KR20240043042A - Method and apparatus for changing network slice in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and apparatus for efficiently changing a network slice in a wireless communication system. According to an embodiment of the present disclosure, a method performed by AMF in a wireless communication system supporting a network slice includes the first to be changed. A process of determining a network slice, a process of selecting a second network slice replacing the first network slice, and providing a policy control function by sending a first message containing information about the first and second network slices. A process of transmitting to a policy control function (PCF) and receiving a second message containing updated UE Route Selection Policy (URSP) information based on information about the first and second network slices. and transmitting a third message including information indicating that the first network slice is unavailable based on the updated URSP information to the terminal through a radio access network (RAN).

Description

Method and apparatus for changing a network slice in a wireless communication system {METHOD AND APPARATUS FOR CHANGING NETWORK SLICE IN WIRELESS COMMUNICATION SYSTEM}

This disclosure relates to a communication method and device in a wireless communication system supporting network slices.

5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and includes sub-6 GHz ('Sub 6GHz') bands such as 3.5 gigahertz (3.5 GHz) as well as millimeter wave (mm) bands such as 28 GHz and 39 GHz. It is also possible to implement it in the ultra-high frequency band ('Above 6GHz') called Wave. In addition, in the case of 6G mobile communication technology, which is called the system of Beyond 5G, Terra is working to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low delay time that is reduced to one-tenth. Implementation in Terahertz bands (e.g., 95 GHz to 3 THz) is being considered.

In the early days of 5G mobile communication technology, there were concerns about ultra-wideband services (enhanced Mobile BroadBand, eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). With the goal of satisfying service support and performance requirements, efficient use of ultra-high frequency resources, including beamforming and massive array multiple input/output (Massive MIMO) to alleviate radio wave path loss in ultra-high frequency bands and increase radio transmission distance. Various numerology support (multiple subcarrier interval operation, etc.) and dynamic operation of slot format, initial access technology to support multi-beam transmission and broadband, definition and operation of BWP (Band-Width Part), large capacity New channel coding methods such as LDPC (Low Density Parity Check) codes for data transmission and Polar Code for highly reliable transmission of control information, L2 pre-processing, and dedicated services specialized for specific services. Standardization of network slicing, etc., which provides networks, has been carried out.

Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology, considering the services that 5G mobile communication technology was intended to support, based on the vehicle's own location and status information. V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience, and NR-U (New Radio Unlicensed), which aims to operate a system that meets various regulatory requirements in unlicensed bands. ), NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with the terrestrial network is impossible, positioning, etc. Physical layer standardization for technology is in progress.

In addition, IAB (IAB) provides a node for expanding the network service area by integrating intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, and wireless backhaul links and access links. Integrated Access and Backhaul, Mobility Enhancement including Conditional Handover and DAPS (Dual Active Protocol Stack) handover, and 2-step Random Access (2-step RACH for simplification of random access procedures) Standardization in the field of wireless interface architecture/protocol for technologies such as NR) is also in progress, and 5G baseline for incorporating Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technology Standardization in the field of system architecture/services for architecture (e.g., Service based Architecture, Service based Interface) and Mobile Edge Computing (MEC), which provides services based on the location of the terminal, is also in progress.

When this 5G mobile communication system is commercialized, an explosive increase in connected devices will be connected to the communication network. Accordingly, it is expected that strengthening the functions and performance of the 5G mobile communication system and integrated operation of connected devices will be necessary. To this end, eXtended Reality (XR) and Artificial Intelligence are designed to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR). , AI) and machine learning (ML), new research will be conducted on 5G performance improvement and complexity reduction, AI service support, metaverse service support, and drone communication.

In addition, the development of these 5G mobile communication systems includes new waveforms, full dimensional MIMO (FD-MIMO), and array antennas to ensure coverage in the terahertz band of 6G mobile communication technology. , multi-antenna transmission technology such as Large Scale Antenna, metamaterial-based lens and antenna to improve coverage of terahertz band signals, high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum), RIS ( In addition to Reconfigurable Intelligent Surface technology, Full Duplex technology, satellite, and AI (Artificial Intelligence) to improve the frequency efficiency of 6G mobile communication technology and system network are utilized from the design stage and end-to-end. -to-End) Development of AI-based communication technology that realizes system optimization by internalizing AI support functions, and next-generation distributed computing technology that realizes services of complexity beyond the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could be the basis for .

The present disclosure provides a method and apparatus for efficiently changing a network slice in a wireless communication system.

The present disclosure provides a method and apparatus for efficiently changing a network slice without establishing a new PDU session in a wireless communication system.

According to an embodiment of the present disclosure, a method performed by an access and mobility management function (AMF) in a wireless communication system supporting a network slice includes a process of determining a first network slice to be changed, and the first network slice. A process of selecting a replacement second network slice, a process of transmitting a first message containing information about the first and second network slices to a policy control function (PCF) that provides a policy control function, and A process of receiving a second message including updated UE Route Selection Policy (URSP) information based on information about the first and second network slices, and the first message based on the updated URSP information. It includes transmitting a third message including information indicating that the network slice is unavailable to the terminal through a radio access network (RAN).

According to an embodiment of the present disclosure, in a wireless communication system supporting a network slice, the AMF determines a communication interface and a first network slice to be changed, selects a second network slice to replace the first network slice, and Through a communication interface, a first message containing information about the first and second network slices is sent to a PCF providing a policy control function, and through the communication interface, a first message containing information about the first and second network slices is sent to the PCF. Receive a second message containing updated terminal path selection policy (URSP) information based on the information, and indicating, through the communication interface, that the first network slice is unavailable based on the updated URSP information. and a processor configured to transmit a third message containing information to the terminal through the RAN.

According to an embodiment of the present disclosure, in a wireless communication system supporting a network slice, the AMF determines a communication interface and a first network slice to be changed, and selects a second network slice to replace the first network slice, Through the communication interface, a first message containing PDU session-related information for the first and second network slices is transmitted to the SMF that manages the session, and through the communication interface, a first message containing PDU session-related information for the first and second network slices is transmitted from the SMF to the second network slice. Receive a second message including identification information of the PDU session for the PDU session and cause information for release of the PDU session for the first network slice, and include at least one of the information included in the second message through the communication interface. and a processor configured to transmit a third message to the terminal through the RAN.

