Apparatus and method for configuring slice deregistration inactivity timer in wireless communication system

Abstract

The present disclosure relates to an apparatus and a method for configuring a slice deregistration inactivity timer in a wireless communication system. This method performed by a network node comprises the steps of: receiving, from a terminal, a first message for requesting registration; transmitting, to the terminal, a second message for accepting the registration; configuring a protocol data unit (PDU) session for the terminal; transmitting a third message indicating release of the PDU session; and starting a slice deregistration inactivity timer related to a slice for the terminal, wherein the value of the slice deregistration inactivity timer can be determined on the basis of information obtained using a network data analytics function (NWDAF) node.

Description

Device and method for setting a slice deregistration inactivity timer in a wireless communication system

[0001] The following description relates to a wireless communication system, and more particularly, to a device and method for setting a slice deregistration inactivity timer in a wireless communication system.

[0002] Wireless access systems are widely deployed to provide various types of communication services, such as voice and data. Typically, wireless access systems are multiple access systems that support communications with multiple users by sharing available system resources (e.g., bandwidth, transmission power). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA).

[0003] In particular, as numerous communication devices demand greater communication capacity, enhanced mobile broadband (eMBB) communication technologies are being proposed, improving upon existing radio access technology (RAT). Furthermore, massive machine type communications (mMTC), which connects multiple devices and objects to provide diverse services anytime and anywhere, as well as communication systems that consider reliability and latency-sensitive services / user equipment (UE), are being proposed. Various technological configurations are being proposed for these solutions.

[0004] The present disclosure relates to a device and method for setting a slice deregistration inactivity timer in a wireless communication system.

[0005] The present disclosure relates to a device and method for setting a slice deregistration inactivity timer value using a network data analytics function (NWDAF) in a wireless communication system.

[0006] The present disclosure relates to a device and method for adjusting a slice deregistration inactivity timer value based on information periodically exchanged between an access and mobility management function (AMF) and an NWDAF in a wireless communication system.

[0007] The present disclosure relates to a device and method for adjusting a slice deregistration inactivity timer value based on at least one of network load information, AMF load information, and the number of usage failure reports in a wireless communication system.

[0008] The present disclosure relates to a device and method for transmitting an adjusted slice deregistration inactivity timer value to a user equipment (UE) using a registration accept message or a UE configuration update command message in a wireless communication system.

[0009] The present disclosure relates to a device and method for periodically exchanging network data analysis information related to on-demand S-NSSAI (single network slice selection assistance information) between AMF and NWDAF in a wireless communication system.

[0010] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other technical tasks not mentioned can be considered by a person having ordinary skill in the technical field to which the technical configuration of the present disclosure is applied from the embodiments of the present disclosure described below.

[0011] As an example of the present disclosure, a method performed by a network node in a wireless communication system includes the steps of receiving a first message requesting registration from a terminal, transmitting a second message accepting registration to the terminal, establishing a protocol data unit (PDU) session for the terminal, transmitting a third message indicating release of the PDU session, and starting a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained using a network data analytics function (NWDAF) node.

[0012] As an example of the present disclosure, a method performed by a terminal in a wireless communication system includes the steps of transmitting a first message requesting registration to a network node, receiving a second message accepting registration from the network node, establishing a PDU session for the terminal and a network, receiving a third message from the network node indicating release of the PDU session, and starting a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained from a network data analytics function (NWDAF) node at an access and mobility management function (AMF) node.

[0013] As an example of the present disclosure, in a wireless communication system, a network node includes a transceiver and a processor connected to the transceiver, wherein the processor receives a first message requesting registration from a terminal, transmits a second message accepting registration to the terminal, establishes a PDU session for the terminal, transmits a third message instructing release of the PDU session, and starts a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained using a network data analytics function (NWDAF) node.

[0014] As an example of the present disclosure, in a wireless communication system, a terminal includes a transceiver and a processor connected to the transceiver, wherein the processor transmits a first message requesting registration to a network node, receives a second message accepting registration from the network node, establishes a PDU session for the terminal and a network, receives a third message instructing release of the PDU session from the network node, and starts a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained from a network data analytics function (NWDAF) node at an access and mobility management function (AMF) node.

[0015] As an example of the present disclosure, a communication device includes at least one processor, and at least one computer memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, direct operations, the operations including: transmitting a first message requesting registration to a network node, receiving a second message accepting registration from the network node, establishing a PDU session with the terminal and a network, receiving a third message from the network node indicating release of the PDU session, and starting a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained from a network data analytics function (NWDAF) node at an access and mobility management function (AMF) node.

[0016] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction includes at least one instruction executable by a processor, the at least one instruction causing a device to receive a first message requesting registration from a terminal, transmit a second message accepting registration to the terminal, establish a PDU session for the terminal, transmit a third message indicating release of the PDU session, and start a slice deregistration inactivity timer associated with a slice for the terminal, wherein a value of the slice deregistration inactivity timer can be determined based on information obtained using a network data analytics function (NWDAF) node.

[0017] The above-described aspects of the present disclosure are only some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the present disclosure can be derived and understood by a person having ordinary skill in the art based on the detailed description of the present disclosure to be described below.

[0018] The following effects may be achieved by embodiments based on the present disclosure.

[0019] The present disclosure can prevent unnecessary signaling from occurring due to a difference between the expiration time of a terminal's slice deregistration inactivity timer and the expiration time of a network's slice deregistration inactivity timer.

[0020] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure is applied, from the description of the embodiments of the present disclosure below. In other words, unintended effects that result from implementing the configuration described in the present disclosure can also be derived by those skilled in the art from the embodiments of the present disclosure.

[0021] The accompanying drawings are intended to aid understanding of the present disclosure and may provide embodiments of the present disclosure along with detailed descriptions. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0022] Figure 1 illustrates an example of a communication system applicable to the present disclosure.

[0023] FIG. 2 illustrates an example of a user equipment (UE) applicable to the present disclosure.

[0024] FIG. 3 illustrates an example of functional separation of a next generation radio access network (NG-RAN) and a 5th generation core (5GC) applicable to the present disclosure.

[0025] FIG. 4 illustrates an example of a general architecture of a 5G (5th generation) system applicable to the present disclosure.

[0026] FIG. 5 illustrates an example of a network data analysis subscription / unsubscription procedure applicable to the present disclosure.

[0027] Figure 6 illustrates an example of a slice deregistration inactivity timer execution procedure.

[0028] FIG. 7 illustrates an example of a procedure for executing a slice deregistration inactivity timer of an AMF according to one embodiment of the present disclosure.

[0029] FIG. 8 illustrates an example of a terminal slice deregistration inactivity timer execution procedure according to one embodiment of the present disclosure.

[0030] FIG. 9 illustrates an example of a slice deregistration inactivity timer setting procedure according to one embodiment of the present disclosure.

[0031] FIG. 10 illustrates a signaling example for setting a slice deregistration inactivity timer according to one embodiment of the present disclosure.

[0032] FIG. 11 illustrates an example of a slice deregistration inactivity timer adjustment procedure according to one embodiment of the present disclosure.

[0033] The following embodiments combine components and features of the present disclosure in a predetermined form. Each component or feature may be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, some components and / or features may be combined to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

[0034] In the description of the drawings, procedures or steps that may obscure the gist of the present disclosure are not described, and procedures or steps that can be understood by a person skilled in the art are also not described.

[0035] Throughout the specification, when a part is said to "comprising" or "including" a component, this does not mean that other components may be included, but rather that other components may be excluded, unless otherwise specifically stated. In addition, terms such as "...part," "...unit," and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. In addition, the words "a" or "an," "one," "the," and similar related words may be used in the context of describing the present disclosure (especially in the context of the claims below) to include both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0036] Embodiments of the present disclosure described herein focus on the data transmission and reception relationship between a base station and a mobile station. Here, the base station is understood as a terminal node of a network that directly communicates with the mobile station. Certain operations described herein as being performed by the base station may, in some cases, be performed by an upper node of the base station.

[0037] That is, in a network consisting of multiple network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this case, the term 'base station' may be replaced by terms such as fixed station, Node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.

[0038] Additionally, in embodiments of the present disclosure, the term terminal may be replaced with terms such as user equipment (UE), mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, or advanced mobile station (AMS).

[0039] Additionally, a transmitter refers to a fixed and / or mobile node that provides data or voice services, and a receiver refers to a fixed and / or mobile node that receives data or voice services. Therefore, for uplink, a mobile station can be the transmitter, and a base station can be the receiver. Similarly, for downlink, a mobile station can be the receiver, and a base station can be the transmitter.

