Communication related to af request

Abstract

One disclosure of the present specification provides a method by which an NEF performs communication. The method may comprise the steps of: transmitting, to a BSF, a management search message including both S-NSSAI and alternative S-NSSAI; receiving, from the BSF, information related to a second PCF which satisfies both the S-NSSAI and the alternative S-NSSAI and serves a PDU session of a UE; and transmitting, to the second PCF, a policy authentication message for updating QoS.

Description

Communication related to AF requests

[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, meeting both urgent market needs and the longer-term requirements outlined by the ITU Radio communication sector (ITU-R) 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] The operation related to slice replacement is being discussed. However, there is a problem in that slice replacement according to AF request cannot be supported according to the prior art.

[0006] According to one embodiment of the present disclosure, a method for an NEF to perform communication is provided. The method may include: receiving a policy authentication request message for slice replacement from an AF; transmitting a management subscription message including information related to the UE to a BSF; receiving a management notification message including information related to a first PCF serving the UE from the BSF; transmitting a policy authentication message including information related to the UE and information related to the slice replacement to the first PCF serving the UE; receiving a QoS creation message including an S-NSSAI and an alternate S-NSSAI from the AF; and transmitting a management discovery message including both an S-NSSAI and an alternate S-NSSAI to the BSF; receiving information related to a second PCF that satisfies both the S-NSSAI and the alternate S-NSSAI and serves the PDU session of the UE from the BSF; and transmitting a policy authentication message for QoS update to the second PCF.

[0007] According to one embodiment, a device implementing the method is provided.

[0008] According to one embodiment of the present disclosure, a method for a PCF to perform communication is provided. The method may include the steps of receiving a message related to an SM policy association from an SMF; and registering both an S-NSSAI and an Alternative S-NSSAI with a BSF.

[0009] According to one embodiment, a device implementing the method is provided.

[0010] According to one embodiment of the present disclosure, a method for an AMF to perform communication is provided. The method may include: receiving an update notification message from a PCF, the update notification message including information to replace an S-NSSAI of a PDU session of the UE with a replacement S-NSSAI; transmitting a message related to a UE configuration update including the mapping information to the UE; and transmitting a context update message to an SMF, the context update message including information to request replacing an S-NSSAI of the PDU session with the replacement S-NSSAI.

[0011] According to one embodiment, a device implementing the method is provided.

[0012] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0013] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0014] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0015] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0016] FIG. 5a and FIG. 5b illustrate an example of a PDU session establishment procedure according to one embodiment of the disclosure of the present specification.

[0017] FIGS. 6A and 6B illustrate an example of a procedure related to slice replacement according to one embodiment of the disclosure of the present specification.

[0018] FIG. 7 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0019] 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 Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems. CDMA can be implemented using wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using 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 Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) Long-Term Evolution (LTE) is part of E-UMTS (Evolved UMTS) that utilizes 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).

[0020] 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, but aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0021] 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.

[0022] As used herein, "A or B" can mean "only A," "only B," or "both A and B." In other words, 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."

[0023] 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."

[0024] 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.”

[0025] 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”.

[0026] 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."

[0027] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0028] 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).

[0029] 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.

[0030] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0031] 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.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] The wireless devices (100a to 100f) represent 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. The wireless devices (100a to 100f) may include, but are not limited to, a robot (100a), a vehicle (100b-1 and 100b-2), an extended reality (XR) device (100c), a portable device (100d), a home appliance (100e), an Internet-of-Things (IoT) device (100f), and an artificial intelligence (AI) device / server (400). For example, the vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. The vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of HMD (Head-Mounted Device) and HUD (Head-Up Display) 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.

[0036] 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 function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram 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.

[0037] 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).

[0038] 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, D2D (Device-To-Device) communication), and base station-to-base station communication (150c) (e.g., relay, IAB (Integrated Access and Backhaul)). 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, based on various proposals of the present specification, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed.

[0039] NR supports multiple numerologies, or subcarrier spacings (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.

[0040] 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 the NR system, FR1 can mean the "sub 6 GHz range," and FR2 can mean the "above 6 GHz range," which can be called millimeter wave (mmW).

[0041] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0042] 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 may be used for various purposes, such as for communications for vehicles (e.g., autonomous driving).

[0043] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0044] 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 PANs (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.

[0045] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0046] 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.

[0047] 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).

[0048] 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).

[0049] 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).

[0050] 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.

[0051] 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.

[0052] 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).

[0053] 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).

[0054] 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).

[0055] 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 code, instructions 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.

[0056] 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.

[0057] 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.

[0058] 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. 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.One or more memories (104, 204) may be located internally and / or externally to one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0059] 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.

[0060] 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 disclosure, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0061] 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).

[0062] 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.

[0063] In the implementation of this specification, a UE can operate as a transmitter in the uplink and as a receiver in the downlink. In the implementation of this 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 this specification or to control a transceiver (106) to perform UE operations according to the implementation of this 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 this specification or to control a transceiver (206) to perform base station operations according to the implementation of this specification.

[0064] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0065] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0066] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0067] 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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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).

[0073] 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.

[0074] 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).

[0075] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0076] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0077] - AUSF (Authentication Server Function)

[0078] -AMF (Access and Mobility Management Function)

[0079] - DN (Data Network), for example, operator services, Internet access, or third-party services.

[0080] - USDF (Unstructured Data Storage Function)

[0081] - NEF (Network Exposure Function)

[0082] - I-NEF (Intermediate NEF)

[0083] - NRF (Network Repository Function)

[0084] - NSSF (Network Slice Selection Function)

[0085] - PCF (Policy Control Function)

[0086] - SMF (Session Management Function)

[0087] - UDM (Unified Data Management)

[0088] - UDR (Unified Data Repository)

[0089] - UPF (User Plane Function)

[0090] - UCMF (UE radio Capability Management Function)

[0091] - AF (Application Function)

[0092] - UE (User Equipment)

[0093] - (R)AN ((Radio) Access Network)

[0094] - 5G-EIR (5G-Equipment Identity Register)

[0095] - NWDAF (Network Data Analytics Function)

[0096] - CHF (CHarging Function)

[0097] 또한, 다음과 같은 네트워크 기능이 고려될 수 있다.

[0098] - N3IWF (Non-3GPP InterWorking Function)

[0099] - TNGF (Trusted Non-3GPP Gateway Function)

[0100] - W-AGF (Wireline Access Gateway Function)

[0101] Figure 4 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0102] For clarity of the point-to-point diagram in Figure 4, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0103] 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.

[0104] The 5G system architecture includes the following benchmarks:

[0105] - N1: Reference point between UE and AMF.

[0106] - N2: Reference point between (R)AN and AMF.

[0107] - N3: Reference point between (R)AN and UPF.

[0108] - N4: Reference point between SMF and UPF.

[0109] - N6: Reference point between UPF and data network.

[0110] - N9: Reference point between two UPFs.

[0111] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0112] - N5: Reference point between PCF and AF.

[0113] - N7: Reference point between SMF and PCF.

[0114] - N8: Reference point between UDM and AMF.

[0115] - N10: Reference point between UDM and SMF.

[0116] - N11: Reference point between AMF and SMF.

[0117] - N12: Reference point between AMF and AUSF.

[0118] - N13: Reference point between UDM and AUSF.

[0119] - N14: Reference point between two AMFs.

[0120] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0121] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0122] - N22: Reference point between AMF and NSSF.

[0123] In some cases, two NFs may need to be interconnected to serve a UE.

[0124] In 5GS, the S-NSSAI used by PDU Sessions can be replaced with Alternative S-NSSAI. CR S2-2307560 was approved at the SA2#157 meeting (May 2023). According to this CR, when a slice replacement occurs for a PDU Session, the network can notify AF.

