Method and apparatus for supporting mobility and paging for UE in RRC inactive state in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. In particular, proposed in the present disclosure are a method and apparatus for improving a paging procedure and a context transfer procedure according to UE mobility in order to efficiently maintain an RRC INACTIVE state of a UE in a wireless communication system.

Description

Method and device for supporting mobility and paging for an RRC inactive state terminal in a wireless communication system

[0001] The present disclosure relates to a wireless communication system (or, mobile communication system). Specifically, the present disclosure relates to a method and apparatus for supporting mobility and paging for a terminal in a radio resource control (RRC) inactive state.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, implementation in the terahertz band (e.g., the 3 terahertz (3 THz) band at 95 GHz) is being considered to achieve transmission speeds 50 times faster and ultra-low latency reduced to one-tenth compared to 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X (Vehicle-to-Everything), which helps autonomous vehicles make driving decisions and enhance user convenience based on their own location and status information transmitted by the vehicle; NR-U (New Radio Unlicensed), which aims for system operation in unlicensed bands to comply with various regulatory requirements; NR terminal low power consumption technology (UE Power Saving); Non-Terrestrial Network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

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

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms to guarantee coverage in the terahertz band of 6G mobile communication technology, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas; metamaterial-based lenses and antennas to improve terahertz band signal coverage; high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum); and Reconfigurable Intelligent Surface (RIS) technology; as well as Full Duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] Meanwhile, with the advancement of communication systems, there is a growing demand for various improvements to the mobility and paging procedures of terminals in an RRC-inactive state.

[0009] The disclosed embodiment provides a method for transmitting the context of a terminal between base stations and a method for paging the terminal between base stations in a process in which a terminal in an RRC-inactive state moves between cells and then connects to a new base station in a mobile communication system, where there is no direct interface between base stations. To this end, the method provides a method for establishing an area (i.e., a RAN (radio access network) level area) where a terminal in an RRC-inactive state can move without a base station connection, and a method for transmitting information between base stations, such as inter-base station paging information and terminal context (UE context) information, through a connection between a base station and a core network (CN).

[0010] A method performed by a first base station according to one embodiment of the present disclosure comprises: determining a radio access network (RAN) paging area for user equipment (UE); determining, based on the RAN paging area, to request RAN paging to a second base station that is not directly connected to the first base station; and transmitting a first message to an access and mobility management function (AMF) entity to request paging to the second base station.

[0011] A method performed by an access and mobility management function (AMF) entity according to one embodiment of the present disclosure comprises: receiving a first message from a first base station to request paging to a second base station not directly connected to the first base station, based on a radio access network (RAN) paging area for user equipment (UE); and transmitting a second message to the second base station to request paging.

[0012] A first base station according to one embodiment of the present disclosure comprises: at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and at least one memory communicatively coupled to the at least one processor for storing instructions, wherein the instructions are executed individually or in any combination by the at least one processor so that the first base station: determines a radio access network (RAN) paging area for user equipment (UE), determines, based on the RAN paging area, to request RAN paging to a second base station not directly connected to the first base station, and transmits a first message to an access and mobility management function (AMF) entity to request paging to the second base station.

[0013] An access and mobility management function (AMF) entity according to one embodiment of the present disclosure comprises: at least one processor; and at least one memory that is communicationally coupled to the at least one processor and stores instructions, wherein the instructions are executed by the at least one processor individually or in any combination, so that the AMF entity: receives a first message from a first base station to request paging to a second base station not directly connected to the first base station based on a radio access network (RAN) paging area for user equipment (UE), and transmits a second message to the second base station to request paging.

[0014] According to the various embodiments proposed in the present disclosure, mobility of a terminal in an RRC-inactive state can be effectively supported in a wireless communication system.

[0015] FIG. 1 is a drawing illustrating the structure of a wireless communication system (or, mobile communication system) related to the present disclosure.

[0016] FIG. 2 is a flowchart illustrating a procedure for a base station to set a RAN-based notification area (i.e., a RAN notification area) to a terminal according to one embodiment of the present disclosure.

[0017] FIG. 3 is a flowchart illustrating a procedure for a base station to check whether to support mobility of an RRC-inactive terminal through a core network according to one embodiment of the present disclosure.

[0018] FIG. 4 is a flowchart illustrating a procedure in which, according to one embodiment of the present disclosure, a base station transmits the context of a terminal in an RRC-inactive state through a core network and the terminal maintains an RRC-inactive state.

[0019] FIG. 5 is a flowchart illustrating another procedure according to one embodiment of the present disclosure in which a base station transmits the context of a terminal in an RRC-inactive state through a core network and the terminal maintains an RRC-inactive state.

[0020] FIG. 6 is a flowchart illustrating a procedure for setting up methods related to paging transmission between a terminal and a base station according to one embodiment of the present disclosure.

[0021] FIG. 7 is a flowchart illustrating a procedure for transmitting a base station paging (i.e., RAN paging) request through an interface between base stations according to one embodiment of the present disclosure.

[0022] FIG. 8 is a drawing illustrating an example of the configuration of a RAN NODE MESSAGE FORWARD REQUEST message according to one embodiment of the present disclosure.

[0023] FIG. 9 is a drawing illustrating an example of the configuration of a RAN NODE MESSAGE FORWARD message according to one embodiment of the present disclosure.

[0024] FIG. 10 is a block diagram illustrating an example of the configuration of a base station according to one embodiment of the present disclosure.

[0025] FIG. 11 is a block diagram illustrating an example of the configuration of a terminal according to one embodiment of the present disclosure.

[0026] FIG. 12 is a block diagram of a network entity performing network functions according to one embodiment of the present disclosure.

[0027] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be 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 this specification.

[0028] 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. The embodiments provided are merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the invention, 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.

[0029] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can 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 function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function 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).

[0030] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific 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 described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0031] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an 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 within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0032] In describing the present disclosure below, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present disclosure. Embodiments of the present disclosure will be described below with reference to the attached drawings.

[0033] 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.

[0034] For convenience of explanation, the present disclosure uses terms and names defined in the 3GPP NR (3rd Generation Partnership Project NR (New Radio)) or 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standards. However, the present disclosure is not limited to the above terms and names and may be equally applied to systems conforming to other standards.

[0035] Hereinafter, a base station (BS) is an entity that performs resource allocation for terminals and may be at least one of a gNodeB (gNB), eNodeB (eNB), NodeB, a RAN (radio access network) node, a radio access unit, a base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Of course, it is not limited to the above examples.

[0036] Additionally, in this disclosure, gNB may be used interchangeably with eNB for convenience of explanation. That is, a base station described as an eNB may represent a gNB. Furthermore, the term terminal may refer to mobile phones, MTC devices, NB (narrow band)-IoT (internet of things) devices, sensors, as well as other wireless communication devices.

[0037] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0038] As a representative example of a broadband wireless communication system, the LTE system employs the Orthogonal Frequency Division Multiplexing (OFDM) method for the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method for the uplink (UL). The uplink refers to a wireless link through which a terminal (or UE) transmits data or control signals to a base station (or eNB, gNB), and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above multiple access method distinguishes the data or control information of each user by allocating and operating time-frequency resources to be transmitted for each user so that they do not overlap, that is, so that orthogonality is established.

[0039] As a future communication system following LTE, 5G communication systems must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for 5G communication systems include enhanced mobile broadband communication (eMBB), massive machine-based communication (mMTC), and ultra-reliable low-latency communication (URLLC).