[0040] Embodiments of the present disclosure are wireless access systems such as IEEE 802.xx system, 3rd Generation Partnership Project (3GPP) system, 3GPP Long Term Evolution (LTE) system, 3GPP 5G (5 th generation) NR (New Radio) system and 3GPP2 system, and in particular, embodiments of the present disclosure may be supported by 3GPP TS (technical specification) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPP TS 38.331 documents.

[0041] Furthermore, the embodiments of the present disclosure can be applied to other wireless access systems and are not limited to the aforementioned systems. For example, they can also be applied to systems implemented after the 3GPP 5G NR system, and are not limited to a specific system.

[0042] That is, obvious steps or parts not described in the embodiments of the present disclosure can be explained by referring to the above documents. In addition, all terms disclosed in this document can be explained by the above standard documents.

[0043] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the technical configurations of the present disclosure may be implemented.

[0044] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding the present disclosure, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present disclosure.

[0045] The following technology can be applied to various wireless access systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access).

[0046] For clarity, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical spirit of the present invention is not limited thereto. LTE may refer to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 may be referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 may be referred to as LTE-A pro. 3GPP NR may refer to technology after TS 38.xxx Release 15. 3GPP 6G may refer to technology after TS Release 17 and / or Release 18. "xxx" refers to a standard document detail number. LTE / NR / 6G may be collectively referred to as a 3GPP system.

[0047] For background information, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to the present invention. For example, reference may be made to the 36.xxx and 38.xxx standard documents.

[0048] For terms, abbreviations, and other background technology that may be used in this document, please refer to the following standards documents published prior to this document. In particular, terms, abbreviations, and other background technology related to LTE / EPS (Evolved Packet System) can refer to the 36.xxx series, 23.xxx series, and 24.xxx series, and terms, abbreviations, and other background technology related to NR (new radio) / 5GS can refer to the 38.xxx series, 23.xxx series, and 24.xxx series.

[0049] Hereinafter, this specification is described based on the terms defined above.

[0050] The three key requirement areas for 5G include (1) Enhanced Mobile Broadband (eMBB), (2) Massive Machine Type Communication (mMTC), and (3) Ultra-reliable and Low Latency Communications (URLLC).

[0051] Some use cases may require optimization across multiple domains, while others may focus on just one Key Performance Indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.

[0052] Communication system applicable to the present disclosure

[0053] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the present disclosure disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0054] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0055] Figure 1 illustrates an example of a communication system applied to the present disclosure.

[0056] Referring to FIG. 1, a communication system (100) applied to the present disclosure includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (extended reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI (artificial intelligence) device / server (100g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicles (100b-1, 100b-2) may include unmanned aerial vehicles (UAVs) (e.g., drones). The XR devices (100c) include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. The portable devices (100d) may include smartphones, smart pads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.), etc. The home appliances (100e) may include TVs, refrigerators, washing machines, etc. The IoT devices (100f) may include sensors, smart meters, etc. For example, the base station (120) and the network (130) may also be implemented as wireless devices, and a specific wireless device (120a) may act as a base station / network node to other wireless devices.

[0057] Wireless devices (100a to 100f) can be connected to a network (130) via a base station (120). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (100g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (120) / network (130), but can also communicate directly (e.g., sidelink communication) without going through the base station (120) / network (130). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). In addition, IoT devices (100f) (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0058] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base stations (120), and base stations (120) / base stations (120). Here, the wireless communication / connection can be established through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and base station-to-base station communication (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and base station / wireless device, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of the present disclosure, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc. may be performed.

[0059] Figure 2 illustrates an example of a UE applicable to the present disclosure.

[0060] Referring to FIG. 2, the UE (200) may include a processor (202), memory (204), a transceiver (206), one or more antennas (208), a power management module (241), a battery (242), a display (243), a keypad (244), a SIM (Subscriber Identification Module) card (245), a speaker (246), and a microphone (247).

[0061] The processor (202) may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein. The processor (202) may be configured to control one or more other components of the UE (200) to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein. A layer of a radio interface protocol may be implemented in the processor (202). The processor (202) may include an ASIC, other chipset, logic circuit, and / or data processing device. The processor (202) may be an application processor. The processor (202) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator).

[0062] Memory (204) is operatively coupled to the processor (202) and can store various information for operating the processor (202). Memory (204) may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When the implementation is implemented in software, the techniques described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed herein. The modules may be stored in memory (204) and executed by the processor (202). Memory (204) may be implemented within the processor (202) or external to the processor (202), in which case it may be communicatively coupled to the processor (202) via various methods known in the art.

[0063] A transceiver (206) is operably coupled to the processor (202) and is capable of transmitting and / or receiving wireless signals. The transceiver (206) may include a transmitter and a receiver. The transceiver (206) may include baseband circuitry for processing radio frequency signals. The transceiver (206) may control one or more antennas (208) to transmit and / or receive wireless signals.

[0064] The power management module (241) can manage the power of the processor (202) and / or the transceiver (206). The battery (242) can supply power to the power management module (241).

[0065] The display (243) can output the results processed by the processor (202). The keypad (244) can receive input to be used by the processor (202). The keypad (244) can be displayed on the display (243).

[0066] A SIM card (245) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and can be used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0067] The speaker (246) can output sound-related results processed by the processor (202). The microphone (247) can receive sound-related input to be used by the processor (202).

[0068] In implementations of this specification, a UE may operate as a transmitter in the uplink and as a receiver in the downlink. In implementations of this specification, a base station may operate as a receiver in the uplink and as a transmitter in the downlink. In this specification, a base station may be referred to as a Node B (Node B), an eNode B (eNB), or a gNB, and may not be limited to a specific form.

[0069] In addition, for example, the UE may be implemented in various forms depending on the use case / service. The UE may be composed of various components, devices / parts, and / or modules. For example, each UE may include a communication device, a control device, a memory device, and additional components. The communication device may include a communication circuit and a transceiver. For example, the communication circuit may include one or more processors and / or one or more memories. For example, the transceiver may include one or more transceivers and / or one or more antennas. The control device is electrically connected to the communication device, the memory device, and the additional components, and may control the overall operation of each UE. For example, the control device may control the electrical / mechanical operation of each UE based on a program / code / command / information stored in the memory device. The control device may transmit information stored in the memory device to an external device (e.g., another communication device) via the communication device via a wireless / wired interface, or may store information received from an external device (e.g., another communication device) via the communication device via a wireless / wired interface in the memory device.

[0070] Additional components may be configured in various ways depending on the type of UE. For example, the additional components may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a driving device, and a computing device. In addition, the UE is not limited thereto, and may be implemented in the form of a robot (100a in FIG. 1), a vehicle (100b-1 and 100b-2 in FIG. 1), an XR device (100c in FIG. 1), a portable device (100d in FIG. 1), a home appliance (100e in FIG. 1), an IoT device (100f in FIG. 1), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (100g in FIG. 1), a base station (120 in FIG. 1), or a network node. UE can be used in mobile or fixed locations depending on the use case / service.

[0071] The various components, devices / parts, and / or modules of the UE may all be connected to each other via a wired interface, or at least some of them may be connected wirelessly via a communication device. In addition, each component, device / part, and / or module of the UE may further include one or more elements. For example, the control device may be configured by a set of one or more processors. For example, the control device may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a graphics processing unit, and a memory control processor. As another example, the memory device may be configured by a random access memory (RAM), a dynamic random access memory (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0072]

[0073] 5G system architecture applicable to the present disclosure

[0074] The 5G system is an advanced technology from the 4th generation LTE mobile communication technology. It supports new radio access technology (RAT: Radio Access Technology), extended LTE (eLTE) as an extended technology of LTE (Long Term Evolution), and non-3GPP (e.g., WLAN) access through the evolution or clean-state structure of the existing mobile communication network structure.

[0075] 5G systems are defined as service-based, and the interactions between network functions (NFs) within the architecture for 5G systems can be expressed in two ways as follows.

[0076] - Reference point representation: Represents the interaction between NF services within NFs described by a point-to-point reference point (e.g., N11) between two NFs (e.g., AMF and SMF).

[0077] Service-based representation: Network functions (e.g., AMF) within the control plane (CP) allow other authorized network functions to access their services. This representation also includes point-to-point reference points, if necessary.

