Method and device for managing data transmission on basis of mobility of terminal 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 embodiment of the present disclosure, a method of a session management function (SMF) entity in a wireless communication system comprises the steps of: receiving, from an access and mobility management function (AMF) entity, a first message including a session management (SM) container, wherein the SM container includes result information of admission control for a quality of service (QoS) flow of a packet data unit (PDU) session; and transmitting a second message including result information of the admission control to a policy control function (PCF) entity, wherein the result information of the admission control includes information indicating whether PDU set QoS parameters are applicable to the QoS flow or PDU QoS parameters are applicable to the QoS flow.

Description

Method and device for managing data transmission based on terminal mobility in a wireless communication system

[0001] The present disclosure relates to a method and device for managing data transmission based on the mobility of a terminal in a wireless communication system, and more specifically, to a communication method for smoothly transmitting data traffic according to the status of a base station during handover when considering an XR (extended reality) service that supports QoS (quality of service) at the application level.

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

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

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

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

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

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

[0008] The present disclosure provides a communication method and device for smoothly managing data transmission by reflecting the status of a base station during handover when using QoS that reflects application-level characteristics to well satisfy the user's perceived performance when performing ultra-high-speed, low-latency communication such as XR service in a wireless communication system.

[0009] According to one embodiment of the present disclosure, a method of a session management function (SMF) entity in a wireless communication system includes the steps of: receiving, from an access and mobility management function (AMF) entity, a first message including a session management (SM) container, wherein the SM container includes result information of admission control for a quality of service (QoS) flow of a packet data unit (PDU) session; and transmitting a second message including result information of the admission control to a policy control function (PCF) entity, wherein the result information of the admission control includes information indicating whether a PDU set QoS parameter or a PDU QoS parameter is applied to the QoS flow.

[0010] According to one embodiment of the present disclosure, in a wireless communication system, a session management function (SMF) entity includes a transceiver; and at least one processor, wherein the at least one processor is configured to receive, from an access and mobility management function (AMF) entity, a first message including a session management (SM) container, wherein the SM container includes result information of admission control for a quality of service (QoS) flow of a packet data unit (PDU) session, and transmit a second message including result information of the admission control to a policy control function (PCF) entity, wherein the result information of the admission control includes information indicating whether a PDU set QoS parameter or a PDU QoS parameter is applied to the QoS flow.

[0011] FIG. 1 is a diagram showing an example of a transmission path of data traffic during handover in a wireless communication system according to an embodiment of the present disclosure.

[0012] FIG. 2 is a flowchart illustrating a method in which an application server provides and applies PDU Set-level QoS information and policies to a 5G network in a wireless communication system according to an embodiment of the present disclosure.

[0013] FIG. 3a and FIG. 3b are flowcharts illustrating a method for performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0014] FIG. 4a and FIG. 4b are flowcharts illustrating a method of performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0015] FIG. 5a and FIG. 5b are flowcharts illustrating a method of performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0016] FIG. 6 is a flowchart illustrating a method of performing a handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0017] FIG. 7 is a flowchart illustrating a method of performing a handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0018] FIG. 8 is a flowchart illustrating a method of performing handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0019] FIG. 9 is a structural diagram showing the structure of a network entity according to an embodiment of the present disclosure.

[0020] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0021] For the same reason, some components in the attached drawings are omitted or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect the actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0022] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the present disclosure is complete and to fully 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 claims. Like reference numerals refer to like elements throughout the specification.

[0023] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0024] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0025] The term '~part' used in this embodiment means a software or hardware component, and the '~part' performs certain roles. However, the '~part' is not limited to software or hardware. The '~part' may be configured to reside on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and '~parts' may be combined into a smaller number of components and '~parts' or further separated into additional components and '~parts'. In addition, the components and '~parts' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card. Additionally, in the embodiment, '~bu' may include one or more processors.

[0026] In the present disclosure, a user equipment (UE) may be referred to as a terminal, MS (Mobile Station), cellular phone, smartphone, computer, or various electronic devices capable of performing communication functions.

[0027] Furthermore, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types to those described below. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0028] In specifically explaining the embodiments of the present disclosure, the communication system may use various wired or wireless communication systems, for example, the 3rd generation partnership project (3GPP), a wireless communication standard standardization organization, may use the New RAN (NR), which is a wireless access network in the 5G communication standard, and the Packet Core (5G System, or 5G Core Network, or NG Core: Next Generation Core), which is a core network. In addition, it may be applied to other communication systems with similar technical backgrounds with slight modifications within a range that does not significantly deviate from the scope of the present disclosure, and this will be possible at the discretion of a person skilled in the art of the present disclosure.

[0029] The terms used in the description of the present disclosure below to identify connection nodes, terms referring to network entities (NFs), terms referring to messages, terms referring to interfaces between NFs (Network Functions), terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0030] 5G systems support network slices, and traffic for different network slices can be processed by different PDU (protocol data unit) sessions. The PDU session may refer to an association between a data network providing a PDU connection service and a terminal. The network slice can be understood as a technology that logically configures a network as a set of network functions (NFs) to support various services with different characteristics, such as broadband communication services, massive IoT, and mission-critical services such as V2X, and separates different network slices. Therefore, even if a communication failure occurs in a network slice, the communication in other network slices is not affected, enabling the provision of stable communication services. In the present disclosure, "slice" may be used interchangeably with the term "network slice." In such a network environment, a terminal can connect to multiple network slices when receiving various services. In addition, the network function (NF) may be implemented as a network element as a software instance running on hardware or as a virtualized function instantiated on an appropriate platform.

[0031] A mobile communication operator can configure the above network slices and allocate network resources suitable for specific services for each network slice or for each set of network slices. The above network resources may refer to NFs, logical resources provided by the NF, or wireless resource allocation of a base station.

[0032] For example, a mobile communication operator can configure network slice A to provide a mobile broadband service, network slice B to provide a vehicle communication service, and network slice C to provide an XR service to be described later. That is, in this way, a 5G network can efficiently provide the corresponding service to a terminal through a network slice specialized according to the characteristics of each service. In a 5G system, a network slice can be represented by S-NSSAI (Single-Network Slice Selection Assistance Information). The S-NSSAI can include an SST (Slice / Service Type) value and an SD (Slice Differentiator) value. The SST can indicate the characteristics of a service supported by the network slice (e.g., enhanced mobile broadband (eMBB), IoT, URLLC (ultra reliability low latency communication), V2X, XR service, etc.). The SD can be a value used as an additional identifier for a specific service referred to as SST.

