Method of a first communication device and the first communication device

Abstract

In the current 3GPP specifications, there are some unclear situations regarding the NSSAA procedure. Aspects of the present disclosure include a method for a first communication device. The method includes communicating with a second communication device. The method includes transmitting, by the first communication device, a Requested Network Slice Selection Assistance Information (NSSAI) to the second communication device when the first communication device has a Pending NSSAI. The Requested NSSAI includes the Pending NSSAI.

Description

Technical Field

[0001] The present disclosure relates to a method for a first communication device, a method for a communication device, a first communication device, and a communication device.

Background Art

[0002] Network Slice-Specific Authentication and Authorization (NSSAA) procedures were introduced in 3GPP specification(s) Release 16.

[0003] According to 3GPP TS 23.501 [2], the serving Public Land Mobile Network (PLMN) needs to perform NSSAA for the single Network Slice Selection Assistance Information (S-NSSAI) of its target Home Public Land Mobile Network (HPLMN) based on subscription information.

[0004] According to 3GPP TS 24.501 [5], the 3GPP specification further defines a mechanism by which a registration procedure is initiated by a User Equipment (UE) while the NSSAA procedure is in progress. In this case, the UE does not include the S-NSSAI(s) managed as Pending NSSAI in the UE in the Requested NSSAI according to 3GPP TS 24.501 [5].

Summary of the Invention

Problems to be Solved by the Invention

[0005] There are some unclear situations regarding the NSSAA procedure in the current 3GPP specifications.

[0006] For example, according to 3GPP TS 23.502 [3], when the Access and Mobility Management Function (AMF) receives a Registration Request message from a UE including the Requested NSSAI, the AMF can send an Nnssf_NSSelection_Get message including the received Requested NSSAI to the Network Slice Selection Function (NSSF). When receiving the Nnssf_NSSelection_Get message from the AMF, the NSSF provides a list of AMF sets or candidate AMFs (plural available) together with the Allowed NSSAI. The list of AMF sets or candidate AMFs (plural available) and the Allowed NSSAI are selected by the NSSF based on the Requested NSSAI received from the AMF as input information. Then, the AMF can execute registration by means of an AMF reallocation procedure for changing the AMF according to Section 4.2.2.2.3 of 3GPP TS 23.502 [3].

[0007] Also, for example, as described above, the 3GPP specification defines a mechanism by which the UE starts a registration procedure while the NSSAA procedure is in progress. In this case, the UE does not include the S-NSSAI(s) that are regarded as Pending NSSAI in the UE in the Requested NSSAI according to 3GPP TS 24.501 [5].

[0008] For example, if the AMF executes a query to the NSSF to discover or select a list of AMF sets or candidate AMFs (plural available) during the registration procedure while the NSSAA procedure is in progress, the Requested NSSAI as input information to the NSSF does not include the S-NSSAI(s) in the Pending NSSAI.

[0009] However, for example, the S-NSSAI(s) within the Pending NSSAI can become part of the permitted NSSAI when the NSSAA procedure is successfully completed.

[0010] In this case, it may happen that the newly selected AMF by the AMF reallocation procedure cannot serve the S-NSSAI(s) newly added to the permitted NSSAI after the completion of the NSSAA procedure, because those S-NSSAI(s) are not considered by the NSSF regarding the discovery or selection of the AMF set or the list of candidate AMF(s).

[0011] As a result, after the NSSAA procedure, all services that use the S-NSSAI(s) newly added to the permitted NSSAI may not be provided to the UE because the newly selected AMF cannot process or support the S-NSSAI(s).

[0012] This may cause a significant service degradation in all services that use network slices in a 5G system (5G System: 5GS).

Means for Solving the Problem

[0013] Aspects of the present disclosure include a method for a first communication device. The method includes communicating with a second communication device. The method includes transmitting a Requested NSSAI to the second communication device when the first communication device has Pending Network Slice Selection Assistance Information (NSSAI). The Requested NSSAI includes the Pending NSSAI. Aspects of the present disclosure include a method for a first communication device. The method includes communicating with a second communication device. The method includes receiving, from the second communication device, a Requested NSSAI if Pending Network Slice Selection Assistance Information (NSSAI) is stored in the second communication device. The Requested NSSAI includes the Pending NSSAI. Aspects of the present disclosure include a method for a first communication device. The method includes communicating with a second communication device. The method includes transmitting, to the second communication device, a Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI). The S-NSSAI is used in procedures related to reallocation of an Access and Mobility Management Function (AMF). Aspects of the present disclosure include a method for a communication device. The method includes receiving a Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI). The method includes transmitting the S-NSSAI. The S-NSSAI is used in procedures related to reallocation of an Access and Mobility Management Function (AMF). One aspect of the present disclosure includes a first communication device. The first communication device includes means for communicating with a second communication device. The first communication device includes means for transmitting a Requested Network Slice Selection Assistance Information (NSSAI) to the second communication device when the first communication device has a Pending Network Slice Selection Assistance Information (NSSAI). The Requested NSSAI includes the Pending NSSAI. One aspect of the present disclosure includes a first communication device. The first communication device includes means for communicating with a second communication device. The first communication device includes means for receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communication device, and the Pending NSSAI is stored in the second communication device. The Requested NSSAI includes the Pending NSSAI. One aspect of the present disclosure includes a first communication device. The first communication device includes means for communicating with a second communication device. The first communication device includes means for transmitting a Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device. The S-NSSAI is used in procedures related to reallocation of an Access and Mobility Management Function (AMF). One aspect of the present disclosure includes a communication device. The communication device includes means for receiving a single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (NSSAI). The communication device includes means for transmitting the S-NSSAI. The S-NSSAI is used in procedures related to the reallocation of an access and mobility management function (AMF).

Brief Description of the Drawings

[0014]

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DETAILED DESCRIPTION OF THE INVENTION

[0015] Abbreviations For the purposes of this document, 3GPP TR 21.905 [1] and the following abbreviations apply. Abbreviations defined in this document take precedence over the definitions in 3GPP TR 21.905 [1] if the same abbreviations exist. 4G-GUTI 4G Globally Unique Temporary UE Identity (4G globally unique temporary UE identification information) 5GC 5G Core Network (5G core network) 5GLAN 5G Local Area Network (5G local area network) 5GS 5G System (5G system) 5G-AN 5G Access Network (5G access network) 5G-AN PDB 5G Access Network Packet Delay Budget (5G access network packet delay budget) 5G-EIR 5G-Equipment Identity Register (5G equipment identity register) 5G-GUTI 5G Globally Unique Temporary Identifier (5G global unique temporary identifier) 5G-BRG 5G Broadband Residential Gateway (5G broadband residential gateway) 5G-CRG 5G Cable Residential Gateway (5G cable residential gateway) 5G GM 5G Grand Master (5G grand master) 5G-RG 5G Residential Gateway(5G Residential Gateway) 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier(5G S-Temporary Mobile Subscription Identifier) 5G VN 5G Virtual Network(5G Virtual Network) 5QI 5G QoS Identifier(5G QoS Identifier) AF Application Function(Application Function) AMF Access and Mobility Management Function(Access and Mobility Management Function) AMF-G Geographically selected Access and Mobility Management Function(Geographically selected Access and Mobility Management Function) AMF-NG Non-Geographically selected Access and Mobility Management Function(Non-Geographically selected Access and Mobility Management Function) ANDSF Access Network Discovery and Selection Function(Access Network Discovery and Selection Function) AS Access Stratum(Access Stratum) ATSSS Access Traffic Steering, Switching, Splitting(Access Traffic Steering, Switching, Splitting) ATSSS-LL ATSSS Low-Layer(ATSSS Low-Layer) AUSF Authentication Server Function(Authentication Server Function) AUTN Authentication token(Authentication token) BCCH Broadcast Control Channel (Broadcast Control Channel) BMCA Best Master Clock Algorithm (Best Master Clock Algorithm) BSF Binding Support Function (Binding Support Function) CAG Closed Access Group (Closed Access Group) CAPIF Common API Framework for 3GPP northbound APIs (Common API Framework for 3GPP Northbound APIs) CHF Charging Function (Charging Function) CN PDB Core Network Packet Delay Budget (Core Network Packet Delay Budget) CP Control Plane (Control Plane) DAPS Dual Active Protocol Stacks (Dual Active Protocol Stacks) DL Downlink (Downlink) DN Data Network (Data Network) DNAI DN Access Identifier (DN Access Identifier) DNN Data Network Name (Data Network Name) DRX Discontinuous Reception (Discontinuous Reception) DS-TT Device-side TSN translator (Device-side TSN Translator) ePDG evolved Packet Data Gateway (Evolved Packet Data Gateway) EBI EPS Bearer Identity (EPS Bearer Identity) EPS Evolved Packet System (Evolved Packet System) EUI Extended Unique Identifier (Extended Unique Identifier) FAR Forwarding Action Rule (Forwarding Action Rule) FN-BRG Fixed Network Broadband RG (Fixed Network Broadband RG) FN-CRG Fixed Network Cable RG (Fixed Network Cable RG) FN-RG Fixed Network RG (Fixed Network RG) FQDN Fully Qualified Domain Name (Fully Qualified Domain Name) GFBR Guaranteed Flow Bit Rate (Guaranteed Flow Bit Rate) GMLC Gateway Mobile Location Centre (Gateway Mobile Location Centre) GPSI Generic Public Subscription Identifier (Generic Public Subscription Identifier) GUAMI Globally Unique AMF Identifier (Globally Unique AMF Identifier) GUTI Globally Unique Temporary UE Identity (Globally Unique Temporary UE Identity) HPLMN Home Public Land Mobile Network (Home Public Land Mobile Network) HR Home Routed (roaming) (Home Routed (roaming)) IAB Integrated access and backhaul (Integrated access and backhaul) IMEI / TAC IMEI Type Allocation Code (IMEI Type Allocation Code) IPUPS Inter PLMN UP Security (Inter PLMN UP Security) I-SMF Intermediate SMF (Intermediate SMF) I-UPF Intermediate UPF (Intermediate UPF) LADN Local Area Data Network (Local Area Data Network) LBO Local Break Out (roaming) (Local Break Out (roaming)) LMF Location Management Function (Location Management Function) LoA Level of Automation (Level of Automation) LPP LTE Positioning Protocol (LTE Positioning Protocol) LRF Location Retrieval Function (Location Retrieval Function) MCC Mobile country code (Mobile country code) MCX Mission Critical Service (Mission Critical Service) MDBV Maximum Data Burst Volume (Maximum Data Burst Volume) MFBR Maximum Flow Bit Rate (Maximum Flow Bit Rate) MICO Mobile Initiated Connection Only (Mobile Initiated Connection Only) MITM Man In the Middle (Man In the Middle) MNC Mobile Network Code (Mobile Network Code) MPS Multimedia Priority Service (Multimedia Priority Service) MPTCP Multi-Path TCP Protocol (Multi-Path TCP Protocol) N3IWF Non-3GPP InterWorking Function (Non-3GPP InterWorking Function) N3GPP Non-3GPP access (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 (Network Slice Simultaneous Registration Group) NW-TT Network-side TSN translator (Network-side TSN Translator) NWDAF Network Data Analytics Function (Network Data Analytics Function) PCF Policy Control Function (Policy Control Function) PCO Protocol Configuration Options (Protocol Configuration Options) PDB Packet Delay Budget (Packet Delay Budget) PDR Packet Detection Rule (Packet Detection Rule) PDU Protocol Data Unit (Protocol Data Unit) PEI Permanent Equipment Identifier (Permanent Equipment Identifier) PER Packet Error Rate (Packet Error Rate) PFD Packet Flow Description (Packet Flow Description) PLMN Public Land Mobile Network (Public Land Mobile Network) PNI-NPN Public Network Integrated Non-Public Network (Public Network Integrated Non-Public Network) PPD Paging Policy Differentiation (Paging Policy Differentiation) PPF Paging Proceed Flag (Paging Proceed Flag) PPI Paging Policy Indicator (Paging Policy Indicator) PSA PDU Session Anchor (PDU Session Anchor) PTP Precision Time Protocol (Precision Time Synchronization Protocol) QFI QoS Flow Identifier (QoS Flow Identification) QoE Quality of Experience (Quality of Experience) RACS Radio Capabilities Signalling Optimisation (Radio Function Signalling Optimization) (R)AN (Radio) Access Network ((Radio) Access Network) RAT Radio Access Technology (Radio Access Technology) RG Residential Gateway (Residential Gateway) RIM Remote Interference Management (Remote Interference Management) RQA Reflective QoS Attribute (Reflective QoS Attribute) RQI Reflective QoS Indication (Reflective QoS Indication) RSN Redundancy Sequence Number (Redundancy Sequence Number) SA NR Standalone New Radio (Standalone New Radio) SBA Service Based Architecture (Service-Based Architecture) SBI Service Based Interface (Service-Based Interface) SCP Service Communication Proxy (Service Communication Proxy) SD Slice Differentiator (Slice Differentiator) SEAF Security Anchor Functionality (Security Anchor Function) SEPP Security Edge Protection Proxy (Security Edge Protection Proxy) SMF Session Management Function (Session Management Function) SMSF Short Message Service Function (Short Message Service Function) SN Sequence Number (Sequence Number) SN Name Serving Network Name (Serving Network Name) SNPN Stand-alone Non-Public Network (Stand-alone Non-Public Network) S-NSSAI Single Network Slice Selection Assistance Information (Single Network Slice Selection Assistance Information) SSC Session and Service Continuity (Session and Service Continuity) SSCMSP Session and Service Continuity Mode Selection Policy (Session and Service Continuity Mode Selection Policy) SST Slice / Service Type (Slice / Service Type) SUCI Subscription Concealed Identifier (Subscription Concealed Identifier) SUPI Subscription Permanent Identifier (Subscription Permanent Identifier) SV Software Version (Software Version) TMSI Temporary Mobile Subscriber Identity (Temporary Mobile Subscriber Identity) TNAN Trusted Non-3GPP Access Network (Trusted Non-3GPP Access Network) TNAP Trusted Non-3GPP Access Point (Trusted Non-3GPP Access Point) TNGF Trusted Non-3GPP Gateway Function (Trusted Non-3GPP Gateway Function) TNL Transport Network Layer (Transport Network Layer) TNLA Transport Network Layer Association (Transport Network Layer Association) TSC Time Sensitive Communication (Time Sensitive Communication) TSCAI TSC Assistance Information (TSC Assistance Information) TSN Time Sensitive Networking (Time Sensitive Networking) TSN GM TSN Grand Master (TSN Grand Master) TSP Traffic Steering Policy (Traffic Steering Policy) TT TSN Translator (TSN Translator) TWIF Trusted WLAN Interworking Function (Trusted WLAN Interworking Function) UCMF UE radio Capability Management Function (UE Radio Capability Management Function) UDM Unified Data Management (Unified Data Management) UDR Unified Data Repository (Unified Data Repository) UDSF Unstructured Data Storage Function (Unstructured Data Storage Function) UE User Equipment (User Equipment) UL Uplink (Uplink) UL CL Uplink Classifier (Uplink Classifier) UPF User Plane Function (User Plane Function) UPSI UE Policy Section Identifier (UE Policy Section Identifier) URLLC Ultra Reliable Low Latency Communication (Ultra Reliable and Low Latency Communication) URRP-AMF UE Reachability Request Parameter for AMF (UE Reachability Request Parameter for AMF) URSP UE Route Selection Policy (UE Route Selection Policy) VID VLAN Identifier (VLAN Identifier) VLAN Virtual Local Area Network (Virtual Local Area Network) VPLMN Visited Public Land Mobile Network (Visited Public Land Mobile Network) W-5GAN Wireline 5G Access Network (Wireline 5G Access Network) W-5GBAN Wireline BBF Access Network (Wireline BBF Access Network) W-5GCAN Wireline 5G Cable Access Network (Wireline 5G Cable Access Network) W-AGF Wireline Access Gateway Function (Wireline Access Gateway Function)

[0016] Definition For the purposes of this document, the terms and definitions in 3GPP TR 21.905 [1] and those described below apply. Terms defined in this document take precedence over those with the same definition in 3GPP TR 21.905 [1] if applicable.

Prior Art Documents

Non-Patent Documents

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Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

[0018] Generally Those skilled in the art will understand that the elements of the drawings are shown for simplicity and may not necessarily be drawn to scale. Further, with respect to the settings of the device, one or more components of the device may be represented in the drawings by conventional symbols, and the drawings can only show the specific details relevant to the understanding of the aspects of the present disclosure so as not to obscure the drawings with details that will be readily apparent to those skilled in the art who benefit from the description herein.

[0019] For the purpose of promoting an understanding of the principles of the present disclosure, reference is made to the embodiments shown in the figures and specific language is used to describe them. Nevertheless, it will be understood that no limitation of the scope of the present disclosure is thereby intended. Such changes and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as would normally occur to one of ordinary skill in the art, are to be construed as being within the scope of the present disclosure.

[0020] The terms "comprising", "comprises" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or entities or subsystems or elements or structures or components preceded by "comprising" do not, without further limitation, preclude the existence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures or additional components. Throughout this specification, the appearances of the phrases "in an embodiment", "in another embodiment" and similar language are not necessarily all referring to the same embodiment, although they may.

[0021] 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.

[0022] In the following specification and claims, reference is made to several terms that may be defined as having the following meanings. The singular forms ("a", "an") and "the" include plural references unless the context clearly dictates otherwise.

[0023] As used herein, data is meaningful information and represents values resulting from parameters, so information is associated with data and knowledge. Further knowledge means the understanding of abstract or concrete concepts. It should be noted that this exemplary system is simplified to facilitate the description of the disclosed subject matter and is not intended to limit the scope of the present disclosure. In addition to or instead of the system, other devices, systems, and settings can be used to implement the aspects disclosed herein, and all such aspects are considered to be within the scope of the present disclosure.

[0024] Also, each aspect and each element included in the following aspects may be implemented independently or in any combination. These aspects include different novel features. Therefore, these aspects contribute to the achievement of different purposes or the solution of different problems and contribute to the acquisition of different advantages.

[0025] An exemplary object of the present disclosure is to provide a method and an apparatus capable of solving the above problems.

[0026] The following list explains the intended interpretations of the terms used in the present disclosure. - Subscribed S-NSSAI (Subscribed S-NSSAI), Subscribed S-NSSAIs (Subscribed S-NSSAIs), or Subscribed S-NSSAI(s) (Subscribed S-NSSAI(s)): This can be equal to a list of S-NSSAIs (plural) within the Subscribed NSSAI or an S-NSSAI (plural) within the Subscribed NSSAI. - Allowed S-NSSAI, Allowed S-NSSAIs, or Allowed S-NSSAI(s): This can be equal to a list of S-NSSAI(s) within the Allowed NSSAI or S-NSSAI(s) within the Allowed NSSAI. - Configured S-NSSAI, Configured S-NSSAIs, or Configured S-NSSAI(s): This can be equal to a list of S-NSSAI(s) within the Configured NSSAI or S-NSSAI(s) within the Configured NSSAI. - Rejected S-NSSAI, Rejected S-NSSAIs, or Rejected S-NSSAI(s): This can be equal to a list of S-NSSAI(s) within the Rejected NSSAI or S-NSSAI(s) within the Rejected NSSAI. - Pending S-NSSAI, Pending S-NSSAIs, or Pending S-NSSAI(s): This can be equal to a list of S-NSSAI(s) within the Pending NSSAI or S-NSSAI(s) within the Pending NSSAI.

