WO2024085655A1

WO2024085655A1 - Method and apparatus for selecting policy control function in wireless communication system supporting interworking between networks

Info

Publication number: WO2024085655A1
Application number: PCT/KR2023/016176
Authority: WO
Inventors: 김동연; 박중신; 이지철
Original assignee: 삼성전자주식회사
Priority date: 2022-10-19
Filing date: 2023-10-18
Publication date: 2024-04-25
Also published as: KR20240054821A

Abstract

The present disclosure relates to a method and apparatus for selecting a policy control function (PCF) in a wireless communication system supporting interworking between different networks, and according to an embodiment of the present disclosure, a method performed by a session management (SM)-PCF in a wireless communication system supporting interworking between a first network and a second network comprises the steps of: receiving a request message for a session management policy modification, the request message including information related to a radio access technology (RAT) change of a user equipment that moves from the first network to the second network, from a first network entity that has received a PDU session establishment request from the user equipment; determining whether a PCF used in the first network for the user equipment is used in the second network; and transmitting, to the first network entity, a response message including related information associated with a user equipment policy, on the basis of the determination.

Description

Method and apparatus for selecting a policy control function in a wireless communication system supporting interworking between networks

This disclosure relates to a method and device for providing UE Policy information in a wireless communication system.

5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and includes sub-6 GHz ('Sub 6GHz') bands such as 3.5 gigahertz (3.5 GHz) as well as millimeter wave (mm) bands such as 28 GHz and 39 GHz. It is also possible to implement it in the ultra-high frequency band ('Above 6GHz') called Wave. In addition, in the case of 6G mobile communication technology, which is called the system of Beyond 5G, Terra is working to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low delay time that is reduced to one-tenth. Implementation in Terahertz bands (e.g., 95 GHz to 3 THz) is being considered.

In the early days of 5G mobile communication technology, there were concerns about ultra-wideband services (enhanced Mobile BroadBand, eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). With the goal of satisfying service support and performance requirements, efficient use of ultra-high frequency resources, including beamforming and massive array multiple input/output (Massive MIMO) to alleviate radio wave path loss and increase radio wave transmission distance in ultra-high frequency bands. Various numerology support (multiple subcarrier interval operation, etc.) and dynamic operation of slot format, initial access technology to support multi-beam transmission and broadband, definition and operation of BWP (Band-Width Part), large capacity New channel coding methods such as LDPC (Low Density Parity Check) codes for data transmission and Polar Code for highly reliable transmission of control information, L2 pre-processing, and dedicated services specialized for specific services. Standardization of network slicing, etc., which provides networks, has been carried out.

Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology, considering the services that 5G mobile communication technology was intended to support, based on the vehicle's own location and status information. V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience, and NR-U (New Radio Unlicensed), which aims to operate a system that meets 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 the terrestrial network is impossible, positioning, etc. Physical layer standardization for technology is in progress.

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

When this 5G mobile communication system is commercialized, an explosive increase in connected devices will be connected to the communication network. Accordingly, it is expected that strengthening the functions and performance of the 5G mobile communication system and integrated operation of connected devices will be necessary. To this end, eXtended Reality (XR) and Artificial Intelligence to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR). , AI) and machine learning (ML), new research will be conducted on 5G performance improvement and complexity reduction, AI service support, metaverse service support, and drone communication.

In addition, the development of these 5G mobile communication systems includes new waveforms, full dimensional MIMO (FD-MIMO), and array antennas to ensure coverage in the terahertz band of 6G mobile communication technology. , multi-antenna transmission technology such as Large Scale Antenna, metamaterial-based lens and antenna to improve coverage of terahertz band signals, high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum), RIS ( In addition to Reconfigurable Intelligent Surface technology, Full Duplex technology, satellite, and AI (Artificial Intelligence) to improve the frequency efficiency of 6G mobile communication technology and system network are utilized from the design stage and end-to-end. -to-End) Development of AI-based communication technology that realizes system optimization by internalizing AI support functions, and next-generation distributed computing technology that realizes services of complexity beyond the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could be the basis for .

5GS (5G system), a network that has recently been commercialized, and LTE (long-term evolution) and LTE-A (LTE-advanced) systems, which are networks currently providing mobile communication services, are all mobile devices that provide packet-based services. It is a communication system. This 5GS is being developed to support interworking with the Evolved Packet System (EPS) based on LTE and LTE-A. In this disclosure, the 5GS may be referred to as a 5G system. In the 5G system, the 5G core (5GC) network can provide UE Policy to the terminal.

In the 5G system, interworking between EPS and 5GS can be supported for terminals that can use wireless communication through 5GS and/or EPS. When such a terminal is connected to the EPS network and then to the 5GS network (i.e., when the terminal moves from EPS to 5GS), the old PCF (policy) that provided UE policy information to the terminal from EPS In a situation where a control function exists, the AMF of 5GS selects a new PCF for the terminal. In this case, since multiple PCFs, including an old PCF and a new PCF, exist for one terminal, a conflict may occur in terminal policy information provided to the terminal.

Therefore, the present disclosure provides a method and device for selecting a PCF in a wireless communication system supporting interworking between different networks.

Additionally, the present disclosure provides a method and device for efficiently/stablely selecting a PCF when the network connection of a terminal moves from EPS to 5GS in a wireless communication system supporting interworking between EPS and 5GS.

According to an embodiment of the present disclosure, a method performed in an access and mobility management function (AMF) in a wireless communication system supporting interworking between a first network and a second network includes moving from the first network to the second network. A process of receiving a terminal registration request message from a terminal, and based on first address information related to a first interface for accessing the first PCF (policy control function) used in the first network, to the first PCF A process of obtaining second address information related to a second interface for access, a process of performing a policy association establishment procedure for the first PCF based on the second address information, and the terminal in the second network A process of transmitting a request message containing information related to a radio access technology (RAT) change of the terminal to a first network entity that manages a protocol data unit (PDU) session for the terminal, and from the first network entity, the terminal It includes the process of receiving a response message containing policy-related information.

In addition, according to an embodiment of the present disclosure, in a wireless communication system supporting interworking between a first network and a second network, an access and mobility management function (AMF) is implemented by a transceiver and, through the transceiver, from the first network to the Receives a terminal registration request message from a terminal moving to a second network, and based on first address information related to the first interface for accessing the first policy control function (PCF) used in the first network, 1 Obtain second address information related to the second interface for accessing the PCF, and based on the second address information, perform a policy association establishment procedure for the first PCF, and through the transceiver, the second Transmits a request message containing information related to a radio access technology (RAT) change of the terminal to a first network entity that manages a protocol data unit (PDU) session for the terminal in a network, through the transceiver, and a processor configured to receive a response message including terminal policy association-related information from the first network entity.

Additionally, according to an embodiment of the present disclosure, a method performed in a session management-policy control function (SM-PCF) in a wireless communication system supporting interworking between a first network and a second network includes, For modifying a session management policy, including information related to a change in radio access technology (RAT) of the terminal, from a first network entity that has received a PDU session establishment request from a terminal moving from the first network to the second network. , a process of receiving a request message, a process of determining whether a policy control function (PCF) used in the first network for the terminal is used in the second network, and terminal policy association-related information based on the determination. It includes the process of transmitting a response message including to the first network entity.

Additionally, according to an embodiment of the present disclosure, a session management-policy control function (SM-PCF) in a wireless communication system supporting interworking between a first network and a second network includes a transceiver, and the Session management, including information related to a change in radio access technology (RAT) of the terminal, from a first network entity that has received a PDU session establishment request from a terminal moving from the first network to the second network through a transceiver. Receiving a request message for policy modification, determining whether a policy control function (PCF) used in the first network for the terminal is used in the second network, and terminal policy association-related information based on the determination and a processor configured to transmit a response message including a response message to the first network entity through the transceiver.

1 is a diagram showing the network structure and interface of a 5G system, according to an embodiment of the present disclosure;

FIG. 2 is a diagram illustrating the network structure and interface of a wireless communication system supporting interworking between EPS and 5GS, according to an embodiment of the present disclosure;

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 an embodiment of the present disclosure;

FIG. 4 is a diagram illustrating a network access procedure in a wireless communication system supporting interworking between EPS and 5GS supporting terminal policy management, according to an embodiment of the present disclosure;

FIGS. 5A, 5B, 5C, 6A, 6B, 6C, 7A, 7B, and 7C are diagrams in a wireless communication system supporting interworking between EPS and 5GS, according to various embodiments of the present disclosure. , drawings showing procedures for managing UE Policy Association during the process of the UE moving core network connection from EPS to 5GS, and

FIG. 8 is a diagram illustrating an example configuration of a network entity in a wireless communication system according to an embodiment of the present disclosure.

In describing the embodiments in this specification, description of technical content that is well known in the technical field to which the present invention belongs and that is not directly related to the present invention will be omitted. This is to convey the gist of the present invention more clearly without obscuring it by omitting unnecessary explanation.

