Method and apparatus for supporting multi-access sessions in wireless communication system

Abstract

The present invention relates to a method performed by a terminal in a wireless communication system, the method comprising the steps of: transmitting, to a session management function (SMF)+packet data network gateway control plane (PGW-C), a first message for requesting a packet data network (PDN) connection via a first access network; and receiving, from the SMF+PGW-C via the first access network, a second message including a response to the request for the PDN connection, wherein the PDN connection is on the basis of a multi-access (MA) protocol data unit (PDU) session, and the MA PDU session is associated with paths connected to a core network and a plurality of access networks including the first access network.

Description

Method and device for supporting multiple access sessions in a wireless communication system

[0001] The present disclosure relates to an apparatus and method for providing an access path in a wireless communication system or a mobile communication system, and more specifically, to a method and apparatus for providing an access traffic steering function (Access Traffic Steering, Switching, Splitting, ATSSS) in a wireless communication system.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th-generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th-generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are referred to as "Beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps, and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., the 95 GHz to 3 terahertz (3 THz) band). In the terahertz band, due to more severe path loss and atmospheric absorption compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technology capable of guaranteeing signal reach, or coverage, is expected to increase. As key technologies to ensure coverage, radio frequency (RF) devices, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multi-antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (high-altitude platform stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (artificial intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] The present disclosure provides a method and apparatus for providing an access path in a mobile communication or wireless communication system.

[0008] According to one embodiment of the present disclosure, a method for processing a control signal in a mobile communication or wireless communication system may include: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

[0009] One embodiment of the present invention provides a method and apparatus for providing an access path in a wireless communication system.

[0010] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0011] FIG. 1 illustrates the structure of a wireless communication system according to one embodiment of the present disclosure.

[0012] FIG. 2 illustrates an Access Traffic Steering, Switching, Splitting (ATSS) support structure in a wireless communication system according to one embodiment of the present disclosure.

[0013] FIG. 3a illustrates an example of a network structure and interface of an EPS (Evolved Packet System) / 5GS (5G system) interworking system according to one embodiment of the present disclosure.

[0014] FIG. 3b illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0015] FIG. 3c illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0016] FIG. 3d illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0017] FIG. 3e illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0018] FIG. 3f illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0019] FIG. 3g illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0020] FIG. 3h illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0021] FIG. 3i illustrates another example of a network structure and interface of an EPS / 5GS interworking system according to one embodiment of the present disclosure.

[0022] FIG. 4 illustrates various forms of an MA PDU Session (Multi Access Protocol Data Unit Session) according to one embodiment of the present disclosure.

[0023] FIG. 5 illustrates an example of a 5GS / EPS interworking system according to one embodiment of the present disclosure providing an ATSSS rule to a UE.

[0024] FIG. 6 illustrates an example of providing an ATSSS rule to a UE in a 5GS / EPS interworking system according to one embodiment of the present disclosure.

[0025] FIG. 7 illustrates an example of providing an ATSSS rule to a UE in a 5GS / EPS interworking system according to one embodiment of the present disclosure.

[0026] FIG. 8 illustrates the configuration of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0027] FIG. 9 illustrates the configuration of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0028] FIG. 10 illustrates the configuration of a network entity in a wireless communication system according to one embodiment of the present disclosure.

[0029] In the following description of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be omitted.

[0030] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted.

[0031] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. Furthermore, the terms described below are defined based on their functions in the present disclosure. Since the terms of the present disclosure may vary depending on the intent or convention of the user or operator, their definitions should be determined according to the content throughout the present disclosure.

[0032] Terms used in this disclosure to refer to network entities or network functions, messages, identification information, etc., are examples provided for convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0033] For convenience, the present invention uses terms and names defined in 5G system specifications, but is not limited by said terms and names and can be applied in the same way to systems conforming to other specifications.

[0034] The operating principle of the present invention is described in detail below with reference to the attached drawings.

[0035] In describing the embodiments of the present disclosure, descriptions of technical details that are well known in the technical field to which the present disclosure belongs and are not directly related to the present disclosure may be omitted. This is intended to convey the essence of the present disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0036] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual size. Identical or corresponding components in each drawing may be assigned the same reference number.

[0037] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. The embodiments provided are merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0038] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0039] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0040] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0041] In describing the present disclosure below, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present disclosure. Embodiments of the present disclosure will be described below with reference to the attached drawings.

[0042] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0043] For convenience of explanation, the present disclosure uses terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present disclosure is not limited by the above terms and names and may be applied equally to systems conforming to other standards. In the present disclosure, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as eNB may represent a gNB. Additionally, the term terminal may refer to mobile phones, NB-IoT devices, sensors, as well as other wireless communication devices.

[0044] Hereinafter, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. The terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Of course, it is not limited to the above examples.

[0045] In particular, the present disclosure is applicable to 3GPP NR (5th generation mobile communication standard). Furthermore, the present disclosure is applicable to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G communication technology and IoT-related technology. In the present invention, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as eNB may represent a gNB. Additionally, the term terminal may refer to mobile phones, NB-IoT devices, sensors, as well as other wireless communication devices.

[0046] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0047] As a representative example of a broadband wireless communication system, the LTE system employs the Orthogonal Frequency Division Multiplexing (OFDM) method for the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method for the uplink (UL). The uplink refers to a wireless link through which a terminal (User Equipment; UE or Mobile Station; MS) transmits data or control signals to a base station (eNode B or BS; Base Station), and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above multiple access method distinguishes the data or control information of each user by allocating and operating time-frequency resources to be transmitted for each user so that they do not overlap, that is, so that orthogonality is established.

[0048] As a future communication system following LTE, that is, a 5G communication system, it must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for the 5G communication system include Enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0049] According to some embodiments, eMBB may aim to provide data transmission speeds that are higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. In addition, the 5G communication system may need to provide a user-perceived data rate while simultaneously providing the peak data rate. To satisfy these requirements, the 5G communication system may require improvements in various transmission and reception technologies, including enhanced Multi-Input Multi-Output (MIMO) transmission technology. Furthermore, while current LTE transmits signals using a maximum transmission bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can satisfy the data transmission speeds required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in frequency bands of 3 to 6 GHz or above 6 GHz.

[0050] Simultaneously, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT services, mMTC may require support for a large number of terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT devices are attached to various sensors and equipment to provide communication functions, the system must be able to support a large number of terminals within a cell (e.g., 1,000,000 terminals / km²). Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones not covered by cells, such as building basements; therefore, wider coverage may be required compared to other services provided by 5G communication systems. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace terminal batteries, a very long battery life of 10 to 15 years may be required.

[0051] Finally, URLLC is a mission-critical cellular-based wireless communication service that can be used for services such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC may need to offer very low latency and very high reliability. For example, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and may simultaneously require a packet error rate of 10^-5 or less. Consequently, for services supporting URLLC, 5G systems must provide a Transmit Time Interval (TTI) smaller than other services, and design considerations may be required to allocate a wide resource in the frequency band to ensure the reliability of the communication link.

[0052] The three services considered in the aforementioned 5G communication system, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted within a single system. In this case, different transmission and reception techniques and parameters may be used between the services to satisfy the different requirements of each service. However, the aforementioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types to which the present disclosure applies are not limited to the examples mentioned above.

[0053] In addition, although embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro, or 5G (or NR, next-generation mobile communication) systems as examples, embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. Furthermore, embodiments of the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0054] Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0055] Preferred embodiments of the present disclosure are described in detail below with reference to the attached drawings. It should be noted that identical components in the attached drawings are indicated by the same reference numerals whenever possible. Furthermore, it should be noted that the drawings of the present invention attached below are provided to aid in understanding the present invention, and that the present invention is not limited to the forms or arrangements illustrated in the drawings. Additionally, detailed descriptions of known functions and configurations that may obscure the essence of the present invention will be omitted. It should be noted that in the following description, only the parts necessary for understanding the operation according to various embodiments of the present invention are described, and descriptions of other parts will be omitted so as not to distract from the essence of the present invention. Furthermore, the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), but this is merely an example for illustrative purposes. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0056] FIG. 1 illustrates the structure of a wireless communication system according to one embodiment of the present disclosure.

[0057] Referring to FIG. 1, the structure of a 5G system may include various components (i.e., network functions (NF)). FIG. 1 illustrates some of these, including an authentication server function (AUSF) device (160), a core access and mobility management function (AMF) device (120), a session management function (SMF) device (130), a policy control function (PCF) device (140), an application function (AF) device (150), a unified data management (UDM) device (170), a data network (DN) (180), a user plane function (UPF) device (110), a radio access network (R)AN (20), and a terminal, i.e., a user device (UE) (10). Also, FIG. 1 illustrates a Network Slice Selection Function (NSSF) device (190), a Network Slice Specific Authentication and Authorization Function (NSSAAF) device (195), and a Network Slice Admission Control Function (NSACF) device (196).

[0058] Each of the devices exemplified in FIG. 1 can be implemented as a single server or device, or as a network slice instance as previously described. When implemented as a network slice instance, two or more identical or different network slice instances may be implemented within a single server or device, and one network slice instance may be implemented in two or more servers or devices.

[0059] Each of the above-mentioned NFs can support the following functions.

[0060] AUSF (160) can process and store data for the authentication of UE (10).

[0061] The AMF (120) can provide functions for managing connectivity and mobility at the UE level, and can basically be connected to one AMF per UE. Specifically, the AMF (120) provides signaling between CN nodes for mobility between 3GPP access networks, termination of radio access network (RAN) CP interfaces (i.e., N2 interfaces), termination of 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 execution of paging retransmission), mobility management control (subscription and policy), support for intra-system mobility and inter-system mobility, support for network slicing, SMF selection, lawful intercept (for AMF events and interfaces to LI systems), provision of session management (SM) message delivery between the UE and the SMF, transparent proxy for SM message routing, access authentication, access authorization including roaming authorization checks, and the UE and It can support functions such as providing SMS message delivery between SMSFs (Short Message Service Functions), security anchor functions (SAFs), and / or security context management (SCM). Some or all of these functions of the AMF (120) may be supported within a single AMF instance operating as a single AMF.