[0125] For example, PCF can perform event reporting.

[0126] An AF can subscribe to / unsubscribe from a PCF's event notifications for the PDU sessions to which the AF session is connected. An AF can subscribe / unsubscribe directly to a PCF or indirectly via NEF or TSCTSF (Time Sensitive Communication and Time Synchronization Function).

[0127] A PCF for a UE can subscribe / unsubscribe to PCF event notifications for the UE's PDU sessions. Other NFs can subscribe / unsubscribe to PCF event notifications for PDU sessions or UEs.

[0128] Examples of events that AF and other NFs can join are shown in Table 3.

[0129] Event Description Availability of NFRx PDU Sessions for Subscription Reporting Availability of N5 per PDU Session Availability of Bulk Subscriptions Availability of N43 based on SUPI, DNN, and S-NSSAI Availability of N5 per UE Availability of N24 per UE Network Slice Replacement When a PDU session changes from an S-NSSAI to a replacement S-NSSAI, PCF reports the replacement S-NSSAI. PCFNoYesNoYesNoNo

[0130] Table 3 shows examples of events related to reporting by PCF. Availability for N5 per PDU Session may mean that information reporting events for PDU sessions are available between PCF and AF.

[0131] Note that Table 3 only includes events related to network slice replacement (or replacement) relevant to the disclosure of this specification, but this is for illustrative purposes only. For events not included in Table 3, 3GPP TS 23.503 V18.0.0 Table 6.1.3.18-1 may be applied.

[0132] A request for a network slice replacement (or replacement) report triggers PCF to report when it receives a network slice replacement from SMF. When PCF receives a subscription (or subscriptions) for this event, if it has not already subscribed (or subscribed), it sets the corresponding Policy Control Request Trigger in SMF.

[0133] For example, AF can subscribe to network slice replacement reporting. In this case, when PCF receives a network slice replacement notification from SMF, PCF can notify AF of the network slice replacement.

[0134] Meanwhile, as described in 3GPP TS 23.501 V18.0.0 clause 5.15.19, replacement may be performed before a PDU Session is created, or slice replacement may be performed for an already created PDU Session. In addition, when slice replacement is performed for an already created PDU Session, the existing PDU Session may be maintained, or the existing PDU Session may be released and a new PDU Session may be created.

[0135] Additionally, according to 3GPP TS 23.503 V18.0.0 clause 6.1.3.29, the SMF can report Alternative S-NSSAI to the PCF only if the PDU Session is maintained as follows:

[0136] An example of network slice replacement for an existing PDU session is described. Note that in the disclosure of this specification, the term "network slice replacement" may be used interchangeably with "network slice replacement."

[0137] For network slice replacement, see section 5.15.19 of TS 23.501 V18.0.0.

[0138] PCF can set a network slice replacement trigger event in SMF as defined in TS 23.503 V18.0.0 section 6.1.3.5.

[0139] When an existing PDU session is migrated from an S-NSSAI to an alternative S-NSSAI, the SMF may determine that the existing PDU session and its existing SM policy association can be maintained (e.g., the SMF may determine that the same PCF can be used for the alternative S-NSSAI). In this case, the SMF updates the S-NSSAI of the PDU session by including the alternative S-NSSAI in the SM policy association modification request to the PCF. The PCF may request subscription information related to the alternative S-NSSAI from the UDR. The PCF may then make policy decisions based on the alternative S-NSSAI and provide the updated PCC rules to the SMF. The PCF may update the binding information of the BSF.

[0140] According to the prior art described above, there is a problem in that the 5G Core (5GC) cannot inform the AF of the Alternative S-NSSAI when a new PDU Session is created. In addition, if a replacement occurs before the PDU Session is created, the AF provides the old S-NSSAI with the replacement as input information to the 5GC, which causes the AF's request to not be properly processed.

[0141] In the prior art, a procedure for performing slice replacement was defined due to issues within 5GC (e.g., congestion). Discussions also took place regarding whether AF should be notified of replaced slice information (Alternative S-NSSAI). When AF requests QoS, etc. from 5GC, AF can also provide slice information. However, if AF provides original slice information before slice replacement in the event of slice replacement, there is a problem of not being able to find the PCF managing the corresponding PDU session. Instead of 5GC notifying AF of slice replacement, BSF stores only the original slice information without storing the Alternative S-NSSAI. In this case, operation may proceed without problems even if AF provides the original slice information.

[0142] Slice replacement can also be performed by AF request. In this case, rather than performing replacement due to an internal issue in 5GC, AF directly requests slice replacement. Unlike the previous situation, AF may be aware that slice replacement is being performed. Therefore, when AF requests QoS, etc. from 5GC, it may transmit a slice containing Alternative S-NSSAI while providing slice information. However, according to Rel-18, BSF does not store Alternative S-NSSAI information, which poses a problem in that BSF cannot process AF's request.

[0143] The AF's behavior for requesting slice replacement is being discussed. When a slice is changed, the AF sends an Alternative S-NSSAI when requesting information such as QoS from the 5GC. However, the prior art has a problem in that the BSF cannot detect whether a slice has been changed.

[0144] This specification proposes the following methods to address the problem. The methods presented below may be performed or used in combination or complementary manner.

[0145] Below, Alternative S-NSSAI can be used interchangeably with Alternative NSSAI, replaced NSSAI, etc.

[0146] Below, various examples of the disclosure of this specification are described.

[0147] An example of how to handle an AF's request for a PDU session based on the Alternative S-NSSAI is provided.

[0148] At meeting SA2#158, it was agreed that network slice replacement is transparent to AF. However, the issue of how to support AF requests without announcing a replacement S-NSSAI remains open, and it was decided to further discuss whether to support AF requests without announcing a replacement S-NSSAI in section 6.1.3.18 of TS 23.503 V18.0.0.

[0149] There are three options that AF can provide input to 5GC:

[0150] Case 1. When AF provides direct input to PCF.

[0151] Case 2. When AF provides input to NEF using DNN / S-NSSAI.

[0152] Case 3. When AF provides input to NEF using AF identifier.

[0153] In Case 1, the AF discovers the PCF using the BSF and provides the DNN / S-NSSAI to find the PCF for the PDU session. Since the AF determines that it does not know the alternate S-NSSAI, it uses the alternate S-NSSAI to find the PCF for the PDU session.

[0154] Observation 1: For Case 1, the AF can find the PCF for the PDU session by providing the replaced S-NSSAI to the BSF.

[0155] For Case 2, the NEF must use the BSF to retrieve the PCF for the PDU session. Since the NEF is unaware of the network slice replacement, it uses the replaced S-NSSAI to retrieve the PCF for the PDU session.

[0156] Observation 2: For Case 2, the NEF can provide the replaced S-NSSAI to the BSF to find the PCF for the PDU session.

[0157] For Case 3, the NEF determines the DNN / S-NSSAI based on the AF identifier and uses the BSF with the determined DNN / S-NSSAI to retrieve the PCF for the PDU session. Since the NEF is unaware of the network slice replacement, it uses the replaced S-NSSAI to retrieve the PCF for the PDU session.

[0158] Observation 3: For Case 3, the NEF can provide the replaced S-NSSAI to the BSF to find the PCF for the PDU session.

[0159] According to the current TS 23.503 specification, when the network performs a network slice replacement, the PCF updates the binding information of the BSF.

[0160] A concrete example of replacing a network slice for an existing PDU session is as follows:

[0161] For network slice replacement, see section 5.15.19 of TS 23.501 V18.0.0.

[0162] PCF can set a network slice replacement trigger event in SMF as defined in TS 23.503 V18.0.0 clause 6.1.3.5.

