Enhancement of UE policy control service to ensure removal of any UE policy before disabling UE policy association for a ue

Abstract

The present disclosure provides a method performed by an access and mobility management function (200), AMF, including sending to a policy function (210) information to instruct the PCF to remove User Equipment policies at the UE (112) after obtaining subscription data indicating UE policy association is disabled, receiving notification from the policy function (210) that UE policy association can be terminated, and invoking a UE policy association delete service operation. The disclosure also provides a method performed by a policy function (210) including receiving from an access and mobility management function (200) information to remove User Equipment policies due to subscription data change indicating UE policy association indicator set to disabled, removing UE policies and sending notification to the access and mobility management function (200) that UE policy association can be terminated, and deleting established UE policy association upon receiving deletion request.

Description

ENHANCEMENT OF UE POLICY CONTROL SERVICE TO ENSURE REMOVAL OF ANY UE POLICY BEFORE DISABLING UE POLICY ASSOCIATION FOR A UE FIELD OF INVENTION

[0001] The present disclosure relates to telecommunications networks and user equipment policy management, and more particularly to methods performed by access and mobility management functions and policy control functions, network nodes, and computer readable memory for ensuring removal of user equipment policies before disabling user equipment policy associations in fifth generation (5G) core and future generation core networks.BACKGROUND

[0002] In the context of 3GPP 5G systems handling UE policy associations, 3GPP has recently introduced UE subscription (Access and Mobility Management subscription data) to allow per UE establishment of UE Policy Association. See below the relevant attribute copied from section 6.1.6.2.4 on TS 29.503.TS 23.503 section 6.1.2.2.5 describes handling of UE Policy Association accordingly. Of particular interest is note 3 (reproduced below)."NOTE 3:A possible reason to set the UE Policy Association indicator to "enabled" is that either there are service specific parameters for e.g. a SUPI in UDR or UE Policies are available for e.g. a SUPI provisioned in the PCF. Before setting the indicator to "disabled", the operator needs to ensure that there are no UE Policies stored for any of these services in the UE, by revoking the authorization for the service specific information, for Service Type "AF guidance for URSP", for all of the AFs with activeauthorizations, as defined in clause 4.15.6.7a of TS 23.502 [3] and by triggering the PCF to remove the UE Policies in the UE if any or both. "

[0003] The AMF in 5G system uses the indicator if received from UDM to determine if UE policy association is to be established or not or to be terminated.

[0004] Further Fig. A shows the current standard procedure based on 3GPP TS 23.502 V.19.2.0 for AMF-initiated UE policy association termination after initially being established which can be triggered by a change of the value of the UE Policy Association indicator (uePolicylnd) to disabled as received from UDM. This procedure concerns both roaming and non-roaming scenarios. In the non-roaming case, the V-PCF is not involved and the role of the H-PCF is performed by the PCF. For the roaming scenarios, the V-PCF interacts with the AMF. The V-PCF contacts the H-PCF to request removing UE Policy Association. The steps of the current procedure are reproduced herein:

[0005] l.The AMF decides to terminate the UE Policy Association if the AMF received from the UDM the uePolicylnd set to disabled.2. The AMF sends the Npcf UEPolicyControl Delete service operation including UE Policy Association ID to the (V-)PCF.3. The (V-)PCF removes the policy context for the UE and replies to the AMF with an Acknowledgement including success or failure. The V-PCF may interact with the H-PCF. The (H-)PCF may unsubscribe to subscriber policy data changes with UDR by Nudr DM Unsub scribe (Subscription Correlation Id). The AMF removes the UE Policy Context.Step 4 and Step 5 apply only to the roaming case.4. The V-PCF sends the Npcf UEPolicyControl Delete service operation including UE Policy Association ID to the H-PCF.5. The H-PCF removes the policy context for the UE and replies to the V-PCF with an Acknowledgement including success or failure.Optionally, based on operator policies, as described in clause 6.1.1.4 of TS 23.503, the PCF may store the policy counters into the UDR by invoking Nudr DM Update.The H-PCF may unsubscribe to subscriber policy data changes with UDR by Nudr DM Unsub scribe (Subscription Correlation Id) for subscriber policy changes. In the non-roaming case, the PCF may unsubscribe to analytics from NWDAF.

[0006] Based on the above procedure the UE policy association is terminated between the AMF and the PCF, however any UE policy in the UE remains. There is no known mechanism specified in 3 GPP on how to remove the UE policies in the UE, if any, in the case of AMF obtaining from the UDM the UE policy Association indicator (uePolicylnd) indicating a change from "enabled" to "disabled".

[0007] Furthermore, Note 3 in TS 23.503 section 6.1.2.2.5 cited above does not elaborate on the solution at all.

[0008] It has been appreciated that a solution is needed that overcomes one or more of these problems.SUMMARY

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description.

[0010] In a first aspect, a method performed by an access and mobility management function, AMF, is provided. The method comprises sending to the policy function information to instruct the PCF to remove any User Equipment (UE) policies at the UE as a result of obtaining from a subscription data node a UE subscription data indicating the UE policy association is disabled, receiving a notification from the policy function that the UE policy association can be terminated, and invoking a UE policy association delete service operation to delete the UE policy association in the policy function in response to the received notification. In this way, the exchange of messages including a dedicated information between the AMF and the PCF prior to deleting any UE policy associations enables the PCF to remove UE Policies at the UE. The PCF may initiate the removal of the UE Policies in the UE upon receiving the information including the instruction or indication to remove any User equipment policies at the UE from the AMF. This method ensures that UE policies are properly removed before terminating the policy association, preventing orphaned policies from remaining in the UE. The coordinated approach between the AMF and PCF provides a reliable mechanism for complete policy cleanup that addresses the gap in current 3 GPP specifications.

[0011] The access and mobility management function may have a User Equipment (UE) policy association established with a policy function for a UE and the information may be a notification, a policy update or a policy control request trigger to indicate that the UE policy association is to be terminated that the UE policy association has been disabled, after obtaining a UE subscription change indicating the UE policy association is disabled.

[0012] This approach provides flexibility in how the AMF can communicate the termination requirement to the PCF, allowing for different signaling mechanisms depending on the current state of the policy association.

[0013] The information may comprise an Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change.

[0014] Using a specific information element provides a standardized and unambiguous way to signal the termination requirement, enabling clear communication between network functions about the reason for policy association termination.

[0015] The IE may be included in Policy AssociationUpdateRequest document or data structure or Policy AssociationCreateRequestdata document or data structure.

[0016] Incorporating the information element into existing request structures leverages established communication protocols and minimizes the need for new signaling procedures.

[0017] The IE may be "reqTermPol Assoc".

[0018] This specific information element name provides a clear and descriptive identifier for the termination request functionality.

[0019] The information may be one of an Npcf UEPolicyControl Update request when UE policy association exists at the AMF or Npcf UEPolicyControl Create request when UE policy association does not yet exist for the UE at the AMF.

[0020] Supporting both update and create scenarios ensures the solution works regardless of whether a policy association is already established, providing comprehensive coverage for different operational states.

[0021] The UE subscription data indicating the UE policy association is disabled may comprise a UE policy association indicator indicating UE policy association is disabled and may comprise a flag indicating the UE policy association is changed in the subscription data node from enabled to disabled.

[0022] This subscription data structure enables the AMF to detect when policy association status changes and respond appropriately to ensure proper policy cleanup.

[0023] Prior to sending the information to the policy function, the method may include at least one of checking that the policy function indicated support of a feature of receiving instruction to remove any User Equipment (UE) policies prior to terminating the UE policy association, and checking that the access and mobility management function and policy function support the feature of sending and receiving respectively instruction to remove any User Equipment (UE) policies prior to terminating the UE policy association.