[0062] DN (180) may mean, for example, operator services, internet access, or third-party services. DN (180) can transmit downlink protocol data units (PDUs) to UPF (110) or receive PDUs transmitted from UE (10) through UPF (110).

[0063] PCF (140) can receive information about packet flow from an application server and provide functions to determine policies such as mobility management and session management. Specifically, PCF (140) can support functions such as supporting a unified policy framework to control network behavior, providing policy rules so that control plane function(s) (e.g., AMF, SMF, etc.) can enforce policy rules, and implementing a front end to access relevant subscription information for policy decisions within a user data repository (UDR).

[0064] The SMF (130) provides session management functions, and if a UE has multiple sessions, each session may be managed by a different SMF. Specifically, the SMF (130) may support session management (e.g., session establishment, modification, and termination including maintaining a tunnel between the UPF and the AN node), UE IP address allocation and management (optional authentication), selection and control of UP functions, traffic steering setup for routing traffic from the UPF to an appropriate destination, termination of interfaces toward policy control functions, enforcement of control portions of policies and QoS (quality of service), lawful interception (for SM events and interfaces to LI systems), termination of the SM portion of NAS messages, downlink data notification, initiator of AN-specific SM information (transmitted to AN via N2 through the AMF), determination of the session's SSC mode, roaming functions, etc. As explained above, some functions or all functions of the SMF (130) can be supported within a single SMF instance that operates as a single SMF.

[0065] The UDM (170) can store user subscription data, policy data, etc. The UDM (170) may include two parts: an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

[0066] The FE may include a UDM FE responsible for location management, subscription management, and credential processing, and a PCF-FE responsible for policy control. The UDM (170) may store data required for the functions provided by the UDM-FE and policy profiles required by the PCF. The data stored in the UDR may include user subscription data and policy data, including subscription identifiers, security credentials, access and mobility-related subscription data, and session-related subscription data. The UDM-FE may access subscription information stored in the UDR and support functions such as authentication credential processing, user identification handling, access authentication, enrollment / mobility management, subscription management, and SMS management.

[0067] UPF (110) can transmit downlink PDUs received from DN (180) to UE (10) via (R)AN (20) and transmit uplink PDUs received from UE (10) to DN (180) via (R)AN (20). Specifically, the UPF (110) can support an anchor point for intra / inter RAT mobility, an external PDU session point for interconnection to a data network, packet routing and forwarding, packet inspection and policy rule enforcement in the user plane, lawful intercept, traffic usage reporting, an uplink classifier to support routing of traffic flows to a 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 verification (SDF mapping between service data flow (SDF) and QoS flow), transport level packet marking within the uplink and downlink, downlink packet buffering and downlink data notification triggering functions. Some or all of these functions of the UPF (110) can be supported within a single UFP instance that operates as a single UPF.

[0068] AF (150) can interact with the 3GPP core network to provide services (e.g., support for application impact on traffic routing, access to network capability exposure, and interaction with policy frameworks for policy control).

[0069] (R)AN(20) can be a collective term for a new radio access network that supports both evolved E-UTRA, which is an evolved version of 4G radio access technology, and new radio access technology (new radio, NR) (e.g., gNB).

[0070] The gNB (20) performs functions for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources (i.e., scheduling) to the UE (10) in the uplink / downlink), IP (internet protocol) header compression, encryption and integrity protection of user data streams, selection of the AMF (120) upon attachment of the UE (10) when routing to the AMF (120) is not determined from the information provided to the UE (10), routing of user plane data to the UPF (110)(s), routing of control plane information to the AMF (120), connection setup and termination, scheduling and transmission of paging messages (generated from the AMF (120)), scheduling and transmission of system broadcast information (from the AMF (120) or operating and maintenance (O&M)). It can support functions such as measurement and measurement reporting settings for generated), mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data wireless bearers, support for UE (10) in inactive mode, NAS message distribution function, NAS node selection function, wireless access network sharing, dual connectivity, tight interworking between NR and E-UTRA.

[0071] UE (10) may refer to a user device. The user device may be referred to by terms such as terminal, ME (mobile equipment), MS (mobile station). Additionally, the user device may be a portable device such as a laptop, mobile phone, PDA (personal digital assistant), smartphone, multimedia device, etc., or it may be a non-portable device such as a personal computer (PC) or vehicle-mounted device. In the following description, it will be referred to as a user device (UE) or terminal.

[0072] For clarity of explanation, network exposure function (NEF) devices and NF repository function (NRF) devices are not shown in FIG. 1, but NFs can interact with NEF and NRF as needed.

[0073] Let us examine the NRF. The NRF (not shown in FIG. 1) can support a service discovery function. When a request for the discovery of a second NF is received from a first NF instance, the NRF can perform a second NF discovery operation and then provide information about the discovered second NF instance to the first NF instance. In addition, it can maintain available NF instances and the services they support.

[0074] Meanwhile, for convenience of explanation, FIG. 1 illustrates a reference model for the case where a UE (10) accesses a DN (180) using a single PDU session, but the present disclosure is not limited thereto.

[0075] The UE (10) can access two (i.e., local and central) data networks simultaneously using multiple PDU sessions. In this case, 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.

[0076] Additionally, the UE (10) may simultaneously access two data networks (i.e., local and central) provided within a single PDU session.

[0077] In 3GPP systems, a conceptual link connecting NFs within a 5G system is defined as a reference point. The following is an example of a reference point included in the structure of a 5G system illustrated in Figure 1.

[0078] - N1: Reference point between UE and AMF

[0079] - N2: Reference point between (R)AN and AMF

[0080] - N3: Reference point between (R)AN and UPF

[0081] - N4: Reference point between SMF and UPF

[0082] - N5: Reference point between PCF and AF

[0083] - N6: Reference point between UPF and the data network

[0084] - N7: Reference point between SMF and PCF

[0085] - N8: Reference point between UDM and AMF

[0086] - N9: Reference point between 2 core UPFs

[0087] - N10: Reference point between UDM and SMF

[0088] - N11: Reference point between AMF and SMF

[0089] - N12: Reference point between AMF and AUSF

[0090] - N13: Reference point between UDM and the authentication server function (AUSF)

[0091] - N14: Reference point between 2 AMFs

[0092] - N15: Reference point between PCF and AMF in non-roaming scenarios, reference point between PCF and AMF within the visited network in roaming scenarios

[0093] In the following description, the term "terminal" may refer to the UE (10), and the terms UE or terminal may be used interchangeably. In such cases, unless the terminal is additionally defined, it should be understood as the UE (10).

[0094] A terminal establishes a session by connecting to a data network (e.g., a network providing internet services) through a 5G system, and each data network can be distinguished using an identifier called a DNN (Data Network Name). The DNN can be used to determine NFs related to the user plane, interfaces between NFs, and operator policies when the terminal establishes a session with the network system. For example, the DNN can be used to select SMF and UPF(s) for a PDU session, and to select interface(s) between the data network and UPF (e.g., N6 interfaces) for a PDU session. Additionally, the DNN can be used to determine the mobile operator's policy to be applied to the PDU session.

[0095] The ATSSS function is a function that transmits data traffic through one or more accesses by utilizing both the aforementioned 3GPP access and / or Non-3GPP access between the terminal and the 5G core network. A typical example is when the 5G core network determines that there is insufficient user-plane resource between the terminal and the data network (DN) (180) or that the network's resource management capacity is overloaded; in this case, instead of transmitting data traffic through only one of the 5G access or Wi-Fi access, the ATSSS (Access Traffic Steering, Switching, Splitting) function enables both 5G access and Wi-Fi access to distribute and transmit the data.

[0096] FIG. 2 illustrates an ATSSS support structure in a wireless communication system according to one embodiment of the present disclosure.

[0097] Referring to FIG. 2, the UE (10) can connect to a mobile communication network, such as 3GPP Access (210), and a non-mobile communication network, such as Non-3GPP Access (220). The ATSSS function may include steering functionality and a steering mode.

[0098] Steering functionality can determine the transport protocol between the UPF of the transmitting device and the UPF of the receiving device. Steering functionality can be determined by which transport layer determines the steering, switching, and splitting of traffic. If the MPTCP (Multi Path TCP) (IETF RFC 8684) protocol located at a layer higher than the IP layer is used, the steering function may correspond to 'MPTCP functionality', and if it is determined at a layer lower than the IP layer, the steering function may correspond to 'ATSSS-LL (ATSSS-Lower Layer) functionality'. The UE may include MPTCP functionality (11) and ATSSS-LL functionality (12).

[0099] UEs and networks that support MPTCP functionality can communicate with MPTCP Proxy functionality (111) configured separately within the UPF (110). MPTCP functionality can only control TCP traffic that supports the MPTCP protocol. If ATSSS-LL functionality is supported, the UPF may not include a separate Proxy component and can control all types of TCP traffic.

[0100] Steering mode defines the method of steering, switching, and splitting data traffic.

[0101] In addition, the UPF (110), SMF (130), and PCF (140) according to the present disclosure may perform separate control operations for connecting the UE (10). These control operations will be further examined with reference to the drawings described later.

[0102] The UPF (110) according to the present disclosure may include an MPTCP proxy functionality (111) internally, as illustrated in the drawings.

[0103] The Performance Measurement Function (PMF) is a function that measures the network environment between the UE and the UPF, and can measure the round trip time (RTT) required for uplink and downlink, and whether 3GPP access and non-3GPP access are currently active. Based on the information provided by the PMF, the steering functionality and steering mode that the core network can support can be determined, which has an overall influence on the determination of parameters for N3 and N4 connections. The PMF can be included within the UPF (110) and the UE (10), respectively. The PMF included in the UPF can be referred to as the UPF-PMF (112), and the PMF included in the UE can be referred to as the UE-PMF (113).