For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings. Additionally, the size of each component does not entirely reflect its actual size. In each drawing, identical or corresponding components are assigned the same reference numbers.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to provide common knowledge in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

At this time, it will be understood that each block of the processing flow diagram diagrams and combinations of the flow diagram diagrams can be performed by computer program instructions. These computer program instructions can be mounted on a processor of a general-purpose computer, special-purpose computer, or other programmable data processing equipment, so that the instructions performed through the processor of the computer or other programmable data processing equipment are described in the flow chart block(s). It creates the means to perform functions. These computer program instructions may also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular manner, so that the computer-usable or computer-readable memory The instructions stored in may also produce manufactured items containing instruction means that perform the functions described in the flow diagram block(s). Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a process that is executed by the computer, thereby generating a process that is executed by the computer or other programmable data processing equipment. Instructions that perform processing equipment may also provide steps for executing the functions described in the flow diagram block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). Additionally, it should be noted that in some alternative execution examples it is possible for the functions mentioned in the blocks to occur out of order. For example, it is possible for two blocks shown in succession to be performed substantially at the same time, or it is possible for the blocks to be performed in reverse order depending on the corresponding function.

At this time, the term '~unit' used in this embodiment refers to software or hardware components such as FPGA or ASIC, and the '~unit' performs certain roles. However, '~part' is not limited to software or hardware. The '~ part' may be configured to reside in an addressable storage medium and may be configured to reproduce on one or more processors. Therefore, as an example, '~ part' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and 'parts' may be combined into a smaller number of components and 'parts' or may be further separated into additional components and 'parts'. Additionally, components and 'parts' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card.

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 indicated by the same symbols whenever possible. In addition, it should be noted that the drawings of the present invention attached below are provided to aid understanding of the present invention, and the present invention is not limited to the form or arrangement illustrated in the drawings of the present invention. Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. It should be noted that in the following description, only the parts necessary to understand the operation according to various embodiments of the present invention will be described, and the description of other parts will be omitted so as not to confuse the gist of the present invention. In addition, the present disclosure describes various embodiments using terms used in some communication standards (eg, 3rd Generation Partnership Project (3GPP)), but this is only an example for explanation. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

In the present disclosure, “A/B”, “A and/or B”, “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, Phrases such as “at least one of A, B, and C” and “at least one of A, B, or C” each refer to any one of the items listed together in that phrase, or all possible combinations thereof. It can be included. Terms such as "first", "second", or "first" or "second" may be used simply to distinguish one component from another, and may refer to that component in other respects, such as importance or order) is not limited.

In the present disclosure, the network technology may refer to standards defined by the ITU (international telecommunication union) or 3GPP (e.g., TS 23.501, TS 23.502, TS 23.503, etc.), and are included in the network structure of FIG. 1, which will be described later. Components may refer to physical entities, software that performs individual functions, or hardware combined with software. In the drawings, reference symbols shown as Nx, such as N1, N2, N3,..., indicate known interfaces between NFs in the 5G core network (CN).

1 is a diagram showing the network structure and interface of a 5G system according to an embodiment of the present disclosure.

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

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

Each NF in the 5G system can support the following functions.

AUSF 108 may process and store data for authentication of UE 101.

The AMF 103 provides functions for UE-level access and mobility management, and each UE can be basically connected to one AMF. Specifically, the AMF 103 supports CN inter-node signaling for mobility between 3GPP access networks, termination of a radio access network (RAN) CP interface (i.e., N2 interface), and non-access stratum (NAS) ) Endpoint of signaling (N1), NAS signaling security (NAS ciphering and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE accessibility ( reachability (including control and performance of paging retransmissions), mobility management control (subscriptions and policies), intra-system mobility and inter-system mobility support, support for network slicing, SMF selection, lawful intercept (LI) (AMF) event and interface to the LI system), providing delivery of session management (SM) messages between the UE and SMF, transparent proxy for routing SM (session management) messages, access authentication (access) authentication, access authorization including roaming authorization checks, provision for delivery of SMS messages between the UE and short message service function (SMSF), security anchor function (SAF), and/or security context management. It can support functions such as SCM). Some or all of the functions of AMF 103 may be supported within a single instance of one AMF.

DN 110 may mean, for example, an operator service, Internet access, or a third party service. The DN 110 may transmit a downlink protocol data unit (PDU) to the UPF 104 or receive a PDU transmitted from the UE 101 from the UPF 104.

The PCF 106 may receive information about packet flow from an application server and provide the function of determining policies such as mobility management and session management. Specifically, PCF 106 supports a unified policy framework to govern network behavior, provides policy rules so that control plane function(s) (e.g., AMF, SMF, etc.) can enforce policy rules, and allows users to It can support functions such as implementing a front end to access relevant subscription information for policy decisions within a user data repository (UDR).

The SMF 105 provides a session management function, and when the UE 101 has multiple sessions, each session can be managed by a different SMF. Specifically, SMF 105 performs session management (e.g., session establishment, modification, and termination, including maintaining tunnels between UPF 104 and (R)AN 102 nodes), UE IP address allocation, and management (optionally including authentication), selection and control of user plane (UP) functions, establishment of traffic steering to route traffic to appropriate destinations in UPF 104, and policy control functions. Termination of interfaces, enforcement of policies and control portion of quality of service (QoS), lawful interception (LI) (for SM events and interfaces to LI systems), termination of SM portion of NAS messages, downlink data notification. notification), AN (access network) initiator of specific SM information (delivered to (R)AN (102) via N2 via AMF (103)), Session and Service Continuity (SSC) mode It can support functions such as decision making and roaming functions. Some or all of the functions of SMF 105 may be supported within a single instance of one SMF.

The UDM 109 may store user subscription data, policy data, etc. UDM 109 may include two parts: an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

The front end (FE) (not shown) may include a UDM FE responsible for location management, subscription management, and credential processing, and a PCF responsible for policy control. UDR can store data required for functions provided by UDM-FE and policy profiles required by PCF. Data stored within 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. UDM-FE accesses subscription information stored in UDR and supports functions such as authentication credential processing, user identification handling, access authentication, registration/mobility management, subscription management, and SMS management. You can.

The UPF (104) delivers the downlink PDU received from the DN (110) to the UE (101) via the (R)AN (102) and receives it from the UE (101) via the (R)AN (102). One uplink PDU can be delivered to the DN 110. Specifically, the UPF 104 is an anchor point for intra/inter RAT mobility, an external PDU session point for interconnect to a data network, packet routing and forwarding, and packet inspection ( User plane portion of inspection and policy rule enforcement, lawful intercept, traffic usage reporting, and uplink classifier to support routing of traffic flows to the data network, multi-homed Branching points to support PDU sessions, QoS handling for the user plane (e.g. packet filtering, gating, uplink/downlink rate enforcement), uplink traffic verification (service data) It can support functions such as flow (service data flow (SDF) mapping between SDF and QoS flow), transport level packet marking in uplink and downlink, downlink packet buffering, and downlink data notification triggering function. Some or all of the functions of UPF 104 may be supported within a single instance of one UPF.

AF 107 supports 3GPP for service provision (e.g., supporting functions such as application influence on traffic routing, access to network capability exposure, and interaction with policy frameworks for policy control). It can interoperate with the core network.

(R)AN 102 supports both evolved E-UTRA (evolved E-UTRA), which is an evolved version of 4G radio access technology, and new radio (NR) (e.g., gNB). A general term for a new wireless access network.

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

UE 101 may refer to a user device. A user device may be referred to by terms such as terminal, mobile equipment (ME), mobile station (MS), etc. Additionally, the user device may be a portable device such as a laptop, a mobile phone, a personal digital assistant (PDA), a smartphone, or a multimedia device, or it may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device.

NEF 111 is provided by 3GPP network functions, e.g., 3rd party, internal exposure/re-exposure, application functions, edge computing. It can provide a means to safely expose services and capabilities for. NEF 111 may receive information (based on the exposed capability(s) of the other NF(s)) from other NF(s). NEF 111 may store received information as structured data using standardized interfaces to data storage network functions. The stored information can be re-exposed by the NEF 111 to other NF(s) and AF(s) and used for other purposes such as analysis.

NRF 115 may support service discovery functions. An NF discovery request can be received from an NF instance, and information on the discovered NF instance can be provided to the NF instance. Additionally, it can maintain available NF instances and the services they support.

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

UE 101 may access two (i.e., local and central) data networks simultaneously, for example, using multiple PDU sessions. At this time, two SMFs may be selected for different PDU sessions. However, each SMF may have the ability to control both the local UPF and the central UPF within the PDU session.

Additionally, UE 101 may simultaneously access, for example, two (ie, local and central) data networks provided within a single PDU session.

NSSF 114 may select a set of network slice instances serving UE 101. Additionally, the NSSF 114 may determine permitted network slice selection assistance information (NSSAI) and, if necessary, perform mapping on subscribed single-network slice selection assistance information (S-NSSAI). Additionally, the NSSF 114 may determine the configured NSSAI and, if necessary, perform mapping to the subscribed S-NSSAIs. Additionally, the NSSF 114 may determine the set of AMFs used to serve the UE, or, depending on settings, may query the NRF 115 to determine a list of candidate AMFs.

In the 3GPP system, the conceptual link connecting NFs in the 5G system is defined as a reference point. The following illustrates reference points included in the 5G system architecture represented in Figure 1.

- N1: Reference point between UE and AMF

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

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

- N4: Reference point between SMF and UPF

- N5: Reference point between PCF and AF

- N6: Reference point between UPF and data network

- N7: Reference point between SMF and PCF

- N8: Reference point between UDM and AMF

- N9: Reference point between two core UPFs

- N10: Reference point between UDM and SMF

- N11: Reference point between AMF and SMF

- N12: Reference point between AMF and AUSF

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

- N14: Reference point between two AMFs

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

In the following description, the terminal may refer to the UE 101, and the terms UE and terminal may be used interchangeably. In this case, unless the terminal is specifically defined additionally, it can be understood as the UE (101).