[0024] Feature capability checking ensures that both network functions support the enhanced termination procedure before attempting to use it, preventing compatibility issues and ensuring graceful fallback to standard procedures when needed.

[0025] The feature may be negotiated during the UE policy association establishment.

[0026] Negotiating feature support during association establishment enables early determination of capabilities and allows for optimal procedure selection throughout the association lifecycle.

[0027] In a second aspect, a method performed by a policy function is provided. The method comprises receiving from an access and mobility management information to instruct the policy function to remove any User Equipment (UE) policies as a result of subscription data change indicating a UE policy association indicator set to disabled, removing UE policies in the UE if any and sending a notification to the access and mobility management function to indicate that the UE policy association can be terminated, and deleting any established UE policy association in response to receiving a request to delete UE policy association.

[0028] This method enables the policy function to properly handle policy removal and coordinate with the AMF to ensure complete cleanup of UE policies before association termination, addressing the requirements specified in 3 GPP standards for policy removal when subscription status changes.

[0029] The policy function may have a User Equipment (UE) policy association established with an access and mobility management function for a UE and the information may be a notification, a policy update or a policy control request trigger to indicate that the UE policy association is to be terminated or that the UE policy association has been disabled.

[0030] This flexibility in receiving termination instructions allows the policy function to respond appropriately to different types of signaling from the AMF while maintaining consistent policy cleanup behavior.

[0031] The information may comprise an Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change.

[0032] Using a standardized information element enables the policy function to clearly understand the reason for termination and respond with appropriate policy cleanup actions.

[0033] The IE may be included in Policy AssociationUpdateRequest document / data structure or Policy AssociationCreateRequest document / data structure.

[0034] Supporting the information element in existing request structures allows the policy function to process termination instructions through established communication channels.

[0035] The IE may be "reqTermPol Assoc".

[0036] This specific information element provides a clear identifier that the policy function can recognize and process for termination handling.

[0037] The information may be one of an Npcf UEPolicyControl Update request when UE policy association exists at the AMF or Npcf UEPolicyControl Create request when UE policy association do not yet exist for the UE at the AMF.

[0038] Supporting both request types ensures the policy function can handle termination instructions regardless of the current association state at the AMF.

[0039] The method may further comprise checking whether a feature of notifying the AMF the UE policy association can be terminated after deletion of the UE policies in the UE, is supported.

[0040] Feature checking enables the policy function to determine whether enhanced coordination procedures are available and respond accordingly to ensure proper policy cleanup.

[0041] The feature may be negotiated during the UE policy association establishment.

[0042] Early feature negotiation allows the policy function to establish the appropriate coordination procedures from the beginning of the association lifecycle.

[0043] In a third aspect, a network node configured to perform the method of any one of the preceding methods is provided.

[0044] This network node implementation enables deployment of the enhanced policy termination procedures in actual network infrastructure, providing the hardware and software platform needed to execute the coordinated policy cleanup functionality.

[0045] In a fourth aspect, a network node comprising one or more processors and memory comprising instructions which when executed by the one or more processors enable the network node to perform any one of the preceding methods is provided.

[0046] This processor and memory architecture provides the computational resources and stored instructions necessary to implement the policy termination coordination procedures in network equipment.

[0047] In a fifth aspect, a computer readable memory comprising instructions which when executed by one or more processors of one or more servers configures the one or more servers to perform any one of the preceding methods is provided.

[0048] This computer-readable memory implementation enables software-based deployment of the enhanced policy termination functionality, allowing for flexible implementation across different server platforms and virtualized network environments.BRIEF DESCRIPTION OF FIGURES

[0049] Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which:

[0050] Figure 1 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented;

[0051] Figures 2 and 3 illustrate example embodiments of the cellular communication system of Figure 1;

[0052] Figure 4 is a flow chart of an Access and mobility management entity (e.g., AMF) for properly terminating UE policy association in accordance with some embodiments;

[0053] Figure 5 is a flow chart of a policy node for properly terminating UE policy association in accordance with some embodiments;

[0054] Figure 6a and 6b illustrate two problem scenarios resulting in UE policies not to be removed and avoided by the proposed embodiments;

[0055] Figures 7a, 7b and 7c are flow diagrams of an AMF initiated UE policy association termination in a non-roaming scenario according to some embodiments;

[0056] Figures 8a, 8b and 8c are flow diagrams of an AMF initiated UE policy association termination in a roaming scenario according to some embodiments;

[0057] Figures 9, 10, and 11 are schematic block diagrams of example embodiments of a network node.

[0058] Common reference numerals are used throughout the figures to indicate similar features.DETAILED DESCRIPTION

[0059] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0060] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0061] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and viceversa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.

[0062] Radio Node: As used herein, a “radio node” is either a radio access node or a wireless communication device.

[0063] Radio Access Node: As used herein, a “radio access node” or “radio network node” or “radio access network node” is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and / or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.

[0064] Core Network Node: As used herein, a “core network node” is any type of node in a core network or any node that implements a core network function. The node can be a server or system of distributed servers. Some examples of a core network node include, e.g., an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Short message service function (SMSF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), a Network slice Admission Control function (NSACF) or the like. The Core network functions may be virtualized / containerized on a node, server, distributed servers, or implemented as a dedicated function on a dedicated physical node (compute, memory, and network). Other future core network functions in future core networks such as 6G and beyond are also applicable for this invention.

[0065] Communication Device: As used herein, a “communication device” is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumerelectronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and / or data via a wireless or wireline connection.

[0066] Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (loT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and / or data via a wireless connection.

[0067] Network Node: As used herein, a “network node” is any node that is either part of the RAN or the core network of a cellular communications network / system.

[0068] Note that the description given herein focuses on a 3 GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0069] Note that, in the description herein, reference may be made to the term “cell”; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0070] Figure 1 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 100 is a 5G system (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC); however, the present disclosure is not limited thereto. In this example, the RAN includes base stations 102-1 and 102-2, which in the 5GS include NR base stations (gNBs) and optionally next generation eNBs (ng-eNBs) (e.g., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells 104-1 and 104-2. The base stations 102-1 and 102-2 are generally referred to herein collectively as basestations 102 and individually as base station 102. Likewise, the (macro) cells 104-1 and 104-2 are generally referred to herein collectively as (macro) cells 104 and individually as (macro) cell 104. The RAN may also include a number of low power nodes 106-1 through 106-4 controlling corresponding small cells 108-1 through 108-4. The low power nodes 106-1 through 106-4 can be small base stations (such as pico or femto base stations) or RRHs, or the like. Notably, while not illustrated, one or more of the small cells 108-1 through 108-4 may alternatively be provided by the base stations 102. The low power nodes 106-1 through 106-4 are generally referred to herein collectively as low power nodes 106 and individually as low power node 106. Likewise, the small cells 108-1 through 108-4 are generally referred to herein collectively as small cells 108 and individually as small cell 108.

[0071] In particular when the NG-RAN consists of gNBs (5G or beyond) connected to the 5GC through the NG interface, a gNB may further consist of a gNB-control unit (CU) and one or more gNB -Distribution Unit(s) (DU(s)). A gNB-CU and a gNB-DU is connected via Fl interface as illustrated in Figure 1 A.

[0072] The cellular communications system 100 also includes a core network 110, which in the 5G System (5GS) is referred to as the 5GC. The base stations 102 (and optionally the low power nodes 106) are connected to the core network 110.