[0104] By utilizing the ATSSS function described in Fig. 2, traffic transmission through multiple paths between the PDU Session Anchor UPF (110) and the UE (10) is possible as in Fig. 1.

[0105] FIG. 3 illustrates an example of a network structure and interface of an EPS (Evolved Packet System) / 5GS (5G system) interworking system according to one embodiment of the present disclosure.

[0106] The 5GS may include an NR base station (NG-RAN (radio access node) or gNB (evolved node B)) (204) for wireless access of a terminal (UE) (201b), an access and mobility management function (AMF) (205), and additionally, although not shown in FIG. 2, may include a session management function (SMF), a user plane function (UPF), a policy control function (PCF), a network slice selection function (NSSF), unified data management (UDM), a unified data repository (UDR), etc.

[0107] The EPS may include an E-UTRA base station (E-UTRAN (Evolved UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network), or eNB) (202) for wireless access of a terminal (UE) (201a), a mobility management entity (MME) (203), a serving gateway (SGW) (206), a packet data network gateway (PGW) (the PGW may be composed of PGW-U and PGW-C), a policy and charging rule function (PCRF), a home subscriber server (HSS), etc.

[0108] According to one embodiment, the AMF and MME may be Network Functions (NFs) that manage wireless network access and mobility for a terminal. The SMF, SGW, and PGW are NFs that manage sessions for a terminal, and the session information may include Quality of Service (QoS) information, charging information, and information regarding packet processing. Additionally, the UPF and PGW are NFs that process user plane traffic (e.g., User Plane traffic) and are controlled by the SMF and SGW. The PCF and PCRF may be NFs that manage operator policies (operator policy and / or PLMN policy) for providing services in a wireless communication system. Furthermore, the PCF may be divided into a PCF responsible for Access and Mobility (AM) policies and UE policies, and a PCF responsible for Session Management (SM) policies. The AM / UE policy-managing PCF and the SM policy-managing PCF may be logically or physically separated NFs, or may be a single logically or physically NF. The UDM and HSS may be NFs that store and manage the terminal's subscriber information (UE subscription). The UDR may be an NF or a database (DB) that stores and manages data. The UDR (212) may store the terminal's subscription information and provide the terminal's subscription information to the UDM. Additionally, the UDR (212) may store operator policy information and provide the operator policy information to the PCF. The NSSF may be an NF that performs the function of selecting network slice instances that service the terminal or determining the NSSAI (Network Slice Selection Assistance Information).

[0109] The above instance may refer to a state in which the NF exists in the form of software code and is capable of executing the functions of the NF by receiving physical and / or logical resources from a computing system (e.g., a specific computing system existing on a core network) to perform the functions of the NF. For example, an AMF Instance, an SMF Instance, an NSSF Instance, etc., may each refer to a state in which physical and / or logical resources are allocated from a specific computing system existing on a core network for the operation of the AMF, SMF, NSSF, etc. Therefore, the AMF Instance, SMF Instance, and NSSF Instance that use physical and / or logical resources allocated from a specific computing system existing on a network for the operation of the AMF, SMF, NSSF, etc., can perform the same operation as when physical AMF, SMF, or NSSF devices exist.

[0110] The UDM of the 5GS and the HSS of the EPS can be configured into a single combo node (referred to as UDM+HSS) (211). The UDM+HSS node (211) can store subscriber information of the terminal. The SMF of the 5GS and the PGW-C of the EPS can be configured into a single combo node (referred to as SMF+PGW-C) (208). The PCF of the 5GS and the Policy Control and Charging Rules Function (PCRF) of the EPS can be configured into a single combo node (referred to as PCF+PCRF). The UPF of the 5GS and the PGW-U of the EPS can be configured into a single combo node (referred to as UPF+PGW-U) (207). The terminal can use EPS network services by connecting to the MME of the EPS through an E-UTRA base station. Additionally, the terminal can use 5GS network services by connecting to the AMF of the 5GS through an NR base station. In FIG. 2, the same reference numeral was used for the terminal connected to the EPS and the terminal connected to the 5GS. This is to indicate that the terminal can be connected to the EPS and can be connected to the 5GS.

[0111] In this way, a single NF or network entity can simultaneously support different network systems, and such NF, network node, or network entity may be referred to as the previously described combo node, combo NF, combined node, combined NF, interworking node, interworking NF, etc. Furthermore, the function of the NF exemplified as the combo node above may be implemented through interworking between two or more network entities. In addition, for the convenience of illustration and explanation, NFs that simultaneously support different network systems may be indicated using the "+" symbol or the " / " symbol. For example, if SMF and PGW-C are composed of a single combo node, it may be expressed as PGW-C / SMF, PGW-C+SMF, SMF / PGW-C, or SMF+PGW-C.

[0112] Terminals (201a, 201b) can establish a session by connecting to a data network (e.g., a network providing internet services) through a 5GS or EPS system. 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). For distinguishing data networks, a DNN can be used in 5GS, and an APN can be used in EPS. The DNN and APN can be used to determine NFs related to the user plane, interfaces between NFs, operator policies, etc., when the terminal establishes a session with the network system. The DNN and APN can be understood as equivalent information and can convey the same information. The DNN can be used, for example, to select SMF and UPF(s) for a PDU session, and can be used to select interface(s) between the data network and UPF (e.g., N6 interface) for a PDU session. In addition, the above DNN can be used to determine the mobile operator's policy to be applied to PDU sessions.

[0113] In the following embodiments, for convenience of explanation, the names of combo nodes such as UDM+HSS nodes, PCF+PCRF nodes, SMF+PGW-C nodes, and UPF+PGW-C nodes will be described without the "node" designation. Additionally, in the following embodiments, the definition of a message defined in one embodiment may be applied with the same meaning in other embodiments using the same message.

[0114] The PCF can be divided into a Session Management-Policy Control Function (SM-PCF) (not shown) responsible for Session Management Policy (SM Policy) and a Terminal-Policy Control Function (UE-PCF) (not shown) responsible for Mobility Management Policy (AM Policy) and / or Terminal Policy (UE Policy). The SM-PCF can be connected to the SMF via the N7 interface, but cannot be connected to the AMF (205). In other words, the SM-PCF cannot support the N15 interface. The UE-PCF can be connected to the AMF (205) via the N15 interface, but cannot be connected to the SMF. In other words, the UE-PCF cannot support the N7 interface. The SM-PCF and the UE-PCF may be located in a single device or a single PCF physically and / or logically, but may be distinguished as different PCF instances.

[0115] The UE Policy provided by PCF to the UE may include at least one of the Access Network Discovery & Selection Policy (ANDSP), UE Route Selection Policy (URSP), V2X (Vehicle-to-everything) Policy, or ProSeP (ProSe Policy).

[0116] Access Network Discovery & Selection Policy (ANDSP): Contains policy information required when a terminal selects a non-3GPP access network.

[0117] UE Route Selection Policy (URSP): Contains policy information necessary to route traffic exiting the terminal.

[0118] V2X Policy (V2XP): Includes policy information that provides configuration parameters necessary for a terminal to perform V2X communication.

[0119] ProSe Policy (ProSeP): Includes policy information that provides configuration parameters necessary for a terminal to perform ProSe Direct Discovery, ProSe Direct Communication, ProSe UE-to-Network Relay, and Remote UE communication.

[0120] Referring again to FIG. 3a, it may be an example of a non-roaming architecture of a 5GS and EPC / E-UTRAN interworking system. Additionally, FIG. 3b may be an example of a local breakout roaming architecture of a 5GS and EPC / E-UTRAN interworking system, and FIG. 3c may be an example of a home-routed roaming architecture of a 5GS and EPC / E-UTRAN interworking system. The above description may be explained based on FIG. 3a, but is not limited to the description of FIG. 3a. Therefore, the above description may be applied likewise to FIGs. 3b through 3c.

[0121] Meanwhile, FIGS. 3d to 3f may respectively illustrate examples of a non-roaming architecture, a local breakout roaming architecture, and a home-routed roaming architecture in a 5GC and EPC / E-UTRAN interworking system via 3GPP access. Additionally, FIGS. 3g to 3i may respectively illustrate examples of a non-roaming architecture, a local breakout roaming architecture, and a home-routed roaming architecture in an ePDG (Enhanced Packet Data Gateway) / EPC and 5GS interworking system. It goes without saying that the above description may be applied in the same way to FIGS. 3d to 3i. FIG. 4 illustrates various forms of a Multi Access (MA) PDU Session according to an embodiment of the present disclosure.

[0122] Referring to Fig. 4, the MA PDU Session can be extended to Dual Steer.

[0123] A UE can be connected to one or more core networks, and each core network can be connected through one or more access networks.

[0124] A single path through which a UE connects to a core network via an access network can be referred to as an access path.

[0125] A UE can use an MA PDU Session composed of one or more access paths. PDU Sessions connected through each access path can be managed as a single MA PDU Session by using the same PDU Session ID.

[0126] There may be direct or indirect connections between different core networks. For example, the connection may be a roaming relationship, a relationship that supports interworking like the relationship between AMF and MME, or a Combo Node like SMF+PGW-C.

[0127] The types of different access networks that can be connected to a single core network may be the same or different. For example, the Access Type for the first access network and the second access network that can be connected to the first core network may both be 3GPP access or Non-3GPP access. Or, one of the Access Types may be 3GPP access and the other may be Non-3GPP access.

[0128] As another example, there may be two or more access networks that can be connected to a single core network. For example, access networks that can be connected to a single core network may include three 3GPP access networks, or two 3GPP access networks and one non-3GPP access network.

[0129] In addition, the types of communication technologies used by different access networks that can be connected to a single core network may be the same or different. For example, the RAT Type of the first access network that can be connected to the first core network is NG-RAN, and the RAT Type of the second access network is NG-RAT (low earth orbit, LEO), so the Access Types are both 3GPP access, but the RAT Types may be different.