1 is a diagram illustrating an example configuration of a wireless communication system according to an embodiment of the present disclosure;
2 is a flowchart illustrating an example of a method for changing a network slice in a wireless communication system according to an embodiment of the present disclosure;
3 is a flowchart showing another example of a method for changing a network slice in a wireless communication system according to an embodiment of the present disclosure;
FIG. 4 is a flowchart illustrating an example of a method for changing a network slice when a terminal supports network slice re-mapping in a wireless communication system according to an embodiment of the present disclosure; and
FIG. 5 is a diagram illustrating an example configuration of a network entity according to an embodiment of the present disclosure.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the attached drawings. In the following description of the present invention, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. The terms described below are defined in consideration of the functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

The advantages and features of the present disclosure and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, and the present embodiments are merely intended to ensure that the disclosure is complete and are within the scope of common knowledge in the technical field to which the present disclosure pertains. It is provided to fully inform those who have the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagram diagrams can be performed by computer program instructions.

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). Additionally, it should be noted that in some alternative execution examples it is possible for the functions mentioned in the blocks to occur out of order. For example, it is possible for two blocks shown in succession to be performed substantially at the same time, or it is possible for the blocks to be performed in reverse order depending on the corresponding function.

At this time, the term '~unit' used in this embodiment refers to software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and '~unit' performs certain roles. do. However, '~part' is not limited to software or hardware. The '~ part' may be configured to reside in an addressable storage medium and may be configured to reproduce on one or more processors. Therefore, as an example, '~ part' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and 'parts' may be combined into a smaller number of components and 'parts' or may be further separated into additional components and 'parts'. Additionally, components and 'parts' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card. Additionally, in an embodiment, '~ part' may include one or more processors.

A term used in the description of the present disclosure to identify a connection node, a term referring to network entities, a term referring to messages, a term referring to an interface between network objects, and various identification information. The terms used are exemplified for convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meaning may be used.

For convenience of explanation below, the present disclosure uses terms and names defined in the 5GS and NR standards defined by the 3rd Generation Partnership Project (3GPP) organization among currently existing communication standards. However, the present disclosure is not limited by the above terms and names, and may equally be applied to wireless communication systems that comply with other standards. This disclosure is applicable to 3GPP 5GS/NR (5th generation mobile communication standard).

In the 5G system, network slicing technology refers to a technology and structure that enables multiple virtualized, independent logical networks in one physical network. In the 5G system, network operators can provide services by configuring a virtual end-to-end network called a network slice to meet the specialized requirements of services/applications. Network slices are identified by an identifier called S-NSSAI (Single-Network Slice Selection Assistance Information), and network operators can provide communication services to terminals by providing network slice(s) to the terminal.

Specifically, in the 5G system, when a terminal registers with a network, the terminal transmits identifier information (i.e., Requested S-NSSAIs) for the network slices it wishes to request to the access and mobility management function (AMF), and the AMF sends Requested S-NSSAIs. and subscriber information, etc., and provide the terminal with information about the network slice(s) that the terminal can use (Allowed NSSAI). Even if the terminal does not provide information about the requested slice(s), the AMF can provide Allowed NSSAI to the terminal. At this time, Allowed NSSAI includes information about the default slice(s) (Default Configured NSSAI), and the terminal. It may include information on slice(s) set as default among subscribed network slices included in subscriber information (i.e., Default Subscribed S-NSSAI(s)).

If the Allowed NSSAI cannot contain any network slices (for example, the Default Configured NSSAI and Default Subscribed S-NSSAI(s) are missing or unavailable), AMF will refuse registration due to no available network slices. A network registration rejection message including an indicating cause code is transmitted to the terminal.

Meanwhile, when attempting to include an arbitrary network slice in the terminal's Allowed NSSAI, the Network Slice Admission Control (NSAC) procedure and the Network Slice-Specific Authentication and Authorization (NSSAA) procedure for the corresponding network slice must be performed. You can. In the NSAC procedure, whether to allow the network slice can be determined based on the number of terminals currently registered in a specific network slice and the maximum number of registered terminals allowed in that network slice (i.e., determining whether to include the network slice in Allowed NSSAI). In the NSSAA procedure, authentication is performed with AAA (Authentication, Authorization, and Accounting)-S, a server that performs authentication for the network slice through NSSAAF (NSSAA Function) based on the credential information for the network slice of the terminal. The procedure can be performed. At this time, it is possible to decide whether to allow the corresponding network slice by considering the authentication result (i.e., determine whether to include the corresponding slice in Allowed NSSAI).

Meanwhile, the terminal can select one of the allowed network slices for data transmission and reception to a specific data network (Data Network, DN) through the allowed network slice(s) (Allowed NSSAI(s)), and the selected network slice You can request the creation of a PDU (Packet Data Unit) session to a specific DNN (Data Network Name), and send and receive data through the created PDU session. A PDU session consists of several traffic flows, and the traffic flows can be composed of two types: GBR QoS Flow (Guaranteed Bitrate Quality-of-Service Flow) and non-GBR QoS Flow.

Meanwhile, in the 5G system, when a congestion situation occurs for a network slice (for example, when the number of registered terminals or sessions of a network slice reaches the maximum value, one or more of the Network Functions (NFs) related to the network slice (when NF is overloaded, etc.), for operational reasons (Operation and Management, OAM) for a specific network slice, or when the speed of an application on a network slice slows down, the user stops serving traffic using the network slice. There is a need for a way to efficiently move to another network slice without feeling it. A network slice in which such a problem occurs is referred to as a network slice to be terminated or a network slice to be changed.

In addition, in the present disclosure, a base station is an entity that performs resource allocation to a user equipment (UE), and includes gNode B, gNB, eNode B, eNB, Node B, BS, radio access network (RAN), and base station controller. , or at least one of the nodes on the network. The base station is an IAB-donor (Integrated Access and Backhaul-donor), which is a gNB that provides network access to the terminal(s) through a network of backhaul and access links in the NR system (hereinafter referred to as 5G system). , It may be at least one network entity among the IAB-nodes, which are RAN nodes that support NR access link(s) to the terminal(s) and backhaul link(s) to the IAB-donor or other IAB-nodes. In this disclosure, a terminal (UE) may be a cell phone, mobile station (MS), cellular phone, smartphone, computer, NB-IoT devices, sensors, as well as various wireless communication devices.

In the present disclosure, the network technology may refer to standards defined by the ITU (international telecommunication union) or 3GPP (e.g., TS 23.501, TS 23.502, TS 23.503, etc.), and are included in the network structure of FIG. 1, which will be described later. Components may refer to physical entities, software that performs individual functions, or hardware combined with software. In the drawings, reference symbols shown as Nx, such as N1, N2, N3,..., indicate known interfaces between NFs in the 5G core network (CN).