[0078] 5GC (5G Core) can include various components, some of which include access and mobility management function (AMF), session management function (SMF), policy control function (PCF), user plane function (UPF), application function (AF), unified data management (UDM), and non-3GPP interworking function (N3IWF).

[0079] The UE connects to the data network via the UPF via the next-generation radio access network (NG-RAN) that includes the gNB. The UE can receive data services via untrusted non-3GPP access points, such as wireless local area networks (WLANs). To connect non-3GPP access points to the core network, an N3IWF may be deployed.

[0080] The N3IWF manages interworking between non-3GPP access and 5G systems. When a UE is connected to a non-3GPP access (e.g., WiFi, also known as IEEE 802.11), it can connect to a 5G system via the N3IWF. The N3IWF performs control signaling with the AMF and connects to the UPF via the N3 interface for data transmission.

[0081] AMF can manage access and mobility in 5G systems. It can also manage non-access stratum (NAS) security. It can also handle mobility in idle states.

[0082] The UPF functions as a gateway for transmitting and receiving user data. A UPF node can perform all or part of the user plane functions of a 4G mobile communications S-GW (serving gateway) and P-GW (packet data network gateway).

[0083] The UPF acts as a boundary between the next generation RAN (NG-RAN) and the core network, and is an element that maintains the data path between the gNB and the SMF. In addition, the UPF acts as a mobility anchor point when the UE moves across the area served by the gNB. The UPF can perform the function of handling PDUs. For mobility within the NG-RAN (e.g., NG-RAN defined after 3GPP Release-15), the UPF can route packets. In addition, the UPF can also act as an anchor point for mobility with other 3GPP networks (e.g., RAN defined before 3GPP Release-15), such as UTRAN (UMTS (universal mobile telecommunications system) terrestrial radio access network), E-UTRAN (evolved-UTRAN), or GERAN (GSM (global system for mobile communication) / EDGE (enhanced data rates for global evolution) radio access network). A UPF may correspond to the termination point of a data interface toward a data network.

[0084] The PCF is a node that controls the operator's policies. The AF is a server that provides various services to UEs. The UDM is a server that manages subscriber information, similar to the HSS (home subscriber server) of 4G mobile communications. The UDM (460) stores and manages subscriber information in a unified data repository (UDR).

[0085] The SMF can perform the function of assigning an IP (Internet protocol) address to the UE. In addition, the SMF can control the PDU (protocol data unit) session.

[0086] For convenience of explanation below, the drawing symbols for AMF, SMF, PCF, UPF, AF, UDM, N3IWF, gNB, or UE may be omitted, and operation may be performed by referring to the matters described in standard documents published prior to this document.

[0087] Figure 3 illustrates an example of functional separation of NG-RAN and 5GC (5th generation core) applicable to the present disclosure.

[0088] Referring to Figure 3, the UE connects to a data network (DN) via a next-generation RAN. The control plane function (CPF) node performs all or part of the functions of the mobility management entity (MME) of 4G mobile communications, and all or part of the control plane functions of the serving gateway (S-GW) and the PDN gateway (P-GW). The CPF node includes the AMF and the SMF.

[0089] The UPF node functions as a gateway through which user data is transmitted and received.

[0090] The authentication server function (AUSF) authenticates and manages UEs. The Network Slice Selection Function (NSSF) is a node for network slicing, as described below.

[0091] The network exposure function (NEF) provides a mechanism to securely expose the services and functions of the 5G core.

[0092] The reference points shown in Fig. 3 are as follows. N1 represents a reference point between the UE and the AMF. N2 represents a reference point between the (R)AN and the AMF. N3 represents a reference point between the (R)AN and the UPF. N4 represents a reference point between the SMF and the UPF. N5 represents a reference point between the PCF and the AF. N6 represents a reference point between the UPF and the DN. N7 represents a reference point between the SMF and the PCF. N8 represents a reference point between the UDM and the AMF. N9 represents a reference point between the UPFs. N10 represents a reference point between the UDM and the SMF. N11 represents a reference point between the AMF and the SMF. N12 represents a reference point between the AMF and the AUSF. N13 represents a reference point between the UDM and the AUSF. N14 represents a reference point between the AMFs. N15 represents a reference point between a PCF and an AMF in a non-roaming scenario, and a reference point between an AMF and a PCF of a visited network in a roaming scenario. N16 represents a reference point between SMFs. N22 represents a reference point between an AMF and an NSSF. N30 represents a reference point between a PCF and an NEF. N33 may represent a reference point between an AF and an NEF, and the entities and interfaces described above may be configured with reference to those described in standard documents published before this document. N58 represents a reference point between an AMF and an NSSAAF. N59 represents a reference point between a UDM and an NSSAAF. N80 represents a reference point between an AMF and an NSACF. N81 represents a reference point between an SMF and an NSACF.

[0093] The radio interface protocol is based on the 3GPP radio access network standard. Horizontally, the radio interface protocol consists of the physical layer, data link layer, and network layer. Vertically, it is divided into the user plane for data information transmission and the control plane for control signaling.

[0094] Protocol layers can be divided into L1 (layer-1), L2 (layer-2), and L3 (layer-3) based on the three lower layers of the open systems interconnection (OSI) standard model, which is widely known in communication systems.

[0095] Below, the present disclosure describes each layer of the wireless protocol. Figure 4 illustrates an example of a general architecture of a 5G (5th generation) system applicable to the present disclosure.

[0096] Referring to FIG. 4, the AS (access stratum) layer may include a physical (PHY) layer, a medium access control layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer, and operations based on each layer may be performed by referring to matters described in standard documents published prior to this document.

[0097] Referring to 3GPP TR 23.700-41, various approaches are being studied to address the challenges inherent in network slice architecture. [Table 1] highlights the research scopes focused on in this disclosure among the various areas of research to improve network slices.

[0098]

[0099] Key issues and solutions for the scope shown in [Table 1] have been discussed. In particular, key issue #6 (KI#6) relates to improved network control of terminal operations, and as a solution to this, a method using an inactivity timer for a network slice established on demand has been proposed. For example, if there is no PDU session using the network slice established on demand, the registration for the network slice is deactivated using the inactivity timer. At this time, the inactivity timer is set for each S-NSSAI and runs on both the terminal and the AMF. In addition, the timer is provided by the HPLMN or VPLMN during the registration procedure together with the set NSSAI. In the present disclosure, the inactivity timer is an inactivity timer for network slice deregistration, and may be referred to as a slice deregistration inactivity timer, or a network slice deregistration inactivity timer.

[0100] Referring to 3GPP TS 23.501, a method for controlling the use of network slices using an inactivity timer is defined. Table 2 below shows the network slice use control method extracted from 3GPP TS 23.501.

[0101]

[0102] Referring to [Table 2], AMF starts a slice deregistration inactivity timer per access type and S-NSSAI to deregister a network slice when the network slice is not used in any PDU session. The slice deregistration inactivity timer is stopped and reset when one or more PDU sessions associated with the network slice are successfully established or the S-NSSAI for the network slice is removed from the allowed NSSAIs.

[0103] 3GPP CT1 (Core Network and Terminals 1) discusses the mobility management aspect of network slice usage control functions. According to CT1, to control network slice usage, the AMF maintains or manages a slice deregistration inactivity timer for each on-demand S-NSSAI. In addition, to deregister a network slice, the AMF removes the corresponding S-NSSAI from the allowed NSSAIs and notifies the UE of a new allowed NSSAI with the removed S-NSSAI. The states of the slice deregistration inactivity timer and on-demand S-NSSAI on the AMF side are always treated as baselines, regardless of the states of the slice deregistration inactivity timer and on-demand S-NSSAI on the UE side. Here, the on-demand S-NSSAI refers to the S-NSSAI that allows the UE to register with the network. In other words, it is the S-NSSAI that the UE uses to establish a PDU session for user data transmission, and the UE is registered with the network based on the corresponding on-demand S-NSSAI.

[0104] [Table 3] is a mobility management-based network slice usage control scheme extracted from 3GPP TS 24.501.

[0105]

[0106] Referring to [Table 3], AMF monitors network slice usage by executing a slice deregistration inactivity timer by S-NSSAI and access type when there is no associated PDU session for a certain period of time. At this time, when the slice deregistration inactivity timer expires, AMF sends a configuration update command message with the allowed NSSAI to the terminal to remove the corresponding S-NSSAI from the terminal's allowed NSSAI.

