Enhancement on the smf selection based on subscription

Abstract

Systems and methods are disclosed herein that relate to Session Management Function (SMF) selection based on subscription data. In one embodiment, a method performed by first network node in a core network of a cellular communications system comprises sending, to a second network node, a request for SMF selection subscription data of a UE and receiving, from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising one or more SMF selection criteria and one or more conditions for applying the one or more SMF selection criteria. The method further comprises performing SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE. In this manner, improved SMF selection is provided.

Description

Applicant’s Ref. P108743WO01 1 ENHANCEMENT ON THE SMF BASED ON SUBSCRIPTION Technical Field

[0001] The present disclosure relates to a cellular communications system and, more specifically, to Session Management Function (SMF) selection in a 3rdGeneration Partnership Project (3GPP) network. Background

[0002] In a 3rdGeneration Partnership Project (3GPP) network, Session Management Function (SMF) selection requirements are specified in clause 6.3.2 of 3GPP Technical Specification (TS) 23.501 as shown in the following excerpt from 3GPP TS 23.501 V18.2.1. In the excerpt, bold text shows the information received from the Unified Data Management (UDM) as part of the User Equipment (UE) subscription data to be used by the Access and Mobility Management Function (AMF) as input for selection of a SMF for that UE. Note that this UE subscription data may also be referred to herein as “UE subscription data for SMF selection” or “the UE’s SMF Selection Subscription Data.” ***** Start Excerpt from 3GPP TS 23.501 V18.2.1 ***** 6.3.2 SMF discovery and selection The SMF selection functionality is supported by the AMF and SCP and is used to allocate an SMF that shall manage the PDU Session. The SMF selection procedures are described in clause 4.3.2.2.3 of TS 23.502 [3]. The SMF discovery and selection functionality follows the principles stated in clause 6.3.1. If the AMF does discovery, the AMF shall utilize the NRF to discover SMF instance(s) unless SMF information is available by other means, e.g. locally configured on AMF. The AMF provides UE location information to the NRF when trying to discover SMF instance(s). The NRF provides NF profile(s) of SMF instance(s) to the AMF. In addition, the NRF also provides the SMF service area of SMF instance(s) to the AMF. The SMF selection functionality in the AMF selects an SMF instance and an SMF service instance based on the available SMF instances obtained from NRF or on the configured SMF information in the AMF. NOTE 1: Protocol aspects of the access to NRF are specified in TS 29.510

[0058] . The SMF selection functionality is applicable to both 3GPP access and non-3GPP access. The SMF selection for Emergency services is described in clause 5.16.4.5. The following factors may be considered during the SMF selection: a) Selected Data Network Name (DNN). In the case of the home routed roaming, the DNN is not applied for the V- SMF selection. b) S-NSSAI of the HPLMN (for non-roaming and home-routed roaming scenarios), and S-NSSAI of the VPLMN (for roaming with local breakout and home-routed roaming scenarios). c) NSI-ID. NOTE 2: The use of NSI -ID in the network is optional and depends on the deployment choices of the operator. If used, the NSI ID is associated with S-NSSAI.Applicant’s Ref. P108743WO01 2 d) Access technology being used by the UE. e) Support for Control Plane CIoT 5GS Optimisation. f) Subscription information from UDM, e.g. - per DNN: whether LBO roaming is allowed. - per DNN: whether HR-SBO roaming is allowed. - per S-NSSAI: the subscribed DNN(s). - per (S-NSSAI, subscribed DNN): whether LBO roaming is allowed. - per (S-NSSAI, subscribed DNN): whether HR-SBO roaming is allowed. - per (S-NSSAI, subscribed DNN): whether EPC interworking is supported. - per (S-NSSAI, subscribed DNN): whether selecting the same SMF for all PDU sessions to the same S- NSSAI and DNN is required. - per (S-NSSAI, DNN) associated with 5G VN group: Service Area (LADN service area) for the 5G VN group. In the case of SMF selection for a PDU Session targeting 5G VN group, the AMF may prefer candidate SMF(s) that have an intersection with the LADN service area of the 5G VN group. g) Void. h) Local operator policies. NOTE 3: These policies can take into account whether the SMF to be selected is an I-SMF or a V-SMF or a SMF. i) Load conditions of the candidate SMFs. j) Analytics (i.e. statistics or predictions) for candidate S’Fs' load as received from NWDAF (see TS 23.288

[0086] ), if NWDAF is deployed. k) UE location (i.e. TA). l) Service Area of the candidate SMFs. m) Capability of the SMF to support a MA PDU Session. n) If interworking with EPS is required. o) Preference of V-SMF support. This is applicable only for V-SMF selection in the case of home routed roaming. p) Target DNAI. q) Capability of the SMF to support User Plane Remote Provisioning (see clause 5.30.2.10.4.3). r) Supported DNAI list. s) HR-SBO support (according to clause 6.7 of TS 23.548

[0130] ). t) Capability of the SMF (V-SMF and H-SMF) to support non-3GPP access path switching. To support the allocation of a static IPv4 address and / or a static IPv6 prefix as specified in clause 5.8.2.2.1, a dedicated SMF may be deployed for the indicated combination of DNN and S-NSSAI and registered to the NRF, or provided by the UDM as part of the subscription data. In the case of delegated discovery, the AMF, shall send all the available factors a)-d), k) and n) to the SCP.Applicant’s Ref. P108743WO01 3 In addition, the AMF may indicate to the SCP which use (in the case of NRF dedicated to the target slice). If there is an existing PDU Session and the UE requests to establish another PDU Session to the same DNN and S- NSSAI of the HPLMN, and the UE subscription data indicates the support for interworking with EPS for this DNN and S-NSSAI of the HPLMN or UE subscription data indicates the same SMF shall be selected for all PDU sessions to the same S-NSSAI, DNN, the same SMF in non roaming and LBO case or the same H-SMF in home routed roaming case, shall be selected. In addition, if the UE Context in the AMF provides a SMF ID for an existing PDU session to the same DNN, S-NSSAI, the AMF uses the stored SMF ID for the additional PDU Session. In any such a case where the AMF can determine which SMF should be selected, if delegated discovery is used, the AMF shall indicate a desired NF Instance ID so that the SCP is able to route the message to the relevant SMF. Otherwise, if UE subscription data does not indicate the support for interworking with EPS for this DNN and S-NSSAI, a different SMF in non roaming and LBO case or a different H-SMF in home routed roaming case, may be selected. For example, to support a SMF load balancing or to support a graceful SMF shutdown (e.g. a SMF starts to no more take new PDU Sessions). In the home-routed roaming case, the SMF selection functionality selects an SMF in VPLMN based on the S-NSSAI of the VPLMN, as well as an SMF in HPLMN based on the S-NSSAI of the HPLMN. This is specified in clause 4.3.2.2.3.3 of TS 23.502 [3]. If the HR-SBO roaming is allowed for the PDU Session, the DNN is also considered for V-SMF selection. When the UE requests to establish a PDU Session to a DNN and an S-NSSAI of the HPLMN, if the UE MM Core Network Capability indicates the UE supports EPC NAS and optionally, if the UE subscription indicates the support for interworking with EPS for this DNN and S-NSSAI of the HPLMN, the selection functionality (in AMF or SCP) selects a combined SMF+PGW-C. Otherwise, a standalone SMF may be selected. If the UDM provides a subscription context that allows for handling the PDU Session in the VPLMN (i.e. using LBO) for this DNN and S-NSSAI of the HPLMN and, optionally, the AMF is configured to know that the VPLMN has a suitable roaming agreement with the HPLMN of the UE, the following applies: - If the AMF does discovery, the SMF selection functionality in AMF selects an SMF from the VPLMN. - If delegated discovery is used, the SCP selects an SMF from the VPLMN. If an SMF in the VPLMN cannot be derived for the DNN and S-NSSAI of the VPLMN, or if the subscription does not allow for handling the PDU Session in the VPLMN using LBO, then the following applies: - If the AMF does discovery, both an SMF in VPLMN and an SMF in HPLMN are selected, and the DNN and S- NSSAI of the HPLMN is used to derive an SMF identifier from the HPLMN. - If delegated discovery is used: - The AMF performs discovery and selection of H-SMF from NRF. The AMF may indicate the maximum number of H-SMF instances to be returned from NRF, i.e. SMF selection at NRF. - The AMF sends Nsmf_PDUSession_CreateSMContext Request to SCP, which includes the endpoint (e.g. URI) of the selected H-SMF, and the discovery and selection parameters as defined in this clause, i.e. parameter for V-SMF selection. The SCP performs discovery and selection of the V-SMF and forwards the request to the selected V-SMF. - The V-SMF sends the Nsmf_PDUSession_Create Request towards the H-SMF via the SCP; the V-SMF uses the received endpoint (e.g. URI) of the selected H-SMF to construct the target destination to be addressed. The SCP forwards the request to the H-SMF. - Upon reception of a response from V-SMF, based on the received V-SMF ID the AMF obtains the Service Area of the V-SMF from NRF. The AMF uses the Service Area of the V-SMF to determine the need for V- SMF relocation upon subsequent UE mobility. If the initially selected SMF in VPLMN (for roaming with LBO) detects it does not understand information in the UE request, it may reject the N11 message (related with a PDU Session Establishment Request message) with a proper N11Applicant’s Ref. P108743WO01 4 cause triggering the AMF to select both a new SMF in and a SMF in the HPLMN (for home routed roaming). The AMF selects SMF(s) considering support for CIoT 5GS optimisations (e.g. Control Plane CIoT 5GS Optimisation). In the case of onboarding of UEs for SNPNs, when the UE is registered for SNPN onboarding the AMF selects SMF(s) of Onboarding Network considering the Capability of SMF to support User Plane Remote Provisioning. Additional details of AMF selection of an I-SMF are described in clause 5.34. In the case of home routed scenario, the AMF selects a new V-SMF if it determines that the current V-SMF cannot serve the UE location. The selection / relocation is same as an I-SMF selection / relocation as described in clause 5.34. ***** End Excerpt from 3GPP TS 23.501 V18.2.1 *****

