Method and apparatus for selecting network for transmitting data traffic of terminal in wireless communication system using femto base station

Abstract

The present disclosure relates to a method and an apparatus for efficiently selecting a network for transmitting data traffic of a terminal in a wireless communication system using a femto base station. A method performed by an AMF in a wireless communication system supporting a femto system, according to embodiments of the present disclosure, comprises the steps of: receiving, from the femto base station to which the terminal is connected in the femto system, first information related to the femto system and a PDU session establishment request message for the terminal; selecting, on the basis of the first information, an SMF for managing a PDU session of the terminal; and transmitting, on the basis of the first information, a PDU session generation request message to the selected SMF.

Description

Method and device for selecting a network for transmitting data traffic of a terminal in a wireless communication system using a femto base station

[0001] The present disclosure relates to a method and device for providing a communication service to a terminal through a femto base station in a wireless communication system.

[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] When providing services by installing a femto base station in a wireless communication system, a femto system can be constructed that includes a local SMF or local UPF, including the femto base station. The femto system is intended to enable 5G communication services in a narrow area, such as a single floor of a house or building. The femto system allows consumers / users to purchase and install a femto system to receive high-quality 5G communication services, for example, without the communication service provider directly installing the base station. When providing communication services to terminals connected to the femto system through the femto system's local data network, there may be an advantage in that traffic from the macro data network can be offloaded to the local data network.

[0009] In this disclosure, we propose a method for a business operator to control data traffic for a terminal connected to a wireless network via a femto base station, such as determining whether to service / provide data traffic on a local data network or on a macro data network.

[0010] The present disclosure provides a method and device for efficiently selecting a network for transmitting data traffic of a terminal in a wireless communication system using a femto base station.

[0011] The present disclosure provides a method and device for establishing a PDU session of a terminal in a wireless communication system supporting a femto system.

[0012] The present disclosure provides a method and device for efficiently transmitting data traffic of a terminal using at least one of a local data network and a macro data network in a wireless communication system.

[0013] According to an embodiment of the present disclosure, a method performed by an AMF in a wireless communication system supporting a femto system includes the steps of receiving first information related to the femto system and a PDU session establishment request message for the terminal from a femto base station to which a terminal is connected in the femto system, the steps of selecting an SMF for managing a PDU session of the terminal based on the first information, and the steps of transmitting a PDU session creation request message to the selected SMF based on the first information.

[0014] In addition, according to an embodiment of the present disclosure, a method performed by an SMF in a wireless communication system supporting a femto system includes a process of receiving a PDU session creation request message including information related to the femto system from an AMF that has received a PDU session establishment request from a femto base station to which a terminal in the femto system has accessed, a process of performing an authentication procedure for use of the femto system through a PCF that manages policy information, and a process of selecting a UPF that processes data traffic of the terminal in the femto system based on the authentication result and the information related to the femto system.

[0015] In addition, according to an embodiment of the present disclosure, in a wireless communication system supporting a femto system, an AMF includes a transceiver, and a processor configured to receive, through the transceiver, first information related to the femto system from a femto base station to which a terminal is connected in the femto system and a PDU session establishment request message for the terminal, select an SMF for managing a PDU session of the terminal based on the first information, and transmit, through the transceiver, a PDU session creation request message to the selected SMF based on the first information.

[0016] In addition, according to an embodiment of the present disclosure, in a wireless communication system supporting a femto system, an SMF includes a transceiver, and a processor configured to receive, through the transceiver, a PDU session creation request message including information related to the femto system from an AMF that has received a PDU session establishment request from a femto base station to which a terminal in the femto system is connected, perform an authentication procedure for using the femto system through a PCF that manages policy information, and select a UPF that processes data traffic of the terminal in the femto system based on the authentication result and the information related to the femto system.

[0017] FIG. 1a is a diagram illustrating an example of a network structure for a wireless communication system;

[0018] FIG. 1b is a diagram illustrating an example of the structure of a wireless communication system supporting a femto system according to an embodiment of the present disclosure;

[0019] FIG. 1c is a diagram illustrating an example of the structure of a wireless communication system supporting a femto system according to an embodiment of the present disclosure;

[0020] FIG. 2 is a diagram illustrating a method for providing terminal policy information (UE POLICY) for using a femto system to a terminal in a wireless communication system supporting a femto system according to an embodiment of the present disclosure;

[0021] FIG. 3A and FIG. 3B are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) for a terminal connected through a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0022] FIG. 4a and FIG. 4b are diagrams illustrating a method for creating a PDU session based on subscription information of a terminal connected to a network through a femto system according to an embodiment of the present disclosure;

[0023] FIG. 5a and FIG. 5b are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) of a terminal connected to a network through a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0024] FIG. 6a and FIG. 6b are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) for a terminal connected to a network through a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure, and

[0025] FIG. 7 is a diagram showing the configuration of a network entity in a wireless communication system according to an embodiment of the present disclosure.

[0026] 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.

[0027] 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 its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0028] 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 with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The various embodiments are provided to ensure that the present disclosure is complete and to fully convey the scope of the present disclosure to those skilled in the art, and the present disclosure is defined solely by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0029] 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).

[0030] 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.

[0031] The term "~unit" used in various embodiments of the present disclosure refers to a software or hardware component, and the "~unit" performs certain roles. However, the "~unit" is not limited to software or hardware. The "~unit" 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 "~unit" 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 "~units" may be combined into a smaller number of components and "~units" or further separated into additional components and "~units." In addition, the components and "~units" may be implemented to regenerate one or more CPUs within a device or a secure multimedia card. Additionally, in various embodiments of the present disclosure, '~bu' may include one or more processors.

[0032] In this disclosure, phrases such as "A and / or B", "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", or "first" or "second" may be used merely to distinguish the corresponding component from other corresponding components and do not limit the corresponding components in any other respect (e.g., importance or order).

[0033] In various embodiments of the present disclosure, a terminal may be referred to as a user equipment (UE), a terminal, a mobile station (MS), a cellular phone, a smartphone, a computer, or any other electronic device capable of performing a communication function.

[0034] Furthermore, the various embodiments of the present disclosure described below may be applied to other communication systems having similar technical backgrounds or channel configurations. Furthermore, the various 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.

[0035] In specifically explaining various embodiments of the present disclosure, the communication system may utilize a wireless communication system, and for example, the 3GPP, a wireless communication standard standardization organization, may utilize NR (New RAN), a wireless access network, and Packet Core (5G System, or 5G Core Network, or NG Core (Next Generation Core)), a core network, in the 5G communication standard. 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.

[0036] The above-described wireless access network, RAN (Radio Access Network), can be installed in a macro network and can also be installed through a femto base station of a femto system. In embodiments of the present disclosure, the femto base station can be referred to by various terms, such as, for example, Femto gNB (next Generation Node B) or F-gNB or Home gNB or H-gNB or Femto NG-RAN or F-NG-RAN, and at least one of the above-described terms can be used interchangeably. In addition, the femto system can be composed of only Femto gNBs, or can be composed of UPFs (User Plane Functions) in addition to Femto gNBs. In addition, in embodiments of the present disclosure, the UPFs constituting the femto system can be referred to as local UPFs or L-UPFs or Femto UPFs or F-UPFs, and at least one of the above-described terms can be used interchangeably. Alternatively, the femto system can include at least one of a SMF (Session Management Function) and UPFs in addition to the femto gNB. At this time, in the embodiments of the present disclosure, the SMF constituting the femto system may be referred to as a local SMF or an L-SMF or a Femto SMF or an F-SMF, and at least one of the above-mentioned terms may be used interchangeably.

