Method and apparatus for providing ue policy in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. A method performed by a first policy control function (PCF) entity for user equipment in a wireless communication system comprises the steps of: transmitting a first message for requesting registration to a binding support function (BSF) entity; transmitting, to the BSF entity, a second message for requesting subscription to an event in which a second PCF for session management is registered with the BSF entity; receiving, from the BSF entity, a third message for notifying that the second PCF has been registered with the BSF entity; and transmitting, to the second PCF, a fourth message for requesting a report on whether a protocol data unit (PDU) session or packet data network (PDN) connection for user equipment capable of receiving a terminal policy in an evolved packet system (EPS) is ongoing.

Description

Method and device for providing terminal policy in a wireless communication system

[0001] The present disclosure relates to a method and apparatus for providing a terminal policy (UE Policy) in a wireless communication system or a mobile communication system, and more particularly, to a method and apparatus for providing a terminal policy in a composite mobile communication system having different communication protocols.

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

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

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

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

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

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

[0008] 5GS, which is currently being commercialized, and the LTE and LTE-A systems that provide mobile communication services are both mobile communication systems that provide packet-based services. 5GS is being developed to support interworking with the Evolved Packet System (EPS), an evolutionary packet system based on LTE and LTE-A. In a 5G system, the 5G core network provides UE policies to terminals.

[0009] In a 5G system, when a UE capable of using wireless communication via 5GS and EPS is connected to a network via 5GS that supports EPS / 5GS interworking and then moves the network connection to EPS, the 5G core network no longer provides a new terminal policy to the UE, and the UE communicates with the network based on the terminal policy provided by the core network before moving to EPS.

[0010] In a 5G system, if a change occurs in the terminal policy and / or terminal policy-related information in the 5G core network after an EPS / 5GS interworking terminal moves from 5GS to EPS, there is a problem in that the changed terminal policy cannot be transmitted to the terminal through the EPS entity.

[0011] Accordingly, the present disclosure provides a method and device for providing a terminal policy to a terminal when the terminal moves from 5GS to EPS in a 5G system supporting EPS / 5GS interworking.

[0012] Additionally, the present disclosure provides a method and device for selecting a session to be used for providing terminal policy to a terminal when the terminal moves from 5GS to EPS in a 5G system supporting EPS / 5GS interworking.

[0013] The present disclosure relates to a method for processing a control signal in a wireless communication system, which may include: receiving a first control signal transmitted from a network entity; processing the received first control signal; and transmitting a second control signal generated based on the processing to the network entity.

[0014] According to various embodiments of the present disclosure, a device and method for providing a terminal policy to a terminal when the terminal moves from 5GS to EPS in a 5G system supporting EPS / 5GS interworking can be provided.

[0015] According to the devices and methods according to various embodiments of the present disclosure, when a change in terminal policy occurs in a core network while a terminal is connected to an EPS, the terminal can receive the changed terminal policy without having to move to 5GS again, thereby reducing resource waste and preventing incorrect network access, thereby improving communication stability.

[0016] In addition, the effects that can be obtained from the present disclosure are not limited to the effects mentioned above, 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.

[0017] FIG. 1 is a diagram illustrating a network structure and interface of a 5G system according to one embodiment of the present disclosure.

[0018] FIG. 2 is a diagram illustrating a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0019] FIG. 3 is a diagram illustrating a network structure and interface related to a policy control and rate control system of a 5G system according to one embodiment of the present disclosure.

[0020] FIG. 4 is a diagram illustrating a method for a core network to transmit a terminal policy to a terminal in an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0021] FIG. 5 illustrates the structure of an SMF+PGW-C (500) according to one embodiment of the present disclosure.

[0022] FIG. 6 illustrates the structure of a PCF (600) according to one embodiment of the present disclosure.

[0023] FIG. 7 illustrates the structure of a UE according to one embodiment of the present disclosure.

[0024] FIG. 8 illustrates the structure of a network entity according to one embodiment of the present disclosure.

[0025] To meet the growing demand for wireless data traffic following the commercialization of 4G communication systems, efforts are being made to develop improved 5G or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are also referred to as "Beyond 4G Network" or "Post-LTE" systems. The 5G communication system specified by 3GPP is called the New Radio (NR) system.

[0026] To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band). To mitigate radio path loss and increase the transmission range of radio waves in ultra-high frequency bands, beamforming, massive MIMO (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies have been discussed and applied to NR systems in 5G communication systems.

[0027] Additionally, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation are being developed in 5G communication systems.

[0028] In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed in 5G systems.

[0029] Meanwhile, the Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components, such as objects. The Internet of Everything (IoE) is also emerging, combining IoT technologies with big data processing technologies, such as those connected to cloud servers. To implement the IoT, technological elements such as sensing technologies, wireless and wired communication and network infrastructure, service interface technologies, and security technologies are required. Recently, research is being conducted on technologies such as sensor networks, Machine-to-Machine (M2M), and Machine-Type Communication (MTC) for connecting objects. In the IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects to create new value for human life. IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services through the convergence and integration of existing IT (Information Technology) technologies with various industries.

[0030] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, 5G communication such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented using techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN), a big data processing technology described above, can also be considered an example of the convergence of 5G and IoT technologies.

[0031] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. At this time, it should be noted that the same components in the attached drawings are represented by the same reference numerals as much as possible. In addition, it should be noted that the attached drawings of the present disclosure are provided to help understand the present disclosure, and the present disclosure is not limited to the forms or arrangements illustrated in the drawings. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted. It should be noted that in the following description, only the parts necessary for understanding the operation according to various embodiments of the present disclosure will be described, and the description of other parts will be omitted so as not to distract from the gist of the present disclosure. In addition, although the present disclosure describes various embodiments using terminology used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), this is merely an example for explanation. The various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0032] FIG. 1 is a diagram illustrating a network structure and interface of a 5G system according to one embodiment of the present disclosure.

[0033] A network entity included in the network structure of the 5G system of Fig. 1 may include a network function (NF) depending on the system implementation.

[0034] Referring to FIG. 1, the network structure of a 5G system (100) may include various network entities. For example, the 5G system (100) may include an authentication server function (AUSF) (108), an access and mobility management function ((core) access and mobility management function (AMF)) (103), a session management function (SMF) (105), a policy control function (PCF) (106), an application function (AF) (107), a unified data management (UDM) (109), a data network (DN) (110), a network exposure function (NEF) (113), and a network slicing selection function (NSSF) (114). It may include an edge application service domain repository (EDR) (not shown), an edge application server (EAS, not shown), an EAS discovery function (EASDF, not shown), a user plane function (UPF) (104), a (radio) access network ((R)AN) (102), and a terminal, i.e., a user equipment (UE) (or terminal) (101).

[0035] Each NF of the 5G system (100) supports the following functions.

[0036] AUSF (108) can process and store data for authentication of UE (101).