Table 1 below shows an example of a UE Route Selection Policy (URSP) rule.

[Table 1]

In 5GC, the PCF may provide policy information to the UE 101, and the UE policy information may include the URSP.

URSP is used by the UE (101) and determines whether the application detected by the UE (101) can be associated with an already established PDU Session, can be offloaded to non-3GPP access that exists outside the PDU Session, or is not available outside the PDU Session. It can be used to determine whether it can be routed through an existing ProSe Layer-3 UE-to-Network Relay, or whether a new PDU Session can be established and associated with the application. URSP can be composed of one or more URSP rules, and one URSP rule can be composed of one Traffic Descriptor and one or more Route Selection Components (RSC).

A traffic descriptor (TD) may include matching criteria that can identify the application or traffic of the application detected by the terminal 101. Specific examples are as follows:

Application descriptor: Information that can refer to the application of the terminal 101. For example, the application descriptor may include an APPID consisting of OSID and OSAPPID.

IP descriptor: Displays an IP address indicating the destination address of the IP packet transmitted by the terminal 101. The IP descriptor may include an IP 3-tuple, that is, IP destination address, port number, and protocol.

Domain descriptor: Expresses the destination address of the server to which the terminal 101 connects, for example, in FQDN (Fully Qualified Domain Name) format.

Non-IP descriptor: Information that can specify the recipient of Non-IP data.

DNN: This is the name of the data network.

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

The route selection component (RSC) is an attribute of a PDU session for determining which PDU session to associate the application or application traffic with when a traffic descriptor that can identify the application detected by the terminal 101 is specified. May contain information. Specific examples are as follows:

SSC Mode Selection: An element that specifies session and service continuity and can have values such as SSC Mode 1, SSC Mode 2, and SSC Mode 3.

Network Slice Selection: Information that allows you to specify a network slice.

DNN Selection: This is the data network name.

PDU Session Type Selection: This is an element that can specify the type of PDU-Session, which can be IPv4, IPv6 or IPv4v6, Ethernet, or Non-IP.

Non-Seamless Offload indication: Indicates that application traffic can be offloaded through non-3GPP access that exists outside the PDU session.

ProSe (Proximity-services) Layer-3 UE-to-Network Relay Offload indication: Indicates that application traffic can be offloaded through the ProSe Layer-3 UE-to-Network Relay that exists outside the PDU session.

Access Type preference: Whether the PDU session is a PDU session connected through 3GPP access, a session connected through Non-3GPP access, or a session that supports Multi-Access connection using both 3GPP access and Non-3GPP access. It is an element that refers to

PDU Session Pair ID: An element that refers to the identifier shared by application traffic in a redundant PDU Session.

RSN (Redundancy Sequence Number): An element that refers to an identifier used during redundant transmission.

Multiple URSP rules (USRP rules) may be divided within the Policy Section (PS) of the UE Policy Container. In one embodiment of the present disclosure, a plurality of URSP rules may be included in a plurality of Policy Sections so as not to exceed the maximum allowable transmission size of the NAS (Non-Access-Stratum) layer. One URSP rule may not be included because it is divided into two PSs. One complete URSP rule can be included in one Policy Section.

USRP rules may 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 a traffic parameter that allows the terminal 101 to distinguish terminal applications.

FIG. 2 is a diagram illustrating an example of a network structure and interface of a wireless communication system supporting interworking between EPS and 5GS, according to an embodiment of the present disclosure. For the basic functions of the corresponding entity in FIG. 1 among the network entities in FIG. 2, refer to the description of FIG. 1.

5GS includes a New Radio (NR) base station (radio access node (NG-RAN) or next generation node B (gNB)) 204 for wireless access of the terminal (UE) 201b, and an access and mobility management function (access and mobility management function) It may include a mobility management function (AMF) 205, and in addition, a session management function (SMF), a user plane function (UPF), and a policy not shown in FIG. 2 but described in FIG. 1. It may include policy control function (PCF), network slice selection function (NSSF), unified data management (UDM), unified data repository (UDR), etc. You can.

EPS is an E-UTRA base station (Evolved UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network (E-UTRAN), or evolved node B (eNB)) (202) for wireless access of the terminal (UE) (201a), terminal A mobility management entity (MME) 203 that manages the mobility of the (UE) 201a, and a serving gateway (SGW) in charge of the user plane of the terminal (UE) 201a. (206) and a packet data network gateway (PGW) (PGW may be composed of PGW-U (user) and PGW-C (control)), policy and charging rule function for managing policy information ( It may include a policy and charging rule function (PCRF), a home subscriber server (HSS) that manages subscription information of the terminal (UE) 201a, etc.

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

The instance is an NF that exists in the form of software code, and is physically or/from a computing system to perform the function of the NF in a physical computing system (e.g., a specific computing system existing on a core network). It may refer to a state in which logical resources are allocated and the functions of the NF can be executed. For example, AMF Instance, SMF Instance, NSSF Instance, etc. each refer to a state in which physical and/or logical resources can be allocated and used for the operation of AMF, SMF, NSSF, etc. from a specific computing system existing on the core network. You can. Therefore, when a physical AMF, SMF, or NSSF device exists, an AMF Instance, SMF Instance, or NSSF Instance that is allocated and used physical and/or logical resources for AMF, SMF, and NSSF operations from a specific computing system existing on the network. can perform the same operation.

The UDM of 5GS and the HSS of EPS may be composed of one combo node (or combination node) (UDM+HSS) (or HSS+UDM) (211). The UDM+HSS node 211 can store subscriber information of the terminal. The SMF of 5GS and the PGW-C of EPS may be composed of one combo node (referred to as SMF+PGW-C) (or referred to as PGW-C+SMF) (208). 5GS's PCF and EPS's Policy Control and Charging Rules Function (PCRF) can be composed of one combo node (referred to as PCF+PCRF) (or PCRF+PCF). The UPF of 5GS and the PGW-U of EPS may be composed of one combo node (referred to as UPF+PGW-U) (or referred to as PGW-U+UPF) (207). The terminal 201a can access the EPS MME 203 through the E-UTRA base station 202 and use the EPS network service. Additionally, the terminal 201b can connect to the 5GS AMF 205 through the NR base station 204 and use the 5GS network service. In Figure 2, different reference numbers are used for the terminal connected to EPS and the terminal connected to 5GS for convenience.

Terminals

201a and 201b may be the same terminal. This is to indicate that the terminal can connect to EPS or 5GS.

Additionally, in this disclosure, EPS and 5GS may be referred to as a first network and a second network, or may be referred to as a second network and a first network, respectively.

In this way, one NF or network entity can support different network systems simultaneously, and these NFs, network nodes, or network entities can be referred to as the previously described combo node, combo NF, combined node, integrated NF, or interworking. It can be called an (interworking) node, interworking NF, etc. Additionally, the NF function illustrated by the combo node may be implemented through interworking between two or more network entities. In addition, for convenience of illustration and explanation, a "+" symbol or a "/" symbol can be used to indicate NFs that simultaneously support different network systems. For example, if SMF and PGW-C are composed of one combo node, it can be expressed as PGW-C/SMF, PGW-C+SMF, SMF/PGW-C, or SMF+PGW-C.

Terminals

201a and 201b may establish a session by connecting to a data network (eg, an IP network providing Internet service) through 5GS or EPS. At this time, the terminal can distinguish each data network using an identifier called a Data Network Name (DNN) or an Access Point Name (APN). To distinguish data networks, DNN can be used in 5GS and APN can be used in EPS. DNN and APN can be used to determine NFs related to the user plane, interfaces between NFs, operator policies, etc. when a terminal connects a network system and a session. The DNN and the APN can be understood as equivalent information and can deliver the same information. The DNN may be used, for example, to select the SMF and UPF(s) for a PDU session, and may be used to select the interface (e.g., N6 interface) between the data network and the UPF for the PDU session. . Additionally, the DNN can be used to determine the mobile communication service provider's policy to apply to the PDU session.

In the following embodiments, combo nodes such as UDM+HSS node, PCF+PCRF node, SMF+PGW-C node, UPF+PGW-C node, etc. will be described with the name “node” omitted for convenience of explanation. And in the following embodiments, the definition of a message defined in one embodiment may be applied in the same sense to other embodiments that use the same message.

The PCF includes a session management-policy control function (SM-PCF) 210 in charge of the session management policy (SM Policy) and a terminal-policy in charge of the mobility management policy (AM Policy) and/or the terminal policy (UE Policy). It can be divided into control functions (UE-PCF) (209). The SM-PCF (210) can be connected to the SMF (SMF+PGW-C in FIG. 2) 208 through the N7 interface, but cannot be connected to the AMF (205). In other words, SM-PCF 210 cannot support the N15 interface. And the UE-PCF (209) can be connected to the AMF (205) through the N15 interface, but cannot be connected to the SMF (SMF+PGW-C in FIG. 2) (208). In other words, the UE-PCF 209 cannot support the N7 interface. The SM-PCF 210 and UE-PCF 209 may be physically and/or logically located in one device or one PCF, but may be divided into different PCF instances.

The UE Policy provided by the PCF to the UE includes Access Network Discovery & Selection Policy, UE Route Selection Policy, V2X (Vehicle-to-everything) Policy, and/or ProSe Policy may be included.