[0073] The base stations 102 and the low power nodes 106 provide service to wireless communication devices 112-1 through 112-5 in the corresponding cells 104 and 108. The wireless communication devices 112-1 through 112-5 are generally referred to herein collectively as wireless communication devices 112 and individually as wireless communication device 112. In the following description, the wireless communication devices 112 are oftentimes UEs and as such sometimes referred to herein as UEs 112, but the present disclosure is not limited thereto.

[0074] Figure 2 illustrates a wireless communication system represented as a 5G network architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point-to-point reference point / interface. Figure 2 can be viewed as one particular implementation of the system 100 of Figure 1. The embodiments in the reminder of these document are described within the context of 5G 3GPP network architecture using the 5G terminology, but the embodiments are also applicable to other systems / networks that use UE policies. Example of those systems / networks may be 6G 3 GPP systems / networks or subsequent generation system.

[0075] Seen from the access side the 5G network architecture shown in Figure 2 comprises a plurality of UEs 112 connected to either a RAN 102 or an Access Network (AN) as well as an AMF 200. Typically, the R(AN) 102 comprises base stations, e.g. such as eNBs or gNBs or similar. Seen from the core network side, the 5GC NFs shown in Figure 2 includes but not limited to a NSSF 202, an AUSF 204, a UDM 206, the AMF 200, a SMSF 220, a SMF 208, a PCF 210, and an Application Function (AF) 212.

[0076] Reference point representations of the 5G network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE 112 and AMF 200 including any UE policies from PCF 210 to UE 112. The AMF 200 communicates with UDM 206 over the N8 reference point as illustrated in Figure 2. N15 and N7 are defined and used between the PCF 210 and the AMF 200 and between the PCF 210 and the SMF 208, respectively. The reference points for connecting between the AN 102 and AMF 200 and between the AN 102 and UPF 214 are defined as N2 and N3, respectively. There is a reference point, Nil, between the AMF 200 and SMF 208, which implies that the SMF 208 is at least partly controlled by the AMF 200. N4 is used by the SMF 208 and UPF 214 so that the UPF 214 can be set using the control signal generated by the SMF 208, and the UPF 214 can report its state to the SMF 208. N12 is required for the AMF 200 to perform authentication of the UE 112. N8 and N10 are defined because the subscription data of the UE 112 is required for the AMF 200 and SMF 208. N80 is the reference point between AMF 200 and NSACF 207 and N81 reference point is between SMF 208 and NSACF 207.

[0077] The 5GC network aims at separating UP and CP. The UP carries user traffic while the CP carries signaling in the network. In Figure 2, the UPF 214 is in the UP and all other NFs, i.e., the AMF 200, SMF 208, PCF 210, AF 212, NSSF 202, AUSF 204, and UDM 206, are in the CP. Separating the UP and CP guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from CP functions in a distributed fashion. In this architecture, UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and data network for some applications requiring low latency.

[0078] The 5G core network architecture is composed of modularized functions. For example, the AMF 200, SMF 208 and for example PCF 210 are independent functions in theCP. Separated AMF 200 and SMF 208 allow independent evolution and scaling. Modularized function design enables the 5GC network to support various services flexibly.

[0079] Each NF interacts with another NF directly. It is possible to use intermediate functions to route messages from one NF to another NF. In the CP, a set of interactions between two NFs is defined as service so that its reuse is possible. This service enables support for modularity. The UP supports interactions such as forwarding operations between different UPFs.

[0080] Figure 3 illustrates a 5G network architecture using service-based interfaces between the NFs in the CP, instead of the point-to-point reference points / interfaces used in the 5G network architecture of Figure 2. However, the NFs described above with reference to Figure 2 correspond to the NFs shown in Figure 3. The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In Figure 3 the service based interfaces are indicated by the letter “N” followed by the name of the NF, e.g. Namf for the service based interface of the AMF 200 and Npcf for the service based interface of the PCF 210, etc. Any NFs depicted in Figure 2 can interact with the NEF 216 and / or NRF 218 of Figure 3 as necessary, though not explicitly indicated in Figure 2.

[0081] Some properties of the NFs shown in Figures 2 and 3 may be described in the following manner. The AMF 200 provides UE-based authentication, authorization, mobility management, etc. A UE 112 even using multiple access technologies is basically connected to a single AMF 200 because the AMF 200 is independent of the access technologies. The PCF 210 is responsible for session and non-session management policy related functionality. The non-session management related functionality comprises an Access and mobility related policy control and UE policy information control. The UE policy information includes Access Network Discovery & Selection Policy (ANDSP), UE Route Selection Policy (URSP), V2X policies as described in 3GPP TS 23.503 clause 6.1.2.2. The UE policy information shall be provided from the PCF to the AMF via N15 / Namf interface when UE policy association is established / modified, and then from AMF to the UE via the N1 interface as described in clause 4.2.4.3 of TS 23.502. The AMF shall not change the UE policy information provided by PCF.

[0082] The SMF 208 is responsible for session management and allocates Internet Protocol (IP) addresses to UEs. It also selects and controls the UPF 214 for data transfer. If aUE 112 has multiple sessions, different SMFs 208 may be allocated to each session to manage them individually and possibly provide different functionalities per session. The AUSF 204 supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM 206 stores subscription data of the UE 112. Many NFs including AMF 200 communicate with UDM 206 to obtain subscription data and / or notification which can include the UE policy indicator to indicate whether UE policy association is to be enabled or disabled. When enabled the AMF can establish the UE policy association with PCF and trigger UE policies to be sent to the UE. The Data Network (DN), not part of the 5GC network, provides Internet access or operator services and similar.

[0083] An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

[0084] As stated above, there currently exist certain challenges as there is no known mechanism specified in 3GPP on how to remove the UE policies in the UE 112 if any, in the case of UE policy Association indicator of a UE is received from the UDM 206 at the AMF 200 to indicate a change of UE policy association from “enabled” to “disabled”. Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. Embodiments of the solutions described herein are described using the 3GPP 5G systems, but as indicated can be applied to a 6G system and systems beyond 6G if equivalent functionality is supported.

[0085] The embodiments enable an AMF 200 when receiving from the UDM 206 or UDR• the UE policy Association indicator of a UE indicating the value is set to “disabled”, or • the UE policy Association indicator (aka UE policy indicator) of a UE indicating the value set to “disabled” and indicator that the UE policy indicator was changed from “enabled” to “disabled”,the AMF 200 first notifies the PCF 210 that the UE Policy Association is going to be terminated due to subscription change. For example, the Npcf UEPolicyControl Update service operation (in 3GPP TS 29.525) invoked by the AMF 200 in the PCF 210 is updated to include a new IE "reqTermPol Assoc" in Policy AssociationUpdateRequest document (Section 5.6.2.4 in 29.525). When the AMF 200 gets notified by the UDM 206 of switch from "enabled" to "disabled" of uePolicylnd attribute, the AMF 200 sends Npcf UEPolicyControl Updaterequest to the PCF 210 with "reqTermPolAssoc" IE (indicating the UE Policy Association needs to be terminated due to UE subscription change and PCF may remove the UE policies in the UE, if any).

[0086] The PCF 210 should first remove the UE policies in the UE, if any. After removing the UE policies in the UE, the PCF 210 can inform the AMF 200 that the UE the UE Policy Association can be terminated / deleted / removed, and the AMF 200 then terminates / removes / deletes the UE Policy Association. In some aspect, the AMF may then acknowledge to UDM / UDR that it has successfully handled the transition from “enabled” to “disabled” when the indication of a change of UE policy indicator from “enabled” to “disabled” was received. This would allow UDM / UDR to not notify AMF of this transition / change subsequently, as the UDM / UDR is ascertained that the UE policies are removed.