[0163] When an existing PDU session is migrated from an S-NSSAI to an alternative S-NSSAI, the SMF may determine that the existing PDU session and its existing SM policy association can be maintained (e.g., the SMF may determine that the same PCF can be used for the alternative S-NSSAI). In this case, the SMF updates the S-NSSAI of the PDU session by including the alternative S-NSSAI in the SM policy association modification request to the PCF. The PCF may request subscription information related to the alternative S-NSSAI from the UDR. The PCF may then make policy decisions based on the alternative S-NSSAI and provide the updated PCC rules to the SMF. The PCF may update the binding information of the BSF.

[0164] As understood by the source company, the intent of "PCF may update BSF's binding information" is to update the BSF with an alternative S-NSSAI value. As per Observation 1, Observation 2, and Observation 3, if the PCF uses an alternative S-NSSAI, an additional mechanism is required to process AF requests.

[0165] Observation 4: If the PCF uses an alternate S-NSSAI to update binding information to the BSF, an additional mechanism is required to handle AF requests.

[0166] The question then becomes whether PCF should use an alternate S-NSSAI when updating binding information. According to the source company's understanding, there is no need to use an alternate S-NSSAI in binding information. However, since the actual slice used in a PDU session is an alternate S-NSSAI, it may be useful in future releases to consider using an alternate S-NSSAI when updating binding information.

[0167] Below is what you need to do based on your current specifications for each option.

[0168] Option 1) Use S-NSSAI replaced in binding information.

[0169] In the prior art, a network slice replacement event is reported from the SMF to the PCF only if the PDU session is maintained. When a new PDU session is established using an alternate S-NSSAI, the SMF does not communicate whether the S-NSSAI of the corresponding PDU session is the alternate S-NSSAI. Therefore, the PCF cannot use the alternate S-NSSAI when registering binding information. To support Option 1, this behavior must be changed. That is, when a new PDU session is established, the SMF must notify the PCF of both the replaced S-NSSAI and the alternate S-NSSAI.

[0170] In this option, the PCF sends only the replaced S-NSSAI to the BSF.

[0171] Observation 5: To support Option 1), the SMF must inform the PCF of both the replaced S-NSSAI and the alternative S-NSSAI when a new PDU session is established. The PCF includes only the replaced S-NSSAI when registering binding information with the BSF.

[0172] Option 2) Use alternative S-NSSAI in binding information.

[0173] According to Observation 1, Observation 2 and Observation 3, the BSF must be aware of the alternate S-NSSAI to process AF requests. That is, the BSF must be aware of both the replaced S-NSSAI and the alternate S-NSSAI. Therefore, the SMF must inform the PCF of both the replaced S-NSSAI and the alternate S-NSSAI when a new PDU session is established, so that the PCF can provide both the replaced S-NSSAI and the alternate S-NSSAI to the BSF when registering the binding information.

[0174] In this option, the PCF includes both the replaced S-NSSAI and the replacement S-NSSAI in the BSF.

[0175] Observation 6: To support Option 2), the SMF must notify the PCF of both the replaced S-NSSAI and the replacement S-NSSAI when a new PDU session is established. The PCF includes both the replaced S-NSSAI and the replacement S-NSSAI when registering the binding information with the BSF.

[0176] For both Option 1 and Option 2, the SMF notifies the PCF of both the replaced S-NSSAI and the replacement S-NSSAI. The only difference is whether the replacement S-NSSAI is stored in the binding information. The only difference is whether the BSF stores the replacement S-NSSAI along with the replacement S-NSSAI.

[0177] Proposal 1: You can discuss and choose either Option 1 or Option 2.

[0178] Observation 1: For Case 1, the AF can find the PCF for the PDU session by providing the replaced S-NSSAI to the BSF.

[0179] Observation 2: For Case 2, the NEF can provide the replaced S-NSSAI to the BSF to find the PCF for the PDU session.

[0180] Observation 3: For Case 3, the NEF can provide the replaced S-NSSAI to the BSF to find the PCF for the PDU session.

[0181] Observation 4: If the PCF uses an alternate S-NSSAI to update binding information to the BSF, an additional mechanism is required to handle AF requests.

[0182] Observation 5: To support Option 1), the SMF must inform the PCF of both the replaced S-NSSAI and the alternative S-NSSAI when a new PDU session is established. The PCF includes only the replaced S-NSSAI when registering binding information with the BSF.

[0183] Observation 6: To support Option 2), the SMF must notify the PCF of both the replaced S-NSSAI and the replacement S-NSSAI when a new PDU session is established. The PCF includes both the replaced S-NSSAI and the replacement S-NSSAI when registering the binding information with the BSF.

[0184] proposal:

[0185] (Option 1) If the S-NSSAI is replaced with a replacement S-NSSAI, the SMF provides both the replaced S-NSSAI and the replacement S-NSSAI to the PCF. The PCF uses the replaced S-NSSAI to register / update binding information.

[0186] (Option 2) If the S-NSSAI is replaced with a replacement S-NSSAI, the SMF provides both the replaced S-NSSAI and the replacement S-NSSAI to the PCF. The PCF registers / updates binding information using the replaced S-NSSAI and the replacement S-NSSAI.

[0187] An example of transmitting an alternative S-NSSAI to the PCF during the PDU session establishment procedure is described.

[0188] TS 23.503 V18.0.0 includes a note on how to support AF requests without announcing an alternate S-NSSAI. When the AF provides direct input to the PCF, the AF searches for the PCF through the BSF. Since the AF does not know the alternate S-NSSAI, it always uses the original S-NSSAI and the DNN to find the PCF. Therefore, even if an alternate S-NSSAI is used, the binding information in the BSF must be the S-NSSAI.

[0189] Currently, the alternate S-NSSAI is reported to the PCF only when the existing PDU session is maintained. When a new PDU session is established using the alternate S-NSSAI, the SMF reports the S-NSSAI as the value of the alternate S-NSSAI. Therefore, the PCF cannot determine whether a slice has been replaced.

[0190] Additionally, when establishing a new PDU session using the alternate S-NSSAI, the SMF reports both the S-NSSAI and the alternate S-NSSAI to the PCF.

[0191] If the examples described below are not applied, problems with the prior art cannot be resolved. For example, this problem may include the inability to process AF requests when a PDU session is established using an alternate S-NSSAI.

[0192] Below, examples of PDU session establishment procedures in non-roaming and roaming via local breakout are described. In the PDU session establishment procedures described below, TS 23.502 V18.0.0 4.3.2.2.1 may be referenced for parts not described in this specification. That is, below, the PDU session establishment procedure according to the disclosure of this specification will be described with a focus on differences from TS 23.502 V18.0.0 4.3.2.2.1.

[0193] The PDU session establishment procedure can be used for the following purposes:

[0194] - To establish a new PDU session,

[0195] - To handover the PDN connection of EPS without N26 interface to the PDU session of 5GS,

[0196] - To switch an existing PDU session between a non-3GPP connection and a 3GPP connection, or

[0197] - To request a PDU session for emergency services.

[0198] 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.

[0199] FIG. 5a and FIG. 5b illustrate an example of a PDU session establishment procedure according to one embodiment of the disclosure of the present specification.

[0200] The examples in FIGS. 5a and 5b illustrate UE request PDU session establishment procedures for non-roaming and roaming via local breakout.

[0201] This procedure assumes that the UE is already registered with AMF, so unless the UE is emergency registered, AMF will assume that it has already retrieved the user's subscriber information from UDM.

[0202] 1. The UE sends an NAS message to the AMF. The NAS message may include S-NSSAI(s), [alternative S-NSSAI], UE request DNN, PDU session ID, request type, previous PDU session ID, and N1 SM container (PDU session setup request, [port management information container]).

