UE, communication device, method of UE, and method of communication device

Abstract

There are service requirements defined in 3GPP TS 22.261. However, there are no clear mechanisms defined in the 3GPP specifications as to how the requirements can be realized. [Solution] A method for a User Equipment (UE) includes transmitting first information indicating a first network slice available in a first network in which the UE is located and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network, and receiving third information indicating a second network in which the second network slice is available.

Description

Technical Field

[0001] The present disclosure relates to a method for a User Equipment (UE), a method for a communication device, a UE, and a communication device.

Background Art

[0002] There are the following service requirements defined in Non-Patent Document 2. - For a roaming UE that activates a service / application that requests a network slice that is not provided by the serving network but is available within the area from another network, the HPLMN shall be able to provide the UE with priority information of VPLMNs to which the UE can register for the network slice.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

[0004] However, regarding the method for realizing the requirements shown above, no clear mechanism is defined in the 3GPP specification. [Means for Solving the Problems]

[0005] In an aspect of the present disclosure, a method of a user equipment (UE) includes transmitting first information indicating a first network slice available in a first network where the UE is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The method includes receiving third information indicating a second network where the second network slice is available.

[0006] In an aspect of the present disclosure, a method of a communication device includes receiving first information indicating a first network slice available in a first network where a user equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The method includes transmitting third information indicating a second network where the second network slice is available.

[0007] In an aspect of the present disclosure, a method of a user equipment (UE) includes receiving first information indicating a first network where a first network slice is available. The method includes transmitting, after receiving the first information, second information indicating a second network slice available in a second network where the UE is located, and third information indicating the first network slice required by a service or application activated in the UE and not available in the second network.

[0008] In an aspect of the present disclosure, a method of a communication device includes transmitting first information indicating a first network where a first network slice is available. The method includes receiving, after transmitting the first information, second information indicating a second network slice available in a second network where a user equipment (UE) is located, and third information indicating the first network slice required by a service or application activated in the UE and not available in the second network.

[0009] In an aspect of the present disclosure, a method of a User Equipment (UE) includes receiving a request to transmit first information indicating a first network slice available in a first network in which the UE is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The method includes transmitting the first information and the second information after receiving the request.

[0010] In an aspect of the present disclosure, a method of a communication device includes transmitting a request to transmit first information indicating a first network slice available in a first network in which a User Equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The method includes receiving the first information and the second information after transmitting the request.

[0011] In an aspect of the present disclosure, a method of a User Equipment (UE) includes transmitting first information indicating a first network slice for which the UE requests registration in a first network. The method includes receiving second information indicating a second network slice. The second network slice is a network slice subscribed to by the UE, is different from the first network slice, and is available in a second network.

[0012] In an aspect of the present disclosure, a method of a communication device includes receiving first information indicating a first network slice for which a user equipment (UE) requests registration in a first network. The method includes transmitting second information indicating a second network slice. The second network slice is a network slice subscribed by the UE, is different from the first network slice, and is available in a second network.

[0013] In an aspect of the present disclosure, a user equipment (UE) includes means for transmitting first information indicating a first network slice available in a first network in which the UE is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The UE includes means for receiving third information indicating a second network in which the second network slice is available.

[0014] In an aspect of the present disclosure, a communication device includes means for receiving first information indicating a first network slice available in a first network in which a user equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. The communication device includes means for transmitting third information indicating a second network in which the second network slice is available.

[0015] In an aspect of the present disclosure, a User Equipment (UE) includes means for receiving first information indicating a first network in which a first network slice is available. The UE includes means for transmitting, after receiving the first information, second information indicating a second network slice available in a second network where the UE is located, and third information indicating the first network slice that is required by a service or application activated in the UE and is not available in the second network.

[0016] In an aspect of the present disclosure, a communication device includes transmitting first information indicating a first network in which a first network slice is available. The communication device includes receiving, after transmitting the first information, second information indicating a second network slice available in a second network where a User Equipment (UE) is located, and third information indicating the first network slice that is required by a service or application activated in the UE and is not available in the second network.

[0017] In an aspect of the present disclosure, a User Equipment (UE) includes means for receiving a request to transmit first information indicating a first network slice available in a first network where the UE is located, and second information indicating a second network slice that is required by a service or application activated in the UE and is not available in the first network. The UE includes means for transmitting the first information and the second information after receiving the request.

[0018] In an aspect of the present disclosure, a communication device includes means for transmitting a request for transmitting first information indicating a first network slice available in a first network where a user equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. After transmitting the request, the communication device includes means for receiving the first information and the second information.

[0019] In an aspect of the present disclosure, a user equipment (UE) includes means for transmitting first information indicating a first network slice for which the UE requests registration in a first network. The UE includes means for receiving second information indicating a second network slice. The second network slice is a network slice subscribed by the UE, is different from the first network slice, and is available in a second network.

[0020] In an aspect of the present disclosure, a communication device includes means for receiving first information indicating a first network slice for which a user equipment (UE) requests registration in a first network. The communication device includes means for transmitting second information indicating a second network slice. The second network slice is a network slice subscribed by the UE, is different from the first network slice, and is available in a second network.

Brief Description of the Drawings

[0021]

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DETAILED DESCRIPTION OF THE INVENTION

[0022] <Abbreviations> For the purposes of this specification, the abbreviations given in Non-Patent Document 1 and the following ones apply. The abbreviations defined in this specification shall take precedence over the definitions of the same abbreviations in Non-Patent Document 1 if there are such same abbreviations in Non-Patent Document 1.

[0023] 4G-GUTI 4G Globally Unique Temporary UE Identity 5GC 5G Core Network 5GLAN 5G Local Area Network 5GS 5G System 5G-AN 5G Access Network 5G-AN PDB 5G Access Network Packet Delay Budget 5G-EIR 5G-Equipment Identity Register 5G-GUTI 5G Globally Unique Temporary Identifier 5G-BRG 5G Broadband Residential Gateway 5G-CRG 5G Cable Residential Gateway 5G GM 5G Grand Master 5G-RG 5G Residential Gateway 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier 5G VN 5G Virtual Network 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AMF-G Geographically selected Access and Mobility Management Function AMF-NG Non-Geographically selected Access and Mobility Management Function AS Access Stratum ATSSS Access Traffic Steering, Switching, Splitting ATSSS-LL ATSSS Low-Layer AUSF Authentication Server Function AUTN Authentication token BCCH Broadcast Control Channel BMCA Best Master Clock Algorithm BSF Binding Support Function CAG Closed Access Group CAPIF Common API Framework for 3GPP northbound APIs CHF Charging Function CN PDB Core Network Packet Delay Budget CP Control Plane DAPS Dual Active Protocol Stacks DL Downlink DN Data Network DNAI DN Access Identifier DNN Data Network Name DRX Discontinuous Reception DS-TT Device-side TSN translator ePDG evolved Packet Data Gateway EBI EPS Bearer Identity EPS Evolved Packet System EUI Extended Unique Identifier FAR Forwarding Action Rule FN-BRG Fixed Network Broadband RG FN-CRG Fixed Network Cable RG FN-RG Fixed Network RG FQDN Fully Qualified Domain Name GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier GUTI Globally Unique Temporary UE Identity HPLMN Home Public Land Mobile Network HR Home Routed (roaming) IAB Integrated access and backhaul IMEI / TAC IMEI Type Allocation Code IPUPS Inter PLMN UP Security I-SMF Intermediate SMF I-UPF Intermediate UPF LADN Local Area Data Network LBO Local Break Out (roaming) LMF Location Management Function LoA Level of Automation LPP LTE Positioning Protocol LRF Location Retrieval Function MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MITM Man In the Middle MNC Mobile Network Code MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol N3IWF Non-3GPP InterWorking Function N3GPP Non-3GPP access N5CW Non-5G-Capable over WLAN NAI Network Access Identifier NAS Non-Access-Stratum NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NID Network identifier NPN Non-Public Network NR New Radio NRF Network Repository Function NSI ID Network Slice Instance Identifier NSSAA Network Slice-Specific Authentication and Authorization NSSAAF Network Slice-Specific Authentication and Authorization Function NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy NSSRG Network Slice Simultaneous Registration Group NW-TT Network-side TSN translator NWDAF Network Data Analytics Function PCF Policy Control Function PDB Packet Delay Budget PDR Packet Detection Rule PDU Protocol Data Unit PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public Land Mobile Network PNI-NPN Public Network Integrated Non-Public Network PPD Paging Policy Differentiation PPF Paging Proceed Flag PPI Paging Policy Indicator PSA PDU Session Anchor PTP Precision Time Protocol QFI QoS Flow Identifier QoE Quality of Experience RACS Radio Capabilities Signalling optimisation (R)AN (Radio) Access Network RAT Radio Access Technology RG Residential Gateway RIM Remote Interference Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RSN Redundancy Sequence Number SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SMF Session Management Function SMSF Short Message Service Function SN Sequence Number SN name Serving Network Name. SNPN Stand-alone Non-Public Network S-NSSAI Single Network Slice Selection Assistance Information SSC Session and Service Continuity SSCMSP Session and Service Continuity Mode Selection Policy SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier SV Software Version TMSI Temporary Mobile Subscriber Identity TNAN Trusted Non-3GPP Access Network TNAP Trusted Non-3GPP Access Point TNGF Trusted Non-3GPP Gateway Function TNL Transport Network Layer TNLA Transport Network Layer Association TSC Time Sensitive Communication TSCAI TSC Assistance Information TSN Time Sensitive Networking TSN GM TSN Grand Master TSP Traffic Steering Policy TT TSN Translator TWIF Trusted WLAN Interworking Function UCMF UE radio Capability Management Function UDM Unified Data Management UDR Unified Data Repository UDSF Unstructured Data Storage Function UE User Equipment UL Uplink UL CL Uplink Classifier UPF User Plane Function URLLC Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy VID VLAN Identifier VLAN Virtual Local Area Network VPLMN Visited Public Land Mobile Network W-5GAN Wireline 5G Access Network W-5GBAN Wireline BBF Access Network W-5GCAN Wireline 5G Cable Access Network W-AGF Wireline Access Gateway Function

[0024] <Definition> For the purposes of this specification, the terms and definitions given in Non-Patent Document 1, as well as the following, apply. Terms defined in this specification shall take precedence over the definitions of the same terms in Non-Patent Document 1, if any.

[0025] <General Introduction> Those skilled in the art will understand that the elements in the figures are shown in a simplified manner and need not necessarily be drawn to scale. Further, with respect to the structure of a device, one or more components of the device may be represented by conventional symbols in the figures, and the figures may show only such specific details as are appropriate to understand the aspects of the present disclosure without obscuring the figures with details that will be readily apparent to those skilled in the art who benefit from the description herein.

[0026] To facilitate understanding of the principles of the present disclosure, reference is now made to the aspects shown in the figures and specific terms are used to describe those principles. Nevertheless, it will be understood that it is not intended thereby to limit the scope of the present disclosure. Such modifications and further corrections to the systems shown, as well as such further applications of the principles of the present disclosure as would normally occur to those skilled in the art, should be construed as being within the scope of the present disclosure.

[0027] The terms "comprising", "comprises", or any other variation thereof are intended to cover non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may also include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices, entities, subsystems, elements, structures, or components that begin with "comprising" do not, without further limitation, exclude the presence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures, or additional components. Throughout this specification, phrases such as "in one aspect", "in another aspect", and similar terms, when they appear, may all refer to the same aspect but do not necessarily have to.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The systems, methods, and examples provided herein are illustrative only and not intended to be limiting.

[0029] In the following specification and claims, reference is made to a number of terms that are defined to have the following meanings. The singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise.

[0030] When data is meaningful information and represents a value that results from a parameter, the information used herein is associated with data and findings. Further, findings mean an understanding of an abstract or concrete concept. It should be noted that this exemplary system is simplified to facilitate the description of the subject matter of this disclosure and is not intended to limit the scope of this disclosure. In addition to or instead of the system, other devices, systems, and configurations may be used to implement the aspects disclosed herein, and all such aspects are assumed to be within the scope of this disclosure.

[0031] Each of the aspects, and the elements included in each of the aspects described below, can be implemented independently or in combination with each other. The aspects include novel features that are different from each other. Therefore, the aspects contribute to the achievement of the objective or the solution of different problems from each other, and contribute to obtaining different advantages from each other.

[0032] It is assumed that the User Equipment (UE) recognizes all network slices available in the cell in the VPLMN when the UE is in the CM-IDLE state, the CM-CONNECTED state, or the CM-CONNECTED state of RRC inactive.

[0033] For example, FIGS. 1 and 2 show the information provided to the UE by the AMF and the cell, respectively. The UE can understand all the network slices available within the cell based on two pieces of information, one being the information from the AMF and the other being the information from the cell. For example, the UE receives a NAS message from the AMF. For example, the NAS message includes information indicating that the first group identified by group ID1 includes network slice A and network slice B, the second group identified by group ID2 includes network slice C and network slice D, and the third group identified by group ID3 includes network slice E and network slice F. In addition, the UE receives system information from the (R)AN node that controls the cell. "Cell" can mean the "(R)AN node that controls the cell". For example, the (R)AN node can mean an NG-RAN node or a gNB. The system information includes Slice Info. The UE can receive an RRC release message from the (R)AN node. The Slice Info can be included in the RRC release message. For example, the Slice Info can be represented as slice information. For example, the Slice Info includes group ID1, group ID2, and group ID3. The Slice Info can indicate the group IDs available in the cell. In the example of FIGS. 1 and 2, the UE can understand that network slice A, network slice B, network slice C, network slice D, network slice E, and network slice F are available within the cell based on the information included in the NAS message and the Slice Info included in the system information or the RRC release message.

[0034] In addition, the group ID in the slice info is associated with the frequency information. In the example of FIG. 2, the group ID 1 (or network slices A and B in the first group identified by the group ID 1) is associated with 800 MHz, 900 MHz, and 1.5 GHz in order of priority. For example, 800 MHz has the highest priority in the group ID 1. For example, 1.5 GHz has the lowest priority in the group ID 1. For example, 900 MHz has a medium priority between 800 MHz and 1.5 GHz in the group ID 1.

[0035] FIG. 1 shows an example of information available to a User Equipment (UE) for at least one of cell selection and cell reselection based on network slice priority.

[0036] FIG. 2 illustrates an example of slice info broadcast by a cell to a UE.

[0037] According to the present disclosure, the HPLMN operator can enable the UE to select a VPLMN based on the availability of network slices in each VPLMN where the UE roams. The prioritization information can be represented as Slice Availability information. "The S-NSSAI is available" may mean that the network slice identified by the S-NSSAI is available.

[0038] <The first aspect> To enable the Home Public Land Mobile Network (HPLMN) operator to provide the UE with prioritization information regarding the Visited Public Land Mobile Network (VPLMN) while the UE is roaming, the HPLMN operator requires a mechanism in Non-Patent Document 3, Non-Patent Document 4, and other 3GPP specifications for the UDM to provide the UE with prioritization information regarding the VPLMN based on the location where the UE moves.

[0039] In addition, 3GPP operators are generally known to configure the network slices available in a cell based on the Frequency Band (FB) used by the cell. If a network slice requires an extremely high bandwidth, the network slice can only be provided by a cell with a high FB. On the other hand, if a network slice needs to support a UE with high-speed and random movement, since a low FB provides wide and flexible radio wave penetration, the UE uses a cell with a low FB. Considering this matter, it is beneficial for the UE when the HPLMN provides prioritization information of the VPLMN including network slice information available along with FB information. Then, the UE can select a new VPLMN with the best FB that the UE desires to access the network slice the UE is interested in.

[0040] This first aspect discloses a mechanism that enables the HPLMN operator to provide the UE with prioritization information regarding the VPLMN while the UE is roaming. Within the prioritization information provided regarding the VPLMN, each VPLMN may have associated information including the network slices available for each location and each FB.

[0041] The first aspect can solve the problem that there is no clear mechanism defined in the 3GPP specification regarding a method capable of realizing the requirements in Non-Patent Document 2.

[0042] <First Example of the First Aspect> The first example of the first aspect discloses a method in which the UDM 75 provides the UE 3 with network slice-related information and priority ranking information regarding the VPLMN during the registration procedure.

[0043] In addition, the first example of the first aspect discloses a mechanism in which the UE 3 provides the UDM 75 with VPLMN-related information during the registration procedure.

[0044] To make the first example of the first aspect understandable, the first example of the first aspect gives the following examples.

[0045] Regarding the UE 3: - The UE 3 has installed four applications, namely, APL1, APL2, APL3, and APL4, and these applications are respectively associated with the network slices S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 based on the URSP rules in the UE 3.

[0046] - When the UE starts the registration procedure for VPLMN1, the UE 3 has three active applications, APL1, APL2, and APL3. That is, the UE 3 is interested in the network slices S-NSSAI1, S-NSSAI2, and S-NSSAI3 that are permitted access by VPLMN1. The application can be represented as a service. The application can correspond to a service. For example, the UE 3 can activate APL1, require Service 1 corresponding to APL1, and perform the registration procedure corresponding to S-NSSAI1.

