CN118891921A - Method and apparatus for providing access path in wireless communication system - Google Patents

Abstract

The present disclosure relates to a fifth generation (5G) or sixth generation (6G) communication system for supporting a higher data transmission rate. According to the present disclosure, an operation method of a UE in a wireless communication system includes: sending a registration request message including an access service steering, switching, splitting (ATSSS) path switching indication to a target access network entity, receiving a registration acceptance message including an access path switching timer value from the target access network entity in response to the registration request message, sending a packet data unit (PDU) session establishment request message to an access and mobility management function (AMF) via the target access network entity based on the access path switching timer value, and releasing the PDU session with the source access network entity.

Description

Method and apparatus for providing an access path in a wireless communication system

Technical Field

The present disclosure relates to a device and method for providing an access path in a wireless communication system or a mobile communication system, and more specifically, to a method and device for providing access traffic steering, switching, splitting (ATSSS) functions in a wireless communication system.

Background Art

The fifth generation (5G) mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in the "below 6 GHz" frequency band such as 3.5 GHz, but also in the "above 6 GHz" frequency band called mmWave (millimeter wave) including 28 GHz and 39 GHz. In addition, the implementation of 6G mobile communication technology (called super 5G system) in the terahertz frequency band (for example, the 95 GHz to 3 THz frequency band) has been considered in order to achieve a transmission rate fifty times faster than that of 5G mobile communication technology and an ultra-low latency one-tenth of that of 5G mobile communication technology.

At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC), there has been ongoing standardization on the following technologies: beamforming and massive MIMO for mitigating radio wave path loss in mmWave and increasing radio wave transmission distance in mmWave, parameter sets supporting dynamic operation for efficient utilization of mmWave resources and time slot formats (e.g., operating multiple subcarrier spacings), initial access technology for supporting multi-beam transmission and broadband, definition and operation of BWP (bandwidth part), new channel coding methods such as LDPC (low-density parity check) codes for large-volume data transmission and polar codes for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing dedicated networks dedicated to specific services.

Currently, in view of the services supported by the 5G mobile communication technology, discussions are ongoing on the improvement and performance enhancement of the initial 5G mobile communication technology, and there is already physical layer standardization on technologies such as V2X (Vehicle to Everything) for assisting driving decisions made by an autonomous vehicle based on information about the position and status of the vehicle transmitted by the vehicle and for enhancing user convenience, NR-U (New Radio Unlicensed) for system operation intended to comply with various regulatory-related requirements in unlicensed bands, NR UE power saving, non-terrestrial network (NTN) (which is UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable), and positioning.

In addition, there is ongoing standardization of air interface architecture/protocol aspects of technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing nodes for network service area extension by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (two-step RACH for NR) for simplifying the random access procedure. Standardization is also ongoing on the 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and system architecture/services for mobile edge computing (MEC) for receiving services based on UE location.

As 5G mobile communication systems are commercialized, the number of connected devices, which has been growing exponentially, will be connected to the communication network, and it is therefore expected that enhanced functions and performance of the 5G mobile communication systems and the integrated operation of connected devices will be necessary. To this end, new research related to extended reality (XR) is arranged for effectively supporting AR (augmented reality), VR (virtual reality), MR (mixed reality), etc., improving 5G performance and reducing complexity by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

Furthermore, such developments in 5G mobile communication systems will serve as a foundation not only for the development of new waveforms that provide terahertz band coverage for 6G mobile communication technology, multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas, metamaterial-based lenses and antennas for improving terahertz band signal coverage, high-dimensional spatial multiplexing technologies using OAM (orbital angular momentum), and RIS (reconfigurable smart surfaces), but also for the development of full-duplex technologies that increase the frequency efficiency of 6G mobile communication technology and improve system networks, AI-based communication technologies for achieving system optimization by leveraging satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for achieving services at a complexity level that exceeds the operational capability limits of UEs by utilizing ultra-high-performance communication and computing resources.

The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above may be applicable as prior art with respect to the present disclosure.

Summary of the invention

Technical issues

In the 5G system, when the UE uses a PDU session, between the UE and the 5G core network, a connection via only one access path is possible for each access network type (3GPP access, non-3GPP access). In addition, in the 5G core network, a UE can have only one registration management state and one connection management state per access network type. Therefore, when it is necessary to switch from one access path to another access path when the UE uses a multiple access protocol data unit (MA PDU) session via multiple access paths, a new access path may not be added without deregistration and session release regarding the access path to be switched.

Therefore, the present disclosure provides a method and apparatus for providing access path switching for a UE without session release and logout when the UE is using sessions via multiple access paths in a 5G system.

Solution to the problem

According to the present disclosure, an operation method of a UE in a wireless communication system includes: sending a registration request message including an access service steering, switching, splitting (ATSSS) path switching indication to a target access network entity, receiving a registration acceptance message including an access path switching timer value from the target access network entity, in response to the registration request message, sending a packet data unit (PDU) session establishment request message to an access and mobility management function (AMF) via the target access network entity based on the access path switching timer value, and releasing the PDU session with the source access network entity.

According to the present disclosure, an operation method of an AMF in a wireless communication system includes: receiving a registration request message including an access service steering, switching, splitting (ATSSS) path switching indication from a UE via a target access network entity; when the ATSSS path can be switched based on the registration request message, sending a PDU session update request message indicating the ATSSS path switching indication, a radio access technology (RAT) type of a target access network, and a RAT type of a source access network to a session management function (SMF); receiving an update response message including an access path switching timer value from the SMF in response to the PDU session update request message; sending a registration acceptance message including an access path switching timer value to the UE via the target access network based on the update response message; and receiving a PDU session establishment request message from the UE via the target access network entity in response to the registration acceptance message.

According to the present disclosure, the operation method of SMF in a wireless communication system includes: receiving a PDU session update request message indicating an ASSS path switching indication of a UE, a RAT type of a target access network, and a RAT type of a source access network from an AMF, sending a PDU session update response message including an access path switching timer value to the AMF in response to the PDU session update response message, receiving a PDU session creation request message from the AMF in response to the PDU session update response message, and terminating the PDU session of the UE regarding the source access network based on the PDU session creation request message.

Advantageous Effects of the Invention

According to the device and method of the present disclosure, when a UE uses a service in a wireless communication system by using a 5G core network and a multiple access protocol data unit (MA PDU) session, an access path can be switched without logout and session release.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

FIG1 shows a 5G system structure according to an embodiment of the present disclosure;

FIG2 shows a 5G system structure for ATSSS function support according to an embodiment of the present disclosure;

3A to 3C show a flowchart of a method for switching an access path in a wireless communication system and processes related thereto according to an embodiment of the present disclosure;

4A to 4D show a flowchart of a method for switching an access path of a UE 10 in a wireless communication system and processes related thereto according to an embodiment of the present disclosure;

5A to 5D show a flow chart of a method for switching an access path of a UE in a wireless communication system and related processes thereof according to an embodiment of the present disclosure;

FIG6 shows a UE in a wireless communication system according to an embodiment of the present disclosure;

FIG. 7 illustrates an NG-RAN in a wireless communication system according to an embodiment of the present disclosure;

FIG8 shows a source access network in a wireless communication system according to an embodiment of the present disclosure;

FIG9 shows a target access network in a wireless communication system according to an embodiment of the present disclosure;

FIG10 shows an AMF in a wireless communication system according to an embodiment of the present disclosure;

FIG11 shows an SMF in a wireless communication system according to an embodiment of the present disclosure;

FIG12 shows a UPF in a wireless communication system according to an embodiment of the present disclosure;

FIG13 shows a PCF in a wireless communication system according to an embodiment of the present disclosure;

FIG. 14 illustrates a UDM in a wireless communication system according to an embodiment of the present disclosure; and

FIG. 15 shows a DN in a wireless communication system according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Advantageous effects obtainable from the present disclosure may not be limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present disclosure pertains through the following description.

Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives are meant to include, but are not limited to; the term "or" is inclusive, meaning and/or; the phrases "associated with" and "associated with" and their derivatives may mean include, be included within, interconnected with, contain, be contained within, connect to or be connected with, be coupled to or be coupled with, be communicative with, cooperate with, interleave, juxtapose, be proximate to, be bound to or be bound with, have, have the property of, etc.; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

In addition, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or a portion thereof, suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD), or any other type of memory. "Non-transitory" computer-readable media do not include wired, wireless, optical, or other communication links that transmit temporary electrical or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and rewrite data later, such as rewritable optical disks or erasable memory devices.

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

FIG. 1 to FIG. 15 discussed below and the various embodiments used to describe the principles of the present disclosure in this patent document are intended only as illustrations and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any suitably arranged system or device.

By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will be apparent. However, the present disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the attached claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements.

Here, it should be understood that each box of the flowchart diagram and the combination of boxes in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for implementing the function specified in one or more flowchart boxes. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing device to act in a specific way, so that the instructions stored in the computer-usable or computer-readable memory produce a product including an instruction device that implements the function specified in one or more flowchart boxes. The computer program instructions can also be loaded on a computer or other programmable data processing device so that a series of operating steps are performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the function specified in one or more flowchart boxes.

In addition, each frame of the flowchart diagram can represent a module, a fragment or a portion of a code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions mentioned in the frame may not occur in order. For example, two frames shown in succession can actually be performed substantially simultaneously, or these frames can sometimes be performed in reverse order, depending on the functions involved.