[0037] AMF (103) provides functions for access and mobility management per UE, and one UE can be connected to one AMF by default. Specifically, the AMF (103) provides signaling between CN nodes for mobility between 3GPP access networks, termination of a radio access network (RAN) CP interface (i.e., N2 interface), termination of non-access stratum (NAS) signaling (N1), NAS signaling security (NAS ciphering and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE reachability (including control and performance of paging retransmission), mobility management control (subscription and policy), intra-system mobility and inter-system mobility support, support for network slicing, SMF selection, lawful intercept (for AMF events and interfaces to the LI system), provision of forwarding of session management (SM) messages between UE and SMF, transparent proxy for SM message routing, access authentication, access authorization including roaming authorization check. It may support functions such as authorization, provision of SMS message transmission between UE and SMSF, security anchor function (SAF), and / or security context management (SCM). Some or all of the functions of AMF (103) may be supported within a single instance of one AMF.

[0038] DN (110) may represent, for example, an operator service, an Internet connection, or a third-party service. DN (110) may transmit a downlink protocol data unit (PDU) to UPF (104) or receive a PDU transmitted from UE (101) from UPF (104).

[0039] PCF (106) may receive information about packet flow from an application server and provide a function for determining policies such as mobility management and session management. Specifically, PCF (106) may support functions such as supporting a unified policy framework for controlling network operations, providing policy rules so that control plane functions (e.g., AMF, SMF, etc.) can enforce the policy rules, and implementing a front end for accessing related subscription information for policy determination within a user data repository (UDR).

[0040] SMF (105) provides a session management function, and when a UE has multiple sessions, each session can be managed by a different SMF. Specifically, the SMF (105) may support functions such as session management (e.g., session establishment, modification, and termination, including tunnel maintenance between UPF (104) and (R)AN (102) nodes), UE IP address allocation and management (optionally including authentication), selection and control of UP functions, traffic steering setup to route traffic from UPF (104) to appropriate destinations, termination of interfaces to policy control functions, enforcement of policy and quality of service (QoS) control portions, lawful intercept (for SM events and interfaces to LI systems), termination of SM portions of NAS messages, downlink data notification, initiator of AN specific SM information (forwarded to (R)AN (102) via N2 via AMF (103)), determination of SSC mode of sessions, roaming functions, etc. Some or all of the functions of SMF (105) may be supported within a single instance of an SMF.

[0041] UDM (109) stores user subscription data, policy data, etc. UDM (109) may include two parts, namely, an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

[0042] The FE may include a UDM FE, which is responsible for location management, subscription management, and credential processing, and a PCF, which is responsible for policy control. The UDR may store data required for the functions provided by the UDM-FE and policy profiles required by the PCF. The data stored in the UDR may include user subscription data and policy data, including subscription identifiers, security credentials, access and mobility-related subscription data, and session-related subscription data. The UDM-FE may access subscription information stored in the UDR and support functions such as authentication credential processing, user identification handling, access authentication, registration / mobility management, subscription management, and SMS management.

[0043] UPF (104) can transmit a downlink PDU received from DN (110) to UE (101) via (R)AN (102), and can transmit an uplink PDU received from UE (101) via (R)AN (102) to DN (110). Specifically, the UPF (104) may support functions such as an anchor point for intra / inter RAT mobility, an external PDU session point for interconnection to the Data Network, a user plane portion of packet routing and forwarding, packet inspection and policy rule enforcement, an uplink classifier to support lawful intercept, traffic usage reporting, routing of traffic flows to the Data Network, a branching point to support multi-homed PDU sessions, QoS handling for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement), uplink traffic validation (service data flow (SDF) to QoS flow mapping), transport level packet marking in uplink and downlink, downlink packet buffering and downlink data notification triggering. Some or all of the functions of UPF (104) may be supported within a single instance of a UPF.

[0044] The AF (107) can interact with the 3GPP core network to provide services (e.g., support functions such as application impact on traffic routing, access to network capability exposure, and interaction with policy frameworks for policy control).

[0045] (R)AN(102) may be a general term for a new radio access network that supports both evolved E-UTRA, an evolved version of 4G radio access technology, and new radio (NR) (e.g., gNB).

[0046] The gNB provides functions for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to the UE in uplink / downlink (i.e., scheduling), IP (internet protocol) header compression, encryption and integrity protection of user data streams, selection of an AMF upon attachment of the UE if routing to the AMF is not determined from the information provided to the UE, routing of user plane data to UPF(s), routing of control plane information to the AMF, connection setup and teardown, scheduling and transmission of paging messages (originating from the AMF), scheduling and transmission of system broadcast information (originating from the AMF or operating and maintenance (O&M)), measurement and measurement reporting setup for mobility and scheduling, transport level packet marking in uplink, session management, support for network slicing, and QoS flows. It can support functions such as mapping to management and data radio bearers, support for UEs in inactive mode, distribution of NAS messages, NAS node selection, sharing of radio access networks, dual connectivity, and tight interworking between NR and E-UTRA.

[0047] UE (101) refers to a user equipment. The user equipment may be referred to by terms such as terminal, mobile equipment (ME), or mobile station (MS). Furthermore, the user equipment may be a portable device such as a laptop, mobile phone, personal digital assistant (PDA), smartphone, or multimedia device, or may be a non-portable device such as a personal computer (PC) or vehicle-mounted device.

[0048] The NEF (113) may provide a means for securely exposing services and capabilities provided by 3GPP network functions, for example, for third parties, internal exposure / re-exposure, application functions, and edge computing. The NEF (113) receives information from other NF (s) (based on the exposed capability (s) of other NF (s)). The NEF (113) may store the received information as structured data using a standardized interface to a data storage network function. The stored information may be re-exposed to other NF (s) and AF (s) by the NEF (113) and may be used for other purposes, such as analysis.

[0049] NRF (115) can support service discovery functionality. It receives NF discovery requests from NF instances and provides information about discovered NF instances to the NF instances. It also maintains available NF instances and the services they support.

[0050] Meanwhile, for convenience of explanation, FIG. 1 illustrates a reference model for a case where a UE (101) accesses one DN (110) using one PDU session, but the present disclosure is not limited thereto.

[0051] A UE (101) can access two (i.e., local and central) data networks simultaneously using multiple PDU sessions. In this case, two SMFs can be selected for different PDU sessions. However, each SMF can have the ability to control both the local UPF and the central UPF within the PDU session.

[0052] Additionally, the UE (101) may simultaneously access two (i.e., local and central) data networks provided within a single PDU session.

[0053] NSSF (114) can select a set of network slice instances serving UE (101). In addition, NSSF (114) can determine the allowed NSSAI (network slice selection assistance information) and, if necessary, perform mapping to subscribed single-network slice selection assistance information (S-NSSAI). In addition, NSSF (114) can determine the configured NSSAI and, if necessary, perform mapping to subscribed S-NSSAI. In addition, NSSF (114) can determine the set of AMFs used to serve UE or, depending on the configuration, can inquire NRF (115) to determine a list of candidate AMFs.

[0054] NRF (115) supports service discovery. It receives NF discovery requests from NF instances and provides information about discovered NF instances to the NF instances. It also maintains available NF instances and the services they support.