[0047] Regarding VPLMN1: - Cell 501 supports network slices S-NSSAI1 and S-NSSAI2. For example, Cell 501 is controlled by a (R)AN node in VPLMN1. For example, the (R)AN node may mean an NG-RAN node or a gNB.

[0048] Regarding the HPLMN of UE3: - UDM 75 has subscriber data regarding UE3 that includes S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 in the subscribed NSSAI for UE3. For example, UDM 75 is included in the HPLMN.

[0049] The detailed process of the first example of the first aspect is as described below.

[0050] Step 0. UDM 75 in the HPLMN maintains a database (DB) based on an operator roaming agreement among roaming partners worldwide. The DB may include a list of roaming partners for each location. The list of roaming partners may be represented as a list of VPLMNs. For example, the HPLMN has roaming partners VPLMN1, VPLMN2, and VPLMN3 in Tokyo, Japan in order of priority. For example, the list of roaming partners (or the list of VPLMNs) includes VPLMN1, VPLMN2, and VPLMN3 in Tokyo, Japan in order of priority.

[0051] For each VPLMN entry in the list, the UDM 75 may hold, together with the FB, the S-NSSAI available at that location. For example, in VPLMN1 in Tokyo, S-NSSAI1 and S-NSSAI2 are available in the 900 MHz frequency band. For example, the UDM 75 holds information indicating that S-NSSAI1 and S-NSSAI2 are available in the 900 MHz frequency band in VPLMN1 in Tokyo. For example, for each VPLMN entry in the list, the UDM 75 may hold the S-NSSAI available at that location. For example, for each VPLMN entry in the list, the UDM 75 may hold, for each RAN type, the S-NSSAI available at that location. For example, the RAN type may be a RAT type.

[0052] This DB is basically managed by the Operation and Maintenance (O&M) process. In addition to the O&M process, the HPLMN operator uses dynamic DB updates based on an update mechanism as disclosed by this disclosure.

[0053] In addition, the UDM 75 has subscriber data regarding UE3 that includes S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 in the subscribed NSSAI for UE3.

[0054] Step 1. UE3 activates some applications in UE3 as an inbound roamer for VPLMN1. Based on the URSP rules in UE3, UE3 recognizes the S-NSSAI that UE3 needs to request from VPLMN1 in the registration procedure. For example, four applications APL1, APL2, APL3, and APL4 are installed in UE3. Among the four applications, three applications APL1, APL2, and APL3 are activated, and S-NSSAI1, S-NSSAI2, and S-NSSAI3 are the network slices associated with each application respectively based on the URSP rules in UE3.

[0055] Step 2-1. The UE 3 may receive system information from the cell 501 indicating a list of S-NSSAIs supported by the cell 501. The cell 501 may be represented as an (R)AN node, an NG-RAN node, or a gNB that controls the cell 501. For example, the cell 501 supports S-NSSAI1 and S-NSSAI2. For example, if the cell 501 supports S-NSSAI1 and S-NSSAI2, the system information indicates a list including S-NSSAI1 and S-NSSAI2. For example, the system information includes slice info including S-NSSAI1 and S-NSSAI2.

[0056] Step 2-2. UE3 may receive information of a list of S-NSSAIs supported by cell 501 in an RRC message. The RRC message may be an RRC release message or another existing RRC message. For example, cell 501 supports S-NSSAI1 and S-NSSAI2. For example, if cell 501 supports S-NSSAI1 and S-NSSAI2, the RRC message includes a list including S-NSSAI1 and S-NSSAI2. For example, the RRC message includes slice info including S-NSSAI1 and S-NSSAI2. For example, UE3 may receive at least one of system information in step 2-1 and an RRC message in step 2-2.

[0057] Step 3. UE3 sends a Registration Request message containing user identity, Requested NSSAI, Provided NSSAI, Interested NSSAI, Location, Tuned FB, UE Radio Capability, and Slice Availability feature support parameters to AMF7001. The Registration Request message may include an Available PLMNs list. AMF7001 is located in VPLMN1. The following bullets explain the details of each parameter.

[0058] - The user identity can be 5G-GUTI, SUCI, or SUPI. For example, the user identity can be 5G-GUTI, SUCI, or SUPI for UE3.

[0059] - The Requested NSSAI contains a list of S-NSSAIs that UE3 desires to request from VPLMN1. In this example, when UE3 recognizes based on Step 2-1 or Step 2-2 that S-NSSAI1 and S-NSSAI2 are network slices available in cell 501, UE3 adds S-NSSAI1 and S-NSSAI2 to the Requested NSSAI. That is, since the associated APL3 is active in UE3, UE3 also desires to request S-NSSAI3, but when there is no support for S-NSSAI3 by cell 501 and thus no chance of being accepted by AMF7001, UE3 does not request S-NSSAI3. In this example, the Requested NSSAI includes S-NSSAI1 and S-NSSAI2.

[0060] - The provided NSSAI may include a list of S-NSSAIs that are available in the cell of VPLMN1 where UE3 camps on. In this example, UE3 may add S-NSSAI1 and S-NSSAI2 based on the information received in steps 2-1 and 2-2. In this example, the provided NSSAI includes S-NSSAI1 and S-NSSAI2.

[0061] In one example, each S-NSSAI in the provided NSSAI may have associated information such as a list of FBs where the S-NSSAI is available or deployed in VPLMN1. UE3 may obtain the provided NSSAI in each FB by listening to the system information in each FB provided by VPLMN1. The provided NSSAI may be represented as available S-NSSAI(s). For example, UE3 may associate the FB where the system information is broadcast with the provided NSSAI.

[0062] In another example, each S-NSSAI in the provided NSSAI may have associated information such as a list of FBs, together with a RAT type.

[0063] In another example, each S-NSSAI in the provided NSSAI may have associated information such as a list of FBs, together with the VPLMN ID where the S-NSSAI is available in another VPLMN. UE3 may obtain the S-NSSAIs available in the FB in each VPLMN by listening to the system information in each FB in each VPLMN.

[0064] Note that each S-NSSAI in the provided NSSAI may have associated information such as a combination of FB, RAT type, and PLMN ID. For example, each S-NSSAI in the provided NSSAI is associated with at least one of FB, RAT type, and PLMN ID. The PLMN ID may mean the VPLMN ID.

[0065] - The NSSAI of interest may include a list of S-NSSAIs that UE3 is interested in. In this example, since APL1, APL2, and APL3 are active in UE3, UE3 may add S-NSSAI1, S-NSSAI2, and S-NSSAI3. For example, the NSSAI of interest may include S-NSSAI1, S-NSSAI2, and S-NSSAI3. In one example, the NSSAI of interest includes the S-NSSAIs that UE3 wants to register for VPLMN1, but the S-NSSAIs are not provided by the cell on which UE3 camps. For example, the NSSAI of interest may include S-NSSAI3.

[0066] - The location may be the location of UE3. The location may be the geographical location of UE3. For example, the location may be a Tracking Area Identity (TAI), an NR Cell Global Identity (NCGI) as defined in Non-Patent Document 5, an NR Cell Identity (NCI) as defined in Non-Patent Document 5, an E-UTRAN Cell Global Identifier (ECGI) as defined in Non-Patent Document 5, a Global Cable Identifier (GCI) as defined in Non-Patent Document 5, a common city name, a zip code, something formed by a GPS position, or a location represented in a city and geospatial location format as defined in Non-Patent Document 7.

[0067] - The FB to be tuned is the frequency band on which the UE is currently tuned. For example, the FB to be tuned is 800 MHz, 900 MHz, or 6 GHz.

[0068] In one example, the FB to be tuned may have associated information such as the RAT type.

[0069] - The UE radio function indicates the frequency bands supported by UE3. The UE radio function may also indicate a combination of the frequency bands and RAT types supported by UE3.

[0070] - The slice availability feature support parameter indicates that UE3 supports the network slice availability feature. That is, when UE3 receives slice availability information from UDM75 via AMF7001, UE3 can process the slice availability information and select a VPLMN based on the result of processing the received slice availability information. For example, the network slice availability feature indicates that UE3 can process the slice availability information and select a VPLMN based on the result of processing the received slice availability information. The processing of the slice availability information and the selection of the VPLMN based on the result of processing the received slice availability information are described below.

[0071] The slice availability feature support parameter may be represented as Slice Availability feature support.

[0072] - List of available PLMNs: UE3 may also include a list of available PLMNs at that location, along with the network slices supported by each PLMN in the list of available PLMNs and the frequency bands of each PLMN. UE3 obtains the list of available PLMNs by scanning radio frequencies in the 5GMM-IDLE mode or 5GMM-CONNECTED mode at that location to confirm the available PLMNs.

[0073] Step 4. AMF 7001 sends a Nudm_UECM_Registration message containing the VPLMN ID, the requested NSSAI, the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio capabilities, and the slice availability function support parameters to UDM 75. If AMF 7001 receives the slice availability function support parameters in the registration request message in Step 3, AMF 7001 may include the requested NSSAI, the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio capabilities, and the slice availability function support parameters. The Nudm_UECM_Registration message may include a list of available PLMNs. The following bullet points explain each parameter in detail.

[0074] - The VPLMN ID indicates the VPLMN in which UE 3 is registered. For example, the VPLMN ID may be the identification information of VPLMN1 in which UE 3 is registered. For example, the VPLMN ID indicates VPLMN1 in which UE 3 is registered.

[0075] - The location may be the same as the location in Step 3. AMF 7001 may generate the location parameter based on the information from cell 501. In this case, the location may be the NCGI, NCI, TAI, N3IWF user location information as defined in Non-Patent Document 6, TNGF user location information, TWIF user location information, W-AGF user location information.

[0076] - The requested NSSAI, the provided NSSAI, the NSSAI of interest, the tuned FB, the UE radio capabilities, the list of available PLMNs, and the slice availability function support parameters may be the same as those in Step 3.

[0077] For example, when AMF7001 receives a registration request message or any existing message between the AMF and the UE, or a new message between the AMF and the UE, from UE3, AMF7001 may send an Nudm_UECM_Registration message.

[0078] Step 5. Based on the information received in Step 4, UDM75 updates the database related to the network slice information supported in the VPLMN. For example, when UDM75 receives a provided NSSAI including a VPLMN ID1 identifying VPLMN1, a location set in Tokyo, and S-NSSAI1 and S-NSSAI2, UDM75 adds or updates the entry related to VPLMN1 in the roaming partner list (or the VPLMN list). In this case, for example, UDM75 adds an entry to the list indicating that S-NSSAI1 and S-NSSAI2 are available in VPLMN1 in Tokyo. For example, when UDM75 already stores an entry related to VPLMN1, UDM75 updates the entry based on the received information indicating that S-NSSAI1 and S-NSSAI2 are available in VPLMN1 in Tokyo. In addition, for example, when adding or updating an entry, UDM75 associates the frequency band indicated by the tuned FB with the entry. For example, when the tuned FB indicates 800 MHz, UDM adds an entry to the list indicating that S-NSSAI1 and S-NSSAI2 are available in VPLMN1 in Tokyo with respect to 800 MHz.

[0079] If the slice availability function support parameter is included in the Nudm_UECM_Registration message at step 4, the UDM75 sends an Nudm_UECM_Registration response message containing slice availability information to the AMF7001. The UDM75 generates slice availability information based on the parameters received in the Nudm_UECM_Registration message at step 4. The slice availability information indicates the S-NSSAIs available to the UE3 at the location where the UE3 is located. For example, the slice availability information can take one of the following forms.

[0080] - A priority list of VPLMNs with supported S-NSSAIs. The priority list of VPLMNs can be generated by the UDM75 based on the VPLMN ID, location, provided NSSAI, and NSSAI of interest received at step 4. For example, based on the VPLMN ID, location, provided NSSAI, and NSSAI of interest received at step 4, the UDM75 recognizes that the UE3 is interested in S-NSSAI1, S-NSSAI2, and S-NSSAI3, but the VPLMN1 identified by the VPLMN ID may only permit S-NSSAI1 and S-NSSAI2 for the UE3. In this situation, the UDM75 may select a VPLMN that supports all of S-NSSAI1, S-NSSAI2, and S-NSSAI3 and generate a priority list based on the roaming agreement with the VPLMN. For example, the priority list of VPLMNs includes a VPLMN that supports all of S-NSSAI1, S-NSSAI2, and S-NSSAI3 at the location. For example, the priority list of VPLMNs may indicate VPLMN2 that supports all of S-NSSAI1, S-NSSAI2, and S-NSSAI3 at the location.

[0081] - A priority list of VPLMNs with supported S-NSSAIs along with FB information. In addition to the above bullet, the UDM 75 also considers the provided NSSAI along with the FB and UE capabilities. For example, the priority list of VPLMNs includes VPLMNs that support all of S-NSSAI1, S-NSSAI2, and S-NSSAI3 with respect to the tuned FB and location received in step 4. Since this example provides the VPLMN with FB information, the UE 3 may tune to a cell with the indicated FB in the indicated VPLMN. For example, the priority list of VPLMNs may indicate VPLMN2 that supports all of S-NSSAI1, S-NSSAI2, and S-NSSAI3 with respect to the location and the tuned FB.

[0082] - A priority list of VPLMNs with supported S-NSSAIs, along with FB information regarding the location of the entire VPLMN coverage. In this example, UDM 75 does not consider the location information in step 4. Instead, UDM 75 generates a complete set of priority lists of VPLMNs with supported S-NSSAIs, along with FB information for each location covered by the VPLMN. The advantage of this example is that since a complete set of priority lists of VPLMNs is provided to UE 3, UE 3 does not need to obtain slice availability information as long as UE 3 stays in the same VPLMN. The value of the location can be the same as the location in step 3. For example, the priority list of VPLMNs can indicate the S-NSSAIs available in VPLMN2 for each location and FB. For example, the priority list of VPLMNs can indicate that the first S-NSSAI is available in the first VPLMN for the first location and 800 MHz, the second S-NSSAI is available in the first VPLMN for the first location and 900 MHz, the third S-NSSAI is available in the first VPLMN for the second location and 800 MHz, the fourth S-NSSAI is available in the first VPLMN for the second location and 900 MHz, the fifth S-NSSAI is available in the second VPLMN for the first location and 800 MHz, the sixth S-NSSAI is available in the second VPLMN for the first location and 900 MHz, the seventh S-NSSAI is available in the second VPLMN for the second location and 800 MHz, and the eighth S-NSSAI is available in the second VPLMN for the second location and 900 MHz.

[0083] - A priority list of VPLMNs with supported S-NSSAI based on the subscribed NSSAI. In this example, the UDM 75 considers the requested NSSAI at step 4 and the subscribed NSSAI in the UDM 75. When the UDM 75 refers to both the requested NSSAI and the subscribed NSSAI, the UDM 75 can understand the missing S-NSSAI(s) for which the UE 3 has not yet been granted access. In this example, the UDM 75 provides a priority list of VPLMNs including the VPLMNs with the missing S-NSSAI. In this example, the requested NSSAI has S-NSSAI1 and S-NSSAI2, while the UDM 75 holds S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 as the subscribed NSSAI for the UE 3. In this case, the UDM 75 understands that S-NSSAI3 and S-NSSAI4 are the missing S-NSSAI. Therefore, the UDM 75 provides a priority list of VPLMNs for S-NSSAI3 and S-NSSAI4. For example, the priority list of VPLMNs includes the VPLMNs that support S-NSSAI3 and S-NSSAI4.

[0084] The UDM 75 may generate the above priority list of VPLMNs that enumerates the VPLMNs in order of priority.

[0085] For example, when the UDM 75 receives from the AMF 7001 the Nudm_UECM_Registration message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF, the UDM 75 may send a Nudm_UECM_Registration response message.

[0086] For example, when the UDM 75 updates the database related to the supported network slice information in the VPLMN, the UDM 75 may send a Nudm_UECM_Registration response message.

[0087] Step 6. AMF 7001 sends a Registration Accept message containing the slice availability information received from the UDM 75 in the Nudm_UECM_Registration response message at step 5 to the UE 3. If the AMF 7001 does not receive the slice availability function support parameters from the UE 3 in the registration request message at step 3, the AMF 7001 does not include the slice availability information in the registration accept message. The registration accept message may include at least one of an Allowed NSSAI and a Rejected NSSAI.

[0088] For example, if the AMF 7001 receives a Nudm_UECM_Registration response message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from the UDM 75, the AMF 7001 may send a registration accept message.

[0089] Step 7. Upon receiving the registration accept message from the AMF 7001, the UE 3 sends a registration complete message containing the Rejected NSSAI, the location, and the tuned FB to the AMF 7001. The following bullet points explain the details of each parameter.

[0090] - The Rejected NSSAI is a list of S-NSSAIs requested by the UE 3 but rejected by the AMF 7001. For example, the Rejected NSSAI may be a list of S-NSSAIs included in the requested NSSAI but rejected by the AMF 7001. For example, the Rejected NSSAI may be the same as the Rejected NSSAI included in the registration accept message.

[0091] - The location and the tuned FB may be the same as those in step 3.

