Method and apparatus for configuring offload policy for VPLMN edge traffic in mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Specifically, a method and apparatus for efficiently configuring and applying policies associated with roaming user equipment (UE) when providing edge computing services via an HR session or an LBO session are disclosed.

Description

Technical Field

[0001] The present disclosure relates to a mobile communication system (or a radio communication system), and more particularly, to a method and an apparatus for configuring a policy to provide edge computing service information in a mobile communication system. Background Art

[0002] The fifth-generation (5G) mobile communication technology defines a wide frequency band, enabling high transmission rates and new services, and can be implemented not only in the "sub-6 GHz" frequency band such as 3.5 GHz, but also in the "above-6 GHz" frequency band called millimeter waves including 28 GHz and 39 GHz. In addition, in order to achieve a transmission rate 50 times faster than 5G mobile communication technology and an ultra-low latency of one-tenth of 5G mobile communication technology, it has been considered to implement 6G mobile communication technology (referred to as a super 5G system) in the terahertz (THz) frequency band (for example, 95 GHz to 3 THz frequency band).

[0003] In the initial stage of the development of 5G mobile communication technology, in order to support services and meet the performance requirements related to enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), standardization has been carried out on the following: beamforming and massive MIMO, used to mitigate radio wave path loss and increase the radio wave transmission distance in millimeter waves; support for parameter sets (for example, operating multiple subcarrier spacings), for efficient utilization of millimeter wave resources and dynamic operation of time slot formats; initial access technology, for supporting multi-beam transmission and broadband; the definition and operation of BWP (BandWidth Part, bandwidth part); new channel coding methods, such as LDPC (Low Density Parity Check) codes for large data transmission and polarization codes for highly reliable transmission of control information; L2 preprocessing; and network slicing, for providing a dedicated network dedicated to a specific service.

[0004] Currently, in view of the services that 5G mobile communication technology will support, discussions are underway regarding the improvement and performance enhancement of initial 5G mobile communication technology, and physical layer standardization of technologies such as V2X (Vehicle-to-everything), which is used to assist in autonomous vehicle driving determination based on information about the vehicle's location and status sent by the vehicle and to enhance user convenience; NR-U (New Radio Unlicensed), for system operation compliant with various regulatory requirements in the unlicensed frequency band; NR UE energy saving; Non-Terrestrial Network (NTN), which is UE-satellite direct communication for providing coverage in areas where communication with the terrestrial network is unavailable; and positioning.

[0005] In addition, standardization of technologies such as Industrial Internet of Things (IIoT), which is used to support new services through interoperability and integration with other industries; IAB (Integrated Access and Backhaul), for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner; mobility enhancement, including conditional handover and DAPS (Dual Active Protocol Stack) handover; and two-step random access, for simplifying the random access procedure (2-step RACH (Random Access Channel) for NR) has been underway in terms of air interface architecture / protocol. Standardization of the following has also been underway in terms of system architecture / services: 5G baseline architecture (e.g., service-based architecture or service-based interface), for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies; and Mobile Edge Computing (MEC), for receiving services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, the number of connected devices, which has been increasing exponentially, will be connected to communication networks. Accordingly, enhanced functions and performance of 5G mobile communication systems and integrated operation of connected devices are expected to be necessary. For this purpose, new research related to the following has been planned: Extended Reality (XR) to effectively support Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR), etc.; improving 5G performance and reducing complexity by leveraging Artificial Intelligence (AI) and Machine Learning (ML); AI service support; metaverse service support; and drone communication.

[0007] Furthermore, this development of 5G mobile communication systems will serve not only as a basis for developing new waveforms for covering the terahertz band for 6G mobile communication technologies, multi-antenna transmission technologies (such as Full Dimensional MIMO (FD-MIMO), array antennas, and massive antennas), metamaterial-based lenses and antennas for improving the coverage of terahertz band signals, high-dimensional spatial multiplexing technologies using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surfaces (RIS), but also as a basis for developing full-duplex technologies for improving the frequency efficiency of 6G mobile communication technologies and enhancing system networks, AI-based communication technologies for implementing system optimization by leveraging satellites and AI (artificial intelligence) from the design phase and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services with a complexity level exceeding the UE operation capacity limit by leveraging ultra-high-performance communication and computing resources.

[0008] With the development of communication systems, the demand for smoothly providing edge services to roaming User Equipment (UE) has increased.

[0009] The above information is presented as background technical information only to assist in understanding the present disclosure. No determination has been made, nor is any assertion made, as to whether any of the above can be considered prior art applicable to the present disclosure. Summary of the Invention

[0010] Solution to the Problem

[0011] To use edge computing services via a home routed (HR) session, a roaming user equipment (UE) may branch the corresponding session into a local data network (or a local access part of the data network) where an edge computing server of a visited network is installed.

[0012] In the case of an HR session, there is no defined method for interoperating with a home public land mobile network (HPLMN) and applying a roaming offloading policy (e.g., quality of service (QoS) and usage monitoring, etc.) associated with a branched session that diverges without the intervention of a policy control function (PCF) or a visited public land mobile network (VPLMN). Configuring policies to control QoS and usage monitoring, etc. associated with the branched session may be necessary for controlling network resources for serving roaming UEs and normal subscriber UEs.

[0013] In addition, even when a roaming UE uses edge computing services via a local break out (LBO) session, the roaming UE branches the LBO session and accesses the local data network (or a local access part of the data network). In this case, it is necessary to configure a roaming offloading policy associated with the branched session and control QoS and usage monitoring associated with the corresponding session.

[0014] Therefore, the present disclosure provides a method for efficiently configuring and applying a policy associated with a session of a roaming UE. Specifically, a method for configuring a policy to support roaming services via an HR session and an LBO session is provided. In addition, the present disclosure provides a method associated with a process in which a network entity (e.g., a session management function (SMF) entity) of a visited network obtains a roaming offloading policy and a process in which a PCF of a visited network or a home network generates / permits / corrects a session management policy for the corresponding HR session.

[0015] According to an embodiment of the present disclosure, a method performed by a first SMF entity of a home public land mobile network (HPLMN) is provided. The method includes: sending a first message for requesting an offloading policy of a visited public land mobile network (VPLMN) to a policy control function (PCF) entity of the HPLMN, the first message including information indicating that a protocol data unit (PDU) session of the VPLMN supports a home routed session branch (HR-SBO); and receiving a second message as a response to the first message from the PCF entity of the HPLMN, the second message including the offloading policy of the VPLMN based on the information.

[0016] According to an embodiment of the present disclosure, a method performed by a PCF entity in a mobile communication system, the method includes: receiving, from a first SMF entity of an HPLMN, a first message for requesting an offloading policy of a VPLMN, the first message including information indicating that a PDU session of the VPLMN supports HR-SBO; and sending, to the first SMF entity of the HPLMN, a second message as a response to the first message, the second message including an offloading policy of the VPLMN based on the information.

[0017] According to an embodiment of the present disclosure, a first SMF entity is provided. The first SMF entity includes: a transceiver; and a controller, coupled to the transceiver and configured to: send, to a PCF entity of an HPLMN, a first message for requesting an offloading policy of a VPLMN, the first message including information indicating that a PDU session of the VPLMN supports HR-SBO, and receive, from the PCF entity of the HPLMN, a second message as a response to the first message, the second message including an offloading policy of the VPLMN based on the information.

