SMF Methods and SMF

Abstract

One prominent issue with the Network Slice Admission Control (NSACF) of the 3GPP Rel-17 agreement is whether and how to enhance the system to ensure network control behavior of network slice usage, including UE registration and PDU session establishment. For example, the NSACF needs a mechanism to resolve problematic situations where the network slice cannot serve actual operation to at least one of the UE and PDU session when NSAC is in progress. For example, the NSACF needs a mechanism to resolve problematic situations when the network slice is used by the UE or PDU session. [Solution] The method of the communications device includes transmitting a first message. The first message includes a Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a second message if the S-NSSAI has not been used for a period of time. The second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time is associated with the S-NSSAI. The method includes transmitting a third message to remove the S-NSSAI from an allowed Network Slice Selection Assistance Information (NSSAI). The third message includes the S-NSSAI and the rejection cause.

Description

[Technical Field]

[0001] The present disclosure relates to a method of a communication device, a method of a User Equipment (UE), a communication device, a UE, a method of a first core network device, a method of a third core network device, and a method of a first network slice control function node. [Background technology]

[0002] SA2#148E approved a new Rel-18 study (eNS_Ph3) on network slicing in 3GPP TS 21.21.22. When a UE registers, it generates a Requested-NSSAI based on the Configured-NSSAI and the Allowed-NSSAI, and may also take into account URSP rules. The UE may register an S-NSSAI that is not planned to be used immediately (e.g., no ongoing application is planned to establish a PDU session in the network slice) and, possibly, is not planned to be used while registered in this Registration Area (RA). Similarly, after an application has terminated, the PDU session may not be used by any other application in the UE (no ongoing application traffic is carried over the PDU session). This may be perceived as a problem by the operator's customers; for example, if Network Slice Admission Control (NSAC) is deployed, this may prevent additional UEs from registering the S-NSSAI and requesting the S-NSSAI for PDU sessions. Another issue is that operators may have Service Level Agreements (SLAs) with their customers related to the availability of their services. If a network slice is congested and other network slices can better serve the SLA, the network may determine that the UE traffic flow is better served by a different network slice. [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] S2-2109356 Study on Enhancement of Network Slicing Phase 3 https: / / www.3gpp.org / ftp / tsg_sa / WG2_Arch / TSGS2_148E_Electronic_2021-11 / Docs / S2-2109356.zip [Non-patent document 3] 3GPP TS 23.502: "Procedures for the 5G System (5GS)". V17.2.0 (2021-09) Summary of the Invention [Problem to be solved by the invention]

[0004] One prominent issue with the Network Slice Admission Control (NSACF) in the 3GPP Rel-17 agreement is whether and how to enhance the system to ensure network control behavior for network slice usage, including UE registration and PDU session establishment. For example, the NSACF needs a mechanism to resolve problematic situations in which the network slice cannot provide actual service to at least one of the UE and PDU session when performing NSAC. For example, the NSACF needs a mechanism to resolve problematic situations when the network slice is used by the UE or PDU session. [Means for solving the problem]

[0005] In an aspect of the disclosure, a method of a communications device includes transmitting a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a second message if the S-NSSAI has not been used for a period of time. The second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time is associated with the S-NSSAI. The method includes transmitting a third message to remove the S-NSSAI from an allowed Network Slice Selection Assistance Information (NSSAI). The third message includes the S-NSSAI and the rejection cause.

[0006] In an aspect of the disclosure, a method of a communications device includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes performing Network Slice Admission Control (NSAC) if the timer expires. The method includes, after performing NSAC, transmitting a second message. The second message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0007] In an aspect of the present disclosure, a method in a User Equipment (UE) includes registering for a Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a message. The message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time. The period of time is associated with the S-NSSAI. The method includes, after receiving the message, removing the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI).

[0008] In an aspect of the disclosure, a method of a communications device includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes transmitting a second message for Network Slice Admission Control (NSAC) and a third message if the timer expires. The second message includes the S-NSSAI. The third message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0009] In an aspect of the disclosure, a method of a communications apparatus includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes, after starting the timer, receiving a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI. The method includes, after receiving the second message, stopping the timer. The method includes, after stopping the timer, receiving a third message related to release of the PDU session. The method includes, after receiving the third message, starting the timer. The method includes, if the timer expires, transmitting a fourth message. The fourth message is for removing the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI.

[0010] In an aspect of the present disclosure, a method of a communications device includes transmitting a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a second message. The second message includes an identification of a Protocol Data Unit (PDU) session. The method includes, after receiving the second message, starting a timer. The method includes, if there is no user plane activity for the PDU session until the timer expires, transmitting a third message. The third message indicates there is no user plane activity for the PDU session. The method includes, after transmitting the third message, receiving a fourth message. The method includes, after receiving the fourth message, performing a procedure for releasing the PDU session.

[0011] In an aspect of the present disclosure, a method in a communications device includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes transmitting a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The method includes, after transmitting the second message, receiving a third message. The third message indicates no user plane operation for the PDU session. The method includes, after receiving the third message, transmitting a fourth message. The fourth message is for performing a procedure to release the PDU session.

[0012] In an aspect of the disclosure, a communications apparatus includes means for transmitting a first message. The first message includes a Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for receiving a second message if the S-NSSAI has not been used for a period of time. The second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time is associated with the S-NSSAI. The apparatus includes means for transmitting a third message to remove the S-NSSAI from an allowed Network Slice Selection Assistance Information (NSSAI). The third message includes the S-NSSAI and the rejection cause.

[0013] In an aspect of the present disclosure, a communications apparatus includes means for receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for starting a timer for the S-NSSAI after receiving the first message. The timer is set to a value associated with the S-NSSAI. The apparatus includes means for performing Network Slice Admission Control (NSAC) if the timer expires. The apparatus includes means for transmitting a second message after performing NSAC. The second message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0014] In an aspect of the present disclosure, a User Equipment (UE) includes means for registering for a Single Network Slice Selection Assistance Information (S-NSSAI). The UE includes means for receiving a message. The message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time. The period of time is associated with the S-NSSAI. The UE includes means for removing the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI) after receiving the message.

[0015] In an aspect of the present disclosure, a communications apparatus includes means for receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for starting a timer for the S-NSSAI after receiving the first message. The timer is set to a value associated with the S-NSSAI. The apparatus includes means for transmitting a second message for Network Slice Admission Control (NSAC) and a third message if the timer expires. The second message includes the S-NSSAI. The third message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0016] In an aspect of the present disclosure, a communications apparatus includes means for receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The apparatus includes means for, after starting the timer, receiving a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI. The apparatus includes means for, after receiving the second message, stopping the timer. The apparatus includes means for, after stopping the timer, receiving a third message related to release of the PDU session. The apparatus includes means for, after receiving the third message, starting the timer. The apparatus includes means for transmitting a fourth message if the timer expires. The fourth message is for removing the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI.

[0017] In an aspect of the present disclosure, a communications apparatus includes means for transmitting a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for receiving a second message. The second message includes an identification of a Protocol Data Unit (PDU) session. The apparatus includes means for starting a timer after receiving the second message. The apparatus includes means for transmitting a third message if there is no user plane activity for the PDU session until the timer expires. The third message indicates there is no user plane activity for the PDU session. The apparatus includes means for receiving a fourth message after transmitting the third message. The apparatus includes means for performing a procedure to release the PDU session after receiving the fourth message.

[0018] In an aspect of the present disclosure, a communications apparatus includes means for receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The apparatus includes means for transmitting a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The apparatus includes means for receiving a third message after transmitting the second message. The third message indicates no user plane operation for the PDU session. The apparatus includes means for transmitting a fourth message after receiving the third message. The fourth message is for performing a procedure to release the PDU session.

[0019] In an aspect of the present disclosure, a method in a first core network device includes receiving a fourth message related to management of a network slice from a second core network device. The method includes, after receiving the fourth message, starting a timer for the network slice. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a fifth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use.

[0020] In an aspect of the present disclosure, a method in a first core network device includes receiving a fourth message related to management of a network slice from a second core network device. The method includes starting a timer for the network slice after receiving the fourth message. The method includes detecting an operation related to the network slice. The method includes stopping the timer after detecting the operation.

[0021] In an aspect of the present disclosure, a method in a third core network device includes receiving a sixth message related to management of a network slice from a first core network device. The method includes analyzing data related to the network slice based on information received from the other core network device and starting a timer for the network slice after receiving the sixth message. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a seventh message to the first core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use, wherein the first core network device manages network slice admission control.

[0022] In an aspect of the present disclosure, a method of a third core network device includes receiving a sixth message related to management of a network slice from a first core network device. The method includes analyzing data related to the network slice based on information received from the other core network device. The method includes starting a timer for the network slice after receiving the sixth message. The method includes detecting an operation related to the network slice. The method includes stopping the timer after detecting the operation, wherein the first core network device manages network slice admission control.

[0023] In an aspect of the present disclosure, a method in a first network slice control function node includes receiving an eighth message related to management of the network slice from a second core network device. The method includes, after receiving the eighth message, starting a timer for the network slice. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a ninth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use.

[0024] In an aspect of the present disclosure, a method in a first network slice control function node includes receiving a tenth message related to management of the network slice from a second core network device. The method includes starting a timer for the network slice after receiving the tenth message. The method includes receiving an eleventh message from a second network slice control function node detecting an operation related to the network slice. The method includes stopping the timer after receiving the eleventh message.

[0025] In an aspect of the present disclosure, a method in a third core network device includes transmitting first information related to management of a network slice to a first core network device to initiate control of the number of sessions based on a timer. The method includes receiving second information from the first core network device indicating that the control will be initiated. The method includes monitoring user plane activity related to the sessions after receiving the second information. The method includes transmitting third information to the first core network device indicating that no user plane activity is detected based on the monitoring. The method includes receiving fourth information from the first core network device indicating at least one of the timer expiring or the session not being active within a period specified by the timer.

[0026] In an aspect of the present disclosure, a method in a first core network device includes receiving, from a third core network device, fifth information related to management of a network slice. The method includes starting a timer for the network slice after receiving the fifth information. The method includes sending sixth information to the third core network device indicating that management will be initiated to start monitoring of user plane operations related to the session. The method includes receiving seventh information from the third core network device indicating that no user plane operations are detected based on the monitoring. The method includes sending eighth information to the third core network device indicating at least one of expiration of the timer or inactivity of the session within a period specified by the timer. [Brief explanation of the drawings]

[0027] [Figure 1] Figure 1 is a signaling diagram relating to a first example of the first aspect (network slice usage control for UE registration by NSACF). [Figure 2] Figure 2 is a signaling diagram relating to a second example of the first aspect (network slice usage control for UE registration by NWDAF). [Figure 3]Figure 3 is a signaling diagram relating to a third example of the first aspect (network slice usage control for UE registration by two NSACFs). [Figure 4] Figure 4 is a signaling diagram relating to a fourth example of the first aspect (network slice usage control of a PDU session by an NSACF). [Figure 5] FIG. 5 is a diagram showing an outline of the system. [Figure 6] FIG. 6 is a block diagram illustrating a user equipment (UE). [Figure 7] FIG. 7 is a block diagram illustrating an (R)AN node. [Figure 8] FIG. 8 is a diagram illustrating a system overview of an (R)AN node based on the O-RAN architecture. [Figure 9] FIG. 9 is a block diagram showing a radio unit (RU). [Figure 10] FIG. 10 is a block diagram showing a distributed unit (DU). [Figure 11] FIG. 11 is a block diagram showing a centralized unit (CU). [Figure 12] FIG. 12 is a block diagram illustrating the Access and Mobility Management Function (AMF). [Figure 13] FIG. 13 is a block diagram illustrating the User Plane Function (UPF). [Figure 14] FIG. 14 is a block diagram illustrating a Policy Control Function (PCF). [Figure 15] FIG. 15 is a block diagram illustrating the Authentication Server Function (AUSF). [Figure 16]FIG. 16 is a block diagram illustrating Unified Data Management (UDM). [Figure 17] FIG. 17 is a block diagram illustrating the Network Data Analytics Function (NWDAF). [Figure 18] FIG. 18 is a block diagram illustrating a Network Slice Admission Control Function (NSACF). [Figure 19] Figure 19 shows the procedure for checking and updating the availability of the number of UEs per network slice. [Figure 20] Figure 20 shows the procedure for checking and updating the availability of the number of PDU sessions per network slice. DETAILED DESCRIPTION OF THE INVENTION

[0028] <abbreviation> For purposes of this specification, the abbreviations given in Non-Patent Document 1 and the following apply: Abbreviations defined in this specification take precedence over the definition of the same abbreviation in Non-Patent Document 1 if the same abbreviation appears in that document.

[0029] 4G-GUTI 4G Globally Unique Temporary UE Identity 5GC 5G Core Network 5GLAN 5G Local Area Network 5GS 5G System 5G-AN 5G Access Network 5G-AN PDB 5G Access Network Packet Delay Budget 5G-EIR 5G-Equipment Identity Register 5G-GUTI 5G Globally Unique Temporary Identifier 5G-BRG 5G Broadband Residential Gateway 5G-CRG 5G Cable Residential Gateway 5G GM 5G Grand Master 5G-RG 5G Residential Gateway 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier 5G VN 5G Virtual Network 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AMF-G Geographically selected Access and Mobility Management Function AMF-NG Non-Geographically selected Access and Mobility Management Function AS Access Stratum ATSSS Access Traffic Steering, Switching, Splitting ATSSS-LL ATSSS Low-Layer AUSF Authentication Server Function AUTN Authentication token BMCA Best Master Clock Algorithm BSF Binding Support Function CAG Closed Access Group CAPIF Common API Framework for 3GPP northbound APIs CHF Charging Function CN PDB Core Network Packet Delay Budget CP Control Plane DAPS Dual Active Protocol Stacks DL Downlink DN Data Network DNAI DN Access Identifier DNN Data Network Name DRX Discontinuous Reception DS-TT Device-side TSN translator ePDG evolved Packet Data Gateway EBI EPS Bearer Identity EPS Evolved Packet System EUI Extended Unique Identifier FAR Forwarding Action Rule FN-BRG Fixed Network Broadband RG FN-CRG Fixed Network Cable RG FN-RG Fixed Network RG FQDN Fully Qualified Domain Name GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier GUTI Globally Unique Temporary UE Identity HR Home Routed (roaming) IAB Integrated access and backhaul IMEI / TAC IMEI Type Allocation Code IPUPS Inter PLMN UP Security I-SMF Intermediate SMF I-UPF Intermediate UPF LADN Local Area Data Network LBO Local Break Out (roaming) LMF Location Management Function LoA Level of Automation LPP LTE Positioning Protocol LRF Location Retrieval Function MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MITM Man In the Middle MNC Mobile Network Code MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol N3IWF Non-3GPP InterWorking Function N3GPP Non-3GPP access N5CW Non-5G-Capable over WLAN NAI Network Access Identifier NAS Non-Access-Stratum NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NID Network identifier NPN Non-Public Network NR New Radio NRF Network Repository Function NSAC Network Slice Admission Control NSACF Network Slice Admission Control Function NSI ID Network Slice Instance Identifier NSSAA Network Slice-Specific Authentication and Authorization NSSAAF Network Slice-Specific Authentication and Authorization Function NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy NSSRG Network Slice Simultaneous Registration Group NW-TT Network-side TSN translator NWDAF Network Data Analytics Function PCF Policy Control Function PDB Packet Delay Budget PDR Packet Detection Rule PDU Protocol Data Unit PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public Land Mobile Network PNI-NPN Public Network Integrated Non-Public Network PPD Paging Policy Differentiation PPF Paging Proceed Flag PPI Paging Policy Indicator PSA PDU Session Anchor PTP Precision Time Protocol QFI QoS Flow Identifier QoE Quality of Experience RACS Radio Capabilities Signalling optimisation (R)AN (Radio) Access Network RG Residential Gateway RIM Remote Interference Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RSN Redundancy Sequence Number SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SMF Session Management Function SMSF Short Message Service Function SN Sequence Number SN name Serving Network Name. SNPN Stand-alone Non-Public Network S-NSSAI Single Network Slice Selection Assistance Information SSC Session and Service Continuity SSCMSP Session and Service Continuity Mode Selection Policy SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier SV Software Version TMSI Temporary Mobile Subscriber Identity TNAN Trusted Non-3GPP Access Network TNAP Trusted Non-3GPP Access Point TNGF Trusted Non-3GPP Gateway Function TNL Transport Network Layer TNLA Transport Network Layer Association TSC Time Sensitive Communication TSCAI TSC Assistance Information TSN Time Sensitive Networking TSN GM TSN Grand Master TSP Traffic Steering Policy TT TSN Translator TWIF Trusted WLAN Interworking Function UCMF UE radio Capability Management Function UDM Unified Data Management UDR Unified Data Repository UDSF Unstructured Data Storage Function UL Uplink UL CL Uplink Classifier UPF User Plane Function URLLC Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy VID VLAN Identifier VLAN Virtual Local Area Network VPLMN Visited PLMN 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

[0030] <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 any.

[0031] <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. Furthermore, 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 relevant to understanding aspects of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.

[0032] To promote an understanding of the principles of the present disclosure, reference will now be made to embodiments illustrated in the drawings and specific language will be used to describe those principles. It will nevertheless be understood that no limitation on the scope of the present disclosure is intended thereby. Such alterations and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as would normally occur to one skilled in the art, are to be construed as being within the scope of the present disclosure.

[0033] 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 not only includes those steps, but may also include other steps not expressly listed or inherent in such process or method. Similarly, the reference to one or more devices, entities, subsystems, elements, structures, or components preceded by "comprises" 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.

[0034] 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.

[0035] In the following specification and claims, reference will be made to a number of terms that shall be defined to have the following meanings: The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0036] As used herein, information refers to data and knowledge, as data is meaningful information and represents values ​​attributed to parameters. Furthermore, knowledge refers to an understanding of an abstract or concrete concept. It should be noted that this exemplary system is simplified to facilitate explanation 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 as being within the scope of the present disclosure.

[0037] Each aspect and the elements included in each aspect described below can be implemented independently or in combination with each other. The aspects include different novel features. As such, the aspects contribute to achieving different objectives or solving different problems and achieving different advantages.

[0038] An exemplary object of the present disclosure is to provide a method and apparatus that can solve the above problems.

[0039] A method for a communications device according to an exemplary aspect of the present disclosure includes transmitting a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a second message when the S-NSSAI has not been used for a period of time. The second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time is associated with the S-NSSAI. The method includes transmitting a third message to remove the S-NSSAI from an allowed Network Slice Selection Assistance Information (NSSAI). The third message includes the S-NSSAI and the rejection cause.

[0040] A method of a communications device according to an example aspect of the present disclosure includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes performing Network Slice Admission Control (NSAC) if the timer expires. The method includes, after performing NSAC, transmitting a second message. The second message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0041] A method in a User Equipment (UE) according to an example aspect of the present disclosure includes registering for a Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a message. The message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time. The period of time is associated with the S-NSSAI. After receiving the message, the method includes removing the S-NSSAI from allowed Network Slice Selection Assistance Information (NSSAI).

[0042] A method of a communications device according to an exemplary aspect of the present disclosure includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes, if the timer expires, transmitting a second message for Network Slice Admission Control (NSAC) and a third message. The second message includes the S-NSSAI. The third message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0043] A method of a communications device according to an exemplary aspect of the present disclosure includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes, after receiving the first message, starting a timer for the S-NSSAI. The timer is set to a value associated with the S-NSSAI. The method includes, after starting the timer, receiving a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI. The method includes, after receiving the second message, stopping the timer. The method includes, after stopping the timer, receiving a third message related to release of the PDU session. The method includes, after receiving the third message, starting the timer. The method includes, if the timer expires, transmitting a fourth message. The fourth message is for removing the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI.

[0044] A method of a communications device according to an exemplary aspect of the present disclosure includes transmitting a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes receiving a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The method includes, after receiving the second message, starting a timer. The method includes, if there is no user plane activity for the PDU session until the timer expires, transmitting a third message. The third message indicates there is no user plane activity for the PDU session. The method includes, after transmitting the third message, receiving a fourth message. The method includes, after receiving the fourth message, performing a procedure for releasing the PDU session.