As used in the embodiments of the present disclosure, "unit" refers to a software element or hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, "unit" does not always have a meaning limited to software or hardware. "Unit" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by the "unit" can be combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". In addition, elements and "units" can be implemented as one or more CPUs in a reproduction device or a secure multimedia card. In addition, the "unit" in the embodiment can include one or more processors.

In the following description of the present disclosure, when it is determined that a detailed description of a known function or configuration incorporated herein may make the subject matter of the present disclosure unnecessarily unclear, the description will be omitted. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

In the following description, for the sake of convenience of description, terms for identifying access 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 illustratively used. Therefore, the present disclosure is not limited to the terms used below, and other terms relating to subjects with equivalent technical meanings may be used.

In the following description, for the sake of convenience, the terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard will be used to describe the present disclosure. However, the present disclosure is not limited to these terms and names, and can be applied to systems conforming to other standards in the same manner. In the present disclosure, the term "eNB" can be used interchangeably with the term "gNB". That is, a base station described as an "eNB" can indicate a "gNB". In addition, the term "terminal" can refer not only to mobile phones, NB-IoT devices, and sensors, but also to any other wireless communication device.

In the following description, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Of course, examples of base stations and terminals are not limited thereto.

In particular, the present disclosure may be applied to 3GPP NR (5th generation mobile communication standard). The present disclosure may be applied to smart services based on 5G communication technology and IoT-related technology (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail business, security and safety-related services, etc.). In the present disclosure, the term "eNB" may be used interchangeably with the term "gNB". That is, a base station described as an "eNB" may indicate a "gNB". In addition, the term "terminal" may refer not only to mobile phones, NB-IoT devices, and sensors, but also to any other wireless communication devices.

The wireless communication system is developing into a broadband wireless communication system for providing high-speed and high-quality packet data services using communication standards such as High Speed Packet Access (HSPA) of 3GPP, LTE (Long Term Evolution) or Evolved Universal Terrestrial Radio Access (E-UTRA), Advanced LTE (LTE-A), LTE-Pro, High Speed Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), IEEE 802.16e, etc., as well as typical voice-based services.

As a typical example of a broadband wireless communication system, the LTE system adopts an orthogonal frequency division multiplexing (OFDM) scheme in the downlink (DL) and a single carrier frequency division multiple access (SC-FDMA) scheme in the uplink (UL). The uplink indicates a radio link through which a user equipment (UE) (or a mobile station (MS)) transmits data or a control signal to a base station (BS) (a generation Node B (gNB) or an eNode B (eNB)), and the downlink indicates a radio link through which a base station transmits data or a control signal to a UE. The above-mentioned multiple access scheme separates the data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information to each user to avoid overlapping with each other, that is, establishing orthogonality.

Since the post-LTE communication system (i.e., 5G communication system) must freely reflect various requirements of users, service providers, etc., it is necessary to support services that meet various requirements. Services considered in the 5G communication system include enhanced mobile broadband (eMBB) communication, massive machine type communication (mMTC), ultra-reliable low latency communication (URLLC), etc.

According to some embodiments, eMBB is intended to provide a higher data rate than that supported by existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, for a single base station, eMBB must provide a peak data rate of 20Gbps in the downlink and a peak data rate of 10Gbps in the uplink. In addition, the 5G communication system must provide an increased user-perceived data rate as well as a maximum data rate to the UE. In order to meet such requirements, it is necessary to improve the transmission/reception technology including further enhanced multiple-input multiple-output (MIMO) transmission technology. In addition, a frequency bandwidth greater than 20MHz can be used in a frequency band of 3 to 6GHz or 6GHz or higher to obtain the data rate required by the 5G communication system, instead of using a transmission bandwidth of up to 20MHz to send signals in the 2GHz band used in LTE.

In addition, mMTC is considered to support application services such as the Internet of Things (IoT) in the 5G communication system. mMTC has requirements such as supporting the connection of a large number of UEs in a cell, enhanced coverage of UEs, improved battery time, UE cost reduction, etc., in order to effectively provide the Internet of Things. Since the Internet of Things provides communication functions while being provided to various sensors and various devices, the Internet of Things must support a large number of UEs in a cell (e.g., 1,000,000 UEs/km2). In addition, a UE supporting mMTC may require a wider coverage than the coverage of other services provided by the 5G communication system because the UE may be located in a shadow area (such as a basement of a building) that is not covered by the cell due to the nature of the service. A UE supporting mMTC must be configured to be inexpensive and may require a very long battery life, such as 10 to 15 years, because it is difficult to frequently replace the battery of the UE.

Finally, URLLC, as a cellular-based mission-critical wireless communication service, can be used for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, emergency alerts, etc. Therefore, URLLC must provide communications with ultra-low latency and ultra-high reliability. For example, services supporting URLLC must meet an air interface delay of less than 0.5ms and also require a packet error rate of ^10-5 or less. Therefore, for services supporting URLLC, the 5G system must provide a shorter transmission time interval (TTI) than that of other services, and may also require a design for allocating a large amount of resources in the frequency band in order to ensure the reliability of the communication link.

The above three services (i.e., eMBB, URLLC, and mMTC) considered in the 5G communication system can be multiplexed and transmitted in a single system. In this case, different transmission/reception technologies and transmission/reception parameters can be used between services to meet different requirements of the corresponding services. However, the above mMTC, URLLC, and eBB are merely examples of different service types, and the service types to which the present disclosure is applied are not limited thereto.

In addition, in the following description of the embodiments of the present disclosure, LTE, LTE-A, LTE-Pro or NR systems will be described by way of example, but the embodiments of the present disclosure may be applied to other communication systems with similar backgrounds or channel types. In addition, based on the determination of those skilled in the art, the embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure.

The terms to be described below are defined in consideration of the functions in the present disclosure and may differ depending on the user, the user's intention or custom. Therefore, the definition of the terms should be made based on the contents throughout the specification.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same or similar elements are represented by the same or similar reference numerals as much as possible. In addition, it should be noted that the drawings of the present disclosure are provided to help understand the present disclosure, and the present disclosure is not limited by the shapes or arrangements shown in the accompanying drawings. In addition, a detailed description of known functions or configurations that may make the subject matter of the present disclosure unclear will be omitted. It should be noted that in the following description, only the parts required for understanding the operation according to various embodiments will be described, and the description of other parts will be omitted so as not to obscure the subject matter of the present disclosure. In addition, in the description of various embodiments of the present disclosure, for the sake of description, the terms adopted in some communication standards (e.g., the Third Generation Partnership Project (3GPP)) will be used illustratively. The various embodiments of the present disclosure can also be easily applied to other communication systems by modification.

FIG1 shows the structure of a 5G system according to an embodiment of the present disclosure.

1 , the structure of the 5G system may include various components (i.e., network functions (NFs)). FIG. 1 shows 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, a terminal, i.e., a user equipment (UE) 10, which correspond to some components. In addition, FIG. 1 shows 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.

Each device shown in Figure 1 can be implemented as a server or device, and can be implemented as a network slice instance as described above. When implemented as a network slice instance, two or more identical or different network slice instances can be implemented in one server or device, and one network slice instance can be implemented in two or more servers or devices.

Each of the above NFs can support the following functions.

The AUSF 160 may process and store data used for authentication of the UE 10 .

The AMF 120 may provide functions for access and mobility management on a UE basis, and each UE may be connected to one AMF in principle. Specifically, the AMF 120 may support functions such as CN node signaling for mobility between 3GPP access networks, termination of the radio access network (RAN) CP interface (i.e., N2 interface), termination of NAS signaling (N1), NAS signaling security (NAS encryption 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 interception (for interfaces to AMF events and LI systems), transmission and provision of session management (SM) messages between UE and SMF, transparent proxy for SM message routing, access authentication for access authorization including roaming authorization check, transmission and provision of SMS messages between UE and short message service function (SMSF), security anchor function (SAF) and/or security context management (SCM). Some or all of the functionality of the AMF 120 may be supported within a single AMF instance operating as one AMF.

The DN 180 may refer to, for example, an operator service, Internet access, or a third-party service. The DN 180 may transmit a downlink protocol data unit (PDU) to the UPF 110 or may receive a PDU transmitted from the UE 10 via the UPF 110 .

PCF 140 may receive packet flow information from application servers and provide functions for determining policies, such as mobility management and session management. Specifically, PCF 140 may support the following functions: supporting a unified policy framework to manage network operations, providing policy rules to enable control plane functions (e.g., AMF, SMF, etc.) to implement policy rules, and implementing a front end to access relevant subscription information for policy decisions in a user data repository (UDR).

SMF 130 can provide session management functions, and when the UE has multiple sessions, each session can be managed by a different SMF. Specifically, SMF 130 can support functions such as session management (e.g., session establishment, modification and termination, including maintaining tunnels between UPF and AN nodes), UE IP address allocation and management (optionally including authentication), selection and control of UP functions, configuration of service steering for routing services to appropriate destinations in UPF, termination of interfaces toward policy control functions, control parts of policy enforcement and quality of service (QoS), legal interception (for interfaces to SM events and LI systems), termination of the SM part of NAS messages, downlink data notification, initiator of AN-specific SM information (transmitted to AN via AMF through N2), SSC mode determination of sessions, and roaming functions. As described above, some or all functions of SMF 130 can be supported within a single SMF instance operating as one SMF.

