Slice replacement and use control management method

Abstract

One disclosure of the present specification provides a method. The method comprises the steps in which: on the basis that a slice deregistration timer related to replaced S-NSSAI or alternative S-NSSAI has expired, a UE deletes the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAI; and, on the basis of the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAI, the UE deletes an entry including the replaced S-NSSAI or the alternative S-NSSAI from alternative NSSAI, wherein the alternative S-NSSAI is S-NSSAI switched from the replaced S-NSSAI by network slice replacement.

Description

How to manage slice replacement and usage control

[0001] This specification relates to mobile communications.

[0002] 3GPP (3rd Generation Partnership Project) LTE (Long-Term Evolution) is a technology designed to enable high-speed packet communications. Numerous approaches have been proposed to achieve LTE's goals of reducing costs for users and operators, improving service quality, expanding coverage, and increasing system capacity. 3GPP LTE's high-level requirements include reduced cost per bit, improved service availability, flexible use of frequency bands, a simple architecture, open interfaces, and adequate power consumption for terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work on developing requirements and specifications for new radio (NR) systems. 3GPP must identify and develop the technical components necessary to successfully standardize NR in a timely manner, meeting both urgent market needs and the longer-term requirements outlined by the ITU-R (ITU radio communication sector) International Mobile Telecommunications (IMT)-2020 process. NR must also be able to utilize any spectrum band up to at least 100 GHz, ensuring that it remains available for wireless communications well into the future.

[0004] NR aims to be a single technology framework that addresses all deployment scenarios, usage scenarios, and requirements, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable and low latency communications (URLLC). NR must be inherently forward-compatible.

[0005] When a replaced S-NSSAI or an alternate S-NSSAI is deleted from the allowed NSSAI based on the timer expiration, the entry containing the replaced S-NSSAI or the alternate S-NSSAI is deleted from the alternate NSSAI.

[0006] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0007] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0008] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0009] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0010] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0011] Figures 6 and 7 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0012] Figures 8 and 9 illustrate examples of a PDU session establishment procedure to which the implementation of the present specification applies.

[0013] Figure 10 is an example diagram showing an example of an architecture for implementing the concept of network slicing.

[0014] Figure 11 is an example diagram showing another example of an architecture for implementing the concept of network slicing.

[0015] Figure 12 illustrates an example of an alternative NSSAI information element.

[0016] Figure 13 shows an example of an entry.

[0017] Figure 14 illustrates an example of an on-demand NSSAI information element.

[0018] Figure 15 shows an example of on-demand S-NSSAI information.

[0019] Figure 16 shows an example where slice replacement occurs for on-demand S-NSSAI.

[0020] Figure 17 illustrates the UE's procedure for disclosure of this specification.

[0021] Figure 18 illustrates the AMF's procedure for the disclosure of this specification.

[0022] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multicarrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented via wireless technologies such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be implemented via wireless technologies such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented using wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or E-UTRA (evolved UTRA). UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long-term evolution) is part of E-UMTS (evolved UMTS) that uses E-UTRA.3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolution of 3GPP LTE includes LTE-A (advanced), LTE-A Pro, and / or 5G NR (new radio).

[0023] For convenience of explanation, the implementation of this specification is primarily described in relation to a 3GPP-based wireless communication system. However, the technical features of this specification are not limited thereto. For example, the following detailed description is provided based on a mobile communication system corresponding to a 3GPP-based wireless communication system. However, aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0024] For terms and technologies used in this specification that are not specifically described, reference may be made to wireless communication standard documents published prior to this specification.

[0025] As used herein, "A or B" can mean "only A," "only B," or "both A and B." Alternatively, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0026] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0027] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0028] Additionally, in this specification, “at least one of A, B and C” can mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C”.

[0029] Additionally, parentheses used herein may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in this specification is not limited to "PDCCH," and "PDCCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0030] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0031] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein may be applied to various fields requiring wireless communication and / or connectivity between devices (e.g., 5G).

[0032] Hereinafter, the present specification will be described in more detail with reference to the drawings. In the following drawings and / or description, the same reference numbers may refer to the same or corresponding hardware blocks, software blocks, and / or functional blocks, unless otherwise indicated.

[0033] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0034] The 5G usage scenario shown in FIG. 1 is only an example, and the technical features of this specification can be applied to other 5G usage scenarios not shown in FIG. 1.

[0035] The three main requirement categories for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC).

[0036] Referring to FIG. 1, a communication system (1) includes wireless devices (100a to 100f), a base station (BS; 200), and a network (300). FIG. 1 illustrates a 5G network as an example of a network of the communication system (1), but the implementation of the present disclosure is not limited to a 5G system and can be applied to future communication systems beyond the 5G system.

[0037] The base station (200) and the network (300) may be implemented as wireless devices, and a particular wireless device may operate as a base station / network node in relation to other wireless devices.

[0038] Wireless devices (100a to 100f) refer to devices that perform communication using radio access technology (RAT) (e.g., 5G NR or LTE) and may also be referred to as communication / wireless / 5G devices. Wireless devices (100a to 100f) may include, but are not limited to, robots (100a), vehicles (100b-1 and 100b-2), extended reality (XR) devices (100c), portable devices (100d), home appliances (100e), IoT devices (100f), and artificial intelligence (AI) devices / servers (400). For example, vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR / VR / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs) and heads-up displays (HUDs) mounted on vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signs, vehicles, robots, etc. Portable devices may include smartphones, smart pads, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0039] In this specification, wireless devices (100a to 100f) may be referred to as user equipment (UE). The UE may include, for example, a mobile phone, a smartphone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving functions, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a holographic device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a weather / environmental device, a 5G service-related device, or a 4th industrial revolution-related device.

[0040] For example, a UAV may be an aircraft that is unmanned and navigated by radio control signals.

[0041] For example, a VR device may include a device for implementing objects or backgrounds in a virtual environment. For example, an AR device may include a device that implements objects or backgrounds in a virtual world by connecting them to objects or backgrounds in the real world. For example, an MR device may include a device that implements objects or backgrounds in a virtual world by merging them with objects or backgrounds in the real world. For example, a holographic device may include a device that implements 360-degree stereoscopic images by recording and reproducing three-dimensional information using the light interference phenomenon that occurs when two laser lights, called holograms, meet.

[0042] For example, a public safety device may include an image relay device or imaging device that can be worn on the user's body.

[0043] For example, MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation. Examples include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0044] For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, curing, or preventing a disease. For example, a medical device may be a device used for diagnosing, treating, alleviating, or correcting an injury or damage. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying a structure or function. For example, a medical device may be a device used for the purpose of regulating pregnancy. For example, a medical device may include a therapeutic device, a driving device, an (in vitro) diagnostic device, a hearing aid, or a surgical device.

[0045] For example, a security device may be a device installed to prevent potential hazards and maintain safety. For example, a security device may be a camera, closed-circuit television (CCTV), a recorder, or a black box.

[0046] For example, a fintech device may be a device capable of providing financial services, such as mobile payments. For example, a fintech device may include a payment device or a point-of-sale system.

[0047] For example, a weather / environment device may include a device that monitors or predicts the weather / environment.

[0048] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). 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 (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a network after 5G. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station (200) / network (300). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0049] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) and / or between wireless devices (100a to 100f) and a base station (200) and / or between base stations (200). Here, the wireless communication / connection can be established through various RATs (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or, device-to-device (D2D) communication), and base station-to-base station communication (150c) (e.g., relay, integrated access and backhaul (IAB)). Through the wireless communication / connection (150a, 150b, 150c), the wireless devices (100a to 100f) and the base station (200) can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of the 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.), and resource allocation processes can be performed based on various proposals of the present specification.

[0050] AI is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0051] A robot can be defined as a machine that automatically processes or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making decisions, and performing actions on its own can be called an intelligent robot. Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with a drive unit, including an actuator or motor, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots include wheels, brakes, and propellers in their drive unit, enabling them to drive on the ground or fly in the air.

[0052] Autonomous driving refers to the technology of driving on one's own, while autonomous vehicles refer to vehicles that drive without, or with minimal, user intervention. For example, autonomous driving can include technologies such as lane keeping, automatic speed control like adaptive cruise control, autonomous driving along a set route, and autonomous driving based on a set destination. Vehicles encompass all types of vehicles: those with internal combustion engines, hybrid vehicles with both internal combustion engines and electric motors, and electric vehicles with only electric motors. These vehicles can include not only cars but also trains and motorcycles. Autonomous vehicles can be viewed as robots with autonomous driving capabilities.

[0053] Extended reality is a general term for VR, AR, and MR. VR technology provides real-world objects and backgrounds as CG images only, AR technology provides virtual CG images over images of real objects, and MR technology is a CG technology that mixes and combines virtual objects with the real world. MR technology is similar to AR in that it displays real and virtual objects together. However, there is a difference: while AR uses virtual objects to complement real objects, MR uses virtual and real objects equally.

[0054] NR supports multiple numerologies, or subcarrier spacing (SCS), to support diverse 5G services. For example, an SCS of 15 kHz supports wide areas in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0055] The NR frequency band can be defined by two types of frequency ranges (FR1 and FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in NR systems, FR1 can mean the "sub-6GHz range," and FR2 can mean the "above 6GHz range," which can be referred to as millimeter wave (mmW).

[0056] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0057] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band from 410 MHz to 7125 MHz, as shown in Table 2 below. That is, FR1 may include frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include unlicensed bands. Unlicensed bands can be used for various purposes, such as for communications for vehicles (e.g., autonomous driving).

[0058] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0059] Here, the wireless communication technology implemented in the wireless device of the present specification may include not only LTE, NR, and 6G, but also narrowband IoT (NB-IoT) for low-power communication. For example, NB-IoT technology may be an example of LPWAN (low power wide area network) technology and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced MTC). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-bandwidth limited), 5) LTE-MTC, 6) LTE MTC, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification can include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PAN (personal area networks) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0060] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0061] In FIG. 2, the first wireless device (100) and / or the second wireless device (200) may be implemented in various forms depending on the use case / service. For example, {the first wireless device (100) and the second wireless device (200)} may correspond to at least one of {the wireless devices (100a to 100f) and the base station (200)}, {the wireless devices (100a to 100f) and the wireless devices (100a to 100f)}, and / or {the base station (200) and the base station (200)} of FIG. 1. The first wireless device (100) and / or the second wireless device (200) may be configured by various components, devices / parts, and / or modules.

[0062] The first wireless device (100) may include at least one transceiver, such as a transceiver (106), at least one processing chip, such as a processing chip (101), and / or one or more antennas (108).

[0063] The processing chip (101) may include at least one processor, such as a processor (102), and at least one memory, such as a memory (104). Additionally and / or alternatively, the memory (104) may be located external to the processing chip (101).

[0064] The processor (102) may control the memory (104) and / or the transceiver (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (102) may process information in the memory (104) to generate first information / signal and transmit a wireless signal including the first information / signal via the transceiver (106). The processor (102) may receive a wireless signal including second information / signal via the transceiver (106) and store information obtained by processing the second information / signal in the memory (104).

[0065] A memory (104) may be operatively connected to the processor (102). The memory (104) may store various types of information and / or instructions. The memory (104) may store firmware and / or software code (105) that implements code, instructions and / or sets of instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may implement instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more protocols. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more air interface protocol layers.

[0066] Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). Each transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (radio frequency) unit. In the present specification, the first wireless device (100) may represent a communication modem / circuit / chip.

[0067] The second wireless device (200) may include at least one transceiver, such as a transceiver (206), at least one processing chip, such as a processing chip (201), and / or one or more antennas (208).

[0068] The processing chip (201) may include at least one processor, such as a processor (202), and at least one memory, such as a memory (204). Additionally and / or alternatively, the memory (204) may be located external to the processing chip (201).

[0069] The processor (202) may control the memory (204) and / or the transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. For example, the processor (202) may process information in the memory (204) to generate third information / signal and transmit a wireless signal including the third information / signal via the transceiver (206). The processor (202) may receive a wireless signal including fourth information / signal via the transceiver (206) and store information obtained by processing the fourth information / signal in the memory (204).

[0070] A memory (204) may be operatively connected to the processor (202). The memory (204) may store various types of information and / or instructions. The memory (204) may store firmware and / or software code (205) that implements instruction codes, commands and / or sets of instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may implement instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more protocols. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more air interface protocol layers.

[0071] Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). Each transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with the RF unit. In the present specification, the second wireless device (200) may represent a communication modem / circuit / chip.

[0072] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). One or more processors (102, 202) may generate one or more protocol data units (PDUs), one or more service data units (SDUs), messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0073] The one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, and / or a microcomputer. The one or more processors (102, 202) may be implemented by hardware, firmware, software, and / or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), and / or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors (102, 202). For example, the one or more processors (102, 202) may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphic processing unit (GPU), and a memory control processor.

[0074] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), erasable programmable ROM (EPROM), flash memory, volatile memory, nonvolatile memory, hard drive, register, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0075] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, wireless signals, etc., to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, wireless signals, etc. from one or more other devices.

[0076] One or more transceivers (106, 206) may be coupled to one or more antennas (108, 208). Additionally and / or alternatively, one or more transceivers (106, 206) may include one or more antennas (108, 208). One or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein via one or more antennas (108, 208). In the present specification, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0077] One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or a filter. For example, one or more transceivers (106, 206) may up-convert an OFDM baseband signal to an OFDM signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202) and transmit the up-converted OFDM signal at a carrier frequency. One or more transceivers (106, 206) may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202).

[0078] Although not illustrated in FIG. 2, the wireless device (100, 200) may further include additional components. The additional components (140) may be configured in various ways depending on the type of the wireless device (100, 200). For example, the additional components (140) 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. The additional components (140) may be connected to one or more processors (102, 202) via various technologies, such as a wired or wireless connection.