[0003] The UE’s SMF Selection Subscription Data is specified in 3GPP TS 29.503 as shown in the following excerpts from 3GPP TS 29.503 V18.2.0, where the AMF can retrieve the ‘UE's SMF Selection Subscription Data(SmfSelectionSubscriptionData) which further contains Single Network Slice Selection Assistance Information (S- NSSAI) Information (SnssaiInfo) containing Data Network Name (DNN) Information (DnnInfo). Relevant portion of the excerpts are emphasis with bold text ***** Start First Excerpt from 3GPP TS 29.503 V18.2.0 ***** Figure 1 5.2.2.2.4 SMF Selection Subscription Data RetrievalFigure 5.2.2.2.4-1 shows a scenario where the NF service consumer (e.g. AMF) sends a request to the UDM toreceive the’UE's SMF Selection Subscription data (see also 3GPP TS 23.502 [3] figure 4.2.2.2.2-1 step 14). The request contains the’UE's identity ( / {supi}), the type of the requested information ( / smf-select-data) and query parameters (supported-features, plmn-id). [REPRODUCED HEREIN AS FIGURE 1] Figure 5.2.2.2.4-1: Requesting a UE’s SMF Selection Subscription Data 1. The NF service consumer (e.g. AMF) sends a GET request to the resource representing the UE’s SMF Selection Subscription Data, with query parameters indicating the supported-features and / or plmn-id. 2a. On success, the UDM responds with “200 OK” with the message body containing the UE’s SMF Selection Subscription Data as relevant for the requesting NF service consumer.2b. If there is no valid subscription data for the UE, HTTP status code “404 Not Found” shall be returned including additional error information in the response body (in the “ProblemDetails” element). On failure, the appropriate HTTP status code indicating the error shall be returned and appropriate additional error information should be returned in the GET response body. ***** Start Second Excerpt from 3GPP TS 29.503 V18.2.0 *****Applicant’s Ref. P108743WO01 5 6.1.3.6 Resource: (Document) 6.1.3.6.1 Description This resource represents the subscribed SMF Selection Data for a SUPI. It is queried by the AMF after registering. 6.1.3.6.2 Resource DefinitionResource URI: {apiRoot} / nudm-sdm / <apiVersion> / {supi} / smf-select-dataThis resource shall support the resource URI variables defined in table 6.1.3.6.2-1. Table 6.1.3.6.2-1: Resource URI variables for this resource Name Data type Definition apiRoot string See clause 6.1.1 supi Supi Represents the Subscription Permanent Identifier (see 3GPP TS 23.501 [2] clause 5.9.2) pattern: See pattern of type Supi in 3GPP TS 29.571 [7] 6.1.3.6.3 Resource Standard Methods 6.1.3.6.3.1 GET This method shall support the URI query parameters specified in table 6.1.3.6.3.1-1. Table 6.1.3.6.3.1-1: URI query parameters supported by the GET method on this resource Name Data type P Cardinality Description supported-features SupportedFeatures O 0..1 see 3GPP TS 29.500 [4] clause 6.6 plmn-id PlmnId O 0..1 PLMN identity of the PLMN serving the UE disaster-roaming- boolean O 0..1 Disaster Roaming Indicator (see 3GPP TS 23.502 [3]). ind When present, this IE shall be set as follows: - true: Disaster Roaming service is applied; - false (default): Disaster Roaming service is not applied. If “plmn-id” is included, UDM shall return the SMF Selection Subscription Data for the SUPI associated to the PLMN identified by “plmn-id”. If “plmn-id” is not included, UDM shall return the SMF Selection Subscription Data for the SUPI associated to the HPLMN. This method shall support the request data structures specified in table 6.1.3.6.3.1-2 and the response data structures and response codes specified in table 6.1.3.6.3.1-3. Table 6.1.3.6.3.1-2: Data structures supported by the GET Request Body on this resource Data type P Cardinality Description n / aApplicant’s Ref. P108743WO01 6 Table 6.1.3.6.3.1-3: Data structures by the GET Response Body on this resource Data type P Cardinality Response Description codes SmfSelectionSubsc M 1 200 OK Upon success, a response body containing the SMF riptionData Selection Subscription Data shall be returned. ProblemDetails O 0..1 404 Not The “cause” attribute may be used to indicate one of the Found following application errors: - USER_NOT_FOUND - DATA_NOT_FOUND NOTE: In addition common data structures as listed in table 5.2.7.1-1 of 3GPP TS 29.500 [4] are supported. Table 6.1.3.6.3.1-4: Headers supported by the GET method on this resource Name Data type P Cardinality Description If-None-Match string O 0..1 Validator for conditional requests, as described in IETF RFC 7232

[0025] , clause 3.2 If-Modified-Since string O 0..1 Validator for conditional requests, as described in IETF RFC 7232

[0025] , clause 3.3 Table 6.1.3.6.3.1-5: Headers supported by the 200 Response Code on this resource Name Data type P Cardinality Description Cache-Control string O 0..1 Cache-Control containing max-age, as described in IETF RFC 7234

[0026] , clause 5.2 ETag string O 0..1 Entity Tag, containing a strong validator, as described in IETF RFC 7232

[0025] , clause 2.3 Last-Modified string O 0..1 Timestamp for last modification of the resource, as described in IETF RFC 7232

[0025] , clause 2.2Applicant’s Ref. P108743WO01 7 ***** Start Third Excerpt 3GPP TS 29.503 V18.2.0 ***** 6.1.6.2.5 Type: SmfSelectionSubscriptionData Table 6.1.6.2.5-1: Definition of type SmfSelectionSubscriptionData Attribute Data type P Cardinality Description Applicability name supportedFe SupportedFeatures O 0..1 See clause 6.1.8 atures subscribedSn map(SnssaiInfo) O 0..N List of S-NSSAIs and associated information ssaiInfos (DNN Info); see 3GPP TS 23.501 [2] clause 6.3.2. A map (list of key-value pairs where singleNssai converted to string serves as key; see 3GPP TS 29.571 [7]) of arrays of DnnInfo sharedSnssai SharedDataId O 0..1 Identifier of shared SnssaiInfos. SharedData InfosId hssGroupId NfGroupId O 0..1 Identity of the HSS group associated with the subscription, which may be used by the UDM in discovering the HSS; see 3GPP TS 29.510