[0040] According to one embodiment, eMBB may aim to provide a data transmission speed that is higher than the data transmission speed supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. In addition, the 5G communication system may need to provide a user-perceived data rate while simultaneously providing the peak data rate. To satisfy these requirements, the 5G communication system may require improvements in various transmission and reception technologies, including enhanced Multiple Input Multiple Output (MIMO) transmission technology. Furthermore, while current LTE transmits signals using a maximum transmission bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can satisfy the data transmission speed required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in frequency bands of 3 to 6 GHz or above 6 GHz.

[0041] Simultaneously, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT services, mMTC may require support for a large number of terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT devices are attached to various sensors and equipment to provide communication functions, a cell must be capable of supporting a large number of terminals (e.g., 1,000,000 terminals / km²). Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones not covered by cells, such as building basements; therefore, wider coverage may be required compared to other services provided by 5G communication systems. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace terminal batteries, a very long battery life of 10 to 15 years may be required.

[0042] Finally, URLLC is a mission-critical cellular-based wireless communication service that can be used for services such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC may need to offer very low latency and very high reliability. For example, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and may simultaneously require a packet error rate of 10^-5 or less. Consequently, for services supporting URLLC, 5G systems must provide a Transmission Time Interval (TTI) smaller than other services, and design considerations may be required to allocate wide resources in the frequency band to ensure the reliability of the communication link.

[0043] The three services considered in the aforementioned 5G communication system, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted within a single system. In this case, different transmission and reception techniques and parameters may be used between the services to satisfy the different requirements of each service. However, the aforementioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types to which the present disclosure applies are not limited to the examples mentioned above.

[0044] In addition, although embodiments of the present disclosure are described below with reference to LTE, LTE-A, LTE Pro, 5G (or NR), or 6G systems, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0045] In a mobile communication system, the connection state between a terminal and a base station is defined by the RRC (Radio Resource Control) protocol, and the terminal's state is defined by the following three RRC states.

[0046] - RRC IDLE state: A state in which the terminal is not connected to the base station via RRC. In this state, the terminal detects the base station's incoming signal, monitors the paging channel to receive core network paging (CN Paging), and obtains cell system information to independently perform neighbor cell measurement and cell selection.

[0047] - RRC Connected (or Active) State (RRC CONNECTED state): A state in which the terminal is RRC connected with the base station. The terminal transmits and receives data with the network through the base station and can perform handover between cells and base stations under the control of the base station based on the terminal's measurement result reports.

[0048] - RRC Inactive State (RRC INACTIVE state): A state in which a terminal disconnects the RRC connection after being in the RRC connected (or active) state (RRC CONNECTED state) with the base station, thereby enabling a fast RRC connection by saving some terminal context (UE context) information of the RRC connection state between the base station and the terminal. Similar to the RRC IDLE state, the terminal detects the incoming signal from the base station and monitors the paging channel to receive core network paging (CN Paging) and base station paging (RAN paging), and obtains cell system information to independently perform neighbor cell measurement and cell selection. Additionally, the terminal can check the RAN-based notification area (i.e., RNA (RAN notification area)) set by the network based on the cell system information, and if it moves out of the set RAN-based notification area, it can perform a procedure to update the RAN-based notification area to the network (i.e., RNA update (RNAU)).

[0049] For a terminal in the RRC inactive state, the last serving base station, which is the base station when the terminal changes from the RRC connected state to the RRC inactive state, can store the terminal context (UE context) information. In this case, when the terminal performs an RRC connection to the base station again and transitions to the RRC connected state, the new serving base station receives the terminal context (UE context) information from the last serving base station and uses it in the RRC connection process, so the connection time until the terminal connects to the network and transmits signal messages or user data can be reduced.

[0050] FIG. 1 is a drawing illustrating the structure of a wireless communication system (or, mobile communication system) related to the present disclosure.

[0051] FIG. 1 is a diagram illustrating an example of the structure of a mobile communication system to which the technology of this disclosure can be applied. The RAN Node (20) specified in this structure may be a base station connected to a core network (CN: Core Network) (30), and may be, for example, a 4G eNB, a 5G gNB, a 6G base station, etc. The core network (30) may be an EPC (Evolved Packet Core Network), a 5GC (5G Core Network), a 6GC (6G Core Network), etc. Some entities or functions of the core network, for example, a 4G MME (Mobility Management Entity) or a 5G AMF (Access and Mobility Management Function), establish an interface connection with the RAN Node (20). The interface (60) between the RAN Node (20) and the core network (30) may be a 4G S1 interface, a 5G NG interface, a 6G NG interface, etc. A RAN Node (20) can be connected to an interface (70) that can communicate directly with another RAN Node, and the interface (70) between RAN Nodes can be a 4G X2 interface, a 5G Xn interface, a 6G Xn interface, etc. Additionally, a RAN Node (20) may not be connected to an interface for direct communication with another RAN Node, and if there is no interface directly connected between RAN Nodes, an interface connected to the core network (30) can be used.

[0052] In order to support inter-cell movement of a terminal in the existing RRC inactive state, a direct interface (70) between base stations that are RAN Nodes is required, and context information of the terminal in the RRC inactive state can be transmitted through the direct interface (70) between base stations. Additionally, the RAN-based notification area can be configured to be limited to the cells supported by the base station that is directly connected to the last serving base station via a direct interface. Therefore, when the terminal's RRC state changes to the RRC inactive state, if there is no direct interface between the last serving base station and the base station that the terminal intends to connect to, the terminal performs a procedure (i.e., an RRC setup procedure) to transition from the RRC idle state to the RRC connected state with the new base station, thereby creating a new terminal context (UE context). And, the terminal context (UE context) stored in the last serving base station is deleted from the last serving base station in accordance with the instructions of the core network (CN) (30) which recognizes that the terminal is connected to a new base station.

[0053] The present disclosure proposes an embodiment for maintaining the RRC inactive state even when the terminal in the RRC inactive state moves to a base station that does not have a direct interface connection with the last serving base station. In addition, the present disclosure proposes a method to reduce the connection time until the terminal connects to a base station and transmits signal messages or user data by receiving terminal context (UE context) information from the last serving base station at the new serving base station and using it in the RRC connection process during the process of the terminal reconnecting to a base station and transitioning to the RRC connected state. To this end, the present disclosure proposes embodiments for setting a RAN-based notification area (RAN notification area (RNA)) for a terminal transitioning to an RRC inactive state (RRC INACTIVE state) in a network, embodiments for transmitting terminal context information between base stations using an interface connected between a base station and a core network, embodiments for controlling and determining whether to receive paging messages using core network paging (CN Paging) or base station paging (RAN paging) at a terminal and a base station, and embodiments for transmitting a base station paging (RAN paging) request between base stations using an interface connected between a base station and a core network.

[0054] FIG. 2 is a flowchart illustrating a procedure for a base station to set a RAN-based notification area (i.e., a RAN notification area (RNA)) to a terminal according to one embodiment of the present disclosure.

[0055] FIG. 2 illustrates a procedure for a core network or operator server to set RAN-based notification area information to a base station in order to set a RAN-based notification area to a terminal at a base station according to one embodiment. The RAN-based notification area information set at the base station may be set per base station or per cell supported by the base station, and terminal-specific RAN-based notification area information may be transmitted to the base station during the process of the terminal transitioning to an RRC-connected state. The RAN-based notification area information set at the base station may be set by the base station using an RRC message (e.g., an RRC Reconfiguration message) to a terminal in an RRC-connected state, or by the base station using an RRC message (e.g., an RRC release message including suspendConfig) during the procedure of the terminal transitioning to an RRC-inactive state. A RAN-based notification area (RAN notification area) set for a terminal may include a list of information such as cell identifier information (Cell Identifier), base station identifier information (RAN node Identifier), or TAC (Tracking Area Code) information. A base station may determine a RAN-based notification area (RAN notification area) set for a terminal based on information set for the base station.