[0018] According to an embodiment of the present disclosure, a PCF entity is provided. The PCF entity includes: a transceiver; and a controller, coupled to the transceiver and configured to: receive, from a first SMF entity of an HPLMN, a first message for requesting an offloading policy of a VPLMN, the first message including information indicating that a PDU session of the VPLMN supports HR-SBO, and send, to the first SMF entity of the HPLMN, a second message as a response to the first message, the second message including an offloading policy of the VPLMN based on the information.

[0019] According to various embodiments of the present disclosure, the process of configuring and applying a roaming offloading policy required to provide edge computing services to a roaming UE can be efficiently performed. In addition, the network resources of the services provided to a normal UE and the services provided to a roaming UE can be dynamically and efficiently controlled via the roaming offloading policy.

[0020] Before proceeding with the following specific implementation manners, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: The terms "comprising" and "including" and their derivatives mean including but not limited to; the term "or" is inclusive and means and / or; the phrases "associated with" and "associated therewith" and their derivatives may mean including, being included within, interconnecting with, containing, being contained within, connected to or connecting with, coupled to or coupling with, capable of communicating with, cooperating with, interlacing, juxtaposing, adjacent to, bound to or binding with, having, having the property of, etc.; and the term "controller" refers to any device, system or part thereof that controls at least one operation, and such a device may be implemented in hardware, firmware or software or some combination of at least two of them. It should be noted that the functions associated with any particular controller may be centralized or distributed, whether local or remote.

[0021] In addition, the various functions described below may be implemented or supported by one or more computer programs, each formed of computer-readable program code and implemented 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, associated data or portions thereof adapted to be implemented 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 read only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD) or any other type of memory. A "non-transitory" computer-readable medium does not include wired, wireless, optical or other communication links that transmit transitory electrical or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and be rewritten later (such as rewritable optical discs or erasable storage devices).

[0022] This patent document also provides definitions for specific words and phrases throughout. Those of ordinary skill in the art should understand that in many, if not most, cases, such definitions apply to the prior and future use of the words and phrases so defined. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0024] Figure 1 illustrates a roaming scenario of a user equipment (UE) according to an embodiment of the present disclosure;

[0025] Figure 2 illustrates a process of configuring and applying a roaming offloading policy according to an embodiment of the present disclosure;

[0026] Figure 3 illustrates a process of configuring a user plane path based on a roaming offloading policy for edge computing services according to an embodiment of the present disclosure;

[0027] Figure 4 illustrates a process of configuring and applying a roaming offloading policy according to another embodiment of the present disclosure;

[0028] Figure 5 illustrates the structure of a UE according to an embodiment of the present disclosure;

[0029] Figure 6 illustrates the structure of a base station according to an embodiment of the present disclosure; and

[0030] Figure 7 illustrates the structure of a network function (or network entity) according to an embodiment of the present disclosure. Detailed Description of the Embodiments

[0031] The following discussion Figures 1 to 7 and the various embodiments used in this patent document to describe the principles of the present disclosure are merely exemplary and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0032] 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 drawings, the same or similar elements are denoted by the same or similar reference numerals as much as possible. In addition, detailed descriptions of known functions or configurations that may obscure the subject matter of the present disclosure will be omitted.

[0033] When describing the embodiments, descriptions related to technical content that is well known in the art and not directly related to the present disclosure will be omitted. The omission of such unnecessary descriptions is intended to prevent obscuring the main idea of the present disclosure and to more clearly convey the main idea.

[0034] For the same reason, in the drawings, some elements may be enlarged, omitted, or schematically shown. In addition, the size of each element does not fully reflect the actual size. In the drawings, the same or corresponding elements are provided with the same reference numerals.

[0035] Advantages and features of the present disclosure, as well as ways to implement them, will be clear by referring to embodiments described in detail below in conjunction with the accompanying drawings. 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 defined only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

[0036] In this context, it will be understood that each block of the flowchart illustration, and combinations of blocks in the flowchart illustration, 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 apparatus to produce a machine, such that the instructions executed via the processor of the computer or other programmable data processing apparatus create means for implementing the functions specified in one or more flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means for implementing the functions specified in one or more flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more flowchart blocks.

[0037] In addition, each block of the flowchart illustration can represent a module, segment, or portion of code that includes one or more executable instructions for implementing the specified one or more logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the functions involved.

[0038] As used herein, a "unit" refers to a software element or a hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, the meaning of a "unit" is not always limited to software or hardware. A "unit" can be configured to be stored in an addressable storage medium or executed by one or more processors. Thus, a "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, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" can be combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". In addition, the elements and "units" can be implemented as one or more CPUs within a reproducing device or a secure multimedia card. In addition, a "unit" in an embodiment can include one or more processors.

[0039] In the following description, for convenience of description, terms for identifying access nodes, terms for referring to network entities, terms for referring to messages, terms for referring to interfaces between network entities, terms for referring to various identification information, etc. are illustratively used. Thus, the present disclosure is not limited by the terms used below, and other terms referring to a subject having an equivalent technical meaning can be used.

[0040] In the following description, for convenience of description, terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) or New Radio (NR) standards will be used to describe the present disclosure. However, the present disclosure is not limited by these terms and names, and can be applied to systems conforming to other standards in the same manner.

[0041] In the following description, a base station (BS) is an entity that allocates resources to a terminal, and can be at least one of a radio access network (RAN) node, a gNode B (gNB), an eNode B (eNB), a Node B, a radio access unit, a base station controller, and a node on a network. 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".

[0042] In the following description, a terminal can 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, the examples of the base station and the terminal are not limited thereto.

[0043] In the present disclosure, for convenience of description, terms referring to network entities, network functions (NFs), network nodes, and edge computing system entities, terms referring to messages, terms referring to identification information, etc. are used illustratively. Accordingly, the present disclosure is not limited by the terms used below, and other terms referring to a subject having an equivalent technical meaning may be used. For example, in the following description, the term "terminal" may refer to a MAC entity in each terminal that exists for each of a master cell group (MCG) and a secondary cell group (SCG).

[0044] Specifically, the present disclosure may be applied to 3GPP NR (5th generation mobile communication standard). In addition, the present disclosure may be applied to intelligent services based on 5G communication technology and IoT-related technology (e.g., smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety-related services, etc.). The term "terminal" may refer to a mobile phone, an NB-IoT device, a sensor, and other wireless communication devices.

[0045] Wireless communication systems are evolving towards broadband wireless communication systems for providing high-speed and high-quality packet data services and typical voice-based 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)}, LTE-Advanced (LTE-A), LTE-Pro, High-Speed Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), IEEE 802.16e, etc.

[0046] 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) (eNode B), and the downlink indicates a radio link through which the base station transmits data or a control signal to the UE. The above multiple access scheme separates data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information for each user so as not to overlap with each other, i.e., to establish orthogonality.

[0047] Since the 5G communication system, which is a post-LTE communication system, must freely reflect various requirements of users, service providers, etc., it must 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.

[0048] According to an embodiment, eMBB aims to provide a data rate higher than that supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must provide a peak data rate of 20 Gbps in the downlink for a single base station and 10 Gbps 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. 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 20 MHz can be used in a frequency band of 3 to 6 GHz or 6 GHz or higher to obtain the data rate required for the 5G communication system, rather than using a transmission bandwidth of up to 20 MHz in a 2 GHz frequency band used in LTE to transmit signals.