[0045] A method for a communications device according to an exemplary aspect of the present disclosure includes receiving a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The method includes transmitting a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The method includes, after transmitting the second message, receiving a third message. The third message indicates no user plane operation for the PDU session. The method includes, after receiving the third message, transmitting a fourth message. The fourth message is for performing a procedure to release the PDU session.

[0046] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to transmit a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to receive a second message when the S-NSSAI has not been used for a period of time. The second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time is associated with the S-NSSAI. The at least one hardware processor is configured to transmit a third message to remove the S-NSSAI from an allowed Network Slice Selection Assistance Information (NSSAI). The third message includes the S-NSSAI and the rejection cause.

[0047] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to start a timer for the S-NSSAI after receiving the first message. The timer is set to a value associated with the S-NSSAI. The at least one hardware processor is configured to perform Network Slice Admission Control (NSAC) if the timer expires. The at least one hardware processor is configured to transmit a second message after performing NSAC. The second message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0048] A User Equipment (UE) according to an example aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to register for Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to receive a message. The message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time. The period of time is associated with the S-NSSAI. After receiving the message, the at least one hardware processor is configured to remove the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI).

[0049] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to start a timer for the S-NSSAI after receiving the first message. The timer is set to a value associated with the S-NSSAI. The at least one hardware processor is configured to transmit a second message for Network Slice Admission Control (NSAC) and a third message when the timer expires. The second message includes the S-NSSAI. The third message includes the S-NSSAI and a rejection cause indicating expiration of the timer.

[0050] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to start a timer for the S-NSSAI after receiving the first message. The timer is set to a value associated with the S-NSSAI. The at least one hardware processor is configured to receive a second message associated with establishing a Protocol Data Unit (PDU) session for the S-NSSAI after starting the timer. The at least one hardware processor is configured to stop the timer after receiving the second message. The at least one hardware processor is configured to receive a third message associated with releasing the PDU session after stopping the timer. The at least one hardware processor is configured to start the timer after receiving the third message. The at least one hardware processor is configured to transmit a fourth message when the timer expires, the fourth message being for removing the S-NSSAI from the authorized Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI.

[0051] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to transmit a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to receive a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The at least one hardware processor is configured to start a timer after receiving the second message. The at least one hardware processor is configured to transmit a third message if there is no user plane activity for the PDU session until the timer expires. The third message indicates there is no user plane activity for the PDU session. The at least one hardware processor is configured to receive a fourth message after transmitting the third message. The at least one hardware processor is configured to perform a procedure for releasing the PDU session after receiving the fourth message.

[0052] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to receive a first message. The first message includes Single Network Slice Selection Assistance Information (S-NSSAI). The at least one hardware processor is configured to transmit a second message. The second message includes identification information of a Protocol Data Unit (PDU) session. The at least one hardware processor is configured to receive a third message after transmitting the second message. The third message indicates no user plane operation for the PDU session. The at least one hardware processor is configured to transmit a fourth message after receiving the third message. The fourth message is for performing a procedure to release the PDU session.

[0053] A method in a first core network device according to an example aspect of the present disclosure includes receiving a fourth message related to management of a network slice from a second core network device. The method includes, after receiving the fourth message, starting a timer for the network slice. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a fifth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use.

[0054] A method in a first core network device according to an example aspect of the present disclosure includes receiving a fourth message related to management of a network slice from a second core network device. The method includes starting a timer for the network slice after receiving the fourth message. The method includes detecting an operation related to the network slice. The method includes stopping the timer after detecting the operation.

[0055] A method by a third core network device according to an exemplary aspect of the present disclosure includes receiving a sixth message related to network management from a first core network device. The method includes analyzing data related to the network slice based on information received from the other core network device. The method includes, after receiving the sixth message, starting a timer for the network slice. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a seventh message to the first core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use. The first core network device manages network slice admission control.

[0056] A method of a third core network device according to an exemplary aspect of the present disclosure includes receiving a sixth message related to management of a network slice from a first core network device. The method includes analyzing data related to the network slice based on information received from the other core network device. The method includes starting a timer for the network slice after receiving the sixth message. The method includes detecting an operation related to the network slice. The method includes stopping the timer after detecting the operation. The first core network device manages network slice admission control.

[0057] A method by a first network slice control function node according to an example aspect of the present disclosure includes receiving an eighth message related to management of the network slice from a second core network device. The method includes, after receiving the eighth message, starting a timer for the network slice. The method includes detecting that the timer has expired. The method includes, after detecting that the timer has expired, sending a ninth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use.

[0058] A method by a first network slice control function node according to an exemplary aspect of the present disclosure includes receiving, from a second core network device, a tenth message related to management of the network slice. The method includes starting a timer for the network slice after receiving the tenth message. The method includes receiving, from the second network slice control function node, an eleventh message detecting an operation related to the network slice. The method includes stopping the timer after receiving the eleventh message.

[0059] A method in a third core network device node according to an exemplary aspect of the present disclosure includes transmitting first information related to management of a network slice to a first core network device to initiate control of the number of sessions based on a timer. The method includes receiving second information from the first core network device indicating that the control will be initiated. The method includes monitoring user plane activity related to the sessions after receiving the second information. The method includes transmitting third information to the first core network device indicating that no user plane activity is detected based on the monitoring. The method includes receiving fourth information from the first core network device indicating at least one of expiration of the timer or inactivity of the session within a period specified by the timer.

[0060] According to an exemplary embodiment of the present disclosure The The method in one core network device includes receiving, from a third core network device, fifth information related to management of a network slice. The method includes starting a timer for the network slice after receiving the fifth information. The method includes sending, to the third core network device, sixth information indicating that management will be initiated to start monitoring of user plane operations related to the session. The method includes receiving, from the third core network device, seventh information indicating that no user plane operations are detected based on the monitoring. The method includes sending, to the third core network device, eighth information indicating at least one of expiration of the timer or that the session has not been active within a period specified by the timer.

[0061] <First aspect> The first aspect discloses a mechanism that enables a network to deregister a UE from a network slice when the network slice has not been used for an extended period of time. For example, the first aspect discloses a mechanism that enables a network to deregister a UE from a network slice when there is no PDU session established by the UE in the network slice for a duration defined by a network operator. For example, the first aspect discloses a mechanism that enables a network to deregister a UE from a network slice when the number of UE registrations for the network slice has reached a certain threshold, e.g., a maximum number of UEs registered to the network slice. For example, the first aspect discloses a mechanism that enables a network to deregister a UE from a network slice when the network slice is overloaded.

[0062] For example, the first aspect can solve the problem of whether and how to enhance the system to ensure network-controlled behavior of network slice usage, including UE registration and PDU session establishment.

[0063] For example, the first aspect can solve a problematic situation in which a network slice cannot provide actual service operation to at least one of a UE and a PDU session when performing NSAC.

[0064] For example, the first aspect can solve a problematic situation when a network slice is used by a UE or a PDU session.

[0065] <First Example of First Aspect> The first example of the first aspect in FIG. 1 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NSACF 77 when the network slice has not been used for a long period of time. For example, the first example of the first aspect in FIG. 1 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NSACF 77 when there is no PDU session established by UE 3 in the network slice for a duration defined by the network operator, for example. For example, the first example of the first aspect in FIG. 1 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NSACF 77 when the number of UE registrations for the network slice has reached a certain threshold, for example, the maximum number of UEs registered to the network slice or a threshold defined by the operator. For example, the first example of the first aspect in FIG. 1 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NSACF 77 when the network slice is overloaded.

[0066] 1. UE3 registers with AMF70 for a network slice, for example, a network slice identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and supported by AMF70 at the network and the location of UE3. For example, UE3 may perform a registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 according to Non-Patent Document 3. A "network slice identified by an S-NSSAI" may be referred to as a "network slice" or an "S-NSSAI" in the present disclosure.

[0067] 2. If the network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 comply with Network Slice Admission Control (NSAC), AMF 70 registers UE 3 with NSACF 77 for each of these network slices for allocation control purposes, i.e., to control the number of UEs registered in the network slice so that it does not exceed the maximum number of UEs allowed to register for that network slice or a threshold number defined by the operator. AMF 70 may find out whether the network slice complies with NSAC by interacting with UDM 75 to obtain subscription information for UE 3 along with information about whether the network slice complies with NSAC. For example, AMF 70 may already have subscription information for UE 3 in the context of UE 3 within AMF 70. For example, AMF 70 may be configured with information about whether the network slice complies with NSAC.

[0068] If the requested network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 and requested by UE 3 are subject to NSAC, AMF 70 registers UE 3 with these network slices by sending an Nnsacf_NSAC_NumOfUEsUpdate_Request message to NSACF 77. To indicate to NSACF 77 that the network slices are subject to usage control or inactivity control, AMF 70 includes in the message the identification information (e.g., UE-Id) of UE 3, S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 identifying the requested network slices, and a parameter called "usage control" set to on or "inactivity control" set to on, or any other indication of the parameter. "Usage control" set to on or "inactivity control" set to on may indicate that UE 3 will be deregistered from the network slice if the network slice is not used by UE 3 for a certain period of time. "Identification information" may be referred to as an "identifier" in this disclosure.

[0069] "Usage control" or "inactivity control" to indicate to NSACF77 that the network slice is subject to usage control or inactivity control, or any other indication of a parameter, may be collectively referred to as "usage control" or "usage control" parameters.

[0070] For example, the "Usage Control" may be associated with the S-NSSAIs to which UE 3 registers. For example, the "Usage Control" set to ON may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0071] The AMF70 may also include a "usage control timer" parameter or an "inactivity control timer" parameter, or any other indication of a parameter, in the Nnsacf_NSAC_NumOfUEsUpdate_Request message to define the time or period during which the UE3 is deregistered from the network slice if the network slice is not used by the UE3, for example, if there is no service request or no PDU session is established by the UE3 in the network slice.

[0072] The "usage control timer" parameter or "inactivity control timer" parameter for determining the time or period during which UE3 is deregistered from the network slice if the network slice is not used by UE3, or any other indication of the parameter, may be collectively referred to as the "usage control timer" or "usage control timer" parameter.

[0073] For example, the AMF 70 may configure the "usage control timer" parameter based on a local configuration at the AMF 70 or a network operator policy within the AMF 70. Alternatively, the "usage control timer" parameter may be configured in the NSACF 77, or the "usage control timer" parameter is based on a network operator policy within the NSACF 77. For example, the AMF 70 or the NSACF 77 may determine the value of the "usage control timer" parameter.

[0074] For example, the "Usage Control Timer" parameter may be associated with the S-NSSAI to which UE3 registers. For example, the "Usage Control Timer" may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be the same for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, or may be different for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be expressed as a value associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0075] For example, AMF 70 may send an Nnsacf_NSAC_NumOfUEsUpdate_Request message during the registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. For example, AMF 70 may send a message related to the network slice to NSACF 77. For example, AMF 70 may send a message related to the management of the network slice to NSACF 77. For example, AMF 70 may send a message related to the management of the number of UEs registered in the network slice to NSACF 77.

[0076] The Nnsacf_NSAC_NumOfUEsUpdate_Request message may be sent for an NSAC.

[0077] For example, if the number of registered UEs in a network slice exceeds the maximum number of UEs allowed to register to that network slice or a threshold number defined by the operator, NSACF 77 may not start the usage control timer for the network slice (e.g., S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3). In this case, NSACF 77 may send information to AMF 70 indicating that the UE identified by the UE-Id cannot register to the network slice.

[0078] 3. The NSACF 77 receives the Nnsacf_NSAC_NumOfUEsUpdate_Request message from the AMF 70.

[0079] If the network slice to which UE3 registers is subject to usage control or inactivity control, for example, if the "usage control" parameter from AMF70 is set to on, NSACF77 starts a timer that measures the time when the network slice is not being used by UE3, for example, the time when no service is requested or no PDU session is established by UE3 in the network slice, or no data is exchanged in an established PDU session. The timer may be referred to, for example, as a "usage control timer" or an "inactivity control timer," or any other indication of a timer. The "usage control timer" or an "inactivity control timer," or any other indication of a timer, may be collectively referred to as a "usage control timer."

[0080] The "Usage Control Timer" or "Inactivity Control Timer" may be set by the operator to a value configured in the NSACF 77. The "Usage Control Timer" or "Inactivity Control Timer" may be set to a value indicated by the AMF 70 in the "Usage Control Timer" or "Inactivity Control Timer" parameter.

[0081] The NSACF 77 executes a "usage control timer" for each network slice subject to usage control, e.g., a network slice for which the "usage control" parameter is set to ON. For example, the NSACF 77 executes a "usage control timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The "usage control timer" may be controlled per UE in the present disclosure. For example, the NSACF 77 may control a "usage control timer" for each UE identified by a UE-Id. For example, the NSACF 77 may execute a "usage control timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 for UE 3.

[0082] 4. At some stage, for example, UE3 having an authorized NSSAI including S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, requests service or PDU session establishment in S-NSSAI-1 and S-NSSAI-2.

[0083] 5. SMF 71 registers the PDU sessions established in S-NSSAI-1 and S-NSSAI-2 with NSACF 77 for allocation control of the maximum number of PDU sessions. For example, NSACF 77 detects an operation related to a network slice (e.g., a network slice identified by S-NSSAI-1 or S-NSSAI-2). For example, SMF 71 may send a message to NSACF 77 to register the PDU sessions established in S-NSSAI-1 and S-NSSAI-2. The message may be referred to as a registration notification.

[0084] 6. If the network slices identified by S-NSSAI-1 and S-NSSAI-2 are subject to usage control, i.e., if NSACF 77 has active usage control timers running for UE 3 for S-NSSAI-1 and S-NSSAI-2, NSACF 77 stops the "usage control timer" for S-NSSAI-1 and the "usage control timer" for S-NSSAI-2 because these two network slices are being used by UE 3 in the network slices identified by S-NSSAI-1 and S-NSSAI-2, i.e., a PDU session is established, before the usage control timers for S-NSSAI-1 and S-NSSAI-2 expire. For example, when NSACF 77 receives a registration notification from SMF 71 in step 5, NSACF 77 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 started in step 3. For example, when NSACF 77 receives a registration notification from SMF 71 in step 5, NSACF 77 may recognize that the network slice identified by S-NSSAI-1 and S-NSSAI-2 is being used by UE 3 in the network slice identified by S-NSSAI-1 and S-NSSAI-2, i.e., a PDU session is being established, and NSACF 77 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 that were started in step 3. For example, when NSACF 77 receives a message indicating an operation related to the network slice identified by S-NSSAI-1 or S-NSSAI-2, NSACF 77 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 that were started in step 3. The registration notification may be expressed as a message related to the PDU session for S-NSSAI-1 and S-NSSAI-2.

[0085] When UE3 stops using the network slice identified by S-NSSAI-1 and S-NSSAI-2, i.e., when UE3 releases the PDU session in S-NSSAI-1 and S-NSSAI-2, NSACF77 restarts the usage control timer for S-NSSAI-1 and S-NSSAI-2. For example, when NSACF77 receives a release notification for the PDU session in S-NSSAI-1 and S-NSSAI-2 from SMF71, NSACF77 may restart the usage control timer for S-NSSAI-1 and S-NSSAI-2.

[0086] 7. The "usage control timer" for S-NSSAI-3 for UE3 expires. The "usage control timer" for UE3 for S-NSSAI-3 expires because UE3 has not used S-NSSAI-3, i.e., UE3 has not requested a service or established a PDU session in S-NSSAI-3 for some time.

[0087] 8. The NSACF 77 sends an Nnsacf_NSAC_DeregistrationNotification message to the AMF 70 including the UE_Id, S-NSSAI-3, and a reject cause set to "Usage Control Timer Expired" to indicate that the NSACF 77 wants to deregister the UE 3 for S-NSSAI-3 because the UE 3 has not used S-NSSAI-3 until the "Usage Control Timer" for S-NSSAI-3 for the UE 3 has expired. For example, after step 7, the NSACF 77 may send a message to the AMF 70 indicating that the network slice (e.g., the network slice identified by S-NSSAI-3) is not in use. For example, the NSACF 77 may send an Nnsacf_NSAC_DeregistrationNotification message to the AMF 70 if the S-NSSAI-3 has not been used for a period of time. The NSACF 77 may include the parameters described below in the Nnsacf_NSAC_DeregistrationNotification message to the AMF 70.

[0088] UE-Id (UE-Id) - identification of the UE 3 to be deregistered.

[0089] -S-NSSAI-3 (S-NSSAI-3) - Network slice identification information from which UE3 is deregistered by NSACF77, network slice identification information that is not used by UE3, or network slice identification information from which the "usage control timer" expires.

[0090] -Reject cause which is set to 'usage control timer expired' - This reject cause indicates the reason for deregistration of UE3 from S-NSSAI-3. For example, the reject cause may indicate that UE3 has not requested a service or established a PDU session in the network slice identified by S-NSSAI-3 until the 'usage control timer' for UE3 expired. The reject cause may be associated with S-NSSAI-3. A reject cause set to 'usage control timer expired' may be expressed as reject cause = 'usage control timer expired'. The reject cause may indicate that UE3 has not used the network slice identified in S-NSSAI-3 until the 'usage control timer' for UE3 expired. The reject cause may indicate that S-NSSAI-3 has not been used for a period of time. The reject cause may indicate that S-NSSAI-3 has not been used for a period of time identified by the 'usage control timer' parameter. The cause of denial may indicate the expiration of a "usage control timer."

[0091] NSACF77 also updates the number of UEs registered for S-NSSAI-3 by decrementing the number of registered UEs for S-NSSAI-3 by one, and NSACF77 also removes the identification information, e.g., UE-Id, of UE3 from the list of UEs registered for S-NSSAI-3.

[0092] For example, when NSACF 77 updates the number of UEs registered in S-NSSAI-3, NSACF 77 may perform allocation control (eg, NSAC) for the registered UEs according to section 4.2.11 of Non-Patent Document 3.

[0093] For example, NSACF 77 may send an Nnsacf_NSAC_DeregistrationNotification message when the "Usage Control Timer" for S-NSSAI-3 for UE 3 expires.

[0094] For example, NSAC by NSACF77 (e.g., decrementing or reducing the number of registered UEs for S-NSSAI-3 by one) may be performed when the "usage control timer" for S-NSSAI-3 for UE3 expires.

[0095] For example, NSAC by NSACF 77 (eg, decrementing or decreasing the number of registered UEs for S-NSSAI-3 by one) may be performed when the period indicated by the "Usage Control Timer" parameter elapses.

[0096] 9. The AMF 70 receives an Nnsacf_NSAC_DeregistrationNotification message from the NSACF 77. Upon receiving the Nnsacf_NSAC_DeregistrationNotification message, if the UE 3 is in connected mode, the AMF 70 may deregister the UE 3 for the S-NSSAI-3 via a UE Configuration Update message, in which the AMF 70 removes the S-NSSAI-3 from the Allowed NSSAIs and adds the S-NSSAI-3 to the Rejected NSSAI. The AMF 70 may send a UE Configuration Update message to the UE (e.g., UE 3) identified by the UE-Id. For example, the UE Configuration Update message may be represented as a UCU message. For example, the AMF 70 may include information in the UCU message to instruct the UE 3 to remove the S-NSSAI-3 from the Allowed NSSAIs and add the S-NSSAI-3 to the Rejected NSSAI. For example, when AMF70 sends a UCU message, AMF70 removes S-NSSAI-3 from the allowed NSSAI for UE3 stored in AMF70 and adds S-NSSAI-3 to the rejected NSSAI for UE3 stored in AMF70.

[0097] The AMF 70 also includes a rejection cause for the S-NSSAI-3 in the UCU message, for example, a rejection cause set to "Usage Control Timer Expiration" or "Inactivity Control Timer Expiration," to indicate that the network slice is rejected because it has not been used by the UE 3 until the usage control timer for the UE 3 for that network slice expires. The rejection cause may be the same as that in the Nnsacf_NSAC_DeregistrationNotification message. The rejection cause may indicate the same as that in the Nnsacf_NSAC_DeregistrationNotification message.

[0098] Alternatively, AMF70 may use the existing UE deregistration procedure by AMF70 sending a deregistration request message to UE3 that includes a network slice, for example, S-NSSAI-3, where UE3 is denied registration, and a rejection cause set to "Usage Control Timer Expired".