[0033] Services that require services characterized by high transmission speed and low latency (HDRLL; High Data Rate Low Latency) include, for example, extended reality (XR) services, augmented reality (AR) services, virtual reality (VR) services, or cloud gaming services. The VR service is a service that provides a virtual environment implemented by a computer device using a VR headset, etc. The AR service is a service that can combine a virtual environment with the real world using location, geographic information, etc. The XR service is a service that can not only combine a real environment and a virtual environment, but also provide the user with information such as touch, hearing, and smell, thereby enhancing the user's sense of experience.

[0034] In describing the communication service providing the above-described Application-based QoS in the present disclosure, the embodiments of the present disclosure are described based on XR services for convenience. However, the present disclosure is applicable not only to XR services but also to various data services. Therefore, it should be noted that the embodiments of the present disclosure are not limited to XR services.

[0035] According to the present disclosure, when various types of XR service data such as audio, video, and haptic are transmitted to a user, packets corresponding to the Application Data Unit (ADU) of the Application must be transmitted to the terminal according to the characteristics of the Application to become meaningful information. At this time, therefore, if a packet belonging to an ADU is not transmitted properly or the transmission of a certain packet fails, even if the transmitted packet belonging to the ADU is transmitted to the terminal, there are cases where the ADU information is not transmitted to the user. At this time, if the packet that cannot be properly displayed to the terminal is not transmitted through the communication network, resources for transmitting unnecessary packets are saved, which can help the performance of the communication network.

[0036] In addition, when the traffic of an application serving a user is generated as ADUs according to the characteristics of the media, and the packets corresponding to the ADUs are transmitted through the communication network, each ADU can have a correlation with each other according to the characteristics of the media. For example, a certain ADU is very important and contains information that is absolutely necessary when transmitting the information to the user, and in the case of some ADUs, even if the packets corresponding to the ADU are transmitted to the terminal without the important ADU, they cannot be seen by the user. In this way, the relationship and importance with other ADUs can be determined according to the ADU. For example, when packets of a certain ADU are transmitted, packets of an ADU with a lower importance but higher relationship than the ADU above are scheduled with a lower priority in scheduling and packet processing, or the packets can be discarded when necessary. As described above, when processing packets using the application-level information, the resources used in the network can be effectively used to improve the user's service experience.

[0037] The above ADU can be viewed as a collection of PDUs (packet data units) in a communication network, and thus can be called a PDU set. In describing the present disclosure, the ADU and PDU set can be used interchangeably, but can be understood as basically the same concept. However, in the case of ADU, it can be viewed as a unit of application data transmitted outside of a communication network, and when ADU is serviced within a communication network, it can be referred to as a PDU set.

[0038] When packets corresponding to the above PDU Set are serviced in a communication network, QoS processing is performed based on the QoS parameters given at the existing packet (i.e., PDU) level. For example, the QoS parameters include information such as packet delay budget (PDB) or packet error rate (PER). At this time, when the QoS processing at the application level, i.e., the PDU Set QoS parameters given at the PDU Set level, are supplied from the policy and charge function (PCF) or the application function (AF), the PDU Set QoS parameters corresponding to the QoS parameters are given, and the QoS is provided based on the PDU Set QoS parameters. For example, the PDU Set QoS parameters include information such as PSDB (PDU set delay budget) or PSER (PDU set error rate) or PSIHI (PDU set integrated handling indicator).

[0039] That is, even if PDB is given as a QoS parameter for a QoS Flow, if PSDB is given as a PDU Set QoS parameter, the base station can schedule and service the data of the Qos flow to satisfy PSDB instead of PDB. Or, even if PER is given as a QoS parameter for a QoS Flow, if PSER is given as a PDU Set QoS parameter, the base station can schedule and service the data of the Qos flow to satisfy PSER instead of PER.

[0040] In addition, in order to process the above PDU Set level QoS processing in the communication network, in the case of downlink data, PDU Set information is found out from the PSA (PDU session anchor) UPF of the communication network, and the PDU Set information is forwarded by including it in the GTP-U header, thereby enabling PDU Set level QoS processing within the communication network (e.g., RAN, etc.).

[0041] FIG. 1 is a diagram showing an example of a transmission path of data traffic during handover in a wireless communication system according to an embodiment of the present disclosure.

[0042] Figure 1 shows the transmission paths for XR data traffic and the transmission paths for transmitting related control messages for processing traffic services based on PDU Set QoS in a situation where XR data traffic scheduling based on PDU Set is performed through a source NG-RAN (next generation-radio access network) during a handover and then moves to a target NG-RAN.

[0043] In the present disclosure, the network technology may refer to standard specifications defined by the International Telecommunication Union (ITU) or 3GPP (e.g., 3GPP TS 23.501, TS 23.502, TS 23.503, etc.), and the components included in the network structure of Fig. 1 may each mean a physical entity, or may mean software or hardware combined with software that performs an individual function. In the drawings, reference symbols shown as Nx, such as N1, N2, N3, ..., represent known interfaces between NFs in a 5G core network (CN), and since a related description may refer to the standard specification (TS 23.501), a detailed description thereof will be omitted. In addition, since a basic related description of the handover procedure may refer to the standard specification (TS 23.502 or TS 38.300), a detailed description of the handover procedure in the present disclosure may be omitted as necessary.

[0044] The wireless communication system of Fig. 1 includes a radio access network (NG-RAN) and a 5G core network (5GC). The NG-RAN may be a base station (e.g., gNB, IAB (Integrated Access and Backhaul), etc.) that supports radio access technology in the 5G system. In the case where a terminal moves from a serving NG-RAN (or source NG-RAN) where it was previously receiving service to a target NG-RAN to receive service, there may be differences in the QoS handling functions according to the PDU Set in the serving NG-RAN and the target NG-RAN. For example, if the serving NG-RAN applies PDU Set QoS, the target NG-RAN may not support the PDU Set, or even if the target NG-RAN supports PDU Set QoS, it may be difficult to sufficiently satisfy the PDU Set QoS requested for the QoS flow in the serving NG-RAN due to insufficient resources.