[0055] In the 3GPP system, a conceptual link connecting NFs within a 5G system is defined as a reference point. The following illustrates a reference point included in the 5G system architecture depicted in Figure 1.

[0056] - N1: Reference point between UE and AMF

[0057] - N2: Reference point between (R)AN and AMF

[0058] - N3: Reference point between (R)AN and UPF

[0059] - N4: Reference point between SMF and UPF

[0060] - N5: Reference point between PCF and AF

[0061] - N6: Reference point between UPF and data network

[0062] - N7: Reference point between SMF and PCF

[0063] - N8: Reference point between UDM and AMF

[0064] - N9: Reference point between two core UPFs

[0065] - N10: Reference point between UDM and SMF

[0066] - N11: Reference point between AMF and SMF

[0067] - N12: Reference point between AMF and AUSF

[0068] - N13: Reference point between UDM and authentication server function (AUSF)

[0069] - N14: Reference point between two AMFs

[0070] - N15: Reference point between PCF and AMF for non-roaming scenarios, reference point between PCF and AMF in visited network for roaming scenarios.

[0071] In the following description, the term "terminal" may refer to UE (101), and the terms "UE" and "terminal" may be used interchangeably. In this case, unless specifically defined additionally, the term "terminal" should be understood as "UE (101).

[0072] URSP RulesPTraffic Descriptor (TD)PRoute Selection Component (RSC)APPID, DNN, IP, FQDN, CCS-NSSAIDNNSSC ModePDU-TypeAccess-Type1App#11S-NSSAI#1DNN#1SSC#3IPv43GPP2App#21S-NSSAI#2DNN#2SSC#1IPv4 / v63GPP2S-NSSAI#2DNN#2--Non-3GPP4App#1, CC=internet, supl1S-NSSAI#1DNN#1--Non-3GPP5App#3, CC=ims1S-NSSAI#3DNN#3--Multi-Access6App#11S-NSSAI#1DNN#1--Multi-Access7*(match all)1S-NSSAI#4DNN#4SSC#3--

[0073] Table 1 shows an example of a URSP rule.

[0074] In 5GC, PCF can provide policy information to UE, and UE policy information can include UE Route Selection Policy (URSP).

[0075] URSP is used by the UE to determine whether an application detected by the UE can be associated with an already established PDU Session, offloaded to a non-3GPP access outside the PDU Session, routed through a ProSe Layer-3 UE-to-Network Relay outside the PDU Session, or established and associated with a new PDU Session. A URSP can consist of one or more URSP rules, and a URSP rule can consist of a Traffic Descriptor and one or more Route Selection Components (RSCs). [Table 1] shows an example of a URSP rule.

[0076] A Traffic Descriptor (TD) may contain matching criteria that can identify detected applications or application traffic. Specific examples include:

[0077] a) Application descriptor: Can indicate the terminal's application. For example, the application descriptor can include an APPID composed of the OSID and OSAPPID.

[0078] b) IP descriptor: Displays the IP address that represents the destination address of the IP packet transmitted from the terminal. It can include an IP 3-tuple, i.e., the IP destination address, port number, and protocol.

[0079] c) Domain descriptor: Indicates the destination address of the server to which the terminal connects in FQDN (Fully Qualified Domain Name) format.

[0080] d) Non-IP descriptor: Can indicate the recipient of Non-IP data.

[0081] e) DNN: Can represent the data network name.

[0082] f) Connection Capability (CC): This corresponds to the type information that can specify the characteristics of the connected traffic, and can have values ​​such as IMS (IP Multimedia Subsystem), MMS (Multimedia Message Service), and Internet.

[0083] A Route Selection Component (RSC) may contain attribute information of a PDU Session to determine which PDU Session to associate an application or application traffic with when a traffic descriptor that can identify an application detected by the terminal is specified. Specific examples are as follows.

[0084] a) SSC Mode Selection: This is an element that indicates session and service continuity and can have values ​​such as SSC Mode 1, SSC Mode 2, and SSC Mode 3.

[0085] b) Network Slice Selection: Can indicate network slices.

[0086] c) DNN Selection: Can indicate the data network name.

[0087] d) PDU Session Type Selection: You can indicate the type of PDU-Session that can be IPv4, IPv6 or IPv4v6, or Ethernet, Non-IP.

[0088] e) Non-Seamless Offload indication: This may indicate that the application's traffic can be offloaded through non-3GPP access that exists outside the PDU session.

[0089] f) ProSe Layer-3 UE-to-Network Relay Offload indication: This may indicate that the application's traffic can be offloaded through a ProSe Layer-3 UE-to-Network Relay that exists outside the PDU session.

[0090] g) Access Type preference: This can indicate whether the PDU session is a PDU session connected via 3GPP access, a session connected via Non-3GPP access, or a session that supports Multi-Access connection using both 3GPP access and Non-3GPP access.

[0091] h) PDU Session Pair ID: Application traffic can indicate an identifier shared in a redundant PDU Session.

[0092] i) RSN (Redundancy Sequence Number): This can indicate an identifier used in redundant transmission.

[0093] Multiple URSP rules (USRP rules) may be divided within a Policy Section (PS) of a UE Policy Container. In one embodiment of the present disclosure, multiple URSP rules may be divided and placed within multiple Policy Sections so as not to exceed the maximum allowable transmission size of the NAS layer. A single URSP rule may not be divided and placed across two PSs. A complete URSP rule may be included in a single Policy Section.

[0094] USRP rules have priorities for each rule. According to one embodiment of the present disclosure, each URSP rule may include a URSP rule identifier that can identify the URSP rule. More specifically, the URSP rule identifier may refer to traffic parameters that enable a terminal to distinguish a terminal application.

[0095] FIG. 2 is a diagram illustrating a network structure and interface of a wireless communication system (e.g., EPS / 5GS interworking system) according to one embodiment of the present disclosure.

[0096] 5GS may include a New Radio (NR) base station (NG-RAN (radio access node) or gNB (next generation node B)) (204) for wireless access of a terminal (UE) (201b), an access and mobility management function (AMF) (205), and, in addition, although not shown in FIG. 2, may include a session management function (SMF), a user plane function (UPF), a policy control function (PCF), a network slice selection function (NSSF), and / or a unified data management (UDM), a unified data repository (UDR), etc.

[0097] The EPS may include an E-UTRA base station (E-UTRAN (Evolved UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network) or eNB (evolved node B)) (202) for wireless access of a terminal (UE) (201a), a mobility management entity (MME) (203), a serving gateway (SGW) (206), a packet data network gateway (PGW) (the PGW may be composed of a PGW-U and a PGW-C), a policy and charging rule function (PCRF), and / or a home subscriber server (HSS).