1 is a diagram illustrating an example configuration of a wireless communication system according to an embodiment of the present disclosure.

The system in FIG. 1 may include a 5G core network (5GC), a base station 110, and a terminal 100. 5GC is connected to the AMF (120) that manages the mobility of the terminal (100), the SMF (Session Management Function) (135) that manages the session, and the data network (DN) (155) and plays a data transmission role. UPF (User Plane Function) 130 that performs, PCF (policy control function) 140 that provides policy control function, UDM (user data management) (145) that provides data management functions such as subscriber data and policy control data. ), Unified Data Repository (UDR) (not shown) that stores data of various network functions (NFs) such as UDM, and network slice selection (NSSF) that selects network slice instances serving the terminal 100. function) (not shown), and a Network Slice Admission Control Function (NSACF) (not shown) that monitors and controls the number of registered terminals and PDU sessions of the network slice(s). AF (Application Function) 150, which provides application services, communicates with the 5GC.

The AMF 120 is an entity that manages access and mobility of the terminal 100. As an example, the AMF 120 can perform network functions such as registration, connection, reachability, mobility management, access confirmation, authentication, and mobility event generation of the terminal 100. there is. The SMF 135 may perform a management function for the PDU session of the terminal 101. As an example, the SMF 135 provides session management functions such as session establishment, modification, and release, IP (Internet Protocol) address allocation and management functions for the terminal 100, and network functions such as user plane selection and control. can be performed. The UPF 130 may perform a data processing function of delivering data transmitted by the terminal 100 to the DN 155, which is an external network, or delivering data received from the DN 155 to the terminal 100. In addition, the UPF (130) performs the role of anchor between radio access technologies (RAT), provides connection between PDU sessions and AF (150), packet routing and forwarding, packet inspection, and applies user plane policy. , can perform network functions such as generating traffic usage reports, buffering, etc. The PCF (140) manages operator policy information for providing services in the 5G system, and the UDM (145) generates authentication information for 3GPP security and a list of network functions (NF) supporting the terminal 100. Functions such as management and subscription information management can be performed. In the 3GPP system, the conceptual link connecting NFs in the 5G system is defined as a reference point. The following illustrates reference points included in the 5G system structure of FIG. 1. For convenience of explanation, some reference points are omitted from Figure 1.

- N1: Reference point between UE and AMF

- N2: Reference point between (R)AN and AMF

- N3: Reference point between (R)AN and UPF

- N4: Reference point between SMF and UPF

- N5: Reference point between PCF and AF

- N6: Reference point between UPF and DN

- N7: Reference point between SMF and PCF

- N8: Reference point between UDM and AMF

- N9: Reference point between two core UPFs

- N10: Reference point between UDM and SMF

- N11: Reference point between AMF and SMF

- N12: Reference point between AMF and AUSF

- N13: Reference point between UDM and authentication server function (AUSF)

- N14: Reference point between two AMFs

- N15: Reference point between PCF and AMF for non-roaming scenarios, reference point between PCF and AMF in visited network for roaming scenarios

In the present disclosure, when at least one network slice to be terminated or at least one network slice to be changed occurs, at least one new network slice that can replace it is determined/selected (e.g., a target network slice identifier (target S -NSSAI) or determine/select a new network slice identifier (new S-NSSAI)), some or all of the terminal(s) using the network slice to be terminated/changed, and some or all of the existing PDU sessions in use for each terminal We propose a technique for moving to a newly determined/selected network slice. Specifically, in this disclosure, the traffic(s) of the existing PDU session(s) corresponding to the S-NSSAI to be terminated/changed is transferred to another PDU established in the same DNN while using another S-NSSAI (i.e., a new S-NSSAI). A method and device for moving to session(s) are proposed. According to the present disclosure, when using a new S-NSSAI according to a change in S-NSSAI, the terminal 100 transfers the traffic(s) of the existing PDU session to another PDU session established in the same DNN without establishing a new PDU session. It can be sent and received through (s).

In the present disclosure, traffic belonging to an existing network slice (old S-NSSAI) is transferred to a new network slice (new S-NSSAI) by updating the UE Route Selection Policy (URSP) rule of the terminal 100 and directing immediate application of the URSP rule. We propose a method and device for moving it.

In addition, the present disclosure may provide information instructing the terminal 100 to move traffic of a PDU session belonging to an existing network slice (old S-NSSAI) to a PDU session belonging to a new network slice (new S-NSSAI). Through this, we propose a method and device for moving traffic belonging to the existing network slice (old S-NSSAI) to a new slice (new S-NSSAI). In the following embodiments, a procedure for changing one S-NSSAI to a new S-NSSAI is illustrated for convenience of explanation. However, even when changing multiple S-NSSAIs to multiple new S-NSSAIs, the embodiments of the present disclosure are the same. It can be applied in this way.

FIG. 2 is a flowchart illustrating an example of a method for changing a network slice in a wireless communication system according to an embodiment of the present disclosure. The embodiment of FIG. 2 is an update of a UE Route Selection Policy (URSP) rule of the terminal 100 and an immediate URSP. This shows a method of moving traffic belonging to an existing network slice (old S-NSSAI) to a new network slice (new S-NSSAI) by instructing the application of a rule.

At step 201, the AMF 120 determines that for a particular S-NSSAI(s) (e.g. S-NSSAI1), a change to a different S-NSSAI is required for some or all of the PDU session(s) belonging to that S-NSSAI. You can judge. AMF 120 is a different S-NSSAI (i.e. a new S-NSSAI) based on the information contained in the message received from the network data analytics function (NWDAF), network slice admission control function (NSACF), PCF, OAM, or NG-RAN. NSSAI) can decide whether to change it or not. The NWDAF is an NF that provides analysis information for 5G system operation, and the NSACF is an NF that monitors and controls the number of registered terminals and PDU sessions of network slice(s).

The message may include the UE ID(s) or PDU Session ID(s) that are subject to S-NSSAI change, and at least one S-NSSAI that needs to be changed. Additionally, the message contains information (e.g., S-NSSAI and at least one of information such as the number of currently registered terminals for each S-NSSAI, the number of registered terminals with at least one PDU session or PDN connection, the number of PDN sessions, etc.) may be included.

