AMF method, UE method, AMF and UE

Abstract

The present disclosure proposes solutions to some situations in a 3GPP node or in connections between 3GPP nodes during a Network Slice Admission Control (NSAC) procedure. An Access and Mobility Management Function (AMF) device in communication with a User Equipment (UE) and a Network Slice Admission Control Function (NSACF) device includes a receiver and a transmitter. The receiver is configured to receive a registration request message from the UE, the registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI). The transmitter is configured to transmit a Non-Access Stratum (NAS) message to the UE, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first capability. The transmitter is configured to transmit the NAS message to the UE, the NAS message including a rejection NSSAI including a second cause value, if the UE does not support the first capability.

Description

[Technical field]

[0001] The present disclosure relates to an Access and Mobility Management Function (AMF) device, a User equipment (UE), an AMF device method, and a UE method. [Background technology]

[0002] Network slicing features were defined in the 3GPP Release 15 and Release 16 standard specifications. GSMA 5GJA introduced the concept of Generic network slice template (GST) in 3GPP 5GJA IEEE 802.11b, from which several network slice type descriptions can be derived. Some of the parameters in GST explicitly indicate the definition of parameters and scope in the service provided to the end customer. For example, GST aims to limit the number of PDU sessions / PDN connections per network slice or the number of devices supported per network slice, or the maximum UL or DL ​​data rate per network slice. 3GPP 5GJA IEEE 802.11b, IEEE 802.11b, and IEEE 802.11c have identified and addressed the gaps that need to be filled in providing support for the implementation of GST parameters, and suitable solutions to address the gaps. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications". V17.0.0 (2020-07) [Non-Patent Document 2] 3GPP TS 23.501: "System architecture for the 5G System (5GS)". V17.1.1 (2021-06) [Non-licensed document 3] 3GPP TS 23.502: "Procedures for the 5G System (5GS)". V17.1.0 (2021-06)

Non-licensed Document 4

Non-licensed Document 5

Non-licensed Document 6

Non-licensed Document 7

Non-licensed Document 8

Non-licensed literature 9

Non-licensed literature 10

[0004] A Network Slice Admission Control (NSAC) procedure is defined in 5GS to manage the number of UEs registered in a network slice and to manage the number of PDU sessions established in the network slice. This procedure also defines a procedure to manage a scenario where the network receives a request from a UE to register in the network slice and the number of UEs registered in the network slice meets or exceeds the total quota of UEs that can be registered in the network slice at a given time. A similar procedure is also defined for a scenario where the network receives a request from a UE to establish a PDU session in the network slice and the total number of PDU sessions established in the network slice meets or exceeds the total quota of PDU sessions that can be established in the network slice at a given time.

[0005] However, significant problems still exist regarding some situations in 3GPP nodes or in connections between 3GPP nodes during NSAC procedures.

[0006] For example, the 3GPP standard for NSAC procedures has some unclear descriptions for some situations. For example, if the Network Slice Admission Control Function (NSACF) does not respond to a request from the AMF, it is unclear how the AMF should handle the UE during the registration procedure.

[0007] For example, if the Network Slice Admission Control Function (NSACF) does not respond to a request from the SMF, it is unclear how the SMF should handle the PDU session during the PDU session establishment procedure. [Means for solving the problem]

[0008] In an aspect of the disclosure, an Access and Mobility Management Function (AMF) device in communication with a User Equipment (UE) and a Network Slice Admission Control Function (NSACF) device includes a receiver and a transmitter. The receiver is configured to receive a registration request message from the UE, the registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI). The transmitter is configured to transmit a Non-Access Stratum (NAS) message to the UE, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first capability. The transmitter is configured to transmit the NAS message to the UE, the NAS message including a rejection NSSAI including a second cause value, if the UE does not support the first capability.

[0009] In an aspect of the disclosure, a User Equipment (UE) communicating with an Access and Mobility Management Function (AMF) device communicating with a Network Slice Admission Control Function (NSACF) device includes a receiver and a transmitter. The transmitter is configured to transmit a registration request message to the AMF device, the registration request message including first information indicating whether the UE supports a first function and a requested Network Slice Selection Assistance Information (NSSAI). The receiver is configured to receive a Non-Access Stratum (NAS) message from the AMF device, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first function. The receiver is configured to receive the NAS message from the AMF device, the NAS message including a rejection NSSAI including a second cause value, if the UE does not support the first function.

[0010] In an aspect of the disclosure, a method of an Access and Mobility Management Function (AMF) device communicating with a User Equipment (UE) and a Network Slice Admission Control Function (NSACF) device includes receiving a Registration Request message from the UE, the Registration Request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI). The method includes transmitting a Non-Access Stratum (NAS) message to the UE, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first capability. The method includes transmitting the NAS message to the UE, the rejection NSSAI including a second cause value, if the UE does not support the first capability.

[0011] In an aspect of the disclosure, a method of a User Equipment (UE) communicating with an Access and Mobility Management Function (AMF) device communicating with a Network Slice Admission Control Function (NSACF) device includes sending a Registration Request message to the AMF device, the Registration Request message including first information indicating whether the UE supports a first function and a requested Network Slice Selection Assistance Information (NSSAI). The method includes receiving a Non-Access Stratum (NAS) message from the AMF device including a reject NSSAI including a first cause value and a back-off timer value if the UE supports the first function. The method includes receiving the NAS message from the AMF device including a reject NSSAI including a second cause value if the UE does not support the first function. [Brief description of the drawings]

[0012] [Figure 1] Figure 1 shows an example of a successful network slice admission control procedure. [Diagram 2] FIG. 2 shows the registration procedure for the S-NSSAI when the NSACF does not respond. [Diagram 3] FIG. 3 shows a UE registration procedure for S-NSSAI according to NSAC. [Figure 4] FIG. 4 shows the registration procedure for S-NSSAI according to NSAC. [Diagram 5] Figure 5 shows a PDU session establishment procedure with network slice admission control. [Figure 6] FIG. 6 shows an overview of the system. [Figure 7]FIG. 7 is a block diagram of a user equipment (UE). [Figure 8] FIG. 8 is a block diagram of an (R)AN node. [Figure 9] Figure 9 shows a system overview of an (R)AN node based on the O-RAN architecture. [Figure 10] FIG. 10 is a block diagram of a Radio Unit (RU). [Figure 11] FIG. 11 is a block diagram of a distributed unit (DU). [Figure 12] FIG. 12 is a block diagram of a Centralized Unit (CU). [Figure 13] FIG. 13 is a block diagram of AMF. [Figure 14] FIG. 14 is a block diagram of the SMF. [Figure 15] FIG. 15 is a block diagram of the UPF. [Figure 16] FIG. 16 is a block diagram of the PCF. [Figure 17] FIG. 17 is a block diagram of the NEF. [Figure 18] FIG. 18 is a block diagram of the UDM. [Figure 19] FIG. 19 is a block diagram of NWDAF. [Figure 20] FIG. 20 is a block diagram of the NSACF. [Figure 21] Figure 21 shows a procedure for checking and updating the availability of the number of UEs per network slice. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <abbreviation> For purposes of this specification, the abbreviations given in Non-Patent Document 1 and the following apply: An abbreviation defined in this specification takes precedence over the definition of the same abbreviation in Non-Patent Document 1 if such abbreviation exists.

[0014] 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 ABBA Anti-Bidding-down Between Architectures AF Application Function AMF Access and Mobility Management Function API Application Programming Interface AS Access Stratum ATSSS Access Traffic Steering, Switching, Splitting ATSSS-LL ATSSS Low-Layer AUSF Authentication Server Function AUTN Authentication token BBF Broadband Forum 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 CU Centralized Unit 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 DU Distributed Unit ePDG evolved Packet Data Gateway EAP Extensible Authentication Protocol 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 HR Home Routed (roaming) IAB Integrated access and backhaul IMEI International Mobile Equipment Identity IMEI / TAC IMEI Type Allocation Code IMS IP Multimedia Subsystem IOWN Innovative Optical and Wireless Network 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 LTE Long Term Evolution MAC Medium Access Control MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MNC Mobile Network Code MO Mobile Originated MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol MT Mobile Terminated MT Mobile Termination N3IWF Non-3GPP InterWorking Function 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 ngKSI Next Generation Key Set Identifier 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 NW-TT Network-side TSN translator NWDAF Network Data Analytics Function O-RAN Open RAN Alliance O-DU O-RAN Distributed Unit O-CU O-RAN Centralized Unit O-RU O-RAN Radio Unit PCF Policy Control Function PDB Packet Delay Budget PDCP Packet Data Convergence Protocol 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 QoS Quality of Service RACS Radio Capabilities Signalling optimisation (R)AN (Radio) Access Network RG Residential Gateway RU Radio Unit RIM Remote Interference Management RLC Radio Link Control RQA Reflective QoS Attribute RQI Reflective QoS Indication RRC Radio Resource Control RSN Redundancy Sequence Number SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SDAP Service Data Adaptation Protocol SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SMF Session Management Function SMS Short Message Service 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 SOR Steering Of Roaming 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 TAI Tracking Area Identity TCP Transmission Control Protocol 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 UP User Plane UPF User Plane Function URLLC Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy UU Interface between User Equipment and Radio Access Network VID VLAN Identifier VLAN Virtual Local Area 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 WLAN Wireless Local Area Network WUS Wake Up Signal

[0015] <Definition> For purposes of this specification, the terms and definitions given in Non-Patent Document 1 and the following apply. Terms defined in this specification take precedence over the definition of the same term in Non-Patent Document 1 if such term appears therein.

[0016] <General remarks> Those skilled in the art will appreciate that elements in the figures may be shown in simplified form and not necessarily drawn to scale. Further, with respect to the structure of a device, one or more components of the device may be represented by conventional symbols in the figures, and the figures may show only certain details appropriate to understanding 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.

[0017] To promote an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the principles. It will nevertheless be understood that no limitation of the scope of the present disclosure is intended thereby. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the present disclosure that would normally occur to one skilled in the art, are to be construed as being within the scope of the present disclosure.

[0018] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method comprising a list of steps may include not only those steps, but also other steps not expressly listed or inherent in such process or method. Similarly, the term "comprising" preceding one or more devices, entities, subsystems, elements, structures, or components does not, absent further constraints, preclude the presence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures, or additional components. Throughout this specification, the phrases "in an embodiment," "in another embodiment," and similar terms may all refer to the same embodiment, but do not necessarily do so.

[0019] 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.

[0020] In the following specification and claims, reference will be made to a number of terms that are defined to have the following meanings: The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0021] Information as used herein refers to data and knowledge, since data is meaningful information and represents values ​​attributed to parameters. Moreover, knowledge refers to an understanding of an abstract or concrete concept. It should be noted that the exemplary system is simplified to facilitate the description of the subject matter of the present disclosure and is not intended to limit the scope of the present disclosure. Other devices, systems, and configurations may be used in addition to or instead of the system to implement aspects disclosed herein, and all such aspects are contemplated to be within the scope of the present disclosure.

[0022] Each of the aspects and elements included in each aspect described below may be implemented independently or in combination with each other, and each aspect includes different novel features, and thus contributes to achieving different objectives or solving different problems and achieving different advantages.

[0023] This disclosure proposes solutions to some situations in 3GPP nodes or in connections between 3GPP nodes during NSAC procedures.

[0024] Figure 1 shows an example of a successful network slice admission control procedure when the AMF registers the UE with the NSACF.

[0025] 1. The AMF triggers an NSAC procedure to register the UE to the NSACF. For example, when the AMF receives a Registration Request message from the UE, the AMF performs the NSAC procedure. The AMF triggers an availability check and update procedure for the number of UEs per network slice to update (i.e., increase) the number of UEs registered in the network slice if the S-NSSAI complies with NSAC.

[0026] 2. The AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF. The AMF may include a UE ID, an access type, an S-NSSAI to which the UE is registered, and an update flag in the message. The UE ID may be a UE identity or a UE identifier. The access type may be 3GPP access or Non-3GPP access. The update flag may be as described in Non-Patent Document 3.

[0027] 3. Upon receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message, the NSACF registers the UE to the S-NSSAI and counts or increments the number of UEs registered to the S-NSSAI for allocation control based on the information provided by the AMF.

[0028] 4. The NSACF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message to the AMF indicating success of NSAC for the UE.

[0029] In one example, the UDM in the supporting HPLMN may optionally maintain a record of PEI or type assigned code value for UE capability supporting NSAC function. The UDM may indicate to the AMF that the UE supports the NSAC function based on the configuration or optional PEI record. The UDM may indicate to the AMF whether the UE supports the NSAC function based on the PEI in both the HPLMN and VPLMN cases.

[0030] <First aspect> The first aspect discloses a registration procedure for an S-NSSAI in case the NSACF does not respond.

[0031] If the AMF sends a message to the NSACF to register the UE for the S-NSSAI and does not receive a response from the NSACF during the registration procedure, the AMF considers that registration of the S-NSSAI is not available for a certain period of time and indicates this to the UE.