[0099] Upon receiving the Nnsacf_NSAC_DeregistrationNotification message, if the UE 3 is in idle mode, the AMF 70:

[0100] - After paging the UE 3 and connecting with the UE 3, the AMF 70 sends a UE CONFIGURATION UPDATE message to the UE 3 with a rejection S-NSSAI-3 and a rejection cause set to "Usage Control Timer Expired", or

[0101] - Stores the information in the Nnsacf_NSAC_DeregistrationNotification message from the NSACF 77 until the UE 3 returns to a connected state to the network, for example for service or PDU session establishment. When the UE 3 returns to a connected state to the network, the AMF 70 provides the UE 3 with a rejection S-NSSAI-3 and a rejection cause set to "Usage Control Timer Expired" via a UE Configuration Update message.

[0102] The AMF 70 may store information indicating whether the UE 3 is in a connected mode or an idle mode. The AMF 70 may receive information indicating whether the UE 3 is in a connected mode or an idle mode from another network node. The AMF 70 may determine whether the UE 3 is in a connected mode or an idle mode based on the information indicating whether the UE 3 is in a connected mode or an idle mode. A UCU message or a deregistration request message may be sent for at least one of removing the S-NSSAI-3 from the allowed NSSAI and adding the S-NSSAI-3 to the rejected NSSAI.

[0103] 10. If UE3 receives a registration rejection for a network slice, e.g., S-NSSAI-3, via a UE Configuration Update message or a UE Deregistration message with the rejection cause set to "Usage Control Timer Expired", UE3 removes the Rejected S-NSSAI-3 from the Allowed NSSAIs, and UE3 continues registration for S-NSSAI-1 and S-NSSAI-2. UE3 may add the Rejected S-NSSAI-3 to the Rejected NSSAIs.

[0104] 11. Optionally, UE3 may refresh its registration by triggering a new registration procedure for S-NSSAI-1 and S-NSSAI-2 according to the registration procedure in Non-Patent Document 3.

[0105] For example, a communications device capable of AMF 70 may transmit a first message. The first message may include a Single Network Slice Selection Assistance Information (S-NSSAI). The communications device may receive a second message if the S-NSSAI has not been used for a period of time. The second message may include the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for the period of time. The period of time may be associated with the S-NSSAI. The communications device may transmit a third message to remove the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI). The third message may include the S-NSSAI and the rejection cause.

[0106] For example, a communications device capable of NSACF 77 may receive a first message. The first message may include Single Network Slice Selection Assistance Information (S-NSSAI). After receiving the first message, the communications device may start a timer for the S-NSSAI. The timer may be set to a value associated with the S-NSSAI. The communications device may perform Network Slice Admission Control (NSAC) if the timer expires. After performing NSAC, the communications device may transmit a second message. The second message may include the S-NSSAI and a reject cause indicating the expiration of the timer.

[0107] For example, a User Equipment (UE) corresponding to UE3 may register for Single Network Slice Selection Assistance Information (S-NSSAI). The UE may receive a message. The message may include the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time. The period of time may be associated with the S-NSSAI. After receiving the message, the UE may remove the S-NSSAI from the allowed Network Slice Selection Assistance Information (NSSAI).

[0108] For example, a first core network device corresponding to the NSACF 77 may receive a message related to management of a network slice from a second core network device corresponding to the AMF 70. After receiving the message, the first core network device may start a timer for the network slice. The first core network device may detect that the timer has expired. After detecting that the timer has expired, the first core network device may send a message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not being used.

[0109] For example, a first core network device corresponding to the NSACF 77 may receive a message related to management of a network slice from a second core network device corresponding to the AMF 70. After receiving the message, the first core network device may start a timer for the network slice. The first core network device may detect an operation related to the network slice. After detecting the operation, the first core network device may stop the timer.

[0110] Based on the above, it is possible to solve the above problems, such as whether and how to improve the system to ensure network-controlled behavior of network slice usage, including UE registration and PDU session establishment.

[0111] <Modification 1 of the first example of the first aspect> In step 8 of Figure 1, the NSACF 77 may include a network slice usage back-off timer in the Nnsacf_NSAC_DeregistrationNotification message to the AMF 70. If the network slice usage back-off timer is included by the NSACF 77, the AMF 70 relays the network slice usage back-off timer to the UE 3 in step 9. If the UE 3 receives a rejection for a network slice (e.g., S-NSSAI-3) with the rejection cause set to "usage control timer expired" and the network slice usage back-off timer set to "usage control timer expired," the UE 3 starts the network slice usage back-off timer, and the UE 3 does not request registration for the rejected network slice, e.g., S-NSSAI-3, while the network slice usage back-off timer for S-NSSAI-3 is running. The UE 3 may request registration for the rejected network slice, e.g., S-NSSAI-3, if the network slice usage back-off timer for S-NSSAI-3 expires. Cell reselection and registration area update by UE3 do not reset the network slice usage backoff timer in UE3. Upon PLMN change, UE3 resets the network slice usage backoff timer if it is still running. The network slice usage backoff timer may be associated with a rejected network slice (e.g., S-NSSAI-3).

[0112] <Modification 2 of the first example of the first aspect> If the number of UEs registered to S-NSSAI-3 reaches a threshold, e.g., the maximum number of UEs registered to S-NSSAI-3, NSACF 77 may trigger an Nnsacf_NSAC_DeregistrationNotification message to AMF 70. If the number of UEs registered to S-NSSAI-3 reaches a threshold, e.g., the maximum number of UEs registered to S-NSSAI-3, it may mean that the network slice identified by S-NSSAI-3 is overloaded. In this case, the rejection cause in the Nnsacf_NSAC_DeregistrationNotification message indicates that the maximum number of UEs registered to the network slice, e.g., S-NSSAI-3, has been reached. In step 9, AMF 70 communicates the rejected S-NSSAI-3 and a new rejection cause set to "the maximum number of UEs registered to the network slice has been reached" to UE 3, and UE 3 removes the rejected network slice, e.g., S-NSSAI-3, from the allowed NSSAIs. The new reject cause set to "The maximum number of UEs registered to the network slice has been reached" may indicate that the maximum number of UEs registered to the network slice, e.g., S-NSSAI-3, has been reached. In addition, the Nnsacf_NSAC_DeregistrationNotification message may include a back-off timer parameter for the rejected network slice, e.g., S-NSSAI-3. The back-off timer parameter may be included in the UCU message or the deregistration request message. If the back-off timer parameter is included in the UCU message or the deregistration request message by the AMF 70, the UE 3 starts a timer using the value provided in the back-off timer parameter, and the UE 3 does not attempt another registration to the rejected network slice, e.g., S-NSSAI-3, while the timer is still running. The UE 3 may attempt another registration to the rejected network slice, e.g., S-NSSAI-3, if the timer expires.

[0113] <Modification 3 of the first example of the first aspect> If there is another network slice (e.g., S-NSSAI-4) supported by AMF70 and UE3 subscribes to another network slice (e.g., S-NSSAI-4) that can provide the same service as, a similar service to, or an alternative service to, the rejected S-NSSAI-3, then in step 9 of FIG. 1, AMF70 may provide UE3 with a substitute network slice for the rejected S-NSSAI-3. In that case, AMF70 includes the substitute network slice (e.g., S-NSSAI-4) in the authorized NSSAI for UE3 in step 9, and UE3 becomes registered for S-NSSAI-1, S-NSSAI-2, and the substitute network slice (e.g., S-NSSAI-4). For example, AMF70 may store information indicating the substitute network slice (e.g., S-NSSAI-4). For example, AMF70 may store information indicating a network slice to which UE3 is subscribed and which may provide the same, similar, or alternative service as the rejected S-NSSAI-3.

[0114] <Modification 4 of the first example of the first aspect> When UE3 releases the PDU session in S-NSSAI-1 and S-NSSAI-2 established in step 4, SMF71 contacts NSACF77 for PDU session allocation control. For example, when SMF71 receives notification from another node (e.g., UE3) regarding the release of the PDU session in S-NSSAI-1 and S-NSSAI-2, SMF71 may contact NSACF77 for PDU session allocation control.

[0115] In this case, NSACF 77 restarts the usage control timers for S-NSSAI-1 and S-NSSAI-2 for UE 3 when the associated PDU sessions are released.

[0116] <Modification 5 of the first example of the first aspect> In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter.

[0117] For example, the NSACF 77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control based on the inclusion of the S-NSSAI and usage control timer parameters.

[0118] In step 2, if NSACF77 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without usage control parameters, NSACF77 may start usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 3, and the subsequent process may be performed according to the first example of the first aspect.

[0119] In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter and the usage control timer parameter.

[0120] For example, based on receiving an Nnsacf_NSAC_NumOfUEsUpdate_Request message, NSACF77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control.

[0121] If in step 2 the NSACF 77 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without usage control parameters and usage control timer parameters, the NSACF 77 may start the usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 3, and the subsequent process may be performed according to the first example of the first aspect. In this case, the NSACF 77 may configure the values ​​of the usage control timers based on its local configuration or an operator's policy stored in the NSACF 77.

[0122] <Second Example of the First Aspect> The second example of the first aspect in FIG. 2 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NWDAF 76 when the network slice has not been used for an extended period of time. For example, the second example of the first aspect in FIG. 2 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NWDAF 76 when there is no PDU session established by UE 3 in the network slice for a duration defined by the network operator. For example, the second example of the first aspect in FIG. 2 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NWDAF 76 when the number of UE registrations for the network slice has reached a certain threshold, e.g., a maximum number of UEs registered to the network slice. For example, the second example of the first aspect in FIG. 2 discloses a mechanism that enables the network to deregister UE 3 from the network slice via NWDAF 76 when the network slice is overloaded. Because the NWDAF 76 may interact with multiple or all NSACFs 77 in the PLMN, the NWDAF 76 may make a global decision regarding network slice usage control. For example, if the sum of the number of UEs registered in the network slice at all NSACFs 77 in the PLMN exceeds the maximum number of UEs allowed to register to the network slice according to a Service Level Agreement (SLA) with a third party, the NWDAF 76 may make a decision to deregister a UE, e.g., UE 3, from using the network slice based on the cumulative number of UEs registered in the network slice via all of the NSACFs in the PLMN.

[0123] 1. The UE 3 registers with the AMF 70 for a network slice, for example, identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and supported by the network and the AMF 70 at the location of the UE 3. For example, the UE 3 may perform a registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 according to non-patent document 3.

[0124] 2. If the network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 comply with Network Slice Admission Control (NSAC), AMF 70 registers UE 3 with NSACF 77 for each of these network slices for allocation control, i.e., to control the number of UEs registered in a network slice so that it does not exceed the maximum number of UEs allowed to register for that network slice. AMF 70 may find out whether a network slice complies with NSAC by interacting with UDM 75 to obtain subscription information for UE 3 along with information about whether the network slice complies with NSAC. For example, AMF 70 may already have subscription information for UE 3 in the context of UE 3 within AMF 70. For example, AMF 70 may be configured with information about whether a network slice complies with NSAC.

[0125] If the requested network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 and requested by UE 3 are subject to NSAC, AMF 70 registers UE 3 with these network slices by sending an Nnsacf_NSAC_NumOfUEsUpdate_Request message to NSACF 77. To indicate to NSACF 77 that the network slices are subject to usage control or inactivity control, AMF 70 includes in the message the identification information (e.g., UE-Id) of UE 3, S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 identifying the requested network slices, and a parameter called "usage control" set to on or "inactivity control" set to on, or any other indication of the parameter. "Usage control" set to on or "inactivity control" set to on may indicate that UE 3 will be deregistered from the network slice if the network slice is not used by UE 3 for a certain period of time.

[0126] "Usage control" or "inactivity control" to indicate to NSACF77 that the network slice is subject to usage control or inactivity control, or any other indication of a parameter, may be collectively referred to as "usage control" or "usage control" parameters.

[0127] For example, the "Usage Control" may be associated with the S-NSSAIs to which UE 3 registers. For example, the "Usage Control" set to ON may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0128] The AMF70 may also include a "usage control timer" parameter or an "inactivity control timer" parameter, or any other indication of a parameter, in the Nnsacf_NSAC_NumOfUEsUpdate_Request message to define the time or period during which the UE3 is deregistered from the network slice if the network slice is not used by the UE3, for example, if there is no service request or no PDU session is established by the UE3 in the network slice.

[0129] The "usage control timer" parameter or "inactivity control timer" parameter for determining the time or period during which UE3 is deregistered from the network slice if the network slice is not used by UE3, or any other indication of the parameter, may be collectively referred to as the "usage control timer" or "usage control timer" parameter.

[0130] For example, the AMF 70 may configure the "usage control timer" parameter based on a local configuration at the AMF 70 or a network operator policy within the AMF 70. Alternatively, the "usage control timer" parameter may be configured in the NSACF 77, or the "usage control timer" parameter is based on a network operator policy within the NSACF 77. For example, the AMF 70 or the NSACF 77 may determine the value of the "usage control timer" parameter.

[0131] For example, the "Usage Control Timer" parameter may be associated with the S-NSSAI to which UE3 registers. For example, the "Usage Control Timer" may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be the same for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, or may be different for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be expressed as a value associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0132] For example, AMF70 may send an Nnsacf_NSAC_NumOfUEsUpdate_Request message during the registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0133] 3. The NSACF 77 receives the Nnsacf_NSAC_NumOfUEsUpdate_Request message from the AMF 70.

[0134] The NSACF 77 may initiate allocation control for network slices provided by the AMF 70, such as S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. For example, the NSACF 77 may initiate control over the maximum number of registered UEs for these network slices in accordance with clause 4.2.11 of 3GPP TS 26.2444-10. If the network slices provided by the AMF 70, e.g., S-NSSAI-1, S-NSSAI-2, S-NSSAI-3, are subject to usage control indicated by the AMF 70, e.g., via a "usage control" parameter set to on, or indicated by a configuration in the NSACF 77 (e.g., when the NSACF 77 receives the "usage control" parameter set to on, or indicated by a configuration in the NSACF 77), the NSACF 77 sends a Nnwdaf_SliceUsageControl message to the NWDAF 76, including the UE_Id, S-NSSAI-1, S-NSSAI-2, S-NSSAI-3, the usage control set to on, and a usage control timer. For example, the NWDAF 76 analyzes the usage of the network slices per UE, e.g., per UE 3, or per multiple UEs, based on inputs from one or more NSACFs and other network functions, such as an AMF, e.g., AMF 70, and an SMF, e.g., SMF 71. For example, the NWDAF 76 may analyze data related to the network based on other factors relative to the network slice, such as network slice congestion. The NSACF 77 may include the parameters described below in the Nnwdaf_SliceUsageControl message.

[0135] UE-Id (UE-Id) - Identification of the UE 3 subject to usage control.

[0136] One or more network slices - for example, S-NSSAI-1, S-NSSAI-2, S-NSSAI-3 subject to usage control.

[0137] A usage control parameter set to ON to indicate that the included network slices (e.g., S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3) are subject to usage control. The usage control parameter may be per network slice or per multiple network slices.

[0138] Usage control timer - a time value indicating the duration for which UE3 can remain registered to the network slice without using the network slice, i.e., without requesting a service in the network slice or establishing a PDU session in the network slice. The usage control timer may be the same as the "usage control timer" parameter received from AMF70. The usage control timer may be configured within NSACF77 or may be based on an operator policy in NSACF77. For example, NSACF77 may determine the value of the usage control timer based on an operator policy or a local configuration in NSACF77. For example, the usage control timer may indicate the time or period for which UE3 is deregistered from the network slice when the network slice is not used by UE3, e.g., when there is no service request or a PDU session is not established by UE3 in the network slice.

[0139] For example, the NSACF 77 may send a message related to the network slice to the NWDAF 76. For example, the NSACF 77 may send a message related to the management of the network slice to the NWDAF 76. For example, the NSACF 77 may send a message related to the management of the number of UEs registered in the network slice to the NWDAF 76.

[0140] 4. The NWDAF 76 receives the Nnwdaf_SliceUsageControl message from the NSACF 77.

[0141] If the network slice to which UE 3 registers is subject to usage control or inactivity control, for example, if the "usage control" parameter from NSACF 77 in the Nnwdaf_SliceUsageControl message is set to on, NWDAF 76 starts a timer that measures the time the network slice is not being used by UE 3, for example, the time when no service is requested or no PDU session is established by UE 3 in that network slice, or no data is exchanged in an established PDU session. The timer may be referred to, for example, as a "usage control timer" or an "inactivity control timer," or any other indication of a timer. The "usage control timer" or an "inactivity control timer," or any other indication of a timer, may be collectively referred to as a "usage control timer."

[0142] The "Usage Control Timer" or "Inactivity Control Timer" may be set to a value configured in the NWDAF 76 by an operator. The Usage Control Timer may be configured within the NWDAF 76 or may be based on operator policy in the NWDAF 76. For example, the NWDAF 76 may set the "Usage Control Timer" to a value configured in the NWDAF 76 based on operator policy or local configuration in the NWDAF 76. "ofThe NWDAF 76 may determine a value for the "Usage Control Timer" or "Inactivity Control Timer." The "Usage Control Timer" or "Inactivity Control Timer" may be set to a value indicated by the AMF 70 in the "Usage Control Timer" parameter or the "Inactivity Control Timer." The "Usage Control Timer" or "Inactivity Control Timer" may be set to a value indicated by the NSACF 77 in the Usage Control Timer. The NWDAF 76 executes a "Usage Control Timer" for each network slice subject to usage control, e.g., a network slice for which the "Usage Control" parameter is set to on. For example, the NWDAF 76 executes a "Usage Control Timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The "Usage Control Timer" may be controlled per UE by the NWDAF 76. For example, the NWDAF 76 may control a "Usage Control Timer" for each UE identified by a UE-Id. For example, the NWDAF 76 may execute a "Usage Control Timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 for UE 3.

[0143] 5. At some stage, for example, UE3 having authorized NSSAIs including S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, requests service or PDU session establishment for S-NSSAI-1 and S-NSSAI-2.

[0144] 6. SMF 71 registers the PDU sessions established in S-NSSAI-1 and S-NSSAI-2 with NSACF 77 for allocation control of the maximum number of PDU sessions. For example, NSACF 77 detects an operation related to a network slice (e.g., a network slice identified by S-NSSAI-1 or S-NSSAI-2). For example, SMF 71 may send a message to NSACF 77 to register the PDU sessions established in S-NSSAI-1 and S-NSSAI-2. The message may be referred to as a registration notification.

[0145] 7. The NSACF 77 sends a Nnwdaf_SliceUsageControl message to the NWDAF 76, including the UE_Id, S-NSSAI-1, S-NSSAI-2, S-NSSAI-3, and the established PDU session. For example, the NWDAF 76 analyzes network slice usage per UE, e.g., per UE 3, or per multiple UEs, based on input from one or more NSACFs and other network functions, such as an AMF, e.g., AMF 70, and an SMF, e.g., SMF 71. The NSACF 77 may include the parameters described below in the Nnwdaf_SliceUsageControl message.

[0146] UE-Id (UE-Id) - Identification of the UE 3 subject to usage control.

[0147] -One or more network slice parameters - for example, S-NSSAI-1, S-NSSAI-2, S-NSSAI-3 according to usage control. For example, the one or more network slice parameters may indicate the network slice in which the PDU session is established. For example, if NSACF77 receives information from SMF71 in step 6 indicating that the PDU session is established in the network slices identified by S-NSSAI-1 and S-NSSAI-2, NSACF77 may set the one or more network slice parameters to S-NSSAI-1 and S-NSSAI-2. The one or more network slice parameters may be expressed as parameters associated with one or more network slices.

[0148] The "PDU session established" parameter indicates to the NWDAF 76 that a PDU session related to the associated network slice in one or more network slice parameters in this message has been established. For example, if the NSACF 77 sets one or more network slice parameters to S-NSSAI-1 and S-NSSAI-2, the NSACF 77 may set the "PDU session established" parameter to indicate that a PDU session related to S-NSSAI-1 and S-NSSAI-2 has been established. The "PDU session established" parameter may be referred to as an established PDU session parameter.

[0149] For example, the NSACF 77 may send a message related to the network slice to the NWDAF 76. For example, the NSACF 77 may send a message related to the management of the network slice to the NWDAF 76. For example, the NSACF 77 may send a message related to the management of the number of UEs registered in the network slice to the NWDAF 76. For example, the NSACF 77 may send a message related to a PDU session to the NWDAF 76. For example, the NSACF 77 may send a message to the NWDAF 76 indicating that a PDU session has been established. For example, the NSACF 77 may send a message to the NWDAF 76 indicating that a PDU session related to at least one of S-NSSAI-1 and S-NSSAI-2 has been established. For example, the NWDAF 76 detects an operation related to the network slice (e.g., an operation related to the network slice identified by S-NSSAI-1 or S-NSSAI-2).

