Method and apparatus for supporting data communication of terminal in mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Specifically, a method performed by a terminal of a wireless communication system may comprise the steps of: receiving information for selecting a network slice from a PCF entity; identifying whether information about a network slice to which the terminal can access is included in allowed NSSAI on the basis of the information for selecting a network slice; and transmitting a registration request message to a first AMF entity on the basis of information about an available network slice if the information about a network slice to which the terminal can access is not included in the allowed NSSAI.

Description

Method and device for supporting data communication of a terminal in a mobile communication system

[0001] The present disclosure relates to a mobile communication system (or wireless communication system). Specifically, the present disclosure relates to a method and device for supporting a terminal performing data communication using a network slice in a mobile communication system (or wireless communication system).

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with 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 terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] Meanwhile, with the advancement of 5G communication systems, network slicing (or network slicing) technology has been introduced to the radio access network (RAN) and core network (CN) architectures. Accordingly, various studies are being conducted on communication systems that take network slicing (or network slicing) technology into account.

[0009] The present disclosure proposes a method and device for supporting a terminal performing data communication using a network slice.

[0010] Specifically, the present disclosure proposes a solution for a case where, in a case where a terminal roams in communication using a network slice, there is a discrepancy between the slice information received by the terminal and the slice information available in the roaming area. In particular, the present disclosure aims to solve a problem in which the terminal cannot receive a service because it cannot select a slice that can provide a service in the terminal's roaming area, and thus provides a method and device for providing information on a slice that provides a service and a public land mobile network (PLMN).

[0011] A method for processing a control signal of a terminal according to one embodiment of the present disclosure includes the steps of: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

[0012] The present disclosure relates to a method and device for supporting a terminal performing data communication using a network slice.

[0013] Specifically, through various embodiments proposed through the present disclosure, when there is a mismatch between slice information received by a roaming terminal and slice information available in a roaming area, a problem of not being able to select a slice that can provide service in the roaming area and thus not being able to receive service can be efficiently solved.

[0014] That is, according to various embodiments proposed through the present disclosure, slice and PLMN information providing services to terminals can be effectively provided so that seamless services can be provided to roaming terminals.

[0015] FIG. 1 illustrates an example of a 5G network environment according to one embodiment of the present disclosure.

[0016] FIG. 2 is a flowchart illustrating one embodiment for enabling network slice support and communication in a 5G network, according to one embodiment of the present disclosure.

[0017] FIG. 3 is a flowchart illustrating another embodiment for enabling network slice support and communication in a 5G network, according to one embodiment of the present disclosure.

[0018] FIG. 4 is a flowchart illustrating another embodiment for enabling network slice support and communication in a 5G network, according to one embodiment of the present disclosure.

[0019] FIG. 5 is a flowchart illustrating one embodiment of operations of a terminal for enabling network slice support and communication in a 5G network, according to one embodiment of the present disclosure.

[0020] FIG. 6 is a diagram showing the configuration of a terminal according to one embodiment of the present disclosure.

[0021] FIG. 7 is a diagram showing the configuration of a base station according to an embodiment of the present disclosure.

[0022] FIG. 8 is a diagram illustrating a configuration of a network entity according to one embodiment of the present disclosure.

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. In describing the embodiments, descriptions of technical details that are well-known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0024] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0025] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification. In addition, when describing the present disclosure, if a specific description of a related function or configuration is determined to unnecessarily obscure the gist of the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of the functions of the present disclosure, and may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout the specification.

[0026] At this time, it will be understood that each block of the processing flow diagrams and combinations of flow diagrams can be performed by computer program instructions. Furthermore, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function.

[0027] Here, the term '~ part' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, 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 further separated into additional components and '~ parts'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0028] In explaining the embodiments of the present disclosure, the main target is New Radio (NR), which is a wireless access network, and the core network, packet core 5G System, or 5G Core Network, or NG Core (Next Generation Core) in the 5G mobile communication standard specified by 3GPP (3rd Generation Partnership Project), a mobile communication standard standardization organization. However, the main gist of the present disclosure can be applied to other communication systems with similar technical backgrounds with slight modifications within a range that does not significantly deviate from the scope of the present disclosure, and this will be possible at the discretion of a person skilled in the art of the present disclosure.

[0029] For convenience of explanation, some terms and names defined in the 3GPP standards (standards for 5G, NR, LTE, or similar systems) may be used below. However, the present disclosure is not limited by these terms and names, and can be equally applied to systems conforming to other standards.

[0030] Hereinafter, terms used in the description to identify connection nodes, terms referring to network objects (network entities), terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms used in the present disclosure, and other terms referring to objects with equivalent technical meanings may be used.

[0031] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a radio access unit (RAN), an NG-RAN, a base station controller, or a node on a network. The base station may provide network access to terminal(s) in an LTE system or NR system.

[0032] A terminal may include a User Equipment (UE), a Mobile Station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, the term "terminal" may refer to various wireless communication devices, including mobile phones, narrow band (NB)-IoT devices, and sensors. In the present disclosure, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station.

[0033] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e.

[0034] As a representative example of a broadband wireless communication system, the LTE system adopts the Orthogonal Frequency Division Multiplexing (OFDM) method in the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method in the uplink (UL). The uplink refers to a wireless link through which a terminal transmits data or control signals to a base station, and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above multiple access method distinguishes the data or control information of each user by allocating and operating the time-frequency resources to be used to transmit data or control information to each user so that they do not overlap, that is, so as to achieve orthogonality.