[0032] This aspect discloses the behavior of the AMF when the AMF does not receive any response to registering the S-NSSAI to the NSACF for the UE. There may be scenarios when the NSACF receives too many messages from the AMF updating the UE registration to the S-NSSAI or when the interface between the AMF and the NSACF does not function. In such scenarios, the AMF may not receive a response from the NSACF for a certain period of time or may not receive a response at all. The AMF may not receive a response from the NSACF for the registration procedure to proceed. NSACF Waiting for a response message from

[0033] This aspect discloses that the AMF rejects registration of the S-NSSAI if the AMF does not receive a response message from the NSACF within a predetermined period. In this case, the AMF sends a NAS message (e.g., a Registration Reject message or a Registration Accept message or a Configuration Update Command message) including the S-NSSAI in a Rejected NSSAI with a cause value indicating a temporary failure. The NAS message may include a value of a back-off timer. The value of the back-off timer may be referred to as a back-off timer value. When the UE receives the NAS message, the UE starts a timer T. The UE does not initiate another registration procedure to register to the S-NSSAI while timer T is running.

[0034] Figure 2 shows the AMF processing of the S-NSSAI registration procedure when the AMF does not receive a response from the NSACF.

[0035] The detailed process of the embodiment is described as follows.

[0036] 1. To perform an Early Admission Control (EAC) procedure, the NSACF may send an Nnsacf_NumberOfUEsPerSliceEACNotify message with an S-NSSAI to the AMF. The Nnsacf_NumberOfUEsPerSliceEACNotify message includes an EAC flag set to "active". The EAC flag may indicate whether the EAC mode is activated or deactivated. The EAC flag set to "active" may indicate that the EAC mode is activated.

[0037] 2. The UE initiates the registration procedure to register the UE for the S-NSSAI by sending a Registration Request message including the S-NSSAI in the Requested NSSAI to the AMF. The UE starts a timer T3510. The UE includes an indicator in the Registration Request message indicating whether the UE supports the NSAC procedure. The indicator may indicate whether the UE supports the NSAC capability or NSAC. The indicator is included in the 5GMM capabilities or as another specified parameter in the Registration Request message. The indicator may be referred to as an NSAC support indicator or NSACF supported capability information.

[0038] 3. When the AMF receives a registration request message from the UE, the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF requesting the NSACF to register the UE for the S-NSSAI. The AMF stores the 5GMM capabilities and the NSACF supported capabilities information. The AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message for both UEs that support the NSAC capability and UEs that do not support the NSAC capability if the S-NSSAI follows NSAC. If the NSACF supported capabilities information is not included in the registration request message or the NSACF supported capabilities information from the UE indicates that the UE does not support the NSAC procedure, the AMF determines that the UE does not support the NSAC procedure or the NSAC capability. If the NSACF supported capabilities information is included in the registration request message, the AMF determines that the UE supports the NSAC procedure or the NSAC capability.

[0039] The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message may include an S-NSSAI.

[0040] 4. When the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF, the AMF starts timer Tamf, and the AMF waits for a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF.

[0041] 5-6. If the timer Tamf expires in the AMF and the AMF has not received a response (e.g., a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message) from the NSACF, the AMF sends a NAS message to the UE including the S-NSSAI in the Rejected NSSAI, a cause value indicating that the S-NSSAI is temporarily unavailable. The NAS message may include a value of the back-off timer for the S-NSSAI. The NAS message may be one of the following messages:

[0042] If the Request NSSAI in step 2 includes only the S-NSSAI for which the AMF did not receive a response from the NSACF, the NAS message may be a Registration Reject message. In this case, the network (e.g., the AMF) maintains the UE context in the AMF. The UE context in the AMF indicates that a response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message is pending for the S-NSSAI and that the S-NSSAI is rejected for the UE's registration.

[0043] If the request NSSAI in step 2 also includes a second S-NSSAI other than the S-NSSAI for which the AMF did not receive a response from the NSACF, and the second S-NSSAI is successfully registered in 5GS, the NAS message may be a registration accept message. The S-NSSAI for which the AMF did not receive a response from the NSACF may be referred to as the first S-NSSAI. The AMF indicates by using the registration accept message that a response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message is pending for the first S-NSSAI and that the first S-NSSAI is rejected for the UE.

[0044] 7. Upon receiving the NAS message, the UE starts a timer T with a value set to the backoff time value for the S-NSSAI received in the NAS message. The UE does not initiate registration for the S-NSSAI to the network until timer T expires. For example, if a backoff time value for the S-NSSAI is included in the NAS message, the UE starts a timer T with a value set to the backoff time value, and the UE does not initiate registration for the S-NSSAI to the network until timer T expires. The backoff time value may be referred to as a value of a timer for stopping the registration procedure for the S-NSSAI. For example, the UE holds off the registration procedure for the S-NSSAI until timer T expires.

[0045] 8-9. After the NAS message in step 6 is sent to the UE, when the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF, the AMF may perform one of the following operations:

[0046] -If the AMF determines that the S-NSSAI is rejected (e.g., if the AMF receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE's registration for the S-NSSAI has failed), the AMF sends a message (e.g., an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message) to the NSACF with an update flag set to "reduce" to reduce the number of UEs for the S-NSSAI, i.e., to deregister the UE for the S-NSSAI in the NSACF.

[0047] If the AMF determines that the UE is registered in the network (e.g., the AMF receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE is successfully registered to the NSACF, or the AMF sends a registration acknowledgement message in step 6), the AMF initiates an existing mobile terminated NAS procedure (e.g., a service request procedure) and sends a NAS message (e.g., a configuration update command message) including the S-NSSAI in an Allowed NSSAI information element to the UE. The Allowed NSSAI information element may be referred to as an Allowed NSSAI.

[0048] If the UE receives a NAS message, the UE stops timer T, stores the received S-NSSAI in the Allowed NSSAI at the UE, and removes the received S-NSSAI from the Rejected NSSAI at the UE.

[0049] <First variant of the first embodiment> In one example, if the NSACF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message including a UE ID and there is no UE context corresponding to the UE ID in the AMF, the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message including the UE ID, the S-NSSAI, and an update flag set to "reduce" to reduce the number of UEs for the S-NSSAI, i.e., to deregister the UE for the S-NSSAI in the NSACF.

[0050] <Second variant of the first embodiment> In one example, even if the timer started in step 4 expires, the AMF does not send a registration accept message or a registration reject message until the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF. If the timer T3510 expires in the UE, the UE aborts the ongoing registration procedure.

[0051] <Third variant of the first embodiment> In one example, when the timer Tamf expires, the AMF resends the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message of step 3 to the NSACF.

[0052] In the AMF, if the number of message retransmissions exceeds the default number, the AMF stops retransmitting the message to the NSACF and continues from step 5.

[0053] <Fourth variant of the first aspect> In one example, in step 5, the AMF approves the UE registration for the S-NSSAI and sends the S-NSSAI in the allowed NSSAI in the registration accept message. For example, if there is no response from the NSACF until the timer Tamf expires, the AMF may send the S-NSSAI in the allowed NSSAI in the registration accept message.

[0054] In step 8, when the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE registration for the S-NSSAI is unsuccessful, the AMF removes the S-NSSAI from the allowed NSSAI list. The allowed NSSAI list may be referred to as a list of allowed NSSAIs or allowed NSSAIs. The allowed NSSAI list may be stored in the AMF. Then, if the AMF determines that the UE has at least one allowed S-NSSAI (e.g., if the AMF determines that the UE has at least an allowed NSSAI sent in the registration accept message), the AMF initiates a general UE configuration update procedure by sending a configuration update command message including the new allowed NSSAI, a rejected NSSAI including the S-NSSAI, a cause value indicating that the S-NSSAI is not available due to reaching the maximum number of UEs, and an optional back-off timer (e.g., a back-off timer value). For example, if the AMF determines that the UE has at least one authorized NSSAI based on the UE context for the UE in the AMF, the AMF initiates a general UE configuration update procedure by sending a configuration update command message. For example, the new authorized NSSAI does not include the S-NSSAI.

[0055] If the AMF determines that the UE has no authorized NSSAIs (e.g., the AMF determines that the UE has no authorized NSSAIs based on the UE context for the UE in the AMF), the AMF sends a deregistration request message including a cause value indicating that the S-NSSAI is not available due to the maximum number of S-NSSAIs, UEs in the rejected NSSAI being reached. The deregistration request message may include a back-off timer value.

[0056] If the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicates that the UE's registration for the S-NSSAI is successful, the AMF maintains the allowed NSSAI list for the UE as is.

[0057] <Fifth variant of the first aspect> If the AMF determines that the UE does not support the NSAC function, in step 6, the AMF sends a NAS message including the S-NSSAI in the allowed NSSAI list. For example, if the AMF determines that the UE does not support the NSAC function and the AMF does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF until Tamf is terminated, in step 6, the AMF sends a NAS message including the S-NSSAI in the allowed NSSAI list. For example, if the AMF determines that the UE does not support the NSAC function regardless of receiving a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF and Tamf, in step 6, the AMF sends a NAS message including the S-NSSAI in the allowed NSSAI list.

[0058] In step 8, if the AMF determines that the UE is not successfully registered (e.g., if the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE registration for the S-NSSAI is not successful), the AMF determines that the UE does not support the NSAC function, and the AMF determines that the UE has at least one allowed NSSAI (e.g., based on the UE context for the UE in the AMF, the AMF determines that the UE has at least one allowed NSSAI), the AMF initiates a general UE configuration update procedure by sending a configuration update command message. The configuration update command message includes a rejected NSSAI that includes the new allowed NSSAI and the S-NSSAI, together with a cause value indicating that the S-NSSAI is not allowed in the tracking area. For example, the new allowed NSSAI does not include the S-NSSAI.

[0059] If the AMF determines that the UE does not have any allowed NSSAIs (e.g., the AMF determines that the UE does not have any allowed NSSAIs based on the UE context in the AMF), the AMF sends a deregistration request message, which includes the S-NSSAI in the rejected NSSAI with a cause value indicating that the S-NSSAI is not allowed in the tracking area. The AMF may determine whether the UE has at least one allowed NSSAI based on the UE context in the AMF.

[0060] The AMF periodically sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to register the UE to the S-NSSAI in the NSACF.

[0061] Upon receiving a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating a successful operation (e.g., upon receiving a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating successful registration of the UE for the S-NSSAI), the AMF initiates a Configuration Update Command procedure by sending a Configuration Update Command message including the S-NSSAI in the Allowed NSSAI list. When the UE receives the Configuration Update Command message, the UE stores the Allowed NSSAIs and removes the S-NSSAI from the Rejected NSSAIs.

[0062] In one example, if the AMF determines that the operation is not successful (e.g., if the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE's registration for the S-NSSAI is not successful) and the AMF determines that the UE does not support the NSAC function, the AMF maintains the S-NSSAI in the allowed NSSAI list, but the AMF rejects UL NAS transport messages, including 5GSM messages (e.g., the AMF rejects the establishment of a PDU session for the S-NSSAI). The AMF periodically sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to register the UE for the S-NSSAI in the NSACF. Upon receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating a successful operation (e.g., when the AMF receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE's registration to the S-NSSAI is successful), the AMF starts processing the 5GSM message received in the UL NAS transport message and sends the 5GSM message to the SMF for processing.

[0063] <Sixth variant of the first aspect> If the NSACF indicates "EAC is deactivated" in step 1 and the AMF receives a registration request message in step 2, the AMF first completes the registration procedure by returning a registration approval message or a registration rejection message to the UE in step 6 based on the result of the normal registration procedure according to non-patent document 3. If the AMF returns the S-NSSAI in the allowed NSSAI to the UE and the S-NSSAI complies with the NSAC, after the completion of the registration procedure, the AMF triggers a request to the NSACF for NSAC regarding the number of UEs registered to the S-NSSAI. For example, the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message. For example, the AMF starts Tamf when it sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message and sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message. And it is as follows.

[0064] -If the AMF receives a response from the NSACF with information indicating that the maximum number of UEs registered to the S-NSSAI has been reached or exceeded (e.g., when the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE's registration to the S-NSSAI is not successful), the AMF triggers a UE configuration update procedure, and the AMF returns the S-NSSAI in a rejected NSSAI to change the state of the S-NSSAI in the UE from "Allowed" to "Rejected". For example, the AMF sends the S-NSSAI in a rejected NSSAI to the UE during the UE configuration update procedure. The AMF may return a reject cause to the UE indicating that the maximum number of registered UEs has been reached, and the AMF may also return a back-off timer value to the UE.

[0065] -If the AMF does not receive any response from the NSACF, the AMF returns an S-NSSAI in a Rejected NSSAI to the UE to change the state of the S-NSSAI in the UE from "Allowed" to "Rejected". The AMF may return a rejection cause to the UE indicating that the maximum number of registered UEs has been reached, and the AMF may also return a back-off timer value to the UE.

[0066] -If a timer (e.g., Tamf) in the AMF is running and the AMF does not receive a response from the NSACF before the timer expires, the AMF may repeat the request to the NSAC for the S-NSSAI several times (e.g., the number of repetitions is defined in the AMF). For example, the AMF may repeat sending an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message for the S-NSSAI to the NSACF.

[0067] If the UE enters idle mode (e.g., the N1 signaling connection is released) while the AMF is checking NSAC for the S-NSSAI, the AMF may first page the UE, and when the UE is connected again, the AMF updates the state of the S-NSSAI in the UE via a UE configuration update procedure.

[0068] For example, embodiment 1 and the variants of embodiment 1 propose solutions to some situations in a 3GPP node or in connections between 3GPP nodes during an NSAC procedure.

[0069] For example, aspect 1 and the variants of aspect 1 can solve prominent problems with respect to some situations in 3GPP nodes or connections between 3GPP nodes during NSAC procedures.