[0056] Method 1-1 and Method 1-2 illustrated in FIG. 2 are methods for setting RAN-based notification area information for each base station or cell supported by the base station. Specifically, Method 1-1 is a method for managing base stations on an OAM (Operation And Management) server and setting RAN-based notification area information, and Method 1-2 is a method for the core network to set RAN-based notification area information to the base station during the process of the base station performing an interface connection with the core network (CN). Although Method 1-2 in FIG. 2 illustrates a procedure-based method for the base station to connect with the core network, the core network may also separately set RAN-based notification area information to the base station after the interface connection between the base station and the core network is completed.

[0057] In step 100 of Method 1-1, the OAM server (40) can set RAN-based notification area (RAN notification area) information for each base station or cell supported by the base station while performing processes such as setting various parameters of the base station (20). In step 200 of Method 1-2, the base station (20) transmits a Setup request message (e.g., S1 Setup Request message or NG Setup Request message) to the core network (30) for interface connection with the core network (30). In step 210, the core network (30) transmits a Setup request response message (e.g., S1 Setup Response message or NG Setup Response message) to the base station (20), and can include RAN-based notification area (RAN notification area) information for each base station or cell supported by the base station in the Setup request response message. After the base station (20) and the core network (30) complete the interface connection between each other, they can set RAN-based notification area (RAN notification area) information for each base station or cell supported by the base station using a Configuration Update message, etc.

[0058] Method 2 illustrated in FIG. 2 is a method for setting RAN-based notification area (RAN notification area) information for each terminal. When the terminal (10) performs an RRC connection procedure with the base station (20) in step 300, the base station (20) can transmit an Initial UE Message to the core network (30) to indicate that the terminal is performing the RRC connection procedure. Accordingly, in step 310, the core network (30) transmits an Initial Context Setup Request message containing information for setting the terminal context (UE context) to the base station (20), and can include RAN-based notification area (RAN notification area) information to be set for the terminal in the Initial Context Setup Request message. Even when the terminal is in an RRC active state (RRC CONNECTED state), the core network (30) may update and transmit the RAN-based notification area (RAN notification area) information to be set for the terminal to the base station (20) using a predetermined message such as a UE Context Modification Request message or a Path Switch Request Acknowledge message.

[0059] FIG. 3 is a flowchart illustrating a procedure for a base station to check whether to support mobility of an RRC-inactive terminal through a core network according to one embodiment of the present disclosure.

[0060] FIG. 3 is a flowchart of a procedure for determining whether mobility of an RRC inactive terminal can be supported using an interface connected between a base station and a core network. Method 1-1 illustrated in FIG. 3 is a method in which an OAM (Operation And Management) server configures the base station to support mobility of an RRC inactive terminal using an interface connected between the base station and the core network. Method 1-2 illustrated in FIG. 3 is a method in which, during the process of the base station setting up an interface connection with the core network (CN), the core network is configured to support mobility of an RRC inactive terminal using an interface connected between the base station and the core network. Although Method 1-2 illustrates a procedure-based method in which the base station connects to the core network, it is also possible to configure the core network to support mobility of an RRC inactive terminal using an interface connected between the base station and the core network through additional procedures between the core network and the base station after the interface connection between the base station and the core network is completed.

[0061] In step 100 of Method 1-1 of FIG. 3, the OAM server (40) performs the process of setting various parameters of the base station (20), and can transmit information that supports the mobility of a terminal in an RRC inactive state using an interface connected between the base station and the core network, such as a RAN Node Message Forward Allowed Indicator. In step 200 of Method 1-2 of FIG. 3, the base station (20) transmits a Setup Request message (e.g., S1 Setup Request message or NG Setup Request message) to the core network (30) for interface connection with the core network (30), and can transmit information that supports the mobility of a terminal in an RRC inactive state using an interface connected between the base station and the core network, such as a RAN Node Message Forward Supported Indicator. In step 210, the core network (30) transmits a Setup request response message (e.g., S1 Setup Response message or NG Setup Response message) to the base station (20), and the Setup request response message may include information to support the mobility of a terminal in an RRC inactive state using the interface connected between the base station and the core network, such as, for example, a RAN Node Message Forward Supported Indicator (or RAN Node Message Forward Allowed Indicator). After the base station (20) and the core network (30) complete the interface connection between each other, they may set the information to support the mobility of a terminal in an RRC inactive state using the interface connected between the base station and the core network using a Configuration Update message, etc.

[0062] FIG. 4 is a flowchart illustrating a procedure in which, according to one embodiment of the present disclosure, a base station transmits the context of a terminal in an RRC-inactive state through a core network and the terminal maintains an RRC-inactive state.

[0063] The embodiment of FIG. 4 describes a case where a terminal in an RRC inactive state moves to a base station that is not directly interfaced with the last serving base station and is not included in the RAN-based notification area configured for the terminal. FIG. 4 describes operations to maintain the terminal in an RRC inactive state by, in the above-described situation, transmitting the terminal context (UE Context) of the RRC inactive state terminal through an interface with the core network and resetting the terminal's RAN-based notification area.

[0064] In step 100 of FIG. 4, the terminal in the RRC active state (RRC CONNECTED state) connects to the network and transmits and receives signals, messages, and / or user data while the RRC connection is established with the RAN Node 1 (20) base station. Subsequently, if there is no user data to transmit to the terminal, in step 200, the RAN Node 1 (20) can release the RRC connection by sending an RRC Release message to the terminal (10). In order to keep the terminal (10) in the RRC inactive state (RRC INACTIVE state) in step 200, the RAN Node 1 (20) instructs the terminal (10) to maintain the terminal context (UE Context) information while transitioning to the RRC inactive state (RRC INACTIVE state) by transmitting information such as a Suspend Indicator (or suspendConfig parameter) in the RRC Release message. Additionally, RAN Node 1 (20) can also maintain terminal context (UE Context) information after sending an RRC Release message to the terminal and operate as the last serving base station of the terminal (10). RAN Node 1 (20) can set up a RAN-based notification area (RAN notification area) for the terminal using an RRC message, for example, an RRCReconfiguration message, in step 100, and can also set up a RAN-based notification area (RAN notification area) for the terminal using an RRC Release message sent to the terminal in step 200.

[0065] In step 300, after the terminal (10) moves out of the cell area of ​​the RAN Node 1 (20) base station and into the cell area of ​​the RAN Node 2 (25) base station, the terminal (10) can detect that it has changed cells and moved out of the RAN-based notification area (RAN notification area) set for the terminal based on system information transmitted from the cell of the RAN Node 2 (25) base station. Accordingly, in step 310, the terminal (10) transmits an RRC message, for example, a ResumeRequest message, to the RAN Node 2 (25). The RRC message transmitted in step 310 may include an indicator or information indicating that the terminal has left the RAN-based notification area (RAN notification area) and requires an update, for example, a RAN notification area update indicator (i.e., RNAU indicator); additionally, it may include identifier information set to distinguish the terminal at the last serving base station, for example, I-RNTI (Inactive Radio Network Temporary Identifier), identifier information set to distinguish the terminal in the core network, for example, GUTI (Global Temporary UE ID), and may also include identifier information of the last serving base station.