[0035] As the future communications system beyond LTE, 5G communication systems must be able to freely reflect the diverse needs of users and service providers. Therefore, they must support services that simultaneously satisfy these diverse requirements. Services being considered for 5G communication systems include Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0036] In some embodiments, eMBB may aim to provide data rates that are significantly higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB should be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. Furthermore, a 5G communication system may need to provide both the peak data rate and an increased user-perceived data rate for a terminal. To meet these requirements, a 5G communication system may require improvements in various transmission and reception technologies, including improved multi-input, multi-output (MIMO) transmission technology. Furthermore, while current LTE transmits signals using a maximum 20 MHz transmission bandwidth in the 2 GHz band, a 5G communication system can use a wider frequency bandwidth than 20 MHz in the 3-6 GHz or higher 6 GHz band, thereby meeting the data rates required by the 5G communication system.

[0037] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the IoT, mMTC may require support for large-scale terminal connections within a cell, improved terminal coverage, improved battery life, and reduced terminal costs. The IoT requires the ability to support a large number of terminals (e.g., 1,000,000 terminals / km^2) within a cell, as it provides communication capabilities through the attachment of various sensors and devices. Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in shadow areas not covered by cells, such as basements, which may require wider coverage than other services provided by 5G communication systems. Terminals supporting mMTC should be comprised of low-cost terminals, and since frequent battery replacement is unlikely, very long battery lifespans, such as 10 to 15 years, may be required.

[0038] Finally, URLLC is a cellular-based wireless communication service used for specific purposes (mission-critical), such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles (UAVs), remote health care, and emergency alerts. Therefore, the communication provided by URLLC may need to provide very low latency (ultra-low latency) and very high reliability (ultra-reliability). For example, a service supporting URLLC may need to satisfy an air interface latency of less than 0.5 milliseconds and may also have a requirement for a packet error rate (PER) of less than 10^-5. Therefore, for services supporting URLLC, 5G systems may be required to provide a smaller Transmit Time Interval (TTI) than other services, while simultaneously allocating a wide range of resources in the frequency band to ensure the reliability of the communication link.

[0039] The three services considered in the aforementioned 5G communication system—eMBB, URLLC, and mMTC—can be multiplexed and transmitted in a single system. To meet the differing requirements of each service, different transmission and reception techniques and parameters may be used between the services. However, the aforementioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types applicable to this disclosure are not limited to the aforementioned examples.

[0040] Furthermore, while the embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro, or 5G (or NR, next-generation mobile communication) systems as examples, the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds or channel types. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0041] In 5G or NR systems, the Access and Mobility Management Function (AMF), which is the management entity that manages the mobility of the terminal, and the Session Management Function (SMF), which is the entity that manages the session, are implemented separately. Accordingly, unlike the 4G LTE communication system where the Mobility Management Entity (MME) performed both mobility management and session management, in 5G or NR systems, the entities that perform mobility management and session management are separated into the AMF and the SMF, respectively, which has changed the communication method and communication management method between the terminal and the network entity.

[0042] In 5G or NR systems, mobility management for non-3GPP access is performed via the AMF via the Non-3GPP Inter-Working Function (N3IWF), and session management is performed via the SMF. The AM also processes security-related information, a crucial element in mobility management.

[0043] As described above, in 4G LTE systems, the MME is responsible for both mobility management and session management. 5G or NR systems can support a non-standalone (NSA) architecture that utilizes these network entities from the 4G LTE system to perform communications.

[0044] FIG. 1 illustrates an example of a 5G network environment according to one embodiment of the present disclosure.

[0045] Referring to FIG. 1, a 5G or NR core network may be configured to include at least one of network functions (NFs) or network entities, such as a User Plane Function (UPF, 131, 131-2, 131-3), a Session Management Function (SMF, 121, 121-2, 121-3), an Access and Mobility Management Function (AMF, 111, 111-2, 111-3), a 5G Radio Access Network (RAN, 103, 103-2, 103-3), a Unified Data Management (UDM, 151), and a Policy Control Function (PCF, 161). In addition, for authentication of these entities, entities such as an Authentication Server Function (AUSF, 141) and an authentication, authorization, and accounting (AAA, not shown) may be included. Meanwhile, the 5G core network (or 5GC (5G core)) may include more functions or entities in addition to the network functions or network entities illustrated in FIG. 1.

[0046] The above AMF (111, 111-2, 111-3) is an entity for managing access and mobility of the UE (101). For example, the AMF (111, 111-2, 111-3) can perform network functions such as registration, connection, reachability, mobility management, access confirmation, authentication, and mobility event generation of the terminal (101).

[0047] The above SMF (121, 121-2, 121-3) can perform a management function for a PDU (protocol data unit) session of the UE (101). For example, the SMF (121, 121-2, 121-3) can perform a session management function through establishing, modifying, and releasing a session and maintaining a tunnel between the UPF (131, 131-2, 131-3) and the 5G RAN (103, 103-2, 103-3) required therefor, an IP (Internet protocol) address allocation and management function of the UE (101), user plane selection and control, traffic processing control in the UPF (131, 131-2, 131-3), and charging data collection control, etc., and can perform network functions.