[0070] For example, embodiment 1 and the variants of embodiment 1 propose solutions to some situations where the 3GPP standard for NSAC procedures has some unclear descriptions for some situations.

[0071] For example, aspect 1 and a variant of aspect 1 can solve the problem that it is unclear how the AMF should handle the UE during the registration procedure if the Network Slice Admission Control Function (NSACF) does not respond to a request from the AMF.

[0072] <Second aspect> The second aspect discloses that the AMF changes the registration status of the S-NSSAI in the UE when the EAC flag is set to "inactive".

[0073] This aspect discloses the behavior of the AMF when the AMF receives a request from the NSACF to deactivate the EAC procedure for the S-NSSAI. After the AMF sends a request to the NSACF to register the UE for the S-NSSAI at the NSACF during the registration procedure, NSACF If no response message is received from the UE, the aspect discloses that the AMF updates the registration status of the S-NSSAI for the UE by initiating a mobile termination procedure.

[0074] Figure 3 shows the registration procedure for S-NSSAI according to NSAC, and EAC is deactivated in AMF.

[0075] The detailed process of the embodiment is described as follows.

[0076] 1. To perform an Early Admission Control (EAC) procedure, the NSACF may send an Nnsacf_NumberOfUEsPerSliceEACNotify message for the S-NSSAI to the AMF. If the NSACF may indicate an EAC flag set to "inactive" in the Nnsacf_NumberOfUEsPerSliceEACNotify message, it means that the EAC mode is deactivated. The EAC flag set to "inactive" may be referred to as an EAC flag set to "not active". This usually occurs when the number of UEs registered in the network slice is less than a certain operator-defined threshold. In this case, the AMF deactivates the EAC procedure. In one example, EAC is deactivated by default in the AMF.

[0077] 2. The UE initiates the registration procedure for the S-NSSAI by sending a Registration Request message including the S-NSSAI in the Request NSSAI.

[0078] 3. The AMF sends a registration acceptance message including the S-NSSAI to the authorized NSSAI.

[0079] 4. The AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF to register the UE for the S-NSSAI at the NSACF. The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message may include the S-NSSAI.

[0080] 5. When the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF, the AMF starts timer Tamf, and the AMF waits for a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF.

[0081] Note that step 3 and steps 4 and 5 may be performed in any order. For example, the AMF may send a registration acknowledgement message after sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message and before starting timer Tamf.

[0082] For example, the AMF may send a registration acknowledgement message after starting a timer Tamf.

[0083] 6. The AMF receives a Registration Complete message from the UE.

[0084] While Tamf is running, if the AMF receives a UL NAS transport message including a 5GSM message with an S-NSSAI registered in the NSACF, the AMF performs one of the following operations:

[0085] -The AMF rejects the 5GSM message when the response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message has not yet been confirmed.

[0086] -The AMF sends the 5GSM message contained in the UL TRANSPORT message to the SMF to approve and process the UL NAS transport message.

[0087] 7-8. If the timer Tamf expires in the AMF and the AMF has not received a response (e.g., a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message) from the NSACF, the AMF sends a NAS message to the UE including the S-NSSAI in the rejected NSSAI, a cause value indicating that the S-NSSAI is temporarily unavailable. The cause value may indicate that the S-NSSAI is temporarily unavailable due to congestion. The NAS message may include a value of the back-off timer. The NAS message may be one of the following messages:

[0088] The NAS message may be a deregistration request message. The AMF initiates a network-initiated deregistration procedure and sends a deregistration request message if the S-NSSAI is the only network slice (or the only entry) in the UE's allowed NSSAI list. The AMF may determine that the S-NSSAI is the only network slice (or the only entry) in the UE's allowed NSSAI list based on the UE context for the UE in the AMF. The deregistration request message includes the S-NSSAI in the rejected NSSAI with a cause value indicating that the network slice (or S-NSSAI) is temporarily unavailable. The deregistration request message may include a value of a back-off timer. If the timer Tamf expires in the AMF and the AMF has not received a response (e.g., a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message) from the NSACF, the AMF may initiate a network-initiated deregistration procedure.

[0089] -The NAS message may be a configuration update command message. The AMF initiates a general UE configuration update procedure and sends a configuration update command message including a rejected NSSAI including the S-NSSAI, a cause value indicating that the network slice (or S-NSSAI) is temporarily unavailable, and a back-off time value. If the UE enters an idle mode (e.g., when the N1 signaling connection is released) while the AMF is checking NSAC for the S-NSSAI, the AMF may first page the UE, and when the UE is connected again, the AMF updates the state of the S-NSSAI in the UE through a UE configuration update procedure. If an active PDU session for the S-NSSAI exists, the AMF initiates a PDU session release procedure for the active PDU session. If a timer Tamf expires in the AMF and the AMF has not received a response (e.g., a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message) from the NSACF, the AMF may initiate a general UE configuration update procedure. If timer Tamf expires in the AMF and the AMF has not received a response from the NSACF (e.g., a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message), the AMF may initiate a general UE configuration update procedure.

[0090] -The NAS message may be a registration acknowledgement message. If the AMF receives a new registration request message including the S-NSSAI in the request NSSAI, the AMF sends a registration acknowledgement message including the S-NSSAI in the reject NSSAI, a cause value indicating that the network slice is temporarily unavailable, and a value of the back-off timer. If the timer Tamf expires in the AMF and the AMF has not received a response (e.g., an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message) from the NSACF, and the AMF receives a new registration request message including the S-NSSAI in the request NSSAI from the UE, the AMF may send a registration acknowledgement message.

[0091] 9. When the UE receives the NAS message, the UE starts a timer T with a value set in the back-off timer value for the S-NSSAI. The UE does not initiate a registration procedure to register for the S-NSSAI in the network until the timer T expires. For example, if the back-off time value for the S-NSSAI is included in the NAS message, the UE starts a timer T with a value set in the back-off time value, and the UE does not initiate registration for the S-NSSAI with the network until the timer T expires. The back-off time value may be referred to as a value of the timer for stopping the registration procedure for the S-NSSAI. For example, the UE holds off the registration procedure for the S-NSSAI until the timer T expires.

[0092] When the UE receives the authorized NSSAI in the configuration update command message, the UE stores the received authorized NSSAI and performs the NAS procedure according to the stored authorized NSSAI.

[0093] 10. After the NAS message in step 8 is sent to the UE, when the AMF receives a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF, the AMF initiates one of the following procedures.

[0094] The AMF initiates a general UE configuration update procedure. The configuration update command message sent by the AMF during the general UE configuration update procedure includes an authorized NSSAI including the S-NSSAI.

[0095] For example, if the AMF receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the UE's registration for the S-NSSAI is successful, the AMF initiates a general UE configuration update procedure by sending a configuration update command message including an allowed NSSAI that includes the S-NSSAI.

[0096] 11. Upon receiving a Configuration Update Command message from the AMF, the UE stores the allowed NSSAIs and performs the NAS procedure accordingly. The UE removes the S-NSSAI from the rejected NSSAIs.

[0097] <First variant of the second aspect> In step 7 of Figure 3, if the AMF does not receive a response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message from the NSACF and the Tamf is terminated, the AMF may repeat sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF as shown in step 4 several times (e.g., the number of times is defined in the AMF by the standard or configured by the operator). If there is still no response from the NSACF, the AMF may continue from step 8 onwards.

[0098] For example, aspect 2 and the variant of aspect 2 propose solutions to some situations in a 3GPP node or in connections between 3GPP nodes during an NSAC procedure.

[0099] For example, aspect 2 and the variants of aspect 2 can solve prominent problems with respect to some situations in 3GPP nodes or connections between 3GPP nodes during NSAC procedures.

[0100] For example, embodiment 2 and the variants of embodiment 2 propose solutions to some situations where the 3GPP standard for NSAC procedures has some unclear descriptions for some situations.

[0101] For example, aspect 2 and a variant of aspect 2 can solve the problem that it is unclear how the AMF should handle the UE during the registration procedure if the Network Slice Admission Control Function (NSACF) does not respond to a request from the AMF.

[0102] <Third aspect> The third aspect discloses that the AMF changes the registration status of the S-NSSAI in the UE when the EAC flag is set to "active".

[0103] This aspect discloses the behavior of the AMF when the AMF receives a request from the NSACF to activate an EAC procedure for the S-NSSAI.

[0104] After the AMF sends a request to the NSACF to register the UE to the S-NSSAI at the NSACF during the registration procedure, NSACF If no response message is received from the UE, the aspect discloses that the AMF allocates an intermediate state for the S-NSSAI and sends the state in a registration accept message. The AMF further initiates an NSAC procedure to register the UE in the NSACF. Upon completion of the NSAC procedure, the NSACF updates the S-NSSAI to be allowed if the result of the NSAC procedure is successful, or rejected if the result of the NSAC procedure is not successful. The AMF initiates a NAS procedure to update the S-NSSAI state in the UE.

[0105] Figure 4 shows the behavior of the AMF when the AMF receives a registration request message including an S-NSSAI in the requested NSSAI, the S-NSSAI follows the NSAC, and an EAC is activated for the S-NSSAI in the AMF.

[0106] The detailed process of the embodiment is described as follows.

[0107] 1a. To perform an Early Admission Control (EAC) procedure, the NSACF may send an Nnsacf_NumberOfUEsPerSliceEACNotify message for the S-NSSAI to the AMF. If the NSACF may indicate an EAC flag set to "active" in the Nnsacf_NumberOfUEsPerSliceEACNotify message, it means that the EAC mode is activated. For example, the EAC flag set to "active" means that the EAC mode is activated in the NSACF. This usually occurs when the number of UEs registered in the network slice exceeds a certain operator-defined threshold (e.g., a percentage of the maximum number of UEs allowed to register in the network slice).

[0108] 1b. The NSACF determines that the number of UEs for the S-NSSAI has reached a maximum threshold for a long time (or a predetermined time) and no more UEs can be registered at the NSACF for the S-NSSAI. Then, the NSACF sends a Nnsacf_NumberOfUEsPerSliceEACNotify message or a new message including the S-NSSAI and information including an Information Element (IE) indicating that the number of UEs has reached the maximum threshold for the S-NSSAI (e.g., Overload Control information). The message optionally includes a backoff time value. Also, in one example, the NSACF sends the message when the NSACF receives a large number of messages related to the NSAC procedure from the AMF or SMF and the NSACF determines that the NSACF cannot process all of the messages and becomes overloaded. In this case, the NSACF may indicate in the message that the NSACF is overloaded. For example, the NSACF may indicate in the message that the NSACF is not reachable from the AMF.

[0109] For example, the NSACF may perform at least one of the processes in step 1a and step 1b.

[0110] 2. The UE initiates a registration procedure to register the UE to the S-NSSAI by sending a Registration Request message including the S-NSSAI in the Request NSSAI. The UE starts timer T3510.

[0111] 3-4. When EAC is activated for the UE (e.g., when the AMF receives a Nnsacf_NumberOfUEsPerSliceEACNotify message including an EAC flag set to "active"), or when the AMF receives a message from the NSACF indicating that the NSACF is overloaded, the number of UEs has reached the maximum value for the S-NSSAI, or the NSACF is not reachable by the AMF, the AMF sets the S-NSSAI state as pending for the NSAC registration procedure. The AMF sends a registration accept message including an NSAC registration pending NSSAI IE including the S-NSSAI to the UE. The registration accept message may include a back-off timer value.

[0112] The NSAC-REGISTRATION PENDING NSSAI IE includes an S-NSSAI for which registration to the NSACF is pending because the AMF is waiting for the result of the UE's registration procedure for the S-NSSAI to the NSACF, or an S-NSSAI for which registration of the UE to the NSACF is temporarily not possible due to the reasons listed above in this step. For example, the reasons may include that there are many messages related to the NSAC procedure and the NSACF is overloaded and cannot process all of the messages, or the NSACF is not reachable from the AMF. The NSAC-REGISTRATION PENDING NSSAI IE may be referred to as information indicating that registration of the UE to the S-NSSAI to the NSACF is pending.

[0113] Upon receiving the Registration Accept message, the UE stores the NSAC-Registration Pending NSSAI IE. The UE does not initiate a registration procedure to register the UE for the S-NSSAI present in the NSAC-Registration Pending IE. The UE does not initiate a 5GSM procedure to establish a PDU session for the S-NSSAI present in the NSAC-Registration Pending IE.

[0114] For example, upon receiving a registration accept message, the UE stores the NSAC-REGISTRATION-PENDING-NSSAI IE and starts a timer with a value set to the value of the back-off timer received in the registration accept message, and the UE does not initiate a registration procedure to register the UE for the S-NSSAI present in the NSAC-REGISTRATION-PENDING-IE while the timer is running. In addition, for example, the UE does not initiate a 5GSM procedure to establish a PDU session for the S-NSSAI present in the NSAC-REGISTRATION-PENDING-IE while the timer is running. The back-off time value may be referred to as the value of the timer to stop the procedure for the S-NSSAI.

[0115] 5. If the AMF receives a registration request message (e.g., the UE does not receive a response to the registration request message sent in step 2 and the timer T3511 expires, the UE retries the registration request message), the AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF to process the S-NSSAI to register the UE to the NSACF. For example, the registration request message may include the S-NSSAI in the request NSSAI and may be sent from the UE after the timer started in step 4 expires. For example, the registration request message may include the S-NSSAI in the request NSSAI and may be sent from the UE after the timer started in step 4 expires. 2 The registration request message may be sent from a different UE than the UE that sends the registration request message.

