Method for enabling SMF to effectively perform redundant transmission by improving the function of NWDAF

Abstract

One disclosure of the specification may provide a method of operating a session management function (SMF) node for managing a protocol data unit (PDU) session. The method may include the step of acquiring analysis information from a network data analysis function (NWDAF) node. The acquired analysis information may include experience analysis information for redundant transmission. The method may include the step of determining, based on the analysis information, a PDU session to be redundantly transmitted through two tunnels during a process related to the PDU session.

Description

Technical Field

[0001] This specification relates to mobile communications. Background Art

[0002] Figure 1 The structure of an evolved mobile communication network is shown.

[0003] The Evolved Packet Core (EPC) may include various elements. Figure 1 A serving gateway (S-GW) 52, a packet data network gateway (PDN GW) 53, a mobility management entity (MME) 51, a serving general packet radio service (GPRS) support node (SGSN), and an enhanced packet data gateway (ePDG) corresponding to some of the various elements are illustrated.

[0004] The S-GW 52 is an element that operates at a boundary point between a radio access network (RAN) and a core network and has a function of maintaining a data path between the eNodeB 22 and the PDN GW 53. In addition, if a terminal (or user equipment (UE)) moves in an area served by the eNodeB 22, the S-GW 52 serves as a local mobility anchor point. That is, for mobility within an E-UTRAN (i.e., an Evolved Universal Mobile Telecommunications System (Evolved UMTS) terrestrial radio access network defined after 3GPP Release 8), packets can be routed through the S-GW 52. In addition, the S-GW 52 can be used as an anchor point for mobility with another 3GPP network (i.e., a RAN defined before 3GPP Release 8, for example, UTRAN or a Global System for Mobile Communications (GSM) / Enhanced Data Rates for Global Evolution (EDGE) Radio Access Network (GERAN).

[0005] The PDN GW (or P-GW) 53 corresponds to an endpoint of a data interface toward a packet data network. The PDN GW 53 may support policy enforcement features, packet filtering, charging support, etc. In addition, the PDN GW (or P-GW) 53 may serve as an anchor point for mobility management with 3GPP networks and non-3GPP networks (e.g., untrusted networks such as interworking wireless local area networks (I-WLANs) or trusted networks such as code division multiple access (CDMA) networks).

[0006] exist Figure 1 In the network configuration of FIG. 5 , the S-GW 52 and the PDN GW 53 have been illustrated as separate gateways, but the two gateways may be implemented in a single gateway configuration option.

[0007] MME 51 is an element for performing signaling and control functions for UE access network connection and for supporting allocation, tracking, paging, roaming, switching, etc. of network resources. MME 51 controls control plane functions related to subscriber and session management. MME 51 manages numerous eNodeBs 22 and performs traditional signaling for selecting a gateway to switch to other 2G / 3G networks. In addition, MME 51 performs functions such as security procedures, terminal-to-network session processing, and idle terminal location management.

[0008] The SGSN handles all packet data such as mobility management and authentication of users for different access 3GPP networks (eg, GPRS networks and UTRAN / GERAN).

[0009] The ePDG serves as a security node for untrusted non-3GPP networks (eg, I-WLAN and Wi-Fi hotspots).

[0010] As reference Figure 1 As described, a terminal (or UE) with IP capability can access an IP service network (eg, IMS) provided by a service provider (ie, operator) via various elements within the EPC based on non-3GPP access as well as based on 3GPP access.

[0011] also, Figure 1 Various reference points (e.g., S1-U and S1-MME) are shown. In the 3GPP system, the conceptual link connecting two functions existing in different functional entities of E-UTRAN and EPC is called a reference point. The following table 1 defines Figure 1 In addition to the reference points shown in the example of Table 1, various reference points may exist according to the network configuration.

[0012] [Table 1]

[0013]

[0014] exist Figure 1 Among the reference points shown, S2a and S2b correspond to non-3GPP interfaces. S2a is a reference point that provides related control and mobility support between trusted non-3GPP access and PDN GW for the user plane. S2b is a reference point that provides related control and mobility support between ePDG and P-GW for the user plane.

[0015] <Next Generation Mobile Communication Network>

[0016] With the success of Long Term Evolution (LTE) / LTE-Advanced (LTE-A), the 4th generation mobile communications, there has been more interest in the next generation, ie, the 5th generation (also known as 5G), mobile communications and accordingly, extensive research and development is being conducted.

[0017] 5G mobile communications defined in the International Telecommunication Union (ITU) provide data transfer rates of up to 20Gbps and a perceptible transfer rate of at least 100Mbps anytime, anywhere. It is officially called "IMT-2020".

[0018] The fifth generation of mobile communications supports multiple parameter sets (and / or multiple subcarrier spacing (SCS)) to support various 5G services. For example, if the SCS is 15kHz, a wide area can be supported in the traditional cellular band, and if the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidth can be supported. If the SCS is 60kHz or higher, a bandwidth greater than 24.25GHz can be supported to overcome phase noise.

[0019] The NR band is defined as two types of frequency ranges, FR1, FR2. FR1 is 410MHz-7125MHz, and FR2 is 24250MHz-52600MHz, which means millimeter wave (mmW).

[0020] For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean “a range below 6 GHz”. FR2 may mean “a range above 6 GHz” and may be referred to as millimeter wave (mmW).

[0021] [Table 2]

[0022] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz-6000MHz 15,30,60kHz FR2 24250MHz-52600MHz 60,120,240kHz

[0023] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a frequency band from 410 MHz to 7125 MHz, as shown in Table 3 below. That is, FR1 may include a frequency band above 6 GHz (or, 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or, 5850, 5900, 5925 MHz, etc.) included in FR1 may include an unlicensed frequency band. The unlicensed frequency band can be used for various purposes, for example, for communication of vehicles (e.g., autonomous driving).

[0024] [Table 3]

[0025] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15,30,60kHz FR2 24250MHz-52600MHz 60,120,240kHz

[0026] The ITU has proposed three usage scenarios such as enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low-latency communications (URLLC).

[0027] First, URLLC involves usage scenarios that require high reliability and low latency. For example, services such as autonomous driving, factory automation, and augmented reality require high reliability and low latency (e.g., latency less than or equal to 1ms). Currently, the latency statistics for 4G (LTE) are 21-43ms (best 10%) and 33-75ms (median). This is not enough to support services that require latency less than or equal to 1ms.

[0028] Next, eMBB use cases involve use cases that require mobile ultra-wideband.

[0029] The core network designed for existing LTE / LTE-A seems to be difficult to adapt to ultra-wideband high-speed services.

[0030] Therefore, there is an urgent need to redesign the core network of 5G mobile communications.

[0031] Figure 2 It is a structural diagram of the next generation mobile communication network.

[0032] The 5G core (5GC) may include various components (part of which may be Figure 2 ), which includes an access and mobility management function (AMF) 41, a session management function (SMF) 42, a policy control function (PCF) 43, a user plane function (UPF) 44, an application function (AF) 45, a unified data management (UDM) 46 and a non-3GPP interworking function (N3IWF) 49, which correspond to some of the components therein.

[0033] The UE 10 is connected to the data network through the UPF 44 via the Next Generation Radio Access Network (NG-RAN) (i.e., gNB or base station).

[0034] The UE 10 may be provided with data services over an untrusted non-3GPP access, such as a wireless local area network (WLAN). In order to connect the non-3GPP access to the core network, a N3IWF 49 may be deployed.

[0035] Figure 3 is an example diagram illustrating an expected structure of the next generation mobile communication in terms of nodes.

[0036] Reference Figure 3 , the UE is connected to the data network (DN) through NG-RAN.

[0037] The control plane function (CPF) node shown performs all or part of the functions of the mobility management entity (MME) of 4G mobile communication and all or part of the control plane functions of the serving gateway (S-GW) and PDN gateway (P-GW) of 4G mobile communication. The CPF node includes an access and mobility management function (AMF) and a session management function (SMF).

[0038] The user plane function (UPF) node shown is a gateway through which user data is sent / received. The UPF node can perform all or part of the user plane functions of the S-GW or P-GW of 4G mobile communication.

[0039] The Policy Control Function (PCF) shown is the node that controls the provider's policy.

[0040] The shown Application Function (AF) is a server for providing several services to the UE.

[0041] The Unified Data Management (UDM) shown is a server type that manages subscriber information, such as a Home Subscriber Server (HSS) of 4G mobile communications. The UDM stores subscriber information in a Unified Data Repository (UDR) and manages it.

[0042] The Authentication Server Function (AUSF) shown authenticates and manages the UE.

[0043] The Network Slice Selection Function (NSSF) shown is a node for network slicing as described below.

[0044] exist Figure 3 In , the UE can use multiple protocol data unit (PDU) sessions to access two data networks simultaneously.

[0045] Figure 4 is an example diagram illustrating an architecture for supporting simultaneous access to two data networks.

[0046] Figure 4 This paper illustrates an architecture that allows a UE to access two data networks simultaneously using one PDU session.

[0047] Figure 3 and Figure 4 The reference points shown are as follows.

[0048] N1 is the reference point between UE and AMF.

[0049] N2 is the reference point between (R)AN and AMF.

[0050] N3 is the reference point between (R)AN and UPF.

[0051] N4 is the reference point between SMF and UPF.

[0052] N5 is the reference point between PCF and AF.

[0053] N6 is the reference point between UPF and DN.

[0054] N7 is the reference point between SMF and PCF.

[0055] N8 is the reference point between UDM and AMF.

[0056] N9 is the reference point between UPFs.

[0057] N10 is the reference point between UDM and SMF.

[0058] N11 is the reference point between AMF and SMF.

[0059] N12 is the reference point between AMF and AUSF.

[0060] N13 is the reference point between UDM and AUSF.

[0061] N14 is the reference point between AMFs.

[0062] N15 is the reference point between PCF and AMF.

[0063] N16 is the reference point between SMFs.

[0064] N22 is the reference point between AMF and NSSF.

[0065] Figure 5 is another example diagram showing the structure of the radio interface protocol between UE and gNB.