[0027] In the following aspects, the NSSAA can be expressed as an NSSAA procedure.

[0028] The method of a first communication device according to an exemplary aspect of the present disclosure includes communicating with a second communication device. The method includes transmitting, to the second communication device, a single network slice selection assistance information (S-NSSAI) included in a pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI) for procedures related to reallocation of an access and mobility management function (AMF).

[0029] The method of a communication device according to an exemplary aspect of the present disclosure includes receiving a single network slice selection assistance information (S-NSSAI) of a pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI). The method includes determining, based on the S-NSSAI, a set of access and mobility management functions (Access and Mobility Management Function: AMF) or a list of AMF addresses. The method includes transmitting the set of AMF or the list of AMF addresses.

[0030] The method of a first communication device according to an exemplary aspect of the present disclosure includes communicating with a second communication device. The method includes transmitting, to the second communication device, a single network slice selection assistance information (S-NSSAI) included in a pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI).

[0031] A method of a communication device according to an exemplary aspect of the present disclosure includes receiving a single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI). The method includes transmitting the S-NSSAI. The S-NSSAI is used in procedures related to the reallocation of an access and mobility management function (AMF).

[0032] A first communication device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to communicate with a second communication device. The at least one hardware processor is configured to transmit to the second communication device a single network slice selection assistance information (S-NSSAI) included in pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI) for procedures related to the reallocation of an access and mobility management function (AMF).

[0033] A communication device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI). The at least one hardware processor is configured to determine a set of access and mobility management functions (AMF) or a list of AMF addresses based on the S-NSSAI. The at least one hardware processor is configured to transmit the set of AMF or the list of AMF addresses.

[0034] A first communication device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to communicate with a second communication device. The at least one hardware processor is configured to transmit to the second communication device a single network slice selection assistance information (S-NSSAI) included in pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI). The S-NSSAI is used in procedures related to reallocation of access and mobility management functions (AMF).

[0035] A communication device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI). The at least one hardware processor is configured to transmit the S-NSSAI. The S-NSSAI is used in procedures related to reallocation of an access and mobility management function (AMF).

[0036] First aspect When a UE requests access to an S-NSSAI (s), for example, when the UE sends a registration request message including a Requested NSSAI that includes the S-NSSAI (s), the serving PLMN performs NSSAA on the S-NSSAI (s) of the HPLMN that is the subject of NSSAA based on the subscription information. When the UE sends a registration request message including the S-NSSAI (s) within the Requested NSSAI that is the subject of NSSAA, the AMF sends a Registration Accept message including the S-NSSAI (s) to the list of Pending NSSAI (for example, the AMF sends a registration acceptance message including the Pending NSSAI including the S-NSSAI (s)). After the completion of the registration procedure (for example, after the sending of the registration acceptance message), the AMF starts the NSSAA procedure for the S-NSSAI (s) within the Pending NSSAI. If the NSSAA procedure is successful, the AMF notifies the UE that the S-NSSAI within the Pending NSSAI is currently available, causes the UE to delete the S-NSSAI (s) from the storage of the Pending NSSAI within the UE, and causes them to be placed in the storage of the Allowed NSSAI within the UE.

[0037] The NSSAA procedure enables the execution of authentication and authorization specific to the use of a network slice using an AAA server located in an external network.

[0038] According to 3GPP TS 23.502 [3], when the AMF receives a registration request message containing the Requested NSSAI from the UE, the AMF sends an Nnssf_NSSelection_Get message containing the received Requested NSSAI to the NSSF in order to discover the appropriate AMF(s) that can support the network slices within the Requested NSSAI as much as possible. When the NSSF receives the Nnssf_NSSelection_Get message from the AMF, the NSSF provides a list of AMF sets or candidate AMF(s) used to serve the UE together with the Allowed NSSAI. The list of AMF sets or candidate AMF(s) and the Allowed NSSAI are selected by the NSSF based on the Requested NSSAI received from the AMF as input information. Then, the AMF can execute the registration by means of the AMF reallocation procedure to change the AMF according to section 4.2.2.2.3 of 3GPP TS 23.502 [3].

[0039] During the progress of the NSSAA procedure, if the AMF70 executes a query to discover the appropriate AMF from the NSSF76 during the registration procedure (for example, to select or determine a list of AMF sets or candidate AMF(s)), the Requested NSSAI as input information to the NSSF does not include the S-NSSAI(s) within the Pending NSSAI.

[0040] However, if the NSSAA procedure is successfully completed, the S-NSSAI(s) within the Pending NSSAI can be added to the Allowed NSSAI.

[0041] In this case, since the S-NSSAI(s) within the Pending NSSAI can be added to the Allowed NSSAI when the NSSAA procedure is successfully completed, the S-NSSAI(s) within the Pending NSSAI need to be considered by the NSSF76 to discover the appropriate AMF. The first aspect is to solve the above problems.

[0042] First example of the first aspect: The first example of the first aspect discloses a method in which the AMF 70 sends an Nnssf_NSSelection_Get message including the Pending NSSAI in addition to the Requested NSSAI to the NSSF 76 in order to discover an AMF suitable for serving the UE 3.

[0043] Hereinafter, with reference to FIG. 1, the detailed processing of the first example of the first aspect will be described.

[0044] Step 0. As defined in section 4.2.9.2 of 3GPP TS 23.502 [3], the Network Slice-Specific Authentication and Authorization (NSSAA) procedure is in progress by the UE 3.

[0045] For example, the UE 3 and the AMF 70 may have a Pending NSSAI while the NSSAA procedure is in progress.

[0046] For example, the UE 3 can execute a first registration procedure by sending a first registration request message. The first registration request message may include a first Requested NSSAI. The first Requested NSSAI may include S-NSSAI1.

[0047] If S-NSSAI 1 is subject to the NSSAA procedure, a first NSSAA procedure for S-NSSAI 1 may be executed and in progress at step 0.

[0048] When the first NSSAA procedure for S-NSSAI1 is in progress, the UE 3 and the AMF 70 can have a Pending NSSAI including S-NSSAI1.

[0049] The UE 3 may be in the CM-CONNECTED state.

[0050] While the NSSAA procedure of is in progress, UE3 sends a registration request message to AMF70, and steps 1 to 3c are performed as described in the registration procedure by AMF reallocation in section 4.2.2.2.3 of 3GPP TS 23.502 [3]. For example, some of steps 1 to 3c may be performed.

[0051] For example, while the first NSSAA procedure of the above-mentioned S-NSSAI1 is in progress, UE3 can execute a second registration procedure by sending a second registration request message including a second Requested NSSAI in step 1. The second Requested NSSAI may include S-NSSAI2.

[0052] If AMF70 decides that it is necessary to re-route the second registration request message to another AMF (for example, when AMF70 is not the appropriate AMF to serve UE3), AMF70 can execute the registration procedure by AMF reallocation in step 1 (that is, steps 1 to 3c may be performed as described in the registration procedure by AMF reallocation).

[0053] The registration procedure by AMF reallocation may be expressed as a procedure regarding the reallocation of the AMF.

[0054] Step 2. AMF70 sends an Nnssf_NSSelection_Get message including Requested NSSAI and Pending NSSAI to NSSF76. The Requested NSSAI is taken in by AMF70 by copying it from the registration request message received from UE3 in step 1. When the NSSAA procedure is in progress for an S-NSSAI, that is, when AMF70 manages such S-NSSAI(s) as Pending NSSAI, the Pending NSSAI is taken in by AMF70.

[0055] For example, when UE3 sends a second registration request message including a second Requested NSSAI that includes S-NSSAI2 in step 1, AMF70 can include the second Requested NSSAI that includes S-NSSAI2 in the Nnssf_NSSelection_Get message in step 2.

[0056] For example, the first NSSAA procedure for S-NSSAI1 as described above is in progress at step 0, and AMF70 can manage (or have) a Pending NSSAI that includes S-NSSAI1. In this case, AMF70 can include the Pending NSSAI that includes S-NSSAI1 at step 2 in the Nnssf_NSSelection_Get message.

[0057] For example, AMF70 can send at least one of the S-NSSAI(s) included in the Requested NSSAI and the S-NSSAI(s) included in the Pending NSSAI(s).

[0058] At least one of the S-NSSAI(s) included in the Requested NSSAI and the S-NSSAI(s) included in the Pending NSSAI may be included in the Nnssf_NSSelection_Get message.

[0059] AMF70 can send the Nnssf_NSSelection_Get message for the registration procedure due to AMF reallocation.

[0060] For example, the Nnssf_NSSelection_Get message can include a Pending NSSAI that includes any Pending S-NSSAI(s) (e.g., the S-NSSAI(s) included in the Pending NSSAI) stored in AMF70.

[0061] For example, the Nnssf_NSSelection_Get message may include a Pending NSSAI that includes the S-NSSAI(s) included in the Requested NSSAI(s) of the registration request message received from the UE3.

[0062] The S-NSSAI(s) included in the Pending NSSAI of the Nnssf_NSSelection_Get message may be subject to the NSSAA procedure.

[0063] For example, the Nnssf_NSSelection_Get message may include a mapping of the Pending NSSAI. For example, the Nnssf_NSSelection_Get message may include a mapping of the Pending NSSAI included in the Nnssf_NSSelection_Get message.

[0064] Step 3. The NSSF76 sends an Nnssf_NSSelection_Get response message including at least one of a set of AMFs, a list of AMF addresses, and a list of candidate AMF(s) to the AMF70. The Nnssf_NSSelection_Get response message may include a permitted NSSAI. The NSSF76 considers the received Requested NSSAI and the received Pending NSSAI to discover or determine a set of AMFs or a list of AMF addresses or a list of candidate AMF(s).

[0065] For example, the NSSF76 may discover or determine the AMF(s) that can process the S-NSSAI(s) in the Requested NSSAI and the Pending NSSAI.

[0066] For example, if the Nnssf_NSSelection_Get message includes a Requested NSSAI including S-NSSAI2 and a Pending NSSAI including S-NSSAI1, the NSSF76 can discover or determine an AMF (s) capable of processing S-NSSAI1 and S-NSSAI2.

[0067] For example, if the Nnssf_NSSelection_Get message includes a Requested NSSAI including S-NSSAI2 and a Pending NSSAI including S-NSSAI1, the NSSF76 can discover or determine an AMF (s) capable of processing S-NSSAI1 and S-NSSAI2, and include the AMF (s) in a set of AMFs or a list of candidate AMF (s).

[0068] For example, if the Nnssf_NSSelection_Get message includes a Requested NSSAI including S-NSSAI2 and a Pending NSSAI including S-NSSAI1, the NSSF76 can discover an AMF (s) capable of processing S-NSSAI1 and S-NSSAI2, discover (or determine) the address of the AMF (s), and include the address in a list of addresses of the AMF (s).

[0069] For example, the Nnssf_NSSelection_Get response message may include a mapping of the Pending NSSAI. For example, the Nnssf_NSSelection_Get response message may include a mapping of the Pending NSSAI included in the Nnssf_NSSelection_Get response message.

[0070] Step 4. Steps 5 to 8 are performed as described in the registration by AMF reallocation in section 4.2.2.2.3 of 3GPP TS 23.502 [3]. For example, some of steps 5 to 8 may be performed.

[0071] For example, if the Pending NSSAI is not provided, or if the Pending NSSAI includes one or more S-NSSAIs that are not valid in the serving PLMN, based on the subscribed S-NSSAI(s) and operator settings, the NSSF 76 can also determine the configured NSSAI for the serving PLMN and, if applicable, the related mapping of the configured NSSAI to the HPLMN S-NSSAI(s), and thus these may be configured in the UE 3.

[0072] For example, if one or more S-NSSAIs within the Pending NSSAI are not supported in the TA or are not available in the Public Land Mobile Network (PLMN), the NSSF 76 can include the S-NSSAI(s) in the rejected NSSAI, together with the reason indicating that the S-NSSAI(s) are not supported in the TA or not supported in the PLMN. The NSSF 76 can send at least one of the rejected NSSAI and the reason to the AMF 70 via a message (e.g., the Nnssf_NSSelection_Get response message). When the AMF 70 receives a message including the rejected NSSAI, the AMF 70 can send at least one of the rejected NSSAI and the reason to the UE 3.

[0073] For example, if the Pending S-NSSAI(s) are rejected by the NSSF 76 (e.g., when the AMF 70 receives at least one of the rejected NSSAI and the reason), the AMF 70 can abort the ongoing NSSAA procedure.

[0074] For example, when the first NSSAA procedure for S-NSSAI1 as described above is in progress at step 0, and the AMF 70 includes the Pending NSSAI including S-NSSAI1 in the Nnssf_NSSelection_Get message, and the AMF 70 receives a rejected NSSAI including S-NSSAI1 from the NSSF 76, the AMF 70 can abort the first NSSAA procedure.

[0075] According to the first example of the first aspect, the AMF 70 includes, for example, the Pending NSSAI in the Nnssf_NSSelection_Get message. The NSSF 76 takes the Pending NSSAI into account to discover a list of AMF sets or AMF addresses.

[0076] According to the first example of the first aspect, the above problems can be solved. For example, in the first example of the first aspect, after the NSSAA procedure, all services (plural) that use the newly added S-NSSAI(s) in the permitted NSSAI may not be provided to the UE because the newly selected AMF cannot process or support the S-NSSAI(s). For example, the first example of the first aspect can solve problems such as significant service degradation of all services (plural) that use network slices in 5GS.

[0077] Variant 1 of the first example of the first aspect: In step 2, instead of adding the Pending NSSAI to the Nnssf_NSSelection_Get message, the AMF 70 can add the S-NSSAI(s) within the Pending NSSAI to the Requested NSSAI. As a result, the Requested NSSAI in the Nnssf_NSSelection_Get message can include the S-NSSAI(s) received from the UE3 within the Requested NSSAI in the registration request message of step 1 and the S-NSSAI(s) from the Pending NSSAI in the AMF 70.

[0078] For example, when the AMF 70 has a Pending NSSAI that includes S-NSSAI1, the AMF 70 can include S-NSSAI1 in the Requested NSSAI within the Nnssf_NSSelection_Get message. In this case, the AMF 70 may not include the Pending NSSAI in the Nnssf_NSSelection_Get message.

[0079] When receiving the Nnssf_NSSelection_Get message at the NSSF 76, the NSSF 76 can find a list of AMF sets or AMF addresses based on the received Requested NSSAI.

[0080] Modification Example 2 of the First Example of the First Aspect: In step 3, the NSSF 76 can construct a permitted NSSAI taking into account the received Pending NSSAI and the received Requested NSSAI. Since the S-NSSAI(s) within the Pending NSSAI cannot be part of the permitted NSSAI, if the S-NSSAI(s) is / are received from the AMF 70 as part of the Pending NSSAI, the NSSF 76 can extract the S-NSSAI(s) from the permitted NSSAI.

[0081] For example, the NSSF 76 may not include the S-NSSAI(s) included in the Pending NSSAI in the permitted NSSAI.

[0082] For example, the NSSF 76 can determine the permitted NSSAI (e.g., the content of the permitted NSSAI) based on at least one of the Pending NSSAI (e.g., the S-NSSAI(s) within the Pending NSSAI) and the Requested NSSAI (e.g., the S-NSSAI(s) within the Requested NSSAI).

[0083] For example, when S-NSSAI A is included in the Pending NSSAI and S-NSSAI A and S-NSSAI B are included in the Requested NSSAI, the NSSF76 can construct a permitted NSSAI that includes S-NSSAI B.

[0084] The second example of the first aspect can apply Variation 2 of the first example of the first aspect.

[0085] Variation 3 of the first example of Aspect 1: When receiving the Nnssf_NSSelection_Get response message in step 3, in step 4, when the AMF70 notifies the UE3 of the permitted NSSAI by setting the permitted NSSAI in the registration acceptance message, the AMF70 can construct the permitted NSSAI taking into account the Pending NSSAI within the AMF70 and the permitted NSSAI received from the NSSF76. Since the S-NSSAI(s) within the Pending NSSAI cannot be part of the permitted NSSAI, if the S-NSSAI(s) is / are within the Pending NSSAI in the AMF70, the AMF70 can extract the S-NSSAI(s) from the permitted NSSAI received from the NSSF76.

[0086] For example, the AMF70 may not include the S-NSSAI(s) included in the Pending NSSAI of the AMF70 in the permitted NSSAI within the registration acceptance message.

[0087] For example, the AMF70 can determine the permitted NSSAI (e.g., the content of the permitted NSSAI) based on at least one of the Pending NSSAI (e.g., the S-NSSAI(s) within the Pending NSSAI) and the permitted NSSAI received from the NSSF76 (e.g., the S-NSSAI(s) within the received permitted NSSAI).

[0088] For example, if S-NSSAI C is included in the Pending NSSAI of AMF 70 and S-NSSAI C and S-NSSAI D are included in the permitted NSSAI received from NSSF 76, AMF 70 can construct a permitted NSSAI including S-NSSAI D. Then, AMF 70 can send a registration acceptance message including the permitted NSSAI including S-NSSAI D.

[0089] The registration acceptance message may be another NAS message.

[0090] For the second example of the first aspect, Modification Example 3 of the first example of the first aspect can be applied.

[0091] Modification Example 4 of the first example of the first aspect: The network operator can have a setting or policy regarding whether a network slice(s) (or S-NSSAI(s)) from the Pending NSSAI needs to be used by NSSF 76 for AMF reallocation while the NSSAA procedure is still being executed (or in progress).

[0092] For example, in step 2 of FIG. 1, when determining whether to include a network slice(s) (or S-NSSAI(s)) from the Pending NSSAI in the Nnssf_NSSelection_Get message to NSSF 76, AMF 70 can use the setting or policy of the network operator within AMF 70.

[0093] For example, in step 2 of FIG. 1, AMF 70 can determine whether to include the Pending NSSAI (e.g., S-NSSAI(s) within the Pending NSSAI) in the Nnssf_NSSelection_Get message based on the setting or policy of the network operator within AMF 70.

[0094] For example, in step 2 of FIG. 1, AMF70 can use the settings or policies of the network operator within AMF70 to determine which network slice(s) (or S-NSSAI(s)) of the Pending NSSAI need to be included in the Nnssf_NSSelection_Get message to NSSF76.

