Cleanup PDU Session Handling in RRC/NGAP
Currently, NGAP and RRC share the same structures and responsibilities when
handling PDU Session information: this creates tight coupling, redundancy, and
makes the code harder to maintain.
- NGAP should be responsible only for: Protocol-specific encoding/decoding
(3GPP TS 38.413)
- RRC should own: PDU Session handling and storage in the UE context
This MR is the first step in a broader refactoring of the PDU Session handling
code across NGAP and RRC layers, with the goal of splitting responsibilities
cleanly between both modules.
- Unified gtpu_tunnel_t for tunnel endpoint config (formerly f1u_tunnel_t)
- Refactored and relocated PDU Session struct definitions for better separation
between NGAP and RRC
- Moved pdusession_t for PDU Session handling out of NGAP, now defined and
managed by RRC only
- Defined 3GPP TS 38.413 message-specific structs in NGAP module
- NGAP now decodes NGAP PDU Session Resource Setup/Modify IEs and transfers
decoded data to RRC via ITTI
- Add helper functions to copy from NGAP message to pdusession_t
- Introduced new encoders/decoders/helpers in NGAP for handling PDU Session
Resource Setup/Modify procedures (e.g. decode_pdusession_transfer)
- Migrated to NGAP and removed duplicated logic for QoS information decoding
(fill_qos)
- Improved logging of GTP tunnel info
- Merged redundant functions (f1u_dl_gtp_update and f1u_ul_gtp_update)
- Removed unused code and obsolete types
- do free_func in seq_arr_erase_it on the provided range and updated unit test
- Other fixes and simplifications (e.g. simplified and clarified naming of
tunnel/session parameters and structs)
This cleanup improves code readability, has a high code churn (the deletions are
~159.7% of the insertions) and prepares for better modularity before the
refactoring of PDU Session handling in RRC/NGAP.
Enabling usage of ulsyncvalidityDuration timer in SIB19
ntn-UlSyncValidityDuration in SIB19 from Spec 38.331 v17.12 A validity
duration configured by the network for assistance information which
indicates the maximum time duration (from epochTime) during which the UE
can apply assistance information without having acquired new assistance
information. The unit of ntn-UlSyncValidityDuration is second. Value s5
corresponds to 5 s, value s10 indicate 10 s and so on.
ntn-UlSyncValidityDuration-r17 ENUMERATED{ s5, s10, s15, s20, s25, s30, s35,s40, s45, s50, s55, s60, s120, s180, s240, s900}
Implementation of epochtime is under discussion.
It can be configured in configuration file according to the above
enumeration. For GEO - 240s, MEO - 20s, LEO-5s can be used.
Motivation of the commit:
Previously, the RRC module on the NGAP interface directly handled ASN.1 decoding
of NGAP PDU Session Resource items, that was directly stored in pdusession_t, i.e.
in the UE context. Decode logic between Setup and Modify was also duplicated.,
e.g. fill_qos/fill_qos2. The idea behind this change is to achieve this flow:
(1) NGAP handler: decoding (2) ITTI to RRC: transfer decoded message (3) RRC
handler: process decoded message, e.g. store in UE context, etc..
The goal of this commit is to:
* improve the NGAP decoding library by adding decoding functions
* let RRC handle the already decoded data
* enhance error handling, with decode failures now consistently detected and rejected early
* have a cleaner, more maintainable code with fewer duplications and a clearer separation of modules
Changes:
* Moved all ASN.1 decode logic for PDU Session Resource items into the NGAP library
* Introduced decode functions for NGAP IEs whenever necessary, e.g. decode_TNLInformation
decode_pdusession_transfer
* Removed duplicate fill_qos functions and centralized QoS handling in NGAP
* Added function to copy from NGAP PDU Session Resource item to RRC pdusession_t: this actually
replaces decodePDUSessionResourceSetup in RRC, copying from the decoded NGAP struct to
the UE context pdusession_t
Motivation:
The previous code had overlapping and partially inconsiste definitions of
`pdusession_t` and related structures across NGAP and RRC. This struct type
was used for either the data stored in the UE context and the NGAP message
IEs holding the PDU session to setup/modify information.
