Content for TS 23.369 Word version: 19.1.0
6 AIoT Procedures
6.1 General
6.2 AIoT Service Procedures
6.2.1 General
6.2.2 Inventory Procedure
6.2.3 Command Procedure
6.2.4 Procedures between AIOTF and NG-RAN for Indirect Connectivity
6.2.4.1 Overview
6.2.4.2 Message delivery to NG-RAN
6.2.4.3 Message delivery to AIOTF
6.2.5 AIoT Session Release Procedure
6 AIoT Procedures p. 24
6.1 General p. 24
Clause 6.2 describes the AIoT procedures and Network Function services for the 5GS by end-to-end information flows and making use of the NF service operations defined in clause 7, in those information flows.
6.2 AIoT Service Procedures p. 24
6.2.1 General p. 24
Clause 6.2.2 provides the procedure for AIoT Inventory. Clause 6.2.3 provides the procedure for AIoT Command. Clause 6.2.5 provides the AIoT Session release procedure for AIoT Inventory and AIoT Command.
6.2.2 Inventory Procedure p. 24
Figure 6.2.2-1 describes the inventory procedure.
The procedure focuses on the messages and parameters used for the communication between AIOTF and NG-RAN regardless of the path to access NG-RAN, see clause 4.2.2.1. The handling of the different communication paths is described in clause 6.2.4.
Step 1.
The AF invokes Nnef_AIoT_Inventory Request (AF ID, [External Target Area information], [information about the target AIoT Device(s)], [Approximate number of AIoT Devices], [time interval], [location information requested]) service operation request to the NEF.
Information about the target AIoT Device(s) may include Filtering Information, as described in clause 5.8, or include complete AIoT Device Identifier(s).
The approximate number of AIoT Devices, if provided, is used to determine the number of AIoT Devices expected to respond to this inventory AIoT service operation request, which is sent by AIOTF to the NG-RAN in the assistance information for NG-RAN in step 7 for proper radio resource allocation.
The time interval, if provided, is described in clause 5.9.
The location information requested parameter indicates whether the AF expects the network to provide the device location information.
Step 2.
The NEF may further authorize the AF request as specified in clause 5.6.
The NEF determines the Target Area information from the External Target Area information, and selects one or multiple AIOTF(s) to handle the request as specified in clause 5.3.1. If no AIOTF can be selected, the NEF rejects the Nnef_AIoT_Inventory request with an appropriate cause code and step 6 is performed before ending the procedure.
Step 3.
The NEF invokes the Naiotf_AIoT_Inventory (AF ID, [Target Area information], [information about the target AIoT Device(s)], [Approximate number of AIoT Devices], [time interval], [location information requested]) service operation towards each of the selected AIOTF(s).
Step 4.
The AIOTF receives the Naiotf_AIoT_Inventory request and checks the parameters included in the request. The AIOTF may perform authorization as specified in clause 5.6. If the AIoT service operation request cannot be processed, the AIOTF rejects the AIoT service operation request with an appropriate cause code, and step 7 onwards are skipped.
The AIOTF generates a Correlation ID corresponding to this AIoT service operation request and the Correlation ID is used for the AIOTF to correlate the service operation responses received from NG-RAN to the AIOTF request. The AIOTF creates the AIoT Session for the AF service operation request, which is identified by the Correlation ID.
The AIoT Identification Information to be provided to NG-RAN can include Filtering Information, as defined in clause 5.8, or a single AIoT Device Identifier.
The AIOTF performs Reader Selection, see clause 5.3.3. If no NG-RAN or RAN Reader can be selected, the AIOTF rejects the AIoT service operation request with an appropriate cause code.
The AIOTF determines assistance information as described in clause 5.4, taking into account the parameters provided in the AIoT service operation request.
The AIOTF may perform AMF selection as described in clause 5.3.4.
Step 5.
AIOTF sends the AIoT Inventory Service Response to the NEF containing the accept or reject result for the AIoT service operation request based on step 4.
Step 6.
NEF sends the AIoT service operation response to the AF, containing the accept or reject result for the AIoT service operation request as specified in clause 8.3.
Step 7.
The AIOTF sends the Inventory Request message including the Correlation ID, the AIoT Identification Information to be included in the paging message, Requested Service Area Information and assistance information to the selected NG-RAN as specified in TS 38.413.
Step 8.
The NG-RAN sends an Inventory Response to the AIOTF with the Correlation ID indicating that the Inventory Request is received successfully and will perform the AIoT service operation accordingly as specified in TS 38.413. If the Inventory Request is not rejected, then an AIoT Session is created in the NG-RAN. After this step, the AIoT Session between the NG-RAN and AIOTF identified by correlation ID is established.