In step 202, the AMF 120 determines the S-NSSAI(s), UE ID(s), and PDU session that require change in S-NSSAI based on the information included in the message received in step 201 or through its own judgment. ID(s) can be determined. Here, the UE ID(s) and PDU session ID(s) are the UE ID(s) and PDU session ID(s) related to the S-NSSAI(s) that require the change.

AMF 120 determines the PDU session(s) to be changed in the old S-NSSAI (i.e., each S-NSSAI determined to require change, e.g., S-NSSAI1), for each PDU session, the new S-NSSAI -NSSAI (i.e., a new target S-NSSAI of an already established PDU session, for example, S-NSSAI2) can be determined.

At this time, when the AMF (120) determines a new S-NSSAI for the PDU session, among the PDU sessions currently established for the UE (100), the AMF (120) uses the same DNN (Data Network Name) as each PDU session that it has decided to change. ) Check whether there are other PDU session(s) with

For example, if the PDU session for which the new S-NSSAI must be determined (i.e., to be moved) is a PDU session established with S-NSSAI1 and DNN1, another UE (100) with the corresponding PDU session Among the PDU session(s), check whether there are PDU session(s) established with DNN1 and an S-NSSAI other than S-NSSAI1. If there is a PDU session(s) established with the same DNN as another S-NSSAI, the AMF 120 may determine one of the S-NSSAI(s) of the PDU session(s) as the target of the new S-NSSAI. . At this time, if there are multiple S-NSSAIs that are the target of the new S-NSSAI, the new S-NSSAI can be determined based on the information necessary to determine the target S-NSSAI received in step 201 (e.g., Among the S-NSSAI(s) of PDU session(s) established with the same DNN as other S-NSSAIs, the S-NSSAI with the relatively few (or smallest) number of registered terminals may be determined as the new S-NSSAI).

If there is no PDU session(s) established with the same DNN as another S-NSSAI, the target S-NSSAI or If the information necessary to determine the target S-NSSAI is included, the AMF 120 can select a new S-NSSAI based on that information (target to move PDU session(s) within the S-NSSAI that needs to be changed). If S-NSSAI is included, it can be determined as new S-NSSAI, or if information necessary to determine target S-NSSAI is included, new S-NSSAI can be determined based on this).

Alternatively, the operator may store alternative S-NSSAI (i.e., alternative S-NSSAI) for each S-NSSAI as configuration information in the AMF 120 through OAM or other configuration information provision method. AMF 120 creates a new S-NSSAI based on the corresponding setting information for the S-NSSAI(s) requiring change and the UE ID(s) and PDU session ID(s) to which the change is to be applied within the S-NSSAI. can be decided.

In step 203, the AMF 120 determines which of the S-NSSAI(s) of the PDU session(s) have the same DNN as each PDU session (i.e., the PDU session established with the old S-NSSAI) that it decided to change in step 202. If one is determined to be the new S-NSSAI, an Npcf_UEPolicyControl_Update request message is sent to the PCF 140 requesting that the UE Route Selection Policy (URSP) of the UE 100 be updated accordingly. The Npcf_UEPolicyControl_Update request message may include at least one of the following information: UE ID, Old S-NSSAI=S-NSSAI1, new S-NSSAI=S-NSSAI2 DNN, and update URSP rule indication.

The Old S-NSSAI represents identifier information of a network slice that needs to be changed, and the new S-NSSAI represents slice identifier information that needs to be changed.

In step 204, the PCF 140 transmits a response message to the Npcf_UEPolicyControl_Update request message received in step 203 to the AMF 204.

In step 205, the PCF (140) determines that the request message received in step 203 is a message transmitted by a PCR (Policy Control request) Trigger for network slice change previously provided to the AMF (120), or the request message received in step 203 If a request message includes information indicating URSP rule update (i.e., update URSP rule indication), the URSP rule for the UE ID is included in the request message received in step 203. Update based on the information provided. The URSP rules are rules provided as configuration information to the terminal 100, and each rule may be composed of a pair of Traffic Descriptor (TD) and Route Selection Descriptor (RSD).

The terminal 100 sends traffic matching the TD (e.g., application identifier (App ID), destination IP address, destination port number, etc.) to the RSD (e.g., S-NSSAI and/or DNN). Transmission can be attempted using a PDU session. If a PDU session corresponding to the RSD exists, the terminal 100 attempts to transmit traffic through the corresponding PDU session. Otherwise, it may request to create a PDU session corresponding to the RSD.

Specifically, in this disclosure, the PCF 140 updates the URSP rule as follows. The PCF (140) changes the RSD of rules with Old S-NSSAI or Old S-NSSAI and DNN as RSD in the request message received in step 203 in the URSP rule provided to the terminal 100 to that of new S-NSSAI. /Can be updated.

Alternatively, the PCF 140 may use the TD of rules with Old S-NSSAI or Old S-NSSAI and DNN as RSD in the request message received in step 203 within the URSP rule provided to the terminal 100, with new S-NSSAI as RSD. It can be changed/updated by adding to the TD of the rules.

Since a PDU session established with new S-NSSAI and DNN already exists, the terminal 100 can use the existing PDU session upon receiving an updated URSP rule.

In step 206, the PCF 140 transmits the Npcf_UEPolicyControl_Notify message to the AMF 120 to transmit the updated URSP rule to the UE 100. The Notify message may include at least one of UE ID and UE Policy Container (URSP rule, immediate apply required) information.

If the request message received in step 203 is a message requesting a URSP rule change due to a network slice change, the PCF 140 sends “immediate apply required” information indicating that the URSP rule will be applied immediately to the terminal 100. It can be included in the Notify message provided to (100).

In steps 207 and 208, the AMF 120 transmits at least one of the information included in the Notify message received in step 206 to the RAN (base station) 110 using a NAS message, and the RAN 110 sends the AMF 120 ) At least one of the information included in the NAS message received from ) is delivered to the UE (100).

At this time, the AMF 120 may transmit the NAS message transmitted to the terminal 100 by including “S-NSSAI to be disabled” information, and the “S-NSSAI to be disabled” information is converted to old S-NSSAI. can be set.

If the AMF 120 does not include the “S-NSSAI to be disabled” information in the NAS message transmitted to the terminal 100 in steps 207 and 208, the AMF 120 sends the terminal ( 100), the above “S-NSSAI to be disabled” information can be provided. In this way, in steps 209 and 210, the AMF 120 may provide the UE 100 with information that the old S-NSSAI will not be available in the future at a time after step 202. If the NAS message in steps 207 and 208 includes the “S-NSSAI to be disabled” information, the operations in steps 209 and 210 may be omitted. Delivery of the NAS message in steps 207 and 208 and/or steps 209 and 210 may be understood as a UE configuration update (UCU) procedure. The “S-NSSAI to be disabled” information provided by the AMF 120 to the UE 100 may be provided to the UE 100 in one of the following formats 1) to 3):

1) AMF 120 removes the old S-NSSAI from the Allowed NSSAI (i.e., list of allowed S-NSSAIs) and includes the updated Allowed NSSAI in the UE Configuration Update Command message transmitted to the UE 100. .