[0098] According to one embodiment, the AMF (205) and the MME (203) may be Network Functions (NFs) that manage wireless network access and mobility for terminals. The SMF, SGW, and PGW are NFs that manage sessions for terminals, and the session information may include Quality of Service (QoS) information, charging information, and / or packet processing information. In addition, the UPF and PGW are NFs that process user plane traffic (e.g., User Plane traffic) and may be controlled by the SMF and SGW. The PCF and PCRF may be NFs that manage operator policies and / or PLMN policies for providing services in a wireless communication system. In addition, the PCF may be divided into a PCF that is responsible for Access and Mobility (AM) policies and UE policies, and a PCF that is responsible for Session Management (SM) policies. The PCF in charge of AM / UE policy and the PCF in charge of SM policy may be logically or physically separate NFs, or may be a single NF logically or physically. The UDM and HSS may be NFs that store and manage subscriber information (UE subscription) of terminals. The UDR may be an NF or database (DB) that stores and manages data. The UDR (212) may store subscription information of terminals and provide the subscription information of terminals to the UDM. In addition, the UDR (212) may store operator policy information and provide the operator policy information to the PCF. The NSSF may be an NF that performs the function of selecting network slice instances that serve terminals or determining NSSAI (Network Slice Selection Assistance Information).

[0099] An instance is a state in which an NF exists in the form of software code, and physical and / or logical resources are allocated from a computing system (e.g., a specific computing system existing on a core network) to perform the function of the NF, thereby enabling the execution of the function of the NF. For example, an AMF Instance, an SMF Instance, an NSSF Instance, etc. may mean a state in which physical and / or logical resources can be allocated and used from a specific computing system existing on a core network for the operations of AMF, SMF, NSSF, etc. Therefore, when a physical AMF, SMF, or NSSF device exists, and an AMF Instance, SMF Instance, or NSSF Instance that is allocated and uses physical and / or logical resources from a specific computing system existing on a network for the operations of AMF, SMF, or NSSF can perform the same operations.

[0100] The UDM of 5GS and the HSS of EPS can be configured as one combo node (referred to as UDM+HSS) (211). The UDM+HSS node (211) can store subscriber information of the terminal. The SMF of 5GS and the PGW-C of EPS can be configured as one combo node (referred to as SMF+PGW-C) (208). The PCF of 5GS and the Policy Control and Charging Rules Function (PCRF) of EPS can be configured as one combo node (referred to as PCF+PCRF). The UPF of 5GS and the PGW-U of EPS can be configured as one combo node (referred to as UPF+PGW-U) (207). The terminal can access the MME (203) of EPS through the E-UTRA base station to use the EPS network service. Additionally, terminals can access the 5GS AMF (205) via the NR base station and utilize 5GS network services. In Figure 2, the same reference numerals are used for terminals connected to EPS and terminals connected to 5GS. This indicates that the terminals can access either EPS or 5GS.

[0101] In this way, one NF or network entity can support different network systems simultaneously, and such NF, network node, or network entity can be called a combo node, combo NF, combined node, integrated NF, interworking node, interworking NF, etc. as described above. In addition, the function of the NF exemplified as a combo node can also be implemented through interworking between two or more network entities. In addition, for convenience of illustration and explanation, an NF that supports different network systems simultaneously can be indicated using the "+" symbol or the " / " symbol. For example, when SMF and PGW-C are configured as one combo node, it can be expressed as PGW-C / SMF, PGW-C+SMF, SMF / PGW-C, or SMF+PGW-C.

[0102] Terminals (201a, 201b) can establish a session by connecting to a data network (e.g., a network providing Internet services) through the 5GS or EPS system. At this time, the terminals can distinguish each data network using an identifier called a data network name (DNN) or an access point name (APN). To distinguish the data networks, the 5GS can use a DNN, and the EPS can use an APN. The DNN and the APN can be used to determine the NF, the interface between NFs, and the operator policy related to the user plane when the terminal connects to the network system and the session. The DNN and the APN can be understood as equivalent information and can convey the same information. The DNN can be used, for example, to select an SMF and UPF(s) for a PDU session, and can be used to select an interface(s) (e.g., N6 interface) between the data network and the UPF for the PDU session. Additionally, DNN can be used to determine the mobile operator's policy to apply to a PDU session.

[0103] In the following embodiments, combo nodes such as UDM+HSS node, PCF+PCRF node, SMF+PGW-C node, UPF+PGW-C node, etc. are described by omitting the name of “node” for convenience of explanation. In addition, in the following embodiments, the definition of a message defined in one embodiment can be applied with the same meaning in other embodiments that utilize the same message.

[0104] The PCF can be divided into a session management-policy control function (SM-PCF) (210) responsible for session management policy (SM Policy) and a terminal-policy control function (UE-PCF) (209) responsible for mobility management policy (AM Policy) and / or terminal policy (UE Policy). The SM-PCF (210) can be connected to the SMF (208) via the N7 interface, but cannot be connected to the AMF (205). In other words, the SM-PCF (210) cannot support the N15 interface. The UE-PCF (209) can be connected to the AMF (205) via the N15 interface, but cannot be connected to the SMF (208). In other words, the UE-PCF (209) cannot support the N7 interface. The SM-PCF and the UE-PCF can be physically and / or logically located in one device or one PCF, but can be distinguished as different PCF instances.

[0105] The UE Policy provided by the PCF to the UE may include an Access Network Discovery & Selection Policy (ANDSP), a UE Route Selection Policy, a Vehicle-to-everything (V2X) Policy, and / or a ProSe Policy.

[0106] Access Network Discovery & Selection Policy (ANDSP): May contain policy information required when a terminal selects a non-3GPP access network.

[0107] UE Route Selection Policy (URSP): May contain policy information required to route traffic going out of the terminal.

[0108] V2X Policy (V2XP): May include policy information that provides configuration parameters required for a terminal to perform V2X communication.

[0109] ProSe Policy (ProSeP): May include policy information that provides configuration parameters required for a terminal to perform ProSe Direct Discovery, ProSe Direct Communication, ProSe UE-to-Network Relay, and Remote UE communication.

[0110] FIG. 3 is a diagram illustrating a network structure and interface related to a policy control and rate control system of a 5G system according to one embodiment of the present disclosure.

[0111] The policy control function (PCF) (304) can serve as an integrated control framework that controls network operations.

[0112] The application function (AF) (305) can provide session-related information to the billing function to support rule creation.

[0113] The Network Data Analytics Function (NWDAF) (306) can collect data from any NF included in the core network. At this time, the NWDAF and the counterpart NF must belong to the same PLMN.

[0114] The Unified Data Repository (UDR) (307) may provide subscription data, policy data, structured data for exposure, and / or application data to the UDM (not shown), PCF (304), NEF (308), etc.

[0115] The network exposure function (NEF) (308) can serve to securely expose network services and functions.

[0116] The charging function (CHF) (309) communicates with the 5G core network and can provide a charging system related to the use of network resources.

[0117] A single PCF instance cannot support both N15 and N7 simultaneously.