[0048] The above UPF (131, 131-2, 131-3) performs the role of processing data of the UE (101), and can perform the role of processing data so that data transmitted by the UE (101) can be transmitted to an external network or data received from an external network can be transmitted to the UE (101). For example, the UPF (131, 131-2, 131-3) can perform network functions such as serving as an anchor between radio access technologies (RATs), packet routing and forwarding, packet inspection, applying user plane policies, creating traffic usage reports, buffering, etc.

[0049] The above UDM (151) can perform functions such as generating authentication information for 3GPP security, processing user identifiers (user IDs), managing a list of network functions (NFs) supporting the terminal (101), and managing subscription information.

[0050] The above PCF (161) can perform a function of managing operator policy information for providing services in a 5G system.

[0051] A UE (User Equipment, 101) (or Terminal) can access a 5G core network via a base station (BS, for example, a 5G RAN (103)). Meanwhile, for cases where the UE communicates via non-3GPP access, an N3IWF (N3 interworking function) may exist. When the UE accesses via non-3GPP access, session management can be controlled via the UE, non-3GPP access, N3IWF, and SMF, and mobility management can be controlled via the UE, non-3GPP access, N3IWF, and AMF.

[0052] Unlike LTE, in 5G or NR systems, entities that perform mobility management and session management are separated into AMF (111, 111-2, 111-3) and SMF (121, 121-2, 121-3). Meanwhile, 5G or NR systems are being considered for a stand-alone (SA) deployment structure that performs communication only with 5G or NR entities, and a non-stand-alone (NSA) deployment structure that uses 4G entities and 5G or NR entities together.

[0053] The communication network on which this disclosure is based assumes a 5G or 4G LTE network, but the same concept can be applied to other systems within a scope that can be understood by a person with ordinary technical skills.

[0054] The 3GPP standardized the 5G network system architecture and procedures. Mobile carriers can provide various services on 5G networks. To provide each service, mobile carriers must satisfy different service requirements (e.g., latency, communication range, data rate, bandwidth, reliability, etc.). To achieve this, mobile carriers can configure network slices and allocate network resources appropriate for specific services, either by network slice or by set of network slices. Network resources can refer to NFs (or network entities), logical resources provided by NFs, or radio resource allocations from base stations.

[0055] For example, a mobile carrier can configure network slice A to provide mobile broadband services, network slice B to provide vehicle communication services, and network slice C to provide IoT services. In other words, 5G networks can efficiently provide relevant services to terminals through network slices specialized for each service's characteristics.

[0056] The present disclosure relates to a method and device for supporting a terminal performing data communication using a network slice. In particular, in a case where a terminal roams during communication using a network slice, the present disclosure aims to solve a problem in which the terminal cannot select a slice capable of providing service in the roaming area and thus cannot receive service when the slice information received by the terminal and the slice information available in the roaming area do not match, thereby providing information on the slice providing the service and PLMN.

[0057] In the conventional technology, when a terminal roams, if the network of an operator that has an agreement with the terminal's home network (i.e., a home public land mobile network (HPLMN)) is selected, the service is provided through a visited public land mobile network (VPLMN) in the visited network. Therefore, the standard for selecting a PLMN (i.e., a VPLMN) by the terminal in the visited network is only to provide the service based on charging, etc., so the network is selected regardless of whether the network provides network slice or not, and thus, the service desired by the UE may not be provided in some cases. In another example, even if a PLMN that can provide network slice service to the terminal under better resource conditions exists, the service may not be provided smoothly to the terminal when a network that does not provide network slice or does not sufficiently support network slice is selected when providing the service during roaming. Therefore, the present disclosure describes a method for efficiently selecting a network that supports a service during roaming by considering network slice when the terminal roams.

[0058] FIG. 2 is a flowchart illustrating one embodiment for enabling network slice support and communication in a 5G network, according to one embodiment of the present disclosure.

[0059] In step 201, the terminal (101) transmits a registration request message to the AMF (111) of the HPLMN. At this time, the terminal may include an indicator in the registration request message that can indicate whether it supports slice-related policies and related updates of slice selection descriptors in relation to slices and transmit it together.

[0060] In step 203, the AMF (111) of the HPLMN transmits a registration accept message to the UE (101). At this time, the AMF (111) may include at least one of information on a PLMN to which the terminal can connect, information on access technology related to the PLMN, or information indicating whether a PLMN can be selected by considering a slice in the registration accept message transmitted to the UE (101).

[0061] According to one embodiment, in step 211, the PCF (161) may send slice selection descriptor information to the AMF (111) of the HPLMN. At this time, the slice selection descriptor information may be sent together with PLMN information and slice information supported by the corresponding PLMNs. For example, the slice selection descriptor transmitted by the PCF (161) may include PLMN information that the UE (101) can use and slice information supported by the PLMN. For example, the slice selection descriptor may include information for notifying that PLMN #1 supports slice #1 and slice #2, information for indicating that the supported access technology is 5G-cellular, etc. The slice selection descriptor transmitted from the PCF (161) to the AMF (111) may be transmitted from the AMF (111) to the UE (101).

