Method and device for paging in wireless communication system

Abstract

An operating method of a first base station, according to one embodiment of the present disclosure, comprises the operations of: transmitting confidentiality indication information to user equipment (UE); generating a second identifier on the basis of the confidentiality indication information; and transmitting, to a second base station, a paging message including the second identifier, wherein the confidentiality indication information includes information indicating that a first identifier can be encrypted, and the second identifier can be generated by encrypting the first identifier of the UE, which is in a radio resource control (RRC) inactive state.

Description

Method and device for paging in a wireless communication system

[0001] Embodiments disclosed in this document relate to a paging method and device in a wireless communication system.

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

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

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

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

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

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

[0008] In a wireless communication system, the wireless connection status between a terminal and a base station may include an RRC connected state (RRC connected), indicating a state in which the terminal and the base station are connected, and an RRC idle state (RRC idle), indicating a state in which the terminal and the base station are not connected. Furthermore, 5G NR introduces a new RRC inactive state to reduce terminal power consumption and optimize network resources. A terminal in the RRC inactive state can activate a wireless connection only when necessary, such as when there are downlink packets for the terminal. For this purpose, paging may be performed.

[0009] When a terminal is in an RRC (radio resource control) inactive state, the base station can perform RAN paging for the terminal. The base station can generate a paging message to notify the terminal in the RRC inactive state of the occurrence of an event, such as a call or downlink data transmission. The paging message may include an identifier (e.g., full-RNTI) of the terminal to be paged. In this regard, since there is a concern that the terminal identifier included in the paging message transmitted by the base station to the terminal may be compromised by a third party, confidentiality needs to be provided for the paging message for security purposes.

[0010] Based on the discussion described above, the present disclosure provides a method and device for providing confidentiality when paging a terminal in an RRC (radio resource control) inactive state in a wireless communication system.

[0011] The present disclosure provides a method and apparatus for transmitting information indicating that an identifier to be included in a paging message by a base station in a wireless communication system may be encrypted to a terminal.

[0012] Additionally, the present disclosure provides a method and device for enhancing security in a paging procedure by encrypting a paging identifier in the paging procedure.

[0013] An operating method of a first base station according to one embodiment of the present disclosure includes an operation of transmitting confidentiality indication information to a user equipment (UE), an operation of generating a second identifier based on the confidentiality indication information, and an operation of transmitting a paging message including the second identifier to the second base station, wherein the confidentiality indication information includes information indicating that the first identifier can be encrypted, and the second identifier can be generated by encrypting the first identifier of a UE in an RRC (radio resource control) inactive state.

[0014] A method of operating a UE (user equipment) according to one embodiment of the present disclosure includes an operation of receiving confidentiality indication information from a base station, an operation of receiving a paging message including a second identifier from the base station, and an operation of identifying information indicating that a first identifier included in the confidentiality indication information can be encrypted, wherein the second identifier can be generated by encrypting the first identifier.

[0015] A first base station device according to one embodiment of the present disclosure includes a communication unit, a storage unit, and at least one processor connected to the communication unit and the storage unit, wherein the at least one processor is configured to transmit confidentiality indication information to a user equipment (UE), generate a second identifier based on the confidentiality indication information, and transmit a paging message including the second identifier to a second base station, wherein the confidentiality indication information includes information indicating that the first identifier can be encrypted, and the second identifier can be generated by encrypting the first identifier of a UE in an RRC (radio resource control) inactive state.

[0016] According to one embodiment of the present disclosure, a user equipment (UE) includes a communication unit, a storage unit, and at least one processor connected to the communication unit and the storage unit, wherein the at least one processor is configured to receive confidentiality indication information from a base station, receive a paging message including a second identifier from the base station, and identify information indicating that a first identifier included in the confidentiality indication information can be encrypted, and the second identifier can be generated by encrypting the first identifier.

[0017] Embodiments of the present disclosure provide an effect capable of preventing personal information leakage in a paging procedure of a user equipment (UE) in an RRC (radio resource control) inactive state.

[0018] In addition, in the paging procedure of the UE, it provides the effect of selecting the optimal security algorithm by considering the security capabilities of the UE and the base station.

[0019] Additionally, by encrypting the UE identifier by considering the connection history between the UE and the base station, it provides the effect of strengthening the security of the UE where there is a concern about personal information leakage.

[0020] The effects that can be obtained from the present disclosure are not limited to the effects mentioned in the various embodiments, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0021] FIG. 1 illustrates a wireless communication system according to embodiments of the present disclosure.

[0022] FIG. 2a illustrates a signaling flow between a user equipment (UE), a base station, and a network device according to embodiments of the present disclosure.

[0023] FIG. 2b illustrates signaling flows between a user equipment (UE), a base station, and a network device according to embodiments of the present disclosure.

[0024] FIG. 3A illustrates an example of a functional structure of a terminal according to embodiments of the present disclosure.

[0025] FIG. 3b illustrates an example of a functional structure of a base station according to embodiments of the present disclosure.

[0026] FIG. 3c illustrates an example of the functional structure of objects constituting a core network according to embodiments of the present disclosure.

[0027] Figure 4 illustrates the signaling flow between a base station and a terminal according to one embodiment.

[0028] Figure 5 illustrates a signaling flow between a base station and a terminal according to one embodiment.

[0029] Figure 6 illustrates the signaling flow between a base station and a terminal according to one embodiment.

[0030] Figure 7 illustrates the signaling flow between a base station and a terminal according to one embodiment.

[0031] Figure 8 illustrates the signaling flow between a base station and a terminal according to one embodiment.

[0032] Figure 9 illustrates the signaling flow between a base station and a terminal according to one embodiment.

[0033] Figure 10 illustrates the operation flow of a base station according to one embodiment.

[0034] Figure 11 illustrates the operation flow of a first base station according to one embodiment.

[0035] Figure 12 illustrates the operation flow of a UE according to one embodiment.

[0036] Figure 13 illustrates the operation flow of a first base station according to one embodiment.

[0037] Figure 14 illustrates the operation flow of a second base station according to one embodiment.

[0038] Figure 15 illustrates the operation flow of a UE according to one embodiment.

[0039] Figure 16 illustrates a signaling flow of a terminal, a base station, and a network device according to one embodiment.

[0040] In connection with the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0041] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0042] The various embodiments of the present disclosure described below illustrate a hardware-based approach as an example. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0043] 3GPP, responsible for cellular mobile communications standards, is standardizing a new core network architecture, dubbed 5G core (5GC), to facilitate the evolution of existing 4G LTE systems into 5G systems. Compared to the evolved packet core (EPC), the network core for existing 4G systems, 5GC supports the following differentiated features:

[0044] First, 5GC introduces network slicing. As a 5G requirement, 5GC must support various terminal types and services (e.g., eMBB, URLLC, or mMTC services). Each type of service has different requirements for the core network. For example, eMBB services require high data rates, while URLLC services require high reliability and low latency. One technology proposed to meet these diverse service requirements is network slicing.

[0045] Network slicing virtualizes a single physical network to create multiple logical networks. Each network slice instance (NSI) can have different characteristics. Therefore, each NSI can satisfy diverse service requirements by possessing a network function (NF) tailored to its characteristics. If each terminal is assigned an NSI that matches the characteristics of the service it requires, multiple 5G services can be efficiently supported.

[0046] Second, 5GC can facilitate support for the network virtualization paradigm by separating mobility management and session management functions. In 4G LTE (long term evolution), services were provided through signaling exchanges with a single core device called the mobility management entity (MME), which was responsible for registration, authentication, mobility management, and session management for all terminals. However, in 5G, the number of terminals increases explosively, and the mobility and traffic / session characteristics that must be supported for each terminal type become more specialized. Therefore, supporting all functions with a single device like the MME inevitably reduces scalability by adding entities for each required function. Therefore, various functions are being developed based on a structure that separates mobility management and session management functions to improve scalability in terms of functional / implementation complexity and signaling load of the core device responsible for the control plane.

[0047] Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. Furthermore, when describing embodiments of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the embodiments. Furthermore, the terms described below are defined in consideration of their functions in the embodiments, and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents throughout this specification.

[0048] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0049] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0050] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0051] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0052] Here, the term '~ unit' used in various embodiments of the present disclosure means a software or hardware component such as an FPGA or ASIC, and the '~ unit' can perform certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Accordingly, as an example, the '~ unit' may include components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, components and '~parts' may be implemented to regenerate one or more CPUs within a device or secure multimedia card.

[0053] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of an eNode B (eNB), a Node B, a BS (base station), a RAN (radio access network), an AN (access network), a RAN node, a NR NB, a gNB, a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In various embodiments of the present disclosure, a case where the terminal is a UE will be described as an example. In addition, although various embodiments of the present disclosure are described below using a system based on LTE, LTE-A, or NR as an example, various embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type. In addition, various embodiments of the present disclosure may be applied to other communication systems with some modifications within a range that does not significantly depart from the scope thereof at the discretion of a person having skilled technical knowledge.

[0054] The 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 provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0055] Additionally, while this disclosure describes various embodiments using terminology used in certain communication standards (e.g., 3rd Generation Partnership Project (3GPP)), these are merely illustrative examples. The various embodiments of this disclosure can be easily modified and applied to other communication systems. Below, some terms used in the core network of this disclosure are predefined.

[0056] AMF Access and Mobility Management Function

[0057] CN Core Network

[0058] DN Data Network

[0059] PCF Policy Control Function

[0060] RAN Radio Access Network

[0061] SMF Session Management Function

[0062] UDM User Data Management

[0063] UPF User Plane Function

[0064] FIG. 1 illustrates a wireless communication system according to embodiments of the present disclosure.

[0065] Referring to FIG. 1, in a wireless communication system (100), a wireless paging area (101) (RAN notification area) may include a plurality of base stations (BSs) (e.g., a first base station (121), a second base station (122)). The wireless paging area (101) may be an area set up to provide RAN paging. The plurality of base stations (121, 122) may be connected to each other via a backhaul network. The plurality of base stations (121, 122) may perform wireless communication with a user equipment (UE) (110). In the wireless communication system (100), a network device (130) may be configured to be connected to a plurality of base stations (121, 122) included in the wireless paging area (101). The network device (130) may be, for example, one of the entities constituting a core network.

[0066] The UE (110) can communicate with a core network entity (e.g., a network device (130)) via a BS (e.g., a first base station (121) and a second base station (122)). The UE (110) is a device used by a user and may include a device configured to provide a user interface (UI). For example, the UE (110) may include a terminal mounted (equipment) on a vehicle for driving. In addition, for example, the UE (110) may be a device that performs machine type communication (MTC) that operates without the intervention of a user, or may include an autonomous vehicle. UE may be referred to as a 'terminal', 'vehicle terminal', 'user equipment (UE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal', or 'user device' or other terms having equivalent technical meanings, other than electronic devices. As the terminal, in addition to the UE, a customer-premises equipment (CPE) or a dongle-type terminal may be used. The CPE, like the UE, connects to a next generation (NG)-RAN node, while also providing a network to other communication devices (e.g., a laptop).

[0067] The RAN is a network connected to a user device (e.g., UE (110)) and may include infrastructure for providing wireless access to the user device. The RAN may include a set of a plurality of base stations including a base station (e.g., a first base station (121) and a second base station (122)). The plurality of base stations may communicate through an interface formed between each other (e.g., an Xn-C interface). At least some of the interfaces between the plurality of base stations may be wired or wireless.

[0068] Although not shown in the drawing, the first base station (121) and the second base station (122) may have a structure separated into a central unit (CU) and a distributed unit (DU). One CU may control multiple DUs. The base station may be referred to as an 'access point (AP)', a 'next generation node B (gNB)', a '5th generation node', a 'wireless point', a 'transmission / reception point (TRP)', or other terms having equivalent technical meanings.