[0049] In addition, mMTC is being considered to support application services such as the Internet of Things (IoT) in a 5G communication system. mMTC has requirements such as supporting the connection of a large number of UEs in a cell, enhanced coverage of UEs, increased battery time, and reduced cost of UEs to effectively provide the IoT. Since the IoT provides a communication function while being provided to various sensors and various devices, it must support a large number of UEs in a cell (e.g., 1,000,000 UEs / km2). In addition, UEs supporting mMTC may require a wider coverage range than that of other services provided by the 5G communication system because the UEs may be located in shadow areas (such as the basement of a building) that are not covered by the cell due to the nature of the service. UEs 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 replace the battery of the UE frequently.

[0050] Finally, URLLC, which is a cellular-based mission-critical wireless communication service, can be used for remote control of robots or machines, industrial automation, unmanned aerial vehicles, telemedicine, emergency alerts, etc. Therefore, URLLC must provide communication with ultra-low latency and ultra-high reliability. For example, a service supporting URLLC must meet an air interface latency of less than 0.5 ms and also require -5 a packet error rate of 10 or less. Therefore, for a service supporting URLLC, the 5G system must provide a transmission time interval (TTI) shorter than that of other services and may also require a design that allocates a large amount of resources in the frequency band to ensure the reliability of the communication link.

[0051] The above three services considered in the 5G communication system, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted in a single system. To meet the different requirements of each service, different transmission / reception techniques and transmission / reception parameters can be used between the services. However, the above mMTC, URLLC, and eMBB are only examples of different types of services, and the service types to which the present disclosure is applied are not limited to the above examples.

[0052] In the following description of embodiments of the present disclosure, LTE, LTE-A, LTE Pro, 5G (or NR), or 6G systems will be described by way of example, but the embodiments of the present disclosure can be applied to other communication systems having a similar background or channel type. In addition, based on the determination of those skilled in the art, the embodiments of the present disclosure can be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure.

[0053] In the following description of the present disclosure, for convenience of description, terms and names defined in the 5G system standard are used. However, the present disclosure is not limited by these terms and names and can be applied to systems conforming to other standards in the same manner.

[0054] Figure 1 A roaming scenario of a user equipment (UE) according to an embodiment of the present disclosure is shown. Figure 1 It is a diagram showing an example in an edge computing implementation scenario configured in the present disclosure, specifically, an example of an edge computing scenario without distinguishing layers.

[0055] A 5G system architecture supporting home routing (HR) roaming can include various network functions (NFs), and Figure 1 shows the access and mobility management function (AMF), session management function (SMF), policy control function (PCF), application function (AF), unified data management (UDM), data network (DN), user plane function (UPF), (radio) access network ((R)AN), and user equipment (UE) among various functions.

[0056] Each NF can support the following functions:

[0057] - The AMF provides access and mobility management functions based on the UE unit, and a single AMF can be accessed basically by a single UE. From the perspective of the UE subscriber, the visited AMF (V-AMF) is the AMF of the visited network. The home AMF (H-AMF) is the AMF of the home network of the UE subscriber;

[0058] - The DN can be, for example, an operator service, Internet access, or a third-party service, etc. The DN sends a downlink protocol data unit (PDU) to the UPF, or receives a PDU sent from the UE from the UPF;

[0059] - The PCF receives information associated with a packet flow from an application server and provides a function for determining policies associated with mobility management, session management, etc. Specifically, the PCF can support functions such as the following: supporting a unified policy framework to control network operations, providing policy rules for control plane functions (e.g., AMF, SMF, etc.) to implement the policy rules, and implementing a front end for accessing relevant subscription information to determine policies in the unified data repository (UDR);

[0060] - The SMF can provide session management functions, and in the case where the UE has multiple sessions, the sessions can be managed separately by different SMFs from each other. From the perspective of the UE subscriber, the V-SMF is the SMF of the visited network. The H-SMF is the SMF of the home network of the UE subscriber;

[0061] - The UDM stores user subscription data, policy data, etc.;

[0062] - The UPF transfers the downlink PDU received from the DN to the UE via the (R)AN, and transfers the uplink PDU received from the UE to the DN via the (R)AN; and / or

[0063] - The AF interoperates with the 3GPP core network to provide services (e.g., supporting functions such as the impact of an application on traffic routing, exposure of access network capabilities, and interoperating with a policy framework for policy control).

[0064] Figure 1 The network functions or network entities shown in can be some of the nodes included in the 5G core network, and the 5G core network can include a larger number of network functions or network entities than the example.

[0065] Figure 2 shows a process of configuring and applying a roaming offloading policy according to an embodiment of the present disclosure. Figure 2 is a diagram showing an embodiment of a process of generating and applying a roaming offloading policy for edge computing services.

[0066] Figure 2 The series of processes shown in are only examples for implementing the provided embodiments. That is, when implementing the provided processes according to the embodiments, at least one operation shown in can be omitted Figure 2 among the operations shown.

[0067] In an example of Operation 1, the UE sends a message to the AMF for requesting PDU session establishment. The message sent by the UE for requesting PDU session establishment may include at least one of a UE identifier, a PDU session identifier, a Home Public Land Mobile Network (HPLMN) single network slice selection assistance information (HPLMN S-NSSAI), a Visited Public Land Mobile Network (VPLMN) S-NSSAI, or a data network name (DNN) information, and the UE may provide this information to the AMF.

[0068] In an example of Operation 2, before receiving a PDU session establishment request from the UE (e.g., when performing the UE registration process), the AMF (i.e., the AMF of the VPLMN) may receive information from the UDM of the HPLMN related to whether a session branch of the HR roaming session is supported or allowed. Based on this, in the case where a HR session branch (HR-SBO) is available in association with the corresponding UE and the PDU session requested by the corresponding UE (or the DNN or S-NSSAI associated with the session establishment requested by the UE), the AMF may select a V-SMF that supports the same situation when selecting an SMF.

[0069] In an example of Operation 3, the AMF may send the information received from the UE and the HR session branch indication to the selected V-SMF, and a PDU session establishment SM context request message may be used for this sending. The HR session branch (HR-SBO) indication may be used to notify that the HR session branch is allowed or supported.

[0070] In an example of Operation 4, the V-SMF may send a response message to the AMF in response to Operation 3. The V-SMF may determine whether to perform the HR session branch according to local configuration. For example, the V-SMF may consider network resource conditions, network conditions, etc., as well as operator policies, etc., to determine whether to perform the HR session branch. The V-SMF may determine whether to perform the HR session branch and include information indicating the result associated with whether to perform the HR session branch in the response message sent to the AMF.

[0071] In an example of Operation 5, the V-SMF may select a V-UPF and establish an N4 session to configure an uplink path that can be connected to the HPLMN, and the configuration process may be performed via a process of sending and receiving N4 session establishment request / response messages. In the case where the HR session branch is allowed in Operation 4, the V-SMF may configure a user plane (UP) path that can be used as an uplink classifier (ULCL) or a branching point (BP).

[0072] In an example of operation 6, the V-SMF may send a PDU session creation request message including the information received from the AMF to the H-SMF. In the case where the V-SMF receives an HR session branch indication from the AMF and determines to perform HR session branching in the previous operation, the V-SMF may send an HR-SBO indication to the H-SMF. In the case where the V-SMF receives an HR session branch indication from the AMF, the V-SMF may provide the H-SMF with the aggregated maximum bit rate (AMBR) value applicable to the branch session of the HR branch in the VPLMN (e.g., HR-SBO session AMBR, AMBR of the session to the local part of the DN, or the highest session AMBR of the local part of the DN, or local session AMBR). The V-SMF may send the HR session branch specific AMBR value and the session AMBR value of the entire HR session (the maximum session AMBR value allowed in the VPLMN), HR session branch allowed VPLMN edge deployment information (fully qualified domain name (FQDN)), EAS IP range, data network name (DNN), S-NSSAI, and DN access identifier (DNAI). In addition, the PDU session establishment request message may include the information required to generate a roaming offloading policy (e.g., HR session branch allowed application information and HR session branch allowed FQDN information) in addition to the UE identifier, S-NSSAI, DNN, and AMBR of the session to the local part of the DN.