[0095] Modification example 5 of the first example of the first aspect: In one example, when UE3 is registered with AMF70 via another access, AMF70 sends two Pending NSSAIs, i.e., the Pending NSSAI for each access type, to NSSF76. The Pending NSSAI for a certain access type is the subject of NSSAA and includes the S-NSSAI(s) requested via that access type. When NSSF76 receives the separate Pending NSSAIs for each access type, NSSF76 determines the permitted NSSAI on each access type taking both Pending NSSAIs into account. NSSF76 can also determine which AMF can process the permitted NSSAI, Pending NSSAI for each access type. NSSF76 sends an Nnssf_NSSelection_Get response message including at least one of a list of AMF sets or AMF addresses, the permitted NSSAI for one access type, the mapping of the permitted NSSAI, the permitted NSSAI for another access type, the mapping of the permitted NSSAI, NSI ID(s), NRF(s), a list of rejections (S-NSSAI(s), cause value(s)), the configured NSSAI of the serving PLMN, the mapping of the configured NSSAI, the Pending NSSAI for one access, the Pending NSSAI for another access, the mapping of the Pending NSSAI for one access, and the mapping of the Pending NSSAI for another access.

[0096] If the S-NSSAI(s) within the Pending NSSAI of any access is / are not supported in the AMF set or list of AMF sets selected by the NSSF 76, the NSSF 76 shall move the S-NSSAI(s) from the Pending NSSAI, along with the reason for its rejection, into the reject NSSAI for that access (e.g., at least one of any accesses). The reason may indicate, for example, that the Pending NSSAI is not supported at the selected AMF or TAI being processed by the AMF 70. When the AMF 70 receives a Pending S-NSSAI rejected by the NSSF 76 (e.g., the reject NSSAI received from the NSSF 76), the AMF 70 shall remove the S-NSSAI from the Pending NSSAI list (e.g., the Pending NSSAI of the AMF 70) and send to the UE 3, within the reject NSSAI or the extended reject NSSAI, the reason for rejection (e.g., the S-NSSAI is not supported in the registration area, or the S-NSSAI is not supported in the tracking area, or the S-NSSAI is not supported in the PLMN or other existing cause values). When the UE 3 receives the reject NSSAI in a NAS message from the AMF 70, the UE 3 shall remove the S-NSSAI from the Pending NSSAI list (e.g., the Pending NSSAI of the UE 3) and operate according to the received cause value.

[0097] For example, assume that the UE 3 executes a first registration procedure by sending a first registration request message including a first Requested NSSAI (e.g., the first Requested NSSAI for one access) via one access to the AMF 70. The first Requested NSSAI may include S-NSSAI1. S-NSSAI1 is subject to the NSSAA procedure.

[0098] Thereafter, the NSSAA procedure for S-NSSAI1 proceeds.

[0099] In this case, the UE3 and the AMF70 have a first Pending NSSAI for one access that includes the S-NSSAI1.

[0100] Then, while the NSSAA procedure for the S-NSSAI1 is in progress, the UE3 also executes a second registration procedure by sending a second registration request message that includes a second Requested NSSAI (e.g., a second Requested NSSAI for another access) via another access to the same AMF70. The second Requested NSSAI may include the S-NSSAI2. The S-NSSAI2 is subject to the NSSAA procedure.

[0101] Thereafter, the NSSAA procedure for the S-NSSAI2 proceeds (i.e., the NSSAA procedures for the S-NSSAI1 and the S-NSSAI2 proceed).

[0102] In this case, the UE3 and the AMF70 also have a second Pending NSSAI for another access that includes the S-NSSAI2.

[0103] One access may be 3GPP access, another access may be non-3GPP access, or vice versa.

[0104] If the second registration procedure requires the AMF reallocation procedure in section 4.2.2.2.3 of 3GPP TS 23.502 [3], the AMF70 may send an Nnssf_NSSelection_Get message that includes the first Pending NSSAI and the second Pending NSSAI to the NSSF76. The Nnssf_NSSelection_Get message may include at least one of the first Requested NSSAI for one access and the second Requested NSSAI for another access.

[0105] The Nnssf_NSSelection_Get message can include the mapping of the Pending NSSAI. For example, the Nnssf_NSSelection_Get message can include at least one of the mapping of the first Pending NSSAI and the mapping of the second Pending NSSAI.

[0106] When NSSF76 receives the Nnssf_NSSelection_Get message, NSSF76 can determine a list of AMF sets or AMF addresses taking into account both the first Pending NSSAI and the second Pending NSSAI.

[0107] In addition, when NSSF76 receives the Nnssf_NSSelection_Get message, NSSF76 can determine a list of AMF sets or AMF addresses taking into account at least one of the first Requested NSSAI, the second Requested NSSAI, the first Pending NSSAI, and the second Pending NSSAI.

[0108] For example, NSSF76 can discover the AMF(s) that can handle the S-NSSAI(s) in at least one of the first Requested NSSAI, the second Requested NSSAI, the first Pending NSSAI, and the second Pending NSSAI.

[0109] For example, NSSF76 can discover the AMF(s) that can handle S-NSSAI1 and S-NSSAI2. NSSF76 can include the discovered AMF(s) in the AMF set or include the addresses of the discovered AMF(s) in the list of AMF addresses.

[0110] In addition, when the NSSF 76 receives the Nnssf_NSSelection_Get message, the NSSF 76 can determine a first permitted NSSAI for one access and a second permitted NSSAI for the other access, taking into account both the first Pending NSSAI and the second Pending NSSAI.

[0111] In addition, when the NSSF 76 receives the Nnssf_NSSelection_Get message, the NSSF 76 can determine a first permitted NSSAI for one access and a second permitted NSSAI for another access, taking into account at least one of the first Requested NSSAI, the second Requested NSSAI, the first Pending NSSAI, and the second Pending NSSAI.

[0112] For example, when determining the first permitted NSSAI and the second permitted NSSAI, the NSSF 76 can extract the S-NSSAI 1 included in the first Pending NSSAI and the S-NSSAI 2 included in the second Pending NSSAI from at least one of the first permitted NSSAI and the second permitted NSSAI.

[0113] Then, the NSSF 76 sends an Nnssf_NSSelection_Get response message to the AMF 70. The Nnssf_NSSelection_Get response message may include at least one of a list of AMF sets or AMF addresses, a first permitted NSSAI for one access, a mapping of the first permitted NSSAI, a second permitted NSSAI for another access, a mapping of the second permitted NSSAI, NSI ID(s), NRF(s), a list of rejection (S-NSSAI(s), cause value)(s), a configured NSSAI for the serving PLMN, a mapping of the configured NSSAI, a first Pending NSSAI for one access, a second Pending NSSAI for another access, a mapping of the first Pending NSSAI, and a mapping of the second Pending NSSAI.

[0114] If the S-NSSAI(s) within the Pending NSSAI for any access is / are not supported by the set of AMFs selected by the NSSF 76 or the AMF(s) in the list of AMF addresses (e.g., when the NSSF 76 cannot determine a suitable set of AMFs or a suitable list of AMF addresses for the first and second Pending NSSAI), the NSSF 76 can include the S-NSSAI(s) within the Pending NSSAI in the reject NSSAI for that access (e.g., at least one of one access and another access), along with the reason for which it was rejected. The reason can indicate, for example, that the Pending NSSAI(s) (e.g., the S-NSSAI(s) within the Pending NSSAI) is / are not supported in the selected AMF or the TAI(s) processed by the AMF.

[0115] For example, if the S-NSSAI(s) within the Pending NSSAI for any access (e.g., both one access and another access) is / are not supported by the set of AMFs selected by the NSSF 76 or the AMF(s) in the list of AMF addresses (e.g., when the NSSF 76 cannot determine a suitable set of AMFs or a suitable list of AMF addresses for the first and second Pending NSSAI), the NSSF 76 can include the S-NSSAI(s) within the first and second Pending NSSAI in the reject NSSAI. For example, the NSSF 76 can include the S-NSSAI(s) in at least one of a first reject NSSAI for one access and a second reject NSSAI for another access. The first reject NSSAI and the second reject NSSAI can be one (or a common) reject NSSAI.

[0116] Furthermore, the NSSF 76 can set a cause or cause value indicating that at least one of the S-NSSAI(s) in the first Pending NSSAI and the second Pending NSSAI is not supported by the selected AMF, or is not supported in the TAI(s) (e.g., TA(s) indicated by the TAI(s)) processed by the selected AMF.

[0117] The NSSF 76 can send an Nnssf_NSSelection_Get response message including at least one of the first rejected NSSAI, the second rejected NSSAI, and the cause value. The Nnssf_NSSelection_Get response message may also include other parameters described above.

[0118] For example, if the S-NSSAI(s) in the first Pending NSSAI is not supported by the AMF(s) in the AMF set or the AMF(s) in the list of AMF addresses selected by the NSSF 76, and the S-NSSAI(s) in the second Pending NSSAI is supported by the AMF(s) in the AMF set or the AMF(s) in the list of AMF addresses selected by the NSSF 76, the NSSF 76 can put the S-NSSAI(s) in the first Pending NSSAI into the first rejected NSSAI for one access. The NSSF 76 can put the S-NSSAI(s) in the second Pending NSSAI into the second permitted NSSAI for another access.

[0119] Furthermore, the NSSF 76 can set a cause or cause value indicating that the S-NSSAI in the first Pending NSSAI is not supported by the selected AMF, or is not supported in the TAI(s) (e.g., TA(s) indicated by the TAI(s)) processed by the selected AMF.

[0120] NSSF76 can send an Nnssf_NSSelection_Get response message that includes at least one of a first rejected NSSAI, a cause value, and a second permitted NSSAI. The Nnssf_NSSelection_Get response message may include other parameters described above.

[0121] When AMF70 receives at least one of a first permitted NSSAI for one access and a second permitted NSSAI for another access, AMF70 can send at least one of the first permitted NSSAI for one access and the second permitted NSSAI for another access to UE3. For example, AMF70 can send the first permitted NSSAI for one access to UE3 via one access.

[0122] For example, AMF70 can send the second permitted NSSAI for another access to UE3 via another access.

[0123] When AMF70 receives at least one of a first rejected NSSAI for one access and a second rejected NSSAI for another access, AMF70 can send at least one of the first rejected NSSAI for one access and the second rejected NSSAI for another access to UE3.

[0124] For example, AMF70 can send the first rejected NSSAI for one access to UE3 via one access.

[0125] For example, AMF70 can send the second rejected NSSAI for another access to UE3 via another access.

[0126] Second example of the first aspect: A second example of the first aspect discloses a method by which UE3 transmits the Pending NSSAI to RAN5 and AMF70 when UE3 holds the Pending NSSAI. Then, AMF70 transmits an Nnssf_NSSelection_Get message including the Pending NSSAI received from UE3, in addition to the Requested NSSAI, to NSSF76 to discover an AMF appropriate for serving UE3.

[0127] The Radio Access Network (RAN) may be expressed as a RAN node or an (R)AN node.

[0128] Hereinafter, with reference to FIG. 2, a detailed process of the second example of the first aspect will be described.

[0129] Step 0. UE3 is in the CM-IDLE state, and UE3 holds the Pending NSSAI in UE3's storage. This may occur, for example, after the registration procedure when the NSSAA procedure has not yet been initiated by the AMF and UE3 enters the CM-IDLE state. The CM-IDLE state may be expressed as the CM-IDLE mode. For example, UE3 is in the CM-IDLE state and UE3 holds the Pending NSSAI.

[0130] Step 1. UE3 transmits a Radio Resource Control (RRC) Setup Request message to RAN5. The trigger for the RRC Setup Request message in UE3 may be that an application in UE3 requests to establish a new PDU session(s) with S-NSSAI(s) not yet requested for 5GS. For example, UE3 in the CM-IDLE state can transmit an RRC Setup Request message. For example, UE3 can transmit an RRC Setup Request message while the NSSAA procedure has not yet been initiated by the AMF after the registration procedure.

[0131] Step 2. RAN5 sends an RRC Setup message to UE3. For example, when RAN5 receives an RRC Setup Request message, RAN5 can send an RRC Setup message.

[0132] Step 3. UE3 sends an RRC Setup Complete message including the registered AMF, 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), Requested NSSAI, Pending NSSAI, and a Non-Access-Stratum (NAS) container to RAN5. The NAS container includes a registration request message. The registration request message in the NAS container includes the Requested NSSAI and the Pending NSSAI. If UE3 holds the Pending NSSAI in UE3's storage, UE3 incorporates the Pending NSSAI into both the RRC Setup Complete message and the registration request message.

[0133] For example, UE3 can include the Pending NSSAI that UE3 held in Step 0 in both the RRC Setup Complete message and the registration request message.

[0134] For example, UE3 can send at least one of the S-NSSAI(s) included in the Requested NSSAI and the S-NSSAI(s) included in the Pending NSSAI.

[0135] At least one of the S-NSSAI(s) included in the Requested NSSAI and the S-NSSAI(s) included in the Pending NSSAI may be included in at least one of the RRC Setup Complete message and the registration request message.

[0136] UE3 can send a Pending NSSAI (e.g., one or more S-NSSAIs included in the Pending NSSAI) for registration by the AMF reallocation procedure.

[0137] The Pending NSSAI (e.g., one or more S-NSSAIs included in the Pending NSSAI) in at least one of the RRC setup complete message and the registration request message may be used for registration by the AMF reallocation procedure.

[0138] In one example, sending the Pending NSSAI in the RRC setup complete message and the registration request message may be independent of each other. For example, if UE3 includes the Pending NSSAI in the RRC setup complete message, the UE may or may not include the Pending NSSAI in the registration request message. Similarly, if UE3 includes the Pending NSSAI in the registration request message, UE3 may or may not include the Pending NSSAI in the RRC setup complete message.

[0139] For example, when UE3 receives an RRC setup message, UE3 can send an RRC setup complete message.

[0140] Step 4. When RAN5 receives an RRC setup complete message from UE3, if RAN5 cannot reach AMF70 indicated in the Registered AMF within the received RRC setup complete message, RAN5 checks both the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI to discover the AMF. This can occur when UE3 moves to another PLMN before the NSSAA procedure is initiated by AMF70 in the previous PLMN. For example, RAN5 can discover AMF70 using both the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI. For example, RAN5 can discover AMF70 using at least one of the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI.

[0141] Otherwise, RAN5 discovers AMF70 based on the received Registered AMF in the RRC setup complete message.

[0142] RAN5 sends an Initial UE message containing the registration request message received from UE3 in Step 3 to AMF70.

[0143] The Initial UE message can include the Pending NSSAI. For example, the Initial UE message may include the Pending NSSAI received from UE3 in Step 3.

[0144] The Initial UE message can include the Requested NSSAI. For example, the Initial UE message can include the Requested NSSAI received from UE3 in Step 3.

[0145] For example, when RAN5 receives an RRC setup complete message, RAN5 can send an initial UE message to the AMF discovered by RAN5.

[0146] For example, when RAN5 receives an RRC setup complete message, RAN5 may send an initial UE message to the AMF indicated by the registered AMF received in the RRC setup complete message.

[0147] Step 5. Steps 2 to 3c are performed as described in the registration according to the AMF reallocation procedure in section 4.2.2.2.3 of 3GPP TS 23.502 [3]. For example, part of steps 2 to 3c may be performed.

[0148] Step 6. AMF70 sends an Nnssf_NSSelection_Get message containing the Requested NSSAI and the Pending NSSAI to NSSF76. The Requested NSSAI is incorporated by AMF70 by copying it from the registration request message received from UE3 via RAN5 in step 4. The Pending NSSAI is incorporated by AMF70 by copying it from the registration request message received from UE3 via RAN5 in step 4.

[0149] For example, in step 3, if UE3 sends a registration request message containing a Requested NSSAI including S-NSSAI1, AMF70 includes the Requested NSSAI including S-NSSAI1 in the Nnssf_NSSelection_Get message.

[0150] For example, in step 3, if UE3 sends a registration request message containing a Pending NSSAI including S-NSSAI2, AMF70 includes the Pending NSSAI including S-NSSAI2 in the Nnssf_NSSelection_Get message.

[0151] AMF70 can execute step 6 in the same way as step 2 in FIG. 1 by using at least one of the received Requested NSSAI and the received Pending NSSAI.

[0152] Step 7. NSSF76 sends an Nnssf_NSSelection_Get response message including a list of AMF sets or AMF addresses and a permitted NSSAI to AMF70. NSSF76 takes into account the received Requested NSSAI and the received Pending NSSAI to discover a list of AMF sets or AMF addresses.

[0153] NSSF76 can discover or determine a list of AMF sets or AMF addresses in the same way as in the first example of the first aspect.

[0154] NSSF76 can discover or determine a list of AMF sets or AMF addresses in the same way as step 3 in the first example of the first aspect.

[0155] Step 8. Steps 5 to 8 are performed as described in the registration by AMF reallocation in section 4.2.2.2.3 of 3GPP TS 23.502 [3]. For example, some of steps 5 to 8 may be performed.

[0156] In one example, at step 7a of case (A) of registration according to the AMF reallocation procedure in section 4.2.2.2.3 of 3GPP TS 23.502 [3], the initial AMF (e.g., AMF 70) can include the Pending NSSAI in the Namf_Communication_N1MessageNotify message. When receiving a Namf_Communication_N1MessageNotify message including the Pending NSSAI at the target AMF (e.g., the AMF discovered or selected by the NSSF 76 in at least one of steps 5 to 7), the target AMF can start the NSSAA procedure for each S-NSSAI present in the received Pending NSSAI. For example, the target AMF can start the NSSAA procedure for the S-NSSAI(s) present in the received Pending NSSAI. This process example may be applied to the first example of the first aspect.

[0157] In another example, in step 7a of case (B) of the registration procedure by AMF reallocation in section 4.2.2.2.3 of 3GPP TS 23.502 [3], the initial AMF (e.g., AMF70) can include the Pending NSSAI in the Reroute NAS message (i.e., the Reroute NAS request message) and send the Reroute NAS message to the NG-RAN (e.g., RAN5). When receiving the Reroute NAS message including the Pending NSSAI in the NG-RAN, the NG-RAN can select the target AMF (e.g., the target AMF may be the AMF discovered or selected by the NSSF76 in at least one of steps 5 to 7) using at least one of the Pending NSSAI and the allowed NSSAI. The allowed NSSAI may be included in the Reroute NAS message or stored by the NG-RAN. When receiving the Reroute NAS message including the Pending NSSAI in the NG-RAN, the NG-RAN sends the initial UE message including the Pending NSSAI received from the initial AMF to the target AMF in step 7a of case (B). When receiving the initial UE message including the Pending NSSAI at the target AMF, the target AMF can start the NSSAA procedure for each S-NSSAI existing in the received Pending NSSAI. For example, the target AMF can start the NSSAA procedure for the S-NSSAI(s) existing in the received Pending NSSAI. This process example may be applied to the first example of the first aspect.

[0158] According to the second example of the first aspect, for example, the UE3 includes the Pending NSSAI in at least one of the RRC setup complete message and the registration request message. The NSSF76 takes the Pending NSSAI into account to discover a list of AMF sets or AMF addresses.

[0159] According to the second example of the first aspect, the above problems can be solved. For example, in the second example of the first aspect, since the newly selected AMF cannot process or support S-NSSAI(s), after the NSSAA procedure, all services(s) that use the S-NSSAI(s) newly added to the permitted NSSAI may not be provided to the UE. For example, the second example of the first aspect can solve problems such as significant service degradation of all services(s) using network slices in 5GS.