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

FE may include UDM FE responsible for location management, subscription management, credential processing, etc., and PCF-FE responsible for policy control. UDM 170 may store data required for functions provided by UDM-FE and policy profiles required by PCF. Data stored in UDR may include policy data and user subscription data, and user subscription data includes subscription identifiers, security credentials, subscription data related to access and mobility, and subscription data related to sessions. UDM-FE may access subscription information stored in UDR and support functions such as authentication credential processing, user identity processing, access authentication, enrollment/mobility management, subscription management, and SMS management.

The UPF 110 may send the downlink PDU received from the DN 180 to the UE 10 via the (R)AN 20, and may send the uplink PDU received from the UE 10 to the DN 180 via the (R)AN 20. Specifically, the UPF 110 may support an anchor point for intra/inter-RAT mobility, an external PDU session point for interconnection to a data network, packet routing and forwarding, a user plane portion and packet inspection for policy rule enforcement, legal interception, service usage reporting, an uplink classifier to support routing of service flows to a data network, a branch point to support multi-homed PDU sessions, QoS processing for the user plane (e.g., packet filtering, gating, uplink/downlink rate enforcement), uplink service verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in uplink and downlink, downlink packet buffering, and downlink data notification triggering functions. Some or all of the functions of the UPF 110 may be supported within a single UPF instance operating as one UPF.

The AF 150 may interact with the 3GPP core network to provide services (eg, support functions such as application influencing on traffic routing, access to network capability exposure, and interaction with a policy framework for policy control).

The (R)AN 20 may be collectively referred to as a new radio access network supporting both Evolved-UTRA, an evolved version of 4G radio access technology, and New Radio (NR) (eg, gNB).

The gNB 20 may support functions such as for radio resource management (i.e., radio bearer control), radio admission control, connection mobility control, dynamic allocation of resources to the UE 10 in uplink/downlink (i.e., scheduling), Internet Protocol (IP) header compression, encryption and integrity protection of user data flows, selection of the AMF 120 upon attach of the UE 10 when routing to the AMF 120 is not determined from information provided to the UE 10, user plane data routing to the UPF 110, control plane information routing to the AMF 120, connection establishment and termination, scheduling and transmission of paging messages (generated from the AMF 120), scheduling and transmission of system broadcast information (generated from the AMF 120 or operation and maintenance (O&M)), measurement and measurement report configuration for mobility and scheduling, transport level packet marking in uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in inactive mode 10. NAS message distribution function, NAS node selection function, radio access network sharing, dual connectivity, and close interworking between NR and E-UTRA.

UE 10 may refer to a user equipment. A user equipment may be referred to as a terminal, a mobile equipment (ME), or a mobile station (MS). In addition, a user equipment may be a portable device such as a laptop computer, a mobile phone, a personal digital assistant (PDA), a smart phone, and a multimedia device, or may be a non-portable device such as a personal computer (PC) and a vehicle-mounted device. Hereinafter, a description will be given by referring to a user equipment (UE) or a terminal.

For clarity of illustration, the Network Exposure Function (NEF) device and the NF Repository Function (NRF) device are not shown in FIG. 1 , but the NF may interact with the NEF and the NRF as needed.

The NRF (not shown in FIG1 ) may support a service discovery function. When a second NF discovery request is received from a first NF instance, the NRF may provide the first NF instance with information about the second NF instance discovered after performing the second NF discovery operation. In addition, the NRF may maintain available NF instances and the services they support.

For convenience of description, FIG. 1 shows a reference model for a case in which the UE 10 accesses one DN 180 by using one PDU session, but the present disclosure is not limited thereto.

UE 10 can access two (i.e., local and central) data networks simultaneously by using multiple PDU sessions. In this case, two SMFs can be selected for different PDU sessions. However, each SMF can have the ability to control both the local UPF and the central UPF within a PDU session.

Additionally, the UE 10 may simultaneously access two (ie, regional and centralized) data networks provided within a single PDU session.

In the 3GPP system, a conceptual link connecting NFs in the 5G system is defined as a reference point. The following shows the reference points included in the structure of the 5G system shown in FIG1:

-N1: reference point between UE and AMF;

-N2: reference point between (R)AN and AMF;

-N3: reference point between (R)AN and UPF;

-N4: reference point between SMF and UPF;

-N5: reference point between PCF and AF;

-N6: Reference point between UPF and data network;

-N7: reference point between SMF and PCF;

-N8: Reference point between UDM and AMF;

-N9: reference point between two core UPFs;

-N10: Reference point between UDM and SMF;

-N11: Reference point between AMF and SMF;

-N12: reference point between AMF and AUSF;

-N13: Reference point between UDM and Authentication Server Function (AUSF);

-N14: reference point between two AMFs; and

- N15: Reference point between PCF and AMF in case of non-roaming scenario, reference point between PCF and AMF in visited network in case of roaming scenario.

In the following description, the terminal may refer to UE 10, and the terms UE and terminal may be used interchangeably. In this case, the terminal should be understood as UE 10 unless otherwise defined.

The UE can access a data network (e.g., a network providing Internet services) via a 5G system to establish a session, and can distinguish each data network by using an identifier called a data network name (DNN). When the UE connects the network system and the session, the DNN can be used to determine the NFs related to the user plane, the interfaces between the NFs, and the operator policies. The DNN can be used, for example, to select the SMF and UPF for a PDU session, and can be used to select the interface between the data network and the UPF (e.g., the N6 interface) for the PDU session. In addition, the DNN can be used to determine the mobile communication operator policy to be applied to the PDU session.

The ATSSS function refers to a function for transmitting data services via one or more accesses by utilizing the above-mentioned 3GPP access and/or non-3GPP access between the UE and the 5G core network. A representative example of the ATSSS function may include the following case: when the 5G core network determines that the user plane resources between the UE and the data network (DN) 180 are insufficient or a load is generated in the resource management capacity of the network, data is distributed and sent by activating both 5G access and Wi-Fi access, instead of sending the data service via only one of the 5G access or Wi-Fi access.

FIG2 shows an access service steering, switching, splitting (ATSSS) support structure in a 3GPP 5G system according to an embodiment of the present disclosure.

2 , UE 10 may access a mobile communication network (eg, 3GPP access 210) and a non-mobile communication network (eg, non-3GPP access 220). The ATSSS function may include a steering function and a steering mode.

The steering function may determine the transmission protocol between the UPF of the transmitting device and the UPF of the receiving device. The steering function may be determined according to the transport layer that determines the service steering, switching, and splitting. When the Multipath TCP (MPTCP) (IETF RFC 8684) protocol located at a layer higher than the IP layer is used, the steering function may correspond to the "MPTCP function", and when the steering function is determined in a layer lower than the IP layer, the steering function may correspond to the "ATSSS-Low Layer (ATSSS-LL) function". The UE may include the MPTCP function 11 and the ATSSS-LL function 12.

UEs and networks supporting the MPTCP function may communicate with the MPTCP proxy function 111 configured separately in the UPF 110. The MPTCP function may only control TCP services supporting the MPTCP protocol. When the ATSSS-LL function is supported, the MPTCP function may not include a separate proxy component in the UPF and control all types of TCP services.

The steering mode defines the methods used to steer, switch and split data traffic.

In addition, the UPF 110, the SMF 130, and the PCF 140 according to the present disclosure may perform a separate control operation for access of the UE 10. The control operation will be further described with reference to drawings described later.

As shown in the figure, the UPF 110 according to the present disclosure may include an MPTCP proxy function 111 therein.

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 the uplink and downlink and whether the 3GPP access and the non-3GPP access are currently active. The steering function and steering mode that can be supported by the core network can be determined based on the information provided by the PMF, which has an overall impact on the parameter determination of the N3 and N4 connections. The PMF may be included in the UPF 110 and the UE 10, respectively. The PMF included in the UPF and the PMF included in the UE may be referred to as the UPF-PMF 112 and the UE-PMF 113, respectively.

As shown in FIG. 1 , when utilizing the ATSSS functionality described in FIG. 2 , traffic may be sent via multiple paths between a protocol data unit or packet data unit (PDU) session anchor user plane function (UPF) 110 and a user equipment (UE) 10 .

3A to 3C show flow charts illustrating a method for switching an access path of a UE 10 in a wireless communication system and processes related thereto according to the present disclosure.

Step 0: UE 10 may send uplink data to UPF 110 via source access network 310. UPF 110 may transmit uplink data received from UE 10 to DN 180. UPF 110 may transmit downlink data received from DN 180 to UE 10 via source access network 310.

Step 1: The UE 10 may determine to switch one access path among the access paths using the MA PDU session. For example, when the UE 10 is using an MA PDU session including a 3GPP access path via a next generation radio access network (NG-RAN) and a non-3GPP access path via an N3IWF, the UE 10 may determine to switch the non-3GPP access path via the N3IWF to a non-3GPP access path via the TNGF. In this case, the N3IWF may correspond to the source access network 310, and the TNGF may correspond to the target access network 320. As another example, the UE 10 may receive a request from the 5G core network (e.g., SMF 130 and AMF 120) to switch one of the access paths using the MA PDU session. The case where the UE (10) or the 5G core network determines to switch the access path may include a case where the UE 10 performs a handover so that the non-3GPP access path is directly connected to the HPLMN via the TNGF, while the UE 10 uses an MA PDU session through an access path directly connected to the HPLMN by a 3GPP access through the N3IWF via the SNPN network and an access path connected to the HPLMN by a non-3GPP access.