[0062] At this time, PCF (161) transmits slice selection descriptor related information to UE (101) via AMF (111). When slice selection descriptor related information is transmitted through PCF-AMF section and AMF-UE section, AMF (111) does not open the message (i.e., the message is transparent to AMF), and AMF (111) can send slice selection descriptor related information by including it in DL (downlink) NAS (non-access stratum) transport message sent to UE (101).

[0063] Thereafter, in step 221, the UE (101) can perform communication with the network based on the received slice selection descriptor-related information. During the communication process, although not shown in FIG. 2, the UE (101) can perform PLMN selection to change the rate policy, perform a specific application, or select a PLMN that supports a specific slice.

[0064] In step 281, the UE (101) transmits a registration request message to the selected VPLMN AMF (111-3) through the 5G RAN (103-03), and in step 283, the UE (101) receives a registration accept message from the AMF (111-03) of the VPLMN through the 5G RAN (103-03).

[0065] FIG. 3 is a flowchart illustrating one embodiment for enabling network slice support and communication in a 5G network according to one embodiment of the present disclosure.

[0066] Figure 3 illustrates an example of a case where a UE (101) roams. When the PLMN and slice-related information for the terminal change in the roaming area (i.e., VPLMN), the roaming UE (101) can receive related information from the HPLMN (e.g., step 327). That is, the UE (101) performs a registration process in the roaming area (e.g., steps 321 to 322), and thereafter, when the PLMN and slice-related information change, the UE can receive related information from the HPLMN.

[0067] In Fig. 3, steps 301 to 313 are processes performed by the UE (101) for the HPLMN.

[0068] FIG. 3 illustrates an embodiment of a situation in which a registration accept message is received in response to a registration request message transmitted by a UE (101) to an AMF (111) of an HPLMN.

[0069] In step 301, the UE (101) transmits a registration request message to the HPLMN AMF (111). At this time, the UE (101) may include an indicator in the registration request message to indicate whether it supports updating slice-related policies and slice selection descriptor-related information in relation to slices.

[0070] In step 303, AMF (111) sends a registration accept message to UE (101). At this time, AMF (111) may include and send together with the registration accept message transmitted to UE (101) at least one of information on PLMNs to which UE (101) can connect, access technology information related to PLMNs, or information indicating whether a PLMN can be selected by considering slices.

[0071] According to one embodiment, in steps 311 and 313, the PCF (161) may transmit slice selection descriptor information to the UE (101) via the HPLMN AMF (111). At this time, the slice selection descriptor information may include PLMN information and slice information supported by the PLMNs. At this time, the PCF (161) transmits slice selection descriptor-related information to the UE (101) via the AMF (111). When the slice selection descriptor-related information is transmitted through the PCF-AMF section and the AMF-UE section, the AMF (111) may transmit the slice selection descriptor-related information by including it in a DL NAS transport message sent to the UE (101) without opening the message.

[0072] Steps 321 to 331 in FIG. 3 are processes performed for the VPLMN after the UE (101) moves to the VPLMN. In this process, the UE (101) can update and store PLMN information and PLMN-related slice information based on slice information and PLMN information received from the HPLMN related to PLMN and slice selection.

[0073] In step 321, the UE (101) transmits a registration request message to the VPLMN AMF (111-2). At this time, the UE (101) may also transmit an indicator to indicate whether it supports slice-related policies and related updates of slice selection descriptors in relation to slices.

[0074] In step 323, AMF (111-2) transmits a registration accept message to UE (101). At this time, AMF (111-2) may transmit together with the registration accept message transmitted to UE (101) at least one of information on PLMNs to which UE (101) can connect, information on access technology related to PLMNs, or information indicating whether a PLMN can be selected by considering slice.

[0075] At this time, the AMF (111-2) may transmit not only information such as network slice selection assistance information (NSSAI) (or single NSSAI (S-NSSAI)) for the UE (101) or allowed NSSAI (S-NSSAI) that the UE (101) can access, but also possible slice aware PLMN-NSSAI (S-NSSAI) information, which is PLMN that the UE (101) can select when considering slice information and slice information that is allowed to be used in the PLMN. This possible slice aware PLMN-NSSAI (S-NSSAI) information is an information element for the AMF (111-2) to inform the UE (101) of slice information that the UE (101) can use in the VPLMN when considering slices in the VPLMN.

[0076] For example, if there is NSSAI information included in the information that the UE (101) receives through the slice selection descriptor so that it can be used in the VPLMN, but is not included in the allowed NSSAI (S-NSSAI) that the UE (101) can use, the AMF (111-2) can transmit this to the UE (101) through an information element called possible slice aware PLMN-NSSAI (S-NSSAI) information. That is, if the slice selection descriptor includes NSSAI#1 and NSSAI#2 for VPLMN#1 (i.e., as slice information that can be used in VPLMN#1), the AMF (111-2) transmits the information of VPLMN#1 and NSSAI#1 and NSSAI#2 in the possible slice aware PLMN-NSSAI (S-NSSAI) information, thereby notifying or instructing the UE (101) to use the corresponding information.