[0118] - N15: Reference point between AMF (302) and PCF (304)

[0119] - N7: Reference point between SMF (303) and PCF (304)

[0120] - N4: Reference point between SMF (303) and UPF (301)

[0121] - N5: Reference point between AF (305) and PCF (304)

[0122] - N23: Reference point between NWDAF (306) and PCF (304)

[0123] - N36: Reference point between UDR (307) and PCF (304)

[0124] - N30: ​​Reference point between NEF (308) and PCF (304)

[0125] - N29: Reference point between NEF (302) and SMF (303)

[0126] - N28: Reference point between CHF (309) and PCF (304)

[0127] - N40: Reference point between CHF (309) and SMF (303)

[0128] - N101: Reference point between PCF instance supporting N15 and PCF instance supporting N7

[0129] - N102: Reference point between PCF and SMF supporting N15

[0130] FIG. 4 is a diagram illustrating a method by which a core network conveys terminal policies to a terminal in a wireless communication system (e.g., an EPS / 5GS interworking system) according to one embodiment of the present disclosure. More specifically, this diagram illustrates a method by which a network determines which PDN connection to convey terminal policies through when a terminal moves from 5GS to EPS.

[0131] 1. In 5GS, a UE Policy Association can be established between the AMF and the UE-PCF, and the UE-PCF can provide terminal policies to the UE through the AMF. The UE and the UE-PCF can exchange information about whether the UE supports receiving terminal policies through EPS and whether the network supports providing terminal policies through EPS. The UE-PCF may also be referred to as PCF for the UE, PCF for UE Policy, etc.

[0132] 2. UE-PCF can register with BSF (Binding Support Function) that it is PCF in charge of UE Policy for UE. UE-PCF can register with BSF using Nbsf_Management_Registration message, and can provide at least one of Subscription Permanent Identifier (SUPI), whether it supports function to provide terminal policy through EPS (“URSP Provisioning in EPS Support”), and list of DNN and S-NSSAI combination(s) that make up URSP Rule that UE-PCF provided to UE in step 1.

[0133] 2a. The UE-PCF may request a subscription from the BSF so that it can be notified when an event occurs in which a PCF responsible for a policy (e.g., UE Policy, AM Policy, SM Policy) for the UE indicated by the SUPI in step 2 is registered with the BSF. Alternatively, the UE-PCF may request a subscription from the BSF so that it can be notified when an event occurs in which a PCF responsible for a PDU Session or PDN Connection consisting of a DNN and S-NSSAI combination(s) for the UE indicated by the SUPI in step 2 is registered with the BSF. Step 2a may be performed simultaneously with or separately from step 2.

[0134] 3. SMF+PGW-C and SM-PCF (PCF for the PDU Session) can establish SM Policy Association during the PDU Session Establishment / Modification procedure in 5GS. SM-PCF can be referred to as PCF for the PDU Session, PCF for the SMF, PCF for SM, or PCF for SM Policy.

[0135] 4. The SM-PCF can register with the BSF that it is in charge of policy management of the PDU Session for the corresponding SUPI by using the SUPI of the UE associated with the PDU Session that is the target of step 3, the DNN of the corresponding PDU Session, and the S-NSSAI combination. The Nbsf_Management_Registration message can be used. At this time, the SM-PCF can additionally provide the BSF with the PDU Session ID and / or the DNN and S-NSSAI combination(s) of the PDU Session (all or part if there are more than one) for the corresponding SUPI. If the SM-PCF corresponds to the same PCF as the UE-PCF, step 4 can be performed in the form of updating the registered content in the BSF (the Nbsf_Management_Update message can be used). If the SM-PCF and the UE-PCF correspond to the same PCF, this can indicate that the SM-PCF and the UE-PCF are logically or physically one NF (Network Function).

[0136] 5. Based on the subscription request of the UE-PCF in steps 2 to 2a, the BSF may notify the UE-PCF that an event has occurred in which the PCF responsible for policy management of the PDU Session for the UE has registered with the BSF. This notification may use the Nbsf_Management_Notify message, and the ID of the corresponding PCF, i.e. the ID of the SM-PCF, may be provided.

[0137] 6. The UE-PCF may request the SM-PCF indicated by the PCF ID received in step 5 to report whether a PDU Session or PDN Connection for a UE that can receive UE Policy from EPS is ongoing (not released). This request for reporting may be performed by notifying that a Policy Control Request Trigger (PCRT) should be applied to the SMF+PGW-C. In addition, the UE-PCF may provide the SM-PCF with a PDU Session ID and / or a DNN and S-NSSAI combination to which PCRT should be applied. The PDU Session ID and / or a DNN and S-NSSAI combination provided at this time may be the information notified by the BSF in step 5. The information that the UE-PCF provides to the SM-PCF in step 6 may have been previously provided to the BSF by the UE-PCF in step 2. In this case, the BSF may provide the SM-PCF with a response message when the SM-PCF sends a registration request to the BSF in step 4, in which case step 6 may be omitted. If the SM-PCF and the UE-PCF are the same PCF and the UE-PCF can recognize this fact, the operation of sending a request to the SM-PCF in step 6 may be omitted or performed internally.

[0138] 7. If SM-PCF receives the request in step 6 (or if it received the request in step 4), it may provide a PCRT requesting the SMF+PGW-C to report whether the PDU Session or PDN Connection for the UE that can receive UE Policy is ongoing (or not released). For example, it may provide a PCRT indicating that “the PDU Session for providing URSP in EPS is ongoing”, or “the RAT Type has changed”. Even if SM-PCF does not receive the request in step 6, if SM-PCF determines that the PDU Session for the UE can be reported to the PDN Connection when the UE moves from 5GS to EPS based on the session management policy, it can provide the SMF+PGW-C with a PCRT notifying “RAT Type has changed”, and if it can determine through other procedures that the UE can be provided with UE Policy through EPS, it can provide the SMF+PGW-C with a PCRT notifying “PDU Session for providing URSP in EPS is continuing” or a PCRT notifying “RAT Type has changed”.The SMF+PGW-C, which has been provided with at least one of the two PCRTs, may perform the actions of notifying the SM-PCF that the RAT Type of the UE has changed from NR (or may be any other 5G RAT Type) to E-UTRAN (or may be any other EPS RAT Type), and / or providing a combination of PDU Session ID and / or DNN and S-NSSAI so that the SM-PCF can recognize that the PDU Session continues as a PDN Connection, when the UE moves from 5GS to EPS while the PDU Session for the associated UE is not released in step 3 and the corresponding PDU Session continues as a PDN Connection in EPS. In this case, the PDU Session and / or the combination of DNN and S-NSSAI may be information received from the UE-PCF in step 6, information received from the BSF in step 4, or information determined by the SM-PCF based on another session management policy. When there is one or more target PDU Sessions to which the UE-PCF applies PCRT, the UE-PCF may select as the target PDU Session a PDU Session for which it has previously provided a UE Policy (or UE Policy Container), a PDU Session managed by SM-PCF and / or SMF+PGW-C for which it has previously provided a UE Policy (or UE Policy Container), a PDU Session associated with the default PDN connection, a PDU Session that can be determined based on network settings, or one of them randomly, or select all PDU Sessions as the target PDU Session.

[0139] 8. UE can move connection from 5GS to EPS.

[0140] 9. A procedure to move from 5GS to EPS (with or without N26 connection) may be initiated between the UE and the network.