[0130] Referring to FIG. 4 (a), there may be cases where an MA PDU Session connected only to the first core network is allowed. In this case, the UE can use the MA PDU Session through the first access network and / or the second access network to the first core network. For example, the UE can use an MA PDU Session connected to the 5G Core Network (5GC) through NG-RAN (3GPP Access) and / or N3IWF (Non-3GPP Access). In this case, even if the UE is registered with both NG-RAN and N3IWF, it may be allowed to use an MA PDU Session using only one of the ANs depending on the steering mode.

[0131] Referring to FIG. 4(b), there may be cases where an MA PDU Session connected only to the second core network is not allowed. In this case, the UE may not be allowed to have an MA PDU Session connected only to the third access network, only to the fourth access network, or to both the third access network and the fourth access network. For example, the UE cannot use an MA PDU Session that has a connection only to the 4G Core Network (EPC) via E-UTRAN (3GPP Access) and / or ePDG (Non-3GPP Access). In this case, the UE may only be allowed to use a PDN Connection (or PDU Session) with different PDU Session IDs for E-UTRAN and ePDG, respectively. For convenience, FIG. 4 explains the premise that an MA PDU Session connected only to the EPC is not allowed, while an MA PDU Session connected only to the 5GC is allowed. However, it is not limited to this.

[0132] Referring to Fig. 4(c), there may be cases where an MA PDU Session connected to both the first core network and the second core network is allowed. In this case, the UE can use an MA PDU Session that is connected to the first core network via the first access network and to the second core network via the fourth access network. For example, the UE can use an MA PDU Session that is connected to 5GC via NG-RAN (3GPP Access) and to EPC via ePDG (Non-3GPP Access).

[0133] The UE and / or network may use an MA PDU Session of the form of Fig. 4(a), and then, depending on the state of the UE and the network, change some access paths to connections of the second core network to use an MA PDU Session of the form of Fig. 4(c). For example, the UE may use an MA PDU Session composed of NG-RAN connections and N3IWF connections, but if the access coverage of NG-RAN is poor, it may change the NG-RAN connections to E-UTRAN connections and ultimately use an MA PDU Session composed of E-UTRAN and N3IWF connections. As another example, the UE may use an MA PDU Session composed of NG-RAN connections and N3IWF connections, but if the access coverage of N3IWF is poor, it may change the N3IWF connections to ePDG connections and ultimately use an MA PDU Session composed of NG-RAN and ePDG connections.

[0134] However, the UE cannot change to using an MA PDU Session of the form of Fig. 4(b). Therefore, when a procedure to change an MA PDU Session of the form of Fig. 4(a) to an MA PDU Session of the form of Fig. 4(c) is in progress, or when a procedure to establish a new MA PDU Session of the form of Fig. 4(c) is in progress, the UE and / or the network may need to perform an action to prevent the procedure from proceeding to an MA PDU Session of the form of Fig. 4(b). For example, if the UE uses an MA PDU Session through NG-RAN and N3IWF and then changes the NG-RAN connection to E-UTRAN, an action may need to be performed to allow the use of the MA PDU Session only when the N3IWF connection can be maintained. For example, if a UE is deregistered from N3IWF, both the MA PDU session via N3IWF and the MA PDU session via E-UTRAN may need to be released. As another example, if a UE requests an MA PDU session via E-UTRAN and establishes a PDN Connection assigned a specific PDU Session ID, the UE cannot request a PDN Connection with the same PDU Session ID as an MA PDU session via ePDG. Furthermore, the network cannot activate an EPS Bearer (or user-plane resource) for an MA PDU session via ePDG.In addition, if the UE does not request a PDU Session as an MA PDU Session via N3IWF after the network has accepted a PDN Connection request as an MA PDU Session via E-UTRAN, the network may activate a user-plane resource for the MA PDU Session via N3IWF or release the UE's MA PDU Session via E-UTRAN.

[0135] The network may decide whether to provide the ATSSS Rule to the UE via the corresponding E-UTRAN or ePDG connection (first access path) through which the MA PDU Session request was transmitted when the UE requests a new MA PDU Session via E-UTRAN or ePDG, or to provide it to the UE via the second access path through the N3IWF or NG-RAN connection corresponding to the 5GC access path when the UE requests the MA PDU Session or when the network activates the user-plane resource of the MA PDU Session. The method of determining the access path to provide the ATSSS Rule may have a technical effect of preventing the UE or the network from performing the action of creating a 5GC access path, or preventing the transmission of traffic using the MA PDU Session from starting before that, by ensuring that only traffic with steering mode or steering functionality applied exists where the UE only needs to use the EPC access path.

[0136] FIG. 5 illustrates an example of a 5GS / EPS interworking system according to one embodiment of the present disclosure providing an ATSSS rule to a UE. Specifically, in a hybrid network supporting both 5GS and EPS (EPS-5GS interworking supporting network system), when a UE intends to use an MA PDU Session where 3GPP access is connected to 5GC and Non-3GPP access is connected to EPC, a method of providing an ATSSS rule to a UE in a 5GS-EPS interworking network can be described.

[0137] 1. A UE may send a PDN Connection request message to a network via an ePDG, which is a non-3GPP access network. For example, the PDN Connection request message may be sent in various forms, such as Initial Initiation, Initial Attach, IKEv2 Authentication and Tunnel Setup, or PDN Connectivity Request. The PDN Connection request message may include information indicating that the UE's PDN Connection request is a request for an MA PDU session. For example, it may include an “MA PDU Request” indicator or an “ATSSS Request” indicator. The UE may provide information required for the use of ATSSS functions (or the use of an MA PDU session) in the PDN Connection request message. For example, it may include information on the UE's ATSSS capabilities. The UE may provide the session identifier for the requested PDN Connection. For example, it may include a PDU Session ID.

[0138] 2. The ePDG can forward the UE's request by selecting an SMF+PGW-C suitable for the UE's request. For example, the UE's request message can be transmitted in various forms, such as a Create Session Request. The UE's request message may include part or all of the request information received from the UE in Step 1, and may include at least one of information indicating that the UE's PDN Connection request is a request for an MA PDU session, information required for the use of the ATSSS function, and a session identifier. In one embodiment, when forwarding the request received from the UE, the ePDG may use a method of forwarding the entire UE's request information in a container form as is, without understanding or editing it. In this case, the ePDG may forward the information by including it in a PCO (Protocol Configuration Options) or APCO (Additional Protocol Configuration Options). Additionally, the UE's request message may further include information regarding the current access (e.g., RAT Type) as information that the ePDG can directly provide to the SMF+PGW-C. The value of RAT Type can be set to non-3GPP IP access. For example, non-3GPP IP access can represent the radio access technology provided by the ePDG. When selecting SMF+PGW-C, the ePDG may consider the ATSSS capabilities of the UE and / or network, and whether it supports MA PDU Sessions connecting non-3GPP access to the EPC.

[0139] 3. Based on the request information received from the ePDG in Step 2, the SMF+PGW-C may proceed with the judgment and execution of actions necessary for providing ATSSS functions and establishing and managing MA PDU Sessions. For example, the SMF+PGW-C may determine that a UE has requested the establishment of a PDN Connection as an MA PDU Session connecting Non-3GPP access to the EPC. The SMF+PGW-C may communicate with the HSS+UDM to determine whether to accept the request, etc., based on session-related subscriber information regarding the UE's MA PDU Session request. The SMF+PGW-C may communicate with the PCF to receive policies (e.g., AM policy, SM policy, UE policy, etc.) necessary for the UE to use an MA PDU Session connecting Non-3GPP access to the EPC, and determine the QoS settings for the session and rules and information related to ATSSS functions to be provided to the UPF and / or the UE. Examples of rules and information related to session QoS settings and ATSSS functions to be provided to UPF and / or UE include ATSSS Rules provided to UE. Examples of ATSSS Rules include [Table 1] below.

[0140]

[0141] SMF+PGW-C can determine which access to use when transmitting ATSSS Rules to the UE, and may refer to at least one of the following information:

[0142] 1) If there is a session identifier (e.g., PDU Session ID) among the information received in Step 2, SMF+PGW-C may refer to whether information about the session indicated by the session identifier (e.g., SM Context information) exists in SMF+PGW-C. At this time, whether SM Context information exists may have significance as information indicating that the corresponding PDU Session (or PDN Connection) is managed by SMF+PGW-C and that the session already exists. Therefore, even if SM Context is not stored, SMF+PGW-C may refer to at least one of the information in Table 1 if it can determine that the session identified by the PDU Session ID currently exists between the UE and SMF+PGW-C.

[0143] 2) SMF+PGW-C can refer to whether the ATSSS rule includes a rule associated with the access currently being used by the UE. For example, if the steering mode in the ATSSS rule corresponds to a rule that provides a traffic splitting function such as “Load-Balancing” (if possible, SMF+PGW-C can also refer to whether the splitting ratio corresponds to 100:0), SMF+PGW-C can refer to this to determine that even if the UE receives the ATSSS rule as access corresponding to the EPC connection, it cannot properly use the ATSSS function without establishing access corresponding to the 5GC connection.

[0144] 3) SMF+PGW-C may refer to at least one of the information in Table 1 if there are restrictions or settings regarding the use of MA PDU Sessions, the ATSSS function of the UE and / or network. For example, if there are restrictions or settings where the UE and the network cannot use MA PDU Sessions with only an EPC connection, SMF+PGW-C may refer to this information in determining whether it can control problems that may occur when the UE receives access corresponding to the EPC connection (e.g., problems using MA PDU Sessions without establishing a 5GC connection).

[0145] 4) SMF+PGW-C may determine the access to provide the ATSSS Rule to the UE by referring to at least one of the information in 1, 2, and 3 above. For example, SMF+PGW-C may determine that, if it receives a session identifier (e.g., PDU Session ID) in Step 2, there is no SM Context for the PDN Connection or PDU Session corresponding to the received session identifier, or that the session does not exist. Additionally, if SMF+PGW-C determines that the current UE and network are restricted from using the MA PDU Session with only EPC access, SMF+PGW-C may first provide the ATSSS Rule to the UE through the EPC access used to transmit the request message for establishing the PDN Connection as the MA PDU Session in Step 2. And if the 5GC connection for this MA PDU session is not established or activated for a certain period of time, SMF+PGW-C may decide to initiate a procedure to release the EPC connection of the MA PDU Session, release or disable the bearer (or user-plane resource) used for the EPC connection, or request that the ATSSS Rule provided to the UE no longer be used.

