Seems like the UEs in the CI don't like when asked to report NR UE
capabilities. So let's first ask for eutra capabilities and then
dig into them to check for en-dc support and only then ask for
NR capabilities. We chose to ask for NR capabilities after receiving
RRCConnectionReconfigurationComplete. That may not be the best thing
to do.
Today, we do nothing with those capabilities. We could completely skip
asking them to the UE, but since the code is there and since it may be
useful in the future, let's do it. Hopefully, it should not hurt too much.
An NR-capable UE will transmit some NR measurements.
Once received, the whole process on nr-cell addition is started.
It will fail quickly.
Many things are still missing.
What is not handled properly with this commit:
- in x2ap_eNB_handle_sgNB_add_req we hardcode the gNB ID
- nr triggering is done if we receive a measurement but this measurement is
not analyzed at all
- no timers (T_dc_overall, T_dc_prep) and as is the code fails and then the
next triggering after UE reconnection will not work (x2 ID are not well
handled here and there in the code)
Note also that the gNB part has not been looked at all for this commit.
This is work in progress...
This commit introduces X2AP timers (t_reloc_prep, tx2_reloc_overall).
You need to set the values in the configuration file.
X2AP can be enabled or disabled in the configuration file too (disabled
by default).
Some deadcode was removed.
Some deadcode was removed.
The implementation of the ID management is not finished.
It will only work if the handover is successful. No error
recovery has been done. For error recovery, we need to
implement the X2AP timers. As it is, in case of error, an ID
might very well never be released.
It has been tested with 1 and 2 UEs doing handover more or less
at the same time.
- manage target eNB based on target cell id received by measurement report
for Handover Request
- manage source eNB based on association id for Handover Request Ack
- use only x2ap instance and not x2ap data instance points to x2ap instance
With the introduction of X2AP into develop, the UEs now have to regularly
send measurement reports.
In the logs of the eNB, we see:
[OSA] Mismatch found in integrity for algorithm 2,
got e0.a0.c2.66, expecting a5.9c.cb.57
[PDCP] [OSA][RB 1] eNB failed to validate MAC-I of incoming PDU
This is a bug in the PDCP layer that uses wrong parameters to compute the
integrity.
This commit fixes this bug.
The function pdcp_is_rx_seq_number_valid was removed. Its processing
has been directly integrated into the function pdcp_data_ind.
The function pdcp_mark_current_pdu_as_received is not called anymore.
Its processing was not used later on, so as of today, not calling it does
not introduce any functional change.
The function pdcp_validate_security takes now as parameters both
SN and HFN. Same for the function pdcp_get_next_count_rx.
Useless constants PDCP_SN_5BIT, PDCP_SN_7BIT and PDCP_SN_12BIT have been
removed.
The compilation option ENABLE_SECURITY has been removed. It's now always
on. (This may impact some use cases.)
The PDCP for DRB using RLC AM is not correct. It was not correct before
this commit (apart from the integrity bug). We should deal with a list
of PDUs and transmit packets to upper layers as detailed in the specs.
Today we transmit the PDU as soon as we get it. We don't care about
duplicates, in-order delivery, timeouts.
Also, we don't deal with "PDCP re-establishment". Not sure how that impacts
the software.
And, last but not least, there is still no ROHC.
Connection goes until generation of RRCConnectionSetup in CU which crashes (it calls rrc_mac_config_req. For DU this should be replaced with filling DL_RRC_MESSAGE_TRANSFER
s.rampalli