WO2023117147A1

WO2023117147A1 - Handling of ue group subscriptions in a communication network

Info

Publication number: WO2023117147A1
Application number: PCT/EP2022/052629
Authority: WO
Inventors: Jose Miguel DOPICO SANJUAN; Juan Manuel Fernandez Galmes; Emiliano Merino Vazquez; Subrata Mukherjee
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-12-21
Filing date: 2022-02-03
Publication date: 2023-06-29

Abstract

There is provided mechanisms for handling UE group subscriptions. A method is performed by a NF node. The method comprises identifying, when a UE is to be registered with a UDM node, any UE group subscriptions. Each UE group subscription has a group identifier. The method comprises providing a request towards the UDM node for registering the UE with the UDM node. The request comprises the group identifier when the NF node identifies any UE group subscription. The request otherwise does not comprise any group identifier when the NF node fails to identify any UE group subscription.

Description

HANDLING OF UE GROUP SUBSCRIPTIONS IN A COMMUNICATION NETWORK

TECHNICAL FIELD

Embodiments presented herein relate to methods, a Network Function node, a Unified Data Management node, a Network Repository Function node, computer programs, and a computer program product for handling UE group subscriptions.

BACKGROUND

In general terms, a fifth-generation (5G) system (5GS) is a telecommunication system using the 5G New Radio (NR) air interface, or the Evolved Universal Terrestrial Radio Access (E-UTRA) air interface connected to a 5G core network (5GC). The 5GC comprises functional entities called Network Functions (NFs). System functionality is achieved by a set of NFs providing services to other authorized NFs to access their services. Each NF offers different functionalities and thereby provides different services.

Fig. 1 is a schematic diagram illustrating a communication network 10. The communication network 10 might be regarded as a public land mobile network (PLMN) and represents a reference architecture of a 5GS and comprises the following entities: an Authentication Server Function (AUSF) node 50, an Access and Mobility Management Function (AMF) node 100a, a Data Network (DN) 80, e.g. operator services, Internet access or third party services, a Network Exposure Function (NEF) node 20, a Network Repository Function (NRF) node 300, a Network Slice Selection Function (NSSF) node 15, a Policy Control Function (PCF) node 30, a Session Management Function (SMF) node 100b, a Unified Data Manager (UDM) node 200, a Unified Data Repository (UDR) node 45, a User Plane Function (UPF) node 75, an Application Function (AF) node 35, a User Equipment (UE) 85, a (Radio) Access Network ((R)AN) 70, a Network Data Analytics Function (NWDAF) node 60, a Binding Support Function (BSF) node 40, and a Charging Function (CHF) node 65. Service based interfaces are represented by the format Nxyz (e.g., Nnssf, Nnef, etc.) and point to point interfaces are represented by the format Nx (e.g. Ni, N2, etc.).

Documents 3GPP TS 23.501 “System architecture for the 5G System (5GS)” version 17.2.0 and 3GPP TS 23.502 “Procedures for the 5G System (5GS)” version 17.2.1 disclose an event exposure architecture for the 5GC, where a few network functions, such as NEF 20, UDM 200, Home Subscriber Server (HSS; not shown in Fig. 1), AMF 100a, SMF 100b, and PCF 30 implement an interface to report data to interested parties. With such an event exposure technology, a consumer can make subscriptions to certain UE-related events at an NF, and thus receives subsequent notifications related to that subscribed event.

In particular, aforementioned 3GPP TS 23.502 in clause 4.15.3.2.3 defines a mechanism whereby a subscriber of event exposure, such as NEF 20, subscribes, at UDM 200, to events related to access, mobility, and session, for a particular UE 85. The following steps are extracted therefrom:

3a. [Conditional] If the requested event (e.g. monitoring of Loss of Connectivity) requires AMF assistance, then the UDM sends the Namf_EventExposure_Subscribe to the AMF serving the requested user. The UDM sends the

Namf_EventExposure_Subscribe request to all serving AMF(s) (if subscription applies to a UE or a group of UE(s)), or all the AMF in the same PLMN as the UDM (if subscription applies to any UE).

3c. [Conditional] If the requested event (e.g. PDU Session Status) requires SMF assistance, then the UDM sends the Nsmf_EventExposure_Subscribe Request message to each SMF where at least one UE identified in step 2 has a PDU session established. The NEF notification endpoint received in step 2 is included in the message. PDU is short for Protocol Data Unit.

As it can be understood from the extracted steps, if UDM 200 receives a subscription for event exposure for a UE 85, and the event to be monitored requires assistance from either AMF 100a or SMF 100b, then UDM 200 is responsible for sending a subscription to those relevant nodes for the required events. Further, when an event exposure subscription request is received at UDM 200 for a group of UEs 85, assuming that some or many of the UEs 85 are registered, UDM 200 verifies the list of AMFs 100a and SMFs 100b that are currently serving those UEs 85, and sends subscriptions to each of them (assuming that the event requires to be reported by those NFs). The determination of the AMFs 100a and SMFs 100b that are serving the UEs 85 takes place at the time when the subscription is received at UDM 200. If at a later time, a new AMF 100a or SMF 100b starts serving a first group member UE 85 (e.g. a group member UE 85 attaches to the AMF 100a and it is the first group member UE 85 of the group to be served by the AMF 100b), the AMF 100b does not know whether the group associated with the UE 85 has any ongoing event subscriptions to be applied.

SUMMARY

An object of embodiments herein is to address the above issues relating to UE group subscriptions.

