Method for resolving incongruity between terminal route selection policy and session information

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. An operation method of a user equipment (UE) based on a UE route selection policy (URSP), according to one embodiment of the present disclosure, may comprise the operations of: transmitting, to a mobility management entity (MME), a first message (attach request) including at least one of a first indicator (URSI) indicating support for reporting URSP-associated session information and a second indicator (UERSI) indicating support for a URSP enforcement report; receiving, from the MME, a second message (EPS bearer context request) including a URSP rule; and transmitting, to the MME, a third message (PDN connectivity request) including at least one of the URSP-associated session information and the URSP enforcement report.

Description

How to resolve discrepancies between terminal path selection policy and session information

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method for confirming compliance with a terminal routing selection policy (URSP) of a terminal in a cellular wireless communication system (5G System).

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

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

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

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

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

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

[0008] Meanwhile, 3GPP, which is in charge of cellular mobile communication standards, is naming a new core network structure 5G Core (5GC) and proceeding with standardization to promote evolution from the existing 4G LTE system to a 5G system.

[0009] 5GC supports the following differentiated features compared to the Evolved Packet Core (EPC), the network core for existing 4G.

[0010] First, 5GC introduces the Network Slice feature. As a requirement of 5G, 5GC must support a variety of terminal types and services, such as enhanced Mobile Broadband (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC). These terminals and services each have different requirements for the core network. For example, eMBB services require high data rates, while URLLC services require high reliability and low latency. Network Slice is a proposed technology to meet these diverse service requirements.

[0011] Network slicing virtualizes a single physical network to create multiple logical networks. Each Network Slice Instance (NSI) can have distinct characteristics. Therefore, each NSI can have a network function (NF) tailored to its specific characteristics, enabling it to meet diverse service requirements. By assigning an NSI tailored to the service requirements of each terminal, various 5G services can be efficiently supported.

[0012] Second, 5GC can easily support the network virtualization paradigm by separating mobility management and session management functions. In existing 4G LTE, all terminals could receive network services through signaling exchanges with a single core device called the Mobility Management Entity (MME), which was responsible for registration, authentication, mobility management, and session management. However, in 5G, the number of terminals will explode, and the mobility and traffic / session characteristics that must be supported will become more specialized depending on the terminal type. Therefore, supporting all functions with a single device like the MME will inevitably reduce scalability by adding entities for each required function. Therefore, various functions are being developed based on a structure that separates mobility management and session management functions to improve scalability in terms of functional / implementation complexity and signaling load of the core device responsible for the control plane.

[0013] When a 5GC-EPC Interworking terminal in a network accesses the EPC and creates a PDN (packet data network) connection according to the URSP (UE route selection policy) rule, the terminal cannot transmit S-NSSAI (single-network slice selection assistance information) information matching the URSP to the network, and when creating a PDN connection, the PGW-C (PDN gateway control plane function) / SMF (session management function) can select the associated S-NSSAI based on the APN (access point name) transmitted by the terminal.

[0014] Afterwards, when the terminal moves to a 5GC network that supports network slicing, the PDN connection created with the PGW-C / SMF provides seamless mobility as a PDU (protocol data unit) session of the 5GC network, and the terminal uses the network slice for the S-NSSAI associated when the PDN was created in the EPC. At this time, the associated S-NSSAI may be a different value from the S-NSSAI value specified in the URSP rule delivered to the terminal.

[0015] In this disclosure, a method for resolving a mismatch between an S-NSSAI value specified by a URSP rule and an S-NSSAI assigned to a terminal is proposed.

[0016] In a wireless communication system according to one embodiment, a method for operating a user equipment (UE) based on a UE route selection policy (URSP) may include: transmitting a first message (attach request) to a mobility management entity (MME) including at least one of a first indicator (URSI) indicating support for reporting on URSP-associated session information and a second indicator (UERSI) indicating support for a URSP enforcement report; receiving a second message (EPS bearer context request) including a URSP rule from the MME; and transmitting a third message (PDN connectivity request) including at least one of the URSP-associated session information and the URSP enforcement report to the MME.

[0017] In a wireless communication system according to one embodiment, a method of operating a network entity (PGW-C / SMF) may include receiving, from a serving gateway (S-GW), a first message (create session request) including at least one of a first indicator (URSI) indicating support for reporting on UE route selection policy (URSP)-associated session information and a second indicator (UERSI) indicating support for a URSP enforcement report; receiving, from the S-GW, a second message (create session request) including at least one of the URSP-associated session information and the URSP enforcement report; and transmitting, to the S-GW, a third message (create session response) including single-network slice selection assistance information (S-NSSAI).

[0018] In a wireless communication system according to one embodiment, a user equipment (UE) based on a UE route selection policy (URSP) includes a transceiver; and a control unit. The control unit may control to transmit a first message (attach request) including at least one of a first indicator (URSI) indicating support for reporting on URSP-associated session information and a second indicator (UERSI) indicating support for a URSP enforcement report to a mobility management entity (MME), receive a second message (EPS bearer context request) including a URSP rule from the MME, and transmit a third message (PDN connectivity request) including at least one of the URSP-associated session information and the URSP enforcement report to the MME.

[0019] In a wireless communication system according to one embodiment, a network entity (PGW-C / SMF) includes a transceiver; and a control unit. The control unit can control to receive, from a serving gateway (S-GW), a first message (create session request) including at least one of a first indicator (URSI) indicating support for reporting on UE route selection policy (URSP)-associated session information and a second indicator (UERSI) indicating support for a URSP enforcement report, receive, from the S-GW, a second message (create session request) including at least one of the URSP-associated session information and the URSP enforcement report, and transmit, to the S-GW, a third message (create session response) including single-network slice selection assistance information (S-NSSAI).

[0020] A method and device according to one embodiment of the present disclosure can resolve a mismatch between slice selection according to a URSP policy and slices allocated to a terminal in a network in a terminal supporting 5GC-EPC Interworking.

[0021] Figure 1 is a diagram showing the 5G system network structure.

[0022] Figure 2 is a diagram illustrating the concept of a UE Route Selection Policy (hereinafter referred to as URSP).

[0023] FIG. 3 is a diagram illustrating a 5GC-EPC scenario according to one embodiment of the present disclosure.

[0024] FIG. 4a, FIG. 4b, and FIG. 4c are diagrams illustrating a procedure for receiving URSP association information of a terminal and recovering slice mismatch in an EPC network according to one embodiment of the present disclosure.

[0025] FIGS. 5A, 5B, and 5C are diagrams illustrating a procedure for receiving URSP association information of a terminal and recovering slice mismatch after moving to a 5GC network according to one embodiment of the present disclosure.

[0026] FIG. 6 is a block diagram showing the structure of a terminal according to one embodiment of the present disclosure.

[0027] FIG. 7 is a block diagram showing the structure of a network entity according to one embodiment of the present disclosure.

[0028] FIG. 8 is a flowchart showing the operation of a terminal according to one embodiment of the present disclosure.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, when describing the present invention, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, such detailed description will be omitted. In addition, the terms described below are terms defined in consideration of their functions in the present invention, and these may vary depending on the intention or custom of the user or operator. Therefore, their definitions should be made based on the contents throughout this specification. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically illustrated. Furthermore, the size of each component does not entirely reflect the actual size. Identical or corresponding components in each drawing are assigned the same reference numerals. The advantages and features of the technical ideas according to the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, and these embodiments are provided only to make the present disclosure complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification. In addition, when describing the present disclosure, if it is determined that a specific description of a related function or configuration may unnecessarily obscure the gist of the technical idea according to the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of the functions in the present disclosure, and this may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout the present specification.

