First communication device method and 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 first communication device method, a communication device method, a first communication device, and a communication device. [Background technology]

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

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

[0004] According to 3GPP TS 24.501 [5], the 3GPP specifications further define a mechanism whereby a registration procedure is initiated by the User Equipment (UE) while an NSSAA procedure is ongoing. In this case, the UE does not include in the Requested NSSAI the S-NSSAI(s) that are managed as Pending NSSAIs in the UE according to 3GPP TS 24.501 [5]. Summary of the Invention [Problem to be solved by the invention]

[0005] The current 3GPP specifications leave some unclear situations regarding NSSAA procedures.

[0006] For example, according to 3GPP TS 23.502 [3], when an Access and Mobility Management Function (AMF) receives a Registration Request message from a UE including a Requested NSSAI, the AMF may send an Nnssf_NSSelection_Get message including the received Requested NSSAI to a Network Slice Selection Function (NSSF). Upon receiving the Nnssf_NSSelection_Get message from the AMF, the NSSF provides an AMF set or a list of candidate AMF(s) along with the Allowed NSSAI. The AMF set or list of candidate AMF(s) and the Allowed NSSAI are selected by the NSSF based on the Requested NSSAI received from the AMF as input information. The AMF can then perform a Registration with AMF Reallocation procedure to change the AMF according to section 4.2.2.2.3 of 3GPP TS 23.502 [3].

[0007] Also, for example, as mentioned above, the 3GPP specifications define a mechanism whereby a registration procedure is initiated by the UE while an NSSAA procedure is ongoing, in which case the UE does not include in the Requested NSSAI any S-NSSAI(s) that are considered as Pending NSSAIs at the UE according to 3GPP TS 24.501 [5].

[0008] For example, while an NSSAA procedure is in progress, when an AMF queries the NSSF to discover or select an AMF set or a list of candidate AMF(s) during the registration procedure, 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) in the Pending NSSAI may become part of the Authorized NSSAI upon successful completion of the NSSAA procedure.

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

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

[0012] This could result in significant service degradation for all services that use network slices in the 5G System (5GS). [Means for solving the problem]

[0013] Aspects of the present disclosure include a method in a first communications device, the method including communicating with a second communications device, the method including, if the first communications device has a Pending Network Slice Selection Assistance Information (NSSAI), sending a Requested NSSAI to the second communications device, the Requested NSSAI including the Pending NSSAI. Aspects of the present disclosure include a method in a first communications device, the method including communicating with a second communications device, the method including receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communications device if a Pending NSSAI is stored in the second communications device, the Requested NSSAI including the Pending NSSAI. An aspect of the present disclosure includes a method in a first communication device, the method including communicating with a second communication device, the method including transmitting Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device, the S-NSSAI being used for a procedure related to Access and Mobility Management Function (AMF) reallocation. Aspects of the present disclosure include a method of a communications apparatus, the method including receiving Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI), the method including transmitting the S-NSSAI, the S-NSSAI being used for a procedure related to Access and Mobility Management Function (AMF) reassignment. One aspect of the present disclosure includes a first communications device. The first communications device includes means for communicating with a second communications device. The first communications device includes means for, if the first communications device has a Pending Network Slice Selection Assistance Information (NSSAI), transmitting a Requested NSSAI to the second communications device. The Requested NSSAI includes the Pending NSSAI. One aspect of the present disclosure includes a first communications device, the first communications device including means for communicating with a second communications device, the first communications device including means for receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communications device, where a Pending NSSAI is stored in the second communications device, the Requested NSSAI including 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 Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device. The S-NSSAI is used for a procedure related to reassignment of an Access and Mobility Management Function (AMF). One aspect of the present disclosure includes a communications apparatus, the communications apparatus including means for receiving Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI), the communications apparatus including means for transmitting the S-NSSAI, the S-NSSAI being used for a procedure related to Access and Mobility Management Function (AMF) reassignment. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a signaling diagram of a first example of the first embodiment. [Figure 2] FIG. 2 is a signaling diagram of a second example of the first embodiment. [Figure 3] FIG. 3 is a diagram showing an outline of the system. [Figure 4] FIG. 4 is a block diagram illustrating a UE. [Figure 5] FIG. 5 is a block diagram illustrating an (R)AN node. [Figure 6] FIG. 6 is a diagram illustrating a system overview of an (R)AN node based on the O-RAN architecture. [Figure 7] FIG. 7 is a block diagram illustrating an RU. [Figure 8] FIG. 8 is a block diagram showing a DU. [Figure 9] FIG. 9 is a block diagram showing a CU. [Figure 10] FIG. 10 is a block diagram illustrating the AMF. [Figure 11] FIG. 11 is a block diagram illustrating a PCF. [Figure 12] FIG. 12 is a block diagram showing the AUSF. [Figure 13] FIG. 13 is a block diagram illustrating the UDM. [Figure 14] FIG. 14 is a block diagram illustrating the NSSF. [Figure 15] Figure 15 is a diagram illustrating registration using the AMF reassignment procedure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Abbreviation For the purposes of this document, 3GPP TR 21.905 [1] and the following abbreviations apply. Abbreviations defined in this document take precedence over definitions of the same abbreviations in 3GPP TR 21.905 [1], if any. 4G-GUTI 4G Globally Unique Temporary UE Identity 5GC 5G Core Network 5GLAN 5G Local Area Network 5GS 5G System 5G-AN 5G Access Network 5G-AN PDB 5G Access Network Packet Delay Budget 5G-EIR 5G-Equipment Identity Register 5G-GUTI 5G Globally Unique Temporary Identifier 5G-BRG 5G Broadband Residential Gateway 5G-CRG 5G Cable Residential Gateway 5G GM 5G Grand Master 5G-RG 5G Residential Gateway 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier 5G VN 5G Virtual Network 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AMF-G Geographically selected Access and Mobility Management Function AMF-NG Non-Geographically selected Access and Mobility Management Function ANDSF Access Network Discovery and Selection Function AS Access Stratum ATSSS Access Traffic Steering, Switching, Splitting ATSSS-LL ATSSS Low-Layer AUSF Authentication Server Function AUTN Authentication token BCCH Broadcast Control Channel BMCA Best Master Clock Algorithm BSF Binding Support Function CAG Closed Access Group CAPIF Common API Framework for 3GPP northbound APIs CHF Charging Function CN PDB Core Network Packet Delay Budget CP Control Plane DAPS Dual Active Protocol Stacks DL Downlink DN Data Network DNAI DN Access Identifier DNN Data Network Name DRX Discontinuous Reception DS-TT Device-side TSN translator ePDG evolved Packet Data Gateway EBI EPS Bearer Identity EPS Evolved Packet System EUI Extended Unique Identifier FAR Forwarding Action Rule FN-BRG Fixed Network Broadband RG FN-CRG Fixed Network Cable RG FN-RG Fixed Network RG FQDN Fully Qualified Domain Name GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier GUTI Globally Unique Temporary UE Identity HPLMN Home Public Land Mobile Network HR Home Routed (roaming) IAB Integrated access and backhaul IMEI / TAC IMEI Type Allocation Code IPUPS Inter PLMN UP Security I-SMF Intermediate SMF I-UPF Intermediate UPF LADN Local Area Data Network LBO Local Break Out (roaming) LMF Location Management Function LoA Level of Automation LPP LTE Positioning Protocol LRF Location Retrieval Function MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MITM Man in the Middle MNC Mobile Network Code MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol N3IWF Non-3GPP InterWorking Function N3GPP Non-3GPP access N5CW Non-5G-Capable over WLAN NAI Network Access Identifier NAS Non-Access-Stratum NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NID Network identifier NPN Non-Public Network NR New Radio NRF Network Repository Function NSI ID Network Slice Instance Identifier NSSAA Network Slice-Specific Authentication and Authorization NSSAAF Network Slice-Specific Authentication and Authorization Function NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy NSSRG Network Slice Simultaneous Registration Group NW-TT Network-side TSN translator NWDAF Network Data Analytics Function PCF Policy Control Function PCO Protocol Configuration Options PDB Packet Delay Budget PDR Packet Detection Rule PDU Protocol Data Unit PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public Land Mobile Network PNI-NPN Public Network Integrated Non-Public Network PPD Paging Policy Differentiation PPF Paging Proceed Flag PPI Paging Policy Indicator PSA PDU Session Anchor PTP Precision Time Protocol QFI QoS Flow Identifier QoE Quality of Experience RACS Radio Capabilities Signalling optimisation (R)AN (Radio) Access Network RAT Radio Access Technology RG Residential Gateway RIM Remote Interference Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RSN Redundancy Sequence Number SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SMF Session Management Function SMSF Short Message Service Function SN Sequence Number SN Name Serving Network Name SNPN Stand-alone Non-Public Network S-NSSAI Single Network Slice Selection Assistance Information SSC Session and Service Continuity SSCMSP Session and Service Continuity Mode Selection Policy SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier SV Software Version TMSI Temporary Mobile Subscriber Identity TNAN Trusted Non-3GPP Access Network TNAP Trusted Non-3GPP Access Point TNGF Trusted Non-3GPP Gateway Function TNL Transport Network Layer TNLA Transport Network Layer Association TSC Time Sensitive Communication TSCAI TSC Assistance Information TSN Time Sensitive Networking TSN GM TSN Grand Master TSP Traffic Steering Policy TT TSN Translator TWIF Trusted WLAN Interworking Function UCMF UE radio Capability Management Function UDM Unified Data Management UDR Unified Data Repository UDSF Unstructured Data Storage Function UE User Equipment UL Uplink UL CL Uplink Classifier UPF User Plane Function UPSI UE Policy Section Identifier URLLC: Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy VID VLAN Identifier VLAN Virtual Local Area Network VPLMN Visited Public Land Mobile Network W-5GAN Wireline 5G Access Network W-5GBAN Wireline BBF Access Network W-5GCAN Wireline 5G Cable Access Network W-AGF Wireline Access Gateway Function

[0016] definition For the purposes of this document, the terms and definitions in 3GPP TR 21.905 [1] and below apply. Terms defined in this document take precedence over any definition of the same term in 3GPP TR 21.905 [1]. [Prior art documents] [Non-patent literature]

[0017] [Non-Patent Document 1] [1] 3GPP TR 21.905: “Vocabulary for 3GPP Specifications”.V17.1.0(2021-12) [Non-patent document 2] [2] 3GPP TS 23.501: “System architecture for the 5G System (5GS)”.V17.4.0(2022-03) [Non-patent document 3] [3] 3GPP TS 23.502: “Procedures for the 5G System (5GS)”.V17.4.0(2022-03) [Non-patent document 4] [4] 3GPP TS 23.503: “Policy and charging control framework for the 5G System(5GS)Stage 2” V17.4.0(2022-03) [Non-Patent Document 5] [5] 3GPP TS 24.501: “Non-Access-Stratum (NAS) protocol for 5G System (5GS) Stage 3”.V17.6.1 (2022-03)

[0018] General Those skilled in the art will understand that elements in the figures are illustrated for simplicity and may not necessarily be drawn to scale. Further, with respect to configurations of devices, one or more components of the device may be represented in the figures by conventional symbols, and the figures may show only certain details relevant to an understanding of aspects of the present disclosure so as not to obscure the figures with details that will be readily apparent to one of ordinary skill in the art having the benefit of the description herein.

[0019] For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made to the embodiments illustrated in the drawings and specific language will be used to describe them. It will nevertheless 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 skilled in the art, are to be construed as being within the scope of the present disclosure.

[0020] The terms "comprises," "including," or any other variations thereof, are intended to cover non-exclusive inclusions, such that a process or method that includes a list of steps does not include only those steps, but may include other steps that are not expressly listed or that are inherent in such process or method. Similarly, one or more devices or entities or subsystems or elements or structures or components preceded by "comprising..." does not, without further constraints, exclude the presence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures, or additional components. Throughout this specification, appearances of the phrases "in an embodiment," "in another embodiment," and similar language may, but need not, all refer to the same embodiment.

[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 are not intended to be limiting.

[0022] In the following specification and claims, reference will be made to a number of terms that may be defined to have the following meanings: The singular forms "a," "an," and "said" include plural references unless the context clearly dictates otherwise.

[0023] As used herein, information is associated with data and knowledge, as data is meaningful information and represents values ​​attributed to parameters. Further knowledge refers to an understanding of abstract or concrete concepts. Note that this exemplary system is simplified to facilitate explanation of the disclosed subject matter and is not intended to limit the scope of the present disclosure. Other devices, systems, and settings can be used in addition to or instead of the system to practice aspects disclosed herein, and all such aspects are considered to be within the scope of the present disclosure.

[0024] Furthermore, each aspect or element included in each of the following aspects may be implemented independently or in any combination. These aspects include novel features that are different from one another. Therefore, these aspects contribute to achieving different objectives or solving different problems, and to obtaining different advantages.

[0025] An exemplary object of the present disclosure is to provide a method and apparatus that can solve the above problems.

[0026] The following list describes the intended interpretation of terms used in this disclosure: -Subscribed S-NSSAI, Subscribed S-NSSAIs, or Subscribed S-NSSAI(s): This can be equal to the list of S-NSSAI(s) in the Subscribed NSSAI, or the S-NSSAI(s) in the Subscribed NSSAI. -Allowed S-NSSAI, Allowed S-NSSAIs, or Allowed S-NSSAI(s): This can be equal to the list of S-NSSAI(s) in Allowed NSSAI, or the S-NSSAI(s) in Allowed NSSAI. Configured S-NSSAI, Configured S-NSSAIs, or Configured S-NSSAI(s): This can be equal to the list of S-NSSAI(s) in the Configured NSSAI, or the S-NSSAI(s) in the Configured NSSAI. -Rejected S-NSSAI, Rejected S-NSSAIs or Rejected S-NSSAI(s): This can be equal to the list of S-NSSAI(s) in the Rejected NSSAI or the S-NSSAI(s) in the Rejected NSSAI. -Pending S-NSSAI, Pending S-NSSAI(s), or Pending S-NSSAI(s): Can be equal to the list of S-NSSAI(s) in the Pending NSSAI, or the S-NSSAI(s) in the Pending NSSAI.

