Method and apparatus for selecting AMF for terminal network registration

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate beyond a 4G communication system such as LTE. An operation method of a base station according to an embodiment of the present invention may comprise the steps of: receiving, from a terminal, a request message for network registration; transmitting, to a network repository function (NRF), an access and mobility management function (AMF) search request message on the basis of the request message; receiving a plurality of pieces of AMF profile information from the NRF; and selecting an AMF on the basis of the request message and the plurality of pieces of AMF profile information.

Description

Method and device for selecting an AMF for terminal network registration

[0001] The present disclosure relates to operations between a base station and a core network in a wireless communication system. More specifically, it relates to a method and apparatus for a base station to search for and select a network device for terminal registration when a terminal registers with a network to use network services.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th-generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th-generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are referred to as "Beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps, and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., the 95 GHz to 3 terahertz (3 THz) band). In the terahertz band, due to more severe path loss and atmospheric absorption compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technology capable of guaranteeing signal reach, or coverage, is expected to increase. As key technologies to ensure coverage, radio frequency (RF) devices, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multi-antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (high-altitude platform stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (artificial intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] The present disclosure is intended to improve the control signaling transmission and reception procedure for terminal network registration between a base station and a core network. The technical problems to be solved by the present disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0008] A method of operation of a base station in a wireless communication system according to an embodiment of the present invention may include: receiving a request message for network registration from a terminal; transmitting an access and mobility management function (AMF) search request message to a network repository function (NRF) based on the request message; receiving a plurality of AMF profile information from the NRF; and selecting an AMF based on the request message and the plurality of AMF profile information.

[0009] The method of the base station may further include the step of transmitting a non-access stratum (NAS) message for initial connection of the terminal to the selected AMF; and the step of receiving a downlink NAS message from the AMF.

[0010] The above registration request message may include requested network slice selection assistance information (NSSAI) and registration type information.

[0011] The above registration type information can be set to one of the following values: initial registration, mobility registration renewal, periodic registration renewal, emergency registration, disaster roaming initial registration, or disaster roaming mobility registration renewal.

[0012] If a valid GUTI (globally unique temporary identifier) ​​of the terminal exists, the GUTI is included in the registration request message, and if a valid GUTI of the terminal does not exist within the terminal, a SUCI (Subscription Concealed Identifier) ​​may be included in the registration request message.

[0013] The above AMF search request message may include NSSAI (requested network slice selection assistance information) requested by the terminal, TAC (tracking area code) and PLMN (public land mobile network) ID managed by the searched AMF.

[0014] In a wireless communication system according to one embodiment of the present invention, the operation of a terminal may include: transmitting a request message for network registration to a base station; receiving an identifier request message from an AMF selected by the base station via a network repository function (NRF) based on the request message; transmitting an identifier response message containing the identifier of the terminal to the AMF; and receiving a registration acceptance message from the AMF.

[0015] The method of the above terminal may further include the step of including the GUTI (globally unique temporary identifier) ​​in the registration request message if the valid GUTI of the terminal exists; and the step of including the SUCI (Subscription Concealed Identifier) ​​in the registration request message if the valid GUTI of the terminal does not exist within the terminal.

[0016] One embodiment of the present disclosure provides an apparatus and method in which a base station in a wireless communication system can effectively perform an AMF selection for a terminal's network registration request by utilizing an SBI interface.

[0017] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0018] FIG. 1 is a diagram illustrating the structure of a current 5G wireless communication system according to various embodiments of the present disclosure.

[0019] FIG. 2 illustrates the deployment of a RAN and 5GC to which O-RAN (Open RAN) is applied according to one embodiment of the present disclosure.

[0020] FIG. 3 illustrates an example of a deployment scenario for RAN and AMF according to one embodiment of the present disclosure.

[0021] FIG. 4 illustrates an N2 interface and communication protocol stack between (R)AN and 5GC according to one embodiment of the present disclosure.

[0022] FIG. 5 illustrates a setup procedure for using an NG-C interface after a TNL association between an NG-RAN and an AMF is established according to one embodiment of the present disclosure.

[0023] FIG. 6 illustrates an E-SBA (Evolved SBA) network structure based on a 5GS (5G System) structure with an N2 interface based on an SBI (Service-Based Interface) according to one embodiment of the present disclosure.

[0024] FIGS. 7a and 7b are drawings illustrating a network registration procedure of a conventional terminal according to one embodiment of the present disclosure.

[0025] FIG. 8 is a diagram illustrating a network registration procedure for a terminal in a network structure to which an SBI-based N2 interface is applied according to one embodiment of the present disclosure.

[0026] Figure 9 illustrates the AMF search and selection procedure of NG-RAN using NRF.

[0027] FIG. 10 is a block diagram of a terminal or user equipment according to one embodiment of the present disclosure.

[0028] FIG. 11 is a block diagram of a base station according to one embodiment of the present disclosure.

[0029] FIG. 12 is a block diagram of a network entity performing network functions according to one embodiment of the present disclosure.

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0031] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0032] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual dimensions. Identical or corresponding components in each drawing have been assigned the same or different reference numbers.

[0033] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the 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. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0034] In the present disclosure, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams may be performed based on computer program instructions. Since these computer program instructions may be optionally loaded into at least one processor of a general-purpose computer, a computer for special purposes, or other programmable data processing equipment, the instructions performed through any one or any combination of at least one processor of the computer or other programmable data processing equipment create means for performing the functions described in the flow diagram block(s). Since these computer program instructions may also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the functions in a specific manner, the instructions stored in computer-available or computer-readable memory may also produce a manufactured item containing means of instruction for performing the functions described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0035] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks (or functions) described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to the corresponding function.

[0036] As used in the embodiments of the present disclosure, the term “part” refers to a software or hardware component, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), and the “part” performs certain roles. However, the term including “part” is not limited to software or hardware. The “part” may be configured to reside in an addressable storage medium or may be configured to run on one or more processors. Thus, by example, the “part” includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, 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.” In addition, the components and 'parts' may be implemented to utilize one or more CPUs (central processing units) within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0037] As stated above, it should be noted that the blocks of each flowchart and combinations of flowcharts described in this disclosure may be executed by one or more computer programs including instructions. The entirety of one or more computer programs may be stored in a single memory device, or one or more computer programs may be divided into different parts and stored across multiple memory devices.

[0038] Additionally, any / any function or operation described in this disclosure may be processed by a single processor or a combination of processors. The single processor or combination of processors is a circuitry that performs processing and may include an application processor (AP, e.g., a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural network processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near-field communication (NFC) chip, a connectivity chip, a sensor controller, a touch controller, a fingerprint sensor controller, a display driver integrated circuit (IC), an audio codec (CODEC) chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, a microprocessor unit (MPU), a system-on-chip (SoC), an IC, or similar circuitry.

[0039] Additionally, it should be noted that various embodiments in the claims and description of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0040] Such software may be stored on a non-transitory computer-readable storage medium. A non-transitory computer-readable storage medium stores one or more computer programs (software modules), and said one or more computer programs include computer-executable instructions that operate an electronic device to perform a method according to the present disclosure when executed alone or collectively by one or more processors of an electronic device.

[0041] The software may be stored in a transient or non-transient storage device, for example, in the form of read-only memory (ROM) (whether or not it is erasable or rewritable), or random access memory (RAM), memory chips, devices, or integrated circuits (ICs). Additionally, the software may be stored in the form of an optically or magnetically readable medium, for example, a compact disc (CD), a digital multifunction disc (DVD), a magnetic disc, or a magnetic tape. It should be understood that the storage device and the storage medium are examples of non-transient machine-readable storage media suitable for storing programs for implementing various embodiments of the present disclosure. Accordingly, various embodiments of the present disclosure may provide a program containing code for implementing a device or method according to any one of the claims of this specification, and a non-transient machine-readable storage medium storing such program.

[0042] In the following disclosure, determining the priority between A and B may be referred to in various ways, such as selecting the one with the higher priority according to a predetermined priority rule and performing the corresponding action, or omitting or dropping the action for the one with the lower priority.

[0043] Hereinafter, 'A or B' as described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0044] Additionally, 'at least one of A, B, and C' described in the present disclosure may be understood to include 'A', or 'B', or 'C', or 'any combination of A, B, and C'.

[0045] Additionally, 'at least one of A, B, or C' described in the present disclosure may be understood to include 'A', or 'B', or 'C', or 'any combination of A, B, and C'.

[0046] Additionally, 'A / B' as described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0047] Additionally, 'A, B' described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0048] Additionally, 'A and B' described in the present disclosure may be understood as 'A and / or B', which may be understood as including 'A', or 'B', or 'A and B'.

[0049] Furthermore, the phrase "when conditions A and B are satisfied" as described in the present disclosure is not necessarily limited to cases where both conditions A and B are satisfied, but may be understood to include cases where either condition A or condition B is satisfied individually, cases where both conditions A and B are satisfied, or cases where one or more additional conditions are satisfied together.

[0050] Furthermore, throughout this specification, ordinal terms (and similar modifiers) such as 'first', 'second', 'third', etc. are used solely for the purpose of distinguishing various instances, occurrences, configurations, messages, stages, or aspects of elements, operations, or information, as described below. Unless clearly required otherwise by the context, the use of such ordinal terms does not require that the elements, operations, or information distinguished by such terms be structurally different, numerically distinct, or essentially different. For example, 'first signal' and 'second signal' may represent instances of the same signal transmitted at different times, signals containing the same core information even with some variations, or signals having different content or characteristics depending on the specific context. Similarly, 'first value' and 'second value' may represent the same magnitude measured or applied in different situations, or may represent different magnitudes. Such interpretation must be determined based on the specific technical context, function, and relationship described in the relevant parts of the specification and claims.

[0051] Furthermore, although terms such as "first," "second," etc., as used in this disclosure are used for various elements such as information, objects, actions, and sequences, they are not intended to limit such elements to a specific order. These terms may be understood merely as distinguishing one element from another. For example, a first element may be referred to as a second element, and likewise, a second element may be referred to as a first element.

[0052] Additionally, the terms 'first' and 'second' described in this disclosure may be understood to refer to identical or different elements. For example, if an element is information, the first information and the second information may both be information, and depending on the case, they may be the same information or different information.

[0053] Furthermore, the expressions 'if' and 'in case that' described in this disclosure or claims may be interpreted, depending on the context, as meaning 'when or upon,' 'in response to,' 'based on,' or 'according to,' and these expressions may be used interchangeably. In addition, other expressions having substantially the same meaning may be used as substitutes, provided that they do not impair the technical features of this disclosure.

[0054] Additionally, the term "not perform" as used in this disclosure or claims may be understood, depending on the context, to mean to omit or skip the corresponding step. Such a term may be replaced with other terms having the same or substantially similar meaning.

[0055] Additionally, the phrase "transmitting a message containing A and B" as described in this specification may be interpreted to include not only (i) cases where A and B are transmitted as a single message, but also (ii) cases where A and B are transmitted individually through multiple messages (e.g., transmitting a first message containing A and a second message containing B). This interpretation may also apply to cases where messages containing two or more items, such as A, B, and C, are transmitted together or individually.

[0056] In addition, 'transmitting a message containing A and transmitting a message containing B' can also be interpreted as transmitting a single message containing A and B.