[0107] 3GPP TS 24.501 defines various functions of NWDAF. For example, NWDAF supports data collection functions from NF and AF, data collection functions from OAM, and provisioning of analytics information for NF and AF. In addition, NWDAF supports various NF services. For example, NWDAF provides the Nnwdaf_AnalyticsSubscription service, which allows NF service consumers to subscribe to and / or unsubscribe from various types of analytics of NWDAF, or the Nnwdaf_AnalyticsInfo service, which allows NF service consumers to request various types of analytics information from NWDAF or NWDAFs to request analytics context transfer to other NWDAFs. [Table 4] is a definition of analytics subscription and / or unsubscription by NWDAF service consumers extracted from 3GPP TS 23.288, and FIG. 5 shows the network data analytics subscription and / or unsubscription procedure.

[0108]

[0109] Referring to [Table 4] and FIG. 5, the NWDAF service consumer (520) sends a subscription and / or unsubscription message to the Nnwdaf_AnalyticsSubscription service to NWDAF (520) to receive notifications about analysis information.

[0110]

[0111] NWDAF analyzes network data related to slice load levels and provides slice load level information to consumer network functions. [Table 5] presents a network data analysis method related to slice load levels, extracted from 3GPP TS 23.288.

[0112]

[0113]

[0114] NWDAF collects information as shown in [Table 6] and [Table 7] to analyze network data related to slice load levels. [Table 6] shows data input from OAM for slice load analysis, and [Table 7] shows data input from 5GC NF for slice load analysis.

[0115] InformationSourceDescriptionUE registered in a Network Slice / Network Slice instanceOAMMean number of UEs registered in a NW slice or NW slice instance as defined in TS 28.552 [8]. (NOTE 1).PDU Session established on a Network Slice / Network Slice instanceOAMMean number of established PDU Sessions in a NW slice or NW slice instance as defined in TS 28.552 [8]. (NOTE 1).Load of NFs associated to Network Slice instanceOAMResource utilization information of a Network Slice instance obtained from its constituent NF instances. NF instance load input data collection is described in clause 6.5, Table 6.5.2-1.NOTE 1: 5GC performance measurements can be provided per S-NSSAI by OAM as defined in TS 28.552 [8]. Any 5GC performance measurements per NSI ID required further coordination with SA WG5.

[0116] InformationSourceDescriptionTimestamps5GC NFA time stamp associated with the collected information.UE registers / de-registers to a Network Slice / Network Slice instanceAMF(s)AMF reports that a UE registered or deregistered to a S-NSSAI or to a S-NSSAI and NSI ID.Number of UEs served by the AMFAMF(s)AMF reports the total number of UEs served by the AMF per S-NSSAI or per S-NSSAI and NSI ID. (NOTE 1)PDU Session established / released on a Network SliceSMF(s)SMF reports that a PDU Session is established or released per S-NSSAI or per S-NSSAI and NSI ID.Current number of UEs registered in a NW sliceNSACFNSACF reports the number of UE registered at the S-NSSAI.Current number of PDU Sessions established in a NW sliceNSACFNSACF reports the number of PDU Sessions established at the S-NSSAI.Load of NFs associated to Network Slice instanceNRFResource utilization information of a Network Slice instance obtained from its constituent NF instances.NF instance load input data collection is described in clause 6.5, Table 6.5.2-1.NOTE 1: AMF reports the total number of registered UE in the AMF at each associated time stamp.NOTE 2: SMF reports multiple PDU Sessions when establishment or release happened at the same time, indicated by the time stamp.NOTE 3: Based on the internal logic, the NWDAF determines the source for the data collection.

[0117]

[0118] As described above, NWDAF obtains and provides analysis information related to network load based on the collected information. For example, NWDAF provides analysis information related to network load, as shown in [Tables 8] to [Tables 11].

[0119] [Table 8] shows the network slice instance load statistics of NWDAF.

[0120] InformationDescriptionS-NSSAIIdentification of the Network Slice.Network Slice instances (1..max)List of Network Slice instance(s) within the S-NSSAI.> NSI IDIdentification of the Network Slice instance.> Number of UE Registrations (NOTE 1)Number of UE registrations of the Network Slice instance (average, variance).> Number of PDU Sessions establishment (NOTE 1)Number of PDU Session establishments of the Network Slice instance (average, variance).> Resource usage (NOTE 1)The usage of assigned virtual resources currently in use for the NF instances (mean usage of virtual CPU, memory, disk) as defined in clause 5.7 of TS 28.552 [8], belonging to a particular Network Slice instance.> Resource usage threshold crossings (NOTE 1)Number of times resource usage threshold is met or exceeded or crossed on the Network Slice instance and the time when it happened. It is present if threshold is provided by the consumer as Analytics Filter.> Resource usage threshold crossings time period (1..max) (NOTE 1, NOTE 2)Resource usage threshold crossing vector including time elapsed between times each threshold is met or exceeded or crossed on the Network Slice instance if a threshold value is provided by the consumer as Analytics Filter.> Load Level (NOTE 1)The load level of the Network Slice Instance indicated by the S-NSSAI and the associated NSI ID (if applicable) in the Analytics Filter, it is present if Load Level Threshold is not provided by the consumer as Analytics Filter.> Crossed Load Level Threshold (NOTE 1)An indication on whether the Load Level Threshold is met or exceeded by the statistics value of the Load Level. It is present if the Load Level Threshold is provided by the consumer as Analytics Filter.NOTE 1: Analytics subset that can be used in "list of analytics subsets that are requested".NOTE 2: The time period is a time interval specified by a start time and an end time timestamps within the Analytics target period.

[0121] [표 9]는 네트워크 슬라이스 부하 통계 정보를 나타낸다.

[0122] InformationDescriptionS-NSSAIIdentification of the Network Slice.> Number of UE Registrations (NOTE 1)Number of UE registrations at the Network Slice (average, variance).> Number of PDU sessions establishments (NOTE 1)Number of PDU Session establishments at the Network Slice (average, variance).> Load Level (NOTE 1)The load level of the Network Slice Instance indicated by the S-NSSAI and the associated NSI ID (if applicable) in the Analytics Filter, it is present if Load Level Threshold is not provided by the consumer as Analytics Filter.> Crossed Load Level Threshold (NOTE 1)An indication on whether the Load Level Threshold is met or exceeded by the statistics value of the Load Level. It is present if the Load Level Threshold is provided by the consumer as Analytics Filter.NOTE 1: Analytics subset that can be used in "list of analytics subsets that are requested".

[0123] [표 10]은 네트워크 슬라이스 인스턴스 부하 예측 정보를 나타낸다.

[0124] InformationDescriptionS-NSSAIIdentification of the Network Slice.Network Slice instances (1..max)List of Network Slice instance(s) within the S-NSSAI.> NSI IDIdentification of the Network Slice instance.> Number of UE Registrations (NOTE 1)Number of predicted UE registrations at the Network Slice instance (average, variance).> Number of PDU Sessions establishment (NOTE 1)Number of predicted PDU Session establishments of the Network Slice instance (average, variance).> Resource usage (NOTE 1)The predicted usage of assigned virtual resources for the NF instances (mean usage of virtual CPU, memory, disk) as defined in clause 5.7 of TS 28.552 [8], belonging to a particular Network Slice instance.> Resource usage threshold crossings (NOTE 1)Number of predicted times resource usage threshold is met or exceeded or crossed at the Network Slice instance and the time when it happened. It is present if a threshold value is provided by the consumer as Analytics Filter.> Resource usage threshold crossings time period (1..max) (NOTE 1, NOTE 2)Predicted Resource usage threshold vector including predicted time elapsed between times each threshold is met or exceeded or crossed on the Network Slice instance, it is present if a threshold value is provided by the consumer as Analytics Filter.> Load Level (NOTE 1)The load level of the Network Slice Instance indicated by the S-NSSAI and the associated NSI ID (if applicable) in the Analytics Filter, if Load Level Threshold is not provided by the consumer as Analytics Filter.> Crossed Load Level Threshold (NOTE 1)An indication on whether the Load Level Threshold is met or exceeded by the predicted value of the Load Level. It is present if the Load Level Threshold is provided by the consumer as Analytics Filter.> ConfidenceConfidence of this prediction.NOTE 1: Analytics subset that can be used in "list of analytics subsets that are requested".NOTE 2: The time period is a time interval specified by a start time and an end time timestamps within the Analytics target period.

[0125] [Table 11] shows network slice load prediction information.