[0079] In the implementation of the present specification, a UE can operate as a transmitter in the uplink (UL) and as a receiver in the downlink (DL). In the implementation of the present specification, a base station can operate as a receiver in the UL and as a transmitter in the DL. For the sake of convenience of description, it is mainly assumed below that the first wireless device (100) operates as a UE and the second wireless device (200) operates as a base station. For example, a processor (102) connected to, mounted on, or released in the first wireless device (100) can be configured to perform UE operations according to the implementation of the present specification or to control a transceiver (106) to perform UE operations according to the implementation of the present specification. A processor (202) connected to, mounted on, or released in the second wireless device (200) can be configured to perform base station operations according to the implementation of the present specification or to control a transceiver (206) to perform base station operations according to the implementation of the present specification.

[0080] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0081] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0082] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0083] The UE (100) includes a processor (102), memory (104), a transceiver (106), one or more antennas (108), a power management module (141), a battery (142), a display (143), a keypad (144), a SIM (Subscriber Identification Module) card (145), a speaker (146), and a microphone (147).

[0084] The processor (102) may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. The processor (102) may be configured to control one or more other components of the UE (100) 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 (102). The processor (102) may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor (102) may be an application processor. The processor (102) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator). An example of the processor (102) is the SNAPDRAGON manufactured by Qualcomm®. TM Series processors, EXYNOS made by Samsung® TM Series processors, A-series processors made by Apple®, HELIO made by MediaTek® TM ATOM series processors made by Intel® TM It can be found in the series processors or the corresponding next-generation processors.

[0085] Memory (104) is operatively coupled to the processor (102) and stores various information for operating the processor (102). Memory (104) 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 (104) and executed by the processor (102). Memory (104) may be implemented within the processor (102) or external to the processor (102), in which case it may be communicatively coupled to the processor (102) via various methods known in the art.

[0086] A transceiver (106) is operably coupled to the processor (102) and transmits and / or receives a radio signal. The transceiver (106) includes a transmitter and a receiver. The transceiver (106) may include a baseband circuit for processing a radio frequency signal. The transceiver (106) controls one or more antennas (108) to transmit and / or receive a radio signal.

[0087] The power management module (141) manages the power of the processor (102) and / or the transceiver (106). The battery (142) supplies power to the power management module (141).

[0088] The display (143) outputs the results processed by the processor (102). The keypad (144) receives input to be used by the processor (102). The keypad (144) can be displayed on the display (143).

[0089] A SIM card (145) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and is used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0090] The speaker (146) outputs sound-related results processed by the processor (102). The microphone (147) receives sound-related input to be used by the processor (102).

[0091] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0092] 5GC (5G Core) may include various components, and in FIG. 5, some of them include AMF (Access and Mobility Management Function) (410), SMF (Session Management Function) (420), PCF (Policy Control Function) (430), UPF (User Plane Function) (440), AF (Application Function) (450), UDM (Unified Data Management) (460), and N3IWF (Non-3GPP (3rd Generation Partnership Project) Inter Working Function) (490).

[0093] The UE (100) is connected to a data network via UPF (440) through a Next Generation Radio Access Network (NG-RAN) including a gNB (20).

[0094] The UE (100) can also receive data services via untrusted non-3GPP access, such as a Wireless Local Area Network (WLAN). To connect the non-3GPP access to the core network, an N3IWF (490) may be deployed.

[0095] The illustrated N3IWF (490) performs the function of managing interworking between non-3GPP access and 5G system. When UE (100) is connected to non-3GPP access (e.g., WiFi, referred to as IEEE 801.11), UE (100) can be connected to 5G system through N3IWF (490). N3IWF (490) performs control signaling with AMF (410) and is connected to UPF (440) through N3 interface for data transmission.

[0096] The illustrated AMF (410) can manage access and mobility in a 5G system. The AMF (410) can perform functions to manage Non-Access Stratum (NAS) security. The AMF (410) can perform functions to handle mobility in the idle state.

[0097] The illustrated UPF (440) is a type of gateway through which user data is transmitted and received. The UPF node (440) can perform all or part of the user plane functions of the S-GW (Serving Gateway) and P-GW (Packet Data Network Gateway) of 4th generation mobile communications.

[0098] The UPF (440) acts as a boundary point between the next generation radio access network (NG-RAN) and the core network, and is an element that maintains a data path between the gNB (20) and the SMF (420). In addition, when the UE (100) moves across the area served by the gNB (20), the UPF (440) acts as a mobility anchor point. The UPF (440) can perform a function of handling PDUs. For mobility within the NG-RAN (Next Generation-Radio Access Network defined after 3GPP Release-15), the UPF can route packets. Additionally, the UPF (440) may also function as an anchor point for mobility with other 3GPP networks (RANs defined before 3GPP Release-15, e.g., UTRAN, E-UTRAN (Evolved-UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network)) or GERAN (GSM (Global System for Mobile Communication) / EDGE (Enhanced Data rates for Global Evolution) Radio Access Network). The UPF (440) may correspond to a termination point of a data interface toward a data network.

[0099] The illustrated PCF (430) is a node that controls the business operator's policy.

[0100] The illustrated AF (450) is a server for providing various services to the UE (100).

[0101] The illustrated UDM (460) is a type of server that manages subscriber information, such as the HSS (Home Subscriber Server) of 4th generation mobile communications. The UDM (460) stores and manages the subscriber information in a Unified Data Repository (UDR).

[0102] The illustrated SMF (420) can perform the function of allocating an IP (Internet Protocol) address of the UE. In addition, the SMF (420) can control a PDU (protocol data unit) session.

[0103] For reference, the drawing symbols for AMF (410), SMF (420), PCF (430), UPF (440), AF (450), UDM (460), N3IWF (490), gNB (20), or UE (100) may be omitted below.

[0104] 5G mobile communications support multiple numerologies, or subcarrier spacing (SCS), to support diverse 5G services. For example, a 15 kHz SCS supports wide areas in traditional cellular bands. A 30 kHz / 60 kHz SCS supports dense urban environments, lower latency, and wider carrier bandwidth. An SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0105] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0106] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0107] - AUSF (Authentication Server Function)

[0108] - AMF (Access and Mobility Management Function)

[0109] - DN (Data Network), 예를 들어 운영자 서비스, 인터넷 접속 또는 타사 서비스

[0110] - USDF (Unstructured Data Storage Function)

[0111] - NEF (Network Exposure Function)

[0112] - I-NEF (Intermediate NEF)

[0113] - NRF (Network Repository Function)

[0114] - NSSF (Network Slice Selection Function)

[0115] - PCF (Policy Control Function)

[0116] - SMF (Session Management Function)

[0117] - UDM (Unified Data Management)

[0118] - UDR (Unified Data Repository)

[0119] - UPF (User Plane Function)

[0120] - UCMF (UE radio Capability Management Function)

[0121] - AF (Application Function)

[0122] - UE (User Equipment)

[0123] - (R)AN ((Radio) Access Network)

[0124] - 5G-EIR (5G-Equipment Identity Register)

[0125] - NWDAF (Network Data Analytics Function)

[0126] - CHF (CHarging Function)

[0127] Additionally, the following network features may be considered:

[0128] - N3IWF (Non-3GPP InterWorking Function)

[0129] - TNGF (Trusted Non-3GPP Gateway Function)

[0130] - W-AGF (Wireline Access Gateway Function)

[0131] Figure 5 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0132] For clarity of the point-to-point diagram in Figure 5, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0133] For clarity, the connection between UDR and other NFs (e.g., PCF) is not shown in Fig. 4. For clarity, the connection between NWDAF and other NFs (e.g., PCF) is not shown in Fig. 4.

[0134] The 5G system architecture includes the following benchmarks:

[0135] - N1: Reference point between UE and AMF.

[0136] - N2: Reference point between (R)AN and AMF.

[0137] - N3: Reference point between (R)AN and UPF.

[0138] - N4: Reference point between SMF and UPF.

[0139] - N6: Reference point between UPF and data network.

[0140] - N9: Reference point between two UPFs.

[0141] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0142] - N5: Reference point between PCF and AF.

[0143] - N7: Reference point between SMF and PCF.

[0144] - N8: Reference point between UDM and AMF.

[0145] - N10: Reference point between UDM and SMF.

[0146] - N11: Reference point between AMF and SMF.

[0147] - N12: Reference point between AMF and AUSF.

[0148] - N13: Reference point between UDM and AUSF.

[0149] - N14: Reference point between two AMFs.

[0150] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0151] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0152] - N22: Reference point between AMF and NSSF.

[0153] In some cases, two NFs may need to be interconnected to serve a UE.

[0154] <Registration Procedure>

[0155] Describes the registration procedure. See section 4.2.2.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0156] Figures 6 and 7 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0157] A UE must register with the network to receive services, enable mobility tracking, and enable reachability. The UE initiates the registration process using one of the following registration types:

[0158] - Initial registration for 5GS; or

[0159] - mobility registration update; or

[0160] - Periodic registration update; or

[0161] - Emergency registration

[0162] The general registration procedures of Figures 6 and 7 apply to all registration procedures described above, but periodic registration updates do not need to include all parameters used in other registration procedures.

[0163] The general registration procedures of Figures 6 and 7 can also be used when registering for a 3GPP connection when the UE is already registered for a non-3GPP connection, and vice versa. Registering for a 3GPP connection when the UE is already registered for a non-3GPP connection scenario may require an AMF change.

[0164] First, the procedure of Fig. 6 is described.

[0165] (1) Step 1: The UE transmits a Registration Request message to the (R)AN. The Registration Request message corresponds to an AN message.

[0166] The registration request message may include AN parameters. For NG-RAN, the AN parameters include, for example, the 5G SAE temporary mobile subscriber identity (5G-S-TMSI) or the globally unique AMF ID (GUAMI), the selected public land mobile network (PLMN) ID (or PLMN ID and network identifier (NID)), and the requested network slice selection assistance information (NSSAI). The AN parameters also include an establishment cause. The establishment cause provides the reason for requesting establishment of an RRC connection. Whether and how the UE includes the requested NSSAI as part of the AN parameters depends on the value of the access stratum connection establishment NSSAI inclusion mode parameter.

[0167] A registration request message may include a registration type. The registration type indicates whether the UE wants to perform an initial registration (i.e., the UE is in RM-DEREGISTERED state), or a mobility registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because the UE moves, or the UE wants to update its capabilities or protocol parameters, or because the UE requests a change in the set of network slices it is allowed to use), or a periodic registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because the periodic registration update timer has expired), or an emergency registration (i.e., the UE is in restricted service state).

[0168] When a UE performs initial registration, the UE indicates its UE ID in the registration request message, listed in decreasing priority order.

[0169] i) If the UE has a valid evolved packet system (EPS) globally unique temporary identifier (GUTI), 5G-GUTI mapped from the EPS GUTI;

[0170] ii) Native 5G-GUTI (if available) allocated by the PLMN in which the UE is attempting to register;

[0171] iii) Native 5G-GUTI allocated by a PLMN equivalent to the PLMN in which the UE is attempting to register;

[0172] iv) Native 5G-GUTI allocated by another PLMN (if available);

[0173] v) Otherwise, the UE includes a subscriber concealed identifier (SUCI) in the registration request message.

[0174] If a UE performing initial registration has both a valid EPS GUTI and a native 5G-GUTI, the UE also indicates the native 5G-GUTI as an additional GUTI. If more than one native 5G-GUTI is available, the UE selects a 5G-GUTI from items (ii)-(iv) in decreasing priority order in the list above.

[0175] When the UE performs initial registration with native 5G-GUTI, the UE indicates the relevant GUAMI information in the AN parameters. When the UE performs initial registration with SUCI, the UE does not indicate the GUAMI information in the AN parameters.

[0176] For emergency registration, if the UE does not have a valid 5G-GUTI, the SUCI is included. If the UE does not have a subscriber permanent identifier (SUPI) and does not have a valid 5G-GUTI, the PEI (Permanent Equipment Identifier) ​​is included. Otherwise, the 5G-GUTI is included, indicating the last serving AMF.

[0177] The registration request message may also include security parameters, PDU session status, etc. Security parameters are used for authentication and integrity protection. The PDU session status indicates a previously established PDU session in the UE. When the UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the PDU session status indicates the PDU session currently established in the PLMN in the UE.

[0178] (2) Step 2: (R)AN selects AMF.

[0179] If 5G-S-TMSI or GUAMI is not included, or if 5G-S-TMSI or GUAMI does not indicate a valid AMF, the (R)AN selects an AMF based on the (R)AT and the requested NSSAI, if available.

[0180] When the UE is in CM-CONNECTED state, (R)AN can forward a registration request message to AMF based on the UE's N2 connection.

[0181] If the (R)AN cannot select an appropriate AMF, the (R)AN performs AMF selection by forwarding a registration request message to the AMF configured in the (R)AN.

[0182] (3) Step 3: (R)AN sends a registration request message to the new AMF. The registration request message corresponds to the N2 message.

[0183] The registration request message may contain all of the information and / or part of the information contained in the registration request message received from the UE described in step 1.

[0184] The registration request message may include an N2 parameter. When NG-RAN is used, the N2 parameter includes the selected PLMN ID (or PLMN ID and NID), location information and cell ID related to the cell where the UE is camping, and a UE context request indicating that a UE context including security information should be established in the NG-RAN. When NG-RAN is used, the N2 parameter also includes an establishment cause.

[0185] If the registration type indicated by the UE is periodic registration update, steps 4-19 described below may be omitted.

[0186] (4) Step 4: If the UE's 5G-GUTI is included in the registration request message and the serving AMF has changed since the last registration procedure, the new AMF may invoke the Namf_Communication_UEContextTransfer service operation to the previous AMF, including the full registration request non-access stratum (NAS) message to request the UE's SUPI and UE context.

[0187] (5) Step 5: The old AMF can respond to the new AMF for the Namf_Communication_UEContextTransfer call including the UE's SUPI and UE context.

[0188] (6) Step 6: If SUCI is not provided by the UE or not retrieved from the previous AMF, the new AMF may initiate an ID request procedure by sending an Identity Request message to request SUCI from the UE.

