Method and apparatus for updating terminal policy for continuity of network slicing service in wireless communication system

Abstract

According to an embodiment of the present disclosure, the present disclosure relates to a method and apparatus for efficiently updating a terminal policy for continuity of a network slicing service in a wireless communication system, and an AMF method in a wireless communication system supporting network slicing, comprising the steps of: AMF: receiving a registration request message from a terminal; selecting a first PCF supporting remapping of a network slice associated with the terminal; sending a first policy control request message to a first PCF, wherein the first policy control request message comprises information indicating whether the first PCF in the AMF supports network slice remapping; and receiving a first policy control response message including first trigger information related to network slice remapping from the first PCF in response to the transmission of the first policy control request message, in which at least one first network slice requiring network slice remapping occurs in the AMF, the first policy control response message including the first trigger information related to the network slice remapping; the first trigger information instructs the AMF to send information about at least one first network slice to the first PCF.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for supporting continuity of network slicing services in a wireless communication system. Background Art

[0002] 5G mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called millimeter waves including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called super 5G system) in terahertz frequency bands (e.g., 95 GHz to 3 THz frequency bands) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency of one tenth of 5G.

[0003] In the initial stage of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (URLLC) and massive machine type communication (mMTC), there is ongoing standardization on beamforming and massive MIMO for mitigating radio wave path loss in millimeter waves and increasing radio wave transmission distance, parameter sets (e.g., operating multiple subcarrier spacings) and dynamic operation of time slot formats for efficient utilization of millimeter wave resources, initial access technology for supporting multi-beam transmission and broadband, definition and operation of BWP (bandwidth part), new channel coding methods such as LDPC (low-density parity check) codes for large-scale data transmission and polar codes for highly reliable transmission of control information, L2 preprocessing, and network slicing for providing dedicated networks customized for specific services.

[0004] Currently, in view of the services that 5G mobile communication technology is to support, there are ongoing discussions on improvements and performance enhancements to initial 5G mobile communication technology, and there is already physical layer standardization on technologies such as V2X for assisting driving determination of autonomous vehicles based on information about the location and status of the vehicle sent by the vehicle and for enhancing user convenience, NR-U (New Radio Unlicensed) for system operation designed to comply with various regulatory requirements in unlicensed bands, NR UE power saving, non-terrestrial network (NTN) as UE-satellite direct communication for ensuring coverage in areas where communication with terrestrial networks is not possible, and positioning. Currently, there are ongoing discussions on improvements and performance enhancements of initial 5G mobile communication technologies in view of the services that 5G mobile communication technologies are to support, and there is already physical layer standardization on technologies such as: V2X for assisting driving decisions of autonomous vehicles based on information about the position and status of a vehicle transmitted by the vehicle and for enhancing user convenience, NR-U (Unlicensed New Radio) for system operation that is intended to comply with various regulatory-related requirements within unlicensed frequency bands, NR UE energy saving, non-terrestrial networks (NTNs) as UE-satellite direct communication for securing coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, in the field of radio interface architecture / protocol, there is already ongoing standardization on technologies such as the Industrial Internet of Things (IIoT) that supports new services through interconnection and convergence with other industries, IAB (Integrated Access and Backhaul) that provides nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (two-step RACH for NR) for simplifying the random access procedure. Standardization is also ongoing in the field of system architecture / services on a 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] If such a 5G mobile communication system is commercialized, the already exponentially growing number of connected devices will be connected to the communication network, and it is accordingly expected that enhanced functions and performance of the 5G mobile communication system and integrated operation of the connected devices will be necessary. To this end, new research is arranged involving extended reality (XR) for effectively supporting AR, VR, etc. (XR = AR + VR + MR), 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0007] In addition, such development of 5G mobile communication systems will serve as the basis for not only developing new waveforms for ensuring terahertz band coverage for 6G mobile communication technology, full-dimensional MIMO (FD-MIMO), multi-antenna transmission technologies such as array antennas and massive antennas, metamaterial-based lenses and antennas for improving terahertz band signal coverage, high-dimensional spatial multiplexing technology using OAM (orbital angular momentum), and RIS (reconfigurable smart surface), but also developing full-duplex technology for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technology for achieving system optimization and internalizing end-to-end AI support functions by utilizing satellites and AI (artificial intelligence) from the design stage, and next-generation distributed computing technology for implementing services at a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources. Summary of the invention

[0008] Technical issues

[0009] The present disclosure provides a method and apparatus for effectively updating a user equipment (UE) policy for continuity of network slice services in a wireless communication system.

[0010] In addition, the present disclosure provides a method and device for network slice remapping in a wireless communication system.

[0011] In addition, the present disclosure provides a method and device for network slice remapping during UE registration in a wireless communication system.

[0012] In addition, the present disclosure provides a method and apparatus for providing PCR triggering based on an AM policy or a UE policy in a wireless communication system.

[0013] In addition, the present disclosure provides a method and apparatus for determining / selecting a new network slice for network slice remapping in a wireless communication system.

[0014] Technical Solution

[0015] According to an embodiment of the present disclosure, a method performed by an AMF in a wireless communication system supporting network slicing may include: an operation of receiving a registration request message from a user equipment (UE) by the AMF, an operation of selecting a first policy control function (PCF) that supports network slice remapping related to the UE by the AMF, an operation of sending a first policy control request message by the AMF to the first PCF, the first policy control request message including information indicating to the first PCF whether the AMF supports network slice remapping, and an operation of receiving a first policy control response message from the first PCF by the AMF in response to the sending of the first policy control request message, the first policy control response message including first trigger information related to network slice remapping, and the first trigger information indicating that in a case where at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

[0016] In addition, according to an embodiment of the present disclosure, the AMF in a wireless communication system supporting network slicing may include a transceiver and a processor, wherein the processor is configured to: receive a registration request message from a user equipment (UE) via the transceiver, select a first policy control function (PCF) that supports network slice remapping related to the UE, send a first policy control request message to the first PCF via the transceiver, the first policy control request message includes information indicating to the first PCF whether the AMF supports network slice remapping, and in response to the sending of the first policy control request message, receive a first policy control response message from the first PCF via the transceiver, the first policy control response message includes first trigger information related to network slice remapping, and the first trigger information indicates that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

[0017] In addition, according to an embodiment of the present disclosure, the method performed by the first PCF in a wireless communication system supporting network slicing may include: an operation in which the first PCF supporting network slice remapping receives a first policy control request message from an AMF, the first policy control request message including information indicating whether an access and mobility management function (AMF) supports network slice remapping, the AMF receives a registration request message from a user equipment (UE), and an operation in which the first PCF sends a first policy control response message to the AMF in response to the reception of the first policy control request message, the first policy control response message including first trigger information related to network slice remapping, and the first trigger information indicates that in a case where at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

[0018] In addition, according to an embodiment of the present disclosure, the first PCF in a wireless communication system supporting network slicing may include a transceiver and a processor, the processor being configured to receive a first policy control request message from an AMF via the transceiver, the first policy control request message including information indicating whether an access and mobility management function (AMF) supports network slice remapping, the AMF receiving a registration request message from a user equipment (UE), and in response to receiving the first policy control request message, sending a first policy control response message to the AMF via the transceiver, the first policy control response message including first trigger information related to network slice remapping, the first trigger information indicating that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a diagram showing a network structure of a 5G system;

[0020] Figure 2 is a diagram illustrating a method for installing an AM policy-based PCR trigger to support slice remapping during UE registration according to an embodiment of the present disclosure;

[0021] Figure 3 is a diagram showing a method for determining a new network slice via an AM policy process when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure;

[0022] Figure 4 is a diagram illustrating a method for installing a UE policy-based PCR trigger to support slice remapping during UE registration according to an embodiment of the present disclosure;

[0023] Figure 5 is a diagram showing a method for determining a new network slice via a UE policy procedure when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure;

[0024] Figure 6 is a diagram illustrating a method of reporting a change of allowed NSSAI to an H-PCF via a UE policy procedure when the allowed NSSAI changes according to an embodiment of the present disclosure;

[0025] Figure 7 is a diagram showing a method for determining a new network slice by a (V-)PCF via a UE policy procedure when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure;

[0026] Figure 8is a diagram illustrating a method for installing a UE policy-based PCR trigger to support AMF-based slice remapping during UE registration according to an embodiment of the present disclosure; and

[0027] Fig. 9 is a diagram showing a configuration of a network entity in a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings. When describing the present disclosure below, a detailed description of known functions or configurations incorporated herein will be omitted when it is determined that the description may make the subject matter of the present disclosure unnecessarily unclear. The terms to be described below are terms defined in consideration of the functions in the present disclosure, and may differ depending on the user, the user's intention or custom. Therefore, the definition of terms should be based on the content in the entire specification.

[0029] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will be apparent. However, the present disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the attached claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements.

[0030] Herein, it will be understood that each block of the flowchart illustrations and combinations of blocks in the flowchart illustrations can be implemented by computer program instructions.

[0031] In addition, each box in the flow chart may represent a module, a fragment or a portion of a code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box may not occur in order. For example, two boxes shown in succession may actually be executed substantially simultaneously, or the boxes may sometimes be executed in reverse order, depending on the functions involved.

[0032] As used in the embodiments of the present disclosure, the term "unit" refers to a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and a "unit" can perform certain functions. However, a "unit" does not always have a meaning limited to software or hardware. A "unit" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, a "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" can be combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". In addition, elements and "units" can be implemented as one or more CPUs in a reproduction device or a secure multimedia card. In addition, a "unit" in an embodiment can include one or more processors.

[0033] As used herein, each of phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B or C" may include all possible combinations of items listed together in the corresponding one phrase. Terms such as "first", "second", "the first" and "the second" may be used to simply distinguish a corresponding element from another element and do not limit the elements in other respects (e.g., importance or order).