[0073] In an example of operation 7, the H-SMF may provide the UDM with the UE identifier, the VPLMN ID associated with the roaming performed by the UE, the HR session branch indication, DNN, S-NSSAI, etc., and may request the subscriber information of the roaming UE, and the process may be performed via the transmission of a subscriber information retrieval request message. Based on the information received from the V-SMF, the H-SMF may continue to establish a session and identify the roaming offloading policy to be applied to the session. For example, in the case where the H-SMF receives an HR session branch indication from the V-SMF, the H-SMF may consider the subscription information, the service policies configured in the H-SMF, etc. to determine whether the HR session branch is allowed and the roaming offloading policy (e.g., QoS and monitoring, charging related policies, HR session branch allowed application information, HR session branch allowed FQDN information, etc.).

[0074] In one example of operation 8, the UDM may provide to the H-SMF whether an HR session branch is allowed, and may provide HR session branch authorization information or indication, and may provide UE-related subscriber information and roaming offload policies. This process may be performed via the process of sending a response message to the request message in operation 7 (depending on the situation, the information stored in the UDR may be retrieved and provided). For example, associated with the UE and PDU session (or DNN and S-NSSAI) for which the request is being executed, the UDM may send to the H-SMF whether an HR session branch is allowed, associated with the VPLMN ID for which it is performing roaming and the AMBR associated with the branch session from the HR branch (e.g., the AMBR of the subscribed session of the local part of the DN or the AMBR value of the subscribed session of the local part of the DN). In addition, the UDM may provide to the H-SMF HR roaming session branch-related monitoring, charging-related policies, HR session branch allowed application information, HR session branch allowed FQDN information, HR session branch allowed IP address range, etc., as roaming offload policies.

[0075] In the case of the UDM and UDR, whether an HR roaming session branch is allowed and the roaming offload policy may be configured for each VPLMN ID. In addition, whether an HR roaming session branch is allowed and the roaming offload policy information may be configured to be different for each DNN and S-NSSAI. For example, the information associated with whether an HR roaming session branch is allowed and the roaming offload policy may be configured for each combination of PLMN ID, DNN, and S-NSSAI. The roaming offload policy may include values such as the AMBR of the subscribed session of the local part of the DN, the total volume threshold of the subscribed data traffic of the local part of the DN, etc.

[0076] In one example of operation 9, based on the HR session branch authorization information or indication associated with the corresponding VPLMN obtained from the UDM, the H-SMF may determine that the HR session branch is allowed and may determine the relevant policy information. For example, the H-SMF may determine the AMBR of the session of the local part of the DN to be actually applied by considering the AMBR of the session of the local part of the DN supported in the VPLMN received from the V-SMF and the AMBR of the subscribed session of the local part of the DN obtained from the UDM. In addition, the determination may be made in association with HR session branch allowed application information, HR session branch allowed FQDN information, HR session branch allowed IP address range, etc. The H-SMF may make the determination directly without using the H-PCF.

[0077] In one example of operation 10, the H-SMF may select an H-PCF that can provide HR session branch-related policy information or roaming offload policy information for the roaming UE.

[0078] In one example of operation 11, the H-SMF may send to the H-PCF the HR session branch permission information / indication obtained from the UDM and the V-SMF, the VPLMN ID, the DNN / S-NSSAI, and the policy-related information (such as the AMBR of the session of the local part of the DN, the VPLMN edge deployment information, etc.), and may request the HR session branch-related policy or the roaming offload policy information.

[0079] In one example of operation 12, the H-PCF may provide session policies (such as roaming offloading policies) to be applied to the VPLMN and HPLMN respectively by considering the information received from the H-SMF (VPLMN ID, QoS information, etc., such as the AMBR of the session of the local part of the DN provided by the V-SMF, and the subscribed session AMBR of the local part of the DN provided by the H-SMF) and the relevant information obtained from the UDR (for example, for each of the HPLMN and VPLMN, information associated with the charging function address, charging method, subscriber category, usage monitoring information, usage monitoring key, monitoring start and end dates, total traffic limit, traffic usage time limit, etc. may be stored in the UDR, and the H-PCF may use the VPLMN ID received from the H-SMF and may obtain the roaming session-related policy-related information to be applied to the VPLMN and the policy-related information to be applied to the HPLMN). For example, as a roaming offloading policy, the H-PCH may provide the authorized AMBR of the session of the local part of the DN, the HR session branch-related monitoring policy, the HR session branch allowed application information, the HR session branch allowed FQDN information, etc. to the H-SMF. The H-PCF may distinguish this information into information mapped to the VPLMN ID (such as the SM policy association ID) and information to be applied to the HPLMN, and may provide it to the H-SMF (the authorized AMBR of the session of the local part of the DN, the HR session allowed application and FQDN information, etc. may be mapped to the VPLMN ID and may be provided). In addition, the H-PCF may provide the foregoing information to the H-SMF by mapping the charging information (for example, charging key, charging function ID, charging function address, application service provider ID, charging method (such as online or offline scheme), measurement scheme (total data volume, duration, combined total volume / duration, etc.)) and the usage monitoring information (for example, monitoring key, total threshold, time threshold, monitoring time), the AF-affected traffic steering enforcement control information, etc. to each PLMN ID (i.e., by identifying based on the PLMN ID), and this information is different for each of the HPLMN and VPLMN. A policy control request trigger associated with each PLMN may also be defined and provided.

[0080] In an example of operation 13, the H-SMF may select an H-UPF based on the information received from the H-PCF and the information received from the V-SMF, and may configure the H-UPF with the policies to be applied to the HPLMN (the policies mapped to the HPLMN ID in the policies received in the previous operation). This process may be performed by establishing an N4 session between the H-SMF and the H-UPF. For example, the H-SMF may configure the session AMBR of the entire HR for the H-UPF, and the H-UPF may monitor and apply the session AMBR for the DL.

[0081] In an example of operation 14, the H-SMF may send the HR session-related roaming offloading policy information received from the H-PCF to the V-SMF, and this process may be performed by sending a PDU session creation request message. Without the intervention of the H-PCF, the H-SMF may provide the roaming offloading policy determined in operation 9 based on the information obtained from the V-SMF and the UDM. The information sent by the H-SMF to the V-SMF may include at least one of the following items of information:

[0082] - HR session branch authorization information (including information / indication indicating whether it is allowed or not);

[0083] - AMBR of the session of the local part of the DN (in the presence of information provided by the H-PCF or information determined by the H-SMF and information provided by the H-PCF, the value provided by the H-PCF is preferably used) (for reference: provided only when the HR session branch is allowed);

[0084] - Session AMBR;

[0085] - HR session branch allowed application information (application identifier or IP address information, IP address range information);

[0086] - HR session branch allowed FQDN information, IP address range (for reference: provided only when the HR session branch is allowed); and / or

[0087] - Monitoring and charging-related information: Information to be applied to the branch HR session (for reference: provided only when the HR session branch is allowed) and information to be applied to the entire HR session are distinguished and provided as two types of policy information (e.g., charging key, charging function ID, charging function address, application service provider ID, charging method (e.g., online or offline scheme), measurement scheme (total data volume, duration, combined total volume / duration, etc.), monitoring key, total volume threshold, time threshold, monitoring time, etc.).