[0092] Note that each S-NSSAI in the rejected NSSAI may have associated information such as a combination of FB, RAT type, and PLMN ID. For example, each S-NSSAI in the rejected NSSAI is associated with at least one of FB, RAT type, and PLMN ID. For example, the PLMN ID can be a VPLMN ID.

[0093] Step 8. When receiving a registration completion message from UE3, AMF7001 sends a Nudm_UECM_Update message including the rejected NSSAI, the location, and the tuned FB to UDM75. The rejected NSSAI, location, and tuned FB included in the Nudm_UECM_Update message can be the same as those received in Step 7. The Nudm_UECM_Update message may include a VPLMN ID indicating the VPLMN in which UE3 is registered. For example, the VPLMN ID can be the identification information of VPLMN1 in which UE3 is registered. For example, the VPLMN ID indicates VPLMN1 in which UE3 is registered.

[0094] Step 9. Based on the information received in Steps 4 and 8, UDM75 updates the database related to the supported network slice information in the VPLMN. UDM75 stores information having the corresponding VPLMN ID, RAT, or FB supported by UE3, for example, the rejected NSSAI. In one example, when UDM75 determines based on the database in UDM75 or based on the available PLMN list that the S-NSSAI in the rejected NSSAI is provided by another VPLMN2, UDM75 may then send a Nudm_UECM_Update response message including slice availability information including VPLMN2 together with the S-NSSAI as the highest priority VPLMN to AMF7001.

[0095] Step 10. UDM 75 sends a Nudm_UECM_Update response message to AMF 7001. When AMF 7001 receives slice availability information in the Nudm_UECM_Update response message, AMF 7001 may send a new or existing NAS message to UE 3 to send the slice availability information.

[0096] For example, if UDM 75 receives a Nudm_UECM_Update message or any existing message between UDM and AMF, or a new message between UDM and AMF from AMF 7001, UDM 75 may send a Nudm_UECM_Update response message.

[0097] For example, if UDM 75 updates the database related to the supported network slice information in the VPLMN based on the information received in Steps 4 and 8, UDM 75 may send a Nudm_UECM_Update response message.

[0098] Step 11. UE3 examines the slice availability information received in the registration approval message in Step 6 and makes a decision on whether UE3 should move to the new VPLMN. For example, if the received slice availability information indicates that VPLMN2 supports S-NSSAI1, S-NSSAI2, and S-NSSAI3 at FB900 MHz, since all the active applications APL1, APL2, and APL3 in UE3 can be connected to the associated Data Network (DN), UE3 moves to cell 502 with FB900 MHz in VPLMN2. In one example, if UE3 finds in the slice availability information that another VPLMN2 can provide services for the S-NSSAI in the rejected NSSAI, UE3 may select VPLMN2 and initiate the registration procedure to register for the S-NSSAI rejected in VPLMN2. For example, if the received slice availability information indicates that VPLMN2 supports S-NSSAI1, S-NSSAI2, and S-NSSAI3 at FB900 MHz and that VPLMN2 has the highest priority among the VPLMNs in the received slice availability information, UE3 moves to cell 502 with FB900 MHz in VPLMN2.

[0099] Step 12. If UE3 decides to move to VPLMN2, UE3 can listen to cell 502 and receive system information to confirm that S-NSSAI1, S-NSSAI2, and S-NSSAI3 are supported.

[0100] Step 13. UE3 transmits a registration request message including user identification information, the requested NSSAI, the provided NSSAI, the NSSAI of interest, location, the tuned FB, UE radio capabilities, and slice availability function support parameters to AMF7002. AMF7002 is located in VPLMN2. For example, the requested NSSAI in step 13 includes S-NSSAI1, S-NSSAI2, and S-NSSAI3. For example, the provided NSSAI in step 13 includes S-NSSAI1, S-NSSAI2, and S-NSSAI3. For example, the NSSAI of interest in step 13 includes S-NSSAI1, S-NSSAI2, and S-NSSAI3.

[0101] Step 14. The registration procedure continues with step 4 in section 4.2.2.2.2 of non-patent document 4 for AMF7002. In this example, UE3 is permitted access to S-NSSAI1, S-NSSAI2, and S-NSSAI3 with respect to VPLMN2. For example, slice availability information received indicates that VPLMN2 and VPLMN3 support S-NSSAI1, S-NSSAI2, and S-NSSAI3 at FB 900 MHz, and among the VPLMNs in the received slice availability information, VPLMN2 has the highest priority and VPLMN3 has the second highest priority. If the registration with AMF7002 in VPLMN2 is rejected, UE3 may move to a cell having FB 900 MHz in VPLMN3.

[0102] The provided NSSAI may be represented as a first network slice available in the first network where UE3 is located. The NSSAI of interest may be represented as a second network slice required by the services or applications activated in UE3 and not available in the first network where UE3 is located. The slice availability information may be represented as information indicating the second network where the second network slice is available.

[0103] <Modification 1 of the first example of the first aspect> When the AMF 7001 sends a registration approval message to the UE 3 in step 6, the AMF 7001 may send a Nudm_UECM_Update message including a rejected NSSAI, a location, and a tuned FB to the UDM 75 as shown in step 8 without waiting for a registration completion message from the UE 3 in step 7.

[0104] <Modification 2 of the first example of the first aspect> Instead of the Nudm_UECM_Registration message in step 4, the AMF 7001 sends the required NSSAI, the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters to the UDM 75 by using a Nudm_SDM_Get message or any existing message between the AMF and the UDM, or a new message between the AMF and the UDM.

[0105] <Modification 3 of the first example of the first aspect> Instead of the Nudm_UECM_Registration response message in step 5, the UDM 75 sends slice availability information parameters to the AMF 7001 by using a Nudm_SDM_Get response message or any existing message between the AMF and the UDM, or a new message between the AMF and the UDM.

[0106] <Modification 4 of the first example of the first aspect> In step 11, UE3 stores the received slice availability information in the registration approval message from AMF7001 for later use. When an application in UE3 needs a service for a network slice that UE3 is not currently registered with, UE3 analyzes the stored availability information to determine whether the required network slice is currently available in the same VPLMN as UE3's current location, in a different FB, or in a different VPLMN as indicated (or shown) by the slice availability information. If so, UE3 triggers the registration procedure for the VPLMN and FB where the required network slice is available.

[0107] <Second Example of the First Aspect> The second example of the first aspect discloses a method in which UDM75 uses a ciphered private container between UE3 and UDM75 to provide UE3 with network slice-related information and VPLMN prioritization information during the registration procedure.

[0108] In addition, the second example of the first aspect discloses a mechanism by which UE3 provides VPLMN-related information to UDM75 during the registration procedure.

[0109] To make the second example of the first aspect understandable, the second example of the first aspect gives the same example as the first example of the first aspect as shown below.

[0110] Regarding UE3: - UE3 has installed four applications, namely APL1, APL2, APL3, and APL4, and these applications are respectively associated with network slices S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 based on the URSP rules in UE3.

[0111] - When UE3 starts the registration procedure for VPLMN1, UE3 has three active applications APL1, APL2, and APL3. That is, UE3 is interested in network slices S-NSSAI1, S-NSSAI2, and S-NSSAI3 that are permitted access by VPLMN1. The application can be represented as a service. The application can correspond to a service. For example, UE3 can activate APL1, require service 1 corresponding to APL1, and perform the registration procedure corresponding to S-NSSAI1.

[0112] Regarding VPLMN1: - Cell 501 supports network slices S-NSSAI1 and S-NSSAI2.

[0113] Regarding the HPLMN of UE3: - UDM75 has subscriber data regarding UE3 that includes S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 in the subscribed NSSAI for UE3.

[0114] The detailed process of the second example of the first aspect is as follows.

[0115] Step 0. This step is the same as step 0 in the first example of the first aspect.

[0116] In addition, UDM75 has an associated AUSF74 for UE3. This means that UE3 and AUSF74 share a common K ausf in common.

[0117] Step 1. This step is the same as step 1 in the first example of the first aspect.

[0118] In addition, UE3 holds a K ausf shared with AUSF74.

[0119] Step 2-1. This step is the same as step 2-1 in the first example of the first aspect.

[0120] Step 2-2. This step is the same as step 2-2 in the first example of the first aspect.

[0121] Step 3. UE3 sends a registration request message including user identification information, the requested NSSAI, slice availability function support, and encrypted private container parameters including Data from UE to AMF7001. The encrypted private container parameters can be represented as an encrypted private container. Data from UE can be represented as a Data from UE parameter. UE3 uses K ausf held at UE3 to encrypt Data from UE. Data from UE may include the provided NSSAI, the NSSAI of interest, location, tuned FB, UE radio functions, and slice availability function support parameters. For details of the parameters in Data from UE, reference can be made to the bullet in step 3 of the first example of the first aspect. For example, UE3 encrypts Data from UE including the provided NSSAI, the NSSAI of interest, location, tuned FB, UE radio functions, and slice availability function support parameters, and includes the ciphered Data from UE in the encrypted private container parameters.

[0122] Reference can be made to the sixth example of the first aspect for details of Data from UE.

[0123] Reference can be made to the third example of the first aspect for details regarding the encryption of Data from UE.

[0124] In step 4, AMF 7001 sends a Nudm_UECM_Registration message to UDM 75, which includes the VPLMN ID and an encrypted private container containing data from the UE. For example, the data from the UE can be encrypted data from the UE. If AMF 7001 receives slice availability function support parameters in the registration request message in step 3, AMF 7001 may include the encrypted private container in the Nudm_UECM_Registration message. For details of the parameters in the data from the UE, reference may be made to the bullet in step 4 of the first example of the first aspect. The Nudm_UECM_Registration message may include the required NSSAI received in step 3.

[0125] For example, if AMF 7001 receives a registration request message or any existing message between the AMF and the UE, or a new message between the AMF and the UE, from UE 3, AMF 7001 may send a Nudm_UECM_Registration message.

[0126] When the UDM 75 receives a Nudm_UECM_Registration message from the AMF 7001, the UDM 75 sends a Nausf_SoRDeciphering message including a SoR header and Ciphered Information to the AUSF 74, requesting the AUSF 74 to decrypt the Ciphered Information. The Ciphered Information includes data from the encrypted UE. After the AUSF 74 decrypts the data from the UE as the Ciphered Information, the UDM 75 receives a Nausf_SoRDeciphering response message including Data from UDM with clear text from the associated AUSF 74. For example, the data from the UDM with clear text may mean deciphered or unencrypted Data from UDM. For example, the data from the UDM sent from the AUSF 74 is decrypted by the AUSF 74.

[0127] Based on the information received in step 4, the UDM 75 updates the database related to the supported network slice information in the VPLMN. For example, the UDM 75 may perform the same process as step 5 in the first example of the first aspect.

[0128] Reference may be made to the third example of the first aspect for details of the interaction between the UDM 75 and the AUSF 74.

[0129] If the slice availability function support parameter is included in the encrypted private container containing data from the UE received in the Nudm_UECM_Registration message in step 4, the UDM75 sends an Nudm_UECM_Registration response message containing the encrypted private container containing data from the UDM to the AMF7001. For example, the UDM75 sends the Nudm_UECM_Registration response message after updating the DB. For example, if the UDM75 receives the Nudm_UECM_Registration message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from the AMF7001, the UDM75 may send an Nudm_UECM_Registration response message.

[0130] Data from the UDM may be represented as a Data from UDM parameter.

[0131] To generate an encrypted private container containing data from the UDM, the UDM75 sends an Nausf_SoRProtection message containing the SoR header and Steering Information to the AUSF74. The steering information includes data from the UDM with clear text. For example, the data from the UDM with clear text may mean the data from the UDM that has been decrypted or deciphered. After the AUSF74 encrypts the data from the UDM as the steering information, the UDM75 receives an Nausf_SoRProtection response message containing the encrypted data from the UDM from the AUSF74. For details of the parameters in the data from the UDM, reference may be made to the blip in step 5 of the first example of the first aspect. For example, the data from the UDM may include the slice availability information of the first example of the first aspect.

[0132] Reference may be made to the sixth example of the first aspect for details of the data from the UDM.

[0133] Step 6. AMF 7001 sends a registration approval message containing an encrypted private container including data from the UDM received in the Nudm_UECM_Registration response message from the UDM 75 in step 5 to the UE 3. For example, the data from the UDM can be data from the encrypted UDM. If AMF 7001 does not receive the slice availability function support parameters from the UE 3 in the registration request message in step 3, AMF 7001 does not include the encrypted private container in the registration approval message. The registration approval message may include at least one of a permitted NSSAI and a rejected NSSAI.

[0134] For example, if AMF 7001 receives a Nudm_UECM_Registration response message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from the UDM 75, AMF 7001 may send a registration approval message.

[0135] Step 7. Upon receiving the registration approval message from AMF 7001, UE 3 sends a registration completion message containing an encrypted private container including data from the UE to AMF 7001. UE 3 encrypts the data from the UE using K ausf held at UE 3. The data from the UE includes a rejected NSSAI, a location, and a tuned FB. For details of the parameters in the data from the UE, reference may be made to the bullet in step 7 of the first example of the first aspect. For example, UE 3 encrypts the data from the UE including a rejected NSSAI, a location, and a tuned FB, and sends a registration completion message including the encrypted data from the UE.

[0136] Step 8. When receiving a registration completion message from UE3, AMF7001 sends a Nudm_UECM_Update message containing an encrypted private container including data from the UE to UDM75. The data from the UE included in the Nudm_UECM_Update message can be the same as that received in Step 7.

[0137] Step 9. When receiving a Nudm_UECM_Update message from AMF7001, UDM75 sends a Nausf_SoRDeciphering message containing a SoR header and encryption information to AUSF74, requesting the associated AUSF74 to decrypt the encryption information. The encryption information includes the encrypted data from the UE. After AUSF74 decrypts the data from the UE as the encryption information, UDM75 receives a Nausf_SoRDeciphering response message containing the data from the UE with clear text from AUSF74. For example, the data from the UE with clear text can mean the decrypted or deciphered data from the UE.

[0138] Based on the information received in Step 8, UDM75 updates the database related to the supported network slice information in the VPLMN. For example, UDM75 can perform the same process as in Step 9 of the first example of the first aspect.

[0139] Details of the interaction between UDM75 and AUSF74 can be referred to the third example of the first aspect.

[0140] Step 10. This step is the same as Step 10 in the first example of the first aspect.

[0141] Step 11. UE3 has K in UE3 ausfUse it to decrypt the encrypted private container containing the data from the UDM received in the registration approval message in step 6, and obtain the slice availability information in clear text. For example, the slice availability information in clear text may mean the decrypted or decrypted slice availability information. UE3 performs the process as described in step 11 in the first example of the first aspect.

[0142] Step 12. This step is the same as step 12 in the first example of the first aspect.

[0143] Step 13. This step is the same as step 13 in the first example of the first aspect.

[0144] Step 14. This step is the same as step 14 in the first example of the first aspect.

[0145] <Variant 1 of the second example of the first aspect> Instead of the Nudm_UECM_Registration message in step 4, AMF7001 sends the encrypted private container containing the data from the UE to UDM75 by using the Nudm_SDM_Get message or any existing message between the AMF and the UDM, or a new message between the AMF and the UDM.

[0146] <Variant 2 of the second example of the first aspect> Instead of the Nudm_UECM_Registration response message in step 5, UDM75 sends the encrypted private container containing the data from the UDM to AMF7001 by using the Nudm_SDM_Get response message or any existing message between the AMF and the UDM, or a new message between the AMF and the UDM.

[0147] <The third example of the first aspect> The third example of the first aspect discloses a method for enabling secure data transfer from UE3 to UDM75. The third example of the first aspect can be used by other examples of the first aspect. For example, the process in the third example of the first aspect can be used in the process where UE3 and UDM75 communicate encrypted data. For example, the encrypted data can be data from the UE or data from the UDM.

[0148] The detailed process of the third example of the first aspect is as follows.

[0149] Step 1. It is assumed that UE3 and AUSF74 share a common K ausf that can be generated in the authentication procedure.

[0150] Step 2. If UE3 has data to securely transfer to UDM75, UE3 uses K ausf and a counter SoR (Counter SoR ) to encrypt the data. If UE3 requires a response from UDM75 regarding the success of the transfer, UE3 generates SoR-XMAC-I UAUSF and stores SoR-XMAC-I UAUSF in UE3.

[0151] Step 3. UE3 sends a message containing a SoR transparent container to UDM75. The SoR transparent container may include a SoR header, SoR-MAC-I UAUSF , a counter SoR , and the encrypted data. The following bullet points explain the details of each parameter.

[0152] - The SoR header indicates the format of the SoR transparent container.

[0153] - SoR-MAC-I UAUSF is the SoR-XMAC-I generated by AUSF74UAUSF It is used by the AUSF 74 to verify the received encrypted data by comparison.

[0154] - When the AUSF 74 generates the SoR-MAC-I UAUSF the counter SoR is used by the AUSF 74. The counter SoR is used as a freshness input for the derivation of the SoR-MAC-I UAUSF

[0155] - The encrypted data is the data that the UE 3 transfers to the UDM 75.