[0030] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of an eNode B, a Node B, a BS (Base Station), a RAN (Radio Access Network), an AN (Access Network), a RAN node, a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present invention, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although the embodiments of the present disclosure are described below using an LTE or LTE-A system as an example, the embodiments of the present disclosure may also be applied to other communication systems having a similar technical background or channel type. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in a system to which the embodiments of the present disclosure can be applied, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the embodiments of the present disclosure may be applied to other communication systems with some modifications within a scope that does not significantly deviate from the scope of the present invention, as judged by a person having skilled technical knowledge. In this case, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions.

[0031] These computer program instructions may be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, so that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for performing the functions described in the flowchart block(s). These computer program instructions may also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing apparatus to implement functions in a particular manner, so that the instructions stored in the computer-available or computer-readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the flowchart block(s). The computer program instructions may also be installed on a computer or other programmable data processing apparatus, so that a series of operational steps are performed on the computer or other programmable data processing apparatus to create a computer-implemented process, so that the instructions executing on the computer or other programmable data processing apparatus can provide steps for performing the functions described in the flowchart block(s).

[0032] Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function. In this case, the term '~unit' used in the embodiments of the present disclosure means software or a hardware component such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), and the '~unit' may perform certain roles. However, the '~unit' is not limited to software or hardware. The '~unit' may be configured to be on an addressable storage medium and may be configured to execute one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to reproduce one or more CPUs within a device or a secure multimedia card. Also, in an embodiment, the '~ unit' may include one or more processors.

[0033] Figure 1 is a diagram showing the 5G system network structure.

[0034] FIG. 1 illustrates the network structure and interface of a 5G system (100) according to one embodiment of the present disclosure.

[0035] A network entity included in the network structure of the 5G system (100) of FIG. 1 may include a network function (NF) depending on the system implementation.

[0036] Referring to FIG. 1, the network structure of a 5G system (100) may include various network entities. For example, the 5G system (100) may include an authentication server function (AUSF) (108), an access and mobility management function ((core) access and mobility management function (AMF) (103), a session management function (SMF) (105), a policy control function (PCF) (106), an application function (AF) (107), a unified data management (UDM) (109), a data network (DN) (110), a network exposure function (NEF) (113), a network slicing selection function (NSSF) (114), a network repository function (NRF) (115), an edge application service domain repository (EDR, not shown), an edge application server (EAS, not shown), and an EAS discovery function (EAS discovery). function: EASDF, not shown), user plane function (UPF) (104), (radio) access network ((R)AN) (102), and terminal, i.e., user equipment (UE) (101).

[0037] Each NF of the 5G system (100) supports the following functions.

[0038] AUSF (108) processes and stores data for authentication of UE (101).

[0039] AMF (103) provides functions for access and mobility management per UE, and one UE can be connected to one AMF (103) by default. AMF (103) provides CN inter-node signaling for mobility between 3GPP access networks, termination of radio access network (RAN) CP interface (i.e., N2 interface), termination of non-access stratum (NAS) signaling (N1), NAS signaling security (NAS ciphering and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE reachability (including control and performance of paging retransmission), mobility management control (subscription and policy), intra-system mobility and inter-system mobility support, support for network slicing, SMF selection, lawful intercept (for AMF events and interfaces to LI systems), provision of forwarding of session management (SM) messages between UE and SMF, transparent proxy for SM message routing, access authentication, access authorization including roaming authorization check. It may support functions such as providing transmission of SMS messages between UE and SMSF, security anchor function (SAF), and / or security context management (SCM). Some or all of the functions of AMF (103) may be supported within a single instance of AMF.

[0040] DN (110) refers to, for example, an operator service, Internet access, or a third-party service. DN (110) can transmit a downlink protocol data unit (PDU) to UPF (104) or receive a PDU transmitted from UE (101) from UPF (104).

[0041] PCF (106) may receive information about packet flow from an application server and provide a function to determine policies such as mobility management and session management. PCF (106) may support functions such as supporting a unified policy framework for controlling network operations, providing policy rules so that control plane functions (e.g., AMF, SMF, etc.) can enforce the policy rules, and implementing a front end for accessing related subscription information for policy determination within a user data repository (UDR).

[0042] SMF (105) provides a session management function, and when a UE has multiple sessions, each session can be managed by a different SMF. The SMF (105) may support functions such as session management (e.g., session establishment, modification, and termination, including tunnel maintenance between UPF (104) and (R)AN (102) nodes), UE IP address allocation and management (optionally including authentication), selection and control of UP functions, traffic steering setup to route traffic from UPF (104) to appropriate destinations, termination of the interface to policy control functions, enforcement of the control portion of policies and quality of service (QoS), lawful intercept (for SM events and interfaces to LI systems), termination of the SM portion of NAS messages, downlink data notification, initiation of AN specific SM information (forwarded to (R)AN (102) via N2 via AMF (103)), determination of the SSC mode of the session, and / or roaming functions. Some or all of the functions of SMF (105) may be supported within a single instance of an SMF.

[0043] The UDM (109) can store user subscription data, policy data, etc. The UDM (109) can include two parts, namely, an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

[0044] The FE may include a UDM FE responsible for location management, subscription management, and credential processing, and a PCF (106) responsible for policy control. The UDR may store data required for functions provided by the UDM-FE and policy profiles required by the PCF (106). Data stored in the UDR may include user subscription data and policy data, including subscription identifiers, security credentials, access and mobility-related subscription data, and session-related subscription data. The UDM-FE may access subscription information stored in the UDR and support functions such as authentication credential processing, user identification handling, access authentication, registration / mobility management, subscription management, and / or SMS management.

[0045] UPF (104) can transmit a downlink PDU received from DN (110) to UE (101) via (R)AN (102), and can transmit an uplink PDU received from UE (101) via (R)AN (102) to DN (110). The UPF (104) may support functions such as an anchor point for intra / inter RAT mobility, an external PDU session point for interconnection to the Data Network, a user plane portion of packet routing and forwarding, packet inspection and policy rule enforcement, an uplink classifier to support lawful intercept, traffic usage reporting, routing of traffic flows to the Data Network, a branching point to support multi-homed PDU sessions, QoS handling for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement), uplink traffic validation (service data flow (SDF) to QoS flow mapping), transport level packet marking in uplink and downlink, downlink packet buffering and downlink data notification triggering. Some or all of the functions of UPF (104) may be supported within a single instance of a UPF.

[0046] The AF (107) can interact with the 3GPP core network to provide services (e.g., support functions such as application impact on traffic routing, access to network capability exposure, and interaction with policy frameworks for policy control).

[0047] (R)AN(102) is a general term for a new radio access network that supports both evolved E-UTRA, an evolved version of 4G radio access technology, and new radio (NR) (e.g., gNB).

[0048] The gNB provides functions for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to the UE in uplink / downlink (i.e., scheduling), IP (internet protocol) header compression, encryption and integrity protection of user data streams, selection of an AMF upon attachment of the UE if routing to the AMF is not determined from the information provided to the UE, routing of user plane data to UPF(s), routing of control plane information to the AMF, connection setup and teardown, scheduling and transmission of paging messages (originating from the AMF), scheduling and transmission of system broadcast information (originating from the AMF or operating and maintenance (O&M)), measurement and measurement reporting setup for mobility and scheduling, transport level packet marking in uplink, session management, support for network slicing, and QoS flows. It may support features such as mapping to management and data radio bearers, support for UEs in inactive mode, distribution of NAS messages, NAS node selection, radio access network sharing, dual connectivity, and / or tight interworking between NR and E-UTRA.

[0049] UE (101) refers to a user device. The user device may be referred to by terms such as terminal, mobile equipment (ME), or mobile station (MS). Furthermore, the user device may be a portable device such as a laptop, mobile phone, personal digital assistant (PDA), smartphone, or multimedia device, or may be a non-portable device such as a personal computer (PC) or vehicle-mounted device.

[0050] The NEF (111) may provide a means to securely expose services and capabilities provided by 3GPP network functions, for example, for third parties, internal exposure / re-exposure, application functions, and edge computing. The NEF (111) may receive information from other NF (s) (based on the exposed capability (s) of other NF (s)). The NEF (111) may store the received information as structured data using a standardized interface to a data storage network function. The stored information may be re-exposed to other NF (s) and AF (s) by the NEF (111) and used for other purposes, such as analysis.