[0045] Accordingly, it is necessary to take measures such as modifying the values ​​of the PDU Set QoS parameters applied compared to the requested values, not accepting the corresponding QoS flows, or applying the QoS parameters without applying the PDU Set QoS parameters, and, if necessary, signaling for control such as notifying the application server of changes in the processing of the corresponding service traffic in the wireless communication system.

[0046] In Fig. 1, 5GC may include network entities such as AMF (Access and Mobility Management Function), SMF (Session Management Function), UPF (User Plane Function), PCF (Policy Control Function), UDM (Unified Data Management) (not shown).

[0047] The AMF is an entity that manages terminal access and mobility. The AMF can serve as a terminal-core network endpoint, connecting terminals to other entities in the 5GC via NG-RAN. For example, the AMF can perform network functions such as terminal registration, connection, reachability, mobility management, access verification, authentication, and mobility event generation.

[0048] The above SMF can perform management functions for the PDU (Protocol Data Unit) sessions of the terminal. For example, the SMF can perform network functions such as session management functions through the establishment, modification, and termination of sessions and the maintenance of tunnels between the UPF and NG-RAN required for this purpose, terminal IP (Internet Protocol) address allocation and management functions, user plane selection and control, UPF traffic processing control, and charging data collection control.

[0049] The above UPF performs the role of processing user data of the terminal (e.g., XR data), and can perform the role of processing XR data so that XR data generated by the terminal can be transmitted to the AF / AS or data received from the AF / AS can be transmitted to the terminal. For example, the UPF can perform network functions such as acting as an anchor between radio access technologies (RATs), providing connection between PDU sessions and AF / AS, routing and forwarding packets, inspecting packets, applying user plane policies, creating traffic usage reports, and buffering.

[0050] The above UDM can perform functions such as generating authentication information for 3GPP security, processing user identifiers (User IDs), managing a list of network functions (NFs) supporting terminals, and managing subscription information. The UDR (Unified Data Repository) can perform functions such as storing and providing subscription information managed by the UDM, structured data for exposure, NEF (Network Exposure Function), or application data associated with services.

[0051] The PCF is an NF that manages operator policy information for providing services in a 5G system. The UDR can store terminal subscription information and provide the subscription information to the UDM. In addition, the UDR can store the operator policy information and provide the operator policy information to the PCF. The NEF can be responsible for the function of transmitting or receiving external information about events occurring in the 5G system and supported capabilities. For example, the NEF can perform functions such as safely providing AF / AS information to the 5GC, converting internal / external information, and storing and redistributing information received from other NFs in the UDR.

[0052] A terminal can connect to the NG-RAN and register with the 5G system. For example, a terminal can connect to the NG-RAN and perform a terminal registration procedure with the AMF. During the registration procedure, the AMF can determine a network slice available to the terminal connected to the NG-RAN and allocate it to the terminal. The terminal can select a network slice and establish a PDU session for communication with the AF / AS. One PDU session can include one or more Quality of Service (QoS) Flows, and each QoS Flow can provide different transmission performance required for each application service by setting different QoS parameters. In addition, through handover, data forwarding from the serving NG-RAN to the target NG-RAN and data traffic forwarded from the UPF to the target NG-RAN for QoS flows for which service is allowed in the target NG-RAN are scheduled and transmitted to the terminal according to the received QoS profile or QoS parameters. In particular, when PDU Set QoS parameters are provided for the above QoS flow and QoS handling for the PDU Set is performed, according to the embodiment of the present disclosure, the value for performing PDU set-based QoS handling, the corresponding QoS flow can be modified, or the corresponding QoS flow can be deleted, or changed to use PDU-based QoS parameters so that the service can be made available even during handover.

[0053] In addition, the application server (AF) can transmit the values ​​of the PDU Set QoS parameters required for the corresponding service to the communication network. At this time, if the AF is outside the trusted domain, the PDU Set QoS parameters values ​​can be transmitted to the PCF through the NEF, and if the AF is within the trusted domain, the PDU Set QoS parameters values ​​can be directly transmitted to the PCF to apply the PDU Set-based handling as described above. In addition, at this time, the application server can transmit to the PCF a policy on how to handle cases where the NG-RAN does not sufficiently support PDU Set QoS.

[0054] FIG. 2 is a flowchart illustrating a method in which an application server provides and applies PDU Set level QoS information and policies to a 5G network in a wireless communication system according to an embodiment of the present disclosure.

[0055] Referring to FIG. 2, this is for a case where an application server (AF) provides information on the characteristics of application data traffic, for example, a case where PDU Set QoS parameters and protocol descriptions are provided to a 5G network via NEF. FIG. 2 describes an operation of performing admission control and notifying the application server (AF or AS) of the applied admission control method when, in this case, PDU Set handling is applied in a 5G network, even if the RAN supports the PDU Set handling function, it is difficult to satisfy the PDU Set QoS parameters for the QoS flow for the application.

[0056] At step 200, a PDU Session can be created for the XR service.

[0057] In step 201, the AF may transmit to the NEF, via the Nnef_AFSessionWithQoS_Create request message, the PDU Set QoS Parameter and Protocol description, which are service requirement information for data traffic transmitted from the application server. In one embodiment, the Nnef_AFSessionWithQoS_Create request message may include a PDU Set based admission control policy indicating that admission control is required based on the PDU Set.

[0058] At step 202, NEF may perform authentication for the request.

[0059] In step 203, NEF can send the PDU Set QoS Parameter and Protocol description to PCF via Npcf_PolicyAuthorization_Create request message.

[0060] In step 204, PCF may send NEF an Npcf_PolicyAuthorization_Create response message in response to step 203.

[0061] In step 205, the NEF may send an Nnef_AFSessionWithQoS_Create response message to the AF in response to step 201. In one embodiment, instead of the process from step 201 to step 205, if an update is required for the existing service requirements, such as PDU Set QoS Parameter and Protocol description or PDU Set based admission control policy, the AF may transmit the updated information to the NEF through the Nnef_AFSessionWithQoS_Update message in step 201, and the NEF may transmit the updated PDU Set QoS Parameter and Protocol description information and PDU Set based admission control policy to the PCF through the Npcf_PolicyAuthorization_Update process in step 203. In step 206, the PCF, which has received and authenticated the information, may transmit an SM policy association modification request message to the SMF to update the SM policy for the corresponding QoS flow. In one embodiment, the SM policy association modification request message may include a PDU Set QoS parameters value.