[0057] In the specific embodiments of the present disclosure described below, terms or components included in the disclosure will be expressed in the singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the circumstances presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed in the singular form, and even if a component is expressed in the singular form, it may be composed in the plural form.

[0058] The drawings or flowcharts described below illustrate exemplary methods that may be implemented in accordance with the principles of the present disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the present disclosure. For example, although illustrated as a series of steps, the various steps of each drawing or flowchart may overlap, occur in parallel, occur in a different order, or occur multiple times. In other examples, any step may be omitted or replaced with another step.

[0059] The methods and devices proposed in the embodiments of the present disclosure below are not limited to each embodiment and may be utilized as a combination of all or part of the embodiments proposed in the disclosure. Accordingly, the embodiments of the present disclosure may be applied with some modifications within the scope that does not deviate significantly from the scope of the present disclosure, at the judgment of a person skilled in the art.

[0060] In this case, any wording mentioned in different embodiments may be used interchangeably, combined, or substituted if the concepts correspond. For example, regarding the same or corresponding concepts, even if the expression 'A' is used in one embodiment and the expression 'B' is used in another embodiment, they may be understood by interchangeably, substituted, or combined.

[0061] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used. Furthermore, where appropriate, such terms may be replaced with terms defined in the 3GPP (3rd generation partnership project) Technical Specifications (TS).

[0062] Hereinafter, the base station, as the entity performing resource allocation for terminals, may be at least one of gNode B, eNode B, Node B, BS (base station), wireless access unit, base station controller, or a node on a network. Additionally, the base station of the present disclosure may include a structure split into a central unit (CU) and a distributed unit (DU). In such a structure, the CU is responsible for the upper layer of the control and user plane, and the DU is responsible for wireless resource processing of the lower layer. The embodiments of the present disclosure can be equally applied to a 5G base station structure in which functions are separated into the CU and DU as described above.

[0063] The terminal may include a UE (user equipment), MS (mobile station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions.

[0064] In the present disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station.

[0065] In addition, while a 5th generation mobile communication system (5G, new radio, NR) and a 6th generation mobile communication system (6G) may be described below as examples, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, new advanced mobile communication systems developed after 5G and 6G may be included therein. Furthermore, the present disclosure may be applied to other communication systems (e.g., Wi-Fi systems) with some modifications made in the judgment of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0066] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0067] In describing the present disclosure below, the term "upper layer signaling" may be a signaling corresponding to at least one or a combination of at least one of MIB (master information block), SIB (system information block), SIB M (M=1, 2, ⪋), RRC (radio resource control), MAC (medium access control), CE (control element), NAS (non-access stratum) signaling, or application layer messages. The RRC signaling may also be referred to as L3 signaling (layer 3 signaling).

[0068] Additionally, L1 signaling may be a signaling method corresponding to at least one or a combination of at least one of the following: a physical layer channel or signaling of a PDCCH (physical downlink control channel), a DCI (downlink control information), a UE-specific DCI, a group common DCI, a common DCI, a scheduling DCI (e.g., a DCI used for the purpose of scheduling downlink or uplink data), a non-scheduling DCI (e.g., a DCI not used for the purpose of scheduling downlink or uplink data), a PUCCH (physical uplink control channel), or an UCI (uplink control information). The above L1 signaling may also be referred to as physical layer signaling.

[0069] Hereinafter, the expression in the present disclosure or claims that information can be configured from a base station may mean that, depending on the context, a terminal receives said information from a base station through physical layer signaling or upper layer signaling, and such expression may be replaced with other terms having the same or substantially similar meaning.

[0070] The operating principle of the present disclosure will be explained in detail below with reference to the attached drawings.

[0071] FIG. 1 is a diagram illustrating the structure of a wireless communication system according to various embodiments of the present disclosure. More specifically, FIG. 1 illustrates an example of the configuration of a 5G system. Referring to FIG. 1, a 5G network may include at least one of the network entities (NE) or network functions (NF) described below. Since the structure of a 6G wireless communication system has not yet been defined, the description of 6G technology in the present disclosure may be based on the structure of a 5G wireless communication system. Because the NE or NF described in the present disclosure is described based on the structure of a 5G wireless system, different terms or names may be used in future 6G wireless communication systems. Accordingly, the terms and names used in the present disclosure are not limited to 5G wireless communication systems but may be equally applicable to other standards (e.g., 6G wireless communication systems).

[0072] According to one embodiment, the (R)AN ((Radio) Access Network) (102) is an entity that performs wireless resource allocation for terminals and may include at least one of eNode B, Node B, BS (Base Station), NG-RAN (Next Generation Radio Access Network), 5G-AN (5G Access Network), 5G NR (5G New Radio), a wireless access unit, a base station controller, or a node on the network.

[0073] According to one embodiment, the terminal (101) may include a User Equipment (UE), Next Generation UE (NG UE), Mobile Station (MS), cellular phone, smartphone, computer, Internet of Things (IoT) device, or a multimedia system capable of performing communication functions.

[0074] In addition, although embodiments of the present disclosure are described below using a 5G system as an example, embodiments of the present disclosure may be applied to other communication systems having a similar technical background. Furthermore, embodiments of the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0075] As wireless communication systems evolve from 4G systems to 5G systems, a new core network (CN), called the Next Generation Core (NG Core) or 5G Core Network (5GC), has been defined. The new core network can virtualize all existing network entities (NE) to create network functions (NF). According to one embodiment of the present disclosure, a network function may refer to a network entity, a network component, or a network resource.

[0076] According to one embodiment of the present disclosure, 5GC may include one or more NFs illustrated in FIG. 1. Of course, it is not limited to the example of FIG. 1, and 5GC may include a greater number of NFs than the NFs illustrated in FIG. 1 or a smaller number of NFs.

[0077] According to one embodiment, the Access and Mobility Management Function (AMF) (103) may be a network function that manages the access and mobility of a terminal (UE). For example, the AMF (103) may perform network functions such as registration, connection, reachability, mobility management, access verification, authentication, and the generation of mobility events.

[0078] According to one embodiment, the Session Management Function (SMF) (105) may be a network function that manages Packet Data Network (PDN) connections provided to a User Terminal (UE). The PDN connection may be referred to as a Protocol Data Unit (PDU) Session. For example, the SMF (105) may perform network functions such as session management functions through the establishment, modification, and release of sessions and the maintenance of tunnels between the User Plane Function (UPF) (104) and the RAN required for this, selection and control of User Planes (UP), control of traffic processing in the UPF, and control of billing data collection.

[0079] According to one embodiment, the PCF (Policy Control Function) (106) may be a network function that applies a mobile carrier's service policy, billing policy, and policy for a PDU Session to a terminal.

[0080] According to one embodiment, the Unified Data Management (UDM) (109) may be a network function that stores information about a subscriber. For example, the UDM (109) may perform functions such as generating authentication information for 3GPP security, processing user identifiers (User IDs), managing a list of network functions that support the UE, and managing subscription information.

[0081] According to one embodiment, the Network Exposure Function (111) may be a function that provides information about a terminal to a server outside the 5G network. Additionally, the NEF (111) may provide information necessary for service to the 5G network and store it in the Unified Data Repository (UDR).

[0082] According to one embodiment, the User Plane Function (UPF) (104) may be a function that performs the role of a gateway to transmit user data (e.g., PDU) to the Data Network (DN) (110). More specifically, the UPF (104) may perform the role of processing data so that data transmitted by a terminal can be transmitted to an external network or data received from an external network can be transmitted to the terminal. As an example, the UPF (104) may perform network functions such as acting as an anchor between Radio Access Technologies (RATs), packet routing and forwarding, packet inspection, application of user plane policies, generation of traffic usage reports, and buffering.

[0083] According to one embodiment, the Network Repository Function (NRF) (115) can perform the function of storing profiles of NFs and discovering NFs.

[0084] According to one embodiment, the AUSF (Authentication Server Function) (108) can perform terminal authentication in a 3GPP access network and a non-3GPP access network.

[0085] According to one embodiment, the Network Slice Selection Function (NSSF) (114) can perform the function of selecting a Network Slice Instance provided to the terminal.

[0086] According to one embodiment, the Network Data Analytics Function (NWDAF) (113) can collect data from multiple NF(s) for the purpose of efficient operation of the 5GC network. According to one embodiment, the collected data can be analyzed using a Machine Learning (ML) model, and the results of the analysis can be provided back to the NFs to help each NF provide efficient network services.

[0087] According to one embodiment, an Application Function (AF) (107) can communicate with a network provider so that an external server (Application Server) can use network services provided by the network provider. The AF (107) can be classified into an internal AF and an external AF depending on the deploying entity. An internal AF deployed by a network operator can communicate directly with NFs within the network provider. An external AF deployed by a third-party service provider may need to pass through an NEF (111) to communicate with internal NFs within the network provider.

[0088] According to one embodiment, the DN (Data Network) (110) may be a data network through which a terminal transmits and receives data in order to use the network operator's service or a third party service.

[0089] According to one embodiment, the Network Slice Admission Control Function (NSACF) (116) can limit the number of PDU sessions of registered terminals in each slice and thereby perform the function of managing resources.

[0090] According to one embodiment, the Network Slice-Specific Authentication and Authorization Function (NSSAAF) (112) can create a slice authentication context for a terminal and perform slice-specific authentication and authorization procedures.

[0091] According to one embodiment, the Edge Application Server Discovery Function (EASDF) (117) can create a domain name system (DNS) context for a PDU session and can perform the function of storing UE IP (internet protocol) addresses, DNS message processing rules, etc. in the context.

[0092] According to one embodiment, the SCP (Service Communication Proxy) (118) can perform indirect communication functions such as searching for services and responding to calls.

[0093] According to one embodiment, the terminal (101) may include an IoT device. The IoT device may include a device that does not use battery power or operates with very little power, and such an IoT device may be referred to as an ambient IoT device (or ambient IoT).

[0094] In 3GPP systems, a conceptual link connecting NFs within a 5G system is defined as a Reference Point. The following is an example of a Reference Point included in the 5G system architecture depicted in Figure 1.

[0095] - N1: Reference point between UE and AMF

[0096] - N2: Reference point between (R)AN and AMF

[0097] - N3: Reference point between (R)AN and UPF

[0098] - N4: Reference point between SMF and UPF

[0099] - N6: Reference point between UPF and DN

[0100] - N9: Reference point between 2 core UPFs

[0101] In addition, in 3GPP systems, the 5G system architecture may include service-based interfaces such as the following examples.

[0102] - Nnssf: Service-based interface by NSSF

[0103] - Nnssaaf: Service-based interface based on NSSAAF (Network Slice-Specific Authentication and Authorization Function)

[0104] - Nnef: Service-based interface by NEF

[0105] - Nausf: Service-based interface by AUSF

[0106] - Nnrf: Service-based interface by NRF

[0107] - Namf: Service-based interface by AMF

[0108] - Npcf: Service-based interface by PCF

[0109] - Nsmf: Service-based interface by SMF

[0110] - Nupf: Service-based interface by UPF

[0111] - Nudm: Service-based interface by UDM

[0112] - Naf: Service-based interface by AF

[0113] - Nasaf: Service-based interface by AUSF

[0114] - Neasdf: Service-based interface by EASDF (Edge Application Server Discovery Function)

[0115] - Nnwdaf: Service-based interface by NWDAF

[0116] In this disclosure, an Evolved Service-Based Architecture (E-SBA) structure is proposed as a 6G network structure for a 6GS (6G System). The E-SBA structure is a network structure improved to be suitable for a 6G network structure based on the SBA structure, which is a 5G network structure. In particular, in the case of a conventional SBA network structure, the N2 interface connecting the NG-RAN (NG Radio Access Network) and the 5GC (5G Core Network) is a Point-to-Point (P2P) based interface. The fact that the N2 interface is a P2P based interface has increased the complexity of the 5G network structure and has additionally caused various problems associated with the use of the P2P based interface.