[0116] If the AMF receives the message in step 1b, the AMF does not send an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF for S-NSSAI.

[0117] The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message may include an S-NSSAI and an update flag set to "increase". The update flag set to "increase" may indicate that the AMF requests to increase the number of UEs for the S-NSSAI. The update flag set to "increase" may be interpreted as a request to increase the number of UEs for the S-NSSAI.

[0118] Note that steps 3 and 4 and step 5 may be performed in any order. For example, the AMF processes in step 5 and then steps 3 and 4.

[0119] 6. The UE sends a registration complete message to the AMF. For example, if the UE receives the registration acknowledgement message in step 4, the UE sends a registration complete message.

[0120] 7. The AMF receives the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF, and performs one of the following actions in steps 8a and 8b depending on whether the UE registration is successful:

[0121] 8a. If the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicates that the UE is successfully registered with the NSACF for the S-NSSAI, the AMF sends a first NAS message to the UE including the S-NSSAI in the allowed NSSAI list. The first NAS message may be a registration accept message or a configuration update command message.

[0122] 8b. If the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message indicates that the UE is not successfully registered to the NSACF for the S-NSSAI, the AMF sends a second NAS message to the UE including the S-NSSAI in the Rejected NSSAI with a cause value indicating that the maximum number of UEs has been reached and a value of the back-off timer. The second NAS message may be a Deregistration message, a Deregistration Request message, a Configuration Update Command message, or a Registration Acknowledgement message.

[0123] 9. Upon receiving the first NAS message, the UE removes the S-NSSAI from the NSAC-Registration Pending NSSAI IE. The UE stores the S-NSSAI in the Allowed NSSAI and may perform the NAS procedure via the S-NSSAI.

[0124] Upon receiving the second NAS message, the UE starts a timer T with a value set to the back-off timer value. The UE does not start a registration procedure to register the UE for the S-NSSAI while the timer T is running. The back-off time value may be referred to as a value of the timer for stopping the registration procedure for the S-NSSAI. For example, the UE holds off the registration procedure for the S-NSSAI until the timer T expires.

[0125] <First variant of the third aspect> In one example, the NSAC registration pending NSSAI IE is the same as the pending NSSAI defined in Non-Patent Document 6.

[0126] For example, aspect 3 and the variants of aspect 3 propose solutions to some situations in a 3GPP node or in connections between 3GPP nodes during an NSAC procedure.

[0127] For example, aspect 3 and the variants of aspect 3 can solve prominent problems with respect to some situations in 3GPP nodes or connections between 3GPP nodes during NSAC procedures.

[0128] For example, embodiment 3 and its variants propose solutions to some situations where the 3GPP standard for NSAC procedures has some unclear descriptions for some situations.

[0129] For example, aspect 3 and a variant of aspect 3 can solve the problem that it is unclear how the AMF should handle the UE during the registration procedure if the Network Slice Admission Control Function (NSACF) does not respond to a request from the AMF.

[0130] <Fourth aspect> The fourth aspect discloses a PDU session establishment procedure in the case where the NSACF does not respond.

[0131] This aspect discloses the behavior of the SMF when the SMF does not receive a response from the NSACF to a request to increase the number of PDU sessions for the S-NSSAI.

[0132] This aspect discloses that during a PDU session establishment procedure, if the SMF does not receive a response to a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message for the S-NSSAI within a certain period of time, the SMF rejects the PDU session establishment procedure for the S-NSSAI and sends a PDU session establishment reject message with a 5GSM cause value set to an existing value (e.g., 5GSM#69) or a new value indicating no response from the NSACF. The PDU session establishment reject message includes a back-off timer value. When the UE receives the PDU session establishment reject message, the UE starts a timer T with a value set to the back-off timer value, and the UE does not start a PDU session establishment procedure for the S-NSSAI. The back-off time value may be referred to as a value of the timer for stopping the procedure of establishing a PDU session for the S-NSSAI.

[0133] Figure 5 shows that SMF NSACF This shows the behavior of the SMF when no response is received from the

[0134] The detailed process of the embodiment is described as follows.

[0135] 1. The UE registers with the PLMN via the S-NSSAI in the authorized NSSAI.

[0136] 2. The UE initiates the PDU session establishment procedure as described in 3GPP TS 21.2006.02.02 for the S-NSSAI by sending a PDU session establishment request message containing the S-NSSAI.

[0137] 3. When the SMF receives the PDU Session Establishment Request message for the S-NSSAI, the SMF sends a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF to increase the number of PDU sessions for the S-NSSAI. The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and an update flag set to "increase". The update flag set to "increase" may indicate that the SMF requests to increase the number of PDU sessions for the S-NSSAI. The update flag set to "increase" may be interpreted as a request to increase the number of PDU sessions for the S-NSSAI.

[0138] If the SMF determines that the NSACF is not contactable for the S-NSSAI or if the NSACF sends a message to the SMF indicating that the NSACF is currently overloaded and will not accept any request messages, the SMF does not send an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message for the S-NSSAI to the NSACF.

[0139] For example, if the NSACF is receiving a large number of messages related to the NSAC procedure from the AMF or SMF and the NSACF determines that it cannot process all of the messages and will become overloaded, the NSACF sends a message indicating that the NSACF is now overloaded and will not accept any request messages. For example, the SMF determines or recognizes that the NSACF for the S-NSSAI is not contactable or is overloaded, the SMF may not send a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message for the S-NSSAI to the NSACF and may proceed to step 6.

[0140] 4. When the SMF sends a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF, the SMF starts a timer Tsmf and the SMF waits for a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF.

[0141] 5-6. If timer Tsmf expires in the SMF and the SMF has not received a response from the NSACF (e.g., a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message) or the SMF determines that the SMF is not reachable, the SMF sends a PDU Session Establishment Reject message to the UE, the PDU Session Establishment Reject message including a 5GSM Cause value set to an existing value (e.g., 5GSM#69) or a new value indicating no response from the NSACF. The PDU Session Establishment Reject message includes the value of the back-off timer.

[0142] For example, if the SMF does not send a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message for S-NSSAI to the NSACF in step 3, the SMF sends a PDU Session Establishment Reject message to the UE.

[0143] 7. Upon receiving the PDU Session Establishment Reject message, the UE starts a timer T (an existing SM timer or a new timer), and the UE does not start any PDU session establishment procedure for the S-NSSAI until timer T expires. Timer T has a value corresponding to the value received in the PDU Session Establishment Reject message. This value may be referred to as the value of the timer for stopping the procedure to establish a PDU session for the S-NSSAI. For example, the UE reserves any PDU session establishment procedure for the S-NSSAI until timer T expires.

[0144] 8. When the SMF receives a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message indicating a successful operation (e.g., success in increasing the number of PDU sessions for the S-NSSAI), the SMF performs one of the following operations in steps 9a-1 and 9b: The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message may indicate successful registration or counting of PDU sessions for the S-NSSAI. The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message may indicate that the number of PDU sessions for the S-NSSAI was successfully increased.

[0145] 9a-1. The SMF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message with the S-NSSAI and the update flag set to "reduce". The update flag set to "reduce" may indicate that the AMF requests to reduce the number of PDU sessions for the S-NSSAI. The update flag set to "reduce" may be interpreted as a request to reduce the number of PDU sessions for the S-NSSAI.

[0146] 9a-2.When an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message is received, NSACFreduces the number of PDU sessions for the S-NSSAI and sends a message, for example, an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message. The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message may indicate success in reducing the number of PDU sessions for the S-NSSAI. The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message may indicate that the number of PDU sessions for the S-NSSAI was successfully reduced.

[0147] 9b. The SMF initiates a network-triggered service request procedure as described in non-patent document 3 to establish the PDU session that was rejected in step 6.

[0148] <First variant of the fourth aspect> In one example, the UE retries the PDU session establishment procedure by sending a PDU session establishment request message for the same combination of S-NSSAI and DNN after expiration of a retry timer (e.g., timer T).

[0149] When the SMF receives the PDU Session Establishment Request message, it sends a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message for the S-NSSAI to the NSACF. If there is no response from the NSACF to the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message, the SMF sends another Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message to increase the number of PDU sessions for the S-NSSAI. NSACF Do not send to NSACF Wait for a response from

[0150] In one example, if the SMF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message with the update flag set to "increase" and receives a response indicating successful operation of the NSAC, the SMF proceeds with the PDU session establishment procedure. For example, if the SMF receives a response indicating successful operation of the NSAC (e.g., a response indicating that the number of PDU sessions for the S-NSSAI has been successfully increased) after sending the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message of step 3 in Figure 5, the SMF proceeds with the PDU session establishment procedure.

[0151] For example, embodiment 4 and the variant of embodiment 4 propose solutions to some situations in a 3GPP node or in connections between 3GPP nodes during an NSAC procedure.

[0152] For example, aspect 4 and the variants of aspect 4 can solve prominent problems with respect to some situations in 3GPP nodes or connections between 3GPP nodes during NSAC procedures.

[0153] For example, embodiment 4 and the variants of embodiment 4 propose solutions to some situations where the 3GPP standard for NSAC procedures has some unclear descriptions for some situations.

[0154] For example, aspect 4 and a variant of aspect 4 can solve the problem that it is unclear how the SMF should handle a PDU session during a PDU session establishment procedure if the Network Slice Admission Control Function (NSACF) does not respond to a request from the SMF.

[0155] <System Overview> FIG. 6 illustrates generally a telecommunications system 1 for mobile (cellular or wireless) devices (known as user equipment (UE)) to which the above aspects are applicable.

[0156] The telecommunication 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.

[0157] The (R)AN node 5 supports any radio access, including 5G radio access technology (RAT), E-UTRA radio access technology, Beyond 5G RAT, 6G RAT, and non-3GPP RAT including wireless local area network (WLAN) technologies as defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0158] The (R)AN node 5 may be separated into a Radio Unit (RU), a Distributed Unit (DU), and a Centralized Unit (CU), which in some aspects may be connected together to build the (R)AN node 5 by adopting an architecture as defined by the Open RAN (O-RAN) Alliance, and the above units are referred to as O-RU, O-DU, and O-CU, respectively.

[0159] The (R)AN node 5 may be separated into one or more control plane functions and one or more 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 in each user plane function being aggregated at both the UE 3 and the (R)AN node 5. Such a separated architecture may be referred to as "dual connectivity" or "multi-connectivity."

[0160] The (R)AN node 5 may also support communications using satellite access. In some aspects, the (R)AN node 5 may support satellite and terrestrial access.

[0161] In addition, the (R)AN node 5 may also be referred to as an access node for non-wireless access, including fixed access as defined by the Broadband Forum (BBF) and optical access as defined by the Innovative Optical and Wireless Network (IOWN).

[0162] The core network 7 may include logical nodes (or "functions") that support 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 in 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).

[0163] By applying network virtualization technologies such as those defined by the European Telecommunications Standards Institute, Network Functions Virtualization (ETSI NFV), network functions can be deployed as distributed, redundant, stateless, and scalable, providing services from several locations and providing several execution instances at each location.

[0164] The core network 7 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0165] As is known, when the UE 3 is moving around the geographic area covered by the telecommunication system 1, the UE 3 may move in and out of areas (i.e., radio cells) served by the (R)AN nodes 5. To keep track of the UE 3 and facilitate movement between the various (R)AN nodes 5, the core network 7 comprises at least one access and mobility management function (AMF) 70. The AMF 70 communicates with the (R)AN nodes 5 connected to the core network 7. In some core networks, a mobility management entity (MME) or mobility management node for Beyond 5G or a mobility management node for 6G may be used instead of the AMF 70.

[0166] The core network 7 also includes, among others, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, a Network Exposure Function (NEF) 74, a Unified Data Management (UDM) 75, a Network Data Analytics Function (NWDAF) 76, and a Network Slice Admission Control Function (NSACF) 77. When a UE 3 roams into a visited Public Land Mobile Network (VPLMN), the home Public Land Mobile Network (HPLMN) of the UE 3 provides the UDM 75 and at least some of the functionality of the SMF 71, UPF 72, and PCF 73 to the roaming-out UE 3.

[0167] The UE 3 and the respective serving (R)AN node 5 are connected via an appropriate air interface (e.g., the so-called "Uu" interface and / or the like). Neighboring (R)AN nodes 5 are connected to each other via appropriate (R)AN node 5 to (R)AN node interfaces (such as the so-called "Xn" interface and / or the like). Each (R)AN node 5 is also connected to nodes in the core network 7 (such as the so-called core network nodes) via appropriate interfaces (such as the so-called "N2" / "N3" interfaces and / or the like). From the core network 7, a connection is also provided to a data network 20. The data network 20 may be the Internet, a public network, an external network, a private network, or an internal network of the 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 may be connected to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or unstructured data types.

[0168] The "Uu" interface may include a control plane and a user plane.

[0169] 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 physical connections.

[0170] 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 connections.

[0171] For example, the following messages are communicated at the RRC layer to support AS signaling:

[0172] - 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, any of the following parameters may be included together in the RRC Setup Request message: --establishmentCause and ue-Identity. ue-Identity may have the value of ng-5G-S-TMSI-Part1 or a random Value.