[0150] 8. The NWDAF 76 receives an Nnwdaf_SliceUsageControl message from the NSACF 77. If the network slices identified by S-NSSAI-1 and S-NSSAI-2 are subject to usage control, i.e., if the NWDAF 76 has active usage control timers running for the UE 3 for S-NSSAI-1 and S-NSSAI-2, the NWDAF 76 stops the "usage control timer" for S-NSSAI-1 and the "usage control timer" for S-NSSAI-2 because these two network slices are being used by the UE 3 in the network slices identified by S-NSSAI-1 and S-NSSAI-2, i.e., a PDU session is established, before the usage control timers for S-NSSAI-1 and S-NSSAI-2 expire. For example, if the NWDAF 76 receives an Nnwdaf_SliceUsageControl message from the NSACF 77, the NWDAF 76 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 that started in step 4. For example, if the NWDAF 76 receives an Nnwdaf_SliceUsageControl message from the NSACF 77 in step 7, the NWDAF 76 may recognize, based on at least one of the parameters in the Nnwdaf_SliceUsageControl message, that the network slice identified by S-NSSAI-1 and S-NSSAI-2 is being used, i.e., a PDU session is established by the UE 3 in the network slice identified by S-NSSAI-1 and S-NSSAI-2, and the NWDAF 76 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 that started in step 4.For example, by using at least one of the one or more network slice parameters and the "established PDU session" parameter, the NWDAF 76 may recognize that the network slice identified by S-NSSAI-1 and S-NSSAI-2 is being used, i.e., a PDU session is established by the UE 3 in the network slice identified by S-NSSAI-1 and S-NSSAI-2. For example, if the NWDAF 76 receives a message indicating an operation related to the network slice identified by S-NSSAI-1 or S-NSSAI-2, the NWDAF 76 may stop the usage control timers for S-NSSAI-1 and S-NSSAI-2 that started in step 4. For example, the NWDAF 76 may detect an operation related to the network slice (e.g., the network slice identified by S-NSSAI-1 or S-NSSAI-2). For example, upon receiving a message from NSACF 77, NWDAF 76 may detect an operation related to a network slice (e.g., a network slice identified by S-NSSAI-1 or S-NSSAI-2).

[0151] When UE 3 stops using the network slice identified by S-NSSAI-1 and S-NSSAI-2, i.e., when UE 3 releases the PDU session in S-NSSAI-1 and S-NSSAI-2, NWDAF 76 restarts the usage control timer for S-NSSAI-1 and S-NSSAI-2. For example, when NSACF 77 receives a release notification for the PDU session in S-NSSAI-1 and S-NSSAI-2 from SMF 71, NSACF 77 may send a release notification to NWDAF 76. When NWDAF 76 receives the release notification, NWDAF 76 may restart the usage control timer for S-NSSAI-1 and S-NSSAI-2. The release notification may be a Nnwdaf_SliceUsageControl message. When indicating the release of a PDU session, the Nnwdaf_SliceUsageControl message may include a UE-Id (e.g., identification information of the UE 3), one or more network slice parameters, and a "released PDU session" parameter. The one or more network slice parameters may indicate the network slice from which the PDU session is being released (e.g., network slice identities associated with the released PDU session, e.g., S-NSSAI-1 and S-NSSAI-2). The "released PDU session" parameter may indicate that the PDU session associated with the associated network slice (e.g., the network slice identified by S-NSSAI-1 and S-NSSAI-2) is being released. The released PDU session parameter may indicate that the PDU session associated with S-NSSAI-1 and S-NSSAI-2 is being established.

[0152] 9. The "usage control timer" for S-NSSAI-3 for UE3 expires. The "usage control timer" for UE3 for S-NSSAI-3 expires because UE3 has not used S-NSSAI-3, i.e., UE3 has not requested a service or established a PDU session in S-NSSAI-3 for some time. For example, NWDAF 76 may detect that the usage control timer for S-NSSAI-3 for UE3 has expired.

[0153] 10. The NWDAF 76 sends an Nnwdaf_DeregistrationRequest message including the UE_Id and S-NSSAI-3 to the NSACF 77, where allocation control is performed for the network slice identified by S-NSSAI-3 according to clause 4.2.11 of 3GPP TS 36.110.2013-01-01 11, i.e., as a result, the NSACF 77 may deregister UE 3 from S-NSSAI-3, decrement the number of UEs registered for S-NSSAI-3 by one, and remove the identity of UE 3 from the list of UEs registered for S-NSSAI-3. The UE_Id may be the identity of UE 3. When the NSACF 77 receives the Nnwdaf_DeregistrationRequest message, the NSACF 77 updates the number of UEs registered for S-NSSAI-3 by decrementing the number of registered UEs for S-NSSAI-3 by one, and the NSACF 77 also removes the identity of UE 3, e.g., the UE-Id, from the list of UEs registered for S-NSSAI-3. For example, NWDAF 76 sends an Nnwdaf_DeregistrationRequest message when the "usage control timer" for S-NSSAI-3 for UE 3 expires. The Nnwdaf_DeregistrationRequest message may include the network slice identity for which the "usage control timer" for UE 3 expires. When the "usage control timer" for UE 3 for S-NSSAI-3 expires, NWDAF 76 may include S-NSSAI-3 in the Nnwdaf_DeregistrationRequest message as the network slice identity for which the "usage control timer" for UE 3 expires.

[0154] The Nnwdaf_DeregistrationRequest message is sent to the NSAC F 77.

[0155] 11. The NWDAF 76 may also send to the AMF 70 a Nnwdaf_DeregistrationNotification message including the UE_Id and S-NSSAI-3, with a reject cause set to "Usage Control Timer Expired", to indicate that the UE 3 is deregistered from the network slice identified by S-NSSAI-3 because the UE 3 has not used S-NSSAI-3 until the "Usage Control Timer" for S-NSSAI-3 for the UE 3 expires. For example, after step 8 or step 9, the NWDAF 76 may send to the AMF 70 a message indicating that the network slice (e.g., the network slice identified by S-NSSAI-3) is not in use. The NWDAF 76 may include the parameters described below in the Nnwdaf_DeregistrationNotification message to the AMF 70.

[0156] UE-Id (UE-Id) - Identification of the UE 3 to be deregistered

[0157] -S-NSSAI-3 (S-NSSAI-3) - Network slice identification information from which UE3 is deregistered by NSACF77, network slice identification information that is not used by UE3, or network slice identification information from which the "usage control timer" expires.

[0158] -Reject cause which is set to 'usage control timer expired' - This reject cause indicates the reason for deregistration of UE3 from S-NSSAI-3. For example, the reject cause may indicate that UE3 has not requested a service or established a PDU session in the network slice identified by S-NSSAI-3 until the 'usage control timer' for UE3 has expired. The reject cause may be associated with S-NSSAI-3. The reject cause may indicate that UE3 has not used the network slice identified in S-NSSAI-3 until the 'usage control timer' for UE3 has expired. The reject cause may indicate the expiration of the 'usage control timer'.

[0159] 12. The AMF 70 receives an Nnwdaf_DeregistrationNotification message from the NWDAF 76. Upon receiving the Nnwdaf_DeregistrationNotification message, if the UE 3 is in connected mode, the AMF 70 may deregister the UE 3 for S-NSSAI-3 via a UE Configuration Update message, in which the AMF 70 removes the S-NSSAI-3 from the Allowed NSSAIs and adds the S-NSSAI-3 to the Rejected NSSAI for the UE 3. The AMF 70 may send a UE Configuration Update message. For example, the UE Configuration Update message may be represented as a UCU message. For example, the AMF 70 may include information in the UCU message to instruct the UE 3 to remove the S-NSSAI-3 from the Allowed NSSAIs and add the S-NSSAI-3 to the Rejected NSSAI. For example, when AMF70 sends a UCU message, AMF70 removes S-NSSAI-3 from the allowed NSSAI for UE3 stored in AMF70 and adds S-NSSAI-3 to the rejected NSSAI for UE3 stored in AMF70.

[0160] AMF70 also includes a rejection cause for S-NSSAI-3 in the UCU message, for example, a rejection cause set to "usage control timer expired" or "inactivity control timer expired", or any other indication of the rejection cause, to indicate that the network slice is rejected because it has not been used by UE3 until the usage control timer for UE3 for that network slice expires.

[0161] Alternatively, AMF70 may use the existing UE deregistration procedure by sending a deregistration request to UE3 that includes a network slice, e.g., S-NSSAI-3, where UE3 is denied registration, and a denial cause set to "Usage Control Timer Expired".

[0162] Upon receiving the Nnwdaf_DeregistrationNotification message, if the UE3 is in idle mode, the AMF70:

[0163] - After paging the UE 3 and connecting with the UE 3, the AMF 70 sends a UE CONFIGURATION UPDATE message to the UE 3 with a rejection S-NSSAI-3 and a rejection cause set to "Usage Control Timer Expired", or

[0164] - Stores the information in the Nnwdaf_NSAC_DeregistrationNotification message from the NWDAF 76 until the UE 3 returns to a connected state to the network, e.g., for service or PDU session establishment. When the UE 3 returns to a connected state to the network, the AMF 70 provides the UE 3 with a rejection S-NSSAI-3 and a rejection cause set to "Usage Control Timer Expired" via a UE Configuration Update message.

[0165] The AMF 70 may store information indicating whether the UE 3 is in a connected mode or an idle mode. The AMF 70 may receive information indicating whether the UE 3 is in a connected mode or an idle mode from another network node. The AMF 70 may determine whether the UE 3 is in a connected mode or an idle mode based on the information indicating whether the UE 3 is in a connected mode or an idle mode.

[0166] 13. If UE3 receives a registration rejection for a network slice, e.g., S-NSSAI-3, via a UE Configuration Update message or a UE Deregistration message with the rejection cause set to "Usage Control Timer Expired", UE3 removes the Rejected S-NSSAI-3 from the Allowed NSSAIs, and UE3 continues registration for S-NSSAI-1 and S-NSSAI-2. UE3 may add the Rejected S-NSSAI-3 to the Rejected NSSAIs.

[0167] 14. Optionally, UE3 may refresh its registration by triggering a new registration procedure for S-NSSAI-1 and S-NSSAI-2 according to the registration procedure in Non-Patent Document 3.

[0168] For example, a communications device capable of NWDAF 76 may receive a first message. The first message may include Single Network Slice Selection Assistance Information (S-NSSAI). After receiving the first message, the communications device may start a timer for the S-NSSAI. The timer may be set to a value associated with the S-NSSAI. The communications device may transmit a second message for Network Slice Admission Control (NSAC) if the timer expires, and a third message. The second message may include the S-NSSAI. The third message may include the S-NSSAI and a rejection cause indicating the expiration of the timer.

[0169] For example, a first core network device corresponding to the NWDAF 76 may receive a message related to management of a network slice from a second core network device corresponding to the NSACF 77. The first core network device may analyze data related to the network slice based on information from other core network devices corresponding to at least one of the second core network device, the AMF 70, and the SMF 71. After receiving the message, the first core network device may start a timer for the network slice. The first core network device may detect that the timer has expired. After detecting that the timer has expired, the first core network device may send a message to the second core network device indicating at least one of the expiration of the timer or that the network slice associated with the timer is not in use. The second core network device may manage network slice admission control.

[0170] For example, a first core network device corresponding to NWDAF76 may receive a message related to management of a network slice from a second core network device corresponding to NSACF77. The first core network device may analyze data related to the network slice based on information from other network devices corresponding to at least one of the second core network device, AMF70, and SMF71. After receiving the message, the first core network device may start a timer for the network slice. The first core network device may detect an operation related to the network slice. After detecting the operation, the first core network device may stop the timer. The second core network device may manage network slice admission control.

[0171] Based on the above, it is possible to solve the above problems, such as whether and how to improve the system to ensure network-controlled behavior of network slice usage, including UE registration and PDU session establishment.

[0172] <Modification 1 of the second example of the first aspect> In step 11 of Figure 2, the NWDAF 76 may include a network slice usage back-off timer in the Nnwdaf_NSAC_DeregistrationNotification message to the AMF 70. If the network slice usage back-off timer is included by the NWDAF 76, the AMF 70 relays the network slice usage back-off timer to the UE 3 in step 12. If the UE 3 receives a rejection for a network slice (e.g., S-NSSAI-3) with the rejection cause set to "usage control timer expired" and the network slice usage back-off timer set to "usage control timer expired," the UE 3 starts the network slice usage back-off timer, and the UE 3 does not request registration for the rejected network slice, e.g., S-NSSAI-3, while the network slice usage back-off timer for S-NSSAI-3 is running. The UE 3 may request registration for the rejected network slice, e.g., S-NSSAI-3, if the network slice usage back-off timer for S-NSSAI-3 expires. Cell reselection and registration area update by UE3 do not reset the network slice usage backoff timer in UE3. Upon PLMN change, UE3 resets the network slice usage backoff timer if it is still running. The network slice usage backoff timer may be associated with a rejected network slice (e.g., S-NSSAI-3).

[0173] <Modification 2 of the second example of the first aspect> If the number of UEs registered for S-NSSAI-3 reaches a threshold, e.g., the maximum number of UEs registered for S-NSSAI-3, the NWDAF 76 may trigger a Nnwdaf_NSAC_DeregistrationNotification message to the AMF 70. If the number of UEs registered for S-NSSAI-3 reaches a threshold, e.g., the maximum number of UEs registered for S-NSSAI-3, it may mean that the network slice identified by S-NSSAI-3 is overloaded. For example, this may be indicated from the NSACF 77 to the NWDAF 76 via an Nnsacf_MaxRegisteredUEs message that includes the S-NSSAI-3 or any other indication for a message from the NSACF 77 to the NWDAF 76 to indicate that the number of registered UEs for the network slice, e.g., S-NSSAI-3, has reached its maximum value. In this case, the reject cause in the Nnwdaf_NSAC_DeregistrationNotification message indicates that the maximum number of UEs registered for the network slice, e.g., S-NSSAI-3, has been reached. In step 12, AMF 70 communicates the rejected S-NSSAI-3 and a new rejection cause set to "the maximum number of UEs registered in the network slice has been reached" to UE 3, and UE 3 removes the rejected network slice, e.g., S-NSSAI-3, from the allowed NSSAI. The new rejection cause set to "the maximum number of UEs registered in the network slice has been reached" may indicate that the maximum number of UEs registered in the network slice, e.g., S-NSSAI-3, has been reached. In addition, the Nnwdaf_NSAC_DeregistrationNotification message may include a back-off timer parameter for the rejected network slice, e.g., S-NSSAI-3. If the back-off timer parameter is included in the UCU message or the deregistration request message by AMF 70, UE 3 starts a timer using the value provided in the back-off timer parameter, and UE 3 does not attempt another registration to the rejected network slice, e.g., S-NSSAI-3, while the timer is still running.UE3 may attempt another registration to the rejected network slice, e.g., S-NSSAI-3, if the timer expires.

[0174] <Modification 3 of the second example of the first aspect> If there is another network slice (e.g., S-NSSAI-4) supported by AMF 70 and UE 3 subscribes to another network slice (e.g., S-NSSAI-4) that can provide the same service as, a similar service to, or an alternative service to, the rejected S-NSSAI-3, then in step 12 of FIG. 2, AMF 70 may provide UE 3 with a substitute network slice for the rejected S-NSSAI-3. In that case, AMF 70 includes the substitute network slice (e.g., S-NSSAI-4) in the authorized NSSAI for UE 3 in step 12, and UE 3 becomes registered for S-NSSAI-1, S-NSSAI-2, and the substitute network slice (e.g., S-NSSAI-4). For example, AMF 70 may store information indicating the substitute network slice (e.g., S-NSSAI-4). For example, AMF70 may store information indicating a network slice to which UE3 is subscribed and which may provide the same, similar, or alternative service as the rejected S-NSSAI-3.

[0175] <Modification 4 of the second example of the first aspect> When UE3 releases the PDU session in S-NSSAI-1 and S-NSSAI-2 established in step 5, SMF71 contacts NWDAF76 for slice usage notification. For example, when SMF71 receives a notification from another node (e.g., UE3) regarding the release of the PDU session in S-NSSAI-1 and S-NSSAI-2, SMF71 may contact NWDAF76 for slice usage notification.

[0176] In this case, the NWDAF 76 restarts the usage control timers for S-NSSAI-1 and S-NSSAI-2 for the UE 3 when the associated PDU session is released.

[0177] <Modification 5 of the second example of the first aspect> In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter.

[0178] For example, the NSACF 77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control based on the inclusion of the S-NSSAI and usage control timer parameters.

[0179] If the NSACF 77 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without a usage control parameter in step 2, the NSACF 77 may send an Nnwdaf_SliceUsageControl message without a usage control parameter to the NWDAF 76 in step 3. The NWDAF 76 may then start usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 4, and the subsequent process may be performed according to the second example of the first aspect.

[0180] In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter and the usage control timer parameter.

[0181] For example, based on receiving an Nnsacf_NSAC_NumOfUEsUpdate_Request message, NSACF77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control.

[0182] For example, based on receiving a Nnwdaf_SliceUsageControl message, the NWDAF 76 may understand that the network slice identified by the S-NSSAI in the Nnwdaf_SliceUsageControl message is subject to usage control or inactivity control.

[0183] If the NSACF 77 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without usage control parameters and usage control timer parameters in step 2, the NSACF 77 may send an Nnwdaf_SliceUsageControl message without usage control parameters and usage control timer parameters to the NWDAF 76 in step 3. The NWDAF 76 may then start the usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 4, and the subsequent process may be performed according to the second example of the first aspect. In this case, the NWDAF 76 may configure the values ​​of the usage control timers based on the NWDAF 76's local configuration or an operator's policy stored in the NWDAF 76.

[0184] In another example, in step 2, if the NSACF 77 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without a usage control parameter and a usage control timer parameter, the NSACF 77 may configure the value of the usage control timer based on the local configuration of the NSACF 77 or an operator policy stored in the NSACF 77 and send an Nnwdaf_SliceUsageControl message to the NWDAF 76 including the value of the usage control timer.

[0185] <Modification 6 of the second example of the first aspect> If the NWDAF 76 detects that the S-NSSAI is in a congested state (e.g., the number of UEs registered to the S-NSSAI identifying the congested network slice has reached a threshold, e.g., the maximum number of UEs registered to S-NSSAI-3), the NWDAF 76 may send two messages, namely, an Nnwdaf_NSAC_DeregistrationRequest message (or an Nnwdaf_DeregistrationRequest message) and an Nnwdaf_NSAC_DeregistrationNotification message, to the NSACF 77 and the AMF 70, respectively. The S-NSSAI identifying the congested network slice may be referred to as a congested S-NSSAI. In this case, the NWDAF 76 sends two messages to multiple NSACFs 77, each message including the congested S-NSSAI and the registered UE IDs for the congested S-NSSAI, as well as a rejection cause indicating that the network slice is congested.

[0186] When NSACF77 (e.g., each of NSACF77) receives a Nnwdaf_NSAC_DeregistrationRequest message including multiple UE IDs, NSACF77 may then deregister all UEs indicated for the network slice indicated by the congested S-NSSAI and may reduce the number of UEs registered to the congested S-NSSAI by the number of UEs indicated for the congested S-NSSAI.

[0187] When AMF70 receives a Nnwdaf_NSAC_DeregistrationNotification message containing multiple UE IDs, AMF70 performs the UE configuration update procedure as described in step 12 for all UEs included in the received Nnwdaf_NSAC_DeregistrationNotification message with a rejection cause indicating that the network slice is congested.

[0188] <Modification 7 of the second example of the first aspect> The NWDAF 76 may not send a Nnwdaf_NSAC_DeregistrationNotification message (or a Nnwdaf_DeregistrationRequest message) to the AMF 70 as described in step 11. In this case, upon receiving the Nnwdaf_NSAC_DeregistrationRequest message (or a Nnwdaf_DeregistrationRequest message) at the NSACF 77, the NSACF 77 sends a Nnsacf_NSAC_DeregistrationNotification message to the associated AMF for all UEs included in the received Nnwdaf_NSAC_DeregistrationRequest message (or a Nnwdaf_DeregistrationRequest message) with a rejection cause indicating that the network slice is congested or the usage control timer has expired, as described in step 8 in the first example of the first aspect.