[0034] In the present disclosure, for the convenience of description, terms for identifying access nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are illustratively used. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to subjects with equivalent technical meanings may also be used.

[0035] In the following description of the present disclosure, for the sake of convenience of description, the terms and names defined in the 5GS and NR standards will be used, which are standards specified by the Third Generation Partnership Project (3GPP) group in the existing communication standards. However, the present disclosure is not limited to these terms and names, and can be applied to systems that comply with other standards in the same manner. The present disclosure can be applied to 3GPP 5GS / NR (fifth generation mobile communication standard).

[0036] In the following description, a base station is an entity that allocates resources to a terminal, and may be at least one of an eNode B, a Node B, a Base Station (BS), a Radio Access Network (RAN), an Access Network (AN), a RAN node, a wireless access unit, a base station controller, and a node on a network. A user equipment (UE) may be at least one of a terminal, a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function.

[0037] The 5G system supports a technology called Session and Service Continuity (SSC) mode, which supports session continuity to improve the quality of experience (QoE) of the UE or to support mission-critical services. SSC includes three modes, namely SSC modes 1, 2, and 3, and the 5G system can configure one of SSC modes 1, 2, and 3 for a protocol data unit (PDU) session. For example, in SSC mode 1, the user plane function (UPF) acting as the anchor of the PDU session is maintained until the user equipment (UE) releases the PDU session. In SSC mode 2, when an existing PDU session for the UE is released and a new PDU session is established in the 5G system, the UPF acting as the anchor in the existing PDU session can be changed to another UPF in the new PDU session. In SSC mode 3, the PDU session can be applied only to IP types, and when the UPF acting as the anchor is changed to a new UPF, a connection to the new UPF can be established before releasing the connection to the existing UPF. SSC mode 3 is a technology called connect before disconnection. When the network determines that the PDU session of SSC mode 3 being used by the UE needs to be released, the network can establish a new PDU session that can replace the existing PDU session and release the existing PDU session to support session continuity. Before releasing the existing PDU session, the UE moves the service flow being sent / received via the existing PDU session to the new PDU session to maintain session continuity.

[0038] In the 5G system, network slicing technology is a technology and structure for implementing various virtualized and independent logical networks in a single physical network. In order to meet the specified requirements of services / applications, network operators can configure virtual end-to-end networks called network slices, and can provide services. For example, a network operator can configure network slice A to provide mobile broadband services, can configure network slice B to provide vehicle communication services, and can configure network slice C to provide broadcast services. That is, as described above, in the 5G system, the corresponding service can be effectively provided to the UE via a network slice dedicated to the characteristics of each service.

[0039] The network slice is identified by an identifier called Single Network Slice Selection Assistance Information (S-NSSAI), and the network operator can use the network slice to provide services to the UE. In the present disclosure, "slice" is a term indicating a "network slice", and they are used interchangeably. In a network environment, a UE can access multiple network slices when receiving various services. The network operator can configure the network slices, and can allocate network resources suitable for the predetermined services for each network slice or each set of network slices. The network resources can be NFs or logical resources provided by NR, or radio resource allocations of base stations, etc.

[0040] During the network registration process, the UE sends identifier information associated with the network slice requested by the UE (e.g., requested S-NSSAI) to the access and mobility management function (AMF), and the AMF provides the UE with information associated with the network slices available to the UE (e.g., allowed NSSAI) taking into account the requested S-NSSAI, subscriber information, etc. Although the UE does not provide the AMF with information associated with the requested network slice, the AMF may provide the UE with the allowed NSSAI. In this case, the allowed NSSAI may include information associated with the default configured network slice (e.g., default configured NSSAI), and information associated with the network slice configured as the default in the subscribed network slice included in the UE subscriber information (e.g., default subscription S-NSSAI).

[0041] When any network slice cannot be included in the allowed NSSAI (e.g., when the default configured NSSAI and / or the default subscribed S-NSSAI does not exist or is unavailable), the AMF may send a network registration reject message to the UE along with a reason code indicating that the reason for the rejection is the absence of available slices.

[0042] In order to include a slice in the allowed NSSAI of the UE, an admission control (network slice admission control (NSAC)) process and an authentication (network slice specific authentication and authorization (NSSAA)) process may be performed on the corresponding slice in the 5G system. In the NSAC process, whether a predetermined network slice is allowed (e.g., whether the corresponding network slice is included in the allowed NSSAI) may be determined based on the number of UEs currently registered in the predetermined network slice and the maximum number of registered UEs allowed for the corresponding network slice. In the NSSAA process, an authentication process is performed based on credential information associated with the corresponding network slice of the UE using AAA-S, which is a server that performs authentication of the corresponding slice via an NSSAA function (NSSAAF). In this case, considering the authentication result, it may be determined whether the corresponding network slice is allowed (e.g., whether the corresponding network slice is included in the allowed NSSAI).

[0043] In order to perform data transmission or reception to a predetermined data network (DN) via an allowed network slice (allowed NSSAI), the UE may select one of the allowed network slices, may request a packet data unit (PDU) session to a predetermined data network name (DNN) from the corresponding network slice, and may perform data transmission or reception via the established PDU session. A PDU session may include multiple service flows, and a service flow may include two types of flows, namely, a guaranteed bit rate quality of service flow (GBR QoS flow) and a non-GBR QoS flow.

[0044] In a 5G system, due to congestion occurring in a predetermined network slice, or due to an operational (operation and management (OAM)) problem caused by a failure / equipment replacement / upgrade of a predetermined network slice, or when a service level agreement (SLA) related to a network slice proposed by a network operator to a third party is not met, a portion of a network slice that a UE is using by establishing a PDU session may become unavailable, or although it is available, it may experience performance degradation (hereinafter, such a network slice is referred to as a network slice that requires / requires remapping). In this case, in a 5G system, a method for moving an existing PDU session belonging to a corresponding network slice to another network slice (hereinafter, such a network slice is referred to as a remapped network slice) is required. In the present disclosure, the method is referred to as network slice remapping. In this case, a network slice that needs to be remapped and a remapped network slice may be determined for each UE, and it is considered important to ensure session continuity. In addition, in the present disclosure, when network slice remapping is performed, a rule indicating whether a network slice for each service needs to be used (e.g., a UE routing policy (URSP) rule in a UE policy) may be updated and then sent to the UE. The rule may be stored in the UE as configuration information. The UE routing selection policy (URSP) may include SSC mode selection policy, network slice selection policy, data network name (DNN) selection policy, non-seamless offload policy, access type preference (preference for 3GPP or non-3GPP), etc.

[0045] In the present disclosure, standards (e.g., TS 23.501, TS 23.502, TS 23.503, etc.) defined by 3GPP or the International Telecommunication Union (ITU) may be referred to as network technologies. Figure 1 The network entities in the network structure can be physical entities, software that performs various functions, or hardware coupled with software. The reference numerals N1, N2, N3, ..., Nxxx, etc. in the accompanying drawings are well-known interfaces between NFs in the 5G core network (5GC).

[0046] In the 3GPP system, the conceptual links connecting the network functions (NFs) in the 5G system are defined as reference points. Figure 1 An example of reference points in the 5G system architecture represented in is as follows.

[0047] -N1: Reference point between UE and AMF

[0048] -N2: Reference point between base station ((R)AN) and AMF

[0049] -N3: Reference point between base station ((R)AN) and UPF

[0050] -N4: Reference point between Session Management Function (SMF) and UPF

[0051] -N5: Reference point between PCF and Application Function (AF)

[0052] -N6: Reference point between UPF and data network (DN)

[0053] -N7: Reference point between SMF and Policy Control Function (PCF)

[0054] -N8: Reference point between User Data Management (UDM) and AMF

[0055] -N9: Reference point between two core UPFs

[0056] -N10: Reference point between UDM and SMF

[0057] -N11: Reference point between AMF and SMF

[0058] -N12: Reference point between AMF and Authentication Server Function (AUSF)

[0059] -N13: Reference point between UDM and AUSF

[0060] -N14: Reference point between two AMFs

[0061] -N15: Reference point between PCF and AMF in case of non-roaming scenario, and between PCF and AMF in visited network in case of roaming scenario

[0062] Figure 1 It is a diagram showing the network structure of a 5G system.

[0063] Figure 1The 5G system of the present invention may include a 5G core network (5GC), a base station 105, and a user equipment (UE) 100. The 5GC may include an AMF 110 that manages the mobility of the UE 100, an SMF 115 that manages sessions, a UPF 120 that connects to a data network (DN) 125 and performs data transmission, a network slice selection function (NSSF) 125 that selects a network slice to provide a service to the UE 100, an AUSF 130 that authenticates one or more network entities in the 5G system, a network exposure function (NEF) 140 that transmits events and supported capabilities occurring in the 5G system to the outside or receives the same events from the outside, a network repository function (NRF) 150 that manages registration information of NFs, a PCF 155 that provides a policy control function of a network operator, and a UDM 160 that provides a data management function such as subscriber data, policy control data, etc., and an AF 170 that provides application services may communicate with the 5GC. The AMF 110 may be an entity for managing access and mobility of the UE 100. For example, the AMF 120 may perform network functions such as registration, connection, reachability, mobility management, access identification, authentication, mobility event generation, etc. in association with the UE 100. The SMF 115 may perform management functions associated with the PDU session of the UE 101. For example, the SMF 135 may perform session management functions such as session establishment, modification, release, and maintenance of a tunnel between the UPF 120 and the base station 105, functions of allocating and managing an Internet Protocol (IP) address of the UE 100, network functions such as user plane selection and control, etc. The UPF 120 may perform a data processing function of transmitting data sent by the UE 100 to the DN 125 as an external network or transmitting data obtained from the DN 125 to the UE 100. In addition, the UPF 120 may perform network functions such as acting as an anchor between radio access technologies (RATs), providing a connection between the PDU session and the AF 170, packet routing and forwarding, packet inspection, applying user plane policies, performing service usage reporting, buffering, etc. The PCF 155 may manage operator policy information for providing services in the 5G system, and the UDM 160 may perform functions such as generating authentication information for 3GPP security, managing a list of network functions (NFs) supporting the UE 100, managing subscription information, etc. Figure 1In the example of , during the UE registration process, the UE 100 may send identification information (requested S-NSSAI) associated with the network slice that the UE is to request to the AMF 120, and the AMF 120 may provide the UE 100 with information (allowed NSSAI) associated with the network slices allowed for the UE 100 in consideration of the requested S-NSSAI, subscriber information, etc. In order to perform data transmission or reception with respect to a predetermined data network (DN) via the allowed network slice (allowed NSSAI), the UE 100 may request generation of a PDU session to a data network name (DNN) associated with a network slice selected from among the allowed network slices, and may perform data transmission or reception via the generated PDU session.