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

[0028] A method for a first communication device according to an example aspect of the present disclosure includes communicating with a second communication device, the method including transmitting, to the second communication device, Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) for a procedure related to Access and Mobility Management Function (AMF) reallocation.

[0029] A method of a communications device according to an example aspect of the present disclosure includes receiving Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI). The method includes determining, based on the S-NSSAI, an Access and Mobility Management Function (AMF) set or a list of AMF addresses. The method includes transmitting the AMF set or the list of AMF addresses.

[0030] A method for a first communication device according to an example aspect of the present disclosure includes communicating with a second communication device, the method including transmitting Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device.

[0031] A method for a communications device according to an example aspect of the present disclosure includes receiving Single Network Slice Selection Assistance Information (S-NSSAI) from Pending Network Slice Selection Assistance Information (NSSAI). The method includes transmitting the S-NSSAI. The S-NSSAI is used for a procedure related to Access and Mobility Management Function (AMF) reassignment.

[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 configured to communicate with a second communication device, and the at least one hardware processor configured to transmit, to the second communication device, Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) for a procedure related to Access and Mobility Management Function (AMF) reallocation.

[0033] A communications apparatus 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 Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI). The at least one hardware processor is configured to determine, based on the S-NSSAI, an Access and Mobility Management Function (AMF) set or a list of AMF addresses. The at least one hardware processor is configured to transmit the AMF set 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 Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) to the second communication device. The S-NSSAI is used for a procedure related to Access and Mobility Management Function (AMF) reallocation.

[0035] A communications apparatus 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 Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI). The at least one hardware processor is configured to transmit the S-NSSAI. The S-NSSAI is used for a procedure related to Access and Mobility Management Function (AMF) reallocation.

[0036] First aspect When a UE requests access to S-NSSAI(s) (e.g., when the UE sends a Registration Request message including a Requested NSSAI that includes S-NSSAI(s)), the serving PLMN performs NSSAA for the S-NSSAI(s) of the HPLMN that are the subject of the NSSAA based on the subscription information. When the UE sends a Registration Request message including S-NSSAI(s) in the Requested NSSAI that are the subject of the NSSAA, the AMF sends a Registration Accept message that includes the S-NSSAI(s) in the list of Pending NSSAIs (e.g., the AMF sends a Registration Accept message including a Pending NSSAI that includes S-NSSAI(s)). After completing the registration procedure (e.g., after sending the Registration Accept message), the AMF initiates the NSSAA procedure for the S-NSSAI(s) in the Pending NSSAI. If the NSSAA procedure is successful, the AMF informs the UE that the S-NSSAI in the Pending NSSAI is now available and causes the UE to remove the S-NSSAI(s) from the storage of Pending NSSAI in the UE and place them in the storage of Allowed NSSAI in the UE.

[0037] The NSSAA procedure makes it possible to perform authentication and authorization specific to the use of network slices using an AAA server located in an external network.

[0038] According to 3GPP TS 23.502 [3], when an AMF receives a registration request message including a Requested NSSAI from a UE, the AMF sends an Nnssf_NSSelection_Get message including the received Requested NSSAI to the NSSF to discover appropriate AMF(s) that can support the network slice in the Requested NSSAI as much as possible. When the NSSF receives the Nnssf_NSSelection_Get message from the AMF, it provides an AMF set or a list of candidate AMF(s) to be used to serve the UE along with the allowed NSSAI. The AMF set or list of candidate AMF(s) and the allowed NSSAI are selected by the NSSF based on the Requested NSSAI received from the AMF as input information. The AMF can then perform a registration via AMF reallocation procedure to change the AMF according to section 4.2.2.2.3 of 3GPP TS 23.502 [3].

[0039] While the NSSAA procedure is in progress, if the AMF 70 queries the NSSF 76 during the registration procedure to discover a suitable AMF (e.g., to select or determine an AMF set or a list of candidate AMF(s)), the Requested NSSAI as input information to the NSSF does not include the S-NSSAI(s) that are within the Pending NSSAI.

[0040] However, if the NSSAA procedure is completed successfully, the S-NSSAI(s) in the Pending NSSAI may be added to the Authorized NSSAI.

[0041] In this case, once the NSSAA procedure is successfully completed, the S-NSSAI(s) in the Pending NSSAI may be added to the Authorized NSSAI, and therefore the S-NSSAI(s) in the Pending NSSAI need to be considered by the NSSF76 to discover the appropriate AMF. The first aspect is intended to solve the above problem.

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

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

[0044] Step 0. The Network Slice-Specific Authentication and Authorization (NSSAA) procedure is underway by the UE 3, as defined in section 4.2.9.2 of 3GPP TS 23.502 [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, UE 3 may perform 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 an NSSAA procedure, the first NSSAA procedure for S-NSSAI 1 was performed in step 0 and may be in progress.

[0048] If the first NSSAA procedure for S-NSSAI1 is in progress, UE3 and AMF70 may have a Pending NSSAI that includes S-NSSAI1.

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

[0050] Step 1. While the NSSAA procedure is in progress, the UE 3 sends a registration request message to the AMF 70, and steps 1 to 3c are performed as described in the registration procedure with 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 for S-NSSAI1 described above is in progress, UE3 may perform 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 determines that the second registration request message needs to be rerouted to another AMF (e.g., if AMF70 is not an appropriate AMF to serve UE3), AMF70 may perform the registration procedure by AMF reallocation in step 1 (i.e., steps 1 to 3c may be performed as described in the registration procedure by AMF reallocation).

[0053] The registration procedure due to AMF re-allocation may also be expressed as a procedure related to AMF re-allocation.

[0054] Step 2. The AMF 70 sends an Nnssf_NSSelection_Get message containing the Requested NSSAI and the Pending NSSAI to the NSSF 76. The Requested NSSAI is captured by the AMF 70 by copying it from the Registration Request message received from the UE 3 in step 1. If an NSSAI procedure is ongoing for an S-NSSAI, i.e., if the AMF 70 manages such S-NSSAI(s) as Pending NSSAI, the Pending NSSAI is captured by the AMF 70.

[0055] For example, if UE3 sends a second registration request message including a second Requested NSSAI including S-NSSAI2 in step 1, AMF70 may include the second Requested NSSAI including 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 ongoing in step 0, and AMF70 may manage (or have) a Pending NSSAI that includes S-NSSAI1. In this case, AMF70 may include a Pending NSSAI that includes S-NSSAI1 of step 2 in the Nnssf_NSSelection_Get message.

[0057] For example, AMF70 may 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] The AMF 70 may send an Nnssf_NSSelection_Get message for the registration procedure with AMF reassignment.

[0060] For example, the Nnssf_NSSelection_Get message may include a Pending NSSAI that includes any Pending S-NSSAI(s) stored in the AMF 70 (e.g., S-NSSAI(s) included in the Pending NSSAI).

[0061] For example, the Nnssf_NSSelection_Get message may include a Pending NSSAI that includes the S-NSSAI included in the Requested NSSAI(s) of the Registration Request message received from the UE 3.

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

[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 NSSF 76 sends an Nnssf_NSSelection_Get Response message to the AMF 70, including at least one of an AMF set, a list of AMF addresses, and a list of candidate AMF(s). The Nnssf_NSSelection_Get Response message may include an Allowed NSSAI. The NSSF 76 considers the received Requested NSSAI and the received Pending NSSAI to discover or determine the AMF set or list of AMF addresses or list of candidate AMF(s).

[0065] For example, the NSSF 76 may discover or determine the AMF(s) that can process the S-NSSAI(s) in the Requested NSSAI and Pending NSSAI.

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

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

[0068] For example, if the Nnssf_NSSelection_Get message includes a Requested NSSAI that includes S-NSSAI2 and a Pending NSSAI that includes S-NSSAI1, NSSF76 can discover AMF(s) that can process S-NSSAI1 and S-NSSAI2, discover (or determine) the addresses of the AMF(s), and include the addresses in the 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 Section 4.2.2.2.3 of 3GPP TS 23.502 [3] for Registration by AMF Re-allocation. For example, some of steps 5 to 8 may be performed.

[0071] For example, if a Pending NSSAI is not provided or if the Pending NSSAI includes S-NSSAI(s) that are not valid in the serving PLMN, then based on the subscribed S-NSSAI(s) and operator configuration, the NSSF76 may also determine the configured NSSAI(s) for the serving PLMN and, if applicable, the associated mapping of the configured NSSAI(s) to the HPLMN S-NSSAI(s), so that these may be configured in the UE3.

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

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

[0074] For example, if the first NSSAA procedure for S-NSSAI1 as described above is in progress in step 0, and AMF70 includes a Pending NSSAI including S-NSSAI1 in the Nnssf_NSSelection_Get message in step 2, and AMF70 receives a Rejected NSSAI including S-NSSAI1 from NSSF76, AMF70 may abort the first NSSAA procedure.

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

[0076] According to a first example of the first aspect, it is possible to solve the above-mentioned problem. For example, the first example of the first aspect can solve a problem that after an NSSAA procedure, all service(s) using S-NSSAI(s) newly added to the authorized 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 a problem such as significant service degradation of all service(s) using network slicing in 5GS.

[0077] Modification 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 may add the S-NSSAI(s) in the Pending NSSAI to the Requested NSSAI. As a result, the Requested NSSAI in the Nnssf_NSSelection_Get message may include the S-NSSAI(s) received from the UE 3 in 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, if the AMF 70 has a Pending NSSAI that includes S-NSSAI1, the AMF 70 can include S-NSSAI1 in the Requested NSSAI in the Nnssf_NSSelection_Get message. In this case, the AMF 70 does not need to include the Pending NSSAI in the Nnssf_NSSelection_Get message.

[0079] When the NSSF 76 receives the Nnssf_NSSelection_Get message, the NSSF 76 can find the AMF set or list of AMF addresses based on the received Requested NSSAI.

[0080] Modification 2 of the first example of the first aspect: In step 3, the NSSF 76 may construct an Authorized NSSAI taking into account the received Pending NSSAI and the received Requested NSSAI. Since the S-NSSAI(s) in the Pending NSSAI cannot be part of the Authorized NSSAI, if the S-NSSAI(s) are received as Pending NSSAIs from the AMF 70, the NSSF 76 may extract the S-NSSAI(s) from the Authorized NSSAI.

[0081] For example, the NSSF76 may not include the S-NSSAI(s) included in the Pending NSSAI in the Authorized NSSAI.

[0082] For example, the NSSF76 may determine an authorized NSSAI (e.g., the contents of the authorized NSSAI) based on at least one of a Pending NSSAI (e.g., S-NSSAI(s) in the Pending NSSAI) and a Requested NSSAI (e.g., S-NSSAI(s) in the Requested NSSAI).

[0083] For example, if the Pending NSSAI includes S-NSSAI A and the Requested NSSAI includes S-NSSAI A and S-NSSAI B, the NSSF 76 may construct an Authorized NSSAI that includes S-NSSAI B.

[0084] The second example of the first aspect can be modified as described in the second variation of the first example of the first aspect.

[0085] Modification 3 of the first example of aspect 1: Upon receiving the Nnssf_NSSelection_Get response message in step 3, in step 4, when the AMF 70 notifies the UE 3 of the authorized NSSAI by setting the authorized NSSAI in the registration accept message, the AMF 70 can construct the authorized NSSAI taking into account the Pending NSSAI in the AMF 70 and the authorized NSSAI received from the NSSF 76. Since the S-NSSAI(s) in the Pending NSSAI cannot be part of the authorized NSSAI, if the S-NSSAI(s) are in the Pending NSSAI in the AMF 70, the AMF 70 can extract the S-NSSAI(s) from the authorized NSSAI received from the NSSF 76.

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

[0087] For example, the AMF 70 may determine the authorized NSSAI (e.g., the contents of the authorized NSSAI) based on at least one of the Pending NSSAI (e.g., the S-NSSAI(s) in the Pending NSSAI) and the authorized NSSAI received from the NSSF 76 (e.g., the S-NSSAI(s) in the received authorized 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 Authorized NSSAI received from NSSF 76, AMF 70 can construct an Authorized NSSAI that includes S-NSSAI D. AMF 70 can then send a registration accept message that includes the Authorized NSSAI that includes S-NSSAI D.

[0089] The registration acceptance message may be any other NAS message.

[0090] The second example of the first aspect can be modified as the third modification of the first example of the first aspect.

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

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

[0093] For example, in step 2 of Figure 1, AMF70 may determine whether to include a Pending NSSAI (e.g., S-NSSAI(s) within the Pending NSSAI) in the Nnssf_NSSelection_Get message based on the network operator's configuration or policy within AMF70.

[0094] For example, in step 2 of Figure 1, the AMF 70 may use the network operator's configuration or policy within the AMF 70 to determine which network slice(s) (or S-NSSAI(s)) of the Pending NSSAI should be included in the Nnssf_NSSelection_Get message to the NSSF 76.

[0095] Modification 5 of the first example of the first aspect: In one example, if UE 3 registers with AMF 70 via another access, AMF 70 sends two Pending NSSAIs to NSSF 76, i.e., one Pending NSSAI for each access type. The Pending NSSAI for an access type includes the S-NSSAI(s) that are the subject of the NSSAI and are requested via that access type. When NSSF 76 receives a separate Pending NSSAI for each access type, NSSF 76 takes both Pending NSSAIs into account to determine the authorized NSSAI for each access type. NSSF 76 can also determine which AMF can process the authorized NSSAI, the Pending NSSAI for each access type. The NSSF 76 sends an Nnssf_NSSelection_Get response message including at least one of the following: a list of AMF sets or AMF addresses, an allowed NSSAI for one access type, a mapping of the allowed NSSAI, an allowed NSSAI for another access type, a mapping of the allowed NSSAI, an NSI ID(s), an NRF(s), a list of rejections (S-NSSAI(s), cause value(s)), a configured NSSAI for the serving PLMN, a mapping of the configured NSSAI, a pending NSSAI for one access, a pending NSSAI for another access, a mapping of the pending NSSAI for one access, and a mapping of the pending NSSAI for another access.