[0160] Variant 1 of the second example of the first aspect: When UE3 is in the CM-CONNECTED state (for example, when UE3 is in the CM-CONNECTED state in step 0), for example, the NSSAA procedure is in progress immediately after the previous registration procedure, and the following changes are required in the call flow (or process) of FIG. 2. - Steps 1 and 2 are deleted. - The RRC setup complete message in step 3 is replaced by an RRC UL information transfer message or an Up Link (UL) information transfer message that includes an NAS container. The NAS container includes a registration request message. The registration request message in the NAS container includes the Requested NSSAI and the Pending NSSAI. - The initial UE message in step 4 is replaced by an Uplink NAS Transport message. The Uplink NAS Transport message includes the registration request message received from UE3 in step 3.

[0161] The CM-CONNECTED state may also be expressed as the CM-CONNECTED mode.

[0162] Variant 2 of the second example of the first aspect: The network operator can have a setting or policy regarding whether a network slice(s) (or S-NSSAI(s)) from the Pending NSSAI within UE3 needs to be included by UE3 in the Pending NSSAI for RAN5 in the RRC setup complete message for AMF selection and / or whether it needs to be included by UE3 in the Pending NSSAI for AMF70 in the registration request message for AMF reallocation. Regarding the setting or policy, a new rule (e.g., a new rule part of a UE Route Selection Policy (URSP) rule) within the UE policy can be defined and can be set by the network operator on a per UE granularity basis.

[0163] For example, in step 3 of Figure 2, when determining whether to include a network slice(s) (or S-NSSAI(s)) from the Pending NSSAI in at least one of the RRC setup complete message, the registration request message, and the UL information transfer message, UE3 can use the network operator's setting or policy in UE3.

[0164] For example, in step 3 of Figure 2, UE3 can determine whether to include the Pending NSSAI (e.g., S-NSSAI(s) within the Pending NSSAI) in at least one of the RRC setup complete message, the registration request message, and the UL information transfer message based on the network operator's setting or policy in UE3.

[0165] For example, in step 3 of FIG. 2, the UE3 can use the settings or policies of the network operator within the UE3 to determine which network slice(s) (or S-NSSAI(s)) of the Pending NSSAI need to be included in at least one of the RRC setup complete message, the registration request message, and the UL information transfer message.

[0166] Modification Example 3 of the Second Example of the First Aspect: In step 3, instead of adding the Pending NSSAI to the RRC setup complete message and the registration request message, the UE3 can add the S-NSSAI(s) within the Pending NSSAI to the Requested NSSAI in at least one of the RRC setup complete message and the registration request message. As a result, the Requested NSSAI in at least one of the RRC setup complete message and the registration request message can include the S-NSSAI(s) that the UE3 requests to register and the S-NSSAI(s) from the Pending NSSAI within the UE3.

[0167] For example, if the UE3 has a Pending NSSAI that includes S-NSSAI1, the UE3 can include S-NSSAI1 in the Requested NSSAI in at least one of the RRC setup complete message and the registration request message. In this case, the UE3 may not need to include the Pending NSSAI in at least one of the RRC setup complete message and the registration request message.

[0168] RAN5 can send the registration request message to AMF70, and AMF70 can send the Nnssf_NSSelection_Get message to NSSF76.

[0169] When NSSF76 receives the Nnssf_NSSelection_Get message, NSSF76 can find a set of AMFs or a list of AMF addresses based on the received Requested NSSAI.

[0170] Variant 4 of the second example of the first aspect: In the second example as well, the same principle as Variant 5 of the first example of the first aspect can be applied. For example, when an NSSAA is in progress via one access (e.g., UE3 has a Pending NSSAI for one access) and UE3 is in the state of step 0 via another access (e.g., UE3 is in the CM-IDLE state and holds a Pending NSSAI for another access), UE3 can use at least one of the RRC setup complete message, registration request message, and UL information transfer message to send the Pending NSSAIs for one access and another access to RAN5. When receiving at least one of the messages, RAN5 can use at least one of the initial UE message and uplink NAS transport message to send the Pending NSSAI to AMF70.

[0171] Then, AMF70 can execute the same process as Variant 5 of the first example of the first aspect.

[0172] System overview FIG. 3 schematically shows a telecommunication system 1 for mobile (cellular or wireless) to which each of the above-described aspects can be applied.

[0173] The telecommunication system 1 represents an end-to-end communication-capable system overview. For example, UE3 (or user equipment, "mobile device", 3) communicates with other UE3s or service servers in the data network 20 via respective (R)AN nodes 5 and the core network 7.

[0174] (R)AN node 5 supports any radio access including 5G radio access technology (RAT), E-UTRA radio access technology, RAT beyond 5G, 6G RAT, and non-3GPP RAT, including wireless local area network (WLAN) technology defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0175] (R)AN node 5 can be divided into a radio unit (RU), a distributed unit (DU), and a centralized unit (CU). In some embodiments, each of the units can be connected to each other and (R)AN node 5 can be constructed by adopting the architecture defined by the Open RAN (O-RAN) Alliance, and these units are called O-RU, O-DU, and O-CU, respectively.

[0176] (R)AN node 5 may be divided into a control plane function and a user plane function. Further, multiple user plane functions can be assigned to support communication. In some embodiments, user traffic may be distributed among multiple user plane functions, and user traffic through each user plane function is aggregated at both UE3 and (R)AN node 5. This split architecture may be referred to as "dual connectivity" or "multi-connectivity".

[0177] (R)AN node 5 can also support communication using satellite access. In some embodiments, (R)AN node 5 can support satellite access and terrestrial access.

[0178] Also, the (R)AN node 5 can be regarded as an access node for non-wireless access. Non-wireless access includes fixed-line access as defined by the Broadband Forum (BBF) and optical access as defined by Innovative Optical and Wireless Network (IOWN).

[0179] The core network 7 can include logical nodes (or "functions") for supporting communications in the telecommunications system 1. For example, the core network 7 may be a 5G Core Network (5GC) that includes, among other functions, a control plane function and a user plane function. Each function within the logical node can be regarded as a network function. The network function may be provided to another node by conforming to a service-based architecture (SBA).

[0180] The network function can be deployed as a distributed, redundant, stateless, and scalable one that serves from several locations and several execution instances at each location by conforming to network virtualization technologies defined as European Telecommunications Standards Institute - Network Functions Virtualization (ETSI NFV).

[0181] 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 non-public network (PNI-NPN).

[0182] As is well known, when UE3 moves within the geographical area covered by the telecommunication system 1, UE3 can enter and exit the area (i.e., radio cell) served by the (R)AN node 5. To track UE3 and facilitate its movement between different (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, instead of the AMF 70, a Mobility Management Entity (MME) or a mobility management node beyond 5G or a mobility management node of 6G can be used.

[0183] The core network 7 also includes, among others, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, an Authentication Server Function (AUSF) 74, a Unified Data Management (UDM) 75, and a Network Slice-Specific Authentication and Authorization Function (NSSAAF) 76. When UE3 is roaming in a visited Public Land Mobile Network (PLMN), the Home Public Land Mobile Network (HPLMN) of UE3 provides the roaming-out UE3 with the UDM 75 and at least a part of the functions of the SMF 71, the UPF 72, and the PCF 73.

[0184] UE3 is connected to each serving (R)AN node 5 via an appropriate air interface (e.g., the so-called "Uu" interface, etc.). Adjacent (R)AN nodes 5 are interconnected with each other via an (R)AN node interface (such as the so-called "Xn" interface, etc.) through an appropriate (R)AN node 5. Each (R)AN node 5 is also connected to a node (such as a so-called core network node, etc.) within the core network 7 via an appropriate interface (such as the so-called "N2" / "N3" interface(s), etc.). A connection to the data network 20 is also provided from the core network 7. The data network 20 can be a PLMN's Internet, a public network, an external network, a private network, or an internal network. When the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), the IP Multimedia Subsystem (IMS) service may 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.

[0185] The "Uu" interface may include a control plane of the Uu interface and a user plane of the Uu interface. 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 via a physical connection.

[0186] The control plane of the Uu interface is responsible for establishing, changing, and releasing the connection between UE3 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 via a physical connection.

[0187] For example, the following messages are communicated via the RRC layer to support AS signaling. - RRC Setup Request message: This message is sent from UE3 to (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 randomValue. - RRC Setup message: This message is sent from (R)AN node 5 to UE3. 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 - RRC Setup Complete message: This message is sent from UE3 to (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

[0188] UE3 and AMF70 are connected via an appropriate interface (e.g., the so-called N1 interface, etc.). The N1 interface serves to provide communication between UE3 and AMF70 to support NAS signaling. The N1 interface may be established via 3GPP access and via non-3GPP access. For example, the following messages are communicated via the N1 interface. - 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 identification information, non-current native NAS key set identifier, 5GMM capabilities, UE security capabilities, Requested NSSAI, last visited registered TAI, S1 UE network capabilities, uplink data status, PDU session status, MICO indication, UE status, additional GUTI, allowed PDU session status, UE usage settings, requested DRX parameters, EPS NAS message container, LADN indication, payload container type, payload container, network slicing indication, 5GS update type, mobile station class mark 2, supported codecs, NAS message container, EPS bearer context status, requested extended DRX parameters, T3324 value, UE radio capabilities ID, requested mapped NSSAI, requested information, requested WUS support information, N5GC indication, and requested NB-N1 DRX parameters. - Registration acceptance 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 registration acceptance message. - 5GS registration result, 5G-GUTI, equivalent PLMN, TAI list, permitted NSSAI, rejected NSSAI, configured NSSAI, 5GS network function 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 registration timer value, T3502 value, emergency number list, extended emergency number list, SOR transparent container, EAP message, NSSAI inclusion mode, operator-defined access category definition, negotiated DRX parameters, non-3GPP NW policy, EPS bearer context status, negotiated extended DRX parameters, T3447 value, T3448 value, T3324 value, UE radio capability ID, UE radio capability ID deletion indication, Pending NSSAI, encryption key data, CAG information list, truncated 5G-S-TMSI configuration, negotiated WUS support information, negotiated NB-N1 mode DRX parameters, and extended rejected NSSAI. - 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 also be included together in the registration complete message. - SOR transparent container. - 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 also 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. - 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 also be incorporated together in the authentication response message. - Authentication response message identity, authentication response parameters, and EAP message. - Authentication result 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 be incorporated into the authentication result message together. - ngKSI, EAP message, and ABBA. - Authentication failure message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be incorporated into the authentication failure message together. - Authentication failure message identification information, 5GMM cause, and authentication failure parameters. - Authentication rejection 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 be input into the authentication rejection message together. - EAP message. - Service request message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be incorporated into the service request message together. - ngKSI, service type, 5G-S-TMSI, uplink data status, PDU session status, permitted PDU session status, NAS message container. - Service acceptance 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 be incorporated into the service acceptance message together. - PDU session status, PDU session reactivation result, cause of PDU session reactivation result error, EAP message, and T3448 value. - Service rejection 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 be incorporated into the service rejection message together. - 5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list. - 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 be incorporated together into the configuration update command message. - Configuration update indication, 5G-GUTI, TAI list, permitted NSSAI, service area list, full network name, network short name, 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 definition, 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. - Configuration update complete message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be incorporated together into the configuration update complete message. - Configuration update complete message identification information.

[0189] User Equipment (UE) FIG. 4 is a block diagram showing the main components of UE3 (Mobile Device 3). As shown in the figure, UE3 includes a transceiver circuit 31 operable to transmit signals to and receive signals from one or more nodes (multiple possible) connected via one or more antennas 32. Further, UE3 can include a user interface 34 for inputting external information or outputting information to the outside. Although not necessarily shown in the figure, UE3 can have all the normal functions of a conventional mobile device, which can be provided by any one or any combination of hardware, software, and firmware as required. The software may be pre-installed in the memory and / or downloaded, for example, via a telecommunication network or from a removable data storage device (ReMovable data storage Device: RMD). The control unit 33 controls the operation of UE3 according to the software stored in the memory 36. The software includes, among other things, 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 can include, for example, appropriately formatted signaling messages (e.g., registration request messages and related response messages) regarding access and mobility management procedures (for UE3). The control unit 33 interacts with one or more Universal Subscriber Identity Modules (USIM) 35. If multiple USIMs 35 are equipped, the control unit 33 may activate only one USIM 35 or multiple USIMs 35 simultaneously.

[0190] 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).

[0191] UE3 can be, for example, an item of equipment for production or manufacturing and / or energy-related machinery (such as boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal power plants, 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, dies or molds, rolls, conveyors, elevators, material handling devices, textile machinery, sewing equipment, printing and / or related machinery, paper converting devices, chemical machinery, mining machinery and / or construction machinery and / or related facilities, machinery and / or appliances for agriculture, forestry and / or fisheries, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission devices, lubrication devices, valves, pipe fittings, and / or application systems for any of the aforementioned equipment or machinery, etc.).

[0192] UE3 can be, for example, an item of transportation equipment (such as transportation equipment like rolled materials, automobiles, motorcycles, bicycles, trains, buses, carts, human-powered vehicles, ships and other vessels, aircraft, rockets, satellites, drones, balloons, etc.).

[0193] UE3 can be, for example, an item of information and communication equipment (such as information and communication equipment like electronic computers and related equipment, communication and related equipment, electronic components, etc.).

[0194] UE3 may be, for example, an item of a refrigerator, a refrigerator application product, a commodity and / or a service industry device, a vending machine, an automatic service machine, an office machine or device, a consumer electronic device and (for example, a consumer electronic device such as an audio device, a video device, a speaker, a radio, a television, a microwave oven, a rice cooker, a coffee machine, a dishwasher, a washing machine, a dryer, an electric fan or a related device, a vacuum cleaner, etc.) an electronic device.

[0195] UE3 may be, for example, an electric application system or device (for example, an electric application system or device such as an X-ray system, a particle accelerator, a radioisotope device, a sonic device, an electromagnetic application device, an electronic power application device, etc.).

[0196] UE3 may be, for example, an electronic lamp, a lighting fixture, a measuring device, an analyzer, a tester, or a surveying or sensing device (a surveying or sensing device such as a smoke detector, a human sensor, a motion sensor, a wireless tag, etc.), a wristwatch or a clock, an inspection device, an optical device, a medical device and / or system, a weapon, an item of tableware, a hand tool, etc.

[0197] UE3 may be, for example, a mobile information terminal of wireless equipment or a related device (for example, a wireless card or module designed to be attached to or inserted into another electronic device (for example, a personal computer, an electric measuring instrument)).

[0198] UE3 may be a part of a device or system that uses various wired and / or wireless communication technologies to provide applications, services, and solutions described later regarding the "Internet of Things (IoT)".

[0199] Internet of Things devices (or "things") can be equipped with appropriate electronics, software, sensors, network connectivity, etc. that enable these devices to collect and exchange data with each other and with other communication devices. IoT devices may include automated devices that follow software instructions stored in internal memory. IoT devices can operate without the need for human supervision or interaction. IoT devices can also remain stationary and / or inactive for long periods of time. IoT devices may be implemented (generally) as part of a fixed installation. IoT devices may also be embedded in non-fixed devices (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0200] It will be understood that IoT technology can be implemented on any communication device that can be connected to a communication network to send / receive data, whether or not such communication devices are controlled by human input or software instructions stored in memory.

[0201] 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 (NB)-IoT UEs. It will be understood that UE3 can support one or more IoT or MTC applications.

[0202] UE3 may be a smartphone or a wearable device (e.g., smart glasses, smartwatch, smart ring, or hearable device).

[0203] UE3 may be an automobile, a connected automobile, a self-driving automobile, a vehicle device, a motorcycle, or a V2X (Vehicle to Everything) 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).

[0204] (R)AN node FIG. 5 is a block diagram showing the main components of an exemplary (R)AN node 5, such as a base station (e.g., "eNB" in LTE, "gNB" in 5G, subsequent 5G base stations, 6G base stations). As shown, the (R)AN node 5 includes a transceiver circuit 51 operable to transmit signals to and receive signals from one or more UEs 3 connected 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. The control unit 54 controls the operation of the (R)AN node 5 according to software stored in the memory 55. The software may be pre-installed in the memory and / or may be downloaded, for example, via a telecommunications network or from a removable memory device (ReMovable memory Device: RMD). The software includes, among other things, an operating system 551 and a communication control module 552 having at least a transceiver control module 5521.

[0205] 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 (e.g., directly or indirectly). The signaling can include, for example, properly formatted signaling messages related to the radio connection and connection to the core network 7 (for a specific UE 3), in particular, connection establishment and maintenance (e.g., RRC connection establishment and other RRC messages), Next Generation Application Protocol (NGAP) messages (i.e., messages at the N2 reference point) and Xn application protocol (XnAP) messages (i.e., messages at the Xn reference point). Such signaling can also include, for example, broadcast information (e.g., master information and system information) in a transmission case.

[0206] When implemented, the control unit 54 is also set (by software or hardware) to process related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0207] (R)AN node 5 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).

[0208] System overview of (R)AN node 5 based on the O-RAN architecture FIG. 6 schematically shows the (R)AN node 5 based on the O-RAN architecture to which the aspect of the (R)AN node 5 is applicable.

[0209] The (R)AN node 5 based on the O-RAN architecture represents a system overview in which the (R)AN node is divided into a Radio Unit (RU) 60, a Distributed Unit (DU) 61, and a Centralized Unit (CU) 62. In some embodiments, the units can be combined. For example, the RU 60 can be integrated / aggregated with the DU 61 as an integrated / aggregated unit, and the DU 61 can be integrated / aggregated with the CU 62 as another integrated / aggregated unit. Any function in the description of a unit (e.g., one of the RU 60, DU 61, and CU 62) can be implemented in the above integrated / aggregated units. Further, the CU 62 can be separated into two functional units such as a CU Control Plane (CP) and a CU User Plane (UP). The CU CP has control plane functions in the (R)AN node 5. The CU UP has user plane functions in the (R)AN node 5. Each CU CP is connected to the CU UP via an appropriate interface "E1".

[0210] The UE 3 and each serving RU 60 are connected via an appropriate air interface "Uu". Each RU 60 is connected to the DU 61 via an appropriate interface (e.g., so-called "front haul", "open front haul", "F1" interface, etc.). Each DU 61 is connected to the CU 62 via an appropriate interface (e.g., so-called "mid haul", "open mid haul", "E2" interface, etc.). Each CU 62 is also connected to a node (e.g., so-called core network node, etc.) in the core network 7 via an appropriate interface (e.g., so-called "back haul", "open back haul", "N2" / "N3" interface(s), etc.). Further, the user plane portion of the DU 61 may be connected to the core network 7 via an appropriate interface (e.g., so-called "N3" interface(s), etc.).

[0211] According to the functions divided among RU60, DU61, and CU62, each unit provides a part of the functions provided by the (R)AN node 5. For example, RU60 can provide functions for communicating with UE3 via the air interface, DU61 can provide functions for supporting the MAC layer and the RLC layer, and CU62 can provide functions for supporting the PDCP layer, the SDAP layer, and the RRC layer.