[0189] <Modification 8 of the second example of the first aspect> The NWDAF 76 may be another NSACF from the NSACF 77. The other NSACF may be in a PLMN or another HPLMN. In this case, the following message name changes apply: The Nnwdaf_SliceUsageControl message in steps 3 and 7 may be replaced by a Nnsacf_NSAC_NumOfUEsUpdate_Request message or other message for the NSACF service. The Nnwdaf_DeregistrationRequest message in step 10 can be replaced by a Nnsacf_DeregistrationRequest message or other message for the NSACF service. The Nnwdaf_DeregistrationNotification message in step 11 can be replaced by a Nnsacf_DeregistrationNotification message or other message for the NSACF service.

[0190] <Third Example of the First Aspect> A third example of the first aspect in Figure 3 discloses a mechanism that enables the network to deregister UE3 from the network slice or place the network slice in an inactive state when the network slice is not used for a long period of time, for example, when a PDU session is not established by UE3 in the network slice for a specific duration or when a PDU session is not active for a specific duration, when the registration of UE3 is controlled by NSACF7701 and the PDU session of UE3 is controlled by NSACF7702.

[0191] 1. The UE 3 registers with the AMF 70 for a network slice, for example, identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and supported by the network and the AMF 70 at the location of the UE 3. For example, the UE 3 may perform a registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 according to non-patent document 3.

[0192] 2. If the network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 comply with Network Slice Admission Control (NSAC), AMF 70 registers UE 3 with NSACF 7701 for each of these network slices for allocation control, i.e., to control the number of UEs registered in a network slice so that it does not exceed the maximum number of UEs allowed to register for that network slice. NSACF 7701 may control the number of UEs registered in a network slice so that it does not exceed the maximum number of UEs allowed to register for that network slice. AMF 70 may find out whether the network slice complies with NSAC by interacting with UDM 75 to obtain subscription information for UE 3 along with information about whether the network slice complies with NSAC. For example, AMF 70 may already have subscription information for UE 3 in the context of UE 3 within AMF 70. For example, AMF 70 may be configured with information about whether the network slice complies with NSAC.

[0193] If the requested network slices identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 and requested by UE 3 are subject to NSAC, AMF 70 registers UE 3 to these network slices by sending an Nnsacf_NSAC_NumOfUEsUpdate_Request message to NSACF 7701. To indicate to NSACF 7701 that the network slices are subject to usage control or inactivity control, AMF 70 includes in the message the identification information (e.g., UE-Id) of UE 3, S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 identifying the requested network slices, and a parameter called "usage control" set to on or "inactivity control" set to on, or any other indication of the parameter. "Usage control" set to on or "inactivity control" set to on may indicate that UE 3 will be deregistered from the network slice if the network slice is not used by UE 3 for a certain period of time.

[0194] "Usage control" or "inactivity control" to indicate to NSACF77 that the network slice is subject to usage control or inactivity control, or any other indication of a parameter, may be collectively referred to as "usage control" or "usage control" parameters.

[0195] For example, the "Usage Control" may be associated with the S-NSSAIs to which UE 3 registers. For example, the "Usage Control" set to ON may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0196] The AMF70 may also include a "usage control timer" parameter or an "inactivity control timer" parameter, or any other indication of a parameter, in the Nnsacf_NSAC_NumOfUEsUpdate_Request message to define the time or period during which the UE3 is deregistered from the network slice if the network slice is not used by the UE3, for example, if there is no service request or no PDU session is established by the UE3 in the network slice.

[0197] The "usage control timer" parameter or "inactivity control timer" parameter for determining the time or period during which UE3 is deregistered from the network slice if the network slice is not used by UE3, or any other indication of the parameter, may be collectively referred to as the "usage control timer" or "usage control timer" parameter.

[0198] For example, the AMF 70 may configure the "usage control timer" parameter based on a local configuration at the AMF 70 or a network operator policy within the AMF 70. Alternatively, the "usage control timer" parameter may be configured in the NSACF 7701, or the "usage control timer" parameter is based on a network operator policy within the NSACF 7701. For example, the AMF 70 or the NSACF 7701 may determine the value of the "usage control timer" parameter.

[0199] For example, the "Usage Control Timer" parameter may be associated with the S-NSSAI to which UE3 registers. For example, the "Usage Control Timer" may be associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be the same for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, or may be different for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The value of the "Usage Control Timer" parameter may be expressed as a value associated with S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3.

[0200] For example, AMF70 may send an Nnsacf_NSAC_NumOfUEsUpdate_Request message during the registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. For example, AMF70 may send a message related to the network slice to NSACF7701. For example, AMF70 may send a message related to the management of the network slice to NSACF7701. For example, AMF70 may send a message related to the management of the number of UEs registered in the network slice to NSACF7701.

[0201] 3. The NSACF 7701 receives the Nnsacf_NSAC_NumOfUEsUpdate_Request message from the AMF 70.

[0202] If the network slice to which UE3 registers is subject to usage control or inactivity control, for example, if the "usage control" parameter from AMF70 is set to on, NSACF7701 starts a timer that measures the time when the network slice is not being used by UE3, for example, the time when no service is requested or no PDU session is established by UE3 in the network slice, or no data is exchanged in an established PDU session. The timer may be referred to, for example, as a "usage control timer" or an "inactivity control timer," or any other indication of a timer. The "usage control timer" or an "inactivity control timer," or any other indication of a timer, may be collectively referred to as a "usage control timer."

[0203] The "Usage Control Timer" or "Inactivity Control Timer" may be set by the operator to a value configured in NSACF 7701. The "Usage Control Timer" or "Inactivity Control Timer" may be set to a value indicated by AMF 70 in the "Usage Control Timer" or "Inactivity Control Timer" parameter.

[0204] The NSACF 7701 executes a "usage control timer" for each network slice subject to usage control, e.g., a network slice for which the "usage control" parameter is set to on. For example, the NSACF 7701 executes a "usage control timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. The "usage control timer" may be controlled per UE by the NSACF 7701. For example, the NSACF 7701 may control a "usage control timer" for each UE identified by a UE-Id. For example, the NSACF 7701 may execute a "usage control timer" for at least one of S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 for UE 3.

[0205] 4. At some stage, UE 3 having authorized NSSAIs including S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, for example, UE 3 requests PDU session establishment in S-NSSAI-3. The PDU session in S-NSSAI-3 is registered with NSACF 7702 and specified for the number of PDU sessions per network slice allocation control according to section 4.2.11 of non-patent document 3. For example, NSACF 7702 may control the number of PDU sessions per network slice allocation control according to section 4.2.11 of non-patent document 3. For example, NSACF 7702 detects an operation related to a network slice (e.g., a network slice identified by S-NSSAI-3).

[0206] 5. NSACF 7702 notifies NSACF 7701 about the PDU session established in S-NSSAI-3 via an Nnsacf_SliceUsageNotify message. NSACF 7702 includes in the Nnsacf_SliceUsageNotify message the UE Id, a PDU-Id with a value set to on, and the network slice identification information on which the active PDU session exists.

[0207] For example, the UE-Id may be identification information of the UE 3.

[0208] For example, the PDU-Id may be an identification information of an active PDU session in the network slice.

[0209] The identification information of the active PDU session may be represented as active PDU session identification information.

[0210] For example, the PDU-Id may be an active PDU session identification information in the network slice.

[0211] For example, the PDU-Id may be an active PDU session identification in the network slice identified by the network slice identification.

[0212] For example, the PDU-Id may be an active PDU session identification in the network slice identified by S-NSSAI-3.

[0213] For example, a PDU-Id having a value set to on may mean that the PDU session identified by the PDU-Id is active in the network slice identified by the network slice identification information.

[0214] For example, a PDU-Id having a value set to on may mean that the PDU session identified by the PDU-Id is active in the network slice identified by S-NSSAI-3.

[0215] For example, the network slice identification information in which an active PDU session exists may be S-NSSAI-3. For example, if NSACF7702 receives a message indicating an operation related to the network slice identified by S-NSSAI-3, NSACF7702 may send a message to NSACF7701 indicating detection of an operation related to the network slice identified by S-NSSAI-3.

[0216] "PDU-Id with a value set to on" can be expressed as "PDU-Id=on".

[0217] The Nnsacf_SliceUsageNotify message may be represented as a message related to the establishment of a PDU session for S-NSSAI-3.

[0218] 6. NSACF 7701 receives an Nnsacf_SliceUsageNotify message from NSACF 7702. If NSACF 7701 has an active usage control timer running for UE 3 for S-NSSAI-3, NSACF 7701 stops the "usage control timer" for S-NSSAI-3. For example, if the Nnsacf_SliceUsageNotify message includes a PDU-Id with a value set to on and S-NSSAI-3, NSACF 7701 may determine that there is an active PDU session identified by the PDU-Id in the network slice identified by S-NSSAI-3. In this case, if NSACF 7701 started the usage control timer for S-NSSAI-3 in step 3, NSACF 7701 may stop the usage control timer for S-NSSAI-3. For example, when NSACF7701 receives a message from NSACF7702 indicating the detection of an operation related to the network slice identified by S-NSSAI-3, NSACF7701 stops the usage control timer for S-NSSAI-3 that was started in step 3.

[0219] 7. At some stage, for example, UE3 requests PDU session release in S-NSSAI-3. The PDU session in S-NSSAI-3 is deregistered in NSACF 7702 and is specified for the number of PDU sessions to be established in the network slice allocation control according to clause 4.2.11 of 3GPP TS 36.110. For example, UE3 requests to release the PDU session identified by the PDU-Id activated in the network slice identified by S-NSSAI-3.

[0220] 8. NSACF 7702 receives a notification from another network node (e.g., SMF 71) that a PDU session identified by the PDU-Id and activated in the network slice identified by S-NSSAI-3 is released. In this case, NSACF 7702 notifies NSACF 7701 about the release of the PDU session in S-NSSAI-3 via an Nnsacf_SliceUsageNotify message. NSACF 7702 includes the UE Id, the PDU-Id with a value set to off, and the network slice identification information for the released PDU session in the Nnsacf_SliceUsageNotify message.

[0221] For example, the UE-Id may be identification information of the UE 3.

[0222] For example, the PDU-Id may be an identification information of a release PDU session in a network slice.

[0223] The identification information of the release PDU session may be expressed as release PDU session identification information.

[0224] For example, the PDU-Id may be a release PDU session identification information in a network slice.

[0225] For example, the PDU-Id may be a release PDU session identification in a network slice identified by the network slice identification.

[0226] For example, the PDU-Id may be a release PDU session identification in the network slice identified by S-NSSAI-3.

[0227] For example, a PDU-Id having a value set to off may mean that the PDU session identified by the PDU-Id is released in the network slice identified by the network slice identification information.

[0228] For example, a PDU-Id having a value set to off may mean that the PDU session identified by the PDU-Id is released in the network slice identified by S-NSSAI-3.

[0229] For example, the network slice identification information for the release PDU session may be the network slice identification information of the network slice in which the active PDU session existed.

[0230] For example, the network slice identification information for the solution PDU session may be S-NSSAI-3.

[0231] A "PDU-Id with a value set to off" can be expressed as "PDU-Id=off".

[0232] The Nnsacf_SliceUsageNotify message in step 8 may be represented as a message related to the release of the PDU session for S-NSSAI-3.

[0233] 9. If NSACF 7701 has an active usage control timer for UE 3 for S-NSSAI-3, NSACF 7701 restarts the "usage control timer" for S-NSSAI-3. For example, if the Nnsacf_SliceUsageNotify message includes a PDU-Id with a value set to off and S-NSSAI-3, NSACF 7701 may determine that an active PDU session identified by the PDU-Id in the network slice identified by S-NSSAI-3 is to be released. In this case, if NSACF 7701 stopped the usage control timer for S-NSSAI-3 in step 6, NSACF 7701 may restart the usage control timer for S-NSSAI-3. When restarting the usage control timer, NSACF 7701 may restart the usage control timer from the beginning or from the middle. For example, if the usage control timer is set to 100 seconds and the usage control timer has already measured 10 seconds, and NSACF 7701 stops the usage control timer in step 6, NSACF 7701 may restart the usage control timer with a value set to 100 seconds, or may restart the usage control timer with a value set to 90 seconds.

[0234] 10. After a while, the "usage control timer" for S-NSSAI-3 for UE3 expires because no action has been signaled for S-NSSAI-3 by UE3 for some time. For example, the "usage control timer" for UE3 for S-NSSAI-3 expires because UE3 has not used S-NSSAI-3, i.e., UE3 has not requested a service or established a PDU session in S-NSSAI-3 for some time. For example, NSACF7701 may detect that the usage control timer for S-NSSAI-3 for UE3 has expired.

[0235] 11. Upon expiration of the "usage control timer" for a network slice, for example, S-NSSAI-3, the NSACF 7701 sends an Nnsacf_SliceUsageNotification message to the AMF 70, including the UE_Id, S-NSSAI-3, and a state parameter set to inactive. The Nnsacf_SliceUsageNotification message may include a cause parameter set to usage control timer expiration. The NSACF 7701 may include the following parameters:

[0236] -UE-Id (UE-Id) - Identification information of the UE3.

[0237] - S-NSSAI-3 (S-NSSAI-3) - Network Slice Identification Information when the "Usage Control Timer" expires.

[0238] Status parameter—NSACF7701 may include a status parameter to indicate whether the notified network slice, e.g., S-NSSAI-3, has been inactive for a while, e.g., until the expiration of a usage control timer for the network slice. For example, a status parameter set to inactive may mean that the network slice identified by the network slice identity in the Nnsacf_SliceUsageNotification message has been inactive until the expiration of a usage control timer for the network slice. For example, if the Nnsacf_SliceUsageNotification message includes S-NSSAI-3 as the network slice identity, a status parameter set to inactive may mean that the network slice identified by S-NSSAI-3 has been inactive or is not being used by UE3 until the expiration of a usage control timer for the network slice. A status parameter set to inactive may be represented as “status=inactive.”

[0239] Cause parameter—Optionally, the NSACF 7701 may also include a cause parameter to indicate the reason why the network slice is indicated as inactive, for example, usage control timer expiration. For example, a cause parameter set to “usage control timer expiration” may mean that the network slice is inactive because the usage control timer for the network slice has expired. A cause parameter set to “usage control timer expiration” may be represented as cause=“usage control timer expiration”.

[0240] For example, after step 10, NSACF 7701 may send a message to AMF 70 indicating that the network slice (e.g., the network slice identified by S-NSSAI-3) is not in use.

[0241] 12. When the AMF 70 is notified by the NSACF 7701 to indicate that the notified network slice has not been used or has become inactive for some time, for example, for an S-NSSAI-3 that is inactive with a cause set to usage control timer expiration or any other indication of the cause or state (for example, when the AMF 70 receives an Nnsacf_SliceUsageNotification message including the UE-Id, S-NSSAI-3, and a state parameter that is inactive, or when the AMF 70 receives an Nnsacf_SliceUsageNotification message including the UE-Id, S-NSSAI-3, a state parameter that is inactive, and a cause parameter that is set to "usage control timer expiration"), the AMF 70 may follow one of the following behaviors:

[0242] -AMF70 may deregister UE3 from a network slice that UE3 has not used for some time, for example, S-NSSAI-3, by removing S-NSSAI-3 from the allowed NSSAIs for UE3 and adding S-NSSAI-3 to the denied NSSAI, as described in steps 11 and 12 in the second example of the first aspect.

[0243] The AMF 70 may keep the UE 3 registered with a network slice reported as inactive or unused, for example, S-NSSAI-3, and mark the network slice identified by S-NSSAI-3 as inactive or unused in the context of the UE 3 within the AMF 70. The AMF 70 may mark the S-NSSAI-3 as inactive or unused when the S-NSSAI-3 is inactive or unused for a specific period of time. S AMF70 may deregister the network slice, e.g., S-NSSAI-3, from NSACF7701 according to section 4.2.11 of non-patent document 3 so that AI-3 is not counted for allocation control. As soon as an inactive network slice, e.g., S-NSSAI-3, is used again by UE3, e.g., as soon as a PDU session is established in S-NSSAI-3, AMF70 re-registers the network slice with NSACF7701 for allocation control. For example, if AMF70 can determine that an inactive network slice, e.g., S-NSSAI-3, is used again by UE3, AMF70 can instruct NSACF7701 to count UE3 for allocation control. For example, if AMF70 receives information from another network node (e.g., SMF71 or UE3) indicating that an inactive network slice, e.g., S-NSSAI-3, will be used again by UE3, AMF70 may determine that the inactive network slice, e.g., S-NSSAI-3, will be used again by UE3.

[0244] The Nnsacf_SliceUsageNotification message may be represented as a message that removes S-NSSAI-3 from the allowed NSSAIs, the Nnsacf_SliceUsageNotification message may be represented as a message that adds S-NSSAI-3 to the rejected NSSAI, or the Nnsacf_SliceUsageNotification message may be represented as a message that deregisters S-NSSAI-3.

[0245] For example, a communications device compliant with NSACF 7701 may receive a first message. The first message may include Single Network Slice Selection Assistance Information (S-NSSAI). After receiving the first message, the communications device may start a timer for the S-NSSAI. The timer may be set to a value associated with the S-NSSAI. After starting the timer, the communications device may receive a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI. After receiving the second message, the communications device may stop the timer. After stopping the timer, the communications device may receive a third message related to release of the PDU session. After receiving the third message, the communications device may start the timer. The communications device may transmit a fourth message if the timer expires. The fourth message may be for removing the S-NSSAI from the authorized Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI.

[0246] For example, a first network slice control function node corresponding to the NSACF 7701 may receive a message related to management of a network slice from a core network device corresponding to the AMF 70. After receiving the message, the first network slice control function node may start a timer for the network slice. The first network slice control function node may detect that the timer has expired. After detecting that the timer has expired, the first network slice control function node may send a message to the core network device indicating at least one of the expiration of the time or that the network slice associated with the timer is not in use.

[0247] For example, a first network slice control function node corresponding to NSACF 7701 may receive a message related to management of a network slice from a core network device corresponding to AMF 70. After receiving the message, the first network slice control function node may start a timer for the network slice. The first network slice control function node may receive a message detecting an operation related to the network slice from a second network slice control function node corresponding to NSACF 7702. After receiving the message, the first network slice control function node may stop the timer.

[0248] Based on the above, it is possible to solve the above problems, such as whether and how to improve the system to ensure network-controlled behavior of network slice usage, including UE registration and PDU session establishment.

[0249] <Modification 1 of the third example of the first aspect> In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter.

[0250] For example, the NSACF 7701 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control based on the inclusion of the S-NSSAI and usage control timer parameters.

[0251] In step 2, if NSACF7701 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without usage control parameters, NSACF7701 may start usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 3, and the subsequent process may be performed according to the third example of the first aspect.

[0252] In step 2, the Nnsacf_NSAC_NumOfUEsUpdate_Request message may not include the usage control parameter and the usage control timer parameter.

[0253] For example, based on receiving an Nnsacf_NSAC_NumOfUEsUpdate_Request message, the NSACF 7701 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfUEsUpdate_Request message is subject to usage control or inactivity control.

[0254] If in step 2 the NSACF 7701 receives an Nnsacf_NSAC_NumOfUEsUpdate_Request message without usage control parameters and usage control timer parameters, the NSACF 7701 may start the usage control timers for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 in step 3, and the subsequent process may be performed according to the third example of the first aspect. In this case, the NSACF 7701 may configure the values ​​of the usage control timers based on the NSACF 7701's local configuration or an operator's policy stored in the NSACF 7701.

[0255] <Fourth Example of the First Aspect> The fourth example of the first aspect in Figure 4 discloses a mechanism that enables the network to release a PDU session associated with a network slice via NSACF77 when there is no user plane activity for an extended period of time.

[0256] 1. The UE 3 registers with the AMF 70 for a network slice, for example, identified by S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and supported by the network and the AMF 70 at the location of the UE 3. For example, the UE 3 may perform a registration procedure for S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 according to non-patent document 3.

[0257] 2. At some stage, UE3 having an authorized NSSAI including S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, for example, UE3 requests service or PDU session establishment in S-NSSAI-1.