[0096] If the S-NSSAI(s) in the Pending NSSAI of any access are not supported in the AMF set or list of AMF sets selected by the NSSF 76, the NSSF 76 places the S-NSSAI(s) from the Pending NSSAI into a Rejected NSSAI for that access (e.g., at least one of any access), along with the reason why it was rejected. The reason may indicate, for example, that the Pending NSSAI is not supported in the selected AMF or TAI processed by the AMF 70. When the AMF 70 receives a Pending S-NSSAI rejected by the NSSF 76 (e.g., a Rejected NSSAI received from the NSSF 76), the AMF 70 removes the S-NSSAI from the Pending NSSAI list (e.g., the AMF 70's Pending NSSAI) and sends it to the UE 3 in a Rejected NSSAI or an Extended Rejected NSSAI together with a rejection cause (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 value). When the UE 3 receives the Rejected NSSAI in a NAS message from the AMF 70, the UE 3 removes the S-NSSAI from the Pending NSSAI list (e.g., the UE 3's Pending NSSAI) and acts according to the received cause value.

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

[0098] The NSSAA procedure of S-NSSAI1 then proceeds.

[0099] In this case, the UE 3 and the AMF 70 have a first Pending NSSAI for one access, which includes S-NSSAI1.

[0100] Then, while the NSSAA procedure for S-NSSAI1 is ongoing, UE3 also performs a second registration procedure by sending a second Registration Request message including a second Requested NSSAI (e.g., a second Requested NSSAI for another access) via another access to the same AMF 70. The second Requested NSSAI may include S-NSSAI2. S-NSSAI2 is the subject of the NSSAA procedure.

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

[0102] In this case, the UE 3 and AMF 70 also have a second Pending NSSAI for another access, including S-NSSAI2.

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

[0104] If the second registration procedure requires the AMF reallocation procedure of Section 4.2.2.2.3 of 3GPP TS 23.502 [3], the AMF 70 may send an Nnssf_NSSelection_Get message including a first Pending NSSAI and a second Pending NSSAI to the NSSF 76. The Nnssf_NSSelection_Get message may include at least one of a first Requested NSSAI for one access and a second Requested NSSAI for another access.

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

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

[0107] In addition, when NSSF76 receives an Nnssf_NSSelection_Get message, NSSF76 may determine an AMF set or a list of 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, the NSSF76 may discover an AMF(s) that can process 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, NSSF 76 may discover AMF(s) that can process S-NSSAI1 and S-NSSAI2. NSSF 76 may include the discovered AMF(s) in an AMF set or may include the addresses of the discovered AMF(s) in a list of AMF addresses.

[0110] In addition, when the NSSF76 receives an Nnssf_NSSelection_Get message, the NSSF76 may take into account both the first Pending NSSAI and the second Pending NSSAI to determine a first authorized NSSAI for one access and a second authorized NSSAI for the other access.

[0111] In addition, when the NSSF76 receives an Nnssf_NSSelection_Get message, the NSSF76 may determine a first authorized NSSAI for one access and a second authorized 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 authorized NSSAI and the second authorized NSSAI, the NSSF76 may extract the S-NSSAI1 included in the first Pending NSSAI and the S-NSSAI2 included in the second Pending NSSAI from at least one of the first authorized NSSAI and the second authorized NSSAI.

[0113] The NSSF 76 then 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 authorized NSSAI for one access, a mapping of the first authorized NSSAI, a second authorized NSSAI for another access, a mapping of the second authorized NSSAI, NSI ID(s), NRF(s), a list of reject (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) in the Pending NSSAI of any access are not supported by the AMF(s) in the AMF set or list of AMF addresses selected by the NSSF 76 (e.g., if the NSSF 76 is unable to determine the appropriate AMF set or appropriate list of AMF addresses for the first and second Pending NSSAIs), the NSSF 76 may include the S-NSSAI(s) in the Pending NSSAI in the Rejected NSSAI of that access (e.g., at least one of the one access and the other access), along with the reason why it was rejected. The reason may, for example, indicate that the Pending NSSAI(s) (e.g., the S-NSSAI(s) in the Pending NSSAI) are not supported in the selected AMF or TAI(s) processed by the AMF.

[0115] For example, if the S-NSSAI(s) in the Pending NSSAI of any access (e.g., both one access and another access) are not supported by the AMF(s) in the AMF set or list of AMF addresses selected by the NSSF 76 (e.g., if the NSSF 76 cannot determine an appropriate AMF set or an appropriate list of AMF addresses for the first and second Pending NSSAIs), the NSSF 76 may place the S-NSSAI(s) in the first and second Pending NSSAIs in the Rejected NSSAI. For example, the NSSF 76 may place the S-NSSAI(s) in at least one of the first Rejected NSSAI for one access and the second Rejected NSSAI for another access. The first Rejected NSSAI and the second Rejected NSSAI may be one (or a common) Rejected NSSAI.

[0116] Further, the NSSF76 may set a cause or cause value indicating that the S-NSSAI(s) in at least one of the first Pending NSSAI and the second Pending NSSAI are not supported by the selected AMF or are not supported in the TAI(s) processed by the selected AMF (e.g., the TA(s) indicated by the TAI(s)).

[0117] The NSSF 76 may send an Nnssf_NSSelection_Get response message that includes at least one of the first Rejection NSSAI, the second Rejection NSSAI, and a cause value. The Nnssf_NSSelection_Get response message may include other parameters as described above.

[0118] For example, if the S-NSSAI(s) in the first Pending NSSAI are not supported by the AMF(s) in the AMF set or the AMF in the list of AMF addresses selected by the NSSF76, and if the S-NSSAI(s) in the second Pending NSSAI are supported by the AMF in the AMF set or the AMF in the list of AMF addresses selected by the NSSF76, the NSSF76 may place the S-NSSAI(s) in the first Pending NSSAI in a first Denied NSSAI for one access. The NSSF76 may place the S-NSSAI(s) in the second Pending NSSAI in a second Allowed NSSAI for another access.

[0119] Further, the NSSF76 may 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) processed by the selected AMF (e.g., the TA(s) indicated by the TAI(s)).

[0120] The NSSF 76 may send an Nnssf_NSSelection_Get response message that includes at least one of the first rejected NSSAI, the cause value, and the second accepted NSSAI. The Nnssf_NSSelection_Get response message may include other parameters as described above.

[0121] If the AMF70 receives at least one of the first authorization NSSAI for one access and the second authorization NSSAI for another access, the AMF70 may send at least one of the first authorization NSSAI for the one access and the second authorization NSSAI for the other access to the UE3. For example, the AMF 70 may send a first authorization NSSAI for one access to the UE 3 via one access.

[0122] For example, the AMF 70 may send a second authorization NSSAI for the different access to the UE 3 via the different access.

[0123] If the AMF70 receives at least one of the first denial NSSAI for one access and the second denial NSSAI for another access, the AMF70 may send at least one of the first denial NSSAI for the one access and the second denial NSSAI for the other access to the UE3.

[0124] For example, the AMF 70 may send a first rejection NSSAI for one access to the UE 3 via one access.

[0125] For example, the AMF 70 may send a second rejection NSSAI for the other access to the UE 3 via the other access.

[0126] Second example of the first aspect: A second example of the first aspect discloses a method in which, when the UE 3 holds a Pending NSSAI, the UE 3 sends the Pending NSSAI to the RAN 5 and the AMF 70. The AMF 70 then sends an Nnssf_NSSelection_Get message to the NSSF 76, which includes the Pending NSSAI received from the UE 3 in addition to the Requested NSSAI, to discover an appropriate AMF to serve the UE 3.

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

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

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

[0130] Step 1. UE 3 sends a Radio Resource Control (RRC) Setup Request message to RAN 5. The trigger for the RRC Setup Request message at UE 3 may be that an application at UE 3 requests to establish new PDU session(s) with S-NSSAI(s) that have not yet been requested for 5GS. For example, UE 3 in CM-IDLE state may send the RRC Setup Request message. For example, UE 3 may send the RRC Setup Request message after the registration procedure while the NSSAA procedure has not yet been initiated by the AMF.

[0131] Step 2. The RAN 5 sends an RRC setup message to the UE 3. For example, if the RAN 5 receives an RRC setup request message, the RAN 5 can send an RRC setup message.

[0132] Step 3. The UE 3 sends an RRC Setup Complete message to the RAN 5, including the registration AMF, 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), Requested NSSAI, Pending NSSAI, and a Non-Access-Stratum (NAS) container. The NAS container includes a registration request message. The registration request message within the NAS container includes the Requested NSSAI and Pending NSSAI. If the UE 3 has the Pending NSSAI stored in its storage, the UE 3 includes the Pending NSSAI in both the RRC Setup Complete message and the registration request message.

[0133] For example, the UE 3 may include the Pending NSSAI that the UE 3 holds in step 0 in both the RRC Setup Complete message and the Registration Request message.

[0134] For example, the UE 3 may transmit 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 an RRC Setup Complete message and a Registration Request message.

[0136] The UE3 may send a Pending NSSAI (e.g., S-NSSAI(s) included in the Pending NSSAI) for registration via the AMF reallocation procedure.

[0137] The Pending NSSAI (e.g., S-NSSAI(s) 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 via 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 the UE 3 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 the UE 3 includes the Pending NSSAI in the Registration Request message, the UE 3 may or may not include the Pending NSSAI in the RRC Setup Complete message.

[0139] For example, when the UE 3 receives an RRC setup message, the UE 3 may send an RRC setup complete message.

[0140] Step 4. When the RAN 5 receives an RRC Setup Complete message from the UE 3, if the RAN 5 cannot reach the AMF 70 indicated in the Registered AMF in the received RRC Setup Complete message, it checks both the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI to discover the AMF. This may occur if the UE 3 moves to another PLMN before the NSSAA procedure is initiated by the AMF 70 in the previous PLMN. For example, the RAN 5 can discover the AMF 70 using both the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI. For example, the RAN 5 can discover the AMF 70 using at least one of the S-NSSAI(s) in the Requested NSSAI and the S-NSSAI(s) in the Pending NSSAI.

[0141] Otherwise, the RAN 5 discovers the AMF 70 based on the received registered AMF in the RRC setup complete message.

[0142] The RAN 5 sends an Initial UE message including the registration request message received from the UE 3 in step 3 to the AMF 70.

[0143] The initial UE message may include the Pending NSSAI. For example, the initial UE message may include the Pending NSSAI received from UE 3 in step 3.

[0144] The initial UE message may include the Requested NSSAI. For example, the initial UE message may include the Requested NSSAI received from UE 3 in step 3.

[0145] For example, when RAN5 receives an RRC setup complete message, RAN5 may 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 Section 4.2.2.2.3 of the Registration with AMF Reassignment Procedure of 3GPP TS 23.502 [3]. For example, only a part of steps 2 to 3c may be performed.

[0148] Step 6. The AMF 70 sends an Nnssf_NSSelection_Get message including the Requested NSSAI and the Pending NSSAI to the NSSF 76. The Requested NSSAI is retrieved by the AMF 70 by copying it from the Registration Request message received from the UE 3 via the RAN 5 in step 4. The Pending NSSAI is retrieved by the AMF 70 by copying it from the Registration Request message received from the UE 3 via the RAN 5 in step 4.

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

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

[0151] The AMF 70 may perform step 6 in the same manner as step 2 of FIG. 1 using at least one of the received Requested NSSAI and the received Pending NSSAI.

[0152] Step 7. The NSSF 76 sends an Nnssf_NSSelection_Get response message containing the list of AMF sets or AMF addresses and the allowed NSSAIs to the AMF 70. The NSSF 76 takes into account the received Requested NSSAI and the received Pending NSSAI to discover the list of AMF sets or AMF addresses.

[0153] The NSSF 76 can discover or determine the AMF set or list of AMF addresses in the same manner as in the first example of the first aspect.

[0154] The NSSF 76 may discover or determine the AMF set or list of AMF addresses in the same manner as step 3 of the first example of the first aspect.

[0155] Step 8. Steps 5 to 8 are performed as described in Section 4.2.2.2.3 of 3GPP TS 23.502 [3] for Registration with AMF Re-allocation. For example, some of steps 5 to 8 may be performed.

[0156] In one example, in step 7a of case (A) of the registration via AMF reallocation procedure in section 4.2.2.2.3 of 3GPP TS 23.502 [3], the initial AMF (e.g., AMF 70) may include the Pending NSSAI in a Namf_Communication_N1MessageNotify message. Upon receiving the 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 may initiate an NSSAA procedure for each S-NSSAI present in the received Pending NSSAI. For example, the target AMF may initiate an NSSAA procedure for the S-NSSAI(s) present in the received Pending NSSAI. This example process 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 re-allocation in section 4.2.2.2.3 of 3GPP TS 23.502 [3], the initial AMF (e.g., AMF 70) may include the Pending NSSAI in a Reroute NAS message (i.e., a Reroute NAS request message) and send the Reroute NAS message to the NG-RAN (e.g., RAN 5). Upon receiving the Reroute NAS message including the Pending NSSAI in the NG-RAN, the NG-RAN may select a target AMF (e.g., the target AMF may be the AMF discovered or selected by the NSSF 76 in at least one of steps 5 to 7) using at least one of the Pending NSSAI and the Authorized NSSAI. The Authorized NSSAI may be included in the Reroute NAS message or may be stored by the NG-RAN. When the NG-RAN receives a reroute NAS message including a Pending NSSAI, the NG-RAN sends an Initial UE message including the Pending NSSAI received from the Initial AMF to the target AMF in step 7a of case (B). When the target AMF receives the Initial UE message including the Pending NSSAI, the target AMF may initiate an NSSAA procedure for each S-NSSAI present in the received Pending NSSAI. For example, the target AMF may initiate an NSSAA procedure for S-NSSAI(s) present in the received Pending NSSAI. This example process may be applied to the first example of the first aspect.

[0158] According to a second example of the first aspect, for example, the UE 3 includes the Pending NSSAI in at least one of the RRC Setup Complete message and the Registration Request message, and the NSSF 76 takes the Pending NSSAI into account to discover the AMF set or the list of AMF addresses.