[0069] The first base station (121) and the second base station (122) are base stations for 5G NR, and may be base stations such as NG-RAN and gNB. The first base station (121) and the second base station (122) may be the same type of base station (e.g., gNB), but they are designated by different indicators depending on the role they perform (e.g., the first base station (121) is the last serving gNB, and the second base station (122) is the remaining base station in the RNA).

[0070] The first base station (121) may be referred to as the last serving gNB, as it is the last base station to which the UE (110) was RRC-connected before transitioning to the RRC inactive state. The second base stations (122-1, 122-2, 122-3, 122-4) may refer to the remaining base stations excluding the first base station (121) existing within the wireless paging area (101). The second base stations (122-1, 122-2, 122-3, 122-4) may include, for example, adjacent base stations to which the UE (110) may move through a handover procedure from the first base station (121). Although FIG. 1 illustrates that there are five second base stations within the wireless paging area (101), this is merely an example, and fewer or more second base stations than five may exist within the wireless paging area (101).

[0071] The network device (130) may be a network device capable of performing a procedure for paging the UE (110). For example, the network device (130) may be an AMF (access and mobility management function) that provides mobility management functions for the UE among entities included in the core network, or a UPF (user plane function) that performs a data transmission role.

[0072] The UE (110) may be in an RRC inactive state. In 5G NR, a UE that does not transmit or receive data for a certain period of time may transition to an RRC inactive state rather than an RRC idle state. For the UE (110) in the RRC inactive state, a radio paging area (RAN notification area, RNA) (101) may exist. Although not shown in the drawing, for the UE (110) in the RRC inactive state, a core network tracking area (CN TA) may exist in addition to the radio paging area (101).

[0073] The UE (110) may transition to an RRC inactive state while in a connected state (RRC connected) with the first base station (121). After the UE (110) transitions to the RRC inactive state, it may still be within a range that can be connected to the first base station (121), but may move out of the range that can be connected to the first base station (121) and within the range of another base station within the wireless paging area (101), i.e., the second base station (122-1, 122-2, 122-3, 122-4, 122-5). The UE (110) may move within the wireless paging area while in the RRC inactive state without notifying other base stations (e.g., the second base station (122)) other than the first base station (121) that the state has transitioned. In this case, the UE (110) may maintain a CM (connection management)-connected state. The first base station (121) (last serving gNB) can maintain the context of the UE (110) in the RRC inactive state and maintain the NG-connection with the network device (130), such as the serving AMF and serving UPF of the UE (110).

[0074] While the UE (110) maintains the RRC inactive state, the first base station (121) can receive downlink data from the network device (130). When the first base station (121) receives downlink data from the network device (130) while the UE (110) is in the RRC inactive state, the first base station (121) can perform an operation according to a paging procedure, and for this purpose, can transmit RAN paging to the second base station (122).

[0075] Messages for paging between a first base station (121) and at least one second base station (122) (e.g., RAN paging, Inter-gNB paging, etc.) can be transmitted and received via the Xn-C interface. The Xn-C interface may mean an Xn control plane interface between two NG-RANs (e.g., the first base station (121) and the second base station (122)). The Xn-C interface may be an interface that supports UE mobility management, RAN paging, or dual connectivity.

[0076] FIG. 2A or FIG. 2B illustrates a signaling flow in a wireless communication system (e.g., the wireless communication system (100) of FIG. 1) according to one embodiment. FIG. 2A or FIG. 2B relates to a signaling flow for paging a UE in an RRC inactive state according to embodiments of the present disclosure. FIG. 2A relates to a signaling flow when a first base station (121) performs encryption, and FIG. 2B relates to a signaling flow when a second base station (122) performs encryption. In the description of FIG. 2A or FIG. 2B, any content that overlaps with that described in FIG. 1 may be omitted.

[0077] The paging procedure may allow a base station to access a UE in an RRC idle state or an RRC inactive state of a network (e.g., a network device (130)) via a paging message. A UE in an RRC inactive state may monitor a paging channel for RAN-initiated paging or CN-initiated paging. The UE may not continuously monitor the paging channel, but may only monitor the paging channel during one paging occasion (PO) of a paging DRX (discontinuous reception) cycle.

[0078] Referring to FIG. 2A or FIG. 2B, in operation 210, the network device (130) may transmit a paging trigger for the UE (110) to the first base station (121). The paging trigger may be downlink (DL) data for the UE (110). In response to receiving data for the UE (110) from a data network (DN), the network device (130) may transmit the data to the first base station (121), which is the last serving gNB of the UE (110).

[0079] In operation 210, the first base station (121) may receive a paging trigger (downlink data) for the UE (110) from the network device (130). In response to receiving the paging trigger from the network device (130), the first base station (121) may determine whether the UE (110) is in an RRC inactive state. If the first base station (121) identifies that the UE (110) is in an RRC inactive state, the first base station (121) may initiate a RAN paging procedure for the UE (110).

[0080] In response to identifying that the UE (110) is in an RRC inactive state, the first base station (121) may perform operations 221 and 222 as illustrated in FIG. 2a, or may perform operations 223 and 224 as illustrated in FIG. 2b.

[0081] Referring to FIG. 2A, in operation 221, the first base station (121) may encrypt the first identifier of the UE (110) to which the paging trigger received from the network device (130) is to be transmitted, to generate a second identifier. The first identifier may be a type of identifier of the UE (110). For example, the first identifier may be a type of radio network temporary identifier (RNTI) of the UE (110) (e.g., full-RNTI, I-RNTI). Thereafter, in operation 222, the first base station (121) may transmit RAN paging including the generated second identifier to the second base station (122). The second base station (122) may be, for example, a neighboring base station to which the UE (110) may move from the first base station (121), or one of the neighboring base stations.

[0082] Referring to FIG. 2B, in operation 223, the first base station (121) may transmit a first identifier of the UE (110) and security context information for encryption of the first identifier to the second base station (122). The first identifier may be a type of identifier of the UE (110). For example, the first identifier may be a type of RNTI (e.g., full-RNTI, I-RNTI) of the UE (110). The second base station (122) may be, for example, an adjacent base station to which the UE (110) may move from the first base station (121), or one of the adjacent base stations. Thereafter, in operation 224, the second base station (122) may encrypt the first identifier to generate a second identifier in response to receiving the first identifier and security context information for encryption of the first identifier from the first base station (121).

[0083] The first base station (121) can determine whether to perform encryption directly, as illustrated in FIG. 2A, or to provide relevant information so that the second base station (122) can perform encryption, as illustrated in FIG. 2B. Whether the first base station (121) performs encryption directly according to FIG. 2A, or whether the second base station (122) performs encryption according to FIG. 2B, can be determined by the first base station (121) or by information received from the network device (130).

[0084] In one embodiment, although not shown in the drawing, the first base station (121), the second base station (122), and the UE (110) may transmit and receive information for encrypting the first identifier of the UE (110). For example, the transmission or reception of information for encrypting the first identifier of the UE (110) may be performed before the signaling procedure for paging the UE (110) shown in FIGS. 2A and 2B is performed (before the UE (110) transitions to the RRC inactive state). In other words, the UE (110) may perform a negotiation procedure for encrypting the first identifier with neighboring base stations in an RRC connected state before transitioning to the RRC inactive state.

[0085] The first base station (121) or the second base station (122) may transmit confidentiality indication information to the UE (110). For example, the confidentiality indication information may include an indicator indicating that the first base station (121) or the second base station (122) can support encryption of the first identifier. For example, the confidentiality indication information may include an indicator indicating that the first base station (121) or the second base station (122) can encrypt the first identifier to be included in the paging message. For example, the confidentiality indication information may include information regarding a security context (e.g., a type of security algorithm, a type of security key, etc.) used by the first base station (121) or the second base station (122) to encrypt the first identifier of the UE (110). For example, the confidentiality indication information may be information to inform that a base station (e.g., a first base station (121) or a second base station (122)) that is likely to provide a paging message to the UE (110) has the ability to encrypt the first identifier.

[0086] In response to receiving confidentiality indication information transmitted by the first base station (121) or the second base station (122), the UE (110) may transmit a confidentiality response to the first base station (121) or the second base station (122). For example, the confidentiality response may include information indicating that the UE (110) has confirmed the confidentiality indication information of the first base station (121) or the second base station (122). For example, the confidentiality response may include information (e.g., possible / disabled) regarding whether the UE (110) can apply encryption of the first identifier according to the confidentiality indication information of the first base station (121) or the second base station (122) to the paging procedure. When the confidentiality response transmitted by the UE (110) to the first base station (121) or the second base station (122) includes information indicating that the UE (110) cannot apply encryption of the first identifier according to the confidentiality indication information, information regarding the reason for the inapplicability (e.g., unsupported hardware (e.g., modem), unsupported security algorithm, etc.) may be included.

[0087] The UE (110) may transmit a confidentiality application request to the first base station (121) or the second base station (122). The confidentiality application request may be a request for the first base station (121) or the second base station (122) to apply encryption to the first identifier of the UE (110) included in the paging message. When the UE (110) transmits the confidentiality application request to the first base station (121) or the second base station (122), the first base station (121) or the second base station (122) may transmit confidentiality indication information in response thereto. At this time, the confidentiality indication information may include information (e.g., possible / impossible) regarding whether the first base station (121) or the second base station (122) can apply the encryption requested by the UE (110). When the confidentiality indication information transmitted in response to the first base station (121) or the second base station (122) receiving a confidentiality application request from the UE (110) includes information indicating that the first base station (121) or the second base station (122) cannot perform encryption of the first identifier requested by the UE (110), the confidentiality indication information may include information regarding the reason why encryption of the first identifier cannot be performed.

[0088] In one embodiment, although not shown in the drawing, the first base station (121) may perform encryption of the first identifier of the UE (110) based on whether the UE (110) satisfies a confidentiality requirement. In other words, the first base station (121) may receive downlink data according to operation 210, identify that the UE (110) is in an RRC inactive state, and then determine whether the UE (110) satisfies the confidentiality requirement. For example, the confidentiality requirement may include a case where the first base station (121), the second base station (122), or the network device (130) identifies that the UE (110) is in an RRC inactive state for a predetermined period of time or longer. For example, the confidentiality requirement may include a case where the first base station (121) or the second base station (122) identifies that the identifier of the UE (110) used for paging the UE (110) during the paging process (e.g., if encryption has never been performed: a first identifier, if encryption of the first identifier has been performed in a previous paging process: a second identifier generated by encrypting the first identifier) ​​has been used a predetermined number of times or more. For example, the confidentiality requirement may include a case where the first base station (121), the second base station (122), or the network device (130) identifies that the identifier of the UE (110) used for paging the UE (110) remains the same for a predetermined amount of time or more. The first base station (121), the second base station (122), or the network device (130) may determine to encrypt the first identifier of the UE (110) during the paging process if the first base station (121), the second base station (122), or the network device (130) identifies that the UE (110) satisfies the confidentiality requirement.

[0089] The first base station (121) or the second base station (122) may receive information regarding confidentiality requirements from the network device (130). The information regarding confidentiality requirements may include information regarding encryption requirements of the first identifier (e.g., information regarding the elapsed time since the UE transitioned to the RRC inactive state, the number of times, the elapsed time since the UE's identifier (including encrypted and unencrypted) began to be used for paging, etc.). The information regarding confidentiality requirements may include an encryption policy directive that indicates whether the first base station (121) or the second base station (122) performs encryption of the first identifier based on the confidentiality requirements. For example, the encryption policy directive may indicate that the base station must apply the confidentiality requirements according to the network's instructions. For example, the encryption policy directive may indicate that the base station can apply the confidentiality requirements optionally. For example, the encryption policy directive may indicate that the base station will not apply the confidentiality requirements. The first base station (121) or the second base station (122) can determine whether to apply the confidentiality requirement based on the encryption policy indicator included in the information regarding the confidentiality requirement.

