Session management method and device based on dynamic backhaul network time delay in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. According to an aspect of the present disclosure, a method of a session management function (SMF) in a wireless communication system may include receiving a first message from an access and mobility management function (AMF), the first message including information indicating use of a dynamic satellite backhaul; a second message indicating the use of the dynamic satellite backhaul is sent to a policy control function (PCF) based on receiving the first message, wherein the PCF triggers a quality of service (QoS) monitoring operation for the dynamic satellite backhaul based on the second message.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for session management based on dynamic backhaul network delay in a wireless communication system. Background Art

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

[0003] At the beginning 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 and low-latency communications (URLLC) and massive machine type communications (mMTC), standardization of the following technologies is already underway: beamforming and massive MIMO for mitigating radio wave path loss in millimeter waves and increasing radio wave transmission distance; support parameter sets (e.g., operating multiple subcarrier spacings) for efficient use of millimeter wave resources and dynamic operation of time slot formats; initial access technology for supporting multi-beam transmission and broadband; definition and operation of bandwidth parts (BWPs); new channel coding methods (such as low-density parity-check (LDPC) codes for large amounts of data transmission and polarization codes for highly reliable transmission of control information); L2 preprocessing; and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services supported by 5G mobile communication technology, discussions on the improvement and performance enhancement of initial 5G mobile communication technology are ongoing, and there is already physical layer standardization on technologies such as: Vehicle-to-Everything (V2X) for assisting driving decisions of autonomous vehicles based on information about the location and status of the vehicle transmitted by the vehicle and for improving user convenience; NR-U (New Radio Unlicensed) for system operation that is designed to comply with various regulatory requirements in unlicensed bands; NR UE energy saving; Non-Terrestrial Network (NTN), which is UE-satellite direct communication for providing coverage in areas where terrestrial network communications are not available; and positioning.

[0005] In addition, standardization is being continued in air interface architecture / protocols for technologies such as: Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries; Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner; Mobility enhancements including conditional handover and dual active protocol stack (DAPS) handover; and two-step random access (2-step RACH for NR) for simplifying the random access process. System architecture / services for the following technologies are also being standardized: 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 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 growing exponentially, will be connected to the communication network, and it is therefore expected that there will be a need to enhance the functions and performance of 5G mobile communication systems and the integrated operation of connected devices. To this end, new research related to the following technologies is planned: Extended Reality (XR) for effectively supporting Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR), 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.

[0007] In addition, such developments in 5G mobile communication systems will serve not only as a basis for developing: new waveforms for providing coverage in the terahertz band of 6G mobile communication technology; multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and large antennas; metamaterial-based lenses and antennas for improving the coverage of terahertz band signals; high-dimensional spatial multiplexing technology using OAM (orbital angular momentum); and RIS (reconfigurable smart surface), but will also serve as a basis for developing: full-duplex technology for increasing the frequency efficiency of 6G mobile communication technology and improving system networks; AI-based communication technology 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 technology for implementing services at a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources. Summary of the invention

[0008] [Technical solution]

[0009] Various embodiments of the present disclosure provide a method and device for session management based on dynamic backhaul network delay in a wireless communication system.

[0010] The objects of the present disclosure are not limited to the above contents, and other unmentioned objects will be apparent to those of ordinary skill in the art from the following description.

[0011] According to an embodiment, a method of a session management function (SMF) in a wireless communication system may include: receiving a first message from an access and mobility management function (AMF), the first message including information indicating the use of a dynamic satellite backhaul; sending a second message indicating the use of a dynamic satellite backhaul to a policy control function (PCF) based on the receipt of the first message, the PCF triggering quality of service (QoS) monitoring for the dynamic satellite backhaul based on the second message.

[0012] As an embodiment, the method may further include: in response to the second message, receiving a third message including policy control and charging (PCC) rule information related to the SMF and policy control request trigger condition information from the PCF entity.

[0013] As an embodiment, the PCC rule information may include quality of service (QoS) monitoring information for dynamic satellite backhaul delay control. The QoS monitoring information may include at least one of information indicating at least one QoS parameter to be measured, information indicating a reporting frequency, information indicating a threshold associated with at least one QoS parameter to be measured, information indicating a reporting target, and information indicating whether to directly notify an event.

[0014] As an embodiment, the PCC rule information may further include at least one of a QoS parameter set and an alternative QoS parameter set for dynamic satellite backhaul delay.

[0015] As an embodiment, the policy control request trigger condition information related to the SMF may include at least one of a first policy control request trigger condition for the SMF to identify a situation in which QoS parameters can be met through a satellite backhaul network and a second policy control request trigger condition for QoS monitoring for dynamic satellite backhaul delay control, in which the network delay can be dynamically changed in a user plane function (UPF).

[0016] As an embodiment, the method may further include selecting the UPF based on a delay of a backhaul network associated with the user plane.

[0017] As an embodiment, the method may further include sending a session management policy modification request message including a measurement value of a delay of a backhaul network associated with a user plane to the PCF, and receiving a session management policy modification response message including PCC rule information and policy control request triggering condition information from the PCF.

[0018] As an embodiment, the method may further include sending to the AMF at least one of QoS monitoring indicator information, QoS monitoring report frequency information, and QoS monitoring threshold information generated based on the QoS monitoring information.

[0019] As an embodiment, the method may further include sending QoS monitoring policy information generated based on the QoS monitoring information to the UPF. The UPF may use the QoS monitoring policy information to measure the network delay of the N3 part.

[0020] As an embodiment, the first message may include satellite backhaul category information and a dynamic satellite backhaul delay control request indicator.

[0021] According to an embodiment, a session management function (SMF) device in a wireless communication system may include a transceiver; and a controller coupled to the transceiver. The controller may be configured to receive a first message including information indicating the use of a dynamic satellite backhaul from an access and mobility management function (AMF), send a second message indicating the use of a dynamic satellite backhaul to a policy control function (PCF) based on the reception of the first message, and the PCF triggers quality of service (QoS) monitoring for the dynamic satellite backhaul based on the second message. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] With reference to the following detailed description, the present disclosure and its accompanying many aspects will be better understood and more comprehensive will be obtained by referring to the accompanying drawings, in which:

[0023] Figure 1 The structure of a 5G system according to an embodiment of the present disclosure is shown;

[0024] Figure 2 A 5G system structure is shown in which one or more backhaul network connections between a RAN and a 5G core network are possible according to an embodiment of the present disclosure;

[0025] Figure 3 A method for managing policy control and charging rules based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown;

[0026] Figure 4 A method for managing policy control and charging rules based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown;

[0027] Figure 5A and Figure 5B A session management method based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown;

[0028] Figure 6 The structure of a UE according to an embodiment of the present disclosure is shown;

[0029] Figure 7 The structure of a base station according to an embodiment of the present disclosure is shown; and

[0030] Figure 8 The structure of a network function entity according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0031] Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising," and their derivatives, mean to include without limitation; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with," and their derivatives may mean to include, be included within, be interconnected with, contain, be contained within, be connected to or connected with, be connected to or connected with, be communicative with, cooperate with, interleave, juxtapose, be adjacent to, be bound to or bound with, have, have the property of, and the like; 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 a combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0032] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and is contained in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data, or parts thereof suitable for implementation in appropriate computer-readable program codes. 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 disc (CD), a digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical or other communication links that transmit temporary electrical or other signals. A non-transitory computer-readable medium includes a medium that can permanently store data, and a medium that can store data and then rewrite data, such as a rewritable optical disc or an erasable storage device.