[0088] - UE IP address (IPv4 or IPv6 address information)

[0089] In one example of operation 15, the V-SMF may determine whether an HR session branch is permitted based on information received from the H-SMF, may update the information configured for the V-UPF in operation 5, and the process may be performed via, for example, the sending or receiving of N4 session correction request / response messages. For example, in the case where the HR session branch is identified as permitted based on the HR session branch authorization information provided by the H-SMF, a UPF to be used as an uplink classifier (ULCL) or a bifurcation point (BP) may be selected, and a roaming offloading policy related to the local part of the DN received from the H-SMF (e.g., the AMBR of the session of the local part of the DN) and a policy to be applied to the entire HR session (e.g., session AMBR) may be configured.

[0090] In one example of operation 16, the V-SMF may send policy information that needs to be configured for the UE and the RAN to the AMF. For example, information associated with QoS rules, UE IP address, session AMBR, and the AMBR of the session of the local part of the DN may be provided.

[0091] In one example of operation 17, the AMF may send a PDU session identifier, a PDU session establishment permission message, session AMBR, the AMBR of the session of the local part of the DN, QoS rules, QoS flow level QoS parameters, UE IP address (IPv4), etc. to the RAN and the UE. Based on the information received from the AMF, the UE and the RAN may perform RRC configuration, and the session AMBR policy may be applied in the uplink by using the AMBR value of the session of the local part of the DN and the session AMBR value.

[0092] In one example of operation 18, the AMF may provide the user plane resource setting information configured in the RAN to the V-SMF.

[0093] In one example of operation 19, the V-SMF may configure the connection to the RAN for the V-UPF.

[0094] In one example of operation 20, the V-SMF may send a response message to the AMF in response to operation 18.

[0095] After completing the process described with reference to Figure 2 or when performing these processes, the V-SMF may add a UPF acting as an uplink classifier or a bifurcation point based on the information received from the H-SMF, and may configure the UP path for supporting edge services. The operations will be described in detail with reference to the Figure 3 following.

[0096] Figure 3Illustrates a process of configuring a user plane path based on a roaming offloading strategy for edge computing services according to an embodiment of the present disclosure. Figure 3 Describes a process of configuring a UP path based on an edge computing service roaming offloading strategy.

[0097] In one example of operation 1a, the UE, V-SMF, and H-SMF can interoperate and can establish (or set up) a PDU session for HR roaming.

[0098] In one example of operation 1b, the V-SMF and H-SMF can configure the V-UPF3 and H-UPF that are respectively connected to the VPLMN and HPLMN. The H-SMF can configure the session AMBR (i.e., DL session AMBR) associated with the entire HR session for the H-UPF. In addition, the H-SMF can send configuration information to the V-SMF to configure the session AMBR for the UE, the UPF (e.g., V-UPF2) serving as the PDU session anchor point (PSA) in the VPLMN, and the UPF (e.g., V-UPF1) serving as the uplink classifier or bifurcation point. In addition, in the case where the AMBR of the local part of the DN for the session is configured, the H-SMF can send the AMBR of the local part of the DN for the session to the V-SMF to configure the AMBR of the local part of the DN for the session for the UE, RAN, and the UPFs (e.g., V-UPF1 serving as the uplink classifier or bifurcation point and V-UPF2 serving as the PSA of the local part of the DN) that can be added.

[0099] In one example of operation 2, the V-SMF can configure Domain Name System (DNS) query message handling rule information in the visited edge application server discovery function (V-EASDF), and the process can be executed via the transmission of a DNS context creation message. The DNS query message handling rule information can include UE address, DNN / S-NSSAI, DNS message detection and action information (FQDN range, EAS IP range, ECS option, local DNS service IP address), etc.

[0100] In one example of operation 3, the UE can send the DNS query received from the V-SMF to the V-EASDF.

[0101] In one example of operation 4, the V-EASDF can interoperate with the DNS server and can obtain the EAS address in response to the DNS query message from the UE.

[0102] In one example of operation 5, the V-EASDF can send a DNS context notification including the obtained EAS address to the V-SMF.

[0103] In an example of operation 6, the V-SMF may perform ULCL / BP insertion considering the EAS address received from the V-EASDF. In this case, the V-SMF may select the V-UPF2 and may configure it as the local PDU session anchor (L-PSA), and the V-SMF may configure the V-UPF2 with the policies received from the H-SMF. For example, the V-SMF may configure the V-UPF2 with the session AMBR received from the H-SMF associated with the entire HR roaming session, and roaming offloading policies such as the AMBR for the session of the local part of the DN, usage monitoring rules, usage thresholds, etc. In addition, the V-SMF may select the V-UPF1 and may configure it as an uplink classifier or a bifurcation point. In addition, the V-SMF may configure the V-UPF1 configured as a ULCL or a bifurcation point with the session AMBR (UL session AMBR) received from the H-SMF associated with the entire HR roaming session, such that the V-UPF1 may operate according to the configuration.

[0104] In an example of operation 7, the V-SMF may provide DNS message handling rules to the EASDF, and the EASDF may provide guidance associated with handling the DNS queries of the UE. This process may be performed according to the DNS context update process.

[0105] In an example of operation 8, the V-EASDF may send a DNS response including EAS address information to the UE according to the DNS message handling rules provided by the V-SMF.

[0106] In an example of operation 9, the UE together with the RAN may apply the UL session AMBR received from the V-SMF (provided by the H-SMF and received via the V-SMF) and the AMBR for the UL session of the local part of the DN. The UE may apply the UL session AMBR to the traffic of the entire HR roaming session, and may apply the AMBR for the UL session of the local part of the DN to the traffic sent to the local part of the DN in the VPLMN. To apply the AMBR for the UL session of the local part of the DN, the UE may distinguish the traffic sent to the local part of the DN by using the destination traffic information (5-tuple or application identifier or application client identifier) or IPv6 prefix, etc., and may apply the AMBR for the session of the local part of the DN.

[0107] The V-UPF1 acting as an uplink classifier or a bifurcation point may perform the enforcement of the UL session AMBR configured by the V-SMF, and may perform usage monitoring for the local part of the DN and the entire HR session.

[0108] The V-UPF 2 acting as the local part of the DN can enforce the DL session AMBR configured by the V-SMF and the AMBR of the DL session of the local part of the DN, and can perform usage monitoring for the local part of the DN.

[0109] In addition, the H-UPF can enforce the DL session AMBR and perform usage monitoring for the HR roaming session configured by the H-SMF.

[0110] Figure 2 and Figure 3 The operation in which the H-SMF provides the roaming offload policy information included in the subscriber information via interoperability with the UDM and provides the allowable policy information in the VPLMN obtained from the V-SMF to the H-PCF and the operation of obtaining the finally authorized roaming offload policy from the H-PCF can be performed when establishing the PDU session, or can be performed during the PDU session correction process after establishing the PDU session.

[0111] In addition, the H-SMF can obtain the edge deployment information in the VPLMN from the V-SMF to generate a roaming offload policy to be applied in the VPLMN. This information can be pre-configured in the H-SMF, or this information can be obtained via the H-NEF. In addition, the H-SMF can determine the roaming offload policy based on the autonomously configured information without interoperating with the H-PCF, and can provide it to the V-SMF. For example, in a network that does not use the H-PCF, the H-SMF can configure the roaming offload policy based on the UDM or the autonomously configured information.