[0087] More in detail, Figure 4 shows a flow chart according to embodiments of the disclosure wherein an AMF sends as shown in step 400 to a policy function or policy control function, PCF, 210 information to instruct the PCF to remove any User Equipment (UE) policies at the UE 112 as a result of obtaining from a subscription data node, e. g. the UDM 206 a UE subscription data indicating the UE policy association is disabled. It then receives, as shown in step 410, a notification from the policy function that the UE policy association can be terminated, and invoke a UE policy association delete service operation to delete the UE policy association in the policy function in response to the received notification, as shown in steps 400 and 410. In an alternative embodiment the method executes in step 400 sending to the policy function 210 a notification or a policy update to indicate that the UE policy association is to be terminated that the UE policy association has been disabled, after obtaining a UE subscription change indicating the UE policy association is disabled. This may apply e.g. if the AMF has a User Equipment (UE) policy association established with a policy function for a UE. In such a case it is assumed that the AMF has established the UE policy association based on the UE subscription information from a user data subscription management function (e.g., UDM) indicating that UE policy association is enabled, e.g., uePolicylnd set to true indicating UE policy association is enabled.

[0088] The method executed by the Access and Mobility Management function such as anAMF 200 in 5G system for a UE 112 that is registered with AMF 200 and for which a UE 112 policy association with a policy function 210 has been established in which the UE 112 has been provided UE 112 policy information. The AMF 200 may or may not have anestablished UE 112 policy association with the PCF 210 (UE 112 not registered). Note that an AMF 200 that has an existing UE 112 policy association is for a registered UE 112 and the UE 112 policy association was allowed to be established based on receiving the UE 112 subscription information from a user data subscription management function (e.g., UDM 206) indicating that UE 112 policy association is enabled, e.g., uePolicylnd set to true indicating UE 112 policy association is enabled.

[0089] At step 700, for the registered UE 112 case, after obtaining an indication from the UDM 206 of a UE 112 subscription information change of UE 112 policy association indicating the UE 112 policy association is disabled, i.e., AMF 200 receives for example Nudm SDM Notification which includes the UE 112 Policy Association indicator set to false indicating UE 112 policy association is disabled (uePolicy!nd=false)) and may include a flag indicating that the UE 112 policy Association indicator was changed from "enabled" to "disabled", e.g., "changeflag" (see Table 9-0 for details of subscription data), the AMF 200, as UE 112 Policy Association is assumed to have been established between the AMF 200 and the policy function ((H)PCF 210), performs the step of informing / notifying / updating the policy function 210 that UE 112 Policy Association needs to be terminated due to subscription change in UE 112 policy association indicating UE 112 policy association is now disabled, or notifying that the UE 112 policy association has been disabled thus providing the policy function 210 the opportunity to remove any UE 112 Policy in the UE 112. For example, the AMF 200 updates the policy function 210 of the subscription change by sending Npcf UEPolicyControl Update request. The AMF 200 includes a new Information Element (IE) indicating the UE 112 Policy Association needs to be terminated due to UE 112 subscription change. For example the new IE is "reqTermPolAssoc" in Policy AssociationUpdateRequest document or data structure as the request body of within the request message Npcf UEPolicyControl Update request as specified in 3GPP 5G standard (see Table 10-1). The embodiment herein can be incorporated in different sections of the standards as illustrated below:3GPP TS 29.525 Section 5.6.2.45.6.2.4 Type Policy AssociationUpdateRequestTable 5.6.2.4-1: Definition of type Policy AssociationUpdateRequest"""""" ""

[0090] In another alternative, if the UE performed an initial registration with the AMF, and thus AMF has no subscription data for the UE and does not have a UE policy association with a PCF, the AMF as part of the registration requests fetches UE subscription data from the subscription data management function (e.g., UDM / UDR). The UDM / UDR provides subscription data comprising the UE Policy Association indicator set to false indicating UE policy association is disabled (uePolicy!nd=false)) and if the UE policy association indicator was changed in UDM / UDR from enabled to disabled before the UE registration with the AMF, or the UDM / UDR did not receive a notification from a previous network where the UE previously registered that there are no remaining UE policies in the UE when UE policy associations were disabled, the AMF may also receive a flag indicating that the UE policy Association indicator was changed from "enabled" to "disabled", e.g., "changeflag" IE (see Table 9-0 for details of subscription data). When the changeflag is received, the AMF would create the UE policy association with the policy function in serving or home network) despite the UE policy association indicator indicating the UE policy is now disabled. The AMF performs the step of creating the UE policy association with the PCF first to provide the policyfunction the opportunity to remove any UE Policy in the UE. For example, the AMF creates the UE policy association with the policy function based on indication of the change in the subscription (changeflag) by sending Npcf UEPolicyControl Create request. The AMF includes a new Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change. For example the new IE is "reqTermPol Assoc" in Policy AssociationCreateRequest document or data structure as the request body of within the request message itself (See Table 9-1) . Once the PCF has removed any remaining UE policies in the UE, the AMF receives from the PCF

[0091] In some embodiment, prior to updating the policy function or creating a UE policy association, the AMF may check if the policy function also supports the feature of being notified of the UE policy association subscription change to disable to allow the policy function to remove any UE policies at the UE before terminating the UE policy association. The feature negotiation may be useful for backward compatibility with the legacy procedure described in Figure 4. The feature may be negotiated at the time of establishing the UE policy association between the AMF and the policy function if uePolicylnd from UDM was set to true. The feature capability, referred herein as "TermNotif ' (albeit any feature name can be used) indicates that the consumer (e.g., AMF) and the policy function support the notification procedure of that UE policy association is to be terminated to allow UE policies to first be removed from the UE before performing the procedure of deleting the UE policy association due to UE subscription change indicating the UE policy association is changed from enabled to disabled. For additional details of feature negotiation, see section "Feature negotiation" below (Table 12).

[0092] At step 710, when the AMF receives a notification from the policy function in response to the updating request of UE policy association at step 700 or in response to the UE policy creation with request to terminate the UE policy association (i.e., “reqTermPol Assoc”, where the notification is an indication that the UE Policy Association can now be terminated, the AMF initiates the procedure to delete the UE Policy Association at the policy function using Npcf UEPolicyControl Delete service operation, i.e., sends a Npcf UEPolicyControl Delete Request to the Policy function to delete the UE policy association and receiving a response from the policy function indicating the UE policy association has been deleted.

[0093] The AMF may then notify the user data subscription management function (e.g., UDM), in response to receiving the changeflag as an indication to the UDM / UDR that anyremaining policies in the UE have been removed as a result of disabling the UE policy association. The UDM forwards the indication to the UDR (which can then reset the falg). As long as the UE policy association remains disabled in the UDR / UDM, the UDR / UDM does not need to send the flag to the AMF in subsequent requests for subscription data or subscription data change of other subscription data for the UE, unless the UE policy association has been enabled and disabled again in the UDR / UDM. If the AMF does not receive the changeflag, an AMF may opt not to use the termnotif feature with the PCF and may proceed with the legacy procedure of deleting the UE policy association. However, an AMF may still apply the termnotif feature even if the changeflag is not received. The use and signalling of the changeflag when UE policy association were changed in the UDR from enabled to disabled optimizes the behaviour at the AMF as it could save extra signalling steps with the PCF while still providing the certainty that the UE policies are removed as long as the changeflag is uniformly deployed across the network.