[0037] The terms used in the various embodiments of the present disclosure below to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network functions (NFs), terms referring to various identification information, etc. are provided 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.

[0038] 5G systems support network slices, and traffic for different network slices can be processed by different protocol data unit (PDU) sessions. A PDU session may refer to an association between a data network providing a PDU connection service and a terminal. A network slice can be understood as a technology that logically configures a network as a set of Network Functions (NFs) (or network entities) to support various services with different characteristics, such as broadband communication services, massive IoT, V2X, and other mission-critical services, 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, so stable communication services can be provided. In various embodiments of the present disclosure, "slice" may be used interchangeably with the term "network slice." In such a network environment, a terminal may access multiple network slices when receiving various services. The above NF may be a software instance running on hardware, or may be implemented as a virtualized function instantiated on a network element or an appropriate platform. Of course, the above examples are not limited to this, and the NF may be configured as an independent piece of hardware, or may be configured as a combination of software and hardware.

[0039] Mobile operators can configure network slices and allocate network resources appropriate for specific services, either individually or across network slices. Network resources can include NFs, logical resources provided by NFs, or radio resources allocated by base stations.

[0040] For example, a mobile communication operator can configure network slice A to provide a mobile broadband service, network slice B to provide a vehicular communication service, and network slice C to provide an eXtended Reality (XR) service, which will 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 the 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 the SST.

[0041] Hereinafter, various embodiments of the present disclosure will be described with reference to the drawings.

[0042] In the present disclosure, network technology may refer to standard specifications defined by the International Telecommunication Union (ITU) or 3GPP (e.g., TS 23.501, TS 23.502, TS 23.503, etc.), and components included in the network structure of FIG. 1A may mean physical entities, or may mean software performing individual functions, or hardware combined with software. Reference numerals shown as N1, N2, N3, ..., Nxxx, etc. in the drawings represent known interfaces between NFs in a 5G core network (CN).

[0043] For convenience of explanation, some terms and names defined in the 3rd generation partnership project long-term evolution (3GPP) standards may be used. However, the present disclosure is not limited to these terms and names, and can be equally applied to systems conforming to other standards.

[0044] FIG. 1a is a diagram illustrating an example of a network structure for a wireless communication system.

[0045] The wireless communication system of FIG. 1A is an example of a 5G system, and the 5G system may include a 5GC (5G core network), a base station (105), and a terminal (100). 5GC may include an Access and Mobility Management Function (AMF) (110) for managing the mobility of a terminal (100), a Session Management Function (SMF) (115) for managing a session, a User Plane Function (UPF) (120) for performing a data transmission role by being connected to a data network (DN) (125), a network slice selection function (NSSF) (125) for selecting a network slice that services the terminal (100), an Authentication Server Function (AUSF) (130) for performing authentication of network entity(ies) in a 5G system, a Network Exposure Function (NEF) (170) for transmitting or receiving events occurring in the 5G system and capabilities supported therein to the outside, a network repository function (NRF) (150) for managing registration information of NFs, a policy control function (PCF) (155) for providing a policy control function of a network operator, and a user data management (UDM) (160) for providing a data management function such as subscriber data and policy control data. , and the AF (Application Function) (170) providing application services can communicate with the 5GC. In the example of FIG. 1, the 5GC is not limited to the above example, and the 5GC may include more or fewer network entities than the example of FIG. 1.

[0046] The above AMF (110) is an entity for managing access and mobility of the terminal (100). For example, the AMF (110) can perform network functions such as registration, connection, reachability, mobility management, access confirmation, authentication, and mobility event generation of the terminal (100). In addition, the AMF (110) can serve as a terminal-core network endpoint that connects the terminal to other network entity(ies) of the 5GC of the macro system or femto system via the F-gNB.

[0047] The above SMF (115) can perform a management function for a PDU (Protocol Data Unit) session of the terminal (101). For example, the SMF (115) can perform network functions such as a session management function through establishing, modifying, and releasing a session, maintaining a tunnel between the UPF (120) and the base station (105), an IP (Internet Protocol) address allocation and management function of the terminal (100), user plane selection and control, traffic processing control in the UPF (120), and charging data collection control.

[0048] The UPF (120) may perform a data processing function to transmit data transmitted by the terminal (100) to the external network DN (125) or to transmit data received from the DN (125) to the terminal (100). In addition, the UPF (120) may perform network functions such as performing an anchor role between radio access technologies (RATs), providing a connection between a PDU session and an AF (170), packet routing and forwarding, packet inspection, applying a user plane policy, creating a traffic usage report, buffering, etc.

[0049] The PCF (155) manages operator policy information for providing services in a 5G system, and the UDM (160) can perform functions such as generating authentication information for 3GPP security, managing a list of network functions (NFs) supporting the terminal (100), and managing subscription information. The Unified Data Repository (UDR) (not shown) can perform functions such as storing and providing subscription information managed by the UDM (160), structured data for exposure, and application data associated with the Network Exposure Function (NEF) (140) or services. In addition, the UDR can store the terminal's subscription information and provide the stored subscription information to the UDM (160). In addition, the UDR can store operator policy information and provide the stored operator policy information to the PCF (155).

[0050] Additionally, NEF (140) can perform functions such as transmitting or receiving externally events occurring in the 5G system and supported capabilities. For example, NEF (140) can perform functions such as safely supplying AF / AS (170) information to 5GC, converting internal / external information, and storing and redistributing information received from other NFs in UDR.

[0051] The terminal (100) can connect to the NG-RAN (105) and register with the 5G system. For example, the terminal can connect to the NG-RAN and perform a terminal registration procedure with the AMF (110). During the registration procedure, the AMF (110) can determine a network slice available to the terminal (100) connected to the NG-RAN (105) and allocate it to the terminal (100). The terminal (100) can select a network slice and establish a PDU session for communication with the AF / AS (170). One PDU session can include one or more QoS Flows, and each QoS Flow can provide different transmission performances required for each application service by setting different QoS parameters.

[0052] Additionally, the basic functions of the network entities in the following embodiments may refer to the description in Fig. 1a.

[0053] According to the present disclosure, when providing communication services by installing a femto base station in a wireless communication system, a femto system including a femto base station, a local SMF, and / or a local UPF can be configured. The femto system is a system for using 5G communication services in a narrow area, such as a single floor of a house or building, and a communication service provider may not directly install the base station. For example, a consumer (user) can purchase and install a femto system to receive high-quality 5G communication services through the femto system. When providing communication services to a terminal connected to the local data network of the femto system, traffic from the macro data network can be offloaded to the local data network, which can have the effects of traffic distribution and wireless resource conservation.

[0054] In this disclosure, we propose a method for a terminal connected to a wireless network via a femto base station to receive 5G communication services via a local data network.

[0055] According to various embodiments of the present disclosure, when a terminal in a wireless communication system receives a communication service through a femto system including a femto base station, the terminal can use a local data network to offload traffic of a macro data network to the local data network, thereby saving wireless resources of the macro base station.