[0051] NSSF (114) can select a set of network slice instances serving UE (101). In addition, NSSF (114) can determine the allowed NSSAI (network slice selection assistance information) and, if necessary, perform mapping to subscribed single-network slice selection assistance information (S-NSSAI). In addition, NSSF (114) can determine the configured NSSAI and, if necessary, perform mapping to subscribed S-NSSAI. In addition, NSSF (114) can determine the set of AMFs used to serve UE or, depending on the configuration, can inquire NRF (115) to determine a list of candidate AMFs.

[0052] NRF (115) can support a service discovery function. NRF (115) can receive NF discovery requests from NF instances and provide information about discovered NF instances to the NF instances. In addition, NRF (115) can maintain available NF instances and the services they support.

[0053] A URSP rule may be composed of traffic descriptor information (TD) that can identify a terminal application or traffic generated by a terminal application, as described in Table 1, and a route selection component (RSC) that determines which PDU session to associate the terminal application or terminal application traffic with when the identified traffic descriptor is detected.

[0054] [Table 1] URSP Rules

[0055]

[0056] A traffic descriptor contains information about the terminal application or features for detection in the application and may include the following elements:

[0057] ■ Application descriptor: Information that can designate the terminal's application, including OSID and APPID.

[0058] ■ IP Descriptor: Displays the IP address that represents the destination address of the IP packet transmitted by the terminal. It can include IP 3-tuple, i.e., IP destination address, port number, and protocol.

[0059] ■ Non-IP descriptor: This is information that can specify the recipient of Non-IP data.

[0060] ■ Domain Descriptor: Expresses the destination address of the server to which the terminal connects in FQDN (Fully Qualified Domain Name) format.

[0061] ■ Connection Capability (CC): This corresponds to the type information that can specify the characteristics of the connected traffic, and can have values ​​such as IMS (IP Multimedia Subsystem), MMS (Multimedia Messaging Service), and Internet.

[0062] ■ DNN: This is the name of the data network.

[0063] The Route Selection Component (RSC) includes the following elements that can specify the properties of a PDU session so that the application or application traffic detected by the traffic descriptor corresponds to a specific PDU session, as described in Table 1.

[0064] ■ DNN (Data Network Name): This is the data network name. When a terminal connects to the EPC network, it can be used in the same way as the APN (Access Point Name).

[0065] ■ S-NSSAI: Information that can specify a network slice.

[0066] ■ PDU Session Type: This is an element that can specify the type of PDU-Session, which can be IPv4, IPv6, or IPv4v6, or Ethernet, or Non-IP.

[0067] ■ SSC Mode: This is an element that indicates the continuity of sessions and services and can have values ​​of SSC Mode 1, 2, and 3.

[0068] ■ Access-Type: This element indicates whether the PDU session is connected via 3GPP access or via Non-3GPP access.

[0069] Multiple URSP rules are divided into Policy Sections within the UE Policy Container, and can be divided and included in multiple Policy Sections so as not to exceed the maximum allowable transmission size of the NAS layer. A single URSP rule cannot be divided and included in two Policy Sections, and a single URSP rule must be included in a single Policy Section.

[0070] USRP rules have priority on a rule-by-rule basis.

[0071] The terminal can receive URSP rules from the NAS layer. The terminal can then detect terminal applications or terminal application traffic.

[0072] Here are some ways to detect terminal applications:

[0073] ■ Terminal applications can request specific networks through the API (Application Programming Interface) provided by the terminal operating system. The API provided by the terminal operating system can include direct information corresponding to the traffic descriptor received from the terminal modem's NAS, or information that can be mapped to the traffic descriptor, and can be transmitted through the API.

[0074] ■ Detection of terminal applications can be indirectly detected by the terminal operating system. For example, in the Android operating system of a terminal, when a terminal application is installed, the package manager that manages it can determine whether it has been installed, and the status of the app can be determined by detecting the user's actions. Depending on the status of the application managed within the operating system, the network connection of the app can be indirectly detected by detecting a change in status, such as an event in which the application occupies the user's screen (a transition event to foreground activity).

[0075] ■ The terminal operating system can detect the terminal application or traffic generated by the terminal application even when the terminal application calls an API that transmits packets through the terminal operating system.

[0076] ■ When a terminal application attempts to access a service running on the Internet or edge computing by providing an FQDN, the terminal operating system can detect the FQDN provided by the terminal application.

[0077] When the terminal's operating system detects such an application or traffic generated by an application in the URSP Handler, the URSP Handler checks the URSP rules received from the NAS to determine which URSP rule the detected application corresponds to.

[0078] When the URSP Handler finds a TD that matches the URSP rule, it checks whether a PDU session matching the RSC corresponding to the TD is currently created. If a PDU session with an RSC that matches the URSP rule already exists, the URSP Handler binds the corresponding terminal application to the corresponding PDU session. In the future, traffic generated from the bound application will be forwarded using the bound PDU session.

[0079] If there is no PDU session containing the RSC associated with the traffic descriptor found by the URSP Handler, the URSP Handler may initiate a PDU session creation procedure to create the corresponding PDU session. When creating a PDU session, the terminal may initiate the creation of the PDU session by including the PDU session parameters corresponding to the RSC of the URSP rule.

[0080] In the present disclosure, when a URSP handler detects an application or traffic of an application, and a corresponding URSP rule exists, but a PDU session with a corresponding RSC has not been created, the URSP handler can initiate the creation of a new PDU session and can transmit a session creation request message together with a PDU session parameter corresponding to the RSC included in the URSP rule, and content that can designate the discovered application.

[0081] For consistency in explanation, in this disclosure, information that can indicate a discovered application is referred to as URSP Enforcement report information. URSP Enforcement report information can also utilize traffic descriptor values ​​(e.g., application descriptor, DNN, IP address, FQDN, connection capability, etc.). Representative traffic descriptor values ​​and associated path selection elements such as DNN, APN, and S-NSSAI values ​​can also be included.

[0082] When a terminal receives a Connection Capability transmitted with a URSP rule, if a detected application corresponds to the Connection Capability, it can perform an action of reporting the Connection Capability when requesting or modifying a PDU session.

[0083] Figure 2 is a diagram illustrating the concept of a UE Route Selection Policy (hereinafter referred to as URSP).

[0084] Referring to FIG. 2, an application (210) can transmit application traffic, in which at least one of APPID, DNN, and CC is set and at least one of FQDN, target IP, and Non-IP information is included, to a UE router (220). The UE router (220) can set up and / or manage a first PDU session (PDU session#1) (221) and a second PDU session (PDU session#2) (223).

[0085] According to one embodiment, the first PDU session (221) may be mapped to at least one of the first S-NSSAI, the first DNN, and the first SSC (Session and Service Continuity). According to one embodiment, the second PDU session (223) may be mapped to at least one of the second S-NSSAI, the second DNN, and 3GPP.

[0086] The URSP handler (230) can perform an operation related to the application (210) and at least one of 1) to 3) below.

[0087] 1) Explicit API (Application Programming Interface) calls provided by the operating system to applications, for example, APIs requesting specific network usage or APIs for network socket connections.

[0088] 2) DNS (Domain Name System) query

[0089] 3) Detection based on application status monitoring

[0090] 4) Information obtained from network traffic generated by the application (e.g., source and destination IP addresses)

[0091] 5) Ethernet MAC address

[0092] The URSP handler (230) can connect and / or interact with the NAS SM (Non-Access-Stratum session management) (240).

[0093] FIG. 3 is a diagram illustrating a 5GC-EPC scenario according to one embodiment of the present disclosure.

[0094] Referring to FIG. 3, a wireless communication system (300) including EPC and 5GC may include a terminal (301), E-UTRAN (302), MME (303), S-GW (304), SMF / PGW-C (305), SM-PCF (306), NG-RAN (307), AMF (308), and UE-PCF (309).