Access Network Discovery & Selection Policy (ANDSP): Contains policy information required when the terminal selects a non-3GPP access network.

UE Route Selection Policy (URSP): Contains policy information needed to route traffic going out of the UE.

V2X Policy (V2XP): Contains policy information that provides setting parameters necessary for the terminal to perform V2X communication.

ProSe Policy (ProSeP): Contains policy information that provides configuration parameters necessary for the UE to perform ProSe Direct Discovery, ProSe Direct Communication, ProSe UE-to-Network Relay and Remote UE communication.

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 an embodiment of the present disclosure. The basic functions of the corresponding entities in FIGS. 1 and 2 among the network entities in FIG. 3 may refer to the descriptions of FIGS. 1 and 2 .

A policy control function (PCF) 304 may serve as an integrated control framework to control network operations.

The application function (AF) 305 may provide session-related information to the charging function to support rule creation.

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

The Unified Data Repository (UDR) 307 stores subscriber information data (subscription data), policy data (policy data), structured data for exposure, and application data (UDM). (not shown), PCF (304), NEF (308), etc.

The network exposure function (NEF) 308 may play a role in safely exposing network services and functions.

The Charging Function (CHF) 309 communicates with the 5G core network and can provide a charging system related to network resource use.

One PCF instance cannot support N15 and N7 at the same time.

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

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

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

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

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

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

- N30: Reference point between NEF (308) and PCF (304)

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

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

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

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

- N102: Reference point between PCF and SMF supporting N15

FIG. 4 is a diagram illustrating a network access procedure in a wireless communication system supporting interworking between EPS and 5GS supporting terminal policy management, according to an embodiment of the present disclosure.

Figure 4(a) shows the procedure and system structure for a terminal to connect to the core network through an EPS entity (i.e., a network entity in EPS), and Figure 4(b) shows a terminal connecting to the core network from EPS to 5GS. It shows the procedures and system structure of the moving process.

The system structure shown in FIG. 4 is based on the structure of a wireless communication system supporting interworking between EPS and 5GS shown in FIG. 2, and parts not shown or explained in FIG. 4 are shown in FIG. 2. Or you can refer to the explanation.

Meanwhile, depending on settings and/or definitions on the system, all operations described below do not necessarily have to be included, and some operation(s) may be omitted.

Referring to (a) of FIG. 4, in a wireless communication system supporting interworking between EPS and 5GS that supports terminal policy management, the procedure and system structure for the terminal to access the core network through the EPS entity will be described in detail. Do this.

In operation 401, the terminal can access the core network through the MME.

In

operations

402 and 403, if the terminal and/or the core network can transmit/receive a terminal management policy to the terminal through the EPS entity, SMF+PGW-C uses the SM-PCF and the established SM Policy Association to Through the PCF, the UE-PCF can be requested to perform the establishment and management procedures of the UE Policy Association.

Referring to (b) of FIG. 4, in a wireless communication system supporting interworking between EPS and 5GS that supports terminal policy management, the procedure and system structure of the process in which the terminal moves core network access from EPS to 5GS are detailed. It will be explained as follows.

In operation 411, the terminal can access the 5GS core network through AMF.

In operation 412, in the 5GS registration procedure of the terminal, the AMF may perform PCF selection for the AMF to manage the access management policy (AM Policy), and the selected PCF may establish an AM Policy Association with the AMF as an AM-PCF. . Here, the AM-PCF may be the same PCF as the UE-PCF through which the AMF establishes a UE Policy Association to transmit/receive UE Policy information for the UE. Here, the same PCF refers to the same PCF ID, and/ Alternatively, it may mean a PCF that can be identified with the same PCF instance ID.

In operation 413, when the AMF recognizes that the terminal connected to the core network through EPS and then moved to 5GS during the terminal's 5GS registration procedure, AMF determines whether the terminal is managing a session (e.g., PDN Connection) used in EPS or SMF. +You can request a session modification procedure (PDU Session Modification) for PGW-C. SMF+PGW-C can obtain information related to the UE Policy Association through the SM-PCF using the session management policy association modification procedure (SM Policy Association Modification) and transmit it to the AMF. .

In the UE's 5GS registration procedure in operation 414, the AMF notifies the UE of acceptance of the UE's registration request, and then sends/receives UE Policy information for the UE, as described in operation 412. -PCF and UE Policy Association can be established. If the AM-PCF and UE-PCF (referred to as PCF#1) selected as the PCF for AMF in operation 412 and the UE-PCF (referred to as PCF#2) that managed the policy of the UE when the UE is connected through EPS , corresponding to the UE-PCF mentioned in operation 413) are different PCFs, the UDR may receive information related to the UE policy from one or more PCFs responsible for UE policy management for the same UE. Here, the same terminal may mean a terminal identified by the same Subscription Permanent Identifier (SUPI). When a change (including creation, modification, or deletion) occurs in the terminal management policy of the terminal, the UDR may need to determine which PCF among the one or more PCFs should be notified. In addition, UDR is a PCF responsible for post-management when the terminal management policy is not properly delivered to the terminal, and may need to determine which of the one or more PCFs corresponds to this. Additionally, the UDR may need to determine whether the terminal management policy received from any of the one or more PCFs has priority.

In the embodiments of FIGS. 5 to 7 below, for example, when a terminal moves from EPS to 5GS, a method of selecting one PCF in charge of terminal policy management is described. The basic functions of the network entities in the embodiments of FIGS. 5 to 7 below may refer to the descriptions of the corresponding entities in FIGS. 1 to 4 described above. In addition, in the following embodiments of the present disclosure, the PCF used in the EPS connection of the terminal is old UE-PCF (or old AM-PCF/UE-PCF), and the PCF selected when the terminal moves from EPS to 5GS is new UE-PCF ( Or it may be called new AM-PCF/UE-PCF). In the present disclosure, SM-PCF, old UE-PCF (or old AM-PCF/UE-PCF), and new UE-PCF (or new AM-PCF/UE-PCF) are, for example, the first PCF and the second PCF, respectively. and 3rd PCF, or various names may be used to distinguish SM-PCF, old UE-PCF, and new UE-PCF. Additionally, the PCF used in the EPS connection of the terminal may be referred to as PCRF, as shown in the description of FIG. 2.

5A to 5C show UE Policy Association (UE Policy Association) during the process of a UE moving core network access from EPS to 5GS in a wireless communication system supporting interworking between EPS and 5GS according to an embodiment of the present disclosure. ) This is a drawing showing the procedure for managing. More specifically, Figure 5 explains a procedure in which a PCF different from the PCF used in the terminal's EPS connection manages terminal policy association when the terminal connects to 5GS.

Referring to FIG. 5A, in operation 501, the terminal may transmit a registration request message to the AMF through the NG-RAN. In operation 501, the registration request message includes (1) registration type indicating Mobility Registration Update, (2) handover (or mobility) related information indicating that the terminal has moved from the EPS, and (3) stored by the terminal. At least one of the UE Policy Containers containing existing UE policy-related information may be included. The UE policy-related information included in the UE Policy Container may include an indicator (e.g., URSP delivery in EPS Support indication) indicating that the UE can transmit/receive UE policy information through the EPS entity.

In operation 502, the AMF may request information (Context) related to the terminal from the MME. In response to the request, the MME can provide information (Context) related to the terminal to the AMF.

In operation 503, the AMF may select UDM (or UDM+HSS).

In operation 504, the AMF may perform UE context management (UECM) registration as an NF in charge of terminal connection and registration management to the UDM (or UDM+HSS).

In operation 505, the AMF may obtain subscription information (subscription data) of the terminal from UDM (or UDM+HSS) through SDM (subscriber data management) get.

In operation 506, the AMF may select a PCF for the AMF (in other words, a PCF in charge of AM Policy and UE Policy, PCF for AMF) (i.e., new AM-PCF/UE-PCF in FIG. 5A).

In operation 507, the AMF may perform an AM Policy Association establishment procedure for the new PCF (new AM-PCF/UE-PCF) selected in operation 506.

In operation 508, the AMF may transmit a request message to SMF+PGW-C requesting creation of a PDU session. In operation 508, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). For example, NR is provided as the RAT Type to which the terminal is connected, or E-UTRAN (Evolved-Universal Terrestrial Radio Access Network), which is the previous RAT Type that the terminal connected to through EPS, and the terminal is currently connected to through 5GS. A method of providing all NRs of the RAT Type can be used.

In operation 509, the SMF+PGW-C may transmit a request message to the SM-PCF requesting that the SM Policy be modified for the PDN connection corresponding to the PDU session to be created. In operation 509, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). At this time, the information related to the RAT change may include some or all of the information received from the AMF in operation 508, or even if the information related to the RAT change is not received from the AMF, SMF+PGW-C It may include information provided. If the SMF+PGW-C does not receive information related to the RAT change from the AMF, the SMF+PGW-C or any other NF or arbitrary network entity determines and responds to the SM-PCF regarding the RAT change. information can be conveyed.

In operations 510a, 510b, and 510c, the SM-PCF may determine whether a new PCF can be used in 5GS or whether the PCF used in EPS should continue to be used. Some or all of operations 510a, 510b, and 510c may be performed sequentially/selectively or in parallel.