[0056] In the present disclosure, a macro system or femto system may include an NG-RAN and a 5GC. The NG-RAN may be a base station (e.g., gNB, IAB (Integrated Access and Backhaul), etc.) that supports wireless access technology in a 5G system.

[0057] FIG. 1b is a diagram illustrating an example of the structure of a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0058] Referring to FIG. 1b, the femto system (10a) may include L-SMF, L-UPF, etc. in addition to F-gNB, and the macro system (20) may include AMF, SMF, PCF, UPF, AUSF, UDM, etc. described in the example of FIG. 1a. The macro system (20) in FIG. 1b is an example and may have the same configuration as the example of FIG. 1a.

[0059] Also, referring to FIG. 1b, a security gateway (SeGW) is connected between the femto system (10a) and the macro system (20) to enable secure communication between the femto system (10a) and the macro system (20). At this time, in the case of a PDU Session of a terminal connecting to a local data network through the femto system (10a), L-SMF may be selected as a serving SMF and L-UPF may be selected as a PSA (PDU Session Anchor) UPF to create a PDU Session.

[0060] In the example of Fig. 1b, downlink data transmitted from the macro system (20) to the terminal may be transmitted to the terminal via the femto base station, F-gNB, or Femto NG-RAN via the L-UPF of the femto system (10a). In addition, uplink data transmitted from the terminal to the macro system (20) may be transmitted from the terminal (UE) to the macro system (20) via the femto base station, F-gNB, or Femto NG-RAN of the femto system (10a) via the L-UPF.

[0061] FIG. 1c is a diagram illustrating an example of the structure of a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0062] Referring to FIG. 1c, the femto system (10c) may include L-UPF, etc. in addition to F-gNB, and the macro system (20) may include AMF, SMF, PCF, UPF, AUSF, UDM, etc. described in the example of FIG. 1a. The macro system (20) in FIG. 1b is an example and may have the same configuration as the example of FIG. 1a.

[0063] Also, referring to FIG. 1c, a security gateway (SeGW) is connected between the femto system (10b) and the macro system (20) so that communication between the femto system (10b) and the macro system (20) can be safely performed. At this time, in the case of a PDU Session of a terminal connecting to a local data network through the femto system (10b), an SMF in the macro system (20) is selected as a serving SMF, and an L-UPF of the femto system (10b) is selected as a PSA UPF so that a PDU Session can be created.

[0064] In the example of Fig. 1c, downlink data transmitted from the macro system (20) to the terminal may be transmitted to the terminal via the femto base station or F-gNB or Femto NG-RAN via the L-UPF of the femto system (10b). In addition, uplink data transmitted from the terminal to the macro system (20) may be transmitted from the terminal (UE) to the macro system (20) via the femto base station or F-gNB or Femto NG-RAN of the femto system (10b) via the L-UPF. The example of Fig. 1c is different from the example of Fig. 1b in that the femto system (10a) of Fig. 1b further includes an L-SMF, and when the femto system is used in the examples of Figs. 1b and 1c, the data transmission path for the terminal is the same.

[0065] Although the embodiments of the present disclosure described below are described from the perspective of using a femto system for convenience of explanation, the embodiments of the present disclosure propose a method for efficiently transmitting data traffic of a terminal using at least one of a local data network (femto system) and a macro data network (macro system) in a wireless communication system.

[0066] FIG. 2 is a diagram illustrating a method for providing terminal policy information (UE POLICY) for using a femto system to a terminal in a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0067] Referring to FIG. 2, in step 201, a terminal performs a UE registration procedure with the AMF, and in the meantime, in step 202, the AMF can perform a UE policy association establishment procedure with the PCF. At this time, if the PCF recognizes that the terminal has a terminal capability (UE capability) to update the UE policy, and if the UE policy is updated, such as when the URSP (UE Route Selection Policy) is updated as in step 203, the PCF performs a procedure of transmitting the updated URSP information to the terminal through the AMF and receiving a response from the terminal in steps 204 to 207. In step 204, the PCF transmits the updated URSP information to the AMF through a UE policy container, and in step 205, the AMF transmits a NAS (Non-Access-Stratum) message including the UE policy container to the terminal, and the terminal transmits the result of transmitting the updated URSP information to the PCF as a response through steps 206 and 207. Afterwards, the terminal can select a traffic route, such as establishing a PDU Session using the updated URSP information as in step 208.

[0068] According to one embodiment of the present disclosure, the URSP information may include UE policy information (UE POLICY) for determining whether the terminal will receive a communication service through a femto base station or a macro base station, or may include information indicating whether the terminal will receive a communication service through a local data network of the femto system or a macro data network. The UE policy information (UE POLICY) may be included in a UE policy container transmitted from a PCF to the terminal through an AMF, and the UE policy container may be transmitted to the terminal using an NAS message.

[0069] [Table 1]

[0070]

[0071] The above [Table 1] shows an example of the URSP information including a policy (i.e. terminal policy information) regarding whether the terminal will use the femto system.

[0072] Referring to the above [Table 1], for example, if the connection capability or preferred connection is set to 'femto' or 'local data network' as the Traffic Descriptor, that is, if the connection capability or preferred connection is received as 'femto' or 'local data network' from the application and the terminal wants to receive a communication service from the local data network through the femto base station or femto system for the corresponding traffic, the Route Selection Descriptor can be set to receive the communication service from the local data network through the femto base station or femto system. For example, the S-NSSAI designated for the femto system can be assigned to allow the terminal to select the femto system, or the DNN designated for the femto system can be assigned to allow the terminal to select the femto system, or the 3gpp with femto can be assigned as the Access Type preference to allow the terminal to select 3GPP access via the femto system, or the femto can be assigned as the preferred cell type to allow the terminal to select the femto system, or the femto or local data network can be assigned as the preferred data network type to allow the terminal to select the femto system. The Route Selection Descriptor can include some or all of the examples in [Table 1] to allow the terminal to select the femto base station of the femto system or the local data network of the femto system.

[0073] Meanwhile, when the Access Type preference is assigned as 3gpp access or 3gpp with macro as a Route Selection Descriptor, or when the preferred cell type is assigned as macro, or when the preferred data network type is assigned as macro, the terminal can be made to select a macro data network.

[0074] Or, if the traffic given as the traffic descriptor of the above [Table 1] corresponds to an operating system identifier (OSId) and an operating system application identifier (OSApppId) as an application descriptor, for example, and the terminal wishes to receive a communication service from a local data network through a femto base station or femto system for the traffic, the traffic can be set to be set as a Route Selection Descriptor that can receive a communication service from a local data network through the femto base station or femto system. For example, the terminal may be allowed to select the femto system by assigning an S-NSSAI designated for the femto system, or the terminal may be allowed to select the femto system by assigning a DNN designated for the femto system, or the terminal may be allowed to select 3GPP access via the femto system by assigning 3gpp with femto as the Access Type preference, or the terminal may be allowed to select the femto system by assigning femto as the preferred cell type, or the terminal may be allowed to select the femto system by assigning femto or local data network as the preferred data network type. The Route Selection Descriptor may include some or all of the examples in [Table 1] to allow the terminal to select a femto base station of the femto system or a local data network of the femto system.

[0075] Meanwhile, when the Access Type preference is assigned as 3gpp access or 3gpp with macro as the Route Selection Descriptor, or when the preferred cell type is assigned as macro, or when the preferred data network type is assigned as macro, a macro data network can be selected.