[0090] Before the signaling procedure for paging of the UE (110) illustrated in the above-described FIGS. 2A and 2B is performed, signaling regarding encryption of the first identifier performed between the first base station (121), the second base station (122) and the UE (110), and the confidentiality requirements of the first base station (121) or the second base station (122) can be described in detail in the drawings described below.

[0091] According to one embodiment, in operation 230, the first base station (121) or the second base station (122) and the UE (110) may perform a paging procedure. The UE (110) may receive a paging message including an encrypted second identifier from the first base station (121) or the second base station (122). For example, if the UE (110) transitions to an RRC inactive state and is still within the connection range of the first base station (121), the first base station (121) may transmit a paging message including the second identifier to the UE (110). For example, if the UE (110) transitions to an RRC inactive state and is out of the connection range of the first base station (121) and within the connection range of the second base station (122), the second base station (122) may transmit a paging message including the second identifier to the UE (110).

[0092] A paging message may include a paging list (e.g., a paging record list). The paging list may refer to a list of at least one UE that is the target of paging. The paging list may include at least one paging identification (e.g., a paging record). The paging identification may include identification information (e.g., a full-RNTI or an encrypted full-RNTI) of the UE that is the target of paging.

[0093] A paging message may include identification information of the UE and an encryption application indicator indicating whether the identification information is encrypted. The encryption application indicator may indicate whether the UE identifier included in the paging message is encrypted or not.

[0094] According to one embodiment, the UE (110) can check whether the paging message received from the base station (e.g., the first base station (121) or the second base station (122)) includes identification information of the UE (110).

[0095] For example, the UE (110) can identify that encryption can be performed on the first identifier of the UE (110) included in the paging message received from the first base station (121) or the second base station (122) through confidentiality indication information received from the base station. In this case, the UE (110) can determine whether the second identifier of the UE (110) is included in at least one piece of identification information of the UE included in the paging message received from the first base station (121) or the second base station (122).

[0096] For example, if the UE (110) identifies that encryption can be performed on the identifier of the UE (110) through an encryption application indicator included in the paging message (e.g., if the UE (110) satisfies the confidentiality requirement and encryption is performed), the UE (110) can determine whether the second identifier of the UE (110) is included in at least one identification information of the UE included in the paging message received from the base station.

[0097] For example, if the UE (110) does not receive confidentiality indication information from the base station or identifies that the base station cannot perform encryption through the confidentiality indication information, the UE (110) may determine whether the first identifier of the UE (110) is included in at least one UE identification information included in a paging message received from the base station.

[0098] For example, if the UE (110) identifies, through an encryption application indicator included in a paging message, that encryption has not been performed on the identifier of the UE (110) (e.g., encryption is not performed because the UE (110) does not satisfy the confidentiality requirement), the UE (110) can determine whether at least one of the UE's identification information included in the paging message received from the base station includes a first identifier of the UE (110) that is not an encrypted identifier.

[0099] According to one embodiment, in operation 240, the UE (110), the first base station (121), the second base station (122), and the network device (130) may perform operations for the RRC connection of the UE (110). The UE (110) may transmit an RRC resume request to the base station in order to transition from an RRC inactive state to an RRC connected state. If the UE (110) determines that the paging message received from the base station includes identification information of the UE (110), the UE (110) may transmit the RRC resume request to the base station. Accordingly, the base station may perform the RRC connection of the UE (110), and thereafter, the downlink data received in operation 210 may be transmitted to the UE (110).

[0100] In one embodiment, although not shown in the drawing, a second identifier encrypted based on the first identifier may be included in a message used for the paging procedure of operation 230, the RRC connection procedure of operation 240, or signaling regarding an RRC state between the UE (110) and a base station (e.g., the first base station (121), the second base station (122)), and the network (e.g., the network device (130)).

[0101] In one embodiment, the identifier of the UE encrypted by the base station (e.g., operation 221, operation 224) may be included in an RRC reconnection request message (e.g., RRCResumeRequest, RRCResumeRequest1) transmitted by the terminal to the base station. For example, the identifier of the UE (e.g., resumeIdentity) included in the RRC reconnection request message may be an encrypted identifier.

[0102] In one embodiment, the identifier of the UE encrypted by the base station (e.g., operation 221, operation 224) may be included in an RRC release message (e.g., RRCRelease) transmitted by the base station to the terminal. For example, the identifier of the UE in the RRC release message (e.g., full-RNTI included in SuspendConfig of RRCRelease-IEs) may be an encrypted identifier.

[0103] FIG. 3A illustrates an example of the functional structure of a terminal according to embodiments of the present disclosure. The configuration illustrated in FIG. 3A can be understood as the configuration of UE (110). Terms such as "...unit" and "...unit" used hereinafter refer to a unit that processes at least one function or operation, which can be implemented using hardware, software, or a combination of hardware and software.

[0104] Referring to FIG. 3A, a UE (110) according to one embodiment may include a communication unit (305), a storage unit (310), and a control unit (315).

[0105] The communication unit (305) can perform functions for transmitting and receiving signals through a wireless channel. For example, the communication unit (305) can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (305) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the communication unit (305) can restore a reception bit stream by demodulating and decoding a baseband signal. In addition, the communication unit (305) can up-convert a baseband signal to an RF band signal and then transmit it through an antenna, and down-convert an RF band signal received through the antenna to a baseband signal. For example, the communication unit (305) can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0106] The communication unit (305) may include a plurality of transmit and receive paths. The communication unit (205) may include at least one antenna array composed of a plurality of antenna elements. The communication unit (305) may be composed of digital circuits and analog circuits (e.g., a radio frequency integrated circuit (RFIC)). Here, the digital circuits and analog circuits may be implemented in a single package. In addition, the communication unit (305) may include a plurality of RF chains. The communication unit (305) may perform beamforming.

[0107] The communication unit (305) can transmit and receive signals as described above. In the following description, all or part of the communication unit (305) may be referred to as a "transmitter," a "receiver," or a "transmitting and receiving unit." Furthermore, in the following description, transmission and reception performed through a wireless channel may be used to mean that processing as described above is performed by the communication unit (305).

[0108] The storage unit (310) can store data such as basic programs, application programs, and setting information for the operation of the terminal. The storage unit (310) can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the storage unit (310) can provide stored data upon request from the control unit (315).

[0109] The control unit (315) can control the overall operations of the terminal. For example, the control unit (315) can transmit and receive signals through the communication unit (305). In addition, the control unit (315) can record and read data in the storage unit (310). The control unit (315) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (315) may include at least one processor or microprocessor, or may include a portion of a processor. In addition, a portion of the communication unit (305) and the control unit (315) may be referred to as a CP (communication processor). According to various embodiments, the control unit (315) can control to perform synchronization using a wireless communication network. For example, the control unit (315) can control the terminal to perform operations according to various embodiments described below.

[0110] FIG. 3B illustrates an example of the functional structure of a base station according to embodiments of the present disclosure. The configuration illustrated in FIG. 3B can be understood as the configuration of a base station (e.g., a first base station (121), a second base station (122)). Terms such as "... unit" and "... unit" used hereinafter refer to a unit that processes at least one function or operation, which can be implemented by hardware, software, or a combination of hardware and software.

[0111] Referring to FIG. 3b, a base station (121, 122) according to one embodiment includes a wireless communication unit (335), a backhaul communication unit (320), a storage unit (325), and a control unit (330).

[0112] The wireless communication unit (335) can perform functions for transmitting and receiving signals via a wireless channel. For example, the wireless communication unit (335) can perform a conversion function between baseband signals and bit streams according to the physical layer specifications of the system. For example, when transmitting data, the wireless communication unit (335) can generate complex symbols by encoding and modulating the transmitted bit stream. Furthermore, when receiving data, the wireless communication unit (335) can restore the received bit stream by demodulating and decoding the baseband signal.

[0113] The wireless communication unit (335) can upconvert a baseband signal into an RF (radio frequency) band signal and transmit it through an antenna, and can downconvert an RF band signal received through the antenna into a baseband signal. To this end, the wireless communication unit (335) can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In addition, the wireless communication unit (335) can include a plurality of transmission and reception paths. Furthermore, the wireless communication unit (335) can include at least one antenna array composed of a plurality of antenna elements.

[0114] In terms of hardware, the wireless communication unit (335) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units depending on operating power, operating frequency, etc. The digital unit may be implemented with at least one processor (e.g., a digital signal processor (DSP)).

[0115] The wireless communication unit (335) can transmit and receive signals as described above. Accordingly, all or part of the wireless communication unit (335) may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, in the following description, transmission and reception performed via a wireless channel may be used to mean that the wireless communication unit (335) performs the processing described above.

[0116] The backhaul communication unit (320) may provide an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (320) may convert a bit string transmitted from a base station to another node, such as another access node, another base station, an upper node, a core network, etc., into a physical signal, and may convert a physical signal received from another node into a bit string.

[0117] The storage unit (325) can store data such as basic programs, application programs, and setting information for the operation of the base station. The storage unit (325) can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the storage unit (325) can provide stored data upon request from the control unit (330).

[0118] The control unit (330) can control the overall operations of the base station. For example, the control unit (330) can transmit and receive signals through the wireless communication unit (335) or the backhaul communication unit (320). In addition, the control unit (330) can record and read data in the storage unit (325). In addition, the control unit (330) can perform functions of a protocol stack required by a communication standard. According to another implementation example, the protocol stack can be included in the wireless communication unit (335). For this purpose, the control unit (330) can include at least one processor. According to various embodiments, the control unit (230) can control to perform synchronization using a wireless communication network. For example, the control unit (330) can control the base station to perform operations according to various embodiments described below.

[0119] FIG. 3C illustrates an example of the functional structure of objects constituting a core network according to embodiments of the present disclosure. The configuration illustrated in FIG. 3C can be understood as a configuration of a device having the function of at least one of the network entities including the network device (130) of FIG. 1. Terms such as "... unit" and "... device" used hereinafter refer to a unit that processes at least one function or operation, and can be implemented by hardware, software, or a combination of hardware and software.

[0120] Referring to FIG. 3c, the core network object is configured to include a communication unit (340), a storage unit (345), and a control unit (350).

[0121] The communication unit (340) may provide an interface for performing communication with other devices within the network. The communication unit (340) may convert a bit string transmitted from a core network entity to another device into a physical signal, and may convert a physical signal received from another device into a bit string. The communication unit (340) may transmit and receive signals. The communication unit (340) may be referred to as a modem, a transmitter, a receiver, or a transceiver. The communication unit (340) may perform a function for enabling the core network entity to communicate with other devices or systems via a backhaul connection (e.g., a wired backhaul or a wireless backhaul) or via a network.

[0122] The storage unit (345) can store data such as basic programs, application programs, and configuration information for the operation of core network objects. The storage unit (345) can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the storage unit (345) can provide stored data upon request from the control unit (350).

[0123] The control unit (350) can control the overall operations of the core network object. For example, the control unit (350) can transmit and receive signals through the communication unit (340). In addition, the control unit (350) can record and read data in the storage unit (345). The control unit (350) can include at least one processor. According to embodiments of the present disclosure, the control unit (350) can perform synchronization using a wireless communication network. For example, the control unit (350) can control the core network object to perform operations according to various embodiments described below.