In operation 510a, the SM-PCF can determine whether the UE's movement is inter-system mobility. In other words, SM-PCF can determine that the terminal has moved from EPS to 5GS. Alternatively, SM-PCF can determine whether the UE's movement is inter-RAT mobility. In other words, it can be determined that the terminal has moved from EPS RAT (eg, E-UTRAN) to 5GS RAT (eg, NR).

In operation 510b, the SM-PCF may determine whether a UE Policy Association established for the UE connected to the EPS exists.

In operation 510c, the SM-PCF may determine whether the same PCF as the PCF used in EPS can be used when the terminal moves from EPS to 5GS. In this embodiment, it is assumed that different PCFs are used.

In operation 511, the SM-PCF may transmit a response message to the SM Policy modification request to SM+PGW-C according to the determination results of operations 510a, 510b, and 510c. In the following description, the SM-PCF is described assuming the operation when it is determined that a new PCF (i.e., a different PCF) can be used in 5GS in operations 510a, 510b, and 510c. The operation when it is determined that the PCF used in the EPS will continue to be used will be described in the embodiments of FIGS. 6A to 6C and 7A to 7C, which will be described later. In operation 511, the response message may include information related to UE Policy Association. The information related to the terminal policy association includes (1) the identifier of the UE-PCF used in the EPS, (2) the identifier of the UE Policy Association established in the EPS, and (3) the terminal policy stored by the SM-PCF for the corresponding terminal. Information, (4) At least one of the policy control request triggers stored by the SM-PCF may be included. In the case of the information in (3) and (4) above, the SM-PCF may be information obtained by immediately requesting the UE-PCF to provide it to SM+PGW-C. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

Referring to FIG. 5B, in operation 512, SMF+PGW-C may transmit a response message to the AMF in response to the PDU session establishment request in operation 508. In operation 512, the response message may include information related to UE Policy Association. Information related to UE policy association includes (1) identifier of UE-PCF used in EPS, (2) identifier of UE Policy Association established in EPS, (3) UE policy information stored by SM-PCF, (4) At least one of the policy control request triggers stored by the SM-PCF may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format. The information related to the UE policy association may include at least one of the information received by the SMF+PGW-C from the SM-PCF in operation 511, and if the SMF+PGW-C has a direct association with the UE-PCF may include information received from the corresponding UE-PCF.

At operation 513, the AMF may determine whether a new PCF can be selected in 5GS.

In operation 514, if the AMF determines in operation 513 that a new PCF can be selected in 5GS, it may transmit a request message to SMF+PGW-C requesting a PDU session update. In operation 514, the request message may include an indicator (Indication of UE-PCF change) indicating that a new PCF (eg, UE-PCF) has been selected in 5GS. For example, if the information related to the UE Policy received in operation 512 includes the identifier of the UE-PCF used in EPS, the AMF compares the identifier of the UE-PCF with the identifier of the PCF selected in operation 506. If it is determined that they are different PCFs, an indicator indicating that a new PCF has been selected can be included in the request message.

In operation 515, SMF+PGW-C may transmit a request message to SM-PCF requesting SM Policy modification. In operation 515, the request message may include an indicator indicating that a new PCF has been selected.

In operation 516, the SM-PCF may transmit a request message requesting UE Policy modification to the old UE-PCF used in EPS. In operation 516, the request message may include an indicator that a new PCF has been selected. As an optional embodiment, if the SM-PCF determines in operation 510 that a new PCF can be used in 5GS, operations 511 to 515 may be omitted and operation 516 may be performed immediately. In this case, even if the SM-PCF does not receive an indicator from the AMF and/or SMF+PGW-C indicating that a new PCF has been selected, an indicator indicating that the new PCF has been selected is provided to the UE-PCF at the SM-PCF's discretion. can do.

In operation 517, the old UE-PCF can obtain the latest UE Policy from the UDR through UE Policy Update, or provide the latest UE Policy to the UDR.

In operation 518, the old UE-PCF may respond to the UE Policy modification request in operation 516 by providing the latest UE Policy to the SM-PCF.

In operation 519, the SM-PCF may transmit a response message to the SM Policy modification request in operation 515 to SM+PGW-C. In operation 519, the response message may include information related to UE Policy Association. The information related to the UE policy association includes (1) the identifier of the UE-PCF used in the EPS, (2) the identifier of the UE Policy Association established in the EPS, (3) the UE policy information stored by the SM-PCF, (4) ) At least one of the policy control request triggers stored by the SM-PCF may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 520, SMF+PGW-C may transmit a response message to the PDU session update request in operation 514 to AMF. In operation 520, the response message may include information related to UE Policy Association. Information related to UE policy association includes (1) identifier of UE-PCF used in EPS, (2) identifier of UE Policy Association established in EPS, (3) UE policy information stored by SM-PCF, (4) At least one of the policy control request triggers stored by the SM-PCF may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 521, the SM-PCF may transmit a request message to the old UE-PCF requesting to cancel (delete, terminate) the UE Policy Association between the SM-PCF and the old UE-PCF. In operation 521, the request message may include an indicator indicating that a new PCF has been selected. The SM-PCF can request the old UE-PCF to release the UE Policy Association but maintain the UE Policy data stored in the UDR, and this request is expressed using an indicator indicating that a new PCF has been selected and/or a separate indicator. It can be.

In operation 522, the old UE-PCF may transmit a request message to the UDR requesting unsubscription related to UE Policy data. In operation 522, the request message may include an indicator indicating that a new PCF has been selected. The UE-PCF may request to cancel the subscription related to UE Policy data but maintain the UE Policy data stored in the UDR, and this request may be expressed using an indicator indicating that a new PCF has been selected and/or a separate indicator. there is.

Referring to FIG. 5C, in operation 523, the MME's registration for UDM+HSS may be released.

In operation 524, the MME may request the SGW of the EPS to delete the session.

In operation 525, if the AMF accepts the terminal's registration request for 5GS in operation 501, it may transmit an acceptance message to the terminal.

In operation 526, the AMF may transmit a request message requesting establishment or modification of a UE Policy Association to the newly selected new UE-PCF. The request message in operation 526 may include at least one of (1) information related to UE Policy when provided by the UE to the AMF in operation 501, and (2) a UE Policy Association identifier. The information related to the UE Policy in (1) above may include an indicator indicating that the UE can transmit/receive the UE policy through the EPS entity, and this indicator may be included and provided in the UE Policy Container. The information related to the UE Policy in (1) above may include information received by the AMF in operation 512 and/or operation 520, and this information is provided by the new UE-PCF in operations 528 to 529 to provide the latest information for the UE. It can be considered together when determining UE Policy.

In operation 527, the new UE-PCF may request a subscription related to UE Policy data for UDR.

In operation 528, the new UE-PCF requests and obtains the latest UE Policy data from the UDR (Query), the UDR provides the latest UE Policy data to the new UE-PCF (Notify), or the new UE-PCF notifies the UE. After determining the UE Policy, it can be provided to UDR.

In operation 529, the new UE-PCF may transmit a response message to the UE Policy Association establishment/modification request to the AMF. In operation 529, the response message may include information related to the UE Policy Association. The information related to the UE policy association includes (1) identifier of the new UE-PCF, (2) identifier of the UE Policy Association established between the new UE-PCF and AMF, (3) UE policy information, and (4) policy control request. At least one of the triggers may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 530, the AMF may provide terminal policy information to the terminal. This process can be performed through the UE Configuration Update procedure.

6A to 6C show UE Policy Association (UE Policy Association) during the process of a UE moving core network access from EPS to 5GS in a wireless communication system supporting interworking between EPS and 5GS according to an embodiment of the present disclosure. ) This is a drawing showing the procedure for managing. More specifically, Figures 6a to 6c show a procedure in which the PCF used in the EPS connection of the terminal manages the terminal policy association in 5GS by using the identifier of the PCF used in the EPS connection of the terminal when the terminal connects to 5GS. Explain.

Referring to FIG. 6A, in operation 601, the terminal may transmit a registration request message to the AMF through the NG-RAN. In operation 601, the registration request message includes (1) registration type indicating Mobility Registration Update, (2) handover (or mobility) related information indicating that the terminal has moved from the EPS, and (3) stored by the terminal. At least one of the UE Policy Containers containing existing UE policy-related information may be included. The UE policy-related information included in the UE Policy Container may include an indicator (eg, URSP delivery in EPS Support indication) indicating that the UE can transmit/receive the UE policy through the EPS entity.

In operation 602, the AMF may request information (Context) related to the terminal from the MME. In response to the request, the MME can provide information (Context) related to the terminal to the AMF.

In operation 603, the AMF may select UDM (or UDM+HSS).

In operation 604, the AMF may perform UECM registration with the UDM (or UDM+HSS) as an NF in charge of terminal connection and registration management.

In operation 605, the AMF may obtain subscription information (subscription data) of the terminal from UDM (or UDM+HSS). The information received by the AMF from the UDM includes PCF Selection Assistance Information, and/or the identifier (PCF ID which serving PDN Connection) of the PCF that was managing the PDN Connection for the terminal in the EPS before operation 601. At least one may be included. PCF Selection Assistance Information may consist of a list of DNN and S-NSSAI combination(s) where the PCF for connection management policy control and the PCF for session management policy control may be the same PCF as shown in [Table 2] below. . [Table 2] below shows an example of UE Subscription data types.

[Table 2]

In operation 606, the AMF may select a PCF for AMF (in other words, a PCF in charge of AM Policy and UE Policy, PCF for AMF) (i.e., new AM-PCF/UE-PCF in FIG. 6A).