2) The AMF 120 includes information indicating the unavailability of the old S-NSSAI included in the Allowed NSSAI (i.e., a list of allowed S-NSSAIs) and transmits a UE Configuration Update Command message to the UE 100. Include my updated Allowed NSSAI.

3) AMF 120 includes Rejected NSSAI in the UE Configuration Update Command message transmitted to UE 100. The AMF 120 includes the Old S-NSSAI in the Rejected NSSAI and includes a Cause value for why the Old S-NSSAI is included in the rejected slice. The Cause value may represent a value indicating a change to a new S-NSSAI.

AMF (120) may transmit timer information along with “S-NSSAI to be disabled” information provided to UE (100). When the AMF 120 needs to create a new PDU session for the new S-NSSAI selected in step 202 (i.e., the new S-NSSAI is the S-NSSAI of the PDU sessions previously established for the UE 100 in step 202). (if not selected among them), timer information along with “S-NSSAI to be disabled” information may be provided to the UE (100). In step 211, the UE (100) receives the NAS message received in steps 207 and 208. If a URSP rule is included, the URSP rule saved as configuration information is updated with the received URSP rule.

When the UE (100) includes the “immediate apply required” information (information received from the PCF (140) and exists in the UE Policy Container) in the NAS message received in steps 207 and 208, the affected traffic ( In other words, if the PDU session of traffic needs to be changed according to the updated URSP rule, the updated URSP rule is immediately applied (i.e., traffic is transmitted to the PDU session according to the new URSP rule).

In addition, when the UE 100 receives the “S-NSSAI to be disabled” information (information received from the AMF 120) in steps 207 and 208 or steps 209 and 210, the UE 100 It can be decided to immediately apply the newly updated URSP rule to the existing PDU session(s) established with S-NSSAI corresponding to the “be disabled” information. In addition, the UE (100) may decide to send a release request or release it internally (i.e., local release) for the PDU session(s) corresponding to the “S-NSSAI to be disabled” information (i.e. old S-NSSAI). there is. Additionally, when the UE 100 receives the “S-NSSAI to be disabled” information (information received from the AMF 120) in steps 207 and 208 or steps 209 and 210, “S-NSSAI to be disabled” ”Do not send a PDU Session Establishment Request (PDU Session Establishment Request) message for an unavailable S-NSSAI that the information indicates.

When the terminal 100 receives timer information along with “S-NSSAI to be disabled” information in steps 207 and 208 or steps 209 and 210, the terminal 100 receives “S-NSSAI to be disabled” information after the timer expires. A release request may be transmitted for the PDU session(s) corresponding to (i.e., old S-NSSAI), or release (i.e., local release) may be performed internally in the UE (100).

In step 212, the PDU session(s) corresponding to the Old S-NSSAI is released. The PDU session(s) corresponding to the Old S-NSSAI may be released upon request by the UE 100 or may be released by triggering the AMF 120.

FIG. 3 is a flowchart showing another example of a method for changing a network slice in a wireless communication system according to an embodiment of the present disclosure. The embodiment of FIG. 3 provides the terminal 100 with a PDU session belonging to an existing network slice (old S-NSSAI). Traffic belonging to the old network slice (old S-NSSAI) is transferred to the new network slice (new S-NSSAI) by providing information instructing to move the traffic from the existing network slice (old S-NSSAI) to the PDU session(s) belonging to the new network slice (new S-NSSAI). This shows how to move to S-NSSAI).

At step 301, the AMF 120 indicates that for a specific S-NSSAI(s) (e.g., S-NSSAI1), a change to a different S-NSSAI is required for some or all of the PDU session(s) belonging to that S-NSSAI. You can judge. As in step 201 of FIG. 2, the AMF 120 changes to a different S-NSSAI (i.e., a new S-NSSAI) based on the information contained in the message received from NWDAF, NSACF, PCF, OAM, or NG-RAN. You can decide whether or not.

The message may include the UE ID(s) or PDU Session ID(s) that are subject to S-NSSAI change, and at least one S-NSSAI that needs to be changed. Additionally, the message contains information necessary to determine the target S-NSSAI or target S-NSSAI to which to move the PDU session(s) within the S-NSSAI that needs to be changed (e.g., S-NSSAIs and the current status for each S-NSSAI). At least one of information such as the number of registered terminals, the number of registered terminals having at least one PDU session or PDN connection, the number of PDN sessions, etc.) may be included.

In step 302, the AMF 120 determines the S-NSSAI(s), UE ID(s), and PDU session for which S-NSSAI needs to be changed based on the information included in the message received in step 301 or through its own judgment. ID(s) can be determined. Here, the UE ID(s) and PDU session ID(s) are the UE ID(s) and PDU session ID(s) related to the S-NSSAI(s) that require the change.

AMF 120 determines the PDU session(s) to be changed in the old S-NSSAI (i.e., each S-NSSAI determined to require change, e.g., S-NSSAI1), for each PDU session, the new S-NSSAI -NSSAI (i.e., a new target S-NSSAI of an already established PDU session, for example, S-NSSAI2) can be determined.

At this time, when the AMF 120 determines a new S-NSSAI for a PDU session, among the PDU sessions currently established for the UE 100, another PDU having the same DNN as each PDU session decided to be changed Check if session(s) exist.

For example, if the PDU session for which the new S-NSSAI must be determined (i.e., to be moved) is a PDU session established with S-NSSAI1 and DNN1, another PDU session of the UE 100 with the corresponding PDU session ( s), check whether there are PDU session(s) established with S-NSSAI other than S-NSSAI1 and DNN1. If there is a PDU session(s) established with the same DNN as another S-NSSAI, the AMF 120 may determine one of the S-NSSAI(s) of the PDU session(s) as the target of the new S-NSSAI. . At this time, if there are multiple S-NSSAIs that are the target of the new S-NSSAI, the new S-NSSAI can be determined based on the information necessary to determine the target S-NSSAI received in step 301 (e.g., other Among the S-NSSAI(s) of the PDU session(s) established with the same DNN as the S-NSSAI, the S-NSSAI with a lower number of registered terminals may be determined as the new S-NSSAI).