[0066] In step 310, RAN Node 2 (25), having received an RRC ResumeRequest message from the terminal (10), can determine a core network entity or function based on the GUTI information transmitted by the terminal. Subsequently, in step 320, RAN Node 2 (25) transmits a message to the core network (30), for example, a RAN Node Message Forward Request message, to request message forwarding to the last serving base station in order to request the terminal context (i.e., UE context) from the last serving base station through the core network (30). The RAN Node Message Forward Request message may include the GUTI information transmitted by the terminal and may further include source RAN Node ID information transmitting the RAN Node Message Forward Request message and target RAN Node ID information receiving it. In this embodiment, the RAN Node Message Forward Request message in step 320 may include identifier information of RAN Node 2 (25) as the source RAN Node ID and identifier information of RAN Node 1 (20), the last serving base station, as the target RAN Node ID. The RAN Node Message Forward Request message in step 320 may further include information or base station messages for a terminal context (UE Context) request, for example, Retrieve UE Context Request information or messages, and the Retrieve UE Context Request information or messages may include I-RNTI information for identifying the terminal at the last serving base station transmitted by the terminal (10).

[0067] In step 320, the core network (30), having received a RAN Node Message Forward Request message from RAN Node 2 (25), can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. In step 330, the core network (30) transmits a message to RAN Node 1 (20), for example, a RAN Node Message Forward message, to deliver the information or message received from RAN Node 2 (25). The RAN Node Message Forward message in step 330 may include a Source RAN Node ID to identify the base station that transmitted the message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 330 may include identifier information of RAN Node 2 (25). The RAN Node Message Forward message in step 330 may also include information for a terminal context (UE Context) request or a base station message, for example, Retrieve UE Context Request information or a message, and the Retrieve UE Context Request information or a message may include I-RNTI information for identifying the terminal at the last serving base station.

[0068] RAN Node 1 (20), having received a RAN Node Message Forward message from the core network (30) in step 330, can confirm a request for terminal context (UE Context) delivery based on the information included in the RAN Node Message Forward message, and in step 340, the terminal transmits a message to the core network (30) to deliver the terminal's context (UE Context), for example, a RAN Node Message Forward Request message. The RAN Node Message Forward Request message may include source RAN Node ID information for transmitting the RAN Node Message Forward Request message and target RAN Node ID information for receiving it. The RAN Node Message Forward Request message in step 340 may include identifier information of RAN Node 1 (20) as the source RAN Node ID and identifier information of RAN Node 2 (25) as the target RAN Node ID. The RAN Node Message Forward Request message in step 340 may further include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include terminal context (UE context) information.

[0069] In step 340, the core network (30) that receives a RAN Node Message Forward Request message from RAN Node 1 (20) can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message, and in step 350, the core network (30) transmits a message to deliver the information or message received from RAN Node 1 (20), for example, a RAN Node Message Forward message, to RAN Node 2 (25). The RAN Node Message Forward message in step 350 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 350 may include identifier information of RAN Node 1 (20). The RAN Node Message Forward message in step 350 may also include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include information of the terminal context (UE context).

[0070] At step 350, RAN Node 2 (25), having received terminal context (UE context) information from the last serving base station, transmits a Path Switch Request message to change the path for data transmission of the terminal to RAN Node 2 (25) in step 400, and receives a Path Switch Request Acknowledge message from the core network (30) in step 410, which is a response message regarding the path change for data transmission of the terminal. Subsequently, RAN Node 2 (25) determines or sets a new RAN-based notification area (RAN notification area) for the terminal (10), and in order to keep the terminal (10) in an RRC inactive state (RRC INACTIVE state) in step 500, transmits Suspend Indicator information (or suspendConfig parameter) to the terminal (10) in an RRC Release message, thereby instructing or setting the terminal (10) to maintain the terminal context (UE Context) information while transitioning to an RRC inactive state (RRC INACTIVE state). In addition, RAN Node 2 (250) also maintains the terminal context (UE Context) information after sending an RRC Release message to the terminal, and operates as the new last serving base station of the terminal (10). Also, the RRC Release message sent to the terminal in step 500 may include a RAN-based notification area (RAN notification area).

[0071] FIG. 5 is a flowchart illustrating another procedure according to one embodiment of the present disclosure in which a base station transmits the context of a terminal in an RRC-inactive state through a core network and the terminal maintains an RRC-inactive state.

[0072] In the embodiment of FIG. 5, a case is described in which a terminal in an RRC inactive state moves to a base station that is not directly interfaced with the last serving base station and is not included in the RAN-based notification area configured for the terminal. FIG. 5 describes operations to maintain the terminal in an RRC inactive state by the base station transmitting the terminal context (UE Context) of the RRC inactive state terminal through an interface with the core network and resetting the terminal's RAN-based notification area in the above-described situation. The new base station to be connected to the terminal and the last serving base station of FIG. 5 may each be connected to another entity or function of the core network (e.g., another MME or another AMF). For example, the case in which there is a connection between other entities or functions of the core network may include a connection with another MME or a connection with another AMF.

[0073] In step 100 of FIG. 5, the terminal in the RRC active state (RRC CONNECTED state) connects to the network and transmits and receives signals, messages, and / or user data while the RRC connection is established with the RAN Node 1 (20) base station. Subsequently, if there is no user data to transmit to the terminal, in step 200, the RAN Node 1 (20) can release the RRC connection by sending an RRC Release message to the terminal (10). In order to keep the terminal (10) in the RRC inactive state (RRC INACTIVE state) in step 200, the RAN Node 1 (20) instructs the terminal (10) to maintain the terminal context (UE Context) information while transitioning to the RRC inactive state (RRC INACTIVE state) by transmitting information such as a Suspend Indicator (or suspendConfig parameter) in the RRC Release message. Additionally, RAN Node 1 (20) can also maintain terminal context (UE Context) information after sending an RRC Release message to the terminal and operate as the last serving base station of the terminal (10). RAN Node 1 (20) can set up a RAN-based notification area (RAN notification area) for the terminal using an RRC message, for example, an RRCReconfiguration message, in step 100, and can also set up a RAN-based notification area (RAN notification area) for the terminal using an RRC Release message sent to the terminal in step 200.

[0074] In step 300, after the terminal (10) moves out of the cell area of ​​the RAN Node 1 (20) base station and into the cell area of ​​the RAN Node 2 (25) base station, the terminal (10) can detect that it has changed cells and moved out of the RAN-based notification area (RAN notification area) set for the terminal based on system information transmitted from the cell of the RAN Node 2 (25) base station. Accordingly, in step 310, the terminal (10) sends an RRC message, for example, a ResumeRequest message, to the RAN Node 2 (25). The RRC message transmitted in step 310 may include an indicator or information indicating that the terminal has left the RAN-based notification area (RAN notification area) and requires an update, for example, a RAN notification area update indicator (i.e., RNAU indicator); additionally, it may include identifier information set to distinguish the terminal at the last serving base station, for example, I-RNTI (Inactive Radio Network Temporary Identifier), identifier information set to distinguish the terminal in the core network, for example, GUTI (Global Temporary UE ID), and may also include identifier information of the last serving base station.

[0075] In step 310, RAN Node 2 (25), having received an RRC ResumeRequest message from the terminal (10), can determine a core network entity or function based on the GUTI information transmitted by the terminal. Subsequently, in step 320, RAN Node 2 (25) transmits a message to the core network function 2 (35), for example, a RAN Node Message Forward Request message, to request message forwarding to the last serving base station in order to request the terminal context (i.e., UE context) from the last serving base station through the core network function 2 (35). The RAN Node Message Forward Request message may include the GUTI information transmitted by the terminal and may further include source RAN Node ID information transmitting the RAN Node Message Forward Request message and target RAN Node ID information receiving it. In this embodiment, the RAN Node Message Forward Request message in step 320 may include identifier information of RAN Node 2 (25) as the source RAN Node ID and identifier information of RAN Node 1 (20), the last serving base station, as the target RAN Node ID. The RAN Node Message Forward Request message in step 320 may further include information or base station messages for a terminal context (UE Context) request, for example, Retrieve UE Context Request information or messages, and the Retrieve UE Context Request information or messages may include I-RNTI information for identifying the terminal at the last serving base station transmitted by the terminal (10).