[0076] Meanwhile, in the above [Table 1], a precedence can be assigned to the Route Selection Descriptor so that the Route Selection Descriptor mapped in order of highest precedence can be used. For example, when a terminal receives a request for a PDU Session from an application, the terminal selects the Route Selection Descriptor with the highest precedence mapped among the Route Selection Descriptors corresponding to the corresponding Traffic Descriptor. In other words, when the terminal is not connected to a femto base station, even if the precedence is high, the Route Selection Descriptor that causes the terminal to select a femto base station of the femto system or a local data network of the femto system is not mapped, so the terminal selects a route according to a Route Selection Descriptor with a lower precedence.

[0077] FIG. 3A and FIG. 3B are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) for a terminal connected through a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure.

[0078] Referring to FIGS. 3a and 3b, an embodiment is illustrated in which a terminal receives communication services from a local data network using a PDU session established through a femto system including an F-gNB and an L-UPF.

[0079] Referring to FIG. 3A, when the femto system is first installed, the femto system connects to the macro system as in step 301 to authenticate the femto system and register the network entity(ies) of the femto system with the macro system so that the network entities of the femto system and the network entities of the macro network can be linked to perform operations for providing services. For authentication and security between the femto system and the macro system, a transaction between the femto system and the macro system can be performed through the security GW (SeGW) of the macro network. For example, the F-gNB can be registered so that it can be identified in the AMF of the macro system. Through the registration, the AMF can obtain information such as the address information of the F-gNB, the cell ID of the F-gNB, the Femto ID, or the femto indication indicating that the base station is a femto base station.

[0080] Additionally, the L-UPF of the femto system can register with the NRF of the macro system, so that network entities of the macro system can find the L-UPF of the femto system as needed. For example, as in step 302, the L-UPF can send an NFRegister message to the NRF of the macro system. Through this, the L-UPF can announce that it is a UPF and also register information about the femto system.

[0081] Additionally, according to one embodiment, the NFRegistser message may include at least one of the ID of the femto system to which the L-UPF belongs, the cell ID of the F-gNB, the femto indication indicating that it is a femto system, the dedicated S-NSSAI used for the femto system, or the address information of the L-UPF. The NRF may store the above-described information (e.g., information about the femto system, etc.) in the NF profile so that it can respond when another network entity, such as the SMF, seeks the L-UPF of the femto system in the future.

[0082] After the femto system is registered in the macro network, the terminal performs registration with the communication network through the F-gNB as in step 303.

[0083] After completing network registration and in a situation where URSP information is shared between the terminal and the macro system as in step 304, in a situation where the terminal establishes a PDU session through an application, etc., in step 305, the terminal determines / selects a route based on the URSP information mentioned above, based on an appropriate route selection description such as S-NSSAI, DNN, access type preference, preferred cell type, or preferred data network type, and accordingly, the PDU session establishment request procedure can be initiated.

[0084] In presenting an embodiment of the present disclosure, a situation in which a matching Route is selected to connect to a local data network via a femto system will be described as an example.

[0085] The terminal may transmit a PDU Session establishment request message including an indication that it wants to connect to a local data network, such as a local DN indication, in step 306. Alternatively, when the terminal transmits an MM-NAS message including the PDU Session establishment request message to the AMF, the terminal may transmit an MM-NAS message including an S-NSSAI or DNN created / configured / allocated for the purpose of connecting to a local data network, or including an indication that it wants to connect to a local data network, such as a local DN indication, so that the AMF can determine the intention of the terminal (e.g., whether to use a local data network or a macro data network, etc.) in step 307. Alternatively, the terminal may perform step 306 without including a local DN indication in any message.

[0086] The F-gNB, which has received the AN message from the terminal, may transmit an N2 message including the received MM-NAS message and the N2 parameter to the AMF in step 307. The N2 parameter may include information on the F-gNB to which the terminal is connected. For example, the N2 parameter may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG (Closed Access Group) ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0087] Meanwhile, the AMF that receives the N2 message selects an SMF in the macro system in step 308, and can transmit an Nsmf_PDUSession_CreateSMContext Request message including the PDU Session establishment request message included in the MM-NAS message to the selected SMF in step 309. In addition, if the AMF recognizes from the S-NSSAI or DNN or local DN indication received in step 307 that the MM-NAS message is for establishing a PDU Session to be serviced through a local data network in the femto system, the AMF can include the local DN indication in the Nsmf_PDUSession_CreateSMContext Request message. In addition, if the N2 parameter includes information on the F-gNB to which the terminal is connected, the Nsmf_PDUSession_CreateSMContext Request message may include information on the F-gNB. The information of the above F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0088] The SMF, which receives the Nsmf_PDUSession_CreateSMContext Request message in step 309, can identify that the terminal will use the local data network via the femto system based on the local DN indication included in the message or the local DN indication included in the PDU Session establishment request message. In addition, the SMF can use the SM policy information received from the PCF in steps 310 to 312 to be authenticated for use of the local data network (i.e., the femto system) for the requested S-NSSAI and DNN. At this time, when the SMF requests the PCF for the SM policy association establishment in step 310, the request message may include some or all of the S-NSSAI, the DNN, the local DN indication, or the information of the F-gNB to which the terminal is connected. The information of the above F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0089] Referring to FIG. 3b, in response to a request in step 310, the PCF performs authentication for the PDU Session in step 311, and based on the authentication result, when the PCF transmits the SM policy to the SMF as in step 312, the authentication result for the use of the local data network may be included for the requested S-NSSAI and DNN. For example, the PCF may transmit an authentication confirmation for an authentication request from the SMF, or may directly include a local DN indication to indicate that the local data network can be used. Accordingly, the SMF, which has received the authentication confirmation, may find / select an L-UPF in the femto system to which the terminal is connected as in step 313. Steps 313a and 313b, which will be described below, may be understood as detailed operations of step 313 when selecting an L-UPF via NRF. It should be noted that the embodiments of the present disclosure are not limited to selecting an L-UPF via NRF. That is, the operation of step 313 may include various operations for selecting L-UPF without using NRF, in which case steps 313a and 313b may be omitted.

[0090] At this time, the SMF can transmit an Nnrf_NFDiscovery request message to the NRF as in step 313a to obtain information about the UPF in the femto system. At this time, the Nnrf_NFDiscovery request message can include information about the UPF, which is a network entity that the SMF is trying to find, and the Nnrf_NFDiscovery request message can include not only the S-NSSAI or the DNN, but also the Femto ID obtained through step 309 to indicate the femto system or F-gNB to which the terminal is connected, the cell ID of the F-gNB, or part or all of the Femto indication information. The NRF, which has received the request of step 313a, can provide the SMF with address information about the L-UPF in the femto system to which the terminal is connected in step 313b. The address information of the L-UPF can include at least one of the FQDN (Fully Qualified Domain Name) of the L-UPF or the IP address and port information of the L-UPF. Of course, it is not limited to the above example.

[0091] In step 314, the SMF sets up a user plane through an N4 message with the L-UPF selected in step 313, and in steps 315 to 318, the remaining PDU Session establishment process, such as transmission of a PDU Session establishment accept message, is performed to create a PDU Session through which a terminal can receive communication services through a local DN.

[0092] FIG. 4A and FIG. 4B are diagrams illustrating a method for creating a PDU session based on subscription information of a terminal connected to a network through a femto system according to an embodiment of the present disclosure.