[0189] (7) Step 7: The UE may respond with an Identity Response message including the SUCI. The UE derives the SUCI using the provided public key of the home PLMN (HPLMN).

[0190] (8) Step 8: The new AMF may decide to initiate UE authentication by calling the AUSF. In this case, the new AMF selects the AUSF based on SUPI or SUCI.

[0191] (9) Step 9: Authentication / security can be established by UE, new AMF, AUSF and / or UDM.

[0192] (10) Step 10: If the AMF has changed, the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation to notify the old AMF that the UE registration with the new AMF is complete. If the authentication / security procedure fails, the registration is rejected and the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation with a reject indication reason code to the old AMF. The old AMF may continue as if the UE context transfer service operation was not received.

[0193] (11) Step 11: If the PEI was not provided by the UE or was not retrieved from the previous AMF, the new AMF may initiate the ID request procedure by sending an Identity Request message to the UE to retrieve the PEI. The PEI is transmitted encrypted, except when the UE performs emergency registration and cannot be authenticated.

[0194] (12) Step 12: Optionally, the new AMF can initiate ME ID checking by calling the N5g-eir_EquipmentIdentityCheck_Get service operation.

[0195] Now, the procedure of Fig. 7 following the procedure of Fig. 6 is described.

[0196] (13) Step 13: If step 14 below is performed, the new AMF can select a UDM based on SUPI, and the UDM can select a UDR instance.

[0197] (14) Step 14: New AMFs can be registered with UDM.

[0198] (15) Step 15: New AMF can select PCF.

[0199] (16) Step 16: The new AMF may optionally perform AM policy association establishment / modification.

[0200] (17) Step 17: The new AMF can send update / release SM context messages (e.g., Nsmf_PDUSession_UpdateSMContext and / or Nsmf_PDUSession_ReleaseSMContext) to the SMF.

[0201] (18) Step 18: If the new AMF and the old AMF are in the same PLMN, the new AMF may send a UE context modification request to the N3IWF / TNGF / W-AGF.

[0202] (19) Step 19: N3IWF / TNGF / W-AGF may send a UE context modification response to the new AMF.

[0203] (20) Step 20: After the new AMF receives the response message from N3IWF / TNGF / W-AGF in step 19, the new AMF can register with UDM.

[0204] (21) Step 21: The new AMF sends a Registration Accept message to the UE.

[0205] The new AMF sends the UE a Registration Accept message indicating that the registration request has been accepted. If the new AMF allocates a new 5G-GUTI, it includes the 5G-GUTI. If the UE is already in the RM-REGISTERED state through another connection to the same PLMN, the UE uses the 5G-GUTI received in the Registration Accept message for both registrations. If the Registration Accept message does not include a 5G-GUTI, the UE uses the 5G-GUTI assigned to the existing registration for the new registration. If the new AMF allocates a new registration area, it sends the registration area to the UE in the Registration Accept message. If the Registration Accept message does not include a registration area, the UE considers the previous registration area to be valid. Mobility Restrictions are included if mobility restrictions apply to the UE and the registration type is not emergency registration. The new AMF indicates the PDU sessions established for the UE in the PDU Session State. The UE locally removes internal resources associated with PDU sessions that are not marked as established in the received PDU Session State. When a UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the UE locally removes internal resources associated with PDU sessions in the current PLMN that are not marked as established in the received PDU session status. If PDU session status information is present in the Registration Accept message, the new AMF indicates the PDU session status to the UE.

[0206] The Allowed NSSAI provided in the Registration Accept message is valid for the registration area and applies to all PLMNs that have a tracking area included in the registration area. The Mapping of Allowed NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Allowed NSSAIs. The Mapping of Configured NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Configured NSSAI for the serving PLMN.

[0207] Additionally, optionally, the new AMF performs UE policy association establishment.

[0208] (22) Step 22: If the UE successfully updates itself, it can send a Registration Complete message to the new AMF.

[0209] The UE may send a registration complete message to the new AMF to confirm that a new 5G-GUTI has been allocated.

[0210] (23) Step 23: In case of registration via 3GPP connection, if the new AMF does not release the signaling connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN. In case of registration via non-3GPP connection, if the UE is in CM-CONTENED state on the 3GPP connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN.

[0211] (24) Step 24: AMF can perform information updates on UDM.

[0212] (25) Step 25: The UE may execute a network slice-specific authentication and authorization (NSSAA) procedure.

[0213] <PDU 세션 수립 절차>

[0214] Describes the PDU session establishment procedure. See Section 4.3.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0215] Figures 8 and 9 illustrate examples of a PDU session establishment procedure to which the implementation of the present specification applies.

[0216] Establishing a PDU session may involve:

[0217] - UE-initiated PDU session establishment procedure

[0218] - PDU session handover between 3GPP and non-3GPP initiated by UE

[0219] - PDU session handover from UE-initiated EPS to 5GS.

[0220] - Network-triggered PDU session establishment procedure

[0221] A PDU session may be associated with either (a) a single connection type at a given time, i.e., either a 3GPP connection or a non-3GPP connection, or (b) multiple connection types simultaneously, i.e., one 3GPP connection and one non-3GPP connection. A PDU session associated with multiple connection types is called a multi-access (MA) PDU session and may be requested by an access traffic steering, switching, splitting (ATSS) capable UE.

[0222] Figures 8 and 9 specify the procedure for establishing a PDU session associated with a single connection type at a given time.

[0223] In the procedures shown in Figures 8 and 9, it is assumed that the UE is already registered with the AMF, so unless the UE is emergency registered, the AMF has already retrieved the user subscription data from the UDM.

[0224] First, the procedure of Fig. 8 is explained.

[0225] (1) Step 1: To establish a new PDU session, the UE generates a new PDU session ID.

[0226] The UE initiates the PDU session establishment procedure requested by the UE by sending an NAS message containing a PDU session establishment request message within the N1 SM container. The PDU session establishment request message includes the PDU session ID, the requested PDU session type, the requested session and service continuity (SSC) mode, 5G SM capabilities, Protocol Configuration Options (PCO), the SM PDU DN Request Container, and the UE Integrity Protection Maximum Data Rate.

[0227] If the PDU session establishment is a request to establish a new PDU session, the request type is "Initial Request." If the request refers to an existing PDU session switching between a 3GPP connection and a non-3GPP connection, or a PDU session handover from an existing packet data network (PDN) connection in the EPC, the request type is "Existing PDU Session." If the PDU session establishment is a request to establish a PDU session for emergency services, the request type is "Emergency Request." If the request refers to an existing PDU session for emergency services switching between a 3GPP connection and a non-3GPP connection, or a PDU session handover from an existing PDN connection for emergency services in the EPC, the request type is "Existing Emergency PDU Session."

[0228] The UE includes the S-NSSAI from the allowed NSSAI of the current connection type. If a mapping of allowed NSSAIs (Mapping of Allowed NSSAIs) is provided to the UE, the UE provides both the S-NSSAI of the VPLMN (visited VPLMN) from the allowed NSSAIs and the corresponding S-NSSAI of the HPLMN from the mapping of allowed NSSAIs.

[0229] (2) Step 2: AMF selects an SMF. If the request type indicates "Initial Request" or the request is due to a handover from an EPS or other non-3GPP connection provided by an AMF, AMF stores the connection type of the PDU session as well as the association of S-NSSAI(s), data network name (DNN), PDU session ID, and SMF ID.

[0230] If the request type is "Initial Request" and the message also contains a previous PDU Session ID representing an existing PDU Session, AMF selects an SMF and stores the association of the new PDU Session ID, S-NSAI(s), and the selected SMF ID.

[0231] If the request type indicates "Existing PDU Session," AMF selects an SMF based on the SMF-ID received from the UDM. AMF updates the stored connection type for the PDU session.

[0232] If the request type indicates "Existing PDU Session", which refers to an existing PDU session moving between a 3GPP connection and a non-3GPP connection, and if the serving PLMN S-NSSAI of the PDU session is in the allowed NSSAI of the target connection type, the PDU session establishment procedure may be performed in the following cases:

[0233] - When the SMF ID and AMF corresponding to the PDU session ID belong to the same PLMN;

[0234] - If the SMF ID corresponding to the PDU session ID belongs to HPLMN;

[0235] Otherwise, AMF rejects the PDU session establishment request with an appropriate rejection cause.

[0236] AMF rejects requests from emergency-registered UEs whose request type does not indicate "Emergency Request" or "Existing Emergency PDU Session".

[0237] (3) Step 3: If the AMF is not associated with an SMF for the PDU session ID provided by the UE (e.g., when the request type indicates "Initial Request"), the AMF invokes the Create SM Context request procedure (e.g., Nsmf_PDUSession_CreateSMContext Request). If the AMF is already associated with an SMF for the PDU session ID provided by the UE (e.g., when the request type indicates "Existing PDU Session"), the AMF invokes the Update SM Context request procedure (e.g., Nsmf_PDUSession_UpdateSMContext Request).

[0238] The AMF transmits the S-NSSAI of the serving PLMN to the SMF from the allowed NSSAI. For a roaming scenario of local breakout (LBO), the AMF also transmits the corresponding S-NSSAI of the HPLMN to the SMF from the mapping of the allowed NSSAI.

[0239] The AMF ID is the UE's GUAMI, which uniquely identifies the AMF serving the UE. The AMF passes the PDU session ID along with the N1 SM container containing the PDU session establishment request message received from the UE. The GPSI (generic public subscription identifier) ​​is included if available to the AMF.

[0240] If a UE in limited service state is registered for emergency services without providing SUPI, the AMF provides PEI instead of SUPI. If a UE in limited service state is registered for emergency services while providing SUPI but is not authenticated, the AMF indicates that the SUPI is not authenticated. If the SMF does not receive a SUPI for the UE or if the AMF indicates that the SUPI is not authenticated, the UE is considered unauthenticated.

[0241] AMF can include a PCF ID in Nsmf_PDUSession_CreateSMContext. This PCFID identifies the home PCF (H-PCF) in non-roaming cases and the visited PCF (V-PCF) in LBO roaming cases.

[0242] (4) Step 4: If the session management subscription data for the S-NSSAI of the corresponding SUPI, DNN, or HPLMN is not available, the SMF can retrieve the session management subscription data from the UDM and be notified when the subscription data is modified.

[0243] (5) Step 5: SMF sends a create SM context response message (e.g., Nsmf_PDUSession_CreateSMContext Response) or an update SM context response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to AMF according to the request received in step 3.

[0244] If SMF receives the Nsmf_PDUSession_CreateSMContext Request in step 3 and can process the PDU session establishment request, SMF creates an SM context and responds to AMF by providing the SM context ID.

[0245] If the SMF decides not to accept the PDU session establishment, the SMF rejects the UE request by sending a NAS SM signal including the relevant SM rejection cause by responding to the AMF with an Nsmf_PDUSession_CreateSMContext Response. The SMF also indicates to the AMF that the PDU session ID is considered released and the SMF proceeds to step 20 below, aborting the PDU session establishment procedure.

[0246] (6) Step 6: Optional secondary authentication / authorization may be performed.

[0247] (7a) Step 7a: When dynamic policy and charging control (PCC) is used in a PDU session, the SMF can perform PCF selection.

[0248] (7b) Step 7b: SMF performs the SM policy association establishment procedure to establish a PCF and SM policy association, and obtains the basic PCC rules for the PDU session.

[0249] (8) Step 8: SMF selects one or more UPFs.

[0250] (9) Step 9: The SMF may provide information about the satisfied policy control request trigger conditions by performing the SM policy association modification procedure initiated by the SMF.

[0251] (10) Step 10: If the request type indicates an "Initial Request," the SMF may initiate the N4 Session Establishment procedure with the selected UPF. Otherwise, the SMF may initiate the N4 Session Modification procedure with the selected UPF.

[0252] In step 10a, the SMF can send an N4 session establishment / modification request to the UPF, providing packet detection, enforcement, and reporting rules to be installed in the UPF for the PDU session. In step 10b, the UPF can confirm by sending an N4 session establishment / modification response.

[0253] (11) Step 11: SMF sends an N1N2 message transfer message (e.g. Namf_Communication_N1N2 Message Transfer) to AMF.

[0254] The N1N2 Message Forwarding message may contain N2 SM information. The N2 SM information carries the following information that the AMF will forward to the (R)AN:

[0255] - CN Tunnel Info: Corresponds to the core network address of the N3 tunnel corresponding to the PDU session;

[0256] - QFI (QoS flow ID) corresponding to one or more QoS (quality of service) profiles;

[0257] - PDU Session ID: Indicates to the UE the association between RAN resources and a PDU session for the UE;

[0258] - S-NSSAI with value for serving PLMN (i.e. HPLMN S-NSSAI, or VPLMN S-NSSAI in case of LBO roaming);

[0259] - User plane security enforcement information determined by SMF;

[0260] - UE integrity protection maximum data rate received in PDU session establishment request message: if integrity protection is indicated as "Preferred" or "Required" in the user plane security enforcement information.

[0261] - RSN (redundancy sequence number) parameter

[0262] The N1N2 message transfer message may include an N1 SM container. The N1 SM container includes a PDU Session Establishment Accept message that the AMF will provide to the UE. The PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI. For the LBO roaming scenario, the PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI for the VPLMN, and also includes the corresponding S-NSSAI of the HPLMN from the mapping of the allowed NSSAI received by the SMF in step 3.

[0263] Multiple QoS rules, QoS flow levels, and QoS parameters may be included in the PDU session establishment accept message and N2 SM information within the N1 SM container, if required, for QoS flows associated with QoS rules and QoS profiles.

[0264] If the PDU session establishment fails between steps 5 and 11, the N1N2 message forwarding message contains an N1 SM container containing a PDU session establishment rejection message, but does not contain N2 SM information. The (R)AN sends an NAS message containing a PDU session establishment rejection message to the UE. In this case, steps 12-17 below are omitted.

[0265] (12) Step 12: AMF sends a NAS message containing the PDU Session ID and PDU Session Establishment Accept message destined for the UE and the N2 SM information received from SMF to (R)AN within an N2 PDU Session Request message.