[0033] 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.

[0034] Discussed below Figures 1 to 8 The various embodiments used to describe the principles of the present disclosure in this patent document are merely exemplary and should not be interpreted 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.

[0035] Hereinafter, the working principle of the present disclosure will be described with reference to the accompanying drawings.

[0036] When describing the embodiments, descriptions of technologies known in the art and not directly related to the present disclosure are omitted. This is to further clarify the main points of the present disclosure without making it unclear.

[0037] For the same reason, some elements may be exaggerated or schematically shown. The size of each element does not necessarily reflect the actual size of the element. In all the drawings, the same reference numerals are used to represent the same elements.

[0038] The advantages and features of the present disclosure and the methods for realizing the advantages and features of the present disclosure can be understood by the embodiments described below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed herein, and various changes may be made thereto. The embodiments disclosed herein are only used to inform the ordinary technicians in the field of the categories of the present disclosure. The present disclosure is limited only by the attached claims. Throughout the specification, the same reference numerals represent the same elements.

[0039] It should be understood that the blocks in each flowchart and the combination of flowcharts can be executed by computer program instructions. Since computer program instructions can be provided in a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, the instructions executed by the processor of the computer or other programmable data processing device generate a device for performing the functions described in conjunction with the blocks of each flowchart. Since computer program instructions can be stored in a computer-usable or computer-readable memory, and the functions are implemented in a specified manner for a computer or other programmable data processing device, the instructions stored in the computer-usable or computer-readable memory can produce a product including an instruction device, and the instruction device is used to perform the functions described in conjunction with the blocks in each flowchart. Since computer program instructions can be provided in a computer or other programmable data processing device, the instructions for generating a process performed by a computer as a series of operating steps are executed on the computer or other programmable data processing device, and the computer or other programmable data processing device can be operated to provide steps for performing the functions described in conjunction with the blocks in each flowchart.

[0040] In addition, each block can represent a module, segment or a part of code including one or more executable instructions for performing a specified logical function. In addition, it should also be noted that in some alternative embodiments, the functions mentioned in the block can occur in different orders. For example, two blocks shown in succession can be performed substantially simultaneously, or in reverse order according to the corresponding function.

[0041] As used herein, the term "unit" means a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). The unit plays a certain role. However, the "unit" is not limited to software or hardware. The "unit" can be configured in a storage medium, which can be addressed or can be configured to execute one or more processors. Therefore, as an example, the "unit" includes elements such as software elements, object-oriented software elements, class elements and task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data architectures, tables, arrays and variables. The functions provided in the components and "units" can be combined into a smaller number of components and "units", or further separated into additional components and "units". In addition, the components and "units" can be implemented as one or more CPUs in an execution device or a secure multimedia card. According to an embodiment, the "....unit" may include one or more processors.

[0042] The terms used in this article to identify access nodes, terms representing network entities, terms representing messages, terms representing network entity interfaces, and terms representing various identification information are provided as examples for convenience of description. Therefore, the present disclosure is not limited by these terms, and other terms representing objects with equivalent technical concepts can be used to replace these terms.

[0043] For ease of description, terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) and / or 3GPP 5G standards may be used herein. However, the present disclosure is not limited to these terms and names, and is also applicable to systems conforming to other standards.

[0044] The advancement of satellite communication technology has brought about efforts to integrate limited-use satellite communication technology into mobile communication networks. In particular, research is being conducted to introduce satellite links in the backhaul section (the section between the radio access network (RAN) and the core network) connected by traditional fiber-based wired links.

[0045] The Third Generation Partnership Project (3GPP) is standardizing various scenarios for integrating mobile communications and 5G technologies in fifth-generation (5G) communication systems. In particular, a method for introducing satellite connectivity in the backhaul portion that connects the radio access network (RAN) and the core network is standardized. Satellite connectivity has various advantages, such as reducing the cost of building wired links (e.g., installing embedded fiber optic cables). At the same time, when satellite technology is applied to the backhaul portion, phenomena such as variable network conditions or high latency may occur, and additional mechanisms for satisfying quality of service (QoS) in the 5G system may be required.

[0046] When satellite technology is applied to the backhaul portion, higher latency may occur in sending control signals and user data through the RAN or core network installed on the ground compared to using a terrestrial backhaul network. Due to such high latency, it may be necessary to change the session management method, including the selection of network functions (NFs) for session management and the selection of QoS profiles for policy and charging management.

[0047] Therefore, when high latency may occur in the backhaul portion due to the characteristics of using a non-terrestrial backhaul network including a satellite or other backhaul network, and further when the latency in the backhaul portion changes dynamically, there may be a need for technology to determine policy control and charging rules that meet the QoS requirements of the service.

[0048] Various embodiments of the present disclosure may provide a method and apparatus for dynamic backhaul network delay-based session management in a wireless communication system.

[0049] The objects of the present disclosure are not limited to the above contents, and other unmentioned objects will be apparent to those of ordinary skill in the art from the following description.

[0050] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components in the accompanying drawings are represented by the same reference numerals as much as possible. In addition, it should be noted that the accompanying drawings of the present disclosure are provided to help understand the present disclosure, and the present disclosure is not limited to the form or arrangement shown in the accompanying drawings of the present disclosure.

[0051] Figure 1 The structure of a 5G system related to an embodiment of the present disclosure is shown.

[0052] Reference Figure 1 , the 5G system architecture may include various components (e.g., network functions (NFs)). Figure 1Some components are shown, including an authentication server function (AUSF) device 110, a (core) access and mobility management function (AMF) device 103, a session management function (SMF) device 104, a policy control function (PCF) device 107, an application function (AF) device 108, a unified data management (UDM) device 106, a data network (DN) 112, a user plane function (UPF) device 105, a (radio) access network (R) AN 102, and a terminal, i.e., a user equipment (UE) 101. Figure 1 Also shown are a Network Slice Selection Function (NSSF) device 109 and a Network Slice Specific Authentication and Authorization Function (NSSAAF) device 111 for each network slice.

[0053] Figure 1 Each device shown may be implemented as a server or device, or may be implemented as a network slice instance. When implemented as a network slice instance, two or more identical or different network slice instances may be implemented in one server or device, or one network slice instance may be implemented in two or more servers or devices.

[0054] Each NF can support the following functions.

[0055] AUSF 110 may process and store data used to authenticate the UE.

[0056] AMF 103 can provide functions for access and mobility management of each UE, and each UE can be basically connected to one AMF. Specifically, AMF 103 can support functions such as: inter-core network (CN) node signaling for mobility between 3GPP access networks, radio access network (RAN) CP interface (i.e., N2 interface) termination, NAS signaling termination (N1), NAS signaling security (NAS encryption) and integrity protection, AS security control, registration management (registration area management), connectivity management, idle mode UE reachability (including control and execution of paging retransmission), mobility management control (subscription and policy), intra-system mobility and inter-system mobility support, network slicing support, SMF selection, lawful interception (interface for AMF events and LI systems), transmission of session management (SM) messages between UE and SMF, transparent proxy for SM message routing, access authentication, access authorization including roaming authorization check, transmission of SMS messages between UE and short message service function (SMSF), security anchor function (SEA), and security context management (SCM). All or some of the functions of AMF 103 may be supported in a single AMF instance operating as one AMF.

[0057] DN 112 may mean, for example, operator service, Internet access, or third-party service. DN 112 may send a downlink protocol data unit (PDU) to UPF 105 or receive a PDU sent from UE 101 from UPF 105.