[0126] InformationDescriptionS-NSSAIIdentification of the Network Slice.> Number of UE Registrations (NOTE 1)Predicted Number of UE registrations at the Network Slice (average, variance).> Number of PDU sessions establishments (NOTE 1)Predicted Number of PDU Session establishments at the Network Slice (average, variance).> Load Level (NOTE 1)The load level of the Network Slice Instance indicated by the S-NSSAI and the associated NSI ID (if applicable) in the Analytics Filter, if Load Level Threshold is not provided by the consumer as Analytics Filter.> Crossed Load Level Threshold (NOTE 1)An indication of whether the Load Level Threshold is met or exceeded by the predicted value of the Load Level. It is present if the Load Level Threshold is provided by the consumer as Analytics Filter.> ConfidenceConfidence of this prediction.NOTE 1: Analytics subset that can be used in "list of analytics subsets that are requested".

[0127]

[0128] 본 발명의 구체적인 실시예

[0129] The present disclosure relates to setting a slice deregistration inactivity timer in a wireless communication system. Specifically, the present disclosure relates to a device and method for adjusting a slice deregistration inactivity timer value based on information periodically exchanged between an access and mobility management function (AMF) and an NWDAF. In the present disclosure, an AMF is a network node performing an AMF function, and includes an AMF node or an AMF entity, and an NWDAF is a network node performing an NWDAF function, and includes an NWDAF node or an NWDAF entity.

[0130] Currently, the 3GPP SA2 / CT1 (system aspects 2 / core network and terminals 1) WG (working group) has defined S-NSSAI, which performs slice registration only when a terminal uses an actual slice while executing an application in eNS_Ph3 (enhancement of network slicing phase 3), as on-demand single network slice selection assistance information (on-demand S-NSSAI). In addition, the 3GPP SA2 / CT1 WG has defined a slice deregistration inactivity timer to effectively use on-demand S-NSSAI, and is studying a method to prevent unnecessary use of resources by deregistering slices for on-demand S-NSSAIs assigned to or associated with PDU session(s) for which user data traffic is no longer generated. In particular, for the execution of the slice deregistration inactivity timer, a method is being discussed in which the network determines whether to use the slice deregistration inactivity timer and then transmits the value of the slice deregistration inactivity timer to the terminal, thereby executing, starting, or driving the slice deregistration inactivity timer in each of the terminal and the network.

[0131] The network uses a slice deregistration inactivity timer to control that the S-NSSAI is used only when the terminal actually uses the S-NSSAI.

[0132] FIG. 6 illustrates an example of a slice deregistration inactivity timer execution procedure. Referring to FIG. 6, in step S601, a terminal (UE) (610) and an AMF (620) perform a registration procedure for initial registration of the terminal. Thereafter, in step S603, the terminal (610) transmits a registration request message including an on-demand S-NSSAI to the AMF (620). In step S605, the AMF (620) transmits to the terminal (610) an allowed NSSAI and a timer value. Here, the timer value includes a slice deregistration inactivity timer value and is set for the on-demand S-NSSAI based on local information such as information received from the PCF or UDM and network load. Accordingly, each of the MF (620) and the terminal (610) can store the value of the slice deregistration inactivity timer for the on-demand S-NSSAI. In step S607, the AMF (620) and the terminal (610) perform a PDU session establishment procedure. Thereafter, in step S609, the AMF (630) transmits a PDU session release message to the terminal. In step S611, if there is no PDU session using the corresponding on-demand S-NSSAI, each of the AMF (620) and the terminal (610) executes a slice deregistration inactivity timer for the on-demand S-NSSAI. Thereafter, when the slice deregistration inactivity timer expires, each of the AMF (620) and the terminal (610) deletes or removes the corresponding on-demand S-NSSAI from the allowed NSSAI.

[0133] However, the timing at which the slice deregistration inactivity timer for an on-demand S-NSSAI in the AMF expires and the timing at which the slice deregistration inactivity timer for an on-demand S-NSSAI expires in the terminal may not match. In this case, the timing at which the on-demand S-NSSAI is deleted from the allowed NSSAIs stored in the network and the terminal may be different, which may cause unnecessary signaling between the terminal and the network. For example, if the network's slice deregistration inactivity timer expires before the terminal's slice deregistration inactivity timer, the network deletes the on-demand S-NSSAI from the allowed NSSAIs stored in the network and suspends the service for the S-NSSAI. At this time, the terminal's slice deregistration inactivity timer may not have expired yet, so the on-demand S-NSSAI may still be included in the allowed NSSAIs stored in the terminal. In this case, the terminal may request PDU session establishment for the S-NSSAI. However, the network rejects the terminal's request because it has stopped servicing the S-NSSAI.

[0134] As mentioned above, if the expiration time of the network's slice deregistration inactivity timer for on-demand S-NSSAI and the expiration time of the terminal's slice deregistration inactivity timer do not match, unnecessary signaling occurs between the terminal and the network. Therefore, to prevent this, the slice deregistration inactivity timer must be set precisely.

[0135] Therefore, the present disclosure proposes a method for more accurately setting a slice deregistration inactivity timer by utilizing NWDAF, which monitors network load, AMF load, and usage failure reports between a network and a terminal. Here, the network load refers to load information generated between a terminal and the network, and the AMF load refers to load information generated in the AMF. In addition, the usage failure report is information reported from the AMF to the NWDAF when a terminal requests the use of an NSSAI that has already been deleted from the AMF among the allowed NSSAIs.

[0136] NWDAF is a network technology introduced by 3GPP in the 5G service-based architecture to support intelligent and autonomous network operation and service management. NWDAF includes network nodes or network entities that collect data from various modules of the 5G system (e.g., NF, AF, UDR, etc.) and decide on network operation and management actions based on the collected data. For example, NWDAF performs various functions such as calculating and predicting load levels for network slices, analyzing and predicting specific network functions, calculating network load performance, and predicting future loads. Currently, the data format for transmitting data related to S-NSSAI in AMF and / or NWDAF is not defined, and because AMF and / or NWDAF do not separately collect information about signaling between the network and terminals, the currently collected information alone is not suitable for setting a slice deregistration inactivity timer for on-demand S-NSSAI.

[0137] Accordingly, the present disclosure proposes a method for AMF to receive network load, usage failure report information, and AMF load information for on-demand S-NSSAI from NWDAF, and to precisely set or adjust the value of a slice deregistration inactivity timer based on the received information.

[0138] The NWDAF receives information about network load, AMF load, and usage failure reports from the AMF, and derives or predicts at least one of the network load, AMF load, and the number of usage failure reports for the S-NSSAI using empirical values ​​based on statistics of the received information. The NWDAF transmits analysis data including at least one of the network load, AMF load, and the number of usage failure reports for the S-NSSAI derived or predicted for a specific period of time to the AMF. Such interaction between the AMF and the NWDAF is performed periodically.

[0139] The AMF sets the slice deregistration inactivity timer value of the corresponding terminal based on the analysis data received from the NWDAF, and transmits the slice deregistration inactivity timer value of the terminal to the terminal using a registration accept message or a UE configuration update command message. In other words, the AMF updates the slice deregistration inactivity timer values ​​of the AMF and the terminal based on information updated through periodic interaction with the NWDAF, i.e., analysis data. When the slice deregistration inactivity timer value of the terminal is updated, the AMF transmits a registration accept message or a UE configuration update command message including the updated slice deregistration inactivity timer value to the terminal. Through this, the terminal can receive, store, and set the updated slice deregistration inactivity timer value.

[0140] When a PDU session release event occurs for a terminal, the AMF sends a PDU session release message to the terminal. When the last PDU session associated with the on-demand S-NSSAI is released, the AMF executes, starts, or drives the configured AMF slice deregistration inactivity timer. In addition, the terminal executes, starts, or drives the configured terminal slice deregistration inactivity timer when it receives a PDU session release message for the last PDU session associated with the on-demand S-NSSAI from the AMF.

[0141] FIG. 7 illustrates an example of a procedure for executing an AMF slice deregistration inactivity timer according to one embodiment of the present disclosure. FIG. 7 illustrates a method performed by a network node. The network node includes an AMF.

[0142] Referring to Figure 7, in step S701, the network node receives a registration request message. In other words, the network node receives a registration request message containing an on-demand S-NSSAI from the terminal. In one embodiment, the registration request message may further include terminal capability information. Upon receiving the registration request message, the network node may perform an operation for terminal registration.