[0064] In addition, different network slice identifier systems may be used for different network operators. Therefore, when the UE is in a roaming state, the network slice identifier of the UE in the visited network (i.e., the visited public land mobile network (V-PLMN) S-NSSAI) and the slice identifier in the home network (e.g., the home public land mobile network (H-PLMN) S-NSSAI) may have different systems. The UE in a roaming state may store mapping information about the allowed slice sets (allowed NSSAIs) and configured slice sets (configured NSSAIs) in the visited network, associated with the H-PLMN S-NSSAI of each network slice in each network slice set as configuration information, and based on this, the UE policy received from the home network (e.g., a rule indicating which service requires a session using which H-PLMN S-NSSAI) may be applied.

[0065] In an embodiment of the present disclosure, PCF 155 is a network function responsible for policy and charging, and is classified into access and mobility policy (AM policy) indicating a policy associated with UE access and mobility, user equipment (UE) policy indicating a policy associated with the UE, and session management (SM) policy indicating a policy associated with the session of the UE. When an AM policy association (or UE policy association) is established in order to control the AM policy (or UE policy) of the UE, PCF 155 can perform installation / transmission of a policy control request (PCR) trigger with respect to AMF 110, which policy control request (PCR) trigger indicates that predefined information is provided to PCF 155 when a predetermined condition is met. When a trigger condition included in the installed / received PCF trigger is met, AMF 110 can perform a policy update request with respect to PCF 155. The policy update request may include information predefined for each purpose of the PCR trigger.

[0066] In an embodiment of the present disclosure, with respect to a UE in a roaming state in a 5G system (for example, when the UE is using a service in a visited network different from a home network), in a case where congestion occurs in at least one of the 5G network entities in the network slice used for each PDU session (5G network entities in the control plane and / or user plane constituting the network slice) (network slice congestion case), in a case where it is necessary to temporarily or permanently stop the use of a predetermined network slice due to problems in the operation in the network (operation and management (OAM) case), in a case where the SLA is not met, in a case where it is necessary to temporarily or permanently stop the use of the corresponding network slice, a method for determining a new network slice and a method for moving all or some of the PDU sessions belonging to the predetermined network slice to a target network slice (i.e., a network slice remapping method) are proposed. In addition, in an embodiment of the present disclosure, when network slice remapping is performed with respect to a UE in a roaming state, a method for updating a rule indicating whether to use a network slice for each service and stored in the UE as configuration information (i.e., a UE routing selection policy (URSP) rule in a UE policy) is proposed. By referring to the above description Figure 1 The description is understandable Figures 2 to 8 The basic characteristics of each NF involved in the process of the embodiment. When the UE is in a roaming state, V-PCF and H-PCF refer to the PCF of the visited network and the PCF of the home network, respectively, and V-NRF and H-NRF refer to the NRF of the visited network and the NRF of the home network, respectively.

[0067] In addition, when the UE is in roaming state, Figures 2 to 8 The entity with the symbol of (V-)PCF among the network entities in refers to the V-PCF as the PCF supporting slice remapping in the visited network. When the UE is not in a roaming state, the entity refers to the PCF supporting slice remapping.

[0068] Figure 2 2. It is a diagram showing a method for installing an AM policy-based PCR trigger to support slice remapping during UE registration according to an embodiment of the present disclosure.

[0069] In operation 201, in the UE registration process, the UE sends a registration request message via a base station (RAN), and the base station (RAN) transmits the registration request message to the AMF.

[0070] In operation 202, when authentication of the UE is required, the AMF Figure 1 The AUSF and UDM described perform authentication of the UE.

[0071] In operation 203, the AMF performs PCF selection.

[0072] In this case, the AMF may perform PCF selection and discovery by considering whether the PCF supports slice remapping. The AMF may use an NRF (not shown) to perform reception (i.e., discovery) of information associated with the PCF to be selected, or may utilize information associated with the PCF stored as configuration information in the UE when selecting the PCF.

[0073] In this case, in the case where the AMF performs PCF discovery via the NRF and requests information associated with the PCF from the NRF (for example, in the case where the information is requested by using an NF discovery request), the AMF may operate as follows. When the AMF supports slice remapping, the AMF may include information for requesting the PCF that supports slice remapping in the request message sent to the NRF. When the information of the PCF requesting support for slice remapping is included in the request message obtained from the AMF, the NRF may identify / select the PCF that supports slice remapping, and send a response message including information associated with the PCF that supports slice remapping to the AMF. In addition, in the case where the UE is in a roaming state, the AMF may send a request message including information for requesting the PCF that supports slice remapping to the V-NRF, and the V-NRF may send a request message or information for requesting the PCF that supports slice remapping to the H-NRF, may receive information associated with the H-PCF from the H-NRF, and may transmit it to the AMF.

[0074] The AMF may perform an AMF policy association establishment procedure with the PCF selected in operation 203.

[0075] In operation 204, the AMF may send an AM policy control generation request message (Npcf_AMPolicyControl_Create Request) to the selected (V-)PCF, the message including at least one of information notifying an endpoint, SUPI, and slice remapping.

[0076] The notification endpoint indicates the network address of the AMF, and the subscription permanent identifier (SUPI) refers to the identifier of the UE (ie, UE ID). The slice remapping information indicates whether the AMF supports slice remapping.

[0077] In operation 205, the (V-)PCF generates an AM policy association ID to identify the AM policy association based on the information received from the AMF in operation 204, and may generate AM policy information.

[0078] In this case, the (V-)PCF may request (in this case, the UE ID is included in the request message) and receive subscription information associated with the UE from the UDR or UDM (not shown), and the received subscription information may include information indicating a replacement S-NSSAI that may be used for each S-NSSAI.

[0079] Specifically, the response message (Npcf_AMPolicyControl_Create Response) sent by the (V-)PCF to the AMF in operation 205 may include at least one of a result, an AM policy association ID, a PCR trigger required for slice remapping, a PCR trigger for a change of the allowed NSSAI, and AM policy information. The result refers to the result of the request to generate an AM policy association, and may include a value indicating success or failure of the generation of the AM policy association.

[0080] The AM policy association ID refers to identifier information used to identify the generated AM policy association.

[0081] The information associated with the PCR trigger required for slice remapping may be information indicating that the AMF needs to report information associated with the network slice that needs to be remapped to the (V-)PCF in the event that a network slice that needs to be remapped occurs.

[0082] When AMF supports slice remapping, the (V-)PCF may include information associated with the PCR triggers required for slice remapping in the AM Policy Control Generation Response message sent to the AMF.

[0083] When the UE is not in roaming state, the AMF sends slice remapping information indicating whether slice remapping is supported to the PCF. When the UE is in roaming state, the AMF sends slice remapping information indicating whether slice remapping is supported to the V-PCF.

[0084] When receiving information associated with a PCR trigger required for slice remapping and a network slice that needs to be remapped occurs, the AMF may provide information associated with the network slice that needs to be remapped to the V-PCF based on the information associated with the PCR trigger required for slice remapping, and the V-PCF may determine a new network slice to replace the network slice that needs to be remapped. Subsequently, the V-PCF may provide the newly determined network slice information to the AMF.

[0085] The information associated with the PCR trigger of the change of the allowed NSSAI may be information indicated by the (V-)PCF that the AMF needs to report the change of the allowed NSSAI to the (V-)PCF when the change of the allowed NSSAI occurs.

[0086] When receiving information associated with a PCR trigger of a change in allowed NSSAI from the (V-)PCF, when the allowed NSSAI (e.g., allowed network slice identifier list) changes, the AMF may report the changed allowed NSSAI to the PCF.

[0087] When determining a new network slice for a network slice that needs to be remapped, the (V-)PCF may determine the new network slice based on the allowed NSSAI (or the changed allowed NSSAI). Therefore, when the (V-)PCF provides the AMF with information associated with the PCR trigger required for slice remapping, it may also provide information associated with the changed PCR trigger of the allowed NSSAI.

[0088] AM policy information is policy information, and AMF can perform UE access and mobility management based on this information.

[0089] In operation 206, the AMF may determine to perform a UE policy association establishment procedure.

[0090] When there is a (V-)PCF selected in the AM policy association (ie, the PCF selected in operation 203), the AMF can select a corresponding PCF and use it for UE policy association. When there is no selected (V-)PCF, the PCF selection process of operation 203 can be performed.

[0091] In operation 206, the AMF may send a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including at least one of the notification endpoint, SUPI, H-PCF ID, and slice remapping information to the selected (V-)PCF.