[0146] 3a. Meanwhile, if there is no SM context for the received PDU session ID or if the ATSSS rule is associated with an access (e.g., non-3GPP EPC access / ePDG), the SMF+PGW-C may first transmit the ATSSS rule through the aforementioned access and, if no PDU session is requested through the 5GC access (e.g., 3GPP 5GC access / NG-RAN) for a certain period of time, determine a deletion request. At this time, the procedures of steps 5 and 6 below may be performed.

[0147] 4. SMF+PGW-C may decide to accept a request to establish a PDN Connection as an MA PDU Session of Step 2. Additionally, based on the decision in Step 3 (including Step 3a), SMF+PGW-C may monitor for a certain period of time whether a request to establish a 5GC connection for this MA PDU session or a request for the creation, activation, or reactivation of a user-plane resource occurs. To do this, SMF+PGW-C may start a timer.

[0148] 5. SMF+PGW-C may send a response message to the ePDG regarding the request to establish a PDN Connection as an MA PDU Session in Step 2. The response message may be sent in various forms, such as Create Session Response. The response message may include information accepting the establishment of a PDN Connection as an MA PDU Session. The information included in the response message may include indicators in the form of “MA PDU Accepted”. Additionally, the response message may include an ATSSS Rule based on the determination in Step 3, 3a. SMF+PGW-C may allow the information transmitted in the response message of Step 5 to be delivered in a container form as is, without the ePDG understanding or editing it, and in this case, may provide the information included in the response message to the PCO or APCO.

[0149] 6. The ePDG may send part or all of the response message to the UE regarding the request to establish a PDN Connection as an MA PDU Session received in Step 5. For example, the response message may be sent in various forms such as Connection configuration, Direct Transfer, IKEv2 IP address configuration, or PDN Connectivity Response. In cases where there are restrictions and settings preventing the use of an MA PDU Session using only an EPC connection, the UE may not use the MA PDU session until a 5GC connection is established, even if it has received an ATSSS Rule.

[0150] 7. SMF+PGW-C may observe whether a 5GC connection for an MA PDU session is not established or activated during the time set by the timer activated in Step 4. If a 5GC connection for an MA PDU session is not established or activated until the time set by the timer is reached, SMF+PGW-C may initiate a procedure to release the PDN Connection as the MA PDU Session accepted in Step 5, release or deactivate the bearer of the PDN Connection, or prevent the use of the ATSSS Rule provided to the UE. For example, SMF+PGW-C may initiate a Resource Application Deactivation procedure. The Resource Application Deactivation procedure may be a procedure to delete the PDN Connection bearer. The timer used in Steps 4 and 7 may include a “PDN connection inactivity timer” or a “PDU Session inactivity timer”. At this time, SMF+PGW-C can observe the inactivity (inactive) state of the PDN Connection accepted in Step 5, and at the same time observe the absence or inactivity state of the 5GC connection. SMF+PGW-C can extend the timer one or more times before performing Step 8.The technical feature of the operation in Step 7 may be that, unlike the operation in Step 7 which generally involves monitoring the active state of a session and performing management actions such as changing the active state of the session's user-plane or modifying or releasing the session based on the monitoring results, it involves monitoring the active state of a session's access path (here, access connected to the 5GC) and performing management actions such as changing the state of another access path of the same session (here, access connected to the EPC accepted in Step 5) or modifying or releasing the session based on these results. In particular, using a method to monitor the inactivity of a session may correspond to a method in which the SMF+PGW-C can indirectly detect state information in the UE's 5GC by monitoring the state of the user plane when it cannot directly receive the registration status or connection status of the UE's 5GC from the MME. The above-described method may be applicable in cases where the UE is connected to the EPC first, rather than in cases where the UE is connected to the 5GC first in the 5GS-EPS interworking network and then moves to the EPC (handover or mobility).

[0151] 8. SMF+PGW-C may request the deletion of a bearer of a PDN Connection in accordance with the initiation of Step 7. For example, the request message may be transmitted in various forms such as a Delete Bearer Request, an IKEv2 INFORMATIONAL Request (including a Delete payload), or an IKEv2 Tunnel Release Trigger. The request message for the deletion of a bearer of a PDN Connection may include information indicating that the deletion of the bearer is requested because the 5GC connection of the MA PDU session has not been established. For example, information indicating that the deletion of the bearer is requested may be provided in various forms such as “5GC leg of MA PDU Session has not initiated”, “PDN connection inactivity timer expiry”, or “PDU session inactivity timer expiry”. Even though the UE has transmitted and received traffic through the PDN Connection, if it receives information such as “PDN connection inactivity timer expiry” or “PDU session inactivity timer expiry” from the SMF+PGW-C, it can be determined that this information was received because the 5GC connection of the MA PDU session was not established or the active state was not maintained.

[0152] 9. Based on the bearer deletion request received in step 8, the UE may consider whether to request the establishment of a 5GC connection for the MA PDU session. If the UE does not intend to establish a 5GC connection, it may respond to the bearer deletion request.

[0153] 10. The UE may send a response message to the bearer deletion request to the ePDG, and the ePDG may send the received response message to the MSF+PGW-C.

[0154] 11-14. A bearer deletion operation may be performed.

[0155] An example of providing an ATSSS rule to a UE in a 5GS / EPS interworking system according to one embodiment of the present disclosure is illustrated. More specifically, in a hybrid network supporting both 5GS and EPS (EPS-5GS interworking supporting network system), when a UE intends to use an MA PDU Session where 3GPP access is connected to 5GC and Non-3GPP access is connected to EPC, a method of providing an ATSSS rule to a UE in a 5GS-EPS interworking network may be described.

[0156] FIG. 6 illustrates an example in which, in steps 3 and 3a of FIG. 5, SMF+PGW-C performs the judgment and actions necessary for providing the ATSSS function and establishing and managing the MA PDU Session based on the request information received from ePDG in step 2, and a judgment is made regarding a situation different from that in FIG. 5. Therefore, content that overlaps with FIG. 5 may be omitted.

[0157] 1. A UE may send a PDN Connection request message to a network via an ePDG, which is a non-3GPP access network. For example, the PDN Connection request message may be sent in various forms such as Initial Initiation, Initial Attach, IKEv2 Authentication and Tunnel Setup, or PDN Connectivity Request. The PDN Connection request message may be provided with information indicating that the UE's PDN Connection request is a request for an MA PDU session (e.g., an “MA PDU Request” indicator, an “ATSSS Request” indicator). The UE may provide information required for the use of ATSSS capabilities (i.e., the use of the MA PDU session) in the PDN Connection request message (e.g., information on the UE's ATSSS capabilities). The UE may provide a session identifier for the requested PDN Connection, such as a PDU Session ID.

[0158] 2. The ePDG can forward the UE's request by selecting an SMF+PGW-C suitable for the UE's request. The UE's request message may be transmitted in various forms, such as a Create Session Request. The UE's request message may include part or all of the request information received from the UE in Step 1. For example, it may include at least one of information indicating that the UE's PDN Connection request is a request for an MA PDU session, information required for the use of the ATSSS function, or a session identifier. In forwarding the request received from the UE, the ePDG may use a method of forwarding the entire UE's request information in a container form as is, without understanding or editing it. In this case, the information may be included in the PCO or APCO and forwarded. Additionally, the UE's request message may include information regarding the current access (e.g., RAT Type) as information that the ePDG can directly provide to the SMF+PGW-C. For example, the value of the RAT Type may be set to non-3GPP IP access. non-3GPP IP access may represent the radio access technology provided by the ePDG. When selecting SMF+PGW-C, ePDG may consider whether it supports the ATSSS capabilities of the UE and / or network, and / or MA PDU Sessions connecting non-3GPP access to the EPC.

[0159] 3. Based on the request information received from the ePDG in Step 2, SMF+PGW-C may proceed with the judgment and execution of actions necessary for providing ATSSS functions and establishing and managing MA PDU Sessions. For example, SMF+PGW-C may determine that a UE has requested the establishment of a PDN Connection as an MA PDU Session connecting Non-3GPP access to the EPC. SMF+PGW-C may communicate with HSS+UDM to obtain session-related subscriber information regarding this MA PDU Session request from the UE and determine whether to accept the request. SMF+PGW-C may communicate with PCF to determine the QoS settings of the session and rules and information related to ATSSS functions to be provided to the UPF and / or the UE, based on policies (e.g., AM policy, SM policy, or UE policy) necessary for the UE to use the MA PDU Session connecting Non-3GPP access to the EPC. Examples of rules and information related to the session's QoS settings and the ATSSS function to be provided to the UPF and / or the UE may include ATSSS Rules provided to the UE. Examples of ATSSS Rules may correspond to [Table 1] described above. SMF+PGW-C may determine which access to use when delivering ATSSS Rules to the UE, and may refer to at least one of the following information when making this determination:

[0160] 1) If there is a session identifier (e.g., PDU Session ID) among the information received in Step 2, SMF+PGW-C can refer to whether information about the session indicated by the session identifier (e.g., SM Context information) exists in SMF+PGW-C. In this case, whether SM Context information exists can be meaningful as information indicating that the corresponding PDU Session (or PDN Connection) is managed by SMF+PGW-C and that the session already exists. Therefore, even if SM Context is not stored, SMF+PGW-C can refer to whether information about the session indicated by the identifier (e.g., SM Context information) exists in SMF+PGW-C if it can determine that the session identified by the PDU Session ID exists between the current UE and SMF+PGW-C.

[0161] 2) SMF+PGW-C can refer to whether the ATSSS rule includes a rule associated with the access currently being used by the UE. For example, if the steering mode in the ATSSS rule corresponds to a rule that provides a traffic splitting function such as “Load-Balancing” (and if possible, also refer to whether the splitting ratio corresponds to 100:0), SMF+PGW-C can refer to this to determine that even if the UE receives the ATSSS rule as access corresponding to the EPC connection, it cannot properly use the ATSSS function without establishing access corresponding to the 5GC connection.