[0266] (13) Step 13: The (R)AN may perform AN-specific signaling exchanges with the UE related to the information received from the SMF. For example, in the case of the NG-RAN, the UE may perform an RRC connection reconfiguration with the UE to set up the necessary NG-RAN resources related to the QoS rules for the PDU session request received in step 12.

[0267] (R)AN forwards the NAS message (PDU Session ID, N1 SM container (PDU Session Establishment Accept message)) received in step 12 to the UE. (R)AN provides the NAS message to the UE only if the AN-specific signaling exchange with the UE includes (R)AN resource additions related to the received N2 command.

[0268] If N2 SM information is not included in step 11, steps 14-16b and 17 below are omitted.

[0269] Now, the procedure of Fig. 9 following the procedure of Fig. 8 is described.

[0270] (14) Step 14: (R)AN sends an N2 PDU Session Response message to AMF. The N2 PDU Session Response message may include PDU Session ID, cause, N2 SM information (PDU Session ID, AN tunnel information, accepted / rejected QFI list, user plane enforcement policy notification), etc.

[0271] (15) Step 15: AMF sends an update SM context request message (e.g., Nsmf_PDUSession_UpdateSMContext Request) to SMF. AMF forwards the N2 SM information received from (R)AN to SMF.

[0272] (16a) Step S16a: SMF initiates the N4 session modification procedure with UPF. SMF provides AN tunnel information and corresponding forwarding rules to UPF.

[0273] (16b) Step S16b: UPF provides an N4 session modification response to SMF.

[0274] After this step, the UPF can forward any DL packets that may have been buffered for this PDU session to the UE.

[0275] (16c) Step 16c: If the SMF is not yet registered for this PDU session, the SMF may register with the UDM for the given PDU session.

[0276] (17) Step 17: SMF sends an update SM context response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to AMF.

[0277] After this step, AMF forwards the relevant events to which SMF subscribes.

[0278] (18) Step 18: At any time during the procedure after Step 5, if the PDU session establishment is not successful, the SMF can notify the AMF by calling Nsmf_PDUSession_SMContextStatusNotify (release). The SMF can also release the created N4 session, the PDU session address (e.g., IP address) if assigned, and possibly the association with the PCF. In this case, Step 19 below is omitted.

[0279] (19) Step 19: For PDU session type IPv6 or IPv4v6, SMF may generate and send an IPv6 Router Advertisement to the UE.

[0280] (20) Step 20: SMF can perform SM policy association modification initiated by SMF.

[0281] (21) Step 21: If the PDU session establishment fails after step 4, the SMF may unsubscribe from modifications to the session management subscription data if the SMF no longer processes the UE's PDU session.

[0282] Network Slice

[0283] Below, we explain network slicing to be introduced in next-generation mobile communications.

[0284] Next-generation mobile communications introduce the concept of network slicing to provide diverse services through a single network. Here, a network slicing refers to a combination of network nodes with the functions necessary to provide a specific service. The network nodes that make up a slice instance can be either hardware-independent or logically independent.

[0285] Each slice instance can be composed of any combination of nodes required to form the entire network. In this case, a single slice instance can provide services to a UE independently.

[0286] Alternatively, a slice instance may be composed of a combination of nodes within the network. In this case, the slice instance may not provide services to the UE independently, but may instead collaborate with other existing network nodes to provide services to the UE. Furthermore, multiple slice instances may collaborate to provide services to the UE.

[0287] Slice instances differ from dedicated core networks in that the entire network, including the core network (CN) nodes and the RAN, can be separated. Furthermore, slice instances differ from dedicated core networks in that network nodes can be logically separated.

[0288] Figure 10 is an example diagram showing an example of an architecture for implementing the concept of network slicing.

[0289] As can be seen from Figure 10, a core network (CN) can be divided into multiple slice instances. Each slice instance can include one or more CP functional nodes and UP functional nodes.

[0290] Each UE can use a network slice instance suitable for its service through the RAN.

[0291] Unlike the one illustrated in Figure 10, each slice instance may share one or more of the CP function nodes and UP function nodes with other slice instances. This is described below with reference to Figure Z-5.

[0292] Figure 11 is an example diagram showing another example of an architecture for implementing the concept of network slicing.

[0293] Referring to FIG. 11, multiple UP function nodes are clustered, and similarly multiple CP function nodes are clustered.

[0294] And, referring to FIG. 11, slice instance #1 (or referred to as instance #1) within the core network includes a first cluster of UP functional nodes. And, the slice instance #1 shares a cluster of CP functional nodes with slice #2 (or referred to as instance #2). The slice instance #2 includes a second cluster of UP functional nodes.

[0295] The illustrated NSSF selects a slice (or instance) that can accommodate the UE's service.

[0296] The illustrated UE can use service #1 through slice instance #1 selected by the NSSF, and can also use service #2 through slice instance #2 selected by the N.

[0297] 1. Network Slice Replacement

[0298] The Network Slice Replacement feature can be used to temporarily replace an S-NSSAI with an alternative S-NSSAI when the S-NSSAI becomes unavailable or congested in 5GC. Network slice replacement can be performed in the following cases:

[0299] - When NSSF detects that an S-NSSAI becomes unavailable or congested (e.g., based on OAM or NWDAF analysis output), NSSF sends a network slice availability notification for the S-NSSAI to AMF. This notification may include an alternate S-NSSAI that AMF can use to replace the S-NSSAI, as well as congestion mitigation information if the S-NSSAI is congested. NSSF notifies AMF when the S-NSSAI becomes available again.

[0300] - When the PCF detects that S-NSSAI is unavailable or congested for the UE (e.g., based on OAM or NWDAF analysis output), the PCF sends an access and mobility-related policy notification to the AMF. The notification may include an alternate S-NSSAI that the AMF can use to replace the S-NSSAI. The PCF notifies the AMF when the S-NSSAI becomes available again for the UE.

[0301] - OAM notifies AMF when an S-NSSAI becomes unavailable or congested (and when it becomes available again), provides an alternative S-NSSAI to AMF, and OAM can provide congestion mitigation information when an S-NSSAI is congested.

[0302] Based on the above notifications from NSSF, PCF, or OAM, the AMF may decide to replace the S-NSSAI with an alternate S-NSSAI. In roaming, the AMF may subscribe to network slice availability notifications from the HPLMN S-NSSAI from the VPLMN's NSSF, and the VPLMN's NSSF may subscribe to notifications from the HPLMN's NSSF.

[0303] AMF can use the alternate S-NSSAI received in the notification from NSSF, OAM, or PCF. If NSSF, PCF, or OAM do not provide an alternate S-NSSAI in the notification, AMF can use an alternate S-NSSAI based on its local configuration. The alternate S-NSSAI must be supported in the UE registration area. If AMF cannot determine an alternate S-NSSAI for the S-NSSAI (e.g., OAM or NSSF does not provide an alternate S-NSSAI and there is no alternate S-NSSAI in AMF local configuration), AMF can additionally interact with PCF to determine an alternate S-NSSAI.

[0304] If an alternate S-NSSAI is subject to NSSAA, the alternate S-NSSAI is only used by UEs whose subscribed S-NSSAI includes the alternate S-NSSAI. In this case, the AMF may perform the NSSAA procedure for the alternate S-NSSAI before triggering a network slice replacement, as specified below.

[0305] A UE may indicate support for the network slice replacement feature during the UE registration procedure. If a UE supports CM-CONNECTED state and there is a PDU session in the UE context associated with an S-NSSAI that needs to be replaced via an access type, the AMF may additionally provide a replacement S-NSSAI for this S-NSSAI in addition to the allowed NSSAIs and configured NSSAIs (if not already included) via the same access type, and may provide the UE with a mapping between the S-NSSAI and the replacement S-NSSAI in the UE Configuration Update message as follows:

[0306] - For non-roaming UEs, AMF may provide the UE with a mapping between S-NSSAI and alternative S-NSSAI.

[0307] - For roaming UEs, if the VPLMN S-NSSAI needs to be replaced with a VPLMN alternative S-NSSAI, the AMF may map the VPLMN S-NSSAI to the alternative VPLMN S-NSSAI and provide it to the UE.

[0308] - For a roaming UE, if the HPLMN S-NSSAI needs to be replaced with an alternative HPLMN S-NSSAI, the AMF can map the HPLMN S-NSSAI to the alternative HPLMN S-NSSAI and provide it to the UE.

[0309] For roaming, the alternate HPLMN S-NSSAI is always part of the subscription S-NSSAI, so the alternate HPLMN S-NSSAI does not need to be one of the subscription S-NSSAIs.

[0310] AMF can map an S-NSSAI to an alternate S-NSSAI via an access that triggers a network slice replacement. The UE stores the received mapping information along with the received access type and can use it only via that access.

[0311] Since network slice replacement is applied independently of access type, when a replacement occurs, the same replacement S-NSSAI mapping for the replaced S-NSSAI can be provided via the access type in the allowed NSSAI.

[0312] If the replaced S-NSSAI cannot be maintained in the Allowed NSSAI or Partially Allowed NSSAI, the AMF may additionally remove the replacement S-NSSAI from the Allowed NSSAI or Partially Allowed NSSAI if the replacement S-NSSAI is used only for network slice replacement.

[0313] When moving between AMFs, the source AMF may provide the new AMF with an alternate S-NSSAI and an alternate S-NSSAI mapping for the alternate S-NSSAI in the UE context. If the S-NSSAI is subject to network slice replacement, the new AMF may update any UEs that are missing the alternate S-NSSAI and the alternate S-NSSAI mapping by comparing the requested NSSAI with the received UE context.

[0314] For supporting UEs, if the UE has a NAS signaling connection, i.e. is in CM-CONNECTED state or has become CM-CONNECTED state (e.g. through a service request procedure or a UE registration procedure), and if the AMF determines that the S-NSSAI needs to be replaced and there is a PDU session associated with the S-NSSAI in the UE context, the AMF may send the UE a UE configuration update message or a registration accept message mapping the S-NSSAI to the replacement S-NSSAI.

[0315] If there is no PDU session associated with the S-NSSAI, the AMF local policy determines whether to send the mapping of the S-NSSAI to an alternate S-NSSAI to the UE, or to wait until the UE establishes a PDU session associated with the S-NSSAI and then send the mapping of the S-NSSAI to the alternate S-NSSAI to the UE.

[0316] When an S-NSSAI is replaced with a replacement S-NSSAI, the UE can associate both the replaced S-NSSAI and the replacement S-NSSAI with a PDU session. The UE procedures for associating an application to a PDU session and establishing a PDU session based on URSP are based on the replaced S-NSSAI (not the replacement S-NSSAI).

[0317] During the new PDU session setup procedure for S-NSSAI,

[0318] - If the UE receives information mapping the S-NSSAI to a replacement S-NSSAI together with the allowed NSSAI, the UE can include both the replacement S-NSSAI and the S-NSSAI in the PDU Session Setup message. When the AMF receives the replacement S-NSSAI and the S-NSSAI in the PDU Session Setup message, the AMF uses the SMF selection subscription data of the replaced S-NSSAI to select an appropriate SMF that supports network slice replacement and the replacement S-NSSAI, verifies the replacement S-NSSAI and the S-NSSAI based on the UE context, and then includes both the replacement S-NSSAI and the S-NSSAI in the SMF in the Nsmf_PDUSession_CreateSMContext service operation.

[0319] - If the UE has not yet received a mapping between the S-NSSAI and the alternate S-NSSAI via the allowed NSSAI, the UE may provide only the S-NSSAI in the PDU Session Setup message. If the AMF determines that the requested S-NSSAI should be replaced with the alternate S-NSSAI and the UE supports network slice replacement, the AMF may reconfigure the UE with the alternate S-NSSAI by performing a UE configuration update procedure. The AMF may continue the PDU Session Setup procedure using the alternate S-NSSAI and select an appropriate SMF that supports both network slice replacement and the alternate S-NSSAI using the SMF selection subscription data of the replaced S-NSSAI. The AMF may provide both the alternate S-NSSAI and the S-NSSAI to the SMF via the Nsmf_PDUSession_CreateSMContext service operation.

[0320] The SMF can use the alternate S-NSSAI and the received DNN to establish a PDU session. The SMF can retrieve subscription data using the alternate S-NSSAI and DNN. The SMF can use the alternate S-NSSAI value when registering a PDU session in the UDM. The SMF can transmit the alternate S-NSSAI to the NG-RAN via the N2 SM information and to the UE via the PDU Session Setup Accept message.

[0321] For an existing PDU session associated with an S-NSSAI that has been replaced with a replacement S-NSSAI, after the AMF sends the mapping of the S-NSSAI to the replacement S-NSSAI in the UE Configuration Update message to the supporting UE, the AMF may send an update to the SMF for the PDU session indicating that the PDU session should be transported with the replacement S-NSSAI and that the replacement S-NSSAI includes:

[0322] - If the SMF determines that the PDU session should be maintained (e.g., if the anchor UPF can be reused with an alternate S-NSSAI and SSC Mode 1), the SMF may send the alternate S-NSSAI to the UPF in an N4 message, to the NG-RAN in an N2 message, and to the supporting UE in a PDU Session Modification Command message. The S-NSSAI provided to the (R)AN and the UPF may be the alternate S-NSSAI.

[0323] - If the SMF determines that a PDU session reset is required, the SMF can trigger the PDU session reset by sending an alternate S-NSSAI to the supporting UE via a PDU Session Modification Command if the PDU session is in SSC mode 3, or via a PDU Session Release if the PDU session is in SSC mode 2 or SSC mode 1. The UE can include both the S-NSSAI and the alternate S-NSSAI in the PDU Session Setup message.

[0324] During the registration process, the requested NSSAI may contain an alternate S-NSSAI other than the subscribed S-NSSAI. The AMF can verify whether the S-NSSAI in the requested NSSAI is a subscribed S-NSSAI or an alternate S-NSSAI in the UE context, and decide whether to update the UE configuration based on this verification.