[0092] The Notification Endpoint indicates the network address of the AMF, and the SUPI indicates the identifier of the UE (ie, UE ID).

[0093] The H-PCF ID may be included in the UE policy control generation request message when the UE is in a roaming state, and may be the identifier information of the H-PCF. Figure 2 In the example of , operation 209 is performed immediately after operation 206, and operations 207 and 208 to be described below are omitted.

[0094] The slice remapping information indicates whether AMF supports slice remapping. H-PCF can identify whether AMF supports slice remapping based on the slice remapping information.

[0095] In operation 207 , the V-PCF may transmit a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including the information received in operation 206 to the H-PCF corresponding to the H-PCF ID received from the AMF in operation 206 .

[0096] In operation 208, based on the information received from the AMF, the H-PCF generates a UE policy association ID to identify the UE policy association, and may generate UE policy information.

[0097] In this case, although not Figure 2 As shown in the figure, the H-PCF can request subscription information associated with the UE from the UDR or UDM (in this case, the UE ID is included in the request message) and can receive subscription information associated with the UE.

[0098] Specifically, the UE policy control generation response message (Npcf_UEPolicyControl_Create Response) sent by the H-PCF to the AMF via the (V-)PCF in operations 208 and 209 may include at least one of the result, the UE policy association ID, the PCR trigger of the change of the remapped slice, and the UE policy information.

[0099] The result refers to the result of the request to generate the UE policy association in operation 207, and may include a value indicating success or failure of the generation of the UE policy association.

[0100] The UE policy association ID refers to identifier information used to identify the generated UE policy association.

[0101] The PCR trigger for the change of the remapped slice is used to instruct / trigger the AMF to report the network slice that needs to be remapped and the information of the newly determined network slice to the PCF when a new network slice is determined for the network slice that needs to be remapped. The new network slice can be determined by the V-PCF and can be transmitted to the AMF.

[0102] When AMF supports slice remapping, the H-PCF may include at least one of the result, the UE policy association ID, the PCR trigger of the change of the remapped slice and the UE policy information in the UE policy control generation response message sent to the AMF via the (V-)PCF.

[0103] In an embodiment of the present disclosure, when the UE is not in a roaming state, the AMF may report information associated with the network slice that needs to be remapped and the newly determined network slice to the PCF, and when the UE is in a roaming state, the AMF may report information associated with the network slice that needs to be remapped and the newly determined network slice to the V-PCF.

[0104] After receiving information associated with the PCR trigger of the change of the remapped slice and determining a new network slice of the network slice that needs to be remapped, the AMF can report the information associated with the network slice that needs to be remapped and the newly determined network slice to the H-PCF via the V-PCF.

[0105] The H-PCF may update UE policy information based on information received via the V-PCF and may send it to the UE.

[0106] In operation 209, the (V-)PCF may transmit a UE policy control generation response message including the information received from the H-PCF to the AMF.

[0107] When the UE is not in roaming state, the (V-)PCF can act as Figure 2 In this case, the (V-)PCF may operate and generate the above information in the same manner as the H-PCF of operation 208, and the generated information may be included in the UE policy control generation response message transmitted to the AMF.

[0108] In operation 210, a UE configuration update procedure is performed. In this case, the AMF may send a UE policy container including UE policy information received from the (V-)PCF to the UE via the base station (RAN).

[0109] Based on the network slice selection policy (NSSP) information included in the URSP rule in the UE policy information, the UE can determine which S-NSSAI and DNN's PDU session is used for application service transmission.

[0110] In operation 211, when the (V-)PCF receives a notification response indicating reception of a UE policy container from the UE, the (V-)PCF may send a UE policy control update request message indicating the notification response to the H-PCF.

[0111] In operation 212 , the H-PCF may send a UE policy control update response message to the (V-)PCF in response to the UE policy control update request message of operation 211 .

[0112] In operation 213, the remaining UE registration procedures may be performed.

[0113] Figure 31 is a diagram showing a method for determining a new network slice via an AM policy process when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure. Figure 3 In the embodiment of the present invention, it is assumed that the AMF has received from the (V-)PCF the same Figure 2 The embodiment described herein is related to the PCR trigger required for slice remapping, the PCR trigger for the allowed change of NSSAI information, and the PCR trigger for the change of remapped slice information. Figure 3 The embodiments can be used with Figure 2 Combination of embodiments.

[0114] In operation 301, the AMF identifies that a situation requiring slice remapping has occurred (the situation requiring slice remapping may include, for example, a situation where an unavailable network slice occurs, a situation where a congested network slice occurs, a situation where a network slice that is planned to be terminated due to OAM occurs, a situation where a network slice that cannot meet the SLA occurs, etc.).

[0115] In operation 302, when a situation requiring slice remapping is identified in operation 301, when there is information associated with a PCR trigger required for slice remapping received from the V-PCF (i.e., when information indicating that a report to the V-PCF is required when a situation requiring slice remapping occurs is received from the V-PCF), the AMF may send an AM policy control update request message (Npcf_AMPolicyControl_Update request) to the V-PCF, which includes at least one of an AM association ID, a VPLMN S-NSSAI, an unavailable slice indicator, an allowed NSSAI, and a mapping of allowed NSSAIs.

[0116] The AM policy association ID may be an identifier for identifying the AM policy association established between the UE and the PCF.

[0117] The information associated with the S-NSSAI that needs to be remapped that has been described in advance is information associated with the network slice that needs to be remapped, and the information associated with the S-NSSAI that needs to be remapped may include at least one of a VPLMN S-NSSAI and an unavailable slice indicator. The VPLMN S-NSSAI is identifier information associated with a network slice that needs to be remapped, and the unavailable slice indicator is an indicator indicating a network slice that needs to be remapped. For example, in a case where the VPLMN S-NSSAI is included in the AM policy control update request message in a predetermined manner and indicates a network slice that needs to be remapped, the unavailable slice indicator may be omitted from the AM policy control update request message. As another example, in a case where the unavailable slice indicator is included in the AM policy control update request message and the V-PCF identifies the VPLMN S-NSSAI corresponding to the unavailable slice indicator, the VPLMN S-NSSAI may be omitted from the AM policy control update request message.

[0118] The allowed NSSAI may include changed allowed NSSAI information.

[0119] Mapping of allowed NSSAI is information included when the UE is in a roaming state, and indicates information associated with H-PLMN S-NSSAI to which V-PLMN S-NSSAI included in allowed NSSAI is respectively mapped.

[0120] In operation 303, the V-PCF identifies the S-NSSAI that needs to be remapped based on the information received from the AMF in operation 302, and determines a new VPLMN S-NSSAI (i.e., new S-NSSAI) for the network slice that needs to be remapped. The new VPLMN S-NSSAI is identification information of the network slice that replaces the S-NSSAI that needs to be remapped.

[0121] The response message that the V-PCF sends to the AMF in operation 303 may include the result and new S-NSSAI information.

[0122] The result refers to the result of the request of operation 302 and indicates the success or failure of the remapping.

[0123] The new S-NSSAI may be a new VPLMN S-NSSAI selected / determined by the V-PCF for the network slice that needs to be remapped. The new VPLMN S-NSSAI may be determined based on the allowed NSSAI included in the AM policy control update request message. For example, the new VPLMN S-NSSAI may be determined within the allowed NSSAI.

[0124] The AM policy association ID may be an identifier for identifying the AM policy association established between the UE and the PCF.

[0125] In operation 304, according to Figure 2 In an embodiment of the present invention, the AMF is in a state where the information associated with the PCF trigger of the change of the remapped slice has been received from the V-PCF, and in a case where the AMF receives the newly determined network slice information (i.e., the new S-NSSAI) from the V-PCF in operation 303 or directly determines the new network slice information (i.e., the new S-NSSAI) despite not receiving the new S-NSSAI from the V-PCF in operations 302 and 303, the AMF may be triggered based on the information associated with the PCF trigger of the change of the remapped slice in operation 304, and a UE policy control update request message including at least one of the UE policy association ID, the S-NSSAI to be remapped, the new S-NSSAI, and the mapping of the new S-NSSAI may be sent to the V-PCF in operation 305. The mapping of the new S-NSSAI is included only when the UE is in a roaming state.

[0126] The UE policy association ID is an identifier for identifying the UE policy association established between the UE and the PCF.

[0127] The information associated with the S-NSSAI that needs to be remapped is the identifier information associated with the network slice that needs to be remapped. An indicator indicating the network slice that needs to be remapped may be additionally included in the UE policy control update request message.

[0128] The information associated with the mapping of the S-NSSAI that needs to be remapped refers to the H-PLMN S-NSSAI information corresponding to the identifier of the network slice that needs to be remapped.

[0129] The new S-NSSAI may be a new VPLMN S-NSSAI selected / determined directly by the V-PCF or AMF for the network slice that needs to be remapped. The new VPLMN S-NSSAI may be determined based on the allowed NSSAI. For example, the new VPLMN S-NSSAI may be determined within the allowed NSSAI.

[0130] The mapping of new-SNSSAI refers to the H-PLMNS-NSSAI information corresponding to the newly selected / determined network slice (new S-NSSAI).

[0131] In operation 306, the V-PCF sends a UE policy control update request message including the information received from the AMF in operation 305 to the corresponding H-PCF.

[0132] In operation 307, the H-PCF may identify the V-PLMN S-NSSAI and the H-PLMN S-NSSAI of the network slice that needs to be remapped (e.g., the unavailable network slice) based on the information associated with the mapping of the S-NSSAI that needs to be remapped and the S-NSSAI that needs to be remapped received in operation 306. In addition, based on the mapping of the new S-NSSAI and the new S-NSSAI information received in operation 306, the H-PCF may identify the V-PLMN S-NSSAI and the H-PLMN S-NSSAI (new S-NSSAI) of the newly selected network slice.