[0173] - 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, any of the following parameters may be included together in the RRC Setup message: --masterCellGroup (master cell group) and radioBearerConfig (radio bearer configuration)

[0174] - 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, any of 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

[0175] The UE 3 and the AMF 70 are connected via a suitable interface (e.g., a so-called N1 interface and / or the like). 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 in 3GPP access and non-3GPP access. For example, the following messages are communicated in the N1 interface:

[0176] 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, any of the following parameters may be included together in the Registration Request message: --5GS registration type, ngKSI, 5GS mobile identity, Non-current native NAS key set identifier, 5GMM capability, UE security capability, Requested NSSAI, Last visited registered TAI, S1 UE network capability, Uplink data status, PDU session status, MICO indication, UE status, Additional GUTI, Allowed PDU session status, UE's usage setting, Requested DRX parameters, EPS NAS message container, LADN indication, Payload container type, Payload container container, Network slicing indication, 5GS update type, Mobile station classmark 2, Supported codecs, NAS message container, EPS bearer context status, Requested extended DRX parameters, T3324 value, UE radio capability IDThe requested NB-N1 mode DRX parameters include: Requested NB-N1 mode Routing Information Requested ID, Requested mapped NSSAI, Additional information requested, Requested WUS assistance information, N5GC indication, and Requested NB-N1 mode DRX parameters.

[0177] - 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, any of the following parameters may be included together in the Registration Accept message: --5GS registration result, 5G-GUTI, Equivalent PLMNs, TAI list, Allowed NSSAI, Rejected NSSAI, Configured NSSAI, 5GS network feature support, PDU session status, PDU session reactivation result, PDU session reactivation result error cause, LADN information, MICO indication, Network slicing indication, Service area list, T3512 value, Non-3GPP de-registration timer value, T3502 value, Emergency number list list, Extended emergency number list, SOR transparent container, EAP message, NSSAI inclusion mode, Operator-defined access category definitions, Negotiated DRX parameters, Non-3GPP NW policies, EPS bearer context status, Negotiated extended DRX parameters, T3447 value, T3448 valueThe following are the received 5G-S-TMSI status information: T3324 value, T3324 value, UE radio capability ID, UE radio capability ID deletion indication, Pending NSSAI, Ciphering key data, CAG information list, Truncated 5G-S-TMSI configuration, Negotiated WUS assistance information, Negotiated NB-N1 mode DRX parameters, and Extended rejected NSSAI.

[0178] - 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.

[0179] -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, any of 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.

[0180] -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, any of the following parameters may be present together in the Authentication Response message: --Authentication response message identity, Authentication response parameter, and EAP message.

[0181] -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, any of the following parameters may be present together in the Authentication Result message: --ngKSI, EAP Messages, and ABBA.

[0182] -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, any of the following parameters may be present together in the Authentication Failure message: --Authentication failure message identity, 5GMM cause, and Authentication failure parameter.

[0183] -Authentication Reject 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 present together in the Authentication Reject message: --EAP messages.

[0184] - 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, any of the following parameters may be present together in the Service Request message: --ngKSI, Service type, 5G-S-TMSI, Uplink data status, PDU session status, Allowed PDU session status, NAS message container.

[0185] - Service 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, any of the following parameters may be present together in the Service Accept message: --PDU session status, PDU session reactivation result, PDU session reactivation result error cause, EAP message, and T3448 value.

[0186] - Service Reject 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, any of the following parameters may be present together in the Service Reject message: --5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list.

[0187] -Configuration Update Command message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, any of the following parameters may be present together in the Configuration Update Command message: --Configuration update indication, 5G-GUTI, TAI list, Allowed NSSAI, Service area list, Full name for network, Short name for network, Local time zone, Universal time and local time zone, Network daylight saving time, LADN information, MICO indication, Network slicing indication, Configured NSSAI, Rejected NSSAI, Operator-defined access category definitions, SMS indication, T3447 value, CAG information list, UE radio capability ID, UE radio capability ID deletion The following messages are displayed: 5GS registration result, 5GS registration indication, 5GS registration result, Truncated 5G-S-TMSI configuration, Additional configuration indication, and Extended rejected NSSAI.

[0188] -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 present together in the Configuration Update Complete message: --Configuration update complete message identity.

[0189] <User equipment (UE)> FIG. 7 is a block diagram showing the main components of a UE 3 (mobile device 3). As shown, the UE 3 includes a transceiver circuit 31 operable to transmit signals to and receive signals from a connection node via one or more antennas 32. In addition, the UE 3 may include a user interface 34 for inputting information from the outside or outputting information to the outside. Although not necessarily shown in the figure, 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 appropriate. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The controller 33 controls the operation of the UE 3 according to the software stored in the memory 36. The software includes, among other things, an operating system 361 and a communication control module 362 having at least a transceiver control module 3621. The communication control module 362 (using its transceiver control module 3621) controls the UE 3, the (R)AN node 5, and the AMF 70The controller 33 is responsible for processing (generating / sending / receiving) signaling and uplink / downlink data packets between the controller 33 and other nodes such as the UE 3, the UE 4, the UE 5, the UE 6, the UE 7, the UE 8, the UE 9, the UE 10, the UE 11, the UE 12, the UE 13, the UE 14, the UE 15, the UE 16, the UE 17, the UE 18, the UE 19, the UE 20, the UE 21, the UE 22, the UE 23, the UE 24, the UE 25, the UE 26, the UE 27, the UE 28, the UE 29, the UE 30, the UE 31, the UE 32, the UE 333, the UE 334, the UE 355, the UE 356, the UE 357, the UE 358, the UE 359, the UE 351, the UE 352, the UE 353, the UE 354, the UE 3555, the UE 35555, the UE 35556, the UE 3557, the UE 3558, the UE 359, the UE 35 ...

[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 NPN (PNI-NPN).

[0191] UE3 may be, for example, an item of production or manufacturing equipment and / or an item of energy-related machinery (e.g., equipment or machines such as boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal generators, nuclear generators, batteries, nuclear systems and / or related equipment, heavy electrical machinery, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metal processing machines, manipulators, robots and / or application systems thereof, tools, moulds or dies, rolls, conveying equipment, lifting equipment, material handling equipment, textile machinery, sewing machines, printing machines and / or related machines, paper converting machines, chemical machinery, mining machinery and / or construction machinery and / or related equipment, agricultural, forestry and / or fishing machinery and / or implements, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, fittings, and / or application systems for any of the foregoing equipment or machines).

[0192] UE 3 may be, for example, an item of transportation equipment (e.g., vehicles, automobiles, motorbikes, bicycles, trains, buses, carts, rickshaws, ships and other watercraft, aircraft, rockets, satellites, drones, balloons, etc.).

[0193] UE 3 may be, for example, an item of information and communications equipment (eg, 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 refrigeration machine, a refrigeration machine application product, an item of commercial and / or service industry equipment, a vending machine, an automated service machine, an office machine or equipment, consumer electronic devices and appliances (e.g., consumer electronic appliances such as audio equipment, video equipment, loudspeakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, electronic fans or related appliances, 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, a power application device, etc.).

[0196] UE3 may be, for example, an electronic lamp, a lighting fixture, a measuring instrument, an analyzer, a tester, or a surveying or detecting device (e.g., a smoke alarm, a occupancy alarm sensor, a motion sensor, a radio tag, or other surveying or detecting device), a watch or clock, laboratory equipment, optical equipment, medical equipment and / or systems, a weapon, an item of cutlery, a hand tool, or the like.

[0197] UE 3 may be, for example, a wireless-equipped personal digital assistant or related equipment (such as a wireless card or module designed to be attached to or inserted into another electronic device (eg, a personal computer, electrical measurement machine)).

[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") may be equipped with appropriate electronics, software, sensors, network connectivity, and / or the like, allowing them to collect and exchange data with each other and with other communicating devices. IoT devices may comprise automated machines that follow software instructions stored in internal memory. IoT devices may operate without the need for human supervision or interaction. IoT devices may also remain stationary and / or stopped for long periods of time. IoT devices may be implemented as part of a (generally) stationary apparatus. IoT devices may also be incorporated into non-stationary apparatus (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 transmit / 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 is sometimes also referred to as a Machine-Type Communication (MTC) device or a Machine-to-Machine (M2M) communication device, or a Narrow Band-IoT UE (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 vehicle, a vehicular device, a motorcycle, or a Vehicle to Everything (V2X) 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. 8 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, base station for Beyond 5G, base station for 6G). As shown, the (R)AN node 5 includes a transceiver circuit 51 operable to transmit signals to and receive signals from an attached UE 3 via one or more antennas 52, and to transmit signals to and receive signals from other network nodes via a network interface 53 (directly or indirectly). A controller 54 controls the operation of the (R)AN node 5 according to software stored in a memory 55. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (e.g., RMD). The software includes, among other things, an operating system 551 and a communication control module 552 having at least a transceiver control module 5521.

[0205] The communication control module 552 (using its transceiver control sub-module) is responsible for (e.g., directly or indirectly) handling (generating / sending / receiving) signaling between the (R)AN node 5 and other nodes, such as the UE 3, another (R)AN node 5, the AMF 70, and the UPF 72. The signaling may include, for example, appropriately formatted signaling messages (e.g., RRC connection establishment messages and other RRC messages), NG Application Protocol (NGAP) messages (i.e., messages over the N2 reference point), Xn application protocol (XnAP) messages (i.e., messages over the Xn reference point), etc., relating to the radio connection and connectivity with the core network 7 (for a particular UE 3), in particular connection establishment and maintenance. Such signaling may also include, in case of transmission, for example, broadcast information (e.g., master information and system information).

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

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

[0208] <System overview of (R)AN node 5 based on the O-RAN architecture> FIG. 9 schematically shows (R)AN node 5 based on the O-RAN architecture to which the (R)AN node 5 aspect is applicable.

[0209] The (R)AN node 5 based on the O-RAN architecture represents a system overview in which the (R)AN node is separated into a Radio Unit (RU) 60, a Distributed Unit (DU) 61, and a Centralized Unit (CU) 62. In some aspects, the units may be combined. For example, the RU 60 may be combined / combined with the DU 61 as a combined / combined unit, and the DU 61 may be combined / 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) may be implemented in the combined / combined unit above. Furthermore, the CU 62 may be separated into two functional units, such as a CU Control plane (CP) and a CU User plane (UP). The CU CP has a control plane function in the (R)AN node 5. The CU UP has a user plane function in the (R)AN node 5. Each CU CP is connected to a CU UP via a suitable interface (such as a so-called "E1" interface and / or the like).

[0210] The UE 3 and the respective serving RU 60 are connected via a suitable air interface (e.g., a so-called "Uu" interface and / or the like). Each RU 60 is connected to a DU 61 via a suitable interface (such as a so-called "fronthaul", "open fronthaul", "F1" interface and / or the like). Each DU 61 is connected to a CU 62 via a suitable interface (such as a so-called "midhaul", "open midhaul", "E2" interface and / or the like). Each CU 62 is also connected to a node in the core network 7 (such as a so-called core network node) via a suitable interface (such as a so-called "backhaul", "open backhaul", "N2" / "N3" interface and / or the like). In addition, the user plane part of the DU 61 may also be connected to the core network node 7 via a suitable interface (such as a so-called "N3" interface and / or the like).

[0211] Depending on the functionality divided between the RU 60, the DU 61, and the CU 62, each unit provides a part 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 layer and the RLC layer, and the CU 62 may provide functionality for supporting the PDCP layer, the SDAP layer, and the RRC layer.

[0212] <Radio Unit (RU)> FIG. 10 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, base station for Beyond 5G, base station for 6G). As shown, the RU 60 includes a transceiver circuit 601 operable to transmit signals to and receive signals from an attached UE 3 via one or more antennas 602, and to transmit and receive signals to and from other network nodes or portions via a network interface 603 (directly or indirectly). A controller 604 controls the operation of the RU 60 according to software stored in memory 605. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (e.g., 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 communication control module 6052 (using its transceiver control sub-module) is responsible for handling (generating / sending / receiving) signaling between (e.g., directly or indirectly) the RU 60 and other nodes or parts, such as the UE 3, another RU 60, and the DU 61. The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connectivity with the RU 60 (for a particular UE 3), in particular the MAC and RLC layers.

[0214] When implemented, the controller 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 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0216] As described above, the RU 60 may be integrated / combined with the DU 61 as an integrated / combined unit. Any function described for the RU 60 may be implemented in the integrated / combined unit.

[0217] <Distributed Unit (DU)> FIG. 11 is a block diagram illustrating the main components of an exemplary DU 61, e.g., the DU portion of a base station (eNB in ​​LTE, gNB in ​​5G, base station for Beyond 5G, base station for 6G). 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 according to software stored in memory 614. For example, the software may be pre-installed in memory 614 and / or downloaded 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 6141 and a communication control module 6142 having at least a transceiver control module 61421. The communication control module 6142 (using its transceiver control module 61421) is responsible for 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 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

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

[0220] <Centralized Unit (CU)> FIG. 12 is a block diagram illustrating the main components of an exemplary CU 62, e.g., a CU portion of a base station (eNB in ​​LTE, gNB in ​​5G, base station for Beyond 5G, base station for 6G). As shown, the device includes a transceiver circuit 621 operable to transmit signals to and receive signals from other nodes or units (including DU 61) via a network interface 622. A controller 623 controls the operation of the CU 62 according to software stored in a memory 624. For example, the software may be pre-installed in the memory 624 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software includes, among other things, an operating system 6241 and a communication control module 6242 having at least a transceiver control module 62421. The communication control module 6242 (using its transceiver control module 62421) 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 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

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

[0223] <amf> 13 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 UE 3) via a network interface 702. A controller 703 controls the operation of the AMF 70 according to software stored in a memory 704. For example, the software may be pre-installed in the memory 704 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software includes, among other things, an operating system 7041 and a communication control module 7042 having at least a transceiver control module 70421. The communications control module 7042 (using its transceiver control module 70421) is responsible for handling (generating / sending / receiving) signaling between the AMF 70 and the UE 3 (e.g., via (R)AN node 5) and other nodes, such as 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) relating to access and mobility management procedures (for the UE 3).