[0095] When connecting to the EPC network, the terminal (301) can transmit URSP applicable capabilities to the SMF / PGW-C (305) at the time of Initial Attach or the first PDN connection.

[0096] The terminal (301) can receive the URSP rule transmitted from the UE-PCF (309) in the attach procedure or the initial PDN connection creation procedure. According to one embodiment, the URSP rule may include S-NSSAI information.

[0097] The terminal (301) may perform a connection request for a PDN connection that conforms to the URSP rules. According to one embodiment, the PDN connection request may include a PDU Session ID and APN information. The MME (303) may receive a PDN Context creation request through the S-GW (304). At this time, if it conforms to the URSP rules, only APN information may be included. The terminal (301) may not include S-NSSAI information when connecting the PDN connection.

[0098] The SMF / PGW-C (305) can receive a PDN connection request received from the terminal (301), associate S-NSSAI information associated with the APN, and transmit the associated S-NSSAI in the PDN connection request response message to the terminal (301). If multiple S-NSSAIs are associated with one APN, the PGW-C / SMF (305) can determine that there is a possibility that an S-NSSAI that does not conform to the URSP rule transmitted to the terminal (301) is associated.

[0099] When the terminal (301) moves to an area where 5GC is available, the network slice in 5GC can be changed to an available area.

[0100] The terminal (301) can transmit a registration request message including a PDU Session ID to the AMF (308) of the 5GC. The terminal (301) can continuously use the session service from the same SMF. The PDN connection associated with the app in the terminal (301) can be maintained when moving to the 5GC. In this case, the URSP rule transmitted to the terminal (301) from the EPC associated with the app and the S-NSSAI information associated with the app in the actual terminal may not match.

[0101] The UE-PCF (309) knows the URSP rules, and the SMF (305) knows the PDU session variables including the S-NSSAI corresponding to the RSC, but the UE-PCF (309) and the SMF (305) may not be connected to each other.

[0102] Even if the PDU session variable requested by the terminal (301) is received in SMF (305), it is not possible to know which rule the request is based on or which application the request is for.

[0103] In 5GC, SM-PCF (306) can be connected to SMF (305) and can perform a function of transmitting PCC rules and session-related policies including session-related QoS information to SMF (305). According to one embodiment, different SMFs may exist for each session of a terminal, and similarly, multiple SM-PCFs may exist. According to one embodiment, SM-PCF (306) may not be the same PCF as UE-PCF (309). UE-PCF (309) is a PCF that performs a role of storing and managing terminal policies, and logically, only one PCF may exist for one terminal.

[0104] The UE-PCF (309) performs the function of distributing terminal policies, such as URSP and ANDSP, to the terminal (301), and, like the AM-PCF that manages policies for Access Network and Mobility, such as Non-allowed Service Area and RFSP for the terminal (301), there can be one PCF logically per terminal.

[0105] In the present disclosure, the UE-PCF (309) may be the same NF as the AM-PCF. According to one embodiment, the function of the UE-PCF (309) may be performed in the AM-PCF.

[0106] FIGS. 4A to 4C are diagrams illustrating a procedure for receiving URSP association information of a terminal and recovering slice mismatch in an EPC network according to one embodiment of the present disclosure.

[0107] Figure 4a illustrates URSP provisioning within the EPC (operations 401 to 421), Figure 4b illustrates UE-requested additional PDN connectivity (operations 422 to 432), and Figure 4c illustrates Update 5GC Associated Session Parameter (operations 433 to 443).

[0108] Referring to FIG. 4a, in operation 401, the terminal may transmit its capability information to the MME during the Attach process or the first PDN connection creation process in order to transmit S-NSSAI selection information corresponding to the URSP when creating or changing a PDN connection in the EPC. The capability information transmitted to the MME may be transmitted to the PGW-C / SMF via the S-GW.

[0109] According to one embodiment, the capability information transmitted by the terminal may include at least one of the following indicators:

[0110] - URSP provisioning support indication (UPSI): UPSI is an indicator that indicates whether the UE can receive URSP rules from the EPC network. Using this indicator, the UE can express its ability to transmit S-NSSAI information included in the path selection element within the URSP rule along with a PDN connection creation request when it detects an application corresponding to the URSP rule.

[0111] - URSP Associated Session Parameter Info Reporting Support Indication (URSI): URSI is an indicator that indicates the function of reporting parameters of the corresponding URSP path selection that are supported only in the 5GC network when the terminal detects an application corresponding to the URSP rule in the EPC network. For example, this indicator indicates the function of including S-NSSAI selection information in the PDN creation or modification request message when it is included in the terminal path selection element. The terminal that has transmitted this indicator can transmit S-NSSAI selection information in the PDN connection creation request in the EPC when it detects an application corresponding to the URSP rule. The terminal capability indicated by this indicator may be regarded as a function included in the UPSI. In such a case, if the terminal provides UPSI, the terminal can transmit parameters associated with the URSP (e.g., S-NSSAI) in the PDN connection request or modification request.

[0112] - URSP enforcement reporting Support Indication in EPC (UERSI): UERSI is an indicator that indicates the function (capability) of reporting a URSP enforcement report when a terminal detects an application corresponding to a URSP rule in the EPC network. A terminal that transmits this indicator can include URSP enforcement reporting information in a PDN connection creation request in EPC and transmit it to PGW-C / SMF when it detects an application corresponding to a URSP rule. In addition, a terminal that transmits this indicator can include URSP enforcement reporting information in a PDU session creation request in 5GC and transmit it to PGW-C / SMF when it detects an application corresponding to a URSP rule. URSP enforcement reporting information can include Connection Capability in the Traffic Descriptor of the URSP. EPC can transmit S-NSSAI information together with Connection Capability.

[0113] In operation 402, the MME may include the ePCO received from the UE in a session creation request message and forward it to the S-GW. In one embodiment, the message included in the ePCO may include at least one of the information (UPSI, URSI, UERSI) included in the UE Policy Container included in operation 401.

[0114] In operation 403, the S-GW may include the ePCO received from the MME in the session creation request message and forward it to the first PGW-C / SMF (PGW-C / SMF#1). The message included in the ePCO may include at least one of the information (UPSI, URSI, UERSI) included in the UE Policy Container in operation 401.

[0115] In operation 404, the first PGW-C / SMF (PGW-C / SMF#1) may forward an SM Policy Control Creation Request message to the first SM-PCF (SM-PCF#1). The SM Policy Control Creation Request message may include at least one of the UE Policy Container information (UPSI, URSI, UERSI) received by the PGW-C / SMF from the terminal.

[0116] In operation 405, the SM-PCF may send a UE-PCF a UE Policy Control Creation Request message. The UE Policy Control Creation Request message may include at least one of the UE Policy Container information (UPSI, URSI, UERSI) received by the PGW-C / SMF from the UE.

[0117] In operation 406 to operation 410, a response message according to a message protocol between entities may be transmitted. In operation 406, the UE-PCF may transmit a terminal policy control creation response message to the first SM-PCF (SM-PCF#1). In operation 407, the first SM-PCF (SM-PCF#1) may transmit a SM policy control creation response message to the first PGW-C / SMF (PGW-C / SMF#1). In operation 408, the first PGW-C / SMF (PGW-C / SMF#1) may transmit a creation session response message to the S-GW. In operation 409, the S-GW may transmit the creation session response message to the MME. In operation 410, the MME may transmit an attach accept message to the UE.

[0118] In operation 411, the UE-PCF may create a URSP rule for the terminal connected from the EPC and send the URSP rule to the first SM-PCF (SM-PCF#1) by including it in a terminal policy control update notification message.

[0119] In operation 412, the first SM-PCF (SM-PCF#1) can forward the URSP rule to the first PGW-C / SMF (PGW-C / SMF#1).