[0019] . May be present on the Nudr interface if there is DNN interworking with EPC and shall not be included over the Nudm interface. NOTE: A single UE-individual subscribedSnssaiInfo (within subscribedSnssaiInfos) may clash with a sharedSnssaiInfo (i.e. both have the same singleNssai value as key). In this case the UE- individual subscribedSnssaiInfo takes precedence unless treatment instructions associated to the shared data indicate otherwise. 6.1.6.2.6 Type: DnnInfo Table 6.1.6.2.6-1: Definition of type DnnInfo Attribute name Data type P Cardinality Description dnn Dnn M 1 Data Network Name with Network Identifier only., or Wildcard DNN (NOTE) defaultDnnIndicator DefaultDnnIndica O 0..1 Indicates whether this DNN is the default DNN: tor true: The DNN is the default DNN (NOTE); false: The DNN is not the default DNN; If this attribute is absent it means the DNN is not the default DNN. lboRoamingAllowed LboRoamingAllo O 0..1 Indicates whether local breakout for the DNN is wed allowed when roaming: true: Allowed; false: Not allowed; If this attribute is absent it means not allowed. iwkEpsInd IwkEpsInd O 0..1 Indicates whether interworking with EPS is subscribed: true: Subscribed; false: Not subscribed; If this attribute is absent it means not subscribed. dnnBarred boolean C 0..1 Indicates whether the DNN is barred. Absence and false indicates “not barred”. This attribute is only used on the Nudr interface. The UDM shall handle barred DNNs received from the UDR as not subscribed. invokeNefInd boolean O 0..1 Indicates whether the NEF based infrequent small data transfer shall be used for the PDU Session associated with the S-NSSAI and DNN.Applicant’s Ref. P108743WO01 8 True: Used; false: Not used; If this attribute is absent it means not used. smfList array(NfInstanceI O 1..N Indicate the associated SMF(s) if the static IP d) address / prefix is used. sameSmfInd boolean O 0..1 Indicates whether the same SMF for multiple PDU sessions to the same DNN and S-NSSAI is required. True: Required; false: Not required; If this attribute is absent it means not required. hrSboAllowed boolean O 0..1 Indicates whether Session Breakout for HR Session in VPLMN is allowed (see 3GPP TS 23.502 [3] and 3GPP TS 23.548

[0060] ). true: Allowed; false: Not allowed; If this attribute is absent it means not allowed. ladnServiceArea array(Tai) O 1..N Indicates the LADN Service Area. NOTE: If the dnn attribute contains the value of the Wildcard DNN (“*”), the defaultDnnIndicator shall not be set to true. 6.1.6.2.7 Type: SnssaiInfo Table 6.1.6.2.7-1: Definition of type SnssaiInfo Attribute name Data type P Cardinality Description dnnInfos array(DnnInfo) M 1..N list of Data Network Names for an S-NSSAI and associated information ***** End Excerpt from 3GPP TS 29.503 V18.2.0 ***** Summary

[0004] Systems and methods are disclosed herein that relate to Session Management Function (SMF) selection based on subscription data. In one embodiment, a method performed by first network node in a core network of a cellular communications system comprises sending, to a second network node, a request for SMF selection subscription data of a UE and receiving, from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising one or more SMF selection criteria and one or more conditions for applying the one or more SMF selection criteria. The method further comprises performing SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE. In this manner, improved SMF selection is provided.

[0005] In one embodiment, the one or more SMF selection criteria comprise any one or more of the following: information that indicates a target PLMN for SMF selection, information that indicates an SMF NF instance for SMF selection, information that indicates a SMF NF service set for SMF selection, information that indicates an SMF NF set for SMF selection, or information that indicates a locality for SMF selection.

[0006] In one embodiment, the one or more conditions for applying the one or more SMF selection criteria comprise one or more spatial (i.e., geographical) conditions for applying the one or more SMF selection criteria.Applicant’s Ref. P108743WO01 9

[0007] In one embodiment, the one or more for applying the one or more SMF selection criteria comprise one or more time-based conditions for applying the one or more SMF selection criteria.

[0008] In one embodiment, the method further comprises determining that the one or more conditions for applying the one or more SMF selection criteria are satisfied, wherein performing SMF selection for the PDU session of the UE comprises performing SMF selection for the PDU session based on the SMF selection criteria responsive to determining that the one or more conditions for applying the one or more SMF selection criteria are satisfied.

[0009] In one embodiment, performing SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE comprises sending, to a third network node, a discovery request comprising at least one query parameter that correspond to at least one of the one or more SMF selection criteria and receiving, from the third network node, a response to the discovery request, the response comprising information that identifies one or more candidate SMFs that satisfy the discovery request. In one embodiment, the third network node is a Network Repository Function (NRF). In one embodiment, performing SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE further comprises selecting a SMF from the one or more candidate SMFs. In one embodiment, the selected SMF is in a Public Land Mobile Network (PLMN) other than a PLMN of the AMF. In one embodiment, the method further comprises selecting a Visited SMF (V-SMF) in the PLMN of the AMF and sending a create session management (SM) context request towards the selected V-SMF, the create SM context request comprising information that indicates the selected SMF in the PLMN other than the PLMN of the AMF as a Home SMF (H-SMF).

[0010] In one embodiment, the first network node is an Access and Mobility Management Function (AMF).

[0011] In one embodiment, the second network node is a Unified Data Management (UDM) network function.

[0012] Corresponding embodiment of a first network node are also disclosed.

[0013] Embodiments of a method performed by a second network node are also disclosed. In one embodiment, a method performed by second network node in a core network of a cellular communications system comprises receiving, from a first network node, a request for SMF selection subscription data of a UE and sending, to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising one or more SMF selection criteria and one or more conditions for applying the one or more SMF selection criteria.

[0014] Corresponding embodiments of a second network node are also disclosed. Brief Description of the Drawings

[0015] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure. Figure 1 is a reproduction of Figure 5.2.2.2.4-1 from 3GPP TS 29.503 V18.2.0.Applicant’s Ref. P108743WO01 10 Figure 2 illustrates one example of a cellular system in which embodiments of the present disclosure may be implemented. Figure 3 illustrates a wireless communication system represented as a Fifth Generation (5G) network architecture composed of core Network Functions (NFs). Figure 4 illustrates an example of a roaming 5G network architecture. Figure 5 illustrates a Session Management Function (SMF) selection procedure in accordance with one example embodiment of the present disclosure. Figure 6 is a schematic block diagram of a network node according to some embodiments of the present disclosure. Figure 7 is a schematic block diagram that illustrates a virtualized embodiment of the network node according to some embodiments of the present disclosure. Figure 8 is a schematic block diagram of the network node according to some other embodiments of the present disclosure. Figure 9 is a schematic block diagram of a wireless communication device according to some embodiments of the present disclosure. Figure 10 is a schematic block diagram of the wireless communication device according to some other embodiments of the present disclosure. Detailed Description

[0016] 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.

[0017] Radio Node: As used herein, a “radio node” is either a radio access node or a wireless communication device.

[0018] 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.Applicant’s Ref. P108743WO01 11

[0019] Core Network Node: As used herein, a node” is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), 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), or the like.

[0020] 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 consumer electronic, 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.

[0021] 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 (IoT) 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.

[0022] 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.

[0023] Note that the description given herein focuses on a 3GPP 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.

[0024] 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.