[0143] In step S703, the network node transmits a registration acceptance message. In other words, the network node transmits a registration acceptance message to the terminal in response to the terminal's registration request message. The registration acceptance message includes an allowed NSSAI and a timer value. Here, the allowed NSSAI includes an on-demand S-NSSAI included in the registration request message, and the timer value includes a slice deregistration inactivity timer value for the on-demand S-NSSAI. The slice deregistration inactivity timer value for the on-demand S-NSSAI can be determined based on information received from the PCF and UDM or acquired from the NWDAF. The information acquired from the NWDAF can include at least one of a network load, an AMF load, and a number of usage failure reports for the S-NSSAI.

[0144] In step S705, the network node establishes a PDU session. In other words, the network node can establish a PDU session between the network node and the terminal by receiving a PDU session establishment request message from the terminal and sending a PDU session establishment acceptance message to the terminal. At this time, the PDU session may be a session using on-demand S-NSSAI.

[0145] In step S707, the network node transmits a PDU session release message. When a PDU session termination event occurs, the network node transmits a PDU session release message to the terminal for PDU session termination.

[0146] In step S709, the network node starts a slice deregistration inactivity timer. That is, the network node starts a slice deregistration inactivity timer associated with a slice for the terminal. The slice deregistration inactivity timer associated with a slice for the terminal may be referred to as a slice deregistration inactivity timer for an on-demand S-NSSAI. The value of the slice deregistration inactivity timer for an on-demand S-NSSAI may be determined based on information received from the PCF and the UDM or obtained from the NWDAF. For example, the AMF may obtain analysis data including at least one of network load, AMF load, and number of usage failure reports for the on-demand S-NSSAI through periodic interaction with the NWDAF, and may set or update the value of the slice deregistration inactivity timer for the on-demand S-NSSAI based on the obtained analysis data. After the network node transmits a PDU session release message, if the PDU session for the S-NSSAI no longer exists, the network node starts the slice deregistration inactivity timer. Afterwards, when the slice deregistration inactivity timer for the on-demand S-NSSAI expires, the network node locally deletes the on-demand S-NSSAI from the allowed NSSAI list.

[0147] FIG. 8 illustrates an example of a procedure for executing a slice deregistration inactivity timer of a terminal according to one embodiment of the present disclosure. FIG. 8 illustrates a method performed by a terminal.

[0148] Referring to Figure 8, in step S801, the terminal transmits a registration request message. In other words, the terminal transmits a registration request message containing an on-demand S-NSSAI to the network node. In one embodiment, the registration request message may further include terminal capability information.

[0149] In step S803, the terminal receives a registration acceptance message from the network node. In other words, the terminal receives a registration acceptance message from the network node in response to a registration request message. The registration acceptance message includes an allowed NSSAI and a timer value. Here, the allowed NSSAI includes the on-demand S-NSSAI included in the registration request message, and the timer value includes a slice deregistration inactivity timer value for the on-demand S-NSSAI. The slice deregistration inactivity timer value for the on-demand S-NSSAI may be a value received by the AMF from the PCF and UDM, or a value determined by the AMF based on information obtained from the NWDAF.

[0150] In step S805, the terminal establishes a PDU session. A PDU session between the terminal and the network node can be established by the terminal sending a PDU session establishment request message to the network node, and the network node sending a PDU session establishment acceptance message to the terminal.

[0151] In step S807, the terminal receives a PDU session release message. That is, the terminal receives a PDU session release message for terminating the PDU session from the network node.

[0152] In step S809, the terminal starts a slice deregistration inactivity timer. In other words, the terminal can execute a slice deregistration inactivity timer for an on-demand S-NSSAI when a PDU session release message is received. The value of the slice deregistration inactivity timer for an on-demand S-NSSAI can be received via a registration acceptance message or a terminal configuration update command message. When the slice deregistration inactivity timer for an on-demand S-NSSAI expires, the terminal locally deletes the on-demand S-NSSAI from the allowed NSSAI list.

[0153] FIG. 9 illustrates an example of a procedure for setting a slice deregistration inactivity timer according to one embodiment of the present disclosure. FIG. 9 illustrates a method performed by AMF.

[0154] Referring to FIG. 9, in step S901, the AMF transmits collected data to the NWDAF. In other words, the AMF collects data necessary for analyzing network data related to the load of on-demand S-NSSAI for a certain period of time and transmits the collected data to the NWDAF. For example, the AMF may collect data necessary for analyzing network data related to the load of on-demand S-NSSAI by measuring, calculating, or collecting at least one of information on terminals using on-demand S-NSSAI, network load, AMF load, number of terminals being processed by the AMF, number of terminals using on-demand S-NSSAI, number of usage requests per terminal for on-demand S-NSSAI, and number of usage requests per on-demand S-NSSAI. The collected data may be referred to as input data necessary for analyzing network data related to the load of on-demand S-NSSAI.

[0155] In step S903, the AMF receives analysis data from the NWDAF. The AMF receives analysis data indicating the results of analyzing network data related to the load of the on-demand S-NSSAI from the NWDAF. The analysis data may include at least one of the network load, AMF load, and the number of usage failure reports for the on-demand S-NSSAI.

[0156] In step S905, the AMF sets a timer based on the analysis data. In other words, the AMF sets a slice deregistration inactivity timer value for the on-demand S-NSSAI based on the analysis data received from the NWDAF. In one embodiment, the AMF may maintain or update the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI based on at least one of the network load and the number of usage failure reports included in the analysis data. In one embodiment, the AMF may maintain or update the slice deregistration inactivity timer value of the AMF for the on-demand S-NSSAI based on the AMF load included in the analysis data.

[0157] In step S907, the AMF checks whether the timer value of the terminal has changed. In step S905, the AMF checks whether the slice deregistration inactivity timer value of the terminal for on-demand S-NSSAI has changed as a result of setting the timer.

[0158] If the timer value of the terminal has changed, the AMF retransmits the timer value to the terminal in step S909. If the slice deregistration inactivity timer value of the terminal for on-demand S-NSSAI has changed, the AMF may transmit the changed slice deregistration inactivity timer value for on-demand S-NSSAI to the terminal using a registration acceptance message or a terminal configuration update command message.

[0159] As described with reference to FIG. 9, the AMF transmits input data necessary for analyzing network data related to on-demand S-NSSAI load to the NWDAF, and the NWDAF transmits analysis data, which is the result of analyzing the network data related to on-demand S-NSSAI load, to the AMF. Here, the input data may include information that can be obtained by the AMF through reception, measurement, or calculation over a certain period of time. For example, the input data may include information that enables the NWDAF to measure and analyze network load and AMF load, information that enables the NWDAF to derive statistics on failed reports between terminals and AMF, and information on the number of usage failure reports for each on-demand S-NSSAI. In addition, the output data may include information that can be obtained by the NWDAF through statistical analysis based on the input data. For example, the output data may include information on network load level, AMF load level, usage failure report of terminal, and on-demand S-NSSAI.

[0160] The present disclosure proposes data formats for transmitting input data and analysis data. Table 12 below shows the format of input data, and Table 13 below shows the format of analysis data. However, embodiments of the present disclosure are not limited thereto.

[0161] InformationSourceDescriptionTimestamps5GC NFA time stamp associated with the collected information.UE registers / de-registers to a Network Slice / Network Slice instanceAMF(s)AMF reports that a UE registered or deregistered to a S-NSSAI or to a S-NSSAI and NSI ID.Number of UEs served by the AMFAMF(s)AMF reports the total number of UEs served by the AMF per S-NSSAI or per S-NSSAI and NSI ID. (NOTE 1)On-demand S-NSSAIAMF(s)AMF reports the on-demand S-NSSAI.Network load of on-demand S-NSSAIAMF(s)AMF reports the network load input data about on-demand S-NSSAI.The usage failure reports about on-demand S-NSSAIAMF(s)AMF reports that requests to use the on-demand S-NSSAI after being deleted from allowed NSSAI per on-demand S-NSSAI.The usage failure reports about UE.AMF(s)AMF reports usage failure per the UE.

[0162] As defined in [Table 12], the input data may include at least one of a timestamp, whether a terminal is registered for a network slice / network slice instance, the number of terminals supported by AMF, on-demand S-NSSAI, network load of on-demand S-NSSAI, usage failure report for on-demand S-NSSAI, and usage failure report for terminal.

[0163] InformationDescriptionOn-demand S-NSSAIIidentification of the On-demand Network Slice.On-demand Network Slice instances (1..max)List of Network Slice instance(s) within the on-demand S-NSSAI.Network load levelThe average load of the network over the Analytics target period.The number of usage failure reportsThe number of usage failure reports.AMF load levelThe average load of the AMF over the Analytics target period.