Step 2: The UE 10 may send a registration request message to the target access network 320. The registration request message may include at least one of an indication notifying access path switching of the MA PDU session (e.g., an ATSSS switching indication) and a PDU session ID of the MA PDU session. The PDU session ID of the MA PDU session may be included in the PDU session list to be activated. The target access network 320 may receive the registration request message from the UE 10.

Step 3: The target access network 320 may select the same AMF 120 as the AMF 120 connected to the UE 10 so that the UE 10 uses the MA PDU session. For example, the target access network 320 may select the AMF 120 based on the registration request message received from the UE 10.

Step 4: The target access network 320 may send the registration request message received from the UE 10 to the AMF 120. The registration request message may include at least one of an indication notifying an access path switch of the MA PDU session (e.g., an ASSS switch indication) and a PDU session ID of the MA PDU session. The PDU session ID of the MA PDU session may be included in the PDU session list to be activated. The AMF 120 may receive the registration request message from the target access network 320.

Step 5: AMF 120 may determine whether the registration request message received in step 4 is a request for access path switching for an MA PDU session. For example, when AMF 120 receives an indication notifying access path switching for an MA PDU session and a list of PDU sessions to be activated, AMF 120 may determine that the indication is a registration request for access path switching for an MA PDU session. As another example, AMF 120 receives an indication notifying access path switching for an MA PDU session and/or a list of PDU sessions to be activated in a state where UE 10 has registered the access type of the source access network 310, AMF 120 may determine that the indication is a registration request for access path switching for an MA PDU session.

Step 6: AMF 120 may obtain user subscription data of UE 10 from UDM 170 and determine whether the user has subscribed to the access path switching function for the MA PDU session. In addition, AMF 120 may obtain user subscription data of UE 10 from UDM 170 and determine whether the user has subscribed to the function of switching between the same access types for access path switching for the MA PDU session.

Step 7: When AMF 120 determines in step 6 that the user has subscribed to the function of switching the access path of the MA PDU session and/or the function of switching between the same access types for access path switching of the MA PDU session, AMF 120 may send a PDU session update request message to SMF 130. The PDU session update request message may include an indication notifying the access path switching of the MA PDU session (e.g., an ASSS switching indication), the PDU session of the MA PDU session, the RAT type of the target access network, and the RAT type of the source access network. The PDU session ID of the MA PDU session may be included in the PDU session list to be activated. SMF 130 may receive the PDU session update request message from AMF 120.

Step 8: SMF 130 may send a response message to AMF 120 in response to the PDU session update request message. For example, the response message may include the time required for the access path switching (eg, the access path switching lifetime value).

Step 9: SMF 130 may start an access path switching timer corresponding to the time required for access path switching. When an MA PDU session is not successfully established via the target access network 320 before the access path switching timer expires, SMF 130 may determine that the access path has not been switched. For example, when AN tunnel information of the target access network 320 is successfully received before the access path switching timer expires, SMF 130 may determine that the access path has been successfully switched.

Step 10: AMF 120 may evaluate whether the registration request of UE 10 via the target access network 320 is valid, and may perform relevant procedures. AMF 120 may send a registration accept message to the target access network 320. The registration accept message may indicate the time required for the access path switch or the access path switch timer. For example, the time required for the access path switch or the access path switch timer value may be the same as or different from the time required for the access path switch received from SMF 130 in step 8. AMF 120 may prevent deregistration from starting when UE 10 establishes an MA PDU session via the target access network 320 and switches the access path. For example, AMF 120 may determine a value greater than the time required for the access path switch received from SMF 130 in step 8 as the access path switch timer value. The target access network 320 may receive a registration accept message from AMF 120.

Step 11: The target access network 320 may send the registration accept message received from the AMF 120 to the UE 10. The registration accept message may indicate the time required for the access path switch. The UE 10 may receive the registration accept message from the target access network 320.

Step 12: The AMF 120 may start a deregistration timer (e.g., a deregistration timer) corresponding to the time required to switch the determined access path. When the MA PDU session is not successfully established via the target access network 320, the AMF 120 may determine not to switch the access path until the registration deregistration timer expires. For example, when the AMF 120 receives a successful response to the N2 PDU session request message from the target access network 320 before the deregistration timer expires, the AMF 120 may determine that the access path has been successfully switched.

Step 13: The UE 10 may send a PDU session establishment request message to the AMF 120 via the target access network 320. The PDU session establishment request message may include an indication notifying that the message is for an MA PDU session (e.g., MA PDU request) and a PDU session ID of the MA PDU session. The PDU session establishment request message may include an indication notifying an access path switch for the MA PDU session (e.g., ASSS path switch indication). The AMF 120 may receive the PDU session establishment request message from the UE 10 via the target access network 320.

Step 14: AMF 120 may send an MA PDU session establishment request message requesting SMF 130 to establish an MA PDU session via the target access network 320. The MA PDU session establishment request message may include an indication notifying access path switching of the MA PDU session (e.g., ATSSS switching indication), a PDU session ID of the MA PDU session, the RAT type of the target access network, and the RAT type of the source access network. SMF 130 may receive the MA PDU session establishment request message from AMF 120.

The SMF 130 may send a response message in response to the MA PDU session establishment request message to the AMF 120. The SMF 130 may receive a response message from the AMF 120 in response to the MA PDU session establishment request message.

Step 15: SMF 130 may establish an SM policy association for the MA PDU session via PCF 140 and the target access network 320. For example, SMF 130 may establish an SM policy association for the MA PDU session via PCF 140 and the target access network 320 based on the MA PDU session establishment request message. The SM policy association for the MA PDU session via SMF 130 and the target access network 320 may be established by PCF 140.

Step 16: An N4 session for the MA PDU session via the UPF 110 and the target access network 320 may be established by the SMF 130. At this time, the SMF 130 and/or the UPF 110 may generate CN tunnel information for the target access network 320. For example, the CN tunnel information may include the IP address and port number of the UPF 110 for the N3 connection between the target access network 320 and the UPF 110.

Step 17: SMF 130 may send a Namf_Communication_N1N2Message transfer message to AMF 120. For example, the Namf_Communication_N1N2Message transfer message may include CN tunnel information for the target access network 320. AMF 120 may receive the Namf_Communication_N1N2Message transfer message from SMF 130.

The AMF 120 may send a response message in response to the Namf_Communication_N1N2Message transfer message to the SMF 130. The SMF 130 may receive a response message in response to the Namf_Communication_N1N2Message transfer message from the AMF 120.

Step 18: AMF 120 may send an N2 session request message to the target access network 320. The N2 session request message may include a PDU session accept message and CN tunnel information of the target access network 320. The target access network 320 may receive the N2 session request message from AMF 120.

Step 19: The target access network 320 may send an AN specific resource setup message requesting AN specific resource setup to the UE 10. The AN specific resource setup message may include a PDU session accept. The UE 10 may receive the AN specific resource setup message from the target access network 320.

Step 20: The target access network 320 may send an N2 session response message to the AMF 120. The target access network 320 may generate AN tunnel information of the target access network 320. For example, the AN tunnel information may include an IP address and a port number of the target access network 320 for the N3 connection between the target access network 320 and the UPF 110. The N2 session response message may include the AN tunnel information. The AMF 120 may receive the N2 session response message from the target access network 320.

Step 21: AMF 120 may send a Nsmf_PDUSession_UPdateSMContext request message to SMF 130. The Nsmf_PDUSession_UPdateSMContext request message may include AN tunnel information. SMF 130 may receive the Nsmf_PDUSession_UPdateSMContext request message from AMF 120.

Step 22: UE 10 may send uplink data to UPF 110 via target access network 320. UPF 110 may receive uplink data from UE 10 via target access network 320. UPF 110 may send uplink data received from UE 10 to DN 180. DN 180 may receive uplink data from UPF 110. UPF 110 may send downlink data to DN 180. UPF 110 may receive downlink data from DN 180. UPF 110 may send downlink data to UE 10 via target access network 320. UE 10 may receive downlink data from UPF 110 via target access network 320.

Step 23: When SMF 130 receives the AN tunnel information of the target access network 320 in step 21 and/or recognizes that the MA PDU session has been successfully established via the target access network 320, SMF 130 may determine the access path release with respect to the source access network 310.

Step 24: A MA PDU session release procedure using the access path with respect to the source access network 310 may be performed. The UE context and SM context associated with the MAPDU session using the access path may be deleted from the relevant NFs (UE 10, AMF 120, SMF 130, PCF 140, UDM 170, etc.). User plane resources associated with the MAPDU session using the access path with respect to the source access network 310 may be released.

Step 25: When the AMF 120 receives the AN tunnel information for the target access network 310 in step 20 and/or recognizes that the MA PDU session has been successfully established via the target access network 310, the AMF 120 may determine the deregistration of the UE 10 with respect to the source access network 310.

Step 26: A deregistration procedure of the UE 10 using the access path with respect to the source access network 310 may be performed. The UE context and AM context related to the registration of the UE 10 using the access path with respect to the source access network 310 may be deleted from the relevant NFs (UE 10, AMF 120, SMF 130, PCF 140, UDM 170, etc.). The RRC resources associated with the registration of the UE 10 using the access path with respect to the source access network 310 may be released.