[0077] According to another embodiment, if the NSSAI (S-NSSAI) information included in the slice selection descriptor received by the UE (101) but not included in the allowed NSSAI (S-NSSAI) that the UE (101) can use is information in another VPLMN, the AMF (111-2) can inform the UE (101) of information about the available candidate VPLMN (i.e., information about the PLMN that provides the NSSAI (S-NSSAI) and the NSSAI (S-NSSAI) information) together through an information element called the VPLMN information and the possible slice aware PLMN-NSSAI (S-NSSAI) information. That is, if the slice selection descriptor includes NSSAI#1 and NSSAI#2 for VPLMN#1, and NSSAI#1 and NSSA#2 for VPLMN#2, the AMF (111-2) notifies or instructs the UE (101) to use the information by transmitting information about VPLMN#1 and NSSAI#1 and NSSAI#2, and VPLMN#2 and NSSAI#1 and NSSAI#2 through possible slice aware PLMN-NSSAI (S-NSSAI) information. When using this information, the UE (101) can select VPLMN#2 instead of VPLMN#1 as a new PLMN and receive network slice-related information thereafter.

[0078] Thereafter, in step 325, the UE (101) can communicate with the network of the VPLMN. According to one embodiment, in step 327, the HPLMN PCF (161) transmits terminal-related slice selection descriptor information to the UE (101) through the VPLMN AMF (111-2) via the VPLMN PCF (161-2). When the slice selection descriptor-related information is transmitted through the PCF-AMF section and the AMF-UE section, the AMF (111-2) may send the slice selection descriptor-related information by including it in a DL NAS transport message sent from the AMF (111-2) to the UE (101) without opening the message.

[0079] In step 327, the slice selection descriptor information may include PLMN information, whether the PLMN supports the PLMN considering the slice, and information about the PLMN and the slice supported by the PLMN. Alternatively, the slice selection descriptor information may include slice information and information about PLMNs that support the slice.

[0080] In step 331 thereafter, the UE (101) may perform PLMN selection to select a PLMN that supports a change in rate policy, execution of a specific application, or a specific slice.

[0081] The process after step 381 in Fig. 3 is a process in which the UE (101) performs PLMN selection by selecting a new VPLMN based on updated information.

[0082] In step 381, the UE (101) transmits a registration request message to the AMF (111-3) of the newly selected VPLMN via the 5G RAN (103-03), and the registration request message may include the possible slice aware PLMN-NSSAI (S-NSSAI) information described above. In step 383, the UE (101) receives a registration accept message from the AMF (111-3).

[0083] FIG. 4 is a flowchart illustrating one embodiment for enabling network slice support and communication in a 5G network according to one embodiment of the present disclosure.

[0084] Figure 4 illustrates an example of a case where a UE (101) roams. The case of Figure 4 is an embodiment of a process for receiving slice-aware PLMN-NSSAI (S-NSSAI) related information through a registration reject (step 423). A roaming UE (101) can receive related information from the HPLMN when the PLMN and slice-related information for the terminal are changed in the roaming area.

[0085] In Fig. 4, steps 401 to 413 are processes performed by the UE (101) for the HPLMN. In Fig. 4, a registration accept message is received in response to a registration request message transmitted by the UE (101) to the AMF (111) of the HPLMN.

[0086] In step 401, the UE (101) transmits a registration request message to the HPLMN AMF (111). At this time, the UE (101) may include an indicator in the registration request message that can indicate whether it supports slice-related policies and related updates of slice selection descriptors in relation to slices and transmit it together.

[0087] In step 403, AMF (111) sends a registration accept message to UE (101). At this time, AMF (111) may include and send together with the registration accept message transmitted to UE (101) at least one of information on PLMNs to which UE (101) can connect, access technology information related to PLMNs, or information indicating whether a PLMN can be selected by considering slice.

[0088] According to one embodiment, in steps 411 and 413, the PCF (161) may transmit slice selection descriptor information to the UE (101) via the HPLMN AMF (111). At this time, the slice selection descriptor information may include PLMN information and slice information supported by the PLMNs. At this time, the PCF (161) transmits slice selection descriptor-related information to the UE via the AMF (111). When the slice selection descriptor-related information is transmitted through the PCF-AMF section and the AMF-UE section, the AMF (111) may send the slice selection descriptor-related information to the UE (101) by including it in a DL NAS transport message without opening the message.

[0089] Steps 421 to 431 in FIG. 4 are processes performed for the VPLMN after the UE (101) moves to the VPLMN. During this process, the UE (101) receives relevant information via a registration reject message. Additionally, during this process, the UE (101) can update and store information based on slice information and PLMN information received from the HPLMN regarding PLMN and slice selection.

[0090] In step 421, the UE (101) transmits a registration request message to the VPLMN AMF (111-2). At this time, the UE (101) may also transmit an indicator to indicate whether it supports slice-related policies and related updates of slice selection descriptors in relation to slices.

[0091] In step 423, AMF (111-2) transmits a registration reject message to UE (101). At this time, AMF (111-2) may transmit together with the registration reject message transmitted to UE (101) at least one of information on PLMNs to which UE (101) can connect, information on access technology related to PLMNs, or information indicating whether a PLMN can be selected by considering slice.

[0092] At this time, the AMF (111-2) may transmit not only information such as NSSAI (S-NSSAI) for the UE (101) or allowed NSSAI (S-NSSAI) that the UE (101) can access, but also possible slice aware PLMN-NSSAI (S-NSSAI) information, which is PLMN that the UE (101) can select when considering slice information and slice information that is allowed to be used in the PLMN. This possible slice aware PLMN-NSSAI (S-NSSAI) information is an information element that the AMF (111-2) uses to inform the UE (101) that the UE (101) can receive slice information from the VPLMN when considering slice in the VPLMN and that the slice information provided by the VPLMN is provided.