[0094] Figure 5 shows a flow chart according to embodiments of the disclosure wherein a policy function receives as shown in step 500 from an access and mobility management function, AMF, 200 information to instruct the policy function 210 to remove any User Equipment (UE) policies as a result of subscription data change indicating a UE policy association indicator set to disabled, removes UE policies in the UE 112 if any and sends a notification to the access and mobility management function 200 to indicate that the UE policy association can be terminated, and deletes any established UE policy association in response to receiving a request to delete UE policy association, as shown in steps 500 and 510. In an alternative embodiment the method executes in step 500 receiving from the access and mobility management function a notification or a policy update to indicate that the UE policy association is to be terminated or that the UE policy association has been disabled. This may apply e.g. if the AMF has a User Equipment (UE) policy association established with a policy function for a UE.

[0095] The method executed by a Policy Function as a PCF in 5G system applies for example for the following scenarios:• a UE that is registered with an access and mobility management function such as AMF in 5G and for which a UE policy association for a UE at the policy function has been created or established with the AMF.• A registering UE with the AMF, where no policy association has not yet been established.

[0096] At step 500, when the UE policy association exists (1), the PCF obtains information / notification / update from the AMF (or the like), the notification / update indicates that the UE Policy Association needs to be terminated due to notification (obtained at the AMF) of subscription change in UE policy association indicating UE policy association is now disabled, or that the UE policy association has been disabled, thus providing the policy function the opportunity to remove any UE Policy in the UE.

[0097] For example, the policy function receives Npcf UEPolicyControl Update request which includes a new Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change.

[0098] In another aspect, when the UE policy association doesn’t exist as a start (2) the PCF obtains from the AMF a request to establish / create a UE policy association (even if the AMF obtained subscription data indicating UE policy association indicator as disabled). The request to establish / create a UE policy association indicates that the UE Policy Association needs to be terminated due to notification (obtained at the AMF) of subscription change in UE policy association indicating UE policy association has been changed to disabled, thus providing the policy function the opportunity to remove any UE Policies in the UE.

[0099] For example, the policy function receives Npcf UEPolicyControl Update request or Npcf UEPolicyControl Create request which includes a new Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change. For example the new IE is “reqTermPol Assoc” in Policy AssociationUpdateRequest / Policy AssociationCreateRequest document or data structure as the request body within the Npcf UEPolicyControl Update request or Npcf UEPolicyControl Create request as specified in 3GPP 5G standard. The details of PolicyAssociationUpdateRequest / Policy AssociationCreateRequest are illustrated in Tables 10-1 and 9-2.

[0100] In some embodiment, the policy function may negotiate the feature of removing UE policies at UE policy association termination as a result of a UE policy association subscription change. The feature negotiation may be useful for backward compatibility with the legacy procedure described in Figure 4. The feature may be negotiated at the time of establishing / creating the UE policy association between the AMF and the policy function if uePolicylnd from UDM was set to true or set to false but the 'changeflag' is received. Thefeature capability, referred herein as "TermNotif1(albeit any feature name can be used) indicates that the consumer (e.g., AMF) and the policy function supports the notification procedure of that UE policy association is to be terminated to allow UE policies to first be removed from the UE before performing the procedure of deleting the UE policy association due to UE subscription change indicating the UE policy association is changed from enabled to disabled. For additional details of feature negotiation, see section "Feature negotiation" below (Table 12).

[0101] At step 510, the Policy function removes any UE policies, if any, by sending an empty UE Policy container to the UE via the AMF using existing UE policy delivery mechanism described in 3GPP TS 24.501, TS 29.525.

[0102] After removing any UE policies in UE, if any were available at the UE, the Policy function uses Npcf_UEPolicyControl_UpdateNotify service operation to notify AMF that the UE Policy Association can now be terminated after which the policy function is expected to receive a request to delete the UE policy association from the AMF. For example, the PCF deletes the UE policy association when the AMF invokes Npcf UEPolicyControl Delete service operation, i.e., receives a Npcf UEPolicyControl Delete Request from the AMF to delete the UE policy association and sending a response from the policy function indicating the UE policy association has been deleted.

[0103] The embodiments as disclosed herein avoid problems occurring while changing the status of existing UE policy associations and as further described hereafter. In Note 3 of 3GPP TS 23.503 section 6.1.2.2.5 cited above does not elaborate on the solution at all. To implement the solution, a feedback loop would be needed from PCF to UDRto Provisioning system. None of the operator would accept the need for feedback loop to provisioning system. This is not done in any other issue. Without the feedback loop, there is possibility of race condition or simply no chance of removing UE Policies before UE Policy Association is terminated. Figure 6a and 6b illustrate the issue in two scenario.

[0104] Figure 6a describes the first scenario where no UE Policy Association exists, and UE Policy Indicator is switched or changed from 'enabled' to 'disabled'. When the UE 112 registers with the AMF 200, there is no UE Policy Association between the AMF 200 and the PCF 210. In this scenario, the AMF 200 receives Subscription data from the UDM 206 containing the UE Policy Indicator is set to disabled or UE Policy Indicator=Disabled. Since the UE Policy indicator=disabled or is set to disabled, the AMF 200 won't create UE PolicyAssociation with the PCF 210. However, if the UE 112 that is registered contains UE policies, e.g. previously obtained, the PCF 210 would thus not be able to remove any of the UE Policies that may remain in the UE 112 as the UE policy association would not be established due to the UE policy indicator.

[0105] Figure 6b describes the second scenario where UE Policy Association exists, and UE Policy Indicator is switched or changed from 'enabled' to 'disabled'. Even if the setting of the UE Policy Indicator set to disabled orUE Policy Indicator=Disabled is done via provisioning when any UE policies are removed via policy data update, the two procedures cannot be guaranteed to secure UE Policies are removed from the UE 112. The two independent procedures 3a) and 3b) can run in parallel and get into race condition which may result in UE Policy Association being removed first. Thus, UE Policies in UE 112 cannot be removed.

[0106] The following embodiments describe embodiments when in the UDM / UDR, the UE policy have been disabled (i.e., changed from “enabled” to “disable”), the AMF receives the UE policy indicator set to “Disabled” and a change indicator. The AMF may or may not have UE policy association the PCF. Both scenarios are addressed.

[0107] For the scenario of transition from “enabled” to “disabled” of the UE policy, UDR notifies the UDM of the new status of the UE policy, i.e., “Disabled” and would include a “changeflag” to indicate that the UE policy was previously “enabled” and now changed to “disabled” according to some of the embodiments. The UDR may inform the UDM in Nnudr DataRepository GET response or Nnudr DataRepository Notify Request (as specified in 3GPP TS 29.505). The UDM would similarly include the UE policy indicator set to “Disabled” and the “changeflag” in subscription data to AMF in Nnudm SMD GET response (initial registration) or Nnudm SDM Notify Request when an change of the subscription data at the AMF is required (see 3GPP TS 29.503).

[0108] The Npcf UEPolicyControl Create service operation used by the AMF to create a UE policy association with PCF as well as Npcf UEPolicyControl Update service operation to update the UE policy association established between the AMF and the PCF (TS 29.525) are updated in accordance with the embodiments herein to include the new IE "reqTermPol Assoc" in Policy AssociationUpdateRequest document (Section 5.6.2.4 in 29.525). When the AMF receives from the UDM the UE policy indicator to "Disabled" and a changeflag to indicate a switch from "enabled" to "disabled" of uePolicylnd attribute , the AMF sends Npcf UEPolicyControl Create or Npcf UEPolicyControl Update request to the PCFwith "reqTermPolAssoc" IE (indicating the UE Policy Association needs to be terminated due to UE subscription change and PCF would remove the UE policies in the UE, if any UE policies in the UE). After removing the UE policies, the PCF will notify AMF that the UE Policy Association can now be removed, and AMF deletes UE Policy Association.