[0066] The radio interface protocol is based on the 3GPP radio access network standard. The radio interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and is vertically divided into a user plane for transmitting data information and a control plane for transmitting control signals.

[0067] Based on the lower three layers of the Open Systems Interconnection (OSI) reference model, which is widely known in communication systems, the protocol layer can be divided into L1 (layer 1), L2 (layer 2), and L3 (layer 3).

[0068] Hereinafter, each layer of the radio protocol will be described.

[0069] The first layer, the physical layer, provides information transfer services using physical channels. The physical layer is connected to the upper medium access control layer through a transmission channel, and data between the medium access control layer and the physical layer is transmitted through the transmission channel. In addition, data is transmitted between different physical layers (i.e., between the physical layer on the sending side and the physical layer on the receiving side) through the physical channel.

[0070] The second layer includes a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer.

[0071] The third layer includes a radio resource control (hereinafter referred to as RRC) layer. The RRC layer is defined only in the control plane and is responsible for controlling logical channels, transport channels, and physical channels related to the configuration, reconfiguration, and release of radio bearers. In this case, RB refers to a service provided by the second layer for data transmission between the UE and the E-UTRAN.

[0072] The non-access stratum (NAS) layer performs functions such as connection management (session management) and mobility management.

[0073] The NAS layer is divided into a NAS entity for mobility management (MM) and a NAS entity for session management (SM).

[0074] 1) The NAS entity for MM generally provides the following functions.

[0075] The NAS processes related to AMF include the following.

[0076] -Registration management and access management process. AMF supports the following functions.

[0077] -Secure NAS signaling connection between UE and AMF (integrity protection, encryption)

[0078] 2) The NAS entity for SM performs session management between UE and SMF.

[0079] The NAS-SM layer of the UE and SMF handles (i.e., generates and processes) SM signaling messages. The content of the SM signaling messages is not interpreted by the AMF.

[0080] - In case of SM signaling transmission

[0081] - The NAS entity for MM creates a NAS-MM message which derives how and where to deliver the SM signalling message through a security header indicating the NAS transport of SM signalling and additional information about the received NAS-MM.

[0082] - Upon receiving SM signaling, the NAS entity for SM performs an integrity check of the NAS-MM message, analyzes the additional information, and derives the method and location for deriving the SM signaling message.

[0083] In addition, Figure 5 In the wireless communication network, the RRC layer, RLC layer, MAC layer and PHY layer located below the NAS layer are collectively referred to as the access layer (AS).

[0084] The network system (ie, 5GC) for the next generation mobile communication (ie, 5G) also supports non-3GPP access. An example of non-3GPP access is typically WLAN access. WLAN access can include both trusted WLAN and untrusted WLAN.

[0085] In the system for 5G, AMF performs registration management (RM) and connection management (CM) for 3GPP access as well as non-3GPP access.

[0086] In the next generation (ie, fifth generation) of mobile communications, it is considered to provide a local service (or a dedicated service for each geographical area). In the next generation of mobile communications, such a local service is called LADN.

[0087] In addition, among network nodes, the network data analysis function (NWDAF) can collect UE mobility related information and generate UE mobility statistics or predictions through data analysis.

[0088] Furthermore, redundant transmission is being discussed for URLCC in the next generation (ie, fifth generation) mobile communications.

[0089] However, for redundant transmission, research on functional extension of NWDAF is needed, but there are difficulties that have not been actively promoted yet. Summary of the invention

[0090] Technical Purpose

[0091] Therefore, one object of this specification is to propose a method for solving the above-mentioned problems.

[0092] Technical Solution

[0093] To solve the above problems, the disclosure of the present specification provides a method for operating a session management function (SMF) node for managing a protocol data unit (PDU) session. The method may include obtaining analysis information from a network data analysis function (NWDAF) node. The obtained analysis information may include experience analysis information about redundant transmission. The method may include, based on the analysis information, determining that the PDU session is redundantly transmitted through two tunnels during a process related to the PDU session.

[0094] In order to solve the above problems, the disclosure of this specification may provide a chipset installed on a session management function (SMF) node. The chipset may include: at least one processor; and at least one memory for storing instructions and operably electrically connected to the at least one processor. The instructions may perform operations including the following based on being executed by at least one processor: obtaining analysis information from a network data analysis function (NWDAF) node. The obtained analysis information may include experience analysis information about redundant transmission. The operation may include, based on the analysis information, determining that a PDU session is redundantly transmitted through two tunnels during a process related to the PDU session.

[0095] In order to solve the above problems, the disclosure of this specification may provide an apparatus for a session management function (SMF) node. The device may include: a transceiver; at least one processor; and at least one memory for storing instructions and operably electrically connected to at least one processor. The instructions may perform operations including the following based on being executed by at least one processor: obtaining analysis information from a network data analysis function (NWDAF) node. The obtained analysis information may include experience analysis information about redundant transmission. The operation may include, based on the analysis information, determining that a PDU session is redundantly transmitted through two tunnels during a process related to the PDU session.

[0096] In order to solve the above problems, the disclosure of this specification may provide a non-volatile computer-readable storage medium having instructions recorded thereon. The instructions, when executed by one or more processors installed on a session management function (SMF) node, may cause one or more processors to perform operations. The operations may include obtaining analysis information from a network data analysis function (NWDAF) node. The obtained analysis information may include experience analysis information about redundant transmission. The operations may include, based on the analysis information, determining that a PDU session is redundantly transmitted through two tunnels during a process related to the PDU session.

[0097] Technical Effects

[0098] According to the disclosure of this specification, the problems of the related art can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 The structure of an evolved mobile communication network is shown.

[0100] Figure 2 It is a structural diagram of the next generation mobile communication network.

[0101] Figure 3 is an example diagram illustrating the expected structure of the next generation mobile communication in terms of nodes.

[0102] Figure 4 is an example diagram illustrating an architecture for supporting simultaneous access to two data networks.

[0103] Figure 5 is another example diagram showing the structure of the radio interface protocol between UE and gNB.

[0104] Figure 6a is an example diagram illustrating an example of an architecture for implementing the concept of network slicing.

[0105] Figure 6b is an example diagram illustrating another example of an architecture for implementing the concept of network slicing.

[0106] Figure 7a and Figure 7b is a signal flow diagram illustrating an exemplary registration process.

[0107] Figure 8a and Figure 8b is a signal flow diagram illustrating an exemplary PDU session establishment process.

[0108] Figure 9a and Figure 9b The modification process of the PDU session is shown.

[0109] Fig.10a shows an example of an architecture for redundant transmission, and Fig.10b Another example of an architecture for redundant transmission is shown.

[0110] Fig.11 is an exemplary diagram illustrating a signal flow for the operation of NWDAF.

[0111] Fig.12 is a signal flow diagram illustrating an example of providing analysis to NF.

[0112] Fig.13 is an example diagram illustrating an Xn-based NG-RAN inter-handover procedure without user plane reallocation.

[0113] Fig.14a and Fig.14b is an example diagram illustrating the Xn-based NG-RAN inter-handover procedure when an intermediate UPF exists.

[0114] Fig.15 is an example diagram illustrating Xn-based inter-NG-RAN handover when the intermediate UPF is reallocated.

[0115] Fig.16a and Fig.16b This is an example diagram illustrating the N2-based handover process between NG-RAN nodes in an environment without an Xn interface.

[0116] Figures 17a to 17c This is an example diagram illustrating the N2-based handover process between NG-RAN nodes in an environment without an Xn interface.

[0117] Fig.18 A block diagram of a processor in which the disclosed contents of this specification are implemented is shown.

[0118] Fig.19 A wireless communication system according to an embodiment is illustrated.

[0119] Fig. 20 A block diagram of a network node according to an embodiment is illustrated.

[0120] Fig.21 is a block diagram illustrating a configuration of a UE according to an embodiment.

[0121] Fig. 22 A detailed example Fig.19 A detailed block diagram of the transceiver of the first device shown in FIG. 1 or the transceiver of the device shown in FIG. 17 .

[0122] Fig.23 A communication system 1 to which the disclosure of this specification is applied is exemplified. DETAILED DESCRIPTION

[0123] The technical terms used in this article are only used to describe specific embodiments, and should not be understood as limiting the present disclosure. In addition, unless otherwise defined, the technical terms used in this article should be interpreted as having the meaning commonly understood by those skilled in the art, rather than being too broad or too narrow. In addition, the technical terms used in this article that are determined not to accurately express the spirit of the present disclosure should be replaced by some technical terms that can be accurately understood by those skilled in the art or understood according to these technical terms. In addition, the general terms used in this article should be interpreted in the context defined in the dictionary, rather than being interpreted in an overly narrow manner.

[0124] Unless the meaning of the singular is indeed different from the meaning of the plural in the context, the expressions in the singular in the specification also include the meaning of the plural. In the following description, the term "includes" or "has" may indicate the presence of the features, quantities, steps, operations, components, parts or combinations thereof described in the specification, and may not exclude the presence or addition of another feature, another quantity, another step, another operation, another component, another part or combinations thereof.

[0125] The terms "first" and "second" are used for the purpose of describing various components, and the components are not limited to the terms "first" and "second". The terms "first" and "second" are only used to distinguish one component from another component. For example, a first component may be named a second component without departing from the scope of the present disclosure.

[0126] It should be understood that when an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it can be directly connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers.

[0127] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. In describing the present invention, for ease of understanding, the same reference numerals are used in all drawings to represent the same components, and repeated descriptions of the same components will be omitted. Detailed descriptions of known technologies that are determined to make the subject matter of the present disclosure unclear will be omitted. The accompanying drawings are provided only to make the spirit of the present disclosure easy to understand and should not be intended to limit the present disclosure. It should be understood that the spirit of the present disclosure can be extended to modifications, replacements or equivalents thereof in addition to what is shown in the accompanying drawings.

[0128] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, "A or B" in the present disclosure may be interpreted as "A and / or B". For example, "A, B, or C" in the present disclosure may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0129] In the present disclosure, a slash ( / ) or a comma (,) may represent "and / or". For example, "A / B" may represent "A and / or B". Thus, "A / B" may represent "only A", "only B", or "both A and B". For example, "A, B, C" may represent "A, B, or C".