[0159] According to the second example of the first aspect, the above-mentioned problems can be solved. For example, the second example of the first aspect can solve a problem in which, after an NSSAA procedure, all service(s) using S-NSSAI(s) newly added to the authorized NSSAI cannot be provided to the UE because the newly selected AMF cannot process or support the S-NSSAI(s). For example, the second example of the first aspect can solve a problem such as significant service degradation of all service(s) using network slicing in 5GS.

[0160] Modification 1 of the second example of the first aspect: If UE3 is in CM-CONNECTED state (e.g., UE3 is in CM-CONNECTED state at step 0), for example, an NSSAA procedure is in progress immediately after the previous registration procedure, and the following changes are required in the call flow (or process) of Figure 2: -Steps 1 and 2 are deleted. The RRC Setup Complete message in step 3 is replaced with an RRC UL information transfer message or an Up Link (UL) information transfer message containing a NAS container. The NAS container contains a registration request message. The registration request message in the NAS container contains the Requested NSSAI and the Pending NSSAI. The Initial UE message in step 4 is replaced with an Uplink NAS Transport message, which contains the Registration Request message received from UE3 in step 3.

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

[0162] Modification 2 of the second example of the first aspect: The network operator may have a configuration or policy regarding whether the network slice(s) (or S-NSSAI(s)) from the Pending NSSAI in the UE 3 need to be included by the UE 3 in the Pending NSSAI to the RAN 5 in the RRC Setup Complete message for AMF selection and / or whether the network slice(s) (or S-NSSAI(s)) need to be included by the UE 3 in the Pending NSSAI to the AMF 70 in the Registration Request message for AMF reallocation. Regarding the configuration or policy, a new rule in the UE policy (e.g., a new rule part of the UE Route Selection Policy (URSP) rule) may be defined and configurable by the network operator per UE granularity.

[0163] For example, in step 3 of Figure 2, UE3 may use the network operator's configuration or policy at UE3 when determining whether to include 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.

[0164] For example, in step 3 of FIG. 2, UE3 may determine, based on a network operator configuration or policy at UE3, whether to include a Pending NSSAI (e.g., S-NSSAI(s) within the Pending NSSAI) in at least one of an RRC Setup Complete message, a Registration Request message, and a UL Information Transfer message.

[0165] For example, in step 3 of FIG. 2, UE3 may use a network operator configuration or policy within UE3 to determine which network slice(s) (or S-NSSAI(s)) of the Pending NSSAI should be included in at least one of the RRC Setup Complete message, the Registration Request message, and the UL Information Transfer message.

[0166] Modification 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 UE 3 may add the S-NSSAI(s) in 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 may include the S-NSSAI(s) for which the UE 3 requests registration and the S-NSSAI(s) from the Pending NSSAI in the UE 3.

[0167] For example, if the UE 3 has a Pending NSSAI that includes the S-NSSAI1, the UE 3 may include the 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 UE 3 may not include the Pending NSSAI in at least one of the RRC Setup Complete message and the Registration Request message.

[0168] The RAN 5 may send a registration request message to the AMF 70, and the AMF 70 may send an Nnssf_NSSelection_Get message to the NSSF 76.

[0169] When the NSSF 76 receives the Nnssf_NSSelection_Get message, the NSSF 76 can find the AMF set or list of AMF addresses based on the received Requested NSSAI.

[0170] Modification 4 of the second example of the first aspect: In the second example, the same principle as in Variation 5 of the first example of the first aspect can be applied. For example, when an NSSAI is in progress via one access (e.g., UE 3 has a Pending NSSAI for one access) and UE 3 is in step 0 via another access (e.g., UE 3 is in the CM-IDLE state and holds a Pending NSSAI for another access), UE 3 can transmit the Pending NSSAI for the one access and the other access to RAN 5 using at least one of an RRC Setup Complete message, a Registration Request message, and an UL Information Transfer message. Upon receiving at least one of the messages, RAN 5 can transmit the Pending NSSAI to AMF 70 using at least one of an Initial UE message and an uplink NAS Transport message.

[0171] The AMF 70 can then execute the same process as in Variation 5 of the first example of the first embodiment.

[0172] System Overview FIG. 3 shows a schematic diagram of a mobile (cellular or wireless) telecommunications system 1 to which the above-described aspects can be applied.

[0173] The telecommunications system 1 represents a system overview capable of end-to-end communication, e.g., UEs 3 (or user equipment, "mobile devices", 3) communicating with other UEs 3 or service servers in a data network 20 via respective (R)AN nodes 5 and a core network 7.

[0174] The (R)AN node 5 supports any radio access including 5G Radio Access Technology (RAT), E-UTRA radio access technology, RATs beyond 5G, 6G RATs, and non-3GPP RATs, including Wireless Local Area Network (WLAN) technology defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0175] The (R)AN node 5 can be divided into a Radio Unit (RU), a Distributed Unit (DU), and a Centralized Unit (CU). In some aspects, each of the units can be connected to each other to construct the (R)AN node 5 by adopting an architecture defined by the Open RAN (O-RAN) Alliance, where these units are referred to as the O-RU, O-DU, and O-CU, respectively.

[0176] The (R)AN node 5 may be split into control plane functions and user plane functions. Furthermore, multiple user plane functions may be allocated to support communications. In some aspects, user traffic may be distributed across multiple user plane functions, with user traffic via each user plane function being aggregated to both the UE 3 and the (R)AN node 5. This split architecture is sometimes referred to as "dual connectivity" or "multi-connectivity."

[0177] The (R)AN node 5 may also support communications using satellite access. In some aspects, the (R)AN node 5 may support satellite access and terrestrial access.

[0178] The (R)AN node 5 can also be considered an access node for non-wireless access, which 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 may 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 control plane functions and user plane functions, among other functions. Each function within a logical node may be considered a network function. A network function may be provided to another node by adapting a Service Based Architecture (SBA).

[0180] By adapting network virtualization technology defined as European Telecommunications Standards Institute, Network Functions Virtualization (ETSI NFV), network functions can be deployed as distributed, redundant, stateless, and scalable, serving from several locations and several running instances in each location.

[0181] The core network 7 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0182] As is known, a UE 3 may move in and out of areas (i.e., radio cells) served by an (R)AN node 5 as the UE 3 moves within the geographic area covered by the telecommunications system 1. To track the UE 3 and facilitate 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 nodes 5 coupled to the core network 7. In some core networks, a Mobility Management Entity (MME) or a beyond-5G or 6G mobility management node may be used instead of the AMF 70.

[0183] The core network 7 also includes, among other things, 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 a UE 3 is roaming in a visited Public Land Mobile Network (PLMN), the home public land mobile network (HPLMN) of the UE 3 provides the roaming-out UE 3 with the UDM 75, and at least some of the functionality of the SMF 71, UPF 72, and PCF 73.

[0184] The UE 3 and each serving (R)AN node 5 are connected via an appropriate air interface (e.g., the so-called "Uu" interface, etc.). Adjacent (R)AN nodes 5 are connected to each other via appropriate (R)AN node 5 (e.g., the so-called "Xn" interface, etc.). Each (R)AN node 5 is also connected to nodes in the core network 7 (e.g., so-called core network nodes) via appropriate interfaces (e.g., the so-called "N2" / "N3" interface(s)). The core network 7 also provides a connection to a data network 20. The data network 20 can be the Internet, a public network, an external network, a private network, or an internal network of a PLMN. If the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), IP Multimedia Subsystem (IMS) services may be provided by that data network 20. The UE 3 can connect to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or unstructured data types.

[0185] The "Uu" interface may include the control plane of the Uu interface and the user plane of the Uu interface. The user plane of the Uu interface is responsible for carrying user traffic between the UE 3 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 over the physical connection.

[0186] The control plane of the Uu interface is responsible for establishing, modifying, and releasing the connection between the UE 3 and the serving (R)AN node 5. The control plane of the Uu interface may have a hierarchical structure with RRC, PDCP, RLC, and MAC sublayers over the physical connection.

[0187] For example, the following messages are communicated over the RRC layer to support AS signaling: RRC Setup Request Message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup Request message: -establishmentCause and ue-Identity, where ue-Identity may have the value of ng-5G-S-TMSI-Part1 or randomValue. RRC Setup Message: This message is sent from the (R)AN node 5 to the UE 3. In addition to the parameters disclosed by 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 the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by 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] The UE 3 and the AMF 70 are connected via an appropriate interface (such as a so-called N1 interface). The N1 interface is responsible for providing communication between the UE 3 and the AMF 70 to support NAS signaling. The N1 interface can 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 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 included together in the Registration Request message: -5GS registration type, ngKSI, 5GS mobile identity, non-current native NAS key set identifier, 5GMM capabilities, UE security capabilities, Requested NSSAI, last visited registration TAI, S1 UE network capabilities, uplink data status, PDU session status, MICO indication, UE status, additional GUTI, allowed PDU session status, UE usage configuration, 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 capability ID, requested mapping NSSAI, requested information, requested WUS assistance information, N5GC indication and requested NB-N1 DRX parameters. Registration Accept 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 also be included in the registration accept message: -5GS Registration Result, 5G-GUTI, Equivalent PLMN, TAI List, Allowed NSSAI, Rejected NSSAI, Configured NSSAI, 5GS Network Capability 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, Negotiate DRX Parameters, Non-3GPP NW Policy, EPS Bearer Context Status, Negotiate Extended DRX Parameters, T3447 Value, T3448 Value, T3324 Value, UE Radio Capability ID, UE Radio Capability ID Deletion Indication, Pending NSSAI, Cipher Key Data, CAG Information List, Truncated 5G-S-TMSI Configuration, Negotiate WUS Assistance Information, Negotiate NB-N1 Mode DRX Parameters, and Extended Rejected NSSAI. Registration 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 included together in the registration complete message: -SOR transparent container. -Authentication Request 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 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 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 taken 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 taken together in the Authentication Result message: -ngKSI, EAP Messages, 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 taken together in the Authentication Failure Message: -Authentication failure message identifier, 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 together in the authentication rejection message: -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 taken together in the service request message: -ngKSI, Service Type, 5G-S-TMSI, Uplink Data Status, PDU Session Status, Grant 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 taken together in the Service Acceptance Message: -PDU session status, PDU session reactivation result, PDU session reactivation result error cause, 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 taken together in the Service Rejection Message: -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 aspects of the present disclosure, the following parameters may be taken together in the Configuration Update Command message: -Configuration update indication, 5G-GUTI, TAI list, Allowed NSSAI, Service Area List, Network Full 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 Delete 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 taken together in the Configuration Update Complete message: - Set Update Complete message identification information.

[0189] User Equipment (UE) FIG. 4 is a block diagram illustrating the main components of a mobile device 3 (UE 3). As shown, the UE 3 includes a transceiver circuit 31 operable to transmit and receive signals to and from connected node(s) via one or more antennas 32. The UE 3 may also include a user interface 34 for inputting and outputting information from and to the outside. Although not necessarily shown in the figure, the UE 3 may have all the usual functions of a conventional mobile device, which may be provided by any one or any combination of hardware, software, and firmware, as needed. The software may be pre-installed in memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The controller 33 controls the operation of the UE 3 in accordance with 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 communications control module 362 (using its transceiver control module 3621) is responsible for processing (generating / sending / receiving) signaling and uplink / downlink data packets between the UE 3 and other nodes, such as the (R)AN node 5 and the AMF 70. Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for the UE 3). The controller 33 interoperates with one or more Universal Subscriber Identity Modules (USIMs) 35. If multiple USIMs 35 are equipped, the controller 33 may activate only one USIM 35 or may activate multiple USIMs 35 simultaneously.

[0190] The UE 3 may, for example, support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

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

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

[0193] The UE 3 may be, for example, an item of information and communications equipment (such as information and communications equipment such as electronic computers and related equipment, communications and related equipment, electronic components, etc.).

[0194] The UE3 may be, for example, a refrigerator, a refrigerator application product, an item of goods and / or service industry equipment, a vending machine, an automated service machine, an office machine or appliance, a consumer electronic device and an electronic device (e.g., consumer electronic device such as audio equipment, video equipment, speakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, electronic fans or related equipment, vacuum cleaners, etc.).

[0195] The UE 3 may be, for example, an electrical application system or device (eg, an electrical 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, lighting fixture, measuring instrument, analyzer, tester, or surveying or sensing equipment (such as a smoke alarm, a motion sensor, a radio frequency tag, etc.), a watch or clock, inspection equipment, optical equipment, medical equipment and / or systems, a weapon, an item of cutlery, a hand tool, etc.

[0197] UE3 may be, for example, a wireless-equipped personal digital assistant or related equipment (e.g., a wireless card or module designed to be attached to or inserted into another electronic device (e.g., a personal computer, electrical measuring instrument)).

[0198] The UE 3 may be part of a device or system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below with respect to the "Internet of Things (IoT)."

[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 other communicating devices. IoT devices may include automated machines 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 extended periods of time. IoT devices may be implemented as part of (generally) stationary equipment. IoT devices may also be embedded in non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0200] It will be understood that IoT technology may be implemented on any communication device that can connect to a communication network to send / receive data, regardless of whether such communication device is controlled by human input or software instructions stored in memory.

[0201] It will be appreciated that an IoT device may also be referred to as a Machine-Type Communication (MTC) device or a Machine-to-Machine (M2M) communication device or a Narrow Band (NB)-IoT UE. It will be appreciated that a UE 3 may support one or more IoT or MTC applications.

[0202] The UE 3 may be a smartphone or a wearable device (e.g., smart glasses, a smart watch, a smart ring, or a hearable device).

[0203] The UE3 may be a car, a connected car, an autonomous car, a vehicle device, a motorcycle, or a V2X (Vehicle to Everything) communication module (e.g., 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 illustrating the main components of an exemplary (R)AN node 5, e.g., a base station (eNB in ​​LTE, gNB in ​​5G, later 5G base station, 6G base station). As shown, the (R)AN node 5 includes transceiver circuitry 51 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 52 and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 53. A controller 54 controls operation of the (R)AN node 5 in accordance with software stored in 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 (RMD). The software includes, among other things, an operating system 551 and a communications control module 552 having at least a transceiver control module 5521.