[0109] AMF then notifies UDM that necessary actions against “changeflag” has been taken care of. The UDM forwards the information to the UDR.

[0110] A new feature “TermNotif’ is proposed (as part of this disclosure) to support this enhancement. The new feature is to be negotiated between the AMF and the PCF.

[0111] The following Figures and detailed descriptions further elaborate on the details for each scenario.

[0112] Non-Roaming: AMF receives UE policy indicator indicating “Disabled”

[0113] The following embodiments describe embodiments when in the UDM / UDR, the UE policy have been disabled (i.e., changed from “enabled” to “disable”), the AMF has a UE policy association with the PCF and receives a UE policy indicator set to “Disabled”.

[0114] According to some embodiments, a modification / improvement of the existing procedure illustrated in Figure 4 are provided which enable successful removal of any UE Policies in the UE at subscription change, i.e., when the UE Policy Indicator in the UDM / UDR is changed from “enabled” to “disabled” and thus AMF received UE policy indicator set to “disabled”.

[0115] A new feature “TermNotif’ (other name can be used) is proposed (as part of this disclosure) to enable the use of the improved procedure between the AMF 200 and the PCF 210 and is also proposed to 3GPP TS 29.525 as shown further below.

[0116] Figure 7a illustrates the flow diagram for UE policy association termination for non-roaming scenario according to the embodiments herein.

[0117] Starting state: AMF established UE Policy Association since UE subscription initially indicated the UE Policy Association is enabled (UE Policy indicator is set to true indicating "enabled". The UE may have some UE policies.

[0118] Step 1: Operator disables the UE policy association, for example changes UE Policy Association indicator to false indicating "disabled". The UE subscription comprisinguePolicylnd is modified as the value of the indicator is modified. The UE subscription is also updated in UDR.

[0119] Step 2: The AMF 200 is notified by the UDM 206 / UDR that UE Policy Association is to be disabled for the UE. The UDM 206 uses Nudm SDM Notification service operation and include the UE Policy Association indicator set to false indicating UE policy association is disabled (uePolicy!nd=false).

[0120] Step 3: If UE Policy Association exists, the AMF 200 informs the PCF 210 that UE Policy Association needs to be terminated due to subscription change in UE policy association (uePolicylnd indicating UE policy association Is disabled). The AMF 200 thus provides the PCF 210 the opportunity to remove any UE Policy in the UE. In some embodiment, the AMF 200 may determine that it needs to first notify the PCF 210 that UE policy association is to be terminated to allow the PCF 210 to remove the UE policies at the UE before terminating the UE policy association based on feature negotiation with the PCF 210, i.e., AMF 200 and / or PCF 210 exchange the feature capability, referred herein as "TermNotif1(albeit any feature name can be used) to indicate that the consumer (e.g., AMF 200) and the PCF 210 supports the notification procedure of that UE policy association is to be terminated to allow UE policies to first be removed from the UE before deleting the UE policy association due to UE subscription change indicating the UE policy association is changed from enabled to disabled.

[0121] Going back to step 3, when the AMF 200 needs to inform the PCF 210 that UE Policy Association needs to be terminated due to subscription change in UE policy association, the AMF 200 first updates the PCF 210 of the subscription change and sends Npcf UEPolicyControl Update request. The AMF includes a new Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change. For example, the new IE is “reqTermPolAssoc” in Policy AssociationUpdateRequest document or data structure as the request body of within the request message Npcf UEPolicyControl Update request as specified in 3GPP 5G standard. The embodiment herein can be incorporated in different sections of the standards as illustrated below:3GPP TS 29.525 Section 5.6.2.45.6.2.4 Type Policy AssociationUpdateRequestTable 5.6.2.4-1: Definition of type Policy AssociationUpdateRequest"""""" ""3GPP TS 29.525 Section 5.85.8 F eature negoti ati onThe optional features in table 5.8-1 are defined for the Npcf UEPolicyControl API. They shall be negotiated using the extensibility mechanism defined in clause 6.6 of 3GPP TS 29.500 [5],Table 5.8-1: Supported Features""

[0122] Step 4: The PCF 210 removes the UE policies in UE, if any, by sending an empty UE Policy container to the UE via the AMF 200 using existing UE policy delivery mechanism described in 3GPP TS 24.501, i.e., the obtained empty UE container being transmitted to the UE from AMF 200 in a NAS message.

[0123] Step 5: After removing any UE policies in UE if any were available, the PCF 210 uses Npcf_UEPolicyControl_UpdateNotify service operation to notify AMF 200 that the UE Policy Association can now be terminated.

[0124] Step 6: The AMF 200 deletes the UE Policy Association using Npcf UEPolicyControl Delete service operation, i.e., sends a Npcf UEPolicyControl Delete Request to the PCF210 to delete the UE policy association and receiving a response from PCF 210 indicating the UE policy association has been deleted.

[0125] End state: No UE Policy Association between AMF 200 and PCF 210 exists. The UE has no UE policy information (i.e., removed if any were available prior to the procedure). The UE Context in the AMF 200 has UE Policy Association (uePolicylnd) disabled.

[0126] Non-roaming: UE Policy Association exists

[0127] Figure 7b illustrate UE policy removal at the UE when UE policy association between AMF and PCF exists in accordance with some aspects.

[0128] Starting state: AMF has established UE Policy Association since initial UE subscription indicates UE Policy Association indicator = "enabled". The UE may have some UE policies. The UE is in state registered in AMF.

[0129] Step 1 : Operator changes uePolicylnd to "disabled". UE subscription is updated in UDR. Since it's a change from "enabled" to "disabled" of the uePolicylnd (UE policy indicator), a changeflag is also set.

[0130] Step 2: The AMF is notified by the UDM / UDR that UE Policy Association subscription is disabled for the UE. For example the UDM uses Nudm SDM Notification service operation to notify the AMF by including in the notification a UE Policy Association indicator = "disabled" (uePolicy!nd=false) and the flag ("changeflag) (since uePolicylnd is changed from "enabled1to 'disabled'. See Table 9-0 above.

[0131] Step 3 : Since a UE policy association already exists, the AMF informs the PCF that UE Policy Association needs to be terminated due to subscription change and thus provides the PCF the opportunity to remove any UE Policy in the UE. The AMF sends Npcf UEPolicyControl Update request and includes the new IE “reqTermPol Assoc” in Policy AssociationUpdateRequest document indicating the UE Policy Association needs to be terminated due to UE subscription change. The reqTermPol Assoc is further described in the table below based on modification of Policy AssociationUpdateRequest in 3GPP TS 29.525 Section 5.6.2.4Table 10-1: Definition of type Policy AssociationUpdateRequest"""""" ""

[0132] Step 4: The PCF removes the UE policies in UE, if any, by sending an empty UE Policy container to the UE using exiting UE policy delivery mechanism via the AMF as specified in 3GPP TS 24.501 and 3GPP TS 29.525.

[0133] Step 5: After removing any UE policy in the UE, the PCF uses for example Npcf_UEPolicyControl_UpdateNotify service operation to notify AMF that the UE Policy Association can now be terminated.

[0134] Step 6: The AMF then proceeds to delete the UE Policy Association using Npcf UEPolicyControl Delete service operation with PCF, i.e., request the PCF to terminate the UE policy association and receives a response from the PCF.

[0135] Step 7: The AMF acknowledges to UDM / UDR, by for example sending a notification or any appropriate message) comprising an indication to the effect that the necessary actions have been taken to release / terminate the UE policy association after removing any UE policies in the UE following the received changeflag . The UDM or UDRclears ‘changeflag’ and thus won’t notify AMF with ‘changeflag’ in subsequent registration for as long as the UE policy remains disabled.