[0164] As defined in [Table 13], the analysis data may include at least one of on-demand S-NSSAI, on-demand network slice instances, network load level, number of usage failure reports, and AMF load level.

[0165]

[0166] FIG. 10 illustrates a signaling example for setting a slice deregistration inactivity timer according to one embodiment of the present disclosure.

[0167] Referring to FIG. 10, in step S1001, a terminal (UE) (1010) and an AMF (1020) perform a registration procedure. That is, the terminal (1010) and the AMF (1020) perform an initial registration procedure. Specifically, the terminal (1010) may transmit a registration request message for initial registration to the AMF (1020), and the AMF (1020) may transmit a registration acceptance message to the terminal (1010). The registration acceptance message may include an allowed NSSAI.

[0168] In step S1003, AMF (1020) transmits input data to NWDAF (1030). In other words, AMF (1020) can collect input data required to analyze network data related to the load of on-demand S-NSSAI for a certain period of time and transmit the collected input data to NWDAF (1030). The input data can include at least one of a timestamp, whether a terminal is registered for a network slice / network slice instance, the number of terminals supported by AMF, on-demand S-NSSAI, network load of on-demand S-NSSAI, usage failure report for on-demand S-NSSAI, and usage failure report for terminal, as shown in [Table 12]. The input data can be transmitted to NWDAF (1030) at each occurrence of a specified event or at each specified cycle.

[0169] In step S1005, the terminal (1010) transmits a registration request message to the AMF (1020). In other words, the terminal (1010) transmits a registration request message including an on-demand S-NSSAI to the AMF (1020) to set an on-demand S-NSSAI. The on-demand S-NSSAI may be determined based on at least one of the allowed NSSAI and a service required by the running application of the terminal (1010). When the registration request message is received, the AMF (1020) may perform an operation for registering the terminal (1010). For example, the AMF (1020) may set a network slice for the terminal (1010) based on the on-demand S-NSSAI included in the registration request message.

[0170] In step S1007, the AMF (1030) transmits a registration acceptance message to the terminal (1010). The registration acceptance message includes an allowed NSSAI and a timer value. Here, the allowed NSSAI includes the on-demand S-NSSAI included in the registration request message, and the timer value includes a slice deregistration inactivity timer value for the on-demand S-NSSAI. At this time, the slice deregistration inactivity timer value for the on-demand S-NSSAI may be a value received from the PCF and UDM.

[0171] Meanwhile, in step S1009, NWDAF (1030) analyzes network data related to the on-demand S-NSSAI. In other words, NWDAF (1030) can obtain analysis data by analyzing network data related to the on-demand S-NSSAI based on input data.

[0172] In step S1011, NWDAF (1030) transmits analysis data to AMF (1020). The analysis data may include at least one of an on-demand S-NSSAI, an on-demand network slice instance, a network load level, a number of usage failure reports, and an AMF load level, as defined in [Table 13].

[0173] In step S1013, AMF (1020) sets a timer. In other words, AMF (1020) sets or updates the terminal and AMF slice deregistration inactivity timer value for on-demand S-NSSAI based on the analysis data received from NWDAF (1030).

[0174] In step S1015, AMF (1020) transmits input data to NWDAF (1030). In other words, AMF (1020) can collect input data necessary to analyze network data related to the load of on-demand S-NSSAI for a certain period of time after step S1003, and transmit the collected input data to NWDAF (1030).

[0175] In step S1017, AMF (1020) transmits a terminal configuration update command message to terminal (1010). In other words, AMF (1020) transmits a terminal configuration update command message to terminal (1010) that includes the terminal's slice deregistration inactivity timer value for allowed NSSAI and on-demand S-NSSAI.

[0176] In step S1019, the terminal (1010) and the AMF (1020) perform a PDU session establishment procedure. Specifically, the terminal (1010) transmits a PDU session establishment request message to the AMF (1020), and the AMF (1020) transmits a PDU session establishment acceptance message to the terminal (1010), whereby a PDU session between the AMF (1020) and the terminal (1010) can be established.

[0177] Meanwhile, in step S1021, NWDAF (1030) transmits analysis data to AMF (1020). That is, NWDAF (1030) transmits analysis data acquired based on input data in step S1015 to AMF (1020). The analysis data has a data format as defined in [Table 13].

[0178] In step S1023, AMF (1020) sets a timer. In other words, AMF (1020) maintains or updates the terminal and AMF slice deregistration inactivity timer value for on-demand S-NSSAI based on the analysis data received from NWDAF (1030).

[0179] In step S1025, AMF (1020) transmits a PDU session release message to terminal (1010). When a PDU session termination event occurs, AMF (1020) transmits a PDU session release message for PDU session termination to terminal (1010).

[0180] After transmitting the PDU session release message, in step S1027, the AMF (1020) executes a slice deregistration inactivity timer. That is, after transmitting the PDU session release message related to the on-demand S-NSSAI to the terminal, if it is detected that the PDU session using the on-demand S-NSSAI no longer exists, the AMF (1020) executes the AMF's slice deregistration inactivity timer for the on-demand S-NSSAI.

[0181] When a PDU session release message is received, in step S1029, the terminal (1010) executes a slice deregistration inactivity timer. That is, when a PDU session release message related to an on-demand S-NSSAI is received, the terminal (1010) determines that a PDU session using the on-demand S-NSSAI no longer exists, and executes the terminal's slice deregistration inactivity timer for the on-demand S-NSSAI.

[0182]

[0183] The operation of the terminal or AMF for controlling the use of network slices based on mobility management is defined as in [Table 14].

[0184]

[0185] According to [Table 14], the AMF provides the slice deregistration inactivity timer for each on-demand S-NSSAI to the UE through a registration acceptance message or a UE configuration update command message. In addition, when the UE initiates a PDU session establishment procedure associated with the on-demand S-NSSAI, it sends a registration request message including the corresponding on-demand S-NSSAI in the requested NSSAI IE. The AMF receives the slice deregistration inactivity timer value from the PCF or UDM, or determines the slice deregistration inactivity timer value based on the network data analysis result related to the on-demand S-NSSAI received from the NWDAF.

[0186]

[0187] FIG. 11 illustrates an example of a slice deregistration inactivity timer adjustment procedure according to one embodiment of the present disclosure. FIG. 11 illustrates a method performed by a network node. The network node includes an AMF. The operations of FIG. 11 can be understood as detailed operations of S905, S911, or S921 of FIG. 9.

[0188] Referring to FIG. 11, in step S1101, the network node determines whether at least one of the network load and the number of usage failure reports has changed. The network node determines whether at least one of the network load and the number of usage failure reports has changed by comparing the network load and the number of usage failure reports at the current time for the on-demand S-NSSAI with the network load and the number of usage failure reports at a previous time for the on-demand S-NSSAI. Here, the network load and the number of usage failure reports at the current time and the previous time may be the network load and the number of usage failure reports for the on-demand S-NSSAI that the AMF received from the NWDAF at the current time and the previous time.

[0189] If at least one of the network load and the number of usage failure reports has changed, in step S1103, the network node changes the timer value of the terminal. Here, the timer value of the terminal means the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI. According to one embodiment, if the network load at the current time point and the network load at the previous time point for the on-demand S-NSSAI are different, the network node may change the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI based on the amount of network load change for the on-demand S-NSSAI. For example, if the network load at the current time point for the on-demand S-NSSAI is less than the network load at the previous time point, the network node may decrease the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI by the amount of decreased network load. As another example, if the current network load for an on-demand S-NSSAI is greater than the network load for a previous time, the network node may increase the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI by the amount of increased network load.

[0190] According to one embodiment, if the number of usage failure reports at the current time point and the number of usage failure reports at the previous time point for an on-demand S-NSSAI are different, the network node may change the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI based on the change in the number of usage failure reports for the on-demand S-NSSAI. For example, if the number of usage failure reports at the current time point for the on-demand S-NSSAI is greater than the number of usage failure reports at the previous time point, the network node may increase the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI by the increased number.

[0191] If at least one of the network load and the number of usage failure reports has not changed, in step S1103, the network node maintains the timer value of the terminal. According to one embodiment, if the network load at the current time point and the network load at the previous time point for the on-demand S-NSSAI are the same, the network node may maintain the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI. According to one embodiment, if the number of usage failure reports at the current time point and the number of usage failure reports at the previous time point are the same, the network node may maintain the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI.

[0192] At step S1107, the network node determines whether the AMF load has changed. The network node determines whether the AMF load has changed by comparing the AMF load at the current time point with the AMF load at a previous time point for the on-demand S-NSSAI. Here, the AMF load at the current time point and the previous time point may be the AMF load for the on-demand S-NSSAI received by the AMF from the NWDAF at the current time point and the previous time point.