[0025] There currently exist certain challenge(s). In an example connected car service deployed in a 3GPP 4thGeneration (4G) network / NSA, a cellular network of United States Operator A operates a Home Public Land Mobile Network (HPLMN) for an automobile sold in Canada. There are two configured APNs in the automobile for differentApplicant’s Ref. P108743WO01 12 functions (e.g., one APN for Telematics and another APN data connectivity). Instead of purchasing a data plan from United States Operator A, automobile owners in Canada may have the option to purchase a data plan from Canadian Operator B. Further, an automobile vendor may have a business relationship with United States Operator A, and the automobile vendor’s automobiles always use SUPIs / IMSIs in a particular range (e.g., [310-170]) for offering the connectivity service. These automobiles will be using somewhat permanent outbound roaming with the Canadian Operator B’s network when they are in Canada most of the time. The automobile’s UE has separate DNNs (APNs) for different functions (e.g., Telematics, data connectivity, etc.). While the automobile is in Canada, the automobile’s UE connects to Canadian Operator B’s network as outbound roamer and uses their gateway to reach their local program for streaming or Over-The-Top (OTT) provider, etc. However, when the automobile is driven into the United States and since the automobile’s UE has a SUPI of the United States Operator in the particular range (e.g., [310-170]), then the automobile’s UE connects to United States Operator A’s network as a home subscriber. The data connectivity specific APN Operator Identity (APN-OI) is replaced with Canadian Operator B’s APN-OI based on Home Subscriber Server (HSS) provisioning, and this replacement occurs in the MME. Due to this API-OI replacement, the data connectivity APN traffic of the automobile’s UE will be diverted to Canadian Operator B’s gateway (GW) instead of the local United States Operator A’s GW. The main driver for diverting the data connectivity traffic to Canadian Operator B’s GW is to get the local Canadian program for streaming and OTT provider data pertaining to that local Canada country for Canadian customer experience (who drives the automobile in US during the short visit). In that case, APN-OI replacement is currently being used to redirect the data connectivity connection to Canadian Operator B’s network instead of home route to United States Operator A’s network. However, there is a need to ensure that the service continues to work when upgraded to the 5G System Architecture (SA).

[0026] Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. To address the above example use case for selection of a SMF for a UE having a SUPI in a specific range (e.g., [310-170]), an enhanced subscription based SMF selection mechanism is needed, e.g., for UEs having a SUPI in a specific range (e.g., [310-170]). It can be envisioned that a specific SMF (or set of SMFs) may be selected, e.g., SMFs with high processing capacity and resilience, e.g. for UE in certain categories, or SMFs in a specific locality (e.g. in San Francisco), where such selection of a SMF may be associated with a spatial condition, e.g. such SMF selection criteria is valid only for a certain location where the UE is current registered; or a time condition, e.g. such SMF selection criteria is valid only for week days, not for weekend.

[0027] Systems and methods are disclosed that utilize an enhancement to the UE’s SMF Selection Subscription Data for SMF selection. The enhanced SMF Selection Subscription Data of the UE includes new information that is referred to herein by the exemplary name "enhanced SMF selection criteria.” Note, however, that this new information may be called by any desired name. In one embodiment, the new information contains a spatial (i.e., geographical) condition(s) and / or a time condition(s) to apply enhanced SMF selection criteria.Applicant’s Ref. P108743WO01 13

[0028] In one embodiment, the new information in the UE’s SMF Selection Subscription Data includes any one or any combination of two or more of the following parameters: • Parameter 1: A parameter that indicates a target PLMN. In one embodiment, the parameter that indicates the target PLMN contains, e.g., a PLMN ID including Mobile Country Code (MCC) + Mobile Network Code (MNC) or, in the case of a Stand-alone Non-Public Network (SNPN) a SNPN ID (PLMN ID + Network Identifier (NID)), so that the AMF is required to select a SMF anchor in the specific PLMN or in a SNPN identified by the target PLMN by using " target-plmn-list" containing the target PLMN SMF NF when performing NRF based SMF selection. o In one embodiment, from the AMF point of view, it should ignore the MCC and MNC included in the SUPI, and consider the SMF as a Home SMF where the AMF needs to select a Visited SMF (V-SMF) when the Serving Network of the AMF is different from the target PLMN (e.g., when Canada automobile user is "roaming" in United States), or consider the SMF as in a non-roaming scenario, i.e. when the AMF has the same PLMN as the SMF (e.g., when Canada automobile user is in Canada). The AMF may ignore the setting of "lboRoamingAllowed" for controlling local breakout. • Parameter 2: A parameter that includes a SMF NF (service) instance ID or SMF NF service set ID or SMF NF Set ID, to request that the AMF select a (specific) SMF service instance by using SMF NF (service) instance ID and / or SMF NF (service) ID when performing NRF based SMF selection. • Parameter 3: A parameter that indicates a locality, to request that the AMF use, e.g., "ext-preferred-locality" to find a SMF in a specific locality. • Parameter 4: A parameter that includes one or more spatial conditions (also referred to herein as one or more geographical conditions), to request that the AMF applies the above SMF selection criteria only when the UE is a certain location (i.e., a geographical location that satisfies the one or more spatial conditions). • Parameter 5: A parameter that includes one or more time-based conditions, to request that the AMF applies the above SMF selection criteria only when the time condition is satisfied. Figure 2

[0029] Figure 2 illustrates one example of a cellular communications system 200 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 200 is a 5G system (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC); however, the present disclosure is not limited to the 5GS and may be used in other (e.g., future) cellular communications system such as, e.g., the EPS or 6thGeneration (6G) system. In this example, the RAN includes base stations 202-1 and 202-2, 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 204-1 and 204-2. The base stations 202-1 and 202-2 are generally referred to herein collectively as base stations 202 and individually as base station 202. Likewise, the (macro) cells 204-1 and 204-2 are generally referred to herein collectively as (macro) cells 204 and individually as (macro) cell 204. The RANApplicant’s Ref. P108743WO01 14 may also include a number of low power nodes 206-1 206-4 controlling corresponding small cells 208-1 through 208-4. The low power nodes 206-1 through 206-4 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 208-1 through 208-4 may alternatively be provided by the base stations 202. The low power nodes 206-1 through 206-4 are generally referred to herein collectively as low power nodes 206 and individually as low power node 206. Likewise, the small cells 208-1 through 208-4 are generally referred to herein collectively as small cells 208 and individually as small cell 208. The cellular communications system 200 also includes a core network 210, which in the 5GS is referred to as the 5GC. The base stations 202 (and optionally the low power nodes 206) are connected to the core network 210.

[0030] The base stations 202 and the low power nodes 206 provide service to wireless communication devices 212-1 through 212-5 in the corresponding cells 204 and 208. The wireless communication devices 212-1 through 212-5 are generally referred to herein collectively as wireless communication devices 212 and individually as wireless communication device 212. In the following description, the wireless communication devices 212 are oftentimes UEs, but the present disclosure is not limited thereto. Figure 3

[0031] Figure 3 illustrates a 5G network architecture, which can be understood as one example embodiment of the cellular communications system 200 of Figure 2. As illustrated, from the access side, the 5G network architecture shown in Figure 3 includes UEs 212 connected to a RAN 202 or Access Network (AN) as well as an AMF 300. Typically, the R(AN) 202 comprises base stations, e.g., such as eNBs or gNBs or similar. Seen from the core network side, the 5GC NFs shown in Figure 3 include the AMF 300, UPF 302, NSSAAF 304, AUSF 306, SMF 308, SCP 310, NSACF 312, NSSF 314, NEF 316, NRF 318, PCF 320, UDM 322, AF 324, and EASDF 326.

[0032] 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. Figure 4

[0033] Figure 4 illustrates an example 5G roaming architecture for the home routed scenario, which can be understood as another example embodiment of the cellular communications system 200 of Figure 2. While not numbered, the elements in the Home Public Land Mobile Network (HPLMN) are sometimes referenced herein by the reference number of the corresponding element in Figure 3 but with “-H” appended to the reference number. Likewise, the elements in the Visited Public Land Mobile Network (VPLMN) are sometimes referenced herein by the reference number of the corresponding element in Figure 3 but with “-V” appended to the reference number. For example, the UPF in the VPLMN may be referenced herein as UPF 302-V (or visited UPF 302-V), whereas the UPF in the HPLMN may be referenced herein as UPF 302-H (or home UPF 302-H).Applicant’s Ref. P108743WO01 15 Figure 5

[0034] Figure 5 illustrates an SMF selection procedure in accordance with one example embodiment of the present disclosure. As illustrated, the steps of the procedure are as follows. Note, however, that while the actions are referred to as “steps”, these actions or steps are not limited to being performed in the order illustrated in Figure 5. These actions or steps may be performed in any suitable order and some of the actions or steps may be performed simultaneously. Also note that optional steps are represented in Figure 5 by dashed lines / boxes.