[0117] In this disclosure, an E-SBA network structure is proposed in which the N2 interface of a conventional SBA network structure is replaced with an SBI-based interface as a 6G network structure, and a 6G network structure-based control signaling procedure is proposed to provide network services to a user.

[0118] More specifically, the present disclosure proposes an SBI-based N2 interface-based AMF selection procedure in an E-SBA structure that replaces the conventional NG-AP (Next Generation Application Protocol) interface-based NG-RAN AMF selection procedure when a terminal network registration procedure is performed for a user to receive network services.

[0119] FIG. 2 illustrates the deployment of a RAN and 5GC to which O-RAN (Open RAN) is applied according to one embodiment of the present disclosure.

[0120] A RAN (Radio Access Network) can be composed of a CU (Central Unit) (230), a DU (Distributed Unit) (220), and an AAU (Active Antenna Unit) (210). The AAU (210) includes an RF (Radio Frequency) antenna and can generally be implemented in hardware (Hardware, H / W) to perform direct wireless communication with user terminals. For wireless communication with user terminals, the AAU (210) may include an RF layer and a PHY-LOW layer as part of its communication protocol stack. Since areas where wireless communication through the AAU (210) does not reach become communication dead zones, the AAU (210) must be densely deployed across the entire region. To cover an entire country without communication dead zones, the operation of a large number of AAU (210) devices is required; therefore, the highest cost when deploying a communication system may be incurred in the installation and operation of the AAU (210) devices.

[0121] The DU (220) and the AAU (210) are connected via a fronthaul. In O-RAN, the fronthaul is standardized as an eCPRI (enhanced Common Public Radio Interface) interface. The DU (220) may include a communication protocol stack consisting of a PHY-HIGH layer for processing radio signals received from the AAU (210), a MAC (Multiple Access Control) layer for multiplexing and scheduling multiple data, and an RLC (Radio Link Control) layer for acknowledging transmitted and received data.

[0122] The CU (230) and DU (220) are connected via a midhaul. The CU (230) may include a dual protocol stack. If the CU (230) includes a dual protocol stack, the dual protocol stack may include a protocol stack responsible for the Uu interface and a protocol stack responsible for the N2 interface.

[0123] The stack responsible for the Uu interface can be composed of the following layers: the PDCP (Packet Data Convergence Protocol) layer, which is responsible for IP header compression, user data transmission, and sequence numbers for the Radio Bearer, and the RRC (Radio Resource Control) layer, which is responsible for controlling radio resources.

[0124] The N2 interface is responsible for exchanging control signals between the RAN and the 5GC and may be composed of the following layers: a physical layer that converts data to be exchanged between the CU and the 5GCN into electrical and optical signals for transmission and reception; a data link layer that is responsible for data transmission between two devices and performs error detection and control functions; an IP (Internet Protocol) layer that determines the path to deliver data to a destination based on IP addresses; a SCTP (Stream Control Transmission Protocol) layer that manages data transmission and performs error detection, recovery, and flow control; and an NG-AP (NG Application Protocol) layer that is responsible for managing the N2 interface and terminal-related control signals. According to one embodiment, the physical layer and the data link layer may be separated into a Radio Network Layer (RNL) layer, and the IP layer and the SCTP layer may be separated into a Transport Network Layer (TNL) layer.

[0125] In the case of the AAU (210), which includes the antenna, which is hardware, it is impossible to implement it in software, but the DU (220) and CU (230), excluding the AAU (210), can be implemented in software using the IT technology Virtual Network Function (VNF) technology. Since implementing the DU (220) and CU (230) with dedicated hardware equipment is expensive, an increasing number of network operators are implementing the DU (220) and CU (230) equipment on their own cloud equipment or commercial cloud equipment by virtualizing them to be cloud-native in order to reduce costs.

[0126] FIG. 3 illustrates an example of a deployment scenario for RAN and AMF according to one embodiment of the present disclosure.

[0127] In FIG. 3, the illustration and description of other technologies and equipment, including O-RAN technology, have been omitted in order to accurately and concisely explain the gist of the deployment scenario embodiment. This means that the embodiment is not limited to the deployment scenario illustrated in the present disclosure and can be applied to various forms of deployment scenarios in which other technologies and equipment are added.

[0128] A single base station can be responsible for multiple cells, and these cells can be formed to span multiple Tracking Areas (TAs). In FIG. 3, it can be assumed that the cells responsible for the base station are spread across TA2 (340) and TA3 (350). This means that the AMF responsible for TA2 (340) and TA3 (350) manages the base station. In the embodiment of FIG. 3, it can be assumed that AMF #1 (310) and AMF #2 (320) manage TA2 (340) and TA3 (350).

[0129] That is, the base station can establish a connection to use the N2 interface with AMF #1 (310) and AMF #2 (320) to transmit and receive control signals in relation to 5GC, and can use this connection to exchange base station configuration information, N2 interface related management information, and terminal control signals.

[0130] FIG. 4 illustrates an N2 interface and communication protocol stack between (R)AN and 5GC according to one embodiment of the present disclosure.

[0131] The N2 interface is an interface connecting the (R)AN and the 5GC. In practice, it is used to transmit control signals between the CU of the (R)AN (410) and the AMF (420) of the 5GC. The N2 interface is a point-to-point (P2P) based interface that connects only two devices (CU and AMF). Devices using a P2P based interface may not easily add new features or upgrade devices due to the high functional dependency between devices. Additionally, adding new features or upgrading devices may cause changes to the interface itself.

[0132] The communication protocol stack constituting the N2 interface can be composed of the physical layer (L1 layer), the link layer (L2 layer), the IP (Internet Protocol) layer, the SCTP (Stream Control Transmission Protocol) layer, and the NG-AP (NG Application Protocol) layer. The L1 layer and the L2 layer can be classified as the Radio Network Layer (RNL), and the IP layer and the SCTP layer can be classified as the Transport Network Layer (TNL).

[0133] In order for the RAN (410) and AMF (420) to transmit and receive control data, TNL associations must be established between the two devices. When the RAN device starts operating, the connection establishment procedure for the TNL association can be initiated by the RAN device. Since the TNL association is an IP layer and SCTP layer-based connection, the RAN device must know the IP address and port number of the AMF device to initiate the connection establishment procedure. Current 3GPP standards assume that the RAN device knows the IP address and port number of the AMF devices with which it needs to establish the TNL association.

[0134] The SCTP protocol is a transport protocol designed primarily for telecommunications and signaling environments, integrating the strengths of TCP (Transport Control Protocol) and UDP (User Datagram Protocol). As the SCTP protocol is mainly used in mobile communication systems, its application is very limited. To enhance connection stability, the SCTP protocol includes a multi-homing feature. This feature establishes two SCTP connections using two IP addresses if the transmitting and receiving nodes possess two IP addresses. In practice, only one SCTP connection is used for communication: the primary SCTP connection. The other SCTP connection serves as a backup that can be immediately utilized for data communication when the currently used primary SCTP connection becomes unavailable due to physical line failures or malfunctions in equipment such as routers along the path. While the advantages of this multi-homing feature were useful in the past when communication lines were unreliable and equipment stability was low, the SCTP protocol is no longer useful today due to the very low frequency of such problems. Moreover, since network operators implement redundancy for communication lines and equipment to enhance network stability, the likelihood of problems arising from failures in communication lines and equipment is extremely low.

[0135] Multiple TNL connections may be created between the RAN (410) equipment and the AMF (420) equipment, and some of the created TNL connections may be used to transmit control signals unrelated to the terminal, while others may be used to transmit control signals related to the terminal. In particular, to transmit control signals related to the terminal, a procedure called NGAP UE-TNLA binding must be performed. This procedure maps the terminal's signaling traffic to a specific TNL connection.

[0136] FIG. 5 illustrates a setup procedure for using an NG-C interface after a TNL connection between an NG-RAN (510) and an AMF (520) is established according to one embodiment of the present disclosure.

[0137] This procedure is a procedure in which two nodes exchange information at the application level to operate the NG-C interface, which is a control plane interface between NG-RAN (510) and AMF (520). This procedure is the first NGAP (Next Generation Application Protocol) procedure performed when the TNL (Transport Network Layer) connection is established, and it is a non-UE associated signaling procedure for signaling unrelated to the terminal.

[0138] In step S501, NG-RAN (510) can send an NG SETUP REQUEST message containing its own configuration information to AMF (520).

[0139] The NG setting request message may include the information listed in Table 1 below.

[0140] IE / Group NamePresenceRangeSemantics descriptionMessage TypeM Global RAN Node IDM RAN Node NameO Supported TA List 1Supported TAs in the NG-RAN node.>Supported TA Item 1.. <maxnooftacs>>>TACM Broadcast TAC>>Broadcast PLMN List 1 >>>Broadcast PLMN Item 1.. <maxnoofbplmns>>>>>PLMN IdentityM Broadcast PLMN>>>>TAI Slice Support ListM Supported S-NSSAIs per TAC, per PLMN or per SNPN.>>>>NPN SupportO If the NID IE is included, it identifies a SNPN together with the PLMN Identity IE.>>>>Extended TAI Slice Support ListO Additional Supported S-NSSAIs per TAC, per PLMN or per SNPN.>>>>TAI NSAG Support ListO NSAG information associated with the slices per TAC, per PLMN or per SNPN.>>Configured TAC IndicationO >>RAT InformationO RAT information associated with the TAC of the indicated PLMN(s).Default Paging DRXM UE Retention InformationO NB-IoT Default Paging DRXO Extended RAN Node NameO

[0141] Upon receiving the NG setup request message in step S503, the AMF (520) can send an NG setup response message containing its own setup information to the NG-RAN (510).

[0142] The NG setting response message may include the setting information of the AMF (520) in Table 2 below.

[0143] IE / Group NamePresenceRangeSemantics descriptionMessage TypeM AMF NameM Served GUAMI List 1 >Served GUAMI Item 1.. <maxnoofservedguamis>>>GUAMIM >>Backup AMF NameO >>GUAMI TypeO Relative AMF CapacityM PLMN Support List 1 >PLMN Support Item 1.. <maxnoofplmns>>>PLMN IdentityM >>Slice Support ListM Supported S-NSSAIs per PLMN or per SNPN.>>NPN SupportO If NID IE is included, it identifies a SNPN together with the PLMN Identity IE.>>Extended Slice Support ListO Additional Supported S-NSSAIs per PLMN or per SNPN.>>Onboarding SupportO Indication of onboarding support.Criticality DiagnosticsO UE Retention InformationO IAB SupportedO Indication of support for IAB.Extended AMF NameO Mobile IAB SupportedO Indication of support for mobile IAB.