This patch aims to separte the `pdusession_t` in RRC, where it logically belongs,
since RRC owns the state of the PDU sessions. NGAP should only
deal with protocol messages, i.e. enc/dec and transfer structures to RRC.
This clarifies module ownership. This also makes the code easier to maintain.
Changes:
* Moved `pdusession_t` definition from NGAP (`ngap_messages_types.h`) to RRC
(`nr_rrc_defs.h`)
* Added a simpler `pdusession_resource_item_t` structure to NGAP for use in
protocol messages
* Adjusted NGAP structures accordingly (Initial Context Setup, PDU Session
Setup Request, and PDU Session Modify Request).
* do decodePDUSessionResourceSetup to decode the NGAP IEs holding PDU session
information and store what necessary in the UE context PDU Session IE: NOTE
this changes were necessary since previously this function was acting on
the common NGAP/RRC pdu_session_t struct
Rename the struct members:
`pdusession_param` to `pdusession` in NGAP Initial Context Setup Request
`pdusession_setup_params` in `ngap_pdusession_setup_req_t`
`pdusession_modify_params` and `ngap_pdusession_modify_req_t`
Motivation:
Clarify the role of GTP tunnel endpoint IDs in PDU session handling. Previously,
the struct members (gNB_teid_N3, UPF_teid_N3, etc.) were confusingly named and
duplicated with separate transport-layer address fields.
This refactoring replaces these with explicit n3_incoming and n3_outgoing members using
gtpu_tunnel_t. This aligns with GTP conventions: "incoming TEID" refers to the
TEID received from the remote peer (UPF on N3), while "outgoing TEID" is the
TEID sent by the local entity (NG-RAN on N3) to the remote peer.
Benefits:
* Improves readability and clarity of the code
* Reduces redundant struct members, i.e. remove UPF_teid_N3, UPF_addr_N3
* Aligns naming with 3GPP conventions for transport layer tunnels
Changes:
* Replace gtp_addr_N3, gNB_teid_N3, gtp_teid, upf_addr with n3_incoming and n3_outgoing
* Update all related code to use the new struct members
* Aligns naming with 3GPP conventions for transport layer tunnels
This struct is used in different layers, e.g. RRC, NGAP: therefore it
has been moved to platform_types.h.
Also, the struct holds the tunnel endpoint configuration for any GTP-U
tunnel, therefore the f1u prefix is not accurate and was updated
to a more generic gtpu.
* Remove drb_is_active: function is unused and the logic will be later
added to another function to add DRBs if necessary
* Remove unused NGAP structs and empty TODO functions
* Remove unused pdusession_setup_req_t struct definition
Suspend RBs at UE
In case of suspended radio bearer (by RRC), the MAC needs to discarded received
PDUs and avoid to transmit using LCID related to that RB
SPEC 38.331 section 5.2.2.6
Inform MAC that UL SYNC got lost because of T430 expiry
- Send message NR_MAC_RRC_CONFIG_RESET with cause UL_SYNC_LOST_T430_EXPIRY to MAC
Reacquire SIB19 after T430 expiry
This is not checked in this commit
- RACH needs to be performed through probably PDCCH order to reobtain UL-SYNC
- system usecase involving Recovery from T430 expiry not tested yet as that requires changes on gNB side.
Spec 38.331 section 5.2.2.4.21 indicates this
1> start or restart T430 for serving cell with the timer value set to ntn-UlSyncValidityDuration for the serving cell
from the subframe indicated by epochTime for the serving cell;
NOTE: UE should attempt to re-acquire SIB19 before the end of the duration indicated by ntn-UlSyncValidityDuration and epochTime
Epochtime IE
When explicitly provided through SIB, or through dedicated signaling, the EpochTime is the starting time of a DL
sub-frame, indicated by a SFN and a sub-frame number signaled together with the assistance information.
For serving cell, the field sfn indicates the current SFN or the next upcoming SFN after the frame where the message indicating the epochTime is received.