[0058] PCF 107 can receive information about packet flows from application servers and provide functions for determining policies such as mobility management or session management. Specifically, PCF 107 can support functions such as supporting a unified policy framework for controlling network operations, providing policy rules to allow CP functions (e.g., AMF or SMF) to execute policy rules, and implementing a front end for accessing subscription information related to policy decisions in a user data repository (UDR).

[0059] SMF 104 provides session management functions, and if the UE has multiple sessions, each session can be managed by a different SMF. Specifically, SMF 104 can support functions such as: session management (e.g., session establishment, modification, and release, including maintenance of tunnels between UPF and AN nodes), UE IP address allocation and management (optionally including authentication), selection and control of UP functions, flow control settings for routing traffic to the appropriate destination in UPF, interface termination towards policy control functions, execution of the control part of policy and QoS, legal interception (for interfaces to SM events and LI systems), termination of the SM part of NAS messages, downlink data notification, AN-specific SM information publisher (transmitted to AN via AMF and N2), SSC mode determination of sessions, and roaming functions. As described above, some or all of the functions of SMF 104 can be supported within a single SMF instance operating as one SMF.

[0060] The UDM 106 may store, for example, subscription data and policy data of the user. The UDM 106 may include two parts, namely, an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

[0061] FE may include UDM FE responsible for location management, subscription management, and certificate processing, and PCF-FE responsible for policy control. UDR may store data required for the functions provided by UDM-FE and policy profiles required by PCF. The data stored in UDR may include policy data and user subscription data, and the user subscription data includes subscription identifiers, security certificates, access and mobility-related subscription data, and session-related subscription data. UDM-FE may access subscription information stored in UDR and support functions such as authentication certificate processing, user identity processing, access authentication, registration / mobility management, subscription management, and SMS management.

[0062] The UPF 105 may deliver downlink PDUs received from the DN 112 to the UE 101 via the (R)AN 102, and may deliver PDUs received from the UE 101 to the DN 112 via the (R)AN 102. Specifically, the UPF 105 may support functions such as: an anchor point for intra-RAT / inter-RAT mobility, an external PDU session point for interconnection to a data network, packet routing and forwarding, user plane part of policy rules and packet inspection, lawful interception, service usage reporting, an uplink classifier for supporting routing of service flows to the data network, a branch point for supporting multi-homed PDU sessions, QoS processing for the user plane (e.g., filtering, gating, uplink / downlink rate enforcement), uplink service verification (SDF mapping between service data flows (SDF) and QoS flows), transport level packet marking in uplink and downlink, downlink packet buffering, and downlink data notification triggering. All or some of the functionality of UPF 105 may be supported in a single UPF instance operating as one UPF.

[0063] AF 108 may interact with the 3GPP core network to provide services (eg, support functions such as application influencing on traffic routing, network capability exposure access, and interaction with a policy framework for policy control).

[0064] (R)AN 102 refers to a general term for new radio access technologies that support E-UTRA (Evolved E-UTRA evolved from 4G radio access technology) and new radio access technologies (NR: New Radio) such as gNB.

[0065] The gNB may support functions such as: functions for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic resource allocation (i.e., scheduling) to the UE 101 on uplink / downlink), Internet Protocol (IP) header compression, encryption and integrity protection of user data flows, where routing to the AMF 103 is not determined based on information provided to the UE 101, selection of the AMF 103 when the UE 101 attaches, routing of user plane data to the UPF 105, routing of control plane information to the AMF 103, connection establishment and release, scheduling and transmission of paging messages (generated from the AMF 103), scheduling and transmission of system broadcast information (generated from the AMF 103) 103 or Operation and Maintenance (O&M) generation), measurements and measurement report configuration for mobility and scheduling, transport level packet marking on the uplink, session management, network slicing support, QoS flow management and mapping to data radio bearers, support for UEs in inactive mode, distribution of NAS messages, NAS node selection, radio access network sharing, dual connectivity, and tight interworking between NR and E-UTRA.

[0066] UE 101 may mean user equipment. User equipment may be referred to as a terminal, mobile equipment (ME) or mobile station (MS). In addition, the user equipment may be a portable device such as a laptop computer, a mobile phone, a personal digital assistant (PDA), a smart phone or a multimedia device, or may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device. In the following description, the user equipment is referred to as a user equipment (UE) or a terminal.

[0067] exist Figure 1 In the description, the network exposure function (NEF) device and the NF repository function (NRF) device are not shown for clarity of description, but if necessary, the following description Figure 2 All NFs shown in 5 can interact with NEF and NRF.

[0068] Describes NRF. NRF( Figure 1 The first NF instance may support a service discovery function (not shown). When a second NF discovery request is received from a first NF instance, information about the second NF instance discovered after performing the second NF discovery operation may be provided to the first NF instance. In addition, available NF instances and the services they support may be maintained.

[0069] At the same time, despite Figure 1 An exemplary reference model is shown for convenience of description (in which a UE uses one PDU session to access one DN), but the present disclosure is not limited thereto.

[0070] UE 101 can use multiple PDU sessions to access two data networks (i.e., local and central) at the same time. In this case, two SMFs can be selected for different PDU sessions. However, each SMF can have the ability to control both local and central UPFs in a PDU session.

[0071] Furthermore, UE 101 may simultaneously access two (ie, local and central) data networks provided in a single PDU session.

[0072] In the 3GPP system, the conceptual link connecting NFs in the 5G system is defined as a reference point. Figure 1 Example reference points in the illustrated 5G system architecture are provided below:

[0073] N1: reference point between UE and AMF;

[0074] N2: reference point between (R)AN and AMF;

[0075] N3: reference point between (R)AN and UPF;

[0076] N4: reference point between SMF and UPF;

[0077] N5: reference point between PCF and AF;

[0078] N6: Reference point between UPF and data network;

[0079] N7: reference point between SMF and PCF;

[0080] N8: reference point between UDM and AMF;

[0081] N9: reference point between two core UPFs;

[0082] N10: Reference point between UDM and SMF;

[0083] N11: Reference point between AMF and SMF;

[0084] N12: reference point between AMF and AUSF;

[0085] N13: Reference point between UDM and Authentication Server Function (AUSF);

[0086] N14: reference point between two AMFs; and

[0087] N15: Reference point between PCF and AMF in non-roaming case, and between PCF and AMF in the visited network in roaming case.

[0088] In the following description, the terminal may refer to UE 101, and the terms "UE" and "terminal" may be used interchangeably. In this case, unless otherwise defined, the terminal may be understood as UE 101.

[0089] The UE accesses a data network (e.g., a network providing Internet services) through a 5G system and establishes a session, and an identifier called a data network name (DNN) can be used to identify each data network. When the UE establishes a session with a network system, the DNN can be used to determine, for example, NFs related to the user plane, inter-NF interfaces, and user policies. The DNN can be used, for example, to select the SMF and UPF for a PDU session, and can be used to select an interface between the UPF and the data network for the PDU session (e.g., an N6 interface). The DNN can be used to determine the policy of the mobile communication carrier to be applied to the PDU session.

[0090] Figure 2 A 5G system structure is shown in which one or more backhaul network connections between a RAN and a 5G core network are possible according to an embodiment of the present disclosure.

[0091] At least one control plane backhaul network and / or at least one user plane backhaul network may be connected between a RAN and a core network. The control plane backhaul network may connect the RAN and the AMF and may use an N2 interface (e.g., Figure 2 (A), (B), and (C) of FIG. 1 ). The user plane backhaul network may connect the RAN and the UPF and may use the N3 interface (e.g., Figure 2 (D) and (E)). The type of backhaul network may include a terrestrial backhaul network (e.g., Figure 2 (C) and (E)) and non-terrestrial backhaul networks (using satellites, drones, etc.) (e.g. Figure 2 (A), (B), and (D)). A satellite backhaul network may connect one or more satellites (e.g., Figure 2 (B) and (D)).