[0144] FIG. 6 illustrates an E-SBA (Evolved SBA) network structure based on a 5GS (5G System) structure with an N2 interface based on an SBI (Service-Based Interface) according to one embodiment of the present disclosure.

[0145] As the P2P (Point-to-Pont) based N2 interface connecting the existing NG-RAN (602) and AMF (603) is replaced with an SBI-based interface, the NG-RAN (602) can transmit and receive control signals to and from all NF (Network Functions) within the 5GC (5G Core Network) in addition to the AMF (603) via the SBI interface.

[0146] Conventionally, because the AMF (603) was the NAS (Non-Access Stratum) signaling termination point, all NAS control signals, including SM (Session Management), UE Policy, SMS (Short Message Service), and LCS (Location Services), in addition to MM (Mobility Management) NAS, were transmitted to the AMF (603), and the AMF (603) had to transmit these control signals to the corresponding NFs. Additionally, since the NG-RAN does not have an SBI interface, searching for and selecting NFs and NF services to use NF services, and requesting NF services from the corresponding NFs, could only be done through the AMF (603). Any tasks performed at the request of the NG-RAN (602), regardless of the AMF (603)'s inherent services, could cause an unnecessarily excessive load on the AMF (603). In addition, since all NAS control signals and all other control signals transmitted by all NG-RAN (602) managed by a single AMF (603) are transmitted to that AMF (603), the AMF (603) may experience severe control signal congestion, and if a problem occurs with the equipment due to various factors such as the hardware or software of the AMF (603), the transmission and reception of control signals between the terminal and the 5GC may be impossible, which could cause the entire 5GS system to be paralyzed.

[0147] In addition to the aforementioned problems, the conventional P2P-based N2 interface retains all the disadvantages inherent in P2P-based interfaces. The P2P interface is an interface proposed for transmitting and receiving data between two end nodes. In other words, if all NFs in a network utilize a P2P-based interface, each pair of NFs will use a separate interface, which makes the network extremely complex. Furthermore, since each distinct interface is implemented with a different protocol stack, implementing and maintaining these interfaces consumes significant resources, including time, cost, and manpower. In contrast, because the SBI interface allows all NFs to transmit and receive control signals using a single common SBI interface, only one interface and communication protocol stack need to be implemented and maintained when the SBI interface is used. Ultimately, using the SBI interface not only improves the efficiency of the communication system but also enables the efficient utilization of various resources, such as time, manpower, and cost, in the development of the communication system.

[0148] Another disadvantage of P2P-based interfaces is the strong functional dependency between two NFs connected via such interfaces. This means that adding a new feature to one NF or updating an existing one can affect the other NF, potentially requiring modifications to its functions. Furthermore, it may even necessitate modifications to the P2P interface connecting the two NFs itself. Consequently, performing new or existing feature updates leads to an increase in unnecessary work, such as modifying the other NF and the interface. This can cause network operators to miss the appropriate timing for launching new features into the market, thereby imposing significant restrictions on their ability to provide seamless services.

[0149] Finally, communication protocol stacks that implement the conventional N2 interface are not suitable for 6GS, which is based on cloud-native architecture. For example, SCTP (Stream Control Transmission Protocol) and GTP (General Packet Radio Service (GPRS) Tunnelling Protocol), which implement the N2 interface, are protocols proposed for mobile communication networks. These protocols were proposed to address the issue where communication transmission lines between the RAN (202) and CN (Core Network) within the carrier network were unstable in the past, and they may no longer be useful now that network operators have deployed stable communication transmission lines.

[0150] Implementing a system based on cloud-native principles means implementing the system using open-source software based on containers. However, communication protocols used only in specific domains, such as SCTP, are highly likely not to be supported by open-source software or Kubernetes, which manages containers. Therefore, when using communication protocols like SCTP, the network manufacturer must ultimately implement the protocol; since open-source software cannot be used for protocol management as well, the advantages of a cloud-native implementation cannot be utilized.

[0151] Furthermore, the high dependency between NFs, which is a disadvantage of the aforementioned P2P-based interface, also makes it unsuitable for cloud-native-based implementations. In cloud-native-based implementations, each function must have very loose dependencies on one another. By utilizing this characteristic, each function can be modularized and implemented within a container. In other words, each container is independent of the others, so modifications or updates to one container do not affect other containers. However, P2P interface-based NFs have very high dependencies between two NFs, making it difficult to modularize and implement them within a container.

[0152] In 6GS, there is an intention to more fully utilize IT technologies applied in 5GS (such as SDN (Software-Defined Network) and NFV (Network Function Virtualization)), which significantly reduced the CAPEX / OPEX (Capital Expenditure / Operational Expenditure) of network operators, and to this end, a Cloud-native 6GC is being pursued. The SBI-based N2 interface is implemented using a widely used communication protocol stack (currently using HTTP / 2 over TCP / IP, but the use of HTTP / 3 over QUIC is also being considered for 6G), and since all NFs operate independently, it is an interface that is very suitable for cloud-native-based implementation.

[0153] FIGS. 7a and 7b are drawings illustrating a network registration procedure of a conventional terminal according to one embodiment of the present disclosure.

[0154] In step S701, the terminal (UE, 710) can transmit a Registration Request message to the base station (R)AN (720). The Registration Request message may include the following parameters.

[0155] AN message (AN parameters, Registration Request (Registration type, SUCI or 5G-GUTI or PEI, [last visited TAI (if available)], Security parameters, [Requested NSSAI], [Mapping Of Requested NSSAI], [Default Configured NSSAI Indication], [UE Radio Capability Update], [UE MM Core Network Capability], [PDU Session status], [List Of PDU Sessions To Be Activated], [Follow-on request], [MICO mode preference], [Requested Active Time], [Requested DRX parameters for E-UTRA and NR], [Requested DRX parameters for NB-IoT], [extended idle mode DRX parameters], [LADN DNN(s) or Indicator Of Requesting LADN Information], [NAS message container], [Support for restriction of use of Enhanced Coverage], [Preferred Network Behaviour], [UE paging probability information], [Paging Subgrouping Support Indication], [UE Policy Container (list of PSIs, indication of UE support for ANDSP, operating system identifier, Indication of URSP Provisioning Support in EPS,UE capability of reporting URSP rule enforcement to network, UE capability of supporting VPLMN-specific URSP rules)] and [UE Radio Capability ID], [Release Request indication], [Paging Restriction Information], PEI, [PLMN with Disaster Condition], [Requested Periodic Update time], [Unavailability Period Duration], [Start of Unavailability Period], [Unavailability Type])).,

[0156] If (R)AN(720) is an NG-RAN, the AN (Access Network) parameters may include the following values: 5G-S-TMSI or GUAMI, Selected PLMN ID (or PLMN ID and NID) and NSSAI information, Establishment cause.

[0157] 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) ​​is a form of terminal ID and is a shortened form of 5G-GUTI (5G Globally Unique Temporary Identifier). 5G-S-TMSI consists of an AMF Set ID, an AMF Pointer, and 5G-TMSI, and can be used in wireless signaling procedures.

[0158] GUAMI (Globally Unique AMF Identifier) ​​is a form of AMF ID that can be used to identify a single AMF or one or more AMFs. GUAMI may consist of an MCC, MNC, AMF Region ID, AMF Set ID, and AMF Pointer.

[0159] A PLMN (Public Land Mobile Network) ID is the ID of a mobile carrier. A PLMN ID consists of an MCC (Mobile Country Code) and an MNC (Mobile Network Code).

[0160] A Network Identifier (NID) is an ID used to identify a Stand-alone Non-public Network (SNPN). An SNPN can be identified by using the PLMN ID and the NID together.

[0161] The values ​​included in the NSSAI (Network Slice Selection Assistance Information) information are determined by the Access Stratum Connection Establishment NSSAI Inclusion Mode parameter provided by AMF.

[0162] The Establishment cause value indicates the purpose for which the terminal requested the creation of an RRC (Radio Resource Control) connection.

[0163] If the terminal is an IAB (Integrated access and backhaul)-node connecting to 5GS, the AN parameter must include IAB-Indication.

[0164] If the terminal is part of an MBSR (Mobile Base Station Relay) node, the AN parameter must include an MBSR indication.

[0165] The Registration type value indicates the purpose for which the terminal requests registration. The Registration type value can be set to one of the following values: Initial Registration, Mobility Registration Update, Periodic Registration Update, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Update.

[0166] SUCI (Subscription Concealed Identifier) ​​is a form of terminal ID that includes a concealed SUPI value to prevent the leakage of the SUPI (Subscription Permanent Identifier) ​​value.

[0167] 5G-GUTI (5G Globally Unique Temporary Identifier) ​​is a form of terminal ID assigned to a terminal by the AMF. 5G-GUTI consists of GUAMI and 5G-TMSI.

[0168] PEI (Permanent Equipment Identifier) ​​is an identifier for identifying ME (Mobile Equipment). If the terminal supports at least one 3GPP access technology (i.e., NG-RAN, E-UTRAN, UTRAN, or GERAN), the PEI form must be set to IMEI (International Mobile Equipment Identity) or IMEISV (International Mobile Equipment Identity-Software Version).

[0169] The last visited TAI (Tracking Area Identity) represents the TAI value that the terminal last visited. The above last visited TAI value can be used by the AMF to determine the terminal's RA (Registration Area).

[0170] Security parameter values ​​are used for the terminal's authentication and integrity protection.

[0171] The requested NSSAI value includes the S-NSSAI(s) (Single Network Slice Selection Assistance Information) value corresponding to the Network Slice(s) that the terminal wishes to use.

[0172] The Mapping of Requested NSSAI value includes the HPLMN S-NSSAI value.

[0173] When the terminal uses E-UTRA (Evolved UTRA), the terminal may indicate whether to support CIoT (Cellular IoT) 5GS Optimizations. The support indicated by the terminal may affect the selection of AMF.

[0174] When a terminal performs Initial Registration or Disaster Roaming Registration, the terminal must include the following terminal identifier in the registration request message.

[0175] i. If the terminal has a valid EPS (Evolved Packet System) GUTI, the 5G-GUTI mapped to it.

[0176] ii. If possible, the native 5G-GUTI assigned by the PLMN that the terminal is attempting to register with.

[0177] iii. If possible, the native 5G-GUTI assigned by the equivalent PLMN of the PLMN for which the terminal attempts to register.

[0178] iv. If possible, native 5G-GUTI assigned by another PLMN.

[0179] v. If all of the above are not possible, the terminal must include its SUCI in the registration request message.

[0180] In the present disclosure, the terminal may include HPLMN Information (HPLMN ID and terminal GPSI of HPLMN) values ​​in the registration request message. Additionally, the terminal may include a Follow-on request in the registration request message to inform the network that the terminal will immediately create a PDU Session after registration.

[0181] In step S703, the base station NG-RAN (720) may select an AMF based on the Requested NSSAI if the AN parameters do not include 5G-S-TMSI or GUAMI, or if these values ​​indicate an AMF that is invalid. When the (R)AN) (720) selects an AMF based on the Requested NSSAI, it may select an AMF that supports the network slice included in the Requested NSSAI.

[0182] The existing NG-RAN (720) performed the AMF and NG SETUP procedures using the NG-C interface. Through this, the NG-RAN (720) stored configuration information of all AMFs connected to it internally. Based on the configuration information of the stored AMFs, the NG-RAN (720) can search for and select an AMF that can support the terminal's location information, the requested network slice value, the terminal's type (e.g., IAB-node, CIoT, etc.), and the functions requested by the terminal to the network.