[0224] The AMF 70 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0225] <smf> 14 is a block diagram illustrating the main components of the SMF 71. As shown, the device includes a transceiver circuit 711 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 712. A controller 713 controls the operation of the SMF 71 according to software stored in a memory 714. For example, the software may be pre-installed in the memory 714 and / or downloaded via a telecommunications network or from a removable memory device (RMD). The software includes, among other things, an operating system 7141 and a communication control module 7142 having at least a transceiver control module 71421. The communications control module 7142 (using its transceiver control module 71421) is responsible for handling (generating / sending / receiving) signaling between the SMF 71 and other nodes, such as the UPF 72 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., Hypertext Transfer Protocol (HTTP) RESTful methods based on a service-based interface) relating to session management procedures (for the UE 3).

[0226] SMF 71 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0227] <upf> 15 is a block diagram illustrating the main components of the UPF 72. As shown, the device includes a transceiver circuit 721 operable to transmit signals to and receive signals from other nodes (including the SMF 71) via a network interface 722. A controller 723 controls the operation of the UPF 72 according to software stored in a memory 724. For example, the software may be pre-installed in the memory 724 and / or downloaded 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 7241 and a communication control module 7242 having at least a transceiver control module 72421. The communications control module 7242 (using its transceiver control module 72421) is responsible for handling (generating / sending / receiving) signaling between the UPF 72 and other nodes, such as the SMF 71 and other core network nodes (including core network nodes in the HPLMN of the UE 3 when the UE 3 is roaming in). Such signaling may include, for example, appropriately formatted signaling messages (e.g., GPRS Tunneling Protocol (GTP) for the user plane) relating to user data processing (for the UE 3).

[0228] The UPF 72 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0229] <pcf> 16 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 according to software stored in a memory 734. For example, the software may be pre-installed in the memory 734 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software includes, among other things, an operating system 7341 and a communication 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 signaling messages (e.g. HTTP RESTful methods based on service-based interfaces) relating to policy management procedures (for the UE 3).

[0230] The PCF 73 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0231] <nef> 17 is a block diagram illustrating the main components of the NEF 74. As shown, the device includes a transceiver circuit 741 operable to transmit signals to and receive signals from other nodes (including UDM 75) via a network interface 742. A controller 743 controls the operation of the NEF 74 according to software stored in memory 744. For example, the software may be pre-installed in the memory 744 and / or downloaded over 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 NEF 74 and other nodes, such as the UDM 75 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 RESTful methods based on service-based interfaces) related to network exposure function procedures (for the UE 3).

[0232] The NEF 74 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0233] <udm> 18 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. For example, the software may be pre-installed in the memory 754 and / or downloaded over 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 7541 and a communication control module 7542 having at least a transceiver control module 75421. The communications control module 7542 (using its transceiver control module 75421) is responsible for handling (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 (e.g., HTTP RESTful methods based on service-based interfaces) relating to mobility management procedures (for the UE 3).

[0234] The UDM 75 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0235] <nedaf> 19 is a block diagram illustrating the main components of the NWDAF 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 NWDAF 76 according to software stored in a memory 764. For example, the software may be pre-installed in the memory 764 and / or downloaded over 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 7641 and a communication control module 7642 having at least a transceiver control module 76421. The communications control module 7642 (using its transceiver control module 76421) is responsible for handling (generating / sending / receiving) signaling between the NWDAF 76 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 RESTful methods based on service-based interfaces) related to network data analysis function procedures (for the UE 3).

[0236] The NWDAF 76 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0237] <nsacf> 20 is a block diagram illustrating the main components of the NSACF 77. As shown, the device includes a transceiver circuit 771 operable to transmit signals to and receive signals from other nodes (including the AMF 70, the SMF 71, and the SMF+PGW-C) via a network interface 772. A controller 773 controls the operation of the NSACF 77 according to software stored in a memory 774. For example, the software may be pre-installed in the memory 774 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7741 and a communication control module 7742 having at least a transceiver control module 77421. The communications control module 7742 (using its transceiver control module 77421) is responsible for handling (generating / sending / receiving) signaling between the NSACF 77 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 RESTful methods based on a service-based interface) relating to network data analysis function procedures (for the UE 3).

[0238] The NSACF 77 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0239] <Modifications and Replacements> Detailed embodiments have been described above. Still, those skilled in the art will appreciate that numerous modifications and alternatives may be made to the above embodiments while having the benefit of the disclosure embodied herein. Merely by way of example, numerous such alternatives and modifications are now described.

[0240] In the above description, the UE 3 and network devices are described for ease of understanding as having a number of separate modules (such as a communications control module). These modules may thus be provided for certain applications, for example where an existing system is modified to implement the present disclosure, and in other applications, for example in a system designed with the inventive features in mind from the beginning, but these modules may not be recognizable as separate entities, as they may be built into an overall operating system or code. These modules may also be implemented in software, hardware, firmware, or a mixture of these.

[0241] Each controller may include any suitable form of processing circuitry, including, 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, communications buses (e.g., control buses, data buses, and / or address buses), direct memory access (DMA) facilities, hardware or software implemented counters, pointers and / or timers, and / or the like.

[0242] In the above embodiment, a number of software modules have been described. Those skilled in the art will appreciate that the software modules may be provided in compiled or uncompiled form and may be provided to the UE 3 and the network device as a signal in a computer network or on a recording medium. Furthermore, the functions performed by some or all of the software may be performed using one or more dedicated hardware circuits. However, the use of software modules to update the functions of the UE 3 and the network device is preferred because the software modules facilitate the updating of the UE 3 and the network device.

[0243] In the above embodiment, 3GPP wireless communication (radio access) technology is used. However, any other wireless communication technology (e.g., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed line communication technology (e.g., BBF access, cable access, optical access, etc.) can also be used according to the above embodiment.

[0244] Items of user equipment may include communication devices such as, for example, mobile phones, smartphones, user equipment, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, and / or the like. Such mobile (and even 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, the present application refers to mobile devices (or UEs) in the description, but it will be understood that the described techniques may be implemented on any (mobile and / or generally fixed) communication device that may connect to a communication network to transmit / receive data, regardless of whether such communication device is controlled by human input or by software instructions stored in memory.

[0245] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0246] All or part of the exemplary aspects of the above disclosure may be described as follows, but are not limited to the following.

[0247] 4.2.11.2 Procedure for checking and updating availability of number of UEs per network slice

[0248] The availability check and update procedure for the number of UEs per network slice updates (i.e., increases or decreases) the number of UEs registered in the S-NSSAI that are subject to NSAC. The AMF is configured with information indicating which network slices are subject to NSAC.

[0249] Figure 4.2.11.2-1: Procedure for checking and updating the availability of the number of UEs per network slice (see Figure 21)

[0250] 1. If the AMF does not know which NSACF to communicate to, it performs an NSACF discovery as described in clauses 6.3.22 and 5.2.7.3.2 of TS 23.501 [2]. The AMF triggers the availability check and update procedure for the number of UEs per network slice to update the number of UEs registered in the network slice if the network slice according to the NSAC is included in the authorized NSSAI (i.e., the AMF requests the UE to register in the S-NSSAI) or is removed from the authorized NSSAI for the UE. Trigger events in the AMF also include a change in the authorized NSSAI in case of inter-AMF mobility. The procedure is triggered in the following cases:

[0251] -UE registration procedure (including registration type of initial registration or mobility registration update in inter-AMF mobility in CM-CONNECTED or CM-IDLE state) according to clause 4.2.2.2.2 - if EAC mode is active, before registration approval in step 21, or -After the registration approval message if EAC mode is not active

[0252] - In the UE deregistration procedure, after the deregistration procedure is completed, according to clause 4.2.2.3

[0253] In a UE configuration update procedure (which may occur as a result of an NSSAA procedure or a change in the subscribed S-NSSAI) - before a UE configuration update message if EAC mode is active, or - after a UE CONFIGURATION UPDATE message if EAC mode is not active

[0254] Note 1: Depending on the deployment, there may be different NSACFs for different S-NSSAIs following NSAC, so during registration, the AMF triggers the availability check and update procedure of the number of UEs per network slice to multiple NSACFs.

[0255] 2. The AMF sends a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF. The AMF includes in the message the UE ID, the access type, the S-NSSAI, and an update flag indicating whether the number of UEs registered to the S-NSSAI is increased if the UE reaches registration to the network slice according to NSAC, or whether the number of UEs registered to the S-NSSAI is decreased if the UE is deregistered from the S-NSSAI or fails to update the UE's registration to the S-NSSAI according to NSAC.

[0256] 3. The NSACF updates the current number of UEs registered for the S-NSSAI based on the information provided by the AMF in the update flag parameter, i.e., increases or decreases the number of UEs registered per network slice.

[0257] If the Update Flags parameter from the AMF indicates an increase, the following applies: If the UE ID is already in the list of UEs registered in the network slice, the UE is already counted as registered in the network slice, so do not increase the current number of UEs. The NSACF creates a new entry associated with this new update and also temporarily maintains the old entry associated with the previous update. When the NSACF receives a request with an update flag indicating a decrease, it removes the old entry.

[0258] NOTE 2: The use case of having two temporary entries in the NSACF for the same UE may occur during inter-AMF mobility, when there is no UE context transfer and the UE requests to register with an S-NSSAI according to an NSAC already used in the old AMF. The old entry in the NSACF is removed by the old AMF.

[0259] If the UE ID is not in the list of UE IDs to be registered in the network slice and the maximum number of UEs to be registered in the network slice has not yet been reached, the NSACF adds the UE ID to the list of UEs to be registered in the network slice and increases the current number of UEs to be registered in the network slice. If the UE ID is not in the list of UEs to be registered in that S-NSSAI and the maximum number of UEs for that S-NSSAI has already been reached, the NSACF returns a result parameter indicating that the maximum number of UEs to be registered in the network slice has been reached.

[0260] If the update flag parameter from the AMF indicates a decrease and if there is only one entry associated with the UE ID, the NSACF removes the UE ID from the list of UEs registered in the network slice for each of the S-NSSAIs indicated in the request from the AMF, and the NSACF also reduces the number of UEs per network slice maintained by the NSACF for each of the network slices. If there are two entries associated with the UE ID, the NSACF removes the old entry and maintains the new entry.

[0261] The NSACF takes into account the access type to scale the number of UEs per network slice, as described in clause 5.15.11.1 of TS 23.501 [2].

[0262] 4. The NSACF returns an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response in which the NSACF includes an S-NSSAI that already reaches the maximum number of UEs per network slice, along with a result parameter indicating that the maximum number of UEs registered to the network slice has been reached.

[0263] In the UE registration procedure, if only some of the S-NSSAIs have reached the maximum number of UEs per S-NSSAI or the AMF has not received an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response for a certain time, the AMF sends a registration acceptance message to the UE, in which the AMF includes in a rejected NSSAI list the rejected S-NSSAIs for which the NSACF has indicated that the maximum number of UEs per network slice has been reached or for which the AMF has not received an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response for a certain time for the S-NSSAI, and for each rejected S-NSSAI, the AMF includes a rejection cause set to "maximum number of UEs per network slice has been reached" and optionally a back-off timer.

[0264] If the NSACF returns that the maximum number of UEs per network slice has been reached for all requested S-NSSAIs provided in step 2, and if one or more subscribed S-NSSAIs are marked as default in the subscription data and do not follow the network slice admission control, the AMF may decide to include the default subscribed S-NSSAI in the allowed NSSAI. Otherwise, the AMF rejects the UE's request for registration. In the registration reject message, the AMF includes the rejected S-NSSAIs in the rejected NSSAI parameters, and for each rejected S-NSSAI, the AMF includes a rejection cause indicating that the maximum number of UEs per network slice has been reached and optionally a back-off timer.

[0265] NOTE 3: If a use case requires the UE to always remain reachable with at least one slice, it is recommended that at least one of the subscribed S-NSSAIs be marked as a default S-NSSAI that does not follow the network slice admission control, to ensure that the UE can access the service even if the maximum number of UEs per network slice is reached.

[0266] Editor's note: Whether and how to limit the signaling sent from the AMF to the NSACF when the maximum number of UEs is reached for a long period of time is FFS (required for further study).

[0267] Although the present disclosure has been shown and described in detail with reference to exemplary embodiments thereof, the present disclosure is not limited to such embodiments. It will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by this specification. For example, the above embodiments are not limited to 5GS, and the embodiments are also applicable to communication systems other than 5GS (e.g., 6G system, Beyond 5G system).

[0268] All or a part of the exemplary aspects of the above disclosure may be described as, but are not limited to, the following supplementary notes.