Step 9.
Upon reception of the Inventory Request message from the AIOTF, the RAN Reader(s) will execute the inventory operation as specified in TS 38.300 and TS 38.391. The RAN Reader(s) broadcast the paging message that includes the AIoT Identification Information.
The AIoT Device determines whether it matches the AIoT Identification Information, as described in clause 5.8.
If an AIoT device matches the AIoT Identification Information in the paging message, the AIoT Device responds to the paging message and sends an AIOT NAS message that includes its AIoT identity.
Step 10.
NG-RAN sends one or more Inventory Report messages to the AIOTF including the Correlation ID, Reader ID and the AIOT NAS message(s) from the AIoT Device(s) as specified in TS 38.413. The NG-RAN may aggregate multiple Inventory Report messages based on the assistance information before reporting the response to the AIOTF as described in clause 5.9. The AIOTF stores the mapping between the Reader ID and AIoT Device ID(s).
Step 11.
The AIOTF validates the results, using local stored device information or device profile data retrieved from the ADM. The AIOTF may aggregate the results.
Step 12.
Optionally, if the NG-RAN detects that no more AIoT Devices will respond to the inventory procedure, the NG-RAN informs the AIOTF that the procedure is complete and the last inventory result. After the procedure has completed NG-RAN will not send any further Inventory Reports for this requested Inventory.
Step 13.
The AIOTF reports the progress of the Naiotf_AIoT_Inventory request to the NEF by sending the Naiotf_AIoT_Notify message including a list of AIoT Device Permanent Identifier (s) and optionally location of each AIoT Device. The AIOTF may send multiple reports.
Based on operator policy, if the location information is requested by the AF and if the location of the reader is configured, the AIOTF uses the Reader ID reported from NG-RAN in step 10 to determine the AIoT Device Location.
The AIOTF in the final Naiotf_AIoT_Notify message indicates it is the last report for this operation. When the last report is sent, the AIOTF ends the AIoT Session. If multiple AIOTFs are involved in the procedure, the NEF may receive Naiotf_AIoT_Notify 's from multiple AIOTFs.
Step 14.
When receiving the Naiotf_AIoT_Notify message from AIOTF, the NEF informs the AF of the outcome of the Nnef_AIoT_Inventory request by sending the Nnef_AIoT_Notify message(s) including the AIoT Device Permanent Identifier(s) and optionally location of each AIoT Device. The NEF in the final Nnef_AIoT_Notify message indicates that it is the last report for this operation.
6.2.3 Command Procedure p. 27
Figure 6.2.3-1 depicts the command procedure.
The procedure focuses on the messages and parameters used for the communication between AIOTF and NG-RAN regardless of the path to access NG-RAN, see clause 4.2.2.1. The handling of the different communication paths is described in clause 6.2.4.
Step 1.
If none of successful Inventory response is received, Step 8 -11 is not performed and the AIOTF sends a failure report to the NEF in step 12.
The AF sends the Nnef_AIoT_Command Request (AF ID, Command Type, information about the target AIoT Device(s), [External Target Area information], [Approximate number of AIoT Devices], [Approximate D2R message size], [Command type specific parameters], [location information requested]) message to NEF.
Information about the target AIoT Device(s) may include Filtering Information, as described in clause 5.8, or include complete AIoT Device Identifier(s).
The approximate number of AIoT Devices (see clause 5.4), if provided, is used to indicate the number of AIoT Devices expected to respond to this AIoT service operation request, which is sent by AIOTF to the NG-RAN in the assistance information as specified in clause 5.4.
Command Type provides the operation to be performed and the Command type specific parameters provides the required parameters for the operation. The service operations are described in clause 5.2.2.
Step 2.
Step 2 of the Inventory Procedure specified in clause 6.2.2 is performed for External Target Area information processing and AIOTF selection with the following clarifications:
Step 3.
-
If AIOTF selection fails, the NEF rejects the Nnef_
AIoT_ request and step 6 of this procedure is performed instead.Command
The NEF sends Naiotf_AIoT_Command Request message (AF ID, Command Type, information about the target AIoT Device(s), [Target area information], [Approximate number of AIoT Devices], [Approximate D2R message size], [Command type specific parameters], [location information requested]) message to the selected AIOTF(s).
Step 4.
The AIOTF receives the Naiotf_AIoT_Command Request and checks the parameters included in the request. The AIOTF performs Reader Selection as specified in clause 5.3.3. If no NG-RAN or RAN Reader can be selected, the AIOTF rejects the AIoT Command request with an appropriate cause code.