[0203] 2. The AMF may select an SMF as described in TS 23.501 V18.0.0 sections 6.3.2 and 4.3.2.2.3. If the request type indicates "Initial Request" or the request is due to a handover from an EPS or another AMF-provided non-3GPP connection, the AMF stores the association of the S-NSSAI, DNN, PDU Session ID, SMF ID and connection type of the PDU session. If the AMF decides to replace the S-NSSAI received from the UE with an alternate S-NSSAI, or if the AMF receives an alternate S-NSSAI, the AMF selects an SMF according to the alternate S-NSSAI.

[0204] 3. AMF can send an Nsmf_PDUSession_CreateSMContext request message or an Nsmf_PDUSession_UpdateSMContext request message to SMF.

[0205] The Nsmf_PDUSession_CreateSMContext request message may include SUPI, selected DNN, DNN requested by UE, S-NSSAI(s), [alternative S-NSSAI], PDU session ID, AMF ID, request type, N1 SM container (containing PDU session establishment request), etc.

[0206] The Nsmf_PDUSession_UpdateSMContext request message may include SUPI, DNN, S-NSSAI(s), SM context ID, AMF ID, request type, N1 SM container (including PDU session establishment request), user location information, etc.

[0207] 4. SMF can perform subscription retrieval and / or subscription for updates.

[0208] If the session management subscription data for the corresponding SUPI, DNN, and S-NSSAI of the HPLMN is not available, the SMF retrieves the session management subscription data using Nudm_SDM_Get(SUPI, session management subscription data, selected DNN, S-NSSAI of the HPLMN, serving PLMN ID, [NID]). The SMF subscribes to be notified when this subscription data is modified and applies for the subscription using Nudm_SDM_Subscribe(SUPI, session management subscription data, selected DNN, S-NSSAI of the HPLMN, serving PLMN ID, [NID]).

[0209] UDM can obtain subscription information from UDR based on Nudr_DM_Query (including SUPI, subscription data, session management subscription data, selected DNN, HPLMN's S-NSSAI, serving PLMN ID, and [NID]). UDM can subscribe to notifications for the same data using Nudr_DM_subscribe.

[0210] 5. Based on the request received in step 3, SMF can send an Nsmf_PDUSession_CreateSMContext response (containing Cause, SM Context ID or N1 SM container (PDU Session Reject (Cause))) or an Nsmf_PDUSession_UpdateSMContext response to AMF.

[0211] 6. Optional secondary authentication / authorization is performed.

[0212] 7a. If dynamic PCC is to be used for the PDU Session, the SMF performs PCF selection. If the Request Type indicates "Existing PDU Session" or "Existing Emergency PDU Session", the SMF shall use the PCF already selected for the PDU Session.

[0213] 7a. When dynamic PCC is used for a PDU session, the SMF performs PCF selection. If the request type is indicated as "Existing PDU Session" or "Existing Emergency PDU Session," the SMF must use the PCF already selected for the PDU session.

[0214] Otherwise, SMF can apply local policies.

[0215] 7b. The SMF can perform the SM Policy Association Establishment Procedure to establish an SM Policy Association with the PCF and obtain the basic PCC rules for the PDU session. The SMF includes the 3GPP Data Off state if received in Step 1. If an alternate S-NSSAI is received in Step 3, the SMF includes the alternate S-NSSAI.

[0216] 8. SMF selects one or more UPFs as needed.

[0217] 9. SMF may provide information about the satisfied policy control request trigger conditions by performing an SMF-initiated SM policy association modification procedure.

[0218] 10. If the request type indicates "Initial Request", SMF initiates the N4 session setup procedure with the selected UPF, otherwise it initiates the N4 session modification procedure with the selected UPF:

[0219] 10a. SMF sends an N4 session setup / modification request to UPF and provides packet detection, enforcement and reporting rules to be installed in UPF for this PDU session.

[0220] 10b. UPF acknowledges this by sending an N4 Session Establishment / Modification Response.

[0221] 11. SMF can send Namf_Communication_N1N2MessageTransfer to AMF.

[0222] 12. AMF may send an N2 PDU Session Request (N2 SM information, NAS message (PDU Session ID, N1 SM container (PDU Session Setup Accept)), [CN Supported RAN Parameter Tuning]) to (R)AN. If N2 SM information is not included in step 11, an N2 Downlink NAS Transmit message is used instead.

[0223] 13. (R)AN may perform specific signaling exchanges with the UE related to information received from the SMF.

[0224] 14. (R)AN may send an N2 PDU session response message to AMF.

[0225] 15. AMF can send Nsmf_PDUSession_UpdateSMContext request (SM Context ID, N2 SM information, Request Type) to SMF.

[0226] 16a. SMF initiates the UPF and N4 session modification procedure. SMF provides tunnel information and corresponding forwarding rules to UPF.

[0227] 16b. UPF provides an N4 session modification response to SMF.

[0228] 16c. If the request type in step 3 does not indicate "Emergency Request" or "Existing Emergency PDU Session" and the SMF has not yet registered for this PDU Session, the SMF registers with the UDM using Nudm_UECM_Registration(SUPI, DNN, S-NSSAI of HPLMN, PDU Session ID, SMF Identity, Serving Node PLMN ID, [NID]) for the given PDU Session.

[0229] 17. SMF can send an Nsmf_PDUSession_UpdateSMContext response message (including Cause) to AMF.

[0230] 18. [Conditional Action] SMF sends the Nsmf_PDUSession_SMContextStatusNotify (Release) message to AMF.

[0231] 19. From SMF to UE: For PDU session type IPv6 or IPv4v6, SMF generates an IPv6 router advertisement and sends it to the UE.

[0232] 20. When the 5GS Bridge / Router Information Available trigger is triggered, SMF can start modifying SM policy associations.

[0233] 21. If the PDU session establishment fails after step 4, the SMF can:

[0234] The SMF unsubscribes from modifications to the session management subscription data for that (SUPI, DNN, S-NSSAI of HPLMN) using Nudr_SDM_Unsubscribe(SUPI, session management subscription data, DNN, S-NSSAI of HPLMN) when the SMF no longer processes the PDU session of the UE for that (DNN, S-NSSAI of HPLMN). The UDM can unsubscribe from modification notifications of a UDR via Nudr_DM_Unsubscribe(SUPI, subscription data, session management subscription data, S-NSSAI of HPLMN, DNN).

[0235] Below, an example of the Npcf_SMPolicyControl_Create service operation is described.

[0236] Service operation name: Npcf_SMPolicyControl_Create.

[0237] Description: An NF service consumer can request the creation of an SM policy association and provide the relevant parameters for the PDU session to the PCF.

[0238] Input, required: SUPI (or PEI for emergency PDU sessions without SUPI), PDU session ID, DNN, S-NSSAI, and RAT type.

[0239] Input, optional: Information provided by the SMF. According to the examples disclosed in this specification, an alternative S-NSSAI may be included. For reference, for alternative S-NSSAI, see TS 23.501 V18.0.0, clause 5.15.19.

[0240] Output, Required: SM Policy Association ID

[0241] Input, optional: Policy information for PDU sessions and policy control request triggers in SM policy associations.

[0242] For specific usage of this service task, reference can be made to 3GPP TS 23.502 V18.0.0 section 4.16.4.

[0243] The example below illustrates how to support AF requests without advertising an alternate S-NSSAI.

[0244] According to the previous technology, a method for supporting AF requests without announcing an alternate S-NSSAI has not been discussed. When the AF provides direct input to the PCF, the AF searches for the PCF through the BSF. Since the AF does not know the alternate S-NSSAI, it always uses the original S-NSSAI and the DNN to find the PCF. Therefore, even if an alternate S-NSSAI is used, the binding information in the BSF must be the S-NSSAI.