[0076] In step 320, the core network function 2 (35), having received a RAN Node Message Forward Request message from RAN Node 2 (25), can identify the core network entity or function (e.g., MME or AMF) that was servicing the terminal (10) along with the terminal (10) based on the GUTI or Target RAN Node ID transmitted by the terminal (10) that is included in the RAN Node Message Forward Request message. Subsequently, in step 325, the core network function 2 (35) transmits a message for requesting message delivery to the last serving base station, e.g., a RAN Node Message Forward Request message, to the core network function 1 (30) in order to request the terminal context (UE context) from the last serving base station through the core network function 1 (30).

[0077] In step 325, the core network function 1 (30), having received a RAN Node Message Forward Request message from the core network function 2 (35), can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. In step 330, the core network function 1 (30) transmits a message to convey the information or message received from the core network function 2 (35), for example, a RAN Node Message Forward message, to RAN Node 1 (20). The RAN Node Message Forward message in step 330 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 330 may include identifier information of RAN Node 2 (25). The RAN Node Message Forward message in step 330 may also include information for a terminal context (UE Context) request or a base station message, for example, Retrieve UE Context Request information or a message, and the Retrieve UE Context Request information or a message may include I-RNTI information for identifying the terminal at the last serving base station.

[0078] RAN Node 1 (20), having received a RAN Node Message Forward message from the core network function 1 (30) in step 330, can confirm a request for terminal context (UE Context) delivery based on the information included in the RAN Node Message Forward message, and in step 340, transmits a message to the core network function 1 (30) to deliver the terminal context (i.e., UE Context), for example, a RAN Node Message Forward Request message. The RAN Node Message Forward Request message may include source RAN Node ID information for transmitting the RAN Node Message Forward Request message and target RAN Node ID information for receiving it. The RAN Node Message Forward Request message in step 340 may include identifier information of RAN Node 1 (20) as the source RAN Node ID and identifier information of RAN Node 2 (25) as the target RAN Node ID. The RAN Node Message Forward Request message in step 340 may also include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include terminal context (UE context) information.

[0079] In step 340, the core network function 1 (30), having received a RAN Node Message Forward Request message from RAN Node 1 (20), can determine the core network entity or function to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message, and in step 345, the core network function 1 (30) transmits a message to the core network function 2 (35), for example, a RAN Node Message Forward message, to deliver the information or message received from RAN Node 1 (20).

[0080] In step 345, the core network function 2 (35), having received a RAN Node Message Forward Request message from the core network function 1 (30), can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. Subsequently, in step 350, the core network function 2 (35) transmits a message to convey the information or message received from the core network function 1 (30), for example, a RAN Node Message Forward message, to RAN Node 2 (25). The RAN Node Message Forward message in step 350 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 350 may include identifier information of RAN Node 1 (20). The RAN Node Message Forward message in step 350 may also include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include terminal context (UE context) information.

[0081] At step 350, RAN Node 2 (25), having received terminal context (UE context) information from the last serving base station, sends a Path Switch Request message to the core network function 2 (35) at step 400 to change the path for the terminal's data transmission to RAN Node 2 (25). At step 405, the core network function 2 (35) sends a message requesting the core network's terminal information to the core network function 1 (30), for example, a CN-level UE Context Transfer Request message, and at step 407, the core network function 1 (30) sends a response message containing the core network's terminal information, for example, a CN-level UE Context Transfer message, to the core network function 2 (35). At step 410, a Path Switch Request Acknowledge message, which is a response message regarding the path change for the terminal's data transmission, is received from the core network function 2 (35). RAN Node 2 (25) determines or sets a new RAN-based notification area (RAN notification area) for the terminal (10) and, in order to keep the terminal (10) in an RRC inactive state (RRC INACTIVE state) at step 500, transmits Suspend Indicator information (or suspendConfig parameter) to the terminal (10) in an RRC Release message, thereby instructing or setting the terminal (10) to maintain its terminal context (UE Context) information while transitioning to an RRC inactive state (RRC INACTIVE state). Additionally, RAN Node 2 (250) also maintains its terminal context (UE Context) information after transmitting an RRC Release message to the terminal and operates as the new last serving base station for the terminal (10).In addition, the RRC Release message transmitted to the terminal in step 500 may include a RAN-based notification area (RAN notification area).

[0082] FIG. 6 is a flowchart illustrating a procedure for setting up methods related to paging transmission between a terminal and a base station according to one embodiment of the present disclosure.

[0083] FIG. 6 is a flowchart of a process for configuring a method for transmitting / receiving paging messages using core network paging (CN Paging) or base station paging (RAN paging) between a terminal and a base station. The paging method configured at the base station may be configured per base station or per cell supported by the base station, or per terminal. The paging method configured by the base station may be configured for the terminal through system information, or the paging method may be configured using RRC messages transmitted to the terminal. The base station may determine the paging method for each terminal based on the information configured at the base station. As an example, the method for paging to the terminal may be configured to use RAN paging, which initiates the paging procedure at the base station, CN paging, which initiates the paging procedure at the core network, or both RAN paging and CN paging methods.

[0084] Method 1-1 and Method 1-2 included in Fig. 6 are methods for setting paging method information for each base station or cell supported by the base station. Specifically, Method 1-1 is a method for setting a paging method on an OAM (Operation And Management) server, and Method 1-2 is a method for setting a paging method from the core network to the base station during the process of the base station establishing an interface connection with the core network (CN). Although Method 1-2 illustrates a procedure-based method for the base station establishing a connection with the core network, the core network may also separately set paging method information to the base station after the base station and the core network have completed the interface connection.

[0085] In step 100 of Method 1-1, the OAM server (40) can set paging method information for each base station or cell supported by the base station while performing processes such as setting various parameters of the base station (20). In step 200 of Method 1-2, the base station (20) transmits a Setup request message for interface connection with the core network (30), for example, an S1 Setup Request message or an NG Setup Request message, to the core network (30). In step 210, the core network (30) transmits a Setup request response message, for example, an S1 Setup Response message or an NG Setup Response message, to the base station (20), and can include paging method information for each base station or cell supported by the base station in the Setup request response message. After the base station (20) and the core network (30) complete the interface connection between each other, they can set paging method information for each base station or cell supported by the base station using a Configuration Update message, etc.

[0086] Method 2 illustrated in FIG. 6 is a method for setting paging method information for each terminal. When the terminal (10) performs an RRC connection procedure with the base station (20) in step 300, the base station (20) can transmit an Initial UE Message to the core network (30) to indicate that the terminal is performing the RRC connection procedure. Accordingly, in step 310, the core network (30) transmits an Initial Context Setup Request message containing information for setting the terminal context (UE context) to the base station (20), and can include paging method information to be set for the terminal in the Initial Context Setup Request message. Even when the terminal is in an RRC active state (RRC CONNECTED state), the core network (30) may update and transmit paging method information to be set for the terminal to the base station (20) using a predetermined message such as a UE Context Modification Request message or a Path Switch Request Acknowledge message.

[0087] After a paging method is set in the base station (20), the base station (20) may set a paging method in the terminal (10) using RRC system information as in step 400, or the base station (20) may set a paging method in the terminal using a terminal-specific RRC message, for example, an RRCReconfiguration message, as in step 450.

[0088] FIG. 7 is a flowchart illustrating a procedure for transmitting a base station paging (i.e., RAN paging) request through an interface between base stations according to one embodiment of the present disclosure.

[0089] Figure 7 is a flowchart of the operation of a terminal connecting to a network by transmitting a base station paging (RAN paging) request between base stations using an interface connected between a base station and a core network.