[0325] When the AMF is notified that an S-NSSAI is available again (e.g., congestion on the S-NSSAI has eased), if the AMF has configured the serving UE with an alternate S-NSSAI and the AMF decides that the UE in CM-CONNECTED state should use the replaced S-NSSAI again, the AMF may reconfigure the serving UE (e.g., using the UE configuration update procedure or through the following registration procedure), remove the alternate S-NSSAI mapping of the replaced S-NSSAI, and remove the replaced S-NSSAI from the allowed NSSAIs if the replaced S-NSSAI is used only for network slice replacement. The AMF may remove the replaced S-NSSAI from the configured NSSAIs if it is not one of the subscribed S-NSSAIs and is not used for any access type. If the UE is in CM-IDLE state, the AMF may wait until the UE is in CM-CONNECTED state. When a UE establishes a NAS signaling connection through a service request procedure or a UE registration procedure, the AMF can reconfigure the UE.

[0326] If there is an existing PDU session associated with a replacement S-NSSAI for an S-NSSAI, and that S-NSSAI is available again or no longer congested, AMF updates the SMF for that PDU session via the Nsmf_PDUSession_UpdateSMContext service operation so that the PDU session is transferred to the replacement S-NSSAI.

[0327] - If the SMF determines that the PDU session should be maintained (e.g., if the anchor UPF can be reused with the replaced S-NSSAI and SSC Mode 1), the SMF may transmit the replaced S-NSSAI. That is, the N4 message does not include the replacement S-NSSAI for the UPF, the N2 message to the NG-RAN, and the PDU Session Modification Command message does not include the replacement S-NSSAI for the supporting UE. The S-NSSAI provided to the (R)AN and the UPF is the replaced S-NSSAI.

[0328] - If the SMF determines that the PDU session needs to be re-established, the SMF may trigger the PDU session re-establishment by sending an alternate S-NSSAI (i.e., not including the alternate S-NSSAI) to the supporting UE via a PDU Session Modification command (if the PDU session is in SSC mode 3) or a PDU Session Release (if the PDU session is in SSC mode 2 or SSC mode 1). The UE may include the alternate S-NSSAI in the PDU Session Setup message.

[0329] If the S-NSSAI needs to be replaced with a replacement S-NSSAI during a handover procedure, the handover procedure (including all PDU sessions associated with the S-NSSAI to be replaced) may continue unaffected by the network slice replacement. Network slice replacement for the S-NSSAI may not be performed during the handover.

[0330] If the S-NSSAI needs to be replaced with a replacement S-NSSAI during the NSSAA recertification procedure for the S-NSSAI, the AMF may continue the NSSAA procedure without being affected by the network slice replacement, and may execute the network slice replacement after the NSSAA procedure is completed.

[0331] If NSAC for the maximum number of PDU sessions is configured for the replaced S-NSSAI and / or the alternate S-NSSAI, the SMF may interact with the NSACF of the replaced S-NSSAI and / or the NSACF of the alternate S-NSSAI to execute NSAC according to the operator decision policies configured in the SMF (e.g., increased replaced S-NSSAI and decreased replaced S-NSSAI).

[0332] 2. Controlling the use of network slices based on mobility management

[0333] If the network supports network slice usage control, the AMF can monitor network slice usage by running a slice deregistration inactivity timer per S-NSSAI and access type. If the UE supports network slice usage control, the AMF can also provide an on-demand NSSAI to the UE via a registration accept message or a configuration update command message. An on-demand NSSAI can consist of one or more on-demand S-NSSAIs and, optionally, a slice deregistration inactivity timer per on-demand S-NSSAI.

[0334] The slice deregistration inactivity timer can be started using the saved slice deregistration inactivity timer value as follows:

[0335] a) For PDU sessions released using 5GSM signaling, if the PDU session is released and there are no established PDU sessions, including MA PDU sessions associated with S-NSSAI via that access type.

[0336] b) For locally released PDU sessions: 1) When the UE or AMF receives a PDU Session Status IE indicating that the PDU Session is currently in 5GSM state and there are no established PDU sessions, including MA PDU sessions, associated with S-NSSAI via that Access Type; or 2) When the UE or AMF receives a PDU Session Status IE indicating that the PDU Session was previously in 5GSM state and there are no established PDU sessions, including MA PDU sessions, associated with S-NSSAI via that Access Type.

[0337] The slice deregistration inactivity timer may be stopped and reset when a PDU session (including a MA PDU session) associated with the S-NSSAI is successfully established via that access type or when the S-NSSAI is removed from the allowed NSSAIs.

[0338] c) When the UE enters 5GMM-DEREGISTERED state, it may be stopped and reset.

[0339] When the slice deregistration inactivity timer value is updated, the AMF may update the stored timer value and provide the updated timer value to the UE via a registration accept message, a current or next registration procedure for mobility and periodic registration update, or a configuration update command message.

[0340] When the UE receives an updated slice deregistration inactivity timer value via a registration accept message or a configuration update command message from AMF, the UE may update the stored timer value.

[0341] When the slice deregistration inactivity timer expires, AMF can:

[0342] a) For UEs that support network slice usage control, the S-NSSAI can be locally removed from the allowed NSSAIs through the corresponding access type. In addition, the AMF can send a configuration update command message to the UE with the new allowed NSSAI. And

[0343] b) For UEs that do not support network slice usage control, the updated allowed NSSAI, excluding S-NSSAI, can be provided to the UE in a CONFIGURATION UPDATE COMMAND message.

[0344] The UE may include the on-demand S-NSSAI requested by the UE in the NSSAI requested during the registration procedure. When the slice deregistration inactivity timer expires, the UE may locally remove the S-NSSAI from the allowed NSSAIs for the corresponding access type.

[0345] If the UE determines on-demand S-NSSAI for PDU session establishment, the UE may include the on-demand S-NSSAI in the NSSAI requested during the registration procedure.

[0346] An on-demand NSSAI may be associated with a configured NSSAI. If the UE deletes the associated configured S-NSSAI from the stored NSSAI, the on-demand S-NSSAI may be deleted from the stored NSSAI.

[0347] 3. Session management-based network slice replacement

[0348] In the following cases:

[0349] a) If the UE and the network support network slice replacement;

[0350] b) When mapping information between the S-NSSAI to be replaced and the replacement S-NSSAI is provided to the UE;

[0351] c) If the UE decides to establish a new PDU session with the S-NSSAI to be replaced,

[0352] The UE may provide both the S-NSSAI to be replaced and the alternative S-NSSAI during the PDU session establishment procedure. If timer T3584 or T3585 is running for the S-NSSAI to be replaced, the UE shall not stop the timer during the PDU session establishment procedure. If the SMF receives both the S-NSSAI to be replaced and the alternative S-NSSAI during the PDU session establishment procedure, the SMF may proceed with the PDU session establishment procedure using the alternative S-NSSAI. If the PDU session establishment request is accepted, the SMF may include the alternative S-NSSAI in the PDU session establishment accept message. The S-NSSAIs for the established PDU session are the replaced S-NSSAI and the alternative S-NSSAI on the UE side.

[0353] If the UE is provided with mapping information between the VPLMN S-NSSAI and the VPLMN fallback S-NSSAI, the UE can provide both the VPLMN fallback S-NSSAI and the VPLMN S-NSSAI during the PDU session setup procedure. The AMF can send both the VPLMN fallback S-NSSAI and the VPLMN S-NSSAI to the SMF. If the UE is provided with mapping information between the HPLMN S-NSSAI and the HPLMN fallback S-NSSAI, the UE can provide both the HPLMN fallback S-NSSAI and the HPLMN S-NSSAI during the PDU session setup procedure. The AMF can send both the HPLMN fallback S-NSSAI and the HPLMN S-NSSAI to the SMF.

[0354] SMF receives a replacement S-NSSAI for an existing PDU session from AMF:

[0355] a) If the SMF decides to maintain the existing PDU session (i.e., if the SMF can provide both an alternate S-NSSAI and an alternate S-NSSAI), the SMF may send the alternate S-NSSAI to the UE during the network request PDU session modification procedure. or

[0356] b) If the SMF decides to reactivate an existing PDU session and: 1) the SSC mode of the PDU session is SSC mode 3, the SMF initiates a PDU session modification procedure to trigger reactivation of the UE's PDU session; or 2) the SSC mode of the PDU session is SSC mode 1 or SSC mode 2, the SMF initiates a PDU session release procedure to trigger reactivation of the UE's PDU session, and the UE provides both the alternate S-NSSAI and the fallback S-NSSAI during the PDU session setup procedure.

[0357] When the replaced S-NSSAI becomes available again, the SMF receives the replaced S-NSSAI for the existing PDU session from the AMF and:

[0358] a) If the SMF decides to maintain the existing PDU session (i.e., if the SMF can provide a replaced S-NSSAI), the SMF sends the replaced S-NSSAI to the UE during the network request PDU session modification procedure; or

[0359] b) When the SMF decides to reactivate an existing PDU session: 1) if the SSC mode of the PDU session is SSC mode 3, the SMF sends the replaced S-NSSAI to the UE during the PDU session modification procedure, triggering the UE to reactivate the PDU session; or 2) if the SSC mode of the PDU session is SSC mode 1 or SSC mode 2, the SMF sends the replaced S-NSSAI to the UE during the PDU session release procedure, triggering the UE to reactivate the PDU session; or the UE provides the replaced S-NSSAI during the PDU setup procedure.

[0360] If Timer T3584 or Timer T3585 is running for the replaced S-NSSAI and the replaced S-NSSAI is available for the replacement NSSAI and the AMF provides the UE with the updated allowed NSSAI and the configured NSSAI, the UE may stop the timer.

[0361] 4. Controlling and replacing network slice usage

[0362] Release 18 introduced new network slicing features called network slice usage control and network slice replacement. The purpose of network slice control is to ensure that connected applications register with a network slice only when they require data transmission on that network slice. The purpose of network slice replacement is to temporarily replace the S-NSSAI of an allowed NSSAI with another S-NSSAI.

[0363] To control network slice usage, the network may determine one or more S-NSSAIs from the configured NSSAIs as on-demand S-NSSAIs and optionally define a slice deregistration inactivity timer value per on-demand S-NSSAI. The slice deregistration inactivity timer associated with this list of on-demand S-NSSAIs may be configured in the UE via a Registration Accept message or a Configuration Update Command message. The UE may transmit the on-demand S-NSSAI as a requested NSSAI included in a Registration Request message for slice registration only when the UE intends to request the network to establish an associated PDU session when the associated application requires data transmission in the network slice.

[0364] When UPF notifies SMF of a PDU session inactivity event, the PDU session may be released because UPF does not detect ongoing data packet transmission until the PDU session inactivity timer expires.

[0365] When the last PDU session associated with the on-demand S-NSSAI is released, the UE and AMF may start a slice deregistration inactivity timer. Upon expiration of the slice deregistration inactivity timer, the UE and AMF may locally remove the on-demand S-NSSAI from the allowed NNSI.

[0366] The AMF may send a Configuration Update Command message to the UE to update the allowed NSSAIs, excluding the on-demand S-NSSAI. When the first associated PDU session is established or the on-demand S-NSSAI is removed from the allowed NSSAIs, the UE and the AMF may stop the slice deregistration inactivity timer.

[0367] In case of network slice replacement due to temporary unavailability or network congestion, AMF may send slice replacement mapping information consisting of the S-NSSAI to be replaced and the replacement S-NSSAI to the UE. If the replaced S-NSSAI cannot be maintained, AMF may (partially) remove the S-NSSAI from the allowed NSSAIs.

[0368] If the AMF determines that the replaced S-NSSAI can be reused, the AMF may provide the UE with an updated replacement NSSAI, excluding the replaced S-NSSAI and its replacement S-NSSAI, during the UE configuration update procedure or registration procedure.

[0369] The alternate NSSAI and the S-NSSAI mapped to the alternate NSSAI (if the UE is roaming) may be stored until a new alternate NSSAI for the same access type (i.e., 3GPP access or non-3GPP access) for the given PLMN and equivalent PLMN or SNPN is received for the given PLMN or SNPN.

[0370] When a new alternate NSSAI is received for a given PLMN or SNPN and contains a list of mapping information between the S-NSSAI to be replaced by the new alternate NSSAI and the alternate S-NSSAI, the UE may:

[0371] 1) Any alternate NSSAI stored for this PLMN and equivalent PLMN or this SNPN for the same access type may be replaced with a new alternate NSSAI for this PLMN or SNPN. And

[0372] 2) Delete the stored mapped S-NSSAI for this PLMN and its equivalent PLMN or alternate NSSAI for this SNPN for the same access type, and store the mapped S-NSSAI for the new alternate NSSAI, if available.

[0373] If a new alternate NSSAI is received for a particular PLMN or SNPN and the alternate NSSAI does not contain any mapping information between the S-NSSAI to be replaced and the alternate S-NSSAI, the UE may delete all alternate NSSAIs stored for this PLMN and its equivalent PLMNs or this SNPN for the same access type.

[0374] As shown in FIGS. 12 to 15, slice usage control information and slice replacement information can be transmitted to the UE through a registration acceptance message or a configuration update command message.

[0375] For example, a message (e.g., a registration acceptance message, a configuration update command message) may include the information of FIGS. 12 to 15.

[0376] Figure 12 illustrates an example of an alternative NSSAI information element.

[0377] Registration Accept messages, configuration update command messages, PDU session modify commands, and PDU session teardown commands may include an alternate NSSAI.

[0378] Alternative NSSAI information elements may contain entries.

[0379] Figure 13 shows an example of an entry.

[0380] In this specification, an entry included in a replacement NSSAI may include information about the replaced S-NSSAI and the replacement S-NSSAI.

[0381] In this specification, an entry included in a replacement NSSAI may be mapping information between a replaced S-NSSAI and a replacement S-NSSAI.

[0382] In this specification, the mapping information between the replaced S-NSSAI and the alternative S-NSSAI may mean an entry including the replaced S-NSSAI and the alternative S-NSSAI stored in the alternative NSSAI.