[0245] Currently, the alternate S-NSSAI is reported to the PCF only when the existing PDU session is maintained. When a new PDU session is established using the alternate S-NSSAI, the SMF reports the S-NSSAI as the value of the alternate S-NSSAI. Therefore, the PCF cannot determine whether a slice has been replaced.

[0246] As an example below, when establishing a new PDU session using the alternate S-NSSAI, the SMF can report both the S-NSSAI and the alternate S-NSSAI to the PCF. The PCF uses the S-NSSAI to register binding information.

[0247] According to the example below, AF requests can be processed effectively.

[0248] For example, PCF can perform event reporting.

[0249] An AF can subscribe to / unsubscribe from PCF event notifications for PDU sessions to which the AF session is connected. An AF can subscribe / unsubscribe directly to a PCF or indirectly via NEF or TSCTSF.

[0250] A PCF for a UE can subscribe / unsubscribe to PCF event notifications for the UE's PDU sessions. Other NFs can subscribe / unsubscribe to PCF event notifications for PDU sessions or UEs.

[0251] Examples of events that AF and other NFs can join are shown in Table 4.

[0252] Event Description Availability of NFRx PDU Sessions for Subscription Reporting Availability of N5 per PDU Session Availability of Bulk Subscription Availability of N43 based on SUPI, DNN, and S-NSSAI Availability of N5 per UE Availability of N24 per UE Network Slice Replacement PCF reports a change event between an S-NSSAI and an alternate S-NSSAI. PCF provides the alternate S-NSSAI when a PDU session transitions from an S-NSSAI to the alternate S-NSSAI. PCF also reports this event when a new PDU session is established using the alternate S-NSSAI. PCFNoYesNoYesNoNo

[0253] Table 4 shows examples of events related to reporting by PCF. Availability for N5 per PDU Session may mean that information reporting events for PDU sessions are available between PCF and AF.

[0254] Note that Table 3 only includes events related to network slice replacement (or replacement) relevant to the disclosure of this specification, but this is for illustrative purposes only. For events not included in Table 3, 3GPP TS 23.503 V18.0.0 Table 6.1.3.18-1 may be applied.

[0255] The Network Slice Replacement Report Request triggers the PCF to report to the AF when it receives a notification of a network slice replacement from the SMF. The PCF reports to the AF that a network slice replacement has occurred and reports the replacement S-NSSAI to the AF if provided by the SMF. Note that the AF can directly request the event from the PCF and receive the report. Alternatively, the AF can request the event from the PCF through the NEF and receive the PCF report through the NEF. Whether or not the NEF is used may vary depending on whether the operator allows direct interworking between the AF and the 5GC. Upon receiving a subscription for this event, the PCF sets the corresponding Policy Control Request Trigger in the SMF, if not already subscribed.

[0256] Network slice replacement for PDU Session is as follows:

[0257] Network slice replacement is specified in TS 23.501 V18.0.0 section 5.15.19.

[0258] PCF can set up network slice replacement trigger events in SMF.

[0259] For an existing PDU session that is migrated from an S-NSSAI to a replacement S-NSSAI or from a replacement S-NSSAI to an S-NSSAI, the SMF may determine that the existing PDU session and its existing SM policy associations can be maintained (e.g., if the SMF determines that the same PCF can be used for the replacement S-NSSAI). In this case, the SMF updates the S-NSSAI of the PDU session by including the replacement S-NSSAI in the SM policy association modification request for the PCF.

[0260] For a new PDU session, if the SMF receives an alternate S-NSSAI from the AMF, the SMF must provide both the S-NSSAI and the alternate S-NSSAI during the SM policy association establishment procedure.

[0261] The PCF requests subscription information related to the alternate S-NSSAI from the UDR. If the PCF is configured to subscribe to AF request notifications from the UDR, the PCF must use the alternate S-NSSAI if it is used for a PDU session (i.e., it must not use the alternate S-NSSAI). The PCF can then make policy decisions based on the received information and generate PCC rules (if a new PDU session is established) or provide updated PCC rules (if an existing PDU session is maintained) to the SMF. The PCF must use the S-NSSAI when registering or updating binding information with the BSF.

[0262] Additionally, instead of always transmitting both S-NSSAI and Alternative S-NSSAI to the PCF, the SMF can behave as follows. For example, the SMF can be configured to transmit both S-NSSAI and Alternative S-NSSAI only for PDU sessions that use a specific DNN and / or S-NSSAI (original S-NSSAI or replaced S-NSSAI). For example, the SMF can be configured to transmit both S-NSSAI and Alternative S-NSSAI only for specific DNNs and / or S-NSSAIs that must support AF requests. If the SMF is not configured to transmit both S-NSSAI and Alternative S-NSSAI, the SMF can transmit the Alternative S-NSSAI value instead of the S-NSSAI value in the sliceInfo when transmitting the sliceInfo to the PCF.

[0263] Below, a method for supporting a case where AF triggers slice replacement is described. According to the disclosure of the present specification, AF triggered slice replacement can be supported.

[0264] In the prior art, the AF does not know whether the Alternative S-NSSAI is used. For example, if a specific application is serviced through a DNN and S-NSSAI, the AF can request QoS for the DNN and S-NSSAI. At this time, the AF can include the DNN and S-NSSAI along with information about the requested QoS when using the Nnef_AFsessionWithQoS_Create service. Even if 5GS changes the S-NSSAI of the PDU Session used by the application to the Alternative S-NSSAI for some reason, the AF always requests QoS using the S-NSSAI (i.e., the S-NSSAI before the change) because it does not know the Alternative S-NSSAI.

[0265] In addition to QoS requests, S-NSSAI is used as an input parameter in various services provided by NEF. By default, AF always uses S-NSSAI as an input parameter because it is unaware of whether slice replacement is occurring. Therefore, AF requests can be processed without problems without updating the BSF with alternative S-NSSAI information. While the following primarily focuses on QoS requests, it can be extended to other AF requests as well.

[0266] Meanwhile, a method for performing slice replacement based on AF requests is being discussed. Unlike the conventional technique of performing slice replacement in 5GS due to internal reasons (e.g., slice congestion), a method is being discussed in which AF performs replacement for specific terminals as needed.

[0267] For example, a scenario can be supported where AF provides a service to a specific terminal based on a basic slice, and then AF temporarily changes the slice to provide a better service when the terminal pays a specific fee.

[0268] For example, AF can provide 5GC with S-NSSAI / Alternative S-NSSAI for direct replacement. In this case, AF may be aware of Alternative S-NSSAI information. Therefore, when requesting QoS, etc. from 5GC, AF can provide input based on Alternative S-NSSAI.

[0269] In this case, AF needs to provide Alternative S-NSSAI information to BSF. Alternatively, AF can provide requirement information for slice replacement (e.g., service requirements such as latency, error rate, data rate, high / low quality slice, URLLC / eMBB slice, etc.) to 5GC, and perform slice replacement by selecting Alternative S-NSSAI in the network.

[0270] For example, AF can provide various types of information to 5GC, such as information indicating the need for high throughput / rate, information indicating the need for high reliability, information indicating the need for low latency, information indicating the need for XR services, information indicating the need for specific capabilities / features, etc. Based on the provided information, the network (e.g. PCF) can determine which Alternative S-NSSAI is required and perform slice replacement based on the determined alternative S-NSSAI.