[0035] Step 500: The UE performs a registration procedure, e.g., as specified in 3GPP TS 23.502, clause 4.2.2.2.2.

[0036] Step 502: The AMF sends a request to the UDM for SMF selection data, e.g., as specified in clause 3GPP TS 23.502, clause 4.2.2.2.2, step 14b.

[0037] Step 504: In response, the UDM returns the requested SMF selection data to the AMF. The SMF selection data requested and received from the UDM includes the UE’s SMF Selection Subscription Data, which includes new information. As described above, this new information includes enhanced SMF selection criteria as described above and, in some embodiments, one or more spatial (i.e., geographical) conditions and / or one or more time conditions for applying the enhanced SMF selection criteria. As described above, in one embodiment, the new information includes any one or any combination of two or more of the following parameters: • Parameter 1: A parameter that indicates a target PLMN. In one embodiment, the parameter that indicates the target PLMN contains, e.g., a PLMN ID including Mobile Country Code (MCC) + Mobile Network Code (MNC) or, in the case of a Stand-alone Non-Public Network (SNPN) a SNPN ID (PLMN ID + Network Identifier (NID)), so that the AMF is required to select a SMF anchor in the specific PLMN or in a SNPN identified by the target PLMN by using " target-plmn-list" containing the target PLMN SMF NF when performing NRF based SMF selection. o In one embodiment, from the AMF point of view, it should ignore the MCC and MNC included in the SUPI, and consider the SMF as a Home SMF where the AMF needs to select a Visited SMF (V-SMF) when the Serving Network of the AMF is different from the target PLMN (e.g., when Canada automobile user is "roaming" in United States), or consider the SMF as in a non-roaming scenario, i.e. when the AMF has the same PLMN as the SMF (e.g., when Canada automobile user is in Canada). The AMF may ignore the setting of "lboRoamingAllowed" for controlling local breakout. • Parameter 2: A parameter that includes a SMF NF (service) instance ID or SMF NF service set ID or SMF NF Set ID, to request that the AMF select a (specific) SMF service instance by using SMF NF (service) instance ID and / or SMF NF (service) ID when performing NRF based SMF selection. • Parameter 3: A parameter that indicates a locality, to request that the AMF use, e.g., "ext-preferred-locality" to find a SMF in a specific locality.Applicant’s Ref. P108743WO01 16 • Parameter 4: A parameter that includes one or more spatial conditions (also referred to herein as one or more geographical conditions), to request that the AMF applies the above SMF selection criteria only when the UE is a certain location (i.e., a geographical location that satisfies the one or more spatial conditions). • Parameter 5: A parameter that includes one or more time-based conditions, to request that the AMF applies the above SMF selection criteria only when the time condition is satisfied.

[0038] In the illustrated example, the SMF selection data received by the AMF from the UDM is in the form of SmfSelectionSubscriptionData, which includes S-NSSAI Information (i.e., SnssaiInfo(s)) containing DNN Information (i.e., DnnInfo(s)), where a new data type “enhanced SMF selection criteria” is included in the DNN Information. The enhanced SMF selection criteria includes any one or more of the parameters described above.

[0039] It should be noted that, in some embodiment, the new information described above is only included in the SMF Selection Subscription Data of certain UEs such as, e.g., UEs having SUPIs or corresponding ISMIs that are within a certain set or range of SUPIs / IMSIs.

[0040] Step 505: In embodiments in which the new information included in the UE’s SMF Selection Subscription Data includes one or more spatial (i.e., geographical) conditions (e.g., Parameter 4 above) and / or one or more time- based conditions (e.g., Parameter 5 above) for applying the enhanced SMF selection criteria (e.g., Parameter 1, 2, and / or 3 above), the AMF determines whether the spatial condition(s) and / or time-based condition(s) for applying the enhanced SMF selection criteria are satisfied. If so, the enhanced SMF selection criteria are to be applied for SMF selection and, as such, the procedure proceeds as described below. However, if the spatial and / or time-based condition(s) are not satisfied, the AMF performs SMF selection without the enhanced SMF selection criteria (e.g., in the conventional manner).

[0041] Steps 506 and 508: Assuming the spatial and / or time-based condition(s) (if any) for applying the enhanced SMF selection criteria are satisfied, the AMF then uses the received SMF selection data including the enhanced SMF selection criteria indicated in the UE’s SMF Selection Subscription Data (e.g., the SmfSelectionSubscriptionData) for SMF selection. More specifically, in this example, the AMF sends a discovery request (i.e., an Nnrf_NFDiscovery GET request in this example) to the NRF, where the discovery request includes one or more query parameters corresponding to the enhanced SMF selection criteria (e.g., to set “target-plmn-list” to the target PLMN) (step 506). The NRF returns a list of candidate SMFs that satisfy the discovery request (step 508).

[0042] Step 510: The AMF selects an SMF from the list of candidate SMFs returned by the NRF. If the selected SMF is in a PLMN other than the serving PLMN of the AMF, the AMF selects a V-SMF. The AMF invokes the Nsmf_PDUSession service to send a Create SM Context Request towards the selected V-SMF, including the selected SMF as the H-SMF.

[0043] Step 512: The V-SMF invokes, or sends, a Nsmf_PDUSessionCreate Request to the H-SMF (i.e., the SMF selected by the AMF) to create the PDU session in the H-SMF.

[0044] Step 514: The H-SMF creates the PDU session and responds to the V-SMF.Applicant’s Ref. P108743WO01 17

[0045] Step 516: The V-SMF creates the SM the PDU session and responds to the AMF.

[0046] One example implementation of at least some aspects of the embodiments described herein can be expressed as changes to 3GPP TS 29.503 as shown below. Additions are shown by bold, underlined text. ***** Proposed Changes to 3GPP TS 29.503 ***** Table 6.1.6.2.6-1: Definition of type DnnInfo Attribute name Data type P Cardinali Description ty dnn Dnn M 1 Data Network Name with Network Identifier only., or Wildcard DNN (NOTE) defaultDnnIndicator DefaultDnnIndica O 0..1 Indicates whether this DNN is the default DNN: tor true: The DNN is the default DNN (NOTE); false: The DNN is not the default DNN; If this attribute is absent it means the DNN is not the default DNN. lboRoamingAllowed LboRoamingAllo O 0..1 Indicates whether local breakout for the DNN is wed allowed when roaming: true: Allowed; false: Not allowed; If this attribute is absent it means not allowed. iwkEpsInd IwkEpsInd O 0..1 Indicates whether interworking with EPS is subscribed: true: Subscribed; false: Not subscribed; If this attribute is absent it means not subscribed. dnnBarred boolean C 0..1 Indicates whether the DNN is barred. Absence and false indicates "not barred". This attribute is only used on the Nudr interface. The UDM shall handle barred DNNs received from the UDR as not subscribed. invokeNefInd boolean O 0..1 Indicates whether the NEF based infrequent small data transfer shall be used for the PDU Session associated with the S-NSSAI and DNN. true: Used; false: Not used; If this attribute is absent it means not used. smfList array(NfInstanceI O 1..N Indicate the associated SMF(s) if the static IP d) address / prefix is used. sameSmfInd boolean O 0..1 Indicates whether the same SMF for multiple PDU sessions to the same DNN and S-NSSAI is required. true: Required; false: Not required; If this attribute is absent it means not required. hrSboAllowed boolean O 0..1 Indicates whether Session Breakout for HR Session in VPLMN is allowed (see 3GPP TS 23.502 [3] and 3GPP TS 23.548