[0133] In operation 307, the H-PCF may update the URSP rules (transmitted to the UE and including information of the required network slice for each UE service) based on the identified information, and may transmit the UE policy container including the updated URSP rules to the UE via the AMF according to the UE configuration update procedure.

[0134] In the updated URSP rules, the S-NSSAI that needs to be remapped may be deleted from the list of S-NSSAIs that match the service, or the S-NSSAI that needs to be remapped may be listed with a low priority, and a newly selected network slice (e.g., a new S-NSSAI) may be used instead.

[0135] When the UE receives an updated URSP policy, the UE can determine which network slice's PDU session to use for transmission of future generated services based on the updated URSP policy.

[0136] In operation 308 , the H-PCF transmits a response message including the result of the request message of operation 306 to the V-PCF.

[0137] In operation 309, the V-PCF sends a response message including the result of the request message of operation 305 to the AMF.

[0138] In operation 310, the AMF may continue the procedure for moving the PDU sessions included in the S-NSSAI that needs to be remapped (associated with the S-NSSAI that needs to be remapped) to the new VPLMN S-NSSAI identified / selected in operation 307. In this case, service continuity may be provided in the following manner: a PDU session is generated in the new VPLMN S-NSSAI for each PDU session associated with the S-NSSAI that needs to be remapped, and the PDU session associated with the S-NSSAI that needs to be remapped is released.

[0139] Figure 41 is a diagram showing a method for installing a PCR trigger based on a UE policy to support slice remapping during a UE registration process according to an embodiment of the present disclosure. Figure 4 In the process of AM strategy Figure 2 Compared with the process of Figure 2 Operations 204 and 205.

[0140] In operation 401, in the UE registration process, the UE sends a registration request message via a base station (RAN), and the RAN transmits the registration request message to the AMF.

[0141] In operation 402, when authentication of the UE is required, the AMF Figure 1 The AUSF and UDM described perform authentication of the UE.

[0142] In operation 403, the AMF performs PCF selection.

[0143] In this case, the AMF may perform PCF selection and discovery by considering whether the PCF supports slice remapping. The AMF may use an NRF (not shown) to perform reception (i.e., discovery) of information associated with the PCF to be selected, or may utilize information associated with the PCF stored as configuration information in the UE when selecting the PCF.

[0144] In this case, in the case where the AMF performs PCF discovery via the NRF and requests information associated with the PCF from the NRF (for example, in the case where the information is requested by using an NF discovery request), the AMF may operate as follows. When the AMF supports slice remapping, the AMF may include information for requesting the PCF that supports slice remapping in the request message sent to the NRF. When the information of the PCF requesting support for slice remapping is included in the request message obtained from the AMF, the NRF may identify / select the PCF that supports slice remapping and send a response message including information associated with the PCF that supports slice remapping to the AMF. In addition, in the case where the UE is in a roaming state, the AMF may send a request message including information for requesting the PCF that supports slice remapping to the V-NRF, and the V-NRF may send a request message or information for requesting the PCF that supports slice remapping to the H-NRF, may receive information associated with the H-PCF from the H-NRF, and may transmit it to the AMF.

[0145] The AMF may perform an AMF policy association establishment procedure with the PCF selected in operation 403.

[0146] In operation 404, the AMF may determine to perform a UE policy association establishment procedure. When the (V-)PCF selected in the AM policy association exists (i.e., when the (V-)PCF selected in operation 403 exists), the AMF may select a corresponding PCF and use it for UE policy association. When the (V-)PCF selected in operation 403 does not exist, the above-mentioned PCF selection procedure may be performed in operation 403.

[0147] In operation 405, the AMF may send a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including at least one of the notification endpoint, SUPI, H-PCF ID, and slice remapping information to the selected (V-)PCF.

[0148] The Notification Endpoint indicates the network address of the AMF, and the SUPI indicates the identifier of the UE (ie, UE ID).

[0149] The H-PCF ID may be included in the UE policy control generation request message when the UE is in a roaming state, and may be identifier information of the H-PCF. When the UE is not in a roaming state, operations 406 and 407 may be omitted.

[0150] The slice remapping information indicates whether AMF supports slice remapping.

[0151] In operation 406 , the V-PCF may transmit a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including the information received in operation 405 to the H-PCF corresponding to the H-PCFID received from the AMF in operation 405 .

[0152] In operation 407, based on the information received from the AMF, the H-PCF generates a UE policy association ID to identify the UE policy association, and may generate UE policy information.

[0153] In this case, although not Figure 4 As shown in the figure, the H-PCF may request subscription information associated with the UE from the UDR or UDM (in this case, the UE ID is included in the request message), and may receive subscription information associated with the UE, and the received subscription information may include information indicating an alternative S-NSSAI that may be used for each S-NSSAI.

[0154] Specifically, the UE policy control generation response message (Npcf_UEPolicyControl_Create Response) sent by the H-PCF to the AMF via the (V-)PCF may include at least one of the result, the UE policy association ID, the PCR trigger of the slice remapping, the PCR trigger of the allowed NSSAI change, and the UE policy information.

[0155] The result refers to the result of the request to generate the UE policy association in operation 406, and may include a value indicating success or failure of the generation of the UE policy association.

[0156] The UE policy association ID refers to identifier information used to identify the generated UE policy association.

[0157] The PCR trigger for slice remapping is information used to instruct / trigger the AMF to report information associated with the network slice that needs to be remapped (information associated with the S-NSSAI that needs to be remapped) to the PCF when an unavailable network slice occurs.

[0158] When the UE is not in roaming state, the AMF may report information associated with the S-NSSAI that needs to be remapped to the PCF based on the PCR trigger of the slice remapping. When the UE is in roaming state, the AMF may report information associated with the S-NSSAI that needs to be remapped to the V-PCF, and the V-PCF may transmit information associated with the S-NSSAI that needs to be remapped to the H-PCF.

[0159] In the present disclosure, a new network slice to replace a network slice that needs to be remapped can be generated by Figure 5 The H-PCF in the example or Figure 7 The V-PCF is determined in the example of , which will be described later.

[0160] According to the method of determining a new network slice for a network slice that needs to be remapped by the V-PCF, the V-PCF that receives the UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including information associated with the S-NSSAI that needs to be remapped from the AMF can determine / select a new network slice, and can transmit the information associated with the new network slice to the H-PCF, and the H-PCF can provide the information associated with the new network slice to the AMF again via the V-PCF. In this case, when a network slice that needs to be remapped occurs, the AMF can provide the V-PCF with information associated with the network slice that needs to be remapped based on the PCR trigger of the slice remapping received in advance from the V-PCF, and the V-PCF can determine the new network slice. Based on the PCF trigger of the slice remapping, the V-PCF can send information associated with the network slice that needs to be remapped and the network slice determined by the V-PCF to the H-PCF, the H-PCF can send a response message to the V-PCF, and the V-PCF can provide the newly determined network slice information to the AMF. Based on the information received from the V-PCF associated with the network slice that needs to be remapped and the newly determined network slice, the H-PCF can perform a UE policy update.

[0161] According to the method of determining a new network slice for a network slice that needs to be remapped by the H-PCF, the V-PCF that receives a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including information associated with the S-NSSAI that needs to be remapped from the AMF can transmit the information associated with the S-NSSAI that needs to be remapped to the H-PCF, and the H-PCF can determine / select a new network slice, and can provide the information associated with the new network slice to the AMF via the V-PCF. In this case, when a network slice that needs to be remapped occurs, the AMF can provide the V-PCF with information associated with the network slice that needs to be remapped based on a PCR trigger of slice remapping received in advance from the V-PCF, and the V-PCF can transmit the information associated with the network slice that needs to be remapped received from the AMF to the H-PCF based on the PCR trigger of the slice remapping. The H-PCF can determine / select a new network slice to replace the network slice that needs to be remapped, and can send the information associated with the newly determined network slice to the AMF via the V-PCF. Based on the information received from the V-PCF associated with the network slice that needs to be remapped and the newly determined network slice, the H-PCF can perform a UE policy update.

[0162] In the information included in the UE policy control generation response message (Npcf_UEPolicyControl_Create Response) sent by the H-PCF to the AMF via the (V-)PCF in operation 407, the PCR trigger for change of the applied NSSAI is information for indicating / triggering the AMF to report the changed allowed NSSAI by the (V-)PCF when the allowed NSSAI changes in the AMF.

[0163] When a PCR trigger of a change of allowed NSSAI is received, when the allowed NSSAI (allowed slice identifier list) changes, the AMF may send a UE policy control update (Npcf_UEPolicyControl_Update) including the changed allowed NSSAI to the (V-)PCF.

[0164] UE policy information is information transmitted to the UE and may include at least one of an access network discovery and selection policy (ANDSP) rule and a URSP rule, the ANDSP rule including access network selection related information of the UE, and the URSP rule including information associated with a mapping of S-NSSAI and DNN, the S-NSSAI and DNN being related to a PDU session for sending or receiving application services of the UE.

[0165] The UE policy information may be determined by the (H-)PCF according to the network operation policy.

[0166] In operation 408, the (V-)PCF may transmit a UE policy control generation response message (Npcf_UEPolicyControl_Create Response) including the information received from the H-PCF to the AMF.

[0167] When the UE is not in roaming state, the (V-)PCF can act as Figure 4 In this case, the (V-)PCF may operate and generate the above information in the same manner as the H-PCF of operation 407, and the generated information may be included in the UE policy control generation response message transmitted to the AMF.

[0168] In operation 409, a UE configuration update procedure is performed. In this case, the AMF may send a UE policy container including UE policy information received from the (V-)PCF to the UE via the base station (RAN).