[0271] Additionally, when the AF makes a QoS request, it may request for a specific DNN or S-NSSAI. In this case, if the AF is unaware of slice replacement, it may not be able to distinguish whether the QoS request for the DNN or S-NSSAI sent by the AF is for a slice that has undergone slice replacement or a request for an S-NSSAI that has not undergone slice replacement. To support the above scenario, when the AF makes a QoS request, the AF can send information that can distinguish which slice the request is for.

[0272] For example, the AF may send a QoS request containing the Alternative S-NSSAI, requirements information for slice modification (e.g., high throughput / rate required, high reliability required, low latency required, XR service required, specific capability / feature required, etc.). The BSF shall also store and manage both the S-NSSAI and the Alternative S-NSSAI.

[0273] Meanwhile, according to the prior art, even if a slice replacement occurs, the BSF is not affected. Therefore, in some cases, the PCF may update the Alternative S-NSSAI to the BSF, and in other cases, it may not update the Alternative S-NSSAI.

[0274] For example, if a slice replacement occurs due to an AF request, the PCF can update the Alternative S-NSSAI to the BSF. Otherwise (e.g., if a slice replacement occurs due to a 5GC and not based on an AF request), the PCF may not update the Alternative S-NSSAI to the BSF. To this end, when the AMF performs a slice replacement due to an AF request, the AMF can transmit information on whether the slice replacement occurred due to an AF request along with the Alternative S-NSSAI to the SMF. Based on the information transmitted by the AMF, the SMF can inform the PCF whether the slice replacement occurred due to an AF request. Based on this, the PCF can update the BSF only if the slice replacement occurred due to an AF request.

[0275] Hereinafter, with reference to FIGS. 6A and 6B, examples of procedures based on various examples of the disclosure of the present specification are described.

[0276] 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.

[0277] FIGS. 6A and 6B illustrate an example of a procedure related to slice replacement according to one embodiment of the disclosure of the present specification.

[0278] Figures 6a and 6b are examples of a procedure that supports AF triggered slice replacement.

[0279] 1. The UE performs the Registration procedure. During this process, the AMF creates a PCF and AM Policy Association. The PCF registers itself with the BSF as the serving PCF for the UE. The PCF registers with the BSF by performing the Nbsf_Management_Register service. The PCF can inform the BSF of the UE's SUPI information and PCF information (e.g., PCF address, PCF instance ID, PCF Set ID, etc.). Based on the received information, the BSF stores the information about the UE and the PCF.

[0280] 2. The terminal performs the PDU session establishment procedure. The terminal creates a PDU session. Based on the URSP rule, the terminal transmits information such as the DNN and S-NSSAI to the network and creates a PDU session. The terminal receives services through the PDU session.

[0281] 3. AF may decide to change the slice that the terminal is using.

[0282] 4. AF can send Nnef_AMPolicyAuthroization Request to NEF. Nnef_AMPolicyAuthroization Request can include terminal information (e.g., SUPI, GPSI), information for slice replacement (e.g., S-NSSAI, Alternative S-NSSAI, requirement information for slice change).

[0283] 5. The NEF sends a management subscribe message to the BSF. The BSF sends a management notification message to the NEF.

[0284] To find the terminal's serving PCF, the NEF provides the terminal's SUPI to the Binding Support Function (BSF). Based on the information stored in step 1, the BSF can transmit the terminal's serving PCF information to the NEF.

[0285] 6. NEF can perform Npcf_AMPolicyAuthroization_Create for AM-PCF.

[0286] For example, the NEF can identify the serving PCF based on information received from the BSF. The NEF performs Npcf_AMPolicyAuthroization_Create with the serving PCF. At this time, the NEF can transmit the slice replacement information and terminal information received from the AF to the serving PCF. If the AF does not provide the Alternative S-NSSAI but provides the requirement information for slice replacement, the NEF may select the Alternative S-NSSAI.

[0287] 7. PCF may perform procedures to replace S-NSSAI with Alternative S-NSSAI based on AF request.

[0288] If AF sends a request for slice change without providing Alternative S-NSSAI information, PCF may determine Alternative S-NSSAI directly based on the request.

[0289] The AF may also transmit S-NSSAI information in step 4. Alternatively, S-NSSAI information used by each AF (by AF identifier) ​​may be configured in the NEF. Based on the information provided by the AF or information configured for each AF, the NEF can determine the S-NSSAI information. The NEF can then transmit the determined S-NSSAI information to the PCF. Alternatively, S-NSSAI information used by each AF may be configured in the PCF.

[0290] 8. The PCF can notify the AMF that it will replace the S-NSSAI with an Alternative S-NSSAI. To do this, the PCF sends the S-NSSAI and Alternative S-NSSAI mapping information to the AMF. During this process, the PCF sends the AMF information indicating that the slice replacement is due to an AF request. Alternatively, the PCF can send the AMF information including information that the Alternative S-NSSAI information needs to be updated in the BSF.

[0291] 9. PCF can send notification messages to AF via NEF.

[0292] For example, the PCF can notify the AF via the NEF that a slice replacement has been performed on the terminal. At this time, the PCF can notify the AF that the S-NSSAI has changed to an Alternative S-NSSAI. Based on the event subscription that the AF made in Steps 4 and 6 to report the results of the slice replacement report, the PCF can also report to the AF that the S-NSSAI has changed to an Alternative S-NSSAI.

[0293] Although Step 9 is depicted in the diagram as being performed before Step 10, this is merely an example. For example, Step 9 could be performed after Step 10 is performed, after the AMF notifies the PCF of a replacement event for the Alternative S-NSSAI.

[0294] In step 9, NEF can store information about UE, S-NSSAI, and Alternative S-NSSAI.

[0295] 10. AMF can perform a UE configuration update procedure. For example, AMF can send S-NSSAI and Alternative S-NSSAI mapping information to the UE to replace the UE's S-NSSAI with Alternative S-NSSAI.

[0296] 11. AMF may request SMF to replace S-NSSAI with Alternative S-NSSAI.

[0297] If the PDU session is released, steps 12 through 15 may be performed. If the PDU session is maintained, steps 12a through 14a may be performed.

[0298] 12. The SMF may determine that a new PDU Session needs to be created to replace the S-NSSAI of the current PDU Session. The SMF performs the PDU Session Release procedure. At this time, the SMF may notify the UE that a PDU Session based on the Alternative S-NSSAI should be created.

[0299] 13. The terminal can send a PDU session establishment request message.

[0300] For example, the terminal performs a procedure to create a PDU Session using Alternative S-NSSAI based on information provided by the SMF through the PDU Session Release Command. To this end, when the terminal transmits a PDU Session Establishment Request, it transmits a UL NAS Transport message that includes both S-NSSAI and Alternative S-NSSAI.

[0301] 14. Based on the information received in step 8, the AMF can determine that the slice replacement is due to an AF request. The AMF can notify the SMF of the slice replacement due to an AF request by forwarding the PDU Session Establishment Request transmitted by the terminal. Alternatively, the AMF can inform the BSF that the Alternative S-NSSAI needs to be updated.

[0302] 15. When creating a SM Policy Association with the PCF, the SMF notifies the PCF that the slice replacement is due to an AF request, along with the Alternative S-NSSAI information. Alternatively, the SMF notifies the BSF that the Alternative S-NSSAI needs to be updated.

[0303] If the PDU session is maintained, steps 12a to 14a may be performed.

[0304] 12a. The SMF may decide to maintain the current PDU Session in order to replace the S-NSSAI of the current PDU Session. The SMF may transmit a PDU Session Modification Command message to the terminal while performing the PDU Session Modification procedure. At this time, the SMF notifies the terminal that the S-NSSAI of the PDU Session has been changed to the Alternative S-NSSAI.

[0305] 13a. The terminal can transmit PDU Session Modification Complete to SMF.