[0141] 10. During the procedure of moving from 5GS to EPS, SMF+PGW-C can determine whether the condition of PCRT is satisfied as described in step 7, and can inform SM-PCF whether a PDU Session or PDN Connection for a UE that can receive UE Policy is ongoing and provide the ID of the corresponding PDU Session. For example, SMF+PGW-C can inform that the condition “A PDU Session for providing URSP in EPS is ongoing” is satisfied and provide the PDU Session ID and / or a combination of DNN and S-NSSAI constituting the corresponding PDU Session, or can inform that the condition “RAT Type has changed” is satisfied and provide the PDU Session ID and / or a combination of DNN and S-NSSAI constituting the corresponding PDU Session. When the SMF+PGW-C notifies the SM-PCF of the satisfaction of a condition and provides the PDU Session ID and / or the combination of DNN and S-NSSAI that constitute the corresponding PDU Session, the SMF+PGW-C may additionally provide information on whether the SMF+PGW-C corresponds to an SMF+PGW-C that can convey UE Policy via EPS. For example, this may be information indicating “5GS to EPS mobility” (this information may be included in the UE Policy Container). The SMF+PGW-C may refer to the following information when determining whether to provide the SM-PCF with information on whether the SMF+PGW-C corresponds to an SMF+PGW-C that can convey UE Policy via EPS.For example, (1) if SMF+PGW-C determines that it can transmit / receive signaling messages using ePCO (Extended Protocol Configuration Options) (or PCO (Protocol Configuration Options)) as a result of prior negotiation / determination with SWG, MME, and / or UE, (2) if it determines that it can transmit / receive using UE Policy (UE Policy may be included in a UE Policy Container) based on ePCO (or PCO), (3) if PCRT indicating “PDU Session for providing URSP in EPS is ongoing” is applied in step 7, and / or (4) if ePCO including UE Policy Container is received from UE in step 9, it may decide to provide information notifying “5GS to EPS mobility” (may be included in a UE Policy Container) to SM-PCF. The ePCO (or PCO) is a field used to transmit / receive information related to protocol settings that need to be exchanged between the UE and the PGW (or SMF+PGW-C), and may be in the form of a container whose contents cannot be interpreted by E-UTRAN, MME, SGW, etc. connecting the UE and the PGW (or SMF+PGW-C). The UE Policy Container may be provided as one of the contents of the ePCO (or PCO) when the UE and / or SMF+PGW-C transmit / receive it to / from each other. Based on this information, in step 14 described below, the UE-PCF and / or SM-PCF may consider whether the SMF+PGW-C corresponds to an SMF+PGW-C that can transmit the UE Policy via EPS when determining the target PDN Connection or target SMF+PGW-C to which the UE Policy is to be transmitted via EPS.When a PDU Session leads to a PDN Connection, SMF+PGW-C can determine the S-NSSAI based on the APN corresponding to the DNN when determining the DNN and S-NSSAI that constitute the PDN Connection. At this time, if more than one S-NSSAI can be allowed for one APN, SMF+PGW-C can select one of the allowed S-NSSAIs and provide it when reporting to SM-PCF. If SMF+PGW-C cannot receive UE Policy through steps 11 to 14 described below (for example, this may be a case where a failure or rejection message is received from UE-PCF due to inability to establish UE Policy Association through SM-PCF and / or inability to provide UE Policy information), SMF+PGW-C can select another S-NSSAI allowed for the APN and report the combination of DNN and S-NSSAI again to receive UE Policy. If a default PDN Connection for a UE is connected, SMF+PGW-C may determine the default PDN Connection as the target of UE Policy transmission and provide the corresponding DNN, S-NSSAI combination when reporting to SM-PCF. If there is one or more PDU Sessions / PDN Connections that satisfy the PCRT condition, SM+PGW-C may include information (which may be included in the UE Policy Container) indicating “5GS to EPS mobility” in the report for all or part of the PDU Sessions / PDN Connections.For example, if there is one or more target PDU Sessions that satisfy PCRT, SMF+PGW_C may select as target PDU Sessions a PDU Session for which UE Policy (or UE Policy Container) has been previously provided, a PDU Session managed by SM-PCF and / or SMF+PGW-C for which UE Policy (or UE Policy Container) has been previously provided, a PDU Session associated with a default PDN connection, a PDU Session that can be determined based on network settings, a random one, or all PDU Sessions. SMF+PGW-C may use the Npcf_SMPolicyControl_Update Request message in step 10.

[0142] 11. Based on the message in step 10, the SM-PCF can determine that the corresponding PDU Session is continuing from the EPS to the PDN Connection and that UE policy can be provided to the UE using it through the EPS entities. For example, this may be the case when it is reported that the PCRT condition “PDU Session to provide URSP in EPS is continuing” is satisfied in step 10, or a UE Policy Container is received, or information indicating “movement from 5GS to EPS (5GS to EPS mobility)” is received. The SM-PCF can request the UE-PCF ID from the BSF to search for the UE-PCF that was in charge of the corresponding UE Policy in 5GS. The Nbsf_Management_Discovery Request message can be used for this. This message can include at least one of SUPI, information indicating that UE Policy can be provided from EPS, and the ID of the PDU Session to be used for UE Policy provision (and / or a combination of the DNN and S-NSSAI constituting the PDU Session). If the SM-PCF and the UE-PCF are PCFs of the same logical or physical network function and the SM-PCF is aware of this fact, the SM-PCF may omit step 11.

[0143] 12. The BSF may provide the ID of the UE-PCF, which is the PCF responsible for the UE policy corresponding to the information provided in step 11.

[0144] 13. The SM-PCF may request the UE-PCF received in step 12 to establish a UE Policy Association in order to provide UE Policy in EPS. This request may include at least one of the SUPI used in steps 10 and 11, the PDU Session ID (and / or the combination of DNN and S-NSSAI constituting the PDU Session), the UE Policy Container received in step 10, and the information indicating “5GS to EPS mobility” received in step 10. The UE-PCF may restore the UE Policy information and PCRT for the corresponding UE from the UDR based on the information received in step 13 (e.g., the SUPI, the PDU Session ID (and / or the combination of DNN and S-NSSAI constituting the PDU Session), the UE Policy Container, and the information indicating “5GS to EPS mobility”). This information may be information generated in 5GS before steps 8 and 9. When the UE-PCF receives a PDU Session ID (and / or a combination of DNN and S-NSSAI that constitute a PDU Session), it knows that the UE Policy should be delivered via the PDN Connection corresponding to that PDU Session while the UE is in the EPS, and if there are multiple PDU Sessions (or PDN Connections) for that SUPI, it knows that this PDU Session (or PDN Connection) should be selected as the target of the UE Policy delivery.If the UE-PCF determines that the PDU Session (or its corresponding PDN Connection) indicated by the combination of PDU Session ID, DNN, and S-NSSAI provided by the SM-PCF is not suitable for the target session to which UE Policy is to be delivered via EPS, the UE-PCF may send a rejection to the SM-PCF, stating that the UE Policy cannot be provided for the corresponding UE (the UE indicated by the SUPI provided by the SM-PCF) or that the UE Policy cannot be provided through the corresponding PDU Session of the corresponding UE (the PDU Session indicated by the combination of PDU Session ID, DNN, and S-NSSAI provided by the SM-PCF). Additionally, the UE-PCF may inform the SM-PCF whether it can retry step 13 with another SUPI or another combination of PDU Session ID, DNN, and S-NSSAI (e.g., retry is allowed, do not retry). If the SM-PCF and the UE-PCF are the same PCF and the SM-PCF is aware of this fact, the action that the SM-PCF requests the UE-PCF to perform may be omitted, and the action that the UE-PCF should perform may be performed by the SM-PCF.

