[E2 agent] RAN Control SM - support for REPORT Style 1 ("RRC Message" and "UE ID" RAN Parameter IDs)
[Spring of Code 2024] contributions
Extended the RAN Control Service Model at E2 Agent to support all RC
REPORT Styles (1 - 5)
Implemented the following RAN Parameter IDs for REPORT Style 1:
1. "RRC Message": any DL-DCCH, and any UL-DCCH
2. "UE ID": as per spec, when the RRC Setup Complete or F1 UE Context
Setup Request detected
Fix inconsistent maxnoofPDUSessions definitions between NGAP and platform constants
There are 2 different definition of maxnoofPDUSessions (as per 3GPP TS
38.413), one in NGAP lib (set to 16) and one in platform_constants.h
(256 as per specs). The NGAP lib definition is removed in this commit
and replaced by the one compliant with the specs.
This is fixing the warning:
In function 'fill_pdu_session_resource_failed_to_setup_item',
inlined from 'rrc_gNB_send_NGAP_INITIAL_CONTEXT_SETUP_RESP' at /openair2/RRC/NR/rrc_gNB_NGAP.c:588:7:
/openair2/RRC/NR/rrc_gNB_NGAP.c:451:12: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
451 | f->cause = cause;
| ~~~~~~~~~^~~~~~~
In file included from /common/utils/ocp_itti/intertask_interface.h:235,
from /openair2/RRC/NR/rrc_gNB_NGAP.h:39,
from /openair2/RRC/NR/rrc_gNB_NGAP.c:31:
/openair2/COMMON/ngap_messages_types.h: In function 'rrc_gNB_send_NGAP_INITIAL_CONTEXT_SETUP_RESP':
/openair2/COMMON/ngap_messages_types.h:546:13: note: at offset [8724, 25769812488] into destination object 'gNB_ue_ngap_id' of size 4
546 | uint32_t gNB_ue_ngap_id;
| ^~~~~~~~~~~~~~
As per spec, UE ID shall be reported when the message event configured by
the Event Trigger Style 1 is set to “RRC Setup Complete" message (UE attach), or
“Xn/NG Handover Request” or “F1 UE Context Setup Request” (Intra gNB Handover).
In OAI RAN, Xn/NG Handover is not yet supported, and therefore not added as the trigger event
in this commit.
Additionally, as the Event Trigger Definition Format 1 is common for both "RRC Message" and "UE ID",
E2 node will report the “RRC Setup Complete" message which the xApp will decode and print.
Co-authored-by: Khanh Toan Pham <khanh.toan.pham@hhi.fraunhofer.de>
Co-authored-by: Shrinish Donde <shrinish.donde@hhi.fraunhofer.de>
Co-authored-by: Theodoros Tsourdinis <theodoros.tsourdinis@sorbonne-universite.fr>
Co-authored-by: Miguel Fuentes <miguel.fuentes@i2cat.net>
Co-authored-by: Teodora Vladic <teodora.vladic@openairinterface.org>
Fixes for E1 and PDU session usage
Fix a number of problems in E1 and PDU session handling:
- For multiple PDU session setup reqs, we send a bearer context setup
each time; fix an assert that was triggered on the second bearer
context setup message
- Add a log for E1 bearer context setup, as already done for
modification and release
- If we get a PDU session setup for an existing PDU session, reject it
as required by the spec [actually, it says to reject individual PDU
sessions; keep it simple for now and reject the entire message, which
might not be correct if there is one new PDU session that does not
exist]
- Add a workaround to handle multiple PDU session setup requests that
come in quick succession for different PDU sessions
Leading to clang error:
/oai-ran/openair2/RRC/NR/rrc_gNB_NGAP.c:1329:37: error: result of comparison of constant 256 with expression of type
'uint8_t' (aka 'unsigned char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
The value comes from the decoding of: ie->value.choice.PDUSessionResourceToReleaseListRelCmd.list.count
There are 2 different definition of maxnoofPDUSessions (as per 3GPP TS 38.413),
one in NGAP lib (set to 16) and one in platform_constants.h (256 as per specs).
The NGAP lib definition is removed in this commit and replaced by the one
compliant with the specs.