[0306] 14a. When performing SM Policy Association Modification with the PCF, the SMF can transmit Alternative S-NSSAI information and information indicating that the slice replacement is due to an AF request to the PCF. The SMF can also inform the BSF that the Alternative S-NSSAI needs to be updated.

[0307] 16. Based on the information transmitted by the SMF, the PCF transmits S-NSSAI, Alternative S-NSSAI, PDU Session information (e.g., UE IP address, DNN, etc.), PCF information, and information indicating that replacement has been made by AF request to the BSF, and the BSF can store this.

[0308] 17. The AF can execute the Nnef_AFsessionWithQoS_Create service to request QoS. At this time, the AF provides information such as the IP address, DNN, and S-NSSAI according to the conventional procedure. In addition, the AF can also send the Nnef_AFsessionWithQoS_Create request message that includes not only the S-NSSAI but also Alternative S-NSSAI information or information on requirements for slice modification.

[0309] 18. The NEF performs PCF discovery with the BSF using the IP address, S-NSSAI, and Alternative S-NSSAI to find the serving PCF. The NEF can perform discovery as follows.

[0310] 19. NEF executes the Npcf_PolicyAuthorization_Create service to forward the AF request to the PCF found in step 18. Based on this, the PCF can update the PCC rule to satisfy the QoS.

[0311] 20. NEF sends a response to AF.

[0312] Another AF (e.g., legacy AF) that has not performed slice replacement can perform QoS requests for the same PDU Session. In this case, the AF can only provide legacy information (e.g., DNN, S-NSSAI, IP address information) without the Alternative S-NSSAI information. In this case, the NEF performs BSF discovery for the PCF without the Alternative S-NSSAI information. The BSF performs PCF discovery based on the DNN, S-NSSAI, and IP address information without using the Alternative S-NSSAI.

[0313] An AF request may be for a group of UEs, and slice replacement may occur for only some of them. In this case, the AF may not perform all AF requests at once, but may perform AF requests separately for the UEs that have experienced slice replacement and the UEs that have not. To support this, the PCF managing the session where slice replacement has occurred must perform subscriptions as follows. For example, this PCF must perform subscriptions for DNN + S-NSSAI as well as DNN + Alternative S-NSSAI through UDR. Once the PCF performs these subscriptions, it can receive AF requests from the UDR.

[0314] Alternatively, when AF requests QoS for a group of UEs, it can only adjust QoS for terminals / sessions that have not experienced slice replacement. If AF wants to request QoS for terminals / sessions that have experienced slice replacement, AF can always perform per-UE / per-session QoS requests.

[0315] In addition, when AF requests slice replacement, 5GC may need to perform slice replacement again for reasons such as congestion for a PDU Session using Alternative S-NSSAI. For example, slice-X may be replaced by slice-Y by AF. Later, congestion may occur for slice-Y, causing slice-Y to be replaced by slice-Z. In this case, AF's request (e.g., QoS) is performed for Alternative S-NSSAI (slice-Y). Therefore, when NEF searches for a serving PCF through BSF, BSF cannot find a PCF that matches S-NSSAI (slice-X) and Alternative S-NSSAI (slice-Y). To solve this problem, BSF may perform the following actions when searching for S-NSSAI and Alternative S-NSSAI based on binding information. For example, if the replacement in the binding information is performed by 5GC, and other parameters (e.g., DNN, S-NSSAI, IP address, etc.) match even if the Alternative S-NSSAI does not match, the BSF can report the corresponding PCF information to the serving PCF. This behavior is possible because the BSF stores whether the slice replacement was initiated by an AF request.

[0316] As above, the PCF may not provide information to the AMF about whether slice replacement is initiated by AF. The PCF may always register an Alternative S-NSSAI when registering binding information for a PDU Session with the BSF. This way, if 5GC performs slice replacement by AF request, the NEF may have trouble finding the serving PCF from the BSF when 5GC performs replacement again, but the impact on the network node can be reduced. Even in this case, the BSF may still notify the serving PCF of the matching PCF information based on other parameters, even if the Alternative S-NSSAI does not match.

[0317] The various examples described above in this specification may be combined. Below, examples to which the disclosure of this specification applies are described with reference to FIG. 7.

[0318] Hereinafter, with reference to FIG. 7, an example of operations according to an embodiment of the disclosure of the present specification is described. The example of FIG. 7 may include operations based on various examples of the disclosure of the present specification.

[0319] 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.

[0320] FIG. 7 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0321] For reference, the procedure illustrated in FIG. 7 is merely an example, and the scope of the disclosure of this specification is not limited by the example in FIG. 7.

[0322] For example, with respect to the example of FIG. 7, the operations described in the examples of FIGS. 1 to 6B may also be applied. For example, even if operations, contents, etc. are not directly described in the example of FIG. 7, operations, contents, etc. described in various examples of the disclosure of this specification may be applied.

[0323] The operations illustrated in FIG. 7 are merely examples, and the scope of the disclosure of this specification is not limited to the operations illustrated in FIG. 7.

[0324] For reference, in the description below, the first PCF may mean SM-PCF, and the second PCF may mean AM-PCF.

[0325] In step (S701), AF can send a policy authentication request message to NEF.

[0326] For example, a policy authentication request message may be a message for slice replacement. The policy authentication request message may include information related to the UE and information related to slice replacement of the UE's PDU session.

[0327] For example, if the policy authentication request message does not include the alternative S-NSSAI, the AF may determine the alternative S-NSSAI based on requirements included in the information related to slice replacement.

[0328] In step (S702), the NEF may send a management subscribe message to the BSF. For example, the management subscribe message may include information related to the UE.

[0329] For example, the BSF can retrieve the first PCF based on information related to the UE.

[0330] In step (S703), NEF can receive a management notification message from BSF.

[0331] For example, the management notification message may contain information related to the first PCF serving the UE.

[0332] At step (S704), NEF can send a policy authentication message to PCF.

[0333] For example, the NEF may send a policy authentication message to the first PCF that includes information related to the UE and information related to slice replacement.

[0334] For example, the policy authentication message can be used by the first PCF to perform a procedure to replace the S-NSSAI of a PDU session based on a request from the AF.

[0335] For example, the NEF may receive a policy authentication notification message from the first PCF that includes information that a slice replacement has been completed.

[0336] For example, NEF can send a policy authentication notification message to AF.

[0337] For example, the first PCF may perform a slice replacement procedure at the request of the AF based on information related to the UE and information related to the slice replacement.

[0338] For example, the first PCF may send an update notification message to the AMF containing information to replace the S-NSSAI of the PDU session with an alternate S-NSSAI.

[0339] For example, the update notification message may further include information that the replacement with the replacement S-NSSAI is based on a request from the AF.

[0340] For example, the update notification message may further include mapping information between the S-NSSAI and the alternative S-NSSAI.

[0341] Based on the slice replacement, the PDU session may be maintained or released. For example, a second PCF (e.g., SM-PCF) serving the UE's PDU session may receive a message from the SMF related to the SM policy association, which includes replacement S-NSSAI information and information that the slice replacement is based on the AF's request.

[0342] Although not shown in the example of FIG. 7, the AMF may send a message to the UE related to a UE configuration update that includes mapping information.

[0343] For example, the AMF may send the SMF a context update message containing information requesting the SMF to replace the S-NSSAI of the PDU session with an alternate S-NSSAI.

[0344] For example, AMF may receive a message from SMF regarding PDU session release that includes information requesting creation of a PDU session based on an alternate S-NSSAI.

[0345] For example, AMF may send a message to the UE regarding PDU session release.

[0346] For example, the AMF may receive a PDU session establishment request message, S-NSSAI information, and alternative S-NSSAI information from the UE.