In FIGS. 4A to 4D and 5A to 5D, a case where the UE 10 uses an untrusted non-3GPP access using N3IWF as a source access network 310 for non-3GPP access and uses a trusted non-3GPP using TNGF as a target access network 320 will be described as an example. However, the same/similar method can also be applied to access path switching between different types of non-3GPP accesses (or 3GPP access to non-3GPP access and vice versa), including cases where the source access network 310 = trusted non-3GPP access to the target access network 320 = untrusted non-3GPP access, etc.

4A to 4D illustrate a method for switching an access path of a UE 10 in a wireless communication system and a flowchart of a process related thereto according to an embodiment of the present disclosure.

Step 1: The UE 10 may perform a registration procedure for 3GPP access by using the NG-RAN 20. For example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may request an initial registration of a registration type, and the AMF 120 may determine the RAT type as NR. In addition, the AMF 120 may provide the UDM 170 with an AMF ID (e.g., GUAMI), 3GPP as an AN type, NR as a RAT type, and SUPI in a UECM registration procedure (a procedure for registering the AMF 120 in the UDM 170 as a serving NF for the UE 10).

Step 2: The UE 10 may perform a registration procedure for non-3GPP access by using the source access network 320. For example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may request an initial registration of a registration type, and the AMF 120 may determine the RAT type as untrusted non-3GPP. In addition, the AMF 20 provides the UDM 170 with the AMF ID (e.g., GUAMI), non-3GPP as AN type, untrusted non-3GPP as RAT type, and SUPI in a UECM registration procedure (a procedure for registering the AMF 120 in the UDM 170 as a serving NF for the UE 10).

Step 3a: The UE 10 may perform an MA PDU session establishment procedure for non-3GPP access by using the source access network 310. For example, when the UE 10 sends a PDU session establishment request to the AMF 120, the UE 10 may send at least one of an MA PDU request (e.g., the MA PDU request may be sent via a UL NAS transport message), a PDU session ID=PDU session ID-X, and an indication notifying a non-3GPP access path switch for the MA PDU session (e.g., an N3GPP path switch indication).

Step 3b: AMF 120 may determine whether AMF 120 supports non-3GPP access path switching and/or is capable of managing one or more UE registration states and one or more UE connection states of the same access type. When AMF 120 determines that AMF 120 cannot provide support, AMF 120 may reject the PDU session establishment request from UE 10.

The AMF 120 may select an SMF 130 that supports a non-3GPP access path switching function for an MA PDU session. When the AMF 120 is not allowed to select an SMF 130 that supports a non-3GPP access path switching function for an MA PDU session, the AMF 120 may reject a PDU session establishment request from the UE 10.

Step 3c: AMF 120 may request SMF 130 to generate a PDU session (e.g., AMF 120 may send a PDU session create SM context request message to SMF 130). AMF 120 may send at least one of a MA PDU request indication, an N3GPP path switch indication, a non-3GPP as an AN type, and an untrusted non-3GPP as a RAT type to SMF 130. When the MA PDU request indication is received in step 3a, AMF 120 may send the MA PDU request indication to SMF 130. When the N3GPP path switch indication is received in step 3a, AMF 120 may send the N3GPP path switch indication to SMF 130.

Step 3d: Continue to perform the process related to the MA PDU session establishment. The related process may include allocating and providing the UE's IP address for the user plane via the source access network 310, and/or CN tunnel information (UPF side N3 tunnel address), and/or AN tunnel information about the N3 tunnel connecting the source access network 310 and the UPF 110 (source access network 310 side N3 tunnel address (e.g., IP address, UDP port, etc.)).

Step 3e: When SMF 130 accepts the request for establishing an MA PDU session supporting the N3GPP path switching function, SMF 130 may send a UECM registration request to UDM 170 (a process of registering SMF 130 with UDM 170 as a serving NF for the current UE 10 and the current PDU session).

Step 3f: When the SMF 130 accepts the MA PDU session establishment request supporting the N3GPP path switching function, the SMF 130 may send an indication notifying the support of the N3GPP path switching function (e.g., supporting N3GPP path switching) to the AMF 120. For example, the supported N3GPP path switching may be included in the N1 SM container and included in the N1N2 message transfer message to be provided to the AMF 120.

Step 3g: AMF 120 may transmit a PDU Session Establishment Accept message including supported N3GPP path switching to UE 10.

Step 3h: Continue to perform the procedures related to the MA PDU session establishment. The related procedures may include the establishment of user plane resources for all access types currently registered by the UE 10 (for example, AN tunnel information, CN tunnel information and/or the IP address of the UE 10 allocated and provided via the corresponding access network may be included for the N3 tunnel). When step 3h is completed, the UE 10 can send and receive UL and/or DL data via the source access network 310.

Step 4: UE 10 may determine to switch one access path among the access paths using the MA PDU session. For example, UE 10 may determine to switch a non-3GPP access path that has been used via N3IWF to another non-3GPP access path via TNGF.

Step 5a: The UE 10 may perform a registration procedure for non-3GPP access by using the target access network 320. For example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may send at least one of an initial registration of a registration type, an N3GPP path switch indication, and a PDU session list to be activated including the PDU session ID-X used as the MA PDU session ID in step 3a. As another example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may send at least one of an N3GPP path switch and a PDU session list to be activated as a registration type, the PDU session list to be activated including the PDU session ID-X used as the MA PDU session ID in step 3a.

Step 6a: AMF 120 may request SMF 130 to update the MA PDU session (e.g., AMF 120 may send a PDU session update SM context request message to SMF 130). AMF 120 may send at least one of an MA PDU request indication, an N3GPP path switch indication, a PDU session ID=PDU session ID-X, non-3GPP as AN type, and a trusted non-3GPP as RAT type to SMF 130. When AMF 120 determines that the registration request in step 5a is a request for switching a non-3GPP access path for the MA PDU session (e.g., including a case where an N3GPP path switch indication is received in step 5a or a registration type=N3GPP path switch is received in step 5a), AMF 120 may send an N3GPP path switch indication to SMF 130.

Step 6b: SMF 130 may provide a response to the PDU session update request to AMF 120. When SMF 130 accepts the non-3GPP access path handover of the MA PDU session from the source access network 310 to the target access network 320, the process required for establishing user plane resources via the target access network 320 may be performed. For example, the process may include allocating and providing the UE's IP address, and/or CN tunnel information (UPF side N3 tunnel address) for the user plane via the source access network 310, and/or AN tunnel information about the N3 tunnel connecting the source access network 310 and UPF 110 (source access network 310 side N3 tunnel address (e.g., IP address, UDP port, etc.)). SMF 130 may provide user plane resource information to be provided to the target access network 320 to AMF 120 (e.g., may be included in the N2 SM container).

Step 6c: The AMF 120 may request the target access network 320 to establish user plane resources associated with the PDU session (e.g., an N2 PDU SESSION REQUEST or a PDU SESSION RESOURCE ESTABLISHMENT REQUEST message may be sent).

Step 6d: The procedures required for establishing user plane resources via the target access network 320 may be continuously performed by the AMF 120. For example, when the allocation and provision of the IP address of the UE 10 for the user plane via the target access network 320 is performed in step 6b, the allocation and provision may be transmitted to the AMF 120. When step 6d is completed, the AMF 120 may recognize that the SMF 130 has accepted the non-3GPP access path handover for the MA PDU session from the source access network 310 to the target access network 320.

Step 7: AMF 120 may inform UDM 170 that AMF 120 serves UE 10 via target access network 320. For example, AMF 120 may provide AMF ID (e.g., GUAMI), non-3GPP as AN type, trusted non-3GPP as RAT type, and SUPI to UDM 170 during UECM registration process.

Step 8: When the UDM 170 identifies in step 7 that the AMF 120 has performed a UECM registration of the same AN type (i.e., non-3GPP) with respect to the same UE 10 (i.e., in the case where it is identified in step 2 that the AMF has registered AN type = non-3GPP, RAT type = untrusted non-3GPP), the UDM 170 may notify the AMF 120 that the previous registration has been released (e.g., the UDM 170 may send a UECM deregistration notification message to the AMF 120). The UDM 170 may send at least one of SUPI, AN type = non-3GPP, RAT type = untrusted non-3GPP, PDU session ID = PDU session ID-X, and a deregistration cause to the AMF 120. N3GPP path switch may be provided to the deregistration cause.

Step 9a: AMF 120 may request the source access network 310 to release the UE context and/or release the AN connection. For example, AMF 120 may send an N2 UE context release command message to the source access network 310 and may provide N3GPP path switch as the cause.

Step 9b: The source access network 310 may request to release the AN connection to the UE 10. For example, the source access network 310 may perform a NWu connection release procedure.

After step 9 b , the UE 10 may buffer (or may also discard) UL traffic to be sent via the source access network 310 .

Step 9c: The source access network 310 may notify the AMF 120 that the release of the AN connection to the UE 10 has been completed. For example, the source access network 310 may send an N2 UE context release complete message to the AMF 120.

Step 9d: AMF 120 may provide a request to SMF 130 to release the non-3GPP access path of the source access network 310 via the MA PDU session. To this end, AMF 120 may request SMF 130 to update the MA PDU session (e.g., AMF 120 may send a PDU Session Update SM Context Request message to SMF 130). AMF 120 may send at least one of PDU Session ID=PDU Session ID-X, PDU Session Deactivation, Cause, Step Type=UP Deactivation, Non-3GPP as AN Type, and Untrusted Non-3GPP as RAT Type to SMF 130. AMF 120 may use a cause value indicating a release through a non-3GPP access path switch. For example, AMF 120 may use Cause=N3GPP Path Switch Indication.