[0269] <First Addendum> Supplementary Note 1. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; and receiving a registration request message; the registration request message includes the S-NSSAI; and sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; starting a first timer when sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; sending a Non-Access Stratum (NAS) message if the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires; the NAS message includes a second timer value for stopping the registration procedure for the S-NSSAI; A method comprising:

[0270] Addition 2. Receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is successful; and sending another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to reduce the number of UEs for the S-NSSAI if the information indicates that the registration of the user equipment to the NSACF device is not successful; sending a message if the information indicates that the registration of the user equipment with the NSACF device is successful; the message includes an authorization NSSAI that includes the S-NSSAI; and 2. The method of claim 1, further comprising:

[0271] Appendix 3. The above Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAn d receiving an Update_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating a user equipment (UE); If the core network device does not have a UE context for the UE, sending another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to reduce the number of UEs for the S-NSSAI; and 2. The method of claim 1, further comprising:

[0272] Supplementary Note 4. The method of Supplementary Note 1, wherein the NAS message is sent when the first timer expires and the core network device receives a response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message.

[0273] Supplementary Note 5. The method of Supplementary Note 1, further comprising sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message when the first timer expires.

[0274] Supplementary Note 6. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; and receiving a registration request message; the registration request message includes the S-NSSAI; and sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; starting a timer when sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; sending a Non-Access Stratum (NAS) message if the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the timer expires; the NAS message includes an authorization NSSAI that includes the S-NSSAI; and receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating that registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is not successful; and sending a message if the UE has the authorized NSSAI, the message includes a rejection NSSAI that includes the S-NSSAI; and A method comprising:

[0275] Addition 7. A method of a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; and receiving a registration request message from a User Equipment (UE), the registration request message includes the S-NSSAI; and sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; starting a timer when sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; If the core network device determines that the UE does not support network slice admission control, sending a Non-Access Stratum (NAS) message, the NAS message includes an authorization NSSAI that includes the S-NSSAI; and receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating that registration of the UE to a Network Slice Admission Control Function (NSACF) device is not successful; and sending a message if the UE has the authorized NSSAI, the message includes a rejection NSSAI that includes the S-NSSAI; and A method comprising:

[0276] Supplementary Note 8. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is deactivated; and receiving a registration request message; the registration request message includes the S-NSSAI; and transmitting a first message, the first message includes an authorization NSSAI that includes the S-NSSAI; and sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is successful; and sending a second message if the information indicates that the registration of the UE to the NSACF device is not successful; the second message includes a rejection NSSAI that includes the S-NSSAI; and A method comprising:

[0277] Addition 9. The method further includes sending a third message if the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message; 9. The method of claim 8, wherein the third message includes a rejection NSSAI that includes the S-NSSAI.

[0278] Addendum 10. Starting a timer when sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message if the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the timer expires; 9. The method of claim 8, further comprising:

[0279] Addition 11. A method for a User Equipment (UE), the method comprising: sending a registration request message; The registration request message includes Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a Non-Access Stratum (NAS) message in the absence of a response regarding the registration of the UE to a Network Slice Admission Control Function (NSACF) device; the NAS message includes a timer value for stopping the registration procedure for the S-NSSAI; suspending the registration procedure until the timer expires; A method comprising:

[0280] Addition 12. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is deactivated; and receiving a registration request message; the registration request message includes the S-NSSAI; and Sending a message, the message includes an authorization NSSAI that includes the S-NSSAI; and sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; starting a first timer when sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; sending a Non-Access Stratum (NAS) message if the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires; The NAS message includes a value of a second timer for stopping a registration procedure for the S-NSSAI and a rejected NSSAI that includes the S-NSSAI; and A method comprising:

[0281] Addition 13. Receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating successful registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device; and sending another message when the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message is received, the other message includes the authorization NSSAI that includes the S-NSSAI; and 13. The method of claim 12, further comprising:

[0282] Supplementary Note 14. The method of Supplementary Note 12, wherein the NAS message is sent if the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires and there is no response after the core network device sends another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message.

[0283] Addition 15. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; and receiving a registration request message; the registration request message includes the S-NSSAI; and transmitting a first message, The first message includes information indicating that registration of a User Equipment (UE) for the S-NSSAI to a Network Slice Admission Control Function (NSACF) device is pending; and sending an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message, the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to increase the number of UEs for the S-NSSAI; receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether the registration is successful; and sending a second message if the information indicates that the registration is successful; the second message includes an authorization NSSAI that includes the S-NSSAI; and sending a third message if the information indicates that the registration was not successful; the third message includes a rejection NSSAI that includes the S-NSSAI and a timer value for stopping the registration procedure for the S-NSSAI; A method comprising:

[0284] Addition 16. A method for a core network device, the method comprising: receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that a Network Slice Admission Control Function (NSACF) device is overloaded; and receiving a registration request message; the registration request message includes the S-NSSAI; and Sending a message, The message includes information indicating that registration of the User Equipment (UE) for the S-NSSAI to the NSACF device is pending, and a timer value for stopping procedures related to the S-NSSAI; A method comprising:

[0285] Addition 17. A method of a core network device, the method comprising receiving a Protocol Data Unit (PDU) session establishment request message, The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); and sending an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message, The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to increase the number of PDU sessions for the S-NSSAI; and starting a first timer when sending the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message; sending a PDU session establishment rejection message when the core network device does not receive a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires; The PDU session establishment rejection message includes a second timer value for stopping the procedure of establishing a PDU session for the S-NSSAI; and A method comprising:

[0286] Supplementary Note 18. Receiving a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the number of PDU sessions for the S-NSSAI has been successfully increased; sending another Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message; The other Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to reduce the number of PDU sessions for the S-NSSAI; and 18. The method of claim 17, further comprising:

[0287] Supplementary Note 19. Receiving a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the number of PDU sessions for the S-NSSAI has been successfully increased; performing a network triggered service request procedure after receiving the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message; 18. The method of claim 17, further comprising:

[0288] Addition 20. A method for a core network device, the method comprising: receiving a Protocol Data Unit (PDU) session establishment request message, The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); and When the core network device recognizes that a Network Slice Admission Control Function (NSACF) device is overloaded, the core network device sends a PDU session establishment reject message, The PDU session establishment rejection message includes a second timer value for stopping the procedure of establishing a PDU session for the S-NSSAI; and A method comprising:

[0289] Addition 21. A method for a User Equipment (UE), the method comprising: Sending a Protocol Data Unit (PDU) session establishment request message, The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a PDU session establishment rejection message when there is no response regarding the registration of the PDU session to a Network Slice Admission Control Function (NSACF) device; The PDU session establishment rejection message includes a timer value for stopping the procedure of establishing a PDU session for the S-NSSAI; and Suspending the procedure until the timer expires; A method comprising:

[0290] Addition 22. A method for a User Equipment (UE), the method comprising: Sending a Protocol Data Unit (PDU) session establishment request message, The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a PDU session establishment reject message when a Network Slice Admission Control Function (NSACF) device is overloaded, The PDU session establishment rejection message includes a timer value for stopping the procedure of establishing a PDU session for the S-NSSAI; and Suspending the procedure until the timer expires; A method comprising:

[0291] Addition 23. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; means for starting a first timer when transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; A means for transmitting a Non-Access Stratum (NAS) message when the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires, the means comprising: The NAS message includes a second timer value for stopping a registration procedure for the S-NSSAI; A core network device comprising:

[0292] Addendum 24. A means for receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, comprising: The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is successful; and means for sending another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to reduce the number of UEs for the S-NSSAI if the information indicates that the registration of the user equipment to the NSACF device is not successful; means for sending a message if the information indicates that the registration of the user equipment with the NSACF device is successful, the message includes an authorization NSSAI that includes the S-NSSAI; 24. The core network device of claim 23, further comprising:

[0293] Addendum 25. A means for receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, comprising: The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating a user equipment (UE); means for sending another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to reduce the number of UEs for the S-NSSAI when the core network device does not have a UE context for the UE; 24. The core network device of claim 23, further comprising:

[0294] Addition 26. The core network device of Addition 23, wherein the NAS message is sent when the first timer expires and the core network device receives a response to the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message.

[0295] Addendum 27. The core network device of Addendum 23, further comprising means for sending the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message when the first timer expires.

[0296] Addition 28. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; means for starting a timer when transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; A means for transmitting a Non-Access Stratum (NAS) message when the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the timer expires, the means comprising: The NAS message includes an authorization NSSAI that includes the S-NSSAI; A means for receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating that registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is not successful; A means for sending a message when the UE has the authorized NSSAI, comprising: the message includes a rejection NSSAI that includes the S-NSSAI; A core network device comprising:

[0297] Addition 29. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; A means for receiving a registration request message from a User Equipment (UE), the registration request message includes the S-NSSAI; A means for sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; means for starting a timer when transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; A means for transmitting a Non-Access Stratum (NAS) message when the core network device determines that the UE does not support network slice admission control, comprising: The NAS message includes an authorization NSSAI that includes the S-NSSAI; A means for receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating that registration of the UE to a Network Slice Admission Control Function (NSACF) device is not successful; and A means for sending a message when the UE has the authorized NSSAI, comprising: the message includes a rejection NSSAI that includes the S-NSSAI; A core network device comprising:

[0298] Addition 30. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is deactivated; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for transmitting a first message, comprising: the first message includes an authorization NSSAI that includes the S-NSSAI; A means for sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; A means for receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device is successful; and means for transmitting a second message if the information indicates that the registration of the UE with the NSACF device is not successful, the second message includes a rejection NSSAI that includes the S-NSSAI; A core network device comprising:

[0299] Addition 31. The method according to claim 1, further comprising the step of: sending a third message when the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message; The core network device of claim 30, wherein the third message includes a rejection NSSAI that includes the S-NSSAI.

[0300] Addition 32. Means for starting a timer when transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; means for transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message if the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the timer expires; 31. The core network device of claim 30, further comprising:

[0301] Addition 33. A User Equipment (UE), comprising: A means for transmitting a registration request message, The registration request message includes Single Network Slice Selection Assistance Information (S-NSSAI); A means for receiving a Non-Access Stratum (NAS) message in the absence of a response regarding the registration of the UE to a Network Slice Admission Control Function (NSACF) device, the means comprising: The NAS message includes a timer value for stopping the registration procedure for the S-NSSAI. means for suspending the registration procedure until the timer expires; A UE equipped with the above.

[0302] Addition 34. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is deactivated; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for sending a message, comprising: the message includes an authorization NSSAI that includes the S-NSSAI; A means for sending a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; means for starting a first timer when transmitting the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message; A means for transmitting a Non-Access Stratum (NAS) message when the core network device does not receive a Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires, the means comprising: The NAS message includes a value of a second timer for stopping a registration procedure for the S-NSSAI and a rejected NSSAI that includes the S-NSSAI; A core network device comprising:

[0303] Addendum 35. A means for receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, comprising: The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating successful registration of a User Equipment (UE) to a Network Slice Admission Control Function (NSACF) device; A means for sending another message when receiving the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, comprising: The other message includes the authorization NSSAI, which includes the S-NSSAI; and 35. The core network device of claim 34, further comprising:

[0304] Addendum 36. A core network device as described in Addendum 34, wherein the NAS message is sent if the core network device does not receive the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires and there is no response after the core network device sends another Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message.

[0305] Addition 37. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that an Early Admission Control (EAC) mode is activated; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for transmitting a first message, comprising: The first message includes information indicating that registration of a User Equipment (UE) for the S-NSSAI to a Network Slice Admission Control Function (NSACF) device is pending; A means for transmitting an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message, the Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to increase the number of UEs for the S-NSSAI; A means for receiving an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message, The Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message includes information indicating whether the registration is successful; means for sending a second message if the information indicates that the registration is successful, the second message includes an authorization NSSAI that includes the S-NSSAI; means for sending a third message if the information indicates that the registration was not successful, The third message includes a rejection NSSAI including the S-NSSAI and a timer value for stopping the registration procedure for the S-NSSAI; A core network device comprising:

[0306] Addition 38. A core network device, comprising: A means for receiving an Nnsacf_NumberOfUEsPerSliceEACNotify message, The Nnsacf_NumberOfUEsPerSliceEACNotify message includes Single Network Slice Selection Assistance Information (S-NSSAI) and information indicating that a Network Slice Admission Control Function (NSACF) device is overloaded; A means for receiving a registration request message, the registration request message includes the S-NSSAI; A means for sending a message, comprising: The message includes information indicating that registration of a User Equipment (UE) for the S-NSSAI to the NSACF device is pending, and a timer value for stopping procedures related to the S-NSSAI; A core network device comprising:

[0307] Addition 39. A core network device, comprising: means for receiving a Protocol Data Unit (PDU) session establishment request message, the means comprising: The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); A means for transmitting an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message, The Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to increase the number of PDU sessions for the S-NSSAI; means for starting a first timer when transmitting the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message; A means for transmitting a PDU session establishment rejection message when the core network device does not receive a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message until the first timer expires, comprising: The PDU session establishment rejection message includes a value of a second timer for stopping a procedure for establishing a PDU session for the S-NSSAI; A core network device comprising:

[0308] Supplementary Note 40. Means for receiving a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the number of PDU sessions for the S-NSSAI has been successfully increased; a means for transmitting another Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message, The another Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Request message includes the S-NSSAI and a request to reduce the number of PDU sessions for the S-NSSAI; 40. The core network device of claim 39, further comprising:

[0309] Addition 41. Means for receiving a Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message indicating that the number of PDU sessions for the S-NSSAI has been successfully increased; means for performing a network-triggered service request procedure after receiving the Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate_Response message; 40. The core network device of claim 39, further comprising:

[0310] Addition 42. A core network device, comprising: A means for receiving a Protocol Data Unit (PDU) session establishment request message, comprising: The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); A means for transmitting a PDU session establishment rejection message when the core network device recognizes that a Network Slice Admission Control Function (NSACF) device is overloaded, comprising: The PDU session establishment rejection message includes a value of a second timer for stopping a procedure for establishing a PDU session for the S-NSSAI; A core network device comprising:

[0311] Addition 43. A User Equipment (UE), comprising: A means for transmitting a Protocol Data Unit (PDU) session establishment request message, comprising: The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); A means for receiving a PDU session establishment rejection message when there is no response regarding the registration of the PDU session to a Network Slice Admission Control Function (NSACF) device, comprising: The PDU session establishment rejection message includes a timer value for stopping a procedure for establishing a PDU session for the S-NSSAI; means for suspending said procedure until said timer expires; A UE equipped with the above.