[0136] End state: No UE Policy Association between AMF and PCF exists. UE has no UE policy. UE Context in AMF has UE Policy Association (uePolicylnd) disabled.

[0137] The disclosed embodiment as well as the following embodiments avoid the problems as described above. The AMF gives PCF the opportunity to remove UE Policies to the UE. PCF may initiate the removal of the UE Policies in the UE by invoking step 4 followed by requesting AMF to terminate UE Policy Association. UE policy associations at the UE can be removed in a save and effective manner.

[0138] Non-roaming: UE Policy Association does not exist

[0139] Figure 7c illustrate UE policy removal at the UE when UE policy association between AMF and PCF does not exist in accordance with some aspects.

[0140] Starting state: UE may have some UE policies. There is no existing UE Policy Association (since the UE is not registered in the network / AMF or is deregistered)

[0141] Step 0: Operator changes uePolicylnd to "disabled". UE subscription is updated in UDR. Since it's a change from "enabled" to "disabled" of the uePolicylnd (UE policy indicator), a changeflag is also set.

[0142] Step 1 : The UE registers to the AMF.

[0143] Step 2: AMF fetches AM subscription data (AM-DATA) from UDM / UDR. The AMF receives as part of the subscription data the uePolicylnd indicating "disabled" and a new flag ("changeflag) (since uePolicylnd is changed from "enabled1to 'disabled'. The following describes modification of AccessAndMobilitySubscriptiondata as specified in TS 29.503 section 6.1.6.2.4 to support the embodiments herein:Table 9-0: Definition of type AccessAndMobilitySubscriptionData

[0144] Step 3 : Because the AMF received the changeflag information, the AMF initiates creation of UE Policy Association, even though uePolicylnd-' Disabled". The AMF creates UE Policy Association and informs the PCF that UE Policy Association needs to be terminated due to subscription change and thus provides the PCF the opportunity to remove any UE Policy in the UE. The AMF sends Npcf UEPolicyControl Create request and includes the new IE "reqTermPolAssoc" in Policy AssociationUpdateRequest document indicating the UE Policy Association needs to be terminated due to UE subscription change. The reqTermPolAssoc is further described in the table below based on modification of Policy AssociationCreateRequest in 3GPP TS 29.525 Section 5.6.2.3:Table 9-1: Definition of type Policy AssociationCreateRequest"""""" ""

[0145] Step 4: The PCF removes the UE policies in UE, if any, by sending an empty UE Policy container to the UE using exiting UE policy delivery mechanism.

[0146] Step 5: Then PCF uses Npcf UEPolicyControl UpdateNotify service operation to notify AMF that the UE Policy Association can now be terminated.

[0147] Step 6: The AMF deletes the UE Policy Association using Npcf UEPolicyControl Delete service operation.

[0148] Step 7: The AMF acknowledges to UDM / UDR that necessary actions have been taken. The UDR clears ‘changeflag’ and thus won’t notify AMF with ‘changeflag’ in subsequent registration (unless the UEpolicy indicator is changed from “disable” to “enable” and to “disable” again.) .

[0149] End state: No UE Policy Association between the AMF and the PCF is established as it has been terminated. The UE has no UE policy. The UE Context in AMF has UE Policy Association indicator (uePolicylnd) set to disabled.

[0150] Roaming: AMF receives UE policy indicator indicating “Disabled”

[0151] Figure 8a illustrates the flow diagram for UE policy association termination for roaming scenario according to the embodiments herein.

[0152] Starting state: AMF has established UE Policy Association since UE subscription initially indicated the UE Policy Association is enabled (UE Policy indicator is set to true indicating "enabled". The UE may have some UE policies.

[0153] Step 1: Operator disables the UE policy association, for example changes UE Policy Association indicator to false indicating "disabled". The UE subscription comprising uePolicylnd is modified as the value of the indicator is modified. The UE subscription is also updated in UDR.

[0154] Step 2: The AMF 200 is notified by the UDM 206 / UDR in the home network that UE Policy Association is to be disabled for the UE. The UDM 206 uses Nudm SDM Notification service operation and include the UE Policy Association indicator set to false indicating UE policy association is disabled (uePolicy!nd=false).

[0155] Step 3. If UE Policy Association exists, the AMF 200 informs the Home PCF (H-PCF 210a) via the visited PCF (V-PCF 20b) that UE Policy Association needs to be terminated due to subscription change in UE policy association (uePolicylnd indicating UE policy association Is disabled). The AMF 200 thus provides the H-PCF 210a the opportunity to remove any UE Policy in the UE. In some embodiment, the AMF 200 may determine that it needs to first notify the H-PCF 210a via the V-PCF 210b that UE policy association is to be terminated to allow the H-PCF 210a to remove the UE policies at the UE before terminating the UE policy association based on feature negotiation with the H-PCF 210a and optionally V-PCF210b, i.e., AMF 200 and / or H-PCF 210a (and optionally V-PCF 210b) exchange the feature capability, referred herein as "TermNotif (albeit any feature name can be used) to indicate that the consumer (e.g., AMF 200) and the H-PCF 210a (and optionally V-PCF 210b) supports the notification procedure of that UE policy association is to be terminated to allow UE policies to first be removed from the UE before deleting the UE policy association due to UE subscription change indicating the UE policy association is changed from enabled to disabled. Going back to step 3, when the AMF 200 needs to inform the H-PCF 210a that UEPolicy Association needs to be terminated due to subscription change in UE policy association, the AMF 200 first updates the H-PCF 210a of the subscription change and sends Npcf UEPolicyControl Update request. The AMF 200 includes a new Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change. For example the new IE is "reqTermPolAssoc" in Policy AssociationUpdateRequest document or data structure as the request body of within the request message Npcf UEPolicyControl Update request as specified in 3GPP 5G standard. The embodiment herein can be incorporated in different sections of the standards as illustrated above in the tables in step 3 of Figure 7a above.

[0156] Step 4. The H-PCF 210a removes the UE policies in UE, if any, by sending an empty UE Policy container to the UE via the AMF 200 using existing UE policy delivery mechanism described in 3GPP TS 24.501, i.e., the obtained empty UE container being transmitted to the UE from AMF 200 in a NAS message.

[0157] Step 5. After removing any UE policies in UE if any were available, the H-PCF 210a uses Npcf_UEPolicyControl_UpdateNotify service operation to notify AMF 200 via the V-PCF 210b that the UE Policy Association can now be terminated.

[0158] Step 6. The AMF 200 deletes the UE Policy Association using Npcf UEPolicyControl Delete service operation, i.e., sends a Npcf UEPolicyControl Delete Request to the H-PCF210a via the V-PCF 210b to delete the UE policy association and receiving a response from the H-PCF 210a via the V-PCF 210b indicating the UE policy association has been deleted.

[0159] End state: No UE Policy Association between AMF 200 and H-PCF / V-PCF 210a / 210b exists. The UE has no UE policy information (i.e., removed if any were available prior to the procedure). The UE Context in the AMF 200 has UE Policy Association (uePolicylnd) disabled.

[0160] Non-roaming: UE Policy Association exists

[0161] Figure 8b illustrate UE policy removal at the UE when UE policy association between AMF and a home PCF exist in accordance with some aspects.

[0162] The steps in Figure 8b are similar to Steps in Figure 7b to the exception that the AMF communicates with the home PCF (H-PCF) via the Visited PCF (V-PCF). The H-PCF removes the UE policies from the UE before terminating the UE policy association.