Step 9e: A request to release user plane resources for the non-3GPP access path via the source access network 310 of the MA PDU session may be provided by the SMF 130. To this end, the SMF 130 may send an N4 session modification request to the UPF 110 (e.g., the SMF 130 may send an N4 session modification request to N4). The SMF 130 may provide the UPF 110 with an indication of the need to remove the AN tunnel information of the N3 tunnel of the untrusted non-3GPP access (an indication of the need to remove the tunnel information of the N3 tunnel of the untrusted AN non-3GPP access), the AN tunnel information of the untrusted non-3GPP access, and the CN tunnel information of the untrusted non-3GPP access.

The UPF 110 may buffer the DL traffic to be sent via the source access network 310 after step 9e (or may forward or discard the traffic to the SMF 130).

Step 9f: The process related to AN release of the non-3GPP access path via the source access network 310 may be continuously performed by the SMF 130. Releasing the session management policy related to the non-3GPP access path via the source access network 310 may be included in the related process.

Step 9g: A response to the user plane resource release request for the non-3GPP access path of the source access network 310 via the MA PDU session may be provided by the SMF 130 to the AMF 120.

Step 9h: AMF 120 may continuously perform procedures related to AN release of the non-3GPP access path via the source access network 310. Release of access and mobility management policies and/or UE policies related to the non-3GPP access path via the source access network 310 may be included in the relevant procedures.

Steps 9d to 9h (core network side user plane resource release and/or related policy release) may be performed before steps 9a to 9c and/or 9h (access network and UE 10 side user plane resource release and/or related policy release).

Step 10: AMF 120 may send a registration accept message to UE 10. AMF 120 may inform UE 10 that non-3GPP access path switching functionality is supported in the core network. For example, AMF 120 may send an N3GPP path switching support indication. Based on the indication, UE 10 may determine whether to allow a request for non-3GPP access path switching for the same or new MA PDU session.

Step 11a: The UE 10 may send all UL traffic of the source access network 310 to the UPF 110 via the target access network 320 .

Step 11b: The UPF 110 may send all DL traffic for the source access network 310 to the UE 10 via the target access network 320 .

5A to 5D show flowcharts of a method for switching an access path of a UE 10 in a wireless communication system and related processes according to an embodiment of the present disclosure.

Step 1: The UE 10 may perform a registration procedure for 3GPP access by using the NG-RAN 20. For example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may request an initial registration of a registration type, and the AMF 120 may determine the RAT type as NR. In addition, the AMF 120 may provide the UDM 170 with an ID (e.g., GUAMI) of the AMF 120, 3GPP as an AN type, NR as a RAT type, and SUPI in a UECM registration procedure (a procedure for registering the AMF 120 in the UDM 170 as a serving NF for the UE 10).

Step 2: The UE 10 may perform a registration procedure for non-3GPP access by using the source access network 310. For example, when the UE 10 sends a registration request to the AMF 120, the UE 10 may request an initial registration of a registration type, and the AMF 120 may determine the RAT type as untrusted non-3GPP. In addition, the AMF 120 may provide the UDM 170 with an AMF ID (e.g., GUAMI), non-3GPP as AN type, untrusted non-3GPP as RAT type, and SUPI in a UECM registration procedure (a procedure for registering the AMF 120 in the UDM 170 as a serving NF for the UE 10).

Step 3: The UE 10 may perform an MA PDU session establishment procedure for non-3GPP access by using the source access network 310. At this time, the UE 10 may not provide an indication notifying support for non-3GPP access path switching. For example, when the UE 10 sends a PDU session establishment request to the AMF 120, the UE 10 may send at least one of an MA PDU request (e.g., the MA PDU request may be sent via a UL NAS transport message) and a PDU session ID = PDU session ID-X. In this case, the AMF 120 and the SMF 130 may not determine whether the AMF 120 and the SMF 130 themselves support non-3GPP access path switching and/or are capable of managing one or more UE registration states and one or more UE connection states for the same access type.

When step 3 is completed, UE 10 can send and receive UL and/or DL data via source access network 310 .

Step 4: UE 10 may determine to switch one access path among the access paths using the MA PDU session. For example, UE 10 may determine to switch a non-3GPP access path that has been used via N3IWF to another non-3GPP access path via TNGF.

Step 5a: The UE 10 may perform a registration procedure for non-3GPP access by using the target access network 320. For example, when the UE 10 sends a registration request to the AMF 120, the UE may send at least one of an initial registration, an N3GPP path switch indication, and a PDU session list to be activated as a registration type, the PDU session list to be activated including the PDU session ID-X used as the MAPDU session ID in step 3. As another example, when the UE 10 sends a registration request to the AMF 120, the UE may send at least one of an N3GPP path switch and a PDU session list to be activated as a registration type, the PDU session list to be activated including the PDU session ID-X used as the MAPDU session ID in step 3.

Step 5b: AMF 120 may determine whether AMF 120 supports non-3GPP access path switching and/or is capable of managing one or more UE registration states and one or more UE connection states for the same access type. When AMF 120 determines that AMF 120 cannot provide support, AMF 120 may reject the PDU session establishment request from UE 10.

AMF 120 may determine whether SMF 130 supports the non-3GPP access path switching function of the MA PDU session. When SMF 130 does not provide support, AMF 120 may reject the PDU session establishment request from UE 10.

Regardless of whether the AMF 120 and/or SMF 130 supports the non-3GPP access path switching function for the MA PDU session, when support for the non-3GPP path switching function for the corresponding MA PDU session has not been identified (for example, it may include the case where the SMF 130 and/or AMF 120 has never received a PDU session establishment request including an N3GPP path switching indication for the corresponding MA PDU session). As another example, it may include the case where the SMF 130 and/or AMF 120 has never sent an N3GPP path switching support indication for the corresponding MA PDU session to the UE 10. As another example, it may include the case where the SMF 130 and/or AMF 120 has not sent an N3GPP path switching support indication for the corresponding MA PDU session and the UE 10. The AMF 120 may reject the PDU session establishment request from the UE 10. At this time, for the rejection reason, the AMF 120 may notify the UE 10 that the non-3GPP path switching function cannot be provided.

Step 6a: AMF 120 may request SMF 130 to update the MA PDU session (e.g., AMF 120 may send a PDU session update SM context request message to SMF 130). AMF 120 may send at least one of an MA PDU request indication, an N3GPP path switch indication, a PDU session ID=PDU session ID-X, non-3GPP as AN type, and a trusted non-3GPP as RAT type to SMF 130. When AMF 120 determines that the registration request in step 5a is a request for a non-3GPP access path switch for the MA PDU session (e.g., including the case where an N3GPP path switch indication is received in step 5a or a registration type=N3GPP path switch is received in step 5a), AMF 120 may send an N3GPP path switch indication to SMF 130.

Step 6b: SMF 130 may provide a response to the PDU session update request to AMF 120. When SMF 130 accepts the non-3GPP access path switch for the MA PDU session from the source access network 310 to the target access network 320, SMF 130 may perform the process required for establishing user plane resources via the target access network 320. For example, the process may include allocating and providing the UE's IP address, and/or CN tunnel information (UPF side N3 tunnel address), and/or AN tunnel information about the N3 tunnel connecting the target access network 320 and UPF 110 via the target access network 320 (target access network 320 side N3 tunnel address (e.g., IP address, UDP port, etc.)). SMF 130 may provide user plane resource information to be provided to the target access network 320 to AMF 120 (e.g., may be included in the N2 SM container).

Step 6e: When SMF 130 accepts the request for MA PDU session establishment supporting N3GPP path switching function, SMF 130 may send an indication notifying AMF 120 that N3GPP path switching function is supported (e.g., N3GPP path switching is supported). For example, the supported N3GPP path switching may be included in the N1 SM container and included in the N1N2 message transport message to be provided to AMF 120.

Step 6c: The AMF 120 may request the target access network 320 to establish user plane resources associated with the PDU session (e.g., the AMF 120 may send an N2 PDU SESSION REQUEST or a PDU SESSION RESOURCE ESTABLISHMENT REQUEST message).

Step 6d: The procedures required for establishing user plane resources via the target access network 320 may be continuously performed by the SMF 130. For example, when the allocation and provision of the IP address of the UE 10 for the user plane via the target access network 320 is performed in step 6b, the allocation and provision may be transmitted to the AMF 120. When step 6d is completed, the AMF 120 may recognize that the SMF 130 has accepted the non-3GPP access path handover of the MA PDU session from the source access network 310 to the target access network 320.

Step 7: AMF 120 may inform UDM 170 that AMF 120 serves UE 10 via target access network 320. For example, AMF 120 may provide AMF ID (e.g., GUAMI), non-3GPP as AN type, trusted non-3GPP as RAT type, and SUPI to UDM 170 during UECM registration process.

Step 8: When the UDM 170 identifies in step 7 that the AMF 120 has performed a UECM registration for the same AN type (i.e., non-3GPP) with respect to the same UE 10 (i.e., in the case where it is identified in step 2 that the AMF 120 has registered AN type = non-3GPP and RAT type = untrusted non-3GPP), the UDM 170 may notify the AMF 120 that the previous registration has been released (e.g., the UDM 170 may send a UECM deregistration notification message to the AMF 120). The UDM 170 may send at least one of SUPI, AN type = non-3GPP, RAT type = untrusted non-3GPP, PDU session ID = PDU session ID-X, and a deregistration cause to the AMF 120. N3GPP path switch may be provided to the deregistration cause.