[0120] In action 413 to action 414, the first PGW-C / SMF (PGW-C / SMF#1) may include the URSP rule in the ePCO and forward it to the MME via the S-GW.

[0121] In operation 415, the MME may transmit the URSP rules to the UE by including them in the ePCO in the EPS Bearer Context Request message. The UE may receive the URSP rules included in the EPS Bearer Context Request message in the EPC.

[0122] In operation 416, the terminal can store the URSP rule. The received URSP rule includes the Traffic Descriptor and RSC information, and the RSC information can include S-NSSAI information.

[0123] In operation 417 to operation 421, the UE may transmit a response to the URSP rule reception to the UE-PCF via the MME, the S-GW, the first PGW-C / SMF (PGW-C / SMF#1), and the first SM-PCF (SM-PCF#1). In operation 417, the UE may transmit an EPS bearer context response message including the URSP delivery result to the MME. In operation 418, the MME may transmit an EPS bearer context response message including the URSP delivery result to the S-GW. In operation 419, the S-GW may transmit an update bearer response message including the URSP delivery result to the first PGW-C / SMF (PGW-C / SMF#1). In operation 420, the first PGW-C / SMF (PGW-C / SMF#1) may transmit an SM Policy Control Update Request message including the URSP delivery result to the first SM-PCF (SM-PCF#1). In operation 421, the first SM-PCF (SM-PCF#1) may transmit a UE Policy Control Update Request message including the URSP delivery result to the UE-PCF.

[0124] Referring to FIG. 4b, in operation 422, the terminal can detect an application that conforms to the URSP rule. The URSP logic can detect the application.

[0125] In operation 423, the UE may transmit a PDN connection request message including an ePCO (at least one of a PDU session ID, URSP association information, and URSP Enforcement Report information) to the MME. If the EPC supports URSP reception or the EPC supports URSP enforcement reporting, the UE may include the S-NSSAI included in the RSC matching the Traffic Descriptor of the received URSP rule in the ePCO and forward it to the SMF / PGW-C. Since the forwarded content is included in the ePCO, it can be forwarded to the SMF / PGW-C through the MME.

[0126] According to one embodiment, when the terminal transmits URSI in operation 401 to operation 410, i.e., when the terminal detects an application corresponding to a URSP rule in the EPC network, and supports a function of reporting a parameter (e.g., S-NSSAI) supported only in the 5GC network among the path selection parameters of the corresponding URSP, the session information (e.g., S-NSSAI) included in the URSP RCS can be transmitted in the URSP associated session information (corresponding to A. URSP Associated Info indicated in operation 423 of FIG. 4).

[0127] According to one embodiment, when the terminal transmits UERSI in operation 401 to operation 410, i.e., when the EPC supports URSP enforcement reporting (B. URSP Enforcement Report information indicated at 423 in FIG. 4), the terminal may include traffic descriptor information in a URSP rule corresponding to the application in the information for URSP enforcement reporting. The terminal may include Connection Capability information, which is one of the Traffic Descriptors of the URSP, in the URSP enforcement reporting information. The URSP enforcement reporting information may additionally include at least one of S-NSSAI, APN, and SSC Mode, which are RSC information matching the URSP Traffic Descriptor.

[0128] In operation 424, the MME may select a PGW-C / SMF based on the contents of the PDN connection request message (e.g., APN value), the location of the UE, and subscriber information about the UE. The MME may send a Create Session Request message including the ePCO received from the UE to the S-GW. The Create Session Request message may include a PDU session ID. The Create Session Request message may include URSP associated session information (A), URSP enforcement report information (B), or both. The information included in the Create Session Request message may be delivered to the second PGW-C / SMF (PGW-C / SMF#2) via the S-GW.

[0129] In operation 425, the S-GW can forward a Create Session Request message to the second PGW-C / SMF (PGW-C / SMF#2). The second PGW-C / SMF (PGW-C / SMF#2) can check the contents included in the ePCO transmitted from the UE. The second PGW-C / SMF (PGW-C / SMF#2) can receive at least one of a PDU Session ID, URSP associated session information (A), and URSP enforcement report information (B) from the UE. The S-NSSAI information is information transmitted from the UE, received through the MME and the S-GW, and can be included in the URSP associated session information and transmitted.

[0130] The second PGW-C / SMF (PGW-C / SMF#2) can associate one S-NSSAI among the S-NSSAIs associated with the APN from the APN information. This association task can be regarded as a task of pre-selecting an appropriate S-NSSAI when the terminal moves to 5GC. When the second PGW-C / SMF (PGW-C / SMF#2) selects an S-NSSAI associated with the APN, the second PGW-C / SMF (PGW-C / SMF#2) can make a decision by referring to the S-NSSAI information that conforms to the URSP rule transmitted by the terminal. Alternatively, the second PGW-C / SMF (PGW-C / SMF#2) can select an S-NSSAI through information included in a URSP Enforcement report reported by the terminal.

[0131] In operation 426, the second PGW-C / SMF (PGW-C / SMF#2) can create or modify a session for SM policy with the second SM-PCF (SM-PCF#2). The second PGW-C / SMF (PGW-C / SMF#2) can forward URSP associated session information (A) and / or URSP enforcement report information (B) received from the terminal to the second SM-PCF (SM-PCF#2). Information included in the URSP enforcement report can be CC or S-NSSAI. Alternatively, if the terminal supports URSP enforcement report in the EPC, the terminal can report routing selection elements including APN, S-NSSAI, SSC Mode, etc. included in the selected URSP rule together with CC, which is a Traffic Descriptor that conforms to the URSP. Information reported by the second PGW-C / SMF (PGW-C / SMF#2) to the second SM-PCF (SM-PCF#2) may include PDU Session ID and URSP Enforcement Report information. The URSP enforcement Report information may include CC information and / or S-NSSAI information.

[0132] In operation 427, the second SM-PCF (SM-PCF#2) can send a session-related policy control creation response message to the second PGW-C / SMF (PGW-C / SMF#2). The second SM-PCF (SM-PCF#2) can transmit the session-related policy including S-NSSAI information to be used in the session. The second SM-PCF (SM-PCF#2) can transmit a policy for selecting an S-NSSAI that can be associated with the current session to the second PGW-C / SMF (PGW-C / SMF#2) from information such as S-NSSAI, APN, CC, etc. included in the URSP-related session information reported by the terminal or the URSP enforcement report information.

[0133] In operation 428, the second PGW-C / SMF (PGW-C / SMF#2) may select the S-NSSAI value associated with the APN information, which is the session information requested by the current terminal.

[0134] In one embodiment, the information used by the second PGW-C / SMF (PGW-C / SMF#2) to associate S-NSSAI is as follows.

[0135] - Subscriber information of the terminal, for example, subscribed APN information of the terminal, UE Usage Type

[0136] - Information requested in the terminal's PDN Connectivity request message: APN

[0137] - Terminal PDU Session identifier information: PGW-C / SMF can be used to determine whether a terminal is an interworking terminal.

[0138] - URSP related information transmitted by the terminal: Attribute information of the PDU session that the terminal must use in the 5GC network, such as S-NSSAI.

[0139] - URSP enforcement information transmitted by the terminal: Traffic descriptor information that conforms to the URSP rules (e.g., CC information)

[0140] The second PGW-C / SMF (PGW-C / SMF#2) can include the associated S-NSSAI information in the Create Session response message and transmit it to the S-GW.

[0141] In operation 429, the S-GW may forward the contents of the message received from the second PGW-C / SMF (PGW-C / SMF#2) to the MME.

[0142] In operation 430, the MME may send a PDU connection grant message to the UE. The PDU connection grant message may include S-NSSAI information that can be used when the UE moves to 5GC.