[0092] For example, Figure 2 As shown in (A), the first satellite backhaul network Satellite Backhaul#1 can be connected between the RAN and the AMF as a control plane backhaul network, and the first satellite backhaul network can be connected to a satellite Satellite#1. Figure 2 As shown in (B) and (D) of FIG. 1 , the second satellite backhaul network Satellite Backhaul#2 can be connected between the RAN and the AMF and between the RAN and the first UPF UPF#1, serving as a control plane backhaul network and a user plane backhaul network, respectively, and the second satellite backhaul network can be connected to two satellites Satellite#2 and Satellite#3. Figure 2 As shown in (C) and (E), the terrestrial backhaul network can be connected between the RAN and AMF and between the RAN and the second UPF UPF#2, serving as the control plane backhaul network and the user plane backhaul network respectively.

[0093] When the PCF determines the SM policy, the network delay that occurs in the backhaul network can be taken into account. For example, when configuring QoS parameters suitable for the service provided to the UE, the PCF can include a packet delay budget (PDB) value. The PDB corresponds to an upper limit on the packet delay that can be allowed between the UE and the N6 interface terminating the UPF. Therefore, when a satellite network is used in the section between the RAN and the UPF, it may be necessary to determine an SM policy that includes a longer PDB value than when using a terrestrial network.

[0094] The network delay occurring in the backhaul network may change dynamically, and this dynamic backhaul network delay may be taken into account when the PCF determines the SM strategy. For example, when the backhaul network connecting the RAN and the UPF is a network connected to one or more satellites ( Figure 2D), and when the satellite provides mobile satellite access, the backhaul network delay may vary according to the location of the UE and / or the location of the mobile satellite. In particular, in the case of a mobile satellite constellation network, the satellites constellating the satellite constellation move along a predetermined path at a predetermined period, and the path in the mobile satellite constellation along which the packet is routed according to the location of the UE is variable. As an example, the UE may send and receive packets to and from the UPF through only one satellite at a specific time, and may send and receive packets to and from the UPF through two satellites at another time, and each backhaul network delay may vary according to the number of satellites passed.

[0095] In a communication system where the backhaul network delay can change dynamically, the PCF can adaptively determine the SM policy to adapt to the backhaul network delay value, and to this end, the SMF can request the RAN and / or UPF to measure and report the uplink and / or downlink packet delay between the RAN and the UPF. The SMF can report the measurement values ​​received from the RAN and / or UPF to the PCF to determine whether the PCF can determine a new SM policy (which may include a new PDB value). In this case, the PCF can communicate with the AF to determine whether the reported backhaul network delay meets the user service requirements. When the PCF determines a new SM policy, the PCF can provide the new SM policy to the SMF.

[0096] Figure 3 A method of managing policy control and charging rules based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown.

[0097] The PCF may monitor the delay value of the satellite backhaul network and adaptively determine the PCC rule. To this end, the PCF may provide the SMF with PCC rule information describing the rule for monitoring the delay value of the satellite backhaul network. The SMF may provide the PCC rule information to each of the RAN and / or UPF. The RAN and UPF may measure the network delay of the satellite backhaul network portion based on the information indicated by the QoS SMF.

[0098] Reference Figure 3 ,The PCF can provide QoS monitoring for dynamic satellite backhaul control to the SMF to instruct the SMF how to monitor the satellite backhaul network latency.

[0099] The QoS monitoring information may include at least one of the following parameters:

[0100] QoS parameters to be measured: The QoS parameters to be measured can be indicated. This can include UL packet delay, DL packet delay, or round-trip packet delay;

[0101] Reporting frequency: The reporting frequency can be indicated. The definition of an event can be used when a specific event occurs, and if it is periodic, a periodic value can be used. The following can be used as the definition of an event: When the QoS parameter to be measured is equal to or greater than the following threshold, or When the QoS parameter to be measured is equal to or less than the following threshold;

[0102] Threshold: may indicate a predetermined value of a QoS parameter to be measured; and

[0103] Report target: The target NF of the report can be indicated. For example, it can include PCF, AF, NEF or other NFs defined by PCF.

[0104] Indication of direct event notification: The UPF can instruct reporting directly to the reporting target without relying on the SMF.

[0105] After receiving the QoS monitoring for dynamic satellite backhaul control information from the PCF, the SMF may provide the QoS monitoring indication, QoS monitoring reporting frequency and / or QoS monitoring threshold to the RAN during the PDU session establishment / modification process.

[0106] QoS Monitoring Indication: The RAN may be instructed to measure QoS parameter values ​​between the RAN and the UPF. The SMF may instruct to measure packet delays of QoS parameters corresponding to some or all of the QoS parameters to be measured provided by the PCF.

[0107] QoS Monitoring Reporting Frequency: It can indicate the frequency with which the RAN can measure and report QoS parameters to the SMF. The SMF can determine the reporting frequency by determining a value that can satisfy the reporting frequency condition provided by the PCF. For example, even when the reporting frequency provided by the PCF is a specific event, the SMF can determine a time value sufficient for the SMF to recognize the event and indicate it to the RAN. As another example, when the reporting frequency provided by the PCF is a constant frequency, the SMF can determine a value equal to or different from the frequency time value provided by the PCF, and indicate the value to the RAN.

[0108] QoS Monitoring Threshold: A constant value that may indicate a QoS parameter value to be measured by the RAN. The SMF may determine the QoS monitoring threshold by determining a value that may satisfy the reporting frequency and / or threshold conditions provided by the PCF. For example, the SMF may determine a value that is equal to or different from the threshold provided by the PCF and indicate the value to the RAN.

[0109] When the SMF receives QoS monitoring for dynamic satellite backhaul control information from the PCF, the SMF may provide the QoS monitoring policy to the UPF during the PDU session establishment / modification process. The QoS monitoring policy may include QoS parameters to be measured, reporting frequencies, thresholds, reporting targets, and / or indications of direct event notifications. Each value may be determined by the SMF based on the value provided by the PCF. For example, upon receiving an indication of NWDAF and direct event notification as a reporting target value from the PCF, the SMF may provide the same indication to the UPF to allow the UPF to report the measurement value directly to the NWDAF. Such an example may be implemented if the PCF intends to analyze the dynamically changing pattern of the satellite backhaul network through the NWDAF and refer to it to determine the PCC rules based on the request of the AF or the PCF's own judgment.

[0110] Figure 4 A method of managing policy control and charging rules based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown.

[0111] Policy control and charging rules (PCC rules) may include a policy control request trigger (PCRT) associated with the SMF. The PCF may provide the SMF with the SMF-related PCRT during the SM policy association establishment / modification process. (For example, the PCF may send the PCRT to the SMF via the Npcf_SMPolicyControl_Create response message and the Npcf_SMPolicyControl_Update response message).

[0112] When the SMF receives the SMF-related PCRT from the PCF, the SMF can request to update the SM policy association by communicating with the PCF according to the description of the PCRT when an event that satisfies the reporting condition described by the PCRT occurs. (For this purpose, for example, the SMF can send a Npcf_SMPolicyControl_Update request message to the PCF).