[0156] In one example, the UE 3 sends a NAS message containing a SoR transparent container to the AMF 7001, and the AMF 7001 transfers the SoR transparent container to the UDM 75.

[0157] Step 4. When receiving the SoR transparent container from the UE 3, the UDM 75 generates a Nausf_SoRDeciphering message including a Requester ID, a SUPI, a Service name, the encrypted data, the SoR-MAC-I UAUSF and the counter SoR and an ACK Indication parameter. The following bullet points explain the details of each parameter.

[0158] - The Requester ID indicates an identifier of the request for the Nausf_SoRDeciphering service.

[0159] - The SUPI is user identification information about the UE 3.

[0160] - The Service name indicates that the UDM 75 requests the decryption of the encrypted data sent from the UE 3.

[0161] ​- The -ACK indication means that UDM75 is required to send a response to UE3. When this indication is shown, AUSF74 generates SoR-XMAC-I UAUSF .

[0162] - The encrypted data, SoR-MAC-I UAUSF , and the counter SoR can be the same as those in step 3.

[0163] In one example, the Nausf_SoRDeciphering service may have different service names, such as the Nausf_SoRUnprotect service, the Nausf_SoUnlock service, or the Nausf_SoRProtection service, which have a unique service name, for example. The unique service name can be Deciphering.

[0164] In another example, the Nausf_SoRDeciphering message may have different message names, such as the Nausf_SoRUnprotect message, the Nausf_SoUnlock message, or the Nausf_SoRProtection message, which have a unique service name, for example. The unique service name can be Deciphering.

[0165] Step 5. When receiving the Nausf_SoRDeciphering message, AUSF74 generates or calculates SoR-XMAC-I UAUSF to verify whether it matches the SoR-MAC-I UAUSF value received in the Nausf_SoRDeciphering message. When the verification of SoR-XMAC-I UAUSF is successful, AUSF74 decrypts the received encrypted data. The success of the verification of SoR-XMAC-I UAUSF means that the generated (or calculated) SoR-XMAC-I UAUSF matches the SoR-MAC-I UAUSFmay mean matching the value. If an ACK indication is shown, the AUSF 74 generates SoR-XMAC-I UAUSF to generate.

[0166] Step 6. The AUSF 74 sends a Nausf_SoRDeciphering response message containing clear text data and optionally SoR-XMAC-I UAUSF to the UDM 75. The data contained in the Nausf_SoRDeciphering response message may be the date decoded by the AUSF 74 in Step 5.

[0167] In one example, the Nausf_SoRDeciphering response message may have different message names, such as a Nausf_SoRUnprotect response message, a Nausf_SoUnlock response message, or a Nausf_SoRProtection response message, having a unique service name, for example. The unique service name may be deciphering.

[0168] Step 7. When receiving the Nausf_SoRDeciphering response message from the AUSF 74, the UDM 75 uses the clear text data in the internal process in the UDM 75.

[0169] If a response is indicated from the UE 3 in Step 3, the UDM 75 sends a message containing SoR-XMAC-I UAUSF to the UE 3.

[0170] In one example, the UDM 75 sends a message containing SoR-XMAC-I UAUSF to the AMF 7001, and the AMF 7001 transfers SoR-XMAC-I UAUSF to the UE 3 using a NAS message.

[0171] Step 8. From the UDM 75 in Step 7, SoR-XMAC-I UAUSFUpon receiving it, UE3 uses the received SoR-XMAC-I to confirm that the data transfer has been successfully completed with respect to UDM75. UAUSF The UE3 compares the received SoR-XMAC-I UAUSF with the SoR-XMAC-I UAUSF that the UE3 temporarily stored in step 2. UAUSF For example, if the UE3 determines that the received SoR-XMAC-I UAUSF is the same as the SoR-XMAC-I UAUSF that the UE3 temporarily stored in step 2, the UE3 determines that the data transfer has been successfully completed with respect to UDM75. UAUSF The UE3 compares the received SoR-XMAC-I UAUSF with the SoR-XMAC-I UAUSF that the UE3 temporarily stored in step 2. UAUSF For example, if the UE3 determines that the received SoR-XMAC-I UAUSF is the same as the SoR-XMAC-I UAUSF that the UE3 temporarily stored in step 2, the UE3 determines that the data transfer has been successfully completed with respect to UDM75.

[0172] <Modification 1 of the third example of the first aspect> In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR . SoR In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR . USoR (Counter USoR ) SoR In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR . USoR In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR . USoR In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR . SoR In the third example of the first aspect, it is disclosed that a counter SoR is commonly used for two procedures such as secure data transfer from the UDM to the UE and secure data transfer from the UE to the UDM. Modification 1 discloses that secure data transfer from the UE to the UDM may have its own counter value, counter USoR (Counter USoR ). In this case, all the counters SoR appearing in the third example of the first aspect are replaced by the counter USoR . The use of the counter USoR is the same as the use of the counter SoR .

[0173] <Modification 2 of the third example of the first aspect> In the third example of the first aspect, it is disclosed that SoR-XMAC-I UAUSF is uniquely used for secure data transfer from the UE to the UDM. Modification 2 discloses that secure data transfer from the UE to the UDM may use the existing SoR-XMAC-I AUSF as defined in Non-Patent Document 8. UAUSF In the third example of the first aspect, it is disclosed that SoR-XMAC-I UAUSF is uniquely used for secure data transfer from the UE to the UDM. Modification 2 discloses that secure data transfer from the UE to the UDM may use the existing SoR-XMAC-I AUSF as defined in Non-Patent Document 8. AUSF In the third example of the first aspect, it is disclosed that SoR-XMAC-I UAUSF is uniquely used for secure data transfer from the UE to the UDM. Modification 2 discloses that secure data transfer from the UE to the UDM may use the existing SoR-XMAC-I AUSF as defined in Non-Patent Document 8.

[0174] In this case, all the SoR-XMAC-I UAUSF appearing in the third example of the first aspect are replaced by the SoR-XMAC-I AUSF . The use of SoR-XMAC-I AUSF is the same as the use of SoR-XMAC-I AUSF . UAUSF In this case, all the SoR-XMAC-I UAUSF appearing in the third example of the first aspect are replaced by the SoR-XMAC-I AUSF . The use of SoR-XMAC-I AUSF is the same as the use of SoR-XMAC-I AUSF . AUSF In this case, all the SoR-XMAC-I UAUSF appearing in the third example of the first aspect are replaced by the SoR-XMAC-I AUSF . The use of SoR-XMAC-I AUSF is the same as the use of SoR-XMAC-I AUSF . AUSFThe usage of SoR-XMAC-I UAUSF is the same as the usage of

[0175] <The fourth example of the first aspect> The fourth example of the first aspect discloses a method for enabling secure data exchange between UE3 and UDM75 using an encrypted private container.

[0176] When the HPLMN operator needs to provision the UE3 with the priority information of the VPLMN while the UE3 is roaming, the UDM75 uses the fourth example of the first aspect to provide the UE3 with the priority information of the VPLMN.

[0177] Similarly, when the UE3 needs to provision the UDM75 with VPLMN-related information, the UE3 uses the fourth example of the first aspect to provide the UDM75 with the VPLMN information.

[0178] The detailed process of the fourth example of the first aspect is as described below.

[0179] Step 1. It is assumed that the functional negotiation regarding private container handling is properly carried out among UE3, AMF7001, and UDM75.

[0180] For example, the functional negotiation is carried out in the registration procedure.

[0181] - UE3 sends a registration request message including a private container handling capability parameter to AMF7001. The private container handling capability parameter may mean that UE3 supports the private container handling function.

[0182] - AMF7001 transfers this parameter to UDM75 in the Nudm_UECM_Registration message, the Nudm_SDM_Get message, or other existing messages. If AMF7001 does not support private container handling, AMF7001 does not transfer this parameter to UDM75 in the Nudm_UECM_Registration message, the Nudm_SDM_Get message, or other existing messages, and the private container handling negotiation fails.

[0183] - UDM75 sends a Nudm_UECM_Registration response message, a Nudm_SDM_Get response message, or other existing messages that include private container handling function parameters. The private container handling function parameters may indicate whether UDM75 or the HPLMN supports the private container handling function. For example, the private container handling function parameters may indicate that UDM75 or the HPLMN supports the private container handling function. For example, the private container handling function parameters may indicate that UDM75 or the HPLMN does not support the private container handling function. For example, if UDM75 receives a Nudm_UECM_Registration message from UE3 that includes private container handling function parameters, UDM75 may include the private container handling function parameters in the Nudm_UECM_Registration response message, the Nudm_SDM_Get response message, or other existing messages. For example, if the private container handling function parameters indicate that UDM75 or the HPLMN supports the private container handling function, UDM75 may include the private container handling function parameters in the Nudm_UECM_Registration response message, the Nudm_SDM_Get response message, or other existing messages.

[0184] - AMF7001 transfers this parameter to UE3 in the registration approval message. By performing these processes between UE3 and UDM75, the function negotiation regarding private container handling is being carried out normally. When UE3 receives from UDM75 a private container handling function parameter indicating that UDM75 or HPLMN supports the private container handling function, it may mean that the function negotiation regarding private container handling is being carried out normally. When UE3 receives from UDM75 a private container handling function parameter indicating that UDM75 or HPLMN does not support the private container handling function, or when UE3 does not receive a private container handling function parameter from UDM75, it may mean that the function negotiation regarding private container handling has failed. When the function negotiation regarding private container handling is being carried out normally, UE3 may perform the process in Step 2.

[0185] In addition, UDM75 has an AUSF74 associated with UE3, and UE3 and AUSF74 share a common K ausf for sharing.

[0186] Step 2. If UE3 needs to send VPLMN information to UDM75 and UE3 recognizes that UDM75 supports private container handling, UE3 uses the K held in UE3 ausfUse it to generate an encrypted private container containing data from the UE. For example, if UE3 needs to send VPLMN information to UDM75 and UE3 recognizes that UDM75 supports private container handling, it may mean that UE3 needs to send VPLMN information to UDM75 and the functional negotiation for private container handling is successfully carried out in step 1. The VPLMN information may include the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters. The data from the UE may include the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters. For details of the parameters in the VPLMN information or the data from the UE, reference may be made to the blit in step 3 of the first example of the first aspect. For example, UE3 encrypts the data from the UE including the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, the available PLMN list, and the slice availability function support parameters, and includes the encrypted data from the UE in the encrypted private container. For example, if UE3 performs at least one of step 1 and steps 2-1 and 2-2 of the first example of the first aspect and the functional negotiation for private container handling is successfully carried out, UE3 generates an encrypted private container.

[0187] Reference may be made to the third example of the first aspect for details regarding the encryption of the data from the UE.

[0188] Step 3. UE3 sends a UL NAS transport message containing an encrypted private container including data from the UE to AMF7001. For example, the data from the UE may mean the encrypted data from the UE.

[0189] Reference may be made to the sixth example of the first aspect for details of the data from the UE.

[0190] Step 4. When the AMF 7001 receives a UL NAS transport message from the UE 3, the AMF 7001 sends a Nudm_UECM_Registration message containing an encrypted private container including data from the UE to the UDM 75. For example, the data from the UE may mean encrypted data from the UE.

[0191] Step 5. When the UDM 75 receives a Nudm_UECM_Update message from the AMF 7001, the UDM 75 sends a Nausf_SoRDeciphering message containing a SoR header and encryption information to the AUSF 74, requesting the AUSF 74 to decrypt the encryption information. The encryption information includes encrypted data from the UE. After the AUSF 74 decrypts the data from the UE as the encryption information, the UDM 75 receives a Nausf_SoRDeciphering response message containing data from the UE with clear text from the AUSF 74. For example, the data from the UE with clear text may mean decrypted or deciphered data from the UE.

[0192] Based on the information received in Step 4, the UDM 75 updates the database related to the network slice information supported in the VPLMN. For example, based on the received decrypted data from the UE, the UDM 75 may update the database related to the network slice information supported in the VPLMN. In one example, the UDM 75 may perform the operation defined in Step 5 of the first example of the first aspect. In one example, the UDM 75 may perform the operation defined in Step 9 of the first example of the first aspect.

[0193] Reference may be made to the third example of the first aspect for details of the interaction between the UDM 75 and the AUSF 74.

[0194] Step 6. If UDM75 needs to send the VPLMN prioritization information to UE3 and UDM75 recognizes that UE3 supports private container handling, UDM75 sends an Nudm_UECM_Update response message containing an encrypted private container including data from the UDM to AMF7001. For example, the VPLMN prioritization information can be slice availability information. For example, UDM75 can recognize that UE3 supports private container handling by the fact that the function negotiation for private container handling is successfully performed in Step 1. For example, if the function negotiation for private container handling is successfully performed in Step 1 and UDM75 receives an Nudm_UECM_Update message or any existing message between the UDM and the AMF or a new message between the UDM and the AMF from AMF7001, UDM75 can send an Nudm_UECM_Update response message. For example, if UDM75 receives an Nudm_UECM_Update message or any existing message between the UDM and the AMF or a new message between the UDM and the AMF from AMF7001, UDM75 can send an Nudm_UECM_Update response message. For example, if UDM75 updates the database related to the supported network slice information in the VPLMN in Step 5, UDM75 can send an Nudm_UECM_Updaten response message.

[0195] To generate an encrypted private container containing data from the UDM, the UDM 75 sends an Nausf_SoRProtection message containing the SoR header and steering information to the AUSF 74. The steering information includes data from the UDM with clear text. For example, the data from the UDM with clear text may mean the data from the UDM that has been decoded or decrypted. After the AUSF 74 encrypts the data from the UDM regarding the steering information, the UDM 75 receives an Nausf_SoRProtection response message containing the encrypted data from the UDM from the AUSF 74. The data from the UDM includes slice availability information. Regarding an example of the slice availability information in the data from the UDM, reference may be made to the blip in step 5 of the first example of the first aspect. For example, the UDM 75 may generate slice availability information in the same way as in step 5 of the first example of the first aspect.

[0196] Reference may be made to the sixth example of the first aspect for details of the data from the UDM.

[0197] Step 7. The AMF 7001 sends a DL NAS transport message containing an encrypted private container containing the data from the UDM received from the UDM 75 in the Nudm_UECM Update response message in step 6 to the UE 3. For example, the data from the UDM may mean the encrypted data from the UDM. For example, when the AMF 7001 receives an Nudm_UECM_Update response message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from the UDM 75, the AMF 7001 may send a DL NAS transport message.

[0198] Step 8. When the UE 3 receives the DL NAS transport message from the AMF 7001 in step 7, the UE 3 has the K in the UE 3 ausfUse to decrypt the encrypted private container containing data from the UDM received in the DL NAS transport message to obtain the data from the UDM in clear text. For example, the data from the UDM may mean the data from the encrypted UDM. For example, the data from the UDM in clear text may mean the data from the decrypted or decrypted UDM. UE3 performs the process as described in step 11 in the first example of the first aspect. After UE3 decrypts the encrypted private container to obtain the data from the UDM in clear text, UE3 may perform the process as described in step 11 in the first example of the first aspect.

[0199] <The fifth example of the first aspect> The fifth example of the first aspect discloses a method that enables secure data exchange between UE3 and UDM75 using an encrypted private container.

[0200] If the HPLMN operator needs to provision the VPLMN prioritization information to UE3 while UE3 is roaming, UDM75 uses the fifth example of the first aspect to provide the VPLMN prioritization information to UE3.

[0201] Similarly, if UE3 needs to provision VPLMN-related information to UDM75, UE3 uses the fifth example of the first aspect to provide the VPLMN information to UDM75.

[0202] The detailed process of the fifth example of the first aspect is as described below.

[0203] Step 1. This step is the same as step 1 in the fourth example of the first aspect.

[0204] Steps 2 and 3. If the UDM 75 needs to send the VPLMN prioritization information to the UE 3 and the UDM 75 recognizes that the UE 3 supports private container handling, the UDM 75 sends an Nudm_SMD notification message including an encrypted private container containing data from the UDM to the AMF 7001. For example, the VPLMN prioritization information may be slice availability information. For example, the UDM 75 may recognize that the UE 3 supports private container handling by the successful performance of the function negotiation for private container handling in Step 1.

[0205] To generate an encrypted private container containing data from the UDM, the UDM 75 sends an Nausf_SoRProtection message including a SoR header and steering information to the AUSF 74. The steering information includes data from the UDM with clear text. After the AUSF 74 encrypts the data from the UDM as the steering information, the UDM 75 receives an Nausf_SoRProtection response message including the encrypted data from the UDM from the associated AUSF 74. The data from the UDM includes slice availability information. For an example of the slice availability information in the data from the UDM, reference may be made to the blip in Step 5 of the first example of the first aspect. For example, the UDM 75 may generate slice availability information in the same manner as in Step 5 of the first example of the first aspect. For example, the UDM 75 may generate slice availability information based on the information included in the DB as described in the first example of the first aspect.

[0206] For example, the UDM 75 may generate, as slice availability information, a priority list of VPLMNs with supported S-NSSAIs together with FB information regarding the locations of the entire coverage of the VPLMN based on the entries in the list of roaming partners for each location. For example, the list of roaming partners may be a list of VPLMNs.