[0143] In operation 431, the second SM-PCF (SM-PCF#2) can search for or confirm the UE-PCF of the current terminal. The second SM-PCF (SM-PCF#2) can receive information about the UE-PCF from the second PGW-C / SMF (PGW-C / SMF#2). Alternatively, the second SM-PCF (SM-PCF#2) can query the BSF (Binding Support Function) with the terminal identifier to find the UE-PCF. Alternatively, when an SM-Policy connection for the terminal is created from the UE-PCF, the second SM-PCF (SM-PCF#2) may receive a join request message from the UE-PCF requesting a report on this, and thus may already know the address of the UE-PCF. The second SM-PCF (SM-PCF#2) may report URSP associated session information and / or URSP enforcement report information received from the second SMF / PGW-C (SMF / PGW-C#2) to the UE-PCF in operation 424.

[0144] The second SM-PCF (SM-PCF#2) may set a Policy Control Request Trigger (PCRT) that specifies a condition for requesting a report on information included in a URSP rule selected from a terminal by the second PGW-C / SMF (PGW-C / SMF#2) based on the URSP rule, and transmit the PCRT to the second PGW-C / SMF (PGW-C / SMF#2). The information included in the URSP rule may include a CC or S-NSSAI value. When the second SM-PCF (SM-PCF#2) receives URSP enforcement report information related to a PDN connection request requested by the terminal to the UE-PCF, or S-NSSAI included in the URSP enforcement report information, or S_NSSAI information related to a PDN connection request separately, the second SM-PCF may report this to the UE-PCF.

[0145] In operation 432, the UE-PCF can check the URSP enforcement report information received from the second SM-PCF (SM-PCF#2) and the URSP rules for the subscriber terminal stored in the UDR to determine whether the application detected in the current terminal is mapped to a PDU session that conforms to the URSP. In one embodiment, if the UE-PCF determines a mismatch with the URSP rules, it can transmit a message requesting modification of S-NSSAI or reallocation or re-configuration of S-NSSAI to the second SM-PCF (SM-PCF#2).

[0146] Referring to FIG. 4c, in operation 433, the UE-PCF may initiate a reporting procedure for the terminal to detect a URSP mismatch.

[0147] In operation 434, the UE-PCF may transmit a message requesting a mismatch detection report or a session renewal request to the second SM-PCF (SM-PCF#2). The message may include at least one of a terminal identifier, a PDU session identifier, an APN, a CC, a new S-NSSAI, and information on the S-NSSAI to be changed.

[0148] In operation 435, the second SM-PCF (SM-PCF#2) may forward a session-related policy update notification message to the second PGW-C / SMF (PGW-C / SMF#2). The session-related policy update notification message may include 5GC-related session information update information (or new 5GC-related session parameters) (e.g., S-NSSAI information).

[0149] In operation 436 or 437, the second PGW-C / SMF (PGW-C / SMF#2) may forward 5GC-related session information update information to the MME via the S-GW. In operation 436, the second PGW-C / SMF (PGW-C / SMF#2) may transmit an Update Bearer Request message including new 5GC-related session parameters (e.g., S-NSSAI information) to the S-GW. In operation 437, the S-GW may transmit an Update Bearer Request message including new 5GC-related session parameters (e.g., S-NSSAI information) to the MME.

[0150] In operation 438, the MME may send an EPS Bearer Context Request message containing new 5GC related session parameters (e.g., S-NSSAI information) to the UE.

[0151] In actions 439 to 441, the terminal may transmit an EPS Bearer Context response message to the second PGW-C / SMF (PGW-C / SMF#2) via the MME and S-GW.

[0152] In operation 442, when the change is completed, the second PGW-C / SMF (PGW-C / SMF#2) can report the changed URSP association information (A) to the second SM-PCF (SM-PCF#2).

[0153] In operation 443, the second SM-PCF (SM-PCF#2) may report the changed URSP association information (A) and PDU session ID to the UE-PCF.

[0154] FIGS. 5A to 5C are diagrams illustrating a procedure for receiving URSP association information of a terminal and recovering slice mismatch after moving to a 5GC network according to one embodiment of the present disclosure.

[0155] Referring to FIG. 5A, in operation 501, the terminal can access the EPC network, receive URSP rules from the EPC network through an EPS Attach procedure or a PDU connection procedure, and store the received URSP rules. In operation 501, the terminal can perform URSP provisioning with at least one of the MME, the S-GW, the first PGW-C / SMF (PGW-C / SMF#1), the first SM-PCF (SM-PCF#1), and the UE-PCF during the EPS Attach procedure or the PDU connection procedure in the EPC network.

[0156] In operation 502, the terminal can detect an application that conforms to the URSP rules. The URSP logic can detect the application.

[0157] In operation 503, the terminal can create a PDN connection in the EPC network according to the detected URSP rule. Although the URSP rule includes S-NSSAI, the terminal can only transmit the APN because it is an EPC network. The PGW-C / SMF, which receives the PDN connection establishment request requested by the terminal, can select one of the S-NSSAIs associated with the APN requested by the terminal as the associated information. The PGW-C / SMF transmits the selected associated S_NSSAI information to the terminal. In operation 503, the terminal can perform a UE-initialized additional PDN connection establishment procedure. The second PGW-C / SMF (PGW-C / SMF#2) can associate the PDN connection with the S-NSSAI and transmit the S-NSSAI to the terminal. In one embodiment, the second SM-PCF (SM-PCF#2) may set a Policy Control Request Trigger (PCRT) and transmit it to the second PGW-C / SMF (PGW-C / SMF#2).

[0158] In operation 504, when the terminal creates a PDN connection in the EPC network, the terminal may store URSP-related information (e.g., at least one of matching CC information, RSC information for the matched URSP, and S-NSSAI information) corresponding to the created PDU session together with the associated PDN Session ID. The terminal may check whether the S-NSSAI information received from the PGW-C / SMF is one of the S-NSSAIs included in the matching URSP rule that triggered the corresponding PDN connection in the terminal. If the S-NSSAI associated with the PDN connection received from the PGW-C / SMF is not included in the URSP rule that triggered the creation request of the corresponding PDN connection, or is different from the S-NSSAI included in the URSP rule, the terminal may record URSP mismatch information. Alternatively, the terminal may store URSP-related information for all PDN connections created through the URSP function together with the PDU Session identifier. The URSP association information stored for each generated PDN connection may include CC and S-NSSAI information included in the matching URSP rule, and in the case of S_NSSAI, if it is different from the S-NSSAI information of the generated PDN connection, it may be displayed and stored together.

[0159] Referring to FIG. 5b, when the terminal moves to the 5G network in operation 505, the terminal may transmit a registration request message to the 5GC in operation 506. If the terminal connects to the 5GC network after creating a PDN connection based on the URSP rule in the EPC, the terminal may transmit the 5GC registration request message including URSP association information per PDU session. According to one embodiment, the URSP association information per PDU session may include PDU Session ID and S-NSSAI information or PDU Session ID and URSP Traffic Descriptor information (e.g., Connection Capability information). The information transmitted from the terminal to the AMF may be transmitted as included in the list information of PDU sessions to be reactivated, or may be transmitted as included in the UE Policy Container information transmitted by the terminal to the UE-PCF. The AMF may receive a URSP Enforcement Report from the terminal and report it directly to the UE-PCF or to the SM-PCF. If the terminal provides the URSP Enforcement Report Supporting Indicator (UERSI), it may include the URSP Enforcement Report Supporting Indicator (URSP Enforcement Report Supporting Indicator) in the registration request message and transmit it to the AMF.

[0160] In operation 507, the AMF may send a UE Policy Control Creation Request message to the UE-PCF, requesting the creation of a policy control connection for the terminal. The UE Policy Control Creation Request message may include a URSP Enforcement Report Supporting Indicator (UERSI) received by the AMF from the terminal.

[0161] In operation 508, the UE-PCF may send a Policy Control Request Trigger (PCRT) to the AMF requesting that the UE receive a URSP association report generated by the EPC.