If there is no PDU session(s) established with the same DNN as another S-NSSAI, the target S-NSSAI or target S-NSSAI to which to move the sessions within the S-NSSAI that require changes in the message received in step 301 If the information necessary to determine is included, new S-NSSAI is selected based on that information. (If the S-NSSAI that needs to be changed contains a target S-NSSAI to which sessions will be moved, this is determined as the new S-NSSAI, or if the information necessary to determine the target S-NSSAI is included, the new S-NSSAI is based on this. NSSAI may decide).

Alternatively, the operator may store alternative S-NSSAI (i.e., alternative S-NSSAI) for each S-NSSAI as configuration information in the AMF 120 through OAM or other configuration information provision method. AMF 120 creates a new S-NSSAI based on the corresponding setting information for the S-NSSAI(s) requiring change and the UE ID(s) and PDU session ID(s) to which the change is to be applied within the S-NSSAI. can be decided.

In step 303, the AMF 120 selects one of the S-NSSAIs of the PDU sessions with the same DNN as each PDU session determined to be changed in step 302 (i.e., the PDU session established with the old S-NSSAI) as the new S-NSSAI. If it is determined, an SM (session management) Context Release request message for the PDU session for which the S-NSSAI change has been determined can be transmitted to the SMF 135. The SM Context Release request message may include at least one of the following information: SM Context ID, PDU session ID of PDU session with new S-NSSAI and the same DNN or new S-NSSAI:

The “PDU session ID of PDU session with new S-NSSAI and the same DNN” information indicates the identifier of the PDU session established with the new S-NSSAI and the same DNN.

The New S-NSSAI represents the identifier information of the network slice that will replace the old S-NSSAI determined in step 302.

Additionally, the AMF 120 may transmit the same information to the SMF 135 through an SM Context Update request message instead of the SM Context Release request message.

In step 304, the SMF 135 transmits a response message to the request message received in step 303 to the AMF 120.

In step 305, upon receiving the SM Context Release request message in step 303, the SMF 135 sends a PDU session release command (PDU session ID, PDU session ID of PDU session with new S-NSSAI and the same) to the terminal 100. A Namf_Communication_N1N2MessageTransfer request message containing at least one of the information (DNN or new S-NSSAI, Cause) is transmitted to the AMF (120).

The PDU session ID included in the N1N2MessageTransfer request message is set to the PDU session ID corresponding to the SM Context ID in the request message received in step 303, and means the PDU session ID to be released.

The “PDU session ID of PDU session with new S-NSSAI and the same DNN” information included in the N1N2MessageTransfer request message is the “PDU session ID of PDU session with new S-NSSAI and the” in the request message received in step 303. It is set to “same DNN” information and means the identifier of the PDU session to be used instead of the PDU session to be released.

The Cause may include information indicating that the PDU session release is due to a network slice change (or information indicating that a session to a new S-NSSAI is required).

When the SMF 135 receives the SM Context Update request message in step 303, the N1N2MessageTransfer request message transmitted by the SMF 135 in step 305 may include a PDU session release command or a PDU session modification command, A release timer value may be included.

In step 306, the AMF 120 transmits to the RAN 110 an N2 message including at least one of the information included in the N1N2MessageTransfer request message received in step 305.

In step 307, the RAN 110 transmits to the UE 100 an N1 message including at least one of the information included in the N2 message received in step 306.

In step 308, the UE 100 determines that the N1 message received in step 307 includes the PDU Session release command (or PDU session modification command), and that the N1 message includes “PDU session ID of PDU session with new S-NSSAI. and the same DNN” information and the Cause value indicates that the session release (or change) is due to a network slice change (or a session to a new S-NSSAI is required), the N1 message received in step 307 It can be decided to transmit the traffic(s) corresponding to the PDU session ID of to the PDU session corresponding to the “PDU session ID of PDU session with new S-NSSAI and the same DNN” information. Alternatively, if the N1 message received in step 307 includes new S-NSSAI instead of the “PDU session ID of PDU session with new S-NSSAI and the same DNN” information, the UE 100 connects to the old S-NSSAI. Among the already established PDU sessions, traffic(s) corresponding to the PDU session ID (i.e., the PDU Session ID for the PDU session for which the network slice is to be changed) is connected to the new S-NSSAI and the same DNN (i.e., the PDU session to be released). It can be decided to transmit in a PDU session with the same DNN).

Additionally, if the information received in step 307 includes the PDU session release command, the UE 100 enters the PDU session ID established with the old S-NSSAI (i.e., the PDU session ID for the session for which the network slice is to be changed). It can be determined that the PDU session corresponding to is immediately released. If the information received in step 307 includes the PDU session modification command, the terminal 100 may transmit a PDU session release request message to the AMF 120 through the RAN 110 after a certain period of time. If the release timer value is included in the PDU session modification command, the terminal 100 may transmit a PDU session release request at a time after the release timer value.

Afterwards, in step 309, the PDU session of the old S-NSSAI is released.

In the 5G system, there is a technology called Session and Service Continuity (SSC) Mode that supports session continuity for the purpose of improving user QoE (Quality-of-Experience) or supporting Mission Critical services. SSC consists of three modes, of which SSC mode 3 is called Make-Before-Break. If the network determines that it is necessary to release the SSC mode 3 PDU session that the terminal 100 is using, it can support session continuity by establishing a new PDU session that can replace the PDU session and then releasing the existing PDU session. there is. In the 5G system, before the existing PDU session of the terminal 100 is released, session continuity can be maintained by moving traffic flows that were being transmitted/received through the existing PDU session to a new PDU session.

FIG. 4 is a flowchart illustrating an example of a method for changing a network slice when a terminal supports network slice re-mapping in a wireless communication system according to an embodiment of the present disclosure.