[0062] In one embodiment, the SM policy association modification request message may include a PDU Set based admission control policy for indicating that PDU Set based admission control is required from AF according to the application's policy, or, when PDU Set QoS parameters values ​​are given, a PDU Set based admission control policy that is an indication that PDU Set based admission control is required according to the 5G network operator's policy.

[0063] Accordingly, the PDU Session modification procedure can be performed as in steps 206 to 213.

[0064] The information included in the above PDU Set based admission control policy may directly indicate information about the admission control method to be used, or may not specifically indicate the admission control method to be used but may directly indicate that PDU Set based admission control is required, or may indirectly indicate that PDU Set based admission control is required by transmitting PDU Set QoS Parameters without directly sending the PDU Set based admission control policy as described above.

[0065] Accordingly, the PDU Set based admission control policy can be delivered by the AF as in step 201, or even if the PCF does not receive the PDU Set based admission control policy from the AF, the PCF can apply the PDU Set based admission control policy on its own according to the operator's policy or local policy if the PCF receives the PDU Set QoS parameter. In addition, the PDU Set based admission control policy can be delivered by the PCF as in step 206, or even if the SMF does not receive the PDU Set based admission control policy from the PCF, the SMF can apply the PDU Set based admission control policy on its own according to the operator's policy or local policy if the SMF receives the PDU Set QoS parameter.

[0066] Additionally, the PDU Set based admission control policy may be delivered by the SMF as in step 208, or even if the RAN does not receive the PDU Set based admission control policy from the SMF, the RAN may apply the PDU Set based admission control policy itself according to the operator's policy or local policy when the RAN receives the PDU Set QoS parameter.

[0067] In one embodiment, although FIG. 2 illustrates that a PDU session is established at step 200 and steps 201 to 205 are performed, a PDU session may be established at the request of a UE after steps 201 to 205 are performed. In this case, the operations of steps 206 to 213 are similar to those described above, but the transmission message may be different.

[0068] In one embodiment, if the PDU session is established after steps 201 to 205 are performed, the PDU Session establishment procedure may be performed instead of the PDU Session modification procedure, such as steps 206 to 213.

[0069] When the PDU Session establishment procedure is performed, the terminal can transmit a PDU Session establishment request message to the SMF via the AMF. After that, the SMF transmits an SM (session management) policy establishment request or SM policy update request message to the PCF using the S-NSSAI (single network slice selection assistance information) and DNN (data network name) information requested in the request, and the PCF can transmit the SM policy to the SMF.

[0070] At this time, information such as PDU Set QoS parameters and PDU Set based admission control policy can be transmitted to the SMF for the QoS flow to which the PDU Set is applied. The SMF can transmit an N2 SM message to the RAN according to the received SM policy to transmit the QoS profile and PDU Set based admission control policy for the service flow, or perform a PDU Session establishment request process such as transmitting a PDU Session establishment accept message to the UE through an N1 SM message, etc.

[0071] FIG. 3a and FIG. 3b are flowcharts illustrating a method for performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0072] Referring to FIGS. 3a and 3b, the Source RAN is a base station supporting the PDU Set handling function, as in step 300a, and the Target RAN is a base station supporting the PDU Set handling function, as in step 300b. In step 300c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 300c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 300d.

[0073] Steps 301 to 304 below describe the handover preparation procedure.

[0074] In step 301, the Source RAN determines that a handover is required, and in case of Xn handover, it may transmit a HO request message to the Target RAN as in step 302. The HO request message may include information about a PDU Session served by the Source RAN, and in particular, information about QoS flows served through the PDU Session. In one embodiment, the HO request message may include a QoS profile including a QoS parameter for a QoS flow and a PDU Set QoS parameter, and if a PDU Set based admission control policy is a policy received from an SMF, the HO request message may include the PDU Set based admission control policy.

[0075] In step 303, the Target RAN can determine whether handover is possible by considering the Target RAN's resources, etc., for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions. In particular, admission control can be performed according to the PDU Set admission control policy for QoS flows to which PDU Set QoS parameters are applied.

[0076] In one embodiment, a method according to a PDU Set admission control policy may be such that, if it is determined that the Target RAN does not sufficiently satisfy the PSDB or PSER among the PDU Set QoS parameters for the QoS flow, the Target RAN may modify the PSDB value or PSER value to a level that the Target RAN can satisfy, reject handover of the QoS flow, or not apply PDU Set handling to the QoS flow and instead operate based on the QoS parameter, even though the Target RAN supports the PDU Set handling function.

[0077] In step 304, the Target RAN may inform the Source RAN of information about QoS flows and PDU Sessions that accept handover according to the admission control or information about QoS flows and PDU Sessions for which handover is rejected through a HO request ACKnowledge message. In one embodiment, the HO request Ack message may include information about processing of a PDU Set QoS parameter, for example, a modified PDU Set QoS parameter (modified PSDB value or modified PSER value), an indication that the target RAN supports the PDU Set handling function, or an admission control result such as the target RAN deciding not to apply PDU Set handling.

[0078] In step 305, the Source RAN initiates a handover for the terminal, and in step 306, the terminal can complete the handover to the Target RAN.

[0079] In step 307, the Target RAN may transmit an N2 path switch request message to the AMF. In one embodiment, the N2 SM container in the N2 path switch request message may include an indication indicating that the PDU Set function is supported for a QoS flow that performs PDU Set handling. In particular, the N2 SM container may include an admission control result for modifying a PSDB value or a PSER value that the Target RAN can satisfy, rejecting a handover of the QoS flow, or not applying PDU Set handling to the QoS flow but instead operating based on QoS parameters, depending on the admission control result in step 303.

[0080] In step 308, the AMF may send a Nsmf_PDUSessionUpdateSMContext request message to the SMF / UPF, and the N2 SM container within the Nsmf_PDUSessionUpdateSMContext request message may include the above indication and admission control results. Accordingly, the SMF may perform UPF and N4 session updates, and may modify the data transmission path by sending an Nsmf_PDUSessionUpdateSMContext response and an N2 Path Switch request ACK to the target RAN through the AMF, as in steps 309 and 310.