[0060] ). true: Allowed; false: Not allowed; If this attribute is absent it means not allowed. enhancedSmfSelectio EnhancedSmfSe O 0..1 This IE may be present if the UDM supports nCriteria lectionCriteria Enhanced SMF Selection Provisioning. ladnServiceArea array(Tai) O 1..N Indicates the LADN Service Area. NOTE: If the dnn attribute contains the value of the Wildcard DNN ("*"), the defaultDnnIndicator shall not be set to true.Applicant’s Ref. P108743WO01 18 6.1.6.2.X Type: EnhSmfSelectionCriteria Table 6.1.6.2.X-1: Definition of type EnhSmfSelectionCriteria Attribute name Data type P Cardinality Description targetNetworkId PlmnNidId O 0..1 When present, it contains the Id of the target network where the SMF shall be selected together with other applicable selection parameters. smfNfServiceInstanceId NfServiceInstance O 0..1 When present, it shall contain the NF Service Instance Id of the SMF which shall be selected for the PDU session. smfNfInstanceId NfInstanceId O 0..1 When present, it shall contain the NF Instance Id of the SMF which shall be selected for the PDU session. smfNfServiceSetId NfServiceSetId O 0..1 When present, it shall contain the ID of the NF Service Set to which the SMF (which shall be selected for the PDU session) pertain to. smfNfSetId boolean C 0..1 When present, it shall contain the ID of the NF Set to which the SMF (which shall be selected for the PDU session) pertain to. locality string O 0..1 When present, it shall contain a locality information where the selected SMF shall be located. spatialConditions SpatialValidityCond O 0..1 When present, it shall contain spatial conditions for above SMF selection criteria to be followed. timeConditions ValidTimePeriod O 0..1 When present, it shall contain time conditions for above SMF selection criteria to be followed. 6.1.8 Feature Negotiation The optional features in table 6.1.8-1 are defined for the Nudm_SDM API. They shall be negotiated using the extensibility mechanism defined in clause 6.6 of 3GPP TS 29.500 [4]. Table 6.1.8-1: Supported Features Feature number Feature Name Description 1 SharedData When receiving a Nudm_SDM_Get service operation request to retrieve a UE's individual subscription data, and the request does not contain a supported-features query parameter indicating support of this feature, the UDM shall not include Shared Data Ids in the response. Instead the UDM may – based on operator policy – take no further action (i.e. allow the UE to get services based on only the UE's individual subscription data), or send the shared data as individual data (this may result in notifications of individual subscription data change – if so subscribed – when shared data, which are sent as individual data, are modified, and / or when the UE's Shared Data IDs are modified). 2 ImmediateReport When a NF consumer detects the UDM support ImmediateReport feature, it can indicate an immediateReport flag when invoking Nudm_SDM_Subscribe service operation. If UDM supports ImmediateReport received Nudm_SDM_Subscribe service operation request, it shall return the resource representation(s) of the monitored resource(s) in the service operation response body. 3 PatchReport If some of the modifications included in the PATCH request are not successfully implemented, the UDM reports the result of PATCH request execution to the consumer. See clause 5.2.7.2 of 3GPP TS 29.500 [4]. 4 Nssaa If the NF consumer does not support this feature, the UDM shall not include information of S-NSSAI(s) subject to Network Slice-SpecificApplicant’s Ref. P108743WO01 19 and Authorization in Get response messages, immediate reports within Subscribe response messages, or data change notifications where the data change is limited to S-NSSAI(s) subject to Network Slice-Specific Authentication and Authorization. 5 CAGFeature If the NF consumer does not support this feature, the UDM shall not include CAG information list in the message body with "200 OK" response (clause 5.2.2.2.3). The UDM performs action as executes step 2c of clause 5.3.2.2.2 and 5.3.2.2.3 if UE is allowed to access 5GS via CAG cell(s) only. 6 SharedDataTreatment This feature is an extension to the SharedData feature, i.e. support of SharedDataTreatment requires support of SharedData. When receiving a Nudm_SDM_Get service operation request to retrieve a UE's individual subscription data, and the request does not contain a supported-features query parameter indicating support of this feature, the UDM shall not include SharedDataTreatments in the SharedData returned in the response. Instead the UDM may – based on operator policy – take no further action (i.e. allow the UE to get services based on default treatment (i.e. individual data take precedence), or send the shared data which have non-default treatment as individual data. 7 sorTransparentSupport This flag indicates NF Consumer (e.g. AMF) support of receiving SoR Transparent Container instead of individual IEs from NF Producer (e.g. UDM). If the NF consumer does not support this feature, the NF Producer shall not include sorTransparentContainer, as defined in clause 6.1.6.2.26. Corresponding flag is also used by UDM to register (in NRF) its support of receiving SoR Transparent Container instead of individual IEs from the NF Consumer (e.g. AMF). If the UDM does not support this feature, the NF Consumer shall not include sorTransparentContainer, as defined in clause 6.1.6.2.25. 8 Nsac If the NF consumer does not support this feature, the UDM shall not include network slice admission control related information for S- NSSAI(s) in the message body with "200 OK" response (See clause 5.2.2.2.3). 9 SharedSmSubsData If the NF consumer does not support this feature, the UDM shall not take the alternative to include extendedSmSubsData in SmSubsData (clause 6.1.6.2.79). 10 ENA Enhanced Network Automation. If the UDM supports this feature, the UDM shall apply the nfChangeFilter IE received in the sdmSubscription and send the notifications accordingly (See clause 6.1.6.2.16 and 6.1.6.2.70). 11 Nssrg The NF consumer (i.e. AMF) that supports this feature shall support handling of NSSRG information received along with the subscribed S- NSSAIs as defined in clause 5.15.12 of 3GPP TS 23.501 [2]. If the NF consumer does not support this feature, the UDM may select the subset of the compatible Subscribed S-NSSAIs without including any information of Network Slice Simultaneous Registration Group. 12 upuTransparentSupport This flag indicates NF Consumer (e.g. AMF) support of receiving UE Parameters Update Transparent Container instead of individual IEs from NF Producer (e.g. UDM). If the NF consumer does not support this feature, the NF Producer shall not include upuTransparentContainer, as defined in clause 6.1.6.2.33. Corresponding flag is also used by UDM to register (in NRF) its support of receiving UE Parameters Update Transparent Container instead of individual IEs from the NF Consumer (e.g. AMF). If the UDM does not support this feature, the NF Consumer shall not include upuTransparentContainer, as defined in clause 6.1.6.2.25. 13 LimitedSubscriptions An NF consumer supporting this feature shall use one subscription for the changes of subscription data sets per UE without additional filter criteria, or with a specific filter criteria (e.g. dnn and / or singleNssai).Applicant’s Ref. P108743WO01 20 An NF consumer supporting this feature shall use one subscription for the changes of shared data sets. 14 SNPN-ID Support of SNPN-ID This flag indicates whether the NF Consumer (e.g. AMF) or NF producer (UDM) support receiving an SNPN-ID as an extension of the "plmn-id" query parameter, when retrieving Access And Mobility Subscription Data (either by querying the "{supi}" resource or the "{supi} / am-data" resource). If the NF Consumer is aware (e.g. from previous interactions) that the UDM does not support this feature, the NF Consumer should not send queries on the Nudm_SDM API including SNPN-ID in the "plmn-id" query parameter. Also, if the NF Consumer sent such query to UDM, and the UDM does not indicate support of this feature in the response, the NF Consumer should consider the response as invalid, since the response from UDM would have not considered the presence of the NID component of the SNPN-ID in the "plmn-id" parameter. 15 UeConSmfDataSubFilter UE Context in Smf Data Subscription Filter If the UDM supports this feature, the UDM shall handle the ueConSmfDataSubFilter IE received in the sdmSubscription and sends the notifications only for changes indicated in the IE. 16 TempSliceSupport If the NF consumer does not support this feature, the UDM shall not include network slice validity related information in the message body with "200 OK" response (See clause 5.2.2.2.2, 5.2.2.2.3, etc.). 17 ExpectedBehaviourMap This indicates that the NF Consumer (e.g. AMF / SMF) supports receiving Expected Behaviour Parameters as a map of ExpectedUeBehaviourData. X EnhSmfSelection This indicates that the NF Service Producer, i.e., the UDM, or NF Service Consumer, i.e., the AMF, supports provisioning or receiving the enhanced SMF selection criteria respectively. A.2 Nudm_SDM API openapi: 3.0.0 info: version: '2.3.0-alpha.3' title: 'Nudm_SDM' description: | Nudm Subscriber Data Management Service. © 2023, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). All rights reserved. externalDocs: description: 3GPP TS 29.503 Unified Data Management Services, version 18.2.0 url: 'https: / / www.3gpp.org / ftp / Specs / archive / 29_series / 29.503 / ' ------skip for clarity------ DnnInfo:type: object required: - dnn properties: dnn: anyOf: - $ref: 'TS29571_CommonData.yaml# / components / schemas / Dnn'Applicant’s Ref. P108743WO01 21 - $ref: defaultDnnIndicator: $ref: '# / components / schemas / DnnIndicator' lboRoamingAllowed: $ref: '# / components / schemas / LboRoamingAllowed'iwkEpsInd: $ref: '# / components / schemas / IwkEpsInd' dnnBarred: type: boolean invokeNefInd:type: boolean smfList: type: array items: $ref: 'TS29571_CommonData.yaml# / components / schemas / NfInstanceId' minItems: 1 sameSmfInd: type: boolean hrSboAllowed: type: boolean default: false ladnServiceArea: type: array items: $ref: 'TS29571_CommonData.yaml# / components / schemas / Tai'minItems: 1 enhSmfSelectionCriteria: $ref: '# / components / schemas / EnhSmfSelectionCriteria' EnhSmfSelectionCriteria: description: a number of enhanced SMF selection criteria type: object properties: targetNetworkId: $ref: 'TS29571_CommonData.yaml# / components / schemas / PlmnIdNid' smfNfServiceInstanceId: $ref: 'TS29510_Nnrf_NFDiscovery.yaml# / components / schemas / NfServiceInstance' smfNfInstanceId: $ref: 'TS29571_CommonData.yaml# / components / schemas / NfInstanceId'smfNfServiceSetId: $ref: 'TS29571_CommonData.yaml# / components / schemas / NfServiceSetId' smfNfSetId: $ref: 'TS29571_CommonData.yaml# / components / schemas / NfSetId' locality: type: string spatialConditions: $ref: 'TS29571_CommonData.yaml# / components / schemas / SpatialValidityCond' timeConditions: $ref: '# / components / schemas / ValidTimePeriod' ------skip for clarity------***** End Proposed Changes to 3GPP TS 29.503 ***** Figure 6