[0113] When an event that satisfies the reporting condition described by the PCRT occurs from the SMF and the information requested in the description of the PCRT is received, the PCF can determine whether the SM policy previously provided to the SMF needs to be updated. In this case, the PCF can communicate with the AF to send and receive information necessary to determine the SM policy. The PCF can determine that the SM policy needs to be updated and provide the updated SM policy to the SMF. (To this end, for example, the PCF can send an Npcf_SmPolicyControl_Update response message to the SMF. At the same time, the update can include correction and / or deletion.

[0114] When the PCF receives a request from the AF to indicate the occurrence of a specific event and related information (for this purpose, for example, the AF can send the definition of the event to the PCF via the Npcf_EventExposure_Subscibe message), the PCF can notify the AF (for this purpose, for example, the PCF can send the Npcf_EventExposure_Notify message to the AF). For the above-mentioned dynamic satellite backhaul control, the AF can request the PCF to transmit QoS monitoring for dynamic satellite backhaul control to the AF.

[0115] Reference Figure 4 , the PCF may instruct the SMF to provide an SMF-related PCRT for monitoring and reporting dynamically changing satellite backhaul network delays. QoS selected by the SMF for dynamic satellite backhaul: When the SMF identifies QoS parameters that can be satisfied by the satellite backhaul network (in the satellite backhaul network, the network delay in the UPF may change dynamically), the PCF may be instructed to report (1) a QoS flow identifier including the satisfied QoS parameters and / or (2) the measured QoS parameter values. For example, when receiving one or more QoS rules and one or more candidate QoS rules from the PCF in consideration of the dynamic satellite backhaul network delay during a PDU session establishment / modification process, and after requesting one or more candidate UPFs to which the SMF can be connected to measure the backhaul network delay, a UPF is selected based on the measured values, if there are one or more QoS rules that can be satisfied by the selected UPF, the SMF may identify that the QoS selected by the SMF for the dynamic satellite backhaul PCRT condition is satisfied, and report the QoS rules to the PCF. If one or more QoS rules are satisfied, the PCF may determine one and notify the SMF. Alternatively, if one or more QoS rules are satisfied, the SMF may determine one and notify the PCF. Alternatively, if the QoS rules are not met, the SMF may notify the PCF that the QoS rules are not met.

[0116] QoS monitoring for dynamic satellite backhaul control: If there are dynamic backhaul network delay values ​​measured by the UPF and / or RAN, the PCF may be instructed to report the relevant QoS parameter values. For example, when the PCF provides a PCC rule with QoS monitoring for dynamic satellite backhaul control PCC rule information (as described above with reference to Figure 3 As described above), the PCF may instruct to report the QoS parameter measurement results requested by the PCF.

[0117] In the present disclosure, the QoS selected for the SMF for dynamic satellite backhaul may be referred to as a policy control request trigger condition or a first policy control request trigger condition, which is used for the SMF to identify situations in which QoS parameters can be met by the satellite backhaul network (in which the network delay in the UPF can change dynamically), and QoS monitoring for dynamic satellite backhaul may be referred to as a policy control request trigger condition or a second policy control request trigger condition for QoS monitoring for dynamic satellite backhaul delay control.

[0118] Figure 5A and Figure 5B A session management method based on dynamic backhaul network delay according to an embodiment of the present disclosure is shown.

[0119] Step 1: The UE may send a PDU session establishment request message to the AMF via the RAN.

[0120] Step 2: The AMF may determine at least one of (1) to (5) related to the type of backhaul network present between the RAN and the core network.

[0121] (1) Whether there is one type of backhaul network between the current RAN and the core network, or whether there are multiple types of backhaul networks (including, for example, when there is only a terrestrial backhaul network between the current RAN and the core network, or when there is only a geostationary or geosynchronous earth orbit (GEO) (or medium earth orbit (MEO) or low earth orbit (LEO)) satellite backhaul network, or when there are GEO satellite backhaul, LEO satellite backhaul, and terrestrial backhaul networks).

[0122] (2) Whether only the same backhaul network can be used for the control plane and the user plane.

[0123] (3) Whether different types of backhaul networks can be used for the control plane and the user plane.

[0124] (4) The type of backhaul network used (or available) for the control plane.

[0125] (5) The type of backhaul network used (or available) in the user plane.

[0126] The AMF may determine the type of the backhaul network using at least one piece of information among (A) to (E).

[0127] (A) Global RAN Node ID received from the RAN.

[0128] (B) UE location information received from the RAN (which may include, for example, Tracking Area (TA) ID, Cell ID, PLMN ID and country).

[0129] (C) Information received from the RAN regarding the backhaul network type.

[0130] (D) Network operations and maintenance information (operations, administration, and management, or operations, administration, and maintenance (OA M or OAM)).

[0131] (E)AMF configuration information, etc.

[0132] The AMF may select an SMF for session management. The AMF may send a message (Nsmf_PDUSession_CreateSMContext request) to the SMF requesting the establishment of a PDU session. If the AMF determines that the type of backhaul network used in the control plane is a satellite backhaul network, the AMF may provide the SMF with a satellite backhaul category. The values ​​of the satellite backhaul category may include NR(GEO), NR(MEO), NR(LEO), NR(OTHERSAT), etc., depending on the type of satellite. For example, when the AMF determines that the RAN is using a satellite backhaul network based on the global RAN node ID received from the RAN through the N2 interface during the UE's registration process, the type of satellite backhaul network that the RAN is using may be written to the value of the satellite backhaul category value.

[0133] The AMF may determine whether the type of backhaul network used (or that may be used) in the control plane and / or the user plane is the type of backhaul network in which the network delay value may change dynamically. In this case, the backhaul network may include a terrestrial or non-terrestrial backhaul network, such as a satellite or a drone. In the following description, a case is described in which a satellite backhaul network in which the network delay value may change dynamically is used (or may be used). However, it is apparent to a person skilled in the art that the same / similar method may be applied even when a dynamically changing terrestrial backhaul network is used.

[0134] Upon determining that the type of backhaul network used (or that can be used) in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be changed dynamically, the AMF can notify the SMF. For example, the AMF can recognize that one or more types of backhaul networks can exist between the RAN and the core network (during the NG establishment process with the RAN). In this case, even if the backhaul network currently used in the control plane during the registration process of the UE is a terrestrial backhaul network, the AMF can determine that it is possible to change the backhaul network to a satellite backhaul network in the future, determine that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be changed dynamically, and notify the SMF of it.

[0135] As another example, the AMF may recognize that different types of backhaul networks may be used in the control plane and the user plane (during the NG establishment process with the RAN). In this case, even if the backhaul network currently used in the control plane during the registration process of the UE is a terrestrial backhaul network, the AMF may determine that there is a possibility that a satellite backhaul network may be used in the user plane, determine that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network whose network delay value can be changed dynamically, and notify the SMF thereof.

[0136] As another example, the AMF may recognize that different types of backhaul networks may be used in the control plane and the user plane (during the NG establishment process with the RAN). In this case, the AMF may determine that a different type of satellite backhaul network may be used in the user plane than the satellite backhaul network currently used in the control plane determined during the registration process of the UE (for example, NR (GEO) satellite backhaul may be used in the CP, while NR (LEO) satellite backhaul may be used in the UP), determine that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be changed dynamically, and notify the SMF thereof.

[0137] As another example, the AMF may identify that a satellite backhaul network connected by one or more satellites may be used between the RAN and the core network during the NG establishment process with the RAN or the registration process of the UE. In this case, the AMF may determine that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be changed dynamically, and notify the SMF thereof. When the AMF determines that the type of backhaul network used (or available) in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be changed dynamically, the AMF may notify the SMF that the delay value of the satellite backhaul network is dynamically changed, and may provide a dynamic satellite backhaul delay control request indication.