[0093] Referring to FIGS. 4a and 4b, an embodiment is illustrated in which a terminal receives a communication service from a local data network using a PDU session established through a femto system including an F-gNB, an L-SMF, and an L-UPF.

[0094] Referring to FIG. 4A, when a femto system is installed, in step 401, the femto system connects to the macro system to authenticate the femto system, and in step 402, the network entities of the femto system can be registered with the macro system so that the network entities of the femto system and the network entities of the macro system can be linked to perform operations for providing services. In order to authenticate and secure between the femto system and the macro system, a transaction between the femto system and the macro system can be performed through the security GW (SeGW) of the macro network. For example, the F-gNBF can be registered so that it can be identified in the AMF of the macro system. Through the registration, the AMF can obtain information such as the address information of the F-gNB, the cell ID of the F-gNB, the Femto ID, or the femto indication indicating that the base station is a femto base station. In addition, the ID and address information of the L-SMF can be registered with the AMF during the registration process.

[0095] Additionally, the L-SMF of the femto system can register with the NRF of the macro system, and network entities of the macro system can find the L-SMF of the femto system as needed. For example, in step 402, the L-SMF can send an NFRegister message to the NRF of the macro system. Through this, the L-SMF can notify itself that it is the SMF of the femto system and also register information about the femto system.

[0096] Additionally, according to one embodiment, the NFRegister message may include at least one of the ID of the femto system to which the L-SMF belongs, the cell ID of the F-gNB, the femto indication indicating that it is a femto system, the dedicated S-NSSAI used for the femto system, or the address information of the L-SMF. The NRF may store the above-described information (e.g., information about the femto system, etc.) in the NF profile so that it can respond when other network entities, such as the AMF, seek the L-SMF of the femto system in the future.

[0097] After the femto system is registered in the macro network, the terminal can perform registration in the communication network through the F-gNB as in step 403. At this time, the AMF can obtain subscription information from the UDM through the processes of steps 403a and 403b. For example, the subscription information may include a local DN indication that notifies the S-NSSAI or DNN of local data network access through the femto system as SMF selection subscription information or SM subscription information.

[0098] After completing network registration and in a situation where URSP information is shared between the terminal and the macro system as in step 404, in a situation where the terminal establishes a PDU session through an application, etc., in step 405, the terminal determines / selects a route based on an appropriate route selection description such as S-NSSAI, DNN, access type preference, preferred cell type, or preferred data network type according to URSP, and accordingly, the PDU session establishment request procedure can be initiated.

[0099] In presenting an embodiment of the present disclosure, a situation in which a matching Route is selected to connect to a local data network via a femto system will be described as an example.

[0100] When the terminal transmits an MM-NAS message including a PDU Session establishment request message to the AMF in step 406, the terminal may transmit an MM-NAS message including an S-NSSAI or DNN created / configured / allocated for local data network access, or an indication of wanting to access a local data network, such as a local DN indication, so that the AMF can determine the intention of the terminal (e.g., whether to use a local data network or a macro data network). Alternatively, the terminal may perform step 406 without including a local DN indication in any message.

[0101] The F-gNB, which has received the AN message from the terminal, may transmit an N2 message including the received MM-NAS message and the N2 parameter to the AMF in step 407. The N2 parameter may include information about the F-gNB to which the terminal is connected. For example, the N2 parameter may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0102] Meanwhile, the AMF that receives the N2 message selects the SMF in step 408. Steps 408a and 408b, which will be described later, can be understood as detailed operations of step 408 when selecting (L-)SMF via NRF. It should be noted that the embodiment of the present disclosure is not limited to selecting (L-)SMF via NRF. That is, the operation of step 408 may include various operations for selecting (L-)SMF without using NRF, in which case steps 408a and 408b may be omitted.

[0103] At this time, if the AMF recognizes from the S-NSSAI or DNN or local DN indication received in step 407 that the MM-NAS message is attempting to establish a PDU Session to be serviced through a local data network in the femto system, the AMF may select an SMF in the femto system to which the terminal is connected. Alternatively, if the AMF includes a local DN indication in the subscription information received from the UDM in step 403b to enable the S-NSSAI or DNN requested by the terminal to be serviced through a local data network in the femto system, the AMF may select an SMF in the femto system to which the terminal is connected.

[0104] At this time, the AMF can use the information registered by the L-SMF in step 401 or discover and select the L-SMF in the femto system, such as the F-gNB to which the terminal is connected, through the NRF.

[0105] When using NRF, AMF can transmit Nnrf_NFDiscovery request message to NRF as in step 408a to obtain information of SMF in femto system. At this time, Nnrf_NFDiscovery request message can include information about SMF which is a network entity that AMF is trying to find, and said Nnrf_NFDiscovery request message can include part or all information of Femto ID or cell ID of F-gNB or Femto indication obtained through step 407 to indicate femto system or F-gNB to which terminal is connected as well as S-NSSAI or DNN. NRF that receives request of step 408a can provide address information of L-SMF in femto system to which terminal is connected to AMF in step 408b. The address information of L-SMF can include at least one of FQDN of L-SMF or IP address and port information of L-SMF. Of course, it is not limited to the above example.

[0106] Referring to FIG. 4b, the AMF may transmit an Nsmf_PDUSession_CreateSMContext Request message including the PDU Session establishment request message included and transmitted in the MM-NAS message of step 407 to the selected SMF in step 409. In addition, if the N2 parameter of step 407 includes information on the F-gNB to which the terminal is connected, the Nsmf_PDUSession_CreateSMContext Request message may include information on the F-gNB. The information on the F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a Femto base station.

[0107] The L-SMF, which receives the Nsmf_PDUSession_CreateSMContext Request message in step 409, can use the SM policy information received from the PCF through steps 410 to 412 to authenticate the use of the local data network for the requested S-NSSAI and DNN. At this time, when the L-SMF requests the SM policy association establishment in step 410, the request message may include all or part of the S-NSSAI or the DNN or the local DN indication or the information of the F-gNB to which the terminal is connected. The information of the F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a Femto base station.

[0108] Upon request of step 410, PCF performs authentication for PDU Session in step 411 and, based on the authentication result, when PCF transmits SM policy to SMF as in step 412, it may include authentication result for use of local data network for requested S-NSSAI and DNN. For example, PCF may transmit authentication confirmation for authentication request from L-SMF or directly include local DN indication to notify that use of local data network is possible. Accordingly, L-SMF which receives authentication confirmation may find / select L-UPF in femto system to which terminal is connected as in step 413.

[0109] In step 414, the SMF sets up a user plane through an N4 message with the L-UPF selected in step 413, and in steps 415 to 418, the remaining PDU Session establishment process, such as transmission of a PDU Session establishment accept message, is performed to create a PDU Session through which a terminal can receive communication services through a local DN.

[0110] FIG. 5A and FIG. 5B are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) of a terminal connected to a network via a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure. The present embodiment relates to a method for creating a PDU session by replacing an SMF when the local data network or macro data network selected according to the UE policy does not match the network of the selected SMF when the AMF is configured to select an SMF in a macro system according to an operator's policy or an AMF's own policy, or to select an L-SMF in a femto system.

[0111] Referring to FIGS. 5a and 5b, an embodiment is illustrated in which a terminal receives a communication service from a local data network using a PDU session established through a femto system including an F-gNB, an L-SMF, and an L-UPF.