[0183] Searching for and selecting NFs based on SBI can be performed using NRFs. In this case, each NF does not need to store any information about the NFs to be searched. In other words, the RESTful-based stateless design principles required by 3GPP standards can be implemented in a cloud-native environment. Furthermore, since the NF Profile information obtained through NRFs is centralized and is always updated with the latest information, load balancing and resource efficiency among NFs can be further enhanced during the NF selection process.

[0184] In step S705, the NG-RAN (720) may send a registration request message to the selected AMF. At this time, the registration request message sent by the NG-RAN (720) may include N2 parameters and an LTE-M indication. The N2 parameters may include the following values: Selected PLMN ID (if NPN, PLMN ID and NID), Location Information where the terminal is located, Cell Identity, and UE Context Request.

[0185] At step S707, if the selected AMF is the new AMF (730), it may send a Namf_Communication_UEContextTransfer message to the old AMF (740) or a Nudsf_UnstructuredDataManagement_Query to the UDSF. Then, at step S709, the selected new AMF (730) may receive a Namf_Communication_UEContextTransfer response message from the old AMF (740). This message may include the following values: SUPI, UE Context in AMF. Alternatively, the selected new AMF (730) may receive a Nudsf_UnstructuredDataManagement_Query message from the UDSF, which may include terminal-related data.

[0186] In step S711, if the selected new AMF (730) receives SUCI from the terminal (710) and the old AMF (740), it may send an identity request message requesting SUCI to the terminal (710). Then, in step S713, the selected new AMF (730) may receive an identity response message containing the terminal SUCI from the terminal (710).

[0187] In step S715, the selected new AMF (730) can perform authentication of the terminal (710). The new AMF (730) can select an AUSF based on the terminal's SUPI or SUCI.

[0188] If authentication of the terminal is required in step S717, the selected new AMF (730) may request authentication of the terminal from the AUSF selected in step S715.

[0189] In step S717, if the terminal NAS security context does not exist, NAS security initiation can be performed.

[0190] The selected new AMF (730) can perform an NGAP procedure to provide a security context to the 5G-AN. The 5G-AN can store the security context provided by the selected new AMF (730) and send an acknowledgment to the selected new AMF (730).

[0191] In step S719, the new AMF (730) may send a Namf_Communication_RegistrationStatusUpdate message to the old AMF (740). This message may include PDU Session ID(s) that are released due to a network slice that the selected new AMF (730) cannot provide.

[0192] In step S721, the new AMF (730) can perform the transmission and reception of an identifier request message and an identifier response message requesting the PEI of the terminal.

[0193] In step S723, the new AMF (730) can perform N5g-eir_EquipmentIdentityChenk_Get on the equipment identity register (EIR) to check the terminal ME Identity.

[0194] In step S725, the new AMF (730) can perform UDM selection based on terminal SUPI. The UDM (780) can perform UDR instance selection.

[0195] In step S727a, if the new AMF (730) has not registered the terminal (710) in the UDM, it can register the terminal (710) in the UDM by sending a Nudm_UECM_Registration message to the UDM (780).

[0196] In step S727b, the new AMF (730) can obtain the terminal's subscriber information (e.g., Access and Mobility Subscription data) from the UDM (780).

[0197] In step S727c, the new AMF (730) can send the Nudm_SDM_Subscribe message to the UDM (780).

[0198] In step S727d, the old AMF (740) can receive a Nudm_UECM_DeregistrationNotify message from the UDM. Then, in step S727e, the old AMF (740) can send a Nudm_SDM_Unsubscribe message to the UDM.

[0199] In step S729, the new AMF (730) can perform PCF selection.

[0200] In step S731, the new AMF (730) can perform the AM Policy Association Establishment / Modification procedure with the PCF (750) selected in the previous step.

[0201] In step S733, the new AMF (730) can send the Nsmf_PDUSession_UpdateSMContext / Nsmf_PDUSession_ReleaseSMContext message to the SMF (760).

[0202] If the List Of PDU Session To Be Activated value was included in the registration request message, new AMF (730) can activate the User Plane connection(s) of the corresponding PDU Session(s) by sending the Nsmf_PDUSession_UpdateSMContext Request message to SMF (760).

[0203] If the PDU Session status indicates that the PDU Session(s) have been released, the new AMF (730) can request the release of the PDU Session(s) by sending an Nsmf_PDUSession_ReleaseSMContext Request message to the SMF (760).

[0204] In step S735, the new AMF (730) can send a UE Context Modification Request message to N3IWF / TNGF. And in step S737, the new AMF (730) can receive a UE Context Modification Response message from N3IWF / TNGF.

[0205] In step S739, the new AMF (730) can register by sending a Nudm_UECM_Registration message to the UDM (780) after receiving the UE Context Notification Response message from the N3IWF / TNGF in step S737. At this time, the Access Type can be set to "non-3GPP access".

[0206] In step S741, the UDM (780) can send a Nudm_UECM_DeregistrationNotify message to the old AMF (740). Then, in step S743, the old AMF (740) can send a Nudm_SDM_Unsubscribe message to the UDM (780).

[0207] In step S745, the new AMF (730) can send a Registration Accept message to the terminal (710). The Registration Accept message may include the following values.

[0208] 5G-GUTI, Registration Area, [Mobility restrictions], [PDU Session status], [Allowed NSSAI], [Mapping Of Allowed NSSAI], [Partially Allowed NSSAI], [Mapping Of Partially Allowed NSSAI], [TAI List for S-NSSAIs in Partially Allowed NSSAI], [Configured NSSAI for the Serving PLMN], [Mapping Of Configured NSSAI], [NSSRG Information], [NSAG Information], [rejected S-NSSAIs], [TAI List for any rejected S-NSSAI Partially in the RA], [Pending NSSAI], [Mapping Of Pending NSSAI], [Periodic Registration Update timer], [Active Time], [Strictly Periodic Registration Timer Indication], [LADN Information], [MICO Indication], [IMS Voice over PS session supported Indication], [Emergency Service Support indicator], [Accepted DRX parameters for E-UTRA and NR], [Accepted DRX parameters for NB-IoT], [extended idle mode DRX parameters], [Paging Time Window], [Network support of Interworking without N26], [Access Stratum Connection Establishment NSSAI Inclusion Mode],[Network Slicing Subscription Change Indication], [Operator-defined access category definitions], [List of equivalent PLMNs], [Enhanced Coverage Restricted information], [Supported Network Behaviour], [Service Gap Time], [PLMN-assigned UE Radio Capability ID], [PLMN-assigned UE Radio Capability ID deletion], [WUS Assistance Information], [AMF PEIPS Assistance Information], [Truncated 5G-S-TMSI Configuration], [Connection Release Supported], [Paging Cause Indication for Voice Service Supported], [Paging Restriction Supported], [Reject Paging Request Supported], [Paging Restriction Information acceptance / rejection], ["List of PLMN(s) to be used in Disaster Condition"], [Disaster Roaming wait range information], [Disaster Return wait range information], [Forbidden TAI(s)], [List of equivalent SNPNs], [Registered NID], [Unavailability Period Support], [MBSR authorization information], [Return To Coverage Notification Not Required], [Unavailability Period Duration],[Start of Unavailability Period], [S-NSSAI location availability information], [Mapping Of Alternative NSSAI], [Slice Usage Policy], [Maximum Time Offset].,

[0209] In step S747, the new AMF (730) can perform the UE Policy Association Establishment procedure with the PCF (750).

[0210] The terminal that received the registration acceptance message in step S749 can send a registration complete message to the new AMF (730).

[0211] In step S751, the new AMF (730) can send and receive Nudm_SDM_info to and from the UDM (780).

[0212] In step S753, if the terminal registers using 3GPP access and the new AMF (730) does not disconnect the signaling connection to the (R)AN, the new AMF (730) can transmit RRC Inactive Assistance Information to the (R)AN (720).

[0213] In step S755, the new AMF (730) can send a Nudm_UECM_Update message to the UDM (780).

[0214] And at step S757, the terminal (710) indicates that Network Slice-Specific Authentication and Authorization can be performed in the UE MM Core Network Capability, and if Network Slice-Specific Authentication and Authorization is required among the requested S-NSSAIs, the new AMF (730) can initiate a Network slice-specific authentication and authorization procedure.

[0215] FIG. 8 is a diagram illustrating a network registration procedure for a terminal in a network structure to which an SBI-based N2 interface is applied according to one embodiment of the present disclosure.

[0216] Figure 8 is a diagram for explaining in detail only the part of the procedure in which the NG-RAN (820) searches for and selects an AMF based on the terminal network registration procedure of Figure 7.

[0217] In step S801, the terminal (810) can transmit a Registration Request message to the base station (R)AN (820). The Registration Request message may include the following parameters.

[0218] AN message (AN parameters, Registration Request (Registration type, SUCI or 5G-GUTI or PEI, [last visited TAI (if available)], Security parameters, [Requested NSSAI], [Mapping Of Requested NSSAI], [Default Configured NSSAI Indication], [UE Radio Capability Update], [UE MM Core Network Capability], [PDU Session status], [List Of PDU Sessions To Be Activated], [Follow-on request], [MICO mode preference], [Requested Active Time], [Requested DRX parameters for E-UTRA and NR], [Requested DRX parameters for NB-IoT], [extended idle mode DRX parameters], [LADN DNN(s) or Indicator Of Requesting LADN Information], [NAS message container], [Support for restriction of use of Enhanced Coverage], [Preferred Network Behaviour], [UE paging probability information], [Paging Subgrouping Support Indication], [UE Policy Container (list of PSIs, indication of UE support for ANDSP, operating system identifier, Indication of URSP Provisioning Support in EPS,UE capability of reporting URSP rule enforcement to network, UE capability of supporting VPLMN-specific URSP rules)] and [UE Radio Capability ID], [Release Request indication], [Paging Restriction Information], PEI, [PLMN with Disaster Condition], [Requested Periodic Update time], [Unavailability Period Duration], [Start of Unavailability Period], [Unavailability Type])).,

[0219] (R) If the AN is an NG-RAN, the AN (Access Network) parameters may include the following values: 5G-S-TMSI or GUAMI, Selected PLMN ID (or PLMN ID and NID) and NSSAI information, Establishment cause.

[0220] 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) ​​is a form of terminal ID and is a shortened form of 5G-GUTI (5G Globally Unique Temporary Identifier). 5G-S-TMSI consists of AMF Set ID, AMF Pointer, and 5G-TMSI and is used in the wireless signaling procedure.

[0221] GUAMI (Globally Unique AMF Identifier) ​​is a form of AMF ID capable of identifying a single AMF or one or more AMFs. GUAMI consists of an MCC, MNC, AMF Region ID, AMF Set ID, and AMF Pointer.

[0222] A PLMN (Public Land Mobile Network) ID is the ID of a mobile carrier. A PLMN ID consists of an MCC (Mobile Country Code) and an MNC (Mobile Network Code).

[0223] The NID (Network Identifier) ​​is an ID used to identify a Stand-alone Non-public Network (SNPN). The SNPN is identified by using the PLMN ID and the NID together.