[0124] The 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, and terms referring to various identification information are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0125] For convenience of explanation, this disclosure may use terms and names defined in the 5GS (5G system) and NR (new radio) standards, the most recent standards defined by the 3GPP organization among the existing communication standards. However, this disclosure is not limited to the above terms and names and may be equally applied to wireless communication networks conforming to other standards. In particular, this disclosure may be applied to the 3GPP 5th generation mobile communication standards (e.g., 5GS and NR).

[0126] FIG. 4 illustrates a signaling flow between a base station and a terminal according to one embodiment. In FIG. 4, the terminal may be a user equipment corresponding to the UE (110) of FIGS. 1 to 2 and 3A. In FIG. 4, the base station may be a base station corresponding to the first base station (121) or the second base station (122) of FIGS. 1 to 2 and 3B. FIG. 4 relates to a negotiation procedure performed in advance between a base station existing in an RNA and a terminal in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between a terminal and a base station according to FIG. 4 may be an operation performed in advance before operation 210 of FIG. 2A is performed.

[0127] Referring to FIG. 4, in operation 410, the base station may transmit confidentiality indication information to the terminal. The confidentiality indication information may include information indicating that the base station has the ability to encrypt a paging identifier (e.g., the UE's full-RNTI).

[0128] The base station can transmit confidentiality indication information to the terminal via unicast. For example, the base station can transmit confidentiality indication information to the terminal using an RRC control message. For example, the base station can transmit confidentiality indication information to the terminal via a signal radio bearer (SRB). This is merely an example, and the base station can also transmit confidentiality indication information to the terminal using RRC signaling.

[0129] The base station can transmit confidential information to the terminal via broadcast. The base station can transmit confidential information to the terminal via system information. For example, the base station can transmit confidentiality indication information to the terminal via the master information block (MIB). For example, the base station can transmit confidentiality indication information to the terminal via the system information block (SIB). The above-described MIB and SIB are examples, and confidentiality indication information may also be included in other signals broadcast by the base station to the terminal.

[0130] The confidentiality indication information may include information regarding the encryption capabilities of the base station. For example, the confidentiality indication information may include information regarding at least one security algorithm that the base station may use to encrypt the identifier of the terminal. For example, the confidentiality indication information may include information regarding a security key or a key derivation function (KDF) that the base station may use to encrypt the identifier of the terminal. For example, the confidentiality indication information may include information necessary for the terminal to decrypt the identifier (i.e., the second identifier) ​​encrypted by the base station. For example, the confidentiality indication information may include information regarding the type of identifier of the terminal that the base station will encrypt (e.g., RNTI, IMSI, SUPI, SUCI, etc.).

[0131] When receiving confidentiality indication information from a base station, the terminal can identify that the paging message to be transmitted by the base station may include an encrypted identifier. In other words, the terminal can identify that a second identifier generated by encrypting the first identifier may be included in the paging message to be received from the base station.

[0132] When receiving confidentiality indication information from a base station, the terminal can determine whether the terminal identifier is present in the paging message based on the encryption information included in the confidentiality indication information. For example, the terminal can determine whether a second identifier, which is an encrypted version of the first identifier, is present in the paging message based on the encryption information included in the confidentiality indication information. For example, the terminal can decrypt at least one identification information included in the paging message based on the encryption information included in the confidentiality indication information, and determine whether the first identifier is present in at least one identifier generated as a result of the decryption.

[0133] The base station can transmit confidentiality indication information in a unicast manner. The base station can transmit confidentiality indication information in a broadcast manner. The base station can transmit confidentiality indication information in both a unicast manner and a broadcast manner. For example, the base station can transmit confidentiality indication information through system information (e.g., a system information block (SIB)).

[0134] FIG. 5 illustrates a signaling flow between a base station and a terminal according to one embodiment. The terminal of FIG. 5 may be a device corresponding to the UE (110) of FIGS. 1 to 2 and 3A and the terminal of FIG. 4. The base station of FIG. 5 may be a device corresponding to the first base station (121) or the second base station (122) of FIGS. 1 to 2 and 3B and the base station of FIG. 4. FIG. 5 relates to a negotiation procedure performed in advance between a base station existing in an RNA and a terminal in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between a terminal and a base station according to FIG. 5 may be an operation performed in advance before operation 210 of FIG. 2A is performed.

[0135] Referring to FIG. 5, at operation 510, the base station may transmit confidentiality indication information. The confidentiality indication information may include information indicating that the base station has the capability to encrypt an identifier (e.g., a full-RNTI of a UE) to be included in a paging message.

[0136] For example, the confidentiality indication information may include information regarding the encryption capabilities of the base station. For example, the confidentiality indication information may include information regarding at least one security algorithm that the base station may use to encrypt the identifier of the terminal. For example, the confidentiality indication information may include information regarding a security key and / or a security key derivation function that the base station may use to encrypt the identifier of the terminal. For example, the confidentiality indication information may include information necessary for the terminal to decrypt an identifier (i.e., a second identifier) ​​encrypted by the base station. For example, the confidentiality indication information may include information regarding the type of identifier of the terminal to be encrypted by the base station (e.g., RNTI, IMSI, SUPI, SUCI, etc.).

[0137] The terminal can receive confidentiality indication information transmitted by the base station. Based on the confidentiality indication information received from the base station, the terminal can determine whether the base station is capable of encrypting an identifier to be included in a paging message. In other words, the terminal can determine that a paging message including a second identifier generated by encrypting a first identifier can be received from the base station.

[0138] For example, a terminal may obtain encrypted information included in confidentiality indication information received from a base station, and based on the encrypted information, encrypt its first identifier to obtain a second identifier. In this case, the terminal may use the second identifier to identify whether a received paging message includes the second identifier.

[0139] In one example, a terminal may obtain encrypted information included in confidentiality indication information received from a base station and use the encrypted information to decrypt an encrypted identifier included in a received paging message. The terminal may determine whether its own identifier, a first identifier, is obtained as a result of the decryption.

[0140] The base station can transmit confidentiality indication information to the terminal via unicast. For example, the base station can transmit confidentiality indication information to the terminal using an RRC control message. For example, the base station can transmit confidentiality indication information to the terminal via a signal radio bearer (SRB). This is merely an example, and the base station can also transmit confidentiality indication information to the terminal using RRC signaling.

[0141] The base station can transmit confidential information to the terminal via broadcast. The base station can transmit confidential information to the terminal via system information. For example, the base station can transmit confidentiality indication information to the terminal via the master information block (MIB). For example, the base station can transmit confidentiality indication information to the terminal via the system information block (SIB). The above-described MIB and SIB are examples, and confidentiality indication information may also be included in other signals broadcast by the base station to the terminal.

[0142] In addition to the examples described above, the base station can transmit confidentiality instruction information through various procedures, and the terminal can also receive confidential instruction information through various procedures.

[0143] According to one embodiment, in operation 520, the terminal may transmit a confidentiality response in response to the confidentiality indication information. The base station may receive the confidentiality response transmitted by the terminal. The confidentiality response may include information indicating that the terminal has confirmed that the base station has the ability to encrypt the paging identifier.

[0144] The confidentiality response may include information indicating whether the terminal can verify the encrypted identifier included in the paging message. For example, the confidentiality response may include information indicating that the terminal has the ability to generate a second identifier by encrypting the first identifier using confidentiality indication information (e.g., a specific security algorithm) received from the base station. For example, the confidentiality response may include information indicating that the terminal does not have the ability to generate a second identifier by encrypting the first identifier using confidentiality indication information (e.g., a specific security algorithm) received from the base station. In this case, the confidentiality response may include information regarding the reason why the second identifier cannot be identified (e.g., if the base station does not support the security algorithm used: information regarding the security algorithm supported by the terminal, if the terminal's modem does not support it).

[0145] FIG. 6 illustrates a signaling flow between a base station and a terminal according to one embodiment. The terminal of FIG. 6 may be a device corresponding to the UE (110) of FIG. 1 to FIG. 2 and FIG. 3A, or the terminal of FIG. 4 and FIG. 5. The base station of FIG. 6 may be a device corresponding to the first base station (121) or the second base station (122) of FIG. 1 to FIG. 2 and FIG. 3B, or the base stations of FIG. 4 and FIG. 5. FIG. 6 relates to a negotiation procedure performed in advance between a base station existing in an RNA and a terminal in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between a terminal and a base station according to FIG. 6 may be an operation performed in advance before operation 210 of FIG. 2A is performed. FIG. 6 relates to an example in which, when a base station transmits confidentiality indication information to a terminal according to FIG. 5, and the terminal transmits a confidentiality response to the base station accordingly, the terminal transmits at least one algorithm selected to be used for encryption through the confidentiality response.

[0146] Referring to FIG. 6, in operation 610, the base station may transmit confidentiality indication information. The terminal may receive the confidentiality indication information transmitted by the base station. Operation 610 may be substantially the same as or similar to the operation according to operation 510, and thus a detailed description thereof will be omitted.

[0147] The confidentiality indication information may include a list of security algorithms that the base station may use to encrypt identifiers to be included in paging messages.

[0148] According to one embodiment, in operation 620, the terminal may select one security algorithm from a list of security algorithms included in the confidentiality indication information. The terminal may select any one of the security algorithms included in the list of security algorithms among the security algorithms it supports.

[0149] According to one embodiment, in operation 630, the terminal may transmit a confidentiality response corresponding to the confidentiality indication information. The base station may receive the confidentiality response transmitted by the terminal. The operation according to operation 630 may be substantially the same as or similar to operation 520 of FIG. 5, and thus, a detailed description thereof will be omitted.

[0150] As an example, the confidentiality response may include a security algorithm indicator indicating the security algorithm selected by the terminal from the security algorithm list. For example, if the security algorithm list includes Algorithm 1, Algorithm 2, Algorithm 3, and Algorithm 4, and the terminal selects Algorithm 1, the security algorithm indicator may have the value "00" indicating Algorithm 1.

[0151] For example, if the terminal does not include a security algorithm that it can support in the security algorithm list, it can transmit information to the base station through a confidentiality response indicating that there is no algorithm that it can support.

[0152] FIG. 7 illustrates a signaling flow between a base station and a terminal according to one embodiment. The terminal of FIG. 7 may be a device corresponding to the UE (110) of FIG. 1 to FIG. 2 and FIG. 3A, or the terminal of FIG. 4 to FIG. 6. The base station of FIG. 7 may be a device corresponding to the first base station (121) or the second base station (122) of FIG. 1 to FIG. 2 and FIG. 3B, or the base stations of FIG. 4 to FIG. 6. FIG. 7 relates to a negotiation procedure performed in advance between a base station existing in an RNA and a terminal in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between a terminal and a base station according to FIG. 8 may be an operation performed in advance before operation 210 of FIG. 2A is performed. FIG. 7 relates to an example in which a terminal first transmits a confidentiality application request to the base station before the base station transmits confidentiality indication information to the terminal as illustrated in FIGS. 4 to 6.

[0153] Referring to FIG. 7, in operation 710, a terminal may transmit a confidentiality application request. The base station may receive the confidentiality application request transmitted by the terminal. The confidentiality application request may be transmitted to the base station to request that the terminal encrypt and send an identifier to be included in a paging message for itself.