[0383] For example, a replacement NSSAI may contain entries containing a replaced S-NSSAI and a replacement S-NSSAI.

[0384] The UE and AMF can each store alternative NSSAIs.

[0385] Figure 14 illustrates an example of an on-demand NSSAI information element.

[0386] Figure 15 shows an example of on-demand S-NSSAI information.

[0387] Previously, when an on-demand S-NSSAI is replaced with another on-demand S-NSSAI, the UE and network behavior (e.g., how to handle when a slice deregistration inactivity timer is running, how to handle mapping information between the replaced S-NSSAI and the replacement S-NSSAI, etc.) was not discussed.

[0388] This specification may propose UE and network behavior when AMF sets up slice replacement and the replacement S-NSSAI or the replaced S-NSSAI is an on-demand S-NSSAI (when both the replacement S-NSSAI and the replaced S-NSSAI are on-demand S-NSSAI).

[0389] To enable the serving network to guide the UE to its preferred network slice, the AMF may request the UE to transfer a PDU session from one S-NSSAI to another S-NSSAI based on the network slice replacement capability.

[0390] Figure 16 shows an example where slice replacement occurs for on-demand S-NSSAI.

[0391] The replaced S-NSSAI may be an on-demand S-NSSAI.

[0392] S-NSSAI#1 may be an on-demand S-NSSAI.

[0393] 1)

[0394] After a particular network slice (e.g., S-NSSAI#1) is included in the allowed NSSAIs and before it is removed from the allowed NSSAIs, the network may replace the particular network slice (replaced S-NSSAI) with another network slice (alternative S-NSSAI) due to network congestion (or other reasons).

[0395] 2)

[0396] After the associated PDU Session is established for a particular network slice (replaced S-NSSAI), the UE / AMF does not start the slice deregistration inactivity timer for that network slice until all associated PDU Sessions are released.

[0397] However, if the network slice (replaced S-NSSAI) is replaced, it is unclear whether the slice deregistration inactivity timer for the slice mapped to the original network slice (replaced S-NSSAI) should be started.

[0398] Additionally, if the alternative S-NSSAI is an on-demand S-NSSAI, it is unclear how to handle the slice deregistration inactivity timer for the slice for the alternative S-NSSAI.

[0399] For example, it is unclear whether the slice deregistration inactivity timer for a slice for an alternate S-NSSAI should be stopped if the slice deregistration inactivity timer for the slice is already running.

[0400] 3)

[0401] After all PDU sessions are released, if the replaced S-NSSAI or alternative S-NSSAI (or both the replaced S-NSSAI and the alternative S-NSSAI) remain on an allowed NSSAI, it is unclear for which network slice the timer (slice deregistration inactivity timer) will be started if the replaced S-NSSAI and / or alternative S-NSSAI is an on-demand S-NSSAI.

[0402] When a slice replacement is performed, if the replaced S-NSSAI or the replacement S-NSSAI (or both the replaced S-NSSAI and the replacement S-NSSAI) is an on-demand S-NSSAI, the question arises as to how to manage the timer (slice deregistration inactivity timer) matched to the on-demand S-NSSAI.

[0403] When the timer is running, the question arises as to how the allowed NSSAI and mapping information (the mapping information between the replaced S-NSSAI and the replacement S-NSSAI) will be managed.

[0404] In this regard, the method proposed in this specification is described below.

[0405] The method proposed in this specification may be composed of a combination of one or more operations / configurations / steps of the methods described below.

[0406] The timer in this specification may mean a slice deregistration inactivity timer.

[0407] In this specification, slice replacement may mean switching (e.g., switching network resource allocation) from a replaced S-NSSAI to an alternative S-NSSAI. The slice replacement may be performed because the replaced S-NSSAI becomes unavailable.

[0408] In this specification, a timer may be started when all PDU sessions associated with a network slice corresponding to on-demand are released.

[0409] Depending on whether the replaced S-NSSAI or the alternative S-NSSAI is the on-demand S-NSSAI, the actions performed by the UE / AMF may differ.

[0410] 1) If both the replaced S-NSSAI and the replacement S-NSSAI are not on-demand S-NSSAI.

[0411] Conventional legacy network slice replacement operations can be performed.

[0412] 2) If the replaced S-NSSAI is an on-demand S-NSSAI and the replacement S-NSSAI is not an on-demand S-NSSAI.

[0413] The UE and AMF may start / run a timer (slice deregistration inactivity timer) for the replaced S-NSSAI.

[0414] When the timer expires, the UE and AMF may delete the replaced S-NSSAI from the allowed NSSAI. Alternatively, the UE and AMF may delete both the replaced S-NSSAI and the replacement S-NSSAI from the allowed NSSAI. In addition, the UE and AMF may delete the mapping information (the mapping information between the replaced S-NSSAI and the replacement S-NSSAI).

[0415] 3) If the replaced S-NSSAI is not an on-demand S-NSSAI and the replacement S-NSSAI is an on-demand S-NSSAI.

[0416] The UE and AMF may drive / start a timer (slice deregistration inactivity timer) for the replaced S-NSSAI.

[0417] When the timer expires, the UE and AMF may delete the replacement S-NSSAI from the allowed NSSAI. Alternatively, the UE and AMF may delete both the replaced S-NSSAI and the replacement S-NSSAI from the allowed NSSAI. In addition, the UE and AMF may delete the mapping information (the mapping information between the replaced S-NSSAI and the replacement S-NSSAI).

[0418] 4) If both the replaced S-NSSAI and the replacement S-NSSAI are on-demand S-NSSAI.

[0419] 4-1)

[0420] The UE and AMF may drive / start a timer (slice deregistration inactivity timer) for each of the replaced S-NSSAI and the alternative S-NSSAI.

[0421] When either of the timers expires, the UE and AMF may delete both the replaced S-NSSAI and the alternate S-NSSAI from the allowed NSSAI. In addition, the UE and AMF may delete the mapping information (the mapping information between the replaced S-NSSAI and the alternate S-NSSAI).

[0422] 4-2)

[0423] The UE and AMF may drive / start a timer (slice deregistration inactivity timer) for either the replaced S-NSSAI or the alternate S-NSSAI.

[0424] When the timer expires, the UE and AMF may delete both the replaced S-NSSAI and the alternative S-NSSAI from the allowed NSSAI. In addition, the UE and AMF may delete the mapping information (the mapping information between the replaced S-NSSAI and the alternative S-NSSAI).

[0425] In this specification, if a PDU session using a replaced S-NSSAI is replaced with an alternative S-NSSAI, the PDU session may be considered to use both the replaced S-NSSAI and the alternative S-NSSAI resources. For example, if a PDU session using slice #1 is replaced with slice #2, the PDU session may be considered to be using both slice #1 and slice #2.

[0426] In this specification, the occurrence of a slice replacement can be interpreted as the network slice mapping for a PDU session using the replaced S-NSSAI being changed to an alternative S-NSSAI. Furthermore, even if no slice replacement is performed for the actual session, it can be interpreted that the AMF has provided the UE with the replaced S-NSSAI and the alternative S-NSSAI mapping information.

[0427] This specification can propose a method for managing mapping information between a replaced S-NSSAI and an alternative S-NSSAI and a network slice management method (e.g., Allowed NSSAI management) in the case where on-demand S-NSSAI and slice replacement are decided.

[0428] The method proposed in this specification can be extended and used in various scenarios considering the following cases:

[0429] - Whether to perform the timer (Slice deregistration inactivity timer)

[0430] - Whether NSSAI updates are allowed

[0431] This specification primarily describes the proposed content. For basic slice mapping and slice usage control-related operations and procedures, please refer to TS 24.501 v18.7.0.

[0432] I. Whether to perform a slice release inactivity timer

[0433] The UE (or AMF) may start a deregistration timer for the S-NSSAI corresponding to the on-demand S-NSSAI (replaced S-NSSAI or alternative S-NSSAI).

[0434] The UE (or AMF) may start a slice deregistration timer for a replaced Single-Network Slice Selection Assistance Information (S-NSSAI) or an alternative S-NSSAI.

[0435] 1. If the replaced S-NSSAI is an on-demand S-NSSAI and the replacement S-NSSAI is not an on-demand S-NSSAI.

[0436] When the last relevant PDU session for the replaced S-NSSAI is released (e.g., all sessions using the replaced S-NSSAI are released), and there are no PDU sessions using the replaced S-NSSAI, the UE / AMF may start a slice deregistration inactivity timer for the replaced S-NSSAI.

[0437] In the following cases, the UE / AMF may stop and reset the slice deregistration inactivity timer for the running alternate S-NSSAI.

[0438] - When an associated PDU Session for an alternate S-NSSAI is requested for the first time, or

[0439] - When the replaced S-NSSAI becomes available again and the related PDU session is requested to be established for the first time.

[0440] When the slice deregistration inactivity timer for the replaced S-NSSAI expires, the UE / AMF may delete the replaced S-NSSAI from the allowed NSSAIs. At this time, the UE / AMF may delete any stored mapping information (mapping information between the replaced S-NSSAI and the replacement S-NSSAI) (e.g., entries containing the replaced S-NSSAI or the replacement S-NSSAI).

[0441] When the slice deregistration inactivity timer for the replaced S-NSSAI expires, the UE / AMF may delete the replaced S-NSSAI from the allowed NSSAIs.

[0442] 2. If the replaced S-NSSAI is not an on-demand S-NSSAI and the replacement S-NSSAI is an on-demand S-NSSAI.

[0443] When the last associated PDU Session for the alternate S-NSSAI is released (e.g., all sessions that the replaced S-NSSAI replaced with are released), and there are no PDU Sessions using the alternate S-NSSAI, the UE / AMF may start a slice deregistration inactivity timer for the alternate S-NSSAI.

[0444] Alternatively, if the replaced S-NSSAI becomes unavailable and the associated PDU Session is replaced with a replacement S-NSSAI, or if the associated PDU Session for the replacement S-NSSAI is requested to be established for the first time, the UE / AMF may stop and reset the slice deregistration inactivity timer for the running replacement S-NSSAI.

[0445] When the slice deregistration inactivity timer for the replacement S-NSSAI expires, the UE / AMF may delete the replacement S-NSSAI from the allowed NSSAIs. At this time, the UE / AMF may delete any stored mapping information between the replaced S-NSSAI and the replacement S-NSSAI (e.g., an entry containing the replaced S-NSSAI or the replacement S-NSSAI).

[0446] When the slice deregistration inactivity timer for the replacement S-NSSAI expires, the UE / AMF may delete the replaced S-NSSAI from the allowed NSSAIs.

[0447] 3. If both the replaced S-NSSAI and the replacement S-NSSAI are on-demand S-NSSAI.

[0448] If a slice replacement is performed, and the UE / AMF is running a slice deregistration inactivity timer for the replaced S-NSSAI (but not for the replacement S-NSSAI), and there are no PDU sessions using the replaced S-NSSAI and the replacement S-NSSAI:

[0449] - The UE / AMF can start the timer (slice deregistration inactivity timer) for the replaced S-NSSAI by setting the remaining time of the running timer (slice deregistration inactivity timer) for the replaced S-NSSAI to the replacement S-NSSAI. At this time, the UE / AMF can stop the running timer (slice deregistration inactivity timer) for the replaced S-NSSAI.

[0450] - As another option, the UE / AMF may keep the running timer (slice deregistration inactivity timer) for the replaced S-NSSAI without stopping it. When the timer (slice deregistration inactivity timer) for the replaced S-NSSAI expires, the UE / AMF may delete the replaced S-NSSAI from the allowed NSSAIs. This option may be an option to operate the timers for the replacement S-NSSAI and the replaced S-NSSAI independently.

[0451] - As another option, the UE / AMF can start the timer for the replacement S-NSSAI (slice deregistration inactivity timer) by setting it to the value of the timer received from the network (slice deregistration inactivity timer). At this time, the UE / AMF can stop the running timer for the replaced S-NSSAI (slice deregistration inactivity timer).

[0452] - As another option, the UE / AMF can keep a running timer (slice deregistration inactivity timer) for the replaced S-NSSAI. When the timer for the replaced S-NSSAI expires, the UE / AMF can remove the replaced S-NSSAI from the allowed NSSAIs. This option can be an option to run the timers for the replacement S-NSSAI (slice deregistration inactivity timer) and the replaced S-NSSAI (slice deregistration inactivity timer) independently.

[0453] - When the running time for the replaced S-NSSAI expires, the UE / AMF can delete the replaced S-NSSAI from the allowed NSSAI. At this time, the UE / AMF can delete any stored mapping information between the replaced S-NSSAI and the replacement S-NSSAI (e.g., an entry containing the replaced S-NSSAI or the replacement S-NSSAI). At this time, the UE / AMF can also delete the replaced S-NSSAI from the allowed NSSAI. If there was a running timer (slice deregistration inactivity timer) for the replaced S-NSSAI, the UE / AMF can stop the timer and delete the replaced S-NSSAI from the allowed NSSAI.

[0454] - When a running timer (slice deregistration inactivity timer) for the replaced S-NSSAI expires, the UE / AMF can delete the replaced S-NSSAI from the allowed NSSAIs. At this time, the UE / AMF can delete any stored mapping information between the replaced S-NSSAI and the replaced S-NSSAI (e.g., an entry containing the replaced S-NSSAI or the replaced S-NSSAI). At this time, the UE / AMF can also delete the replaced S-NSSAI from the allowed NSSAIs. If there was a running timer (slice deregistration inactivity timer) for the replaced S-NSSAI, the UE / AMF can stop the timer and delete the replaced S-NSSAI from the allowed NSSAIs.

[0455] II. Whether NSSAI updates are permitted

[0456] Here, it can be considered that the UE has received an allowed NSSAI from the network.

[0457] Here, the case where the UE deletes the S-NSSAI mapped to the timer itself from the allowed NSSAI (locally remove) due to expiration of the timer (slice deregistration inactivity timer) may not be considered.