According to a first aspect there is presented a method for handling UE group subscriptions. The method is performed by a NF node. The method comprises identifying, when a UE is to be registered with a UDM node, any UE group subscriptions from the UDM node (200). Each UE group subscription has a group identifier. The method comprises providing a request towards the UDM node for registering the UE with the UDM node. The request comprises the group identifier or set of group identifiers of the identified UE group subscriptions when the NF node identifies any UE group subscription. The request otherwise does not comprise any group identifier when the NF node fails to identify any UE group subscription. In this case the request may comprise an indication that the UE does not have any UE group subscription, for example a flag or a boolean.

According to a second aspect there is presented a NF node for handling UE group subscriptions. The NF node comprises processing circuitry. The processing circuitry is configured to cause the NF node to identify, when a UE is to be registered with a UDM node, any UE group subscriptions from the UDM node (200). Each UE group subscription has a group identifier. The processing circuitry is configured to cause the NF node to provide a request towards the UDM node for registering the UE with the UDM node. The request comprises the group identifier or set of group identifiers of the identified UE group subscriptions when the NF node identifies any UE group subscription. The request otherwise does not comprise any group identifier when the NF node fails to identify any UE group subscription.

According to a third aspect there is presented a computer program for handling UE group subscriptions, the computer program comprising computer program code which, when run on processing circuitry of an NF node, causes the NF node to perform a method according to the first aspect.

According to a fourth aspect there is presented a method for handling UE group subscriptions. The method is performed by a UDM node. The method comprises obtaining a request from a NF node for registering a UE with the UDM node. The request comprises a group identifier or a set of group identifiers pertaining to one or more UE group subscriptions at the NF node when the NF node has identified any UE group subscription. The request otherwise does not comprise any group identifier when the NF node has failed to identify any UE group subscription. The method comprises identifying that the UE is associated with at least one UE group subscription not indicated in the request. The method comprises providing a message towards the NF node. The message comprises an indicator of each said at least one UE group subscription not indicated in the request.

According to a fifth aspect there is presented a UDM node for handling UE group subscriptions. The UDM node comprises processing circuitry. The processing circuitry is configured to cause the UDM node to obtain a request from a NF node for registering a UE with the UDM node. The request comprises a group identifier or a set of group identifiers pertaining to one or more UE group subscriptions at the NF node when the NF node has identified any UE group subscription. The request otherwise does not comprise any group identifier when the NF node has failed to identify any UE group subscription. The processing circuitry is configured to cause the UDM node to identify that the UE is associated with at least one UE group subscription not indicated in the request. The processing circuitry is configured to cause the UDM node to provide a message towards the NF node. The message comprises an indicator of each said at least one UE group subscription not indicated in the request.

According to a sixth aspect there is presented a computer program for handling UE group subscriptions, the computer program comprising computer program code which, when run on processing circuitry of a UDM node, causes the UDM node to perform a method according to the fourth aspect.

According to a seventh aspect there is presented a method for handling UE group subscriptions. The method is performed by a NRF node. The method comprises registering, with a UDM node, a profile of a NF node for UE group subscriptions. The profile comprises an address of the UDM node. The method comprises storing the profile.

According to an eighth aspect there is presented a NRF node for handling UE group subscriptions. The NRF node comprises processing circuitry. The processing circuitry is configured to cause the NRF node to register, with a UDM node, a profile of a NF node for UE group subscriptions. The profile comprises an address of the UDM node. The processing circuitry is configured to cause the NRF node to store the profile.

According to a tenth aspect there is presented a computer program for handling UE group subscriptions, the computer program comprising computer program code which, when run on processing circuitry of an NRF node, causes the NRF node to perform a method according to the seventh aspect.

According to an eleventh aspect there is presented a computer program product comprising a computer program according to at least one of the third aspect, the sixth aspect, and the tenth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium can be a non- transitory computer readable storage medium.

Advantageously, these aspects allow NFs to retrieve any unknown event exposure information associated to group identifiers (i.e., group of UEs).

Advantageously, these aspects therefore enable NFs to retrieve the information when the group is served for the first time, that is, when the first UE for the group is served and the NF does not yet have any event exposure information for the group in its local storage.

Advantageously, these aspects therefore enable NFs to synchronize with the UDM (or regain group information consistency) at any moment by removing its local copy of the group information (e.g. flush the cache in the NF) and notifying the UDM about any possible unknown group identities so that the UDM can send a list of any currently active subscription for the group. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, module, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic diagram illustrating a communication network according to an example;

Fig. 2 is a signalling diagram according to an example;

Figs. 3, 4, and 5 are flowcharts of methods according to embodiments;

Fig. 6 is a signalling diagram according to an embodiment;

Fig. 7 is a schematic diagram showing functional units of an NF node according to an embodiment;

Fig. 8 is a schematic diagram showing functional modules of an NF node according to an embodiment;

Fig. 9 is a schematic diagram showing functional units of a UDM node according to an embodiment;

Fig. 10 is a schematic diagram showing functional modules of a UDM node according to an embodiment; Fig. n is a schematic diagram showing functional units of an NRF node according to an embodiment;

Fig. 12 is a schematic diagram showing functional modules of an NRF node according to an embodiment; and

Fig. 13 shows one example of a computer program product comprising computer readable means according to an embodiment.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

Further aspects of the above identified issues relating to UE group subscriptions will be highlighted next with reference to the signalling diagram of Fig. 2.

Si: Upon subscription from AF, NEF subscribes to UDM for a group of UEs.

S2: UDM checks for any group member UEs and determines that, at that moment, AMF-i and AMF-2 at least are serving one group member UE. That is, there is at least one UE belonging to the group.

S3: UDM sends the subscription to AMF-i, so that the event monitoring is started for those UEs.

S4: UDM repeats steps S2 and S3 for AMF-2, to monitor served UEs belonging to the group in AMF-2.

S5: Group member UE registers with AMF-3.

S6: AMF-3 registers towards UDM. S7: UDM accepts the registration.