[0081] At step 311, the target RAN may release resources to the source RAN as the handover is complete.

[0082] Meanwhile, the SMF that received the admission control result in step 308 can forward the received admission control result (modified PSDB value or PSER value, reject handover of the QoS flow, or apply QoS parameter instead of PDU Set handling for the QoS flow) to the PCF through an SM policy association modification or Notification message, such as step 312 or step 313.

[0083] In steps 314 and 315, if the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 300c, the PCF may directly transmit the admission control result (modified PSDB value or PSER value, rejecting handover of the QoS flow, or applying QoS parameter instead of PDU Set handling for the QoS flow) to the AF, for example, by including it in a Nnef_AFSessionWithQoS Notify message, or the like. Accordingly, the AF may modify the data transmission speed or data encoding method for the XR service according to the situation of the 5G network based on the reported Notify message.

[0084] FIG. 4a and FIG. 4b are flowcharts illustrating a method for performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0085] Referring to FIGS. 4a and 4b, the Source RAN is a base station that supports the PDU Set handling function, as in step 400a, and the Target RAN is a base station that does not support the PDU Set handling function, as in step 400b. In step 400c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 400c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the Source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 400d.

[0086] Steps 401 to 404 below describe a handover preparation procedure. In step 401, the Source RAN determines that a handover is necessary, and in case of an Xn handover, it may transmit a HO request message to the Target RAN as in step 402. The HO request message may include information about a PDU Session served by the source RAN, and in particular, information about QoS flows served through the PDU Session. In one embodiment, the HO request message may include a QoS profile including a QoS parameter for a QoS flow and a PDU Set QoS parameter, and if a PDU Set based admission control policy is a policy received from an SMF, the HO request message may include the PDU Set based admission control policy.

[0087] However, since the target RAN is a base station that does not have the function of handling PDU Sets as described in step 400b, it can ignore the function and policy information related to PDU Sets transmitted in the HO request of step 402. Accordingly, in step 403, the target RAN can determine whether handover is possible by considering the resources of the target RAN for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions through the legacy method.

[0088] In step 404, the target RAN can inform the source RAN of information about QoS flows and PDU Sessions that accept handover according to the admission control, or information about QoS flows and PDU Sessions for which handover is rejected, through the HO request ACKnowledge message. In one embodiment, the HO request Ack message does not contain any information about processing of the PDU Set QoS parameter, so the source RAN can indirectly detect that the target RAN does not support PDU Set handling or that the PDU Set QoS parameter is not applied, as in step 405.

[0089] At step 406, the Source RAN initiates a handover for the terminal, and at step 409, the terminal can complete the handover to the Target RAN.

[0090] Meanwhile, if the Source RAN detects that PDU Set handling is no longer applied in the Target RAN, as in step 405, the Source RAN can send a notification to the SMF through the AMF in steps 407 and 408, including the N2 SM container of the N2 Notify message and the Namf_Communication N1N2Trasnfer message, informing that PDU Set handling is no longer applied to the corresponding QoS flow.

[0091] In steps 410 and 411, the Target RAN may transmit a data transmission path modification request to the SMF. Accordingly, the SMF may perform UPF and N4 session updates, and may modify the data transmission path by transmitting an Nsmf_PDUSessionUpdateSMContext response and an N2 Path Switch request ACK to the Target RAN through the AMF, as in steps 413 and 414.

[0092] At step 415, the Target RAN may release resources to the Source RAN as the handover is complete.

[0093] Meanwhile, even if the QoS flow is to apply the PDU Set QoS parameter and the PDU Set based admission control policy, as in step 412, the SMF recognizes that the PDU Set handling is not applied to the Target RAN through steps 407 and 408. Accordingly, the SMF may reject the handover of the QoS flow or apply the QoS parameter instead of the PDU Set handling to the QoS flow. In step 416 or step 417, the SMF may transmit the received admission control result (i.e., reject the handover of the QoS flow or apply the QoS parameter instead of the PDU Set handling to the QoS flow) to the PCF through an SM policy association modification or Notification message.

[0094] In steps 418 and 419, if the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 400c, the PCF may directly transmit the admission control result (rejecting handover of the QoS flow or applying QoS parameter instead of PDU Set handling for the QoS flow) to the AF or through the NEF, for example, by including it in the Nnef_AF SessionWithQoS Notify message. Accordingly, the AF may modify the data transmission speed or data encoding method for the XR service depending on the situation of the 5G network based on the reported Notify message.

[0095] FIGS. 5a and 5b are flowcharts illustrating a method of performing handover and notifying an application server by considering the PDU Set function during Xn handover in a wireless communication system according to an embodiment of the present disclosure.

[0096] Referring to FIGS. 5a and 5b, the Source RAN is a base station that supports the PDU Set handling function, as in step 500a, and the Target RAN is a base station that does not support the PDU Set handling function, as in step 500b. In step 500c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 500c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the Source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 500d.

[0097] Steps 501 to 504 below describe a handover preparation procedure. In step 501, the Source RAN determines that a handover is necessary, and in case of an Xn handover, it may transmit a HO request message to the Target RAN as in step 502. The HO request message may include information about a PDU Session served by the source RAN, and in particular, information about QoS flows served through the PDU Session. In one embodiment, the HO request message may include a QoS profile including a QoS parameter for a QoS flow and a PDU Set QoS parameter, and if a PDU Set based admission control policy is a policy received from an SMF, the HO request message may include the PDU Set based admission control policy.

[0098] However, since the target RAN is a base station that does not have the function of handling PDU Sets as described in step 500b, it can ignore the function and policy information related to PDU Sets transmitted in the HO request of step 502. Accordingly, in step 503, the target RAN can determine whether handover is possible by considering the resources of the target RAN for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions through the legacy method.

[0099] In step 504, the target RAN can inform the source RAN of information about QoS flows and PDU Sessions that accept handover according to the admission control, or information about QoS flows and PDU Sessions for which handover is rejected, through the HO request ACKnowledge message. In one embodiment, the HO request Ack message does not contain any information about handling of the PDU Set QoS parameter, so the source RAN can indirectly detect, as in step 505, that the target RAN does not support PDU Set handling or that the PDU Set QoS parameter is not applied.

[0100] In step 506, the Source RAN initiates a handover for the terminal, and in step 507, the terminal can complete the handover to the Target RAN.