[0193] If the AMF load has changed, in step S1109, the network node changes the timer values ​​of the terminal and the AMF. Here, the timer values ​​of the terminal and the AMF mean the slice deregistration inactivity timer value of the terminal and the slice deregistration inactivity timer value of the AMF for the on-demand S-NSSAI. According to one embodiment, if the AMF load of the current time point and the AMF load of the previous time point are different for the on-demand S-NSSAI, the network node may change the slice deregistration inactivity timer value of the terminal and the slice deregistration inactivity timer value of the AMF for the on-demand S-NSSAI based on the amount of AMF load change for the on-demand S-NSSAI. For example, if the AMF load of the current time point for the on-demand S-NSSAI is less than the AMF load of the previous time point, the network node may decrease the slice deregistration inactivity timer value of the terminal and the slice deregistration inactivity timer value of the AMF for the on-demand S-NSSAI by the amount of decreased AMF load. As another example, if the current AMF load for an on-demand S-NSSAI is greater than the AMF load for a previous time, the network node may increase the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI and the slice deregistration inactivity timer value of the AMF by the amount of increased AMF load.

[0194] If the AMF load has not changed, in step S1111, the network node maintains the timer value of the AMF. According to one embodiment, if the current AMF load for the on-demand S-NSSAI and the previous AMF load are the same, the network node may maintain the slice deregistration inactivity timer value of the terminal for the on-demand S-NSSAI and the slice deregistration inactivity timer value of the AMF.

[0195] As described above, the AMF according to the embodiment of the present disclosure updates the slice deregistration inactivity timer value using the NWDAF and transmits the updated timer value to the terminal. At this time, the AMF can adjust the slice deregistration inactivity timer value using an algorithm (e.g., the algorithm described with reference to FIG. 11) based on information analyzed from the NWDAF. In addition, the NWDAF can analyze information about on-demand S-NSSAI received from the AMF, network load, AMF load, and missed signals between the terminal and the AMF, and provide the AMF with analysis data having a new data format for the on-demand S-NSSAI.

[0196] It is clear that the examples of the proposed methods described above can also be considered as a type of proposed methods, as they can be included as one of the implementation methods of the present disclosure. Furthermore, the proposed methods described above can be implemented independently, but they can also be implemented in the form of a combination (or merge) of some of the proposed methods. Information regarding the applicability of the proposed methods (or information regarding the rules of the proposed methods) can be defined by a rule such that the base station notifies the terminal of the application of the proposed methods through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0197] The present disclosure may be embodied in other specific forms without departing from the technical ideas and essential features described herein. Therefore, the above detailed description should not be construed as limiting in all respects but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are intended to be included within the scope of the present disclosure. Furthermore, claims that do not explicitly cite each other in the claims may be combined to form embodiments or incorporated into new claims through post-filing amendments.

[0198] Embodiments of the present disclosure can be applied to various wireless access systems. Examples of various wireless access systems include the 3rd Generation Partnership Project (3GPP) or 3GPP2 systems.

[0199] The embodiments of the present disclosure can be applied not only to the various wireless access systems described above, but also to all technical fields that utilize these various wireless access systems. Furthermore, the proposed method can also be applied to mmWave and THz communication systems utilizing ultra-high frequency bands.

[0200] Additionally, embodiments of the present disclosure can be applied to various applications such as autonomous vehicles and drones.

Claims

1. A method performed by a network node in a wireless communication system, A step of receiving a first message requesting registration from a terminal; A step of transmitting a second message accepting registration to the terminal; A step of establishing a PDU (protocol data unit) session for the above terminal; a step of transmitting a third message indicating release of the PDU session; and A step of starting a slice deregistration inactivity timer related to a slice for the terminal, A method in which the value of the above slice deregistration inactivity timer is determined based on information obtained using a network data analytics function (NWDAF) node.

2. In claim 1, A method wherein the above network node includes an AMF (access and mobility management function) node.

3. In claim 2, A method in which information obtained using the NWDAF node includes at least one of a network load occurring between the terminal and the network, an AMF load occurring at the AMF node, and a number of usage failure reports indicating that a request has occurred for an NSSAI that has already been deleted from the AMF node among the allowed NSSAIs.

4. In claim 3, A step of periodically transmitting input data necessary for analyzing network data related to a slice for the terminal to the NWDAF; A step of receiving analysis data indicating the result of analyzing network data related to the slice for the terminal from the NWDAF; and A method further comprising the step of updating the value of the slice deregistration inactivity timer based on the received analysis data.

5. In claim 4, A method wherein the input data comprises at least one of a timestamp, whether the terminal is registered for a network slice or a network slice instance, the number of terminals supported by the AMF, an on-demand S-NSSAI indicating a slice for the terminal, a network load for the on-demand S-NSSAI, a usage failure report for the on-demand S-NSSAI, and a usage failure report for the terminal.

6. In claim 4, A method wherein the analysis data comprises at least one of an on-demand S-NSSAI indicating a slice for the terminal, network slice instances within the on-demand S-NSSAI, a network load level, a number of usage failure reports, and an AMF load level.

7. In claim 4, A method in which the value of the above-mentioned updated slice deregistration inactivity timer is transmitted to the terminal via the above-mentioned registration acceptance message or terminal configuration update command message.

8. In claim 3, The step of updating the value of the above slice deregistration inactivity timer is: A method comprising the step of adjusting the value of a slice deregistration inactivity timer to be transmitted to the terminal based on at least one of the network load and the number of usage failure reports.

9. In claim 3, The step of updating the value of the above slice deregistration inactivity timer is: A method comprising the step of adjusting a slice deregistration inactivity timer value to be transmitted to the terminal and a slice deregistration inactivity timer value of the AMF based on the AMF load.

10. In a method performed by a terminal in a wireless communication system, A step of transmitting a first message requesting registration to a network node; A step of receiving a second message accepting registration from the network node; A step of establishing a PDU (protocol data unit) session for the terminal and the network; receiving a third message from the network node indicating release of the PDU session; and A step of starting a slice deregistration inactivity timer related to a slice for the terminal, A method in which the value of the above slice deregistration inactivity timer is determined based on information obtained from an NWDAF (network data analytics function) node in an AMF (access and mobility management function) node.

11. In a network node in a wireless communication system, Transmitter and receiver; and A processor connected to the above transmitter and receiver is included, The above processor, Receive a first message requesting registration from the terminal, Send a second message accepting registration to the terminal, Establish a PDU (protocol data unit) session for the above terminal, Send a third message indicating the release of the above PDU session, Starts a slice deregistration inactivity timer related to the slice for the above terminal, A network node whose value of the above slice deregistration inactivity timer is determined based on information obtained using a network data analytics function (NWDAF) node.

12. In a wireless communication system, at a terminal, Transmitter and receiver; and A processor connected to the above transmitter and receiver is included, The above processor, Send a first message requesting registration to a network node, Receive a second message accepting registration from the above network node, Establish a PDU (protocol data unit) session for the above terminal and network, Receive a third message from the network node indicating release of the PDU session, Starts a slice deregistration inactivity timer related to the slice for the above terminal, The value of the above slice deregistration inactivity timer is determined based on information obtained from the NWDAF (network data analytics function) node in the AMF (access and mobility management function) node.

13. In communication devices, At least one processor; At least one computer memory connected to said at least one processor and storing instructions that direct operations when executed by said at least one processor, The above actions are, A step of transmitting a first message requesting registration to a network node; A step of receiving a second message accepting registration from the network node; A step of establishing a PDU (protocol data unit) session for the terminal and the network; receiving a third message from the network node indicating release of the PDU session; and A step of starting a slice deregistration inactivity timer related to a slice for the terminal, A communication device in which the value of the above slice deregistration inactivity timer is determined based on information obtained from an NWDAF (network data analytics function) node in an AMF (access and mobility management function) node.

14. In a non-transitory computer-readable medium storing at least one instruction, comprising at least one instruction executable by the processor, At least one of the above commands causes the device to: Receive a first message requesting registration from the terminal, Send a second message accepting registration to the terminal, Establish a PDU (protocol data unit) session for the above terminal, Send a third message indicating the release of the above PDU session, Starts a slice deregistration inactivity timer related to the slice for the above terminal, A computer-readable medium in which the value of the above slice deregistration inactivity timer is determined based on information obtained using a network data analytics function (NWDAF) node.

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