[0458] Here, it may be considered that the UE has received an allowed NSSAI from the network after the slice replacement has occurred, with the replaced S-NSSAI and / or the alternative S-NSSAI set to on-demand S-NSSAI.

[0459] 1. If the replaced S-NSSAI is deleted from the allowed NSSAI.

[0460] If the UE receives an allowed NSSAI with a replaced S-NSSAI deleted, the UE may delete any stored mapping information between the replaced S-NSSAI and the replacement S-NSSAI (e.g., an entry containing the replaced S-NSSAI or the replacement S-NSSAI). If there was a running timer (slice deregistration inactivity timer) for the replaced S-NSSAI, the UE may stop and reset the timer.

[0461] The network may send the UE an allowed NSSAI without deleting the alternate S-NSSAI from the allowed NSSAI. In this case, if the alternate S-NSSAI is an on-demand S-NSSAI and the associated PDU Session of the alternate S-NSSAI has not been established, the UE may allow the slice deregistration inactivity timer, if any, to run for the alternate S-NSSAI.

[0462] 2. If the replacement S-NSSAI is deleted from the allowed NSSAI.

[0463] If the UE receives an allowed NSSAI with a deleted replacement S-NSSAI, the UE may delete any stored mapping information between the replaced S-NSSAI and the replacement S-NSSAI (e.g., entries containing the replaced S-NSSAI or the replacement S-NSSAI). If there was a running timer for the replacement S-NSSAI (slice deregistration inactivity timer), the UE may stop and reset the timer.

[0464] Additionally, configured NSSAI information updates of the terminal can be performed without signaling received from the network.

[0465] When the terminal receives slice replacement information (e.g., replacement S-NSSAI), if it also receives a configured NSSAI with the replacement S-NSSAI added, the terminal may indicate in the configured NSSAI information storage context that the replacement S-NSSAI is an addition to the slice replacement operation. Thereafter, when the mapping information between the replacement S-NSSAI and the replaced S-NSSAI is deleted, the terminal may delete the replacement S-NSSAI from the configured NSSAI.

[0466] III. First Example

[0467] The UE and the network may locally delete the stored mapping information between the replaced S-NSSAI and the alternative S-NSSAI (e.g., an entry containing the replaced S-NSSAI or the alternative S-NSSAI).

[0468] The UE and the network may delete an entry (see FIG. 13) containing an S-NSSAI whose mapping information should be deleted from among the stored alternative NSSAI information.

[0469] 1. NSSAI storage

[0470] In relation to this content, the provisions of 24.501 v18.7.0 clause 4.6.2.2 may apply.

[0471] When a new allowed NSSAI for a given PLMN or SNPN is received and the allowed NSSAI does not contain a replaced S-NSSAI or a substituted S-NSSAI, the UE may delete the entry containing the replaced S-NSSAI or the substituted S-NSSAI stored in the substituted NSSAI.

[0472] If the UE locally removes the replaced S-NSSAI or the replaced S-NSSAI from its allowed NSSAIs after the associated slice deregistration inactivity timer (e.g., the deregistration inactivity timer associated with the replaced S-NSSAI or the replacement S-NSSAI) expires, the UE may delete the entry containing the replaced S-NSSAI or the replaced S-NSSAI stored in the replacement NSSAI. For example, the UE may delete the entry (the entry containing the replaced S-NSSAI or the replaced S-NSSAI) in the replacement NSSAI.

[0473] 2. Mobility management based on network slice usage control

[0474] In relation to this content, the provisions of 24.501 v18.7.0 clause 4.6.2.9 may apply.

[0475] If AMF determines that the on-demand S-NSSAI should be replaced with a replacement S-NSSAI, AMF may update the on-demand NSSAI and the replacement NSSAI in the REGISTRATION ACCEPT message or the CONFIGURATION UPDATE COMMAND message.

[0476] AMF can provide:

[0477] a) Alternative S-NSSAI included in the allowed NSSAI (if not already included);

[0478] b) An alternative S-NSSAI included in the configured NSSAI (if not already included).

[0479] c) Alternative S-NSSAI included in NSAG information (if not already included and the UE supports NSAG)

[0480] d) A replacement NSSAI containing mapping information between the on-demand S-NSSAI to be replaced and the corresponding replacement S-NSSAI.

[0481] e) On-demand NSSAI containing the latest on-demand NSSAI information;

[0482] When an on-demand S-NSSAI is replaced by another on-demand S-NSSAI and the slice deregistration inactivity timer for the replaced S-NSSAI is running, the following can be done:

[0483] - If a slice deregistration inactivity timer is configured for the replacement on-demand S-NSSAI, the AMF and the UE may stop the slice deregistration inactivity timer for the replaced on-demand S-NSSAI.

[0484] - If a slice deregistration inactivity timer is configured for a replacement on-demand S-NSSAI, and no PDU session associated with the replacement S-NSSAI is established, the AMF and the UE may start the slice deregistration inactivity timer for the replacement S-NSSAI. The timer value may be set to the remaining value of the slice deregistration inactivity timer of the replaced on-demand S-NSSAI. Alternatively, the slice deregistration inactivity timer for the replacement S-NSSAI, if already running, may continue to run.

[0485] - If the slice deregistration inactivity timer is not configured for the replacement S-NSSAI, the AMF and the UE may stop the slice deregistration inactivity timer for the replaced on-demand S-NSSAI.

[0486] If an on-demand S-NSSAI is replaced by another on-demand S-NSSAI, and the slice deregistration inactivity timer for the replaced S-NSSAI is not running and the slice deregistration inactivity timer for the replacement S-NSSAI is running, then the AMF and the UE may stop and reset the slice deregistration inactivity timer for the replacement S-NSSAI when a PDU session is associated with the replacement S-NSSAI.

[0487] If the replaced S-NSSAI becomes available again, the UE and AMF may set the value of the slice deregistration inactivity timer for the replaced S-NSSAI to the remaining value of the slice deregistration inactivity timer for the replacement S-NSSAI.

[0488] IV. Second Example

[0489] Network slice usage control and network slice replacement features are introduced.

[0490] The network can replace a configurable on-demand S-NSSAI with an alternate S-NSSAI after the associated PDU session is established for network slice usage control functionality.

[0491] To enable the serving network to guide the UE to its preferred network slice, the AMF may request the UE to transfer a PDU session from one S-NSSAI to another S-NSSAI.

[0492] It is unclear how the UE and AMF behavior can be implemented when an S-NSSAI is replaced by a replacement S-NSSAI, and one or both of the S-NSSAIs are on-demand S-NSSAIs. For example, it is unclear how to handle the slice deregistration inactivity timer when a PDU session is transferred, and whether to maintain mapping information between the replaced S-NSSAI and the replacement S-NSSAI when the slice deregistration inactivity timer expires.

[0493] The following is described below:

[0494] - Slice replacement scenarios to consider

[0495] - Expected UE / network behavior when the replaced network slice becomes available again.

[0496] 1. Slice Replacement Scenarios to Consider

[0497] When a PDU session associated with an on-demand S-NSSAI is established, the AMF can perform a slice replacement to transfer the PDU session to another S-NSSAI. There may be no restrictions on the type of S-NSSAI to which the PDU session is transferred (e.g., on-demand S-NSSAI, non-on-demand S-NSSAI). Therefore, three cases A, B, and C described below can be considered for slice replacement involving an on-demand S-NSSAI.

[0498] AMF may provide a UE that supports network slice replacement with an NSSAI configured and an alternate S-NSSAI in the allowed NSSAIs. If an alternate S-NSSAI is removed from the allowed NSSAIs, slice replacement may no longer be available.

[0499] Observation 1: Replaced S-NSSAI and alternative S-NSSAI may be included in the allowed NSSAI.

[0500] If the replaced S-NSSAI is no longer valid or cannot be reused, the AMF may remove the replacement S-NSSAI from the allowed NSSAIs.

[0501] The substitute S-NSSAI does not belong to the subscribed S-NSSAI,

[0502] a) the replaced S-NSSAI is removed from the allowed NSSAI or partially allowed NSSAI, or

[0503] b) If the replaced S-NSSAI is available again,

[0504] AMF may provide the UE with the updated allowed NSSAI or partially allowed NSSAI, excluding the replacement S-NSSAI, during the UE configuration update procedure or registration procedure.

[0505] Observation 2: If the mapping between the replaced S-NSSAI and the alternate S-NSSAI is no longer required, the alternate S-NSSAI can be excluded from the allowed NSSAIs.

[0506] Based on Observation 1 and Observation 2, if the on-demand S-NSSAI is removed locally from the allowed NSSAI due to expiration of the associated slice deregistration inactivity timer, the slice replacement mapping between the replaced S-NSSAI and the alternate S-NSSAI may not need to be maintained. Therefore, it may be proposed to remove the mapping information of the stored alternate NSSAI when the slice deregistration inactivity timer expires and the associated S-NSSAI is removed locally from the allowed NSSAI.

[0507] If a UE locally removes a replaced S-NSSAI or a replacement S-NSSAI from its allowed NSSAI when the associated S-NSSAI expires, the UE may remove the mapping information between the replaced S-NSSAI and the replacement S-NSSAI from its stored replacement NSSAI.

[0508] 1) Case A. When the replaced S-NSSAI is an on-demand S-NSSAI and the replacement S-NSSAI is not an on-demand S-NSSAI.

[0509] When all PDU sessions using the replaced S-NSSAI are replaced with the alternate S-NSSAI, the question arises whether the UE should start a slice deregistration inactivity timer for the replaced S-NSSAI.

[0510] When the slice deregistration inactivity timer expires, the UE and AMF must locally remove the replaced S-NSSAI from the allowed NSSAIs. The UE must then delete the stored mapping information between the replaced S-NSSAI and the replacement S-NSSAI.

[0511] This will be described later.

[0512] 1-1)

[0513] The slice deregistration inactivity timer associated with a replaced S-NSSAI may not start.

[0514] When all PDU sessions using the replacement S-NSSAI are released, a slice deregistration inactivity timer associated with the replaced S-NSSAI may be started.

[0515] The above-described actions can be performed by the UE or the AMF.

[0516] 1-2)

[0517] When the slice deregistration inactivity timer expires, the replaced S-NSSAI may be locally removed from the allowed NSSAIs. Furthermore, the mapping information stored between the replacement S-NSSAI and the replaced S-NSSAI may be deleted.

[0518] The above-described actions can be performed by the UE or the AMF.

[0519] 2) Case B. If the replaced S-NSSAI is not an on-demand S-NSSAI and the replacement S-NSSAI is an on-demand S-NSSAI.

[0520] The question arises whether the UE should stop the running slice deregistration inactivity timer for the alternate S-NSSAI when the PDU session is transferred to the S-NSSAI.

[0521] This will be described later.

[0522] 2-1)

[0523] If the slice deregistration inactivity timer associated with the replacement S-NSSAI is running when replacing a slice, that timer may be stopped.

[0524] The above-described actions can be performed by the UE or the AMF.

[0525] 2-2)

[0526] When the last PDU session associated with the alternate S-NSSAI is released, the slice deregistration inactivity timer associated with the alternate S-NSSAI may be started.

[0527] The above-described actions can be performed by the UE or the AMF.

[0528] 2-3)

[0529] When the slice deregistration inactivity timer expires, the alternate S-NSSAI may be locally removed from the allowed NSSAIs. Furthermore, the mapping information stored between the alternate S-NSSAI and the replaced S-NSSAI may be deleted.

[0530] The above-described actions can be performed by the UE or the AMF.

[0531] 3) Case C. When both the replaced S-NSSAI and the replacement S-NSSAI are on-demand S-NSSAI.

[0532] If the slice deregistration inactivity timer is running for the replaced S-NSSAI and / or alternate S-NSSAI, the question arises as to how to handle the slice deregistration inactivity timer.

[0533] This will be described later.

[0534] 3-1)

[0535] If the slice deregistration inactivity timer for the replaced S-NSSAI is running and no PDU sessions associated with the replaced S-NSSAI are established:

[0536] - Set the slice deregistration inactivity timer value for the replacement S-NSSAI to the remaining value of the slice deregistration inactivity timer for the replaced S-NSSAI and start the timer.

[0537] - If the slice deregistration inactivity timer for the alternative S-NSSAI is running, keep the timer running.

[0538] - When the first PDU session associated with the replacement S-NSSAI is established, stop the slice deregistration inactivity timer for the replaced S-NSSAI.

[0539] The above-described actions can be performed by the UE or the AMF.

[0540] 3-2)

[0541] If the slice deregistration inactivity timer for the replaced S-NSSAI is not running and the slice deregistration inactivity timer for the replacement S-NSSAI is running, the UE (or AMF) may stop and reset the slice deregistration inactivity timer for the replaced S-NSSAI. In addition, the UE (or AMF) may not start the slice deregistration inactivity timer for the replaced S-NSSAI.

[0542] 3-3)

[0543] When the slice deregistration inactivity timer expires, the UE (or AMF) may locally remove the associated S-NSSAI from the allowed NSSAI. In addition, the UE (or AMF) may delete the stored mapping information between the replacement S-NSSAI of the replacement NSSAI and the replaced S-NSSAI.

[0544] 2. Expected UE / network behavior when the replaced network slice becomes available again.

[0545] When the replaced S-NSSAI becomes available again, AMF can explicitly update the replacement NSSAI via a registration accept message or a configuration update command message.

[0546] If the AMF determines that the replaced S-NSSAI is available for reuse, the AMF may provide the UE with the updated replacement NSSAI, excluding the replaced S-NSSAI and its replacement S-NSSAI, during the UE configuration update procedure or the registration procedure.

[0547] The UE can update the stored alternate NSSAI with the latest alternate NSSAI received from the network. Therefore, when the replaced S-NSSAI becomes available again, no further explanation is required regarding the updating of the mapping information between the replaced S-NSSAI and the alternate S-NSSAI.

[0548] When a replaced S-NSSAI becomes available again and the AMF explicitly updates the replacement NSSAI, the AMF may update the allowed NSSAIs as needed.