[0162] 3) SMF+PGW-C may refer to at least one of the information in Table 1 if there are restrictions or settings regarding the use of MA PDU Sessions, the ATSSS function of the UE and / or network. For example, if there are restrictions or settings where the UE and the network cannot use MA PDU Sessions with only an EPC connection, SMF+PGW-C may refer to this information in determining whether it is possible to control problems that may occur when the UE receives access corresponding to the EPC connection (e.g., problems of using MA PDU Sessions without establishing a 5GC connection).

[0163] 4) SMF+PGW-C may determine the access to provide the ATSSS Rule to the UE by referring to at least one of the information in 1, 2, and 3 above. For example, if SMF+PGW-C receives a session identifier (e.g., PDU Session ID) in Step 2 and determines that an SM Context of a PDN Connection or PDU Session corresponding to the received session identifier exists, or that the session exists, SMF+PGW-C may determine to provide the ATSSS Rule to the UE through the EPC access used to transmit the request message for establishing a PDN Connection as the MA PDU Session in Step 2. If there are no changes compared to the ATSSS Rule previously provided to the UE, SMF+PGW-C may omit providing the ATSSS Rule. Additionally, if the 5GC access of the MA PDU session is disabled, SMF+PGW-C may initiate an activation or reactivation procedure. Step 4 and / or Step 5 may be performed.

[0164] 5) SMF+PGW-C may determine access to provide the ATSSS Rule to the UE by referring to at least one of the information in 1, 2, and 3 above. For example, if SMF+PGW-C receives a session identifier (e.g., PDU Session ID) in Step 2 and determines that an SM Context of a PDN Connection or PDU Session corresponding to the received session identifier exists, or that the session exists, SMF+PGW-C may determine to provide the ATSSS Rule to the UE through 5GC access of this MA PDU Session. If there are no changes compared to the ATSSS Rule previously provided to the UE, SMF+PGW-C may omit providing the ATSSS Rule. Additionally, if the 5GC access of the MA PDU session is disabled, SMF+PGW-C may initiate an activation or reactivation procedure. At least one of Steps 6 through 9 may be performed.

[0165] 6) SMF+PGW-C may determine the access to provide the ATSSS Rule to the UE by referring to at least one of the information in 1, 2, and 3 above. For example, if SMF+PGW-C receives a session identifier (e.g., PDU Session ID) in Step 2 and determines that an SM Context of a PDN Connection or PDU Session corresponding to the received session identifier exists, or that the session exists, SMF+PGW-C may determine to provide the ATSSS Rule to the UE through the 5GC access used in the connection request when the UE requests a connection to the 5GC access of this MA PDU Session. If there are no changes compared to the ATSSS Rule previously provided to the UE, SMF+PGW-C may omit providing the ATSSS Rule. Additionally, if the 5GC access of the MA PDU session is disabled, SMF+PGW-C may initiate an activation or reactivation procedure. At least one of Steps 10 through 14 may be performed.

[0166] 3a. Meanwhile, if an ATSSS rule exists for an EPS bearer / QoS flow associated with a received PDU session ID and / or access (e.g., non-3GPP EPC access / ePDG), the SMF+PGW-C may decide to transmit the ATSSS rule through the access (e.g., non-3GPP EPC access / ePDG). In this case, the procedures of steps 4 and 5 below may be performed.

[0167] 4. SMF+PGW-C may decide to accept the request to establish a PDN Connection as an MA PDU Session of Step 2. SMF+PGW-C may send a response message to the ePDG regarding the request to establish a PDN Connection as an MA PDU Session of Step 2. The response message may be sent in various forms, such as Create Session Response. The response message may include information accepting the establishment of a PDN Connection as an MA PDU Session. The information included in the response message may be an indicator in the form of “MA PDU Accepted”. Additionally, the response message may include an ATSSS Rule based on the decision of Step 3, 3a. SMF+PGW-C may allow the information transmitted in the response message of Step 4 to be delivered in a container form as is, without the ePDG understanding or editing it, and in this case, may provide the information included in the response message to the PCO or APCO.

[0168] 5. The ePDG may send part or all of the response message to the UE regarding the request to establish a PDN Connection as an MA PDU Session received in Step 4. For example, the response message may be sent in various forms such as Connection configuration, Direct Transfer, IKEv2 IP address configuration, or PDN Connectivity Response. If there are restrictions and settings preventing the use of an MA PDU Session using only an EPC connection, the UE may not use the MA PDU session until a 5GC connection is established, even if it has received an ATSSS Rule.

[0169] 3b. If an SM context exists for an EPS bearer / QoS flow associated with a received PDU session ID and / or another access (e.g., 3GPP 5GC access / NG-RAN), the SMF+PGW-C may decide to transmit an ATSSS rule through the other access by triggering the reactivation of the user plane resource through the 5GC segment of the MA PDU session. At this time, the procedures of steps 6 through 9 below may be performed.

[0170] 6. SMF+PGW-C may decide to accept the request to establish a PDN Connection as an MA PDU Session of Step 2. SMF+PGW-C may send a response message to the ePDG regarding the request to establish a PDN Connection as an MA PDU Session of Step 2. For example, the response message may be sent in various forms of a Create Session Response. The response message may contain information accepting the establishment of a PDN Connection as an MA PDU Session. The information included in the response message may be an indicator in the form of “MA PDU Accepted”. Additionally, the response message may include an ATSSS Rule based on the decision of Step 3, 3a. SMF+PGW-C may allow the information transmitted in the response message of Step 4 to be delivered in a container form as is, without the ePDG understanding or editing it, and in this case, may provide the information included in the response message to the PCO or APCO.

[0171] 7. The ePDG may send part or all of the response message to the UE in response to the request to establish a PDN Connection as an MA PDU Session received in Step 6. For example, the response message may be sent in various forms such as Connection configuration, Direct Transfer, IKEv2 IP address configuration, or PDN Connectivity Response.

[0172] 8. SMF+PGW-C can initiate an activation or reactivation procedure if 5GC access of the MA PDU session is disabled.

[0173] 9. SMF+PGW-C can provide ATSSS Rules to the UE through 5GC access of the MA PDU session. For example, ATSSS Rules can be provided to the UE in various forms, such as PDU Session Modification Commands. Here, it may be assumed that there are restrictions or settings where the RAT Types for EPC access and 5GC access cannot be the same when the UE and the network use MA PDU sessions. Determining the active status of a 5GC connection, taking into account the RAT Type, may also apply to all other embodiments described in this disclosure. For example, SMF+PGW-C can provide ATSSS rules to the UE through AMF and NG-RAN.

[0174] 3c. If an SM context exists for an EPS bearer / QoS flow associated with a received PDU session ID and / or another access (here, 3GPP 5GC access / NG-RAN), when a UE requests a 5GC segment of an MA PDU session, SMF+PGW-C may decide to transmit an ATSSS rule through the other access. In this case, the procedures of steps 10 through 14 below may be performed.

[0175] 10. SMF+PGW-C may decide to accept the request to establish a PDN Connection as an MA PDU Session of Step 2. SMF+PGW-C may send a response message to the ePDG regarding the request to establish a PDN Connection as an MA PDU Session of Step 2. For example, the response message may be sent in various forms, such as Create Session Response. The response message may include information accepting the establishment of a PDN Connection as an MA PDU Session. The information included in the response message may be an indicator in the form of “MA PDU Accepted”. Additionally, the response message may include an ATSSS Rule based on the decision of Step 3, 3a. SMF+PGW-C may allow the information transmitted in the response message of Step 4 to be delivered in a container form as is, without the ePDG understanding or editing it, and in this case, may provide the information included in the response message to the PCO or APCO.

[0176] 11. The ePDG may send part or all of the response message to the UE in response to the request to establish a PDN Connection as an MA PDU Session received in step 10. For example, the response message may be sent in various forms such as Connection configuration, Direct Transfer, IKEv2 IP address configuration, or PDN Connectivity Response.

[0177] 12. In response to the acceptance of the establishment of a PDN Connection as an MA PDU Session received in Step 11, the UE may consider whether to request the establishment of a 5GC connection for the MA PDU Session. If 5GC access for the MA PDU Session is disabled, the UE may initiate an activation or reactivation procedure.

[0178] 13. The UE may request to establish or modify a PDU session for the 5GC connection of the MA PDU session accepted in Step 11. For example, the request to establish or modify a PDU session may be provided in various forms, such as a PDU Session Establishment Request or a PDU Session Modification Request. The request to establish or modify a PDU session may be transmitted to SMF+PGW-C via NG-RAN and AMF.

[0179] 14. SMF+PGW_C may provide an ATSSS rule to the UE via the 5GC connection in response to a request to establish or modify a PDU session for the 5GC connection of the MA PDU session of Step 13. For example, it may be provided in various forms such as a PDU Session Establishment Response or a PDU Session Modification Response.

[0180] FIG. 7 illustrates an example of providing an ATSSS rule to a UE in a 5GS / EPS interworking system according to one embodiment of the present disclosure. More specifically, a method of providing an ATSSS rule to a UE in a 5GS-EPS interworking network is described when a UE in a hybrid network supporting both 5GS and EPS (EPS-5GS interworking supporting network system) intends to use an MA PDU Session where 3GPP access is connected to the EPC and Non-3GPP access is connected to the 5GC.

[0181] FIG. 7 illustrates a method in which a UE and a network negotiate the capability to receive or transmit ATSSS rules through an EPC access path when the 3GPP access is an EPC access, and the negotiation result can be additionally considered when selecting the access to provide ATSSS rules. Therefore, descriptions that overlap with FIG. 5 and 6 may be omitted.