[0258] 3. The SMF 71 registers the PDU session established in S-NSSAI-1 with the NSACF 77 for allocation control of the maximum number of PDU sessions by sending a Nnsacf_NSAC_NumOfPDUsUpdate_Request message containing the UE-Id, S-NSSAI-1, the usage control set to on, and the usage session control timer. The Nnsacf_NSAC_NumOfPDUsUpdate_Request message may contain a PDU session ID identifying the PDU session established in step 2.

[0259] The UE-Id may be the identification information of the UE 3.

[0260] Usage control set to on may indicate to NSACF77 that the network slice is subject to usage control or inactive control. In this case, usage control set to on may indicate to NSACF77 that S-NSSAI-1 (or the network slice identified by S-NSSAI-1) is subject to usage control or inactive control. "Usage control set to on" may be expressed as "usage control = on". Usage control may be expressed as a usage control parameter.

[0261] The usage session control timer may define a time or period during which UE3 is deregistered from the network slice when the network slice is not used by UE3, e.g., when there is no service request or no PDU session is established by UE3 in the network slice. In this case, the usage session control timer may define a time or period during which UE3 is deregistered from the network slice when the network slice identified by S-NSSAI-1 is not used by UE3, e.g., when there is no service request or no PDU session is established by UE3 in the network slice.

[0262] For example, the SMF 71 may configure the usage session control timer based on local configuration in the SMF 71 or network operator policy within the SMF 71.

[0263] The usage session control timer may be expressed as a usage session control timer parameter. For example, the SMF 71 may send a message related to the management of the network slice to the NSACF 77 to initiate control of the number of sessions (e.g., PDU sessions) by the NSACF 77 based on the usage session control timer.

[0264] 4. Upon receiving the Nnsacf_NSAC_NumOfPDUsUpdate_Request message, the NSACF 77 performs allocation control for PDU sessions according to section 4.2.11 of Non-Patent Document 3.

[0265] 5. If the Nnsacf_NSAC_NumOfPDUsUpdate_Request message contains usage control set to on, the NSACF 77 sends an Nsmf_EventExposure_Subscribe request message to the SMF 71 containing the UE_Id, the PDU session ID, the event ID to be set for the usage session timer, and the timer value.

[0266] The UE-Id may be the identification information of the UE 3.

[0267] The PDU session ID may be identification information of a PDU session. The PDU session ID may be identification information of a PDU session established in the network slice identified by S-NSSAI-1.

[0268] The PDU session ID may be the same as the one received in step 3.

[0269] The event ID may identify the type of event to which you are subscribing.

[0270] The event ID set in the usage session timer may indicate that the network slice is subject to usage control or inactivity control. In this case, the event ID set in the usage session timer may indicate that S-NSSAI-1 (or the network slice identified by S-NSSAI-1) is subject to usage control or inactivity control.

[0271] For example, the event ID set in the usage session timer may indicate that UE 3 is deregistered from the network slice when the network slice is not used by UE 3, e.g., when there is no service request or no PDU session is established by UE 3 in the network slice. In this case, the event ID set in the usage session timer may indicate that UE 3 is deregistered from the network slice identified by S-NSSAI-1 when the network slice is not used by UE 3, e.g., when there is no service request or no PDU session is established by UE 3 in the network slice.

[0272] The "event ID set in the usage session timer" can be expressed as "event ID=usage session timer".

[0273] The timer value may be configured by the NSACF 77 based on local configuration at the NSACF 77, or may be the same as the value of the usage session control timer received in the Nnsacf_NSAC_NumOfPDUsUpdate_Request message in step 3. The timer value may be associated with the PDU session ID. For example, the NSACF 77 sends a message to the SMF 71 indicating control of the number of sessions (e.g., PDU sessions) by the NSACF 77 based on the usage session control timer being or being started.

[0274] 6. Upon receiving the Nsmf_EventExposure_Subscribe request message from the NSACF 77, the SMF 71 performs the Nsmf_EventExposure service in the UPF 72 to monitor user plane activity for the PDU session as described in section 5.2.8.3 of 3GPP TS 235.1106. For example, the SMF 71 may determine whether it detects user plane activity for the PDU session identified by the PDU session ID received in step 5 within the period specified by the timer value received in step 5. For example, the SMF 71 may determine whether it detects user plane activity for each UE identified by the UE-Id within the period specified by the timer value for the PDU session identified by the PDU session ID. When the SMF 71 determines whether it detects user plane activity within the period specified by the timer value, the SMF 71 may use a timer that is set to the period specified by the timer value. For example, SMF 71 may monitor user plane operations after receiving a message indicating control of the number of sessions (e.g., PDU sessions) by NSACF 77 based on the usage session control timer being started or being started in step 5.

[0275] 7. If the SMF 71 detects that there is no user plane activity within the period specified by the timer value in step 5, the SMF 71 sends an Nsmf_EventExposure_Notify message to the NSACF 77 indicating that user inactivity on the specified PDU session has been detected.

[0276] For example, if SMF71 detects that there is no user plane activity for a PDU session identified by a PDU session ID within a period specified by a timer value, SMF71 may send an Nsmf_EventExposure_Notify message to NSACF77 indicating that user inactivity in the PDU session has been detected.

[0277] The Nsmf_EventExposure_Notify message may include the UE-Id and the PDU Session ID.

[0278] The UE-Id may be the identification information of the UE 3. The UE-Id may be the same as that received in step 5.

[0279] The PDU session ID may be the identification information of the PDU session. The PDU session ID may be the identification information of the PDU session established in the network slice identified by S-NSSAI-1. The PDU session ID may be the same as the one received in step 5.

[0280] For example, SMF71 may send an Nsmf_EventExposure_Notify message if there is no user plane activity for a PDU session until the SMF71 timer expires.

[0281] The Nsmf_EventExposure_Notify message may indicate that there is no user plane operation for the PDU session.

[0282] The Nsmf_EventExposure_Notify message may include information indicating no user plane activity for the PDU session. The information may be expressed as information indicating "user plane inactivity detected." For example, the SMF 71 sends a message to the NSACF 77 indicating that no user plane activity is detected based on the monitoring or the results of the monitoring in step 6.

[0283] 8. Upon receiving the Nsmf_EventExposure_Notify message in step 7, the NSACF 77 sends an Nnsacf_NSAC_ReleaseNotification message to the SMF 71 containing the UE_Id, S-NSSAI-1, and a release cause set to Usage Session Control Timer Expiration.

[0284] The UE-Id may be the identification information of the UE 3. The UE-Id may be the same as that received in step 7.

[0285] The Nsmf_EventExposure_Notify message may include network slice identification information that identifies a network slice in which there is no user plane activity within a period specified by the timer value. In this case, the Nsmf_EventExposure_Notify message may include S-NSSAI-1.

[0286] The release cause may indicate the reason why a PDU session established in a network slice is released.

[0287] For example, if NSACF 77 receives an Nsmf_EventExposure_Notify message indicating that user inactivity in a specified PDU session has been detected, NSACF 77 may set the release cause to Usage Session Control Timer Expiration. A release cause set to Usage Session Control Timer Expiration may mean that a PDU session established in the network slice is released due to a lack of user plane activity within a period specified by the timer value.

[0288] For example, if NSACF77 receives an Nsmf_EventExposure_Notify message indicating that user inactivity has been detected in a PDU session in a network slice identified by S-NSSAI-1, NSACF77 may set the release cause for S-NSSAI-1 to Usage Session Control Timer Expiration.

[0289] The release cause may be associated with the PDU session ID received in step 7.

[0290] The "release cause set for usage session control timer expiration" may be expressed as "release cause = usage session control timer expiration." For example, the SMF 71 may receive a message from the NSACF 77 indicating at least one of the usage session control timer expiration and the PDU session not being in an active state.

[0291] 9. Upon receiving the Nnsacf_NSAC_ReleaseNotification message in step 8, SMF 71 initiates the network-request PDU session release procedure as described in clause 4.3.4.2 of 3GPP TS 36.3144. As a result, the PDU session allocation control for S-NSSAI1 is performed between SMF 71 and NSACF 77, i.e., the number of PDU sessions for S-NSSAI1 is reduced in NSACF 77 by the network-request PDU session release procedure performed in step 9.

[0292] For example, in step 9, SMF71 may initiate a Network Request PDU Session Release procedure for S-NSSAI-1.

[0293] For example, in step 9, SMF71 may initiate a network request PDU session release procedure for the PDU session identified by the PDU session ID sent in step 7.

[0294] For example, if the Nnsacf_NSAC_ReleaseNotification message includes a release cause with a PDU session ID, SMF71 may initiate a network requested PDU session release procedure for the PDU session identified by the PDU session ID.

[0295] Upon receiving the Nsmf_EventExposure_Notify message in step 7, NSACF77 may reduce the number of PDU sessions established in the network slice for PDU session allocation control. In this case, NSACF77 may reduce by one the number of PDU sessions established in the network slice identified by S-NSSAI-1.

[0296] The Nnsacf_NSAC_ReleaseNotification message may be represented as a message that performs a network request PDU session release procedure.

[0297] The Nnsacf_NSAC_ReleaseNotification message may be represented as a message that performs a procedure to release a PDU session.

[0298] For example, a communication device supporting SMF71 may send a first message. The first message may include Single Network Slice Selection Assistance Information (S-NSSAI). The communication device may receive a second message. The second message may include identification information of a Protocol Data Unit (PDU) session. After receiving the second message, the communication device may start a timer. If there is no user plane operation for the PDU session until the timer expires, the communication device may send a third message. The third message may indicate that there is no user plane operation for the PDU session. After sending the third message, the communication device may receive a fourth message. After receiving the fourth message, the communication device may perform a procedure to release the PDU session.

[0299] For example, a communications device capable of NSACF 77 may receive a first message. The first message may include Single Network Slice Selection Assistance Information (S-NSSAI). The communications device may transmit a second message. The second message may include identification information for a Protocol Data Unit (PDU) session. After transmitting the second message, the communications device may receive a third message. The third message may indicate no user plane operation for the PDU session. After receiving the third message, the communications device may transmit a fourth message. The fourth message may be for performing a procedure to release the PDU session.

[0300] For example, a first core network device corresponding to the SMF 71 may send first information related to management of network slices to a second core network device corresponding to the NSACF 77 to start controlling the number of sessions based on a timer. The first core network device may receive second information from the second core network device indicating that the control will be started. After receiving the second information, the first core network device may monitor user plane operations related to the sessions. The first core network device may send third information to the second core network device indicating that no user plane operations are detected based on the monitoring. The first core network device may receive fourth information from the second core network device indicating at least one of the timer expiring or the session not being active within a period specified by the timer.

[0301] For example, a first core network device corresponding to the NSACF may receive first information related to management of a network slice from a second core network device corresponding to the SMF 71. After receiving the first information, the first core network device may start a timer for the network slice. The first core network device may send second information to the second core network device indicating that management will be initiated to start monitoring of user plane operations related to the session. The first core network device may receive third information from the second core network device indicating that no user plane operations are detected based on the monitoring. The first core network device may send fourth information to the second core network device indicating at least one of the expiration of the timer or the inactivity of the session within a period specified by the timer.

[0302] Based on the above, it is possible to solve the above problems, such as whether and how to improve the system to ensure network-controlled behavior of network slice usage, including UE registration and PDU session establishment.

[0303] <Modification 1 of the fourth example of the first aspect> If SMF 71 simply performs usage session control timer processing, steps 5, 7, and 8 are not performed. The timer value used in step 6 may be set based on local configuration in SMF 71 or based on operator policy in SMF 71.

[0304] If the SMF 71 detects that there is no user plane activity for the period specified by the timer value, step 9 is performed to release the PDU session associated with S-NSSAI1.

[0305] For example, if SMF71 detects that there is no user plane activity within the period specified by the timer value, SMF71 performs procedures to release the PDU session associated with the PDU session ID sent in step 3.

[0306] <Modification 2 of the fourth example of the first aspect> In step 3, the Nnsacf_NSAC_NumOfPDUsUpdate_Request message may not include a usage control parameter.

[0307] For example, the NSACF 77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfPDUsUpdate_Request message is subject to usage control or inactivity control based on the inclusion of the S-NSSAI and usage session control timer parameters.

[0308] In step 3, if the NSACF 77 receives an Nnsacf_NSAC_NumOfPDUsUpdate_Request message without a usage control parameter, the NSACF 77 may perform the process in step 4 and send an Nsmf_EventExposure_Subscribe request message with or without an event ID to the SMF 71 in step 5.

[0309] Then, SMF 71 may perform the process of step 6, and the subsequent process may be performed according to the fourth example of the first embodiment.

[0310] In step 3, the Nnsacf_NSAC_NumOfPDUsUpdate_Request message may not include the usage control parameter and the usage session control timer parameter.

[0311] For example, based on receiving an Nnsacf_NSAC_NumOfPDUsUpdate_Request message, NSACF77 may understand that the network slice identified by the S-NSSAI in the Nnsacf_NSAC_NumOfPDUsUpdate_Request message is subject to usage control or inactivity control.

[0312] In step 3, if the NSACF 77 receives an Nnsacf_NSAC_NumOfPDUsUpdate_Request message without the usage control parameters and usage session control timer parameters, the NSACF 77 may perform the process in step 4 and send an Nsmf_EventExposure_Subscribe request message with or without an event ID to the SMF 71 in step 5.

[0313] If the Nnsacf_NSAC_NumOfPDUsUpdate_Request message does not include a usage session control timer parameter, the NSACF 77 may configure a timer value based on the NSACF 77's local configuration or an operator's policy stored in the NSACF 77 and send the timer value via the Nsmf_EventExposure_Subscribe request message.

[0314] Then, SMF 71 may perform the process of step 6, and the subsequent process may be performed according to the fourth example of the first embodiment.

[0315] In another example, if the Nnsacf_NSAC_NumOfPDUsUpdate_Request message does not include a usage session control timer parameter, the NSACF 77 may not include a timer value in the Nsmf_EventExposure_Subscribe request message. In this case, the SMF 71 may configure the timer value based on the local configuration of the SMF 71 or an operator policy stored in the SMF 71. The SMF 71 may then perform the process of step 6, and the subsequent process may be performed according to the fourth example of the first aspect.

[0316] <System Overview> FIG. 5 shows a schematic diagram of a mobile (cellular or wireless) telecommunications system 1 to which the above aspects are applicable.

[0317] The telecommunications system 1 represents an overview of a system capable of end-to-end communication, e.g., UEs 3 (or user equipment, "mobile devices" 3) communicating with other UEs 3 or service servers within a data network 20 via respective (R)AN nodes 5 and a core network 7.

[0318] 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) technology as defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0319] 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 to each other to form the (R)AN node 5 by employing an architecture such as that defined by the Open RAN (O-RAN) Alliance, where the above units are referred to as the O-RU, O-DU, and O-CU, respectively.

[0320] The (R)AN node 5 may be separated into control plane functions and user plane functions. Furthermore, multiple user plane functions may be allocated to support communications. In some aspects, user traffic may be distributed across multiple user plane functions, with user traffic in each user plane function being aggregated at both the UE 3 and the (R)AN node 5. This separated architecture may be referred to as "dual connectivity" or "multi-connectivity."

[0321] The (R)AN node 5 may also support communications using satellite access. In some aspects, the (R)AN node 5 may support satellite access and terrestrial access.

[0322] 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).

[0323] 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, among other functions, control plane functions and user plane 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).

[0324] 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.

[0325] 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).

[0326] As is known, as a UE 3 moves around the geographic area covered by the telecommunications system 1, the UE 3 may move in and out of areas (i.e., radio cells) served by (R)AN nodes 5. To keep track of the UE 3 and facilitate movement between 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.

[0327] The core network 7 also includes, among other things, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, an Authentication Server Function (AUSF) 74, a Unified Data Management (UDM) 75, 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.

[0328] The UE 3 and each serving (R)AN node 5 are connected via an appropriate air interface (e.g., a 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 (e.g., a so-called "Xn" interface and / or the like). Each (R)AN node 5 is also connected to nodes in the core network 7 (e.g., so-called core network nodes) via appropriate interfaces (e.g., a so-called "N2" / "N3" interface 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 a PLMN. If the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), IP Multimedia Subsystem (IMS) services may be provided by that data network 20. The UE 3 may be connected to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or unstructured data types.

[0329] The "Uu" interface may include a control plane of the Uu interface and a user plane of the Uu interface.

[0330] 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 layered structure with SDAP, PDCP, RLC, and MAC sublayers over the physical connection.

[0331] 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 depending on the physical connection.

[0332] For example, the following messages are communicated in the RRC layer to support AS signaling:

[0333] - RRC Setup Request message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup Request message: --establishmentCause and ue-Identity. The ue-Identity may have the value of ng-5G-S-TMSI-Part1 or a random value.

[0334] RRC Setup Message: This message is sent from the (R)AN node 5 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup message: --Master cell group (masterCellGroup) and radio bearer configuration (radioBearerConfig)

[0335] - RRC Setup Complete message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup Complete message: --guami type (guami-Type), iab node indication (iab-NodeIndication), idle measurement available (idleMeasAvailable), mobility state (mobilityState), ng-5G-S-TMSI-Part2 (ng-5G-S-TMSI-Part2), registered AMF (registeredAMF), selected PLMN identity (selectedPLMN-Identity)

[0336] The UE 3 and the AMF 70 are connected via an appropriate 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 on the N1 interface:

[0337] Registration Request Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the registration request message: --5GS registration type, ngKSI, 5GS mobile identity, Non-current native NAS key set identifier, 5GMM capability, UE security capability, Requested NSSAI, Last visited registered TAI, S1 UE network capability, Uplink data status, PDU session status, MICO indication, UE status, Additional GUTI, Allowed PDU session status, UE's usage setting, Requested DRX parameters, EPS NAS message container, LADN indication, Payload container type, Payload container container, Network slicing indication, 5GS update type, Mobile station classmark 2, Supported codecs, NAS message container, EPS bearer context status, Requested extended DRX parameters, T3324 value, UE radio capability IDID), Requested mapped NSSAI, Additional information requested, Requested WUS assistance information, N5GC indication, and Requested NB-N1 mode DRX parameters.

[0338] Registration Accept Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be 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 valuevalue, T3324 value, UE radio capability ID, UE radio capability ID deletion indication, Pending NSSAI, Ciphering key data, CAG information list, Truncated 5G-S-TMSI configuration, Negotiated WUS assistance information, Negotiated NB-N1 mode DRX parameters, and Extended rejected NSSAI.

[0339] 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.

[0340] -Authentication Request Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the Authentication Request message: --ngKSI, ABBA, Authentication parameter RAND (5G authentication challenge), Authentication parameter AUTN (5G authentication challenge), and EAP message.

[0341] Authentication Response Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the authentication response message: Authentication response message identity, authentication response parameters, and EAP message.

[0342] -Authentication Result Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the Authentication Result Message: --ngKSI, EAP message, and ABBA.

[0343] Authentication Failure Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the Authentication Failure Message: --Authentication failure message identity, 5GMM cause, and authentication failure parameter.

[0344] -Authentication Rejection Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the authentication rejection message: --EAP message.

[0345] - Service Request Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, 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.

[0346] - Service Authorization Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the Service Authorization Message: --PDU session status, PDU session reactivation result, PDU session reactivation result error cause, EAP message, and T3448 value.

[0347] - Service Rejection Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the Service Rejection Message: --5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list.

[0348] Configuration Update Command Message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be 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 indication indication, 5GS registration result, Truncated 5G-S-TMSI configuration, Additional configuration indication, and Extended rejected NSSAI.

[0349] Configuration Update Complete message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be present together in the configuration update complete message: --Configuration update complete message identity.

[0350] <User equipment (UE)> FIG. 6 is a block diagram illustrating the main components of a mobile device 3 (UE 3). As shown, the UE 3 includes a transceiver circuit 31 operable to transmit signals to and receive signals from a connection node via one or more antennas 32. The UE 3 may also include a user interface 34 for inputting and outputting information from an external device. Although not necessarily illustrated, the UE 3 may have all the usual functions of a conventional mobile device, which may be provided by any one or any combination of hardware, software, and firmware, as needed. For example, the software may be pre-installed in memory and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The controller 33 controls the operation of the UE 3 in accordance with software stored in the memory 36. The software includes, among other things, an operating system 361 and a communication control module 362 having at least a transceiver control module 3621. The communications control module 362 (using its transceiver control module 3621) is responsible for handling (generating / sending / receiving) signaling and uplink / downlink data packets between the UE 3 and other nodes, such as the (R)AN node 5 and the AMF 70. Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for the UE 3). The controller 33 interacts with one or more Universal Subscriber Identity Modules (USIMs) 35. In the case of multiple USIMs 35, the controller 33 may activate only one USIM 35 or may activate multiple USIMs 35 simultaneously.