[0154] The confidentiality request may include information regarding the encryption capabilities of the terminal. For example, the confidentiality request may include information regarding at least one security algorithm that the terminal can use to encrypt the first identifier. For example, the confidentiality request may include information regarding at least one security algorithm that the terminal can use to decrypt the second identifier. For example, the confidentiality request may include information regarding a security key or a security key derivation function that the terminal can use to encrypt the identifier of the terminal. For example, the confidentiality request may include information regarding a security key or a security key derivation function that the terminal can use to decrypt the encrypted identifier of the terminal. For example, the confidentiality request may include information regarding the types of identifiers that the terminal can use (e.g., RNTI, IMSI, SUPI, SUCI, etc.).

[0155] A terminal can send a confidentiality request to a base station based on various procedures. For example, the terminal can send a confidentiality request via RRC signaling with the base station.

[0156] According to one embodiment, in operation 720, the base station may transmit confidentiality indication information in response to a confidentiality application request. The terminal may receive the confidentiality indication information transmitted by the base station. The confidentiality indication information may include information regarding whether the base station has the capability (possible or incapable) to encrypt an identifier to be included in a paging message, based on the confidentiality application request received from the terminal. For example, the confidentiality indication information may include information indicating that the base station has the capability to encrypt an identifier, based on the confidentiality application request (e.g., a specific security algorithm) received from the terminal. For example, the confidentiality indication information may include information indicating that the base station does not have the capability to encrypt an identifier, based on the confidentiality application request (e.g., a specific security algorithm) received from the terminal. In this case, the confidentiality indication information may include information regarding the reason why the base station cannot encrypt the identifier (e.g., when the base station does not support the security algorithm included in the confidentiality application request).

[0157] FIG. 8 illustrates a signaling flow between a base station and a terminal according to one embodiment. The terminal of FIG. 8 may be a device corresponding to the UE (110) of FIG. 1 to FIG. 2 and FIG. 3A, or the terminal of FIG. 4 to FIG. 7. The base station of FIG. 8 may be a device corresponding to the first base station (121) or the second base station (122) of FIG. 1 to FIG. 2 and FIG. 3B, or the base stations of FIG. 4 to FIG. 7. FIG. 8 relates to a negotiation procedure performed in advance between a base station existing in an RNA and a terminal in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between a terminal and a base station according to FIG. 8 may be an operation performed in advance before operation 210 of FIG. 2A is performed. FIG. 8 relates to an operation in which, after a terminal transmits a confidentiality application request to a base station as illustrated in FIG. 7, the base station selects at least one security algorithm included in the confidentiality application request and transmits it to the terminal.

[0158] Referring to FIG. 8, in operation 810, a terminal may transmit a confidentiality application request. The base station may receive the confidentiality application request transmitted by the terminal. The confidentiality application request may be transmitted to the base station to request that the terminal encrypt and send an identifier to be included in a paging message for itself. The operation details of operation 810 may be substantially the same as or similar to operation 710, and thus, a detailed description thereof may be omitted.

[0159] According to one embodiment, in operation 820, the base station may select one of at least one security algorithm identified through the confidentiality application request. The at least one security algorithm may be a security algorithm that the terminal can use to encrypt an identifier. The at least one security algorithm may be a security algorithm that the terminal can use to decrypt an encrypted identifier. For example, the base station may select an algorithm that it can support from among at least one security algorithm that the terminal can support to encrypt or decrypt an identifier.

[0160] According to one embodiment, in operation 830, the base station may transmit confidentiality indication information in response to a confidentiality application request. The terminal may receive the confidentiality indication information transmitted by the base station. The confidentiality indication information may include information regarding the security algorithm selected by the base station. The information regarding the security algorithm may be included in the confidentiality indication information in the form of an indicator indicating the security algorithm selected by the base station.

[0161] The operation of transmitting confidentiality instruction information of the base station according to operation 820 may be substantially the same as or similar to the operation 720 of FIG. 7, and thus a detailed description thereof is omitted.

[0162] Information regarding the algorithm selected by the base station in operation 820 may be transmitted not only through the confidentiality indication information, but also through a separate message. For example, it may be included in a paging message transmitted to the terminal during the paging procedure.

[0163] FIG. 9 illustrates a signaling flow between a base station and a terminal according to one embodiment. The terminal of FIG. 9 may be a device corresponding to the UE (110) of FIGS. 1 to 2 and 3A, or the terminals of FIGS. 4 to 8. The base station of FIG. 9 may be a device corresponding to the first base station (121) or the second base station (122) of FIGS. 1 to 2 and 3B, or the base stations of FIGS. 4 to 8. FIG. 9 relates to an operation in which a base station existing in an RNA receives information regarding encryption of a terminal identifier from a network in advance in order to perform an operation for encrypting a UE identifier in a paging procedure of the UE (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B). For example, the signaling flow between the base station and the terminal according to FIG. 9 may be an operation performed in advance before operation 210 of FIG. 2A is performed. Alternatively, the base station may include part of the operation of receiving a paging trigger from a network device (130) according to operation 210.

[0164] Referring to FIG. 9, at step 910, a network device may transmit information regarding a confidentiality policy to a base station. The base station may receive the information regarding the confidentiality policy transmitted by the network device. The information regarding the confidentiality policy may refer to information for the base station to generate a paging message for a terminal, i.e., information for encrypting the terminal identifier included in the paging message.

[0165] Information about a confidentiality policy may include information about at least one confidentiality requirement, a confidentiality enforcement indicator, and information about a security context. The confidentiality enforcement indicator may include information indicating whether the base station should consider information about the confidentiality policy when encrypting an identifier to be included in a paging message (e.g., Required, Preferred, Not needed). Information about at least one confidentiality requirement may indicate conditions for the base station to encrypt the terminal identifier to be included in the paging message. Information about a security context may include information about a security algorithm, a security key, or the type of identifier to be encrypted, which is required for the base station to perform encryption of the terminal identifier.

[0166] If the confidentiality enforcement directive indicates that confidentiality policy information must be considered, the base station may encrypt the terminal identifier included in the paging message based on the confidentiality policy information. For example, the base station may encrypt the terminal identifier based on information about the security context received from the network device, regardless of whether the terminal satisfies the confidentiality requirements.

[0167] If the confidentiality enforcement indicator indicates that confidentiality policy information is to be selectively considered, the base station may encrypt the terminal identifier to be included in the paging message based on whether the terminal satisfies the default conditions set for the base station or the confidentiality requirements received from the network. In other words, if the confidentiality policy information is identified as optional, the base station may encrypt only the terminal identifier to be included in the paging message for terminals that satisfy at least one confidentiality requirement received from the network.

[0168] At least one confidentiality requirement may include a case where the base station identifies that the terminal's RRC inactivity state has been maintained for a predetermined period of time. If the RRC inactivity state is maintained for a predetermined period of time, it may be desirable to encrypt the identifier to enhance security. Accordingly, if the base station identifies that the terminal's RRC inactivity state has been maintained for a predetermined period of time, it may decide to encrypt the terminal's identifier to be included in the paging message.

[0169] At least one confidentiality requirement may include a case where the base station identifies that the terminal's paging identifier has been used a predetermined number of times. If the terminal identifier included in the paging message (both encrypted and unencrypted) is used a predetermined number of times, the terminal is more likely to be attacked by an attacker, which may pose a security risk. In this case, if the base station identifies that the terminal identifier included in the paging message has been used a predetermined number of times, the base station may encrypt the terminal identifier and include it in the paging message.

[0170] At least one confidentiality requirement may include a case where the base station determines that the identifier of the terminal included in the paging message (including the first identifier and the second identifier) ​​remains the same for a predetermined period of time. If the identifier of the terminal included in the paging message is used for a predetermined period of time without being updated, the probability of the identifier of the terminal being identified by an attacker may increase, which may pose a security risk. In this case, if the identifier of the terminal included in the paging message is used for a predetermined period of time without being updated, the base station may encrypt the identifier of the terminal and include it in the paging message.

[0171] A network device can provide the same confidentiality policy information to base stations (e.g., the first base station (121) and the second base station (122)) existing in the RNA. In other words, the network device can set and transmit confidentiality policy information for each base station. The base station can receive confidentiality policy information set for itself by the network device. In this case, the base station can include an encrypted identifier according to the confidentiality policy information in a paging message for one or more terminals within its connection range that require identifier encryption.

[0172] A network device can transmit confidentiality policy information for each terminal connected to it. In other words, the network device can set confidentiality policy information on a per-terminal basis. The network device can transmit the confidentiality policy information set for each terminal to the corresponding base station. In this case, the base station can encrypt or not the identifier included in the paging message based on whether the terminal being paged has been instructed by the network device to apply confidentiality policy information.

[0173] Fig. 10 illustrates the operational flow of a base station according to one embodiment. Fig. 10 may be a base station corresponding to the first base station (121) or the second base station (122) of Fig. 1. The network device of Fig. 10 may be a device corresponding to the network device (130) of Fig. 1.

[0174] According to one embodiment, in operation 1010, the base station may receive information regarding a confidentiality policy from a network device.

[0175] Information about the confidentiality policy may include information about the encryption policy of a paging message transmitted to a terminal, a confidentiality application indicator indicating whether confidentiality policy application is enforced, information about confidentiality requirements for determining whether to perform encryption of the terminal identifier, and information about a security context for performing encryption of the terminal identifier.

[0176] The confidentiality application indicator can indicate either “Required,” which indicates that the confidentiality policy must be applied, “Preferred,” which indicates that the confidentiality policy can be optionally applied, or “Not needed,” which indicates that the confidentiality policy will not be applied. If the confidentiality application indicator indicates Required, the base station can encrypt the terminal identifier included in the paging message for the terminal. If the confidentiality application indicator indicates Preferred, the base station can selectively encrypt the terminal identifier included in the paging message. At this time, the base station can determine whether the terminal satisfies the confidentiality requirement to determine whether to encrypt the terminal identifier, and can perform encryption only for terminals that satisfy the confidentiality requirement. If the confidentiality application indicator indicates Not needed, the base station may not encrypt the terminal identifier included in the paging message for the terminal.

[0177] Confidentiality enforcement indicators can be determined at the base station level or at the terminal level. For example, a network device can transmit different confidentiality enforcement indicators to the base station for each terminal. For example, if confidentiality enforcement indicators exist at the base station level, the base station can apply confidentiality policy information uniformly to all terminals within its connection range.

[0178] Information regarding confidentiality requirements may include information regarding at least one confidentiality requirement for determining whether the base station performs encryption on the terminal. For example, at least one confidentiality requirement may include a case where the base station identifies that the RRC inactivity state of the terminal has been maintained for a predetermined period of time or longer. For example, at least one confidentiality requirement may include a case where the base station identifies that the number of times the identifier for paging the terminal has been used is a predetermined number of times or longer. For example, at least one confidentiality requirement may include a case where the base station identifies that the identifier of the terminal included in the paging message (including the first identifier and the second identifier) ​​has remained the same for a predetermined period of time or longer.

[0179] Information about the security context may include information about the security context used by the base station to encrypt the terminal identifier included in the paging message. Information about the security context may include information about the security algorithm to be used for encryption, information about the type of terminal identifier to be encrypted, information about the security key to be used for encryption, and the like.

[0180] According to one embodiment, in operation 1020, the base station may determine whether to perform encryption of the identifier of the terminal. Operation 1020 may be an operation performed after receiving a paging trigger according to operation 210 of FIGS. 2A and 2B and determining paging of the terminal, and before performing an operation for encrypting a paging message (e.g., operations 221 and 222 of FIG. 2A or operations 223 and 224 of FIG. 2B).