[0090] In step 100 of FIG. 7, the terminal in the RRC active state (RRC CONNECTED state) connects to the network and transmits and receives signals, messages, and / or user data while the RRC connection is established with the RAN Node 1 (20) base station. Subsequently, if there is no user data to transmit to the terminal, the RAN Node 1 (20) can release the RRC connection by sending an RRC Release message to the terminal (10) in step 200. In order to keep the terminal (10) in the RRC inactive state (RRC INACTIVE state) in step 200, the RAN Node 1 (20) instructs the terminal (10) to maintain the terminal context (UE Context) information while transitioning to the RRC inactive state (RRC INACTIVE state) by transmitting information such as a Suspend Indicator (or suspendConfig parameter) in the RRC Release message. Additionally, RAN Node 1 (20) can also maintain terminal context (UE Context) information after sending an RRC Release message to the terminal and operate as the last serving base station of the terminal (10). RAN Node 1 (20) can set up a RAN-based notification area (RAN notification area) for the terminal using an RRC message, for example, an RRCReconfiguration message, in step 100, and can also set up a RAN-based notification area (RAN notification area) for the terminal using an RRC Release message sent to the terminal in step 200.

[0091] In step 300, when a signaling message or user data to be transmitted from the core network (30) to the terminal (10) is transmitted to the RAN Node 1 (20), in step 310, the RAN Node 1 (20) transmits a paging message to the cell where the terminal was located or to some or all of the cells supported by the RAN Node 1 (20), and waits for an RRC message for a certain period of time from the terminal corresponding to the paging message. If RAN paging for the terminal fails as in step 310, that is, if the RAN Node 1 (20) does not receive an RRC message from the terminal for a certain period of time after transmitting the paging message, in step 320, the RAN Node 1 (20) determines the next area to transmit paging. The determination of the paging area at the base station may be performed based on information transmitted to the base station along with the paging method and settings, as in the embodiment of FIG. 6. When RAN Node 1 (20) determines a paging area in step 320, RAN Node 1 (20) transmits a Paging message through a direct interface to a base station included in the determined paging area that has a direct interface connection established with RAN Node 1 (20). For base stations included in the paging area that do not have a direct interface connection with RAN Node 1 (20), in step 410, RAN Node 1 (20) transmits a message to the core network (30) to request message transmission to another base station, such as a RAN Node Message Forward Request message, in order to transmit a Paging message to the base stations included in the paging area through the core network (30).The RAN Node Message Forward Request message may include source RAN Node ID information transmitting the RAN Node Message Forward Request message and target RAN Node ID information which is information of the receiving base stations. The RAN Node Message Forward Request message in step 320 may include identifier information of RAN Node 1 (20) as the source RAN Node ID, and at least identifier information of RAN Node 2 (25), which is the base station to receive the Paging message, as the target RAN Node ID. The RAN Node Message Forward Request message in step 320 may also include information or base station messages necessary to transmit the RRC Paging message to the terminal, for example, Paging Request information or messages.

[0092] In step 410, the core network (30), having received a RAN Node Message Forward Request message from RAN Node 1 (20), can determine the base stations to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. Subsequently, in step 420, the core network (30) transmits a message for delivering information or messages received from RAN Node 1 (20), for example, a RAN Node Message Forward message, to at least one base station (or RAN Node), including RAN Node 2 (25). The RAN Node Message Forward message in step 420 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 330 may include identifier information of RAN Node 1 (20). The RAN Node Message Forward message in step 420 may also include information or base station messages necessary to transmit an RRC Paging message to a terminal, for example, Paging Request information or messages.

[0093] RAN Node 2 (25), which receives the Paging request message in step 420, transmits an RRC Paging message to the terminal (10) in step 500. The terminal (10), which receives the RRC Paging message in step 500, transmits an RRC message, for example, a ResumeRequest message, to RAN Node 2 (25) in step 510. The RRC message transmitted by the terminal (10) in step 510 may include identifier information set to distinguish the terminal at the last serving base station, for example, I-RNTI (Inactive Radio Network Temporary Identifier), identifier information set to distinguish the terminal at the core network, for example, GUTI (Global Temporary UE ID), and may further include identifier information of the last serving base station.

[0094] In step 510, RAN Node 2 (25), having received an RRC ResumeRequest message from the terminal (10), can determine a core network entity or function based on the GUTI information transmitted by the terminal. Subsequently, in step 520, RAN Node 2 (25) transmits a message to the core network (30), for example, a RAN Node Message Forward Request message, to request message delivery to the last serving base station in order to request a terminal context (UE context) from the last serving base station through the core network (30). The RAN Node Message Forward Request message may include the GUTI information transmitted by the terminal and may include source RAN Node ID information transmitting the RAN Node Message Forward Request message and target RAN Node ID information receiving it. The RAN Node Message Forward Request message in step 320 may include identifier information of RAN Node 2 (25) as the source RAN Node ID and identifier information of RAN Node 1 (20), the last serving base station, as the target RAN Node ID. The RAN Node Message Forward Request message in step 520 may further include information for a terminal context (UE Context) request or base station message, for example, Retrieve UE Context Request information or message, and the Retrieve UE Context Request information or message may further include I-RNTI information for identifying the terminal at the last serving base station transmitted by the terminal (10).

[0095] In step 520, the core network (30), having received a RAN Node Message Forward Request message from RAN Node 2 (25), can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. Subsequently, in step 530, the core network (30) transmits a message to RAN Node 1 (20), for example, a RAN Node Message Forward message, to deliver the information or message received from RAN Node 2 (25). The RAN Node Message Forward message in step 530 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 530 may include identifier information of RAN Node 2 (25). In step 530, the RAN Node Message Forward message may further include information for a terminal context (UE Context) request or base station message, for example, Retrieve UE Context Request information or message, and the Retrieve UE Context Request information or message may further include I-RNTI information for identifying the terminal at the last serving base station.

[0096] RAN Node 1 (20), having received a RAN Node Message Forward message from the core network (30) in step 530, can confirm a request for terminal context (UE Context) delivery based on the information included in the RAN Node Message Forward message, and in step 540, can send a message to the core network (30), for example, a RAN Node Message Forward Request message, to deliver the terminal context (UE Context). The RAN Node Message Forward Request message may include source RAN Node ID information for sending the RAN Node Message Forward Request message and target RAN Node ID information for receiving it. The RAN Node Message Forward Request message in step 540 may include identifier information of RAN Node 1 (20) as the source RAN Node ID and identifier information of RAN Node 2 (25) as the target RAN Node ID. The RAN Node Message Forward Request message in step 540 may also include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include terminal context (UE context) information.

[0097] In step 540, the core network (30), having received a RAN Node Message Forward Request message from RAN Node 1 (20), can determine the base station to which the message will be delivered based on the target RAN Node ID information included in the RAN Node Message Forward Request message. In step 550, the core network (30) transmits a message to RAN Node 2 (25), for example, a RAN Node Message Forward message, to deliver the information or message received from RAN Node 1 (20). The RAN Node Message Forward message in step 550 may include a Source RAN Node ID to identify the base station that transmitted this message, and the Source RAN Node ID included in the RAN Node Message Forward message in step 550 may include identifier information of RAN Node 1 (20). The RAN Node Message Forward message in step 550 may also include information or base station messages for a response to a terminal context (UE Context) request, for example, Retrieve UE Context Response information or messages, and the Retrieve UE Context Response information or messages may include terminal context (UE context) information.