[0130] In the present disclosure, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, the expression "at least one of A or B" or "at least one of A and / or B" in the present disclosure may be interpreted as being the same as "at least one of A and B".

[0131] Furthermore, in the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” Furthermore, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0132] In addition, the brackets used in the present disclosure may represent "for example". In detail, when shown as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, the "control information" in the present disclosure is not limited to "PDCCH", and "PDCCH" may be proposed as an example of "control information". In addition, even when shown as "control information (ie, PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0133] Technical features described individually in one drawing in the present disclosure may be implemented individually or simultaneously.

[0134] In the drawings, a user equipment (UE) is illustrated by way of example, but the UE shown may also be referred to by terms such as UE 100 (terminal), mobile equipment (ME), etc. In addition, the UE may be a portable device such as a notebook computer, a mobile phone, a PDA, a smart phone, or a multimedia device, or may be a non-portable device such as a PC or a vehicle-mounted device.

[0135] <Network Slicing>

[0136] Hereinafter, network slicing to be introduced in the next generation mobile communication will be described.

[0137] The next generation of mobile communications introduces the concept of network slicing to provide various services through one network. Here, a network slice is a combination of network nodes with the functions required to provide a specific service. The network nodes that constitute a slice instance can be hardware independent nodes or logical independent nodes.

[0138] Each slice instance can consist of a combination of all nodes required to configure the entire network. In this case, one slice instance can serve a UE alone.

[0139] Alternatively, the slice instance may be composed of a combination of some nodes among the nodes constituting the network. In this case, the slice instance may not provide services to the UE alone, but may provide services to the UE in association with other existing network nodes. In addition, multiple slice instances may provide services to the UE in association with each other.

[0140] The difference between a slice instance and a dedicated core network is that the entire network node including the core network (CN) node and the RAN can be separated. In addition, the difference between a slice instance and a dedicated core network is that the network node can be simply logically separated.

[0141] Figure 6a is an example diagram illustrating an example of an architecture for implementing the concept of network slicing.

[0142] As reference Figure 6a As can be seen, the core network (CN) can be divided into several slice instances. Each slice instance can include one or more of the CP functional nodes and the UP functional nodes.

[0143] Each UE can use a network slice instance suitable for its own service through the RAN.

[0144] and Figure 6a Instead, each slice instance can share one or more CP function nodes and UP function nodes with another slice instance. Figure 6b Description is as follows.

[0145] Figure 6b is an example diagram illustrating another example of an architecture for implementing the concept of network slicing.

[0146] Reference Figure 6b , multiple UP functional nodes are clustered, and similarly, multiple CP functional nodes are also clustered.

[0147] In addition, refer to Figure 6b , a slice instance #1 (or referred to as instance #1) in the core network includes a first cluster of UP function nodes. In addition, slice instance #1 shares a CP function node cluster with slice instance #2 (or referred to as instance #2). Slice instance #2 includes a second cluster of UP function nodes.

[0148] The NSSF shown selects a slice (or instance) that can accommodate the UE's service.

[0149] The UE shown can use service #1 through slice instance #1 selected by NSSF, and can use service #2 through slice instance #2 selected by NSSF.

[0150] <Registration Process>

[0151] In order to allow mobility tracking and data reception, and to receive services, the UE needs to obtain authorization. To this end, the UE should register with the network. The registration procedure is performed when the UE needs to perform an initial registration to the 5G system. Additionally, the registration procedure is performed when the UE performs a periodic registration update, when the UE relocates to a new tracking area (TA) in an idle state, and when the UE needs to perform a periodic registration renewal.

[0152] During the initial registration process, the UE ID may be obtained from the UE. The AMF may forward (or transfer) the PEI (IMEISV) to the UDM, SMF, and PCF.

[0153] Figure 7a and Figure 7b is a signal flow diagram illustrating an exemplary registration process.

[0154] 1) The UE may send an AN message to the RAN. The AN message may include AN parameters and a registration request message. The registration request message may include information such as registration type, subscriber permanent ID or temporary user ID, security parameters, network slice selection assistance information (NSSAI), UE's 5G capabilities, protocol data unit (PDU) session status, etc.

[0155] In the case of 5G RAN, the AN parameters may include the Subscription Permanent Identifier (SUPI) or Temporary User ID, the selected network, and the NSSAI.

[0156] The registration type may indicate whether the registration is an "initial registration" (i.e., the UE is in a non-registered state), a "mobility registration update" (i.e., the UE is in a registered state and the registration procedure is initiated by mobility), or a "periodic registration update" (i.e., the UE is in a registered state and the registration procedure is initiated due to expiration of a periodic update timer). In the case where a temporary user ID is included, the temporary user ID indicates the last serving AMF. In the case where the UE has registered in a PLMN other than the PLMN of the 3GPP access through a non-3GPP access, the UE may not provide the UE temporary ID allocated by the AMF during the registration procedure through the non-3GPP access.

[0157] Security parameters can be used for authentication and integrity protection.

[0158] The PDU session status indicates the available (and previously configured) PDU sessions in the UE.

[0159] 2) In case of including SUPI or in case the Temporary User ID does not indicate a valid AMF, the RAN may select an AMF based on the (R)AT and NSSAI.

[0160] In the event that the (R)AN cannot select an appropriate AMF, any AMF is selected according to the local policy, and the registration request is forwarded (or transmitted) by using the selected AMF. If the selected AMF cannot provide service to the UE, the selected AMF may select another AMF that is more suitable for the UE.

[0161] 3) RAN sends an N2 message to the new AMF. The N2 message includes N2 parameters and a registration request. The registration request may include registration type, subscriber permanent identifier or temporary user ID, security parameters, NSSAI, MICO mode default settings (or configuration), etc.

[0162] When using 5G-RAN, the N2 parameters include location information related to the cell where the UE resides, the cell identifier and the RAT type.

[0163] If the registration type indicated by the UE is a periodic registration update, steps 4 to 17, which will be described in detail later, may not be performed.

[0164] 4) The newly selected AMF may send an information request message to the previous AMF.

[0165] In case the temporary user ID of the UE is included in the Registration Request message, and in case the serving AMF is changed after the last registration, the new AMF may include an Information Request message including Complete Registration Request information for requesting the SUPI and MM context of the UE from the previous (or old) AMF.

[0166] 5) The previous (or old) AMF sends an information response message to the newly selected AMF. The information response message may include SUPI, MM context and SMF information.

[0167] More specifically, the previous (or old) AMF sends an Information Response message including the SUPI and MM context of the UE.

[0168] -In the case where information about an active PDU session is included in a previous (or old) AMF, SMF information including SMF ID and PDU session ID may be included in an information response message of the previous (or old) AMF.

[0169] 6) In case the SUPI is not provided by the UE or in case the SUPI is not searched from the previous (or old) AMF, the new AMF sends an Identity Request message to the UE.

[0170] 7) The UE sends an Identity Response message including the SUPI to the new AMF.

[0171] 8) AMF may determine the trigger for executing AUSF. In this case, AMF may select AUSF based on SUPI.

[0172] 9)AUSF can initiate UE authentication and NAS security functions.

[0173] 10) The new AMF may send an Information Response message to the previous (or old) AMF.

[0174] If the AMF changes, the new AMF may send an Information Response message in order to verify the forwarding of the UE MM context.

[0175] - If the authentication / security procedure fails, the registration is rejected and the new AMF may send a rejection message to the previous (or old) AMF.

[0176] 11) The new AMF may send an Identity Request message to the UE.

[0177] In case the PEI is not provided by the UE, or in case the PEI is not searched from the previous (or old) AMF, an Identity Request message may be sent in order to allow the AMF to search for the PEI.

[0178] 12) The new AMF checks the ME identifier.

[0179] 13) If step 14, which will be described later, is performed, the new AMF selects the UDM based on the SUPI.

[0180] 14) If the AMF is modified after the final registration, the new AMF initiates the Update Location procedure if the UE's valid subscription context does not exist in the AMF, or if the UE provides a SUPI where the AMF does not refer to a valid context. Alternatively, the Update Location procedure may be initiated even in case the UDM initiated Cancel Location for the previous AMF. The previous (or old) AMF discards the MM context and notifies all possible SMFs, and the new AMF generates the MM context of the UE after obtaining AM related subscription data from the UDM.

[0181] In case of network slicing, the AMF obtains the allowed NSSAI based on the requested NSSAI and UE subscription and local policy. In case the AMF is not suitable to support the allowed NSSAI, the registration request is rerouted.

[0182] 15) The new AMF may select the PCF based on the SUPI.

[0183] 16) The new AMF sends a UE context establishment request message to the PCF. The AMF can request the PCF for the UE's operator policy.

[0184] 17) PCF sends a UE context establishment confirmation message to the new AMF.

[0185] 18) The new AMF sends an N11 request message to the SMF.

[0186] More specifically, when the AMF changes, the new AMF notifies each SMF of the new AMF that provides services to the UE. The AMF authenticates the PDU session status from the UE by using the available SMF information. In the case of an AMF change, available SMF information may be received from the previous (or old) AMF. The new AMF may send a request to the SMF to release (or cancel) network resources associated with a PDU session that is not activated in the UE.

[0187] 19) The new AMF sends an N11 response message to SMF.

[0188] 20) The previous (or old) AMF sends a UE context termination request message to the PCF.

[0189] In the case where a previous (or old) AMF has previously requested the UE context to be configured in the PCF, the previous (or old) AMF may delete the UE context from the PCF.

[0190] 21) The PCF may send a UE context termination request message to the previous (or old) AMF.

[0191] 22) The new AMF sends a registration acceptance message to the UE. The registration acceptance message may include a temporary user ID, a registration area, mobility restrictions, PDU session status, NSSAI, a periodic registration update timer, and an allowed MICO mode.

[0192] The registration acceptance message may include information about the allowed NSSAI and the mapped NSSAI. Information about the allowed NSSAI information for the access type of the UE may be included in the N2 message containing the registration acceptance message. Information about the mapped NSSAI is information for mapping each S-NSSAI in the allowed NSSAI to the S-NSSAI of the NSSAI set for the HPLMN.

