US-12621788-B2 - Technique for maintaining a subscription of a subscriber NF

US12621788B2US 12621788 B2US12621788 B2US 12621788B2US-12621788-B2

Abstract

A technique for maintaining a subscription of a subscriber Network Function, NF, for receiving events related to a User Equipment, UE, from a serving NF in a telecommunication system is disclosed, wherein the UE is served by a first instance of the serving NF. A method implementation of the technique is performed by the first instance of the serving NF and comprises receiving (S 502 ) a subscription request from the subscriber NF, the subscription request including a persistence indication indicating that the subscription is to be maintained, triggering (S 504 ) generating subscription restoration information enabling restoration of the subscription in case the first instance of the serving NF ceases serving the UE, and triggering (S 506 ) storing the subscription restoration information in a data storage function of the telecommunication system in association with the UE, wherein the subscription restoration information is to be used by a second instance of the serving NF for restoring the subscription if the first instance of the serving NF ceases serving the UE.

Inventors

Miguel Angel PUENTE PESTAÑA
Ulf Mattsson
Maria Belen Pancorbo Marcos
Miguel Angel Garcia Martin

Assignees

TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date: 20260505
Application Date: 20200701
Priority Date: 20200519

Claims (20)

1 . A method for maintaining an event subscription of a subscriber Network Function (NF) for receiving events related to a User Equipment (UE) from a serving NF in a telecommunication system, the UE being served by a first instance of the serving NF, the method being performed by the first instance of the serving NF and comprising: receiving an event subscription request from the subscriber NF, the event subscription request including a persistence indication indicating that the event subscription is to be maintained, the event subscription being for receiving events related to the UE from the serving NF; triggering generating subscription restoration information enabling restoration of the event subscription for receiving events related to the UE from the serving NF in case the first instance of the serving NF ceases serving the UE, the subscription restoration information comprising at least a type of event subscribed to and an event subscription context; and triggering storing the subscription restoration information in a data storage function of the telecommunication system in association with the UE, the subscription restoration information used by a second instance of the serving NF for restoring the event subscription for receiving events related to the UE from the serving NF if the first instance of the serving NF ceases serving the UE.
2 . The method of claim 1 , wherein the subscription restoration information is stored as part of a context maintained for the UE in the telecommunication system.
3 . The method of claim 1 , wherein ceasing serving the UE occurs responsive to the UE being temporarily unconnected to the telecommunication system, and wherein the first instance of the serving NF and the second instance of the serving NF are the same.
4 . The method of claim 1 , wherein the first instance of the serving NF ceases serving the UE responsive to a reallocation of the serving NF from the first instance of the serving NF to the second instance of the serving NF, and wherein the first instance of the serving NF and the second instance of the serving NF are different.
5 . The method of claim 4 , further comprising triggering notifying the subscriber NF that the second instance of the serving NF now serves the UE.
6 . The method of claim 1 , wherein storing the subscription restoration information in the data storage function of the telecommunication system is carried out via the subscriber NF.
7 . A method for maintaining an event subscription of a subscriber Network Function (NF) for receiving events related to a User Equipment (UE) from a serving NF in a telecommunication system, the UE being served by a second instance of the serving NF, the UE previously served by a first instance of the serving NF which has ceased serving the UE and the event subscription previously established with the first instance of the serving NF, the method being performed by the second instance of the serving NF and comprising: receiving, from a data storage function of the telecommunication system which stores the subscription restoration information in association with the UE, subscription restoration information enabling restoration of the event subscription, the event subscription being for receiving events related to the UE from the serving NF, the subscription restoration information comprising at least a type of event subscribed to and an event subscription context; and triggering restoring the event subscription using the subscription restoration information.
8 . The method of claim 7 , wherein ceasing serving the UE occurred responsive to the UE being temporarily unconnected to the telecommunication system, and wherein the first instance of the serving NF and the second instance of the serving NF are the same.
9 . The method of claim 7 , wherein the first instance of the serving NF ceased serving the UE responsive to a reallocation of the serving NF from the first instance of the serving NF to the second instance of the serving NF, and wherein the first instance of the serving NF and the second instance of the serving NF are different.
10 . The method of claim 7 , wherein the subscription restoration information is stored as part of a context maintained for the UE in the telecommunication system.
11 . The method of claim 7 , further comprising triggering notifying the subscriber NF that the second instance of the serving NF now serves the UE.
12 . The method of claim 7 , further comprising: triggering generating updated subscription restoration information enabling restoration of the event subscription in case the second instance of the serving NF ceases serving the UE; and triggering storing the updated subscription restoration information in the data storage function of the telecommunication system in association with the UE, wherein the updated subscription restoration information is to be used by a third instance of the serving NF for restoring the event subscription if the second instance of the serving NF ceases serving the UE.
13 . A method for maintaining an event subscription of a subscriber Network Function (NF) for receiving events related to a User Equipment (UE) from a serving NF in a telecommunication system, the UE being served by a first instance of the serving NF, the method being performed by the subscriber NF and comprising: triggering sending an event subscription request to the first instance of the serving NF, the event subscription request including a persistence indication indicating that the event subscription is to be maintained, the persistence indication causing the first instance of the serving NF to trigger generating subscription restoration information enabling restoration of the event subscription in case the first instance of the serving NF ceases serving the UE, and to trigger storing the subscription restoration information in a data storage function of the telecommunication system in association with the UE, the subscription restoration information to be used by a second instance of the serving NF for restoring the event subscription if the first instance of the serving NF ceases serving the UE, the event subscription being for receiving events related to the UE from the serving NF, the subscription restoration information comprising at least a type of event subscribed to and an event subscription context.
14 . The method of claim 13 , wherein the subscription restoration information is to be stored as part of a context maintained for the UE in the telecommunication system.
15 . The method of claim 13 , wherein storing the subscription restoration information in the data storage function of the telecommunication system is to be carried out via the subscriber NF.
16 . The method of claim 13 , wherein when ceasing serving the UE occurs responsive to the UE being temporarily unconnected to the telecommunication system, the first instance of the serving NF and the second instance of the serving NF are the same.
17 . The method of claim 13 , wherein when the first instance of the serving NF ceases serving the UE responsive to a reallocation of the serving NF from the first instance of the serving NF to the second instance of the serving NF, the first instance of the serving NF and the second instance of the serving NF are different.
18 . The method of claim 13 , further comprising, when the first instance of the serving NF ceases is serving the UE, receiving a notification informing the subscriber NF that the second instance of the serving NF now serves the UE.
19 . The method of claim 18 , wherein the notification is received from at least one of the first instance of the serving NF, the second instance of the serving NF, and the data storage function of the telecommunication system.
20 . A method for maintaining an event subscription of a subscriber Network Function (NF) for receiving events related to a User Equipment (UE) from a serving NF in a telecommunication system, the UE being served by a first instance of the serving NF, the method being performed by a data storage function of the telecommunication system and comprising: receiving a request to store subscription restoration information in association with the UE, the subscription restoration information enabling restoration of the event subscription in case the first instance of the serving NF ceases serving the UE, the event subscription being for receiving events related to the UE from the serving NF, the subscription restoration information comprising at least a type of event subscribed to and an event subscription context; triggering storing the subscription restoration information; and triggering providing the stored subscription restoration information to a second instance of the serving NF, the subscription restoration information to be used by the second instance of the serving NF for restoring the event subscription if the first instance of the serving NF ceases serving the UE.