[0207] For example, the UDM 75 may generate a priority list of VPLMNs having supported S-NSSAIs together with FB information regarding the positions of the entire coverage of each VPLMN included in the list of roaming partners. For example, the list of roaming partners may be a list of VPLMNs.

[0208] For example, the UDM 75 may generate a priority list of VPLMNs having supported S-NSSAIs based on the subscribed NSSAI in the UDM 75, based on the subscribed NSSAI as slice availability information. For example, if the subscribed NSSAI for the UE 3 includes S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4, the UDM 75 may generate a priority list of VPLMNs that support S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4.

[0209] For example, when the function negotiation for private container handling is performed normally, the UDM 75 may determine that it is necessary for the UDM 75 to send the VPLMN prioritization information to the UE 3. For example, the VPLMN prioritization information may be slice availability information. The UDM 75 may send a Nudm_SMD notification message including an encrypted private container to the AMF 7001.

[0210] For example, when the content of the DB in the UDM 75 is updated, the UDM 75 may determine that it is necessary for the UDM 75 to send the VPLMN prioritization information to the UE 3. For example, the VPLMN prioritization information may be slice availability information. The UDM 75 may send a Nudm_SMD notification message including an encrypted private container to the AMF 7001.

[0211] For example, when the content of the database in UDM75 is updated, UDM75 may determine that it is necessary to send the priority information of the VPLMN to UE3. For example, the priority information of the VPLMN may be slice availability information. When the function negotiation regarding private container handling is performed normally, UDM75 may send an Nudm_SMD notification message including an encrypted private container to AMF7001.

[0212] For example, UDM75 may periodically send an Nudm_SMD notification message including an encrypted private container to AMF7001.

[0213] For example, when UDM75 is triggered to send an Nudm_SMD notification message based on the local configuration in UDM75 or the operator's policy, UDM75 may send an Nudm_SMD notification message including an encrypted private container to AMF7001.

[0214] Reference may be made to the sixth example of the first aspect for details of the data from UDM.

[0215] Step 4. AMF7001 sends a DL NAS transport message including an encrypted private container containing the data from UDM received in the Nudm_SMD notification message from UDM75 in step 3 to UE3. For example, the data from UDM may be encrypted data from UDM. For example, when AMF7001 receives an Nudm_SMD notification message or any existing message between UDM and AMF, or a new message between UDM and AMF from UDM75, AMF7001 may send a DL NAS transport message.

[0216] Step 5. When UE3 needs to send VPLMN information to UDM75 and UE3 recognizes that UDM75 supports private container handling, UE3 uses the K held in UE3 ausfIt is used to generate an encrypted private container containing data from the UE. For example, UE3 may recognize that UDM75 supports private container handling because the functional negotiation for private container handling is successfully performed in step 1. The VPLMN information may include the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters. The data from the UE may include the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters. For details of the parameters in the VPLMN information or the data from the UE, reference may be made to the blit in step 3 of the first example of the first aspect. For example, UE3 encrypts the data from the UE including the provided NSSAI, the NSSAI of interest, the location, the tuned FB, the UE radio function, and the slice availability function support parameters, and includes the encrypted data from the UE in the encrypted private container. For example, if UE3 performs at least one of step 1 and steps 2-1 and 2-2 of the first example of the first aspect and the functional negotiation for private container handling is successfully performed, UE3 generates an encrypted private container.

[0217] Reference may be made to the sixth example of the first aspect for details of the data from the UE.

[0218] Reference may be made to the third example of the first aspect for details regarding the encryption of the data from the UE.

[0219] UE3 sends a UL NAS transport message containing an encrypted private container that includes data from the UE to AMF7001. For example, the data from the UE can be encrypted data from the UE. For example, if the functional negotiation regarding private container handling is successfully performed in step 1 and UE3 receives a DL NAS transport message, UE3 can generate an encrypted private container and send a UL NAS transport message. For example, if UE3 receives a DL NAS transport message, UE3 can generate an encrypted private container and send a UL NAS transport message.

[0220] Step 6. When AMF7001 receives a UL NAS transport message from UE3, AMF7001 sends a Nudm_UECM_Update message containing an encrypted private container that includes data from the UE to UDM75. For example, the data from the UE can be encrypted data from the UE.

[0221] Step 7. When UDM75 receives a Nudm_UECM_Update message from AMF7001, UDM75 sends a Nausf_SoRDeciphering message that includes a SoR header and encryption information to AUSF74, requesting AUSF74 to decrypt the encryption information. The encryption information includes encrypted data from the UE. After AUSF74 decrypts the data from the UE as the encryption information, UDM75 receives a Nausf_SoRDeciphering response message from AUSF74 that includes data from the UE with clear text. For example, the data from the UE with clear text can mean decrypted or deciphered data from the UE.

[0222] Based on the information received in step 6, the UDM 75 updates the database related to the supported network slice information in the VPLMN. For example, based on the decoded data from the UE, the UDM 75 may update the database related to the supported network slice information in the VPLMN. In one example, the UDM 75 may perform the operations defined in step 5 of the first example of the first aspect. In one example, the UDM 75 may perform the operations defined in step 9 of the first example of the first aspect.

[0223] Reference may be made to the third example of the first aspect for details of the interaction between the UDM 75 and the AUSF 74.

[0224] Step 8. When the UE 3 receives a DL NAS transport message from the AMF 7001 in step 4, the UE 3 ausf uses K in the UE 3 to decrypt the encrypted private container containing the data from the UDM received in the DL NAS transport message and obtain the data from the UDM in clear text. For example, the data from the UDM in clear text may mean the decoded or decrypted data from the UDM. For example, the data from the UDM may mean the encrypted data from the UDM. The UE 3 performs the process as described in step 11 in the first example of the first aspect.

[0225] <Variant 1 of the fifth example of the first aspect> Instead of the DL NAS transport message in step 4, the AMF 7001 sends an encrypted private container containing the data from the UDM to the UE 3 by using a CONFIGURATION UPDATE COMMAND message.

[0226] <Variant 2 of the fifth example of the first aspect> Instead of the UL NAS transport message in step 5, UE3 sends an encrypted private container containing data from the UE to AMF7001 by using the CONFIGURATION UPDATE COMMAND COMPLETE message.

[0227] <Sixth example of the first aspect> The sixth example of the first aspect discloses examples of data from the UDM and data from the UE as described in some examples of the first aspect.

[0228] Table 1 shows some examples of data from the UDM. For example, the data from the UDM may include at least one of the parameters listed in Table 1.

Table 1

[0229] Table 2 shows some examples of data from the UE. For example, the data from the UE may include at least one of the parameters listed in Table 2. The VPLMN ID may indicate the identification information of the VPLMN in which UE3 is registered or has registered. "S-NSSAIx" may mean any S-NSSAI or any one of the S-NSSAIs.

Table 2

[0230] <Second aspect> To enable the HPLMN operator to provide the UE with accurate prioritization information of the VPLMN while the UE is roaming, the HPLMN operator needs to maintain the latest information. For example, the HPLMN operator may have a database (DB) of UE configurations and the network state at the location where the UE is roaming.

[0231] In the HPLMN, the DB is basically managed by the Operation and Maintenance (O&M) process. However, since roaming partners are spread across the world, it is very difficult to maintain the latest network configuration in the roaming partner network.

[0232] The second aspect discloses a dynamic DB update mechanism that enables the HPLMN operator to securely obtain information regarding the UE configuration and the network state at the location where the UE is roaming.

[0233] The second aspect can solve the problem that no clear mechanism is defined in the 3GPP specifications regarding how to meet the requirements in Non-Patent Document 2.

[0234] <The first example of the second aspect> The first example of the second aspect discloses how UDM75 queries information regarding the configuration of UE3 and the network state at the location where UE3 is roaming.

[0235] The detailed process of the first example of the second aspect is as follows.

[0236] Step 1. This step is the same as Step 1 in the fourth example of the first aspect.

[0237] Steps 2 and 3. UDM75 needs to obtain at least one of the configuration of UE3 and the network state at the location where UE3 is located. If UDM75 recognizes that UE3 supports private container handling, UDM75 sends an Nudm_SMD notification message containing an encrypted private container including a request from the UDM to AMF7001. For example, if the function negotiation regarding private container handling is successfully performed in Step 1, UDM75 recognizes that UE3 supports private container handling.

[0238] To generate an encrypted private container containing a request from the UDM, the UDM 75 sends an Nausf_SoRProtection message containing the SoR header and steering information to the AUSF 74. The steering information includes the request from the UDM with clear text. For example, the request from the UDM with clear text may mean a decoded or decrypted request from the UDM. After the AUSF 74 encrypts the request from the UDM as the steering information, the UDM 75 receives an Nausf_SoRProtection response message containing the encrypted request from the UDM from the AUSF 74.

[0239] For example, when the function negotiation for private container handling is performed normally, the UDM 75 may determine that it is necessary to obtain at least one of the configuration of the UE 3 and the network state at the location where the UE 3 is located. The UDM 75 may send an Nudm_SMD notification message containing the encrypted private container to the AMF 7001.

[0240] For example, when the content of the DB in the UDM 75 is updated, the UDM 75 may determine that it is necessary to obtain at least one of the configuration of the UE 3 and the network state at the location where the UE 3 is located. The UDM 75 may send an Nudm_SMD notification message containing the encrypted private container to the AMF 7001.

[0241] For example, when the content of the DB in the UDM 75 is updated, the UDM 75 may determine that it is necessary to obtain at least one of the configuration of the UE 3 and the network state at the location where the UE 3 is located. When the function negotiation for private container handling is performed normally, the UDM 75 may send an Nudm_SMD notification message containing the encrypted private container to the AMF 7001.

[0242] For example, UDM 75 may periodically send an Nudm_SMD notification message containing an encrypted private container to AMF 7001.

[0243] For example, when UDM 75 is triggered to send an Nudm_SMD notification message based on the local configuration or operator policy in UDM 75, UDM 75 may send an Nudm_SMD notification message containing an encrypted private container to AMF 7001.

[0244] Reference may be made to a second example of the second aspect for details of the request from the UDM.

[0245] Step 4. AMF 7001 sends a DL NAS transport message containing an encrypted private container including the request from the UDM received in the Nudm_SMD notification message in step 3 from UDM 75 to UE 3. For example, the request from the UDM may mean an encrypted request from the UDM. For example, when AMF 7001 receives an Nudm_SMD notification message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from UDM 75, AMF 7001 sends a DL NAS transport message.

[0246] Step 5. When receiving the DL NAS transport message from AMF 7001 in step 4, UE 3 decrypts the encrypted private container including the request from the UDM received in the DL NAS transport message using K ausf in UE 3 to obtain the request from the UDM in clear text. For example, the request from the UDM in clear text may mean a decrypted or decrypted request from the UDM.

[0247] UE3 acknowledges the request from the UDM and collects the requested information based on the request from the UDM. If UE3 needs to perform operations to collect the requested information to be provided to UDM75, UE3 may perform at least one of Registration Management (RM) procedures, Session Management (SM) procedures, scanning of the specified FB, and any other operations. The Registration Management (RM) procedure may be a provisional registration procedure for the specified VPLMN by UDM75. Refer to the second example of the second aspect for details of the requested information.

[0248] Step 6. If UE3 collects the requested information and UE3 recognizes that UDM75 supports private container handling, UE3 uses the K ausf held in UE3 to generate an encrypted private container containing data from the UE. For example, if the functional negotiation regarding private container handling is successfully performed in Step 1, UE3 recognizes that UDM75 supports private container handling. For example, the data from the UE may include the requested information.

[0249] Refer to the sixth example of the first aspect for details of the data from the UE. Refer to the second example of the second aspect for details of the data from the UE.

[0250] Refer to the third example of the first aspect for details regarding the encryption of the data from the UE.

[0251] Then, UE3 transmits a UL NAS transport message containing the encrypted private container including the data from the UE to AMF7001. For example, the data from the UE may mean the encrypted data from the UE.

[0252] Step 7. This step is the same as Step 6 in the fifth example of the first aspect.

[0253] Step 8. This step is the same as step 7 in the fifth example of the first aspect.

[0254] The request from the UDM may be represented as a request to transmit first information indicating a first network slice available in the first network where the UE3 is located, and second information indicating a second network slice required by a service or application activated in the UE3 and not available in the first network.

[0255] <Modification 1 of the first example of the second aspect> Instead of the DL NAS transport message in step 4, the AMF7001 transmits an encrypted private container including the request from the UDM to the UE3 by using a CONFIGURATION UPDATE COMMAND message.

[0256] <Modification 2 of the first example of the second aspect> Instead of the UL NAS transport message in step 6, the UE3 transmits an encrypted private container including data from the UE to the AMF7001 by using a CONFIGURATION UPDATE COMMAND COMPLETE message.

[0257] <The second example of the second aspect> The second example of the second aspect discloses an example of a request from the UDM as described in the first example of the second aspect.

[0258] Table 3 shows some examples of requests from the UDM. [Table 3]

[0259] For example, when UE3 receives a request from the UDM, UE3 sends a UL NAS transport message containing data from UE, such as at least one of UE configuration, permitted NSSAI, configured NSSAI, available NSSAI, Network Slice Simultaneous Registration Group (NSSRG) information provided by the AMF to UE3, UE context in both the SIM and the ME, quota availability, and the state of the network where UE3 is located, to AMF7001. For example, the NSSRG information can be provided to UE3 by AMF7001. For example, the UE context in both the SIM and the ME can mean the PEI (IMEISV). For example, the quota availability can mean information indicating whether a PDU session can be established with S-NSSAIx, the quota status in the VPLMN where UE3 is located, or information indicating whether the quota for the PDU session is available. For example, the state of the network where UE3 is located can mean information indicating whether S-NSSAIx is available in the 900 MHz FB.

[0260] For example, when UE3 receives a request from the UDM, UE3 sends a UL NAS transport message containing data from UE, such as at least one of the parameters listed in Table 2, to AMF7001. "S-NSSAIx" can mean any S-NSSAI or any one of the S-NSSAIs.

[0261] <The third aspect> The third aspect discloses a mechanism that enables an HPLMN operator to provide a roaming UE with network slice availability information regarding its roaming partner. For example, the network slice availability information may mean information regarding the availability of network slices for each VPLMN, for each frequency band (FB), for each RAT, and for each location. The HPLMN utilizes a database (DB) in at least one of the UDR and UDM that has network slice availability information for all roaming partners. Based on this information and the location of the roaming UE, the HPLMN creates a new URSP rule for selecting available network slices during roaming and provides the rule to the roaming UE at each registration and re-registration via URSP rule update.

[0262] The third aspect can solve the problem that no clear mechanism is defined in the 3GPP specification regarding a method capable of realizing the requirements in Non-Patent Document 2.

[0263] <The first example of the third aspect> Figure 9 depicts an example of the behavior and interaction of a UE and a network based on the disclosure of the third aspect regarding the following preliminary assumptions:

[0264] - UE3: Subscribes to network slices S-NSSAI1, S-NSSAI2, S-NSSAI3, S-NSSAI4

[0265] - VPLMN1: Cell 501 and AMF7001 support network slices S-NSSAI1 and S-NSSAI2.

[0266] - VPLMN2: Cell 502 and AMF7002 support network slice S-NSSAI4.

[0267] In step 0, the UDM 75 in the HPLMN maintains a database (DB) regarding the roaming agreements of the home operator with roaming partners of home operators from around the world. The DB may include a list of roaming partners for each location. For example, the list of roaming partners may mean a list of VPLMNs. For example, the HPLMN has roaming partners VPLMN1, VPLMN2, and VPLMN3 enumerated in order of priority in Tokyo, Japan. For each VPLMN entry in the DB, the UDM 75 may maintain one or more S-NSSAIs available at the location, along with information regarding the frequency band (FB) and RAN for which the S-NSSAI is available, for each location. The location may be a cell, a list of cells, a TA, a list of TAs, an RA, or a list of RAs. For example, in VPLMN1 in Tokyo, S-NSSAI1 and S-NSSAI2 are available in the 900 MHz frequency band, and in VPLMN2 in Tokyo, S-NSSAI4 is available.

[0268] This DB is basically managed by an operation and maintenance (O&M) process. In addition to the O&M process, the HPLMN operator may use dynamic DB updates based on an update mechanism as disclosed by the present disclosure. In addition, the UDM 75 has subscriber data regarding UE3, which includes S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4 in the subscribed NSSAI for UE3. The list of roaming partners (or the list of VPLMNs) may be the same as that for the first example of the first aspect.

[0269] In step 1, UE3 moves away from the HPLMN. UE3 triggers a registration regarding the preferred roaming partner of the HPLMN at the new location of the UE, e.g., VPLMN1.