[0351] 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).

[0352] UE3 may be, for example, an item of production or manufacturing equipment and / or an item of energy-related machinery (e.g., equipment or machinery 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, metalworking machinery, manipulators, robots and / or application systems thereof, tools, molds or dies, rolls, conveying equipment, lifting equipment, material handling equipment, textile machinery, sewing machinery, printing machinery and / or related machinery, paper converting machinery, 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).

[0353] UE 3 may be, for example, an item of transportation equipment (e.g., vehicles, automobiles, motorcycles, bicycles, trains, buses, carts, rickshaws, ships and other watercraft, aircraft, rockets, satellites, drones, balloons, etc.).

[0354] The 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.).

[0355] 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 device, a consumer electronic device and appliance (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.).

[0356] 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.).

[0357] The 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 wall clock, laboratory equipment, optical equipment, medical equipment and / or systems, a weapon, an item of cutlery, a hand tool, or the like.

[0358] 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 measuring machine)).

[0359] 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)."

[0360] 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 autonomous 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 idle for long periods of time. IoT devices may be implemented as part of (generally) stationary equipment. IoT devices may also be incorporated into non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0361] 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, whether such communication device is controlled by human input or by software instructions stored in memory.

[0362] It will be appreciated that an IoT device is sometimes 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.

[0363] 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).

[0364] The UE3 may be a car, a connected car, an autonomous vehicle, a vehicle 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).

[0365] <(R)AN node> FIG. 7 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, a base station for Beyond 5G, or a base station for 6G). As shown, the (R)AN node 5 includes transceiver circuitry 51 operable to transmit signals to and receive signals from connected UEs 3 via one or more antennas 52, and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 53. A controller 54 controls operation of the (R)AN node 5 according to software stored in memory 55. For example, the software may be pre-installed in the memory and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 551 and a communications control module 552 having at least a transceiver control module 5521.

[0366] The communication control module 552 is responsible for processing (generating / sending / receiving) signaling between the (R)AN node 5 and other nodes such as the UE 3, another (R)AN node 5, the AMF 70, and the UPF 72 (using its transceiver control sub-module), either directly or indirectly. The signaling may include, for example, properly formatted signaling messages related to the radio connection and connection with the core network 7 for a specific UE 3, particularly those related to connection establishment and maintenance, such as RRC connection establishment messages and other RRC messages, NG Application Protocol (NGAP) messages (i.e., messages at the N2 reference point), Xn Application Protocol (XnAP) messages (i.e., messages at the Xn reference point), etc. Such signaling may also include, in the case of transmission, for example, broadcast information (such as master information and system information).

[0367] When implemented, the controller 54 is also configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0368] (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).

[0369] <System Overview of (R)AN Node 5 Based on O-RAN Architecture> Figure 8 schematically shows the (R)AN node 5 based on the O-RAN architecture to which the (R)AN node 5 aspect is applicable.

[0370] 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 with the DU 61 as a combined / combined unit, and the DU 61 may be combined with the CU 62 as another combined / combined unit. Any functionality described for a unit (e.g., one of the RU 60, DU 61, and CU 62) may be implemented in the combined / combined unit. 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 an appropriate interface (such as a so-called "E1" interface and / or the like).

[0371] The UE 3 and each serving RU 60 are connected via an appropriate air interface (e.g., a so-called "Uu" interface and / or the like). Each RU 60 is connected to a DU 61 via an appropriate 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 an appropriate 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 an appropriate 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 an appropriate interface (such as a so-called "N3" interface and / or the like).

[0372] Depending on the functionality split between the RU 60, DU 61, and CU 62, each unit provides a portion of the functionality provided by the (R)AN node 5. For example, the RU 60 may provide functionality for communicating with the UE 3 over the air interface, the DU 61 may provide functionality supporting the MAC and RLC layers, and the CU 62 may provide functionality supporting the PDCP, SDAP, and RRC layers.

[0373] <Radio Unit (RU)> FIG. 9 is a block diagram illustrating the main components of an exemplary RU 60, e.g., the RU portion of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a base station for Beyond 5G, or a 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 network 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 (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.

[0374] The communications 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 entities, such as the UE 3, other RUs 60, and the DU 61. The signaling may include, for example, appropriately formatted signaling messages relating to the radio connection and connectivity with the RU 60 (for a particular UE 3), in particular the MAC and RLC layers.

[0375] 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.

[0376] 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).

[0377] As described above, the RU 60 may be integrated / combined with the DU 61 as an integration / combination unit. Any function described for the RU 60 may be implemented in the integration / combination unit.

[0378] <Distributed Unit (DU)> FIG. 10 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, a base station for Beyond 5G, or a 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 the RU 60) via a network interface 612. A controller 613 controls the operation of the DU 61 in accordance with software stored in memory 614. For example, the software may be pre-installed in the memory 614 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6141 and a communications control module 6142 having at least a transceiver control module 61421. The communications control module 6142 (using its transceiver control module 61421) ) , DU 61 and other nodes or units, such as RU 60 and other nodes and units.

[0379] 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).

[0380] As mentioned above, the RU 60 may be integrated / combined with the DU 61 or the CU 62 as an integrated / combined unit. Any functionality described for the DU 61 may be implemented in one of the integrated / combined units.

[0381] <Centralized Unit (CU)> FIG. 11 is a block diagram illustrating the main components of an exemplary CU 62, e.g., the CU portion of a base station (eNB in ​​LTE, gNB in ​​5G, a base station for Beyond 5G, or a 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 the DU 61) via a network interface 622. A controller 623 controls the operation of the CU 62 in accordance with software stored in memory 624. For example, the software may be pre-installed in the memory 624 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6241 and a communications control module 6242 having at least a transceiver control module 62421. The communications control module 6242 (using its transceiver control module 62421) ) , CU 62 and other nodes or units, such as DU 61 and other nodes and units.

[0382] 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).

[0383] As described above, the CU 62 may be integrated / combined with the DU 61 as an integration / combination unit. Any functionality described for the CU 62 may be implemented in the integration / combination unit.

[0384] <amf> FIG. 12 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 in accordance with software stored in a memory 704. For example, the software may be pre-installed in the memory 704 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7041 and a communications control module 7042 having at least a transceiver control module 70421. The communications control module 7042 (using its transceiver control module 70421) ) , AMF 70, and UE 3 (e.g., via (R)AN node 5) and a core network node in UE 3's HPLMN (when UE 3 is roaming in). ) It is responsible for processing (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UE 3).

[0385] 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).

[0386] <upf> FIG. 13 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 in accordance with 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 communications control module 7242 having at least a transceiver control module 72421. The communications control module 7242 (using its transceiver control module 72421) ) , UPF 72, SMF 71, and core network nodes in the HPLMN of UE 3 when UE 3 is roaming in. ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. Such signaling may include, for example, appropriately formatted signaling messages (e.g., GPRS Tunneling Protocol (GTP) for the user plane) related to user data processing (for UE 3).

[0387] 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).

[0388] <pcf> FIG. 14 is a block diagram illustrating the main components of the PCF 73. As shown, the device includes a transceiver circuit 731 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 732. A controller 733 controls the operation of the PCF 73 in accordance with software stored in memory 734. For example, the software may be pre-installed in 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 communications control module 7342 having at least a transceiver control module 73421. The communications control module 7342 (using its transceiver control module 73421) ) , PCF 73, AMF 70, and core network nodes in the HPLMN of UE 3 when UE 3 is roaming in. ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UEs 3).

[0389] 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).

[0390] <ausf> FIG. 15 is a block diagram illustrating the major components of the AUSF 74. As shown, the device includes a transceiver circuit 741 operable to transmit signals to and receive signals from other nodes (including UDMs 75) via a network interface 742. A controller 743 controls the operation of the AUSF 74 in accordance with software stored in memory 744. For example, the software may be pre-installed in memory 744 and / or downloaded via a telecommunications network or from a removable data storage device (e.g., a removable memory device (RMD)). The software 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) ) , AUSF 74, AMF 70, and core network nodes in the HPLMN of UE 3 when UE 3 is roaming in. ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UEs 3).

[0391] The AUSF 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).

[0392] <udm> FIG. 16 is a block diagram illustrating the major 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 in accordance with software stored in memory 754. For example, the software may be pre-installed in memory 754 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7541 and a communications control module 7542 having at least a transceiver control module 75421. The communications control module 7542 (using its transceiver control module 75421) ) , UDM 75, AMF 70, and core network nodes in the VPLMN of UE 3 when UE 3 is roaming out. ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UEs 3).

[0393] 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).

[0394] <nwdaf> Figure 17 is a block diagram illustrating the major components of the NWDAF 76. As shown, the device includes a transceiver circuit 761 a transceiver circuit 761 is operable to transmit signals to and receive signals from other nodes (including the AMF 70, SMF 71, and NSACF 77) via the network interface 762. The controller 763 controls the operation of the NWDAF 76 in accordance with software stored in the memory 764. For example, the software may be pre-installed in the memory 764 and / or downloaded via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7641 and a communications control module 7642 having at least a transceiver control module 76421. The communications control module 7642 (using its transceiver control module 76421) ) , NWDAF 76, AMF 70, and (including core network nodes in the VPLMN of UE 3 when UE 3 is roaming out) ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UEs 3).

[0395] 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).

[0396] <nsacf> FIG. 18 is a block diagram illustrating the major 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) via a network interface 772. A controller 773 controls the operation of the NSACF 77 in accordance with software stored in 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 communications control module 7742 having at least a transceiver control module 77421. The communications control module 7742 (using its transceiver control module 77421) ) , NSACF 77, AMF 70, and core network nodes in the VPLMN of UE 3 when UE 3 is roaming out. ) It is responsible for handling (generating / sending / receiving) signaling to and from other nodes, such as other core network nodes. 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 UEs 3).

[0397] The NSACF 77 may support a Non-Public Network (NPN). The NPN may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The NSACF 7701 and NSACF 7702 may have the same components as the NSACF 77.

[0398] All or part of the exemplary aspects of the above disclosure may be described as follows, but are not limited to the following.

[0399] <4.2.11.2 Procedure for checking and updating the availability of the number of UEs per network slice> The procedure for checking and updating the availability of the number of UEs per network slice updates (i.e., increases or decreases) the number of UEs registered in the S-NSSAI that comply with NSAC. The AMF consists of information indicating which network slices comply with NSAC.

[0400]

[0401] Figure 4.2.11.2-1: Procedure for checking and updating the availability of the number of UEs per network slice (see Figure 19).

[0402] 1. If the AMF does not know which NSACF to communicate with, the AMF performs an NSACF discovery as described in clauses 6.3.22 and 5.2.7.3.2 of TS 23.501 [2]. If a 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 (i.e., the AMF requests the UE to deregister from the S-NSSAI), the AMF triggers the UE number availability check and update procedure per network slice to update the number of UEs registered in the network slice. Trigger events in the AMF also include a change in the authorized NSSAI in the case of inter-AMF mobility. The procedure is triggered in the following cases:

[0403] - during the UE registration procedure according to clause 4.2.2.2.2 (including registration type initial registration or mobility registration update for inter-AMF mobility in CM-CONNECTED or CM-IDLE state) --If EAC mode is active, before the registration approval in step 21, or --After the registration approval message if EAC mode is not active

[0404] - in a UE deregistration procedure according to clause 4.2.2.3, after the deregistration procedure is completed

[0405] - in a UE configuration update procedure (which may result from an NSSAA procedure or a change in the subscribed S-NSSAI) --If EAC mode is active and the update flag is increased, before the UE configuration update message, If EAC mode is active and the update flag is decreased, after a UE configuration update message, or --After a UE Configuration Update message if EAC mode is not active.

[0406] Note 1: Depending on the deployment, there may be different NSACFs for different S-NSSAIs according to NSAC, so during registration, the AMF triggers the availability check and update procedure of the number of UEs per network slice to multiple NSACFs.

[0407] 2. The AMF sends an Nnsacf_NSAC_NumOfUEsUpdate_Request message to the NSACF. The AMF includes in the message the UE ID, the access type, the S-NSSAI, the NF ID, and an update flag indicating whether the number of UEs registered in the S-NSSAI is increased if the UE achieves registration for the network slice according to NSAC, or whether the number of UEs registered in the S-NSSAI is decreased if the UE is deregistered from the S-NSSAI or fails to update the UE's registration for the S-NSSAI according to NSAC.

[0408] When performing an NSAC procedure for an S-NSSAI with the NSACF for the first time, the AMF includes a notification endpoint for EAC notifications to implicitly subscribe to EAC notifications for the S-NSSAI from the NSACF.

[0409] 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.

[0410] If the update flag parameter from the AMF indicates an increase, the following applies:

[0411] 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 the current number of UEs will not be increased. The NSACF shall create a new entry associated with this new update and maintain the old entry associated with the previous update. Multiple entries for the same UE ID in the NSACF are distinguished based on the NF ID of the NF sending the update request. When the NSACF receives a request with an update flag indicating a decrease, it removes the entry associated with the NF ID.

[0412] Note 2: Use cases with more than one entry in the NSACF for the same UE may occur (a) during inter-AMF mobility when a new AMF requests an update from the NSACF before the old AMF sends a request to deregister the UE, or (b) during PDN connection establishment in the EPC when multiple SMFs+PGW-Cs (i.e., those used for different PDN connections associated with the same S-NSSAI) send update requests for the maximum number of UEs to the NSACF.

[0413] 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 as a new entry associated with this new update, 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.

[0414] 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 multiple entries associated with the UE ID, the NSACF removes the entry associated with the NF ID, but the UE ID is maintained in the list of UEs registered in the S-NSSAI.

[0415] The NSACF takes into account the access type to increase and decrease the number of UEs per network slice, as described in clause 5.15.11.1 of TS23.501 [2].

[0416] The NSACF stores the notification endpoint for the EAC notification associated with the S-NSSAI when it is received from the AMF. The NSACF may use this AMF notification endpoint to update the EAC mode as described in clause 4.2.11.3.

[0417] NOTE 3: This allows the NSACF to maintain up-to-date information about the AMFs it serves to the S-NSSAI.

[0418] If the AMF includes a usage control parameter and a usage control timer value that are set to on for one or more network slices for the UE, the NSACF starts the usage control timer for the network slice for the UE using the timer value provided by the AMF. Alternatively, the usage control timer value may be a configured value in the NSACF. The usage control timer for a specific network slice for the UE stops when a PDU session is established by the UE in the network slice and resumes as soon as the PDU session is released.

[0419] 4. The NSACF returns an Nnsacf_NSAC_NumOfUEsUpdate_Response, and the NSACF includes in the Nnsacf_NSAC_NumOfUEsUpdate_Response an S-NSSAI that has already reached the maximum number of UEs per network slice, along with a result parameter indicating that the maximum number of UEs registered in the network slice has been reached.

[0420] When the usage control timer for a network slice expires for a UE, for example, if the network slice has not been used by the UE for the duration of the usage control timer, the NSACF deregisters the UE from the network slice, i.e., the NSACF decrements the UE count for the network slice and removes the UE identity from the list of UEs registered in the network slice. The NSACF then returns an Nnsacf_NSAC_DeregistrationNotification message to the AMF, and the NSACF includes the UE identity, the network slice identity, and a reject cause set to "usage control timer expired" in the Nnsacf_NSAC_DeregistrationNotification message.

[0421] In the UE registration procedure, if only some of the S-NSSAIs have reached the maximum number of UEs per S-NSSAI, the AMF sends a registration accept message to the UE, in which the AMF includes the rejected S-NSSAIs for which the NSACF indicates that the maximum number of UEs per network slice has been reached in a rejected NSSAI list, and for each rejected S-NSSAI, the AMF includes a rejection cause set to "the maximum number of UEs per network slice has been reached" and optionally a back-off timer.

[0422] 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 comply with 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 parameter, 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.

[0423] NOTE 4: If a use case requires the UE to always remain reachable for 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. This ensures that the UE can access the service even if the maximum number of UEs per network slice has been reached.

[0424] <4.2.11.4 Procedure for checking and updating the availability of the number of PDU sessions per network slice> The PDU session number availability check and update procedure per network slice updates (i.e., increases or decreases) the number of PDU sessions established in the S-NSSAI that complies with the NSAC. The SMF is configured with information indicating which network slices comply with the NSAC.

[0425] Note 1: The EAC mode is not applicable to the procedure for checking and updating the availability of the number of PDU sessions per network slice.

[0426] Figure 4.2.11.4-1: Procedure for checking and updating the availability of the number of PDU sessions per network slice (see Figure 20).

[0427] 1. If the SMF does not know which NSACF to contact, it performs an NSACF discovery as described in clauses 6.3.22 and 5.2.7.3.2 of TS 23.501 [2]. The SMF anchoring the PDU session triggers the PDU session number availability check and update procedure for the network slices subject to NSAC at the beginning of the PDU session establishment procedure (clause 4.3.2.2.1 and 4.3.2.2.2) for only new PDU sessions to be established, as the last step of the successful PDU session release procedure (clause 4.3.4.2 and 4.3.4.3).

[0428] NOTE 2: For handover purposes, the SMF handling the PDU session associated with the UE request type "existing PDU session" does not interact with the NSACF.

[0429] 2. The SMF anchoring the PDU session sends an Nnsacf_NSAC_NumOfPDUsUpdate_Request message to the NSACF. The SMF includes in the message the UE-ID, the PDU session ID, the S-NSSAI for which the number of PDU sessions per network slice needs to be updated, the access type, and an update flag indicating that the number of PDUs established in the S-NSSAI is increased if the procedure is triggered at the beginning of a PDU session establishment procedure, or that the number of PDU sessions in the S-NSSAI is decreased if the procedure is triggered at the end of a PDU session release procedure.

[0430] NOTE 3: For SSC mode 3 PDU sessions, the SMF of the new PDU session calls the NSACF to increase the number of PDU sessions and adds a new PDU session ID in the NSACF. When the old PDU session is released, the SMF of the old PDU session calls the NSACF to decrease the number of PDU sessions and removes the old PDU session ID in the NSACF.

[0431] NOTE 4: An SMF that is the anchor for an IPv6 multihomed PDU session shall not invoke the NSACF for an S-NSSAI following NSAC if the PDU session replaces an existing anchor according to clause 4.3.5.3.

[0432] 3. The NSACF updates the current number of PDU sessions established in the S-NSSAI based on the information provided by the anchor SMF in the update flag parameter, i.e., increases or decreases the number of PDU sessions per network slice.

[0433] If the update flag parameter from the SMF anchoring the PDU session indicates an increase and the maximum number of PDU sessions established in the S-NSSAI has already been reached, the NSACF returns a result parameter indicating that the maximum number of PDU sessions per network slice has been reached. If the maximum number of PDU sessions established in the S-NSSAI has not been reached, the NSACF checks the UE ID. If the UE ID is defined, the NSACF stores the PDU session ID and increases the number of PDU sessions for the S-NSSAI. If the UE ID is not defined, the NSACF creates an entry for the UE ID, stores the PDU session ID, and increases the number of PDU sessions for the S-NSSAI.

[0434] If the update flag parameter from the SMF anchoring the PDU session indicates a decrease in the current number of PDU sessions per S-NSSAI, the NSACF determines the UE ID and decreases the number of PDU sessions for that S-NSSAI and its associated PDU session ID. If the UE ID no longer has any PDU sessions after the decrease, the NSACF removes the UE ID entry.

[0435] The NSACF takes into account the access type to increase and decrease the number of PDU sessions per S-NSSAI as described in clause 5.15.11.2 of TS 23.501 [2].

[0436] If the NSACF has an active usage control timer running for the network slice for the UE, the NSACF stops the usage control timer when the update flag for the network slice is set to increase, i.e., when a new PDU session is established by the UE in the network slice. The NSACF restarts the usage control timer for the network slice when the update flag for the network slice is set to decrease, i.e., when an active PDU session in the network slice is released by the UE.