[0138] When the AMF determines that different types of backhaul networks can be used for the control plane and the user plane, and / or determines that a satellite backhaul network whose network delay value can be changed dynamically can be used for the user plane, and / or determines that the UPF can be selected based on the backhaul network delay value of the user plane, the AMF can send a global RAN node ID (RAN ID) and a dynamic satellite backhaul network delay control request indication to the SMF.

[0139] When it is determined that a satellite backhaul network in which the network delay value can be dynamically changed can be used in the control plane and / or the user plane, the AMF can send information for predicting the dynamic change mode, pattern, or period of the backhaul delay value to the SMF. For example, when it is determined that a satellite backhaul network including a mobile satellite constellation is used in the control plane and / or the user plane, when the backhaul network delay change pattern of the mobile satellite constellation can be predicted through information provided by the satellite operator, information provided by the RAN, or settings within the AMF, the AMF can send the information to the SMF.

[0140] As a specific example, in the case of a mobile satellite constellation, it can move with a specific period and orbit, and at a specific time interval, the connection between satellites can be far away or close, and at this time, the time period of the satellite constellation, or the specific time when the connection between satellites is temporarily far away or close can be sent to the SMF. The AMF can send information for predicting the dynamic change pattern, pattern or period of the return delay value and a dynamic satellite return network delay control request indication to the SMF. The SMF can determine the return network delay monitoring rules, etc. based on this information. As an embodiment, the dynamic satellite return network delay control request indication together with the satellite return category can be included in the message requesting the establishment of a PDU session (Nsmf_PDUSession_CreateSMContext request). As described above, the value of the satellite return category can be set to different values ​​depending on the type of satellite.

[0141] Step 3: SMF may request PCF to create a session management policy. As an embodiment, SMF may send a message (Npcf_SMPolicyControl_Create request) requesting PCF to create a session management policy.

[0142] After receiving the satellite backhaul category and / or the dynamic satellite backhaul delay control request from the AMF, the SMF may provide the satellite backhaul category and / or the dynamic satellite backhaul delay control request to the PCF. According to an embodiment, the SMF may include the satellite backhaul category and / or the dynamic satellite backhaul delay control request received from the AMF in a message requesting the creation of a session management policy (Npcf_SMPolicyControl_Create request) and send it to the PCF.

[0143] Even if the SMF receives or does not receive the satellite backhaul category and / or the dynamic satellite backhaul delay control request from the AMF, when it is determined that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be dynamically changed, the SMF can send a dynamic satellite backhaul delay control request to the PCF. According to an embodiment, even if the SMF does not receive the satellite backhaul category from the AMF, when the SMF receives the dynamic satellite backhaul delay control request, the SMF can send a dynamic satellite backhaul delay control request to the PCF.

[0144] As another example, even if the SMF has not received the satellite backhaul category from the AMF, when the SMF receives the dynamic satellite backhaul delay control request and the global RAN node ID (RAN ID) from the AMF, if it can be determined that the RAN indicated by the RAN ID is a RAN that can use different types of backhaul networks on the control plane and the user plane, or there are one or more types of backhaul networks that can be used on the control plane and / or the user plane, the SMF can send a dynamic satellite backhaul control request to the PCF. As another example, even if neither the satellite backhaul category nor the dynamic satellite backhaul delay control request is received from the AMF, when it is determined according to a preset method that the type of backhaul network that can be used in the control plane and / or the user plane is a satellite backhaul network in which the network delay value can be dynamically changed, the SMF can send a dynamic satellite backhaul delay control request to the PCF.

[0145] Even if the SMF receives or does not receive information from the AMF for predicting the dynamic change pattern, pattern or period of the backhaul delay value, the SMF can send this information to the PCF when the mobile satellite constellation can predict the backhaul network delay change pattern through information provided by the satellite operator, information provided by the RAN, information provided by the AMF, or setting information within the SMF.

[0146] Step 4: When the PCF receives the satellite backhaul category and / or dynamic satellite backhaul delay control request from the SMF, the PCF may create policy control and charging rules (PCC rules) taking into account the dynamic satellite backhaul network delay.

[0147] The PCC rule may include a QoS parameter, and the QoS parameter may include a packet delay budget (PDB), a packet error rate (PER), etc. For example, when the PCF receives a satellite backhaul category and a dynamic satellite backhaul delay control request from the SMF, the PCF may determine a QoS parameter value considering a network delay time that may occur in a satellite backhaul network of the type indicated by the satellite backhaul category, and may further determine an alternative QoS parameter value applicable when the satellite backhaul network delay time is longer or shorter than normal. For example, when determining the backhaul network delay allowed when passing through N satellites of the NR (LEO) type in consideration of the QoS requirements of the services provided to the user, the PCF may provide a packet delay budget value that may be allowed when one, two, or N NR (LEO) type satellites are involved as a QoS parameter or an alternative QoS parameter.

[0148] When the PCF receives a satellite backhaul classification and / or dynamic satellite backhaul delay control request from the SMF, the PCF may create a policy control request trigger condition, allowing the SMF to initiate a process for modifying policy control and charging rules taking into account the dynamic satellite backhaul network delay. When the SMF identifies that an event that satisfies the policy control request trigger condition has occurred, the SMF may request the PCF to modify the session management policy.

[0149] The policy control request trigger condition may include a situation where the SMF recognizes that the type of backhaul network used in the control plane and / or the user plane has changed. In this case, the SMF may provide the type of the backhaul network to the PCF after the change. For example, when the satellite backhaul category value received from the AMF is different from the previously received value, the SMF may recognize that the type of backhaul network used in the control plane and / or the user plane has changed, and may provide the changed value to the PCF. For example, if the satellite backhaul category value received from the AMF is different from the previously received value, the SMF recognizes that the type of backhaul network used in the control plane and / or the user plane has changed, and the changed value may be provided to the PCF.

[0150] The policy control request triggering condition may include the following situation: the SMF identifies the QoS parameters that can be met by the satellite backhaul network, and the network delay in the UPF in the satellite backhaul network can change dynamically. In this case, the SMF can provide the PCF with the QoS parameters that can be met and their values ​​(and / or QoS rule identifiers and / or PCC rule identifiers). In addition, the SMF can provide the PCF with the backhaul network delay value measured by the UPF.

[0151] An example of policy control request triggering information including at least one of the above policy control request triggering conditions may be Figure 4 Same as shown in .

[0152] The response message (Npcf_SMPolicyControl_Create response) to the message requesting the creation of a session management policy (Npcf_SMPolicyControl_Create request) may include PCC rules and / or policy control trigger conditions including a QoS parameter set (e.g., a QoS parameter set and / or an alternative QoS parameter set) for the above-mentioned dynamic satellite backhaul delay, and may be sent from the PCF to the SMF.

[0153] According to an embodiment, the session management policy creation response message (Npcf_SMPolicyControl_Create response) may further include QoS monitoring information for dynamic satellite backhaul delay control. An example of PCC rule information including QoS monitoring information for dynamic satellite backhaul delay control may be as follows: Figure 3 Same as shown in .

[0154] Step 5: The SMF may select a UPF considering the user plane backhaul network delay. For example, when the SMF receives a satellite backhaul category and / or a dynamic satellite backhaul delay control request from the AMF in step 2, the SMF may request a candidate UPF that can be searched by the SMF to measure the backhaul network delay of the RAN that can be connected via the GPRS tunnel protocol of the user plane (GTP-U) path, and may select a UPF suitable for the user plane based on the measured value. For example, the SMF may select a UPF that provides the network delay value of the shortest GTP-U path as a UPF suitable for the user plane.