[0182] 1. A UE may send a PDN Connection request message to a network via an E-UTRAN or MME, which is a non-3GPP access network. For example, the PDN Connection request message may be sent in various forms, such as Initial Initiation, Initial Attach, IKEv2 Authentication and Tunnel Setup, or PDN Connectivity Request. The PDN Connection request message may be provided with information indicating that the UE's PDN Connection request is a request for an MA PDU session (e.g., an “MA PDU Request” indicator or an “ATSSS Request” indicator). The UE may include information necessary for the use of ATSSS capabilities (e.g., the use of an MA PDU session) in the PDN Connection request message (e.g., information on the UE's ATSSS capabilities). The UE may provide the session identifier of the requested PDN Connection (e.g., PDU Session ID). The UE may provide information regarding the UE's capability to receive or send ATSSS rules through the EPC access path. For example, information about the UE's capabilities may include indicators such as “ATSSS Rule Provisioning via EPC 3GPP access Support” or “ATSSS Rule Provisioning via EPC Support”. When transmitting a PDN Connection request, the UE may use a method of transmitting the UE's request information in a container form as is, without other entities (e.g., MME, SGW) other than SMF+PGW-C understanding or editing the entire information.In this case, the UE can include the UE's request information in the PCO or ePCO (Extended Protocol Configuration Options) and transmit it.

[0183] 2. The MME may select an SMF+PGW-C suitable for the UE's request and forward the UE's request. For example, the request message may be transmitted in various forms, such as a Create Session Request. The request message may include some or all of the request information received from the UE in Step 1. For example, the request message may include at least one of the following: information indicating that the UE's PDN Connection request is a request for an MA PDU session; information required for the use of the ATSSS function; a session identifier; and information regarding the UE's capability to receive or transmit ATSSS rules through the EPC access path. Additionally, the request message may include information regarding the current access (e.g., RAT Type) as information that the MME can directly provide to the SMF+PGW-C. In selecting the SMF+PGW-C, the MME may consider the ATSSS capabilities of the UE and / or network and whether it supports an MA PDU Session connecting 3GPP access to the EPC.

[0184] 3. Based on the request information received from the MME in Step 2, the SMF+PGW-C may proceed with the judgment and execution of actions necessary for providing ATSSS functions and establishing and managing MA PDU sessions. For example, the SMF+PGW-C may determine that the UE has requested the establishment of a PDN Connection as an MA PDU Session connecting 3GPP access to the EPC. The SMF+PGW-C may communicate with the HSS+UDM to obtain session-related subscriber information regarding the UE's MA PDU Session request and determine whether to accept the request. The SMF+PGW-C may communicate with the PCF to obtain policies (e.g., AM policy, SM policy, UE policy, etc.) necessary for the UE to use the MA PDU Session connecting 3GPP access to the EPC, and determine the QoS settings for the session and the rules and information related to ATSSS functions to be provided to the UPF and / or the UE. An example of this may be the ATSSS Rule provided to the UE. Examples of ATSSS Rules may be those described in [Table 1] above. SMF+PGW-C may determine which access to use when transmitting ATSSS Rules to the UE, and may refer to at least one of the following information when making this determination:

[0185] 1) If there is a session identifier (e.g., PDU Session ID) among the information received in Step 2, SMF+PGW-C may refer to whether information about the session indicated by the session identifier (e.g., SM Context information) exists in SMF+PGW-C. In this case, whether SM Context information exists may have significance as information indicating that the corresponding PDU Session (or PDN Connection) is managed by SMF+PGW-C and that the session already exists. Therefore, even if SM Context is not stored, SMF+PGW-C may refer to at least one of the information in Table 1 if it can determine that the session identified by the PDU Session ID currently exists between the UE and SMF+PGW-C.

[0186] 2) SMF+PGW-C can refer to whether the ATSSS rule includes a rule associated with the access currently being used by the UE. For example, if the steering mode in the ATSSS rule corresponds to a rule that provides a traffic splitting function such as “Load-Balancing” (and if possible, also refer to whether the splitting ratio corresponds to 100:0), SMF+PGW-C can refer to this to determine that even if the UE receives the ATSSS rule as access corresponding to the EPC connection, it cannot properly use the ATSSS function without establishing access corresponding to the 5GC connection.

[0187] 3) SMF+PGW-C may refer to at least one of the information in Table 1 if there are restrictions or settings regarding the use of MA PDU Sessions, the ATSSS function of the UE and / or network. For example, if there are restrictions or settings where the UE and the network cannot use MA PDU Sessions with only an EPC connection, SMF+PGW-C may refer to this information in determining whether it is possible to control problems that may occur when the UE receives access corresponding to the EPC connection (e.g., problems of using MA PDU Sessions without establishing a 5GC connection).

[0188] 4) SMF+PGW-C may refer to information regarding the capability of the UE to receive or transmit ATSSS rules through the EPC access path of the UE and / or network. For example, if the UE and the network have the capability to receive or transmit ATSSS rules through the 3GPP EPC access path or support such functionality, SMF+PGW-C may provide the ATSSS rules to the UE via the MME or E-UTRAN by embedding them in a PCO or ePCO when it decides to provide the ATSSS rules through the 3GPP EPC access path in steps after Step 3. If the information regarding the UE's capability itself cannot determine whether it is supported by which access type of EPC access (e.g., 3GPP access or Non-3GPP access) (e.g., “ATSSS Rule Provisioning via EPC Support”), SMF+PGW-C may make this determination using the RAT Type value included in the message in which the information regarding the UE's capability is provided.

[0189] The following operations describe a combination with the embodiment of FIG. 5, but can also be applied to the embodiment of FIG. 6.

[0190] 3a. If there is no SM Context for an EPS bearer / QoS flow that supports ATSSS rule provisioning via EPC 3GPP access (e.g., 3GPP EPC access / E-UTRAN) and / or network, the received PDU session ID, access (e.g., 3GPP EPC access / E-UTRAN) and / or network does not exist, SMF+PGW-C may request that ATSSS rules be transmitted first via access (e.g., 3GPP EPC access / E-UTRAN) and that PDU sessions via 5GC access (non-3GPP 5GC access / N3IWF) be dropped if they are not requested for a certain period of time.

[0191] 4. SMF+PGW-C can start a timer to check if a PDU session through 5GC access (e.g., non-3GPP 5GC access / N3IWF) has requested the same PDU session ID as a “MA PDU request” or “ATSSS request”.

[0192] 5. SMF+PGW-C may send a response message to the MME regarding the request to establish a PDN Connection as an MA PDU Session in Step 2. The response message may be sent in various forms, such as Create Session Response. The response message may include information accepting the establishment of a PDN Connection as an MA PDU Session. The information included in the response message may include indicators in the form of “MA PDU Accepted”. Additionally, the response message may include an ATSSS Rule based on the determination in Step 3, 3a. SMF+PGW-C may allow the information transmitted in the response message of Step 5 to be delivered in a container form as is, without the MME understanding or editing it, and in this case, may provide the information included in the response message to the PCO or APCO.

[0193] 6. The MME may transmit part or all of the response message to the request to establish a PDN Connection as an MA PDU Session received in Step 5 to the UE via E-UTRAN. For example, the response message may be transmitted in various forms such as Connection configuration, Direct Transfer, IKEv2 IP address configuration, or PDN Connectivity Response.

[0194] 7. If no PDU session is requested via 5GC access for the same PDU session ID that has a “MA PDU request” or “ATSSS request” until the timer expires, SMF+PGW-C may trigger a resource application disable procedure.

[0195] 8. SMF+PGW-C may request the deletion of a bearer of a PDN Connection in accordance with the initiation of Step 7. The message requesting the deletion of a bearer of a PDN Connection may include information indicating that the deletion of the bearer is requested because the 5GC connection of the MA PDU session has not been established. For example, information indicating the deletion of the bearer may be provided in various forms such as “5GC leg of MA PDU Session has not initiated”, “PDN connection inactivity timer expiry”, or “PDU session inactivity timer expiry”.

[0196] 9. Based on the request to delete the bearer of the PDN Connection received from SMF+PGW-C, the MME may send a request to disable the bearer of the PDN Connection or an RRC Connection Reconfiguration to the UE via E-UTRAN.

[0197] 10. If the UE decides not to request a 5GC connection for the MA PDU session via N3IWF, it may send a response to the MME.

[0198] 11-16. A bearer deletion operation may be performed.

[0199] FIG. 8 illustrates the configuration of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0200] A terminal according to one embodiment of the present disclosure may include a processor (830) that controls the overall operation of the terminal, a transceiver (810) including a transmitter and a receiver, and a memory (820). Of course, it is not limited to the examples described above, and the terminal may include more configurations than those shown in FIG. 8, or fewer configurations.

[0201] According to one embodiment of the present disclosure, the transceiver (810) may transmit and receive signals with network entities, a base station, or another terminal. The signals transmitted and received with the network entities, a base station, or another terminal may include control information and data. Additionally, the transceiver (810) may receive a signal through a wireless channel and output it to a processor (830), and transmit the signal output from the processor (830) through a wireless channel.

[0202] According to one embodiment of the present disclosure, the processor (830) can control the terminal to perform any one of the above-described embodiments. Meanwhile, the processor (830), memory (820), and transceiver (810) are not necessarily implemented as separate modules, and can be implemented as a single component in the form of a single chip. Also, the processor (830) and the transceiver (810) can be electrically connected. Additionally, the processor (830) may include an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, a controller, or at least one processor.

[0203] According to one embodiment of the present disclosure, the memory (820) may store data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the memory (820) provides the stored data upon the request of the processor (830). The memory (820) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, the memory (820) may be a plurality of. Furthermore, the processor (830) may perform the aforementioned embodiments based on a program for performing the aforementioned embodiments of the present disclosure stored in the memory (820).

[0204] FIG. 9 illustrates the configuration of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0205] The base station of FIG. 9 may refer to the RAN node or BS described in the aforementioned embodiments.

[0206] A base station according to one embodiment of the present disclosure may include a processor (930) that controls the overall operation of the base station, a transceiver (910) including a transmitter and a receiver, and a memory (920). Of course, it is not limited to the above examples, and the base station may include more or fewer configurations than the configuration shown in FIG. 9.