S8: After registration is accepted, AMF retrieves access and mobility subscription data (which includes the list of groups to which the UE belongs to) and stores the data as part of the UE context.

S9: Group member UE changes to a new location.

S10: Since UDM did not subscribe to AMF-3 because there was not any UE registered in AMF-3 when the subscription from NEF occurred, AMF-3 does not report the event detected.

When the AMF fetches the Access and Mobility data (AM-data) in step S8, the AMF receives the group identifiers associated with the UE, i.e. the group identifiers to which the UE belongs to. Hence, when AMF-3 serves for the first time a group member UE for a group, AMF-3 is not aware of not having the event subscriptions applicable for the group, and neither is UDM. The AMF can only indicate during registration whether the UE has individual subscriptions to events, but it does not know the groups associated to the UE (if any) at the time of registration, Therefore, UDM does not send any subscriptions associated with the UE since it does not know whether they are missing in the AMF yet. This implies that future UEs associated to the same group of UEs will not be monitored with the events subscribed for the group. It is one purpose of the present disclosure to address this issue.

The embodiments disclosed herein in particular relate to mechanisms for handling UE group subscriptions. In order to obtain such mechanisms there is provided an NF node 100a, 100b, a method performed by the NF node 100a, 100b, a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the NF node 100a, 100b, causes the NF node 100a, 100b to perform the method. In order to obtain such mechanisms there is further provided a UDM node 200, a method performed by the UDM node 200, and a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the UDM node 200, causes the UDM node 200 to perform the method. In order to obtain such mechanisms there is further provided an NRF node 300, a method performed by the NRF node 300, and a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the NRF node 300, causes the NRF node 300 to perform the method.

The embodiments disclosed herein enable AMF to inform UDM about a potential loss of event exposure subscriptions related to groups of UEs. This is since UDM only subscribes to those AMFs which are at least serving one group member UE at the time of subscription from NEF/AF. The embodiments disclosed herein further provide a mechanism whereby AMF triggers a re-synchronization of event exposure information towards UDM.

The embodiments disclosed herein are applicable for AMF during initial registration procedure. The embodiments disclosed herein could are also applicable for SMF during a PDU session establishment procedure (where SMF also registers in UDM).

Reference is now made to Fig. 3 illustrating a method for handling UE group subscriptions as performed by the NF node 100a, 100b according to an embodiment.

S102: The NF node 100a, 100b identifies, when a UE, 85 is to be registered with a UDM node 200, any UE group subscriptions. Each UE group subscription has a group identifier. It is possible that no subscriptions are identified. There can be multiple subscriptions to the same group identifier, e.g. from different AF nodes 100a towards the same group of UEs 85.

S104: The NF node 100a, 100b provides a request towards the UDM node 200 for registering the UE 85 with the UDM node 200. The request comprises the group identifier when the NF node 100a, 100b identifies any UE group subscription. The request otherwise does not comprise any group identifier when the NF node 100a, 100b fails to identify any UE group subscription. That is, the group identifier is not provided to the UDM node 200 when the NF 100a, 100b is not aware of any UE group subscription for any UE 85. In this case the request may comprise an indication that the UE does not have any UE group subscription, for example a flag or a boolean.

Thereby, when an NF node 100a, 100b registers the UE 85 with the UDM node 200, the NF node 100a, 100b first checks whether any UE group subscription exists. If no UE group subscriptions exist, the NF node 100a, 100b indicates so in the UE registration. If there is at least one UE group subscription found in the NF node 100a, 100b, the NF node 100a, 100b includes the group identifier(s) for which the NF node 100a, 100b knows there are subscriptions.

Embodiments relating to further details of handling UE group subscriptions as performed by the NF node 100a, 100b will now be disclosed.

There could be different examples of NF nodes 100a, 100b. In some examples, the NF node 100a, 100b is an AMF node 100a, or an SMF node 100b.

In some aspects, the NF node 100a, 100b receives a message from the UDM node 200 identifying any missing groups. In particular, in some embodiments, the NF node 100a, 100b is configured to perform (optional) step S106:

S106: The NF node 100a, 100b obtains a message from the UDM node 200, wherein the message comprises an indicator of each at least one further UE group subscription which the UE 85 is associated with.

In this respect, the message might be preceded by an OK message received from the UDM node 200 in response to having sent the request in step S104.

There could be different indicators received in S106. In some embodiments, the indicator is an event exposure subscription for the at least one further UE group subscription.

As disclosed above, the request does not comprise any group identifier when the NF node 100a, 100b fails to identify any UE group subscription associated with the UE 85. Hence, in some embodiments, zero UE group subscriptions are identified by the NF node 100a, 100b.

In some embodiments, when the NF node 100a, 100b has not identified any UE group subscriptions, the request comprises an information element indicating that the NF node 100a, 100b does not have any event exposure UE group subscription applicable to the UE 85. This information element could be a Boolean information element set to “True”, or “Not Default”, or the like.

In some embodiments, when the NF node 100a, 100b has identified at least one UE group subscription, the request comprises an information element indicating that the NF node 100a, 100b has at least one event exposure UE group subscription. This information element could be a Boolean information element set to “False”, or “Default”, or the like.

In some embodiments, when the NF node 100a, 100b has identified at least one UE group subscription, the request comprises an array information element indicating all group identifiers for which the NF node 100a, 100b already has event exposure UE group subscriptions for which the NF node 100a, 100b already has event exposure subscriptions.

There could be different examples of services for which the UE 85 is registered. In some examples, the UE 85 is registered for a UE Context Management Service (UECM). There could be different examples of UE group subscriptions. In some examples, the UE group subscriptions are subscriptions for event exposure for groups of UEs 85. There could be different examples of events. In some examples, the events are related to access, mobility, and sessions, for the groups of UEs 85.

