 every time. This means that since the gNB has more
than 1 BWPs (for use for different UEs), that there is a "gNB BWP ID"
(as used by the gNB), which can be any BWP ID X, and one "UE BWP ID",
which is always 1. This commit implements this distinction.
Return from triggering reconfiguration with BWP switch if BWP is the
same as before the switch, and add check to verify if BWP triggered by
switch command exists
CFRA: mark RA complete when sending Msg2
The current contention-free random access forces a "Msg3" (which does
not exist in CFRA) to be received by a UE. Sometimes, this "Msg3" is not
received (for whatever reason), and the MAC declare that RA failed.
This is problematic, as the spec says that RA is complete once Msg2 is
received by the UE. Since the gNB cannot know when this is, simply mark
it as complete once we sent Msg2.
We still send Msg3 in CFRA, which is explained further in the commits.
Also, improve logging and stabilize an RFsim test by reducing sl_ahead.
Since the parent commit, CFRA is inconditionally marked complete on Msg3
reception (successful or not). This works because the current
implementation still sends a UL grant (see parent commit for details).
In this commit, handle Msg3 if received in CFRA (notably for TA and
power). Note that since we declare RA complete, UE->ra does not exist
anymore, and so an intermediate variable is introduced to capture the
CFRA flag. The code should be such that if we are in CFRA, we never
access any UE->ra variable.
The current contention-free random access forces a "Msg3" (which does
not exist in CFRA) to be received by a UE. Sometimes, this "Msg3" is not
received (for whatever reason), and the MAC declare that RA failed.
This is problematic, as the spec says that RA is complete once Msg2 is
received by the UE. To avoid this, inconditionally mark RA as complete
as soon as we receive an indication of Msg3 (DTX or not).
Note that after this change, we still send a UL grant in Msg2. This is
because 38.321 §5.1.4 is not clear to me whether we should send UL grant
(it does not explicitly exclude it), and it says
> 3> if the Random Access Response includes a MAC subPDU with RAPID only:
> [...]
> 4> indicate the reception of an acknowledgement for SI request to
> upper layers.
which is NOT the case (but then I don't know/think we can have CFRA for
SI request?). Since it also works with COTS UE, I leave Msg3 for the
moment.
The reason to not directly mark RA as complete when sending Msg2 is
because of possible retransmissions in do-ra mode. In fact, in do-ra,
there might already be data awaiting. In that case, the DLSCH scheduler
schedules data _in the same slot as Msg2_, which the UE does not decode,
leading to retransmissions.
Fix reestablishment after handover
- fix reestablishment by not re-creating LCIDs with priority set to 0 (see first
commit for more details)
- cleanup code
The idea is to reestablish all RLC entities (it's a new UE, and we set
reestablishRLC on all bearerrs), so we should reestablish all RLC
entities on gNB side as well, without any additional loop.
Co-authored-by: Roberto Magueta <rmagueta@allbesmart.pt>
Move the file process_addmod_bearers_cellGroupConfig() to the file where
it is used. Correctly set priorities as requested in RLC bearer
configuration.
In all cases (NSA, HO), we create LCIDs before the UE triggers random
access. Hence, process_addmod_bearers_cellGroupConfig() is not
necessary, as it just tries to recreate an LCID.
Furthermore, it includes a bug, as this function does set a wrong
priority (0), so the sorting of LCIDs is not correct. This in turn
creates problems with reestablishment, as LCID 1/SRB1 is not in the
first position, making reestablishment fail (where we assume LCID 1 be
in first position).
The actual bug of setting priorities is fixed in the next commit.
Robert Schmidt