[0207] According to one embodiment of the present disclosure, the transceiver (910) may transmit and receive a signal with at least one of a terminal, another base station, or a network entity. The signal to be transmitted and received may include at least one of control information and data.

[0208] According to one embodiment of the present disclosure, the processor (930) may control the overall operation of the base station to perform any one of the above-described embodiments. Meanwhile, the processor (930), the transceiver (910), and the memory (920) are not necessarily implemented as separate modules, but may be implemented as a single component in the form of a single chip. Furthermore, the processor (930) may be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor. The transceiver (910) may include at least one communication interface for transmitting and receiving signals via wired / wireless to a terminal, another base station, or a network entity.

[0209] According to one embodiment of the present disclosure, the memory (920) may store data such as a basic program, an application program, and configuration information for the operation of the base station. Additionally, the memory (920) provides the stored data upon request from the processor (930). The memory (920) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, there may be multiple memory (920). Additionally, the processor (930) may perform at least one of the aforementioned embodiments based on a program for performing an operation according to at least one of the aforementioned embodiments of the present disclosure stored in the memory (920).

[0210] FIG. 10 illustrates the configuration of a network entity in a wireless communication system according to one embodiment of the present disclosure.

[0211] A network entity according to one embodiment of the present disclosure may include a processor (1030) that controls the overall operation of the network entity, a transceiver (1010) including a transmitter and a receiver, and a memory (1020). Of course, it is not limited to the examples described above, and the network entity may include more or fewer configurations than the configuration shown in FIG. 10.

[0212] According to one embodiment of the present disclosure, the transceiver (1010) may transmit and receive a signal with at least one of other network entities, a base station, or a terminal. The signal transmitted and received with at least one of other network entities, a base station, or a terminal may include control information and data.

[0213] According to one embodiment of the present disclosure, the processor (1030) can control a network entity to perform any one of the above-described embodiments. Meanwhile, the processor (1030), memory (1020), and transceiver (1010) are not necessarily implemented as separate modules, and can be implemented as a single component in the form of a single chip. Also, the processor (1030) and the transceiver (1010) can be electrically connected. Additionally, the processor (1030) may include an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, a controller, or at least one processor.

[0214] According to one embodiment of the present disclosure, the memory (1020) may store data such as a basic program, an application program, and configuration information for the operation of a network entity. In particular, the memory (1020) provides the stored data upon request by the processor (1030). The memory (1020) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, the memory (1020) may be a plurality of. Furthermore, the processor (1030) may perform the aforementioned embodiments based on a program for performing the aforementioned embodiments of the present disclosure stored in the memory (1020).

[0215] It should be noted that the aforementioned configuration diagrams, exemplary diagrams of control / data signal transmission and reception methods, and exemplary diagrams of operation procedures are not intended to limit the scope of the embodiments of the present disclosure. That is, all of the aforementioned components, entities, or steps of operation should not be interpreted as essential components for implementing the disclosure, and may be implemented to the extent that the essence of the disclosure is not compromised even if only some components are included.

[0216] The operations of the embodiments described above can be realized by providing a memory device storing the corresponding program code in any component within the device. That is, the control unit within the device can execute the operations described above by reading the program code stored in the memory device by a processor or a CPU (Central Processing Unit) and executing it.

[0217] The entities or various components of terminal devices and modules described in this disclosure may be operated using hardware circuits, such as, for example, complementary metal oxide semiconductor-based logic circuits, firmware, software, and / or a combination of hardware and firmware and / or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and application-specific semiconductors.

[0218] Methods according to the claims or embodiments described in the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0219] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the claims or embodiments described in the specification of this disclosure.

[0220] 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 device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in a memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0221] Additionally, the program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0222] In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0223] Meanwhile, the embodiments disclosed in this specification and drawings described above are merely specific examples provided to facilitate the explanation and understanding of the content of the invention and are not intended to limit the scope of the invention. Accordingly, the scope of the invention should be interpreted to include all modifications or variations derived based on the technical concept of the invention, in addition to the embodiments disclosed herein.

[0224] The electronic device for implementing, operating, and performing the various embodiments of the present disclosure may be of various forms. The electronic device may include, for example, a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a consumer electronics device. The electronic device according to the embodiments of the present disclosure is not limited to the aforementioned devices.

[0225] The various embodiments of the present disclosure and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of such embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more items unless the relevant context clearly indicates otherwise. In the present disclosure, each of the phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B, or C” may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as “first,” “second,” or “first” or “second” may be used simply to distinguish a component from another component and do not limit the components in any other aspect (e.g., importance or order). Where any (e.g., first) component is referred to as “coupled” or “connected” to another (e.g., second) component, with or without the terms “functionally” or “communicationly,” it means that the component may be connected to the other component directly (e.g., via a wire), wirelessly, or through a third component.

[0226] The term “module” as used in various embodiments of the present disclosure may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be a component formed integrally or a minimum unit of a component or part thereof that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0227] Various embodiments of the present disclosure may be implemented as software (e.g., a program) comprising one or more instructions stored in a storage medium (e.g., internal memory or external memory) readable by a machine (e.g., an electronic device). For example, a processor (e.g., a processor) of the machine (e.g., an electronic device) may call at least one of the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to at least one called instruction. One or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The storage medium readable by the machine may be provided in the form of a non-transitory storage medium. Here, "non-transitory" simply means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic waves), and this term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily in the storage medium.

[0228] According to one embodiment, the method according to various embodiments of the present disclosure may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0229] According to various embodiments, each component (e.g., module or program) of the described components may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to various embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as they were performed by the corresponding component among the multiple components prior to integration. According to various embodiments, operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically; one or more of the operations may be executed in a different order; may be omitted; or one or more other operations may be added.

Claims

1. A method performed by a terminal in a wireless communication system, A step of transmitting a first message to request a PDN (packet data network) connection through a first access network using an SMF (session management function) + PGW-C (packet data network gateway control plane); and The method includes the step of receiving a second message from the above SMF+PGW-C, which includes a response to a request for the PDN connection through the first access network, and The above PDN connection is based on a multi-access (MA) PDU (protocol data unit) session, and A method in which the above MA PDU session is associated with paths connecting to a plurality of access networks including a core network and the first access network.

2. In Paragraph 1, A method wherein the first message comprises at least one of information regarding the support of access traffic steering, switching, and splitting (ATSS) of the terminal or identification information of the MA PDU session.

3. In Paragraph 1, The above second message includes information regarding ATSSS rules, and The above ATSSS rule is a method based on the establishment of the above MA PDU session.

4. In paragraph 1, the above method is: A step of receiving a third message from the above SMF+PGW-C requesting the deletion of a bearer of the PDN connection; and It further includes a step of determining the deletion of the above bearer, A method in which the request for deletion of the above bearer is based on the inactivity or non-existence of the above PDN connection based on a timer.

5. In a method performed by SMF (session management function) + PGW-C (packet data network gateway control plane) in a wireless communication system, A step of receiving a first message from a terminal to request a PDN (packet data network) connection through a first access network; and The method includes the step of transmitting a second message to the terminal, which includes a response to a request for the PDN connection through the first access network, and The above PDN connection is based on a multi-access (MA) PDU (protocol data unit) session, and A method in which the above MA PDU session is associated with paths connecting to a plurality of access networks including a core network and the first access network.

6. In Paragraph 5, A method wherein the first message comprises at least one of information regarding the support of access traffic steering, switching, and splitting (ATSS) of the terminal or identification information of the MA PDU session.

7. In Paragraph 5, The above second message includes information regarding ATSSS rules, and The above ATSSS rule is a method based on the establishment of the above MA PDU session.

8. In paragraph 5, the above method is: A step of identifying the inactivity or absence of the PDN connection based on a timer; and A method further comprising the step of transmitting a third message to the terminal requesting the deletion of the bearer of the PDN connection.

9. In a terminal of a wireless communication system, Transmitter / receiver; and It includes at least one control unit connected to the above-mentioned transmitting and receiving unit, and The above at least one control unit is: Transmitting a first message to request a PDN (packet data network) connection through a first access network using an SMF (session management function) + PGW-C (packet data network gateway control plane), and From the above SMF+PGW-C, receive a second message including a response to a request for the PDN connection through the first access network, and The above PDN connection is based on a multi-access (MA) PDU (protocol data unit) session, and A terminal in which the above MA PDU session is associated with paths connecting to a plurality of access networks including a core network and the first access network.

10. In Paragraph 9, A terminal in which the first message comprises at least one of information regarding the support of access traffic steering, switching, and splitting (ATSSS) of the terminal or identification information of the MA PDU session.

11. In Paragraph 9, The above second message includes information regarding ATSSS rules, and The above ATSSS rule is based on the establishment of the above MA PDU session, a terminal.

12. In paragraph 9, the at least one control unit is: From the above SMF+PGW-C, receive a third message requesting the deletion of the bearer of the PDN connection, and, Deciding to delete the above bearer, A terminal whose request for deletion of the above bearer is based on the inactivity or non-existence of the above PDN connection based on a timer.

13. In a wireless communication system, regarding SMF (session management function) + PGW-C (packet data network gateway control plane), Transmitter / receiver; and It includes at least one control unit connected to the above-mentioned transmitting and receiving unit, and The above at least one control unit is: Receive a first message from a terminal to request a PDN (packet data network) connection through a first access network, and The above terminal transmits a second message containing a response to a request for the PDN connection through the first access network, and The above PDN connection is based on a multi-access (MA) PDU (protocol data unit) session, and The above MA PDU session is associated with paths connecting to a plurality of access networks including a core network and the first access network, SMF+PGW-C.

14. In Paragraph 13, SMF+PGW-C, wherein the first message comprises at least one of information regarding the support of access traffic steering, switching, and splitting (ATSS) of the terminal or identification information of the MA PDU session.

15. In Paragraph 13, The above second message includes information regarding ATSSS rules, and The above ATSSS rule is based on the establishment of the above MA PDU session, SMF+PGW-C.

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