[0112] Figure 4 The process of configuring and applying the roaming offload policy according to another embodiment of the present disclosure is shown.

[0113] In an example of operation 1, the UE sends a message for requesting PDU session establishment to the AMF. The message for requesting PDU session establishment sent by the UE may include at least one of a UE identifier, a PDU session identifier, single network slice selection assistance information (HPLMN S-NSSAI), VPLMN S-NSSAI, or a data network name (DNN), and the UE can provide this information to the AMF.

[0114] In an example of operation 2, the AMF (i.e., the AMF of the VPLMN) may select a V-SMF that is capable of performing session management for the corresponding UE and the PDU session requested by the corresponding UE (or the DNN or S-NSSAI associated with the session establishment requested by the UE). For example, a V-SMF that is capable of performing the local breakout (i.e., the LBO session) associated with the roaming UE or a V-SMF that is capable of configuring a UPF that serves as the ULCL or BP for the LBO and the LBO session.

[0115] In an example of operation 3, the AMF may send the information received from the UE and the information indicating that the establishment of the LBO session is allowed to the selected V-SMF, and a PDU session creation (or establishment) SM context request message may be used for such sending.

[0116] In an example of operation 4, the V-SMF may provide the UE identifier, the VPLMN ID associated with the roaming performed by the UE, the DNN, the S-NSSAI, etc. to the UDM, and may request the subscriber information of the roaming UE, and this process may be performed via the transmission of a subscriber information retrieval request message. Based on the information received from the AMF, the V-SMF may continue to establish the session and identify the roaming offloading policy to be applied to the session.

[0117] In one example of operation 5, the UDM may provide the V-SMF with information associated with whether LBO is allowed, and may provide UE-related subscriber information associated with VPLMN roaming and a roaming offloading policy associated with the corresponding PDU session (or associated with the DNN and S-NSSAI), and this process may be performed via the transmission of a response message in response to the request message in operation 4 (e.g., the UDM may retrieve the information stored in the UDR and provide it to the V-SMF). For example, associated with the UE and PDU session (or DNN and S-NSSAI) for which the request is being executed, the UDM may send to the V-SMF whether LBO is allowed, associated with the VPLMN ID for which roaming is being performed and the AMBR associated with the branch session branched from the LBO session (e.g., the subscribed session AMBR of the local part of the DN or the AMBR value of the subscribed session of the local part of the DN). In addition, the UDM may provide the V-SMF with usage monitoring of the session of the local part of the DN of the LBO roaming session, a charging-related policy for the local part of the DN of the LBO roaming session, application information allowing the LBO roaming session to branch to the local part of the DN, FQDN information allowing the LBO roaming session to branch to the local part of the DN, an IP address range allowing the LBO roaming session to branch to the local part of the DN, etc. as the roaming offloading policy. The session of the local part of the DN of the LBO roaming session may be a branch session branched from the LBO roaming session via a UPF that acts as an uplink classifier or a bifurcation point for supporting the edge computing service of the VPLMN. For the UDM and UDR, the LBO allowance information and the roaming offloading policy may be configured for each VPLMN ID. In addition, whether LBO is allowed and the roaming offloading policy information may be configured to be different for each DNN and S-NSSAI.

[0118] In one example of operation 6, the V-SMF may send a PDU session establishment response message to the AMF in response to operation 3.

[0119] In one example of operation 7, the V-SMF may select a V-PCF that can provide LBO session-related policy information or roaming offloading policy information for the roaming UE. For example, the V-PCF may select using the UE's HPLMN ID, DNN, and S-NSSAI. The V-SMF may send the LBO session allowance information / indication, HPLMN ID, DNN / S-NSSAI, and policy-related information obtained from the UDM to the selected V-PCF and may request LBO session-related policy or roaming offloading policy information.

[0120] In an example of operation 8, the V-PCF may consider the information received from the V-SMF (HPLMN ID, QoS information, such as the AMBR of the session of the local part of the DN provided by the V-SMF, etc., and the subscribed AMBR of the session of the local part of the DN provided by the V-SMF) and the relevant information obtained from the UDR [e.g., charging function address, charging method, subscriber category, usage monitoring information of the session of the local part of the DN for the LBO roaming session (usage monitoring key, monitoring start and end dates, total traffic limit, traffic usage time limit, etc.), charging-related policies for the local part of the DN of the LBO roaming session, application information allowing the LBO roaming session to branch to the local part of the DN, FQDN information allowing the LBO roaming session to branch to the local part of the DN, IP address range allowing the LBO roaming session to branch to the local part of the DN], and provide the session policies (roaming offloading policies, etc.) to be applied to the VPLMN and HPLMN to the V-SMF respectively. For example, as a roaming offloading policy, the V-PCF may provide the authorized AMBR of the session of the local part of the DN, the monitoring policy related to the LBO session branch, the application information of the session of the local part of the DN allowing the LBO roaming session, the FQDN information of the session of the local part of the DN allowing the LBO roaming session, etc. to the V-SMF. The V-PCF may distinguish this information (such as the SM policy association ID) as policy information associated with a normal LBO session and the information to be applied to the session of the local part of the DN of the LBO roaming session (by using the DNAI or the indicator of the session of the local part of the DN, etc.), and may provide it to the V-SMF (the authorized AMBR of the session of the local part of the DN, the application and FQDN information of the session of the local part of the DN allowing the LBO roaming session, etc. may be mapped to the DNAI or the indicator of the session of the local part of the DN and may be provided). In addition, the V-PCF may provide charging information [charging key, charging function ID, charging function address, application service provider ID, charging method (online or offline scheme), measurement scheme (total data volume, duration, combined total volume / duration, etc.)], usage monitoring information [monitoring key, total threshold, time threshold, and monitoring time], AF-affected traffic steering enforcement control information, etc., which are different for each of the normal LBO session and the session of the local part of the DN of the LBO roaming session. A policy control request trigger associated with each of the normal LBO session and the session of the local part of the DN of the LBO roaming session may also be defined and provided.

[0121] In an example of operation 9, based on the information received from the V-PCF, the V-SMF may select the V-EASDF and configure the DNS context, and may select the V-UPF and may configure the roaming offloading policy. The operation of configuring the V-UPF may be performed via the N4 session establishment procedure. The information sent by the V-SMF to the V-UPF may include at least one of the following:

[0122] - The AMBR of the local part of the DN;

[0123] - The session AMBR;

[0124] - Application information (application identifier or IP address information, IP address range information) of the session of the local part of the DN that allows LBO roaming sessions;

[0125] - FQDN information of the session of the local part of the DN that allows LBO roaming sessions, IP address range (for reference: provided only when the HR session branch is allowed);

[0126] - Monitoring and charging related information: Information to be applied to the branch LBO session and information to be applied to the entire LBO session may be distinguished and provided as two types of policy information. [For example, charging key, charging function ID, charging function address, application service provider ID, charging method (online or offline scheme), measurement scheme (total data volume, duration, combined total volume / duration, etc.), monitoring key, total volume threshold, time threshold, and monitoring time]; and

[0127] - UE IP address (IPv4 or IPv6 address information).

[0128] In an example of operation 10, the V-SMF may send the policy information that needs to be configured for the UE and the RAN to the AMF. For example, the V-SMF may provide the AMF with information associated with QoS rules, UE IP address, session AMBR, and the AMBR of the local part of the DN's session.