[0093] For example, if there is NSSAI (S-NSSAI) information included in the information that the UE (101) receives through the slice selection descriptor so that it can be used in the VPLMN, but is not included in the allowed NSSAI (S-NSSAI) that the UE (101) can use, the AMF (111-2) can transmit this to the UE (101) through an information element called possible slice aware PLMN-NSSAI (S-NSSAI) information. That is, if the slice selection descriptor includes NSSAI#1 and NSSAI#2 for VPLMN#1, the AMF (111-2) transmits the information of VPLMN#1 and NSSAI#1 and NSSAI#2 in the possible slice aware PLMN-NSSAI (S-NSSAI) information, thereby notifying or instructing the UE (101) to use the corresponding information.

[0094] According to another embodiment, if the NSSAI (S-NSSAI) information included in the slice selection descriptor received by the UE (101) but not included in the allowed NSSAI (S-NSSAI) that the UE (101) can use is information in another VPLMN, the AMF (111-2) can inform the UE (101) of information about the available candidate VPLMN (i.e., information about the PLMN that provides the NSSAI (S-NSSAI) and the NSSAI (S-NSSAI) information) together through an information element called the VPLMN information and possible slice aware PLMN-NSSAI (S-NSSAI) information. That is, if the slice selection descriptor includes NSSAI#1 and NSSAI#2 for VPLMN#1, and NSSAI#1 and NSSA#2 for VPLMN#2, the AMF (111-2) notifies or instructs the UE (101) to use the information by transmitting information about VPLMN#1 and NSSAI#1 and NSSAI#2, and VPLMN#2 and NSSAI#1 and NSSAI#2 through possible slice aware PLMN-NSSAI (S-NSSAI) information. When using this information, the UE (101) can select VPLMN#2 instead of VPLMN#1 as a new PLMN, and then receive network slice-related information.

[0095] Thereafter, in step 425, the UE (101) can communicate with the network of the VPLMN. According to one embodiment, in step 427, the HPLMN PCF (161) transmits terminal-related slice selection descriptor information to the UE (101) through the VPLMN AMF (111-2) via the VPLMN PCF (161-2). When the slice selection descriptor-related information is transmitted through the PCF-AMF section and the AMF-UE section, the AMF (111-2) may not open the message, but may send the slice selection descriptor-related information by including it in a DL NAS transport message sent from the AMF (111-2) to the UE (101).

[0096] In step 427, the slice selection descriptor information may include PLMN information, whether the PLMN supports the PLMN considering the slice, and information about the PLMN and the slice supported by the PLMN. Alternatively, the slice selection descriptor information may include slice information and information about PLMNs that support the slice.

[0097] In step 431 thereafter, the UE (101) may perform PLMN selection to select a PLMN that supports a change in rate policy, execution of a specific application, or a specific slice.

[0098] The process after step 481 in Fig. 4 is a process in which the UE (101) performs PLMN selection by selecting a new VPLMN based on the updated information.

[0099] In step 481, the UE (101) transmits a registration request message to the AMF (111-3) of the newly selected VPLMN via the 5G RAN (103-03), and the registration request message may include the possible slice aware PLMN-NSSAI (S-NSSAI) information described above. In step 483, the UE (101) receives a registration accept message from the AMF (111-3).

[0100] Meanwhile, in the process of selecting a new PLMN in step 431, the UE (101) may consider not only the information such as allowed NSSAI (S-NSSAI) and NSSAI (S-NSSAI) that the UE (101) can access, which were received from the AMF (111-2) in step 423, but also the PLMN that the terminal can select when considering the slice information described in step 423 or step 427, and the possible slice aware PLMN-NSSAI (S-NSSAI) information, which is slice information that is allowed to be used in the PLMN. That is, since the possible slice aware PLMN-NSSAI (S-NSSAI) information is an information element for notifying that the VPLMN provides slice information when the terminal considers the slice in the VPLMN, the UE (101) can transmit the possible slice aware PLMN-NSSAI (S-NSSAI) information together with the registration request message for the PLMN selected by considering the possible slice aware PLMN-NSSAI (S-NSSAI) information.

[0101] FIG. 5 is a flowchart illustrating one embodiment of operations of a terminal for enabling network slice support and communication in a 5G network according to one embodiment of the present disclosure.

[0102] In step 501, the terminal (or UE) receives slice selection descriptor information from the AMF via the base station. This slice selection descriptor information may include at least one of PLMN information, information on whether the PLMN provides a service considering a slice supported by the PLMN, or slice information supported by the PLMN. According to another embodiment, the slice selection descriptor information may include slice information and information on PLMNs supporting the slice.

[0103] In step 503, the terminal stores the received slice selection descriptor information.

[0104] Thereafter, in step 505, the terminal determines whether there is slice information that the terminal can access in the allowed NSSAI (S-NSSAI) of a specific PLMN based on the received PLMN information and slice information.

[0105] If there is slice information that the terminal can access, that is, if there is slice information that can be accessed in Allowed NSSAI (S-NSSAI), then in step 511, the terminal selects the PLMN as a VPLMN and performs a registration process for the VPLMN. This process uses allowed NSSAI (S-NSSAI) information and can be understood as a procedure in which the terminal transmits a registration request message.