[0224] The values ​​included in the NSSAI (Network Slice Selection Assistance Information) information are determined by the Access Stratum Connection Establishment NSSAI Inclusion Mode parameter provided by AMF.

[0225] The Establishment cause value indicates the purpose for which the terminal requested the creation of an RRC (Radio Resource Control) connection.

[0226] If the terminal (810) is an IAB (Integrated access and backhaul)-node connecting to 5GS, the AN parameter must include an IAB-Indication.

[0227] If the terminal (810) is part of the MBSR (Mobile Base Station Relay) node, the AN parameter must include the MBSR Indication.

[0228] The Registration type value indicates the purpose for which the terminal requests registration. The Registration type value may be set to one of the following values: Initial Registration, Mobility Registration Update, Periodic Registration Update, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Update.

[0229] SUCI (Subscription Concealed Identifier) ​​is a form of terminal ID that includes a concealed SUPI value for the purpose of preventing the leakage of the SUPI (Subscription Permanent Identifier) ​​value.

[0230] 5G-GUTI (5G Globally Unique Temporary Identifier) ​​is a form of terminal ID that is assigned to the terminal (810) by the AMF. 5G-GUTI consists of GUAMI and 5G-TMSI.

[0231] PEI (Permanent Equipment Identifier) ​​identifies ME (Mobile Equipment). If the terminal (810) supports at least one 3GPP access technology (i.e., NG-RAN, E-UTRAN, UTRAN, or GERAN), the PEI form must be set to IMEI (International Mobile Equipment Identity) or IMEISV (International Mobile Equipment Identity-Software Version).

[0232] The last visited TAI (Tracking Area Identity) represents the TAI value that the terminal last visited. The above last visited TAI value is used by the AMF to determine the terminal's RA (Registration Area).

[0233] Security parameter values ​​are used for terminal authentication and integrity protection.

[0234] The requested NSSAI value includes the S-NSSAI(s) (Single Network Slice Selection Assistance Information) value corresponding to the network slice(s) that the terminal wishes to use.

[0235] The Mapping of Requested NSSAI value includes the HPLMN S-NSSAI value.

[0236] When the terminal (810) uses E-UTRA (Evolved UTRA), the terminal (810) indicates whether it supports CIoT (Cellular IoT) 5GS Optimizations. The support indicated by the terminal (810) affects the AMF selection.

[0237] If the terminal (810) performs initial registration or disaster roaming registration, the terminal (810) must indicate the terminal's identifier in the registration request message as follows.

[0238] i. If the terminal has a valid EPS (Evolved Packet System) GUTI, the 5G-GUTI mapped to it.

[0239] ii. If possible, the native 5G-GUTI assigned by the PLMN that the terminal is attempting to register with.

[0240] iii. If possible, the native 5G-GUTI assigned by the equivalent PLMN of the PLMN for which the terminal attempts to register.

[0241] iv. If possible, native 5G-GUTI assigned by another PLMN.

[0242] v. If all of the above are not possible, the terminal must include its SUCI in the registration request message.

[0243] In the present disclosure, the terminal (810) may include HPLMN Information (HPLMN ID and terminal GPSI of HPLMN) values ​​in the registration request message. Additionally, the terminal (810) may include a Follow-on request in the registration request message to inform the network that the terminal (810) will immediately create a PDU Session after registration.

[0244] In step S803, the base station NG-RAN (820) may select an AMF based on the Requested NSSAI if the AN parameters do not include 5G-S-TMSI or GUAMI, or if these values ​​indicate an AMF that is invalid.

[0245] In an Evolved SBA structure with an SBI-based N2 interface, the N2 interface can be replaced from the conventional NG-C interface to the SBI interface. With this replacement of the interface, various NG SETUP procedures, including the TNL association setup procedure for configuring the conventional NG-C interface, may not be performed. This means that the NG-RAN does not need to store configuration information of AMFs to perform the search and selection of an AMF to handle a terminal.

[0246] NG-RAN (820) can use the NF Discovery service, which other NFs use to search for and select NFs or NF services provided by NFs, by using the SBI interface. The NF Discovery procedure will be explained in FIG. 9.

[0247] NG-RAN (820) can search for and select an AMF that can support this based on the location information of the terminal (810), the requested network slice value, the type of the terminal (e.g., IAB-node, CIoT, etc.), and the functions requested by the terminal to the network using the NRF service.

[0248] In step S805, the NG-RAN (820) may send an Nng-ran_Communication_InitialNASMessageTransfer message to the selected new AMF (830). This message may be for receiving the Initial NAS Message Transfer service provided by the NG-RAN. The Initial NAS Message Transfer service may provide a service for delivering the terminal's initial NAS message to the network. This message may include the following values.

[0249] AMF ID, NG-RAN ID (eg Global RAN Node ID), RAN UE ID

[0250] 5G-S-TMSI (if available)

[0251] NAS Message type [MM, SM, SMS, LCS and UE Policy], ULI

[0252] RRC Establishment Cause [emergency, highPriorityAccess, mt-Access, mo-Signalling, mo-Data, mo-VoiceCall, mo-VideoCall, mo-SMS, mps-PriorityAccess, mcs-PriorityAccess]

[0253] NAS Message container [Registration Request]

[0254] Looking closely, Nng-ran_Communication_InitialNASMessageTransfer may include the AMF ID of the message recipient and the NG-RAN ID of the message sender. Additionally, the message may include 5G-S-TMSI, which is the ID of the terminal requesting the NAS message transmission, the type of NAS message to be transmitted (based on 5GS, this value can be set to one of MM, SM, SMS, LCS, and UE Policy), the reason the terminal requested the RRC setting, and a NAS Message container containing the NAS message transmitted by the terminal.

[0255] In the procedure of Fig. 8, the NAS Message Type is set to the value MM, and the NAS Message container can contain a Registration Request message.

[0256] The Nng-ran_Communication_InitialNASMessageTransfer message may additionally include the following information: 5G-S-TMSI, UE Context Request, Allowed NSSAI, Partially Allowed NSSAI, Source to Target AMF Information Reroute, PLMN ID, IAB indication, Mobile IAB indication, CE-mode-B Support indication, LTE-M indication, EDT Session, Authenticated indication, NPN Access Information, RedCap indication, eRedCap indication, selected NID.

[0257] Since the NF service of the NG-RAN in the present disclosure is proposed based on the conventional 5GS, the names of the NF service and the parameters included in the messages can be deleted, modified, or added to suit the 6G network structure.

[0258] At step S807, if the selected AMF is new AMF (830), the new AMF (830) may send a Namf_Communication_UEContextTransfer message to the old AMF (840) or a Nudsf_UnstructuredDataManagement_Query to the UDSF. Then, at step S509, the selected new AMF (830) may receive a Namf_Communication_UEContextTransfer response message from the old AMF (840). This message may include the following values: SUPI, UE Context in AMF. Alternatively, the selected new AMF (830) may receive a Nudsf_UnstructuredDataManagement_Query message from the UDSF. This message may include terminal-related data.

[0259] In step S811, the new AMF (830) may send an Nng-ran_Communication_DLNASMessageTransfer message to the NG-RAN (820). This message may be a message requesting the DL NAS Message Transfer service of the NG-RAN. The NFs of the core network may request the NG-RAN (811), which is responsible for the wireless link, to send a NAS message to the terminal (810). This message may include the following values.

[0260] AMF ID, NG-RAN ID, RAN UE ID, AMF UE ID

[0261] 5G-S-TMSI (if available)

[0262] NAS Message type [MM, SM, SMS, LCS and UE Policy]

[0263] NAS Message container [Identity Request]

[0264] Looking closely, the Nng-ran_Communication_DLNASMessageTransfer message may include an AMF ID, which is the sender of the message, and an NG-RAN ID, which is the recipient of the message. Additionally, a RAN UE ID and an AMF UE ID may be added to distinguish the session of the terminal (810) transmitting the NAS message. It may include 5G-S-TMSI, which is the ID of the terminal receiving the NAS message, the type of the NAS message being transmitted (based on 5GS, this value can be set to one of MM, SM, SMS, LCS, and UE Policy), the reason why the terminal (810) requested the RRC setting, and a NAS Message container containing the NAS message transmitted by the terminal (810).

[0265] In the procedure of Fig. 8, the NAS Message Type is set to the MM value, and the NAS Message container may include an Identity Request message. The Identity Request message is a NAS message in which the AMF requests the SUPI value, which is the ID of the terminal.

[0266] The Nng-ran_Communication_InitialNASMessageTransfer message may include the following additional information.

[0267] Old AMF, RAN Paging Priority, Mobility Restriction List, Index to RAT / Frequency Selection Priority, UE Aggregate Maximum Bit Rate, Allowed NSSAI, SRVCC Operation Possible, Enhanced Coverage Restriction, Extended Connected Time, UE Differentiation Information, CE-mode-B Restricted, UE Radio Capability, UE Capability Info Request, End Indication, UE Radio Capability ID, Target NSSAI Information, Masked IMEISV, Partially Allowed NSSAI, Mobile IAB Authorized.

[0268] Since the NF service of the NG-RAN in the present disclosure is proposed based on the conventional 5GS, the names of the NF service and the parameters included in the messages can be deleted, modified, or added to suit the 6G network structure.

[0269] In step S813, if the selected new AMF (830) receives SUCI from the terminal (810) and the old AMF (840), it may send an Identity request message requesting SUCI to the terminal (810). Then, in step S815, the selected new AMF (830) may receive an Identity response message containing the terminal SUCI from the terminal (810).

[0270] Subsequent terminal registration procedures may be applied by modifying the conventional procedures according to the network structure using an SBI-based N2 interface.

[0271] FIG. 9 illustrates the AMF search and selection procedure of NG-RAN (910) using NRF (920).

[0272] In Fig. 8, the NG-RAN no longer stores configuration information of the AMF as it uses the SBI interface. The NG-RAN can use the SBI interface to search for and select an AMF to handle a terminal requesting registration.

[0273] All NF instances must create an NF profile and register it with the NRF when instantiated. An NF profile may include a list of services provided by each NF, connection information (e.g., FQDN, IP address), load information, etc.

[0274] In step S901, the NG-RAN (910) may send an Nnrf_NFDiscovery_Request message to the NRF (920) to search for an AMF to handle the terminal. This message may include the following information.

[0275] NF type of target NF: AMF

[0276] NF type of NF service consumer: NG-RAN

[0277] TAC, PLMN ID, Requested NSSAI

[0278] AMF, which is the type of the NF being searched; NG-RAN, which is the NF type of the NF requesting the Discovery service; TAC (Tracking Area Code), which is the responsibility of the searching AMF; PLMN (Public Land Mobile Network) ID; and Requested NSSAI, the network slice information requested by the terminal.

[0279] The Nnrf_NFDiscovery_Request message may additionally include the following information: 5G CIoT features, IAB-indication, NB-IoT RAT Type, Category M Indication, NR RedCap Indication, SNPN Onboarding indication, Mobile IAB-indication, CE-mode-B indicator.

[0280] In step S903, NRF (920) can review the authority of NG-RAN (910) regarding the NF Discovery request received from NG-RAN (910).

[0281] If it is determined in step S905 that the NG-RAN has the authority to perform an NF Discovery request, the NRF (920) may respond to the request using the Nnrf_NFDiscovery_Request Response message. This message may include the following information.