[0145] 14. UE-PCF can forward UE Policy to SMF+PGW-C via SM-PCF. UE Policy can be provided in the form of a UE Policy Container. SM-PCF can use the Npcf_SMPolicyControl_Update Response message when forwarding to SMF+PGW-C. If the SM-PCF receives a rejection from the UE-PCF due to the inability to provide UE Policy for the UE (the UE indicated by the SUPI provided by the SM-PCF), or due to the inability to provide UE Policy through the PDU Session of the UE (the PDU Session indicated by the PDU Session ID, DNN and S-NSSAI combination provided by the SM-PCF), or receives an indication that step 13 can be retried with a different SUPI or a different PDU Session ID, DNN and S-NSSAI combination, the SM-PCF may perform step 11 or step 13 again using a different SUPI or a different PDU Session ID, DNN and S-NSSAI combination received in step 10. If the SM-PCF receives a rejection from the UE-PCF due to the inability to provide UE Policy for the UE (the UE indicated by the SUPI provided by the SM-PCF) or due to the inability to provide UE Policy through the PDU Session of the UE (the PDU Session indicated by the PDU Session ID, DNN, and S-NSSAI combination provided by the SM-PCF), it may not perform step 11 or step 13 again if it is notified not to retry step 13 with a different SUPI or a different PDU Session ID, DNN, and S-NSSAI combination.If the SM-PCF and the UE-PCF are the same PCF and the SM-PCF is aware of this, the operation that the SM-PCF requests the UE-PCF to perform can be omitted, and the operation that the UE-PCF should perform can be performed by the SM-PCF. The SMF+PGW-C can provide the UE Policy (or the UE Policy Container containing it) to the UE through the SGW, MME, and E-UTRAN. In this case, the UE Policy (or UE Policy Container) can be provided through the ePCO.

[0146] 15. The UE can store the UE Policy provided from the EPS network and establish a PDN Connection based on it.

[0147] FIG. 5 illustrates a structure of a session management function + packet data network gateway control entity (SMF+PGW-C) (500) according to one embodiment of the present disclosure. The structure may be a network entity that performs a session management function and a packet data network gateway control function (Packet Data Network Gateway-Control, PGW-C). The SMF+PGW-C (500) may be a concept that includes the SMF of the 5GS and the PGW-C of the EPS as a single combo node. As shown in FIG. 5, the SMF+PGW-C (500) of the present disclosure may include at least one controller (processor) (510), and a transceiver (520) including a receiver and a transmitter. The SMF+PGW-C (500) may include a memory (not shown). The transceiver (520) and memory may be connected to at least one controller (510) so as to operate under the control of at least one controller (510).

[0148] At least one controller (510) can control a series of processes so that the application functions described in FIGS. 1 to 4 of the present disclosure can be performed. The transceiver (520) can transmit and receive signals with the terminal and other network devices (e.g., 600). The signals can include control messages, data information, etc.

[0149] FIG. 6 illustrates the structure of a PCF (600) according to one embodiment of the present disclosure. The structure may be an entity that performs a policy control function. The PCF (600) may be divided into an SM-PCF that is responsible for a session management policy (SM Policy) and a UE-PCF that is responsible for a mobility management policy (AM Policy) and / or a terminal policy (UE Policy). The SM-PCF and the UE-PCF may be configured as separate devices, and even if configured as the same device, they may be configured to be logically separated. As shown in FIG. 6, the PCF (600) of the present disclosure may include at least one controller (processor) (610), and a transceiver (620) including a receiver and a transmitter. The application function may include a memory (not shown). The transceiver (620) and the memory may be connected to at least one controller (610) so as to operate under the control of the at least one controller (610).

[0150] At least one controller (610) can control a series of processes so that the application functions described in FIGS. 1 to 4 of the present disclosure can be performed. The transceiver (620) can transmit and receive signals with the terminal and other network devices (e.g., 500). The signals can include control messages, data information, etc.

[0151] The network device of the present disclosure may include all devices corresponding to network functions such as AUSF, NEF, NF, UDM, AMF, UPF, SMF, NRF, PCF, SMF+PGW-C, UPF+PGW-U, SM-PCF, UE-PCF, UDM+HSS, UDR, etc., and each network function may be configured independently.

[0152] FIG. 7 illustrates the structure of a UE according to one embodiment of the present disclosure.

[0153] Referring to FIG. 7, a terminal according to one embodiment may include a transceiver (710), a memory (720), and a processor (730). The transceiver (710), the memory (720), and the processor (730) of the UE may operate according to the communication method of the terminal described above. However, the components of the terminal are not limited thereto. For example, the terminal may include more or fewer components than those described above. In addition, the processor (730), the transceiver (710), and the memory (720) may be implemented as a single chip. In addition, the processor (730) may include at least one processor. In addition, the terminal of FIG. 7 may correspond to the terminals of FIGS. 1, 2, and 4.

[0154] The transceiver (710) collectively refers to the UE receiver and the UE transmitter, and can transmit and receive signals with a base station or network entity. The signals transmitted and received with the base station or network entity may include control information and data. The transceiver (710) may include an RF transmitter for up-converting and amplifying the frequency of a transmission signal, and an RF receiver for low-noise amplification and down-converting the frequency of a reception signal. However, this is only an example of the transceiver (710), and the components of the transceiver (710) are not limited to the RF transmitter and RF receiver.

[0155] In addition, the transceiver (710) can receive a signal through a wireless channel and output it to the processor (730), and transmit the signal output from the processor (730) through the wireless channel. The memory (720) can store programs and data necessary for the operation of the UE. In addition, the memory (720) can store control information or data included in a signal acquired by the UE. The memory (720) can be a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0156] The processor (730) can control a series of processes to enable the terminal to operate. For example, the transceiver (710) can receive a data signal including a control signal transmitted by a base station or a network entity, and the processor (730) can determine the result of receiving the control signal and data signal transmitted by the base station or the network entity.

[0157] FIG. 8 illustrates the structure of a network entity according to one embodiment of the present disclosure.

[0158] Referring to FIG. 8, a network entity according to one embodiment may include a transceiver (810), a memory (820), and a processor (830). The transceiver (810), the memory (820), and the processor (830) of the network entity may operate according to the communication method of the network entity described above. However, the components of the network entity are not limited thereto. For example, the network entity may include more or fewer components than the components described above. The processor (830), the transceiver (810), and the memory (820) may be implemented as a single chip. In addition, the processor (830) may include at least one processor. In addition, the network entity of FIG. 8 may correspond to the network entities described in FIGS. 1 to 6.