[0162] In operation 509, the AMF receives a PCRT requesting the receipt of a URSP association report generated in the EPC from the UE-PCF, and when it receives URSP-related information associated with each PDU session from the terminal, it can report to the UE-PCF the CC information associated with each PDU session ID or the S-NSSAI information associated with each PDU session.

[0163] Action 511 to Action 513 are procedures in which the AMF receives URSP association information per PDU session (e.g., S-NSSAI, CC matched in EPC) included in a registration request message from the terminal, transmits the URSP association information per PDU session to the second PGW-C / SMF (PGW-C / SMF#2) (or SMF), and the second PGW-C / SMF (PGW-C / SMF#2) (or SMF) reports the URSP association information per PDU session to the second SM-PCF (SM-PCF#2).

[0164] In operation 511, the AMF may forward a PDU session renewal request message to the second PGW-C / SMF (PGW-C / SMF#2) (or SMF) including URSP association information per PDU session and S-NSSAI S-NSSAI(S-NSSAI#2) information associated with the created PDU session (or PDN connection). The URSP association information per PDU session may include S-NSSAI and CC values ​​included in the URSP rule that triggered the creation of the PDU session in accordance with the URSP rule at the terminal. This information may include PDU Session ID, S-NSSAI(S-NSSAI#1), and CC information. The S-NSSAI#2 for the created PDU session and the S-NSSAI#1 information included in the URSP association information per session may have different information values.

[0165] In operation 512, the second PGW-C / SMF (PGW-C / SMF#2) (or SMF) may receive URSP association information per PDU session from the terminal, and report the URSP association information per PDU session and S-NSSAI (S-NSSAI#2) to the second SM-PCF (SM-PCF#2). According to one embodiment, during the SM Policy Control connection creation process between the second SM-PCF and the second PGW-C / SMF prior to operation 512, the second SM-PCF may set up a PCRT (Policy Control Request Trigger) for performing SM Policy change upon URSP association information or a URSP Enforcement Report for terminal path selection policy to the second PGW-C / SMF (PGW-C / SMF#2).

[0166] In operation 513, the second SM-PCF (SM-PCF#2) may report URSP association information and S-NSSAI (S-NSSAI#2) per PDU session to the UE-PCF.

[0167] In one embodiment, operations 507 to 510 may be procedures for transmitting a list of multiple PDU sessions at once, and operations 511 to 513 may be procedures performed for each individual PDU session. In one embodiment, operations 507 to 510 and operations 511 to 513 may be performed selectively.

[0168] In operation 514, UE-PCF can check URSP association information per PDU session received from the terminal through AMF or URSP association information per PDU session received from SM-PCF. UE-PCF can check whether URSP rule matches based on S-NSSAI (S-NSSAI#1) and S-NSSAI (S-NSSAI#2). UE-PCF can store PSI for the terminal in UDR. It can store Capability of the terminal transmitted by the terminal. Information that UE-PCF stores for each terminal in UDR can be Capability information on whether EPC-5GC IWK terminal can receive URSP rule in EPC network, information on whether EPC-5GC IWK terminal supports URSP enforcement report, or information on whether terminal can transmit S-NSSAI information when connecting to PDN in EPC network.

[0169] Referring to Figure 5c, in operation 515, the UE-PCF may detect a mismatch in the URSP rules. The UE-PCF may determine that the URSP mismatch is due to the allocation of S-NSSAI. The UE-PCF may initiate a procedure for reallocation or reselection of the network slice.

[0170] In operation 516, the UE-PCF may send a request to the AMF to trigger a procedure to update the policy settings for a slice change. The UE-PCF may send a message to the AMF containing information reporting a URSP mismatch. The information reporting a URSP mismatch may include information for identifying the PDU sessions of the UE that need to be modified based on a URSP rule mismatch determination.

[0171] According to one embodiment, information for identifying a PDU session may include the following information:

[0172] - Terminal identifier (UE ID, group of UE ID, any UE)

[0173] - PDU session identifier for individual terminal identification

[0174] - URSP Mismatch Report Information: Current S-NSSAI, S-NSSAI to be corrected

[0175] - Suggestions for improving URSP mismatch: Information about the PDU session for which the corresponding PDU session identifier should be changed, e.g. S-NSSAI, SSC Mode, etc. to be modified.

[0176] AMF can receive a request for a slice change from UE-PCF or a report information on a URSP mismatch from UE-PCF and send a PDU Session Modification Request message to SMF. The message that AMF sends to SMF is a message requesting a change of a slice for an existing PDU session of a slice, and the contents of the message can include PDU Session ID, current S-NSSAI information, S-NSSAI information to be changed, and a reason for requesting a change. The reason for requesting a change can include a UE-PCF policy or indicate recovery from a URSP mismatch.

[0177] In operation 517, the SMF may receive a request for a slice change from the AMF and perform a PDU session change procedure. The SMF may transmit a PDU session change command to the terminal. The PDU session change command transmitted by the SMF to the terminal may include a content indicating a change in S-NSSAI.

[0178] In operation 518, AMF can receive a PDU session change command message from SMF and forward it to the terminal.

[0179] In operation 519, the terminal may receive an S-NSSAI change instruction from the AMF included in a PDU session change command message received from the SMF, and perform a change to the S-NSSAI. The S-NSSAI for the terminal's session may be changed.

[0180] In operation 520, the terminal may send a response message to the PDU session change command. The AMF may forward the PDU session change request to the SMF.

[0181] In operation 521, the SMF can receive a response to a PDU session change command transmitted from the terminal via the AMF. The SMF can successfully perform a slice change for the PDU session and report the slice change.

[0182] In operation 522, the SMF may report a slice change to the SM-PCF and report information including the changed S-NSSAI.

[0183] In operation 523, the SM-PCF may report a slice change to the UE-PCF. The report may include changed slice information S-NSSAI information.

[0184] In operation 524, if the S-NSSAI for the PDU Session has changed, the terminal detects that the Slice Availability has changed, and the terminal can perform a re-evaluation of the URSP rules for the applications associated with the corresponding S-NSSAI.

[0185] In operation 525, if the terminal provides the URSP Enforcement reporting capability and performs URSP re-evaluation for a PDU Session with a changed slice, the application may be associated with the same PDU Session as a result of the URSP re-evaluation, or may be associated with another PDU Session. If the terminal is associated with another PDU Session as a result of the URSP re-evaluation, the terminal may forward the URSP enforcement report information for the newly associated PDU Session to the SMF by including it in the PDU Session Modification Request message. The URSP enforcement report information included in the PDU Session Modification Request message may include a CC value matched to the URSP.

[0186] In operation 526, the SMF that received the URSP enforcement report as a result of URSP re-evaluation at the terminal can forward it to the SM-PCF.

[0187] In operation 527, if SM-PCF receives a subscription request for URSP enforcement reporting from UE-PCF, it may report it to UE-PCF.

[0188] According to one embodiment, the operations illustrated in FIG. 5B (at least one of operations 506 to 514) may be performed after the operations illustrated in FIG. 4B (at least one of operations 422 to 432). According to another embodiment, the operations illustrated in FIGS. 5A and 5B may be performed after the operations illustrated in FIGS. 4A and 4B.

[0189] Figure 6 is a block diagram showing the structure of a terminal according to an embodiment of the present invention.

[0190] The terminal described with reference to FIGS. 1 to 5B may correspond to the terminal of FIG. 6. Referring to FIG. 6, the terminal may be composed of a transceiver (610), a memory (620), and a control unit (630). Depending on the communication method of the terminal described above, the transceiver (610), the control unit (630), and the memory (620) of the terminal may operate. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the transceiver (610), the control unit (630), and the memory (620) may be implemented in the form of a single chip. In addition, the control unit (630) may include one or more processors.

[0191] The transceiver (610) is a general term for the receiving unit and the transmitting unit of the terminal, and can transmit and receive signals with a base station, a network entity, a server, or another terminal. The signals transmitted and received with the base station, network entity, server, or other terminal may include control information and data. To this end, the transceiver (610) may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-downconverts a received signal. However, this is only one embodiment of the transceiver (610), and the components of the transceiver (610) are not limited to an RF transmitter and an RF receiver.