[0193] In the case where the AMF allocates a new temporary user ID, the temporary user ID may also be included in the registration acceptance message. In the case where mobility restrictions are applied to the UE, information indicating the mobility restrictions may additionally be included in the registration acceptance message. The AMF may include information indicating the PDU session status of the UE in the registration acceptance message. The UE may remove any internal resources related to PDU sessions that are not marked as active from the received PDU session status. If PDU session status information is included in the registration request, the AMF may include information indicating the PDU session status to the UE in the registration acceptance message.

[0194] 23) The UE sends a registration completion message to the new AMF.

[0195] <PDU Session Establishment Procedure>

[0196] For the PDU session establishment procedure, as described below, there may be two different types of PDU session establishment procedures.

[0197] - The PDU session establishment procedure initiated by the UE.

[0198] - The PDU session establishment procedure initiated by the network. For this, the network may send a device trigger message to the UE's application (or applications).

[0199] Figure 8a and Figure 8b are signal flow diagrams illustrating exemplary PDU session establishment procedures.

[0200] Figure 8a and Figure 8b The process shown assumes that the UE has Figure 6a and Figure 6b The registration process shown registers with AMF. Therefore, it is assumed that AMF has obtained the user subscription data from UDM.

[0201] 1) The UE sends a NAS message to the AMF. The message may include single network slice selection auxiliary information (S-NSSAI), DNN, PDU session ID, request type, N1 SM information, etc.

[0202] Specifically, the UE includes an S-NSSAI from the allowed NSSAI for the current access type. If information about the mapped NSSAI has been provided to the UE, the UE may provide both an S-NSSAI based on the allowed NSSAI and a corresponding S-NSSAI based on the information about the mapped NSSAI. Here, the information about the mapped NSSAI is information about mapping each S-NSSAI in the allowed NSSAI to an S-NSSAI in the NSSAI set for the HPLMN.

[0203] More specifically, the UE may extract and store Figure 5 The allowed NSSAI and information about the mapped NSSAI are included in the registration acceptance message received from the network (i.e., AMF) during the registration process shown. Therefore, the UE can send by including an S-NSSAI based on the allowed NSSAI and a corresponding S-NSSAI based on the information about the mapped NSSAI in the PDU session establishment request message.

[0204] To establish a new PDU session, the UE may generate a new PDU session ID.

[0205] The PDU session establishment procedure initiated by the UE may be started by sending a NAS message with a PDU session establishment request message included in the N1 SM information. The PDU session establishment request message may include a request type, an SSC mode, and protocol configuration options.

[0206] In the case where the PDU session establishment is for configuring a new PDU session, the request type indicates "initial access". However, in the case where there is an existing PDU session between the 3GPP access and the non-3GPP access, the request type may indicate "existing PDU session".

[0207] The NAS message sent by the UE is encapsulated by the AN in an N2 message. The N2 message is sent to the AMF and may include user location information and access technology type information.

[0208] -N1 SM information may include a SM PDU DN request container including information about PDU session authentication performed by an external DN.

[0209] 2) In case the Request Type indicates "Initial Request", and in case the PDU Session ID is not already in use for an existing PDU Session for the UE, the AMF may determine that the message corresponds to a request for a new PDU Session.

[0210] If the NAS message does not include S-NSSAI, the AMF may determine the default S-NSSAI for the requested PDU Session based on the UE subscription. The AMF may correlate the PDU Session ID with the ID of the SMF and may store the PDU Session ID.

[0211] AMF can select SMF.

[0212] 3)AMF can send a Nsmf_PDUSession_CreateSMContext request message or a Nsmf_PDUSession_UpdateSMContext request message to the selected SMF.

[0213] The Nsmf_PDUSession_CreateSMContext request message may include SUPI, DNN, S-NSSAI, PDU session ID, AMF ID, request type, PCF ID, priority access, N1 SM container, user location information, access type, PEI, GPSI, UE presence in LADN service area, subscription for PDU session status notification, DNN selection mode, and tracking requirements. The SM container may include the PDU session establishment request message.

[0214] The Nsmf_PDUSession_UpdateSMContext request message may include SUPI, DNN, S-NSSAI, SM context ID, AMF ID, request type, N1 SM container, user location information, access type, RAT type, and PEI. The N1 SM container may include a PDU session establishment request message.

[0215] The AMF ID is used to identify the AMF serving the UE. The N1 SM information may include a PDU session establishment request message received from the UE.

[0216] 4) SMF sends a subscriber data request message to UDM. The subscriber data request message may include the subscriber permanent ID and DNN. UDM may send a subscription data response message to SMF.

[0217] In the above step 3, when the request type indicates "existing PDU session", the SMF determines that the corresponding request is caused by switching between 3GPP access and non-3GPP access. The SMF can identify the existing PDU session based on the PDU session ID.

[0218] If the SMF has not searched for the SN-related subscription data of the UE associated with the DNN, the SMF can request the subscription data.

[0219] The subscription data may include the authenticated request type, the authenticated SSC mode, and information about the default QoS profile.

[0220] The SMF may verify that the UE request complies with the user subscription and local policy. Alternatively, the SMF may reject the UE request via NAS SM signaling (including the relevant SM rejection cause), which is forwarded (or transmitted) by the AMF, and then the SMF may notify the AMF that this should be considered as the release of the PDU Session ID.

[0221] 5)SMF sends a Nsmf_PDUSession_CreateSMContext response message or a Nsmf_PDUSession_UpdateSMContext response message to AMF.

[0222] The Nsmf_PDUSession_CreateSMContext response message may include a cause, a SM context ID, or an N1 SM container. The N1 SM container may include a PDU session reject.

[0223] In the above step 3, when SMF receives the Nsmf_PDUSession_CreateSMContext request message and SMF can process the PDU session establishment request message, SMF creates an SM context and the SM context ID is delivered to AMF.

[0224] 6) Secondary authentication / authorization is optionally performed.

[0225] 7a) If a dynamic PCC is used for the PDU session, the SMF selects the PCF.

[0226] 7b)SMF performs the SM policy association establishment process to establish the SM policy association with the PCF.

[0227] 8) If the request type in step 3 indicates "initial request", the SMF selects the SSC mode for the PDU session. If step 5 is not performed, the SMF can also select the UPF. In the case of request type IPv4 or IPv6, the SMF can allocate an IP address / prefix for the PDU session.

[0228] 9)SMF provides information about the policy control request triggering conditions by executing the SM policy association modification process.

[0229] 10) If the request type indicates "initial request", the SMF can use the selected UPF to start the N4 session establishment process, otherwise it can use the selected UPF to start the N4 session modification process.

[0230] 10a) SMF sends N4 Session Establishment / Modification Request message to UPF. In addition, SMF can provide packet discovery, enforcement and reporting rules for packets to be installed in UPF for PDU session. In the case where SMF allocates CN tunnel information, CN tunnel information can be provided to UPF.

[0231] 10b) The UPF may respond by sending an N4 Session Establishment / Modification Response message. In the case where the CN tunnel information is allocated by the UPF, the CN tunnel information may be provided to the SMF.

[0232] 11)SMF sends a Namf_Communication_N1N2MessageTransfer message to AMF. The Namf_Communication_N1N2MessageTransfer message may include PDU session ID, N2 SM information and N1 SM container.

[0233] The N2 SM information may include PDU Session ID, QoS Flow ID (QFI), QoS Profile, CN Tunnel Information, S-NSSAI from Allowed NSSAI, Session-AMBR, PDU Session Type, User Plane Security Enhancement Information, UE Integrity Protection Maximum Data Rate.

[0234] The N1 SM container may include a PDU Session Establishment Accept message.

[0235] The PDU Session Establishment Accept message may include allowed QoS rules, SSC mode, S-NSSAI and assigned IPv4 address.

[0236] 12)AMF sends an N2 PDU Session Request message to RAN. The message may include N2 SM information and NAS message. The NAS message may include PDU Session ID and PDU Session Establishment Accept message.

[0237] The AMF may send a NAS message including the PDU Session ID and a PDU Session Establishment Accept message. Additionally, the AMF may include the N2 SM information received from the SMF in the N2 PDU Session Request message, and may then send a message including the N2 SM information to the RAN.

[0238] 13) The RAN may perform specific signaling exchanges with the UE related to the information received from the SMF.

[0239] The RAN also allocates RAN N3 tunnel information for the PDU session.

[0240] The RAN forwards the NAS message provided in step 10. The NAS message may include a PDU session ID and N1 SM information. The N1 SM information may include a PDU session establishment accept message.

[0241] The RAN sends a NAS message to the UE only if the required RAN resources are configured and the allocation of the RAN tunnel information is successful.

[0242] 14) RAN sends an N2 PDU Session Response message to AMF. The message may include PDU Session ID, cause and N2 SM information. N2 SM information may include PDU Session ID, (AN) Tunnel Information and a list of allowed / rejected QoS profiles.

[0243] -RAN tunnel information may correspond to the access network address of the N3 tunnel corresponding to the PDU session.

[0244] 15)AMF may send a Nsmf_PDUSession_UpdateSMContext request message to SMF. The Nsmf_PDUSession_UpdateSMContext request message may include N2 SM information. In this document, AMF may forward the N2 SM information received from RAN to SMF.

[0245] 16a) If the N4 session for the PDU session has not been configured, the SMF may start the N4 session establishment procedure with the UPF. Otherwise, the SMF may start the N4 session modification procedure with the UPF. The SMF may provide the AN tunnel information and the CN tunnel information. The CN tunnel information shall be provided only if the SMF selects the CN tunnel information in step 8.

[0246] 16b) UPF may send an N4 session modification response message to SMF.

[0247] 17)SMF sends a Nsmf_PDUSession_UpdateSMContext response message to AMF.

[0248] After this step, AMF can deliver relevant events to SMF.

[0249] 18)SMF sends Nsmf_PDUSession_SMContextStatusNotify message.