[0129] In an example of operation 11, the AMF may send the PDU session identifier, PDU session establishment permission message, session AMBR, the AMBR of the local part of the DN's session, QoS rules, QoS flow level QoS parameters, UE IP address (IPv4), etc. to the RAN and the UE. Based on the information received from the AMF, the UE and the RAN may perform RRC configuration and may enforce the session AMBR policy in the uplink by using the AMBR value of the local part of the DN's session and the session AMBR value. The AMF may provide the V-SMF with the user plane resource setting information configured in the RAN.

[0130] In one example of operation 12, the V-SMF may add a UPF that serves as an uplink classifier or a bifurcation point, and may connect to the V-UPF. A session path may be configured in which the transmission to the local part of the DN is performed via the UPF that serves as an uplink classifier or a bifurcation point. The V-SMF may configure the UPF that serves as an uplink classifier or a bifurcation point with the session AMBR for the entire LBO roaming session received from the V-PCF and the following information as a roaming offloading policy, such as the AMBR for the session of the local part of the DN, usage monitoring rules, usage thresholds, etc.:

[0131] - AMBR of the local part of the DN (when information provided by the H-PCF or information determined by the H-SMF and information provided by the H-PCF exist, the value provided by the H-PCF is preferably used) (for reference: provided only when the HR session branch is allowed);

[0132] - Session AMBR;

[0133] - Application information (application identifier or IP address information, IP address range information) of the session of the local part of the DN that allows the LBO roaming session;

[0134] - FQDN information and IP address range of the session of the local part of the DN that allows the LBO roaming session (for reference: provided only when the HR session branch is allowed); and / or

[0135] - Monitoring and charging related information: Information to be applied to the branched LBO session and information to be applied to the entire LBO session may be distinguished and provided as two types of policy information. [For example, charging key, charging function ID, charging function address, application service provider ID, charging method (online or offline scheme), measurement scheme (total data volume, duration, combined total volume / duration, etc.), monitoring key, total volume threshold, time threshold, and monitoring time].

[0136] For reference: The UPF that serves as an uplink classifier or a bifurcation point may also serve as a PDU session anchor for the local part of the DN. In addition, instead of the UPF that serves as an uplink classifier or a bifurcation point, a separate V-UPF may be configured and may serve as a PDU session anchor for the local part of the DN. In this case, for the UPF that serves as a PDU session anchor for the local part of the DN, the V-SMF may be configured with the roaming offloading policy related to the session of the local part of the DN configured for the UPF that serves as an uplink classifier or a bifurcation point.

[0137] Figure 5 The structure of a UE according to an embodiment of the present disclosure is shown.

[0138] AsFigure 5 As shown in Figure 5 , the UE of the present disclosure may include a transceiver 510, a memory 520, and a UE controller (or a processor 530). According to the above communication method of the UE, the UE controller 530, the transceiver 510, and the memory 520 may operate. However, the constituent elements of the UE are not limited to the above examples. For example, the UE may include more or fewer constituent elements than those described above. In addition, the UE controller 530, the transceiver 510, and the memory 520 may be implemented as a single chip.

[0139] The transceiver 510 is a general term for the receiver of the UE and the transmitter of the UE, and may be capable of performing signal transmission or reception with a base station or a network entity. Signals transmitted or received by the base station may include control information and data. To this end, the transceiver 510 may include a radio frequency (RF) transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that low-noise amplifies the received signal and down-converts the frequency of the signal, and the like. This is only an example of the transceiver 510, and the constituent elements of the transceiver 510 are not limited to the RF transmitter and the RF receiver.

[0140] In addition, the transceiver 510 may include a wired or wireless transceiver, and may include various configurations for signal transmission or reception. In addition, the transceiver 510 may receive a signal via a wireless channel and output it to the UE controller 530, and may transmit the signal output from the UE controller 530 via a wireless channel. In addition, the transceiver 510 may receive a communication signal and output it to the UE controller 530, and may transmit the signal output from the UE controller 530 to a base station or a network entity via a wired or wireless network.

[0141] The memory 520 may store programs and data required for the operation of the UE. In addition, the memory 520 may store control information or data included in the signals obtained by the UE. The memory 520 may be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media.

[0142] The UE controller 530 may control a series of processes such that the UE operates according to the above embodiments of the present disclosure. The UE controller 530 may include at least one processor. For example, the UE controller 530 may include a communication processor (CP) that executes control for communication, and an application processor (AP) that controls upper layers such as application programs.

[0143] Figure 6 The structure of a base station according to an embodiment of the present disclosure is shown. Figure 6 The base station shown in Figure 6 may correspond to the radio access node (RAN) already referred to Figures 1 to 4 in the description.

[0144] As Figure 6 shown, the base station of the present disclosure may include a transceiver 610, a memory 620, and a base station controller 630 (or a processor). According to the above communication method of the base station, the base station controller 630, the transceiver 610, and the memory 620 may operate. However, the constituent elements of the base station are not limited to the above examples. For example, the base station may include more or fewer constituent elements than the above. According to an embodiment, Figure 6 all functions of the base station of Figure 6 may be implemented by being distributed between the CU and the DU. In this case, the CU and the DU may respectively execute some functions performed by the Figure 6 base station of

[0145] The transceiver 610 is a general term for the receiver of the base station and the transmitter of the base station, and may be capable of performing signal transmission or reception with the UE and / or network entities. The signals transmitted or received may include control information and data. For this purpose, the transceiver 610 may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that performs low-noise amplification on the received signal and down-converts the frequency of the signal, etc. This is only an example of the transceiver 610, and the constituent elements of the transceiver 610 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 610 may include a wired or wireless transceiver, and may include various configurations for signal transmission or reception.

[0146] In addition, the transceiver 610 may receive a signal via a communication channel (e.g., a wireless channel) and output it to the base station controller 630, and may transmit the signal output from the base station controller 630 via the communication channel. In addition, the transceiver 610 may receive a communication signal and output it to the processor, and may transmit the signal output from the processor to the UE or network entity via a wired or wireless network.

[0147] The memory 620 may store programs and data required for the operation of the base station. In addition, the memory 620 may store control information or data included in the signals obtained by the base station. The memory 620 may be configured as a storage medium such as ROM, RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media.

[0148] The base station controller 630 may control a series of processes such that the base station operates according to the above embodiments of the present disclosure. The controller 630 may include at least one processor. The methods described in the claims or the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0149] Figure 7 shows the structure of a network function (or network entity) according to an embodiment of the present disclosure. Figure 7 The network function (or network entity) shown in Figures 1 to 4 may correspond to various functions or entities of the core network described with reference to

[0150] As Figure 7 shown, the network function (NF) (or network entity) of the present disclosure may include a transceiver 710, a memory 720, and an NF controller 730 (or a processor). According to the above communication method of the network function (or network entity), the NF controller 730, the transceiver 710, and the memory 720 of the network function (or network entity) may operate. However, the constituent elements of the network function (or network entity) are not limited to the above examples. For example, the network function (or network entity) may include more or fewer constituent elements than those described above.

[0151] The transceiver 710 may be a general term for the receiver of the network function (or network entity) and the transmitter of the base station, and may perform signal transmission or reception with a UE, a base station, and / or another network function (or another network entity). In this case, the signals transmitted or received may include control information and data. To this end, the transceiver 710 may communicate with nodes in the core network via a wired or wireless transceiver. This is only an example of the transceiver 710, and the constituent elements of the transceiver 710 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, an RF receiver for low-noise amplifying the received signal and down-converting the frequency, etc., and may include various configurations for performing signal transmission or reception.