[0192] In addition, the transmitter / receiver unit (610) can receive a signal through a wireless channel and output it to the control unit (630), and transmit the signal output from the control unit (630) through the wireless channel.

[0193] The memory (620) can store programs and data necessary for the operation of the terminal. In addition, the memory (620) can store control information or data included in signals acquired from the terminal. The memory (620) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, the memory (620) may not exist separately but may be configured as part of the processor (630).

[0194] The control unit (630) can control a series of processes so that the terminal can operate according to the embodiments of the present disclosure described above.

[0195] FIG. 7 is a block diagram showing the structure of a network entity according to an embodiment of the present invention.

[0196] The network entity described with reference to FIGS. 1 to 5b may correspond to the network entity of FIG. 7. For example, the network entity of FIG. 7 may be implemented as any one of the MME, S-GW, PGW-C / SMF, SM-PCF, UE-PCF, and BSF described above in FIGS. 1 to 5b.

[0197] Referring to FIG. 7, a network entity may be composed of a transceiver (710), a memory (720), and a control unit (730). Depending on the communication method of the network entity described above, the transceiver (710), the control unit (730), and the memory (720) of the network entity may operate. However, the components of the server are not limited to the examples described above. For example, the network entity may include more or fewer components than the components described above. In addition, the transceiver (710), the control unit (730), and the memory (720) may be implemented in the form of a single chip. In addition, the control unit (730) may include one or more processors.

[0198] The transceiver (710) is a general term for the receiving unit and the transmitting unit of the network entity, and can transmit and receive signals with a terminal or other network entity. The signals transmitted and received with the terminal or other network entity may include control information and data. To this end, the transceiver (710) may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, this is only one embodiment of the transceiver (710), and the components of the transceiver (710) are not limited to the RF transmitter and RF receiver.

[0199] In addition, the transmitter / receiver unit (710) can receive a signal through a wireless channel and output it to the control unit (730), and transmit the signal output from the control unit (730) through the wireless channel.

[0200] The memory (720) can store programs and data required for the operation of the network entity. Furthermore, the memory (720) can store control information or data included in signals acquired from the network entity. The memory (720) may be configured as a storage medium, such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. Furthermore, the memory (720) may not exist separately but may be included in the processor (730).

[0201] The control unit (730) can control a series of processes so that the network entity can operate according to the embodiments of the present disclosure described above.

[0202] FIG. 8 is a flowchart showing the operation of a terminal according to one embodiment of the present disclosure.

[0203] The terminal of FIG. 8 can be implemented as the UE illustrated in FIGS. 4a to 4c, and / or the UE illustrated in FIGS. 5a to 5c.

[0204] Referring to FIG. 8, in operation 801, the terminal may transmit a first message (attach request) to a mobility management entity (MME) that includes at least one of a first indicator (URSI) indicating support for reporting on URSP associated session information and a second indicator (UERSI) indicating support for URSP enforcement report.

[0205] In operation 803, the terminal may receive a second message (EPS bearer context request) including a URSP rule from the MME.

[0206] In operation 805, the terminal may transmit a third message (PDN connectivity request) including at least one of the URSP associated session information and the URSP enforcement report to the MME.

[0207] In one embodiment, the URSP rule relates to the UE connected to the evolved packet coreC (EPC) and may be generated by a UE-PCF (policy control function).

[0208] In one embodiment, the third message may further include a protocol data unit (PDU) session ID.

[0209] In one embodiment, the URSP associated session information may include single-network slice selection assistance information (S-NSSAI) supported by 5GC. In one embodiment, the URSP execution report may include connection capability (CC) information of the URSP.

[0210] In one embodiment, a session created based on the third message may be associated with a 5GC PDU session parameter.

[0211] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0212] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0213] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0214] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0215] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0216] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method for operating a UE (user equipment) based on URSP (UE route selection policy) in a wireless communication system, An action of transmitting to a mobility management entity (MME) a ​​first message (attach request) including at least one of a first indicator (URSI) indicating support for reporting on URSP associated session information and a second indicator (UERSI) indicating support for URSP enforcement report; An action of receiving a second message (EPS bearer context request) including URSP rules from the MME; and A method characterized by comprising the action of transmitting a third message (PDN connectivity request) including at least one of the URSP associated session information and the URSP enforcement report to the MME.

2. In paragraph 1, A method characterized in that the above URSP rule relates to the UE connected to the EPC (evolved packet coreC) and is generated by the UE-PCF (policy control function).

3. In paragraph 1, A method characterized in that the third message further includes a PDU (protocol data unit) session ID.

4. In paragraph 1, The above URSP associated session information includes S-NSSAI (single-network slice selection assistance information) supported by 5GC, A method characterized in that the above URSP implementation report includes CC (connection capability) information of the URSP.

5. In paragraph 4, A method characterized in that a session created based on the third message is associated with a 5GC PDU session parameter.

6. In a method of operating a network entity (PGW-C / SMF) in a wireless communication system, An action of receiving a first message (create session request) from a serving gateway (S-GW) including at least one of a first indicator (URSI) indicating support for reporting on URSP (UE route selection policy) associated session information and a second indicator (UERSI) indicating support for URSP enforcement report; An operation of receiving a second message (create session request) including at least one of the URSP associated session information and the URSP enforcement report from the S-GW; and A method characterized by including an action of transmitting a third message (create session response) including S-NSSAI (single-network slice selection assistance information) to the S-GW.

7. In paragraph 6, A method further comprising an operation of associating a session with a 5GC PDU (protocol data unit) session parameter based on at least one of subscriber information of a UE (user equipment), the URSP associated session information, and the URSP enforcement report.

8. In paragraph 6, A method characterized in that the second message further includes a PDU (protocol data unit) session ID.

9. In paragraph 6, The above URSP associated session information includes S-NSSAI supported by 5GC, A method characterized in that the above URSP implementation report includes CC (connection capability) information of the URSP.

10. In paragraph 6, An operation of transmitting a fourth message for session policy control to SM-PCF (session management-policy control function) based on the second message; and A method further comprising the action of receiving a fifth message corresponding to the fourth message from the SM-PCF.

11. In a wireless communication system, in a UE (user equipment) based on URSP (UE route selection policy), Transmitter and receiver; and comprising a control unit, said control unit comprising: Control to transmit to the MME (mobility management entity) a first message (attach request) including at least one of a first indicator (URSI) indicating support for reporting on URSP associated session information and a second indicator (UERSI) indicating support for URSP enforcement report, Receive a second message (EPS bearer context request) containing URSP rules from the MME, A UE characterized in that it controls to transmit a third message (PDN connectivity request) including at least one of the URSP associated session information and the URSP enforcement report to the MME.

12. In paragraph 11, The above URSP rule relates to the UE connected to the EPC (evolved packet coreC), and is characterized in that it is generated by the UE-PCF (policy control function).

13. In paragraph 11, A UE characterized in that the third message further includes a PDU (protocol data unit) session ID.

14. In paragraph 11, The above URSP associated session information includes S-NSSAI (single-network slice selection assistance information) supported by 5GC, The above URSP implementation report is characterized in that it includes URSP CC (connection capability) information.

15. In a wireless communication system, for a network entity (PGW-C / SMF), Transmitter and receiver; and comprising a control unit, said control unit comprising: Receiving a first message (create session request) from a serving gateway (S-GW) including at least one of a first indicator (URSI) indicating support for reporting on URSP (UE route selection policy) associated session information and a second indicator (UERSI) indicating support for URSP enforcement report, Receive a second message (create session request) including at least one of the above URSP associated session information and the above URSP execution report from the S-GW, A network entity characterized by controlling to transmit a third message (create session response) including S-NSSAI (single-network slice selection assistance information) to the S-GW.

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