The operation 606 may include an operation 606a, and when selecting a PCF in the operation 606a, the AMF may refer to the information received from the UDM in the operation 605. For example, if the combination of S-NSSAI and DNN supported by the PDN Connection that the UE wants to move from EPS to 5GS is included in the PCF Selection Assistance Info received in operation 605, AMF sets the session of the PDN Connection. You can reselect the PCF that was in charge of management policy control. At this time, if the information received from the UDM in operation 605 includes the identifier of the PCF that was managing the PDN connection of the terminal in the EPS, the AMF can select this same PCF.

In operation 607, the AMF may perform an AM Policy Association establishment procedure for the UE-PCF used in the EPS (in this case, Old UE-PCF, New UE-PCF, and New AM-PCF may be the same PCF). .

In operation 608, the AMF may transmit a request message to SMF+PGW-C requesting creation of a PDU session. In operation 608, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). For example, a method of providing NR as the RAT Type to which the terminal is connected, or providing both E-UTRAN, the previous RAT Type that the terminal connected to through EPS, and NR, the current RAT Type to which the terminal is connected through 5GS. This may be included. In addition, in operation 608, the request message includes PCF Selection Assistance Information, an indicator indicating that the same PCF as the PCF used in the EPS connection of the terminal has been selected (i.e., same PCF selection indication), and/or operation 601 At least one of the identifiers (PCF ID which serving PDN Connection) of the PCF that previously managed the terminal's PDN Connection in the EPS may be included. At this time, the information included in the request message in operation 608 may include some or all of the information received by the AMF from the UDM in operation 605, or if the AMF did not receive information from the UDM in operation 605. Even so, it may be information provided by AMF to SMF+PGW-C. If the AMF does not receive information from the UDM in operation 605, the AMF or any other NF or any network entity determines that the corresponding Information can be conveyed.

In operation 609, the SMF+PGW-C may transmit a request message to the SM-PCF requesting that the SM Policy be modified for the PDN connection corresponding to the PDU session to be created. In operation 609, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). At this time, the information related to the RAT change may include some or all of the information received from the AMF in operation 608, or even if the information related to the RAT change is not received from the AMF, SMF+PGW-C May include information provided to SM-PCF. If the SMF+PGW-C does not receive information related to the RAT change from the AMF, the SMF+PGW-C or any other NF or arbitrary network entity determines and responds to the SM-PCF regarding the RAT change. information can be conveyed. In addition, in operation 609, the request message includes PCF Selection Assistance Information, an indicator indicating that the same PCF as the PCF used in the EPS connection of the terminal has been selected (i.e., same PCF selection indication), and/or operation 601 At least one of the identifiers (PCF ID which serving PDN Connection) of the PCF that previously managed the PDN Connection of the terminal in the EPS may be included. At this time, the information included in the request message in operation 609 may include some or all of the information received by SMF+PGW-C from AMF in operation 608, or SMF+PGW-C may receive information in operation 608. Even if information is not received from AMF, it may be information provided by SMF+PGW-C to SM-PCF. If the SMF+PGW-C does not receive information from the AMF in operation 608, SMF+PGW-C or another NF or any network entity determines the information included in the request message in operation 609. Corresponding information can be delivered to SM-PCF.

In operations 610a, 610b, and 610c, the SM-PCF may determine whether a new PCF can be used in 5GS or whether the PCF used in EPS should continue to be used. Parts or all of

operations

610a, 610b, and 610c may be performed sequentially/selectively or in parallel.

In operation 610a, the SM-PCF can determine whether the movement of the terminal is inter-system mobility. In other words, SM-PCF can determine that the terminal has moved from EPS to 5GS. Alternatively, SM-PCF can determine whether the UE's movement is inter-RAT mobility. In other words, it can be determined that the terminal has moved from EPS RAT (eg, E-UTRAN) to 5GS RAT (eg, NR).

In operation 610b, it can be determined whether a UE Policy Association established by the SM-PCF for the UE connected to the EPS exists.

In operation 610c, the SM-PCF can determine whether the same PCF as the PCF used in EPS can be used when the terminal moves from EPS to 5GS. This embodiment will be described assuming that the same PCF is used. However, the operation of this embodiment is not limited to the case where the same PCF is used.

Referring to FIG. 6B, in operation 611, the SM-PCF may transmit a request message requesting UE Policy modification to the old UE-PCF used in EPS (i.e., the same PCF). In operation 611, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). At this time, the information related to the RAT change may be transferring some or all of the information received by the SM-PCF from SMF+PGW-C in operation 609 to the old UE-PCF (i.e., the same PCF), or Even if the SM-PCF has not received information related to the RAT change from SMF+PGW-C, this may be information provided by the SM-PCF to the old UE-PCF (i.e., the same PCF). If the SM-PCF does not receive information related to the RAT change from SMF+PGW-C, the SM-PCF or any other NF or arbitrary network entity determines that the old UE-PCF (i.e. Corresponding information can be delivered to the same PCF). In addition, in operation 611, the request message includes PCF Selection Assistance Information, an indicator indicating that the same PCF as the PCF used in the EPS connection of the terminal has been selected (i.e., same PCF selection indication), and/or operation 601 At least one of the identifiers (PCF ID which serving PDN Connection) of the PCF that previously managed the PDN Connection of the terminal in the EPS may be included. At this time, the information included in the request message in operation 611 may include some or all of the information received by the SM-PCF from SMF+PGW-C in operation 609, and the SM-PCF sends the information to the old UE-PCF. It may be information transmitted, or it may be information provided by the SM-PCF to the old UE-PCF even if the SM-PCF did not receive information from the SMF+PGW-C in operation 609. If the SM-PCF does not receive information from the SMF+PGW-C in operation 609, the SM-PCF or any other NF or arbitrary network entity determines the information included in the request message in operation 611. Corresponding information can be delivered to the old UE-PCF (i.e., the same PCF). Additionally, in operation 611, the request message may also include an indicator (Indication of UDR-unsubscription not needed) informing the old UE-PCF used in EPS that the unsubscription procedure for UDR does not need to be performed. In the following description, it will be assumed that the old UE-PCF is the same PCF.

In operation 612, the old UE-PCF can obtain the latest UE Policy from the UDR through UE Policy Update, or provide the latest UE Policy to the UDR.

In operation 613, the old UE-PCF may respond to the UE Policy modification request in operation 611 by providing the latest UE Policy to the SM-PCF.

In operation 614, the SM-PCF may transmit a response message to the SM Policy modification request in operation 609 to SM+PGW-C, according to the determination result in operation 610c. In the description of this embodiment below, the operation when it is determined that the SM-PCF continues to use the PCF that was used in the EPS in operation 610c is described. In operation 614, the response message may include information related to UE Policy Association. The information related to the UE policy association includes (1) the identifier of the UE-PCF used in the EPS, (2) the identifier of the UE Policy Association established in the EPS, (3) the UE policy information stored by the SM-PCF, (4) ) At least one of the policy control request triggers stored by the SM-PCF may be included. In the case of the information in (3) and (4) above, the SM-PCF may be information obtained by immediately requesting the UE-PCF to provide it to SM+PGW-C. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 615, SMF+PGW-C may transmit a response message to the AMF for the PDU session creation request in operation 608. This response may include information related to UE Policy Association. Information related to UE policy association includes (1) identifier of UE-PCF used in EPS, (2) identifier of UE Policy Association established in EPS, (3) UE policy information stored by SM-PCF, (4) At least one of the policy control request triggers stored by the SM-PCF may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format. The information related to the UE policy association may include part or all of the information received by the SMF+PGW-C from the SM-PCF in operation 614, and the SMF+PGW-C has a direct association with the UE-PCF. In this case, it may include information received from the UE-PCF.

In operation 616, the MME may be deregistered for UDM+HSS.

Referring to FIG. 6C, in operation 617, the MME may request the SGW to delete the session.

In operation 618, if the AMF accepts the terminal's registration request for 5GS in operation 601, it may transmit an acceptance message to the terminal.

In operation 619, the AMF may transmit a request message requesting establishment or modification of a UE Policy Association to the newly selected UE-PCF. The request message in operation 619 may include at least one of (1) information related to UE Policy when provided by the UE to the AMF in operation 601, and (2) a UE Policy Association identifier. The information related to the UE Policy in (1) above may include an indicator indicating that the UE can transmit/receive the UE policy through the EPS entity, and this indicator may be included and provided in the UE Policy Container. The information related to the UE Policy in (1) above may include the information received by the AMF in operation 615, and this information is used by the UE-PCF in

operations

621 and 622 when determining the latest UE Policy for the UE. can be considered.

In operation 620, the new UE-PCF may request a subscription related to UE Policy data for UDR.

In operation 621, the new UE-PCF requests and obtains the latest UE Policy data from the UDR (Query), the UDR provides the latest UE Policy data to the UE-PCF (Notify), or the UE-PCF notifies the UE for the UE. After deciding on a policy, it can be provided to UDR.

In operation 622, the new UE-PCF may transmit a response message to the UE Policy Association establishment/modification request to the AMF. In operation 622, the response message may include information related to the UE Policy Association. Information related to UE policy association includes (1) identifier of the new UE-PCF, (2) identifier of the UE Policy Association established between the new UE-PCF and AMF, (3) UE policy information, and (4) policy control request trigger. At least one of may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 623, the AMF may provide terminal policy information to the terminal. This process can be performed through the UE Configuration Update procedure.