This is fixing the warning:
In function 'fill_pdu_session_resource_failed_to_setup_item',
inlined from 'rrc_gNB_send_NGAP_INITIAL_CONTEXT_SETUP_RESP' at /openair2/RRC/NR/rrc_gNB_NGAP.c:588:7:
/openair2/RRC/NR/rrc_gNB_NGAP.c:451:12: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
451 | f->cause = cause;
| ~~~~~~~~~^~~~~~~
In file included from /common/utils/ocp_itti/intertask_interface.h:235,
from /openair2/RRC/NR/rrc_gNB_NGAP.h:39,
from /openair2/RRC/NR/rrc_gNB_NGAP.c:31:
/openair2/COMMON/ngap_messages_types.h: In function 'rrc_gNB_send_NGAP_INITIAL_CONTEXT_SETUP_RESP':
/openair2/COMMON/ngap_messages_types.h:546:13: note: at offset [8724, 25769812488] into destination object 'gNB_ue_ngap_id' of size 4
546 | uint32_t gNB_ue_ngap_id;
| ^~~~~~~~~~~~~~
This is a hack. With some UEs/CN combinations, PDU session requests
might come in quick succession. Since 38.331 asks us to only have one
reconfiguration at once, we need to delay a second, third, ... PDU
session request until the first has passed, to make one reconfiguration
at a time.
38.413 section 8.2.1.4 says that if PDU session resource setup req
contains an existing PDU session, that one should be reported as failed.
That is rather complicated for us to do; simply reject all PDU sessions
and let the core deal with that.
* Use the 5G-S-TMSI stored in RRC to be used as UE identity
* Use 5G-S-TMSI part 1 in RRCSetupRequest encoding (TS 38.331 clause 5.3.3.3)
* Set the ng-5G-S-TMSI-Value in RRCSetupComplete to ng-5G-S-TMSI-Part2 (5.3.3.4 of 3GPP TS 38.331)
* current and only scenario: RRCSetup is received in response to an RRCSetupRequest
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
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.
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.
As in deba3ae066 ("Reset CU-UP E1 UE contexts after E1 Setup
Response"), the CU-CP should reset the 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.
In the case of CU-CP, this is a bit more complicated. More precisely, we
need to wait for the CU-UP to be available again before informing the DU
about the loss (implemented via an F1 Reset message), because otherwise,
the UE might reconnect immediately, before the CU-UP is online again.
Hence, on connection loss, we mark affected UEs (by setting their E1
association ID to 0); as long as the CU-UP does not connect, nothing
will happen (but UEs don't have user plane). Upon CU-UP connecting
again, we request release of the UEs via NGAP (similarly to what is done
if the DU goes offline, see invalidate_du_connections()), free the UE
contexts locally, and send an F1 Reset message to the DU, because
38.473 sec 8.2.1.2.1 says
> a failure at the gNB-CU [...] has resulted in the loss of some or
> all transaction reference information [...] a RESET message shall be
> sent to the gNB-DU.
The core should accept and send an NGAP release command message; since
no UE contexts are to be found (already deleted), the CU-CP will just
send a release complete (together with some warnings).
It might be possible to more gracefully handle the situation (e.g., as
described in 38.401 section 8.9.5 "Change of gNB-CU-UP"), but
- we lack the PDCP SN exchange
- the current procedure has the advantage of being equivalent to
"restart of the entire gNB", with less downtown.
The next commit will use rrc_remove_ue() to delete a CU(-CP+-UP)
context. However, we don't send NGAP UE context release at that moment
(we will instead *request* the release); more generally, it's not clear
that every user of rrc_remove_ue() wants to actually send this message.
Hence, refactor the code by separately calling
rrc_gNB_send_NGAP_UE_CONTEXT_RELEASE_COMPLETE() where appropriate.
Bearer context setup request and modification request messages
differ in various IEs according to 9.2.2 of 3GPP TS 38.463, e.g.
the Bearer context setup request does not contain a list of
DRBs to modify and does not contain an UP TL configuration.
Thus, the goal of this commit is to split the setup request message
and the modification request into two different structs:
* adopt e1ap_bearer_mod_req_t where necessary (e.g. fill_e1_bearer_modif)
Also, reorganized existing struct members according to specs:
* remove irrelevant struct members from the setup request
* group members from the same IEs into structs
* set optional struct members IEs as pointers
* add and adopt enc/dec/cp/eq lib functions for single IEs
* add UP_TL_information_t struct with TEID and TL address info and adopt in stack
* use int instead of long for count types
* update the relevant copy/equality check utility functions
Extra:
* add a function to handle Security Information in RRC in the process
* add create_up_tl_info and adopt in unit tests
Changes to support multiple TDD patterns
- Updated the configuration changes for 2 Patterns
- Update the TDD table configuration for NFAPI
- Added the tdd bitmap for the period
- Adapted the bitmap for UL/DL for the multi TDD pattern
- Updated the RACH procedure for multi TDD pattern
- Updated DL and UL scheduler for multi TDD pattern
francescomani