[0250] 19) SMF sends information to UE through UPF. More specifically, in the case of PDU type IPv6, SMF can generate IPv6 router advertisements and can send the generated advertisements to UE through N4 and UPF.

[0251] 20) During this process, if the PDU session establishment is unsuccessful, the SMF notifies this to the AMF.

[0252] Figure 9a and Figure 9b The modification process of the PDU session is shown.

[0253] A MAPDU session may be established / managed based on the PDU session modification procedure.

[0254] The PDU session modification procedure may be initiated by the UE or may be initiated by the network.

[0255] 1a) When initiated by the UE, the UE may initiate a PDU session modification procedure by sending a NAS message. The NAS message may include an N1 SM container. The N1 SM container may include a PDU session modification request message, a PDU session ID, and information about the maximum data rate for integrity protection of the UE. The PDU session modification request message may include a PDU session ID, a packet filter, requested QoS information, 5GSM core network capabilities, and the number of packet filters. The maximum data rate for integrity protection of the UE indicates the maximum data rate that the UE can support for UP integrity protection. The number of packet filters indicates the number of packet filters supported for the QoS rules.

[0256] According to the location information of the UE, a NAS message is sent to the appropriate AMF via the RAN. The AMF then sends a Nsmf_PDUSession_UpdateSMContext message to the SMF. The message may include a session management (SM) context ID and an N1 SM container. The N1SM container may include a PDU session modification request message.

[0257] 1b) When initiated by the PCF in a network node, the PCF may notify the SMF of the policy change by initiating the SM policy association modification procedure.

[0258] 1c) When initiated by the UDM in the network node, the UDM can update the subscription data of the SMF by sending a Nudm_SDM_Notification message. The SMF can update the session management subscriber data and send an ACK message to the UDM.

[0259] 1d) When initiated by the SMF in a network node, the SMF can trigger a QoS update.

[0260] When triggered according to above 1a to 1d, SMF can perform the PDU session modification process.

[0261] 1e) When initiated by an AN among network nodes, the AN may notify the SMF when releasing the AN resources to which the QoS flow is mapped. The AN may send an N2 message to the AMF. The N2 message may include a PDU session ID and N2 SM information. The N2 SM information may include a QoS flow ID (QFI), user location information, and an indication that the QoS flow is released. The AMF may send an Nsmf_PDUSession_UpdateSMContext message. The message may include an SM context ID and N2 SM information.

[0262] 2) SMF can send a report on the subscription event by performing the SM policy association modification procedure. If the PDU session modification procedure is triggered by 1b or 1d, this step can be skipped. If dynamic PCC is not deployed in the network, the SMF can apply internal policies to decide to change the QoS profile.

[0263] When PDU session modification only requires UPF operation, steps 3 to 7 which will be described later may not be performed.

[0264] 3a) When initiated by the UE or AN, the SMF may respond to the AMF by sending a Nsmf_PDUSession_UpdateSMContext message. The message may include N2 SM information and N2 SM container. The N2 SM information may include PDU session ID, QFI, QoS profile and session-AMBR. The N1 SM container may include a PDU session modification command. The PDU session modification command may include PDU session ID, QoS rules, QuS rule operations, QoS flow level QoS parameters and session-AMBR.

[0265] The N2 SM information may include information to be sent by the AMF to the AN. The N2 SM information may include a QFI and a QoS profile to inform the AN of adding or modifying one or more QoS flows. If a PDU session modification is requested by a UE for which no user plane resources are configured, the N2 SM information to be delivered to the AN may include information about the establishment of user plane resources.

[0266] The N1 SM container may include a PDU session modification command to be delivered by the AMF to the UE. The PDU session modification command may include QoS rules and QoS flow level QoS parameters.

[0267] 3b) When initiated by SMF, SMF may send Namf_Communication_N1N2MessageTransfer message. The message may include N2 SM information and N1 SM container. N2 SM information may include PDU session ID, QFI, QoS profile and session-AMBR. N1 SM container may include PDU session modification command. PDU session modification command may include PDU session ID, QoS rules and QoS flow level QoS parameters.

[0268] If the UE is in the CM-IDLE state and ATC is activated, the AMF updates and stores the UE context based on the Namf_Communication_N1N2MessageTransfer message, and then steps 3 to 7 described later may be skipped. When the UE enters the reachable state (ie, CM-CONNECTED state), the AMF may send an N1 message to synchronize the UE context with the UE.

[0269] 4) AMF may send an N2 PDU Session Request message to AN. The N2 PDU Session Request message may include the N2 SM information and NAS message received from SMF. The NAS message may include the PDU Session ID and N1 SM container. The N1 SM container may include a PDU Session Modification Command.

[0270] 5) The AN performs AN signaling exchanges with the UE related to the information received from the SMF. For example, in the case of NG-RAN (i.e., gNB or base station), in order to modify the necessary AN resources related to the PDU session, an RRC connection reconfiguration procedure with the UE may be performed.

[0271] 6) The AN sends an N2 PDU Session ACK message in response to the received N2 PDU Session Request. The N2 PDU Session ACK message may include N2 SM information and user location information. The N2 SM information may include a list of accepted / rejected QFIs, AN tunnel information, and PDU Session ID.

[0272] 7)AMF delivers the user location information and N2 SM information received from AN to SMF through Nsmf_PDUSession_UpdateSMContext message. Then, SMF delivers Nsmf_PDUSession_UpdateSMContext message to AMF.

[0273] 8) SMF sends an N4 session modification request message to UPF to update the N4 session of UPF included in the PDU session modification.

[0274] When a new QoS flow is generated, the SMF updates the UL packet detection rules of the new QoS flow together with the UPF.

[0275] 9) In response to receiving the PDU session modification command, the UE sends a NAS message. The NAS message may include the PDU session ID and the N1 SM container. The N1 SM container may include the PDU session modification command ACK.

[0276] 10) AN sends a NAS message to AMF.

[0277] 11)AMF delivers the user location information and N1 SM container received from AN to SMF through Nsmf_PDUSession_UpdateSMContext message. N1 SM container may include PDU session modification command ACK. SMF may deliver Nsmf_PDUSession_UpdateSMContext response message to AMF.

[0278] 12) SMF sends an N4 session modification request message to UPF to update the N4 session of UPF included in the PDU session modification. The message may include the N4 session ID.

[0279] 13) When the SMF interacts with the PCF in step 1b or step 2 above, the SMF may inform the PCF whether the PCC decision can be executed through the SM policy association modification process.

[0280] The SMF may notify the requesting entity of user location information associated with changes to the PDU session.

[0281] <Redundant Transmission>

[0282] Furthermore, in the next generation (ie, fifth generation) of mobile communications, redundant transmission for URLCC is being discussed.

[0283] Fig.10a shows an example of an architecture for redundant transmission, and Fig.10b Another example of an architecture for redundant transmission is shown.

[0284] Reference Fig.10a It can be seen that two N3 tunnels can be created between the NG-RAN and the UPF. Therefore, data can be redundantly transmitted through the two tunnels. The NG-RAN node and the UPF can support packet duplication and elimination.

[0285] Refer to Fig.10b It can be seen that two intermediate UPFs between the UPF and the NG-RAN can support redundant transmission based on the two N3 and N9 tunnels between the NG-RAN node and the UPF. The NG-RAN node and the UPF can support packet duplication and elimination.

[0286] For the URLLC QoS flow of the PDU session for redundant transmission established during or after the establishment of the URLLC QoS flow, there can be two N3 and N9 tunnels between the NG-RAN and the UPF. For downlink traffic, the UPF can duplicate the downlink packets of the QoS flow from the DN and assign the same GTP-U sequence number to the downlink packets. These duplicated packets can be sent to the I-UPF 1 and the I-UPF 2 through the N9 tunnel 1 and the N9 tunnel 2 respectively. Each I-UPF can forward the packets received from the UPF (with the same GTP-U sequence number) to the NG-RAN through the N3 tunnel 1 and the N3 tunnel 2. The NG-RAN can eliminate the duplicate packets based on the GTP-U sequence number. In the case of uplink traffic, the NG-RAN can duplicate the packets of the QoS flow from the UE and assign the same GTP-U sequence number. These duplicate packets can be sent to the I-UPF 1 and the I-UPF 2 through the N3 tunnel 1 and the N3 tunnel 2. Each I-UPF can forward the packets received from the NG-RAN (with the same GTP-U sequence number) to the UPF through the N9 tunnel 1 and the N9 tunnel 2. The UPF can eliminate the duplicate packets based on the GTP-U sequence number.

[0287] <NWDAF (Network Data Analytics Function)>

[0288] The NWDAF that supports UE mobility statistics or analysis can collect UE mobility-related information from network functions (NFs) as well as operations, administration, and maintenance (OAM), and can generate UE mobility statistics or predictions through data analysis.

[0289] The services provided by the NWDAF can be used by, for example, the AMF among several NFs.

[0290] Fig.11 It is an example diagram illustrating the signal flow for the operation of the NWDAF.

[0291] The NWDAF can provide UE mobility-related analysis in the form of statistics or predictions. In Fig.11, it is shown that the application function (AF) is the NF provided with services from the NWDAF. The AF can request analysis via the NEF, and the NEF can provide the request to the NWDAF.

[0292] 1) NF can send a request message to NWDAF to analyze a specific UE or a group of UEs. The message can be, for example, a message based on Nnwdaf_AnalyticsInfo or Nnwdaf_AnalyticsSubscription service. NF can request statistics or predictions. The type of analysis can be UE mobility information. NF can provide UE id or internal group ID in the target of the analysis report.

[0293] 2) If the request is authorized and in order to provide the requested analysis, the NWDAF may subscribe to events of all serving AMFs for notification of UE location changes. This step may not be performed if the NWDAF has already completed the analysis.

[0294] NWDAF subscribes service data to AF. To do this, messages based on Naf_EventExposure_Subscribe or Nnef_EventExposure_Subscribe services can be used.

[0295] NWDAF collects UE mobility information from OAM.

[0296] The NWDAF selects the AMF responsible for the UE or UE group.