7A to 7C show UE Policy Association (UE Policy Association) during the process of a UE moving core network access from EPS to 5GS in a wireless communication system supporting interworking between EPS and 5GS according to an embodiment of the present disclosure. ) This is a drawing showing the procedure for managing. More specifically, Figures 7a to 7c show the procedure for managing the terminal policy association in 5GS by using the address of the PCF used in the EPS connection of the terminal when the terminal connects to 5GS. Another example is explained.

Referring to FIG. 7A, in operation 701, the terminal may transmit a registration request message to the AMF through the NG-RAN. In operation 701, the registration request message includes (1) registration type indicating Mobility Registration Update, (2) handover (or mobility) related information indicating that the terminal has moved from the EPS, and (3) stored by the terminal. At least one of the UE Policy Containers containing existing UE policy-related information may be included. The UE policy-related information included in the UE Policy Container may include an indicator (eg, URSP delivery in EPS Support indication) indicating that the UE can transmit/receive the UE policy through the EPS entity.

In operation 702a, the AMF may request information (Context) related to the terminal from the MME.

In operation 702b, the MME may provide information (Context) related to the terminal to the AMF in response to the request in operation 702a. The information related to the terminal includes the address of the UE-PCF (e.g. For example, FQDN) may be included.

In operation 703, the AMF may select UDM (or UDM+HSS).

In operation 704, the AMF may perform UECM registration with the UDM (or UDM+HSS) as an NF in charge of terminal connection and registration management.

In operation 705, the AMF may obtain subscription information (subscription data) of the terminal from UDM (or UDM+HSS).

In operation 706, the AMF may select a PCF for the AMF (in other words, a PCF in charge of AM Policy and UE Policy, PCF for AMF) (i.e., new AM-PCF/UE-PCF in FIG. 7A).

The operation 706 may include

operations

706a and 706b, and in operation 706a, the AMF may request the NRF to inform the NRF of a method to associate with the UE-PCF used in the EPS when selecting a PCF. At this time, AMF can use the address of the UE-PCF received from the MME in operation 702b. For example, the AMF provides the NRF with the first address of the UE-PCF (e.g., an FQDN that can access the UE-PCF using the N101 and/or N102 interface) received from the MME in operation 702b, so that the AMF A second address that can access the UE-PCF may be requested. The N101 and/or N102 interface may be referred to as a first interface.

In operation 706b, the NRF may provide the AMF with a way to associate with the UE-PCF used in the EPS. At this time, the NRF may provide the second address through which the AMF can access the UE-PCF. For example, the NRF allows the AMF to access the UE-PCF indicated by the first address of the UE-PCF provided by the AMF in operation 706a using the interface (e.g. N15) between the AMF and the UE-PCF. A second address (e.g., an FQDN that can access the UE-PCF using the N15 interface) may be provided to the AMF. The N15 may be referred to as a second interface. In

operations

706a and 706b, the operation of requesting from the NRF how the AMF can associate with the UE-PCF used in the EPS is not limited to the NRF, and includes UDM, Binding Support Function (BSF) (not shown), Alternatively, the request may be made to another NF or arbitrary network entity. The BSF manages registration/deregistration of a PCF as a PCF for a terminal or session, and provides a function of providing identification information of the PCF when another NF searches for a PCF for a terminal or session. For example, the AMF may request a method to associate with the UE-PCF used in the EPS from the BSF in operation 706a. At this time, the AMF includes at least one of the terminal's address (e.g., UE IP address and/or UE MAC address), terminal identifier (e.g., SUPI and/or GPSI (Generic Public Subscription Identifier), DNN, and S-NSSAI. By providing one to the BSF, the AMF may request an address that can access the UE-PCF and/or an identifier of the UE-PCF. The BSF may use the Nbsf Management discovery request message. Provides AMF with an address that can access the UE-PCF (e.g., PCF address) and/or an identifier (e.g., PCF instance ID, and/or PCF Set ID) of the UE-PCF. BSF can use the Nbsf Management discovery response message.

In operation 707, the AMF uses the second address of the UE-PCF provided by the NRF in operation 706b to connect the UE-PCF used in the EPS (in this case, Old UE-PCF, New UE-PCF, and New AM-PCF) can be the same PCF), the AM Policy Association establishment procedure can be performed. AMF can store the PCF ID of the UE-PCF.

In operation 708, the AMF may transmit a request message to SMF+PGW-C requesting creation of a PDU session. In operation 708, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). For example, a method of providing NR as the RAT Type to which the terminal is connected, or providing both E-UTRAN, the previous RAT Type that the terminal connected to through EPS, and NR, the current RAT Type to which the terminal is connected through 5GS. This may be included. Additionally, in operation 708, the request message may include the identifier (PCF ID which serving PDN Connection) of the PCF that was managing the PDN Connection of the terminal in the EPS before operation 701. The identifier of the PCF that was managing the PDN connection of the terminal in the EPS may be the PCF ID stored by the AMF in operation 707 above.

In operation 709, the SMF+PGW-C may transmit a request message to the SM-PCF requesting that the SM Policy be modified for the PDN connection corresponding to the PDU session to be created. In operation 709, the request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). At this time, the information related to the RAT change may include some or all of the information received from the AMF in operation 708, or even if the information related to the RAT change is not received from the AMF, SMF+PGW-C May include information provided to SM-PCF. If the SMF+PGW-C does not receive information related to the RAT change from the AMF, the SMF+PGW-C or any other NF or arbitrary network entity determines and responds to the SM-PCF regarding the RAT change. information can be conveyed. Additionally, in operation 709, the request message may include the identifier (PCF ID which serving PDN Connection) of the PCF that was managing the PDN Connection of the terminal in the EPS before operation 701. The identifier of the PCF that was managing the PDN connection of the terminal in the EPS may be the PCF ID stored by the AMF in operation 707 above. At this time, the information included in the request message in operation 709 may include some or all of the information received by SMF+PGW-C from AMF in operation 708, or the information received by SMF+PGW-C in operation 708. Even if information is not received from AMF, this may be information provided by SMF+PGW-C to SM-PCF. If the SMF+PGW-C does not receive information from the AMF in operation 708, SMF+PGW-C or another NF or any network entity determines the information included in the request message in operation 709. Corresponding information can be delivered to SM-PCF.

In operations 710a, 710b, and 710c, the SM-PCF may determine whether a new PCF can be used in 5GS or whether the PCF used in EPS should continue to be used.

Operations

710a, 710b, and 710c may be performed in whole or in part sequentially/selectively, or in parallel.

In operation 710a, the SM-PCF can determine whether the movement of the terminal is inter-system mobility. In other words, SM-PCF can determine that the terminal has moved from EPS to 5GS. Alternatively, SM-PCF can determine whether the UE's movement is inter-RAT mobility. In other words, it can be determined that the terminal has moved from EPS RAT (eg, E-UTRAN) to 5GS RAT (eg, NR).

In operation 710b, it can be determined whether a UE Policy Association established by the SM-PCF for the UE connected to the EPS exists.

In operation 710c, when the terminal moves from EPS to 5GS, it can be determined whether the same PCF as the PCF used in EPS can be used. This embodiment will be described assuming that the same PCF is used.

In operation 711, the SM-PCF may transmit a request message requesting UE Policy modification to the old UE-PCF used in EPS. The operation 713 request message may include information that can notify that the Radio Access Technology (RAT) type to which the terminal has accessed has changed (i.e., information related to RAT change). At this time, the information related to the RAT change may be transmitting some or all of the information received by the SM-PCF from the SMF+PGW-C in operation 709 to the old UE-PCF, or the SM-PCF may transfer some or all of the information received from the SMF+PGW-C in operation 709 to the old UE-PCF. Even if information related to the RAT change is not received from the PGW-C, the SM-PCF may provide it to the old UE-PCF (i.e., the same PCF). If the SM-PCF does not receive information related to the RAT change from SMF+PGW-C, the SM-PCF or any other NF or arbitrary network entity determines that the old UE-PCF is responsible for the RAT change. information can be conveyed. Also, above. At this time, the information included in the request message in operation 711 may include some or all of the information received by the SM-PCF from SMF+PGW-C in operation 709, and the SM-PCF sends the message to the old UE-PCF. It may be information transmitted, or it may be information provided by the SM-PCF to the old UE-PCF even if the SM-PCF did not receive information from the SMF+PGW-C in operation 709. If the SM-PCF does not receive information from the SMF+PGW-C in operation 709, the SM-PCF or another NF or any network entity determines the information included in the request message in operation 713. Corresponding information can be delivered to the old UE-PCF. Additionally, in operation 711, the request message may include an indicator (Indication of UDR-unsubscription not needed) informing the old UE-PCF used in EPS that the unsubscription procedure for UDR does not need to be performed. In operation 711, the request message may include an indicator indicating that the same PCF as the PCF used in the terminal's EPS connection has been selected (i.e., same PCF selection indication). In the following description, it will be assumed that the old UE-PCF is the same PCF.

In operation 712, the old UE-PCF can obtain the latest UE Policy from the UDR through UE Policy Update, or provide the latest UE Policy to the UDR.

In operation 713, the old UE-PCF may respond to the UE Policy modification request in operation 711 by providing the latest UE Policy to the SM-PCF.