Step 9a: AMF 120 may request the source access network 310 to release the UE context and/or release the AN connection. For example, AMF 120 may send an N2 UE context release command message to the source access network 310 and may provide N3GPP path switch as the cause.

Step 9b: The source access network 310 may request to release the AN connection to the UE 10. For example, the source access network 310 may perform a NWu connection release procedure.

After step 9 b , the UE 10 may buffer (or may also discard) UL traffic to be sent via the source access network 310 .

Step 9c: The source access network 310 may notify the AMF 120 that the release of the AN connection to the UE 10 has been completed. For example, the source access network 310 may send an N2 UE context release complete message to the AMF 120.

Step 9d: AMF 120 may provide a request to SMF 130 to release the non-3GPP access path via the source access network 310 of the MA PDU session. To this end, AMF 120 may request SMF 130 to update the MA PDU session (e.g., AMF 120 may send a PDU Session Update SM Context Request message to SMF 130). AMF 120 may send at least one of PDU Session ID=PDU Session ID-X, PDU Session Deactivation, Cause, Step Type=UP Deactivation, Non-3GPP as AN Type, and Untrusted Non-3GPP as RAT Type to SMF 130. AMF 120 may use a cause value indicating a release through a non-3GPP access path switch. For example, AMF 120 may use Cause=N3GPP Path Switch Indication.

Step 9e: A request to release user plane resources for the non-3GPP access path via the source access network 310 of the MA PDU session may be provided by the SMF 130. To this end, the SMF 130 may send an N4 session modification request to the UPF 110 (e.g., the SMF 130 may send an N4 session modification request to N4). The SMF 130 may provide the UPF 110 with at least one of an indication of the need to remove the AN tunnel information of the N3 tunnel of the untrusted non-3GPP access (an indication of the need to remove the AN tunnel information of the N3 tunnel of the untrusted non-3GPP access), the AN tunnel information of the untrusted non-3GPP access, and the CN tunnel information of the untrusted non-3GPP access.

The UPF 110 may buffer the DL traffic to be sent via the source access network 310 after step 9e (or may forward or discard the traffic to the SMF 130).

Step 9f: The process related to AN release of the non-3GPP access path via the source access network 310 may be continuously performed by the SMF 130. Releasing the session management policy related to the non-3GPP access path via the source access network 310 may be included in the related process.

Step 9g: A response to the user plane resource release request for the non-3GPP access path of the source access network 310 via the MA PDU session may be provided by the SMF 130 to the AMF 120.

Step 9h: The AMF 120 may continuously perform procedures related to the release of the non-3GPP access path via the source access network 310. The release of access and mobility management policies and/or UE policies related to the non-3GPP access path via the source access network 310 may be included in the relevant procedures.

Steps 9d to 9h (core network side user plane resource release and/or related policy release) may be performed before steps 9a to 9c and/or 9h (access network and UE 10 side user plane resource release and/or related policy release).

Step 10: AMF 120 may send a registration accept message to UE 10. AMF 120 may notify UE 10 that non-3GPP access path switching functionality is supported in the core network. For example, AMF 120 may send an N3GPP path switching support indication. Based on the indication, UE 10 may determine whether to allow a request for non-3GPP access path switching for the same or new MA PDU session.

Step 11a: The UE 10 may send all UL traffic of the source access network 310 to the UPF 110 via the target access network 320 .

Step 11b: The UPF 110 may send all DL traffic of the source access network 310 to the UE 10 via the target access network 320 .

FIG. 6 shows a UE 10 in a wireless communication system according to an embodiment of the present disclosure.

6, the UE 10 according to the present disclosure may include a controller 12 configured to control the overall operation of the UE 10, a transceiver 11 including a transmitter and a receiver, and a memory 13. The present disclosure is not limited to the above example, and the UE 10 may include more or less components than those shown in FIG6. The UE 10 may be referred to as a terminal.

According to the present disclosure, the transceiver 11 may transmit and receive signals to and from the network entities 20, 310, 320, 120, 130, 110, 140, 170, and 180 or other UEs. The signals transmitted to and received from the network entities 20, 310, 320, 120, 130, 110, 140, 170, and 180 may include control information and data. In addition, the transceiver 11 may receive signals via a wireless channel, output the signals to the controller 12, and transmit signals output from the controller 12 via a wireless channel.

According to the present disclosure, the controller 12 may control the UE 10 to perform the operations of FIGS. 3A to 5D described above. The controller 12, the memory 13, and the transceiver 11 may not necessarily be implemented as separate modules, but may also be implemented as a single component in the form of a single chip. In addition, the controller 12 and the transceiver 11 may be electrically connected to each other. In addition, the controller 12 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 13 may store data such as basic programs, applications, and configuration information for the operation of the UE 10. In particular, the memory 13 provides the stored data according to the request of the controller 12. The memory 13 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 13 may be provided. In addition, the controller 12 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 13.

FIG. 7 shows an NR-RAN 20 in a wireless communication system according to an embodiment of the present disclosure.

7 , the NR-RAN 20 according to the present disclosure may include a controller 22 configured to control the overall operation of the NR-RAN 20, a transceiver 21 including a transmitter and a receiver, and a memory 23. The present disclosure is not limited to the above example, and the NR-RAN 20 may include more or less components than those shown in FIG. 7 .

According to the present disclosure, the transceiver 21 may transmit and receive signals to and from the network entities 310, 320, 120, 130, 110, 140, 170, and 180 or the UE 10. The signals transmitted to and received from the network entities 310, 320, 120, 130, 110, 140, 170, and 180 may include control information and data. In addition, the transceiver 21 may receive signals via a wireless channel, output the signals to the controller 22, and transmit signals output from the controller 22 via the wireless channel.

According to the present disclosure, the controller 22 may control the NR-RAN 20 to perform the operations of FIGS. 3A to 5D described above. The controller 22, the memory 23, and the transceiver 21 may not necessarily be implemented as separate modules, but may also be implemented as a single component in the form of a single chip. In addition, the controller 22 and the transceiver 21 may be electrically connected to each other. In addition, the controller 22 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 23 may store data such as basic programs, applications, and configuration information for the operation of the NR-RAN 20. In particular, the memory 23 provides the stored data according to the request of the controller 22. The memory 23 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 23 may be provided. In addition, the controller 12 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 23.

FIG. 8 shows a source access network 310 in a wireless communication system according to an embodiment of the present disclosure.

8 , the source access network 310 according to the present disclosure may include a controller 312 configured to control the overall operation of the source access network 310, a transceiver 311 including a transmitter and a receiver, and a memory 313. The present disclosure is not limited to the above example, and the source access network 310 may include more or fewer components than those shown in FIG. 8 .

According to the present disclosure, the transceiver 311 may transmit and receive signals to and from at least one of the other network entities 20, 320, 120, 130, 110, 140, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 320, 130, 120, 130, 110, 140, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 312 can control the source access network 310 to perform the operations of Figures 3A to 5D above. The controller 312, the memory 313, and the transceiver 311 do not necessarily have to be implemented as separate modules, but can also be implemented as a single component in the form of a single chip. In addition, the controller 312 and the transceiver 311 can be electrically connected to each other. In addition, the controller 312 can be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 313 may store data such as basic programs, applications, and configuration information for the operation of the source access network 310. In particular, the memory 313 provides the stored data according to the request of the controller 312. The memory 313 may include a storage medium such as a ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. In addition, a plurality of memories 313 may be provided. In addition, the controller 312 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 313.

FIG. 9 shows a target access network 320 in a wireless communication system according to an embodiment of the present disclosure.

9 , the target access network 320 according to the present disclosure may include a controller 322 configured to control the overall operation of the target access network 320, a transceiver 321 including a transmitter and a receiver, and a memory 323. The present disclosure is not limited to the above example, and the target access network 320 may include more or fewer components than those shown in FIG. 9 .

According to the present disclosure, the transceiver 321 may transmit and receive signals to and from at least one of the other network entities 20, 310, 120, 130, 110, 140, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 120, 130, 110, 140, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 322 can control the target access network 320 to perform the operations of Figures 3A to 5D above. The controller 322, the memory 323, and the transceiver 321 do not necessarily have to be implemented as separate modules, but can also be implemented as a single component in the form of a single chip. In addition, the controller 322 and the transceiver 321 can also be electrically connected to each other. In addition, the controller 322 can be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 323 may store data such as basic programs, applications, and configuration information for the operation of the target access network 320. In particular, the memory 323 provides the stored data according to the request of the controller 322. The memory 323 may include a storage medium such as a ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. In addition, a plurality of memories 323 may be provided. In addition, the controller 322 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 323.

FIG. 10 shows an AMF 120 in a wireless communication system according to an embodiment of the present disclosure.

10 , the AMF 120 according to the present disclosure may include a controller 122 configured to control the overall operation of the AMF 120, a network interface 121 including a transmitter and a receiver, and a memory 123. The present disclosure is not limited to the above example, and the AMF 120 may include more or fewer components than those shown in FIG. 10 .