[0297] 3) NWDAF performs the requested analysis.

[0298] 4) NWDAF provides the requested UE mobility analysis to NF. To this end, the response message to Nnwdaf_AnalyticsInfo_Request or Nnwdaf_AnalyticsSubscription_Notify message may be used.

[0299] 5-6) If the NF has subscribed to receive notifications for UE mobility analysis, the NWDAF may generate the analyses and provide them to the NF.

[0300] The disclosure of this specification provides a method for solving the above-mentioned problems.

[0301] <Problems to be Solved by the Disclosure of This Specification>

[0302] Research is being conducted to perform network automation by utilizing the information analysis / prediction function of NWDAF, and efforts are being made to efficiently provide mobile edge computing (MEC) services. In particular, research is being conducted to optimize UP paths.

[0303] In the case of 5G services, since more UEs receive real-time services by utilizing more network resources compared to 4G, it is very important to make decisions on information analysis / resource management.

[0304] I. Overview of the Disclosure of This Specification

[0305] I-1. Functions of the first network node (eg, NWDAF)

[0306] According to the disclosure of this specification, the first network node (eg, NWDAF) may obtain information of the NG-RAN serving the UE from the network node.

[0307] The first network node (eg, NWDAF) may obtain information about QoS and data efficiency on the redundant transmission path.

[0308] Furthermore, the first network node (eg, NWDAF) may analyze statistical / predictive values ​​for the efficiency of using the redundant transmission paths.

[0309] Furthermore, the first network node (eg, NWDAF) may send the analyzed statistical values ​​and predicted values ​​to a network node, in particular, the SMF.

[0310] I-2. Functions of the second network node (eg, SMF)

[0311] The second network node (eg, SMF) may determine management and whether to establish a PDU session to which redundant transmission is applied by utilizing the obtained information.

[0312] When it is determined to establish a PDU session supporting redundant transmission, the second network node (e.g., SMF) notifies the PDU Session Anchor (PSA) UPF and NG-RAN of the redundant transmission (note that the message sent to the UE passes through the AMF).

[0313] The second network node (eg, SMF) may obtain information from the NWDAF for determining how to efficiently support redundant transmission of the URLCC service.

[0314] The second network node (eg, SMF) may determine whether redundant transmission should be performed.

[0315] If redundant transmission has been activated, the second network node (eg, SMF) may determine whether redundant transmission should be stopped.

[0316] II. Example of implementation

[0317] II-1. NWDAF assistance to support user plane (UP) optimization

[0318] UP optimization can be supported for edge computing. In edge computing environments, especially for URLLC services, redundant transmission experience-related analysis can be used to support efficient UP resource usage.

[0319] The SMF can decide to perform redundant transmission based on the authorized 5G QoS identifier (5QI), NG-RAN node capabilities and / or operator configuration, and the SMF can therefore notify the PSAUPF and NG-RAN to perform redundant transmission via the N4 interface and N2 information.

[0320] NEDAF can send redundant transmission experience-related analysis to SMF, and it can influence the operator policy configured in SMF to efficiently support redundant transmission of URLLC services, i.e., determine whether redundant transmission should be performed, or should be stopped.

[0321] In various cases, such as when the UPF sends monitoring data to the SMF, as described below, or when data can be collected directly from the RAN, the NWDAF supporting redundant transport experience related analysis may be able to:

[0322] i) Collect UE mobility related information from NF (e.g. AMF or AF) and OAM.

[0323] Specifically, depending on UE mobility, since the NG-RAN to be accessed may be different and the capability related to redundant transmission of the NG-RAN may vary, UE mobility-related information may be collected for confirmation / prediction of validity.

[0324] ii) Collect information about packet drops and / or packet delay measurements from NF (e.g. UPF or SMF) and OAM (also, from NG-RAN).

[0325] This information may be collected for the purpose of determining the status of the backhaul network.

[0326] iii) Collecting efficiency information about redundant transmission from NF (e.g., UPF) and OAM (also, from NG-RAN).

[0327] This information can be used for the purpose of verifying whether the redundant paths are actually used effectively. That is, if sufficient QoS is guaranteed only by packets arriving at path 1, packets arriving at path 2 may not be needed. For example, it is possible to measure which path data is used, which path data is considered as a duplicate packet and discarded, whether the data on each path is actually used, and the success rate of each path.

[0328] iv) Collect information related to PDU sessions established with redundant transport from NF (e.g. SMF) and OAM.

[0329] The information may include the number of PDU sessions or the performance of the PDU sessions. The information may be used for the purpose of confirming / predicting the effectiveness of the PDU sessions to which redundant transmission is applied.

[0330] -Perform data analysis to provide redundant transmission experience statistics or predictions.

[0331] Analysis services from NWDAF can be provided to NF (e.g., SMF).

[0332] The NF (e.g., SMF) receiving this analysis service may include the following in the request.

[0333] -Analysis ID = "Redundant Transmission Experience".

[0334] - The target of the analysis report can be a single UE, any UE or a group of UEs.

[0335] -Analysis filter information may optionally include the following information.

[0336] a. Region of interest;

[0337] bS-NSSAI;

[0338] c.DNN.

[0339] Analysis target period: Indicates the time period for which statistics or predictions are requested.

[0340] II-1. Input Data

[0341] The NWDAF supporting data analysis on redundant transmission experience may be able to collect UE mobility information from OAM, 5GC and AF, and collect service data from AF.

[0342] Furthermore, it may be possible to collect information of PDU sessions established with redundant transmission from NF (e.g., SMF).

[0343] The following table shows UE mobility information.

[0344] [Table 4]

[0345]

[0346] The following table shows the service data related to UE mobility from AF.

[0347] [Table 5]

[0348] information describe UE ID External UE ID (i.e., GPSI) App ID Identifies the application that provided this information UE track (1..max) UE location with timestamp >UE location The geographical area that the UE enters >Timestamp Timestamp of UE entering the area

[0349] Additionally, packet drop and / or packet delay measurements may be entered at different levels of granularity (ie, per QoS flow, per UE, or per GTP-U path).

[0350] The following table shows packet drop and / or packet delay measurements.

[0351] [Table 6]

[0352]

[0353] The following table shows the efficiency measure for redundant transmission.

[0354] [Table 7]

[0355]

[0356] The following table shows the information related to a PDU session established with redundant transmission.

[0357] [Table 8]

[0358] information source describe DNN SMF The name of the data network associated with the URLLC service UP with redundant transmission SMF Ratio of successful redundant transmission settings

[0359] II-2. Output Analysis

[0360] The NWDAF supporting data analysis on redundant transmission experience may send the redundant transmission experience analysis to the NF (eg, SMF).

[0361] The following table shows the redundant transmission experience statistics.

[0362] [Table 9]

[0363]

[0364]

[0365] The following table shows the redundant transmission experience prediction.

[0366] [Table 10]

[0367]

[0368] II-3. Process

[0369] II-3-1. Analysis process

[0370] NWDAF can provide analysis in the form of statistics or forecasts.

[0371] Fig.12 is a signal flow diagram illustrating an example of providing analysis to NF.

[0372] 1) NF may send a request message to NWDAF to analyze a specific UE or a group of UEs. The message may be based on, for example, Nnwdaf_AnalyticsInfo or Nnwdaf_AnalyticsSubscription services. NF may request statistics or predictions. The type of analysis may be redundant transmission experience. NF may provide UE ID or internal group ID in the target of the analysis report. Analysis filter information may optionally contain DNN, S-NSSAI, region of interest, etc.

[0373] 2) If the request is authorized and in order to provide the requested analysis, the NWDAF may subscribe to events of all serving AMFs for notification of location changes, and may subscribe to events of the SMF serving the PDU session on the URLLC service for notification of redundant transmission related information.

[0374] NWDAF can subscribe to service data from AF using Naf_EventExposure_Subscribe service or Nnef_EventExposure_Subscribe.

[0375] The NWDAF may collect UE mobility information, packet measurement information, and / or redundant transmission related information from the OAM.

[0376] If NWDAF already has the requested analysis, this step can be skipped.

[0377] 3) NWDAF performs analysis on the above requested analysis.

[0378] 4) NWDAF can provide the requested analysis results to NF. To this end, Nnwdaf_AnalyticsInfo_Request response message or Nnwdaf_AnalyticsSubscription_Notify message can be used.

[0379] 5-7) In step 1 above, if the NF has requested redundant transmission experience analysis, upon receiving event notification messages from the AMF, AF and OAM, the NWDAF can perform the analysis and provide the analysis to the NF.

[0380] If SMF wants to use analysis, redundant transmission experience analysis can be used to determine how to handle PDU sessions. For example, redundant transmission experience analysis can be used to decide whether redundant transmission should be performed or redundant transmission of PDU sessions for URLCC services should be stopped.

[0381] II-3-2. Functional enhancement of network nodes

[0382] The SMF may be enhanced to obtain information from the NWDAF to decide how to efficiently support redundant transmission of URLCC services.

[0383] SMF, based on the information obtained,

[0384] It may be determined that a redundant transmission should be performed.

[0385] Alternatively, if redundant transmission has been activated, it may be determined that redundant transmission should be stopped.

[0386] NWDAF can be enhanced as follows.

[0387] NWDAF can provide redundant transmission experience statistics and predictions.

[0388] In this specification, for the operation of the Nnwdaf service used in the process, "Redundant Transport Experience" can be added to the analysis provided by NWDAF as follows.

[0389] II-3-3. Changes to the Standard Specification of the Behavior of the Nnwdaf Service

[0390] The following table shows the services provided by NWDAF.

[0391] [Table 11]

[0392]

[0393] The table below shows the analysis information provided by NWDAF.

[0394] [Table 12]

[0395]

[0396]

[0397] Hereinafter, an example of using analysis will be described.

[0398] III. Examples of using analytics

[0399] III-1. Support of redundant transmission on N3 / N9 interface

[0400] During or after the URLLC QoS flow establishment process, if the SMF decides that redundant transmission can be performed based on the authorized 5QI, NG-RAN node capabilities and / or operator configuration, the SMF can notify the UPF and NG-RAN to perform redundant transmission via the N4 interface, and the N2 information can be delivered. In this case, the NG-RAN can provide different routing information (e.g., different IP addresses) in the tunnel information. Depending on the network deployment configuration, this routing information can be mapped to disjoint transport layer paths.