[0098] RAN Node 2 (25), having received terminal context (UE context) information from the last serving base station at step 550, can send a Path Switch Request message to the core network (30) at step 600 to change the path for data transmission of the terminal to RAN Node 2 (25), and at step 610, receives a Path Switch Request Acknowledge message from the core network (30) as an acknowledgment message regarding the path change for data transmission of the terminal. Subsequently, at step 700, RAN Node 2 (25) can modify the RRC connection by sending an RRC message to the terminal (10) to change the RRC connection settings, for example, an RRC Reconfiguration message, and can transmit and receive signals, messages, and / or user data with the terminal in the RRC active state (RRC CONNECTED state).

[0099] FIG. 8 is a drawing illustrating an example of the configuration of a RAN NODE MESSAGE FORWARD REQUEST message according to one embodiment of the present disclosure.

[0100] FIG. 8 illustrates an example of the configuration of a RAN NODE MESSAGE FORWARD REQUEST message transmitted from a base station to a core network through an interface between a base station and a core network, such as an S1 interface or an NG interface, as described in steps 320 and 340 of FIG. 4, steps 320 and 340 of FIG. 5, and / or steps 410, 520, and 540 of FIG. 7. The names of the messages or IE included in FIG. 8 are merely examples and other names for the same function may be used, and the information and parameters included in FIG. 8 may be included in messages with different names or other messages and used for the purposes proposed in this disclosure.

[0101] According to one embodiment illustrated in FIG. 8, the RAN NODE MESSAGE FORWARD REQUEST message includes a Message Type IE used to distinguish message types and other parameters and / or IEs. Additionally, the RAN NODE MESSAGE FORWARD REQUEST message may include a Source RAN Node ID IE containing identifier information of a base station (i.e., RAN Node) transmitting the RAN NODE MESSAGE FORWARD REQUEST message, and a Target RAN Node IDs IE containing identifier information of base stations (i.e., RAN Nodes) receiving the RAN NODE MESSAGE FORWARD REQUEST message. The Target RAN Node IDs IE may include identifier information of one or more base stations (RAN Nodes). The RAN NODE MESSAGE FORWARD REQUEST message may include a UE Information IE containing terminal-related information, and the UE Information IE may include GUTI (Global Temporary UE ID) information, which is identifier information set to distinguish terminals in the core network. The RAN NODE MESSAGE FORWARD REQUEST message may include base station message-related information for direct transmission between base stations. According to one embodiment, the base station message-related information may include an Inter-RAN Message IE containing messages used in the direct interface between base stations, and may also include a separate IE for each base station message (e.g., UE Context Retrieval Request IE, UE Context Retrieval Response IE, Paging IE, etc.).It goes without saying that the RAN NODE MESSAGE FORWARD REQUEST message can include not only base station messages that can be transmitted between other base stations not included in FIG. 8, but also other information.

[0102] FIG. 9 is a drawing illustrating an example of the configuration of a RAN NODE MESSAGE FORWARD message according to one embodiment of the present disclosure.

[0103] FIG. 9 illustrates an example of the configuration of a RAN NODE MESSAGE FORWARD message transmitted from a core network to a base station through an interface between a base station and a core network, such as an S1 interface or an NG interface, as described in steps 330 and 350 of FIG. 4, steps 330 and 350 of FIG. 5, and / or steps 420, 530, and 550 of FIG. 7. The names of the messages or IE included in FIG. 9 are merely examples and other names for the same function may be used, and the information and parameters included in FIG. 9 may be included in messages with different names or other messages and used for the purposes proposed in this disclosure.

[0104] According to one embodiment illustrated in FIG. 9, the RAN NODE MESSAGE FORWARD message includes a Message Type IE used to distinguish message types and other parameters and / or IEs. Additionally, the RAN NODE MESSAGE FORWARD message may include a Source RAN Node ID IE containing identifier information of the base station (i.e., RAN Node) transmitting the RAN NODE MESSAGE FORWARD message. The RAN NODE MESSAGE FORWARD message may include a UE Information IE containing terminal-related information. The RAN NODE MESSAGE FORWARD message may include base station message-related information for direct delivery to the base station. According to one embodiment, the base station message-related information may include an Inter-RAN Message IE containing messages used in the direct interface between base stations, and may also include separate IEs for each base station message (e.g., UE Context Retrieval Request IE, UE Context Retrieval Response IE, Paging IE, etc.). The RAN NODE MESSAGE FORWARD message can, of course, include not only base station messages that can be transmitted between other base stations not included in FIG. 9, but also other information.

[0105] FIG. 10 is a block diagram illustrating an example of the configuration of a base station according to one embodiment of the present disclosure.

[0106] FIG. 10 is a block diagram showing an example of the configuration of a RAN Node (i.e., a base station) according to an embodiment of the present disclosure. As shown in the figure, the RAN Node is configured to include an RF processing unit (10), a baseband processing unit (20), a backhaul communication unit (30), a storage unit (40), and a control unit (50). When the RAN Node is separated into a CU (Central Unit) and a DU (Distributed Unit), a block diagram different from that included in FIG. 10 may be configured. For example, the RF processing unit (10) and the baseband processing unit (20) may be configured to include a control unit, a storage unit, and a backhaul communication unit for communication with the CU in the DU, and for example, the backhaul communication unit (30) may be configured to include a control unit, a storage unit, and a backhaul communication unit for communication with the DU in the CU.

[0107] The RF processing unit (10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (10) upconverts the baseband signal provided by the baseband processing unit (20) into an RF band signal, transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although only one antenna is shown in the drawing, the first connection node may be equipped with multiple antennas. Additionally, the RF processing unit (10) may include multiple RF chains. Furthermore, the RF processing unit (10) may perform beamforming. For beamforming, the RF processing unit (10) may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The above RF processing unit can perform down-to-down MIMO operation by transmitting one or more layers.

[0108] The baseband processing unit (20) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence. In addition, when receiving data, the baseband processing unit (20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (10). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT operation and CP insertion. Additionally, upon receiving data, the baseband processing unit (20) divides the baseband signal provided by the RF processing unit (10) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operations, and then restores the received bit sequence through demodulation and decoding. The baseband processing unit (20) and the RF processing unit (10) transmit and receive signals as described above. Accordingly, the baseband processing unit (20) and the RF processing unit (10) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a communication unit, or a wireless communication unit.

[0109] The backhaul communication unit (30) provides an interface for communicating with other nodes within the network. The backhaul communication unit (30) converts a bit sequence transmitted from the main RAN Node to other nodes, such as an auxiliary base station or a core network, into a physical signal, and converts a physical signal received from the other nodes into a bit sequence.

[0110] The storage unit (40) stores data such as basic programs, application programs, and configuration information for the operation of the main RAN Node. In particular, the storage unit (40) can store information regarding bearers assigned to connected terminals, measurement results reported from connected terminals, etc. Additionally, the storage unit (40) can store information serving as a criterion for determining whether to provide or disconnect multiple connections to the terminals. Furthermore, the storage unit (40) provides the stored data upon a request from the control unit (50).

[0111] The control unit (50) controls the overall operations of the RAN Node. For example, the control unit (50) transmits and receives signals through the baseband processing unit (20) and the RF processing unit (10) or through the backhaul communication unit (30). Additionally, the control unit (50) writes and reads data to and from the storage unit (40). To this end, the control unit (50) may include at least one processor. Additionally, the control unit (50) may be used to control the overall operations of the RAN Node. Additionally, the control unit (50) may include a multiple connection processing unit (52) to support multiple connections.

[0112] FIG. 11 is a block diagram illustrating an example of the configuration of a terminal according to one embodiment of the present disclosure.