Reference is now made to Fig. 4 illustrating a method for handling UE group subscriptions as performed by the UDM node 200 according to an embodiment.

S204: The UDM node 200 obtains a request from the NF node 100a, 100b for registering a UE 85 with the UDM node 200. The request comprises a group identifier when the NF node 100a, 100b has identified any identified UE group subscription. The request otherwise does not comprise any group identifier when the NF node 100a, 100b has failed to identify any UE group subscription.

S206: The UDM node 200 identifies that the UE 85 is associated with at least one UE group subscription not indicated in the request.

S210: The UDM node 200 provides a message towards the NF node 100a, 100b. The message comprises an indicator of each at least one UE group subscription not indicated in the request.

In this respect, the message in S210 might be preceded by an OK message transmitted from the UDM node 200 in response to the request received in step S204. Thereby, when the UDM node 200 receives an indication from an NF node 100a, 100b stating that no UE group subscriptions exist, the UDM node 200 retrieves any groups associated with the UE 85 being registered, and sends the subscriptions (if any) of those related group identifiers to the NF node 100a, 100b. Further, if the UDM node 200 receives any group identifier(s) for which NF node 100a, 100b has subscriptions, the UDM node 200 performs a check against the group(s) associated with the UE 85. If there is at least a group associated with the UE 85 which was not received from the NF node 100a, 100b (i.e. the NF node 100a, 100b is missing subscriptions for the group, if any), the UDM node 200 checks for event subscriptions for the missing group(s). If subscriptions are found for the group(s), the UDM node 2oosends the subscriptions of those related group identifiers to the NF node 100a, 100b.

Embodiments relating to further details of handling UE group subscriptions as performed by the UDM node 200 will now be disclosed.

There could be different ways for the UDM node 200 to identify that the UE 85 is associated with at least one UE group subscription not indicated in the request. For example, the UDM node 200 might perform a check against any groups associated with the 85 and check event subscriptions for any missing groups. In particular, in some embodiments the UDM node 200 has access to a list of UE group subscriptions which the UE 85 is associated with, and the UDM node 200 is configured to perform (optional) step 8206a as part of identifying that the UE 85 is associated with at least one UE group subscription not indicated in the request:

8206a: The UDM node 200 identifies any UE group subscriptions included in the list but not associated with any group identifier obtained in the request.

In some aspects, the UDM node 200 determines that new group event subscriptions have to be created. That is, in some embodiments, the UDM node 200 is configured to perform (optional) step S208:

S208: The UDM node 200 determines that each of the at least one further UE group subscription is to be created by the NF node 100a, 100b. In some aspects, the UDM node 200 registers with the NRF node 300 the NF profile, optionally including a notification about unknown group event subscriptions. In particular, in some embodiments, the UDM node 200 is configured to perform (optional) step S202:

S202: The UDM node 200 registers, with an NRF node 300, a profile of the NF node 100a, 100b for UE group subscriptions. The profile comprises an address of the UDM node 200.

As disclosed above, in some examples, the indicator is an event exposure subscription for the at least one further UE group subscription.

As disclosed above, the request does not comprise any group identifier when the NF node 100a, 100b fails to identify any UE group subscription associated with the UE 85. Hence, in some embodiments, the request in S204 comprises zero UE group subscriptions.

As disclosed above, in some embodiments, the request comprises an information element indicating that the NF node 100a, 100b does not have any event exposure UE group subscription applicable to the UE 85. As disclosed above, this information element could be a Boolean information element set to “True”, or “Not Default”, or the like.

As disclosed above, in some embodiments, the request comprises an information element indicating that the NF node 100a, 100b has at least one event exposure UE group subscription. As disclosed above, this information element could be a Boolean information element set to “False”, or “Default”, or the like.

As disclosed above, in some embodiments, the request comprises an array information element indicating all group identifiers for which the NF node 100a, 100b already has event exposure UE group subscriptions for which the NF node 100a, 100b already has event exposure subscriptions.

Reference is now made to Fig. 5 illustrating a method for handling UE group subscriptions as performed by the NRF node 300 according to an embodiment. S302: The NRF node 300 registers, with the UDM node 200, a profile of the NF node 100a, 100b for UE group subscriptions. The profile comprises an address of the UDM node 200.

S304: The NRF node 300 stores the profile.

Embodiments relating to further details of handling UE group subscriptions as performed by the NRF node 300 will now be disclosed.

In some aspects, NRF receives a discovery request from NF and responds with those UDM instances that have included the notification address for the default notification type in the NF profile registered in NRF. Hence, in some embodiments, the NRF node 300 is configured to perform (optional) steps S306 and S308:

S306: The NRF node 300 obtains a discovery request from the NF node 100a, 100b.

S308: The NRF node 300 provides a response to the discovery request. The response comprises the address of the UDM node 200.

One particular embodiment for handling UE group subscriptions based on at least some of the above disclosed embodiments will now be disclosed in detail with reference to the signalling diagram of Fig. 6.

Step 1: Preparations are performed, including the following: Upon an event subscription request received from an Application Function (AF), the NEF authorizes the request and subscribes in the UDM for a group of UEs. Then the UDM subscribes in the AMF(s) serving the UEs of the group to start monitoring of events detected by the AMF. This includes a group-based event exposure subscription being made by NEF with UDM, and subsequent creation of event subscriptions for the group by being made by UDM with AMF-1 and AMF-2.

Step 2: A new group member UE is registered in AMF-3.

Step 3: AMF-3 checks internally whether there are existing group-based event subscriptions, i.e. any UE group subscriptions created previously by UDM with AMF- 3- Scenario 1: AMF-3 does not have event subscriptions for any group. Steps 5-9 are executed.