This field is mandatory present when ntn-Config is provided in dedicated configuration.
gNB implementation related to epochtime will be done in a separate merge request.
NR UE fallback to RRCSetup from RRCReestablishment
Implementation of the procedure to handle reception of RRCSetup as response
to RRCReestablishment request
[E2 agent] E2AP README update and OAI-FlexRIC CI pipeline improvements
- E2AP README - add OSC nearRT-RIC section; update with proper FlexRIC
links, and explanations on prerequisites, as well as for xApps
- OAI-FlexRIC CI - use separate containers for xApps
- add reference files for CU-UP/CU-CP
- add logging for KPM NSSAI condition
Fix NR reestablishment by implementing the "DRB-suspend" at the MAC.
This means that the during reestablishment, gNB MAC discards received
DRB packets, and does not schedule DRB. Fix a couple of additional
issues in reestablishment. # Please enter a commit message to explain
why this merge is necessary,
For additional information, see
https://gitlab.eurecom.fr/oai/openairinterface5g/-/merge_requests/2668#note_119369
The spCellConfig is to be dropped during reestablishment and to be
applied after reconfiguration. Implement this using the
RRCReconfigurationComplete acknowledgment from the CU to the DU,
applying the spCellConfig if present (which signals a prior
reestablishment). Remove a prior flag that is not needed anymore, and
do not "guess" when is the reconfiguration, because it is now handled in
the case of the ack.
The spCellConfig is not relevant as long as we use a common search space
for DCIs (and the activation of dedicated search space happens after
applying spCellConfig). For PUCCH, there is the PDSCH transmission of
RRCReconfiguration which gets ack'ed in the default PUCCH.
RRCReconfigurationComplete is sent in PUSCH (again through common
search space). In theory, there cannot be another PUCCH before the
application of spCellConfig, as all bearers are still suspended, and
there should not be another SRB1 transmission in the meantime, as only
one RRC transaction can be active at a time.
Co-authored-by: francescomani <email@francescomani.it>
Add a flag for each RB that tracks suspension state. Mark all RBs
(except SRB1) as suspended on reestablishment, and de-suspend on
reconfiguration. Only check RLC status for non-suspended RBs. For UL
data traffic, check that DRB/SRB2 exist (SRB1 should be there as soon as
the UE context exists).
Fix various bugs and inconsistencies in config read, SCTP, ITTI, GTP
Fix bugs across various layers, mostly layer 3, including memory leaks.
See the commits for more details.
SRS configuration
- Fix segmentation fault, a memory leak, and LOGs for SRS usage
NFAPI_NR_SRS_BEAMMANAGEMENT
- Refactor SRS configuration;
- Add SRS ResourceSet to get the SNR measurements at MAC layer
In this MR we have 2 SRS ResourceSet, for the same SRS Resource. This
way, in addition to obtaining the UL-RI, we also obtain the SNR in the
MAC and fill the PRB Black list.
This branch has been tested with COTS UE and with RFSim. The measured
values seem correct.
Using the USIM interface in the MAC is non-sensical (violates layer
separation). Add header include in nr-softmodem.c, which previously came
through nr_mac_gNB.h -> usim_interface.h.
Add configurable values of NR RLC and NR PDCP to the configuration file
This is for the gNB (the UE gets the values from the gNB).
The physical simulators were also adapted (we put the previously
hardcoded values that were everywhere in the code into the simulators
themselves). I don't think we need to have those values configurable for
the simulators, but I can study the possibility to add this if someone
tells me it's important (if not important I prefer not to do it, I am
not sure if it is trivial to do or not).
Add the ability to pack/unpack 2 new TLVs for analog beamforming
total_num_beams_vendor_ext and analog_beam_list
Add the unpack related changes for the first 2 vendor extension TLVs introduced related to beamforming.
For the moment the packing is guarded by an Assert to ensure it is not used.
Add the necessary utility function changes to support these VE TLVs
Add the necessary changes to the corresponding unitary test for pack/unpack,
commented for the moment, since the packing is disabled with an Assert.
Jaroslava Fiedlerova