[0212] Radio Unit (RU) Figure 7 is a block diagram showing the main components of an exemplary RU60, for example, the RU part of a base station (such as "eNB" in LTE, "gNB" in 5G, subsequent 5G base stations, 6G base stations). As shown, RU60 includes a transceiver circuit 601 operable to transmit signals to and receive signals from one or more UEs 3 connected via one or more antennas 602, and to transmit signals to and receive signals from other network nodes or network units (directly or indirectly) via a network interface 603. A control unit 604 controls the operation of RU60 according to software stored in a memory 605. The software may be pre-installed in the memory and / or may be downloaded, for example, via a telecommunications network or from a removable memory device (ReMovable memory Device: RMD). The software includes, among other things, an operating system 6051 and a communication control module 6052 having at least a transceiver control module 60521.

[0213] The communication control module 6052 is responsible for processing (generating / sending / receiving) signaling between the RU 60 (using its transceiver control sub-module) and other nodes or units such as the UE 3, another RU 60, and the DU 61, for example, directly or indirectly. The signaling can include, for example, radio connections and connections with the RU 60 for a specific UE 3, in particular, properly formatted signaling messages related to the MAC layer and the RLC layer.

[0214] When implemented, the control unit 604 is also set (by software or hardware) to process related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0215] The RU 60 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).

[0216] As described above, the RU 60 can be integrated / connected with the DU 61 as an integrated / connection unit. Any function in the description of the RU 60 can be implemented in the above integrated / connection unit.

[0217] Distributed Unit (DU) FIG. 8 is a block diagram showing the main components of the DU part of an exemplary DU61, such as a base station (e.g., "eNB" in LTE, "gNB" in 5G, subsequent 5G base stations, 6G base stations). As shown, the apparatus includes a transceiver circuit 611 operable to transmit signals to and receive signals from other nodes or units (including RU60) via a network interface 612. A control unit 613 controls the operation of the DU61 according to software stored in a memory 614. The software may be pre-installed in the memory 614 and / or may be downloaded, for example, via a telecommunications network or from a removable memory device (RMD). The software includes, among other things, 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) serves to process (generate / transmit / receive) signaling between the DU61 and the RU60 and other nodes or units such as other nodes or units.

[0218] The DU 61 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).

[0219] As described above, the RU60 can be integrated / connected with the DU61 or CU62 as an integrated / connection unit. Any function in the description of the DU61 can be implemented by one of the above integrated / connection units.

[0220] Centralized Unit (CU) FIG. 9 is a block diagram showing the main components of an exemplary CU62, for example, the CU part of a base station (e.g., "eNB" in LTE, "gNB" in 5G, subsequent 5G base stations, 6G base stations). As shown, the apparatus includes a transceiver circuit 621 operable to transmit signals to and receive signals from other nodes or units (including DU61) via a network interface 622. A control unit 623 controls the operation of the CU62 according to software stored in a memory 624. The software may be pre-installed in the memory 624 and / or may be downloaded, for example, via a telecommunications network or from a removable memory device (ReMovable memory Device: RMD). The software includes, among other things, 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) serves to process (generate / transmit / receive) signaling between the CU62 and other nodes or units such as the DU61 and other nodes or units.

[0221] The CU 62 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).

[0222] As described above, the CU62 can be integrated / joined with the DU61 as an integrated / joined unit. Any function in the description of the CU62 can be implemented in the above integrated / joined unit.

[0223] AMF Figure 10 is a block diagram showing the main components of the AMF 70. As shown in the figure, the apparatus includes a transceiver circuit 701 operable to transmit signals to other nodes (including UE3, NSSAAF, etc.) via a network interface 702 and receive signals from other nodes. A control unit 703 controls the operation of the AMF 70 according to software stored in a memory 704. The software may be pre-installed in the memory 704 and / or downloaded, for example, via a telecommunication network or from a removable memory device (RMD). The software includes, among other things, 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 processing (generating / sending / receiving) signaling between the AMF 70 and other nodes such as UE3 (e.g., via (R)AN node 5) and other core network nodes (including core network nodes within the HPLMN of UE3 when UE3 is roaming in). Such signaling can include, for example, appropriately formatted signaling messages (e.g., registration request messages and related response messages) related to access and mobility management procedures (for UE3).

[0224] The AMF 70 can support a non-public network (NPN). The NPN can be a stand-alone non-public network (SNPN) or a public network integrated non-public network (PNI-NPN). The AMF 7001 and AMF 7002 can have the same components as the AMF 70.

[0225] PCF FIG. 11 is a block diagram showing the main components of the PCF 73. As shown, the apparatus includes a transceiver circuit 731 operable to transmit signals to other nodes (including the AMF 70) via a network interface 732 and receive signals from other nodes. A control unit 733 controls the operation of the PCF 73 according to software stored in a memory 734. The software may be pre-installed in the memory 734 and / or downloaded, for example, via a telecommunication network or from a removable data storage device (such as a Removable memory Device: RMD). The software includes, among other things, 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 handling (generating / sending / receiving) signaling between the PCF 73 and other nodes such as the AMF 70 and other core network nodes (including core network nodes within the HPLMN of the UE3 when the UE3 is roaming in). Such signaling can include, for example, appropriately formatted (e.g., using HTTP restful methods of a convenient way based on a service-based interface) signaling messages related to policy management procedures (for the UE3).

[0226] The PCF 73 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). The PCF 7301 and the PCF 7302 can have the same components as the PCF 73.

[0227] AUSF FIG. 12 is a block diagram showing the main components of the AUSF 74. As shown, the apparatus includes a transceiver circuit 741 operable to transmit signals to and receive signals from other nodes (including the UDM 75) via a network interface 742. A control unit 743 controls the operation of the AUSF 74 according to software stored in a memory 744. The software may be pre-installed in the memory 744 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (such as a Removable memory Device: RMD). The software includes, among other things, 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 core network nodes within the HPLMN of the UE3 when the UE3 is roaming in). Such signaling can include, for example, appropriately formatted signaling messages related to policy management procedures (for the UE3), such as a convenient method of HTTP based on a service-based interface).

[0228] The AUSF 74 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).

[0229] UDM Figure 13 is a block diagram showing the main components of the UDM 75. As shown in the figure, the apparatus includes a transceiver circuit 751 operable to transmit signals to other nodes (including the AMF 70) via a network interface 752 and receive signals from other nodes. A control unit 753 controls the operation of the UDM 75 according to software stored in a memory 754. The software may be pre-installed in the memory 754 and / or downloaded, for example, via a telecommunications network or from a removable memory device (RMD). The software includes, among other things, 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 UDM 75 and other nodes such as the AMF 70 and other core network nodes (including core network nodes within the VPLMN of the UE 3) when the UE 3 is roaming out. Such signaling can include, for example, appropriately formatted signaling messages (e.g., a convenient way of HTTP based on a service-based interface) related to mobility management procedures (for the UE 3).

[0230] The UDM 75 can support a non-public network (NPN). The NPN can be a stand-alone non-public network (SNPN) or a public network integrated non-public network (PNI-NPN).

[0231] NSSF FIG. 14 is a block diagram showing the main components of the NSSF 76. As shown, the apparatus includes a transceiver circuit 761 operable to transmit signals to other nodes (including the AMF 70) via a network interface 762 and receive signals from other nodes. A control unit 763 controls the operation of the NSSF 76 according to software stored in a memory 764. The software may be pre-installed in the memory 764 and / or downloaded, for example, via a telecommunication network or from a removable memory device (RMD). The software includes, among other things, an operating system 7641 and a communication control module 7642 having at least a transceiver control module 76421. The communication control module 7642 (using its transceiver control module 76421) is responsible for processing (generating / sending / receiving) signaling between the NSSF 76 and other nodes such as the AMF 70 and other core network nodes (including core network nodes in the VPLMN of the UE3 when the UE3 is roaming out). Such signaling can include, for example, appropriately formatted signaling messages (e.g., in a convenient way of HTTP based on a service-based interface) related to mobility management procedures (for the UE3).

[0232] The NSSF 76 can support a non-public network (NPN). The NPN can be a stand-alone non-public network (SNPN) or a public network integrated non-public network (PNI-NPN).

[0233] All or part of the exemplary aspects disclosed above can be described as follows, but are not limited thereto.

[0234] 5.15.5.2 Selection of Serving AMF Supporting Network Slices 5.15.5.2.1 Registration to a Set of Network Slices When the UE registers with a PLMN via an access type, the UE shall, - have either, or both, the configured NSSAI for this PLMN, - the permitted NSSAI for this PLMN and access type, and The UE shall provide the network with a Requested NSSAI including one or more S-NSSAIs corresponding to the network slice(s) the UE is attempting to register to, in the AS layer and NAS layer under the conditions described in clause 5.15.9, unless the S-NSSAI is stored in the UE's Pending NSSAI.

[0235] The Requested NSSAI shall be - the default configured NSSAI if the UE has neither the configured NSSAI nor the permitted NSSAI for the serving PLMN, - for example, the configured NSSAI or a subset thereof as described below if the UE does not have the permitted NSSAI for the access type of the serving PLMN, - the permitted NSSAI for the access type to which the Requested NSSAI is being sent, or a subset thereof, or - one of the following: the permitted NSSAI for the access type to which the Requested NSSAI is being sent, or a subset thereof, plus one or more S-NSSAIs from the configured NSSAI not yet included in the permitted NSSAI for the access type, as described below. Note 1: If the UE wishes to register only a subset of S-NSSAIs from the configured NSSAI or the permitted NSSAI, for example, so that the UE can register with several network slices to establish PDU sessions for several applications (if any), and if the UE uses URSP rules (including the Network Slice Selection Policy (NSSP)) or UE local configurations defined in clause 6.1.2.2.1 of TS 23.503

[45] , the UE uses the applicable URSP rules or UE local configurations to ensure that the S-NSSAIs included in the Requested NSSAI do not conflict with the URSP rules or UE local configurations.

[0236] The subset of S-NSSAIs within the configured NSSAI provided to the Requested NSSAI consists of one or more S-NSSAIs (if any) from among those one or more S-NSSAIs that exist within the configured NSSAI applicable to this PLMN, and the corresponding S-NSSAIs do not already exist in the allowed NSSAI for the access type of this PLMN. The UE shall not include in the Requested NSSAI any S-NSSAI that is currently rejected by the network (i.e., rejected in the current registration area or rejected by the PLMN). When registering with a PLMN for which neither a configured NSSAI nor an allowed NSSAI applicable to this PLMN exists, the S-NSSAIs provided to the Requested NSSAI correspond to the S-NSSAIs (if any) within the default configured NSSAI, provided that the UE does not have HPLMN S-NSSAIs for the established PDU session(s). In this case, the HPLMN S-NSSAIs (if any) shall be those provided by the mapping of the Requested NSSAI within the NAS registration request message, and there are no corresponding VPLMN S-NSSAIs within the Requested NSSAI. When the UE is provided with NSSRG information together with the configured NSSAI, referring to Section 5.15.12.2, the UE shall include only S-NSSAIs in the Requested NSSAI that share a common NSSRG.

[0237] When the UE registers with a PLMN via an access type and the Requested NSSAI is based on the default configured NSSAI, the UE shall also indicate so in the registration request message.

[0238] The UE shall include the Requested NSSAI in the RRC connection establishment and the establishment of the connection to the N3IWF / TNGF (if applicable), and in the NAS registration procedure messages that comply with the conditions described in clause 5.15.9. However, the UE shall not indicate any NSSAI in the RRC connection establishment message or the initial NAS message unless it has either the configured NSSAI for the corresponding PLMN, the permitted NSSAI for the corresponding PLMN and access type, or the default configured NSSAI. If the UE has the HPLMN S-NSSAI(s) for the established PDU session(s), the HPLMN S-NSSAI(s) shall be provided in the mapping of the Requested NSSAI in the NAS registration request message, regardless of whether the UE has the corresponding VPLMN S-NSSAI. The (R)AN shall route the NAS signaling between this UE and the AMF selected using the Requested NSSAI obtained during the RRC connection establishment or the connection to the N3IWF / TNGF. If the (R)AN cannot select an AMF based on the Requested NSSAI, it shall route the NAS signaling to the AMF from the set of default AMFs. In the NAS signaling, if available, the UE shall provide the mapping of each S-NSSAI of the Requested NSSAI to the corresponding HPLMN S-NSSAI.

[0239] When the UE registers with a PLMN, if for this PLMN neither the Requested NSSAI nor the GUAMI is included while the UE is establishing a connection to the (R)AN, the (R)AN shall route all NAS signaling to / from this UE to / from the default AMF. When receiving the Requested NSSAI and the 5G-S-TMSI or GUAMI from the UE during RRC connection establishment or establishment of a connection to the N3IWF / TNGF, if the 5G-AN can reach the AMF corresponding to the 5G-S-TMSI or GUAMI, the 5G-AN shall forward the request to this AMF. Otherwise, the 5G-AN shall select an appropriate AMF based on the Requested NSSAI provided by the UE and forward the request to the selected AMF. If the 5G-AN cannot select an AMF based on the Requested NSSAI, the request shall be sent to the default AMF.

[0240] When the AMF selected by the AN during the registration procedure receives the UE registration request, or after AMF selection by the MME (i.e., during handover from EPS to 5GS), the AMF receives S-NSSAI(s) from the SMF+PGW-C in the 5GC. -As part of the registration procedure described in clause 4.2.2.2.2 of TS 23.502 [3], or as part of the handover from EPS to 5GS using the N26 interface procedure described in clause 4.11.1.2.2 of TS 23.502 [3], the AMF can execute a query to the UDM to obtain UE subscription information including the subscribed S-NSSAI. -The AMF verifies whether the S-NSSAI(s) within the Requested NSSAI, or the S-NSSAI(s) received from the SMF+PGW-C, are permitted based on the subscribed S-NSSAI (to identify the subscribed S-NSSAI, the AMF can use the mapping to the HPLMN S-NSSAI provided in the NAS message by the UE for each S-NSSAI of the Requested NSSAI). - If the UE context in the AMF does not yet contain the allowed NSSAI for the corresponding access type, the AMF executes a query to the Network Slice Selection Function (NSSF) (see (B) below for subsequent processing), except when the AMF is permitted to determine whether it can serve the UE based on the settings within this AMF (see (A) below for subsequent processing). The IP address or Fully Qualified Domain Name (FQDN) of the NSSF is set locally within the AMF. Note 2: The settings within the AMF depend on the operator's policy. - If the UE context in the AMF already contains the allowed NSSAI for the corresponding access type, based on the settings of this AMF, the AMF is permitted to determine whether it can serve the UE (see (A) below for subsequent processing). - The AMF or NSSF may optionally have previously subscribed to network data analytics related to slice load levels and / or observed service experiences and / or distributed analytics for a region of interest composed of one or more TAIs with respect to network slices from the NWDAF. If the AMF subscribes to the analytics, the AMF may determine that it cannot serve the UE based on the received analytics (see (A) below). If the AMF subscribes to notifications regarding changes in the availability information of a network slice or network slice instance from the NSSF that optionally indicates a list of supported TAIs, it may determine that it cannot serve the UE after receiving a restriction notification (see (A) below). If the AMF has not subscribed to notifications regarding changes in the availability information from the NSSF, the NSSF can take into account the analysis information when the AMF executes a query to the NSSF (see (B) below). Note 3: The settings within the AMF depend on the operator's policy.

[0241] (A) Depending on the realization of the above settings, the AMF can determine whether it can serve the UE, and the following is executed. - In the case of mobility from EPS to 5GS, the AMF first derives the serving PLMN value(s) of the S-NSSAI(s) based on the HPLMN S-NSSAI(s) in the mapping of the Requested NSSAI (in CM-IDLE state) or the HPLMN S-NSSAI(s) received from the SMF + PGW-C (in CM-CONNECTED state). Then, the AMF regards the derived value(s) as the Requested NSSAI. - Within the PLMN in 5GC mobility, the new AMF derives the serving PLMN value(s) of the S-NSSAI(s) based on the HPLMN S-NSSAI(s) in the mapping of the Requested NSSAI. Then, the AMF regards the derived value(s) as the Requested NSSAI. - The AMF checks whether it can serve all the S-NSSAI(s) from the Requested NSSAI present in the subscribed S-NSSAI (with the possibility of using the settings for mapping the S-NSSAI value between the HPLMN and the serving PLMN), or, if the Requested NSSAI is not provided, or if none of the S-NSSAI(s) in the Requested NSSAI is permitted, that is, if it does not match any of the subscribed S-NSSAI(s), or if it is not available in the current UE's tracking area, whether it can serve all the S-NSSAI(s) marked as default in the subscribed S-NSSAI (see Clause 5.15.3). - If the AMF subscribes to network data analytics related to the slice load level of network slices from the NWDAF and / or the observed service experience and / or distributed analytics, or if the AMF receives network slice restrictions from the NSSF applicable to the list of TAIs supported by the AMF, the AMF can use that information to determine whether it can serve the UE on the S-NSSAI(s) within the Requested NSSAI. - If the AMF can serve the S-NSSAI within the Requested NSSAI, the AMF remains the serving AMF for the UE. The allowed NSSAI then consists of a list of S-NSSAI(s) within the Requested NSSAI allowed based on the subscribed S-NSSAI, and / or a list of S-NSSAI(s) for the serving PLMN mapped to the HPLMN S-NSSAI(s) provided by the mapping of the Requested NSSAI based on the subscribed S-NSSAI, or, if neither the Requested NSSAI nor the mapping of the Requested NSSAI is provided, or if none of the S-NSSAI within the Requested NSSAI is allowed, all subscribed S-NSSAI(s) marked as default within the subscribed S-NSSAI, and, in addition to any network slice instance restrictions for the S-NSSAI(s) within the allowed NSSAI provided by the NSSF, all subscribed S-NSSAI taking into account the availability of the network slice instances described in clause 5.15.8 that can serve the S-NSSAI(s) within the allowed NSSAI within the current tracking area of the UE. If the AMF receives the NSSRG information of the subscribed S-NSSAI as part of the UE subscription information, the AMF shall consider only those that include the allowed NSSAI S-NSSAI, all sharing a common NSSRG (see clause 5.15.12). If at least one S-NSSAI within the Requested NSSAI is not available in the current tracking area of the UE, the AMF determines the target NSSAI or step (B) is executed. The AMF also determines the mapping if the S-NSSAI(s) included in the allowed NSSAI need to be mapped to the subscribed S-NSSAI(s) value.If the Requested NSSAI is not provided, or if the mapping of the S-NSSAI within the Requested NSSAI to the HPLMN S-NSSAI is incorrect, or if the Requested NSSAI contains an S-NSSAI that is not valid in the serving PLMN, or if the UE indicates that the Requested NSSAI is based on the default configured NSSAI, the AMF may, based on the subscribed S-NSSAI(s) and operator configuration, also determine the configured NSSAI for the serving PLMN and, if applicable, the relevant mapping of the configured NSSAI to the HPLMN S-NSSAI, so that these can be configured in the UE. Next, step (C) is executed. - Otherwise, the AMF executes a query to the NSSF (see (B) below).