[0169] Based on the network slice selection policy (NSSP) information included in the URSP rule in the UE policy information, the UE can determine which S-NSSAI and DNN's PDU session is used for application service transmission.

[0170] In operation 410, when the (V-)PCF receives a notification response indicating reception of a UE policy container from the UE, the (V-)PCF may transmit a UE policy control update request message (Npcf_UEPolicyControl_Update Request) indicating the notification response to the H-PCF.

[0171] In operation 411 , the H-PCF may send a UE policy control update response message (Npcf_UEPolicyControl_Update Response) to the (V-)PCF in response to the UE policy control update request message in operation 410 .

[0172] In operation 412, the remaining UE registration procedures may be performed.

[0173] Figure 5 1 is a diagram showing a method for determining a new network slice via a UE policy process when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure. Figure 5 In the embodiments of the present invention, it is assumed that the AMF has received information associated with the PCR trigger required for slice remapping and the PCR trigger of the allowed NSSAI change, which has been referred to in Figure 3 Therefore, Figure 5 The embodiments can be used with Figure 3 Combination of embodiments.

[0174] In operation 501, the AMF identifies that a situation requiring slice remapping has occurred (the situation requiring slice remapping may include, for example, a situation where an unavailable network slice occurs, a situation where a congested network slice occurs, a situation where a network slice that is planned to be terminated due to OAM occurs, a situation where a network slice that cannot meet the SLA occurs, etc.).

[0175] When the AMF identifies in operation 501 that slice remapping is required and there is information associated with the PCF trigger of slice remapping received from the V-PCF (i.e., when information is received from the V-PCF indicating that a report needs to be made to the V-PCF when a situation requiring slice remapping occurs), the AMF may send an AM policy control update request message (Npcf_UEPolicyControl_Update Request) to the V-PCF in operation 502, the message including at least one of a UE policy association ID, a VPLMN S-NSSAI, an unavailable slice indicator, an allowed NSSAI, and a mapping of allowed NSSAIs.

[0176] The UE policy association ID is an identifier for identifying the UE policy association established between the UE and the PCF.

[0177] The VPLMN S-NSSAI and the unavailable slice indicator refer to identifier information associated with a network slice that needs to be remapped and an indicator indicating the network slice that needs to be remapped, respectively. As described above, the information associated with the S-NSSAI that needs to be remapped may include at least one of the VPLMN S-NSSAI and the unavailable slice indicator. Therefore, if Figure 3 As described in the embodiments, one of the VPLMN S-NSSAI and the unavailable slice indicator may be omitted.

[0178] The allowed NSSAI may include changed allowed NSSAI information.

[0179] Mapping of allowed NSSAI is information included when the UE is in a roaming state, and indicates information associated with H-PLMN S-NSSAI to which V-PLMN S-NSSAI included in allowed NSSAI is respectively mapped.

[0180] In operation 503, in an AM policy control update request message (Npcf_UEPolicyControl_Update Request) sent to the H-PCF, the V-PCF may include at least one of the UE policy association ID, the VPLMN S-NSSAI, the unavailable slice indicator, the allowed NSSAI, and the mapping of the allowed NSSAI received from the AMF in operation 502.

[0181] In operation 504, the H-PCF may identify mapping information between the V-PLMN S-NSSAI and the H-PLMN S-NSSAI required to determine the network slice based on the information received from the V-PCF in operation 503, or based on a PCR trigger of an allowed NSSAI change provided in a UE policy association.

[0182] The H-PCF can identify the S-NSSAI that needs to be remapped and the H-PLMN S-NSSAI corresponding thereto, and can determine / select a new VPLMN S-NSSAI (i.e., a new VPLMN S-NSSAI) of the network slice that needs to be remapped and / or a new HPLMN S-NSSAI corresponding to the new VPLMN S-NSSAI.

[0183] In addition, the H-PCF may identify information associated with the S-NSSAI that needs to be remapped (i.e., the VPLMN S-NSSAI) and the newly determined VPLMN S-NSSAI (i.e., the new VPLMN S-NSSAI) to replace the VPLMN S-NSSAI, as well as information associated with the H-PLMN S-NSSAI and the new HPLMN S-NSSAI corresponding to the VPLMN S-NSSAI that needs to be remapped and the new VPLMN S-NSSAI, respectively.

[0184] The H-PCF may update the URSP rules (transmitted to the UE and including information of the required network slice for each UE service) based on the identified information, and may transmit the UE policy container including the updated URSP rules to the UE via the AMF according to the UE configuration update procedure.

[0185] In the updated URSP rules, the S-NSSAI that needs to be remapped can be deleted from the list of S-NSSAIs that match the service, or the S-NSSAI that needs to be remapped can be listed with a low priority, and the newly selected network slice (new S-NSSAI) can be used instead.

[0186] When the UE receives an updated URSP policy, the UE can determine which network slice's PDU session to use for transmission of future generated services based on the updated URSP policy.

[0187] In operation 505 , the H-PCF may include the network slice information determined / selected / identified in operation 504 (e.g., the new VPLMN S-NSSAI or the new HPLMN S-NSSAI or both) in a response message in response to operation 503 .

[0188] In operation 506 , the V-PCF may include slice information associated with the VPLMN (ie, the new VPLMN S-NSSAI) received in operation 505 in a response message in response to operation 502 .

[0189] In operation 507, the AMF may continue the process for moving the PDU sessions included in the S-NSSAI that needs to be remapped (associated with the S-NSSAI that needs to be remapped) to the new VPLMN S-NSSAI determined / selected / identified in operation 504. In this case, service continuity may be provided in a manner of generating a PDU session for each PDU session associated with the S-NSSAI that needs to be remapped in the new VPLMN S-NSSAI and releasing the PDU session associated with the S-NSSAI that needs to be remapped.

[0190] Figure 61 is a diagram showing a method of reporting a change in allowed NSSAI to the H-PCF via a UE policy procedure when allowed NSSAI changes according to an embodiment of the present disclosure. Figure 2 or Figure 4 In an embodiment of the (V-)PCF, when the AMF receives information associated with a PCR trigger of a change in the allowed NSSAI and recognizes that the allowed NSSAI has changed, it may perform Figure 6 Therefore, Figure 6 The embodiments can be used with Figure 2 or Figure 4 Combination of embodiments.

[0191] In operation 601, the AMF recognizes that the allowed NSSAI has changed.

[0192] When the AMF recognizes in operation 601 that the allowed NSSAI is changed (i.e., when a new S-NSSAI is added to or deleted from the allowed NSSAI, or is changed), and as Figure 2 or Figure 4 As described in the example of , when there is a PCF trigger of a change in the allowed NSSAI received by the AMF from the V-PCF, the AMF may transmit a UE policy control update request message (Npcf_UEPolicyControl_Update Request) including at least one of the UE policy association ID, the allowed NSSAI, and the mapping of the allowed NSSAI to the V-PCF in operation 602.

[0193] In this case, when the UE is in a roaming state, operations 603 and 604 may be applicable.

[0194] The UE policy association ID is an identifier for identifying the UE policy association established between the UE and the PCF.

[0195] The allowed NSSAI may include changed allowed NSSAI information.

[0196] Mapping of allowed NSSAI is information included in the UE policy control update request message when the UE is in a roaming state, and indicates information associated with H-PLMN S-NSSAI to which V-PLMN S-NSSAI included in allowed NSSAI is respectively mapped.

[0197] When the UE is in a roaming state, in operation 603, the V-PCF transmits the information received from the AMF in operation 602 to the H-PCF.

[0198] Based on the UE Policy Association ID or Based on the H-PCF ID When the H-PCF ID is included in the UE Policy Control Update Request message received in operation 602, the V-PCF may determine / identify the H-PCF to which the message is to be sent.

[0199] In operation 604, the H-PCF may identify how to change the allowed NSSAI of the UE in the roaming state based on the allowed NSSAI received from the V-PCF in operation 603, and may identify the H-PLMN S-NSSAI to which the corresponding allowed NSSAI is mapped based on the mapping of the allowed NSSAI. Subsequently, in operation 604, the H-PCF sends a response message including the UE policy update result to the V-PCF.

[0200] In operation 605, the V-PCF sends a response message including the UE policy update result received from the H-PCF to the AMF.

[0201] Figure 7 1 is a diagram showing a method for determining a new network slice by the (V-)PCF via a UE policy procedure when a network slice that needs to be remapped occurs according to an embodiment of the present disclosure. Figure 4 In an embodiment of the present invention, when using a method for determining by the V-PCF a new network slice that requires a remapped network slice, Figure 7 The embodiments can be used with Figure 4 Combination of embodiments.

[0202] In operation 701, the AMF identifies that a situation requiring slice remapping has occurred (the situation requiring slice remapping may include, for example, a situation where an unavailable network slice occurs, a situation where a congested network slice occurs, a situation where a network slice is scheduled to be terminated due to OAM, a situation where a network slice cannot meet the SLA, etc.).

[0203] When the AMF identifies in operation 701 that slice remapping is required and there is information associated with the PCF trigger of slice remapping received from the V-PCF (i.e., when information is received from the V-PCF indicating that a report needs to be made to the V-PCF when a situation requiring slice remapping occurs), the AMF may send an AM policy control update request message (Npcf_UEPolicyControl_Update Request) to the V-PCF in operation 702, the message including at least one of a UE policy association ID, a VPLMN S-NSSAI, an unavailable slice indicator, an allowed NSSAI, and a mapping of allowed NSSAIs.

[0204] The UE policy association ID is an identifier for identifying the UE policy association established between the UE and the PCF.

[0205] The VPLMN S-NSSAI and the unavailable slice indicator refer to identifier information associated with a network slice that needs to be remapped and an indicator indicating the network slice that needs to be remapped, respectively. As described above, one of the VPLMN S-NSSAI and the unavailable slice indicator may be omitted.