Description

TECHNICAL FIELD The present disclosure generally relates to telecommunication systems. In particular, a technique for maintaining a subscription of a subscriber Network Function (NF) for receiving events related to a User Equipment (UE) from a serving NF in a telecommunication system is presented. The technique may be embodied in methods, computer programs, apparatuses and systems. BACKGROUND Mobile communication systems of the fifth generation (5G), especially their Core Network (CN) architectures, generally make use of the Service Based Architecture (SBA) paradigm in which each NF may provide—as a “producer”—one or more “services” to one or more “consumers”. FIG. 1 illustrates the general 3GPP reference architecture of 5G systems with particular focus on charging and analytics, which includes typical NFs of a 5G system like an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a Policy Control Function (PCF), a Unified Data Management (UDM) function, a Unstructured Data Storage Function (UDSF), a Unified Data Repository (UDR), and a Network Data Analytics Function (NWDAF) for analytics purposes. As illustrated in FIG. 2a, in such architecture, any NF is allowed to request network analytics information from the NWDAF via the Nnwdaf interface. The NWDAF belongs to the same Public Land Mobile Network (PLMN) in which the NF that consumes the analytics information is located. The Nnwdaf interface is defined for the NFs to request subscription to network analytics delivery for a particular context, to cancel subscription to network analytics delivery, and to request a specific network analytics report for a particular context, for example. FIG. 2b shows an overview of such services provided by the NWDAF in accordance with the SBA. Various analytics can be requested depending on the particular interest of the consumer, including slice load level, observed service experience, NF load, network performance, UE mobility, UE communication, user data congestion, and Quality of Service (QoS) sustainability, for example. These analytics are specified in 3GPP TS 23.288, such as 3GPP TS 23.288 v16.2.0, for example. 3GPP TS 23.288 generally defines a plurality of solutions for data collection from NFs for analytics purposes, which include generic management services offered by Operations, Administration and Maintenance (OAM), exposure services offered by NFs, and other NF services, such as Network Repository Function (NRF) services, for example. When data is collected from NFs via existing NF exposure services in order to produce UE related analytics services, such as via Event Exposure Services offered by AMFs, SMFs, PCFs or UDMs via their Namf, Nsmf, Npcf, Nudm interfaces (defined in 3GPP TS 23.502, such as 3GPP TS 23.502 v16.3.0, for example), the NWDAF may subscribe/unsubscribe at the relevant NFs to be notified on related events. This is schematically illustrated in FIG. 3. The NWDAF must thus interact with the relevant NFs to request or subscribe to the exposure services for data collection and, in order to generate patterns from the collected user data, such as mobility or application usage patterns, the NWDAF may need to collect relevant user data continuously, such as several days, weeks, etc. During this time, however, the UE may attach/detach from the network, Protocol Data Unit (PDU) sessions may be established/released, and NFs allocated to the UE may change due to UE mobility, for example, such that the subscriptions to the exposure services may get lost over time. Although 3GPP currently defines a procedure for AMF exposure services to allow that subscriptions to events in an AMF are transferred to another AMF in case the UE moves and gets reallocated to the other AMF, such procedure only provides a solution for the mobility problem with respect to AMFs. However, such solution does not allow maintaining subscriptions if the UE deregisters and reregisters with the network or if PDU sessions are entirely released and reestablished, in which case all event subscriptions will generally be lost. Also, such solution does not allow maintaining subscriptions if an SMF and UPF allocated to a PDU session are reassigned due to mobility of the UE to a closer SMF and UPF, for example. In these cases, the NWDAF will no longer get any notifications for data collection and it will not be able to provide accurate analytics reports anymore. SUMMARY Accordingly, there is a need for a technique for maintaining a subscription of a subscriber NF that avoids one or more of these problems, or other problems. According to a first aspect, a method for maintaining a subscription of a subscriber NF for receiving events related to a UE from a serving NF in a telecommunication system is provided, wherein the UE is served by a first instance of the serving NF. The method is performed by the first instance of the serving NF and comprises receiving a subscription request from the subscriber NF, the subscript