[0242] (B) If necessary as described above, the AMF needs to execute a query to the NSSF and the following is performed. - The AMF executes a query to the NSSF using the Requested NSSAI, Pending NSSAI (when the UE is in the CM-IDLE state, the pending NSSAI consists of the S-NSSAI received in the requested NSSAI that is subject to NSSAA. When the UE is in the CM-CONNECTED state, the pending NSSAI consists of any pending S-NSSAI stored in the AMF and any new S-NSSAI received in the requested NSSAI of the registration request message received in the CM-CONNECTED state, where the S-NSSAI is subject to NSSAA), default configured NSSAI indication, mapping of the Requested NSSAI to the HPLMN S-NSSAI, subscribed S-NSSAI (displayed with indication if marked as default S-NSSAI), NSSRG information (see clause 5.15.12 if provided by the UDM), any permitted NSSAI for other access types (including mapping to the HPLMN S-NSSAI), PLMN ID of the SUPI, and the UE's current tracking area. - Based on this information, local settings, and other locally available information including the RAN capabilities within the current tracking area of the UE, or the load level information of the network slice instance provided by the NWDAF, the NSSF performs the following. - In the mapping of the Requested NSSAI to the HPLMN S-NSSAI, verify which S-NSSAI(s) within the Requested NSSAI are permitted based on comparing the subscribed S-NSSAI with the S-NSSAI. If the Requested NSSAI is not provided, or if the S-NSSAI from the Requested NSSAI is not permitted, i.e., does not exist within the subscribed S-NSSAI or is not available, for example, in the current tracking area of the UE, consider the S-NSSAI(s) marked as default within the subscribed S-NSSAI. If NSSRG information is provided, the NSSF selects only the S-NSSAI that shares a common NSSRG (see clause 5.15.12). - If the AMF has not subscribed to notifications regarding changes in the availability information of network slices or network slice instances from the NSSF, and the NSSF has subscribed to network data analytics related to the slice load level and / or observed service experience and / or distributed analytics of network slices from the NWDAF, the NSSF can use the analysis information to determine a list of S-NSSAI(s) within the (network slice instance(s) and) permitted NSSAI(s) to serve the UE. - Select one or more network slice instances to serve the UE. If multiple network slice instances within the UE's tracking area can serve a given S-NSSAI, the NSSF can, based on the operator's configuration, select one of them to serve the UE, or the NSSF can defer the selection of the network slice instance until an NF / service within the network slice instance needs to be selected. - Determine the set of target AMFs to be used to serve the UE, or a list of candidate AMFs (if any), perhaps after querying the NRF based on the configuration. Note 4: If the target AMF(s) returned from the NSSF is a list of candidate AMF(s), the registration request message can only be redirected via direct signaling between the initial AMF and the selected target AMF, as described in clause 5.15.5.2.3. The NSSF does not provide the target AMF(s) when providing the target NSSAI to redirect or hand over the UE to a cell in another TA, as described in clause 5.3.4.3.3. - Determine the permitted NSSAI(s) for the applicable access type(s), which consists of a list of S-NSSAI(s) within the Requested NSSAI permitted based on the subscribed S-NSSAI, and / or a list of S-NSSAI(s) for the serving PLMN mapped to the HPLMN S-NSSAI provided by the mapping of the Requested NSSAI permitted based on the subscribed S-NSSAI, or, if neither the Requested NSSAI nor the mapping of the Requested NSSAI is provided, or if none of the S-NSSAI within the Requested NSSAI are permitted, all S-NSSAI(s) marked as default within the subscribed S-NSSAI and all S-NSSAI that can serve the S-NSSAI(s) within the permitted NSSAI within the current UE's tracking area, taking into account the availability of the network slice instances described in clause 5.15.8. If NSSRG information is applied, the NSSF shall select only the S-NSSAI that share a common NSSRG (see section 5.15.12). - Optionally, also determine the mapping of each S-NSSAI of the permitted NSSAI to the subscribed S-NSSAI(s). - Based on the operator configuration, the NSSF may determine the Network Repository Function(s) (NRF) to be used to select the Network Function(s) (NF) / services within the selected network slice instance(s). - Additional processing to determine the mapping to the permitted NSSAI(s) and the subscribed S-NSSAI in a roaming scenario, as described in clause 5.15.6. - If the Requested NSSAI and the pending NSSAI are not provided, or if the Requested NSSAI or the pending NSSAI contains an S-NSSAI that is not valid in the serving PLMN, or if the mapping of the S-NSSAI in the Requested NSSAI to the HPLMN S-NSSAI is incorrect, or if the default configured NSSAI indication is received from the AMF, the NSSF, based on the subscribed S-NSSAI(s) and the operator configuration, may also determine the configured NSSAI for the serving PLMN and, if applicable, the associated mapping of the configured NSSAI to the HPLMN S-NSSAI, so that these can be configured in the UE. - If at least one S-NSSAI within the Requested NSSAI or the pending NSSAI is not available in the current UE's tracking area, the NSSF may provide a target NSSAI for the purpose of enabling the NG-RAN to redirect the UE to a cell in another frequency band's TA that supports a network slice not available in the current TA, as described in clause 5.3.4.3.3. - If the S-NSSAI within the pending NSSAI is not supported in the TA or is not available in the PLMN, the NSSF includes the S-NSSAI in the rejected NSSAI, along with the reason that the S-NSSAI is not supported in the TA or the S-NSSAI is not supported in the PLMN. - The NSSF returns to the current AMF the permitted NSSAI for the applicable access type, the mapping of each S-NSSAI of the permitted NSSAI to subscribed S-NSSAI if determined, and a list of candidate AMF(s) based on the target AMF set or configuration. The NSSF can return the NRF used to select NF / services within the selected network slice instance(s), and the NRF(s) used to determine a list of candidate AMF(s) from the AMF set. The NSSF can return the NSI ID(s) associated with the network slice instance(s) corresponding to a particular S-NSSAI. The NSSF can return the rejected S-NSSAI(s) as described in clause 5.15.4.1. The NSSF can return the configured NSSAI for the serving PLMN and the associated mapping of the configured NSSAI to the HPLMN S-NSSAI. The NSSF can return the target NSSAI as described in clause 5.3.4.3.3. - Depending on the available information and based on the configuration, the AMF can query an appropriate (e.g., pre-configured locally or provided by the NSSF) NRF using the target AMF set. The NRF returns a list of candidate AMF. - If an AMF reallocation is required, the current AMF routes the registration request or transfers the UE context to the target serving AMF as described in clause 5.15.5.2.3. - Execute step (C).

[0243] (C) The serving AMF determines the registration area such that all S-NSSAIs of the permitted NSSAI for this registration area become available in all tracking areas of the registration area (also considering other aspects as described in clause 5.3.2.3), and then returns to the UE this permitted NSSAI and, if provided, the mapping of the permitted NSSAI to the subscribed S-NSSAI. The AMF can return a reject S-NSSAI(s) as described in clause 5.15.4.1. Note 5: The S-NSSAIs within the permitted NSSAI for non-3GPP access are uniformly available in the PLMN in the case of N3IWF. For other types of non-3GPP access, the S-NSSAIs within the permitted NSSAI for non-3GPP access may not be uniformly available across the PLMN. For example, different wireline access gateway functions (W-AGFs) can support different tracking area identities (TAIs) that support different network slices.

[0244] If the Requested NSSAI is not included, or the mapping of the S-NSSAI within the Requested NSSAI to the HPLMN S-NSSAI is incorrect, or the Requested NSSAI is not considered valid within the PLMN and thus at least one S-NSSAI within the Requested NSSAI is rejected as not being usable by the UE within the PLMN, or the UE indicates that the Requested NSSAI is based on the default configured NSSAI, the AMF can update the UE slice configuration information of the PLMN as described in clause 5.15.4.2.

[0245] If the Requested NSSAI does not include an S-NSSAI that maps to the S-NSSAI of the HPLMN for which the network slice specific authentication and authorization are applicable, and the AMF determines that it cannot provide the S-NSSAI to the permitted NSSAI of the UE within the current tracking area of the UE, and cannot add the default S-NSSAI(s) as described in step (A), the AMF shall reject the UE registration and include the list of rejected S-NSSAI in the rejection message, each of which shall have an appropriate rejection cause value.

[0246] If the Requested NSSAI includes an S-NSSAI that maps to the S-NSSAI of the HPLMN for which the network slice specific authentication and authorization are applicable, the AMF shall include in the registration acceptance message the permitted NSSAI that includes only the S-NSSAI that is not subject to the network slice specific authentication and authorization, and, based on the UE context within the AMF, if any, the S-NSSAI for which the network slice specific authentication and authorization for at least one of the corresponding HPLMN S-NSSAI has been previously successful, regardless of the access type.

[0247] The AMF shall also provide a list of rejected S-NSSAI, each S-NSSAI having an appropriate rejection cause value. If the pending S-NSSAI is rejected by the NSSF, the AMF may interrupt the ongoing NSSAA procedure.

[0248] If the AMF determines the target NSSAI or receives the target NSSAI from the NSSF, the AMF shall provide the target NSSAI to the Policy Control Function (PCF) to obtain the corresponding RFSP as described in clause 5.3.4.3.1, or if the PCF is not deployed, the AMF shall determine the corresponding RFSP based on the local configuration. Then, the AMF shall provide the target NSSAI and the corresponding RFSP to the NG-RAN as described in clause 5.3.4.3.3. If the S-NSSAI mapping to the S-NSSAI of the HPLMN according to the network slice specific authentication and authorization is in progress, it shall be in the "pending" state in the AMF and included in the Pending NSSAI. The Pending NSSAI may include, if applicable, the mapping of the S-NSSAI(s) for the serving PLMN to the HPLMN S-NSSAI. The UE shall not include any S-NSSAI from the Pending NSSAI stored by the UE in the Requested NSSAI, regardless of the access type.

[0249] If: - all S-NSSAI(s) within the Requested NSSAI are still subject to network slice specific authentication and authorization, or - the Requested NSSAI is not provided, or none of the S-NSSAI within the Requested NSSAI matches any of the subscribed S-NSSAI and all S-NSSAI(s) marked as default within the subscribed S-NSSAI are subject to network slice specific authentication and authorization, The AMF shall provide the UE with an "NSSAA to be executed" indicator in the registration acceptance message and not provide the permitted NSSAI. When receiving the registration acceptance message, the UE shall register with the PLMN, but until the UE receives the permitted NSSAI, it shall wait for the completion of network slice-specific authentication and authorization without attempting to use any services provided by the PLMN for any access, except for emergency services (see TS 24.501

[47] ).

[0250] Next, the AMF shall start the network slice-specific authentication and authorization procedures for each S-NSSAI that requires it, as described in clause 5.15.10, except for S-NSSAIs for which network slice-specific authentication and authorization has already been started for another access type of the same S-NSSAI(s) based on the network policy. At the end of the network slice-specific authentication and authorization steps, the AMF shall provide the UE with a new permitted NSSAI that also includes the S-NSSAI for which network slice-specific authentication and authorization was successful, by means of a UE configuration update procedure. The AMF may execute an AMF selection when the NSSAA is completed for the S-NSSAI targeted by the S-NSSAI in the "pending" status. If an AMF change is required, this shall be triggered by the AMF using a UE configuration update procedure indicating that UE re-registration is necessary. S-NSSAIs that have not been successfully authenticated and authorized shall not be included in the permitted NSSAI and shall be included in a list of rejected S-NSSAIs with a rejection cause value indicating the failure of network slice-specific authentication and authorization.

[0251] After the network slice specific (re)authentication and (re)authorization procedures are completed, if the AMF determines that it cannot provide the S-NSSAI to the permitted NSSAI of a UE that has already been authenticated and authorized by the PLMN and cannot add default S-NSSAI(s) as described in step (A), the AMF shall execute the deregistration procedure initiated by the network as described in clause 4.2.2.3.3 of TS 23.502 [3], and include the list of rejected S-NSSAI in the explicit deregistration request message, each of which shall have an appropriate rejection cause value.

[0252] If the S-NSSAI is rejected with a rejection cause value indicating a failure or invalidation of network slice specific authentication and authorization, the UE may retry the S-NSSAI request based on a local policy within the UE.

[0253] 5.15.5.2.2 Change of the set of network slice(s) for the UE The set of network slices for the UE may be changed at any time while the UE is registered with the network and may be initiated by the network or by the UE under certain conditions as described below.

[0254] The network can change the set of network slice(s) to which the UE is registered based on local policy, subscription changes and / or UE mobility and / or UE distributed data classification, operational reasons (e.g., the network slice instance is no longer available, or the load level information or service experience of the network slice or network slice instance provided by the Network Data Analytics Function (NWDAF) is no longer available), and provide the UE with a new registration area and / or permitted NSSAI and the mapping of this permitted NSSAI to the HPLMN S-NSSAI for each access type to which the UE is registered. Further, the network can provide the configured NSSAI for the serving PLMN, related mapping information, and the rejected S-NSSAI. The network can perform such changes via each access type during the registration procedure or trigger the UE to be notified of the network slice change using the UE configuration update procedure as specified in clause 4.2.4 of TS 23.502 [3]. The new permitted NSSAI(s) and the mapping to the HPLMN S-NSSAI are determined as described in clause 5.15.5.2.1 (AMF reallocation may be required). The AMF provides the UE with - an indication that a confirmation response from the UE is required, - the configured NSSAI for the serving PLMN (if required), the rejected S-NSSAI(s) (if required), and the TAI list, and - a new permitted NSSAI (if applicable) with the related mapping of the permitted NSSAI for each access type, except when the AMF cannot determine a new permitted NSSAI (e.g., all S-NSSAIs within the old permitted NSSAI have been removed from the subscribed S-NSSAI).

[0255] Furthermore, - If the changes to the permitted NSSAI affect their existing connections to network slices (e.g., the new S-NSSAI requires a separate AMF that cannot be determined by the current serving AMF, or the AMF cannot determine the permitted NSSAI), or if the UE is required to immediately execute the registration procedure due to the AMF local policy even if the changes do not affect the existing connections to network slices, - The serving AMF indicates to the UE the need to execute the registration procedure without including the Globally Unique AMF Identifier (GUAMI) or 5G-S-TMSI in the access stratum signaling after entering the CM-IDLE state. The AMF shall release the NAS signaling connection to the UE in order to enter CM-IDLE after receiving the confirmation response from the UE. - When the UE receives an indication to execute the registration procedure without including the GUAMI or 5G-S-TMSI in the access stratum signaling after entering the CM-IDLE state, then, - The UE deletes the stored (old) permitted NSSAI and related mappings, and any (old) rejected S-NSSAI. - The UE shall start the registration procedure using the registration type mobility registration update as described in step 4 of subclause 4.2.4.2 of TS 23.502 [3] after the UE enters the CM-IDLE state. The UE shall include the Requested NSSAI in the registration request message together with the related mapping of the Requested NSSAI. Also, the UE shall include the Requested NSSAI in the access stratum signaling according to the conditions described in subclause 5.15.9, but shall not include the GUAMI.

[0256] If there is an established PDU session(s) associated with the emergency service, the serving AMF indicates to the UE the need to perform the registration procedure, but does not release the NAS signaling connection to the UE. The UE performs the registration procedure only after the release of the PDU session(s) used for the emergency service.

[0257] In addition to sending the new allowed NSSAI to the UE, the following applies when the UE can no longer use the network slice(s) used for one or more PDU sessions. - If the network slice is no longer available under the same AMF (e.g., due to a UE subscription change), the AMF indicates to the SMF(s) that the PDU session ID(s) corresponding to the related S-NSSAI should be released. The SMF releases the PDU session in accordance with subclause 4.3.4.2 of TS 23.502 [3]. - If the network slice is no longer available when the AMF changes (e.g., due to a change in the registration area), the new AMF indicates to the old AMF that the PDU session(s) corresponding to the related S-NSSAI should be released. The old AMF notifies the corresponding SMF(s) to release the indicated PDU session(s). The SMF(s) releases the PDU session(s) as described in subclause 4.3.4 of TS 23.502 [3]. The new AMF then changes the PDU session status accordingly. The PDU session(s) context is locally released at the UE after receiving the PDU session status in the registration acceptance message.

[0258] The UE uses either the URSP rules (including NSSP) or any of the UE local configurations defined in clause 6.1.2.2.1 of TS 23.503

[45] to determine whether it can route ongoing traffic via an existing PDU session belonging to another network slice or to establish a new PDU session(s) associated with the same / another network slice.

[0259] To change the set of S-NSSAIs for which the UE is registered via an access type, the UE shall initiate the registration procedure via this access type as specified in clause 5.15.5.2.1. If, for an established PDU session, - none of the HPLMN S-NSSAI values in the mapping of the Requested NSSAI to the HPLMN S-NSSAI included in the registration request match the HPLMN S-NSSAI associated with the PDU session, or - none of the S-NSSAI values within the Requested NSSAI match the value of the HPLMN S-NSSAI associated with the PDU session and the mapping of the Requested NSSAI to the HPLMN S-NSSAI is not included in the registration request, the network shall release this PDU session as follows. - The AMF shall notify the corresponding SMF(s) to release the indicated PDU session(s). The SMF(s) shall release the PDU session(s) as described in clause 4.3.4 of TS 23.502 [3]. The AMF shall then change the PDU session status accordingly. The PDU session(s) context shall be locally released at the UE after receiving the PDU session status from the AMF.

[0260] A change to the set of S-NSSAIs registered for a UE (whether initiated by the UE or the network) may lead to an AMF change according to the operator policy, as described in clause 5.15.5.2.1.

[0261] 5.15.5.2.3 AMF Reallocation Due to Support of Network Slice(s) During the registration procedure in a PLMN, if the network decides that the UE should be served by a different AMF based on the network slice(s) aspect, the AMF that first receives the registration request shall redirect the registration request to the target AMF via the 5G Access Network (5G-AN) or via direct signaling between the initial AMF and the target AMF. If the target AMF(s) is / are returned from the NSSF and identified by a list of candidate AMF(s), the redirect message shall be sent only via direct signaling between the initial AMF and the target AMF. If the redirect message is sent by the AMF via the 5G-AN, the message shall include information for selecting the new AMF to serve the UE.

[0262] During the registration procedure, if the UE requests a new S-NSSAI that is not supported in the UE's current tracking area, the serving AMF itself or by interacting with the NSSF as described in clause 5.15.5.2.1 can determine the target NSSAI. The AMF provides the target NSSAI to the NG-RAN, and the NG-RAN can apply redirection or handover of the UE to a cell within another TA that supports the target NSSAI, as described in clause 5.3.4.3.3.

[0263] During the handover from EPS to 5GS using the N26 interface procedure, if the network determines that the UE should be served by different AMFs based on the network slice(s) aspect, the AMF that receives the forward transfer request from the MME shall transfer the UE context to the target AMF via direct signaling between the initial AMF and the target AMF as described in Subclause 4.11.1.2.2 of TS 23.502 [3].

[0264] For an already registered UE, the system shall support the redirection initiated by the UE's network from its serving AMF to the target AMF due to considerations of network slice(s) (e.g., the operator has changed the mapping between network slice instances and their respective serving AMF(s)). The operator policy determines whether redirection between AMFs is permitted.