Steps 5-7: AMF-3 does not find any group event subscription and registers with UDM for the new group member UE, including the indication that there are not any UE group subscriptions registered with AMF-3.

Step 8: Based on the explicit indication that no UE group subscriptions are known to AMF-3, UDM checks whether or not the UE being registered belongs to any group and whether or not there are existing event subscriptions for any of the groups associated with the UE. If so, UDM determines that group event subscriptions have to be registered in AMF-3.

Step 9: UDM registers for AMF-3 the event subscriptions for the groups the UE belongs to, sending one request per group event subscription.

Scenario 2: AMF-3 has at least a UE group subscription for the UE.

Alternative 1: AMF indicates the groups for which there are known event subscriptions when registering with UDM. Steps 11-14 are executed.

Steps 11-12: AMF-3 finds at least a group event subscription and registers with UDM for the new group member UE indicating the group identifiers for which there are event subscriptions in AMF-3.

Step 13: Based on the explicit indication about groups for which there are event subscriptions known to AMF-3, UDM checks whether the UE being registered belongs to any group and whether there are existing event subscriptions for any of the groups associated to the UE. If there are event subscriptions for any of the groups associated with the UE that are unknown to AMF-3, UDM determines that the missing event subscriptions for those groups have to be registered in AMF-3.

Step 14: UDM registers for AMF-3 the event subscriptions for the groups the UE belongs to that are missing in AMF-3, sending one request per group event subscription.

Scenario 2: AMF-3 has at least a UE group subscription for the UE. Alternative 2: AMF notifies UDM after retrieving UE subscription data including the groups the UE belongs to. Steps 16-29 or steps 16-26 and 30-31 are executed.

Steps 16-17: UDM supports to be notified (i.e. UDM is a default notification endpoint) about lack of information of group event subscriptions and hence a default notification address for this new default notification type is included in the NF profile to be registered in the NRF. UDM registers with the NRF the NF profile including the new default notification type about unknown group event subscriptions.

Step 18: NRF stores the NF profile of UDM, including the new notification type.

Registration in NRF including the new notification type is shown in steps 16-18 in Fig. 6, though the registration might be performed previously (e.g. when an instance of UDM comes in service in the network).

Steps 19-21: After the UE is successfully registered, without including the new indications described in steps 6 and 12, AMF-3 retrieves UE subscription data (Access and Mobility Subscription Data), which include the groups the UE belongs to.

Step 22: AMF-3 checks internally whether there are existing group-based event subscriptions for the groups the UE belongs to. If there are not any event subscriptions for any of those groups (i.e. it is the first UE registering in AMF-3 for any of those groups), AMF-3 determines to notify UDM about possibly unknown event subscriptions for the related groups.

Step 23: AMF-3 discovers an instance of UDM supporting the new default notification type by sending a discovery request to NRF.

Step 24: The NRF provides in the discovery response an indication of instances of the UDM that have included the notification address for the new default notification type in the NF profile registered with the NRF.

Step 25: AMF-3 notifies UDM about unknown event subscriptions for the corresponding groups.

Step 26: UDM checks whether or not there are existing event subscriptions for any of the groups received in the notification from AMF-3. Step 27-28: If there are event subscriptions for any of the groups received in the notification, UDM provides a 202 Accepted response to indicate that AMF should wait for event subscription requests.

Step 29: UDM registers the event subscriptions for the groups that are missing in AMF-3, sending one request per group event subscription.

Step 30-31: If there are not any event subscriptions for the groups received in the notification, UDM provides a 204 No content response so that AMF-3 becomes aware that no group event subscriptions are missing and avoids subsequent notifications towards UDM for those groups.

The new information in steps 6 and 12 could be included as information elements (IES) in aforementioned 3GPP TS 29.503, such as in Table 6.2.6.2.2-1 in 3GPP TS ²9-5O3, according to Table 1.

Table 1: Examples of information elements

(a): This IE might be absent on communication over the Nudr interface and maybe present on communication over the Nudm interface. This IE is used by UDM to restore any possible ongoing subscriptions for the groups associated to the UE. When present, this IE indicates whether AMF does not have event exposure UE group subscriptions applicable to the UE, regardless of the groups the UE might belong to. If set to “True”, no event exposure UE group subscriptions can be applied by AMF to the UE if the UE is a group member, i.e. UDM is to send all subscriptions (if any) for all groups associated with the UE (if any). If set to “False” (default), event exposure UE group subscription(s) maybe required for the UE if the UE is a group member, i.e. UDM should send the subscriptions (if any) for those groups not included in eeSubscriptionsGroupList. (b): This IE might be absent on communication over the Nudr interface and might be present on communication over the Nudm interface. This IE can be used by UDM to restore any possible ongoing subscriptions for the groups associated to the UE. When present, this IE might indicate the list of internal group identifiers for which the AMF already has event exposure subscriptions. This IE might be present if noEeGroupSubscriptionlnd is absent, or false, but otherwise, it might be absent.

Fig. 7 schematically illustrates, in terms of a number of functional units, the components of an NF node 100a, 100b according to an embodiment. Processing circuitry no is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310a (as in Fig. 13), e.g. in the form of a storage medium 130. The processing circuitry 210 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry no is configured to cause the NF node 100a, 100b to perform a set of operations, or steps, as disclosed above. For example, the storage medium 130 may store the set of operations, and the processing circuitry 110 maybe configured to retrieve the set of operations from the storage medium 130 to cause the NF node 100a, 100b to perform the set of operations. The set of operations maybe provided as a set of executable instructions. Thus the processing circuitry 110 is thereby arranged to execute methods as herein disclosed.