[0206] The allowed NSSAI may include changed allowed NSSAI information.

[0207] Mapping of allowed NSSAI is information included when the UE is in a roaming state, and indicates information associated with H-PLMN S-NSSAI to which V-PLMN S-NSSAI included in allowed NSSAI is respectively mapped.

[0208] In operation 703, the V-PCF may determine / select a new VPLMN S-NSSAI (i.e., a new VPLMN S-NSSAI) for the network slice that needs to be remapped based on the information received from the AMF in operation 702.

[0209] In operation 704, the V-PCF may send a UE policy control update request message (Npcf_UEPolicyControl_Update Request) to the H-PCF, which includes the UE policy association ID, the VPLMN S-NSSAI, and at least one of the H-PLMN S-NSSAI corresponding to the VPLMN S-NSSAI, the new VPLMN S-NSSAI, and the H-PLMN S-NSSAI corresponding to the new VPLMN S-NSSAI. In this case, when the UE policy control update request message sent by the V-PCF to the H-PCF includes the new VPLMN S-NSSAI, the UE policy control update request message may include the H-PLMN S-NSSAI corresponding to the new VPLMN S-NSSAI.

[0210] As another example, the V-PCF may include only information associated with the H-PLMN S-NSSAI corresponding to the new VPLMN S-NSSAI in the UE Policy Control Update Request message sent to the H-PCF.

[0211] The UE policy association ID is an identifier for identifying the UE policy association established between the UE and the PCF.

[0212] VPLMN S-NSSAI refers to information associated with slices that need to be remapped, which the V-PCF receives from the AMF in operation 702.

[0213] The H-PLMN S-NSSAI corresponding to the VPLMN S-NSSAI refers to information associated with the H-PLMN S-NSSAI corresponding to the VPLMN S-NSSAI.

[0214] The new VPLMN S-NSSAI refers to information associated with a newly selected VPLMN S-NSSAI to replace the VPLMN S-NSSAI in operation 703 .

[0215] The H-PLMN S-NSSAI corresponding to the new VPLMN S-NSSAI refers to information associated with the HPLMN S-NSSAI corresponding to the newly selected VPLMN S-NSSAI.

[0216] In operation 705, based on the information received from the V-PCF in operation 704, the H-PCF may identify information associated with the S-NSSAI that needs to be remapped and the newly selected S-NSSAI. That is, the S-NSSAI that needs to be remapped and the H-PLMN S-NSSAI corresponding to the newly selected VPLMN S-NSSAI, respectively, may be identified, and the UE policy for the UE may be updated based on the identified information. Specifically, the H-PCF may update the URSP rule including information associated with the mapping between the DNN and the S-NSSAI in the application service and the UE policy, and may send the updated URSP policy to the UE.

[0217] In operation 706 , the H-PCF may send a response message including the result of the request message of operation 704 to the V-PCF.

[0218] In operation 707, the V-PCF sends a response message to the AMF, which includes the result of the request message of operation 702 and a newly selected S-NSSAI (ie, a new VPLMN S-NSSAI) of the S-NSSAI that needs to be remapped.

[0219] In operation 708, the AMF may continue the process for moving the PDU sessions (associated with the S-NSSAI that needs to be remapped) included in the S-NSSAI that needs to be remapped to the new VPLMN S-NSSAI received in operation 707. In this case, service continuity may be provided in a manner of generating a PDU session for each PDU session associated with the S-NSSAI that needs to be remapped in the new VPLMN S-NSSAI and releasing the PDU session associated with the S-NSSAI that needs to be remapped.

[0220] Figure 82 is a diagram showing a method for installing a UE policy-based PCR trigger to support AMF-based slice remapping during UE registration according to an embodiment of the present disclosure.

[0221] In operation 801, in the UE registration process, the UE sends a registration request message via a base station (RAN), and the RAN transmits the registration request message to the AMF.

[0222] In operation 802, when authentication of the UE is required, the AMF Figure 1 The AUSF and UDM described perform authentication of the UE.

[0223] In operation 803, the AMF performs PCF selection.

[0224] In this case, the AMF may perform PCF selection and discovery by considering whether the PCF supports slice remapping. The AMF may use an NRF (not shown) to perform reception (i.e., discovery) of information associated with the PCF to be selected, or may utilize information associated with the PCF stored as configuration information in the UE when selecting the PCF.

[0225] In this case, in the case where the AMF performs PCF discovery via the NRF and requests information associated with the PCF from the NRF (for example, in the case where the information is requested by using an NF discovery request), the AMF may operate as follows. When the AMF supports slice remapping, the AMF may include information for requesting the PCF that supports slice remapping in the request message sent to the NRF. When the information of the PCF requesting support for slice remapping is included in the request message obtained from the AMF, the NRF may identify / select the PCF that supports slice remapping, and send a response message including information associated with the PCF that supports slice remapping to the AMF. In addition, in the case where the UE is in a roaming state, the AMF may send a request message including information for requesting the PCF that supports slice remapping to the V-NRF, and the V-NRF may send a request message or information for requesting the PCF that supports slice remapping to the H-NRF, may receive information associated with the H-PCF from the H-NRF, and may transmit it to the AMF.

[0226] The AMF may perform an AMF policy association establishment procedure with the PCF selected in operation 803.

[0227] In operation 804, the AMF may determine to perform a UE policy association establishment procedure. When the (V-) PCF selected in the AM policy association exists (i.e., when the (V-) PCF selected in operation 803 exists), the AMF may select a corresponding PCF and use it for UE policy association. When the (V-) PCF selected in operation 803 does not exist, the above-mentioned PCF selection procedure may be performed in operation 803.

[0228] In operation 805, the AMF may send a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including at least one of the notification endpoint, SUPI, H-PCF ID, and slice remapping information to the selected (V-)PCF.

[0229] The Notification Endpoint indicates the network address of the AMF, and the SUPI indicates the identifier of the UE (ie, UE ID).

[0230] The H-PCF ID may be included in the UE policy control generation request message when the UE is in a roaming state, and may be identifier information of the H-PCF. When the UE is not in a roaming state, operations 806 and 807 may be omitted.

[0231] The slice remapping information indicates whether AMF supports slice remapping.

[0232] In operation 806 , the V-PCF may transmit a UE policy control generation request message (Npcf_UEPolicyControl_Create Request) including the information received in operation 805 to the H-PCF corresponding to the H-PCF ID received from the AMF in operation 805 .

[0233] In operation 807, based on the information received from the AMF, the H-PCF generates a UE policy association ID to identify the UE policy association, and may generate UE policy information.

[0234] In this case, although not Figure 8 As shown in the figure, the H-PCF can request subscription information associated with the UE from the UDR or UDM (in this case, the UE ID is included in the request message) and can receive subscription information associated with the UE.

[0235] Specifically, the UE policy control generation response message (Npcf_UEPolicyControl_Create Response) sent by the H-PCF to the AMF in operation 807 may include at least one of a result, a UE policy association ID, a PCR trigger of a change in the remapped slice, and UE policy information.

[0236] The result refers to the result of the request to generate the UE policy association in operation 806, and may include a value indicating success or failure of the generation of the UE policy association.

[0237] The UE policy association ID refers to identifier information used to identify the generated UE policy association.

[0238] The PCR trigger for the change of the remapped slice may be information indicating that the AMF needs to report information associated with the network slice that needs to be remapped and the newly determined network slice (ie, the remapped slice) to the (H-) PCF via the (V-) PCF to replace the corresponding network slice when the network slice that needs to be remapped occurs. When receiving the information associated with the network slice that needs to be remapped and the remapped slice, the (H-) PCF may update the UE policy, etc., when necessary.

[0239] That is, after receiving the PCR trigger of the change of the remapped slice from the H-PCF via the V-PCF, when a situation occurs that requires slice remapping (for example, when an available network slice occurs, a congested network slice occurs, a network slice is planned to be terminated due to OAM, a network slice that cannot meet the SLA occurs, etc.), the AMF can determine the remapped slice (for example, a new VPLMN S-NSSAI) to replace the network slice that needs to be remapped, and can report the identifier information of the network slice that needs to be remapped and the identifier information of the determined remapped slice to the PCF.

[0240] When the UE is not in roaming state, the AMF may report to the PCF the identifier information of the network slice that needs to be remapped and the identifier information of the remapped slice determined / selected by the AMF. When the UE is in roaming state, the AMF may report to the V-PCF the identifier information of the network slice that needs to be remapped and the identifier information of the remapped slice determined / selected by the AMF, and the V-PCF may report to the H-PCF the information received from the AMF.

[0241] UE policy information is information transmitted to the UE and may include at least one of an ANDSP rule and a URSP rule, the ANDSP rule including information related to access network selection of the UE, and the URSP rule including information associated with a mapping of a PDU session and related S-NSSAI and DNN for sending or receiving application services of the UE.

[0242] The UE policy information may be determined by the (H-)PCF according to the network operation policy.

[0243] In operation 808, the (V-)PCF may transmit a UE policy control generation response message (Npcf_UEPolicyControl_Create Response) including the information received from the H-PCF to the AMF.

[0244] When the UE is not in roaming state, the (V-)PCF can act as Figure 8 In this case, the (V-)PCF may operate and generate the above information in the same manner as the H-PCF in operation 807, and the generated information may be included in the UE policy control generation response message transmitted to the AMF.

[0245] In operation 809, a UE configuration update procedure is performed. In this case, the AMF may send a UE policy container to the UE via the base station (RAN), the UE policy container including the UE policy information received from the (V-) PCF.

[0246] Based on the network slice selection policy (NSSP) information included in the URSP rule in the UE policy information, the UE can determine which S-NSSAI and DNN's PDU session is used for application service transmission.