[0155] When the AMF additionally provides a RAN ID (e.g., a global RAN node ID) in step 2, the SMF may provide the RAN ID to the candidate UPF to make a limited request to the candidate UPF to measure the network delay of the GTP-U path only for the corresponding RAN.

[0156] In the process of UPF measuring the backhaul network delay through the GTP-U path, when UPF sends an ECHO request message to the RAN connected through the GTP-U path, and the RAN that receives the ECHO response message sends an ECHO response message to UPF, UPF can measure the network delay of the GTP-U path based on the time required for UPF to send the ECHO request message and receive the ECHO response message. Each candidate UPF can provide the network delay of the GTP-U path measured by itself to SMF.

[0157] Step 6: SMF may request PCF to modify the session management policy. As an embodiment, SMF may send a message (Npcf_SMPolicyControl_Update request) to PCF requesting to modify the session management policy.

[0158] The SMF may determine from the UPF the QoS that can be satisfied by the network delay measurement value of the backhaul network used in the user plane (e.g., the network delay measurement value of the GTP-U path provided by the UPF selected in step 5), and may determine that the QoS parameters that can be satisfied by the satellite backhaul network (in which the network delay can be dynamically changed in the UPF) in the policy control request trigger condition provided by the PCF in step 4 correspond to the case where the SMF identifies the QoS parameters. In this case, the SMF may provide the PCF with the QoS parameters that can be satisfied, their values ​​(and / or QoS rule identifiers and / or PCC rule identifiers), and the network delay measurement value of the backhaul network used in the user plane. As an embodiment, the SMF may include the QoS parameters that can be satisfied and their values ​​(and / or QoS rule identifiers and / or PCC rule identifiers) (i.e., the selected QoS for dynamic satellite backhaul delay) and / or the network delay measurement value of the backhaul network used in the user plane (i.e., the measured backhaul delay) in the message requesting modification of the session management policy (Npcf_SMPolicyControl_Update request), and send it to the PCF.

[0159] Step 7: The PCF may maintain or modify the PCC rules provided in step 4, and provide the PCC rules to the SMF taking into account the network delay of the backhaul network used in the user plane and the information about the QoS that can be met, and provide the PCC rules to the SMF.

[0160] When the PCF receives the dynamic satellite backhaul delay control request in step 3, the PCF may provide the SMF with PCC rule information including QoS monitoring information for controlling dynamic satellite backhaul delay. QoS monitoring for dynamic satellite backhaul control may include QoS parameters to be measured, reporting frequency and / or thresholds. An example of PCC rule information including QoS monitoring information for dynamic satellite backhaul delay control may be as follows: Figure 3 Same as shown in .

[0161] The PCF may consider the network delay of the backhaul network used in the user plane and the information about the QoS that can be satisfied, and provide the SMF with a policy control request trigger condition for QoS monitoring for dynamic satellite backhaul delay control. An example of the policy control request trigger information including the above policy control request trigger condition may be as follows: Figure 4 Same as shown in .

[0162] The policy control request triggering condition for QoS monitoring for dynamic satellite backhaul delay control may be associated with the reporting condition (QoS monitoring information) indicated by the PCC rule information. For example, assuming that the QoS parameter to be measured is the round-trip packet delay, the reporting frequency is when the packet delay exceeds the threshold and the threshold is 100ms, the SMF may recognize that when the QoS monitoring result received from the UPF and / or the RAN includes a round-trip packet delay exceeding 100ms, the policy control request triggering condition for QoS monitoring for dynamic satellite backhaul delay control is met, and provide the round-trip packet delay value to the PCF.

[0163] The PCC rule information including the above-mentioned QoS monitoring information for dynamic satellite backhaul delay control and / or the policy control request triggering condition for QoS monitoring for dynamic satellite backhaul delay control may be included in a response message (Npcf_SMPolicyControl_Update response) to a message (Npcf_SMPolicyControl_Update request) requesting a session management policy modification, and sent from the PCF to the SMF. As an embodiment, the response message (Npcf_SMPolicyControl_Update response) may also include a policy control request triggering condition for QoS monitoring for dynamic satellite backhaul delay control and another policy control request triggering condition.

[0164] Step 8: SMF can request UPF to establish or modify N4 session.

[0165] Step 9: When the SMF receives QoS monitoring for dynamic satellite backhaul control from the PCF, the SMF may provide the RAN with a QoS monitoring indication, a QoS monitoring reporting frequency and / or a QoS monitoring threshold during the PDU session establishment / modification process. For example, based on the QoS monitoring information for dynamic satellite backhaul delay control received from the PCF in step 7, the SMF may provide the RAN with a QoS monitoring indication, a QoS monitoring reporting frequency and / or a QoS monitoring threshold to measure the network delay of the N3 part (the user plane interface part between the RAN and the UPF). The RAN may perform GTP-U path monitoring on the UPF based on the received information (e.g., the method described in step 5). The description of the QoS monitoring indication (QoS Monitoring Indication), the QoS Monitoring Reporting Frequency and the QoS Monitoring Threshold may refer to, for example, the above reference. Figure 3 Describes the QoS monitoring indication, QoS monitoring report frequency, and QoS monitoring threshold.

[0166] Step 10: AMF may transmit the information received in step 9 to RAN.

[0167] Step 11: RAN may accept the PDU session establishment request received from SMF and send information related thereto to the UE, and may perform AN resource establishment.

[0168] Step 12: In response to the QoS monitoring request of the SMF received through steps 9 to 10, the RAN may determine acceptance or rejection in QoS flow units, and may notify the SMF of the accepted or rejected QoS flow identifier through the AMF. For example, when the internal load of the RAN is high, the RAN may refuse to perform QoS monitoring for dynamic satellite backhaul delay control on some or all QoS flows using the same N3 interval backhaul network.

[0169] Step 13: AMF may transmit the information received from RAN to SMF.

[0170] Step 14a: The SMF may send an N4 session modification request message (N4 Session Modification Request) to the UPF based on the QoS flow of the RAN accepting the PDU session establishment. In this case, based on the QoS monitoring information for dynamic satellite backhaul delay control received from the PCF in step 7, the SMF may provide the UPF with a QoS monitoring policy for dynamic satellite backhaul delay control in order to measure the network delay of the N3 part (the user plane interface part between the RAN and the UPF). For example, as described above with reference to Figure 3 As described, when SMF receives QoS monitoring for dynamic satellite backhaul control from PCF, SMF can provide QoS monitoring strategy to UPF during PDU session establishment / modification process. In this case, SMF can determine QoS monitoring strategy based on QoS monitoring information for controlling dynamic satellite backhaul delay received from PCF.

[0171] The QoS monitoring policy may include QoS parameters to be measured, reporting frequencies, thresholds, reporting targets and / or indications of direct event notifications. Each value may be determined by the SMF based on the value provided by the PCF. For example, upon receiving an indication of NWDAF and direct event notification as a reporting target value from the PCF, the SMF may provide the same indication to the UPF to allow the UPF to report the measurement value directly to the NWDAF. Such an example may be implemented if the PCF intends to analyze the dynamic change pattern of the satellite backhaul network through the NWDAF and refer to it to determine the PCC rules based on the request of the AF or the PCF's own judgment.

[0172] The UPF may perform GTP-U path monitoring on the RAN based on the received information (the method described in step 5).