[0205] The communications control module 552 (using its transceiver control sub-module) is responsible for handling (generating / sending / receiving) signaling (e.g., directly or indirectly) 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. The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connectivity with the core network 7 (for a particular UE 3), in particular related to connection establishment and maintenance (e.g., of RRC connection establishment and other RRC messages), Next Generation Application Protocol (NG Application Protocol (NGAP)) messages (i.e., messages according to the N2 reference point) and Xn application protocol (XnAP) messages (i.e., messages according to the Xn reference point), etc. Such signaling may also include, for example, broadcast information (e.g., of master information and system information) in the transmit case.

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

[0207] The (R)AN node 5 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0208] System overview of (R)AN Node 5 based on O-RAN architecture FIG. 6 illustrates schematically an (R)AN node 5 based on an O-RAN architecture to which aspects of the (R)AN node 5 are 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 aspects, each unit can be combined. For example, the RU 60 can be combined with the DU 61 as a combined / combined unit, and the DU 61 can be combined with the CU 62 as another combined / combined unit. Any functionality in the description of a unit (e.g., one of the RU 60, DU 61, and CU 62) can be implemented in the combined / combined unit. Furthermore, 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 the control plane function in the (R)AN node 5. The CU UP has the user plane function 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 a DU 61 via an appropriate interface (e.g., a so-called "fronthaul", "open fronthaul", "F1" interface, etc.). Each DU 61 is connected to a CU 62 via an appropriate interface (e.g., a so-called "midhaul", "open midhaul", "E2" interface, etc.). Each CU 62 is also connected to a node in the core network 7 (e.g., a so-called core network node) via an appropriate interface (e.g., a so-called "backhaul", "open backhaul", "N2" / "N3" interface(s), etc.). Furthermore, the user plane part of the DU 61 may be connected to the core network 7 via an appropriate interface (e.g., a so-called "N3" interface(s)).

[0211] Depending on the functionality divided among the RU 60, DU 61, and CU 62, each unit provides a portion of the functionality provided by the (R)AN node 5. For example, the RU 60 may provide functionality for communicating with the UE 3 over the air interface, the DU 61 may provide functionality for supporting the MAC and RLC layers, and the CU 62 may provide functionality for supporting the PDCP, SDAP, and RRC layers.

[0212] Radio Unit (RU) FIG. 7 is a block diagram illustrating the main components of an exemplary RU 60, e.g., the RU portion of a base station (eNB in ​​LTE, gNB in ​​5G, later 5G base station, 6G base station). As shown, the RU 60 includes a transceiver circuit 601 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 602 and to transmit and receive signals to and from other network nodes or units (directly or indirectly) via a network interface 603. A controller 604 controls the operation of the RU 60 according to software stored in memory 605. The software may be pre-installed in the memory 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 6051 and a communications control module 6052 having at least a transceiver control module 60521.

[0213] The communications control module 6052 is responsible for handling (generating / sending / receiving) signaling (e.g., directly or indirectly) between the RU 60 (using its transceiver control sub-module) and other nodes or units, such as a UE 3, another RU 60, and a DU 61. The signaling may include, for example, appropriately formatted signaling messages relating to the radio connection and connectivity with the RU 60 (for a particular UE 3), particularly the MAC and RLC layers.

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

[0215] The RU 60 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

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

[0217] Distributed Unit (DU) FIG. 8 is a block diagram illustrating the main components of an exemplary DU 61, e.g., a DU section of a base station (eNB in ​​LTE, gNB in ​​5G, later 5G base station, 6G base station). As shown, the device includes a transceiver circuit 611 operable to transmit signals to and receive signals from other nodes or units (including RU 60) via a network interface 612. A controller 613 controls the operation of the DU 61 in accordance with software stored in memory 614. The software may be pre-installed in 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 communications control module 6142 having at least a transceiver control module 61421. The communication control module 6142 (using its transceiver control module 61421) is responsible for handling (generating / sending / receiving) signaling between the DU 61 and other nodes or units, such as the RU 60 and other nodes and units.

[0218] The DU 61 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0219] As mentioned above, the RU 60 can be integrated / combined with the DU 61 or the CU 62 as an integrated / combined unit. Any function in the description of the DU 61 can be implemented in one of the above integrated / combined units.

[0220] Centralized Unit (CU) FIG. 9 is a block diagram illustrating the main components of an exemplary CU 62, e.g., the CU portion of a base station (eNB in ​​LTE, gNB in ​​5G, later 5G base station, 6G base station). As shown, the device includes a transceiver circuit 621 operable to transmit signals to and receive signals from other nodes or units (including the DU 61) via a network interface 622. A controller 623 controls the operation of the CU 62 in accordance with software stored in 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 (RMD). The software includes, among other things, an operating system 6241 and a communications control module 6242 having at least a transceiver control module 62421. The communications control module 6242 (using its transceiver control module 62421) is responsible for handling (generating / sending / receiving) signaling between the CU 62 and other nodes or units, such as the DU 61 and other nodes and units.

[0221] The CU 62 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0222] As mentioned above, the CU 62 can be integrated / combined with the DU 61 as an integrated / combined unit. Any functionality described for the CU 62 can be implemented in the integrated / combined unit.

[0223] AMF 10 is a block diagram illustrating the main components of the AMF 70. As shown, the device includes a transceiver circuit 701 operable to transmit signals to and receive signals from other nodes (including UEs 3, NSSAAFs) via a network interface 702. A controller 703 controls the operation of the AMF 70 in accordance with software stored in memory 704. The software may be pre-installed in memory 704 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 7041 and a communications control module 7042 having at least a transceiver control module 70421. The communications control module 7042 (using its transceiver control module 70421) is responsible for handling (generating / sending / receiving) signaling between the AMF 70 and other nodes, such as the UE 3 (e.g., via the (R)AN node 5) and other core network nodes (including core network nodes in the UE 3's HPLMN when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for the UE 3).

[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 11 is a block diagram illustrating the main components of the PCF 73. As shown, the device includes a transceiver circuit 731 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 732. A controller 733 controls the operation of the PCF 73 in accordance with software stored in memory 734. The software may be pre-installed in the memory 734 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (e.g., a Removable Memory Device (RMD)). The software includes, among other things, an operating system 7341 and a communications control module 7342 having at least a transceiver control module 73421. The communications 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 in the UE 3's HPLMN when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted (e.g., HyperText Transfer Protocol (HTTP) restful methods based on service-based interfaces) signaling messages related to policy management procedures (for the UE 3).

[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 Non-Public Network (PNI-NPN). The PCF 7301 and PCF 7302 can have the same components as the PCF 73.

[0227] AUSF 12 is a block diagram illustrating the major components of the AUSF 74. As shown, the device 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 controller 743 controls the operation of the AUSF 74 in accordance with software stored in memory 744. The software may be pre-installed in the memory 744 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (e.g., a Removable Memory Device (RMD)). The software includes, among other things, an operating system 7441 and a communications control module 7442 having at least a transceiver control module 74421. The communications control module 7442 (using its transceiver control module 74421) is responsible for handling (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 in the UE 3's HPLMN when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP convenience methods based on service-based interfaces) related to policy management procedures (for the UE 3).

[0228] The AUSF 74 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0229] UDM FIG. 13 is a block diagram illustrating the main components of the UDM 75. As shown, the device includes a transceiver circuit 751 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 752. A controller 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 in the UE 3's VPLMN), when the UE 3 is roaming out. Such signaling may include, for example, appropriately formatted signaling messages (for UE 3) related to mobility management procedures (for example, HTTP convenience methods based on service-based interfaces).

[0230] The UDM 75 can support a Non-Public Network (NPN), which 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 illustrating the main components of the NSSF 76. As shown, the device includes a transceiver circuit 761 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 762. A controller 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 telecommunications 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 UE 3's VPLMN when the UE 3 is roaming out). Such signaling may include, for example, suitably formatted signaling messages (e.g., in an HTTP convenient manner based on a service-based interface) related to mobility management procedures (for the UE 3).

[0232] The NSSF 76 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated Non-Public Network (PNI-NPN).

[0233] The exemplary embodiments disclosed above may be described in whole or in part as follows, but are not limited thereto.

[0234] 5.15.5.2 Serving AMF selection supporting network slicing 5.15.5.2.1 Registration in a set of network slices When a UE registers to a PLMN via an access type, the UE: - the configured NSSAI for this PLMN, - have an authorized NSSAI for this PLMN and access type, or both; The UE shall provide the Requested NSSAI containing the S-NSSAI(s) corresponding to the network slice(s) to which the UE is attempting to register to the network at the AS layer and NAS layer under the conditions described in subclause 5.15.9, unless the UE has stored them in its Pending NSSAI.

[0235] Requested NSSAI If the UE has neither a configuration NSSAI nor an authorized NSSAI for the serving PLMN, a default configuration NSSAI; For example, if the UE does not have an authorized NSSAI for the access type of the serving PLMN, a configured NSSAI or a subset thereof, such as those described below: - the Authorized NSSAI for the access type for which the Requested NSSAI is being sent, or a subset thereof; or - one of the Authorized NSSAIs for the access type for which the Requested NSSAI is sent, or a subset thereof, plus one or more S-NSSAIs from the Configured NSSAIs not already included in the Authorized NSSAIs for the access type, as described below. NOTE 1: If the UE wishes to register only a subset of S-NSSAIs from the Configured or Allowed NSSAIs, e.g., to be able to register with several network slices to establish PDU sessions for several application(s), and the UE uses URSP rules (including the Network Slice Selection Policy (NSSP)) or UE local configurations as defined in clause 6.1.2.2.1 of TS 23.503

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

[0236] The subset of S-NSSAIs in the configured NSSAI provided in the Requested NSSAI consists of one or more S-NSSAI(s) in the configured NSSAI applicable to this PLMN, if any, for which no corresponding S-NSSAI already exists in the authorized NSSAIs for this PLMN's access type. 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 to a PLMN for which neither a configured nor an authorized NSSAI exists applicable to this PLMN, the S-NSSAI provided in the Requested NSSAI corresponds to the S-NSSAI(s) in the default configuration NSSAI, unless the UE has an HPLMN S-NSSAI for the established PDU session(s), in which case the HPLMN S-NSSAI(s) shall be provided in the mapping of the Requested NSSAI in the NAS Registration Request message and there is no corresponding VPLMN S-NSSAI in the Requested NSSAI. If the UE has been provided with NSSRG information along with the configured NSSAI, the UE shall include only the S-NSSAI(s) in the Requested NSSAI that share a common NSSRG, see Section 5.15.12.2.

[0237] When the UE registers to the PLMN via the access type, if the Requested NSSAI is based on the default configuration NSSAI, the UE shall also indicate this in the Registration Request message.

[0238] The UE shall include the Requested NSSAI in RRC connection establishment and establishment of connection to the N3IWF / TNGF (if applicable), as well as in NAS registration procedure messages subject to the conditions described in subclause 5.15.9. However, the UE shall not indicate any NSSAI in RRC connection establishment messages or initial NAS messages unless it has either a configured NSSAI for the corresponding PLMN, an authorized NSSAI for the corresponding PLMN and access type, or a default configured NSSAI. If the UE has 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 a corresponding VPLMN S-NSSAI. The (R)AN shall route NAS signaling between this UE and the selected AMF using the Requested NSSAI obtained during RRC connection establishment or connection to the N3IWF / TNGF. If the (R)AN cannot select an AMF based on the Requested NSSAI, it routes the NAS signaling to an AMF from the set of default AMFs. In the NAS signaling, if available, the UE provides a mapping of each S-NSSAI of the Requested NSSAI to the corresponding HPLMN S-NSSAI.

[0239] When a UE registers to a PLMN, if the UE did not include a Requested NSSAI or GUAMI for this PLMN while establishing a connection to the (R)AN, the (R)AN shall route all NAS signaling to / from this UE to / from the default AMF. Upon receiving the Requested NSSAI and 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 is sent to the default AMF.

[0240] When the AMF selected by the AN during the registration procedure receives a 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 5GC. As part of the registration procedure described in clause 4.2.2.2.2 of TS 23.502 [3] or as part of a 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 may query the UDM to obtain UE subscription information, including the subscribed S-NSSAI. -The AMF verifies whether the S-NSSAI(s) in the Requested NSSAI or the S-NSSAI(s) received from the SMF+PGW-C are authorized based on the subscribed S-NSSAI (to identify the subscribed S-NSSAI, the AMF may use the mapping to the HPLMN S-NSSAI provided by the UE in the NAS message for each S-NSSAI of the Requested NSSAI). -If the UE context in the AMF does not yet contain an authorized NSSAI for the corresponding access type, the AMF queries the Network Slice Selection Function (NSSF) (see (B) below for further processing), unless the AMF is authorized to determine whether it can serve the UE based on the configuration in this AMF (see (A) below for further processing). The IP address or Fully Qualified Domain Name (FQDN) of the NSSF is configured locally in the AMF. Note 2: The configuration within the AMF depends on the operator's policy. -If the UE context in the AMF already includes an authorized NSSAI of the corresponding access type, the AMF is allowed to determine whether to serve the UE based on this AMF configuration (see (A) below for subsequent processing). The AMF or NSSF may have previously subscribed to network data analysis relating to slice load levels and / or observed service experience and / or variance analysis for a network slice from the NWDAF, optionally for a region of interest consisting of one or more TAIs. If the AMF subscribes to the analysis, the AMF may determine that it cannot serve the UE based on the received analysis (see (A) below). If the AMF subscribes to notifications about changes in availability information for a network slice or network slice instance from the NSSF, which optionally indicates a list of supported TAIs, it may determine that it cannot serve the UE after a restriction notification is received (see (A) below). If the AMF does not subscribe to notifications about changes in availability information from the NSSF, the NSSF may take the analysis information into account when the AMF queries the NSSF (see (B) below). Note 3: The configuration within the AMF depends on the operator's policy.