[0282] A set of AMF NF instance profile(s)

[0283] NF Set ID, NF instance ID, NF type, PLMN ID, GUAMI(s)

[0284] IP address or FQDN of NF instance

[0285] NF capacity information, NF priority information, NF load information

[0286] List of S-NSSAI and NSI ID, Location information, list of TAI(s)

[0287] Looking closely, the Nnrf_NFDiscovery_Request Response message can transmit NF instance profiles of AMFs that meet the conditions requested by the NR-RAN (910). Each NF instance profile may include an NF Set ID, an NF instance ID, an NF type, a PLMN ID, and a GUAMI. The message may include the IP address or FQDN information of the NF instance so that the NG-RAN (910) can request services from the NF instance, and may include load information of each instance for load balancing of the NF instances. Additionally, the message may include network slice information, location information, and a list of IDs for the Tracking Area (TA) responsible for each AMF instance.

[0288] In step S907, the NG-RAN can select an AMF NF instance to be in charge of the terminal based on the information of the received NF profiles, taking into account the load information and network policy of each instance.

[0289] FIG. 10 is a block diagram of a terminal or user equipment (1000) according to one embodiment of the present disclosure.

[0290] The terminal (1000) is an electronic device capable of wireless communication and may include user equipment (UE), a mobile phone, a smartphone, a tablet, an Internet of Things (IoT) device having various form factors, and can perform wireless communication with a base station through a wireless channel.

[0291] Referring to FIG. 10, the terminal (1000) may include at least one transceiver (1001) (hereinafter, transceiver), at least one processor (1002) (hereinafter, processor), and at least one memory (1003) (hereinafter, memory). According to at least one or a combination thereof of methods corresponding to embodiments of the present disclosure, the transceiver (1001), processor (1002), and memory (1003) of the terminal (1000) may be operated. However, the components of the terminal (1000) are not limited to the examples of components shown in FIG. 10. In other embodiments, the terminal (1000) may include additional components in addition to the aforementioned components, or some components may be omitted. Also, in some embodiments, any combination of the transceiver (1001), processor (1002), or memory (1003) may be integrated into a single component.

[0292] The transceiver (1001) may be a basic communication circuit or communication circuitry that enables the terminal (1000) to perform wireless communication with a node or entity of a network. For example, the transceiver (1001) may enable the terminal (1000) to transmit and receive signals to and from a base station via cellular wireless communication, or to transmit and receive signals to and from another terminal via cellular wireless communication. For example, the transceiver (1001) may be 3G (3rd generation), 4G (4th generation), LTE (long-term evolution), 5G (5th generation), NR (new radio), 6G (6th It can support at least one of various cellular wireless communication technologies including (generation), and the various cellular wireless communication technologies supported by the transceiver (1001) may include all subsequent evolved generations of wireless communication.

[0293] According to one embodiment, the terminal (1000) may include a plurality of transceivers, and for example, when supporting EN-DC (E-UTRA (evolved-universal terrestrial radio access) - NR dual connectivity), it may include a first transceiver supporting 4G LTE wireless communication and a second transceiver supporting 5G NR wireless communication. According to another embodiment, when the terminal (1000) supports NR-DC (NR Dual Connectivity), the terminal (1000) may include a plurality of transceivers supporting 5G NR wireless communication. According to another embodiment, if the terminal (1000) supports short-range wireless communication, the terminal (1000) may separately include a transceiver that supports at least one of a group of wireless communication protocol standards such as those defined by Bluetooth®, wireless LAN or WLAN (wireless local area network) network (including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba and 802.11be).

[0294] According to one embodiment, the transceiver (1001) may include various circuit structures used to transmit and receive signals to and from a base station via a wireless channel. The signals may include control information and data. For example, the transceiver (1001) may be configured to include a radio frequency (RF) transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. The transceiver (1001) may output the signal received via the wireless channel to a processor (1002) and transmit the signal output from the processor (1002) via the wireless channel.

[0295] A processor (1002) can control the overall operation of a terminal (1000) according to an embodiment of the present disclosure. The processor (1002) may be implemented as one or more IC (integrated circuit (or circuitry)) chips and may perform various data processing operations. The processor (1002) may include at least one electrical circuit and may execute instructions (or programs, code, data, etc.) stored in memory (1003) individually, collectively, or in any combination. Additionally, the processor (1002) may include a single-core processor or a multi-core processor, and in a specific implementation, may be composed of a processor assembly including a plurality of processing circuits.

[0296] The processor (1002) is electrically, operatively, or communicatively coupled to the transceiver (1001) so as to control the transceiver (1001).

[0297] The processor (1002) may include at least one processor (or, processing circuitry), and at least one processor may perform the following operations individually, collectively, or in any combination. For example, the processor (1002) may include a communication processor (CP) that controls communication operations and an application processor (AP) that controls the execution of an upper layer (e.g., an application layer). In a specific embodiment, at least one part of the processor (1002) may be included in one chip, and another part of the processor (1002) may be included in a separate chip. Alternatively, at least one processor may be included in other components, e.g., a transceiver (1001) or a memory (1003).

[0298] The processor (1002) may perform, cause, or control the operation of a terminal to perform at least one or a combination of the methods according to the embodiments of the present disclosure. For example, the processor (1002) may control the operation of a terminal to process a downlink signal received from a base station or to generate an uplink signal and transmit it to a base station. To this end, the processor (1002) may control other components of the terminal (1000) to perform various operations by executing computer programs, code, or instructions stored in memory (1003).

[0299] Memory (1003) is a hardware storage device capable of storing information temporarily or permanently and may include one or more storage media. For example, memory (1003) may include a memory assembly comprising one or more storage media. For example, the one or more storage media may include a hard drive, flash memory, permanent memory such as ROM (read-only memory), semipermanent memory such as RAM (random access memory), cache memory, or any combination thereof.

[0300] The memory (1003) can be electrically, operatively, or communically coupled with the processor (1002) and can be accessed by the processor (1002).

[0301] A computer program, code, or instruction that can be executed by a processor (1002) may be stored in the memory (1003). According to one embodiment, the computer program, code, or instruction that can be executed by the processor (1002) may be stored in a single memory device or may be separated and distributed across two or more memory devices. The processor (1002) may perform various functions according to the embodiments of the present disclosure by executing the instruction stored in the memory (1003).

[0302] According to one embodiment of the present disclosure, the operation of the terminal (1000) may be caused to be performed based on at least one processor (or processing circuit) configured to perform the features of the present disclosure individually, collectively, or in any combination based on the execution of instructions (or computer program or code) stored in memory (1003), based on processing circuitry not configured to execute instructions, and / or based on components of a processing circuitry not configured to execute instructions.

[0303] FIG. 11 is a block diagram of a base station (1100) according to one embodiment of the present disclosure.

[0304] The base station (1100) can perform wireless communication with at least one terminal within the area of ​​the base station (1100) through a wireless channel.

[0305] Referring to FIG. 11, a base station (1100) may include at least one transceiver (1101) (hereinafter, transceiver), at least one processor (1102) (hereinafter, processor), and at least one memory (1103) (hereinafter, memory). According to at least one or a combination thereof of methods corresponding to embodiments of the present disclosure, the transceiver (1101), processor (1102), and memory (1103) of the base station (1100) may be operated. However, the components of the base station (1100) are not limited to the examples of components shown in FIG. 11. In other embodiments, the base station (1100) may include additional components in addition to the aforementioned components, or some components may be omitted. Also, in some embodiments, any combination of the transceiver (1101), processor (1102), or memory (1103) may be integrated into a single component.

[0306] The transceiver (1101) may be a communication circuit or communication circuitry that enables the base station (1100) to perform wireless communication with a node or entity of the network. For example, the transceiver (1101) may enable the base station (1100) to transmit and receive signals to and from a terminal (1000) via cellular wireless communication or to transmit and receive signals to and from other network entities via wireless communication. For example, the transceiver (1101) may be 3G (3rd generation), 4G (4th generation) LTE (long-term evolution), 5G (5th generation) NR (new radio), 6G (6th generation) Various cellular wireless communication technologies, including (generation), etc., can be supported, and the various cellular wireless communication technologies supported by the transceiver (1101) may include all subsequent evolved generations of wireless communication. According to one embodiment, the transceiver (1101) may include various circuit structures used to transmit and receive signals to and from a terminal via a wireless channel. The signals may include control information and data. For example, the transceiver (1101) may be configured to include an RF (radio frequency) transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. The transceiver (1101) may output the signal received via the wireless channel to a processor (1102) and transmit the signal output from the processor (1102) via the wireless channel.

[0307] Meanwhile, according to one embodiment of the present disclosure, a base station (1100) may communicate with an entity or node of a network via wired or wireless communication. For example, the base station (1100) may communicate via wired or wireless communication with an entity or node of an adjacent base station or core network via a backhaul network. Although not shown in the drawings, when the base station (1100) performs wired communication, the base station (1100) may include a separate network interface for wired communication in addition to the transceiver (1101). The network interface may be referred to as network interface circuitry, communication interface circuitry, etc.

[0308] A processor (1102) can control the overall operation of a base station (1100) according to an embodiment of the present disclosure. The processor (1102) may be implemented as one or more IC (integrated circuit or circuitry) chips and may perform various data processing operations. The processor (1102) may include at least one electrical circuit and may execute instructions (or programs, code, data, etc.) stored in memory (1103) individually, collectively, or in any combination. Additionally, the processor (1102) may include a single-core processor or a multi-core processor, and in a specific implementation, may be composed of a processor assembly including a plurality of processing circuits.

[0309] The processor (1102) is electrically, operatively, or communically coupled to the transceiver (1101) so as to control the transceiver (1101).

[0310] The processor (1102) may include at least one processor (or processor circuitry), and at least one processor may perform the following operations individually, collectively, or in any combination. In a particular embodiment, at least one part of the processor (1102) may be included in one chip, and another part of the processor (1102) may be included in a separate chip. Alternatively, at least one processor may be included in other components, such as a transceiver (1101) or memory (1103).

[0311] The processor (1102) may perform, cause, or control the operation of a base station to perform at least one or a combination of the methods according to the embodiments of the present disclosure. For example, the processor (1102) may control the operation of a base station to generate a downlink signal and transmit it to a terminal, or to process an uplink signal received from a terminal. Alternatively, the base station may transmit and receive signals with an adjacent base station, transmit a signal received from a terminal to an upper node of the network, or receive a signal from an upper node of the network and transmit it to a terminal. To this end, the processor (1102) may control other components of the base station (1100) to perform various operations by executing computer programs, codes, and instructions stored in memory (1103).

[0312] Memory (1103) is a hardware storage device capable of storing information temporarily or permanently and may include one or more storage media. For example, memory (1103) may include a memory assembly comprising one or more storage media. For example, the one or more storage media may include a hard drive, flash memory, permanent memory such as ROM (read-only memory), semi-permanent memory such as RAM (random access memory), cache memory, or any combination thereof.

[0313] The memory (1103) can be electrically, operatively, or communically coupled with the processor (1102) and can be accessed by the processor (1102).

[0314] A computer program, code, or instruction that can be executed by a processor (1102) may be stored in the memory (1103). According to one embodiment, the computer program, code, or instruction that can be executed by the processor (1102) may be stored in a single memory device or may be separated and distributed among two or more memory devices. The processor (1102) may perform various functions according to the embodiments of the present disclosure by executing the instruction stored in the memory (1103).