In step 401, the terminal 100 may transmit an AN message (AN parameter, registration request) to the base station (RAN) 110. At this time, the registration request message includes a UE identifier (subscription concealed identifier (SUCI), 5G-globally unique temporary identity (5G-GUTI), or permanent equipment identifier (PEI), etc.), requested NSSAI, and UE mobility management (MM) core. At least one piece of information such as network capability may be included. In addition, when the terminal 100 supports the network slice re-mapping function, information indicating that the terminal 100 supports the network slice re-mapping capability (e.g., network slice re-mapping capability) is included in the registration request message. can be included. The network slice re-mapping capability may be included in the UE MM core network capability. Meanwhile, in step 405 or step 406, which will be described later, the terminal 100 that supports network slice re-mapping receives network slice identifier information (Mapped S-NSSAI) (Mapped S-NSSAI) mapped to the Registration message or UE configuration update message received from the AMF 120. For example, network slice identifier information for the home network (i.e., Home Public Land Mobile Network (HPLMN)) in the mapped slice information for S-NSSAI 1 (information indicating that Mapped S-NSSAI is S-NSSAI 2). (i.e., if HPLMN S-NSSAI) is included, network slice remapping can be performed using that information. When the HPLMN S-NSSAI is included in the Mapped S-NSSAI, the terminal 100 that does not support network slice re-mapping transmits a message indicating that it does not support network slice re-mapping to the network or provides the corresponding information. It can be ignored.

In step 402, the RAN 110 may select the AMF 120 based on information in the AN message received from the terminal 100.

In step 403, the RAN 110 may deliver an N2 message (including N2 parameters, registration request, etc.) to the AMF 120. The N2 parameters may include at least one of information such as selected PLMN ID, UE location information, and UE context request. Additionally, the N2 message may include a RAN ID.

In step 404, steps necessary for the UE registration procedure may be performed. AMF 120 may request and receive UE subscription information from UDM (not shown).

In step 405, the AMF 120 provides at least one of the subscribed network slice information (Subscribed S-NSSAI) of the terminal 100, support slice information for each TA (tracking area) or cell, and current location information of the terminal 100. Based on this, the network slice (Allowed NSSAI) allowed to the terminal 100 can be determined, and information about the allowed network slice (Allowed NSSAI) can be included in the Registration accept message and transmitted to the terminal 100. If the AMF 120 determines that network slice remapping is necessary for at least one of the network slices allowed to the terminal 100, if the terminal 100 supports network slice re-mapping (i.e., in step 403) (if the registration request message received by the AMF 120 includes a network slice remapping capability for the terminal 100), in at least one Allowed NSSAI transmitted by the AMF 120 to the terminal 100, if new S- If the NSSAI is not included in the at least one Allowed NSSAI, a new network slice (new S-NSSAI) that replaces the network slice (old S-NSSAI) requiring remapping can be included and the old S-NSSAI can be excluded. You can. Additionally, the AMF 120 may include information indicating that the network slice mapped to the old S-NSSAI is the new S-NSSAI along with the old S-NSSAI in the Registration accept message transmitted to the terminal 100. The information may be expressed in the form of slice information (Mapping of Allowed NSSAI) mapped to an allowed network slice. AMF 120 may include Allowed NSSAI and the Mapping of Allowed NSSAI in the Registration accept message transmitted to terminal 100. The Registration accept message is transmitted to the terminal 100 through the RAN 110.

Additionally, in step 406 after the registration procedure, if the AMF 120 determines that network slice remapping is necessary for at least one of the network slices allowed to the terminal 100, the terminal 100 supports network slice re-mapping. (i.e., when the registration request message received in step 403 includes the network slice remapping capability of the terminal 100), if the new S-NSSAI is included in at least one Allowed NSSAI transmitted to the terminal 100, If it is not included in one Allowed NSSAI, a new network slice (new S-NSSAI) for the network slice (old S-NSSAI) requiring remapping can be included and the old S-NSSAI can be excluded. Additionally, the AMF may include information indicating that the network slice mapped to the old S-NSSAI is the new S-NSSAI, along with the old S-NSSAI in the message transmitted to the terminal. The information may be expressed in the form of network slice information (Mapping of Allowed NSSAI) mapped to an allowed network slice. AMF 120 may include Allowed NSSAI and Mapping of Allowed NSSAI in the UE configuration update message transmitted to UE 100. The UE configuration update message may be transmitted to the terminal 100 through the RAN 110.

If the Registration accept message in step 405 includes the Mapping of Allowed NSSAI information, step 406 may be omitted. Additionally, if the Mapping of Allowed NSSAI information is not included in the Registration accept message in step 405, the Mapping of Allowed NSSAI information can be delivered to the terminal 100 through the UE configuration update message in step 406. In another embodiment, if a change occurs in the Mapping of Allowed NSSAI information after the Registration accept message includes the Mapping of Allowed NSSAI information and is delivered to the UE 100 in step 405, the UE configuration update in step 406 The change information can be provided to the terminal 100 through a message.

If the terminal 100 does not support network slice re-mapping in step 407, the message received in step 406 or step 407 includes Allowed NSSAI and Mapping of Allowed NSSAI, and HPLMN S is included in Mapping of Allowed NSSAI. -If NSSAI is included, the information may be ignored, or the message transmitted from the terminal 100 to the AMF 120 may include information indicating that the function is not supported or information indicating that uninterpretable information has been received. You can.

When the terminal supports network slice re-mapping, if the message received in step 406 or step 407 includes Allowed NSSAI and Mapping of Allowed NSSAI, and Mapping of Allowed NSSAI includes HPLMN S-NSSAI, The terminal 100 may operate as follows.

When the terminal 100 includes new S-NSSAI in Allowed NSSAI in the message received in step 406 or step 407, and old S-NSSAI is included in Mapped S-NSSAI information for new S-NSSAI. , the PDU session information stored in the terminal 100 is updated. Specifically, if there are PDU sessions that have the old S-NSSAI as network slice identifier information, the network slice identifier information of the corresponding PDU sessions can be changed to new S-NSSAI.

In addition, if an H-PLMN S-NSSAI (i.e. old S-NSSAI) that is not included in the Allowed NSSAI is included in the Mapping of Allowed NSSAI, the terminal 100 has the corresponding network slice as a route selection descriptor (RSD). The URSP rule (for example, a rule indicating which DNN and S-NSSAI to transmit application traffic to the terminal 100) is determined to be valid. After the terminal 100 receives the Mapping of Allowed NSSAI including the old S-NSSAI with the new S-NSSAI as the mapped slice, when application traffic matching the URSP rule with the old S-NSSAI as the RSD occurs, The terminal 100 may transmit a PDU session creation request message corresponding to the slice to which the old S-NSSAI is mapped (i.e., the new S-NSSAI) and the DNN included in the matched URSP rule to the AMF 120. If an H-PLMN S-NSSAI (ie, old S-NSSAI) that is not included in the Allowed NSSAI is included in the Mapping of Allowed NSSAI, the terminal 100 does not release the PDU session for the corresponding network slice.