[0401] In the case of deployment option using NWDAF for URLLC services, the SMF may decide that redundant transmission should be performed based on analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0402] If duplicate transmission is performed on the N3 / N9 interface, for each downlink packet of the QoS flow received by the UPF from the DN, the UPF can duplicate the packet and assign the same GTP-U sequence number to them for redundant transmission.

[0403] NG-RAN eliminates duplicate packets based on the GTP-U sequence number and then forwards the PDU to the UE.

[0404] For each uplink packet of a QoS flow received by the NG-RAN from the UE, the NG-RAN duplicates the packet and assigns them the same GTP-U sequence number for redundant transmission. These packets are sent to the UPF via two N3 tunnels. The UPF can eliminate duplicate packets based on the GTP-U sequence number.

[0405] UPF and NG-RAN send packets through one tunnel or two tunnels for each QoS flow based on SMF instructions.

[0406] III-2. Changes to the standard specification of the UE-requested PDU session establishment procedure

[0407] Already referred to Figure 8a and Figure 8b The PDU session establishment process is described. The following mainly describes the differences.

[0408] In step 4, the SMF may determine whether the PDU session requires redundancy.

[0409] In the case of using NWDAF for URLCC service, SMF can determine whether the PDU session requires redundancy, i.e., whether redundant transmission should be performed, based on the analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration. If the UE request is considered invalid, the SMF may decide not to accept the establishment of the PDU session.

[0410] In step 10a, if the SMF decides to perform redundant transmission for the PDU session, the SMF may instruct the UPF to use one CN tunnel information as a redundant tunnel for the PDU session.

[0411] In the case of using NWDAF for URLCC services, the SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0412] If the SMF decides to use two I-UPFs for redundant transmission between UPF and NG-RAN, the SMF may request the corresponding CN tunnel information and provide it to the I-UPF and UPF. In the case of using NWDAF for URLLC services, the SMF may decide that redundant transmission should be performed based on an analysis of the redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration. The SMF may instruct the UPF to eliminate duplicate packets for QoS flows in the uplink direction. The SMF may instruct the UPF to use the CN tunnel information as a redundant tunnel for the PDU session.

[0413] In step 11, the CN tunnel information may correspond to the core network address of the N3 tunnel corresponding to the PDU session. If the PDU session for redundant transmission includes two CN tunnel information, the SMF may indicate to the NG-RAN that one of the CN tunnel information is used as a redundant tunnel for the PDU session.

[0414] If the RAN receives two CN tunnel information for the PDU session for redundant transmission in step 12, then in step 13, the RAN may allocate two AN tunnel information and indicate to the SMF that one of the AN tunnel information is used as a redundant tunnel for the PDU session.

[0415] In step 16a, if the SMF decides to perform redundant transmission for one or more QoS flows, the SMF may instruct the UPF to perform packet duplication for the QoS flows in the downlink direction. In the case of redundant transmission using two I-UPFs for one or more QoS flows, the SMF may provide AN tunnel information to the two I-UPFs and instruct the UPF to perform packet duplication.

[0416] SMF can provide UPF with the UL tunnel information and DL tunnel information of the two I-UPFs.

[0417] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0418] III-3. Changes to the standard specification of the PDU session modification process

[0419] Already referred to Figure 9a and Figure 9b The PDU session modification process is described. The following mainly explains the differences.

[0420] In step 2a, if redundant transmission for the PDU session is not activated, the SMF may decide to perform redundant transmission for the QoS flow, and the SMF may instruct the UPF to perform packet duplication and elimination for the QoS flow.

[0421] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0422] If redundant transmission for a PDU session has been activated, and the SMF decides to stop redundant transmission, the SMF may instruct the UPF to release the CN tunnel information used as the redundant tunnel for the PDU session, and may also instruct the UPF to stop packet duplication and elimination of the corresponding QoS flow.

[0423] In the case of using NWDAF for URLLC services, SMF can decide to stop redundant transmission based on the analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0424] If redundant transmission of the PDU session has not been activated and the SMF decides to utilize two I-UPFs between PSA and NG-RAN to perform redundant transmission of QoS flows, the SMF may send an N4 session establishment request message to the I-UPF. The message may include the UL CN tunnel information of the UPF and a request to allocate the CN tunnel information.

[0425] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0426] In the case of using NWDAF for URLLC services, SMF can decide to stop redundant transmission based on the analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0427] In step 3a, if the SMF decides to activate redundant transmission, the SMF may include additional CN tunnel information in the N2 SM information.

[0428] If redundant transmission for a PDU session has been activated and the SMF decides to stop redundant transmission, the SMF may release the AN tunnel and request the UPF to stop packet duplication and elimination associated with the redundant tunnel of the PDU session.

[0429] In the case of using NWDAF for URLLC services, SMF can decide to stop redundant transmission based on the analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0430] In step 3b, if redundant transmission for the PDU session has been activated and the SMF decides to stop redundant transmission, the SMF may instruct the RAN to release the AN tunnel and stop packet duplication and elimination associated with the redundant tunnel of the PDU session.

[0431] In the case of using NWDAF for URLLC services, SMF can decide to stop redundant transmission based on the analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0432] In step 8, if additional AN tunnel information is returned by RAN, SMF can inform UPF of the AN tunnel information for redundant transmission. In the case of using two I-UPFs for redundant transmission, SMF can provide AN tunnel information to the two I-UPFs. If CN tunnel information of two I-UPFs is allocated by UPF, SMF can provide two DL CN tunnel information to UPF.

[0433] III-4. Changes to the standard specification of the NG-RAN inter-RAN handover procedure based on Xn

[0434] Fig.13 is an example diagram illustrating an Xn-based NG-RAN inter-handover procedure without user plane reallocation.

[0435] In the following, Fig.13 Among the steps shown, only the contents related to redundant transmission will be described.

[0436] In step 4, in the case of using NWDAF for URLLC service, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0437] In step 6, if redundant transmission is performed for one or more QoS flows of the PDU session, two CN tunnel information may be sent, and the SMF may indicate to the target NG-RAN that one of the two CN tunnels is used as a redundant tunnel for the PDU session.

[0438] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0439] Fig.14a and Fig.14b is an example diagram illustrating the Xn-based NG-RAN inter-handover procedure when an intermediate UPF exists.

[0440] If redundant transmission is performed for one or more QoS flows of a PDU session to be handed over to the target NG-RAN, the SMF may select two intermediate UPFs (i.e., I-UPFs) and establish two N3 and N9 tunnels between the target NG-RAN and the UPF via the two I-UPFs.

[0441] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0442] Hereinafter, all the steps shown in FIG. 14 will not be described again, and only the contents related to redundant transmission will be described.

[0443] In step 3b, the UPF may send an N4 session establishment response message to the SMF. The UPF may provide the CN tunnel information to the SMF. If redundant transmission is performed for one or more QoS flows of the PDU session, the UPF may provide two CN tunnel information to the SMF and instruct the SMF to use one of the CN tunnel information as a redundant tunnel for the PDU session. The UPF may associate the CN tunnel information with the UL packet detection provided by the SMF.

[0444] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0445] In step 4b, the I-UPF may send an N4 session establishment response message to the SMF. The UL and DL CN tunnel information of the I-UPF may be sent to the SMF.

[0446] If the SMF selects two intermediate UPFs (i.e., I-UPFs) to perform redundant transmission for the PDU session, steps 4a and 4b may be performed between the SMF and each I-UPF. In the case of using NWDAF for URLLC services, the SMF may decide that redundant transmission should be performed based on analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0447] In step 5, if redundant transmission is performed for one or more QoS flows of the PDU session, the SMF may provide two DL CN tunnel information to the UPF and indicate to the UPF that one of the DL CN tunnel information is used as a redundant tunnel PDU session. In the case of using NWDAF for URLLC service, the SMF may decide that redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0448] Fig.15 is an example diagram illustrating Xn-based inter-NG-RAN handover when the intermediate UPF is reallocated.

[0449] In the following, no further description will be given. Fig.15 All steps shown in , and only those related to redundant transmission will be described.

[0450] The SMF may send an N4 Session Modification Request message to the PDU Session Anchor. The DL CN tunnel information of the target UPF may be included in this message. If redundant transmission is performed for one or more QoS flows of the PDU session, the SMF may provide two DL CN tunnel information to the UPF and indicate to the UPF that one of the DL CN tunnel information is used as a redundant tunnel for the PDU session.

[0451] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0452] III-5. Changes to the standard specification for N2-based handover procedures between NG-RAN nodes

[0453] Fig.16a and Fig.16b This is an example diagram illustrating the N2-based handover process between NG-RAN nodes in an environment without an Xn interface.

[0454] In the following, no further description will be given. Fig.16a and Fig.16b All steps shown are described, and only those related to redundant transmission will be described.

[0455] In step 5, if redundant transmission is performed for one or more QoS flows of the PDU session, the SMF can select two intermediate UPFs to support redundant transmission based on the two N3 and N9 tunnels between the T-RAN and the UPF.

[0456] In step 6a, if redundant transmission is performed on one or more QoS flows of the PDU session and different CN tunnel information needs to be used, the SMF can provide two CN tunnel information to the UPF if the CN tunnel information is allocated by the SMF. In addition, the SMF can indicate to the UPF that one CN tunnel information is used as a redundant tunnel for the PDU session.

[0457] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0458] In step 6b, if redundant transmission is performed for one or more QoS flows of the PDU session, the UPF may provide two CN tunnel information of the UPF to the SMF and instruct the SMF to use one CN tunnel information as a redundant tunnel for the PDU session. The UPF may associate the CN tunnel information with the UL packet detection rule provided by the SMF.