[0106] On the other hand, if there is no slice information that the terminal can access in the allowed NSSAI (S-NSSAI) when the terminal considers the PLMN information and the slice information, in step 521, the terminal determines whether possible slice aware PLMN-NSSAI (S-NSSAI) information has been received in the process of receiving the PLMN information and the slice information.

[0107] If possible slice aware PLMN-NSSAI (S-NSSAI) information is received, the terminal performs a registration request in step 523. The terminal can select a new PLMN as a VPLMN using the received possible slice aware PLMN-NSSAI (S-NSSAI) information element and transmit a registration request message to the VPLMN.

[0108] If possible slice aware PLMN-NSSAI (S-NSSAI) information is not received, the terminal does not perform the registration process in step 525.

[0109] FIG. 6 is a diagram showing the configuration of a terminal according to one embodiment of the present disclosure.

[0110] As illustrated in FIG. 6, the terminal of the present disclosure may include a transceiver (610), a memory (620), and a processor (630). The processor (630), the transceiver (610), and the memory (620) of the terminal may operate according to the communication method of the terminal described above. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the processor (630), the transceiver (610), and the memory (620) may be implemented in the form of a single chip.

[0111] The transceiver (610) is a general term for the terminal's receiving unit and the terminal's transmitting unit, and can transmit and receive signals with a base station or a network entity. The signals transmitted and received with the base station may include control information and data. To this end, the transceiver (610) may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts the received signal. However, this is only one embodiment of the transceiver (610), and the components of the transceiver (610) are not limited to the RF transmitter and RF receiver.

[0112] In addition, the transceiver (610) may include wired and wireless transceivers, and may include various configurations for transmitting and receiving signals. In addition, the transceiver (610) may receive a signal through a wireless channel, output it to the processor (630), and transmit the signal output from the processor (630) through the wireless channel. In addition, the transceiver (610) may receive a communication signal, output it to the processor, and transmit the signal output from the processor to a network entity through a wired or wireless network.

[0113] The memory (620) can store programs and data necessary for the operation of the terminal. In addition, the memory (620) can store control information or data included in signals acquired from the terminal. The memory (620) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD.

[0114] The processor (630) can control a series of processes so that the terminal can operate according to the embodiments of the present disclosure described above. The processor (630) may be collectively referred to as a control unit. For example, the processor (630) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0115] FIG. 7 is a diagram showing the configuration of a base station according to one embodiment of the present disclosure.

[0116] As illustrated in FIG. 7, the base station of the present disclosure may include a transceiver (710), a memory (720), and a processor (730). The processor (730), the transceiver (710), and the memory (720) of the base station may operate according to the communication method of the base station described above. However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components than the components described above. In addition, the processor (730), the transceiver (710), and the memory (720) may be implemented in the form of a single chip.

[0117] The transceiver (710) is a general term for the base station's receiver and transmitter, and can transmit and receive signals with a terminal or network entity. At this time, the transmitted and received signals may include control information and data. To this end, the transceiver (710) may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-downconverts the received signal. However, this is only one embodiment of the transceiver (710), and the components of the transceiver (710) are not limited to the RF transmitter and RF receiver. The transceiver (710) may include wired and wireless transceivers, and may include various configurations for transmitting and receiving signals.

[0118] In addition, the transceiver (710) can receive a signal through a communication channel (e.g., a wireless channel) and output it to the processor (730), and transmit the signal output from the processor (730) through the communication channel. In addition, the transceiver (710) can receive a communication signal and output it to the processor, and transmit the signal output from the processor to a terminal or network entity through a wired or wireless network.

[0119] The memory (720) can store programs and data required for the operation of the base station. In addition, the memory (720) can store control information or data included in signals acquired from the base station. The memory (720) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD.

[0120] The processor (730) can control a series of processes so that the base station can operate according to the embodiments of the present disclosure described above. The processor (730) may be collectively referred to as a control unit. The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0121] FIG. 8 is a diagram illustrating a configuration of a network entity according to an embodiment of the present disclosure. As illustrated in FIG. 8, the network entity of the present disclosure may include a transceiver (810), a memory (820), and a processor (830). The processor (830), the transceiver (810), and the memory (820) of the network entity may operate according to the communication method of the network entity described above. However, the components of the network entity are not limited to the examples described above. For example, the network entity may include more or fewer components than the components described above. In addition, the processor (830), the transceiver (810), and the memory (820) may be implemented in the form of a single chip. The network entity may include network functions (NFs) such as the AMF, SMF, PCF, NEF (Network Exposure Function), UDM, and UPF described above.

[0122] The transceiver (810) is a general term for the receiving unit and the transmitting unit of a network entity, and can transmit and receive signals with a terminal or another network entity. At this time, the transmitted and received signals may include control information and data. To this end, the transceiver (810) may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts the received signal. However, this is only one embodiment of the transceiver (810), and the components of the transceiver (810) are not limited to the RF transmitter and RF receiver. The transceiver (810) may include a wired transceiver and may include various configurations for transmitting and receiving signals. In addition, the transceiver (810) may receive a signal through a communication channel (e.g., a wireless channel), output it to the processor (830), and transmit the signal output from the processor (830) through the communication channel. In addition, the transceiver (810) can receive a communication signal and output it to the processor, and transmit the signal output from the processor to a terminal or other network entity via a wired or wireless network.