[0047] Figure 6 is a schematic block diagram of a network node 600 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 600 may be, for example, a core network node that implements a NF (e.g., AMF, SMF (e.g., V-SMF or H-SMF), UDM, NRF, or the like) or a network node that implements all or part of the functionality of an NF (e.g., all or part of the functionality of the AMF, SMF (e.g., V- SMF or H-SMF), UDM, NRF, or the like, as described herein). As illustrated, the network node 600 includes a one orApplicant’s Ref. P108743WO01 22 more processors 604 (e.g., Central Processing Units , Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and / or the like), memory 606, and a network interface 608. The one or more processors 604 are also referred to herein as processing circuitry. The one or more processors 604 operate to provide one or more functions of the network node 600 as described herein (e.g., one or more functions of the AMF, SMF (e.g., V- SMF or H-SMF), UDM, NRF, or the like, as described herein). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 606 and executed by the one or more processors 604. Figure 7

[0048] Figure 7 is a schematic block diagram that illustrates a virtualized embodiment of the network node 600 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 600 in which at least a portion of the functionality of the network node 600 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 600 includes one or more processing nodes 700 coupled to or included as part of a network(s) 702. Each processing node 700 includes one or more processors 704 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 706, and a network interface 708. In this example, functions 710 of the network node 600 described herein (e.g., one or more functions of the AMF, SMF (e.g., V-SMF or H-SMF), UDM, NRF, or the like, as described herein) are implemented at the one or more processing nodes 700 or distributed across the two or more processing nodes 700 in any desired manner. In some particular embodiments, some or all of the functions 710 of the network node 600 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) 700.

[0049] 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 600 or a node (e.g., a processing node 700) implementing one or more of the functions 710 of the network node 600 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). Figure 8

[0050] Figure 8 is a schematic block diagram of the network node 600 according to some other embodiments of the present disclosure. The network node 600 includes one or more modules 800, each of which is implemented in software. The module(s) 800 provide the functionality of the network node 600 described herein. This discussion is equally applicable to the processing node 700 of Figure 7 where the modules 800 may be implemented at one of the processing nodes 700 or distributed across multiple processing nodes 700.Applicant’s Ref. P108743WO01 23 Figure 9

[0051] Figure 9 is a schematic block diagram of a wireless communication device 212 (e.g., a UE) according to some embodiments of the present disclosure. As illustrated, the wireless communication device 212 includes one or more processors 902 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 904, and one or more transceivers 906 each including one or more transmitters 908 and one or more receivers 910 coupled to one or more antennas 912. The transceiver(s) 906 includes radio-front end circuitry connected to the antenna(s) 912 that is configured to condition signals communicated between the antenna(s) 912 and the processor(s) 902, as will be appreciated by on of ordinary skill in the art. The processors 902 are also referred to herein as processing circuitry. The transceivers 906 are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device 212 (or UE) described above may be fully or partially implemented in software that is, e.g., stored in the memory 904 and executed by the processor(s) 902. Note that the wireless communication device 212 may include additional components not illustrated in Figure 9 such as, e.g., one or more user interface components (e.g., an input / output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and / or the like and / or any other components for allowing input of information into the wireless communication device 212 and / or allowing output of information from the wireless communication device 212), a power supply (e.g., a battery and associated power circuitry), etc.

[0052] 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 wireless communication device 212 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). Figure 10

[0053] Figure 10 is a schematic block diagram of the wireless communication device 212 according to some other embodiments of the present disclosure. The wireless communication device 212 includes one or more modules 1000, each of which is implemented in software. The module(s) 1000 provide the functionality of the wireless communication device 212 (or UE) described herein.

[0054] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program codeApplicant’s Ref. P108743WO01 24 stored in memory includes program instructions for one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0055] 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.).