[0181] If the confidentiality application indicator indicates “Required,” the base station may perform encryption on the terminal identifier included in the paging message for the terminal, regardless of whether the terminal satisfies the confidentiality requirements. If the confidentiality application indicator indicates “Preferred,” the base station may determine whether the terminal satisfies at least one confidentiality requirement. If the base station determines that the terminal satisfies at least one confidentiality requirement, the base station may perform encryption on the terminal identifier included in the paging message for the terminal. If the base station determines that the terminal does not satisfy at least one confidentiality requirement, the base station may not perform encryption on the terminal identifier included in the paging message for the terminal. If the confidentiality application indicator indicates “Not needed,” the base station may not encrypt the terminal identifier included in the paging message for the terminal.

[0182] According to one embodiment, if it is determined to perform encryption on the identifier of the terminal in operation 1020, the base station may encrypt the identifier of the terminal included in the paging message for the terminal in operation 1030. If it is determined not to perform encryption on the identifier of the terminal in operation 1020, the base station may not perform encryption on the identifier of the terminal included in the paging message for the terminal in operation 1040.

[0183] In one embodiment, although not shown in the drawing, the encrypted terminal identifier in operation 1030 may be included in an RRC reconnection request message (e.g., RRCResumeRequest, RRCResumeRequest1) transmitted by the terminal to the base station. For example, the UE identifier (e.g., resumeIdentity) included in the RRC reconnection request message may be an encrypted identifier.

[0184] In one embodiment, although not shown in the drawing, the encrypted terminal identifier in operation 1030 may be included in an RRC release message (e.g., RRCRelease) transmitted by the base station to the terminal. For example, the UE identifier in the RRC release message (e.g., full-RNTI included in SuspendConfig of RRCRelease-IEs) may be an encrypted identifier.

[0185] FIG. 11 illustrates the operational flow of a first base station according to one embodiment. The first base station of FIG. 11 may be a base station corresponding to the first base station (121) of FIG. 1. The UE of FIG. 11 may be a device corresponding to the UE (110) of FIG. 1. The second base station of FIG. 11 may be a base station corresponding to the second base station (122) of FIG. 1. In the description of FIG. 11, parts described in the description of the above-described drawings may be omitted.

[0186] In one embodiment, at operation 1110, the first base station may transmit confidentiality indication information to the UE.

[0187] The confidentiality indication information may include information indicating that the UE's identifier (e.g., full-RNTI) included in a message for paging the UE may be encrypted.

[0188] The first base station can transmit confidentiality indication information using either a unicast or broadcast method. The confidentiality indication information transmitted by the base station can be received by the terminal.

[0189] The confidentiality instruction information may be information corresponding to the confidentiality instruction information described in the descriptions of FIGS. 4 to 10 described above.

[0190] The first base station may receive a confidentiality response indicating that the UE can identify the encrypted first identifier of the UE based on the confidentiality indication information transmitted in operation 1110. The confidentiality response may correspond to the confidentiality response described in the descriptions regarding FIGS. 5 to 10.

[0191] The first base station may receive a confidentiality request from the UE. The confidentiality request may be a request from the UE to the base station to encrypt the UE's identifier for a paging message. The confidentiality request may correspond to the confidentiality request in operation 710 of FIG. 7 or the confidentiality request in operation 810 of FIG. 8 . For example, the confidentiality request may include information regarding a security key or a security key derivation function that the UE can use to decrypt the encrypted UE identifier.

[0192] In response to receiving a confidentiality application request from a UE, the first base station may transmit confidentiality indication information to the UE. The operation of the first base station transmitting confidentiality indication information to the UE in response to receiving a confidentiality application request from the UE may correspond to operation 720 of FIG. 7.

[0193] According to one embodiment, in operation 1120, the first base station may encrypt the first identifier of the UE in the RRC inactive state to generate a second identifier. Operation 1120 may include all of the operation contents according to operation 221 of FIG. 2A and operation 224 of FIG. 2B.

[0194] The first base station can determine whether the UE is in an RRC inactive state. If the UE is determined to be not in an RRC inactive state, the first base station does not need to perform paging and thus does not need to perform encryption on the first identifier. However, if the UE is determined to be in an RRC inactive state, the first base station can perform encryption on the first identifier to generate a second identifier. The second identifier may refer to an identifier of the UE generated by encrypting the first identifier.

[0195] The first base station may generate a second identifier based on information regarding a confidentiality policy received from a network device. The information regarding the confidentiality policy may correspond to the information regarding the confidentiality policy of operation 910 of FIG. 9.

[0196] Information about a confidentiality policy may include information about at least one confidentiality requirement, a confidentiality enforcement indicator, and information about a security context. The confidentiality enforcement indicator may include information indicating whether the first base station should perform encryption based on information about the confidentiality policy transmitted by the network (e.g., Required, Preferred, Not needed). The at least one confidentiality requirement may refer to a condition for the first base station to encrypt the identifier of the UE included in a paging message for the UE. Information about the security context may include information about a security algorithm, a security key, and the type of the identifier of the UE to be encrypted, which are required for the first base station to perform encryption of the identifier of the UE.

[0197] If the confidentiality enforcement indicator indicates that the first base station must perform encryption based on information regarding the confidentiality policy transmitted by the network, the first base station may encrypt the UE's identifier included in the paging message for the UE and transmit it to the UE. In this case, the first base station may perform encryption of the UE's identifier based on information regarding the security context received from the network device, regardless of whether the UE satisfies the information regarding the confidentiality requirements.

[0198] If the confidentiality enforcement indicator indicates that the first base station can selectively apply information regarding confidentiality policies transmitted by the network, the first base station may perform encryption of paging messages based on whether the first base station satisfies a default condition set for the first base station or a confidentiality requirement received from the network. In other words, if the application of confidentiality policy information is identified as optional, the first base station may perform encryption of paging messages only for UEs that satisfy at least one confidentiality requirement received from the network.

[0199] At least one confidentiality requirement may include a case where the first base station identifies that the UE's RRC inactivity state has been maintained for a predetermined period of time or longer. Since it is desirable to encrypt the identifier for enhanced security when the RRC inactivity state has been maintained for a predetermined period of time or longer, the first base station may decide to encrypt the UE's identifier and include it in the paging message if it identifies that the UE's RRC inactivity state has been maintained for a predetermined period of time or longer.

[0200] At least one confidentiality requirement may include a case where the first base station identifies that the identifier for paging the UE has been used a predetermined number of times or more. Since the identifier of the UE included in the paging message (both encrypted and unencrypted) is more likely to be identified by an attacker if it has been used a predetermined number of times or more, the first base station may encrypt the identifier of the UE if it identifies that the identifier of the UE included in the paging message has been used a predetermined number of times or more.

[0201] At least one confidentiality requirement may include a case where the first base station determines that the identifier of the UE included in the paging message (including the first identifier and the second identifier) ​​remains the same for a predetermined period of time. Since a security concern may arise if the identifier of the UE included in the paging message remains the same without being updated for a predetermined period of time, the first base station may decide to encrypt the identifier of the UE if it determines that the identifier of the UE included in the paging message remains the same without being updated for a predetermined period of time.

[0202] A network device can transmit the same confidentiality policy information to base stations within the RNA. In other words, the network can set and transmit confidentiality policy information on a per-base station basis. In this case, the first base station that receives confidentiality policy information from the network device can perform encryption based on the confidentiality policy information for all UEs within its connection range.

[0203] A network device can transmit different confidentiality policy information for each UE connected to the network device. In other words, the network can set confidentiality policy information for each UE and transmit it to each base station. In this case, the first base station can encrypt the paging message based on whether the UE being paged has been instructed by the network device to apply confidentiality policy information.

[0204] The first base station may encrypt the first identifier of the UE to generate a second identifier if the confidentiality application indicator indicates that confidentiality policy information must be applied.

[0205] The first base station may, in response to identifying that the UE satisfies at least one confidentiality requirement, encrypt the first identifier to generate a second identifier, if the confidentiality application indicator indicates to selectively apply confidentiality policy information.

[0206] The first base station may generate a second identifier by encrypting only a portion of the first identifier. The first base station may generate the second identifier by encrypting only the portion of the first identifier that corresponds to information about the UE. For example, the first base station may generate the second identifier by encrypting only the bits corresponding to the identification information of the UE among the multiple bits constituting the first identifier.

[0207] According to one embodiment, in operation 1130, the first base station may transmit a paging message including a second identifier to the second base station. Operation 1130 may include all of the operations according to operation 222 of FIG. 2A and operation 223 of FIG. 2B.

[0208] In one embodiment, although not shown in the drawing, the encrypted terminal identifier in operation 1030 may be included in an RRC reconnection request message (e.g., RRCResumeRequest, RRCResumeRequest1) transmitted by the terminal to the base station. For example, the UE identifier (e.g., resumeIdentity) included in the RRC reconnection request message may be an encrypted identifier.

[0209] In one embodiment, although not shown in the drawing, the encrypted terminal identifier in operation 1030 may be included in an RRC release message (e.g., RRCRelease) transmitted by the base station to the terminal. For example, the UE identifier in the RRC release message (e.g., full-RNTI included in SuspendConfig of RRCRelease-IEs) may be an encrypted identifier.

[0210] Fig. 12 illustrates the operation flow of a UE according to one embodiment. The UE of Fig. 12 may be a UE corresponding to the UE (110) of Fig. 1. The base station of Fig. 12 may be a base station corresponding to the first base station (121) or the second base station (122) of Fig. 1.

[0211] According to one embodiment, in operation 1210, the UE may receive confidentiality indication information from the base station. The confidentiality indication information of operation 1210 may include all of the encryption indication information of FIGS. 4 to 11 (e.g., confidentiality indication information of operation 410, confidentiality indication information of operation 510, confidentiality indication information of operation 610, confidentiality indication information of operation 720, and confidentiality indication information of operation 830).

[0212] The confidentiality indication information may include information regarding the encryption capabilities of the base station. For example, the confidentiality indication information may include information regarding at least one security algorithm that the base station can use to encrypt the identifier of the UE. For example, the confidentiality indication information may include information regarding a security key or a security key derivation function that the base station can use to encrypt the identifier of the UE. For example, the confidentiality indication information may include information necessary for the UE to decrypt an identifier encrypted by the base station (i.e., the second identifier). For example, the confidentiality indication information may include information regarding the type of identifier of the UE that the base station encrypts (e.g., RNTI, IMSI, SUPI, SUCI, etc.).

[0213] When the UE receives confidentiality indication information from the base station, the UE can identify that the first identifier of the UE included in the paging message transmitted by the base station for the UE can be encrypted. In other words, the UE can identify that the second identifier generated by encrypting the first identifier of the UE can be included in the paging message to be received from the base station.

[0214] When the UE receives confidentiality indication information from the base station, the UE can determine whether the UE's identifier is present in the paging message based on the encryption information included in the confidentiality indication information. For example, the UE can encrypt a first identifier to generate a second identifier based on the encryption information included in the confidentiality indication information, and then determine whether an identifier corresponding to the second identifier is present in the paging message. For example, the UE can decrypt at least one identification information included in the paging message based on the encryption information included in the confidentiality indication information, and determine whether an identifier corresponding to the first identifier is present among the at least one identifier generated as a result of the decryption.

[0215] According to one embodiment, at operation 1220, the UE may identify that the first identifier of the UE included in the paging message for the UE may be encrypted based on the confidentiality indication information received at operation 1210. Operation 1210 may be performed in response to the UE receiving the confidentiality indication information from the base station, as described with respect to FIGS. 4 to 11 .

[0216] In response to the base station's identification that the UE is capable of encrypting the first identifier, the UE may transmit a confidentiality response to the base station. The confidentiality response may include information indicating that the UE has confirmed, through confidentiality indication information received from the base station, that the base station is capable of performing encryption on the paging identifier.