The storage medium 130 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The NF node 100a, 100b may further comprise a communications interface 220 for communications with other entities, functions, nodes, and devices, as in the communication network 10 of Fig. 1. As such the communications interface 120 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry no controls the general operation of the NF node 100a, 100b e.g. by sending data and control signals to the communications interface 220 and the storage medium 130, by receiving data and reports from the communications interface 120, and by retrieving data and instructions from the storage medium 130. Other components, as well as the related functionality, of the NF node 100a, 100b are omitted in order not to obscure the concepts presented herein.

Fig. 8 schematically illustrates, in terms of a number of functional modules, the components of an NF node 100a, 100b according to an embodiment. The NF node 100a, 100b of Fig. 8 comprises a number of functional modules; an identify module 110a configured to perform step S102 and a provide module 210b configured to perform step S104. The NF node 100a, 100b of Fig. 8 may further comprise a number of optional functional modules, such as an obtain module 110c configured to perform step S106. In general terms, each functional module noa:noc maybe implemented in hardware or in software. Preferably, one or more or all functional modules 110a: 110c maybe implemented by the processing circuitry no, possibly in cooperation with the communications interface 220 and the storage medium 130. The processing circuitry no may thus be arranged to from the storage medium 130 fetch instructions as provided by a functional module 110a: 110c and to execute these instructions, thereby performing any steps of the NF node 100a, 100b as disclosed herein.

Fig. 9 schematically illustrates, in terms of a number of functional units, the components of a UDM node 200 according to an embodiment. Processing circuitry 210 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310b (as in Fig. 13), e.g. in the form of a storage medium 230. The processing circuitry 210 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry 310 is configured to cause the UDM node 200 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 230 may store the set of operations, and the processing circuitry 210 maybe configured to retrieve the set of operations from the storage medium 230 to cause the UDM node 200 to perform the set of operations. The set of operations maybe provided as a set of executable instructions. Thus the processing circuitry 210 is thereby arranged to execute methods as herein disclosed.

The storage medium 230 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The UDM node 200 may further comprise a communications interface 220 for communications with other entities, functions, nodes, and devices, as in the communication network 10 of Fig. 1. As such the communications interface 220 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry 310 controls the general operation of the UDM node 200 e.g. by sending data and control signals to the communications interface 320 and the storage medium 230, by receiving data and reports from the communications interface 220, and by retrieving data and instructions from the storage medium 230. Other components, as well as the related functionality, of the UDM node 200 are omitted in order not to obscure the concepts presented herein.

Fig. 10 schematically illustrates, in terms of a number of functional modules, the components of a UDM node 200 according to an embodiment. The UDM node 200 of Fig. 10 comprises a number of functional modules; an obtain module 210b configured to perform step S204, an identify module 210c configured to perform step S206, and a provide module 2iof configured to perform step S210. The UDM node 200 of Fig. 10 may further comprise a number of optional functional modules, such as any of a register module 210a configured to perform step S202, an identify module 2iod configured to perform step 8206a, and a determine module 2ioe configured to perform step S208. In general terms, each functional module 2ioa:2iof maybe implemented in hardware or in software. Preferably, one or more or all functional modules 210a: 2iof maybe implemented by the processing circuitry 210, possibly in cooperation with the communications interface 220 and the storage medium 230. The processing circuitry 210 may thus be arranged to from the storage medium 230 fetch instructions as provided by a functional module 2ioa:2iof and to execute these instructions, thereby performing any steps of the UDM node 200 as disclosed herein. Fig. 11 schematically illustrates, in terms of a number of functional units, the components of an NRF node 300 according to an embodiment. Processing circuitry 310 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310c (as in Fig. 13), e.g. in the form of a storage medium 330. The processing circuitry 310 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry 310 is configured to cause the NRF node 300 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 330 may store the set of operations, and the processing circuitry 310 maybe configured to retrieve the set of operations from the storage medium 330 to cause the NRF node 300 to perform the set of operations. The set of operations maybe provided as a set of executable instructions. Thus the processing circuitry 310 is thereby arranged to execute methods as herein disclosed.

The storage medium 330 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

The NRF node 300 may further comprise a communications interface 320 for communications with other entities, functions, nodes, and devices, as in the communication network 10 of Fig. 1. As such the communications interface 420 may comprise one or more transmitters and receivers, comprising analogue and digital components.

The processing circuitry 310 controls the general operation of the NRF node 300 e.g. by sending data and control signals to the communications interface 320 and the storage medium 330, by receiving data and reports from the communications interface 320, and by retrieving data and instructions from the storage medium 330. Other components, as well as the related functionality, of the NRF node 300 are omitted in order not to obscure the concepts presented herein.

Fig. 12 schematically illustrates, in terms of a number of functional modules, the components of an NRF node 300 according to an embodiment. The NRF node 300 of Fig. 12 comprises a number of functional modules; a register module 310a configured to perform step S302, and a store module 310b configured to perform step S304. The NRF node 300 of Fig. 12 may further comprise a number of optional functional modules, such as any of an obtain module 310c configured to perform step S306, and a provide module 3iod configured to perform step S308. In general terms, each functional module 3ioa:3iod maybe implemented in hardware or in software. Preferably, one or more or all functional modules 3ioa:3iod maybe implemented by the processing circuitry 310, possibly in cooperation with the communications interface 320 and the storage medium 330. The processing circuitry 310 may thus be arranged to from the storage medium 330 fetch instructions as provided by a functional module 3ioa:3iod and to execute these instructions, thereby performing any steps of the NRF node 300 as disclosed herein.