[0152] In addition, the transceiver 710 may receive a signal via a communication channel (e.g., a wireless channel or a channel of the core network) and output it to the NF controller 730, and may transmit the signal output from the NF controller 730 via the communication channel. In addition, the transceiver 710 may receive a communication signal and output it to the NF controller 730, and may transmit the signal output from the NF controller 730 to a UE, a base station, or a network entity via a wired or wireless network.

[0153] The memory 720 may store programs and data required for the operation of the network function (or network entity). In addition, the memory 720 may store control information or data included in the signals obtained by the network function (or network entity). The memory 720 may be implemented as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media.

[0154] The NF controller 730 may control a series of processes in which network functions (or network entities) operate according to the above embodiments of the present disclosure. The NF controller 730 may include at least one processor. The methods described in the claims or the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0155] The methods according to the various embodiments described in the claims or the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0156] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within the electronic device. At least one program may include instructions for causing the electronic device to execute the methods according to the various embodiments of the present disclosure defined by the appended claims and / or disclosed herein.

[0157] The program (software module or software) may be stored in a non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disc-ROM (CD-ROM), digital versatile disc (DVD), or other types of optical storage devices, or magnetic tape cartridges. Alternatively, any combination of some or all of them may form the memory in which the program is stored. In addition, multiple such memories may be included in the electronic device.

[0158] In addition, the program may be stored in an attachable storage device, which may access the electronic device through a communication network such as the Internet, intranet, local area network (LAN), wide area LAN (WLAN), and storage area network (SAN), or a combination thereof. Such a storage device may access the electronic device via an external port. In addition, a separate storage device on the communication network may access the portable electronic device.

[0159] In the above detailed embodiments of the present disclosure, according to the presented detailed embodiments, the elements included in the present disclosure are expressed in singular or plural. However, for ease of description, the singular form or the plural form is appropriately selected according to the presented situation, and the present disclosure is not limited by the elements expressed in singular or plural. Therefore, the elements expressed in plural may also include a single element, or the elements expressed in singular may also include multiple elements.

[0160] Although specific embodiments have been described in the detailed description of the present disclosure, it is clear that various modifications and changes can be made to the present disclosure without departing from the scope thereof. It is clear that, for example, part or all of some embodiments can be combined with part or all of one or more other embodiments, and such combinations also fall within the embodiments provided in the present disclosure. Therefore, the scope of the present disclosure should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0161] Although specific embodiments have been described in the detailed description of the present disclosure, it is clear that various modifications and changes can be made to the present disclosure without departing from the scope thereof. Therefore, the scope of the present disclosure should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0162] Although the present disclosure has been described with various embodiments, various changes and modifications can be suggested to those skilled in the art. The present disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method performed by a first Session Management Function (SMF) entity of a Home Public Land Mobile Network (HPLMN) in a mobile communication system, the method comprising: Sending a first message to a Policy Control Function (PCF) entity of the HPLMN to request an offloading policy for a Visited Public Land Mobile Network (VPLMN), the first message including information indicating that a Protocol Data Unit (PDU) session of the VPLMN supports a Home Routing Session Branch (HR-SBO); And Receiving a second message as a response to the first message from the PCF entity of the HPLMN, the second message including the offloading policy of the VPLMN based on the information.

2. The method according to claim 1, further comprising: Receiving a third message from a second SMF entity of the VPLMN to request creation of a PDU session; And Sending a fourth message as a response to the third message to the second SMF entity of the VPLMN, the fourth message including the offloading policy of the VPLMN.

3. The method according to claim 2, further comprising: Sending a fifth message to a Unified Data Management (UDM) entity to request subscription information for a PDU session; And Receiving a sixth message as a response to the fifth message from the UDM entity, the sixth message including the subscription information.

4. The method according to claim 2, wherein, The offloading policy of the VPLMN is applied to a User Plane Function (UPF) entity of the VPLMN, and wherein the UPF entity is selected and configured as an Uplink Classifier (ULCL) or a Branch Point (BP) based on the offloading policy of the VPLMN.

5. A method performed by a Policy Control Function (PCF) entity in a mobile communication system, the method comprising: Receiving a first message from a first Session Management Function (SMF) entity of a Home Public Land Mobile Network (HPLMN) to request an offloading policy for a Visited Public Land Mobile Network (VPLMN), the first message including information indicating that a Protocol Data Unit (PDU) session of the VPLMN supports a Home Routing Session Branch (HR-SBO); And Sending a second message as a response to the first message to the first SMF entity of the HPLMN, the second message including the offloading policy of the VPLMN based on the information.

6. The method according to claim 5, wherein, The offloading policy of the VPLMN is sent from the first SMF entity of the HPLMN to a second SMF entity of the VPLMN, wherein the offloading policy of the VPLMN is based on subscription information in a Unified Data Management (UDM) entity.

7. The method according to claim 6, wherein, The offloading policy of the VPLMN is applied to a User Plane Function (UPF) entity of the VPLMN, and wherein the UPF entity is selected and configured as an Uplink Classifier (ULCL) or a Branch Point (BP) based on the offloading policy of the VPLMN.

8. A first Session Management Function (SMF) entity of a Home Public Land Mobile Network (HPLMN) in a mobile communication system, the first SMF entity comprising: A transceiver; And A controller, coupled to the transceiver and configured to: Send a first message to the Policy Control Function (PCF) entity of the HPLMN to request an offloading policy for the Visited Public Land Mobile Network (VPLMN). The first message includes information indicating that the PDU session of the VPLMN supports Home Routing Session Branch (HR-SBO), and Receive a second message from the PCF entity of the HPLMN as a response to the first message. The second message includes the offloading policy of the VPLMN based on the information.

9. The first SMF entity according to claim 8, wherein, The controller is further configured to: Receive a third message from the second SMF entity of the VPLMN to request the creation of a PDU session, and Send a fourth message to the second SMF entity of the VPLMN as a response to the third message. The fourth message includes the offloading policy of the VPLMN.

10. The first SMF entity according to claim 9, wherein, The controller is further configured to: Send a fifth message to the Unified Data Management (UDM) entity to request subscription information for the PDU session, and Receive a sixth message from the UDM entity as a response to the fifth message. The sixth message includes the subscription information.

11. The first SMF entity according to claim 9, wherein The offloading policy of the VPLMN is applied to the User Plane Function (UPF) entity of the VPLMN, and wherein, the UPF entity is selected and configured as an Uplink Classifier (ULCL) or a Branch Point (BP) based on the offloading policy of the VPLMN.

12. A Policy Control Function (PCF) entity in a mobile communication system, the PCF entity comprising: A transceiver; and A controller, coupled to the transceiver and configured to: Receive a first message from the first Session Management Function (SMF) entity of the Home Public Land Mobile Network (HPLMN) to request an offloading policy for the Visited Public Land Mobile Network (VPLMN). The first message includes information indicating that the PDU session of the VPLMN supports Home Routing Session Branch (HR-SBO), and Send a second message to the first SMF entity of the HPLMN as a response to the first message. The second message includes the offloading policy of the VPLMN based on the information.

13. The PCF entity according to claim 12, wherein, The offloading policy of the VPLMN is sent from the first SMF entity of the HPLMN to the second SMF entity of the VPLMN.

14. The PCF entity according to claim 13, wherein, The offloading policy of the VPLMN is based on the subscription information in the Unified Data Management (UDM) entity.

15. The PCF entity according to claim 13, wherein, The offloading policy of the VPLMN is applied to the User Plane Function (UPF) entity of the VPLMN, and wherein, the UPF entity is selected and configured as an Uplink Classifier (ULCL) or a Branch Point (BP) based on the offloading policy of the VPLMN.

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