[0101] In steps 508 and 509, the target RAN may transmit a data transmission path modification request to the SMF. Accordingly, the SMF may perform UPF and N4 session updates, and may modify the data transmission path by transmitting an Nsmf_PDUSessionUpdateSMContext response and an N2 Path Switch request ACK to the target RAN through the AMF, as in steps 511 and 512.

[0102] At step 515, the Target RAN may release resources to the Source RAN as the handover is complete.

[0103] Meanwhile, even if the QoS flow is to apply the PDU Set QoS parameter and the PDU Set based admission control policy as in step 510, the SMF indirectly recognizes that the Target RAN does not support PDU Set Handling and therefore PDU Set handling is not applied, as an indication notifying that PDU Set handling is supported is not received in steps 508 and 509. Accordingly, the SMF may reject the handover of the QoS flow, or apply the QoS parameter instead of PDU Set handling to the QoS flow, and in step 514, the SMF, PCF, NEF, and AF may perform the same operations as steps 416 to 419 of FIG. 4. That is, the SMF can convey the admission control result (i.e., rejecting the handover of the QoS flow, or applying QoS parameters instead of PDU Set handling for the QoS flow) received through the SM policy association modification or Notification message to the PCF.

[0104] When the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 500c, the PCF can directly deliver the admission control result (rejecting handover of the QoS flow or applying QoS parameter instead of PDU Set handling for the QoS flow) to the AF, for example, by including it in a Nnef_AFSessionWithQoS Notify message, or through the NEF. Accordingly, the AF can modify the data transmission speed or data encoding method for the XR service depending on the situation of the 5G network based on the reported Notify message.

[0105] FIG. 6 is a flowchart illustrating a method of performing handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0106] Referring to FIG. 6, the Source RAN is a base station that supports the PDU Set handling function, as in step 600a, and the Target RAN is a base station that supports the PDU Set handling function, as in step 600b. In step 600c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 600c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the Source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 600d.

[0107] Steps 601 to 611 below describe the handover preparation procedure.

[0108] In step 601, the source RAN determines that a handover is required, and in the case of an N2 handover, it may transmit a HO required message to the source AMF as in step 602. In one embodiment, the HO required message may include information for data forwarding for the PDU Session ID and QoS flow being serviced by the source RAN.

[0109] In steps 603 and 604, the N2 SM information including the PDU Session IDs allowed to the SMF and the information included in the HO required message can be transmitted through the source AMF and the target AMF. In steps 605 and 606, the SMF can transmit the PDU Session ID and the N2 SM information including the QoS parameter, the PDU Set QoS parameter information, and the PDU Set based admission control policy information to the target RAN through the target AMF.

[0110] In step 607, the Target RAN may determine whether handover is possible by considering the resources of the Target RAN, etc., for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions. In one embodiment, the Target RAN may perform admission control for a QoS flow to which PDU Set QoS parameters are applied according to the PDU Set admission control policy.

[0111] For example, a method according to the PDU Set admission control policy is to determine that the target RAN does not sufficiently satisfy the PSDB or PSER among the PDU Set QoS parameters for the QoS flow, and the target RAN modifies the PSDB value or PSER value to a level that the target RAN can satisfy, even though the PDU Set handling function is supported, or to reject the handover of the QoS flow, or to not apply the PDU Set handling to the QoS flow and instead operate based on the QoS parameter.

[0112] In steps 608 and 609, the target RAN may include information about QoS flows and PDU Sessions that accept handover according to the admission control, or information about QoS flows and PDU Sessions for which handover is rejected, in the N2 SM information, and notify the SMF through the target AMF. The HO request Ack message of step 608 may include an indication in the N2 SM information that the target RAN supports the PDU Set handling function, and may include information about processing of PDU Set QoS parameters, for example, modified PDU Set QoS parameters (modified PSDB value or modified PSER value) that the target RAN can satisfy, or may include the result of the admission control of step 607, such as rejecting the handover of the QoS flow, or the target RAN deciding not to apply PDU Set handling.

[0113] In step 609, the Target AMF can transmit the above indication and admission control results to the SMF via the Nsmf_PDUSessionUpdateSMContext request message through the N2 SM container.

[0114] In step 610, the SMF may send a Nsmf_PDUSessionUpdateSMContext response message to the Target AMF, and in step 611, the Target AMF may send a Namf_Communication_CreateUEContext response to the Source AMF.

[0115] When the preparation process for N2 handover is completed up to step 611, the Source AMF can perform the handover by sending a Handover command message to the source RAN in step 612. Meanwhile, if the SMF, which received the admission control result in step 609, recognizes that the terminal has been handed over to the target RAN in step 612, the SMF / UPF and PCF / NEF / AF can perform the operations of steps 312 to 315 of FIG. 3 in step 613. That is, the SMF can deliver the received admission control result (modified PSDB value or PSER value, or rejecting the handover of the QoS flow or applying QoS parameter instead of PDU Set handling for the QoS flow) to the PCF through an SM policy association modification or Notification message.

[0116] When the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 600c, the PCF directly or through the NEF transmits the admission control result (modified PSDB value or PSER value, or rejecting handover of the QoS flow, or applying QoS parameter instead of PDU Set handling for the QoS flow) to the AF by including it in, for example, a Nnef_AFSessionWithQoS Notify message. Accordingly, the AF can modify the data transmission speed or data encoding method for the XR service depending on the situation of the 5G network based on the reported Notify message.

[0117] FIG. 7 is a flowchart illustrating a method of performing handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0118] Referring to FIG. 7, the Source RAN is a base station that supports the PDU Set handling function, as in step 700a, and the Target RAN is a base station that does not support the PDU Set handling function, as in step 700b. In step 700c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 700c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the Source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 700d.

[0119] In step 701, the Source RAN determines that a handover is necessary and can perform the preparation process for N2 handover. Meanwhile, since the Target RAN does not support the PDU Set handling function as in step 700b, the PDU Set-related parameters are ignored in the preparation process.

[0120] Accordingly, the target RAN determines whether handover is possible by considering the resources of the target RAN for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions through the existing method.

[0121] After completing the above N2 handover preparation process, the source AMF performs the handover process by sending a handover command message to the source RAN, as in step 702.