[0437] 4. The NSACF informs the anchor SMF of the update using the Nnsacf_NSAC_NumOfPDUsUpdate_Response message. If the NSACF returns a result of the maximum number of PDU sessions per S-NSSAI being reached, the SMF rejects the PDU session establishment request with the reject cause set to "Maximum number of PDU sessions per S-NSSAI being reached" and optionally a back-off timer.

[0438] In case of a PDU session establishment failure, the anchor SMF triggers another request to the NSACF with an update flag parameter equal to decrement to readjust the PDU session counters back at the NSACF.

[0439] <5.2.21.2.2 Nnsacf_NSAC_NumOfUEsUpdate service operation> Service action name: Nnsacf_NSAC_NumOfUEsUpdate

[0440] Description: When the UE registration status for a network slice according to NSAC is changed, the number of UEs registered in the network slice is updated (e.g., increased or decreased). Also, when the number of UEs registered in the network slice is increased and the Early Availability Check (EAC) mode in the NSACF is activated for the network slice (see Nnsacf_NSAC_EACNotify service operation), the NSACF first checks whether the number of UEs registered in the network slice has reached the maximum number of UEs per network slice threshold. If the maximum number of UEs registered in the network slice has already been reached, UE registration for the network slice is rejected. If EAC is not activated, the NSACF increases or decreases the number of UEs per network slice according to the following input parameters:

[0441] Input required: S-NSSAI, UE ID (SUPI), NF ID, access type, update flag.

[0442] Input, conditional: Notification endpoint for EAC Notification for the S-NSSAI.

[0443] The S-NSSAI parameter is a list of one or more network slices in which the number of UEs registered in the network slice is updated and confirmed if the maximum number of UEs per network slice threshold has already been reached.

[0444] The UE ID is used by the NSACF to maintain a list of UE IDs registered in the network slice. The NSACF also takes into account the access type to increase and decrease the number of UEs per network slice, as described in clause 5.15.11.1 of TS 23.501 [2].

[0445] The NF ID parameter is the NF instance ID of the NF (e.g., AMF or SMF+PGW-C) sending the request to the NSACF.

[0446] The update flag input parameter indicates whether the number of UEs registered in the network slice is as follows:

[0447] -When a UE registers to a new network slice according to NSAC, the number of UEs registered in the network slice is increased. 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 the number of UEs registered in the network slice is not increased. -If the UE ID is not in the list of UE IDs registered in the network slice and the maximum number of UEs registered in the network slice has not yet been reached, the NSACF adds the UE ID to the list of UEs registered in the network slice and increases the number of UEs registered in the network slice. If the UE_ID is not in the list of UEs registered in the S-NSSAI and the maximum number of UEs per network slice for the S-NSSAI has already been reached, the NSACF returns the result of reaching the maximum number of UEs per network slice.

[0448] When a UE is deregistered for a network slice according to NSAC, the number of UEs registered in the network slice is reduced. The NSACF reduces the number of UEs registered in the network slice and removes the UE ID from the list of UEs registered in the network slice.

[0449] When performing an NSAC procedure for an S-NSSAI with the NSACF for the first time, the AMF includes a notification endpoint for EAC notifications to implicitly subscribe to EAC notifications for the S-NSSAI from the NSACF.

[0450] Input, options: usage control, usage control timer

[0451] The usage control timer per network slice for the UE is included when the network slice is subject to usage control, i.e., when the UE is deregistered from the network slice by the NSACF if the network slice is not used by the UE for a specific duration.

[0452] A usage control timer may be included if the network slice is subject to usage control.

[0453] The NSACF may optionally return the current state of network slice availability (e.g., percentage of the maximum number of UEs registered in the network slice) in the availability status parameter. This information may be used for NSACF signaling and load balancing when multiple NSACFs are serving the same network slice.

[0454] Editor's note: If multiple NSACFs are supported, e.g., if they find the same NSACF, how to support local maximum number adjustments between NSACFs is FFS (requires further study).

[0455] Output, required: maximum number of UEs per network slice reached, availability status.

[0456] <5.2.21.xx Nnsacf_NSAC_DeregistrationNotification service operation> Service action name: Nnsacf_NSAC_DeregistrationNotification

[0457] Description: For a network slice, the UE is notified by the NSACF that the UE has been deregistered due to expiration of the usage control timer for that network slice for the UE.

[0458] Input required: UE_ID, S-NSSAI, reject cause.

[0459] The UE_ID parameter is the identification information of the UE that will be deregistered from the network slice due to the expiration of the usage control timer.

[0460] The S-NSSAI parameter is the duration of the usage control timer and the network slice identity information that the UE is not using.

[0461] The rejection cause parameter is set to the duration of the usage control timer, or "usage control timer expired" if the UE is not using the S-NSSAI.

[0462] <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. By way of example only, many such alternatives and modifications are now described.

[0463] 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 be provided in this manner for particular applications, for example, where an existing system is modified to implement the present disclosure; in other applications, for example, in a system designed with inventive features in mind from the beginning; however, these modules may not be recognizable as separate entities because 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.

[0464] Each controller may comprise 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, communication buses (e.g., control buses, data buses, and / or address buses), direct memory access (DMA) functions, hardware or software-implemented counters, pointers, and / or timers, and / or the like.

[0465] In the above embodiments, a number of software modules have been described. Those skilled in the art will understand that the software modules may be provided in compiled or uncompiled form, and may be provided to the UE 3 and network devices as signals over 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 is preferred for updating the functions of the UE 3 and network devices, as they facilitate updating the UE 3 and network devices.

[0466] In the above embodiment, 3GPP wireless communication (radio access) technology is used, but 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 in accordance with the above embodiment.

[0467] Items of user equipment may include, for example, communication devices such as mobile phones, smartphones, user devices, 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, this application will refer to mobile devices (or UEs) in the description, but it will be understood that the described techniques may be implemented on any (mobile and / or generally fixed) 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 by software instructions stored in memory.

[0468] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0469] As will be appreciated by those skilled in the art, the present disclosure may be embodied as a method and a system, and thus may take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0470] It will be understood that each block of the block diagrams can be implemented by computer program instructions. The computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to create a machine, such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for implementing the function / acts specified in the block or blocks of the flowcharts and / or block diagrams. A general-purpose processor can be a microprocessor, but alternatively, the processor can be any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., multiple microprocessors, one or more microprocessors, or any other such configuration.

[0471] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC.

[0472] The previous description of examples of the present disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the examples will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples set forth herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0473] 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 herein. For example, the above embodiments are not limited to 5GS, and the embodiments may also be applied to communication systems other than 5GS (e.g., 6G systems, Beyond 5G systems).

[0474] All or part of the embodiments disclosed above may be described as, but not limited to, the following supplementary notes.

[0475] Appendix 1. A method for a communication device, the method comprising: sending a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a second message if the S-NSSAI has not been used for a period of time; the second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used in the period; the time period is associated with the S-NSSAI; and transmitting a third message to remove the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI); the third message includes the S-NSSAI and the rejection cause; A method comprising:

[0476] Supplementary Note 2. The first message is sent for Network Slice Admission Control (NSAC); 2. The method of claim 1, wherein the NSAC is administered when the period of time has elapsed.

[0477] Clause 3. The method of clause 2, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0478] Supplementary Note 4. The period is configured by the communication device; 4. The method of any one of claims 1 to 3, wherein the period is included in the first message.

[0479] Appendix 5. A method for a communication device, the method comprising: receiving a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and starting a timer for the S-NSSAI after receiving the first message; the timer is set to a value associated with the S-NSSAI; and performing Network Slice Admission Control (NSAC) when the timer expires; transmitting a second message after performing the NSAC; the second message includes the S-NSSAI and a reject cause indicating expiration of the timer; A method comprising:

[0480] Clause 6. The method of clause 5, wherein the first message is for the NSAC.

[0481] Appendix 7. The method of any one of Appendixes 5 to 6, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0482] Clause 8. The method of any one of clauses 5 to 7, wherein the value is configured by the communications device.

[0483] Supplementary Note 9. After starting the timer, receiving a third message associated with a Protocol Data Unit (PDU) session for the S-NSSAI; stopping the timer after receiving the third message; 9. The method of any one of claims 5 to 8, further comprising:

[0484] Supplementary Note 10. A method for a User Equipment (UE), the method comprising: Performing a registration for Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a message, the message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time; the time period is associated with the S-NSSAI; and After receiving the message, removing the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI); and A method comprising:

[0485] Appendix 11. A method for a communication device, the method comprising: receiving a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and starting a timer for the S-NSSAI after receiving the first message; the timer is set to a value associated with the S-NSSAI; and transmitting a second message and a third message for Network Slice Admission Control (NSAC) when the timer expires; the second message includes the S-NSSAI; the third message includes the S-NSSAI and a reject cause indicating expiration of the timer; A method comprising:

[0486] Clause 12. The method of clause 11, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0487] Clause 13. The method of clause 11 or 12, wherein the value is configured by the communications device.

[0488] Supplementary Note 14. After starting the timer, receiving a fourth message related to a Protocol Data Unit (PDU) session for the S-NSSAI; stopping the timer after receiving the fourth message; 14. The method of any one of claims 11 to 13, further comprising:

[0489] Appendix 15. A method for a communication device, the method comprising: receiving a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and starting a timer for the S-NSSAI after receiving the first message; the timer is set to a value associated with the S-NSSAI; and receiving a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI after starting the timer; stopping the timer after receiving the second message; receiving a third message related to the release of the PDU session after stopping the timer; starting the timer after receiving the third message; sending a fourth message when the timer expires; The fourth message is for removing the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI; and A method comprising:

[0490] Appendix 16. A method for a communication device, the method comprising: sending a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and receiving a second message, the second message includes a Protocol Data Unit (PDU) session identification; and starting a timer after receiving the second message; transmitting a third message if there is no user plane activity for the PDU session until the timer expires; the third message indicates no user plane operation for the PDU session; and receiving a fourth message after sending the third message; performing a procedure for releasing the PDU session after receiving the fourth message; A method comprising:

[0491] Appendix 17. A method for a communication device, the method comprising: receiving a first message, the first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and sending a second message, the second message includes a Protocol Data Unit (PDU) session identification; and receiving a third message after sending the second message; the third message indicates no user plane operation for the PDU session; and sending a fourth message after receiving the third message; The fourth message is for performing a procedure for releasing the PDU session; and A method comprising:

[0492] Appendix 18. A communication device, the communication device comprising: a means for transmitting a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and means for receiving a second message if the S-NSSAI has not been used for a period of time, the second message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used in the period; The time period is associated with the S-NSSAI; means for transmitting a third message to remove the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI), the third message includes the S-NSSAI and the rejection cause; A communication device comprising:

[0493] Addendum 19. The first message is sent for Network Slice Admission Control (NSAC); 19. The communication device of claim 18, wherein the NSAC is performed when the period elapses.

[0494] Appendix 20. The communications device of Appendix 19, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0495] Addendum 21. The period is configured by the communication device; 21. The communication device of claim 18, wherein the period is included in the first message.

[0496] Appendix 22. A communication device, the communication device comprising: a means for receiving a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and means for starting a timer for the S-NSSAI after receiving the first message, The timer is set to a value associated with the S-NSSAI; means for performing Network Slice Admission Control (NSAC) when the timer expires; a means for transmitting a second message after performing the NSAC, the second message includes the S-NSSAI and a reject cause indicating expiration of the timer; A communication device comprising:

[0497] Appendix 23. The communications device of Appendix 22, wherein the first message is for the NSAC.

[0498] Appendix 24. The communications device of Appendix 22 or 23, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0499] Addendum 25. The communications device of any one of Addendums 22 to 24, wherein the value is configured by the communications device.

[0500] Supplementary Note 26. Means for receiving a third message associated with a Protocol Data Unit (PDU) session for said S-NSSAI after starting said timer; means for stopping the timer after receiving the third message; 26. The communication device of any one of appendices 22 to 25, further comprising:

[0501] Supplementary Note 27. A User Equipment (UE), comprising: a means for registering for Single Network Slice Selection Assistance Information (S-NSSAI); A means for receiving a message, the message includes the S-NSSAI and a rejection cause indicating that the S-NSSAI has not been used for a period of time; The time period is associated with the S-NSSAI; means for removing the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI) after receiving the message; UE equipped with.

[0502] Addendum 28. A communication device, the communication device comprising: a means for receiving a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and means for starting a timer for the S-NSSAI after receiving the first message, The timer is set to a value associated with the S-NSSAI; means for transmitting a second message and a third message for Network Slice Admission Control (NSAC) when the timer expires, the second message includes the S-NSSAI; the third message includes the S-NSSAI and a reject cause indicating expiration of the timer; A communication device comprising:

[0503] Appendix 29. The communications device of Appendix 28, wherein the NSAC includes a reduction in the number of User Equipment (UE).

[0504] Appendix 30. The communications device of any one of Appendixes 28 and 29, wherein the value is configured by the communications device.

[0505] Supplementary Note 31. Means for receiving a fourth message associated with a Protocol Data Unit (PDU) session for said S-NSSAI after starting said timer; means for stopping the timer after receiving the fourth message; 31. The communication device of any one of appendices 28 to 30, further comprising:

[0506] Addendum 32. A communication device, the communication device comprising: a means for receiving a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and means for starting a timer for the S-NSSAI after receiving the first message, The timer is set to a value associated with the S-NSSAI; means for receiving a second message related to establishment of a Protocol Data Unit (PDU) session for the S-NSSAI after starting the timer; means for stopping the timer after receiving the second message; means for receiving a third message related to the release of the PDU session after stopping the timer; means for starting the timer after receiving the third message; means for transmitting a fourth message when the timer expires, The fourth message is for removing the S-NSSAI from an authorized Network Slice Selection Assistance Information (NSSAI) or for deregistering the S-NSSAI; and A communication device comprising:

[0507] Addendum 33. A communication device, the communication device comprising: a means for transmitting a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and means for receiving a second message, the second message includes a Protocol Data Unit (PDU) session identification; means for starting a timer after receiving the second message; means for transmitting a third message if there is no user plane activity for the PDU session until the timer expires, the third message indicates no user plane operation for the PDU session; means for receiving a fourth message after transmitting the third message; means for performing a procedure for releasing the PDU session after receiving the fourth message; A communication device comprising:

[0508] Addendum 34. A communication device, the communication device comprising: a means for receiving a first message, The first message includes Single Network Slice Selection Assistance Information (S-NSSAI); and a means for transmitting a second message, the means comprising: the second message includes a Protocol Data Unit (PDU) session identification; means for receiving a third message after sending the second message, the third message indicates no user plane operation for the PDU session; means for transmitting a fourth message after receiving the third message, The fourth message is for performing a procedure for releasing the PDU session; and A communication device comprising:

[0509] Addendum 35. A method of a first core network device, comprising: receiving a fourth message related to management of the network slice from a second core network device; starting a timer for the network slice after receiving the fourth message; detecting that the timer has expired; After detecting that the timer has expired, sending a fifth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use; and A method comprising:

[0510] Addendum 36. A method of a first core network device, comprising: receiving a fourth message related to management of the network slice from a second core network device; starting a timer for the network slice after receiving the fourth message; Detecting an operation related to the network slice; and stopping the timer after said detection of said motion; A method comprising:

[0511] Addendum 37. A method of a third core network device, comprising: analyzing data related to a network to which the third core network device belongs; receiving a sixth message related to management of the network slice from the first core network device; starting a timer for the network slice after receiving the sixth message; detecting that the timer has expired; After the detection that the timer has expired, sending a seventh message to the first core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use, wherein the first core network device manages network slice admission control; and A method comprising:

[0512] Addendum 38. A method of a third core network device, comprising: analyzing data related to a network to which the third core network device belongs; receiving a sixth message related to management of the network slice from the first core network device; starting a timer for the network slice after the reception of the sixth message; Detecting an operation related to the network slice; and After the detection of the operation, stopping the timer, wherein the first core network device manages network slice admission control; and A method comprising:

[0513] Addendum 39. A method of a first network slice control function node, comprising: receiving an eighth message related to management of the network slice from the second core network device; starting a timer for the network slice after receiving the eighth message; detecting that the timer has expired; After detecting that the timer has expired, sending a ninth message to the second core network device indicating at least one of that the timer has expired or that the network slice associated with the timer is not in use; and A method comprising:

[0514] Addendum 40. A method of a first network slice control function node, comprising: receiving a tenth message related to management of the network slice from the second core network device; starting a timer for the network slice after receiving the tenth message; receiving an eleventh message from a second network slice control function node detecting an operation related to the network slice; stopping the timer after receiving the eleventh message; A method comprising:

[0515] Addendum 41. A method of a third core network device, comprising: Sending first information related to management of the network slice to a first core network device to start controlling the number of sessions based on a timer; receiving second information from the first core network device indicating that the control is to be initiated; monitoring user plane operations associated with the session after receiving the second information; sending third information to the first core network device, indicating that the user plane operation is not detected based on the monitoring; and receiving fourth information from the first core network device indicating at least one of the timer expiring or the session not being active within a period specified by the timer; A method comprising:

[0516] Addendum 42. A method of a first core network device, comprising: receiving fifth information related to management of the network slice from a third core network device; After receiving the fifth information, starting a timer for the network slice; Sending sixth information to the third core network device indicating that the management is initiated to start monitoring user plane operations related to the network slice; receiving seventh information from the third core network device indicating that the user plane operation is not detected based on the monitoring; and sending eighth information to the third core network device indicating at least one of the expiration of the timer or the inactivity of the session within a period of time specified by the timer; A method comprising:

[0517] Although the present invention has been described above with reference to the embodiments (and examples), the present invention is not limited to the above-described 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.

[0518] This application claims priority to Indian Provisional Patent Application No. 202111060026, filed on December 22, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0519] 1. Telecommunications Systems 3UE 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 61 DU 62 CU 70 AMF 71 SMF 72 UPF 73 PCF 74 AUSF 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 721 Transceiver Circuit 722 network interface 723 Controller 724 memory 731 Transceiver Circuit 732 network interface 733 Controller 734 memory 741 Transceiver Circuit 742 network interfaces 743 Controller 744 memory 751 Transceiver Circuit 752 network interfaces 753 Controller 754 memory 761 Transceiver Circuit 762 network interfaces 763 Controller 764 memory 771 Transceiver Circuit 772 network interfaces 773 Controller 774 memory 3621 Transceiver Control Module 5521 Transceiver Control Module 6051 Operating System 6052 Communication Control Module 6141 Operating System 6142 Communication Control Module 6241 Operating System 6242 Communication Control Module 7041 Operating System 7042 Communication Control Module 7241 Operating System 7242 Communication Control Module 7341 Operating System 7342 Communication Control Module 7441 Operating System 7442 Communication Control Module 7541 Operating Systems 7542 Communication Control Module 7641 Operating System 7642 Communication Control Module 7701 NSACF 7702 NSACF 7741 Operating System 7742 Communication Control Module 60521 Transceiver Control Module 61421 Transceiver Control Module 62421 Transceiver Control Module 70421 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> < / nwdaf> < / udm> < / ausf> < / pcf> < / upf> < / amf>

Claims

1. A first network function that controls a PDU (Protocol Data Unit) session of a network slice is provided with a session timer associated with an S-NSSAI (Single-Network Slice Selection Assistance Information) that is an identifier of the network slice; receiving a notification from the first network function regarding the release of the PDU session when the session timer expires; The process for releasing the network slice is initiated based on the release cause of the release of the PDU session. SMF (Session Management Function) method.

2. The release cause is related to slice inactivity.

10. The SMF method of claim 1.

3. Set the session timer value, 10. The SMF method of claim 1.

4. the session timer is a session inactivity timer; 10. The SMF method of claim 1.

5. The session timer is associated with a PDU session.

5. The SMF method of claim 4.

6. A means for providing a session timer associated with S-NSSAI (Single-Network Slice Selection Assistance Information), which is an identifier of a network slice, to a first network function that controls a PDU (Protocol Data Unit) session of the network slice; means for receiving a notification regarding the release of the PDU session from the first network function when the session timer expires; The process for releasing the network slice is initiated based on the release cause of the release of the PDU session. SMF (Session Management Function).

7. The release cause is related to slice inactivity. The SMF of claim 6.

8. A means of setting the session timer value The SMF of claim 6 comprising:

9. the session timer is a session inactivity timer; The SMF of claim 6.

10. The session timer is associated with a PDU session. The SMF of claim 9.

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