[0159] The transceiver (810) refers to a receiver and a transmitter, and can transmit and receive signals with a terminal (UE), a base station, or other network entity. The signals transmitted and received with the terminal, base station, or other network entity may include control information and data. The transceiver (810) may include an RF transmitter for up-converting and amplifying the frequency of a transmission signal and an RF receiver for low-noise amplifying and down-converting the frequency of a reception signal. However, this is only an example of the transceiver (810), and the components of the transceiver (810) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (810) may receive a signal through a wireless channel and output it to the processor (830), and transmit a signal output from the processor (830) through the wireless channel.

[0160] The memory (820) can store programs and data necessary for the operation of the network entity. Furthermore, the memory (820) can store control information or data included in signals acquired by the network entity. The memory (820) can be a storage medium such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, a DVD, or a combination of storage media.

[0161] The processor (830) may control a series of processes so that the network entity operates as described above. For example, the transceiver (810) may receive a data signal including a control signal transmitted by a terminal, a base station, or a network entity, and the processor (830) may determine the result of receiving the control signal and data signal transmitted by the terminal, base station, or network entity.

[0162] Meanwhile, the embodiments disclosed in the specification and drawings described above are merely specific examples to easily explain and aid understanding of the present invention, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be interpreted to include all modifications or variations derived based on the technical concept of the present invention, in addition to the embodiments disclosed herein. Furthermore, each of the above embodiments may be combined and operated as needed.

Claims

1. A method performed by a first PCF (policy control function) entity for a user equipment in a wireless communication system, A step of sending a first message to a BSF (binding support function) entity to request registration; A step of sending a second message to the BSF entity requesting subscription to an event registered by the second PCF for session management to the BSF entity; A step of receiving a third message from the BSF entity to notify that the second PCF has been registered with the BSF entity; and A method comprising the step of transmitting a fourth message to the second PCF for requesting a report on whether a PDU (protocol data unit) session or PDN (packet data network) connection for a user terminal capable of receiving a terminal policy in an evolved packet system (EPS) is ongoing.

2. In paragraph 1, The first message above is, A method comprising: supporting a function of providing a terminal policy based on a subscription permanent identifier (SUPI), an evolved packet system (EPS), and including at least one of a list of combinations of a data network name (DNN) and a single-network slice selection assistance information (S-NSSAI).

3. In paragraph 1, The third message above is, A method comprising an identifier indicating the second PCF.

4. In paragraph 1, The fourth message above is, Instructions to apply PCRT (policy control request trigger) to combo nodes of SMF (session management function) entity and PGW-C (packet data network-control plane) entity, A method comprising at least one of a combination of a PDU session identifier, a DNN and a S-NSSAI to which the above PCRT is applied.

5. A method performed by a second PCF for session management in a wireless communication system, Step for establishing a connection between a network entity and a session management policy; A step of sending a first message to a BSF (binding support function) entity to request registration; A step of receiving a second message from a first PCF for a user equipment for requesting a report on whether a PDU (protocol data unit) session or PDN (packet data network) connection for a user equipment capable of receiving a terminal policy in an evolved packet system (EPS) is ongoing; and A method comprising the step of transmitting a third message to the network entity requesting a report on whether the PDU session or the PDN connection is continuing.

6. In paragraph 5, The first message above is, A method comprising at least one of a combination of an identifier of the PDU session, a subscription permanent identifier (SUPI) of a user terminal associated with the PDU session, a data network name (DNN) of the PDU session, and single-network slice selection assistance information (S-NSSAI).

7. In paragraph 5, The second message above is, An instruction to apply PCRT (policy control request trigger) to the above network entity, and Contains at least one of a PDU session identifier to which the above PCRT is applied and a combination of DNN and S-NSSAI, A method wherein the above network entity is a combo node of a session management function (SMF) entity and a packet data network-control plane (PGW-C) entity.

8. In paragraph 7, The above PCRT is, A method comprising a PCRT notifying that a PDU (protocol data unit) session for a user terminal capable of receiving a terminal policy from the above EPS is continued or that a RAT (radio access technology) type of the user terminal is changed.

9. In a first PCF (policy control function) entity for a user equipment in a wireless communication system, Transmitter and receiver; and Including a control unit connected to the above transmitter and receiver, The above control unit: Send a first message to the BSF (binding support function) entity to request registration, To the above BSF entity, the second PCF for session management sends a second message to request subscription to an event registered with the above BSF entity, receiving a third message from the BSF entity to notify that the second PCF has been registered with the BSF entity; and A first PCF configured to transmit a fourth message to the second PCF for requesting a report on whether a PDU (protocol data unit) session or PDN (packet data network) connection for a user terminal capable of receiving a terminal policy in an evolved packet system (EPS) is ongoing.

10. In paragraph 9, The first message above is, A first PCF that supports a function of providing a terminal policy based on a subscription permanent identifier (SUPI), an evolved packet system (EPS), and includes at least one of a list of combinations of a data network name (DNN) and a single-network slice selection assistance information (S-NSSAI).

11. In paragraph 9, The third message above is, A first PCF comprising an identifier pointing to the second PCF.

12. In paragraph 9, The fourth message above is, Instructions to apply PCRT (policy control request trigger) to combo nodes of SMF (session management function) entity and PGW-C (packet data network-control plane) entity, A first PCF comprising at least one combination of a PDU session identifier, a DNN and a S-NSSAI to which the above PCRT is applied.

13. In a second PCF (policy control function) entity for session management in a wireless communication system, Transmitter and receiver; and Including a control unit connected to the above transmitter and receiver, The above control unit: Establishes a connection between network entities and session management policies, Send a first message to the BSF (binding support function) entity to request registration, Receive a second message from a first PCF for a user equipment to request a report on whether a PDU (protocol data unit) session or PDN (packet data network) connection for the user equipment capable of receiving a terminal policy in an evolved packet system (EPS) is ongoing, and A second PCF configured to transmit a third message to the network entity requesting a report on whether the PDU session or the PDN connection is continuing.

14. In paragraph 13, The first message above is, A second PCF including at least one of a combination of an identifier of the PDU session, a subscription permanent identifier (SUPI) of a user terminal associated with the PDU session, a data network name (DNN) of the PDU session, and single-network slice selection assistance information (S-NSSAI).

15. In paragraph 13, The second message above is, An instruction to apply PCRT (policy control request trigger) to the above network entity, and Contains at least one of a combination of a PDU session identifier and a DNN and S-NSSAI for which the above PCRT is applied, The above PCRT includes a PCRT that notifies that a PDU (protocol data unit) session for a user terminal capable of receiving a terminal policy from the EPS continues or that the RAT (radio access technology) type of the user terminal has changed. The above network entity is a second PCF, which is a combo node of a session management function (SMF) entity and a packet data network-control plane (PGW-C) entity.

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