[0112] Referring to FIG. 5A, when a femto system is installed, in step 501, the femto system connects to the macro system to authenticate the femto system and register the network entities of the femto system with the macro system so that the network entities of the femto system and the network entities of the macro system can be linked to perform operations for providing services. For authentication and security between the femto system and the macro system, a transaction between the femto system and the macro system can be performed through the security GW (SeGW) of the macro network. For example, the F-gNBF can be registered so that it can be identified to the AMF of the macro system. Through the registration, the AMF can obtain information such as the address information of the F-gNB, the cell ID of the F-gNB, the Femto ID, or the femto indication indicating that the base station is a femto base station. In addition, the ID and address information of the L-SMF can be registered with the AMF during the registration process.

[0113] Additionally, the L-SMF of the femto system can register with the NRF of the macro system, and network entities of the macro system can find the L-SMF of the femto system as needed. For example, in step 502, the L-SMF can send an NFRegister message to the NRF of the macro system. Through this, the L-SMF can notify itself that it is the SMF of the femto system and also register information about the femto system.

[0114] Additionally, according to one embodiment, the NFRegister message may include at least one of the ID of the femto system to which the L-SMF belongs, the cell ID of the F-gNB, the femto indication indicating that it is a femto system, the dedicated S-NSSAI used for the femto system, or the address information of the L-SMF. The NRF may store the above-described information (e.g., information about the femto system, etc.) in the NF profile so that it can respond when other network entities, such as the AMF, seek the L-SMF of the femto system in the future.

[0115] After the femto system is registered in the macro network, the terminal can perform registration in the communication network through the F-gNB as in step 503. Then, in a situation where URSP information is shared between the terminal and the macro system as in step 504, the terminal establishes a PDU session through an application, etc., and determines / selects a route according to an appropriate route selection description such as S-NSSAI, DNN, access type preference, preferred cell type, or preferred data network type according to the URSP, and can start the PDU session establishment request procedure accordingly.

[0116] In presenting an embodiment of the present disclosure, a situation in which a matching Route is selected to connect to a local data network via a femto system will be described as an example.

[0117] When the terminal transmits an MM-NAS message including a PDU Session establishment request message to the AMF in step 506, the terminal may transmit an MM-NAS message including an S-NSSAI or DNN created / configured / allocated for local data network access, or an indication of wanting to access a local data network, such as a local DN indication, so that the AMF can determine the intention of the terminal (e.g., whether to use a local data network or a macro data network). Alternatively, the terminal may perform step 506 without including a local DN indication in any message.

[0118] The F-gNB, which has received the AN message from the terminal, may transmit an N2 message including the received MM-NAS message and the N2 parameter to the AMF in step 507. The N2 parameter may include information on the F-gNB to which the terminal is connected. For example, the N2 parameter may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0119] Meanwhile, the AMF that receives the N2 message selects the SMF in step 508. Steps 508a and 508b, which will be described later, can be understood as detailed operations of step 508 when selecting (L-)SMF via NRF. It should be noted that the embodiment of the present disclosure is not limited to selecting (L-)SMF via NRF. That is, the operation of step 508 may include various operations for selecting (L-)SMF without using NRF, in which case steps 508a and 508b may be omitted.

[0120] At this time, based on the S-NSSAI or DNN received in step 507, or the operator's policy, or the AMF's own policy, the AMF selects an SMF in the macro system or an SMF in the femto system to which the terminal is connected. Here, the example of selecting an SMF in the macro system was described, but the present disclosure can also be applied to a case where an SMF in the femto system is selected.

[0121] At this time, the above AMF can use NRF as in steps 508a and 508b to find a suitable SMF in the macro system.

[0122] Referring to FIG. 5b, the AMF may transmit an Nsmf_PDUSession_CreateSMContext Request message including a PDU Session establishment request message included in the MM-NAS message to the selected SMF in step 509, and the SMF receiving the message may use the SM policy information received from the PCF in steps 510 to 512 to be authenticated for use of the local data network for the requested S-NSSAI and DNN. At this time, when the SMF of the macro system requests the SM policy association establishment in step 510, the request message may include all or part of the S-NSSAI or the DNN or the local DN indication or the information of the F-gNB to which the terminal is connected. The information of the F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a Femto base station.

[0123] In response to the request of step 510, the PCF performs authentication for the PDU Session in step 511, and based on the authentication result, when the PCF transmits the SM policy to the SMF as in step 512, the PCF may include the authentication result for using the local data network for the requested S-NSSAI and DNN. For example, the PCF may transmit an authentication confirmation for the authentication request from the SMF, or may directly include a local DN indication to indicate that the local data network can be used. Accordingly, the SMF that has received the authentication confirmation must create a PDU session using the local data network according to the received policy as in step 513, but recognizes that the SMF is in the macro system, and notifies the AMF that the selection of the SMF is incorrect (i.e., the selected SMF was incorrectly selected as the SMF of the macro system) as in step 514.

[0124] In step 514, when the SMF sends the Nsmf_PDUSession_CreateSMContext Response to the AMF, the SMF may include reject to indicate that the PDU session establishment request in step 509 was rejected, and an indication that the femto system should be selected as the cause of the rejection or an indication that the local DN should be selected may be included. Accordingly, the AMF proceeds with the process of selecting a new SMF in the femto system, and when using the NRF, the AMF may send the Nnrf_NFDiscovery request message to the NRF in step 508c to obtain information about the SMF in the femto system. At this time, the Nnrf_NFDiscovery request message may include information about the SMF, which is a network entity that the AMF is trying to find, and may include not only the S-NSSAI or DNN, but also the Femto ID obtained through step 507 to indicate the Femto system or F-gNB to which the terminal is connected, or part or all of the cell ID of the F-gNB, or the Femto indication. The NRF, which received the request of step 508c, may transmit the address information of the L-SMF in the Femto system to which the terminal is connected to the AMF in step 508d. The address information of the L-SMF may include the FQDN or IP address and port information of the L-SMF. Of course, it is not limited to the above example.

[0125] Thereafter, the AMF can send an Nsmf_PDUSession_CreateSMContext Request message including the PDU Session establishment request message included in the MM-NAS message to the L-SMF selected by steps 508c and 508d in step 515, and accordingly, the L-SMF can select an L-UPF in step 516, and perform the remaining PDU Session establishment procedures in steps 516 and 517, such as setting up a User plane through an N4 message, to create a PDU Session through which the terminal can receive communication services through the local DN.

[0126] FIGS. 6A and 6B are diagrams illustrating a method for creating a PDU session based on terminal policy information (UE POLICY) for a terminal connected to a network via a femto system in a wireless communication system supporting a femto system according to an embodiment of the present disclosure. The present embodiment relates to a method for creating a PDU session using I-UPF (Intermediate UPF) (not shown) when the local data network or macro data network selected according to the UE policy does not match the network of the selected SMF when the AMF is configured to select an SMF in a macro system according to an operator's policy or an AMF's own policy, or to select an L-SMF in a femto system.

[0127] Referring to FIGS. 6a and 6b, an embodiment is illustrated in which a terminal receives a communication service from a local data network using a PDU session established through a femto system including an F-gNB, an L-SMF, and an L-UPF.