[0270] Step 2. First, UE3 selects cell 501 belonging to VPLMN1. When selecting cell 501 from VPLMN1, UE3 may consider whether cell 501 supports the network slices required by UE3, such as S-NSSAI1 and S-NSSAI2. If cell 501 supports S-NSSAI1 and S-NSSAI2, UE3 camps on cell 501, and UE3 establishes an RRC connection with cell 501 belonging to VPLMN1. For example, based on the system information broadcast in cell 501, UE3 may consider whether cell 501 supports the network slices required by UE3. The system information may be the same as that related to step 2-1 of the first example of the first aspect.

[0271] Step 3. UE3 sends a registration request message to AMF7001 of VPLMN1. In the registration request message, UE3 includes the following:

[0272] - UE Id: Identification information of UE3 that can be 5G GUTI, SUPI, SUCI, or PEI.

[0273] - Requested NSSAI: Based on the configured NSSAI and permitted NSSAI, UE3 constructs the requested NSSAI, and may also consider URSP rules. UE3 may include the network slices supported in the PLMN in the requested NSSAI. For example, UE3 may include S-NSSAI1 and S-NSSAI2 supported by cell 501 of VPLMN1 in the requested NSSAI.

[0274] - Support indication for the registration function for the available S-NSSAI: If UE3 supports the registration function for a network slice, for example, called "available network slice" or any other indication, which is not supported by the PLMN where the UE requests registration, e.g., VPLMN1, but can be supported by a different PLMN at this location or a different frequency band (FB) at this location, or can be supported at a different location, UE3 includes the "Support for the registration function for the available S-NSSAI" indication in the registration request message. For example, if UE3 supports an S-NSSAI other than the S-NSSAI available in cell 501, UE3 may include the "Support for the registration function for the available S-NSSAI" indication in the registration request message. The "Support for the registration function for the available S-NSSAI" indication may indicate that UE3 supports an S-NSSAI other than the S-NSSAI available in cell 501.

[0275] Step 4. AMF7001 sends an Nudm_UECM_Registration message to UDM75 to register UE3 with VPLMN1. AMF7001 includes the following parameters in the Nudm_UECM_Registration message to UDM75:

[0276] - UE Id: Identification information of UE3, which can be 5G GUTI, SUPI, SUCI, or PEI.

[0277] - UE Location: When UE3 indicates "support for registration function for available S-NSSAI" in the registration request message, AMF7001 includes the UE location in the Nudm_UECM_Registration message to UDM75. For example, the UE location may mean the location of UE3. The UE location can be at the granularity of a cell, TA, or RA, for example, a global cell identification information, a list of global cell identification information, TA identification information, a list of TAs, or a location related to RA identification information. The UE location can also be NCGI, NCI, TAI, N3IWF user location information, TNGF user location information, TWIF user location information, W-AGF user location information as defined in paragraph 9.3.1.16 of Non-Patent Document 6.

[0278] - Required NSSAI: When UE3 indicates "support for registration function for available S-NSSAI" in the registration request message, AMF7001 includes the required NSSAI received from UE3, for example, S-NSSAI1 and S-NSSAI2, in the Nudm_UECM_Registration message to UDM75.

[0279] For example, when AMF7001 receives a registration request message or any existing message between the AMF and the UE, or a new message between the AMF and the UE from UE3, AMF7001 may send the Nudm_UECM_Registration message.

[0280] Based on the UE location and the required NSSAI provided by the AMF 7001, the UE network slice subscription information, and the network slice availability information in the DB, the UDM 75 constructs network slice availability information for network slices that the UE 3 is not registered for but may be interested in at some point in the future. For example, the UE location may mean the location of the UE 3. The network slices that the UE 3 is not registered for but may be interested in at some point in the future mean that the UE 3 is not registered for the network slice because the network slice is not available at the current UE location, or that the network slice is not available via the current PLMN, e.g., VPLMN1, but the UE 3 has subscribed to it and may require access at some stage, and can be referred to as available network slice(s) or any other designation for the network slice. For example, the UE 3 subscribes to S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4, but the UE is registered for S-NSSAI1 and S-NSSAI2 via VPLMN1. If the remaining S-NSSAI3 and S-NSSAI4, which the UE also subscribes to but is not registered for, are available at different locations, different frequency bands (FB), or different PLMNs according to the information from the DB in the UDM 75, these network slices S-NSSAI3 and S-NSSAI4 are considered available network slices. For example, a different PLMN may mean a VPLMN different from VPLMN1. When the UE 3 subscribes to these network slices and at some stage an application in the UE may require services from these network slices, these network slices can also be considered or referred to as "network slices of interest to the UE".Regarding these so-called "available network slices" or "network slices of interest to the UE", the UDM 75 constructs network slice availability information, for example, regarding where these network slices are available in terms of location, frequency band (FB), RAN type, or PLMN. For example, the RAN type may mean the RAT type. For example, the UDM 75 constructs network slice availability information indicating that S-NSSAI 3 and S-NSSAI 4 are available in VPLMN 2.

[0281] Step 6. The UDM 75 triggers an Nudr_DM_Notify message to the PCF 7302 in the HPLMN. The UDM 75 includes network slice availability information, for example, network slice availability information regarding network slices S-NSSAI 3 and S-NSSAI 4, in the Nudr_DM_Notify message. The UDM 75 also includes the identification information of UE3 in the UE_Id to which the network slice availability information is applicable. For example, when the UDM 75 constructs network slice availability information, the UDM 75 may send an Nudr_DM_Notify message. For example, when the UDM 75 receives an Nudm_UECM_Registration message or any existing message between the UDM and the AMF, or a new message between the UDM and the AMF from the AMF 7001, the UDM 75 may send an Nudr_DM_Notify message.

[0282] Step 7. PCF 7302 uses the network slice availability information from UDM 75 for UE 3 to update the URSP rule for UE 3. PCF 7302 may create a new entry in the URSP rule for UE 3 regarding a "usable network slice selection policy", a "network slice selection policy of UE's interest", or any other indication, which is related to a policy rule defining a list of network slices available for UE 3 along with at least one of the details of the availability of the network slice, i.e., location, frequency band (FB), RAN type, and PLMN where the network slice is available. For example, the RAN type may mean the RAT type. For example, PLMN may mean VPLMN. The "usable network slice selection policy", the "network slice selection policy of UE's interest", or any other indication related to a policy rule defining a list of network slices available for UE 3 along with the details of the availability of the network slice may be collectively referred to as the "usable network slice selection policy". For example, PCF 7302 may create a new entry indicating that S-NSSAI 3 and S-NSSAI 4 are available in VPLMN 2 and add a new entry to the URSP rule for UE 3. The "usable network slice selection policy" may indicate that S-NSSAI 3 and S-NSSAI 4 are available in VPLMN 2.

[0283] Step 8. PCF 7302 triggers an Npcf_UEPolicyControl_UpdateNotify request message to PCF 7301 in VPLMN1 where UE3 is roaming. PCF 7302 includes a new URSP rule for UE3 with an "Available Network Slice Selection Policy" in the Npcf_UEPolicyControl_UpdateNotify request message to PCF 7301, and sends the Npcf_UEPolicyControl_UpdateNotify request message to PCF 7301. For example, if PCF 7302 updates the URSP rule for UE3 in step 7, PCF 7302 may send an Npcf_UEPolicyControl_UpdateNotify request message. For example, if PCF 7302 receives a Nudr_DM_Notify message or any existing message between PCF and UDM, or a new message between PCF and UDM from UDM 75, PCF 7302 may send an Npcf_UEPolicyControl_UpdateNotify request message.

[0284] Step 9. PCF 7301 triggers an Npcf_UEPolicyControl_UpdateNotify request message to AMF 7001 of VPLMN1, and PCF 7301 includes a new URSP rule for UE 3 with an "available network slice selection policy" in the Npcf_UEPolicyControl_UpdateNotify request message. PCF 7301 sends the Npcf_UEPolicyControl_UpdateNotify request to AMF 7001. For example, if PCF 7301 receives an Npcf_UEPolicyControl_UpdateNotify request message or any existing message between PCF 7301 of the visited PLMN and PCF 7302 of the HPLMN, or a new message between PCF 7301 and PCF 7302 from PCF 7302, PCF 7301 may send the Npcf_UEPolicyControl_UpdateNotify request message. For example, the visited PLMN may mean VPLMN1.

[0285] Step 10. UDM 75 returns an Nudm_UECM_Registration response message to AMF 7001 to confirm the UE registration related to UDM 75. For example, the UE registration related to UDM 75 may mean the registration of UE 3 related to UDM 75. Step 10 may be performed after Step 6. For example, if UDM 75 sends an Nudr_DM_Notify message in Step 6, UDM 75 sends an Nudm_UECM_Registration response message.

[0286] Step 11. AMF 7001 returns a registration approval message to UE 3, and AMF 7001 includes the following parameters in the registration request message:

[0287] - Allowed NSSAI: In the allowed NSSAI, AMF 7001 returns the S-NSSAI1 and S-NSSAI2 that UE 3 has requested registration for and that are supported by VPLMN1.

[0288] - New URSP rule: When UE3 indicates the "Support for registration function for available S-NSSAI" in the registration request message, AMF7001 includes an updated URSP rule with the latest "Available network slice selection policy" in the registration approval message. For example, the new URSP rule includes an "Available network slice selection policy" indicating that S-NSSAI3 and S-NSSAI4 are available in VPLMN2.

[0289] For example, when AMF7001 receives an Npcf_UEPolicyControl_UpdateNotify request message at step 9 or any existing message between PCF and AMF, or a new message between PCF and AMF from PCF7301, AMF7001 may send a registration approval message.

[0290] For example, when AMF7001 receives an Nudm_UECM_Registration response message or any existing message between UDM and AMF, or a new message between UDM and AMF from UDM75, AMF7001 may send a registration approval message.

[0291] For example, when AMF7001 receives at least one of the Npcf_UEPolicyControl_UpdateNotify request message and the Nudm_UECM_Registration response message at step 9, AMF7001 may send a registration approval message.

[0292] Step 12. UE3 stores the received URSP rules with the updated "Available Network Slice Selection Policy". If an application in UE3 requires a service in one of the available network slices, for example, in S-NSSAI4, UE3 analyzes the "Available Network Slice Selection Policy" within the URSP rules to check whether the network slice required by the application is available at the location of UE3 in the same FB, RAN, or PLMN, or in a different FB, different RAN, or different PLMN. If the required network slice is available at the UE location, UE3 triggers the registration procedure for S-NSSAI4 in VPLMN2. For example, if the required network slice is available at the UE location, it may mean that S-NSSAI4 is available in VPLMN2. For example, the UE location may mean the location of UE3.

[0293] Step 13. UE3 selects a cell in VPLMN2, for example, cell 502, and UE3 sends a registration request message to AMF7002 in VPLMN2. UE3 includes S-NSSAI4 in the required NSSAI. UE3 also includes the indication of "Support for Registration Function for Available S-NSSAI" in the registration request message to AMF7002 in VPLMN2.

[0294] Step 14. The registration procedure continues with step 4 in section 4.2.2.2.2 of 3GPP TS23.502 for AMF7002 in VPLMN2.

[0295] The required NSSAI may be represented as first information indicating the first network slice for which UE3 requests registration in the first network. The "Available Network Slice Selection Policy" may be represented as second information indicating a second network slice that is a network slice subscribed by UE3 and is different from the first network slice and is available in the second network.

[0296] <Modification 1 of the first example of the third aspect> In step 4 of FIG. 9, AMF 7001 may not include the required NSSAI in the Nudm_UECM_Registration message to UDM 75. In this case, UDM 75 constructs network slice availability information based on the database available in UDM 75 for all network slices subscribed by UE 3, including the network slices in the required NSSAI. For example, if the UE subscribes to S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4, UDM 75 constructs network slice availability information for S-NSSAI1, S-NSSAI2, S-NSSAI3, and S-NSSAI4.

[0297] <Modification 2 of the first example of the third aspect> In step 11 of FIG. 9, AMF 7001 may also convey a new URSP rule with an updated "available network slice selection policy" to UE 3 via a UE Configuration Update (UCU) message if UE 3 is in the connected mode. For example, instead of the registration approval message in step 11, AMF 7001 may convey a new URSP rule with an updated "available network slice selection policy" to UE 3 via a UE Configuration Update (UCU) message if UE 3 is in the connected mode.

[0298] If UE 3 is in the idle mode, AMF 7001 may page UE 3 to bring UE 3 to the connected mode, and AMF 7001 conveys a URSP rule with an updated "available network slice selection policy" to UE 3 via a UE Configuration Update (UCU) message.

[0299] <Modification 3 of the first example of the third aspect> In step 7, the PCF7302 may include a validity restriction while constructing the "Available Network Slice Selection Policy" within the URSP rule for the UE3. The validity restriction can be a restriction in terms of time. For example, the network slice may be available only at a specific time, or the network slice may be available for a specific period. The validity restriction can be for each specific network slice within the "Available Network Slice Selection Policy", or it can be generally for the "Available Network Slice Selection Policy". When the validity restriction is set within or for the "Available Network Slice Selection Policy", the UE3 takes this validity restriction into account when the request for the available network slice is required by the application in the UE3. For example, if the validity restriction indicates that the "Available Network Slice Selection Policy" is valid until a specific date, the UE3 checks whether the current date is within the specific date indicated by the validity restriction. For example, if the specific date is January 2022 and the current date is December 2021, the UE3 may check or determine whether the current date is within the specific date. If the UE3 determines that the current date is within the specific date indicated by the validity restriction, the UE3 may perform the registration procedure for the S-NSSAI indicated by the "Available Network Slice Selection Policy".

[0300] <System Overview> FIG. 10 schematically shows a telecommunication system 1 for mobile (cellular or wireless) to which the above aspect is applicable.

[0301] The telecommunication system 1 represents a system overview enabling end-to-end communication. For example, the UE3 (or user equipment, "mobile device" 3) communicates with other UE3s or service servers within the data network 20 via respective (R)AN nodes 5 and the core network 7.

[0302] (R)AN node 5 supports any wireless access, and the any wireless access includes non-3GPP RATs including 5G radio access technology (RAT), E-UTRA radio access technology, Beyond5G RAT, 6G RAT, and wireless local area network (WLAN) technologies as defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0303] (R)AN node 5 can be separated into a Radio Unit (RU), a Distributed Unit (DU), and a Centralized Unit (CU). In some aspects, each part may be connected to each other by adopting an architecture as defined by the Open RAN (O-RAN) Alliance to construct (R)AN node 5, and the above parts are respectively referred to as O-RU, O-DU, and O-CU.

[0304] (R)AN node 5 can be separated into a control plane function and a user plane function. Further, multiple user plane functions can be allocated to support communication. In some aspects, user traffic may be distributed among multiple user plane functions, and the user traffic in each user plane function is aggregated at both UE3 and (R)AN node 5. This separation architecture may be called "dual connectivity" or "multi-connectivity".

[0305] (R)AN node 5 can also support communication using satellite access. In some aspects, (R)AN node 5 can support satellite access and terrestrial access.

[0306] In addition, the (R)AN node 5 can also be referred to as an access node for non-wireless access. Non-wireless access includes fixed network access as defined by the Broadband Forum (BBF) and optical access as defined by the Innovative Optical and Wireless Network (IOWN).

[0307] The core network 7 can include logical nodes (or "functions") that support communications in the telecommunications system 1. For example, the core network 7 can be a 5G Core Network (5GC) that includes, among other functions, control plane functions and user plane functions. Each function in the logical node can be regarded as a network function. The network function can be provided to another node by adapting the Service Based Architecture (SBA).

[0308] The network function can be deployed as a distributed, redundant, stateless, and scalable one that provides services from several locations and provides several execution instances at each location by adapting network virtualization technologies as defined by the European Telecommunications Standards Institute, Network Functions Virtualization (ETSI NFV).

[0309] The core network 7 can support a Non-Public Network (NPN). The NPN can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0310] As is well known, when the UE3 is moving around the geographical area covered by the telecommunication system 1, the UE3 can enter and exit the area (i.e., the radio cell) served by the (R)AN node 5. To maintain the tracking of the UE3 and facilitate the movement between various (R)AN nodes 5, the core network 7 includes at least one access and mobility management function (AMF) 70. The AMF 70 communicates with the (R)AN node 5 connected to the core network 7. In some core networks, a mobility management entity (MME) or a mobility management node for Beyond 5G, or a mobility management node for 6G, may be used instead of the AMF 70.

[0311] The core network 7 also includes, in particular, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, a Network Exposure Function (NEF) 74, a Unified Data Management (UDM) 75, and a Network Data Analytics Function (NWDAF) 76. When the UE3 roams to a visited Public Land Mobile Network (VPLMN), the home Public Land Mobile Network (HPLMN) of the UE3 provides the UDM 75 and at least a part of the functions of the SMF 71, the UPF 72, and the PCF 73 to the roaming-out UE3.

[0312] UE3 and each serving (R)AN node 5 are connected via an appropriate air interface (e.g., the so-called "Uu" interface and / or the like). Adjacent (R)AN nodes 5 are connected to each other via an appropriate (R)AN node 5-to-(R)AN node interface (such as the so-called "Xn" interface and / or the like). Each (R)AN node 5 is also connected to a node within the core network 7 (such as a so-called core network node) via an appropriate interface (such as the so-called "N2" / "N3" interface and / or the like). A connection to the data network 20 is also provided from the core network 7. The data network 20 can be the Internet, a public network, an external network, a private network, or an internal network of a PLMN. When the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), IP Multimedia Subsystem (IMS) services can be provided by that data network 20. UE3 can be connected to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or an unstructured data type.