[0122] Additionally, in step 701, the target RAN notifies the SMF through the target AMF of information about QoS flows and PDU Sessions that accept handover according to the above admission control or information about QoS flows and PDU Sessions for which handover is rejected, and the SMF can notify the source RAN through the source AMF through N2 SM information as in step 2.

[0123] At this time, since the HO command message of step 702 does not contain any information about the processing of the PDU Set QoS parameter, the source RAN can indirectly detect that the target RAN does not support PDU Set handling or that the PDU Set QoS parameter is not applied, as in step 703.

[0124] In step 706, the Source RAN initiates a handover for the terminal, in step 707, the terminal completes the handover to the Target RAN, and in step 708, the Target RAN may transmit a Handover Notify message to the Target AMF.

[0125] Meanwhile, if the Source RAN detects in step 703 that PDU Set handling is no longer applied in the Target RAN, the Source RAN can include a notification in the N2 SM container informing that PDU Set handling is no longer applied for the corresponding QoS flow and forward it to the Source AMF and SMF in steps 704 and 705.

[0126] The Target AMF, which receives the HO notify message in step 708, can notify the Source AMF in step 709 and forward the N2 SM information to the SMF in step 710. Therefore, in step 711, the SMF can recognize the processing status for the PDU Session and the QoS flow. In step 712, the SMF can send the Nsmf_PDUSessionUpdateSMContext response message to the Target AMF. In step 714, the remaining handover finalization process, such as the Target AMF releasing resources for the Source RAN and the Source AMF, can be performed.

[0127] Meanwhile, even if the QoS flow is to apply the PDU Set QoS parameter and the PDU Set based admission control policy, as in step 711, the SMF recognizes that the PDU Set handling is not applied to the Target RAN through steps 74 and 75. Accordingly, the SMF may reject the handover of the QoS flow, or apply the QoS parameter instead of the PDU Set handling to the QoS flow.

[0128] In step 713, SMF / UPF and PCF / NEF / AF may perform steps 416 to 419 of FIG. 4. That is, SMF may forward the admission control result received (i.e., rejecting handover of the QoS flow or applying QoS parameters instead of PDU Set handling for the QoS flow) to PCF via SM policy association modification or Notification message.

[0129] When the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 700c, the PCF can directly or through the AF to transmit the admission control result (rejecting the handover of the QoS flow, applying the QoS parameter instead of PDU Set handling for the QoS flow) to the AF by including it in, for example, a Nnef_AFSessionWithQoS Notify message. Accordingly, the AF can modify the data transmission speed or data encoding method for the XR service depending on the situation of the 5G network based on the reported Notify message.

[0130] FIG. 8 is a flowchart illustrating a method of performing handover and notifying an application server by considering the PDU Set function during N2 handover in a wireless communication system according to an embodiment of the present disclosure.

[0131] Referring to FIG. 8, the Source RAN is a base station that supports the PDU Set handling function, as in step 800a, and the Target RAN is a base station that does not support the PDU Set handling function, as in step 800b. In step 800c, the application server (AF) provides the PDU Set QoS Parameters, which are QoS requirements necessary for servicing the corresponding application, to the 5G network, and if the above requirements are not satisfied, the PDU Set admission control policy, which is a policy to be processed for the corresponding flow, can also be provided to the 5G network, and accordingly, a modification process for the PDU Session can be performed to apply the above QoS requirements. For reference, in step 800c, the processes from step 200 to step 213 of FIG. 2 are performed, and accordingly, the Source RAN can apply PDU Set handling to the QoS flow that has received the PDU Set QoS parameters, as in step 800d.

[0132] Steps 801 to 807 below describe the handover preparation procedure.

[0133] In step 801, the preparation process for N2 handover can be performed as in steps 601 to 606 of FIG. 6. Meanwhile, since the target RAN does not support the PDU Set handling function as in step 800b, the PDU Set-related parameters are ignored in the preparation process, and the target RAN can determine whether handover is possible by considering the resources of the target RAN for the PDU Sessions to be handed over and the QoS flows of the PDU Sessions through the existing method.

[0134] Thereafter, in steps 803 and 804, the target RAN may include information about QoS flows and PDU Sessions that accept handover according to the existing admission control, or information about QoS flows and PDU Sessions for which handover is rejected, in the N2 SM information and notify the SMF through the target AMF using the HO request ACKnowledge message and the Nsmf_PDUSessionUpdateSMContext request. In addition, in step 803, the target RAN does not include an indication in the N2 SM information that the target RAN supports the PDU Set handling function according to step 800b.

[0135] In step 805, even if the SMF is a QoS flow that applies the PDU Set QoS parameter and the PDU Set based admission control policy, it can indirectly recognize that the Target RAN does not support PDU Set Handling and therefore PDU Set handling is not applied, through the fact that no indication indicating that the Target RAN supports PDU Set handling was received in steps 803 and 804.

[0136] In step 806, the SMF may send the Nsmf_PDUSessionUpdateSMContext response message to the Target AMF, and in step 807, the Target AMF may send the Namf_Communication_CreateUEContext response message to the Source AMF to complete the preparation process for the N2 handover. In steps 808 and 809, and in steps 811 and 812, the handover process may be performed.

[0137] Meanwhile, if the SMF recognizes that the handover to the target RAN has occurred by receiving the Nsmf_PDUSessionUpdateSMContext request message at step 809, the SMF / UPF, PCF / NEF / AF can perform the operations of steps 416 to 419 of FIG. 4 at step 810. That is, the SMF can transmit the received admission control result (rejecting the handover of the QoS flow, or applying QoS parameters instead of PDU Set handling for the QoS flow) to the PCF through an SM policy association modification or Notification message.

[0138] When the PCF receives a PDU Set QoS parameter or a PDU Set based admission control policy from the AF as in step 800c, the PCF may directly or through the AF to transmit the admission control result (rejecting the handover of the QoS flow or applying the QoS parameter instead of PDU Set handling for the QoS flow) to the AF by including it in, for example, a Nnef_AFSessionWithQoS Notify message. Accordingly, the AF may modify the data transmission speed or data encoding method for the XR service depending on the situation of the 5G network based on the reported Notify message.

[0139] FIG. 9 is a structural diagram illustrating the structure of a network entity according to one embodiment of the present disclosure.