[0265] 4.2.2.2.3 Registration of AMF Reallocation When the AMF receives a registration request, the AMF may need to route the registration request to another AMF, for example, if the initial AMF is not the appropriate AMF to serve the UE. The registration procedure by AMF reallocation described in Figure 15 (Figure 4.2.2.2.3-1) is used to route the UE's NAS message to the target AMF during the registration procedure.

[0266] The initial AMF and the target AMF register their capabilities with the NRF.

[0267] 1. When the UE is in the CM-IDLE state, steps 1 and 2 in Figure 4.2.2.2.2-1 exist, and the (R)AN sends the registration request message in the initial UE message to the initial AMF. When the UE is in the CM-CONNECTED state and triggers the registration procedure, the NG-RAN sends the registration request message in the uplink NAS transport message to the serving AMF, which is the initial AMF. The AMF can skip step 2-3.

[0268] 2. If the AMF needs the Subscription Permanent Identifier (SUPI) and / or the UE's subscription information to determine whether to route the registration request, or if the registration request is not sent with integrity protection or it is indicated that the integrity protection has failed, the AMF executes steps 4 to 9a or 9b in Figure 4.2.2.2.2-1.

[0269] 3a. [Condition] If the initial AMF needs the UE's subscription information to determine whether to route the registration request and the UE's slice selection subscription information is not provided by the old AMF, as described in clause 6.3.8 of TS 23.501 [2], the AMF selects the Unified Data Management (UDM).

[0270] 3b. From the initial AMF to the UDM: Nudm_SDM_Get(SUPI, slice selection reservation data).

[0271] The initial AMF requests the UE's slice selection reservation data from the UDM by invoking the Nudm_SDM_Get (see clause 5.2.3.3.1) service operation. The UDM may obtain this information from the Unified Data Repository (UDR) by Nudr_DM_Query(SUPI, slice selection reservation data).

[0272] In the case of disaster roaming registration, the AMF can provide the UDM with the display of the disaster roaming service.

[0273] 3c. Response from the UDM to the initial AMF: Nudm_SDM_Get. The AMF obtains slice selection subscription data including the subscribed S-NSSAI.

[0274] The UDM responds to the initial AMF with the slice selection subscription data.

[0275] In the case of disaster roaming registration, the UDM responds to the initial AMF with the slice selection subscription data of the disaster roaming service based on the local policy and / or local configuration as specified in clause 5.40.4 of TS 23.501 [2].

[0276] 4a. [Condition] From the initial AMF to the NSSF: Nnssf_NSSelection_Get (Requested NSSAI, [Mapping of Requested NSSAI], Pending NSSAI, optionally [Mapping of Pending NSSAI], subscribed S-NSSAI (multiple possible) with the default S-NSSAI display, [NSSRG information], TAI, permitted NSSAI of other access types (if any), [Mapping of permitted NSSAI], Pending NSSAI of other access types, optionally [Mapping of Pending NSSAI], PLMN ID of the SUPI).

[0277] When a slice selection is required (see clause 5.15.5.2.1 of TS 23.501 [2]), for example, when the initial AMF is not able to serve all S-NSSAI(s) from the Requested NSSAI permitted by the subscription information, the initial AMF shall call the Nnssf_NSSelection_Get service operation from the NSSF by including the Requested NSSAI, optionally the mapping of the Requested NSSAI, the subscribed S-NSSAI with the default S-NSSAI presentation, [NSSRG information], the permitted NSSAI of other access types (if any), the mapping of the permitted NSSAI, the PLMN ID of the SUPI, and the TAI of the UE.

[0278] The AMF shall include, if available, the NSSRG information for the S-NSSAI of the HPLMN as defined in clause 5.15.12 of TS 23.501 [2], which includes information on whether the UE indicates support for subscription-based restrictions on simultaneous registration of network slices and whether the UDM indicates support for providing all subscribed S-NSSAI for the UE.

[0279] 4b. [Condition] Response from the NSSF to the initial AMF for Nnssf_NSSelection_Get (set or list of AMF addresses, permitted NSSAI of the first access type, [mapping of permitted NSSAI], [permitted NSSAI of the second access type], [mapping of permitted NSSAI], [NSI ID(s)], [NRF(s)], [list of rejection reasons (S-NSSAI(s), cause value(s))], [configured NSSAI for the serving PLMN], [mapping of configured NSSAI]).

[0280] The NSSF performs the steps specified in point (B) of clause 5.15.5.2.1 of TS 23.501 [2]. The NSSF returns to the initial AMF the allowed NSSAI for the first access type, optionally the mapping of the allowed NSSAI, the pending NSSAI, optionally [the mapping of the pending NSSAI], the allowed NSSAI for the second access type (if any), optionally the mapping of the allowed NSSAI, the pending NSSAI for the second access type, optionally [the mapping of the pending NSSAI for the second access type], and a list of candidate AMF(s) based on the target AMF set or configuration. The NSSF can return the NSI ID(s) associated with the network slice instance(s) corresponding to the specific S-NSSAI(s). The NSSF can return the NRF(s) used to select the NF / service within the selected network slice instance(s). It can also return information on the rejection cause for the S-NSSAI(s) not included in the allowed NSSAI. The NSSF can return the configured NSSAI for the serving PLMN and, optionally, the associated mapping of the configured NSSAI. If NSSRG information was included in the request, the NSSF provides the configured NSSAI as described in clause 5.15.12 of TS 23.501 [2].

[0281] Note 1: If any, the NRF(s) returned by the NSSF belong to the NRF at any level according to the operator's deployment decision (see clause 6.2.6 of TS 23.501 [2]).

[0282] 5. [Condition] Initial AMF to old AMF: Namf_Communication_RegistrationStatusUpdate (failure cause).

[0283] If the UE is in CM-IDLE and a different AMF is selected, the initial AMF sends a rejection indication to the old AMF indicating that the UE registration procedure did not complete fully at the initial AMF. The old AMF continues as if it had never received Namf_Communication_UEContextTransfer.

[0284] 6a. [Condition] From the initial AMF to the NRF: Nnrf_NFDiscovery_Request (NF type, AMF set).

[0285] If the initial AMF does not locally store the target AMF address and either the initial AMF intends to use a direct reroute to the target AMF or the reroute via the (NG-R)AN message needs to include the AMF address, the initial AMF calls the Nnrf_NFDiscovery_Request service operation from the NRF to discover a suitable target AMF having the NF capabilities required to serve the UE. The NF type is set to AMF. The AMF set is included in the Nnrf_NFDiscovery_Request.

[0286] 6b. [Condition] Response from the NRF to the AMF: Nnrf_NFDiscovery_Request (list of (AMF pointer, AMF address, and additional selection rules and NF capabilities)).

[0287] The NRF responds with a list of potential target AMF(s). The NRF can also provide details of the services offered by the candidate AMF(s), if available, together with the notification endpoints of the notification services for each type registered by the selected AMF with the NRF. Alternatively, a list of potential target AMF and their capabilities, and optionally additional selection rules, is provided. Based on the information about the registered NFs and the required capabilities, the target AMF is selected by the initial AMF.

[0288] If a security association is established between the UE and the initial AMF, to avoid registration failure, the initial AMF transfers the NAS message to the target AMF by executing step 7(A).

[0289] Note 2: When the initial AMF transfers the NAS message to the target AMF via the (R)AN, the security context in the initial AMF is not transferred to the target AMF. In this case, since the security context in the UE and the target AMF are not synchronized, the UE rejects the NAS message sent from the target AMF.

[0290] Note 3: If AMF reallocation is executed by step 7(A), complete network slice separation cannot be maintained.

[0291] If the initial AMF is not part of the target AMF set and cannot obtain a list of candidate AMF(s) by querying the NRF in the target AMF set (for example, the locally pre-configured NRF on the AMF does not provide the requested information, the query to the appropriate NRF provided by the NSSF is unsuccessful, or the initial AMF has knowledge such that the initial AMF is not permitted as a serving AMF), unless a security association is established between the UE and the initial AMF, the initial AMF transfers the NAS message to the target AMF via the (R)AN that executes step 7(B), and includes the permitted NSSAI and the AMF set so that the AN can select the target AMF as described in subclause 6.3.5 of (R)TS 23.501 [2].

[0292] 7(A): If the initial AMF decides to directly transfer the NAS message to the target AMF based on the local policy and subscription information, the initial AMF calls Namf_Communication_N1MessageNotify for the target AMF to carry the routed NAS message. The Namf_Communication_N1MessageNotify service operation includes AN access information (e.g., information that enables the (R)AN to identify the N2 endpoint, CAG identifier(s) of the CAG cell(s)), and the complete registration request message in clear text, and if available, the UE's SUPI and MM Context, as specified in TS 33.501

[15] . As explained in step 4b, if the initial AMF obtains information from the NSSF, that information is included except for the list of AMF sets or AMF addresses. Then, in step 8, the target AMF updates the (R)AN with the UE's new updated N2 endpoint in the first message from the target AMF to the RAN.

[0293] 7(B). [Condition] If the UE was in CM-IDLE and the initial AMF decides to transfer the NAS message to the target AMF(s) via the (R)AN based on the local policy and subscription information, unless the target AMF is returned by the NSSF and identified by the list of candidate AMF(s), the initial AMF sends an NGAP Reroute Request NAS message to the (R)AN (step 7a). The NGAP Reroute Request NAS message includes information about the target AMF and the complete Registration Request message. As explained in step 4b, if the initial AMF obtains information, that information is included. The (R)AN sends an initial UE message indicating a slice-based reroute, including the information from step 4b provided by the NSSF, to the target AMF (step 7b).

[0294] Editor's Note: Whether the UE in CM-CONNECTED mode step 7(B) also applies is FFS.

[0295] 8. After receiving the registration request message sent in step 7(A)a or step 7(B)b, the target AMF continues the registration procedure from steps 4 to 22 in Figure 4.2.2.2.2-1 (the target AMF corresponds to the new AMF), which includes the UE context obtained from the old AMF. If the 5G security context is received from the initial AMF, the target AMF continues to use that security context instead of the 5G security context that the target AMF might have obtained from the old AMF. If the initial AMF decides to forward the NAS message to the target AMF (step 7(A)), the first message from the target AMF to the (R)AN (either the initial context setup request or the downlink NAS transport) includes the AMF name of the initial AMF and the target AMF UE NGAP ID.

[0296] Modifications and Alternatives The above has been described in detail. As will be understood by those skilled in the art, several modifications and alternatives can be made to the above aspects while benefiting from the disclosure embodied herein. By way of example, only some of these alternatives and modifications are described here. In the above description, for ease of understanding, the UE3 and the network device have been described as having several individual modules (such as a communication control module). These modules can be provided in this way for specific applications, for example, when an existing system is modified to implement the present disclosure, but for other applications, for example, in a system designed from the beginning with the features of the present invention in mind, these modules may not be identifiable as individual entities because they can be incorporated into the overall operating system or code. These modules may be implemented in software, hardware, firmware, or a combination thereof.

[0297] Each controller may include a processing circuit in any suitable form, such as (but not limited to) one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (I / O) circuits, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control buses, data buses, and / or address buses), direct memory access (DMA) functions, hardware or software-implemented counters, pointers, and / or timers, etc.

[0298] In the above aspects, a number of software modules have been described. As would be understood by those skilled in the art, the software modules may be provided in compiled or non-compiled form, and may be supplied to UE3 and network devices as signals via a computer network or on a recording medium. Further, the functions implemented by some or all of this software may be implemented using one or more dedicated hardware circuits. However, the use of software modules is preferred as it facilitates the update of UE3 and network devices to update their functions.

[0299] In the above aspects, 3GPP wireless communication (radio access) technology is used. However, any other wireless communication technology (such as WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed-line communication technologies (such as BBF access, cable access, optical access, etc.) may also be used according to the above aspects.

[0300] The items of the user device can include communication devices such as, for example, mobile phones, smartphones, user devices, personal digital assistants, laptop / tablet computers, web browsers, e - book readers, etc. Such mobile (or 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 should be understood that the described technology can be implemented on any communication device (mobile and / or generally fixed) that can be connected to a communication network to send and receive data, regardless of whether such a communication device is controlled by human input or software instructions stored in memory.

[0301] Various other modifications will be apparent to those skilled in the art and are not further elaborated here.

[0302] As will be understood by those skilled in the art, the present disclosure can be embodied as a method and a system. Accordingly, the present disclosure can take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0303] It will be appreciated that each block of the block diagrams can be implemented by computer program instructions. These computer program instructions are provided to the processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to manufacture a machine that creates means for causing instructions executed via the processor of the computer or other programmable data processing apparatus to perform the functions / operations specified in one or more blocks of the flowchart and / or block diagram. The general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a plurality of microprocessors, one or more microprocessors in combination with any other such arrangement.

[0304] 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 coupled 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.

[0305] The foregoing description of the disclosed examples is provided to enable a person skilled in the art to make or use the present disclosure. Various modifications to these 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 is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0306] Although the present disclosure has been particularly shown and described with reference to its exemplary embodiments, the present disclosure is not limited to these embodiments. Those skilled in the art will understand that various changes in form and details can be made therein without departing from the spirit and scope of the present disclosure as defined by the present specification. For example, the above embodiments are not limited to 5GS and are also applicable to communication systems other than 5GS (e.g., 6G systems, systems beyond 5G).