[0163] Non-roaming: UE Policy Association does not exist

[0164] Figure 8c illustrate UE policy removal at the UE when UE policy association between AMF and a home PCF does not exist in accordance with some aspects.

[0165] The steps in Figure 8c are similar to Steps in Figure 7c to the exception that the AMF communicates with the home PCF (H-PCF) via the Visited PCF (V-PCF). The H-PCF removes the UE policies from the UE before terminating the UE policy association.

[0166] Feature negotiation

[0167] As the interaction between AMF and (H)PCF according to embodiments herein illustrated in any of the Figures above is also a proposed enhancement to the existing 5G standardized procedure of UE policy association termination, the optimization can be negotiated as a feature to maintain backward compatibility in already deployed system.

[0168] The optional features in table 12 are defined for the Npcf UEPolicyControl API. They shall be negotiated using the extensibility mechanism defined in clause 6.6 of 3GPP TS 29.500. When the AMF and (H)PCF negotiate the use of the feature “Termnotif’, the procedure enables that any remaining UE policies at the UE are always removed when UE policy association in the subscription is changed to “disabled”. The feature may be negotiated during establishment of the UE policy association between the AMF and (H)PCF or configured in the (H)PCF and AMF. Both AMF and (H)PCF must indicate the support of the feature in API request / response.Table 12: Supported Features""

[0169] Further Embodiments

[0170] Figure 9 is a schematic block diagram of a network node 1100 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 1100 may be, for example, a core network node that implements a NF (e.g., one or more of the 5G network functions, or the like, as described herein). As illustrated, the network node 1100 includes a one or more processors 1104 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and / or the like), memory 1106, and a network interface 1108. The one or more processors 1104 are also referred to herein as processing circuitry. The one or more processors 1104 operate to provide one or more functions of the network node 1100 as described herein (e.g., one or more functions of the e.g., one or more of the 5G network functions, or the like, as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 1106 and executed by the one or more processors 1104.

[0171] Figure 10 is a schematic block diagram that illustrates a virtualized embodiment of the network node 1100 according to some embodiments of the present disclosure. Again, optional features are represented by dashed boxes. As used herein, a “virtualized” network node is an implementation of the network node 1100 in which at least a portion of the functionality of the network node 1100 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 1100 includes one or more processing nodes 1200 coupled to or included as part of a network(s) 1202. Each processing node 1200 includes one or more processors 1204 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 1206, and a network interface 1208. In this example, functions 1210 of the network node 1100 described herein (e.g., one or more of the 5G network functions, or the like, as described herein) are implemented at the one or more processing nodes 1200 or distributed across the two or more processing nodes 1200 in any desired manner. In some particular embodiments, some or all of the functions 1210 of the network node 1100 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1200.

[0172] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 1100 or a node (e.g., a processing node 1200) implementing one or more of the functions 1210 of the network node 1100 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0173] Figure 11 is a schematic block diagram of the network node 1100 which may also be a radio access node 1100 according to some other embodiments of the present disclosure. The network node 1100 includes one or more modules 1300, each of which is implemented in software. The module(s) 1300 provide the functionality of the network node 1100 described herein. This discussion is equally applicable to the processing node 1200 of Figure 14 where the modules 1300 may be implemented at one of the processing nodes 1200 or distributed across multiple processing nodes 1200.

[0174] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0175] While processes in the figures (flow charts, procedures) may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0176] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

[0177] Features of any of the examples or embodiments outlined above may be combined to create additional examples or embodiments without losing the intended effect. It should be understood that the description of an embodiment or example provided above is by way of example only, and various modifications could be made by one skilled in the art. Furthermore, one skilled in the art will recognise that numerous further modifications and combinations of various aspects are possible. Accordingly, the described aspects are intended to encompass all such alterations, modifications, and variations that fall within the scope of the appended claims.

Claims

39CLAIMS1. A method performed by an access and mobility management function, AMF, the method comprising:sending to the policy function information to instruct the PCF to remove any User Equipment (UE) policies at the UE as a result of obtaining from a subscription data node a UE subscription data indicating the UE policy association is disabled;receiving a notification from the policy function that the UE policy association can be terminated; and - invoking a UE policy association delete service operation to delete the UE policy association in the policy function in response to the received notification.

2. The method of claim 1 wherein the access and mobility management function has a User Equipment (UE) policy association established with a policy function for a UE and wherein the information is a notification, a policy update or a policy control request trigger to indicate that the UE policy association is to be terminated that the UE policy association has been disabled, after obtaining a UE subscription change indicating the UE policy association is disabled.

3. The method of any one of claims 1 to 2, wherein the information comprises an Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change.

4. The method of any one of claims 1 to 3, wherein the IE is included inPolicy AssociationUpdateRequest document or data structure orPolicy AssociationCreateRequestdata document or data structure.

5. The method of any one of claims 1 to 4 wherein the IE is "reqTermPol Assoc".

406. The method of any one of claims 1 to 5 wherein the information is one of an Npcf UEPolicyControl Update request when UE policy association exists at the AMFor Npcf UEPolicyControl Create request when UE policy association does not yet exist for the UE at the AMF.

7. The method of any one of claims 1 to 6 wherein the UE subscription data indicating the UE policy association is disabled comprises a UE policy association indicator indicating UE policy association is disabled and may comprise a flag indicating the UE policy association is changed in the subscription data node from enabled to disabled.

8. The method of any one of claims 1 to 7 wherein prior to sending the information to the policy function, at least one of- checking that the policy function indicated support of a feature of receiving instruction to remove any User Equipment (UE) policies prior to terminating the UE policy association, and- checking that the access and mobility management function and policy function support the feature of sending and receiving respectively instruction to remove any User Equipment (UE) policies prior to terminating the UE policy association.

9. The method of claim 8 wherein the feature is negotiated during the UE policy association establishment.

10. A method performed by a policy function, the method comprising:receiving from an access and mobility management information to instruct the policy function to remove any User Equipment (UE) policies as a result of subscription data change indicating a UE policy association indicator set to disabled; - removing UE policies in the UE if any and sending a notification to the access and mobility management function to indicate that the UE policy association can be terminated, and - deleting any established UE policy association in response to receiving a request to delete UE policy association.4111. The method of claim 10, wherein the policy function has a User Equipment (UE) policy association established with an access and mobility management function for a UE and wherein the information is a notification, a policy update or a policy control request trigger to indicate that the UE policy association is to be terminated or that the UE policy association has been disabled.

11. The method of claim 10 wherein the information comprises an Information Element (IE) indicating the UE Policy Association needs to be terminated due to UE subscription change.

12. The method of any one of claims 10 to 11, wherein the IE is included in Policy AssociationUpdateRequest document / data structure or Policy AssociationCreateRequest document / data structure.

13. The method of any one of claims 10 to 12 wherein the IE is "reqTermPol Assoc".

14. The method of any one of claims 10 to 13 wherein the information is one of an Npcf UEPolicyControl Update request when UE policy association exists at the AMFor Npcf UEPolicyControl Create request when UE policy association do not yet exist for the UE at the AMF.

15. The method of any one of claims 10 to 14 wherein the method further comprises, checking whether a feature of notifying the AMF the UE policy association can be terminated after deletion of the UE policies in the UE, is supported.

16. The method of claim 15 wherein the feature is negotiated during the UE policy association establishment.

17. A network node configured to perform the method of any one of claims 1 to 16.

18. A network node comprising one or more processors and memory comprising instructions which when executed by the one or more processors enable the network node to perform the method of any one of the claims 1 to 16.

19. A computer readable memory comprising instructions which when executed by one or more processors of one or more servers configures the one or more servers to perform any one of the claims 1 to 16.

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