As described above, according to the present disclosure, the service level agreement (SLA) concluded with the network slice contractor is satisfied by moving traffic(s) belonging to an unavailable S-NSSAI or an S-NSSAI that needs to be changed to a new S-NSSAI, You can prevent quality degradation for application users. In addition, according to the present disclosure, a new PDU session is created by moving the traffic(s) of the existing PDU session included in the S-NSSAI that needs to be changed to a PDU session established with the same DNN as the S-NSSAI different from the corresponding PDU session. By moving traffic to a new S-NSSAI without establishing a , traffic can be moved quickly with less signaling.

FIG. 5 is a diagram illustrating an example configuration of a network entity according to an embodiment of the present disclosure.

The network entity in FIG. 5 may be one of the network functions (NF) such as UE, RAN (base station), AMF, SMF, PCF, etc. described in the embodiments of FIGS. 1 to 4.

A network entity according to an embodiment of the present disclosure may include a processor 501 that controls the overall operation of the network entity, a transceiver 503 including a transmitter and a receiver, and a memory 505. Of course, it is not limited to the above example, and the network entity may include more or fewer configurations than the configuration shown in FIG. 5.

According to an embodiment of the present disclosure, the transceiver 503 may transmit and receive signals with at least one of other network entities or a terminal. Signals being transmitted and received may include at least one of control information and data.

According to an embodiment of the present disclosure, the processor 501 may generally control the operation of the network entity to perform an operation according to one or a combination of two or more of the embodiments of FIGS. 1 to 4 described above. there is. Meanwhile, the processor 501, transceiver 503, and memory 505 do not necessarily have to be implemented as separate modules, and of course can be implemented as a single component in the form of a single chip. And the processor 501 may be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor. The transceiver 503 may include at least one communication interface for transmitting and receiving signals wired/wireless with other network entities.

According to an embodiment of the present disclosure, the memory 505 may store data such as basic programs, applications, and setting information for the operation of the corresponding network entity. Additionally, the memory 505 provides stored data upon request from the processor 501. The memory 505 may be composed of a storage medium such as ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. Additionally, there may be multiple memories 505. Additionally, the processor 501 may perform at least one of the above-described embodiments based on a program for performing an operation according to at least one of the above-described embodiments of the present disclosure stored in the memory 505.

Methods according to embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented as software, a computer-readable storage medium that stores one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured to be executable by one or more processors in an electronic device (configured for execution). One or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present invention.

These programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM: Compact Disc-ROM), Digital Versatile Discs (DVDs), or other types of It can be stored in an optical storage device or magnetic cassette. Alternatively, it may be stored in a memory consisting of a combination of some or all of these. Additionally, multiple configuration memories may be included.

In addition, the program may be operated through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or a combination thereof. It may be stored on an attachable storage device that is accessible. This storage device can be connected to a device performing an embodiment of the present invention through an external port. Additionally, a separate storage device on a communication network may be connected to the device performing an embodiment of the present invention.

Claims (15)

In a method performed by an access and mobility management function (AMF) in a wireless communication system supporting network slices,
A process of determining a first network slice to be changed;
selecting a second network slice to replace the first network slice;
Transmitting a first message containing information about the first and second network slices to a policy control function (PCF) that provides a policy control function;
Receiving a second message containing updated UE Route Selection Policy (URSP) information based on the information about the first and second network slices; and
A method comprising transmitting a third message including information indicating that the first network slice is unavailable to a terminal through a radio access network (RAN) based on the updated URSP information.
According to claim 1,
Method wherein different protocol data unit (PDU) sessions established for the first and second network slices have the same data network name (DNN).
According to claim 2,
A method in which the PDU session for the second network slice is selected from among pre-established PDU sessions in the same DNN.
According to claim 3,
A method in which a PDU session with a relatively small number of registered terminals among the previously established PDU sessions is selected as the PDU session for the second network slice.
According to claim 1,
The second network slice is based on at least one of S-NSSAI (Single-Network Slice Selection Assistance Information), the number of currently registered terminals for each S-NSSAI, the number of registered terminals having at least one PDU session, and the number of PDN sessions. How to be selected.
In access and mobility management function (AMF) in a wireless communication system supporting network slices,
communication interface; and
Determine the first network slice to be changed,
Selecting a second network slice to replace the first network slice,
Transmitting, through the communication interface, a first message containing information about the first and second network slices to a policy control function (PCF) that provides a policy control function,
Through the communication interface, receive a second message containing updated UE Route Selection Policy (URSP) information based on information about the first and second network slices,
And a processor configured to transmit, through the communication interface, a third message including information indicating that the first network slice is unavailable based on the updated URSP information to a terminal through a radio access network (RAN). AMF does.
According to claim 6,
AMF, wherein different protocol data unit (PDU) sessions established for the first and second network slices have the same data network name (DNN).
According to claim 7,
AMF where the PDU session for the second network slice is selected from among pre-established PDU sessions in the same DNN.
According to claim 8,
AMF in which a PDU session with a relatively small number of registered terminals among the previously established PDU sessions is selected as the PDU session for the second network slice.
According to claim 6,
The second network slice is based on at least one of S-NSSAI (Single-Network Slice Selection Assistance Information), the number of currently registered terminals for each S-NSSAI, the number of registered terminals having at least one PDU session, and the number of PDN sessions. AMF selected.
In access and mobility management function (AMF) in a wireless communication system supporting network slices,
communication interface; and
Determine the first network slice to be changed,
Select a second network slice to replace the first network slice,
Transmitting, through the communication interface, a first message containing protocol data unit (PDU) session-related information for the first and second network slices to a session management function (SMF) that manages the session,
Through the communication interface, receive a second message from the SMF including identification information of the PDU session for the second network slice and cause information for releasing the PDU session for the first network slice,
AMF comprising a processor configured to transmit, through the communication interface, a third message including at least one of the information included in the second message to a terminal through a radio access network (RAN).
According to claim 11,
AMF, wherein different PDU sessions established for the first and second network slices have the same data network name (DNN).
According to claim 12,
AMF where the PDU session for the second network slice is selected from among pre-established PDU sessions in the same DNN.
According to claim 13,
AMF in which a PDU session with a relatively small number of registered terminals among the previously established PDU sessions is selected as the PDU session for the second network slice.
According to claim 11,
The second network slice is based on at least one of S-NSSAI (Single-Network Slice Selection Assistance Information), the number of currently registered terminals for each S-NSSAI, the number of registered terminals having at least one PDU session, and the number of PDN sessions. AMF selected.

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