[0123] The memory (820) can store programs and data necessary for the operation of the network entity. Furthermore, the memory (820) can store control information or data included in signals acquired from the network entity. The memory (820) can be configured as a storage medium, such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media.

[0124] The processor (830) may control a series of processes to enable a network entity to operate according to the embodiments of the present disclosure described above. The processor (830) may be collectively referred to as a control unit. The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0125] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0126] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0127] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0128] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0129] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0130] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

[0131] Additionally, the methods described in FIGS. 1 through 5 of the present disclosure may include methods in which at least one drawing is combined, depending on various implementations. For example, FIGS. 1 through 5 may be combined (performed) to form a single flow. Furthermore, part or all of one embodiment of the present disclosure may be performed in combination with part or all of one or more other embodiments. The present disclosure may include methods in which at least one drawing is combined, depending on various implementations.

Claims

1. A method performed by a terminal of a wireless communication system, A step of receiving information for selecting a network slice from a PCF (policy control function) entity; A step of identifying whether information about a network slice to which the terminal can connect is included in the allowed NSSAI (network slice selection assistance information) based on the information for selecting the above network slice; and A method comprising the step of transmitting a registration request message to a first AMF (access and mobility management function) entity based on information about available network slices, if information about a network slice to which the terminal can connect is not included in the allowed NSSAI.

2. In paragraph 1, the method, A method further comprising the step of transmitting a registration request message to a second AMF entity based on the allowed NSSAI, if information about a network slice to which the terminal can connect is included in the allowed NSSAI.

3. In paragraph 1, A method, wherein the information for selecting the network slice includes at least one of information about at least one public land mobile network (PLMN) or information about the available network slice supported by the at least one PLMN.

4. In paragraph 3, The above PCF entity is included in the HPLMN (home PLMN), At least one of the PLMNs is a VPLMN (visited PLMN), A method, wherein said at least one PLMN comprises a first PLMN associated with the first AMF entity and a second PLMN associated with the second AMF entity.

5. A method performed by a PCF (policy control function) entity of a wireless communication system, A step of transmitting information for selecting a network slice to a terminal, Whether information about the network slice to which the above terminal can connect is included in the allowed NSSAI (network slice selection assistance information) is based on the information for selecting the above network slice. A method wherein, if information about a network slice to which the above terminal can connect is not included in the allowed NSSAI, a registration request message to the first AMF (access and mobility management function) entity is based on information about an available network slice.

6. In paragraph 5, A method, wherein if information about a network slice to which the terminal can connect is included in the allowed NSSAI, a registration request message to the second AMF entity is based on the allowed NSSAI.

7. In paragraph 5, A method, wherein the information for selecting the network slice includes at least one of information about at least one public land mobile network (PLMN) or information about the available network slice supported by the at least one PLMN.

8. In paragraph 7, The above PCF entity is included in the HPLMN (home PLMN), At least one of the PLMNs is a VPLMN (visited PLMN), A method, wherein said at least one PLMN comprises a first PLMN associated with the first AMF entity and a second PLMN associated with the second AMF entity.

9. In the terminal of a wireless communication system, Transmitter and receiver; and At least one control unit connected to the above transceiver unit, At least one of the above control units: Receive information for selecting a network slice from a PCF (policy control function) entity, Based on the information for selecting the above network slice, identify whether information on a network slice to which the terminal can connect is included in the allowed NSSAI (network slice selection assistance information), and A terminal configured to transmit a registration request message to a first AMF (access and mobility management function) entity based on information about available network slices, if information about a network slice to which the terminal can connect is not included in the allowed NSSAI.

10. In paragraph 9, at least one control unit, A terminal further configured to transmit a registration request message to a second AMF entity based on the allowed NSSAI, if information about a network slice to which the terminal can connect is included in the allowed NSSAI.

11. In paragraph 9, A terminal, wherein the information for selecting the above network slice includes at least one of information about at least one public land mobile network (PLMN) or information about the available network slice supported by the at least one PLMN.

12. In paragraph 11, The above PCF entity is included in the HPLMN (home PLMN), At least one of the PLMNs is a VPLMN (visited PLMN), A terminal, wherein said at least one PLMN comprises a first PLMN associated with the first AMF entity and a second PLMN associated with the second AMF entity.

13. In the PCF (policy control function) entity of a wireless communication system, Transmitter and receiver; and At least one control unit connected to the above transceiver unit, At least one of the above control units: Transmit information for selecting a network slice to the terminal, Whether information about the network slice to which the above terminal can connect is included in the allowed NSSAI (network slice selection assistance information) is based on the information for selecting the above network slice. A PCF entity, wherein a registration request message to the first AMF (access and mobility management function) entity is based on information about available network slices, if information about the network slices to which the above terminal can connect is not included in the allowed NSSAI.

14. In paragraph 13, A PCF entity, wherein the registration request message to the second AMF entity is based on the allowed NSSAI, if information about the network slice to which the above terminal can connect is included in the above allowed NSSAI.

15. In paragraph 13, A PCF entity, wherein the information for selecting the above network slice includes at least one of information about at least one public land mobile network (PLMN) or information about the available network slice supported by the at least one PLMN.

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