Any of the NF node 100a, 100b, the UDM node 200, and the NRF node 300 maybe provided as a standalone device or as a part of at least one further device. For example, the NF node 100a, 100b, the UDM node 200, and the NRF node 300 may be provided in one or more nodes of the core network, as in the communication network 10 of Fig. 1. Alternatively, functionality of the NF node 100a, 100b maybe distributed between at least two devices, or nodes. A first portion of the instructions performed by each of the NF node 100a, 100b, the UDM node 200, and the NRF node 300 maybe executed in a respective first device, and a second portion of the of the instructions performed by each of the NF node 100a, 100b, the UDM node 200, and the NRF node 300 maybe executed in a respective second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the NF node 100a, 100b, the UDM node 200, and/or the NRF node 300 maybe executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by an NF node 100a, 100b, a UDM node 200, and an NRF node 300 residing in a cloud computational environment. Therefore, although a single processing circuitry no, 210, 310 is illustrated in Figs. 7, 9, and 11 the processing circuitry no, 210, 310 maybe distributed among a plurality of devices, or nodes. The same applies to the functional modules noa:iioc, 2ioa:2iof, 3ioa:3iod of Figs. 8, 10, 12 and the computer programs 1320a, 1320b, 1320c of Fig. 13. Fig. 13 shows one example of a computer program product 1310a, 1310b, 1310c comprising computer readable means 1330. On this computer readable means 1330, a computer program 1320a can be stored, which computer program 1320a can cause the processing circuitry 210 and thereto operatively coupled entities and devices, such as the communications interface 220 and the storage medium 230, to execute methods according to embodiments described herein. The computer program 1320a and/or computer program product 1310a may thus provide means for performing any steps of the NF node 100a, 100b as herein disclosed. On this computer readable means 1330, a computer program 1320b can be stored, which computer program 1320b can cause the processing circuitry 310 and thereto operatively coupled entities and devices, such as the communications interface 320 and the storage medium 330, to execute methods according to embodiments described herein. The computer program 1320b and/or computer program product 1310b may thus provide means for performing any steps of the UDM node 200 as herein disclosed. On this computer readable means 1330, a computer program 1320c can be stored, which computer program 1320c can cause the processing circuitry 410 and thereto operatively coupled entities and devices, such as the communications interface 420 and the storage medium 430, to execute methods according to embodiments described herein. The computer program 1320c and/or computer program product 1310c may thus provide means for performing any steps of the NRF node 300 as herein disclosed.

In the example of Fig. 13, the computer program product 1310a, 1310b, 1310c is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1310a, 1310b, 1310c could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 1320a, 1320b, 1320c is here schematically shown as a track on the depicted optical disk, the computer program 1320a, 1320b, 1320c can be stored in any way which is suitable for the computer program product 1310a, 1310b, 1310c. The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

25 CLAIMS

1. A method for handling UE group subscriptions, the method being performed by a Network Function, NF, node (100a, 100b), the method comprising: identifying (S102), when a User Equipment, UE, (85) is to be registered with a Unified Data Management, UDM, node (200), any UE group subscriptions from the UDM node (200), wherein each UE group subscription has a group identifier; and providing (S104) a request towards the UDM node (200) for registering the UE (85) with the UDM node (200), wherein the request comprises the group identifier or set of group identifiers of the identified UE group subscriptions when the NF node (100a, 100b) identifies any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) fails to identify any UE group subscription.

2. The method according to claim 1, wherein the method further comprises: obtaining (S106) a message from the UDM node (200), wherein the message comprises an indicator of each at least one further UE group subscription which the UE (85) is associated with.

3. The method according to claim 2, wherein the indicator is an event exposure subscription for said at least one further UE group subscription.

4. The method according to claim 1, wherein zero UE group subscriptions are identified.

5. The method according to claim 1, wherein, when the NF node (100a, 100b) has not identified any UE group subscriptions, the request comprises an information element indicating that the NF node (100a, 100b) does not have any event exposure UE group subscription applicable to the UE (85).

6. The method according to claim 1, wherein, when the NF node (100a, 100b) has identified at least one UE group subscription, the request comprises an information element indicating that the NF node (100a, 100b) has at least one event exposure UE group subscription.

7. The method according to claim 1, wherein, when the NF node (100a, 100b) has identified at least one UE group subscription, the request comprises an array information element indicating all group identifiers for which the NF node (100a, 100b) already has event exposure UE group subscriptions for which the NF node (100a, 100b) already has event exposure subscriptions.

8. The method according to claim 1, wherein the UE (85) is registered for a UE Context Management Service, UECM.

9. The method according to claim 1, wherein the UE group subscriptions are subscriptions for event exposure for groups of UEs (85).

10. The method according to claim 9, wherein the events are related to access, mobility, and sessions, for the groups of UEs (85).

11. The method according to claim 1, wherein the NF node (100a, 100b) is an AMF node (100a), or an SMF node (100b).

12. A method for handling UE group subscriptions, the method being performed by a Unified Data Management, UDM, node (200), the method comprising: obtaining (S204) a request from a Network Function, NF, node (100a, 100b) for registering a User Equipment, UE (85), with the UDM node (200), wherein the request comprises a group identifier or a set of group identifiers pertaining to one or more UE group subscriptions at the NF node when the NF node (100a, 100b) has identified any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) has failed to identify any UE group subscription; identifying (S206) that the UE (85) is associated with at least one UE group subscription not indicated in the request; and providing (S210) a message towards the NF node (100a, 100b), wherein the message comprises an indicator of each said at least one UE group subscription not indicated in the request.

13. The method according to claim 12, wherein the UDM node (200) has access to a list of UE group subscriptions which the UE (85) is associated with, and wherein identifying that the UE (85) is associated with at least one UE group subscription not indicated in the request comprises: identifying (8206a) any UE group subscriptions included in the list but not associated with any group identifier obtained in the request.

14. The method according to claim 12, wherein the method further comprises: determining (S208) that each said at least one further UE group subscription is to be created by the NF node (100a, 100b).