[0312] Addition 44. A User Equipment (UE), comprising: A means for transmitting a Protocol Data Unit (PDU) session establishment request message, comprising: The PDU session establishment request message includes Single Network Slice Selection Assistance Information (S-NSSAI); A means for receiving a PDU session establishment reject message when a Network Slice Admission Control Function (NSACF) device is overloaded, the means comprising: The PDU session establishment rejection message includes a timer value for stopping a procedure for establishing a PDU session for the S-NSSAI; means for suspending said procedure until said timer expires; A UE equipped with the above.

[0313] <Second Note> Supplementary Note 1. An Access and Mobility Management Function (AMF) device in communication with a User Equipment (UE) and a Network Slice Admission Control Function (NSACF) device, the AMF device comprising: A receiver; A transmitter; wherein the receiver is configured to receive from the UE a registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI); The transmitter is configured to send a Non-Access Stratum (NAS) message to the UE, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first feature; The transmitter is configured to send the NAS message including a rejection NSSAI including a second cause value to the UE when the UE does not support the first function, an AMF device.

[0314] Supplementary Note 2. The NAS message includes a CONFIGURATION UPDATE COMMAND message if the UE has at least one authorized NSSAI; The AMF device of Supplementary Note 1, wherein the NAS message includes a DEREGISTRATION REQUEST message when the UE has no authorized NSSAI.

[0315] Supplementary Note 3. The first cause value indicates that a Single-NSSAI (S-NSSAI) is not available due to a maximum number of the UEs being reached; The AMF device of claim 1 or 2, wherein the second cause value indicates that the S-NSSAI is not allowed in the tracking area.

[0316] Supplementary Note 4. An AMF device as described in any one of Supplementary Notes 1 to 3, wherein the first function indicates that the UE supports NSACF.

[0317] Supplementary Note 5. The AMF device sends a request to the NSACF device; An AMF device described in any one of Supplementary Notes 1 to 4, wherein the AMF processes the NAS message while the AMF device is waiting for a response from the NSACF device.

[0318] Supplementary Note 6. The AMF device sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF device, the NSACF device including at least one of a UE ID, an access type, an S-NSSAI, and an update flag; An AMF device described in any one of Supplementary Notes 1 to 5, wherein the AMF device receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF device indicating whether the maximum number of UEs registered in a network slice has been reached or whether the maximum number of UEs registered in a network slice has not been reached.

[0319] Supplementary Note 7. A User equipment (UE) in communication with an Access and Mobility Management Function (AMF) device in communication with a Network Slice Admission Control Function (NSACF) device, the UE comprising: A receiver; A transmitter; The transmitter is configured to send a registration request message to the AMF device, the registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI); The receiver is configured to receive, when the UE supports the first function, a Non-Access Stratum (NAS) message from the AMF device, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value; The receiver is configured to receive the NAS message including a rejection NSSAI including a second cause value from the AMF device when the UE does not support the first function.

[0320] Supplementary Note 8. The NAS message includes a CONFIGURATION UPDATE COMMAND message if the UE has at least one authorized NSSAI; 8. The UE of claim 7, wherein the NAS message includes a DEREGISTRATION REQUEST message if the UE does not have any authorized NSSAI.

[0321] Addendum 9. The first cause value indicates that a Single-NSSAI (S-NSSAI) is not available because a maximum number of UEs has been reached; 9. The UE of claim 7 or 8, wherein the second cause value indicates that the S-NSSAI is not allowed in a tracking area.

[0322] Supplementary Note 10. The UE of any one of Supplementary Notes 7 to 9, wherein the first capability indicates that the UE supports NSACF.

[0323] Supplementary Note 11. When the UE receives the rejection NSSAI including the first cause value and the back-off timer value, The UE according to any one of Supplementary Notes 7 to 10, wherein the UE updates the NSSAI included in the UE based on the rejection NSSAI including the first cause and the back-off timer value.

[0324] Supplementary Note 12. When the UE receives the rejection NSSAI including the second cause value, The UE according to any one of Supplementary Notes 7 to 11, wherein the UE updates the NSSAI included in the UE based on the rejection NSSAI including the second cause.

[0325] Supplementary Note 13. A method of an Access and Mobility Management Function (AMF) device communicating with a User equipment (UE) and a Network Slice Admission Control Function (NSACF) device, the method comprising: receiving a registration request message from the UE, the registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI); sending a Non-Access Stratum (NAS) message to the UE, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value, if the UE supports the first feature; sending the NAS message to the UE, the NAS message including a rejection NSSAI including a second cause value if the UE does not support the first feature; A method comprising:

[0326] Supplementary Note 14. The NAS message includes a CONFIGURATION UPDATE COMMAND message if the UE has at least one authorized NSSAI; The method of claim 13, wherein the NAS message includes a DEREGISTRATION REQUEST message if the UE does not have any authorized NSSAI.

[0327] Addendum 15. The first cause value indicates that a Single-NSSAI (S-NSSAI) is not available because a maximum number of UEs has been reached; 15. The method of claim 13 or 14, wherein the second cause value indicates that the S-NSSAI is not allowed in a tracking area.

[0328] Supplementary Note 16. The method of any one of Supplementary Notes 13 to 15, wherein the first capability indicates that the UE supports NSACF.

[0329] Addition 17. The AMF device sends a request to the NSACF device; A method according to any one of Supplementary Notes 13 to 16, wherein the AMF device processes the NAS message while the AMF device is waiting for a response from the NSACF device.

[0330] Supplementary Note 18. The AMF device sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request message to the NSACF device, the NSACF device including at least one of a UE ID, an access type, an S-NSSAI, and an update flag; A method according to any one of Supplementary Notes 13 to 17, wherein the AMF device receives an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response message from the NSACF device indicating whether the maximum number of UEs registered in a network slice has been reached or whether the maximum number of UEs registered in a network slice has not been reached.

[0331] Addendum 19. A method of a User equipment (UE) communicating with an Access and Mobility Management Function (AMF) device communicating with a Network Slice Admission Control Function (NSACF) device, comprising: method teeth, Sending a registration request message to the AMF device, the registration request message including first information indicating whether the UE supports a first capability and a requested Network Slice Selection Assistance Information (NSSAI); receiving a Non-Access Stratum (NAS) message from the AMF device, the NAS message including a rejection NSSAI including a first cause value and a back-off timer value when the UE supports the first feature; receiving the NAS message from the AMF device, the NAS message including a rejection NSSAI including a second cause value when the UE does not support the first feature; A method comprising:

[0332] Supplementary Note 20. The NAS message includes a CONFIGURATION UPDATE COMMAND message if the UE has at least one authorized NSSAI; 20. The method of claim 19, wherein the NAS message includes a DEREGISTRATION REQUEST message if the UE does not have any authorized NSSAI.

[0333] Addendum 21. The first cause value indicates that a Single-NSSAI (S-NSSAI) is not available due to a maximum number of the UEs being reached; 21. The method of claim 19 or 20, wherein the second cause value indicates that the S-NSSAI is not allowed in a tracking area.

[0334] Supplementary Note 22. The method of any one of Supplementary Notes 19 to 21, wherein the first capability indicates that the UE supports NSACF.

[0335] Supplementary Note 23. When the UE receives the rejection NSSAI including the first cause value and a back-off timer value, The UE, the first cause value and the backoff timer value 22. The method of claim 19, further comprising updating the NSSAI included in the UE based on the rejected NSSAI including:

[0336] Although the present invention has been described above with reference to the embodiments (and examples), the present invention is not limited to the above-mentioned embodiments (and examples). Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0337] This application claims priority to Indian Provisional Patent Application No. 202111032979, filed on July 22, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0338] 1. Telecommunications Systems 3. UE 5 (R)AN Nodes 7 Core Network 20 Data Network 31 Transceiver Circuit 32 Antenna 33 Controller 34 User Interface 35 USIM 36 Memory 51 Transceiver Circuit 52 Antenna 53 Network Interface 54 Controller 55 Memory 60RU 61DU 62 CU 70 AMF 71 SMF 72 UPF 73 PCF 74 NEF 75 UDM 76 NWDAF 77 NSACF 361 Operating Systems 362 Communication Control Module 551 Operating Systems 552 Communication Control Module 601 Transceiver Circuit 602 Antenna 603 Network Interface 604 Controller 605 Memory 611 Transceiver Circuit 612 Network Interface 613 Controller 614 Memory 621 Transceiver Circuit 622 Network Interface 623 Controller 624 Memory 701 Transceiver Circuit 702 Network Interface 703 Controller 704 Memory 711 Transceiver Circuit 712 Network Interface 713 Controller 714 Memory 721 Transceiver Circuit 722 Network Interface 723 Controller 724 Memory 731 Transceiver Circuits 732 Network Interface 733 Controller 734 Memory 741 Transceiver Circuit 742 Network Interface 743 Controller 744 Memory 751 Transceiver Circuit 752 Network Interface 753 Controller 754 Memory 761 Transceiver Circuit 762 Network Interface 763 Controller 764 Memory 771 Transceiver Circuit 772 Network Interface 773 Controller 774 Memory 3621 Transceiver Control Module 5521 Transceiver Control Module 6051 Operating System 6052 Communication Control Module 6141 Operating Systems 6142 Communication Control Module 6241 Operating Systems 6242 Communication Control Module 7041 Operating Systems 7042 Communication Control Module 7141 Operating Systems 7142 Communication Control Module 7241 Operating Systems 7242 Communication Control Module 7341 Operating Systems 7342 Communication Control Module 7441 Operating Systems 7442 Communication Control Module 7541 Operating Systems 7542 Communication Control Module 7641 Operating Systems 7642 Communication Control Module 7741 Operating Systems 7742 Communication Control Module 60521 Transceiver Control Module 61421 Transceiver Control Module 62421 Transceiver Control Module 70421 Transceiver Control Module 71421 Transceiver Control Module 72421 Transceiver Control Module 73421 Transceiver Control Module 74421 Transceiver Control Module 75421 Transceiver Control Module 76421 Transceiver Control Module 77421 Transceiver Control Module< / nsacf> < / nedaf> < / udm> < / nef> < / pcf> < / upf> < / smf> < / amf>

Claims

1. A method for an Access and Mobility Management Function (AMF), comprising: receiving a registration request message from a user equipment (UE); The registration request message includes a requested Network Slice Selection Assistance Information (requested NSSAI), The request NSSAI includes S-NSSAI (Single Network Slice Selection Assistance Information), If an Early Admission Control (EAC) mode is deactivated for the S-NSSAI, sending an allowed NSSAI to the UE, the allowed NSSAI including the S-NSSAI; While the AMF is waiting for a response from a Network Slice Admission Control Function (NSACF) for the S-NSSAI, it processes a first Non-Access Stratum (NAS) message for the S-NSSAI; After the AMF waits for the response from the NSACF regarding the S-NSSAI, sending a deregistration request message to the UE; The deregistration request message includes a rejected NSSAI, The Reject NSSAI includes the S-NSSAI. AMF method.

2. Sending a registration request message to the AMF; The registration request message includes a requested NSSAI, The request NSSAI includes an S-NSSAI, If an EAC mode is deactivated for the S-NSSAI, receiving an allowed NSSAI from the AMF, the allowed NSSAI including the S-NSSAI; receiving a deregistration request message after waiting for a response from an NSACF for the S-NSSAI; The deregistration request message includes a rejected NSSAI, The Reject NSSAI includes the S-NSSAI. A method for a UE.

3. A means for receiving a registration request message from a UE, the registration request message including a request NSSAI including an S-NSSAI; means for sending an allowed NSSAI including the S-NSSAI to the UE if an EAC mode is deactivated for the S-NSSAI; A means for processing a first NAS message related to the S-NSSAI while the AMF is waiting for a response related to the S-NSSAI from an NSACF; means for sending a deregistration request message to the UE, the deregistration request message including a rejected NSSAI including the S-NSSAI, after the AMF waits for the response from the NSACF regarding the S-NSSAI; AMF equipped with.

4. A means for sending a registration request message to an AMF, the registration request message including a requested NSSAI including an S-NSSAI; means for receiving an allowed NSSAI from the AMF, the allowed NSSAI including the S-NSSAI, when an EAC mode is deactivated for the S-NSSAI; means for receiving a deregistration request message including a rejected NSSAI that includes the S-NSSAI after a response from an NSACF regarding the S-NSSAI is awaited; A UE comprising:

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