[0140] The network entities illustrated in FIG. 9 may include network entities mentioned in the present disclosure, such as SMF, PCF, NEF, and UPF.

[0141] A network entity according to one embodiment of the present disclosure may include a transceiver (910) including a transmitter and a receiver that control the overall operation of the network entity, a memory (920), and a control unit (930). Of course, the present invention is not limited to the above example, and the network node may include more or fewer components than the configuration illustrated in FIG. 9.

[0142] According to one embodiment of the present disclosure, the transceiver (910) can transmit and receive signals with network entities or other network nodes. The signals transmitted and received with the network entities can include control information and data. In addition, the transceiver (910) can receive signals, output them to the control unit (930), and transmit the signals output from the control unit (930).

[0143] The memory (920) can store programs and data necessary for the operation of the terminal. In addition, the memory (920) can store control information or data included in signals transmitted and received by the terminal. The memory (920) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there can be multiple memories (920).

[0144] The control unit (930) may control a series of processes to enable the network entity to operate according to the embodiments of the present disclosure described above. The control unit (930) may include at least one processor, and the series of processes to enable the network entity to operate may be performed by each of at least one processor belonging to the control unit, or by a combination thereof.

[0145] When the network entity is an SMF entity, at least one processor included in the control unit (930) can be controlled to receive a PDU session request message including information on an admission control policy based on a packet data unit (PDU) set from a policy control function (PCF) entity. The at least one processor can be controlled to transmit information on the admission control policy based on the PDU set to a source RAN (radio access network). The at least one processor can be controlled to receive an SM container from a target RAN. In one embodiment, the SM container can include result information on admission control for a quality of service (QoS) flow of a PDU session based on the admission control policy based on the PDU set.

[0146] In one embodiment, information about the admission control policy based on the PDU set may instruct the RAN to perform admission control on the QoS flow of the PDU session.

[0147] In one embodiment, the result information of the admission control is characterized in that the Target RAN modifies the PDU set QoS parameter for the QoS flow of the PDU session, rejects handover of the QoS flow, or indicates that the PDU set QoS parameter is not applied to the QoS flow and that the PDU QoS parameter is applied.

[0148] The at least one processor may be configured to receive an SM container from the Source RAN. The at least one processor may be configured to perform the admission control on the QoS flow if the SM container includes information indicating that PDU Set-based QoS flow control is not applied.

[0149] The at least one processor may be configured to reject a handover of the QoS flow. The at least one processor may be configured to determine that the PDU set QoS parameter is not applied to the QoS flow and that the PDU QoS parameter is applied.

[0150] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0151] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0152] These programs (software modules, software) may be stored in a non-volatile memory including random access memory, flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0153] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0154] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0155] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method of SMF (session management function) entity in a wireless communication system, A step of receiving a first message including a session management (SM) container from an access and mobility management function (AMF) entity, wherein the SM container includes result information of admission control for a quality of service (QoS) flow of a packet data unit (PDU) session; and A step of transmitting a second message including result information of the permission control to a PCF (policy control function) entity; A method characterized in that the result information of the above admission control includes information indicating whether the PDU set QoS parameter or the PDU QoS parameter is applied to the QoS flow.

2. In paragraph 1, the result information of the permission control is: A method characterized in that it includes at least one of: a PDU set QoS parameter modified by a target RAN (radio access network) for the QoS flow of the PDU session, information indicating that handover of the QoS flow is rejected, or information indicating that the PDU set QoS parameter is not applied to the QoS flow and that the PDU QoS parameter is applied.

3. In paragraph 1, A step of receiving a PDU session request message including information on an admission control policy based on the PDU set from a PCF (policy control function) entity; and A step of transmitting information about an admission control policy based on the PDU set to the source RAN; A method characterized in that the result information of the above permission control is based on information about the above permission control policy.

4. In the third paragraph, information on the admission control policy based on the PDU set is A method characterized by instructing the RAN to perform admission control for the QoS flow of the PDU session.

5. In paragraph 1, The above first message includes a PDU session update request message, A method characterized in that the second message includes an SM policy association modification message or a notification message.

6. In paragraph 1, A method characterized in that the first message includes an indicator indicating whether the PDU Set function is supported for the QoS flow.

7. In paragraph 1, A method characterized by comprising: a step of performing a session update with a UPF (user plane function) entity based on result information of the above admission control.

8. In paragraph 1, A method characterized in that the result information of the above permission control is transmitted to an AF (application function) entity.

9. In a wireless communication system, for the SMF (session management function) entity, Transmitter and receiver; and comprising at least one processor; wherein the at least one processor comprises: Receiving a first message from an AMF (access and mobility management function) entity, wherein the first message includes a session management (SM) container, wherein the SM container includes result information of admission control for a quality of service (QoS) flow of a PDU (packet data unit) session, and It is configured to transmit a second message including result information of the above admission control to a PCF (policy control function) entity, An SMF entity characterized in that the result information of the above admission control includes information indicating whether a PDU set QoS parameter or a PDU QoS parameter is applied to the QoS flow.

10. In paragraph 9, the result information of the permission control is: An SMF entity characterized in that it includes at least one of: a PDU set QoS parameter modified by a target RAN (radio access network) for the QoS flow of the PDU session, information indicating that handover of the QoS flow is rejected, or information indicating that the PDU set QoS parameter is not applied to the QoS flow and that the PDU QoS parameter is applied.

11. In the 9th paragraph, at least one processor, Receive a PDU session request message including information about an admission control policy based on the PDU set from a PCF (policy control function) entity, and It is configured to transmit information about the admission control policy based on the above PDU set to the source RAN, An SMF entity characterized in that the result information of the above permission control is based on information about the above permission control policy.

12. In paragraph 11, information on the admission control policy based on the PDU set is An SMF entity characterized by instructing the RAN to perform admission control for the QoS flow of the PDU session.

13. In paragraph 9, The above first message includes a PDU session update request message, An SMF entity characterized in that the second message includes an SM policy association modification message or a notification message.

14. In paragraph 13, An SMF entity characterized in that the first message includes an indicator indicating whether the PDU Set function is supported for the QoS flow.

15. In the 9th paragraph, at least one processor, It is configured to perform a session update with a UPF (user plane function) entity based on the result information of the above permission control, and An SMF entity characterized in that the result information of the above permission control is transmitted to an AF (application function) entity.

Images