[0307] Appendix All or part of the exemplary embodiments disclosed above may be described as follows in the appendix, but are not limited thereto. (Appendix 1) A method of a first communication device, comprising: communicating with a second communication device; transmitting, to the second communication device, a single network slice selection assistance information (S-NSSAI) included in a pending network slice selection assistance information (NSSAI) related to reallocation of an access and mobility management function (AMF); and a method. (Appendix 2) The S-NSSAI is included in an Nnssf_NSSelection_Get message The method according to Appendix 1. (Appendix 3) Further including determining whether to include the S-NSSAI in the Nnssf_NSSelection_Get message The method according to Appendix 2. (Appendix 4) The S-NSSAI is included in the Requested NSSAI The method according to any one of Appendices 1 to 3. (Appendix 5) Determining a permitted NSSAI based on the S-NSSAI Transmitting the permitted NSSAI Further including The method according to any one of Appendices 1 to 4. (Appendix 6) Further including transmitting the first S-NSSAI of the first Pending NSSAI for one access and transmitting the second S-NSSAI of the second Pending NSSAI for another access The method according to any one of Appendices 1 to 5. (Appendix 7) The first communication device is an AMF device The method according to any one of Appendices 1 to 6. (Appendix 8) The second communication device is a Network Slice Selection Function (NSSF) device The method according to any one of Appendices 1 to 7. (Appendix 9) Receiving a single Network Slice Selection Assistance Information (S-NSSAI) of the Pending Network Slice Selection Assistance Information (NSSAI) Based on the S-NSSAI, determine an access and mobility management function (AMF) set or list of AMF addresses, and send the AMF set or list of AMF addresses, and including A method for a communication device. (Appendix 10) The S-NSSAI is included in the Nnssf_NSSelection_Get message, The method described in Appendix 9. (Appendix 11) The S-NSSAI is included in the Requested NSSAI, The method described in Appendix 9 or Appendix 10. (Appendix 12) Based on the S-NSSAI, determine the allowed NSSAI, and send the allowed NSSAI, and further including The method described in any of Appendix 9 to Appendix 11. (Appendix 13) Receive the first S-NSSAI of the first Pending NSSAI for one access and the second S-NSSAI of the second Pending NSSAI for another access, and Based on the first S-NSSAI and the second S-NSSAI, determine an AMF set or list of AMF addresses, and further including The method described in any of Appendix 9 to Appendix 12. (Appendix 14) The communication device is a network slice selection function (NSSF) device, The method described in any of Appendix 9 to Appendix 13. (Appendix 15) Communicate with a second communication device, and Transmit the single network slice selection assistance information (S-NSSAI) included in the Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device, and including The S-NSSAI is used in the procedure related to the reallocation of the Access and Mobility Management Function (AMF). Method of the first communication device. (Appendix 16) The S-NSSAI is included in the Requested NSSAI. The method described in Appendix 15. (Appendix 17) The S-NSSAI is included in the Radio Resource Control (RRC) setup complete message. The method described in Appendix 15 or 16. (Appendix 18) Further including determining whether to include the S-NSSAI in the RRC setup complete message. The method described in Appendix 17. (Appendix 19) The first communication device is in the CM-IDLE state. The method described in Appendix 17 or 18. (Appendix 20) The S-NSSAI is included in the UL information transfer message. The method described in Appendix 15 or 16. (Appendix 21) Further including determining whether to include the S-NSSAI in the UL information transfer message. The method described in Appendix 20. (Appendix 22) The first communication device is in the CM-CONNECTED state. The method described in Appendix 20 or 21. (Appendix 23) The first communication device is a user device, The method according to any one of Appendices 15 to 22. (Appendix 24) The second communication device is a Radio Access Network (RAN) node, The method according to any one of Appendices 15 to 23. (Appendix 25) Receiving a single network slice selection assistance information (S-NSSAI) of the pending network slice selection assistance information (NSSAI), Transmitting the S-NSSAI, including The S-NSSAI is used in the procedure regarding the reallocation of the Access and Mobility Management Function (AMF), Method of a communication device. (Appendix 26) The S-NSSAI is included in the radio resource control (RRC) setup complete message, The method according to Appendix 25. (Appendix 27) The S-NSSAI is included in the UL information transfer message, The method according to Appendix 25. (Appendix 28) The communication device is a Radio Access Network (RAN) node, The method according to any one of Appendices 25 to 27. (Appendix 29) Means for communicating with the second communication device, Means for transmitting single network slice selection assistance information (S-NSSAI) included in pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI) related to access and mobility management function (Access and Mobility Management Function: AMF) reallocation to a second communication device, including a first communication device. (Appendix 30) The S-NSSAI is included in the Nnssf_NSSelection_Get message, the first communication device described in Appendix 29. (Appendix 31) further including means for determining whether to include the S-NSSAI in the Nnssf_NSSelection_Get message, the first communication device described in Appendix 30. (Appendix 32) The S-NSSAI is included in the Requested NSSAI, the first communication device described in any one of Appendix 29 to Appendix 31. (Appendix 33) means for determining a permitted NSSAI based on the S-NSSAI, means for transmitting the permitted NSSAI, further including the first communication device described in any one of Appendix 29 to Appendix 32. (Appendix 34) further including means for transmitting the first S-NSSAI of the first Pending NSSAI for one access and transmitting the second S-NSSAI of the second Pending NSSAI for another access, the first communication device described in any one of Appendix 29 to Appendix 33. (Appendix 35) The first communication device is an AMF device, The first communication device described in any one of Appendices 29 to 34. (Appendix 36) The second communication device is a Network Slice Selection Function (NSSF) device. The first communication device described in any one of Appendices 29 to 35. (Appendix 37) Means for receiving a single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI). Means for determining an Access and Mobility Management Function (AMF) set or list of AMF addresses based on the S-NSSAI. Means for transmitting the AMF set or list of AMF addresses. Including A communication device. (Appendix 38) The S-NSSAI is included in the Nnssf_NSSelection_Get message. The communication device described in Appendix 37. (Appendix 39) The S-NSSAI is included in the Requested NSSAI. The communication device described in Appendix 37 or 38. (Appendix 40) Means for determining a permitted NSSAI based on the S-NSSAI. Means for transmitting the permitted NSSAI. Further including The communication device described in any one of Appendices 37 to 39. (Appendix 41) means for receiving a first S-NSSAI of a first Pending NSSAI for one access and a second S-NSSAI of a second Pending NSSAI for another access; means for determining a list of AMF sets or AMF addresses based on the first S-NSSAI and the second S-NSSAI; further comprising a communication device according to any one of Appendices 37 to 40. (Appendix 42) The communication device is a Network Slice Selection Function (NSSF) device. a communication device according to any one of Appendices 37 to 41. (Appendix 43) means for communicating with a second communication device; means for transmitting, to the second communication device, single network slice selection assistance information (S-NSSAI) included in Pending network slice selection assistance information (NSSAI); comprising The S-NSSAI is used in procedures related to reallocation of an Access and Mobility Management Function (AMF). a first communication device. (Appendix 44) The S-NSSAI is included in the Requested NSSAI. the first communication device according to Appendix 43. (Appendix 45) The S-NSSAI is included in a Radio Resource Control (RRC) setup complete message. the first communication device according to Appendix 43 or 44. (Appendix 46) Means for determining whether to include the S-NSSAI in the RRC setup completion message, further comprising The first communication device according to Appendix 45. (Appendix 47) The first communication device is in the CM-IDLE state. The first communication device according to Appendix 45 or 46. (Appendix 48) The S-NSSAI is included in the UL information transfer message. The first communication device according to Appendix 43 or 44. (Appendix 49) Means for determining whether to include the S-NSSAI in the UL information transfer message, further comprising The first communication device according to Appendix 48. (Appendix 50) The first communication device is in the CM-CONNECTED state. The first communication device according to Appendix 48 or 49. (Appendix 51) The first communication device is a user device. The first communication device according to any one of Appendices 43 to 50. (Appendix 52) The second communication device is a Radio Access Network (RAN) node. The first communication device according to any one of Appendices 43 to 51. (Appendix 53) Means for receiving a single Network Slice Selection Assistance Information (S-NSSAI) of the Pending Network Slice Selection Assistance Information (NSSAI), and Means for transmitting the S-NSSAI, and including The S-NSSAI is used in procedures related to the reallocation of the Access and Mobility Management Function (AMF). Communication device. (Appendix 54) The S-NSSAI is included in the Radio Resource Control (RRC) setup completion message. The communication device described in Appendix 53. (Appendix 55) The S-NSSAI is included in the UL information transfer message. The communication device described in Appendix 53. (Appendix 56) The communication device is a Radio Access Network (RAN) node. The communication device described in any of Appendix 53 to Appendix 55. (Appendix 57) Communicating with a second communication device. When the first communication device has Pending Network Slice Selection Assistance Information (NSSAI), sending the Requested NSSAI to the second communication device. Including The Requested NSSAI includes the Pending NSSAI. Method of the first communication device. (Appendix 58) The first communication device is the Access and Mobility Management Function (AMF). The method described in Appendix 57. (Appendix 59) The second communication device is the Network Slice Selection Function (NSSF). The method described in Appendix 57 or 58. (Appendix 60) The Requested NSSAI is the method described in any of Appendices 57 to 59, included in the Nnssf_NSSelection_Get message. (Appendix 57 to 59) (Appendix 61) The Requested NSSAI is the first Requested NSSAI, and further includes receiving a second Requested NSSAI from a User Equipment (UE). The first Requested NSSAI includes the second Requested NSSAI. The method described in any of Appendices 57 to 60. (Appendix 62) (Appendix 62) The Requested NSSAI is the first Requested NSSAI, and further includes receiving a second Requested NSSAI from a User Equipment (UE). The first Requested NSSAI includes the single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI. The method described in any of Appendices 57 to 60. (Appendix 63) (Appendix 63) The second Requested NSSAI is included in the registration request message. The method described in Appendix 61 or 62. (Appendix 64) Communicating with a second communication device. When the second communication device stores Pending Network Slice Selection Assistance Information (NSSAI), receiving the Requested NSSAI from the second communication device. The Requested NSSAI includes the Pending NSSAI. The method of the first communication device. (Appendix 65) The first communication device is a Network Slice Selection Function (NSSF). The method described in Appendix 64. (Appendix 66) The second communication device is an Access and Mobility Management Function (AMF). The method described in Appendix 64 or 65. (Appendix 67) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. The method described in any one of Appendices 64 to 66. (Appendix 68) The Requested NSSAI is the first Requested NSSAI, The first Requested NSSAI includes the second Requested NSSAI, The second Requested NSSAI is transmitted from a User Equipment (UE). The method described in any one of Appendices 64 to 67. (Appendix 69) The Requested NSSAI is the first Requested NSSAI, The first Requested NSSAI includes the single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI, The second Requested NSSAI is transmitted from a User Equipment (UE). The method described in any one of Appendices 64 to 67. (Appendix 70) The second Requested NSSAI is transmitted from the UE by a registration request message. The method according to Supplementary Note 68 or 69. (Supplementary Note 71) Based on the Requested NSSAI, determining a set of Access and Mobility Management Function (AMF) or a list of AMF addresses, Transmitting the set of AMF or the list of AMF addresses, further comprising The method according to any one of Supplementary Notes 64 to 70. (Supplementary Note 72) Means for communicating with a second communication device, When the first communication device has Pending Network Slice Selection Assistance Information (NSSAI), means for transmitting the Requested NSSAI to the second communication device, including The Requested NSSAI includes the Pending NSSAI, The first communication device. (Supplementary Note 73) The first communication device is an Access and Mobility Management Function (AMF), The first communication device according to Supplementary Note 72. (Supplementary Note 74) The second communication device is a Network Slice Selection Function (NSSF), The first communication device according to Supplementary Note 72 or 73. (Supplementary Note 75) The Requested NSSAI is included in the Nnssf_NSSelection_Get message, The first communication device according to any one of Supplementary Notes 72 to 74. (Supplementary Note 76) The Requested NSSAI is the first Requested NSSAI, It further includes means for receiving a second Requested NSSAI from a User Equipment (UE). The first Requested NSSAI includes the second Requested NSSAI. The first communication device described in any one of Appendices 72 to 75. (Appendix 77) The Requested NSSAI is the first Requested NSSAI and It further includes means for receiving a second Requested NSSAI from a User Equipment (UE). The first Requested NSSAI includes a single network slice selection assistance information (S-NSSAI) of the second Requested NSSAI. The first communication device described in any one of Appendices 72 to 75. (Appendix 78) The second Requested NSSAI is included in a registration request message. The first communication device described in Appendix 76 or 77. (Appendix 79) Means for communicating with a second communication device and When the second communication device stores pending network slice selection assistance information (NSSAI), means for receiving the Requested NSSAI from the second communication device. Including The Requested NSSAI includes the Pending NSSAI. The first communication device. (Appendix 80) The first communication device is a Network Slice Selection Function (NSSF). The first communication device described in Appendix 79. (Appendix 81) The second communication device is an Access and Mobility Management Function (AMF). The first communication device described in Appendix 79 or 80. (Appendix 82) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. The first communication device described in any one of Appendices 79 to 81. (Appendix 83) The Requested NSSAI is the first Requested NSSAI. The first Requested NSSAI includes the second Requested NSSAI. The second Requested NSSAI is transmitted from a User Equipment (UE). The first communication device described in any one of Appendices 79 to 82. (Appendix 84) The Requested NSSAI is the first Requested NSSAI. The first Requested NSSAI includes the single network slice selection assistance information (S-NSSAI) of the second Requested NSSAI. The second Requested NSSAI is transmitted from a User Equipment (UE). The first communication device described in any one of Appendices 79 to 82. (Appendix 85) The second Requested NSSAI is transmitted from the UE by a registration request message. The first communication device described in Appendix 83 or 84. (Appendix 86) Means for determining a set of Access and Mobility Management Function (AMF) or a list of AMF addresses based on the requested NSSAI, means for transmitting the set of AMF or the list of AMF addresses, further comprising, a first communication device according to any one of Appendices 79 to 85.

[0308] This application is based on Indian Patent Application No. 202211033471 filed on June 10, 2022, claims the benefit of its priority, and the disclosure thereof is incorporated herein by reference in its entirety.

Description of Signs

[0309] 3 User Equipment 20 Data Network 201 AF 31 Transceiver Circuit 32 Antenna 33 Control Unit 34 User Interface 35 USIM 36 Memory 361 Operating System 362 Communication Control Module 3621 Transceiver Control Module 5 (R)AN Node 51 Transceiver Circuit 52 Antenna 53 Network Interface 54 Control Unit 55 Memory 551 Operating System 552 Communication Control Module 5521 Transceiver Control Module 60 RU 601 Transceiver Circuit 602 Antenna 603 Network Interface 604 Control Unit 605 Memory 6051 Operating System 6052 Communication Control Module 60521 Transceiver Control Module 61 DU 611 Transceiver Circuit 612 Network Interface 613 Control Unit 614 Memory 6141 Operating System 6142 Communication Control Module 61421 Transceiver Control Module 62 CU 621 Transceiver Circuit 622 Network Interface 623 Control Unit 624 Memory 6241 Operating System 6242 Communication Control Module 62421 Transceiver Control Module 7 Core Network 70 AMF 701 Transceiver Circuit 702 Network Interface 703 Control Unit 704 Memory 7041 Operating System 7042 Communication Control Module 70421 Transceiver Control Module 71 SMF 72 UPF 73 PCF 731 Transceiver Circuit 732 Network Interface 733 Control Unit 734 Memory 7341 Operating System 7342 Communication Control Module 73421 Transceiver Control Module 74 AUSF 741 Transceiver Circuit 742 Network Interface 743 Control Unit 744 Memory 7441 Operating System 7442 Communication Control Module 74421 Transceiver Control Module 75 UDM 751 Transceiver Circuit 752 Network Interface 753 Control Unit 754 Memory 7541 Operating System 7542 Communication Control Module 75421 Transceiver Control Module 76 NSSF 761 Transceiver Circuit 762 Network Interface 763 Control Unit 764 Memory 7641 Operating System 7642 Communication Control Module 76421 Transceiver Control Module

Claims

1. A method for a first communication device, comprising: communicating with a second communication device; when the first communication device holds Pending Network Slice Selection Assistance Information (NSSAI), sending Requested NSSAI to the second communication device; wherein the Requested NSSAI includes the Pending NSSAI; the method.

2. The method according to claim 1, wherein the first communication device is an Access and Mobility Management Function (AMF). The method according to claim 1.

3. The method according to claim 1 or 2, wherein the second communication device is a Network Slice Selection Function (NSSF). The method according to claim 1 or 2.

4. The method according to any one of claims 1 to 3, wherein the Requested NSSAI is included in an Nnssf_NSSelection_Get message. The method according to any one of claims 1 to 3.

5. The Requested NSSAI is a first Requested NSSAI, further comprising receiving a second Requested NSSAI from a User Equipment (UE), wherein the first Requested NSSAI includes the second Requested NSSAI. The method according to any one of claims 1 to 4.

6. The Requested NSSAI is a first Requested NSSAI, further comprising receiving a second Requested NSSAI from a User Equipment (UE), wherein the first Requested NSSAI includes a Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI. The method according to any one of claims 1 to 4.

7. The method according to claim 5 or 6, wherein the second Requested NSSAI is included in a registration request message. The method according to claim 5 or 6.

8. A method for a first communication device, comprising: communicating with a second communication device; When Pending Network Slice Selection Assistance Information (NSSAI) is held in the second communication device, receiving a Requested NSSAI from the second communication device, including the Requested NSSAI includes the Pending NSSAI, Method.

9. The first communication device is a Network Slice Selection Function (NSSF). The method according to claim 8.

10. The second communication device is an Access and Mobility Management Function (AMF). The method according to claim 8 or 9.

11. The Requested NSSAI is included in an Nnssf_NSSelection_Get message. The method according to any one of claims 8 to 10.

12. The Requested NSSAI is a first Requested NSSAI, the first Requested NSSAI includes a second Requested NSSAI, the second Requested NSSAI is transmitted from a User Equipment (UE). The method according to any one of claims 8 to 11.

13. The Requested NSSAI is a first Requested NSSAI, the first Requested NSSAI includes a single Network Slice Selection Assistance Information (S-NSSAI) of a second Requested NSSAI, the second Requested NSSAI is transmitted from a User Equipment (UE). The method according to any one of claims 8 to 11.

14. The second Requested NSSAI is transmitted from the UE by a registration request message. The method according to claim 12 or 13.

15. Based on the Requested NSSAI, determining a set of Access and Mobility Management Function (AMF) or a list of AMF addresses, transmitting the set of AMF or the list of AMF addresses, further comprising, The method according to any one of claims 8 to 14.

16. A method of a first communication device, communicating with a second communication device, transmitting single network slice selection assistance information (S-NSSAI) included in Pending network slice selection assistance information (NSSAI) to the second communication device, comprising, The S-NSSAI is used in procedures related to the reallocation of the Access and Mobility Management Function (AMF). Method.

17. The S-NSSAI is included in the Requested NSSAI, The method according to claim 16.

18. The S-NSSAI is included in a Radio Resource Control (RRC) setup complete message, The method according to claim 16 or 17.

19. further comprising determining whether to include the S-NSSAI in the RRC setup complete message, The method according to claim 18.

20. The first communication device is in the CM-IDLE state, The method according to claim 18 or 19.

21. The S-NSSAI is included in a UL information transfer message, The method according to claim 16 or 17.

22. further comprising determining whether to include the S-NSSAI in the UL information transfer message, The method according to claim 21.

23. The first communication device is in the CM-CONNECTED state, The method according to claim 21 or 22.

24. The first communication device is a user equipment, The method according to any one of claims 16 to 23.

25. The second communication device is a Radio Access Network (RAN) node. The method according to any one of claims 16 to 24. **Claim 26** A method of a communication device, comprising: receiving a single network slice selection assistance information (S-NSSAI) of Pending network slice selection assistance information (NSSAI); transmitting the S-NSSAI; wherein the S-NSSAI is used in a procedure related to reallocation of an Access and Mobility Management Function (AMF). Method. **Claim 27** The S-NSSAI is included in a radio resource control (RRC) setup completion message. The method according to claim 26. **Claim 28** The S-NSSAI is included in a UL information transfer message. The method according to claim 26. **Claim 29** The communication device is a Radio Access Network (RAN) node. The method according to any one of claims 26 to 28. **Claim 30** A first communication device, comprising: means for communicating with a second communication device; means for transmitting a Requested NSSAI to the second communication device when the first communication device holds Pending network slice selection assistance information (NSSAI), wherein the Requested NSSAI includes the Pending NSSAI. First communication device. **Claim 31** The first communication device is an Access and Mobility Management Function (AMF). The first communication device according to claim 30. **Claim 32** The second communication device is a Network Slice Selection Function (NSSF). The first communication device according to claim 30 or 31.

33. The Requested NSSAI is included in the Nnssf_NSSelection_Get message, The first communication device according to any one of claims 30 to 32.

34. The Requested NSSAI is a first Requested NSSAI, The means for receiving a second Requested NSSAI from a user equipment (UE) is further included, The first Requested NSSAI includes the second Requested NSSAI, The first communication device according to any one of claims 30 to 33.

35. The Requested NSSAI is a first Requested NSSAI, The means for receiving a second Requested NSSAI from a user equipment (UE) is further included, The first Requested NSSAI includes a single network slice selection assistance information (S-NSSAI) of the second Requested NSSAI, The first communication device according to any one of claims 30 to 33.

36. The second Requested NSSAI is included in a registration request message, The first communication device according to claim 34 or 35.

37. A first communication device, Means for communicating with a second communication device, When Pending network slice selection assistance information (NSSAI) is held in the second communication device, means for receiving a Requested NSSAI from the second communication device, Including, The Requested NSSAI includes the Pending NSSAI, The first communication device.

38. The first communication device is a network slice selection function (NSSF), The first communication device according to claim 37.

39. The second communication device is an Access and Mobility Management Function (AMF). The first communication device according to claim 37 or 38.

40. The Requested NSSAI is included in the Nnssf_NSSelection_Get message. The first communication device according to any one of claims 37 to 39.

41. The Requested NSSAI is a first Requested NSSAI. The first Requested NSSAI includes a second Requested NSSAI. The second Requested NSSAI is transmitted from a User Equipment (UE). The first communication device according to any one of claims 37 to 40.

42. The Requested NSSAI is a first Requested NSSAI. The first Requested NSSAI includes a single network slice selection assistance information (S-NSSAI) of a second Requested NSSAI. The second Requested NSSAI is transmitted from a User Equipment (UE). The first communication device according to any one of claims 37 to 40.

43. The second Requested NSSAI is transmitted from the UE by a registration request message. The first communication device according to claim 41 or 42.

44. Means for determining a set of Access and Mobility Management Function (AMF) or a list of AMF addresses based on the Requested NSSAI; Means for transmitting the set of AMF or the list of the AMF addresses; Further comprising: The first communication device according to any one of claims 37 to 43.

45. A first communication device, Means for communicating with a second communication device; Means for transmitting single network slice selection assistance information (S-NSSAI) included in pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI) to the second communication device, comprising, wherein the S-NSSAI is used in procedures related to reallocation of an access and mobility management function (Access and Mobility Management Function: AMF), a first communication device.

46. The S-NSSAI is included in the Requested NSSAI, The first communication device according to claim 45.

47. The S-NSSAI is included in a radio resource control (Radio Resource Control: RRC) setup completion message, The first communication device according to claim 45 or 46.

48. Further comprising means for determining whether to include the S-NSSAI in the RRC setup completion message, The first communication device according to claim 47.

49. The first communication device is in the CM-IDLE state, The first communication device according to claim 47 or 48.

50. The S-NSSAI is included in a UL information transfer message, The first communication device according to claim 45 or 46.

51. Further comprising means for determining whether to include the S-NSSAI in the UL information transfer message, The first communication device according to claim 50.

52. The first communication device is in the CM-CONNECTED state, The first communication device according to claim 50 or 51.

53. The first communication device is a user device, The first communication device according to any one of claims 45 to 52.

54. The second communication device is a radio access network (Radio Access Network: RAN) node, The first communication device according to any one of claims 45 to 53.

55. A communication device, Means for receiving a single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (Network Slice Selection Assistance Information: NSSAI); Means for transmitting the S-NSSAI; comprising; the S-NSSAI is used in procedures related to the reallocation of an access and mobility management function (AMF); A communication device. **Claim 56** The S-NSSAI is included in a radio resource control (RRC) setup completion message; The communication device according to claim 55. **Claim 57** The S-NSSAI is included in a UL information transfer message; The communication device according to claim 55. **Claim 58** The communication device is a radio access network (RAN) node; The communication device according to any one of claims 55 to 57.

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