[0056] Some of the embodiments that have been described above can be summarized in the following manner: Some embodiments 1. A method performed by first network node in a core network of a cellular communications system, the method comprising: • sending (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; • receiving (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria; and • performing (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE. 2. The method of embodiment 1, wherein the one or more SMF selection criteria comprise any one or more of the following: • information that indicates a target PLMN for SMF selection; • information that indicates an SMF NF instance for SMF selection; • information that indicates a SMF NF service set for SMF selection; • information that indicates an SMF NF set for SMF selection; or • information that indicates a locality for SMF selection. 3. The method of embodiment 1 or 2, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more spatial (i.e., geographical) conditions for applying the one or more SMF selection criteria.Applicant’s Ref. P108743WO01 25 4. The method of any of embodiments 1 to 3, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more time-based conditions for applying the one or more SMF selection criteria. 5. The method of any of embodiments 1 to 4, further comprising: determining (505) that the one or more conditions for applying the one or more SMF selection criteria are satisfied; wherein performing (505-508) SMF selection for the PDU session of the UE comprises performing (506-508) SMF selection for the PDU session based on the SMF selection criteria responsive to determining (505) that the one or more conditions for applying the one or more SMF selection criteria are satisfied. 6. The method of any of embodiments 1 to 5, wherein performing (506-508) SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE comprises: sending (506), to a third network node, a discovery request comprising at least one query parameter that correspond to at least one of the one or more SMF selection criteria; and receiving (508), from the third network node, a response to the discovery request, the response comprising information that identifies one or more candidate SMFs that satisfy the discovery request. 7. The method of embodiment 6, wherein the third network node is a Network Repository Function, NRF. 8. The method of embodiment 6 or 7, wherein performing (506-508) SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE further comprises selecting (510) a SMF from the one or more candidate SMFs. 9. The method of embodiment 8, wherein the selected SMF is in a Public Land Mobile Network, PLMN, other than a PLMN of the AMF. 10. The method of embodiment 9, further comprising: selecting (510) a Visited SMF, V-SMF, in the PLMN of the AMF; and sending (510) a create session management, SM, context request towards the selected V-SMF, the create SM context request comprising information that indicates the selected SMF in the PLMN other than the PLMN of the AMF as a Home SMF, H-SMF.Applicant’s Ref. P108743WO01 26 11. The method of any of embodiments 1 to 10, the first network node is an Access and Mobility Management Function, AMF. 12. The method of any of embodiments 1 to 11, wherein the second network node is a Unified Data Management, UDM, network function. 13. A first network node for a core network of a cellular communications system, the first network node adapted to: • send (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; • receive (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria; and • perform (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE. 14. The first network node of embodiment 13, further adapted to perform the method of any of embodiments 2 to 12. 15. A first network node for a core network of a cellular communications system, the first network node comprising: • a communication interface; and • processing circuitry associated with the communication interface, the processing circuitry configured to cause the first network node to: o send (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; o receive (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: ▪ one or more SMF selection criteria; and ▪ one or more conditions for applying the one or more SMF selection criteria; and o perform (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE. 16. The first network node of embodiment 15, wherein the processing circuitry is further configured to cause the first network node to perform the method of any of embodiments 2 to 12.Applicant’s Ref. P108743WO01 27 17. A method performed by second network node in a core network of a cellular communications system, the method comprising: • receiving (502), from a first network node, a request for Session Management Function, SMF, selection subscription data of a UE; • sending (504), to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria. 18. The method of embodiment 17, wherein the one or more SMF selection criteria comprise any one or more of the following: • information that indicates a target PLMN for SMF selection; • information that indicates an SMF NF instance for SMF selection; • information that indicates a SMF NF service set for SMF selection; • information that indicates an SMF NF set for SMF selection; or • information that indicates a locality for SMF selection. 19. The method of embodiment 17 or 18, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more spatial (i.e., geographical) conditions for applying the one or more SMF selection criteria. 20. The method of any of embodiments 17 to 19, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more time-based conditions for applying the one or more SMF selection criteria. 21. The method of any of embodiments 17 to 20, wherein the first network node is an Access and Mobility Management Function, AMF. 22. The method of any of embodiments 17 to 21, wherein the second network node is a Unified Data Management, UDM, network function. 23. A second network node for a core network of a cellular communications system, the second network node adapted to: • receive (502), from a first network node, a request for Session Management Function, SMF, selection subscription data of a UE;Applicant’s Ref. P108743WO01 28 • send (504), to the first network node, SMF subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria. 24. The second network node of embodiment 23, further adapted to perform the method of any of embodiments 18 to 22. 25. A second network node for a core network of a cellular communications system, the second network node comprising: • a communication interface; and • processing circuitry associated with the communication interface, the processing circuitry configured to cause the second network node to: o receive (502), from a first network node, a request for Session Management Function, SMF, selection subscription data of a UE; o send (504), to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: ▪ one or more SMF selection criteria; and ▪ one or more conditions for applying the one or more SMF selection criteria. 26. The second network node of embodiment 25, wherein the processing circuitry is further configured to cause the second network node to perform the method of any of embodiments 18 to 22.

Claims

Applicant’s Ref. P108743WO01 29 Claims What is claimed is:

1. A method performed by first network node in a core network of a cellular communications system, the method comprising: • sending (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; • receiving (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria; and • performing (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE.

2. The method of claim 1, wherein the one or more SMF selection criteria comprise any one or more of the following: • information that indicates a target PLMN for SMF selection; • information that indicates an SMF NF instance for SMF selection; • information that indicates a SMF NF service set for SMF selection; • information that indicates an SMF NF set for SMF selection; or • information that indicates a locality for SMF selection.

3. The method of claim 1 or 2, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more spatial (i.e., geographical) conditions for applying the one or more SMF selection criteria.

4. The method of any one of claim 1 to 3, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more time-based conditions for applying the one or more SMF selection criteria.

5. The method of any one of claim 1 to 4, further comprising: determining (505) that the one or more conditions for applying the one or more SMF selection criteria are satisfied; wherein performing (505-508) SMF selection for the PDU session of the UE comprises performing (506-508) SMF selection for the PDU session based on the SMF selection criteria responsive to determining (505) that the one or more conditions for applying the one or more SMF selection criteria are satisfied.Applicant’s Ref. P108743WO01 30 6. The method of any one of claim 1 to 5, wherein performing (506-508) SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE comprises: sending (506), to a third network node, a discovery request comprising at least one query parameter that correspond to at least one of the one or more SMF selection criteria; and receiving (508), from the third network node, a response to the discovery request, the response comprising information that identifies one or more candidate SMFs that satisfy the discovery request.

7. The method of claim 6, wherein the third network node is a Network Repository Function, NRF.

8. The method of claim 6 or 7, wherein performing (506-508) SMF selection for the PDU session of the UE based on the SMF selection subscription data of the UE further comprises selecting (510) a SMF from the one or more candidate SMFs.

9. The method of claim 8, wherein the selected SMF is in a Public Land Mobile Network, PLMN, other than a PLMN of the AMF.

10. The method of claim 9, further comprising: selecting (510) a Visited SMF, V-SMF, in the PLMN of the AMF; and sending (510) a create session management, SM, context request towards the selected V-SMF, the create SM context request comprising information that indicates the selected SMF in the PLMN other than the PLMN of the AMF as a Home SMF, H-SMF.

11. The method of any one of claim 1 to 10, wherein the first network node is an Access and Mobility Management Function, AMF.

12. The method of any one of claim 1 to 11, wherein the second network node is a Unified Data Management, UDM, network function.

13. A first network node for a core network of a cellular communications system, the first network node adapted to: • send (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; • receive (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising:Applicant’s Ref. P108743WO01 31 o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria; and • perform (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE.

14. The first network node of claim 13, further adapted to perform the method of any one of claim 2 to 12.

15. A first network node for a core network of a cellular communications system, the first network node comprising: • a communication interface; and • processing circuitry associated with the communication interface, the processing circuitry configured to cause the first network node to: o send (502), to a second network node, a request for Session Management Function, SMF, selection subscription data of a UE; o receive (504), from the second network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: ▪ one or more SMF selection criteria; and ▪ one or more conditions for applying the one or more SMF selection criteria; and o perform (506-508) SMF selection for a PDU session of the UE based on the SMF selection subscription data of the UE.

16. The first network node of claim 15, wherein the processing circuitry is further configured to cause the first network node to perform the method of any one of claim 2 to 12.

17. A method performed by second network node in a core network of a cellular communications system, the method comprising: • receiving (502), from a first network node, a request for Session Management Function, SMF, selection subscription data of a UE; • sending (504), to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria.

18. The method of claim 17, wherein the one or more SMF selection criteria comprise any one or more of the following:Applicant’s Ref. P108743WO01 32 • information that indicates a target PLMN for • information that indicates an SMF NF instance for SMF selection; • information that indicates a SMF NF service set for SMF selection; • information that indicates an SMF NF set for SMF selection; or • information that indicates a locality for SMF selection.

19. The method of claim 17 or 18, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more spatial (i.e., geographical) conditions for applying the one or more SMF selection criteria.

20. The method of any one of claim 17 to 19, wherein the one or more conditions for applying the one or more SMF selection criteria comprise one or more time-based conditions for applying the one or more SMF selection criteria.

21. The method of any one of claim 17 to 20, wherein the first network node is an Access and Mobility Management Function, AMF.

22. The method of any one of claim 17 to 21, wherein the second network node is a Unified Data Management, UDM, network function.

23. A second network node for a core network of a cellular communications system, the second network node adapted to: • receive (502), from a first network node, a request for Session Management Function, SMF, selection subscription data of a UE; • send (504), to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: o one or more SMF selection criteria; and o one or more conditions for applying the one or more SMF selection criteria.

24. The second network node of claim 23, further adapted to perform the method of any one claim 18 to 22.

25. A second network node for a core network of a cellular communications system, the second network node comprising: • a communication interface; and • processing circuitry associated with the communication interface, the processing circuitry configured to cause the second network node to:Applicant’s Ref. P108743WO01 33 o receive (502), from a first network a for Session Management Function, SMF, selection subscription data of a UE; o send (504), to the first network node, SMF selection subscription data of the UE in response to the request, the SMF selection subscription data of the UE comprising: ▪ one or more SMF selection criteria; and ▪ one or more conditions for applying the one or more SMF selection criteria.

26. The second network node of claim 25, wherein the processing circuitry is further configured to cause the second network node to perform the method of any one of claim 18 to 22.

Images