The AIOTF generates a Correlation ID corresponding to this AIoT service operation request and the Correlation ID is used for the AIOTF to correlate the service operation responses received from NG-RAN to the request. The AIOTF creates the AIoT Session for the AF service operation request, which is identified by the Correlation ID.
The AIOTF performs Reader Selection, see clause 5.3.3. If no NG-RAN or RAN Reader can be selected, the AIOTF rejects the AIoT service operation request with an appropriate cause code.
The AIOTF determines assistance information as described in clause 5.4, taking into account the parameters provided in the AIoT service operation request.
The AIOTF performs AF authorization for AIoT service operation request as described in clause 5.6.
The AIOTF may perform AMF selection as described in clause 5.3.4.
Step 5.
AIOTF sends the Naiotf_AIoT_Command Response message (accept or reject, [cause code]) to the NEF.
Step 6.
NEF sends the Nnef_AIoT_Command Response message (accept or reject, [cause code]) to the AF. If the response was a reject the procedure stops here.
Step 7.
Step 7 to step12 of procedure for Inventory specified in clause 6.2.2 are performed with the following clarifications:
- In step 7, the AIOTF also includes follow on command indication in the Inventory Request message to inform the NG-RAN command delivery occurs after the inventory.
- In step 10, the NG-RAN also includes the RAN AIoT Device NGAP ID for each AIoT Device in the Inventory Report as specified in TS 38.413.
- In step 11, the AIOTF validates the results as specified in TS 33.369, and determines whether the command should be sent to an AIoT Device, e.g., by checking the Target AIoT device information. The AIOTF updates the corresponding AIoT device context in the AIOTF to include the RAN AIoT Device NGAP ID.
Step 8.
For each successful Inventory response received, the AIOTF sends Command Request message (Correlation ID, [Reader ID], NAS Command Request, [Approximate D2R message size], RAN AIoT Device NGAP ID for each AIoT Device) to the NG-RAN directly or as a NGAP AIoT information via an AMF as specified in clause 6.2.4. The NAS Command Request message includes the AIoT data. The Correlation ID is as the same as the Correlation ID generated in step 4. The RAN AIoT Device NGAP ID for each AIoT Device is used by the NG-RAN to determine the AIoT device context in NG-RAN as specified in TS 38.413.
The AIOTF uses the Command Type and Command type specific parameters received in Step 3 to determine the NAS Command Request to send to the AIoT Device, as described in clause 5.2.2.
Step 9.
The NG-RAN sends the AS R2D message (NAS Command Request) to the AIoT Device as defined in TS 38.391.
Step 10.
The AIoT Device sends the AS D2R message (NAS Command Response) to the NG-RAN as defined in TS 38.391. The NAS Command Response message may include the AIoT data.
Step 11.
The NG-RAN responds with a Command Response message (Correlation ID, Reader ID, NAS Command Response, RAN AIoT Device NGAP ID) to the AIOTF directly or as a NGAP AIoT information via an AMF as specified in clause 6.2.4. The AIOTF determines the AIoT device context by the RAN AIoT Device NGAP ID received.
Step 12.
The AIOTF reports the result of the Naiotf_AIoT_Command request to the NEF by sending the Naiotf_AIoT_Command Notify message (a list of AIoT Device(s) response information (AIoT Device ID(s), AIoT data and optionally location of each AIoT Device), AF ID, [Last Report Indication]). If multiple AIOTFs are involved in the procedure, the NEF may receive Naiotf_AIoT_Command Notify messages from multiple AIOTFs.
Based on operator policy, if the location information is requested by the AF and if the location of the reader is configured, the AIOTF uses the Reader ID reported from NG-RAN during inventory in step 7 to determine the AIoT Device Location.
When the last report is sent, the AIOTF ends the AIoT Session.
Step 13.
The NEF informs the AF of the result of the Nnef_AIoT_Command request by sending the Nnef_AIoT_Command Notify message (a list of AIoT Device(s) response information (AIoT Device ID(s), AIoT data and optionally location of each AIoT Device), AF ID, [Last Report Indication]).
6.2.4 Procedures between AIOTF and NG-RAN for Indirect Connectivity p. 30
6.2.4.1 Overview p. 30
An AIOTF and NG-RAN can use an indirect interface via an AMF as described in clause 4.2.2.3. The procedure for NGAP message delivery to NG-RAN is defined in clause 6.2.4.2 and the procedure for message delivery from NG-RAN is defined in clause 6.2.4.3.
6.2.4.2 Message delivery to NG-RAN p. 30
When the AIOTF sends commands the AMF receives an Namf_AIoT_MessageDelivery request and sends the corresponding NGAP command to NG-RAN. The additional steps used for indirect interface between AIOTF and NG-RAN are shown in Figure 6.2.4.2-1.