[0313] The "Uu" interface may include a control plane of the Uu interface and a user plane of the Uu interface.

[0314] The user plane of the Uu interface is responsible for transmitting user traffic between UE3 and the serving (R)AN node 5. The user plane of the Uu interface may have a hierarchical structure with SDAP, PDCP, RLC, and MAC sublayers by means of a physical connection.

[0315] The control plane of the Uu interface is responsible for establishing, modifying, and releasing the connection between the UE 3 and the serving (R)AN node 5. The control plane of the Uu interface may have a hierarchical structure with RRC, PDCP, RLC, and MAC sublayers by means of a physical connection.

[0316] For example, the following messages are communicated in the RRC layer to support AS signaling.

[0317] - RRC Setup Request message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the RRC Setup Request message. -- establishmentCause and ue-Identity. The ue-Identity may have a value of ng-5G-S-TMSI-Part1 or a randomValue.

[0318] - RRC Setup message: This message is sent from the (R)AN node 5 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the RRC Setup message. -- masterCellGroup and radioBearerConfig

[0319] - RRC setup complete message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the RRC setup complete message. --guami-Type, iab-NodeIndication, idleMeasAvailable, mobilityState, ng-5G-S-TMSI-Part2, registeredAMF, selectedPLMN-Identity

[0320] UE3 and AMF70 are connected via an appropriate interface (e.g., the so-called N1 interface and / or the like). The N1 interface serves to provide communication between UE3 and AMF70 to support NAS signaling. The N1 interface can be established in 3GPP access and non-3GPP access. For example, the following messages are communicated on the N1 interface.

[0321] - Registration request message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the registration request message. --5GS registration type, ngKSI, 5GS mobile identity, Non-current native NAS key set identifier, 5GMM capability, UE security capability, Requested NSSAI, Last visited registered TAI, S1 UE network capability, Uplink data status, PDU session status, MICO indication, UE status, Additional GUTI, Allowed PDU session status, UE's usage setting, Requested DRX parameters, EPS NAS message container, LADN indication, Payload container type, Payload container, Network slicing indication, 5GS update type, Mobile station classmark 2, Supported codecs, NAS message container, EPS bearer context status, Requested extended DRX parameters, T3324 value, UE radio capability IDID), Requested mapped NSSAI, Additional information requested, Requested WUS assistance information, N5GC indication, and Requested NB-N1 mode DRX parameters.

[0322] - Registration accept message: This message is sent from AMF 70 to UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the registration accept message. --5GS registration result, 5G-GUTI, Equivalent PLMNs, TAI list, Allowed NSSAI, Rejected NSSAI, Configured NSSAI, 5GS network feature support, PDU session status, PDU session reactivation result, PDU session reactivation result error cause, LADN information, MICO indication, Network slicing indication, Service area list, T3512 value, Non-3GPP de-registration timer value, T3502 value, Emergency number list, Extended emergency number list, SOR transparent container, EAP message, NSSAI inclusion mode, Operator-defined access category definitions, Negotiated DRX parameters, Non-3GPP NW policies, EPS bearer context status, Negotiated extended DRX parameters, T3447 value, T3448 valuevalue), T3324 value, UE radio capability ID, UE radio capability ID deletion indication, Pending NSSAI, Ciphering key data, CAG information list, Truncated 5G-S-TMSI configuration, Negotiated WUS assistance information, Negotiated NB-N1 mode DRX parameters, and Extended rejected NSSAI.

[0323] - Registration Complete message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the Registration Complete message. -- SOR transparent container.

[0324] - Authentication Request message: This message is sent from AMF70 to UE3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the Authentication Request message. -- ngKSI, ABBA, Authentication parameter RAND (5G authentication challenge), Authentication parameter AUTN (5G authentication challenge), and EAP message.

[0325] - Authentication Response message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the authentication response message. -- Authentication response message identity, Authentication response parameter, and EAP message.

[0326] - Authentication Result message: This message is sent from AMF70 to UE3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the authentication result message. -- ngKSI, EAP message, and ABBA.

[0327] - Authentication Failure message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the authentication failure message. -- Authentication failure message identity, 5GMM cause, and Authentication failure parameter.

[0328] - Authentication Reject message: This message is sent from AMF70 to UE3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the authentication reject message. -- EAP message.

[0329] - Service Request message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the Service Request message. -- ngKSI, Service type, 5G-S-TMSI, Uplink data status, PDU session status, Allowed PDU session status, NAS message container.

[0330] - Service Accept message: This message is sent from AMF70 to UE3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the Service Accept message. -- PDU session status, PDU session reactivation result, PDU session reactivation result error cause, EAP message, and T3448 value.

[0331] - Service Reject message: This message is sent from AMF70 to UE3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may coexist within the Service Reject message. -- 5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list.

[0332] - Configuration Update Command message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may co-exist within the Configuration Update Command message. -- Configuration update indication, 5G-GUTI, TAI list, Allowed NSSAI, Service area list, Full name for network, Short name for network, Local time zone, Universal time and local time zone, Network daylight saving time, LADN information, MICO indication, Network slicing indication, Configured NSSAI, Rejected NSSAI, Operator-defined access category definitions, SMS indication, T3447 value, CAG information list, UE radio capability ID, UE radio capability ID deletion indication, 5GS registration result, Truncated 5G-S-TMSI configuration, Additional configuration indication, and Extended rejected NSSAI.

[0333] - Configuration Update Complete message: This message is sent from UE3 to AMF70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may co-exist within the Configuration Update Complete message. -- Configuration update complete message identity.

[0334] <User equipment (UE)> FIG. 11 is a block diagram showing the main components of UE3 (Mobile Device 3). As shown, UE3 includes a transceiver circuit 31, which is operable to transmit signals to and receive signals from a connection node via one or more antennas 32. Further, UE3 may include a user interface 34 for inputting information from the outside or outputting information to the outside. Although not necessarily shown in the figure, UE3 may have all the normal functions of a conventional mobile device, which may be provided by any one or any combination of hardware, software, and firmware as needed. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunication network or from a removable data storage device (RMD). The controller 33 controls the operation of UE3 according to the software stored in the memory 36. The software particularly includes an operating system 361 and a communication control module 362 having at least a transceiver control module 3621. The communication control module 362 (using its transceiver control module 3621) is responsible for processing (generating / sending / receiving) signaling and uplink / downlink data packets between UE3 and other nodes such as (R)AN node 5 and AMF 70. Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) regarding access and mobility management procedures (for UE3). The controller 33 interacts with one or more Universal Subscriber Identity Modules (USIMs) 35. When provided with a plurality of USIMs 35, the controller 33 may activate only one USIM 35 or may activate a plurality of USIMs 35 simultaneously.

[0335] UE3 can support, for example, a Non-Public Network (NPN). The NPN can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0336] UE3 can be, for example, an item of equipment for production or manufacturing, and / or an item of energy-related machinery (such as boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal power generators, nuclear power generators, batteries, nuclear systems and / or related equipment, heavy electrical machinery, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machinery, manipulators, robots and / or their application systems, tools, molds or dies, rolls, conveying equipment, lifting equipment, material handling equipment, textile machinery, sewing machinery, printing machinery and / or related machinery, paper-making machinery, chemical machinery, mining machinery and / or construction machinery and / or related equipment, machinery and / or appliances for agriculture, forestry, and / or fishing, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, pipe fittings, and / or application systems for any of the aforementioned equipment or machinery).

[0337] UE3 can be, for example, an item of transportation equipment (such as vehicles, automobiles, motorcycles, bicycles, trains, buses, trucks, rickshaws, ships and other vessels, aircraft, rockets, satellites, drones, balloons, etc.).

[0338] UE3 can be, for example, an item of information and communication equipment (such as electronic computers and related equipment, communication and related equipment, electronic components, etc.).

[0339] UE3 can be, for example, a refrigeration machine, a refrigeration machine application product, an item of equipment for commercial and / or service industries, a vending machine, an automatic service machine, an office machine or equipment, a consumer electronics device and appliance (e.g., consumer electronics appliances such as audio equipment, video equipment, loudspeakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, electric fans or related appliances, vacuum cleaners, etc.).

[0340] UE3 can be, for example, an electrical application system or equipment (e.g., an electrical application system or equipment such as an x-ray system, a particle accelerator, a radioisotope device, a sonic device, an electromagnetic application device, an electrical power application device, etc.).

[0341] UE3 can be, for example, an electronic lamp, a lighting fixture, a measuring instrument, an analyzer, a testing machine, or a surveying or detection device (e.g., a surveying or detection device such as a smoke alarm, a people alarm sensor, a motion sensor, a wireless tag, etc.), a wristwatch or a wall clock, laboratory equipment, an optical device, a medical device and / or system, a weapon, an item of cutlery, a hand tool, or the like.

[0342] UE3 can be, for example, a wireless equipped personal digital assistant or related equipment (such as a wireless card or module designed to be attached to or inserted into another electronic device (e.g., a personal computer, an electrical measuring machine)).

[0343] UE3 can be part of a device or system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below with respect to the "internet of things (IoT)".

[0344] An Internet of Things device (or "Thing") may comprise suitable electronic devices, software, sensors, network connectivity, and / or the like, whereby the device can collect and exchange data with each other and with other communication devices. An IoT device may comprise automated equipment that follows software instructions stored in internal memory. An IoT device can operate without the need for human supervision or interaction. An IoT device can also remain stationary and / or powered off for long periods of time. An IoT device can be implemented as part of a (generally) fixed installation. An IoT device can also be incorporated into a non-fixed device (e.g., a vehicle) or attached to an animal or person being monitored / tracked.

[0345] It will be understood that IoT technology can be implemented on any communication device that can connect to a communication network that transmits / receives data, regardless of whether such communication device is controlled by human input or by software instructions stored in memory.

[0346] It will be understood that IoT devices are sometimes also referred to as Machine-Type Communication (MTC) devices or Machine-to-Machine (M2M) communication devices, or Narrow Band-IoT UEs (NB-IoT UEs). It will be understood that UE3 can support one or more IoT or MTC applications.

[0347] UE3 can be a smartphone or a wearable device (e.g., smart glasses, smartwatch, smart ring, or hearable device).

[0348] UE3 can be a vehicle, a connected car, a self-driving vehicle, a vehicle device, a motorcycle, or a Vehicle to Everything (V2X) communication module (for example, a vehicle-to-vehicle communication module, a vehicle-to-infrastructure communication module, a vehicle-to-person communication module, and a vehicle-to-network communication module).

[0349] <(R)AN node> FIG. 12 is a block diagram showing the main components of an exemplary (R)AN node 5, for example, a base station (such as an "eNB" in LTE, a "gNB" in 5G, a base station for Beyond 5G, a base station for 6G). As shown, the (R)AN node 5 includes a transceiver circuit 51, and the transceiver circuit 51 is operable to transmit signals to and receive signals from a connected UE3 via one or more antennas 52, and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 53. A controller 54 controls the operation of the (R)AN node 5 according to software stored in a memory 55. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software particularly includes an operating system 551 and a communication control module 552 having at least a transceiver control module 5521.

[0350] The communication control module 552 (using its transceiver control sub-module) is responsible for processing (generating / sending / receiving) signaling between the (R)AN node 5 and other nodes such as the UE 3, another (R)AN node 5, the AMF 70, and the UPF 72, either directly or indirectly. The signaling may include, for example, properly formatted signaling messages related to the radio connection and connection with the core network 7 for a particular UE 3, especially those related to connection establishment and maintenance, such as RRC connection establishment messages and other RRC messages, NG Application Protocol (NGAP) messages (i.e., messages at the N2 reference point), Xn application protocol (XnAP) messages (i.e., messages at the Xn reference point), etc. Such signaling may also include, in the case of transmission, for example, broadcast information (such as master information and system information).

[0351] When implemented, the controller 54 is also configured (either by software or hardware) to process related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0352] (R)AN node 5 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The Master Node (MN) 501 and the Secondary Node (SN) 502 may have the same components as the (R)AN node 5.

[0353] <System Overview of (R)AN Node 5 Based on the O-RAN Architecture> FIG. 13 schematically shows an (R)AN node 5 based on an O-RAN architecture to which the (R)AN node 5 mode is applicable.

[0354] The (R)AN node 5 based on the O-RAN architecture represents a system overview in which the (R)AN node is separated into a radio unit (RU) 60, a distributed unit (DU) 61, and a centralized unit (CU) 62. In some modes, each part may be combined. For example, the RU 60 may be integrated / combined with the DU 61 as an integration / combination part, and the DU 61 may be integrated / combined with the CU 62 as another integration / combination part. Any function in the description of a certain part (for example, one of the RU 60, the DU 61, and the CU 62) may be implemented in the above integration / combination part. Further, the CU 62 may be separated into two functional parts such as a CU control plane (CP) and a CU user plane (UP). The CU CP has a control plane function in the (R)AN node 5. The CU UP has a user plane function in the (R)AN node 5. Each CU CP is connected to the CU UP via an appropriate interface (such as the so-called "E1" interface and / or the like).

[0355] UE3 and each serving RU60 are connected via an appropriate air interface (e.g., the so-called "Uu" interface and / or the like). Each RU60 is connected to DU61 via an appropriate interface (such as the so-called "front haul", "open front haul", "F1" interface, and / or the like). Each DU61 is connected to CU62 via an appropriate interface (such as the so-called "mid haul", "open mid haul", "E2" interface, and / or the like). Each CU62 is also connected to a node within core network 7 (such as a so-called core network node) via an appropriate interface (such as the so-called "back haul", "open back haul", "N2" / "N3" interface, and / or the like). Additionally, the user plane portion of DU61 may also be connected to core network node 7 via an appropriate interface (such as the so-called "N3" interface and / or the like).

[0356] Depending on the functions separated among RU60, DU61, and CU62, each part provides a part of the functions provided by (R)AN node 5. For example, RU60 may provide a function of communicating with UE3 at the air interface, DU61 may provide a function of supporting the MAC layer and the RLC layer, and CU62 may provide a function of supporting the PDCP layer, the SDAP layer, and the RRC layer.

[0357] <Radio Unit (RU)> FIG. 14 is a block diagram showing the main components of the RU part of an exemplary RU60, for example, a base station (e.g., "eNB" in LTE, "gNB" in 5G, a base station for Beyond 5G, a base station for 6G). As shown, RU60 includes a transceiver circuit 601, which is operable to transmit signals to and receive signals from a connected UE3 via one or more antennas 602, and to transmit signals to and receive signals from other network nodes or network parts (directly or indirectly) via a network interface 603. A controller 604 controls the operation of RU60 according to software stored in a memory 605. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software particularly includes an operating system 6051 and a communication control module 6052 having at least a transceiver control module 60521.

[0358] The communication control module 6052 (using its transceiver control sub-module) is responsible for processing (generating / sending / receiving) signaling between RU60 and other nodes or parts such as UE3, another RU60, and DU61 (e.g., directly or indirectly). The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connection with (for a particular UE3) RU60, particularly related to the MAC layer and the RLC layer.

[0359] The controller 604 is also configured (by software or hardware) to process related tasks such as UE mobility estimation and / or movement trajectory estimation when implemented.

[0360] The RU60 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0361] As described above, the RU60 may be integrated / connected to the DU61 as an integration / connection part. Any function in the description of the RU60 may be implemented in the above integration / connection part.

[0362] <Distributed Unit (DU)> FIG. 15 is a block diagram showing the main components of an exemplary DU61, e.g., the DU part of a base station (such as an "eNB" in LTE, a "gNB" in 5G, a base station for Beyond 5G, a base station for 6G). As shown, the apparatus includes a transceiver circuit 611, and the transceiver circuit 611 is operable to transmit signals to and receive signals from other nodes or parts (including the RU60) via a network interface 612. A controller 613 controls the operation of the DU61 according to software stored in a memory 614. For example, the software may be pre-installed in the memory 614 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, in particular, an operating system 6141 and a communication control module 6142 having at least a transceiver control module 61421. The communication control module 6142 (using its transceiver control module 61421) is responsible for processing (generating / sending / receiving) signaling between the DU61 and other nodes or parts such as the RU60 and other nodes or parts.

[0363] DU61 can support a Non-Public Network (NPN). The NPN can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0364] As described above, RU60 can be integrated / connected to DU61 or CU62 as an integration / connection part. Any function in the description of DU61 can be implemented in one of the above integration / connection parts.

[0365] <Centralized Unit (CU)> Figure 16 is a block diagram showing the main components of an exemplary CU62, e.g., the CU part of a base station (such as "eNB" in LTE, "gNB" in 5G, a base station for Beyond 5G, a base station for 6G). As shown, the apparatus includes a transceiver circuit 621, which is operable to transmit signals to and receive signals from other nodes or parts (including DU61) via a network interface 622. A controller 623 controls the operation of CU62 according to software stored in a memory 624. For example, the software may be pre-installed in the memory 624 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, in particular, an operating system 6241 and a communication control module 6242 having at least a transceiver control module 62421. The communication control module 6242 (using its transceiver control module 62421) is responsible for processing (generating / sending / receiving) signaling between CU62 and other nodes or parts such as DU61 and other nodes or parts.