[0173] The SMF may determine to reject the PDU session establishment based on the QoS flow that the RAN accepts or rejects for the QoS monitoring request for dynamic satellite backhaul delay control. For example, if there is no alternative method because there are no other UEs or other PDU sessions that can be monitored for the backhaul network in the N3 part of the transmission of the rejected QoS flow, the SMF may determine to reject the PDU session establishment request.

[0174] Step 14b: UPF may send an N4 session modification response message corresponding to the N4 session modification request message to SMF.

[0175] Step 15: SMF may respond to step 13 to AMF.

[0176] Step 16: Based on the QoS flows accepted or rejected by the QoS monitoring request for dynamic satellite backhaul delay control received from the RAN in step 12, after determining in step 14a that the PDU session establishment is rejected, the SMF may notify the AMF of this.

[0177] Figure 6 is a view showing the structure of a UE according to an embodiment.

[0178] Reference Figure 6 ,The UE may include a transceiver 610, a controller 620, and a memory 630. In the present disclosure, the controller may be defined as a circuit or an application specific integrated circuit or at least one processor.

[0179] The transceiver 610 may send and receive signals to and from other network entities. The transceiver 610 may receive system information from, for example, a base station, and may receive a synchronization signal or a reference signal.

[0180] According to an embodiment, the controller 620 may control the overall operation of the terminal. For example, the controller 620 may control the inter-block signal flow to perform the above Figure 1 To the operation of Figure 5. Specifically, the controller 620 may control the operations as provided in the present disclosure to support the method for session management based on a dynamic backhaul network according to the embodiment.

[0181] The memory 630 may store at least one of information transmitted / received via the transceiver 610 and information generated via the controller 620. For example, the memory 630 may store information for executing the Figure 1 Information / data / commands to the operation of Figure 5.

[0182] Figure 7 The structure of a base station according to an embodiment of the present disclosure is shown.

[0183] refer to Figure 7, the base station may include a transceiver 710, a controller 720, and a memory 730. In the present disclosure, the controller may be defined as a circuit or an application specific integrated circuit or at least one processor.

[0184] The transceiver 710 may send signals to and receive signals from other network entities. For example, the transceiver 710 may send system information to the UE and may send a synchronization signal or a reference signal.

[0185] According to an embodiment, the controller 720 may control the overall operation of the base station. For example, the controller 720 may control the inter-block signal flow to perform the above Figure 1 To the operation of Figure 5. Specifically, the controller 720 may control the operations as provided in the present disclosure to support the method for session management based on a dynamic backhaul network according to the embodiment.

[0186] The memory 730 may store at least one of information transmitted / received via the transceiver 710 and information generated via the controller 1020. For example, the memory 730 may store information for executing the Figure 1 Information / data / commands to the operation of Figure 5.

[0187] Figure 8 The structure of a network function entity according to an embodiment of the present disclosure is shown.

[0188] Figure 8 The network entity may be, for example, Figure 1 To one of the AMF, UPF, SMF or PCF entities of Figure 5.

[0189] Reference Figure 8 , the network entity may include a transceiver 810, a controller 820, and a memory 830. In the present disclosure, a controller may be defined as a circuit or an application specific integrated circuit or at least one processor.

[0190] The transceiver 810 may send signals to and receive signals from other network entities. For example, the transceiver 810 may send / receive data and request / response to / from other network entities.

[0191] According to one embodiment, the controller 820 may control the overall operation of the base station. For example, the controller 820 may control the inter-block signal flow to perform the above Figure 1 To the operation of Figure 5. Specifically, the controller 1120 may control the operations provided in the present disclosure to support the method for session management based on a dynamic backhaul network according to the embodiment.

[0192] In the above specific embodiments, the components included in the present disclosure are represented in singular or plural form, depending on the specific embodiment provided. However, the singular or plural form is selected to be sufficient for the context suggested for ease of description, and the present disclosure is not limited to singular or plural components. As used herein, the singular forms "a", "an", and "the" are intended to also include plural forms, unless the context clearly indicates otherwise.

[0193] The embodiments of this document are provided only for a better understanding of the present disclosure, and the present disclosure should not be limited thereto. In other words, it is obvious to those skilled in the art that various changes may be made to it without departing from the scope of the present disclosure. In addition, the embodiments may be implemented in combination. For example, a base station and a UE may operate in a combination of an embodiment and a component of another embodiment. In addition, other modifications based on the technical spirit of the above-described embodiments may be implemented in various systems, such as FDD LTE systems, TDD LTE systems, and 5G or NR systems.

[0194] 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

1. A method for a session management function SMF in a wireless communication system, the method include: receiving a first message from an access and mobility management function, AMF, the first message comprising information indicating that a dynamic satellite backhaul is used; as well as Based on receiving the first message, a second message is sent to a policy control function PCF, the second information indicating that the dynamic satellite backhaul is used, wherein the PCF triggers a quality of service QoS monitoring operation for the dynamic satellite backhaul based on the second message.

2. The method according to claim 1, further comprising: include: In response to sending the second message, a third message is received from the PCF, wherein the third message includes policy control and charging PCC rule information and policy control request trigger condition information related to the SMF.

3. The method according to claim 2, in, The PCC rule information includes QoS monitoring information for dynamic satellite backhaul delay control, and wherein the QoS monitoring information includes at least one of the following: information indicating at least one QoS parameter to be measured; Information indicating the frequency of reporting; information indicating a threshold value associated with the at least one QoS parameter to be measured; Information indicating the target of the report; or Information indicating whether to notify the event directly.

4. The method according to claim 3, in, The PCC rule information also includes at least one of a QoS parameter set or an alternative QoS parameter set for the dynamic satellite backhaul delay control.

5. The method according to claim 2, in, The policy control request trigger condition information related to the SMF includes at least one of the following: a first policy control request triggering condition for the SMF to identify a situation where QoS parameters are satisfied over a satellite backhaul network where network delays are dynamically changing in a user plane function UPF; as well as The second policy control request triggering condition is for QoS monitoring for dynamic satellite backhaul delay control.

6. The method of claim 1 , further comprising selecting the UPF based on a latency of a backhaul network associated with a user plane.

7. The method according to claim 2, further comprising: include: Sending a session management policy modification request message to the PCF, wherein the session management policy modification request message includes a measured value of a delay of a backhaul network associated with a user plane; as well as A session management policy modification response message including the PCC rule information and the policy control request triggering condition information is received from the PCF.

8. The method according to claim 3 further includes sending at least one of QoS monitoring indicator information, QoS monitoring report frequency information or QoS monitoring threshold information generated based on the QoS monitoring information to the AMF.

9. The method according to claim 6, further comprising sending QoS monitoring policy information generated based on the QoS monitoring information to the UPF, in, The QoS monitoring policy information is used by the UPF to measure the network delay of the N3 part.

10. The method according to claim 1, in, The first message includes satellite backhaul category information and a dynamic satellite backhaul delay control request indicator.

11. A session management function SMF device in a wireless communication system, the device include: Transceiver; as well as a controller coupled to the transceiver, the controller being configured to: receiving a first message from an access and mobility management function, AMF, the first message comprising information indicating that dynamic satellite backhaul is used, and Based on receiving the first message, a second message is sent to a policy control function PCF, wherein the second information indicates that the dynamic satellite backhaul is used, wherein the PCF triggers a quality of service QoS monitoring operation for the dynamic satellite backhaul based on the second message.

12. The device according to claim 11, in, The controller is further configured to operate according to the method of any one of claims 2 to 10.

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