[0241] (A) Depending on the implementation of the above-mentioned configuration, the AMF can determine whether it can serve the UE, and the following is performed: 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 Requested NSSAI (in the CM-IDLE state) or the HPLMN S-NSSAI(s) in the mapping of the HPLMN S-NSSAI(s) received from the SMF+PGW-C (in the CM-CONNECTED state). The AMF then considers the derived value(s) as the Requested NSSAI. Between PLMNs 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. The AMF then considers the derived value(s) as the Requested NSSAI. The AMF checks whether it can serve all S-NSSAI(s) from the Requested NSSAI(s) present in the subscribed S-NSSAI (potentially using configuration for mapping S-NSSAI values ​​between the HPLMN and the serving PLMN) or whether it can serve all S-NSSAI(s) marked as default in the subscribed S-NSSAI if the Requested NSSAI(s) were not provided or none of the S-NSSAI(s) in the Requested NSSAI(s) were allowed, i.e., they do not match any of the subscribed S-NSSAI(s) or are not available in the tracking area of ​​the current UE (see section 5.15.3). -If the AMF subscribes to network data analysis related to slice load levels and / or observed service experience and / or dispersion analysis of network slices from the NWDAF, or if the AMF receives network slice restrictions from the NSSF that apply 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) in the Requested NSSAI. If the AMF can serve the S-NSSAI in the Requested NSSAI, the AMF remains the serving AMF for the UE. The Allowed NSSAI then consists of the list of S-NSSAI(s) in the Allowed Requested NSSAI based on the Subscribed S-NSSAI and / or the list of S-NSSAI(s) for the serving PLMN mapped to the HPLMN S-NSSAI(s) provided in the mapping of the Allowed Requested NSSAI based on the Subscribed S-NSSAI, or, if neither the Requested NSSAI nor the mapping of the Requested NSSAI is provided or none of the S-NSSAIs in the Requested NSSAI is allowed, all the subscribed S-NSSAI(s) marked as default in the Subscribed S-NSSAI and all the subscribed S-NSSAIs taking into account the availability of network slice instances as described in Section 5.15.8 that can serve the S-NSSAI(s) in the Allowed NSSAI within the tracking area of ​​the current UE in addition to any network slice instance restrictions for the S-NSSAI(s) in the Allowed NSSAI provided by the NSSF. If the AMF receives NSSRG information for a subscribed S-NSSAI as part of the UE subscription information, the AMF shall include only the allowed NSSAIs-NSSAIs, all of which share a common NSSRG (see clause 5.15.12). If at least one S-NSSAI in the Requested NSSAI is not available in the current UE's tracking area, 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) values.If the Requested NSSAI is not provided, or if the mapping of the S-NSSAI in 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 a default configuration NSSAI, the AMF may also determine the configuration NSSAI for the serving PLMN and, if applicable, the associated mapping of the configuration NSSAI to the HPLMN S-NSSAI based on the subscribed S-NSSAI(s) and the operator's configuration, so that these can be configured in the UE. Then, perform step (C). Otherwise, the AMF queries the NSSF (see (B) below).

[0242] (B) If necessary as above, the AMF needs to query the NSSF, which does the following: - The AMF receives the Requested NSSAI, the 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 the subject of the 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 a registration request message received in the CM-CONNECTED state, where the S-NSSAI is the subject of the NSSAI), the default NSSAI indication, the mapping of the Requested NSSAI to the HPLMN S-NSSAI, the subscribed S-NSSAI (with an indication if marked as the default S-NSSAI), the NSSRG information (if provided by the UDM, see section 5.15.12), any authorized NSSAIs it has for other access types (including the mapping to the HPLMN S-NSSAI), and the PLMN of the SUPI. Query the NSSF with the ID and the UE's current tracking area. Based on this information, local configuration, and other locally available information including RAN capabilities within the UE's current tracking area, or network slice instance load level information provided by the NWDAF, the NSSF: -Verify which S-NSSAI(s) in the Requested NSSAI are allowed based on comparing the subscribed S-NSSAI with the S-NSSAI in the mapping of the Requested NSSAI to the HPLMN S-NSSAI. If the Requested NSSAI was not provided or if an S-NSSAI from the Requested NSSAI is not allowed, i.e., not present in the subscribed S-NSSAI or unavailable, for example, in the current UE's tracking area, consider the S-NSSAI(s) marked as default in the subscribed S-NSSAI. If NSSRG information is provided, the NSSF selects only S-NSSAIs that share a common NSSRG (see clause 5.15.12). -If the AMF does not subscribe to notifications about changes in network slice or network slice instance availability information from the NSSF, and the NSSF subscribes to network data analysis related to slice load levels and / or observed service experience and / or variance analysis of the network slice from the NWDAF, the NSSF may use the analysis information to determine a list of S-NSSAI(s) within (network slice instance(s) and) allowed NSSAI(s) to serve the UE. - Selecting network slice instance(s) to serve the UE. If multiple network slice instances within the UE's tracking area can serve a given S-NSSAI, based on the operator's configuration, the NSSF can select one of them to serve the UE, or the NSSF can postpone the selection of the network slice instance until an NF / service within the network slice instance needs to be selected. -Determine a target AMF set to be used to serve the UE, or a list of candidate AMF(s) based on the configuration, possibly after querying the NRF. NOTE 4: If the target AMF(s) returned by 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 handover the UE to a cell in another TA as described in clause 5.3.4.3.3. - Determine the allowed NSSAI(s) for the applicable access type, which consists of the list of S-NSSAI(s) in the Requested NSSAI that are allowed based on the subscribed S-NSSAI and / or the list of S-NSSAI(s) for the serving PLMN that are mapped to the HPLMN S-NSSAI provided in the mapping of the Requested NSSAI that are allowed based on the subscribed S-NSSAI, or, if neither the Requested NSSAI nor the mapping of the Requested NSSAI is provided or none of the S-NSSAIs in the Requested NSSAI are allowed, all S-NSSAI(s) marked as default in the subscribed S-NSSAI and all S-NSSAIs that can serve the S-NSSAI(s) in the allowed NSSAI in the tracking area of ​​the current UE, taking into account the availability of network slice instances as described in Section 5.15.8. If NSSRG information applies, the NSSF selects only S-NSSAIs that share a common NSSRG (see Section 5.15.12). - If necessary, also determine the mapping of each S-NSSAI of the Authorized NSSAI to the Subscribed S-NSSAI(s). Based on operator configuration, the NSSF may determine the Network Repository Function (NRF)(s) to be used to select the Network Function (NF) / service(s) within the selected network slice instance(s). - Additional processing to determine the mapping to the Authorized NSSAI(s) and the Subscribed S-NSSAI in roaming scenarios, as described in Section 5.15.6. -If the Requested NSSAI and pending NSSAI are not provided, or if the Requested NSSAI or pending NSSAI includes 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 a default configuration NSSAI indication is received from the AMF, the NSSF based on the subscribed S-NSSAI(s) and operator configuration may also determine the configuration NSSAI for the serving PLMN and, if applicable, the associated mapping of the configuration NSSAI to the HPLMN S-NSSAI, so that these can be configured in the UE. If at least one S-NSSAI in the Requested NSSAI or Pending NSSAI is not available in the current UE's Tracking Area, the NSSF may provide a Target NSSAI, as described in Section 5.3.4.3.3, with the aim of enabling the NG-RAN to redirect the UE to a cell in a TA of another frequency band that supports a network slice that is not available in the current TA. If the S-NSSAI in the -pending NSSAI is not supported by the TA or is not available in the PLMN, the NSSF includes the S-NSSAI in the Rejected NSSAI with the cause S-NSSAI is not supported by the TA or S-NSSAI is not supported by the PLMN. The NSSF returns to the current AMF the allowed NSSAIs for the applicable access type, the mapping of each S-NSSAI of the allowed NSSAIs to the subscribed S-NSSAIs, if determined, and a list of candidate AMF(s) based on the target AMF set or configuration. The NSSF may return the NRF(s) used to select the NF / service in the selected network slice instance(s) and the NRF(s) used to determine the list of candidate AMF(s) from the AMF set. The NSSF may return the NSI ID(s) associated with the network slice instance(s) corresponding to the specific S-NSSAI. The NSSF may return the rejected S-NSSAI(s) as described in Section 5.15.4.1. The NSSF may return the configured NSSAI for the serving PLMN and the associated mapping of the configured NSSAI to the HPLMN S-NSSAI. The NSSF may return the target NSSAI as described in Section 5.3.4.3.3. Depending on the available information and based on the configuration, the AMF can query the appropriate NRF (e.g., locally pre-configured or provided by the NSSF) with the target AMF set. The NRF returns a list of candidate AMFs. If AMF reassignment is required, the current AMF reroutes the registration request or transfers the UE context to the target serving AMF as described in section 5.15.5.2.3. - Perform step (C).

[0243] (C) The serving AMF determines the registration area such that all S-NSSAIs of the authorized NSSAIs of this registration area are available in all tracking areas of the registration area (and taking into account other aspects as described in subclause 5.3.2.3), and then returns the authorized NSSAIs and, if provided, the mapping of the authorized NSSAIs to the subscribed S-NSSAIs to the UE. The AMF may return Rejected S-NSSAI(s) as described in subclause 5.15.4.1. NOTE 5: The S-NSSAI in the Authorized NSSAI for non-3GPP access is uniformly available in the PLMN in case of the N3IWF. For other types of non-3GPP access, the S-NSSAI in the Authorized NSSAI for non-3GPP access may not be uniformly available across the PLMN, e.g., different Wireline Access Gateway Functions (W-AGFs) may support different TAIs supporting different network slices.

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

[0245] If the Requested NSSAI does not contain an S-NSSAI that maps to an S-NSSAI of the HPLMN that is subject to network slice specific authentication and authorization, and the AMF determines that it cannot provide an S-NSSAI to the authorized NSSAI of the UE in the current UE tracking area and cannot add default S-NSSAI(s) as described in step (A), the AMF rejects the UE registration and includes a list of rejected S-NSSAIs in the reject message, each of which has an appropriate rejection cause value.

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

[0247] The AMF shall also provide a list of rejected S-NSSAIs, each with an appropriate rejection cause value. If a pending S-NSSAI is rejected by the NSSF, the AMF may abort 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 Section 5.3.4.3.1, or if a PCF is not deployed, the AMF shall determine the corresponding RFSP based on local configuration. The AMF then provides the target NSSAI and the corresponding RFSP to the NG-RAN as described in Section 5.3.4.3.3. If the S-NSSAI to be mapped to the S-NSSAI of the HPLMN subject to network slice-specific authentication and authorization is in progress, it shall be in "pending" state in the AMF and shall be included in the Pending NSSAI. The Pending NSSAI may include the mapping of the S-NSSAI(s) for the serving PLMN to the HPLMN S-NSSAI, if applicable. The UE shall not include any S-NSSAIs from the Pending NSSAIs it stores 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 If a Requested NSSAI was not provided or none of the S-NSSAIs in the Requested NSSAI matches any of the Subscribe S-NSSAIs, and all S-NSSAI(s) marked as default within the Subscribe S-NSSAI are subject to network slice-specific authentication and authorization, The AMF shall provide the UE with an "NSSAA to be performed" indicator in the registration accept message, but shall not provide an authorization NSSAI. Upon receiving the registration accept message, the UE is registered with the PLMN, but shall await the completion of network slice-specific authentication and authorization without attempting to use any of the services offered by the PLMN for any access, except, for example, emergency services (see TS 24.501

[47] ), until the UE receives the authorization NSSAI.

[0250] The AMF shall then initiate a network slice-specific authentication and authorization procedure for each S-NSSAI that requires it, as described in Section 5.15.10, except for S-NSSAIs for which network slice-specific authentication and authorization has already been initiated for another access type of the same S-NSSAI(s) based on network policy. At the end of the network slice-specific authentication and authorization step, the AMF shall provide the UE with a new authorized NSSAI via the UE Configuration Update procedure, which also includes the S-NSSAIs that were the subject of successful network slice-specific authentication and authorization. The AMF may perform AMF selection once the NSSAA for the S-NSSAIs that are the subject of the S-NSSAI in "pending" status is completed. If an AMF change is required, this shall be triggered by the AMF using the UE Configuration Update procedure, indicating that UE re-registration is required. S-NSSAIs that were not successfully authenticated and not authorized are not included in the authorized NSSAIs, but are included in the list of rejected S-NSSAIs with a reject cause value indicating a failure of network slice-specific authentication and authorization.

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

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

[0253] 5.15.5.2.2 Changing the set of network slice(s) for a UE The set of network slices for a 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 may 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, or operational reasons (e.g., a network slice instance is no longer available, or the load level information or service experience of a 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 an allowed NSSAI and a mapping of this allowed NSSAI to the HPLMN S-NSSAI for each access type to which the UE is registered. Additionally, the network may provide the configuration NSSAI for the serving PLMN, related mapping information, and the rejected S-NSSAI. The network may perform such a change via each access type during the registration procedure or may trigger notification of the network slice change to the UE using the UE Configuration Update procedure as specified in Section 4.2.4 of TS 23.502 [3]. The new Authorized NSSAI(s) and their mapping to the HPLMN S-NSSAI are determined as described in clause 5.15.5.2.1 (AMF reallocation may be required). The AMF shall inform the UE: - an indication that an acknowledgment from the UE is required; - the configured NSSAI (if required), rejected S-NSSAI(s) (if required), and TAI list for the serving PLMN; and -Provide a new authorized NSSAI (if applicable) with associated mappings of authorized NSSAIs for each access type, unless the AMF cannot determine a new authorized NSSAI (e.g., all S-NSSAIs within the old authorized NSSAI have been removed from the subscribed S-NSSAI).