[0113] FIG. 11 is a block diagram illustrating an example of the structure of a terminal (UE) according to an embodiment of the present disclosure. Referring to the drawing, the terminal includes an RF (Radio Frequency) processing unit (10), a baseband processing unit (20), a storage unit (30), and a control unit (40). The RF processing unit (10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (10) up-converts a baseband signal provided by the baseband processing unit (20) into an RF band signal and transmits it through an antenna, and down-converts an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), etc. Although only one antenna is shown in the drawing, the terminal may be equipped with multiple antennas. Additionally, the RF processing unit (10) may include a plurality of RF chains. Furthermore, the RF processing unit (10) may perform beamforming. For beamforming, the RF processing unit (10) may adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. Additionally, the RF processing unit may perform MIMO and may receive multiple layers when performing MIMO operation.

[0114] The baseband processing unit (20) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence. In addition, when receiving data, the baseband processing unit (20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (10). For example, in the case of following the orthogonal frequency division multiplexing (OFDM) method, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through inverse fast Fourier transform (IFFT) operations and cyclic prefix (CP) insertion. Additionally, upon receiving data, the baseband processing unit (20) divides the baseband signal provided by the RF processing unit (10) into OFDM symbol units, restores the signals mapped to subcarriers through a fast Fourier transform (FFT), and then restores the received bit sequence through demodulation and decoding.

[0115] The baseband processing unit (20) and the RF processing unit (10) transmit and receive signals as described above. Accordingly, the baseband processing unit (20) and the RF processing unit (10) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, or a communication unit. Furthermore, at least one of the baseband processing unit (20) and the RF processing unit (10) may include a plurality of communication modules to support a plurality of different wireless access technologies. Additionally, at least one of the baseband processing unit (20) and the RF processing unit (10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. In addition, the above different frequency bands may include super high frequency (SHF) bands (e.g., 2 NRHz, NRHz) and millimeter wave (e.g., 60 GHz) bands.

[0116] The storage unit (30) stores data such as basic programs, application programs, and setting information for the operation of the terminal. The storage unit (30) also provides the stored data in response to a request from the control unit (40).

[0117] The control unit (40) controls the overall operations of the terminal. For example, the control unit (40) transmits and receives signals through the baseband processing unit (20) and the RF processing unit (10). Additionally, the control unit (40) writes and reads data to and from the storage unit (40). To this end, the control unit (40) may include at least one processor. For example, the control unit (40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as applications. Additionally, the control unit (40) may further include a multiple connection processing unit (42) to support multiple connections.

[0118] FIG. 12 is a block diagram of a network entity (1200) performing network functions according to one embodiment of the present disclosure. The network entity (1200) of FIG. 12 may include a network entity of a core network (e.g., an AMF entity) according to the above-described embodiment.

[0119] 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).

[0120] 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.

[0121] 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).

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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).

[0127] 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).

[0128] 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).

[0129] 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.

[0130] 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).

[0131] 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).

[0132] 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.

[0133] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0134] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure.

[0135] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage devices, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0136] Additionally, the above program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0137] In the present disclosure, the terms “computer program product” or “computer readable medium” are used to collectively refer to media such as memory, a hard disk installed in a hard disk drive, and signals. These “computer program product” or “computer readable medium” are configurations provided in a method for reporting terminal capability in a wireless communication system according to the present disclosure.

[0138] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory storage medium' simply means that it is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily. For example, a 'non-transitory storage medium' may include a buffer in which data is stored temporarily.

[0139] According to one embodiment, the method according to the various embodiments disclosed herein may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0140] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation 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 of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0141] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible.

[0142] In addition, each of the above embodiments may be combined and operated as needed. For example, parts of one embodiment of the present disclosure and another embodiment may be combined to operate a base station and a terminal. Furthermore, the embodiments of the present disclosure are applicable to other communication systems, and other variations based on the technical concept of the embodiments may also be implemented. For example, the embodiments may be applied to LTE systems, 5G, NR systems, or 6G systems. 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.

Claims

1. In a method performed by a first base station, A step of determining the RAN (radio access network) paging area for UE (user equipment); A step of deciding to request RAN paging to a second base station not directly connected to the first base station, based on the above RAN paging area; A method comprising the step of transmitting a first message to request paging to the second base station to an AMF (access and mobility management function) entity.

2. In Paragraph 1, The first base station and the second base station are base stations of the RNA (RAN Notification area) set for the UE, or the first base station is a base station of the RNA and the second base station is a base station not included in the RNA, A method in which the first message comprises at least one of information about an identifier of the first base station, information about an identifier of the second base station, or information for a paging request.

3. In Paragraph 1, The above method is, A step of receiving a second message for requesting context information for the UE from the AMF entity; and A method further comprising the step of transmitting a third message containing the context information to the above AMF entity.

4. In Paragraph 3, A method in which the second message further comprises at least one of information regarding an identifier of the second base station or information regarding an identifier of the UE.

5. In a method performed by an AMF (access and mobility management function) entity, A step of receiving a first message from a first base station to request paging to a second base station not directly connected to the first base station, based on a RAN (radio access network) paging area for user equipment (UE); and A method comprising the step of transmitting a second message to the second base station to request paging.

6. In Paragraph 5, The first base station and the second base station are base stations of the RNA (RAN Notification area) set for the UE, or the first base station is a base station of the RNA and the second base station is a base station not included in the RNA, A method in which the first message comprises at least one of information about an identifier of the first base station, information about an identifier of the second base station, or information for a paging request.

7. In Paragraph 5, The above method is, A step of receiving a third message for requesting context information for the UE from the second base station; A step of transmitting a fourth message to the first base station to request the context information for the UE; A step of receiving a fifth message including the context information from the first base station; and A method further comprising the step of transmitting a sixth message containing the context information to the second base station.

8. In Paragraph 7, A method in which the second message further comprises at least one of information regarding an identifier of the second base station or information regarding an identifier of the UE.

9. At the first base station: At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the first base station: Determine the RAN (radio access network) paging area for UE (user equipment), and Based on the above RAN paging area, it is decided to request RAN paging to a second base station that is not directly connected to the first base station, and A first base station that transmits a first message to an AMF (access and mobility management function) entity to request paging to the second base station.

10. In Paragraph 9, The first base station and the second base station are base stations of the RNA (RAN Notification area) set for the UE, or the first base station is a base station of the RNA and the second base station is a base station not included in the RNA, The first message above includes at least one of information about an identifier of the first base station, information about an identifier of the second base station, or information for a paging request, for a first base station.

11. In Paragraph 9, The above commands are: Receive a second message for requesting context information for the UE from the above AMF entity, and A first base station that transmits a third message containing the context information to the above AMF entity.

12. In Paragraph 11, The first base station, wherein the second message further includes at least one of information regarding the identifier of the second base station or information regarding the identifier of the UE.

13. For the AMF (access and mobility management function) entity: At least one processor; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the above AMF entity: Receiving a first message from a first base station to request paging to a second base station not directly connected to the first base station, based on a RAN (radio access network) paging area for a UE (user equipment), and An AMF entity that transmits a second message to the second base station to request the above paging.

14. In Paragraph 13, The first base station and the second base station are base stations of the RNA (RAN Notification area) set for the UE, or the first base station is a base station of the RNA and the second base station is a base station not included in the RNA, The above first message is an AMF entity comprising at least one of information regarding an identifier of the first base station, information regarding an identifier of the second base station, or information for a paging request.

15. In Paragraph 13, The above commands are: Receive a third message for requesting context information for the UE from the second base station, and Transmit a fourth message to request the context information for the UE to the first base station, and Receive a fifth message including the context information from the first base station, and To transmit a sixth message containing the context information to the second base station, and The above second message is an AMF entity that further includes at least one of information regarding an identifier of the second base station or information regarding an identifier of the UE.

Images