[0217] The confidentiality response may include information regarding whether the UE can identify whether the UE is being paged when performing encryption on the UE's identifier according to confidentiality indication information transmitted by the base station to the UE. For example, the confidentiality response may include information indicating that the UE is capable of identifying a second identifier generated by performing encryption on the UE's first identifier according to confidentiality indication information (e.g., a specific security algorithm) received from the base station. For example, the confidentiality response may include information indicating that the UE is unable to identify a second identifier generated by performing encryption on the UE's first identifier according to confidentiality indication information (e.g., a specific security algorithm) received from the base station. In this case, the confidentiality response may include information regarding the reason why the second identifier cannot be identified (e.g., when the base station does not support the security algorithm used: information regarding the security algorithm supported by the UE, when the UE's modem does not support it).

[0218] The UE may transmit a confidentiality application request to the base station before receiving confidentiality indication information from the base station. The operation of the UE transmitting the confidentiality application request to the base station may correspond to operation 710 of FIG. 7 and operation 810 of FIG. 8.

[0219] The confidentiality request may include information regarding the encryption capabilities of the UE. For example, the confidentiality request may include information regarding at least one security algorithm that the UE can use to encrypt the first identifier. For example, the confidentiality request may include information regarding a security key or a security key derivation function that the UE can use to encrypt the identifier of the UE. For example, the confidentiality request may include information regarding the type of identifier of the UE that the base station will encrypt (e.g., RNTI, IMSI, SUPI, SUCI, etc.).

[0220] A UE can send a confidentiality request to a base station through various procedures. For example, the UE can send a confidentiality request to the base station via RRC signaling.

[0221] According to one embodiment, the UE may receive a paging message in an RRC inactive state after the base station has identified encryption capabilities according to operation 1220. The paging message may include a second identifier.

[0222] The UE can decrypt at least one identifier included in the paging message. The paging message may include paging identifiers of not only the UE but also other UEs, and the UE can determine whether to transmit an RRC connection resumption request to the base station based on whether the paging message includes the UE's identifier. Since the UE has identified that the UE's first identifier included in the paging message is encrypted, the UE can decrypt at least one identifier included in the paging message based on the confidentiality indication information received in operation 1210, and determine whether any of the decrypted at least one identifier matches the first identifier.

[0223] The UE may encrypt the first identifier to generate a second identifier based on confidentiality indication information. The UE may determine whether the generated second identifier matches any one of at least one identifier included in the paging message. If the paging message includes multiple identifiers, it may be more efficient to determine whether paging is performed by encrypting the identifier of the UE than to decrypt all of the identifiers. Therefore, the UE may encrypt its first identifier to generate a second identifier and determine whether the generated second identifier is included in the paging message. The UE may encrypt the first identifier of the UE if the number of identifiers included in the paging message is greater than or equal to a predetermined number.

[0224] Fig. 13 illustrates the operational flow of a first base station according to one embodiment. In the description of Fig. 13, any portions that overlap with those described in Figs. 2a to 12 may be omitted.

[0225] According to one embodiment, in operation 1310, the first base station may transmit confidentiality indication information to the UE. Operation 1310 may correspond to the confidentiality indication information transmission operation of the base station of FIGS. 4 to 10.

[0226] According to one embodiment, at operation 1320, the first base station may receive downlink data for the UE from a network device. Operation 1320 may correspond to operation 210 of FIGS. 2A and 2B.

[0227] The first base station may determine whether to initiate paging for the UE. In response to receiving downlink data for the UE from a network device, the first base station may determine whether the UE is in an RRC inactive state. If the first base station determines that the UE is in an RRC inactive state, the first base station may determine to initiate paging for the UE and perform operation 1330. If the first base station determines that the UE is not in an RRC inactive state, the first base station may terminate the operation without initiating paging for the UE.

[0228] According to one embodiment, at operation 1330, the first base station may determine whether to encrypt the first identifier of the UE.

[0229] The first base station may receive a confidentiality response from the UE. Although not illustrated in the drawing, the first base station may receive a confidentiality response in response to transmitting confidentiality indication information in operation 1310. If the confidentiality response includes information indicating that the UE can decrypt the first identifier according to the confidentiality indication information transmitted by the first base station to the UE, the first base station may decide to encrypt the first identifier of the UE.

[0230] The first base station may receive a confidentiality request from the UE. Although not illustrated in the drawing, the first base station may receive a confidentiality request from the UE before operation 1310 is performed. The confidentiality request may be a request by the UE to encrypt the UE's identifier included in a paging message for the UE. When the first base station receives a confidentiality request from the UE, the first base station may decide to encrypt the UE's first identifier.

[0231] According to one embodiment, if the first base station determines not to encrypt the first identifier of the UE, the first base station may perform operation 1380. Operation 1380 may include all of the operations of the first base station (121) according to operations 230 and 240 of FIGS. 2A and 2B . In operation 1380, the first base station may generate a paging message and transmit it to the second base station. If the UE is still within the range of the first base station, the first base station may transmit the paging message directly to the UE. The paging message generated by the first base station in operation 1380 or the paging message generated by the second base station at the request of the first base station may include the first identifier, not the second identifier.

[0232] According to one embodiment, if the first base station determines to encrypt the first identifier of the UE, the first base station may perform operation 1340. In operation 1340, the first base station may determine whether the first base station will perform encryption on the first identifier of the UE. For example, if the UE is within the connectivity range of the first base station, the first base station may determine that the first base station will perform encryption on the first identifier of the UE. For example, if the UE is not within the connectivity range of the first base station, the first base station may determine that a second base station within the connectivity range of the UE will perform encryption on the first identifier of the UE.

[0233] According to one embodiment, if the first base station determines not to encrypt the first identifier of the UE, the first base station may perform operation 1370. In operation 1370, the first base station may transmit a RAN paging including the first identifier of the UE and security context information for encrypting the first identifier of the UE to the second base station. Although not shown in the drawing, if the second base station receives the RAN paging according to operation 1370, the second base station may encrypt the first identifier of the UE to generate a second identifier, and transmit a paging message including the generated second identifier to the UE.

[0234] In one embodiment, if the first base station determines to encrypt the first identifier of the UE, the first base station may perform operation 1350. In operation 1350, the first base station may encrypt the first identifier to generate a second identifier. Operation 1350 may include all of the operation contents of operation 221 of FIG. 2A.

[0235] In one embodiment, at operation 1360, the first base station may transmit a RAN paging message including the generated second identifier to the second base station. If the UE identifies that it is within the connection range of the first base station, the first base station may directly transmit a paging message including the second identifier to the UE.

[0236] Fig. 14 illustrates the operational flow of a second base station according to one embodiment. The second base station of Fig. 14 may be a base station corresponding to the second base station (122) of Fig. 1. The UE of Fig. 14 may be a UE corresponding to the UE (110) of Fig. 1.

[0237] According to one embodiment, in operation 1410, the second base station may transmit confidentiality indication information to the UE. Operation 1410 may correspond to the operation of the base station transmitting confidentiality indication information to the terminal in FIGS. 4 to 10 .

[0238] According to one embodiment, in operation 1420, the second base station may receive RAN paging from the first base station. Operation 1420 may correspond to operation 1360, operation 1370, or operation 1380 of FIG. 13 . For example, if it is determined not to perform encryption on the first identifier, the second base station may receive RAN paging including the first identifier (operation 1380). For example, if it is determined to perform encryption on the first identifier and the first base station determines to perform the encryption itself, the second base station may receive RAN paging including the second identifier (operation 1360). For example, if it is determined to perform encryption on the first identifier and the second base station, not the first base station, determines to perform the encryption, the second base station may receive RAN paging including the first identifier and information regarding a security context for encrypting the first identifier (operation 1370).

[0239] According to one embodiment, at operation 1430, the second base station may determine whether to encrypt the identifier of the UE included in the received RAN paging. For example, if the RAN paging received at operation 1420 includes only the first identifier, the second base station may determine not to encrypt the first identifier, which is the identifier of the UE. For example, if the RAN paging received at operation 1420 includes the first identifier and information for encrypting the first identifier, the second base station may determine to encrypt the first identifier. For example, if the RAN paging received at operation 1420 includes a second identifier generated by encrypting the first identifier, the second base station may determine not to encrypt the identifier of the UE.

[0240] In one embodiment, if the second base station determines to encrypt the identifier of the UE, it may perform operation 1440. In operation 1440, the second base station may encrypt the first identifier to generate a second identifier, and transmit a paging message including the second identifier to the UE.

[0241] In one embodiment, if the second base station determines not to encrypt the identifier of the UE, operation 1450 may be performed. In operation 1450, the second base station may transmit a paging message to the UE that includes the identifier of the UE included in the RAN paging.

[0242] Fig. 15 illustrates the operation flow of a UE according to one embodiment. The UE of Fig. 15 may be a UE corresponding to the UE (110) of Fig. 1. The base station of Fig. 15 may be a base station corresponding to the first base station (121) or the second base station (122) of Fig. 1.

[0243] According to one embodiment, in operation 1510, the UE may receive confidentiality indication information from the base station. Operation 1510 may correspond to the operation of the UE receiving confidentiality indication information from the base station in FIGS. 4 to 10.

[0244] According to one embodiment, in operation 1520, the UE may receive a paging message from the base station. Operation 1520 may correspond to the operation 230 of FIGS. 2A and 2B in which the UE receives a paging message from the first base station (121) or the second base station (122).

[0245] According to one embodiment, at operation 1530, the UE may determine whether the identifier of the UE included in the paging message is encrypted.

[0246] The UE may determine whether the UE identifier included in the paging message is encrypted based on the confidentiality indication information received from the base station. For example, if the confidentiality indication information includes information indicating that the UE identifier included in the paging message for the UE is encrypted, the UE may determine that the UE identifier included in the paging message is encrypted. For example, if the UE transmits a confidentiality response to the base station indicating that the UE cannot perform decryption based on the confidentiality indication information, the UE may determine that the UE identifier included in the paging message is not encrypted.

[0247] According to one embodiment, if it is determined that the identifier of the UE included in the paging message is encrypted, in operation 1540, the UE may encrypt the first identifier of the UE or decrypt at least one piece of identification information included in the paging message.

[0248] The UE can decrypt at least one identifier included in the paging message. Since the UE has identified that the identifier in the paging message is encrypted, the UE can decrypt at least one identifier included in the paging message to determine that an identifier other than the first identifier is included and has a different encrypted value.

[0249] The UE can encrypt the UE's first identifier to generate a second identifier. If the number of identifiers included in a paging message exceeds a predetermined number, performing decryption on all identifiers may be inefficient. Therefore, the UE can directly encrypt the first identifier to generate a second identifier and determine whether identification information corresponding to the generated second identifier is included in the paging message.

[0250] According to one embodiment, in operation 1550, the UE may determine whether to perform paging. The UE may determine to perform paging if the at least one piece of identification information decrypted in operation 1540 includes identification information corresponding to the first identifier, or if the paging message includes identification information corresponding to a second identifier generated by encrypting the first identifier.

[0251] According to one embodiment, at operation 1560, the UE may transmit a message for RRC connection to the base station.

[0252] The message for RRC connection may include an encrypted UE identifier, i.e. a second identifier.

[0253] FIG. 16 illustrates a signaling flow of a terminal, a base station, and a network device according to an embodiment. The terminal of FIG. 16 may be a device corresponding to the UE (e.g., UE (110), terminal) described in the drawings described above. The base station of FIG. 16 may be a device corresponding to the base stations (e.g., first base station (121), second base station (122), base station) described in the drawings described above. The network device of FIG. 16 may be a device corresponding to the network device (e.g., network device (130)) described in the drawings described above. The UE illustrated in FIG. 16 may be referred to as a “terminal.”