[0549] In the case of Case A described above, if the replaced S-NSSAI is used again, the slice deregistration inactivity timer is not executed when the network slice is replaced, so the UE and network operations can be applied as conventional operations.

[0550] If the replaced S-NSSAI and the replacement S-NSSAI are on-demand S-NSSAIs and the slice deregistration timer for the replacement S-NSSAI is up / running, the UE (or AMF) may set the value of the slice deregistration timer for the replaced S-NSSAI to the remaining value of the slice deregistration timer for the replacement S-NSSAI.

[0551] According to the disclosure of this specification, when a UE (or AMF) replaces a first network slice with a second network slice, it may delete the mapping information (replacement mapping information between the first network slice and the second network slice) when a timer (slice deregistration inactivity timer) for at least one of the two network slices expires.

[0552] According to the disclosure of this specification, when a first network slice is replaced with a second network slice, if the UE receives an allowed NSSAI in which at least one of the two network slices is deleted, the UE may delete the mapping information (the replacement mapping information between the first network slice and the second network slice).

[0553] According to the implementation of this specification, a terminal can transmit accurate PDU session connection request information to the network without considering invalid alternative NSSAI information. This can prevent unnecessary signaling and temporary service interruption.

[0554] Based on URSP rules or UE local configuration, a terminal may include a PDU session type information element (IE) in a PDU session establishment request message. Conventionally, a terminal performs a PDU session establishment request based on incorrect information (e.g., inter-slice mapping information containing information about a slice that should have been deleted due to a timer (e.g., a network slice identifier). This may result in unnecessary operations (e.g., re-establishment by a PDU session modification procedure, additional procedures, or signaling). Furthermore, temporary service interruption may occur. According to the embodiments of the present disclosure, these problems can be solved.

[0555] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0556] Figure 17 illustrates the UE's procedure for disclosure of this specification.

[0557] 1. Based on the expiration of the slice deregistration timer associated with the replaced S-NSSAI (Single-Network Slice Selection Assistance Information) or alternative S-NSSAI, the UE (User Equipment) may delete the replaced S-NSSAI or alternative S-NSSAI from the allowed NSSAI.

[0558] 2. Based on the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAI, the UE may delete an entry containing the replaced S-NSSAI or the alternative S-NSSAI from the alternative NSSAI.

[0559] The above replacement S-NSSAI may be an S-NSSAI that is switched from the replaced S-NSSAI by replacing a network slice.

[0560] The UE may start the slice deregistration timer for the replaced S-NSSAI or the alternative S-NSSAI.

[0561] The step of the UE starting the slice deregistration timer may be performed before the step of the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAI.

[0562] The step of starting the above slice deregistration timer may be performed based on at least one of the replaced S-NSSAI and the alternative S-NSSAI corresponding to an on-demand NSSAI.

[0563] The step of starting the slice deregistration timer may include: a step of the UE starting the slice deregistration timer for the replaced S-NSSAI based on whether the replaced S-NSSAI corresponds to an on-demand NSSAI; and a step of the UE starting the slice deregistration timer for the replaced S-NSSAI based on whether the replaced S-NSSAI corresponds to an on-demand NSSAI.

[0564] The step of starting the above slice deregistration timer may be performed based on the fact that all PDU sessions related to the network slice corresponding to the On-demand NSSAI among the above replaced S-NSSAI and the above alternative S-NSSAI are released.

[0565] Based on the expiration of the above slice deregistration timer, the UE may delete mapping information between the replaced S-NSSAI and the alternative S-NSSAI.

[0566] Based on the re-availability of the replaced S-NSSAI, the UE may start the slice deregistration timer for the replaced S-NSSAI with the remaining value of the slice deregistration timer for the replacement S-NSSAI.

[0567] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0568] Figure 18 illustrates the AMF's procedure for the disclosure of this specification.

[0569] 1. Based on the expiration of the slice deregistration timer associated with a replaced S-NSSAI (Single-Network Slice Selection Assistance Information) or an alternative S-NSSAI, the Access and Mobility Management Function (AMF) may delete the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAIs.

[0570] 2. Based on the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAI, the AMF may delete an entry containing the replaced S-NSSAI or the alternative S-NSSAI from the alternative NSSAI.

[0571] The above replacement S-NSSAI may be an S-NSSAI that is switched from the replaced S-NSSAI by replacing a network slice.

[0572] The above AMF may start the slice deregistration timer for the above replaced S-NSSAI or the above replacement S-NSSAI.

[0573] The step of the AMF starting the slice deregistration timer may be performed before the step of the AMF deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAIs.

[0574] The step of starting the above slice deregistration timer may be performed based on at least one of the replaced S-NSSAI and the alternative S-NSSAI corresponding to an on-demand NSSAI.

[0575] The step of starting the slice deregistration timer may include: a step in which the AMF starts the slice deregistration timer for the replaced S-NSSAI based on whether the replaced S-NSSAI corresponds to an on-demand NSSAI; and a step in which the AMF starts the slice deregistration timer for the replaced S-NSSAI based on whether the replaced S-NSSAI corresponds to an on-demand NSSAI.

[0576] The step of starting the above slice deregistration timer may be performed based on the fact that all PDU sessions related to the network slice corresponding to the On-demand NSSAI among the above replaced S-NSSAI and the above alternative S-NSSAI are released.

[0577] Based on the expiration of the above slice deregistration timer, the AMF may delete mapping information between the replaced S-NSSAI and the alternative S-NSSAI.

[0578] Based on the re-availability of the replaced S-NSSAI, the AMF may start the slice deregistration timer for the replaced S-NSSAI with the remaining value of the slice deregistration timer for the replacement S-NSSAI.

[0579] Hereinafter, a device for performing communication according to some embodiments of the present specification will be described.

[0580] For example, a device may include a processor, a transceiver, and memory.

[0581] For example, a processor may be configured to be operatively coupled with memory and a processor.

[0582] The operations performed by the processor include: a step of, based on expiration of a slice deregistration timer associated with a replaced S-NSSAI (Single-Network Slice Selection Assistance Information) or an alternative S-NSSAI, deleting, by a UE (User Equipment), the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs; a step of, based on the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs, deleting, by the UE, an entry including the replaced S-NSSAI or the alternative S-NSSAI from an alternative NSSAI, wherein network slice replacement from the replaced S-NSSAI to the alternative S-NSSAI can be performed.

[0583] Below, a processor of a device for providing communication according to some embodiments of the present specification is described.

[0584] The operations performed by the processor include: a step of, based on expiration of a slice deregistration timer associated with a replaced S-NSSAI (Single-Network Slice Selection Assistance Information) or an alternative S-NSSAI, deleting, by a UE (User Equipment), the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs; a step of, based on the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs, deleting, by the UE, an entry including the replaced S-NSSAI or the alternative S-NSSAI from an alternative NSSAI, wherein network slice replacement from the replaced S-NSSAI to the alternative S-NSSAI can be performed.

[0585] Hereinafter, a non-volatile computer-readable medium storing one or more commands for providing mobile communication according to some embodiments of the present specification is described.

[0586] According to some embodiments of the present disclosure, the technical features of the present disclosure may be implemented directly in hardware, software executed by a processor, or a combination of the two. For example, a method performed by a wireless device in wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or other storage media.

[0587] Some examples of storage media are coupled to the processor, allowing the processor to read information from the storage media. Alternatively, the storage media may be integrated into the processor. The processor and storage media may reside in an ASIC. In other examples, the processor and storage media may reside as separate components.

[0588] Computer-readable media may include tangible and non-volatile computer-readable storage media.

[0589] For example, nonvolatile computer-readable media may include random access memory (RAM), such as synchronized dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), read-only memory (EEPROM), flash memory, magnetic or optical data storage media, or any other media that can be used to store instructions or data structures. Nonvolatile computer-readable media may also include combinations of the above.

[0590] Additionally, the methods described herein can be realized at least in part by a computer-readable communication medium that carries or transmits code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0591] According to some embodiments of the present disclosure, a non-transitory computer-readable medium has one or more instructions stored thereon. The one or more stored instructions can be executed by a processor of a base station.

[0592] The stored one or more commands include: a step of, based on expiration of a slice deregistration timer associated with a replaced Single-Network Slice Selection Assistance Information (S-NSSAI) or an alternative S-NSSAI, deleting, by a User Equipment (UE), the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs; a step of, based on the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from allowed NSSAIs, deleting, by the UE, an entry including the replaced S-NSSAI or the alternative S-NSSAI from an alternative NSSAI, wherein network slice replacement from the replaced S-NSSAI to the alternative S-NSSAI can be performed.

[0593] Hereinafter, a non-volatile computer-readable medium storing one or more commands for providing mobile communication according to some embodiments of the present specification is described.

[0594] This specification may have various effects.

[0595] For example, through the procedures disclosed herein, a QoS policy suitable for a non-3GPP device connected to a terminal can be applied.

[0596] The effects that can be achieved through specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0597] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a method. Other implementations are within the scope of the claims.

Claims

1. As a method, A step of a UE (User Equipment) deleting the replaced S-NSSAI (Single-Network Slice Selection Assistance Information) or the alternative S-NSSAI from allowed NSSAIs based on expiration of a slice deregistration timer associated with the replaced S-NSSAI or the alternative S-NSSAI; A step of the UE deleting an entry including the replaced S-NSSAI or the replaced S-NSSAI from the replaced NSSAI based on the UE deleting the replaced S-NSSAI or the replaced S-NSSAI from the allowed NSSAI, A method in which the above-mentioned replacement S-NSSAI is an S-NSSAI that is switched from the above-mentioned replaced S-NSSAI by replacing a network slice.

2. In paragraph 1, The UE further comprises a step of starting the slice deregistration timer for the replaced S-NSSAI or the alternative S-NSSAI, The step of the UE starting the slice deregistration timer is performed before the step of the UE deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAI.

3. In paragraph 2, The steps to start the above slice deregistration timer are: A method performed based on at least one of the above-mentioned replaced S-NSSAI and the above-mentioned alternative S-NSSAI corresponding to an on-demand NSSAI.

4. In paragraph 2, The steps to start the above slice deregistration timer are: A step in which the UE starts the slice deregistration timer for the replaced S-NSSAI based on the fact that the replaced S-NSSAI corresponds to an on-demand NSSAI; and A method comprising a step of the UE starting the slice deregistration timer for the alternative S-NSSAI based on the alternative S-NSSAI corresponding to the on-demand NSSAI.

5. In any one of the clauses 2 to 4, The steps to start the above slice deregistration timer are: A method performed based on releasing all PDU sessions related to the network slice corresponding to the On-demand NSSAI among the above-mentioned replaced S-NSSAI and the above-mentioned alternative S-NSSAI.

6. In any one of paragraphs 1 to 5, A method further comprising a step of the UE deleting mapping information between the replaced S-NSSAI and the alternative S-NSSAI based on the expiration of the slice deregistration timer.

7. In any one of paragraphs 1 to 6, A method further comprising the step of the UE starting a slice deregistration timer for the replaced S-NSSAI with the remaining value of the slice deregistration timer for the replacement S-NSSAI based on the re-availability of the replaced S-NSSAI.

8. As a method, A step of an Access and Mobility Management Function (AMF) deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAIs based on the expiration of a slice deregistration timer associated with the replaced S-NSSAI or the alternative S-NSSAI; A step in which the AMF deletes an entry including the replaced S-NSSAI or the replaced S-NSSAI from the replaced NSSAI based on the UE deleting the replaced S-NSSAI or the replaced S-NSSAI from the allowed NSSAI, A method in which the above-mentioned replacement S-NSSAI is an S-NSSAI that is switched from the above-mentioned replaced S-NSSAI by replacing a network slice.

9. In paragraph 8, The AMF further comprises a step of starting the slice deregistration timer for the replaced S-NSSAI or the alternative S-NSSAI, The step of the AMF starting the slice deregistration timer is performed before the step of the AMF deleting the replaced S-NSSAI or the alternative S-NSSAI from the allowed NSSAIs.

10. In paragraph 9, The steps to start the above slice deregistration timer are: A method performed based on at least one of the above-mentioned replaced S-NSSAI and the above-mentioned alternative S-NSSAI corresponding to an on-demand NSSAI.

11. In paragraph 9, The steps to start the above slice deregistration timer are: A step in which the AMF starts the slice deregistration timer for the replaced S-NSSAI based on the fact that the replaced S-NSSAI corresponds to an on-demand NSSAI; and A method comprising the step of the AMF starting the slice deregistration timer for the alternative S-NSSAI based on the alternative S-NSSAI corresponding to the On-demand NSSAI.

12. In any one of the clauses 9 to 11, The steps to start the above slice deregistration timer are: A method performed based on releasing all PDU sessions related to the network slice corresponding to the On-demand NSSAI among the above-mentioned replaced S-NSSAI and the above-mentioned alternative S-NSSAI.

13. In any one of the clauses 8 to 12, A method further comprising a step of the AMF deleting mapping information between the replaced S-NSSAI and the alternative S-NSSAI based on the expiration of the slice deregistration timer.

14. In any one of the clauses 8 to 13, A method further comprising the step of the AMF starting the slice deregistration timer for the replaced S-NSSAI with the remaining value of the slice deregistration timer for the replacement S-NSSAI based on the re-availability of the replaced S-NSSAI.

15. As a UE (User Equipment) performing communication, At least one transmitter and receiver; Contains at least one processor, A UE wherein the operation performed by at least one processor is a method according to any one of claims 1 to 7.

16. As an AMF (Access and Mobility Management Function) that performs communication, At least one transmitter and receiver; Contains at least one processor, The operation performed by said at least one processor is an AMF method according to any one of claims 8 to 14.

17. As an apparatus in mobile communication, at least one processor; and At least one memory storing instructions and being operably electrically connected to the at least one processor, A device wherein the operation performed based on the command being executed by the at least one processor is a method according to any one of claims 1 to 7.

18. A non-volatile computer-readable storage medium that records commands, A non-volatile computer-readable storage medium, wherein the instructions, when executed by one or more processors, cause the one or more processors to perform an operation according to any one of claims 1 to 7.

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