[0128] Referring to FIG. 6A, when a femto system is installed, in step 601, the femto system can access the macro system to authenticate the femto system and register the network entities of the femto system with the macro system so that the network entities of the femto system and the network entities of the macro system can be linked to perform operations for providing services. For authentication and security between the femto system and the macro system, a transaction between the femto system and the macro system can be performed through the security GW (SeGW) of the macro network. For example, the F-gNBF can be registered so that it can be identified to the AMF of the macro system. Through the registration, the AMF can obtain information such as the address information of the F-gNB, the cell ID of the F-gNB, the Femto ID, or the femto indication indicating that the base station is a femto base station. In addition, the ID and address information of the L-SMF can be registered with the AMF during the registration process.

[0129] Additionally, the L-SMF of the femto system can register with the NRF of the macro system, and network entities of the macro system can find the L-SMF of the femto system as needed. For example, in step 602, the L-SMF can send an NFRegister message to the NRF of the macro system. Through this, the L-SMF can notify itself that it is the SMF of the femto system and also register information about the femto system.

[0130] Additionally, according to one embodiment, the NFRegister message in step 602 may include at least one of the ID of the femto system to which the L-SMF belongs, the cell ID of the F-gNB, the femto indication indicating that it is a femto system, the dedicated S-NSSAI used for the femto system, or the address information of the L-SMF. The NRF may store the above-described information (e.g., information about the femto system, etc.) in the NF profile so that it can respond when other network entities, such as the AMF, seek the L-SMF of the femto system in the future.

[0131] Additionally, the L-UPF of the femto system can register with the NRF of the macro system, and network entities of the macro system can find the L-UPF of the femto system as needed. For example, the L-UPF can send an NFRegister message to the NRF of the macro system, as in step 602a. Through this, the L-UPF can notify itself that it is the UPF of the femto system and also register information about the femto system.

[0132] Additionally, according to one embodiment, the NFRegister message in step 602a may include the ID of the femto system to which the L-UPF belongs, the cell ID of the F-gNB, the femto indication indicating that it is a femto system, or the address information of the dedicated S-NSSAI or L-SMF used for the femto system. The NRF may store the above-mentioned information (e.g., information about the femto system, etc.) in the NF profile so that it can respond when other network entities, such as the SMF, seek the L-UPF of the femto system in the future.

[0133] After the femto system is registered in the macro network, the terminal can perform registration in the communication network through the F-gNB as in step 603. Then, in a situation where URSP information is shared between the terminal and the macro system as in step 604, the terminal establishes a PDU session through an application, etc., and determines / selects a route according to an appropriate route selection description such as S-NSSAI, DNN, access type preference, preferred cell type, or preferred data network type according to the URSP, and can start the PDU session establishment request procedure accordingly.

[0134] In presenting an embodiment of the present disclosure, a situation in which a matching Route is selected to connect to a local data network via a femto system will be described as an example.

[0135] When the terminal transmits an MM-NAS message including a PDU Session establishment request message to the AMF in step 606, the terminal transmits an MM-NAS message including an S-NSSAI or DNN created / configured / allocated for local data network access, or an indication of wanting to access a local data network, such as a local DN indication, so that the AMF can determine the intention of the terminal (e.g., whether to use a local data network or a macro data network). Alternatively, the terminal may perform step 606 without including a local DN indication in any message.

[0136] The F-gNB, which has received the AN message from the terminal, may transmit an N2 message including the received MM-NAS message and the N2 parameter to the AMF in step 607. The N2 parameter may include information about the F-gNB to which the terminal is connected. For example, the N2 parameter may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a femto base station.

[0137] Meanwhile, the AMF that receives the N2 message selects the SMF in step 608. Steps 608a and 608b, which will be described later, can be understood as detailed operations of step 608 when selecting (L-)SMF via NRF. It should be noted that the embodiment of the present disclosure is not limited to selecting (L-)SMF via NRF. That is, the operation of step 608 may include various operations for selecting (L-)SMF without using NRF, in which case steps 608a and 608b may be omitted.

[0138] At this time, based on the S-NSSAI or DNN received in step 607, or the operator's policy, or the AMF's own policy, the AMF selects an SMF in the macro system or an SMF in the femto system to which the terminal is connected. Here, the example of selecting an SMF in the macro system was described, but the present disclosure can also be applied to a case where an SMF in the femto system is selected.

[0139] At this time, the above AMF can use NRF as in steps 608a and 608b to find a suitable SMF in the macro system.

[0140] Referring to FIG. 6b, the AMF may transmit an Nsmf_PDUSession_CreateSMContext Request message including a PDU Session establishment request message transmitted in an MM-NAS message to the selected SMF in step 609, and the SMF receiving the message may use the SM policy information received from the PCF in steps 610 to 612 to be authenticated for use of the local data network for the requested S-NSSAI and DNN. At this time, when the SMF of the macro system requests the SM policy association establishment in step 610, the request message may include all or part of the S-NSSAI or the DNN or the local DN indication or the information of the F-gNB to which the terminal is connected. The information of the F-gNB may include all or part of the ID of the femto system to which the F-gNB belongs, the Cell ID of the F-gNB, the CAG ID allowed by the F-gNB, or the Femto indication indicating that it is a Femto base station.

[0141] In response to the request of step 610, the PCF performs authentication for the PDU Session in step 611, and based on the authentication result, when the PCF transmits the SM policy to the SMF as in step 612, the PCF may include the authentication result for using the local data network for the requested S-NSSAI and DNN. For example, the PCF may transmit an authentication confirmation for an authentication request from the SMF, or may directly include a local DN indication to indicate that the local data network can be used. At this time, the PCF may transmit to the SMF, for example, 5 tuples and information about the application ID and characteristics of the application traffic, regarding data that must use the local data network. The 5 tuples may include five pieces of information that are well known as characteristics for filtering traffic: Source IP address, Destination IP address, source port number, destination port number, and protocol ID. That is, by using the L-UPF as the I-UPF that functions as an ULCL (Uplink classifier) ​​to utilize a local data network, it is possible to notify that the terminal can receive communication services through the femto system (i.e., through the local data network) for the specific traffic.

[0142] Accordingly, the SMF that has received the authentication creates a PDU session in step 613 so that the terminal can receive communication services through the local data network through the ULCL function for some data traffic and can receive communication services through the macro data network for some data traffic according to the received policy (SM policy). At this time, a method for filtering data traffic for which the terminal will receive communication services through the local data network can be as in the general UPF, by following the policy (SM policy) received from the PCF, or by using information for processing traffic pre-stored in the SMF to cause the L-UPF to operate as the I-UPF with the ULCL role. To this end, the SMF selects the L-UPF in the femto system and instructs it to perform the ULCL role, and selects the UPF in the macro system. For example, when the SMF discovers the L-UPF in the femto system and the UPF in the macro system through the NRF, in steps 613a and 613b, the SMF discovers and selects the L-UPF in the femto system to which the terminal is connected, and in steps 613c and 613b, the SMF discovers and selects the UPF in the macro system, and in steps 614 and 615, the SMF creates or modifies an N4 session for each selected L-UPF and UPF to establish a data path for servicing data traffic to the terminal, and in step 614, a rule for detecting data for ULCL, such as filtering information, and a rule for forwarding the detected data through the local data network, can be set for the L-UPF so that the local data network is used through the femto system.