[0254] According to one embodiment, in operation 1610, the network device may transmit confidentiality policy information to the base station. The base station may receive confidentiality policy information from the network device. Operation 1610 may include all of the operation contents of operation 910 of FIG. 9.

[0255] In one embodiment, the confidentiality policy information may include information regarding a policy for the base station to encrypt the identifier of the terminal during the terminal paging procedure. The confidentiality policy information may include a confidentiality application indicator indicating whether confidentiality is to be applied to the identifier of the terminal, information regarding at least one confidentiality requirement indicating a requirement for applying confidentiality to the identifier of the terminal, security context information including information regarding a security algorithm used to encrypt the identifier of the terminal, the type of identifier, etc.

[0256] The confidentiality policy information may include information regarding at least one confidentiality requirement, a confidentiality application indicator indicating whether the at least one confidentiality requirement is applied, and information regarding a security context associated with encryption of the terminal identifier. The information regarding at least one confidentiality requirement may include information regarding conditions for the base station to encrypt the terminal identifier to be included in a paging message. The information regarding the security context may include information regarding a security algorithm, a security key, or the type of identifier to be encrypted, which is required for the base station to perform encryption of the terminal identifier.

[0257] The confidentiality indicator may include information indicating whether the base station will encrypt the identifier included in the paging message. The confidentiality indicator may indicate one of the following: that the base station must encrypt the terminal identifier, that the base station will not apply confidentiality to the terminal identifier, or that the base station will optionally encrypt the terminal identifier.

[0258] At least one confidentiality requirement may include a case where the RRC inactivity state of the terminal is maintained for a predetermined period of time or longer. At least one confidentiality requirement may include a case where the base station identifies that the identifier for paging the terminal has been used a predetermined number of times or longer. At least one confidentiality requirement may include a case where the base station identifies that the identifier of the terminal included in the paging message (including the first identifier and the second identifier) ​​remains the same for a predetermined period of time or longer.

[0259] According to one embodiment, in operation 1620, the terminal may transmit a confidentiality application request to the base station. Operation 1620 may include all of the operations of operation 710 of FIG. 7 and operation 810 of FIG. 8. Operation 1620 may be an operation selectively performed based on the terminal's selection or on pre-determined conditions between the base station and the terminal.

[0260] A confidentiality request may include information requesting encryption of the terminal's identifier, and information regarding the terminal's security capabilities for encrypting the terminal's identifier (e.g., at least one available security algorithm).

[0261] When a base station receives a confidentiality request from a terminal, the base station may determine whether it is capable of performing encryption on the terminal's identifier based on information regarding the terminal's security capabilities included in the confidentiality request. For example, if at least one security algorithm transmitted by the terminal is available to the base station, the base station may determine that it is capable of performing encryption on the terminal's identifier.

[0262] According to one embodiment, in operation 1630, the base station may transmit confidentiality indication information to the terminal. Operation 1630 may include all of the operation contents according to operation 410 of FIG. 4, operation 510 of FIG. 5, operation 610 of FIG. 6, operation 720 of FIG. 7, and operation 830 of FIG. 8.

[0263] The confidentiality indication information may include information indicating that the base station can perform encryption on the terminal identifier and information regarding the security algorithm used by the base station to encrypt the terminal identifier.

[0264] If the base station determines that it is capable of performing encryption on the terminal's identifier based on the confidentiality application request received in operation 1620, it may transmit confidentiality indication information.

[0265] According to one embodiment, in operation 1640, the terminal may transmit a confidentiality response to the base station. Operation 1640 may include all of the operations according to operation 520 of FIG. 5 and operation 630 of FIG. 6. Operation 1640 may be an operation selectively performed according to the terminal's selection or a predetermined condition between the base station and the terminal.

[0266] Based on the received confidentiality indication information, the terminal may determine whether it can identify the encrypted terminal identifier by the base station. For example, if the terminal can use any of the security algorithms included in the confidentiality indication information, the terminal may determine that it can identify the encrypted terminal identifier. If the terminal determines that it can identify the encrypted terminal identifier by the base station, it may transmit a confidentiality response according to operation 1640.

[0267] According to one embodiment, at operation 1650, the base station may receive a paging trigger from a network device. Operation 1650 may include all of the contents according to operation 210 of FIGS. 2A and 2B.

[0268] In one embodiment, at operation 1660, the base station may determine whether to encrypt the first identifier of the terminal. The first identifier may be a type of identifier of the terminal, for example, the full-RNTI of the terminal.

[0269] The base station may decide to encrypt the first identifier of the terminal if the confidentiality application indicator instructs to perform encryption of the identifier of the terminal.

[0270] If the confidentiality application indicator indicates that the identifier of the terminal should be selectively encrypted, the base station may determine to encrypt the first identifier of the terminal based on whether the terminal satisfies at least one confidentiality requirement. For example, if the base station determines that the RRC inactivity state of the terminal has been exceeded for a certain period of time, the base station may determine to encrypt the first identifier of the terminal. For example, if the base station determines that the paging first identifier has been used exceeding a predetermined number of times, the base station may determine to encrypt the first identifier. If the first identifier has been used for a certain period of time without being updated, the base station may determine to encrypt the identifier of the terminal.

[0271] According to one embodiment, in operation 1670, if the base station determines to encrypt the first identifier of the terminal, the base station may generate a second identifier. The base station may generate the second identifier based on the first identifier. The base station may encrypt the first identifier based on security context information included in the confidentiality policy information to generate the second identifier.

[0272] In one embodiment, although not shown in the drawing, if the base station does not perform encryption directly, the base station may transmit information for encryption to an adjacent base station (e.g., a second base station (122)).

[0273] If the base station determines not to encrypt the first identifier, the base station may not perform encryption on the first identifier.

[0274] According to one embodiment, in operation 1680, the base station may perform a paging procedure. Operation 1680 may include all of the operation contents corresponding to operation 230.

[0275] In one embodiment, although not illustrated in the drawing, the base station may transmit or receive a message for changing the RRC state of the terminal based on the second identifier. For example, the base station may receive an RRC reconnection request message including the second identifier from the terminal. For example, the base station may transmit an RRC release message including the second identifier to the terminal.

[0276] It should be noted that the configuration diagrams, exemplary diagrams of control / data signal transmission / reception methods, and exemplary diagrams of operating procedures illustrated in FIGS. 1 through 16 are not intended to limit the scope of the embodiments of the present disclosure. That is, not all components, entities, or operational steps described in FIGS. 1A through 6 should be construed as essential components for the implementation of the disclosure, and implementations may be made within a scope that does not detract from the essence of the disclosure even if only some components are included.

[0277] The operations of the embodiments described above can be realized by providing a memory device storing the corresponding program code in any component within the device. That is, the control unit within the device can execute the operations described above by reading and executing the program code stored in the memory device through a processor or a CPU (Central Processing Unit).

[0278] The various components and modules of the entity or terminal device described in the present disclosure may be operated using hardware circuits, such as logic circuits based on complementary metal oxide semiconductors, firmware, software, and / or hardware and firmware and / or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and application-specific semiconductors.

[0279] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0280] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0281] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0282] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0283] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0284] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

[0285] The following description is provided in detail to facilitate easy implementation by those skilled in the art. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. In the description of the drawings, the same or similar reference numerals may be used to refer to identical or similar components. Furthermore, in the drawings and related descriptions, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

Claims

1. In a wireless communication system, a method of operating a first base station, The action of transmitting confidentiality instruction information to UE (user equipment). An operation of generating a second identifier based on the above confidentiality instruction information, and Including an operation of transmitting a paging message including the second identifier to a second base station, The above confidentiality instruction information includes information indicating that the first identifier can be encrypted, A method in which the second identifier is generated by encrypting the first identifier of a UE in an RRC (radio resource control) inactive state.

2. In claim 1, the method: comprising the action of receiving a confidentiality response from said UE; A method wherein the confidentiality response includes information indicating that the UE can identify the second identifier.

3. In claim 2, The above confidentiality instruction information includes information about at least one security algorithm that the first base station can use to encrypt the first identifier, A method wherein the confidentiality response includes information about an algorithm selected by the UE from among the at least one security algorithm.

4. In claim 1, The operation of transmitting the above confidentiality instruction information to the UE is: An action for receiving a confidentiality application request from the UE; An operation for generating the confidentiality instruction information based on the above confidentiality application request, and Including an operation of transmitting the generated confidentiality instruction information to the UE, The above confidentiality application request includes information about at least one security algorithm available to the UE, A method wherein the confidentiality instruction information includes one of the at least one security algorithm.

5. In claim 1, the method: An operation for receiving confidentiality policy information from a network device, and Including an operation of transmitting confidentiality instruction information to the UE based on the confidentiality policy information; A method wherein the confidentiality policy information includes information regarding at least one confidentiality requirement and a confidentiality application indicator indicating whether confidentiality is applied.

6. In claim 5, The above confidentiality application directive is either a first directive that instructs to apply confidentiality, a second directive that instructs to apply confidentiality optionally, or a third directive that instructs not to apply confidentiality. A method wherein the at least one confidentiality requirement includes at least one of: when the RRC inactivity state of the UE is maintained for a first time period or longer; when the first identifier is used a predetermined number of times or longer; and when the time for which the first identifier is used exceeds a second time period.

7. In claim 6, the method: An action to identify that the above confidentiality application directive is the above second directive, and A method comprising the action of generating the second identifier if the UE satisfies at least one confidentiality requirement.

8. In claim 1, the method: A method including an operation of generating the second identifier by encrypting only the bits corresponding to the identification information of the UE among the plurality of bits constituting the first identifier.

9. In claim 1, the method: Including an action of transmitting an RRC release message to the UE, A method wherein the RRC release message includes the second identifier.

10. In claim 1, the method: Including an operation of receiving an RRC reconnection request message from the UE; A method wherein the RRC reconnection request message includes the second identifier.

11. In a wireless communication system, a method of operating a UE (user equipment), The action of receiving confidentiality instruction information from a base station; An operation of receiving a paging message including a second identifier from a base station, and Including an action to identify information indicating that the first identifier included in the above confidentiality instruction information can be encrypted; A method wherein the second identifier is generated by encrypting the first identifier.

12. In claim 11, the method: comprising the action of transmitting a confidentiality response to the base station; The confidentiality instruction information includes information about at least one security algorithm that the base station can use to encrypt the first identifier, A method according to claim 1, wherein the confidentiality response comprises at least one of information indicating that the UE can identify the second identifier or information regarding an algorithm selected by the UE from among the at least one security algorithm.

13. In claim 11, The operation of receiving the above confidentiality instruction information from the base station is: An action of transmitting a request for confidentiality application to the above base station; Including an operation of receiving the confidentiality instruction information generated based on the confidentiality application request, The above confidentiality application request includes information about at least one security algorithm available to the UE, A method wherein the confidentiality instruction information includes one of the at least one security algorithm.

14. In claim 11, the method: An operation of receiving an RRC release message from the base station; or Including an action of transmitting an RRC reconnection request message to the above base station, The above RRC release message includes the second identifier, A method wherein the RRC reconnection request message includes the second identifier.

15. In a wireless communication system, in a first base station device, Department of Communications; storage; At least one processor connected to the communication unit and the storage unit, wherein the at least one processor: Transmit confidentiality instruction information to UE (user equipment), Based on the above confidentiality instruction information, a second identifier is generated, Transmitting a paging message including the second identifier to the second base station, The above confidentiality instruction information includes information indicating that the first identifier can be encrypted, A device wherein the second identifier is generated by encrypting the first identifier of a UE in an RRC (radio resource control) inactive state.

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