[0366] CU62 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0367] As described above, CU62 may be integrated / connected to DU61 as an integration / connection unit. Any function in the description of CU62 may be implemented in the above integration / connection unit.

[0368] <amf> FIG. 17 is a block diagram showing the main components of the AMF70. As shown, the apparatus includes a transceiver circuit 701, which is operable to transmit signals to other nodes (including UE3) and receive signals from other nodes (including UE3) via a network interface 702. A controller 703 controls the operation of the AMF70 according to software stored in a memory 704. For example, the software may be pre-installed in the memory 704 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software particularly includes an operating system 7041 and a communication control module 7042 having at least a transceiver control module 70421. The communication control module 7042 (using its transceiver control module 70421) is responsible for handling (generating / sending / receiving) signaling between the AMF70 and other nodes such as UE3 (e.g., via an (R)AN node 5) and other core network nodes including core network nodes in the HPLMN of UE3 when UE3 is roaming in. Such signaling may include appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for UE3).

[0369] The AMF70 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The AMF7001 and AMF7002 may have the same components as the AMF70.

[0370] <pcf> Figure 18 is a block diagram showing the main components of the PCF73. As shown, the apparatus includes a transceiver circuit 731 which is operable to transmit signals to and receive signals from other nodes (including the AMF70) via a network interface 732. A controller 733 controls the operation of the PCF73 according to software stored in a memory 734. For example, the software may be preinstalled in the memory 734 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software particularly includes an operating system 7341 and a communication control module 7342 having at least a transceiver control module 73421. The communication control module 7342 (using its transceiver control module 73421) is responsible for processing (generating / sending / receiving) signaling between the PCF73 and other nodes such as the AMF70 and other core network nodes including core network nodes in the HPLMN of the UE3 when the UE3 is roaming in. Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP RESTful methods based on a service-based interface) regarding policy management procedures (for the UE3).

[0371] The PCF73 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The PCF7301 and the PCF7302 may have the same components as the PCF73.

[0372] <ausf> FIG. 19 is a block diagram showing the main components of the AUSF 74. As shown, the apparatus includes a transceiver circuit 741, which is operable to transmit signals to and receive signals from other nodes (including the UDM 75) via a network interface 742. The controller 743 controls the operation of the AUSF 74 according to software stored in the memory 744. For example, the software may be pre-installed in the memory 744 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software particularly includes an operating system 7441 and a communication control module 7442 having at least a transceiver control module 74421. The communication control module 7442 (using its transceiver control module 74421) is responsible for processing (generating / sending / receiving) signaling between the AUSF 74 and other nodes such as the AMF 70 and other core network nodes including the core network nodes in the HPLMN of the UE 3 when the UE 3 is roaming in. Such signaling may include, for example, properly formatted signaling messages (e.g., HTTP RESTful methods based on a service-based interface) regarding policy management procedures (for the UE 3).

[0373] The AUSF 74 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0374] <udm> Figure 20 is a block diagram showing the main components of the UDM75. As shown, the apparatus includes a transceiver circuit 751, which is operable to transmit signals to and receive signals from other nodes (including the AMF70) via a network interface 752. A controller 753 controls the operation of the UDM75 according to software stored in a memory 754. For example, the software may be pre-installed in the memory 754 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, in particular, an operating system 7541 and a communication control module 7542 having at least a transceiver control module 75421. The communication control module 7542 (using its transceiver control module 75421) is responsible for processing (generating / sending / receiving) signaling between the UDM75 and other nodes such as the AMF70 and other core network nodes including core network nodes in the VPLMN of the UE3 when the UE3 is roaming out. Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP RESTful methods based on a service-based interface) related to mobility management procedures (for the UE3).

[0375] The UDM75 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0376] <Modifications and Alternatives> Detailed aspects have been described above. Nevertheless, those skilled in the art will understand that numerous modifications and alternatives can be made to the above aspects while still receiving the benefits of the disclosure embodied herein. By way of mere example, numerous such alternatives and modifications are described herein.

[0377] In the above description, UE3 and the network device are described to facilitate understanding as having a number of separate modules (such as a communication control module). These modules can thus be provided, for example, for a particular application where an existing system is modified to implement the present disclosure, or in other applications, for example, in a system designed from the start considering the features of the invention. However, since these modules may be built into the overall operating system or code, these modules may not need to be recognized as separate entities. These modules can also be implemented in software, hardware, firmware, or a combination thereof.

[0378] Each controller may comprise a processing circuit in any suitable form, for example, one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (IO) circuits, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control bus, data bus, and / or address bus), direct memory access (DMA) functionality, hardware or software-implemented counters, pointers and / or timers, and / or the like (but not limited thereto).

[0379] In the above aspect, a number of software modules were described. Those skilled in the art will understand that the software modules may be provided in a compiled or non-compiled form, and may be supplied to the UE3 and network devices as signals in a computer network or on a recording medium. Further, the functions performed by some or all of the software may be performed using one or more dedicated hardware circuits. However, software modules are preferably used to update the functions of the UE3 and network devices in order to facilitate the update of the UE3 and network devices.

[0380] In the above aspect, 3GPP radio communication (radio access) technology is used. However, any other radio communication technology (e.g., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed-line communication technologies (e.g., BBF access, cable access, optical access, etc.) may also be used according to the above aspect.

[0381] Items of user equipment may include communication devices such as, for example, mobile phones, smartphones, user equipment, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, and / or the like. Such mobile (and generally fixed) devices are usually operated by a user, but it is also possible to connect so-called "Internet of Things" (IoT) devices and similar machine-type communication (MTC) devices to the network. For the sake of simplicity, this application refers to mobile devices (or UEs) in the description, but it will be understood that the technology described may be implemented on any (mobile and / or generally fixed) communication device that can connect to a communication network to transmit / receive data, regardless of whether such a communication device is controlled by human input or by software instructions stored in memory.

[0382] Various other modifications will be apparent to those skilled in the art and are not described in further detail herein.

[0383] As will be understood by those skilled in the art, the present disclosure may be embodied as a method and system. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0384] It will be understood that each block of the block diagrams may be implemented by computer program instructions. The computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions executed via the processor of the computer or other programmable data processing apparatus create means for implementing the functions / acts specified in the flowchart and / or block or blocks of the block diagrams. The general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a plurality of microprocessors, one or more microprocessors in combination with other devices, or any other such configuration.

[0385] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium may be connected to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC.

[0386] The previous description of the examples of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the examples will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is not intended to be limited to the examples shown herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0387] The present disclosure has been described in detail with reference to exemplary embodiments thereof, but the present disclosure is not limited to such embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined herein. For example, the above embodiments are not limited to 5GS, and the embodiments are also applicable to communication systems other than 5GS (for example, 6G systems, Beyond 5G systems).

[0388] <Appendix> All or part of the exemplary embodiments of the above disclosure may be described as follows, but are not limited to the following appendix.

[0389] Appendix 1. A method for a user equipment (UE), comprising: transmitting first information indicating a first network slice available in a first network where the UE is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network; receiving third information indicating a second network where the second network slice is available; a method.

[0390] Appendix 2. Further, performing a registration procedure for the second network; The method according to Appendix 1.

[0391] Appendix 3. The first information is included in the registration request message, The second information is included in the registration approval message, The method according to Appendix 1 or 2.

[0392] Appendix 4. The first information and the second information are encrypted, The method according to any one of Appendices 1 to 3.

[0393] Appendix 5. A method of a communication device, receiving first information indicating a first network slice available in a first network where a user equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network, transmitting third information indicating a second network where the second network slice is available, Method.

[0394] Appendix 6. Further, storing the first information and the second information, The method according to Appendix 5.

[0395] Appendix 7. The communication device is a Unified Data Management (UDM), The method according to Appendix 5 or 6.

[0396] Appendix 8. A method of a user equipment (UE), receiving first information indicating a first network where a first network slice is available, After receiving the first information, transmit second information indicating a second network slice that is available in a second network in which the UE is located, and third information indicating the first network slice that is required by a service or application that is active in the UE and that is not available in the second network. Method.

[0397] Appendix 9. A method of a communication device, comprising: Transmit first information indicating a first network in which a first network slice is available; After transmitting the first information, receive second information indicating a second network slice that is available in a second network in which a user equipment (UE) is located, and third information indicating the first network slice that is required by a service or application that is active in the UE and that is not available in the second network. Method.

[0398] Appendix 10. The communication device is a Unified Data Management (UDM). The method according to Appendix 9.

[0399] Appendix 11. A method of a user equipment (UE), comprising: Receive a request to transmit first information indicating a first network slice that is available in a first network in which the UE is located, and second information indicating a second network slice that is required by a service or application that is active in the UE and that is not available in the first network; After receiving the request, transmit the first information and the second information. Method.

[0400] Appendix 12. A method of a communication device, comprising: Transmit a request to send first information indicating a first network slice available in a first network where a User Equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. Receive the first information and the second information after transmitting the request. Method.

[0401] Appendix 13. The communication device is a Unified Data Management (UDM). The method according to Appendix 12.

[0402] Appendix 14. A method of a User Equipment (UE), Transmit first information indicating a first network slice for which the UE requests registration in a first network. Receive second information indicating a second network slice. The second network slice is a network slice subscribed to by the UE, different from the first network slice, and available in a second network. Method.

[0403] Appendix 15. Further, perform registration for the second network slice in the second network. The method according to Appendix 14.

[0404] Appendix 16. The second information is included in information indicating a UE route selection policy. The method according to Appendix 14 or 15.

[0405] Appendix 17. A method of a communication device, Receive first information indicating a first network slice for which a user equipment (UE) requests registration in a first network, Transmit second information indicating a second network slice, wherein the second network slice is a network slice subscribed to by the UE, different from the first network slice, and available in a second network, Method.

[0406] Appendix 18. The second information is included in information indicating a UE route selection policy, The method according to Appendix 17.

[0407] Appendix 19. The communication device is a Unified Data Management (UDM), The method according to Appendix 17 or 18.

[0408] Appendix 20. A user equipment (UE), means for transmitting first information indicating a first network slice available in a first network where the UE is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network; means for receiving third information indicating a second network in which the second network slice is available; UE comprising.

[0409] Appendix 21. Further comprising means for performing a registration procedure for the second network, The UE according to Appendix 20.

[0410] Appendix 22. The first information is included in a registration request message, The second information is included in a registration approval message, The UE according to Appendix 20 or 21.

[0411] Appendix 23. The first information and the second information are encrypted. The UE according to any one of Appendices 20 to 22.

[0412] Appendix 24. Means for receiving first information indicating a first network slice available in a first network where a user equipment (UE) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network. Means for transmitting third information indicating a second network in which the second network slice is available. A communication device comprising the above.

[0413] Appendix 25. The communication device further comprises means for storing the first information and the second information. The communication device according to Appendix 24.

[0414] Appendix 26. The communication device is a Unified Data Management (UDM). The communication device according to Appendix 24 or 25.

[0415] Appendix 27. A user equipment (UE), Means for receiving first information indicating a first network in which a first network slice is available. Means for transmitting, after receiving the first information, second information indicating a second network slice available in a second network where the UE is located and third information indicating the first network slice required by a service or application activated in the UE and not available in the second network. A UE comprising the above.

[0416] Transmit first information indicating a first network in which a first network slice is available, after transmitting the first information, receive second information indicating a second network slice available in a second network where a user equipment (UE) is located, and third information indicating the first network slice that is required by a service or application activated in the UE and is not available in the second network. Communication device.

[0417] Appendix 29. The communication device is a Unified Data Management (UDM). The communication device according to Appendix 28.

[0418] Appendix 30. A user equipment (UE), comprising: means for receiving a request to transmit first information indicating a first network slice available in a first network where the UE is located, and second information indicating a second network slice that is required by a service or application activated in the UE and is not available in the first network; means for transmitting the first information and the second information after receiving the request. UE.

[0419] Appendix 31. A communication device, comprising: means for transmitting a request to transmit first information indicating a first network slice available in a first network where a user equipment (UE) is located, and second information indicating a second network slice that is required by a service or application activated in the UE and is not available in the first network; means for receiving the first information and the second information after transmitting the request.

[0420] Appendix 32. The communication device is Unified Data Management (UDM). The communication device according to Appendix 31.

[0421] Appendix 33. A User Equipment (UE), means for transmitting first information indicating a first network slice for which the UE requests registration in a first network; means for receiving second information indicating a second network slice; comprising wherein the second network slice is a network slice subscribed to by the UE, different from the first network slice, and is available in a second network. UE

[0422] Appendix 34. Further comprising means for performing registration for the second network slice in the second network. The UE according to Appendix 33.

[0423] Appendix 35. The second information is included in information indicating a UE route selection policy. The UE according to Appendix 33 or 34.

[0424] Appendix 36. Means for receiving first information indicating a first network slice for which a User Equipment (UE) requests registration in a first network; means for transmitting second information indicating a second network slice; comprising, wherein the second network slice is a network slice subscribed to by the UE, different from the first network slice, and is available in a second network. Communication device.

[0425] Appendix 37. The second information is included in the information indicating the UE route selection policy. The communication device according to Appendix 36.

[0426] Appendix 38. The communication device is a Unified Data Management (UDM). The communication device according to Appendix 36 or 37.

[0427] As described above, the present invention has been described with reference to the embodiments (and examples), but the present invention is not limited to the above embodiments (and examples). Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0428] This application claims priority based on Indian Provisional Patent Application No. 202111057371 filed on December 9, 2021, and incorporates all of its disclosures herein.

Explanation of Reference Numerals

[0429] 1 Telecommunication system 3 UE 5 (R)AN node 7 Core network 20 Data network 31 Transceiver circuit 32 Antenna 33 Controller 34 User interface 35 USIM 36 Memory 51 Transceiver circuit 52 Antenna 53 Network interface 54 Controller 55 Memory 60 RU 61 DU 62 CU 70 AMF 71 SMF 72 UPF 73 PCF 74 AUSF 75 UDM 76 NWDAF 361 Operating System 362 Communication Control Module 501 Cell 502 Cell 551 Operating System 552 Communication Control Module 601 Transceiver Circuit 602 Antenna 603 Network Interface 604 Controller 605 Memory 611 Transceiver Circuit 612 Network Interface 613 Controller 614 Memory 621 Transceiver Circuit 622 Network Interface 623 Controller 624 Memory 701 Transceiver Circuit 702 Network Interface 703 Controller 704 Memory 731 Transceiver Circuit 732 Network Interface 733 Controller 734 Memory 741 Transceiver Circuit 742 Network Interface 743 Controller 744 Memory 751 Transceiver Circuit 752 Network Interface 753 Controller 754 Memory 3621 Transceiver Control Module 5521 Transceiver Control Module 6051 Operating System 6052 Communication Control Module 6141 Operating System 6142 Communication Control Module 6241 Operating System 6242 Communication Control Module 7001 AMF 7002 AMF 7041 Operating System 7042 Communication Control Module 7341 Operating System 7342 Communication Control Module 7441 Operating System 7442 Communication Control Module 7301 PCF 7302 PCF 7541 Operating System 7542 Communication Control Module 60521 Transceiver Control Module 61421 Transceiver Control Module 62421 Transceiver Control Module 70421 Transceiver Control Module 73421 Transceiver Control Module 74421 Transceiver Control Module 75421 Transceiver Control Module< / udm> < / ausf> < / pcf> < / amf>

Claims

Means for transmitting first information indicating a first network slice available in a first network where a UE (User Equipment) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network; Means for receiving third information indicating a second network in which the second network slice is available; A UE comprising the above.

2. The UE according to claim 1, further comprising means for performing a registration procedure for the second network. The UE according to claim 1.

3. The first information is included in a registration request message; The second information is included in a registration approval message; The UE according to claim 1 or 2.

4. The first information and the second information are encrypted; The UE according to any one of claims 1 to 3. Means for receiving first information indicating a first network slice available in a first network where a UE (User equipment) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network; Means for transmitting third information indicating a second network in which the second network slice is available; A communication device comprising the above.

6. The communication device according to claim 5, further comprising means for storing the first information and the second information. The communication device according to claim 5.

7. The communication device is an Integrated Data Management (UDM); The communication device according to claim 5 or 6. A method of a UE, comprising transmitting first information indicating a first network slice available in a first network where a UE (User Equipment) is located, and second information indicating a second network slice required by a service or application activated in the UE and not available in the first network, and receiving third information indicating a second network in which the second network slice is available. Receiving third information indicating a second network in which the second network slice is available. A method of a UE.

9. Receiving first information indicating a first network slice that is available in a first network where a UE (User Equipment) is located, and second information indicating a second network slice that is required by a service or application activated in the UE and is not available in the first network, Transmitting third information indicating a second network in which the second network slice is available. A method for a communication device.

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