Figure 6.2.4.2-1: Procedure for NGAP message delivery to NG-RAN using indirect connectivity via an AMF
(⇒ copy of original 3GPP image)
(⇒ copy of original 3GPP image)
Step 1.
The AIOTF sends Namf_AIoT_MessageDelivery Request message (NGAP AIoT information, NG-RAN ID, AIOTF ID, Correlation ID, AIoT NGAP Message Type, Notification endpoint, [RAN AIoT Device NGAP ID]) to the AMF.
The AIoT NGAP Message Type identifies the NGAP message to send to NG-RAN and NGAP AIoT information is provided to NG-RAN in the NGAP message.
If the AMF receives a Notification endpoint, the AMF creates a context for the transaction and stores the NG-RAN ID, AIOTF ID, Correlation ID and Notification endpoint. The AIOTF is implicitly subscribed to Namf_AIoT_Notify events.
Step 2.
The AMF responds to the AIOTF with a result indicating whether the AMF will handle the request. If a failure is indicated by the result indication, then the procedure stops and the remaining steps are skipped.
Step 3.
The AMF sends an NGAP message (AIOTF ID, Correlation ID, NGAP AIoT information, [RAN AIoT Device NGAP ID]) to the target NG-RAN.
Step 4.
The procedure for handling NGAP messages from NG-RAN is used for route NGAP messages from NG-RAN to the AIOTF, see clause 6.2.4.3.
6.2.4.3 Message delivery to AIOTF p. 31
When the AMF receives an NGAP message from NG-RAN, for example, responses to a procedure or events like Inventory Reports, the AMF determines which AIOTF to send a Namf_AIoT_Notify to and sends the information from NG-RAN to that AIOTF. The additional steps used for indirect interface from NGAP towards AIOTF is shown in Figure 6.2.4.3-1.
Figure 6.2.4.3-1: Procedure for NG-RAN event handling using indirect connectivity via an AMF
(⇒ copy of original 3GPP image)
(⇒ copy of original 3GPP image)
Step 1.
Step 2 and step 3 are repeated for each NGAP message received from NG-RAN.
If the message received from NG-RAN is an Inventory Failure indicating an error or an AIOT Session Release Complete, then the AMF releases the context which is associated with the AIOTF ID and Correlation ID, after sending the Namf_
Before any NGAP message can be routed from NG-RAN to the AIOTF, the AMF needs routing information to be able to route the messages from NG-RAN to the AIOTF, see clause 6.2.4.2. The same context can be used route multiple NGAP messages from NG-RAN.
Step 2.
NG-RAN sends an NGAP message (AIOTF ID, Correlation ID, NGAP AIoT information, [RAN AIoT Device NGAP ID]) to an AMF. NGAP AIoT information is determine by NG-RAN depending upon the operation the NGAP message relates to.
Step 3.
AMF determines the Notification endpoint using the AIOTF ID and Correlation ID received in step 1 from NG-RAN, and then sends the Namf_AIoT_Notify message (AIoT NGAP Message Type, NGAP AIoT information) to the AIOTF.
6.2.5 AIoT Session Release Procedure p. 31
This procedure is used to release the AIoT Session between the NG-RAN and the AIOTF. The AIoT Session release procedure can be triggered by the AIOTF or the NG-RAN node and is specified in TS 38.413.
The initiation of AIoT Session release may be:
- NG-RAN-initiated e.g. if the NG-RAN detects no AIoT Devices responds to the inventory procedure or the command procedure; or
- AIOTF-initiated, e.g. if the AIOTF fails validating the results of AIOT NAS Inventory Response as specified in TS 33.369in the command procedure.
Step 1.
NG-RAN may decide to initiate the AIoT Session release procedure. NG-RAN sends AIoT Session Release request message (Correlation ID, Cause) to the AIOTF directly or as a NGAP AIoT information via an AMF as specified in clause 6.2.4.
Step 2.
If the AIOTF receives the AIoT Session Release request message or the AIOTF decides to terminate all activities related to the AIoT Session, the AIOTF sends an AIoT Session Release Command message (Correlation ID, Cause) to the NG-RAN directly or as a NGAP AIoT information via an AMF as specified in clause 6.2.4.
Step 3.
The NG-RAN node releases the AIoT Session and radio resources related to the AIoT session identified by the Correlation ID provided by the AIOTF, as specified in TS 38.300. And the NG-RAN confirms the AIoT Session Release by returning an AIoT Session Release Complete message (Correlation ID) to the AIOTF directly or as a NGAP AIoT information via an AMF as specified in clause 6.2.4. The AIOTF releases AIoT Session.