15. The method according to claim 12, wherein the indicator is an event exposure subscription for said at least one further UE group subscription.

16. The method according to claim 12, wherein the method further comprises: registering (S202), with a Network Repository Function, NRF, node (300), a profile of the NF node (100a, 100b) for UE group subscriptions, wherein the profile comprises an address of the UDM node (200).

17. The method according to claim 12, wherein the request comprises zero UE group subscriptions.

18. The method according to claim 12, wherein the request comprises an information element indicating that the NF node (100a, 100b) does not have any event exposure UE group subscription applicable to the UE (85).

19. The method according to claim 12, wherein the request comprises an information element indicating that the NF node (100a, 100b) has at least one event exposure UE group subscription.

20. The method according to claim 12, wherein the request comprises an array information element indicating all group identifiers for which the NF node (100a, 100b) already has event exposure UE group subscriptions for which the NF node (100a, 100b) already has event exposure subscriptions.

21. A method for handling UE group subscriptions, the method being performed by a Network Repository Function, NRF, node (300), the method comprising: 28 registering (S302), with a Unified Data Management, UDM, node (200), a profile of a Network Function, NF, node (100a, 100b) for UE group subscriptions, wherein the profile comprises an address of the UDM node (200); and storing (S304) the profile.

22. The method according to claim 21, wherein the method further comprises: obtaining (S306) a discovery request from the NF node (100a, 100b); and providing (S308) a response to the discovery request, wherein the response comprises the address of the UDM node (200).

23. A Network Function, NF, node (100a, 100b) for handling UE group subscriptions, the NF node (100a, 100b) comprising processing circuitry (no), the processing circuitry being configured to cause the NF node (100a, 100b) to: identify, when a User Equipment, UE, (85) is to be registered with a Unified Data Management, UDM, node (200), any UE group subscriptions from the UDM node (200), wherein each UE group subscription has a group identifier; and provide a request towards the UDM node (200) for registering the UE (85) with the UDM node (200), wherein the request comprises the group identifier or set of group identifiers of the identified UE group subscriptions when the NF node (100a, 100b) identifies any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) fails to identify any UE group subscription.

24. The NF node (100a, 100b) according to claim 23, wherein the processing circuitry (no) further is configured to cause the NF node (100a, 100b) to perform the method according to any of claims 2 to 11.

25. A Unified Data Management, UDM, node (200) for handling UE group subscriptions, the UDM node (200) comprising processing circuitry (210), the processing circuitry being configured to cause the UDM node (200) to: obtain a request from a Network Function, NF, node (100a, 100b) for registering a User Equipment, UE (85), with the UDM node (200), wherein the 29 request comprises a group identifier or a set of group identifiers pertaining to one or more UE group subscriptions at the NF node when the NF node (100a, 100b) has identified any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) has failed to identify any UE group subscription; identify that the UE (85) is associated with at least one UE group subscription not indicated in the request; and provide a message towards the NF node (100a, 100b), wherein the message comprises an indicator of each said at least one UE group subscription not indicated in the request.

26. The UDM node (200) according to claim 25, wherein the processing circuitry (210) further is configured to cause the UDM node (200) to perform the method according to any of claims 13 to 20.

27. A Network Repository Function, NRF, node (300) for handling UE group subscriptions, the NRF node (300) comprising processing circuitry (310), the processing circuitry being configured to cause the NRF node (300) to: register, with a Unified Data Management, UDM, node (200), a profile of a Network Function, NF, node (100a, 100b) for UE group subscriptions, wherein the profile comprises an address of the UDM node (200); and store the profile.

28. The NRF node (300) according to claim 27, wherein the processing circuitry (310) further is configured to cause the NRF node (300) to perform the method according to claim 22.

29. A computer program (1320a) for handling UE group subscriptions, the computer program comprising computer code which, when run on processing circuitry (no) of a Network Function, NF, node (100a, 100b), causes the NF node (100a, 100b) to: 30 identify (S102), when a User Equipment, UE, (85) is to be registered with a Unified Data Management, UDM, node (200), any UE group subscriptions, wherein each UE group subscription has a group identifier; and provide (S104) a request towards the UDM node (200) for registering the UE (85) with the UDM node (200), wherein the request comprises the group identifier when the NF node (100a, 100b) identifies any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) fails to identify any UE group subscription.

30. A computer program (1320b) for handling UE group subscriptions, the computer program comprising computer code which, when run on processing circuitry (210) of a Unified Data Management, UDM, node (200), causes the UDM node (200) to: obtain (S204) a request from a Network Function, NF, node (100a, 100b) for registering a User Equipment, UE (85), with the UDM node (200), wherein the request comprises a group identifier when the NF node (100a, 100b) has identified any UE group subscription, and wherein the request otherwise does not comprise any group identifier when the NF node (100a, 100b) has failed to identify any UE group subscription; identify (S206) that the UE (85) is associated with at least one UE group subscription not indicated in the request; and provide (S210) a message towards the NF node (100a, 100b), wherein the message comprises an indicator of each said at least one UE group subscription not indicated in the request.

31. A computer program (1320c) for handling UE group subscriptions, the computer program comprising computer code which, when run on processing circuitry (310) of a Network Repository Function, NRF, node (300), causes NRF node (300) to: register (S302), with a Unified Data Management, UDM, node (200), a profile of a Network Function, NF, node (100a, 100b) for UE group subscriptions, wherein the profile comprises an address of the UDM node (200); and 31 store (S304) the profile.

32. A computer program product (1310a, 1310b, 1310c) comprising a computer program (1320a, 1320b, 1320c) according to at least one of claims 29, 30 and 31, and a computer readable storage medium (1330) on which the computer program is stored.