[0315] According to one embodiment of the present disclosure, the operation of a base station (1100) may be caused to be performed based on at least one processor (or processing circuit) configured to perform the features of the present disclosure individually, collectively, or in any combination based on the execution of instructions (or computer programs or code) stored in memory (1103), based on processing circuitry not configured to execute instructions, and / or based on components of a processing circuitry not configured to execute instructions.

[0316] A terminal or a base station can perform various communication procedures related to the control plane or user plane by interacting with network entities based on communication through a wireless channel. For example, a terminal can communicate with network entities such as an access and mobility management function (AMF) or a session management function (SMF) through a base station. Alternatively, the base station can perform at least one communication procedure by directly transmitting and receiving signals or relaying them with network entities. The structure of the above-mentioned network entities will be explained in more detail through the drawings below.

[0317] FIG. 12 is a block diagram of a network entity (1200) that performs network functions according to one embodiment of the present disclosure.

[0318] A network entity (1200) may include one or more network functions (NF) that constitute a core network (e.g., 5G (5th generation) core, 5GC) in a communication system, or entities (devices, devices, nodes, or servers, etc.) that perform part of a network function. In this case, multiple NFs may be implemented within a single network entity, or a single NF may be distributed and implemented across multiple network entities. Additionally, when an NF is implemented within a network entity, the NF may be implemented in the form of software, and in such cases, a program for running the NF may be loaded into the memory of the network entity (1200).

[0319] A single NF can be implemented as one or more instances and can operate by being distributed across the same network entity or multiple network entities. Here, the instance is a software unit that logically executes a specific network function and may be separate from physical hardware resources. Additionally, one or more NFs may be implemented as a single network slice to operate in order to satisfy the specifications required by a specific service.

[0320] The above NF may include any one of an access and mobility management function (AMF), a session management function (SMF), a local session management function (L-SMF), a user plane function (UPF), a local user plane function (L-UPF), a policy control function (PCF), unified data management (UDM), a unified data repository (UDR), a network exposure function (NEF), a network repository function (NRF), an application function (AF), a network slice selection function (NSSF), a network data analytics function (NWDAF), a network slice admission control function (NSACF), an authentication server function (AUSF), or a data network (DN).

[0321] Referring to FIG. 12, a network entity (1200) may include at least one network interface (1201), at least one processor (1202) (hereinafter referred to as processor), and at least one memory (1203) (hereinafter referred to as memory). As described above, the NF may be implemented in the form of a physical device such as the network entity (1200), or may be implemented and executed in the form of a virtualized instance. When the NF is implemented in the form of an instance, it may not necessarily include physical components as illustrated in FIG. 12. In such cases, the instance may be composed of one or more logical functional units and may be logically represented.

[0322] According to at least one or a combination thereof of the methods corresponding to the embodiments of the present disclosure, the network interface (1201), processor (1202), and memory (1203) of the network entity (1200) may be operated. However, the components of the network entity (1200) are not limited to the examples of components shown in FIG. 12. In other embodiments, the network entity (1200) may include additional components in addition to the aforementioned components, or some components may be omitted. Also, in one embodiment, the network interface (1201), processor (1202), or memory (1203) may be implemented as a single component.

[0323] The network interface (1201) is a collective term for the transmitting and receiving parts of a network entity and may be a communication circuit for transmitting and receiving signals with a terminal (user equipment, UE), a base station, or other network entities. In this case, the communication circuit may include both a communication circuit for wireless communication and a communication circuit for wired communication. For example, the network interface (1201) may include circuits, logic, hardware, etc. configured to exchange control plane messages or user plane messages with a terminal, a base station, or other core network entities via wireless or wired communication. The network interface (1201) may operate using various protocols (e.g., NAS (Non-Access Stratum) protocol). Depending on the convenience of explanation and technical implementation, the network interface (1201) may be referred to as a communication circuitry, a network interface circuitry, or a communication interface circuitry.

[0324] A processor (1202) may control the overall operation of a network entity (1200) according to an embodiment of the present disclosure. In one embodiment, the processor (1202) may be implemented as one or more IC (integrated circuit or circuitry) chips and may perform various data processing operations. The processor (1202) may include at least one electrical circuit and may execute instructions (or programs, code, data, etc.) stored in memory (1203) individually, collectively, or in any combination. Additionally, the processor (1202) may include a single-core processor or a multi-core processor, and in a specific implementation, may be composed of a processor assembly including a plurality of processing circuits. Additionally, it should be noted that the processor (1202) may not necessarily be composed of physical hardware when the network function (1200) is implemented in an instance form according to another embodiment.

[0325] According to one embodiment, the processor (1202) is electrically, operatively, or communicatively coupled to the network interface (1201) so as to control the network interface (1201).

[0326] The processor (1202) may include at least one processor (or processor circuitry), and at least one processor may perform the following operations individually, collectively, or in any combination. In a particular embodiment, at least one part of the processor (1202) may be included in one chip, and another part of the processor (1202) may be included in a separate chip. Alternatively, at least one processor may be included in other components, such as a network interface (1201) or memory (1203).

[0327] A processor (1202) may perform or control operations of a network entity (1200) to perform at least one or a combination thereof of methods according to embodiments of the present disclosure. For example, the processor (1202) may control operations of the network entity (1200) to exchange control plane messages or user plane messages with terminals, base stations, or other core network entities via wireless or wired communication using various protocols (e.g., NAS protocols). To this end, the processor (1202) may control other components of the network entity (1200) to perform various operations by executing computer programs, code, or instructions stored in memory (1203).

[0328] Memory (1203) is a hardware storage device capable of storing information temporarily or permanently and may include one or more storage media. For example, memory (1203) may include a memory assembly comprising one or more storage media. For example, the one or more storage media may include a hard drive, flash memory, permanent memory such as ROM (read-only memory), semipermanent memory such as RAM (random access memory), cache memory, or any combination thereof.

[0329] According to one embodiment, the memory (1203) may be electrically, operatively, or communicatively coupled to the processor (1202) and may be accessed by the processor (1202).

[0330] A computer program, code, or instruction that can be executed by a processor (1202) may be stored in the memory (1203). According to one embodiment, the computer program, code, or instruction that can be executed by the processor (1202) may be stored in a single memory or may be separated and distributed across two or more memories. The processor (1202) may perform various functions according to the embodiments of the present disclosure by executing the instruction stored in the memory (1203).

[0331] According to one embodiment of the present disclosure, the operation of a network entity (1200) may be caused to be performed based on at least one processor (or processing circuit) configured to perform the features of the present disclosure individually, collectively, or in any combination based on the execution of instructions (or computer program or code) stored in memory (1203), based on processing circuitry not configured to execute instructions, and / or based on components of a processing circuitry not configured to execute instructions.

[0332] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.< / maxnoofplmns> < / maxnoofservedguamis> < / maxnoofbplmns> < / maxnooftacs>

Claims

1. In a method of operation of a base station in a wireless communication system, A step of receiving a request message for network registration from a terminal; Based on the above request message, a step of transmitting an AMF (access and mobility management function) search request message to the NRF (network repository function); A step of receiving a plurality of AMF profile information from the above NRF; and A method comprising the step of selecting an AMF based on the above request message and the above plurality of AMF profile information.

2. In Paragraph 1, A step of transmitting a non-access stratum (NAS) message for initial connection of the terminal to the selected AMF; and A method further comprising the step of receiving a downlink NAS message from the above AMF.

3. In Paragraph 1, A method in which the above registration request message includes requested network slice selection assistance information (NSSAI) and registration type information.

4. In Paragraph 3, The above registration type information is, A method set to one of the values ​​of Initial Registration, Mobility Registration Renewal, Periodic Registration Renewal, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Renewal.

5. In Paragraph 1, If a valid GUTI (globally unique temporary identifier) ​​of the above terminal exists, the GUTI is included in the registration request message, and A method in which, if a valid GUTI of the terminal does not exist within the terminal, a SUCI (Subscription Concealed Identifier) ​​is included in the registration request message.

6. In Paragraph 1, The above AMF search request message is, A method comprising NSSAI (requested network slice selection assistance information) requested by the terminal, TAC (tracking area code) managed by the AMF being retrieved, and PLMN (public land mobile network) ID.

7. In a method of operating a terminal in a wireless communication system, A step of transmitting a request message for network registration to a base station; A step of receiving an identifier request message from an AMF selected by the base station via a network repository function (NRF) based on the above request message; The step of transmitting an identifier response message containing the identifier of the terminal to the above AMF; and A method comprising the step of receiving a registration acceptance message from the above AMF.

8. In Paragraph 7, The above registration request message includes requested NSSAI (requested network slice selection assistance information) and registration type information, and The above registration type information is, A method set to one of the values ​​of Initial Registration, Mobility Registration Renewal, Periodic Registration Renewal, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Renewal.

9. In Paragraph 7, If a valid GUTI (globally unique temporary identifier) ​​of the terminal exists, a step of including the GUTI in the registration request message; and A method further comprising the step of including a SUCI (Subscription Concealed Identifier) ​​in the registration request message when a valid GUTI of the terminal does not exist within the terminal.

10. In a base station in a wireless communication system, At least one transceiver; At least one processor connected to the above at least one transceiver so as to be able to communicate; and The base station is connected to communicate with at least one processor and is capable of executing individually or in any combination of the at least one processor, and, Receive a request message for network registration from the terminal, Based on the above request message, an AMF (access and mobility management function) search request message is transmitted to the NRF (network repository function), and Receive multiple AMF profile information from the above NRF, and A memory storing a command to select an AMF based on the above request message and the above plurality of AMF profile information; Base station including 11. In Paragraph 10, The above command, the above base station, Transmit a NAS (non-access stratum) message for initial connection of the terminal to the selected AMF, and A base station characterized by receiving downlink NAS messages from the above AMF.

12. In Paragraph 10, The above registration request message includes requested NSSAI (requested network slice selection assistance information) and registration type information, and The above registration type information is, Base station, set to one of the values ​​of Initial Registration, Mobility Registration Renewal, Periodic Registration Renewal, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Renewal.

13. In Paragraph 10, The above AMF search request message is, A base station comprising NSSAI (requested network slice selection assistance information) requested by the terminal, TAC (tracking area code) managed by the AMF being searched, and PLMN (public land mobile network) ID.

14. In a terminal in a wireless communication system, At least one transceiver; At least one processor connected to the above at least one transceiver so as to be able to communicate; and The terminal is connected to communicate with at least one processor and is capable of executing individually or in any combination of the at least one processor, so that the terminal, Send a request message for network registration to the base station, and Based on the above request message, the base station receives an identifier request message from the AMF selected via the NRF (network repository function), and Transmit an identifier response message containing the identifier of the terminal to the above AMF, and A memory storing a command to receive a registration acceptance message from the above AMF; A terminal including 15. In Paragraph 14, The above registration request message includes requested NSSAI (requested network slice selection assistance information) and registration type information, and The above registration type information is, A terminal set to one of the values ​​of Initial Registration, Mobility Registration Renewal, Periodic Registration Renewal, Emergency Registration, Disaster Roaming Initial Registration, or Disaster Roaming Mobility Registration Renewal.

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