[0247] In operation 810, when the V-PCF receives a notification response indicating reception of a UE policy container from the UE, the (V-)PCF may transmit a UE policy control update request message (Npcf_UEPolicyControl_Update Request) indicating the notification response to the H-PCF.

[0248] In operation 811 , the H-PCF may send a UE policy control update response message (Npcf_UEPolicyControl_Update Response) to the (V-)PCF in response to the UE policy control update request message in operation 810 .

[0249] In operation 812, the remaining UE registration procedures may be performed.

[0250] According to the above-mentioned embodiments of the present disclosure, in a 5G system, the UE can effectively determine a new network slice to replace a problematic / unavailable network slice when the UE is in or not in a roaming state, and can move the UE's service to the new network slice, thereby ensuring service continuity. In addition, according to an embodiment of the present disclosure, the URSP rule indicating the network slice required for each service can be updated based on the problematic / unavailable network slice and the new network slice.

[0251] Fig. 9 is a diagram showing a configuration of a network entity in a wireless communication system according to an embodiment of the present disclosure. Fig. 9 The network entity can be Figures 1 to 8 One of the network entities described in the embodiments, such as UE, RAN, AMF, SMF, PCF (V-PCF or H-PCF), etc.

[0252] like Fig. 9 As shown, the network entity may include a processor 900, a transceiver 905, and a memory 910. Figures 1 to 8 The communication method of the network entity described in the embodiment of the present invention can be operated by the processor 900, the transceiver 905 and the memory 910 of the network entity. However, the components of the network entity are not limited to the above examples. For example, the network entity may include more or fewer components than the above components. In addition, the processor 900, the transceiver 905 and the memory 910 may be embodied as at least one chip.

[0253] The transceiver 905 is a general term for a receiver of a network entity and a transmitter of a network entity, and signal transmission or reception with a UE or another network entity can be performed via the transceiver 905. The signal transmitted or received may include at least one of control information and data. To this end, the transceiver 905 may include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies a received signal and down-converts the frequency of the signal, and the like. This is merely an example of the transceiver 905, and the components of the transceiver 905 are not limited to the RF transmitter and the RF receiver. The transceiver 905 may include a wired and / or wireless transceiver, and may include various configurations for signal transmission or reception. In addition, the transceiver 905 may receive a signal via a communication interface defined in the 3GPP standard, may output it to the processor 900, and may transmit a signal output from the processor 900. In addition, the transceiver 905 may receive a communication signal and output it to the processor 900, and may transmit a signal output from the processor 900 to the UE or another network entity via a network. The memory 910 may store operations according to Figures 1 to 8 The program and data required by the network entity of at least one embodiment of the embodiments of the present invention. In addition, the memory 910 can store control information and / or data included in the signal obtained by the network entity. The memory 910 can be embodied as a storage medium such as ROM, RAM, hard disk, CD-ROM, DVD, etc. or a combination of storage media. The processor 900 can control the processor 900 to perform the operation according to the embodiment of the present invention. Figures 1 to 8A series of processes for operating a network entity according to at least one of the embodiments of the present disclosure. The processor 900 may include at least one processor. The methods disclosed in the claims and / or the methods according to the embodiments described in the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software. When the processor 900 is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within the electronic device. At least one program includes instructions for causing the electronic device to execute methods according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0254] These programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage device, optical disk-ROM (CD-ROM), digital versatile disk (DVD) or other types of optical storage devices or tape cassettes. Alternatively, any combination of some or all of them can form a memory in which the program is stored. In addition, multiple such memories can be included in the electronic device. In addition, the program can be stored in an attachable storage device, which can access the electronic device through a communication network such as the Internet, intranet, local area network (LAN), wide LAN (WLAN) and storage area network (SAN) or its combination. Such a storage device can access the electronic device via an external port. In addition, a separate storage device on a communication network can access a portable electronic device.

[0255] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiments presented. However, for ease of description, the singular form or plural form is appropriately selected for the presented situation, and the present disclosure is not limited to the elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[0256] Although specific embodiments have been described in the detailed description of the present disclosure, it is apparent that various modifications and changes may be made thereto without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the embodiments set forth herein, but should be limited by the appended claims and their equivalents.

Claims

1. A method performed by an access and mobility management function (AMF) in a wireless communication system supporting network slicing, the method comprising: AMF receives a registration request message from the terminal; The first policy control function (PCF) that supports network slice remapping associated with the terminal is selected by the AMF; The AMF sends a first policy control request message to the first PCF, where the first policy control request message includes information indicating to the first PCF whether the AMF supports network slice remapping; as well as In response to sending the first policy control request message, the AMF receives a first policy control response message from the first PCF, where the first policy control response message includes first trigger information related to network slice remapping, Among them, the first trigger information indicates that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

2. The method according to claim 1, comprising: When the terminal is in a roaming state, the AMF sends a second policy control request message to the second PCF in the home network via the first PCF in the visited network, where the second policy control request message includes information indicating whether the AMF supports network slice remapping; as well as The AMF receives a second policy control response message from the second PCF via the first PCF, where the second policy control response message includes second trigger information related to network slice remapping, The second trigger information indicates that the AMF needs to send information associated with the at least one first network slice and information associated with at least one second network slice used to replace the at least one first network slice to the second PCF.

3. The method according to claim 1, wherein: The first policy control response message also includes third trigger information, which indicates that when at least one allowed network slice (allowed single network slice selection assistance information (allowed NSSAI)) changes in the AMF, the AMF needs to send information associated with the change to the first PCF.

4. The method according to claim 1, further comprising: In a case where the AMF identifies that network slice remapping is required, the AMF sends a first policy control update request message to the first PCF based on the first trigger information, where the first policy control update request message includes information associated with the at least one first network slice; as well as In response to the policy control update request message, a response message is received by the AMF from the first PCF, the response message including information associated with at least one second network slice used to replace the at least one first network slice.

5. The method according to claim 1, wherein: The information associated with the at least one first network slice includes identification information of the at least one first network slice and at least one of an indicator indicating that the at least one first network slice is a network slice requiring network slice remapping.

6. The method according to claim 4, further comprising: The AMF sends a second policy control update request message to the first PCF, where the second policy control update request message includes information associated with the at least one first network slice, a first home public land mobile network (H-PLMN) S-NSSAI information corresponding to an identifier of the at least one first network slice, information associated with the at least one second network slice, and a second H-PLMN S-NSSAI information corresponding to an identifier of the at least one second network slice.

7. The method according to claim 1, wherein: The at least one second network slice used to replace the at least one first network slice is determined by the AMF or the first PCF.

8. An access and mobility management function (AMF) in a wireless communication system supporting network slicing, the AMF comprising: Transceiver; and The processor is configured as: receiving a registration request message from a terminal via a transceiver, Selecting a first policy control function (PCF) that supports terminal-dependent network slice remapping, sending a first policy control request message to the first PCF via the transceiver, wherein the first policy control request message includes information indicating to the first PCF whether the AMF supports network slice remapping, and In response to sending the first policy control request message, receiving a first policy control response message from the first PCF via the transceiver, wherein the first policy control response message includes first trigger information related to network slice remapping, Among them, the first trigger information indicates that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

9. The AMF according to claim 8, wherein: The AMF is applied to operate in a method according to one of claims 2 to 7 .

10. A method performed by a first policy control function (PCF) in a wireless communication system supporting network slicing, the method comprising: A first PCF supporting network slice remapping receives a first policy control request message from an AMF, wherein the first policy control request message includes information indicating whether an access and mobility management function (AMF) supports network slice remapping, and the AMF receives a registration request message from a terminal; as well as In response to receiving the first policy control request message, the first PCF sends a first policy control response message to the AMF, where the first policy control response message includes first trigger information related to network slice remapping, Among them, the first trigger information indicates that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF needs to send information associated with the at least one first network slice to the first PCF.

11. The method according to claim 10, comprising: Receiving, by the first PCF of the visited network, a second policy control request message from the AMF, where the second policy control request message includes information indicating whether the AMF supports network slice remapping; as well as The first PCF sends a second policy control response message to the AMF, where the second policy control response message includes second trigger information related to network slice remapping and is received from a second PCF of the home network. The second trigger information instructs the AMF to send information associated with the at least one first network slice and information associated with at least one second network slice used to replace the at least one first network slice to the second PCF.

12. The method according to claim 10, wherein: The first policy control response message also includes third trigger information, which indicates that when at least one allowed network slice (allowed single network slice selection assistance information (allowed NSSAI)) changes in the AMF, the AMF sends information associated with the change to the first PCF.

13. The method according to claim 10, further comprising: Receiving, by the first PCF from the AMF based on the first trigger information, a first policy control update request message, wherein the first policy control update request message includes information associated with the at least one first network slice; as well as In response to the policy control update request message, the first PCF sends a response message to the AMF, wherein the response message includes information associated with at least one second network slice used to replace the at least one first network slice.

14. A first policy control function (PCF) in a wireless communication system supporting network slicing, the first PCF comprising: Transceiver; and The processor is configured as: receiving, via the transceiver, a first policy control request message from an AMF, the first policy control request message including information indicating whether an access and mobility management function (AMF) supports network slice remapping, the AMF receiving a registration request message from a terminal, and In response to receiving the first policy control request message, sending a first policy control response message to the AMF via the transceiver, wherein the first policy control response message includes first trigger information related to network slice remapping, Among them, the first trigger information indicates that when at least one first network slice requiring network slice remapping appears in the AMF, the AMF sends information associated with the at least one first network slice to the first PCF.

15. The first PCF according to claim 14, wherein: The first PCF is applied to operate with a method according to one of claims 11 to 13 .

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