[0347] For example, the AMF may send an information and PDU session establishment request message to the SMF indicating a slice replacement based on a request from the AF, based on information received to replace with an alternate S-NSSAI.

[0348] In step (S705), AF can send a QoS creation message to NEF.

[0349] For example, the NEF may receive a QoS creation message containing an S-NSSAI and an alternate S-NSSAI from the AF.

[0350] At step (S706), the NEF may send a management search message to the BSF.

[0351] For example, a management search message may contain both an S-NSSAI and an alternate S-NSSAI.

[0352] Based on the management search message, the BSF can search for a second PCF that matches the S-NSSAI and the alternate S-NSSAI. The second PCF may be an SM-PCF that serves the PDU session of the UE. For example, the NEF can receive information related to the second PCF that satisfies both the S-NSSAI and the alternate S-NSSAI and serves the PDU session of the UE from the BSF.

[0353] For example, the NEF may send a policy authentication message for QoS update to the second PCF. The policy authentication message may include an S-NSSAI and an alternate S-NSSAI.

[0354] This specification may have various effects.

[0355] For example, even if slice replacement is performed at the request of AF, the AF's QoS request can be processed. Unlike the prior art, information related to slice replacement can also be provided to the BSF.

[0356] The effects that can be achieved through the 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.

[0357] For reference, the operation of the terminal (e.g., UE, terminal) described in this specification can be implemented by the devices of FIGS. 1 to 3 described above. For example, the terminal can be the first device (100) or the second device (200) of FIG. 2. For example, the operation of the terminal described in this specification can be processed by one or more processors (102 or 202). The operation of the terminal described in this specification can be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). The one or more processors (102 or 202) control one or more memories (104 or 204) and one or more transceivers (105 or 206), and execute the instructions / programs stored in one or more memories (104 or 204) to perform the operation of the terminal (e.g., UE) described in the disclosure of this specification.

[0358] Additionally, the commands for performing the operations of the terminal described in the disclosure of this specification may be stored in a non-volatile computer-readable storage medium. The storage medium may be included in one or more memories (104 or 204). In addition, the commands recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the terminal described in the disclosure of this specification.

[0359] For reference, the operations of a network node (e.g., AMF, AM-PCF, SM-PCF, BSF, SMF, UPF, UDM, H-PCF, V-PCF, NEF, AF, UDR, UDM, DN, etc.) or a base station (e.g., NG-RAN, gNB, RAN, (R)AN, etc.) described in this specification may be implemented by the devices of FIGS. 1 to 3 described below. For example, the network node or the base station may be the first device (100) or the second device (200) of FIG. 2. For example, the operations of the network node or the base station described in this specification may be processed by one or more processors (102 or 202). The operations of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). One or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (106 or 206), and execute instructions / programs stored in one or more memories (104 or 204) to perform operations of a network node or base station as described in the disclosure of this specification.

[0360] Additionally, the instructions for performing the operations of the network node or base station described in the disclosure of this specification may be stored in a non-volatile (or non-transitory) computer-readable storage medium having the instructions recorded thereon. The storage medium may be included in one or more memories (104 or 204). In addition, the instructions recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the network node or base station described in the disclosure of this specification.

[0361] Although the preferred embodiments have been described above by way of example, the disclosure of this specification is not limited to these specific embodiments, and may be modified, changed, or improved in various forms within the scope of the spirit and claims of this specification.

[0362] In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks. However, the order of the steps described is not limited, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the invention.

[0363] 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. In the method of performing communication by Network Exposure Function (NEF), A step of receiving a policy authorization request message for slice replacement from an Application Function (AF), The policy authentication request message for the above slice replacement includes information related to the User Equipment (UE) and information related to the slice replacement of the Protocol Data Unit (PDU) session of the UE; A step of transmitting a management subscribe message including information related to the UE to the BSF; A step of receiving a management notification message including information related to a first PCF serving the UE from the BSF; A step of transmitting a policy authentication message including information related to the UE and information related to the slice replacement to a first PCF serving the UE; A step of receiving a Quality of Service (QoS) generation message including Single Network Slice Selection Assistance Information (S-NSSAI) and alternative S-NSSAI from the AF; and A step of transmitting a management discovery message including both the S-NSSAI and the alternative S-NSSAI to the BSF; A step of receiving information related to a second PCF serving the PDU session of the UE from the BSF, the second PCF satisfying both the S-NSSAI and the alternative S-NSSAI; Including a step of transmitting a policy authentication message for QoS update to the second PCF, A method characterized in that the above policy authentication message includes the S-NSSAI and the alternative S-NSSAI.

2. In paragraph 1, A method characterized in that the above management search message is used by the BSF to search for the second PCF matching the S-NSSAI and the alternative S-NSSAI.

3. In paragraph 1 or 2, A method characterized in that the above policy authentication message is used by the PCF serving the UE to perform a procedure for replacing the S-NSSAI of the PDU session based on a request from the AF.

4. In any one of paragraphs 1 to 3, A step of receiving a policy authentication notification message including information that the slice replacement has been completed from a PCF serving the UE; and A method further comprising the step of transmitting the above policy authentication notification message to the AF.

5. In any one of paragraphs 1 to 4, A method characterized in that the above management subscription message is used by the BSF to search for a serving PCF of the UE based on information related to the UE.

6. In any one of paragraphs 1 to 4, A method further comprising the step of determining the alternative S-NSSAI based on requirements included in information related to the slice replacement, if the policy authentication request message does not include the alternative S-NSSAI.

7. In the Network Exposure Function (NEF) that performs communication, the NEF: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; An operation performed based on the above command being executed by the one or more processors is a NEF method according to any one of claims 1 to 6.

8. In the method of performing communication by the Policy Control Function (PCF), A step of receiving a message related to Session Management (SM) policy association from the Session Management Function (SMF), The message related to the above SM policy association includes information that the replacement S-NSSAI information and slice replacement related to the Protocol Data Unit (PDU) session of the User Equipment (UE) is based on a request from the Application Function (AF); and A method comprising the step of registering both the S-NSSAI and the Alternative S-NSSAI with the BSF based on information that the above alternative S-NSSAI information and slice replacement are based on a request from the AF.

9. In the Policy Control Function (PCF) that performs communication, the PCF: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; The operation performed based on the above command being executed by the one or more processors is a PCF method according to claim 8.

10. In the method of Access and Mobility Management Function (AMF) performing communication, A step of receiving an update notification message from the PCF including information to replace the S-NSSAI of the PDU session of the UE with a replacement S-NSSAI, The above update notification message includes mapping information between the S-NSSAI and the alternative S-NSSAI; A step of transmitting a message related to a UE configuration update including the above mapping information to the UE; and A method comprising the step of transmitting a context update message to an SMF including information requesting that the S-NSSAI of the PDU session be replaced with the alternative S-NSSAI.

11. In paragraph 10, A step of receiving a message related to PDU session release from the SMF, the message including information requesting creation of a PDU session based on the above alternative S-NSSAI; and A method further comprising the step of transmitting a message related to releasing the PDU session to the UE.

12. In paragraph 10 or 11, A method further comprising the step of receiving a PDU session establishment request message, the S-NSSAI information, and the alternative S-NSSAI information from the UE.

13. In any one of paragraphs 10 to 12, A method further comprising the step of transmitting, to the SMF, information indicating that the slice is replaced based on a request from an Application Function (AF) and the PDU session establishment request message based on the information received to replace with the alternative S-NSSAI.

14. In the Access and Mobility Management Function (AMF) that performs communication, the AMF: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; An operation performed based on the above command being executed by the one or more processors is an AMF method according to any one of claims 10 to 13.

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