[0255] moreover, -If changes to the allowed NSSAI affect the existing connection to the network slice (for example, a new S-NSSAI requires a separate AMF that cannot be determined by the current serving AMF, or the AMF cannot determine the allowed NSSAI), or if the changes do not affect the existing connection to the network slice, the UE needs to perform an immediate registration procedure due to AMF local policy; The serving AMF indicates to the UE the need to perform the registration procedure without including a 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 to allow it to enter CM-IDLE after receiving an acknowledgment from the UE. When the UE receives an indication to perform a registration procedure without including GUAMI or 5G-S-TMSI in the access stratum signaling after entering the CM-IDLE state, then: The UE deletes the stored (old) allowed NSSAI and associated mappings, as well as any (old) rejected S-NSSAI. The UE shall initiate the registration procedure with registration type Mobility Registration Update after the UE enters CM-IDLE state as described in step 4 of clause 4.2.4.2 of TS 23.502 [3]. The UE shall include the Requested NSSAI (as described in clause 5.15.5.2.1) in the Registration Request message along with the associated mapping of the Requested NSSAI. The UE shall also include the Requested NSSAI, but not the GUAMI, in access stratum signaling according to the conditions described in clause 5.15.9.

[0256] If there are established PDU session(s) associated with the emergency service, the serving AMF indicates to the UE the need for the UE 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 a new authorization NSSAI to the UE, the following applies when the network slice used for one or more PDU sessions becomes unavailable to the UE: If a 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 associated S-NSSAI should be released. The SMF releases the PDU session(s) according to clause 4.3.4.2 of TS 23.502 [3]. If a network slice is no longer available at the time of AMF change (e.g., due to a change in registration area), the new AMF indicates to the old AMF that the PDU session(s) corresponding to the associated S-NSSAI should be released. The old AMF notifies the corresponding SMF(s) to release the indicated PDU session(s). The SMF(s) release the PDU session(s) as described in clause 4.3.4 of TS 23.502 [3]. The new AMF then changes the PDU session status accordingly. The PDU session(s) context is released locally in the UE after receiving the PDU session status in the registration accept message.

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

[45] to determine whether ongoing traffic can be routed over existing PDU sessions belonging to other network slices or to establish new PDU session(s) associated with the same / other 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 S-NSSAI values ​​in the Requested NSSAI's mapping to the HPLMN's S-NSSAI included in the Registration Request matches the HPLMN's S-NSSAI associated with the PDU session, or - if none of the S-NSSAI values ​​in the Requested NSSAI match the value of the S-NSSAI of the HPLMN associated with the PDU session and no mapping of Requested NSSAIs to the S-NSSAI of the HPLMN is included in the Registration Request, The network shall release this PDU session as follows: The AMF notifies the corresponding SMF(s) to release the indicated PDU session(s). The SMF(s) release the PDU session(s) as described in clause 4.3.4 of TS 23.502 [3]. The AMF then changes the PDU session status accordingly. The PDU session(s) context is released locally in the UE after receiving the PDU session status from the AMF.

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

[0261] 5.15.5.2.3 AMF reassignment due to support of network slice(s) During the registration procedure in the PLMN, if the network determines that the UE should be served by a different AMF based on network slice(s), the AMF that first received the registration request redirects 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) are returned from the NSSF and identified by the list of candidate AMF(s), the redirect message should only be sent 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 a new AMF to serve the UE.

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

[0263] During handover from EPS to 5GS using the N26 interface procedure, if the network determines that the UE should be served by a different AMF based on aspects of the network slice(s), the AMF receiving 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 clause 4.11.1.2.2 of TS 23.502 [3].

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

[0265] 4.2.2.2.3 AMF Reassignment Registration When the AMF receives the registration request, the AMF may need to reroute the registration request to another AMF, for example, if the initial AMF is not an appropriate AMF to serve the UE. The registration by AMF re-allocation procedure described in Figure 15 (Figure 4.2.2.2.3-1) is used to reroute the UE's NAS messages to the target AMF during the registration procedure.

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

[0267] 1. If 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 a registration request message in an initial UE message to the initial AMF. If the UE is in the CM-CONNECTED state and triggers the registration procedure, the NG-RAN sends a registration request message in an uplink NAS transport message to the serving AMF, which is the initial AMF. The AMF can skip steps 2-3.

[0268] 2. If the AMF requires a Subscription Permanent Identifier (SUPI) and / or the UE's subscription information to decide whether to reroute the registration request, or if the registration request was not sent with integrity protection or if integrity protection is indicated as having failed, the AMF performs steps 4 to 9a or 9b of Figure 4.2.2.2.2-1.

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

[0270] 3b. Initial AMF to 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 section 5.2.3.3.1) service operation. The UDM can 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 may provide an indication of disaster roaming services to the UDM.

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

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

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

[0276] 4a. [Condition] Initial AMF to NSSF: Nnssf_NSSelection_Get(Requested NSSAI, [Requested NSSAI Mapping], Pending NSSAI, optionally [Pending NSSAI Mapping], subscribed S-NSSAI(s) with default S-NSSAI indication, [NSSRG Information], TAI, Allowed NSSAIs for other access types (if any), [Allowed NSSAI Mapping], Pending NSSAIs for other access types, optionally [Pending NSSAI Mapping], PLMN ID of SUPI).

[0277] If there is a need for slice selection (see section 5.15.5.2.1 of TS 23.501 [2]), for example, if the initial AMF cannot serve all S-NSSAI(s) from the Requested NSSAI(s) allowed by the subscription information, the initial AMF invokes 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 indication, the [NSSRG information], the allowed NSSAIs of other access types (if any), the mapping of the allowed NSSAI(s), the PLMN ID of the SUPI, and the TAI of the UE.

[0278] If available, the AMF includes the NSSRG information for the HPLMN's S-NSSAI as defined in clause 5.15.12 of TS 23.501 [2], including whether the UE indicated support for subscription-based restrictions on concurrent network slice registrations and whether the UDM indicated that it provides all subscribed S-NSSAIs for UEs that do not support it.

[0279] 4b. [Condition] NSSF for initial AMF: Response to Nnssf_NSSelection_Get(Set or list of AMF addresses, Allowed NSSAI for first access type, [Allowed NSSAI mapping], [Allowed NSSAI for second access type], [Allowed NSSAI mapping], [NSI ID(s)], [NRF(s)], [Rejection cause list (S-NSSAI(s), cause value(s))], [Configured NSSAI for serving PLMN], [Configured NSSAI mapping]).

[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 authorized NSSAI for the first access type, optionally the authorized NSSAI mapping, the pending NSSAI, optionally the [pending NSSAI mapping], the authorized NSSAI (if any) for the second access type, optionally the authorized NSSAI mapping, the pending NSSAI for the second access type, optionally the [pending NSSAI mapping], and a list of candidate AMF(s) based on the target AMF set or configuration. The NSSF may return the NSI ID(s) associated with the network slice instance(s) corresponding to the specific S-NSSAI(s). The NSSF may return the NRF(s) used to select the NF / service within the selected network slice instance(s). It may also return information about the rejection cause of the S-NSSAI(s) not included in the authorized NSSAI. The NSSF may return the configured NSSAI for the serving PLMN and possibly 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 may belong to any level of NRF according to the operator's deployment decision (see clause 6.2.6 of TS 23.501 [2]).

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

[0283] If the UE is in CM-IDLE and another AMF is selected, the initial AMF sends a rejection indication to the old AMF, indicating that the UE registration procedure was not fully completed by the initial AMF. The old AMF continues as if Namf_Communication_UEContextTransfer had never been received.

[0284] 6a. [Condition] Initial AMF to NRF: Nnrf_NFDiscovery_Request(NF Type, AMF Set).

[0285] If the initial AMF does not have the target AMF address stored locally and the initial AMF intends to use direct reroute to the target AMF or the reroute via (NG-R)AN message needs to include the AMF address, the initial AMF invokes the Nnrf_NFDiscovery_Request service operation from the NRF to discover a suitable target AMF with 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 NRF to AMF: Nnrf_NFDiscovery_Request ((AMF pointer, AMF address, and list of additional selection rules and NF capabilities)).

[0287] The NRF responds with a list of potential target AMF(s). The NRF may also provide details of the services offered by the candidate AMF(s), along with notification endpoints for each type of notification service that the selected AMF has registered with the NRF, if available. Alternatively, it may provide a list of potential target AMFs and their capabilities, as well as optionally additional selection rules. Based on information about the registered NFs and 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 forwards the NAS message to the target AMF by performing step 7(A).

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

[0290] NOTE 3: If AMF reallocation is performed by step 7(A), network slice separation cannot be fully 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 an NRF in the target AMF set (e.g., an NRF pre-configured locally on the AMF does not provide the requested information, or a query to an appropriate NRF provided by the NSSF is not successful, or the initial AMF has knowledge that the initial AMF is not authorized as a serving AMF), unless a security association has been established between the UE and the initial AMF, the initial AMF forwards a NAS message to the target AMF via the (R)AN performing step 7(B), containing the authorized NSSAI and AMF set, to allow the AN to select a target AMF as described in clause 6.3.5 of (R)TS 23.501 [2].

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

[15] . If the initial AMF obtained information from the NSSF as described in step 4b, that information, excluding the AMF set or list of AMF addresses, is included. Then, in step 8, the target AMF updates the (R)AN with the UE's new, updated N2 termination point in the first message from the target AMF to the RAN.

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

[0294] Editorial note: Whether UEs in CM-CONNECTED mode step 7(B) are also applicable 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 of Figure 4.2.2.2.2-1 (the target AMF corresponds to the new AMF), but this includes the UE context obtained from the old AMF. If a 5G security context is received from the initial AMF, the target AMF continues to use that security context instead of the 5G security context the target AMF may have obtained from the old AMF. If the initial AMF decides to forward a NAS message to the target AMF (step 7(A)), the first message from the target AMF to the (R)AN (either Initial Context Setup Request or Downlink NAS Transport) includes the AMF name of the initial AMF and the target AMF UE NGAP ID.

[0296] Modifications and Substitutions

[0033] Detailed embodiments have been described above. As will be appreciated by those skilled in the art, having the benefit of the disclosure embodied herein, several modifications and alternatives may be made to the above embodiments. By way of example, only some of these alternatives and modifications are described herein. In the above description, for ease of understanding, the UE 3 and network devices are described as having several separate modules (such as a communications control module). While these modules may be provided in this manner for a particular application, such as when an existing system is modified to implement the present disclosure, in other applications, such as systems designed from the beginning with the features of the present invention in mind, these modules may not be identifiable as separate entities because they may be incorporated into an overall operating system or code. These modules may be implemented in software, hardware, firmware, or a combination thereof.

[0297] Each controller may include any suitable form of processing circuitry including, for example (but not limited to), one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (IO) circuitry, 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 embodiments, a number of software modules have been described. As will be appreciated by those skilled in the art, the software modules may be provided in compiled or uncompiled form and may be supplied to the UE 3 and network devices via a computer network or as a signal on a recording medium. Furthermore, the functionality performed 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 because it facilitates updating the UE 3 and network devices to update their functionality.

[0299] In the above embodiments, 3GPP wireless communication (radio access) technologies are used. However, any other wireless communication technologies (e.g., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed line communication technologies (e.g., BBF access, cable access, optical access, etc.) may also be used in accordance with the above embodiments.

[0300] Items of user equipment may include, for example, communication devices such as mobile phones, smartphones, user equipment, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, etc. Such mobile (or generally fixed) devices are typically operated by a user, although so-called "Internet of Things (IoT)" devices and similar Machine-Type Communication (MTC) devices may also be connected to the network. For simplicity, this application will refer to mobile devices (or UEs) in the description, but it will be understood that the described techniques may be implemented on any communication device (mobile and / or generally fixed) that can connect to a communication network to send and receive data, regardless of whether such 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 will not be described in further detail here.

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

[0303] It will be understood that each block of the block diagrams may be implemented by computer program instructions. These computer program instructions may be provided to a general-purpose computer, a special-purpose computer, or a processor of other programmable data processing apparatus to produce a machine such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for performing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., multiple microprocessors, one or more microprocessors, or any other such configuration.

[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, a 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 previous description of the disclosed examples is provided to enable any 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. Thus, 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] While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, the present disclosure is not limited to these embodiments. Those skilled in the art will recognize that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined herein. For example, the above embodiments are not limited to 5GS, but may also be applied to communication systems other than 5GS (e.g., 6G systems, systems beyond 5G).