[0143] In step 616, the remaining PDU Session establishment procedure is performed to create a PDU Session that can provide communication services to a terminal through a local DN using the I-UPF of the femto system or provide communication services through the UPF of the macro network.

[0144] According to the above-described embodiments of the present disclosure, when a terminal receives communication services through a femto base station (or femto system) in a wireless communication system, the terminal can use either a local data network or a macro data network, and the data traffic can be efficiently controlled to be transmitted and received through which data network. Therefore, according to the present disclosure, data traffic can be offloaded depending on the network conditions of the terminal and the communication service provider, thereby providing the advantage of efficiently utilizing wireless communication resources.

[0145] FIG. 7 is a diagram showing the configuration of a network entity in a wireless communication system according to an embodiment of the present disclosure.

[0146] The network entity of FIG. 7 may be one of the network entities such as UE, AMF, SMF, PCF (or NSSF), NEF, AF, etc. described in the embodiments of FIGS. 1a to 6b.

[0147] As illustrated in FIG. 7, a network entity may include a processor (701), a transceiver (703), and a memory (705). The processor (701), the transceiver (703), and the memory (705) of the network entity may operate according to the communication method of the network entity described above in the embodiments of FIGS. 1A to 6B . However, the components of the network entity are not limited to the examples described above. For example, the network entity may include more or fewer components than the components described above. In addition, the processor (701), the transceiver (703), and the memory (705) may be implemented in the form of a single chip.

[0148] The transceiver (703) is a general term for a receiver of a network entity and a transmitter of the network entity, and can transmit and receive signals with a terminal or another network entity. At this time, the transmitted and received signal may include at least one of control information and data. To this end, the transceiver (703) may include a wired / wireless transceiver and may include various configurations for transmitting and receiving signals. In addition, the transceiver (703) may receive a signal through a predetermined communication interface, output it to the processor (701), and transmit the signal output from the processor (701). In addition, when the network entity of FIG. 7 is a terminal, the transceiver (703) may include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. In addition, the transceiver (703) can receive a communication signal and output it to the processor (701), and transmit the signal output from the processor (701) to a terminal or another network entity through a network. The memory (705) can store programs and data necessary for the operation of the network entity according to at least one of the embodiments of FIGS. 1A to 6B. In addition, the memory (705) can store control information or data included in a signal acquired from the network entity. The memory (705) 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.

[0149] The processor (701) may control a series of processes so that a network entity can operate according to at least one of the embodiments of FIGS. 1A to 6B. The processor (701) may include at least one processor. 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. In the case of software implementation, 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 in an electronic device. The one or more programs include instructions that cause the electronic device to execute the methods according to the embodiments described in the claims or specification of the present disclosure.

[0150] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies. The above 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 area network (WAN), a storage area network (SAN), or a combination thereof. This storage device may be connected to a device performing 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 performing an embodiment of the present disclosure.

[0151] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural form, 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 the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0152] 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. A method performed by AMF (access and mobility management function) in a wireless communication system supporting a femto system, A process of receiving first information related to the femto system and a PDU (protocol data unit) session establishment request message for the terminal from a femto base station connected to the femto system in the femto system; A process of selecting an SMF (session management function) that manages the PDU session of the terminal based on the first information; and A method comprising the step of transmitting a PDU session creation request message to the selected SMF based on the first information.

2. In paragraph 1, The above receiving process is, A method further comprising a step of checking whether the terminal uses a local data network through the femto system based on whether the PDU session establishment request message includes a local data network indication.

3. In paragraph 2, The above-described transmitting process further includes a process of transmitting a PDU session creation request message including the local data network instruction to the SMF when the PDU session establishment request includes the local data network instruction, A process of receiving a PDU session creation response message from the SMF in response to transmission of the PDU session creation request message; and A method further comprising the step of transmitting a PDU session establishment acceptance message accepting use of the local data network to the terminal via the femto base station.

4. In paragraph 1, The above receiving process is, A process for receiving a NAS (non access stratum) message including the first information and the PDU session establishment request message, A method wherein the first information includes a femto indicator indicating the femto base station.

5. In paragraph 1, A method wherein the first information includes at least one of an ID of the femto system to which the femto base station belongs, a cell ID of the femto base station, a CAG (Closed Access Group) ID allowed by the femto base station, and a femto indicator indicating the femto base station.

6. In a method performed by SMF (session management function) in a wireless communication system supporting a femto system, A process of receiving a PDU session creation request message including information related to the femto system from an AMF (access and mobility management function) that has received a PDU (protocol data unit) session establishment request from a femto base station to which a terminal is connected in the femto system; A process of performing an authentication procedure for using the femto system through a PCF (policy control function) that manages policy information; and A method including a process of selecting a user plane function (UPF) for processing data traffic of the terminal in the femto system based on the authentication result and the information related to the femto system.

7. In paragraph 6, A method for confirming that the terminal uses a local data network through the femto system, when the PDU session creation request message includes a local data network indication, by the SMF based on the local data network indication.

8. In paragraph 6, A method in which information related to the femto system includes at least one of an ID of the femto system to which the femto base station belongs, a cell ID of the femto base station, a Closed Access Group (CAG) ID allowed by the femto base station, and a femto indicator indicating the femto base station.

9. In the AMF (access and mobility management function) in a wireless communication system supporting the femto system, Transmitter and receiver; and Through the above transceiver, the terminal in the femto system receives first information related to the femto system from the femto base station connected to the terminal and a PDU (protocol data unit) session establishment request message for the terminal, Based on the above first information, the SMF (session management function) that manages the PDU session of the terminal is selected, An AMF including a processor configured to transmit, through the transceiver, a PDU session creation request message to the selected SMF based on the first information.

10. In paragraph 9, The above processor, An AMF further configured to determine whether the terminal utilizes a local data network via the femto system based on whether the PDU session establishment request message includes a local data network indication.

11. In Article 10, The above processor, If the above PDU session establishment request includes the local data network indication, transmit a PDU session creation request message including the local data network indication to the SMF through the transceiver, In response to the transmission of the above PDU session creation request message, a PDU session creation response message is received from the SMF through the transceiver, An AMF further configured to transmit a PDU session establishment acceptance message, accepting use of the local data network, to the terminal via the femto base station through the transceiver.

12. In paragraph 9, The above processor, configured to receive a NAS (non access stratum) message including the first information and the PDU session establishment request message through the transceiver; The above first information is an AMF including a femto indicator indicating the femto base station.

13. In a wireless communication system supporting the femto system, in the SMF (session management function), Transmitter and receiver; and Through the above transceiver, a PDU (protocol data unit) session creation request message including information related to the femto system is received from an AMF (access and mobility management function) that has received a PDU session establishment request from a femto base station to which a terminal is connected in the femto system, The authentication procedure for using the above femto system is performed through the policy control function (PCF) that manages policy information. An SMF including a processor configured to select a user plane function (UPF) for processing data traffic of the terminal in the femto system based on the authentication result and the information related to the femto system.

14. In paragraph 13, The above processor, If the above PDU session creation request message includes a local data network instruction, An SMF further configured to verify that the terminal utilizes a local data network via the femto system based on the above local data network instructions.

15. In paragraph 13, Information related to the femto system includes an SMF including at least one of an ID of the femto system to which the femto base station belongs, a cell ID of the femto base station, a Closed Access Group (CAG) ID allowed by the femto base station, and a femto indicator indicating the femto base station.

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