In operation 714, the SM-PCF may transmit a response message to the SM Policy modification request in operation 709 to SM+PGW-C, according to the determination result in operation 710c. The response message may include information related to UE Policy Association. The information related to the UE policy association includes (1) the identifier of the UE-PCF used in the EPS, (2) the identifier of the UE Policy Association established in the EPS, (3) the UE policy information stored by the SM-PCF, (4) ) At least one of the policy control request triggers stored by the SM-PCF may be included. In the case of the information in (3) and (4) above, the SM-PCF may be information obtained by immediately requesting the UE-PCF to provide it to SM+PGW-C. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 715, SMF+PGW-C may transmit a response message to the AMF for the PDU session creation request in operation 708. This response may include information related to UE Policy Association. Information related to UE policy association includes (1) identifier of UE-PCF used in EPS, (2) identifier of UE Policy Association established in EPS, (3) UE policy information stored by SM-PCF, (4) At least one of the policy control request triggers stored by the SM-PCF may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format. The information related to the UE policy association may include part or all of the information received by the SMF+PGW-C from the SM-PCF in operation 714, and the SMF+PGW-C has a direct association with the UE-PCF. In this case, it may include information received from the UE-PCF.

Referring to FIG. 7C, in operation 716, the MME's registration for UDM+HSS may be released.

In operation 717, the MME may request the SGW to delete the session.

In operation 718, if the AMF accepts the terminal's registration request for 5GS in operation 701, it may transmit an acceptance message to the terminal.

In operation 719, the AMF may transmit a request message requesting establishment or modification of a UE Policy Association to the newly selected UE-PCF. The request message in operation 719 may include at least one of (1) information related to UE Policy when provided by the UE to the AMF in operation 701, and (2) a UE Policy Association identifier. The information related to the UE Policy in (1) above may include an indicator indicating that the UE can transmit/receive the UE policy through the EPS entity, and this indicator may be included and provided in the UE Policy Container. The information related to the UE Policy in (1) may include the information received by the AMF in operation 715, and this information is used by the UE-PCF in steps 21 and 22 when determining the latest UE Policy for the UE. can be considered.

In operation 720, the new UE-PCF may request a subscription related to UE Policy data for UDR.

In operation 721, the new UE-PCF requests and obtains the latest UE Policy data from the UDR (Query), the UDR provides the latest UE Policy data to the UE-PCF (Notify), or the UE-PCF notifies the UE for the UE. After deciding on a policy, it can be provided to UDR.

In operation 722, the new UE-PCF may transmit a response message to the UE Policy Association establishment/modification request to the AMF. In operation 722, the response message may include information related to the UE Policy Association. Information related to UE policy association includes (1) identifier of the new UE-PCF, (2) identifier of the UE Policy Association established between the new UE-PCF and AMF, (3) UE policy information, and (4) policy control request trigger. At least one of may be included. The terminal policy information in (3) above may include a PSI (Policy Section Identifier) list and/or terminal policy data, which may be provided in the UE Policy Container format.

In operation 723, the AMF may provide terminal policy information to the terminal. This process can be performed through the UE Configuration Update procedure.

The network entity in FIG. 8 may be one of the network entities described in the embodiments of FIGS. 1 to 7 .

A network entity according to an embodiment of the present disclosure may include a processor 801 that controls the overall operation of the network entity, a transceiver 803 including a transmitter and a receiver, and a memory 805. Of course, it is not limited to the above example, and the network entity may include more or fewer configurations than the configuration shown in FIG. 8.

According to an embodiment of the present disclosure, the transceiver 803 may transmit and receive signals with at least one of other network entities or a terminal. Signals being transmitted and received may include at least one of control information and data. When the network entity in FIG. 8 is a core network entity (NF), signals transmitted and received between the network entity and the terminal may be transmitted and received via the RAN.

According to an embodiment of the present disclosure, the processor 801 may generally control the operation of the network entity to perform an operation according to one or a combination of two or more of the embodiments of FIGS. 1 to 7 described above. there is. Meanwhile, the processor 801, transceiver 803, and memory 805 do not necessarily have to be implemented as separate modules, and of course can be implemented as a single component in the form of a single chip. And the processor 801 may be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor. The transceiver 803 may include at least one communication interface for transmitting and receiving signals wired/wireless with other network entities.

According to an embodiment of the present disclosure, the memory 805 may store data such as basic programs, applications, and setting information for the operation of the corresponding network entity. Additionally, the memory 805 provides stored data upon request from the processor 801. The memory 805 may be composed of a storage medium such as ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. Additionally, there may be multiple memories 805. Additionally, the processor 801 may perform at least one of the above-described embodiments based on a program for performing an operation according to at least one of the above-described embodiments of the present disclosure stored in the memory 805.

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

When implemented as software, a computer-readable storage medium that stores one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured to be executable by one or more processors in an electronic device (configured for execution). 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 invention.

These programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM: Compact Disc-ROM), Digital Versatile Discs (DVDs), or other types of It can be stored in an optical storage device or magnetic cassette. Alternatively, it may be stored in a memory consisting of a combination of some or all of these. Additionally, multiple configuration memories may be included.

In addition, the program may be operated through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or a combination thereof. It may be stored on an attachable storage device that is accessible. This storage device can be connected to a device performing an embodiment of the present invention through an external port. Additionally, a separate storage device on a communication network may be connected to the device performing an embodiment of the present invention.

Meanwhile, the embodiments disclosed in the specification and drawings described above are only provided as specific examples to easily explain the contents of the present invention and aid understanding, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed as including all changes or modified forms derived based on the technical idea of the present invention in addition to the embodiments disclosed herein. Additionally, each of the above embodiments can be operated in combination with each other as needed, as long as there is no technical contradiction.

Claims

In a method performed in an access and mobility management function (AMF) in a wireless communication system supporting interworking between a first network and a second network,

Receiving a terminal registration request message from a terminal moving from the first network to the second network;

Based on the first address information related to the first interface for accessing the first PCF (policy control function) used in the first network, second address information related to the second interface for accessing the first PCF is generated. the process of acquiring;

Performing a policy association establishment procedure for the first PCF based on the second address information;

Transmitting a request message containing information related to a change in radio access technology (RAT) of the terminal to a first network entity that manages a protocol data unit (PDU) session for the terminal in the second network; and

A method comprising receiving a response message including terminal policy association-related information from the first network entity.
According to claim 1,

A method wherein the first PCF and the second PCF are the same PCF.
According to claim 1,

A method in which the first address information and the second address information are expressed in a Fully Qualified Domain Name (FQDN) format.
According to claim 1,

The first network is EPS, the second network is 5GS,

A method in which the terminal moves network access from the EPS to the 5GS.
In access and mobility management function (AMF) in a wireless communication system supporting interworking between a first network and a second network,

transceiver; and

Receiving a terminal registration request message from a terminal moving from the first network to the second network through the transceiver,

Based on the first address information related to the first interface for accessing the first PCF (policy control function) used in the first network, second address information related to the second interface for accessing the first PCF is generated. acquire,

Based on the second address information, perform a policy association establishment procedure for the first PCF,

Transmit, through the transceiver, a request message containing information related to a radio access technology (RAT) change of the terminal to a first network entity that manages a protocol data unit (PDU) session for the terminal in the second network. And

AMF comprising a processor configured to receive a response message including terminal policy association-related information from the first network entity through the transceiver.
According to claim 5,

AMF wherein the first PCF and the second PCF are the same PCF.
According to claim 5,

AMF in which the first address information and the second address information are expressed in FQDN (Fully Qualified Domain Name) format.
According to claim 5,

The first network is EPS, the second network is 5GS,

The terminal is an AMF in which network access is moved from the EPS to the 5GS.
In a method performed in a session management-policy control function (SM-PCF) in a wireless communication system supporting interworking between a first network and a second network,

For modifying a session management policy, including information related to a change in radio access technology (RAT) of the terminal, from a first network entity that has received a PDU session establishment request from a terminal moving from the first network to the second network. , the process of receiving a request message;

A process of determining whether a policy control function (PCF) used in the first network for the terminal is used in the second network; and

A method comprising transmitting a response message including terminal policy association-related information to the first network entity based on the determination.
According to clause 9,

The terminal policy association information includes the identifier of the PCF used in the first network, the identifier of the terminal policy association established in the first network, the terminal policy information stored by the SM-PCF, and the SM-PCF A method that contains at least one of the policy control request triggers that was being stored.
According to clause 9,

The first network is EPS, the second network is 5GS,

A method in which the terminal moves network access from the EPS to the 5GS.
In a session management-policy control function (SM-PCF) in a wireless communication system supporting interworking between a first network and a second network,

transceiver; and

A session containing information related to a change in radio access technology (RAT) of the terminal from a first network entity that has received a PDU session establishment request from a terminal moving from the first network to the second network through the transceiver. Receive request messages to modify management policies,

Determine whether a policy control function (PCF) used in the first network for the terminal is used in the second network,

SM-PCF comprising a processor configured to transmit a response message including terminal policy association-related information to the first network entity through the transceiver based on the determination.
According to claim 12,

The terminal policy association information includes the identifier of the PCF used in the first network, the identifier of the terminal policy association established in the first network, the terminal policy information stored by the SM-PCF, and the SM-PCF An SM-PCF that contains at least one of the policy control request triggers that was stored by .
According to claim 12,

The first network is EPS, the second network is 5GS,

The terminal is an SM-PCF whose network connection is moved from the EPS to the 5GS.