According to the present disclosure, the network interface 121 may transmit and receive signals to and from at least one of the other network entities 310, 320, 130, 110, 140, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 130, 110, 140, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 122 can control the AMF 120 to perform the operations of Figures 3A to 5D described above. The controller 122, the memory 123, and the network interface 121 do not necessarily have to be implemented as separate modules, but can also be implemented as a single component in the form of a single chip. In addition, the controller 122 and the network interface 121 can be electrically connected to each other. In addition, the controller 122 can be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 123 may store data such as basic programs, applications, and configuration information for the operation of the AMF 120. In particular, the memory 123 provides the stored data according to the request of the controller 122. The memory 123 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 123 may be provided. In addition, the controller 122 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 123.

FIG. 11 shows the SMF 130 in a wireless communication system according to an embodiment of the present disclosure.

11, the SMF 130 according to the present disclosure may include a controller 132 configured to control the overall operation of the SMF 130, a network interface 131 including a transmitter and a receiver, and a memory 133. The present disclosure is not limited to the above example, and the SMF 130 may include more or less components than those shown in FIG.

According to the present disclosure, the network interface 131 may transmit and receive signals to and from at least one of the other network entities 20, 310, 320, 120, 110, 140, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 120, 110, 140, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 132 may control the SMF 130 to perform the operations of FIGS. 3A to 5D described above. The controller 132, the memory 133, and the network interface 131 may not necessarily be implemented as separate modules, but may also be implemented as a single component in the form of a single chip. In addition, the controller 132 and the network interface 131 may be electrically connected to each other. In addition, the controller 132 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 133 may store data such as basic programs, application programs, and configuration information for the operation of the SMF 130. In particular, the memory 133 provides the stored data according to the request of the controller 132. The memory 133 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 133 may be provided. In addition, the controller 132 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 133.

FIG. 12 shows the UPF 110 in a wireless communication system according to an embodiment of the present disclosure.

12 , the UPF 110 according to the present disclosure may include a controller 112 configured to control the overall operation of the UPF 110, a network interface 111 including a transmitter and a receiver, and a memory 113. The present disclosure is not limited to the above example, and the UPF 110 may include more or less components than those shown in FIG.

According to the present disclosure, the network interface 111 may transmit and receive signals to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 112 may control the UPF 110 to perform the operations of FIGS. 3A to 5D described above. The controller 112, the memory 113, and the network interface 111 may not necessarily be implemented as separate modules, but may also be implemented as a single component in the form of a single chip. In addition, the controller 112 and the network interface 111 may be electrically connected to each other. In addition, the controller 112 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 113 may store data such as basic programs, application programs, and configuration information for the operation of the UPF 110. In particular, the memory 113 provides the stored data according to the request of the controller 112. The memory 113 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 113 may be provided. In addition, the controller 112 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 113.

FIG. 13 shows the PCF 140 in the wireless communication system according to an embodiment of the present disclosure.

13 , the PCF 140 according to the present disclosure may include a controller 142 configured to control the overall operation of the PCF 140, a network interface 141 including a transmitter and a receiver, and a memory 143. The present disclosure is not limited to the above example, and the PCF 140 may include more or less components than those shown in FIG.

According to the present disclosure, the network interface 111 may transmit and receive signals to and from at least one of the other network entities 20, 310, 320, 120, 130, 110, 170, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 120, 130, 110, 170, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 142 can control the PCF 140 to perform the operations of Figures 3A to 5D described above. The controller 142, the memory 143, and the network interface 141 do not necessarily have to be implemented as separate modules, but can also be implemented as a single component in the form of a single chip. In addition, the controller 142 and the network interface 141 can be electrically connected to each other. In addition, the controller 142 can be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 143 may store data such as basic programs, application programs, and configuration information for the operation of the PCF 140. In particular, the memory 143 provides the stored data according to the request of the controller 142. The memory 143 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 143 may be provided. In addition, the controller 142 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 143.

FIG. 14 illustrates a UDM 170 in a wireless communication system according to an embodiment of the present disclosure.

14 , the UDM 170 according to the present disclosure may include a controller 172 configured to control overall operations of the UDM 170, a network interface 171 including a transmitter and a receiver, and a memory 173. The present disclosure is not limited to the above examples, and the UDM 170 may include more or less components than those shown in FIG.

According to the present disclosure, the network interface 171 may transmit and receive signals to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 110, and 180 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 110, and 180 or the UE 10 may include control information and data.

According to the present disclosure, the controller 172 may control the UDM 170 to perform the operations of FIGS. 3A to 5D described above. The controller 172, the memory 173, and the network interface 171 may not necessarily be implemented as separate modules, but may also be implemented as a single component in the form of a single chip. In addition, the controller 172 and the network interface 171 may be electrically connected to each other. In addition, the controller 172 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 173 may store data such as basic programs, application programs, and configuration information for the operation of the UDM 170. In particular, the memory 173 provides the stored data according to the request of the controller 172. The memory 173 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 173 may be provided. In addition, the controller 172 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 173.

FIG. 15 shows a DN 180 in a wireless communication system according to an embodiment of the present disclosure.

15 , a DN 180 according to the present disclosure may include a controller 182 configured to control the overall operation of the DN 180, a network interface 181 including a transmitter and a receiver, and a memory 183. The present disclosure is not limited to the above examples, and the DN 180 may include more or fewer components than those shown in FIG. 15 .

According to the present disclosure, the network interface 181 may transmit and receive signals to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 110, and 170 or the UE 10. The signals transmitted and received to and from at least one of the other network entities 20, 310, 320, 120, 130, 140, 110, and 170 or the UE 10 may include control information and data.

According to the present disclosure, the controller 182 can control the DN 180 to perform the operations of Figures 3A to 5D described above. The controller 182, the memory 183, and the network interface 181 do not necessarily have to be implemented as separate modules, but can also be implemented as a single component in the form of a single chip. In addition, the controller 182 and the network interface 181 can be electrically connected to each other. In addition, the controller 182 can be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

According to the present disclosure, the memory 183 may store data such as basic programs, application programs, and configuration information for the operation of the DN 180. In particular, the memory 183 provides the stored data according to the request of the controller 182. The memory 183 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 183 may be provided. In addition, the controller 182 may execute the above-mentioned embodiments based on the program for executing the above-mentioned embodiments of the present disclosure stored in the memory 183.

Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims (15)

1. A method for a user equipment (UE) in a wireless communication system, the method comprising: Sending a registration request message including an access service steering, switching, splitting (ATSSS) path switching indication to a target access network; receiving, in response to the registration request message, from the target access network, a registration accept message including an access path switch timer value from the target access network; sending a packet data unit (PDU) session establishment request message to an access and mobility management function (AMF) via the target access network based on the access path switch timer value; and Release the PDU session with the source access network. 2. The method of claim 1, wherein the registration request message is sent by the target access network to the determined AMF. 3. The method of claim 2, wherein a registration accept message is sent from the AMF to the target access network. 4. The method of claim 3, wherein the registration accept message includes an access path switching timer value sent from a session management function (SMF) to the AMF based on the registration request message. 5. The method of claim 4, wherein, in a case where an access service steering, switching, splitting (ATSSS) path switch indication is used to support an ATSSS path switch for the UE, the access path switch timer value is sent from the SMF to the AMF. 6. A method of an access and mobility management function (AMF) in a wireless communication system, the method comprising: receiving a registration request message from a user equipment (UE) via a target access network, the registration request message including an access service steering, switching, splitting (ATSSS) path switch indication; In case the ATSSS path is switchable based on the registration request message, sending a packet data unit (PDU) session update request message indicating the ASSSS path switch indication, the radio access technology (RAT) type of the target access network, and the RAT type of the source access network to a session management function (SMF); In response to the PDU session update request message, receiving an update response message including an access path switching timer value from the SMF; Based on the update response message, sending a registration accept message including an access path switch timer value to the UE via the target access network; and In response to the REGISTER ACCEPT message, a PDU SESSION ESTABLISHMENT REQUEST message is received from the UE via the target access network. 7. The method according to claim 6 further includes: sending a PDU session creation request message to the SMF in response to the PDU session establishment request message. 8. The method of claim 7, wherein the PDU session creation request message includes an ATSSS path switch indication, a RAT type of the target access network, and a RAT type of the source access network. 9. The method of claim 6, further comprising: after sending the registration accept message, starting a deregistration timer based on an access path switching timer value. 10. The method of claim 9, comprising terminating the PDU session of the source access network in case a deregistration timer expires or access network (AN) tunnel information is received from the UE before the deregistration timer expires. 11. A method of a session management function (SMF) in a wireless communication system, the method comprising: receiving a packet data unit (PDU) session update request message from an access management function (AMF) indicating an ASSSS path switch indication of a user equipment (UE), a radio access technology (RAT) type of a target access network, and a RAT type of a source access network; In response to the PDU session update request message, send a PDU session update response message including the access path switch timer value to the AMF; receiving, in response to the PDU Session Update Response message, a PDU Session Create Request message from the AMF; and The PDU session of the UE with respect to the source access network is terminated based on the PDU session creation request message. 12. The method according to claim 11, wherein a PDU session update request message is sent from the AMF based on a registration request message sent from the UE to the AMF, and The registration request message includes an access service steering, switching, splitting (ATSSS) path switching indication. 13. The method of claim 11, wherein the PDU session creation request message includes an ATSSS path switch indication, a RAT type of the target access network, and a RAT type of the source access network. 14. The method of claim 11, further comprising: after sending the PDU session update response message, starting an access path switch timer based on an access path switch timer value. 15. The method of claim 14, comprising terminating the PDU session of the source access network when an access path switch timer expires or when access network (AN) tunnel information is received from the AMF before the access path switch timer expires.