[0307] Additional notes All or part of the exemplary aspects disclosed above may be described as follows, but are not limited to: (Appendix 1) 1. A method of a first communication device, comprising: communicating with a second communication device; Sending, to a second communication device, Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) for a procedure related to reallocation of an Access and Mobility Management Function (AMF); Including, method. (Appendix 2) S-NSSAI is included in the Nnssf_NSSelection_Get message. The method described in Appendix 1. (Appendix 3) further including determining whether to include an S-NSSAI in the Nnssf_NSSelection_Get message; The method described in Appendix 2. (Appendix 4) S-NSSAI is included in Requested NSSAI, 4. The method according to any one of appendixes 1 to 3. (Appendix 5) determining an authorized NSSAI based on the S-NSSAI; Transmitting the authorization NSSAI; further comprising: 5. The method of any one of claims 1 to 4. (Appendix 6) transmitting a first S-NSSAI of the first Pending NSSAI for one access and a second S-NSSAI of the second Pending NSSAI for another access; 6. The method of any one of appendices 1 to 5. (Appendix 7) the first communication device is an AMF device; 7. The method of any one of appendices 1 to 6. (Appendix 8) The second communication device is a Network Slice Selection Function (NSSF) device. 8. The method of any one of appendices 1 to 7. (Appendix 9) Receiving Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI); and determining an Access and Mobility Management Function (AMF) set or list of AMF addresses based on the S-NSSAI; Sending an AMF set or a list of AMF addresses; Including, Method of communication device. (Appendix 10) S-NSSAI is included in the Nnssf_NSSelection_Get message. The method described in Appendix 9. (Appendix 11) S-NSSAI is included in Requested NSSAI, 11. The method of claim 9 or 10. (Appendix 12) determining an authorized NSSAI based on the S-NSSAI; Transmitting the authorization NSSAI; further comprising: 12. The method of any one of claims 9 to 11. (Appendix 13) 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; determining an AMF set or a list of AMF addresses based on the first S-NSSAI and the second S-NSSAI; further comprising: 13. The method of any one of appendices 9 to 12. (Appendix 14) The communication device is a Network Slice Selection Function (NSSF) device. 14. The method of any one of appendices 9 to 13. (Appendix 15) 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 a second communication device; Including, S-NSSAI is used for procedures related to the reassignment of Access and Mobility Management Function (AMF), A first communication device method. (Appendix 16) S-NSSAI is included in Requested NSSAI, The method described in Appendix 15. (Appendix 17) S-NSSAI is included in the Radio Resource Control (RRC) setup complete message. 17. The method of claim 15 or 16. (Appendix 18) 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 a CM-IDLE state; 19. The method of claim 17 or 18. (Appendix 20) The S-NSSAI is included in the UL information transfer message. 17. The method of claim 15 or 16. (Appendix 21) further comprising determining whether to include an S-NSSAI in the UL information transfer message; 21. The method described in Appendix 20. (Appendix 22) The first communication device is in a CM-CONNECTED state; 22. The method of claim 20 or 21. (Appendix 23) the first communication device is a user equipment; 23. The method of any one of appendices 15 to 22. (Appendix 24) the second communication device is a Radio Access Network (RAN) node; 24. The method of any one of appendices 15 to 23. (Appendix 25) Receiving Single Network Slice Selection Assistance Information (S-NSSAI) of Pending Network Slice Selection Assistance Information (NSSAI); and Sending an S-NSSAI; Including, S-NSSAI is used for procedures related to the reassignment of Access and Mobility Management Function (AMF), Method of communication device. (Appendix 26) S-NSSAI is included in the Radio Resource Control (RRC) setup complete message. The method described in Appendix 25. (Appendix 27) The S-NSSAI is included in the UL information transfer message. The method described in Appendix 25. (Appendix 28) The communication device is a Radio Access Network (RAN) node. 28. The method of any one of appendices 25 to 27. (Appendix 29) means for communicating with a second communication device; means for transmitting, to a second communication device, Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI) for a procedure related to Access and Mobility Management Function (AMF) reallocation; Including, A first communication device. (Appendix 30) S-NSSAI is included in the Nnssf_NSSelection_Get message. 30. The first communications device of claim 29. (Appendix 31) and further comprising means for determining whether to include an S-NSSAI in the Nnssf_NSSelection_Get message. 31. The first communication device of claim 30. (Appendix 32) S-NSSAI is included in Requested NSSAI, 32. The first communication device of any of Supplementary Notes 29 to 31. (Appendix 33) A means for determining an authorized NSSAI based on the S-NSSAI; a means for transmitting an authorization NSSAI; further comprising: 33. The first communication device of any of Supplementary Notes 29 to 32. (Appendix 34) and means for transmitting 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. 34. The first communication device of any of Supplementary Notes 29 to 33. (Appendix 35) the first communication device is an AMF device; 35. The first communication device of any of Supplementary Notes 29 to 34. (Appendix 36) The second communication device is a Network Slice Selection Function (NSSF) device. 36. The first communication device of any of Supplementary Notes 29 to 35. (Appendix 37) means for receiving 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 an AMF set or a list of AMF addresses; Including, Communication equipment. (Appendix 38) S-NSSAI is included in the Nnssf_NSSelection_Get message. 38. The communications device of claim 37. (Appendix 39) S-NSSAI is included in Requested NSSAI, 39. The communication device of claim 37 or 38. (Appendix 40) A means for determining an authorized NSSAI based on the S-NSSAI; a means for transmitting an authorization NSSAI; further comprising: 39. A communication device according to any one of Supplementary Notes 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 an AMF set or a list of AMF addresses based on the first S-NSSAI and the second S-NSSAI; further comprising: 41. A communication device according to any one of Supplementary Notes 37 to 40. (Appendix 42) The communication device is a Network Slice Selection Function (NSSF) device. 42. A communication device according to any one of Supplementary Note 37 to Supplementary Note 41. (Appendix 43) means for communicating with a second communication device; means for transmitting, to a second communication device, single network slice selection assistance information (S-NSSAI) included in pending network slice selection assistance information (NSSAI); Including, S-NSSAI is used for procedures related to the reassignment of Access and Mobility Management Function (AMF), A first communication device. (Appendix 44) S-NSSAI is included in Requested NSSAI, 44. The first communications device of claim 43. (Appendix 45) S-NSSAI is included in the Radio Resource Control (RRC) setup complete message. 45. The first communication device of claim 43 or 44. (Appendix 46) and means for determining whether to include an S-NSSAI in the RRC Setup Complete message. 46. ​​The first communications device of claim 45. (Appendix 47) The first communication device is in a CM-IDLE state; 47. The first communications device of claim 45 or 46. (Appendix 48) The S-NSSAI is included in the UL information transfer message. 45. The first communication device of claim 43 or 44. (Appendix 49) and means for determining whether to include an S-NSSAI in the UL information transfer message. 49. The first communications device of claim 48. (Appendix 50) The first communication device is in a CM-CONNECTED state; 50. The first communications device of claim 48 or 49. (Appendix 51) the first communication device is a user equipment; 51. The first communication device of any of Supplementary Notes 43 to 50. (Appendix 52) the second communication device is a Radio Access Network (RAN) node; 52. The first communication device of any of Supplementary Notes 43 to 51. (Appendix 53) means for receiving single network slice selection assistance information (S-NSSAI) of pending network slice selection assistance information (NSSAI); means for transmitting an S-NSSAI; Including, S-NSSAI is used for procedures related to the reassignment of Access and Mobility Management Function (AMF), Communication equipment. (Appendix 54) S-NSSAI is included in the Radio Resource Control (RRC) setup complete message. 54. The communication device of claim 53. (Appendix 55) The S-NSSAI is included in the UL information transfer message. 54. The communication device of claim 53. (Appendix 56) The communication device is a Radio Access Network (RAN) node. 56. A communication device according to any one of supplements 53 to 55. (Appendix 57) communicating with a second communication device; If the first communication device has a Pending Network Slice Selection Assistance Information (NSSAI), sending a Requested NSSAI to the second communication device; Including, Requested NSSAI includes Pending NSSAI, A first communication device method. (Appendix 58) The first communication device is an Access and Mobility Management Function (AMF); 58. The method described in Appendix 57. (Appendix 59) The second communication device is a Network Slice Selection Function (NSSF). 59. The method of claim 57 or 58. (Appendix 60) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. 59. The method of any one of appendices 57 to 59. (Appendix 61) The Requested NSSAI is a first Requested NSSAI, receiving a second Requested NSSAI from a User Equipment (UE); The first Requested NSSAI contains the second Requested NSSAI; 61. The method of any one of claims 57 to 60. (Appendix 62) The Requested NSSAI is a first Requested NSSAI, receiving a second Requested NSSAI from a User Equipment (UE); The first Requested NSSAI includes Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI; 61. The method of any one of claims 57 to 60. (Appendix 63) The second Requested NSSAI is included in the registration request message, 63. The method of claim 61 or 62. (Appendix 64) communicating with a second communication device; receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communication device if a Pending Network Slice Selection Assistance Information (NSSAI) is stored in the second communication device; Requested NSSAI includes Pending NSSAI, A first communication device method. (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); 66. The method of claim 64 or 65. (Appendix 67) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. 67. The method of any one of appendices 64 to 66. (Appendix 68) The Requested NSSAI is a first Requested NSSAI, the first Requested NSSAI includes the second Requested NSSAI; The second Requested NSSAI is transmitted from a user equipment (UE), 68. The method of any one of appendices 64 to 67. (Appendix 69) The Requested NSSAI is a first Requested NSSAI, The first Requested NSSAI includes Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI; The second Requested NSSAI is transmitted from a user equipment (UE), 68. The method of any one of appendices 64 to 67. (Appendix 70) The second Requested NSSAI is sent from the UE in a Registration Request message; 69. The method of claim 68 or 69. (Appendix 71) determining a list of Access and Mobility Management Function (AMF) sets or AMF addresses based on the Requested NSSAI; Sending an AMF set or a list of AMF addresses; further comprising: 71. The method of any one of claims 64 to 70. (Appendix 72) means for communicating with a second communication device; 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); Including, Requested NSSAI includes Pending NSSAI, A first communication device. (Appendix 73) The first communication device is an Access and Mobility Management Function (AMF); 73. The first communications device of claim 72. (Appendix 74) The second communication device is a Network Slice Selection Function (NSSF). 74. The first communications device of claim 72 or 73. (Appendix 75) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. 75. The first communications device of any of claims 72 to 74. (Appendix 76) The Requested NSSAI is a first Requested NSSAI, and means for receiving a second Requested NSSAI from a User Equipment (UE); The first Requested NSSAI contains the second Requested NSSAI; 76. The first communications device of any of Supplementary Notes 72 to 75. (Appendix 77) The Requested NSSAI is a first Requested NSSAI, and means for receiving a second Requested NSSAI from a User Equipment (UE); The first Requested NSSAI includes Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI; 76. The first communications device of any of Supplementary Notes 72 to 75. (Appendix 78) The second Requested NSSAI is included in the registration request message, 78. The first communications device of claim 76 or 77. (Appendix 79) means for communicating with a second communication device; means for receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communication device when a Pending Network Slice Selection Assistance Information (NSSAI) is stored in the second communication device; Includes Requested NSSAI includes Pending NSSAI, A first communication device. (Appendix 80) The first communication device is a Network Slice Selection Function (NSSF). 80. The first communications device of claim 79. (Appendix 81) The second communication device is an Access and Mobility Management Function (AMF); 81. The first communications device of claim 79 or 80. (Appendix 82) The Requested NSSAI is included in the Nnssf_NSSelection_Get message. 82. The first communication device of any of Supplementary Notes 79 to 81. (Appendix 83) The Requested NSSAI is a first Requested NSSAI, the first Requested NSSAI includes the second Requested NSSAI; The second Requested NSSAI is transmitted from a user equipment (UE), 83. The first communications device of any of Supplementary Notes 79 to 82. (Appendix 84) The Requested NSSAI is a first Requested NSSAI, The first Requested NSSAI includes Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI; The second Requested NSSAI is transmitted from a user equipment (UE), 83. The first communications device of any of Supplementary Notes 79 to 82. (Appendix 85) The second Requested NSSAI is sent from the UE in a Registration Request message; 85. The first communications device of claim 83 or 84. (Appendix 86) means for determining a list of Access and Mobility Management Function (AMF) sets or AMF addresses based on the Requested NSSAI; means for transmitting an AMF set or a list of AMF addresses; further comprising: 86. The first communications device of any of Supplementary Notes 79 to 85.

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

[0309] 3 User Device 20 Data Network 201AF 31 Transceiver Circuit 32 Antenna 33 Control Unit 34 User Interface 35 USIM 36 memory 361 Operating Systems 362 Communication Control Module 3621 Transceiver Control Module 5 (R)AN nodes 51 Transceiver circuit 52 Antenna 53 Network Interface 54 Control Unit 55 memory 551 Operating Systems 552 Communication Control Module 5521 Transceiver Control Module 60RU 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 interfaces 743 Control Unit 744 memory 7441 Operating System 7442 Communication Control Module 74421 Transceiver Control Module 75 UDM 751 Transceiver Circuit 752 network interfaces 753 Control Unit 754 memory 7541 Operating Systems 7542 Communication Control Module 75421 Transceiver Control Module 76 NSSF 761 Transceiver Circuit 762 network interfaces 763 Control Unit 764 memory 7641 Operating System 7642 Communication Control Module 76421 Transceiver Control Module

Claims

1. 1. A method of a first communication device, comprising: If the first communication device holds a Pending Network Slice Selection Assistance Information (NSSAI), sending a Requested NSSAI to a second communication device. Including, the Requested NSSAI includes the Pending NSSAI, The second communication device is a Network Slice Selection Function (NSSF). method.

2. 1. A method of a first communication device, comprising: receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communication device when a Pending Network Slice Selection Assistance Information (NSSAI) is held in the second communication device; Including, the Requested NSSAI includes the Pending NSSAI, The first communication device is a Network Slice Selection Function (NSSF). method.

3. a first communication device, means for transmitting a Requested Network Slice Selection Assistance Information (NSSAI) to a second communication device when the first communication device holds a Pending Network Slice Selection Assistance Information (NSSAI); Including, the Requested NSSAI includes the Pending NSSAI, The second communication device is a Network Slice Selection Function (NSSF). A first communication device.

4. the first communication device is an Access and Mobility Management Function (AMF); The first communication device according to claim 3 .

5. The Requested NSSAI is included in the Nnssf_NSSelection_Get message.

5. The first communication device according to claim 3 or 4.

6. the Requested NSSAI is a first Requested NSSAI, means for receiving a second Requested NSSAI from a User Equipment (UE); the first Requested NSSAI includes the second Requested NSSAI; 5. The first communication device according to claim 3 or 4.

7. the Requested NSSAI is a first Requested NSSAI, means for receiving a second Requested NSSAI from a User Equipment (UE); The first Requested NSSAI includes Single Network Slice Selection Assistance Information (S-NSSAI) of the second Requested NSSAI; 5. The first communication device according to claim 3 or 4.

8. the second Requested NSSAI is included in a registration request message; The first communication device according to claim 6 .

9. a first communication device, means for receiving a Requested Network Slice Selection Assistance Information (NSSAI) from the second communication device when a Pending Network Slice Selection Assistance Information (NSSAI) is held in the second communication device; Including, the Requested NSSAI includes the Pending NSSAI, The first communication device is a Network Slice Selection Function (NSSF). A first communication device.

10. the second communication device is an Access and Mobility Management Function (AMF); The first communication device according to claim 9 .

11. The Requested NSSAI is included in the Nnssf_NSSelection_Get message. The first communication device according to claim 9 .

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 first communication device according to claim 9 .

13. the Requested NSSAI is a first Requested NSSAI, The first Requested NSSAI includes 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 claim 9 .

14. The second Requested NSSAI is sent from the UE by a registration request message. The first communication device of claim 12.

15. means for determining an Access and Mobility Management Function (AMF) set or a list of candidate AMFs based on the Requested NSSAI; means for transmitting the AMF set or the list of candidate AMFs; further comprising: The first communication device according to claim 9 .

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