[0459] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0460] In step 7, if redundant transmission is performed for one or more QoS flows of the PDU session, two UL CN tunnel information may be included in the N2 SM information. In the case of using NWDAF for URLLC service, SMF may decide whether redundant transmission should be performed based on analysis of redundant transmission experience and authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0461] In step 10, if redundant transmission is performed on one or more QoS flows of the PDU session, the T-RAN may include two AN tunnel information of the PDU session in the N2 SM information.

[0462] Figures 17a to 17c This is an example diagram illustrating the N2-based handover process between NG-RAN nodes in an environment without an Xn interface.

[0463] In the following, it will not be described Figures 17a to 17c All steps shown are described, and only those related to redundant transmission will be described.

[0464] If redundant transmission is performed for one or more QoS flows of a PDU session, two N3AN tunnel information of the T-RAN or two DL CN tunnel information of two T-UPFs may be provided, and the SMF may indicate to the UPF that one of the AN / CN tunnel information is used as a redundant tunnel for the PDU session.

[0465] In the case of using NWDAF for URLLC services, SMF can decide whether redundant transmission should be performed based on the analysis of redundant transmission experience and the authorized 5QI, NG-RAN node capabilities and / or operator configuration.

[0466] IV. Summary of the Disclosure of This Specification

[0467] According to the disclosure of this specification, the first network control node (eg, NWDAF) may collect and analyze information about redundant transmission paths.

[0468] The second network control node (eg, SMF) may obtain the analyzed information and determine whether to establish a PDU session and a UP resource management method for applying redundant transmission.

[0469] Fig.18 A block diagram of a processor in which the disclosed contents of this specification are implemented is shown.

[0470] If you can refer to Fig.18 As can be seen, the processor 1020 implementing the disclosure of this specification may include multiple circuits for implementing the proposed functions, processes and / or methods described herein. For example, the processor 1020 may include a first circuit 1020-1, a second circuit 1020-2, and a third circuit 1020-3. In addition, although not shown, the processor 1020 may include more circuits. Each circuit may include multiple transistors.

[0471] The processor 1020 may be referred to as an application specific integrated circuit (ASIC) or an application processor (AP), and include at least one of a digital signal processor (DSP), a central processing unit (CPU), and / or a graphics processing unit (GPU).

[0472] The processor may be included in a UE, a base station, an AMF or an SMF.

[0473] A case where the processor is included in the AMF will be described.

[0474] The first circuit 1020-1 of the processor included in the SMF may obtain analysis information from a network data analysis function (NWDAF) node. The obtained analysis information may include experience analysis information about redundant transmission.

[0475] The second circuit 1020-2 of the processor included in the SMF may determine, based on the analysis information, to redundantly transmit the PDU session through two tunnels during a process related to the PDU session.

[0476] The procedures related to the PDU session may include one or more of a PDU session establishment procedure, a PDU session modification procedure, and a switching procedure.

[0477] The second circuit 1020-2 of the processor included in the SMF may make a determination taking into account an authorized 5G QoS identifier (5QI), NG-RAN node capabilities, and / or operator configuration.

[0478] Experience analysis information about redundant transmission may include: Data Network Name (DNN); observed statistics; and the percentage of PDU sessions with redundant transmission that are efficiently used by the UE, any UE, or a group of UEs.

[0479] The analysis information can be derived by a network data analysis function (NWDAF) node based on one or more of the following: uplink (UL) / downlink (DL) packet drop ratio, UL / DL packet drop rate and / or number of packets due to redundant transmissions, and successful UL / DL transmission rate and / or number of packets.

[0480] The third circuit 1020-3 of the processor included in the SMF may select two intermediate user plane functions (I-UPFs) when performing redundant transmission of one or more QoS flows of a PDU session to be switched to a target NG-RAN.

[0481] A fourth circuit (not shown) of the processor included in the SMF may instruct the UPF to perform packet duplication on the QoS flow in the downlink direction when the SMF node decides to perform redundant transmission on one or more QoS flows.

[0482] A fifth circuit (not shown) of the processor included in the SMF may release the AN tunnel and request the UPF to stop packet duplication and elimination associated with the redundant tunnel of the PDU session when redundant transmission has been activated on the PDU session and the SMF decides to stop redundant transmission.

[0483] Fig.19 A wireless communication system according to an embodiment is illustrated.

[0484] Reference Fig.19 , a wireless communication system may include a first device 100a and a second device 100b.

[0485] The first device 100a may be a UE described in the disclosure of this specification. Alternatively, the first device 100a may be a base station, a network node, a transmitting terminal, a receiving terminal, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with a self-driving function, a connected car, a drone (unmanned aerial vehicle (UAV)), an artificial intelligence (AI) module, a robot, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a climate / environmental device, a device related to 5G services, or a device related to the field of the fourth industrial revolution.

[0486] The second device 100b may be a network node (e.g., AMF or MME) described in the disclosure of this specification. Alternatively, the second device 100b may be a base station, a network node, a transmitting terminal, a receiving terminal, a radio device, a wireless communication device, a vehicle, a vehicle equipped with a self-driving function, a connected car, a drone (unmanned aerial vehicle (UAV)), an artificial intelligence (AI) module, a robot, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a climate / environmental device, a device related to 5G services, or a device related to the field of the fourth industrial revolution.

[0487] For example, UE may include a cellular phone, a smart phone, a laptop computer, a terminal for digital broadcasting, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation, a plate PC, a tablet PC, an ultrabook, a wearable device (e.g., a watch type terminal (smart watch), a glasses type terminal (smart glasses), a head mounted display (HMD)), etc. For example, the HMD may be a display device in a form worn on the head. For example, the HMD may be used to implement VR, AR, or MR.

[0488] For example, a drone may be a flying vehicle that is flown by a wireless control signal without a person on the flying vehicle. For example, a VR device may include a device that realizes an object or background of a virtual world. For example, an AR device may include a device that realizes an object or background of a virtual world by connecting it to an object or background of a real world. For example, an MR device may include a device that realizes an object or background of a virtual world by merging it with an object or background of a real world. For example, a hologram device may include a device that realizes a 360-degree stereoscopic graphic image by recording and playing back stereoscopic graphic information using the interference phenomenon of light beams generated when two lasers meet, which is called holographic technology. For example, a public safety device may include a video relay device or an imaging device that can be worn on the user's body. For example, an MTC device and an IoT device may be a device that does not require direct human intervention or manipulation. For example, an MTC device and an IoT device may include a smart meter, a vending machine, a thermometer, a smart light bulb, a door lock, or various sensors. For example, a medical device may be a device for the purpose of diagnosing, treating, alleviating, disposing, or preventing a disease. For example, a medical device may be a device for the purpose of diagnosing, treating, alleviating, or correcting an injury or obstacle. For example, a medical device may be a device for the purpose of inspecting, replacing, or modifying a structure or function. For example, a medical device may be a device for the purpose of controlling pregnancy. For example, a medical device may include a device for medical treatment, a device for operation, a device for (external) diagnosis, a hearing aid, or a device for surgery. For example, a safety device may be a device installed to prevent possible dangers and maintain safety. For example, a safety device may be a camera, CCTV, a recorder, or a black box. For example, a Fintech device may be a device capable of providing financial services (such as mobile payments). For example, a Fintech device may include a payment device or a point of sale (POS). For example, a climate / environmental device may include a device for monitoring or predicting the climate / environment.

[0489] The first device 100a may include at least one processor (e.g., processor 1020a), at least one memory (e.g., memory 1010a), and at least one transceiver (e.g., transceiver 1031a). The processor 1020a may perform the above functions, processes, and / or methods. The processor 1020a may execute one or more protocols. For example, the processor 1020a may execute one or more layers of a radio interface protocol. The memory 1010a is connected to the processor 1020a and may store various forms of information and / or instructions. The transceiver 1031a is connected to the processor 1020a and may be controlled to send and receive radio signals.

[0490] The second device 100b may include at least one processor (e.g., processor 1020b), at least one memory device (e.g., memory 1010b), and at least one transceiver (e.g., transceiver 1031b). The processor 1020b may perform the above functions, processes, and / or methods. The processor 1020b may implement one or more protocols. For example, the processor 1020b may implement one or more layers of a radio interface protocol. The memory 1010b is connected to the processor 1020b and may store various forms of information and / or instructions. The transceiver 1031b is connected to the processor 1020b and may be controlled to send and receive radio signals.

[0491] The memory 1010a and / or the memory 1010b may be connected inside or outside the processor 1020a and / or the processor 1020b, respectively, and may be connected to another processor through various techniques such as a wired or wireless connection.

[0492] The first device 100a and / or the second device 100b may have one or more antennas. For example, the antenna 1036a and / or the antenna 1036b may be configured to transmit and receive radio signals.

[0493] Fig. 20 A block diagram of a network node according to an embodiment is illustrated.

[0494] In particular, Fig. 20 is a diagram illustrating in detail a case in which a base station is divided into a central unit (CU) and a distributed unit (DU).

[0495] Reference Fig. 20 , base stations W20 and W30 can be connected to the core network W10. Base station W30 can be connected to the adjacent base station W20. For example, the interface between base stations W20 and W30 and the core network W10 can be called NG. The interface between base station W30 and the adjacent base station W20 can be called Xn.

[0496] The base station W30 can be divided into CU W32 and DU W34, W36. That is, the base station W30 can be divided and operated in layers. CU W32 can be connected to one or more DU W34, W36. For example, the interface between CU W32 and DU W34, W36 can be called F1. CU W32 can perform the functions of the high layer of the base station. DU W34, W36 can perform the functions of the low layer of the base station. For example, CU W32 can be a logical node of the radio resource control (RRC), service data adaptation protocol (SDAP) and packet data convergence protocol (PDCP) layers of the host base station (e.g., gNB). DU W34, W36 can be a logical node of the radio link control (RLC), medium access control (MAC) and physical (PHY) layers of the host base station. Alternatively, CU W32 can be a logical node of the RRC and PDCP layers of the host base station (e.g., en-gNB).

[0497] The operation of DU W34, W36 can be partially controlled by CU W32. One DU W34, W36 can support one or more cells. One cell can be supported by only one DU W34, W36. One DU W34, W36 can be connected to one CU W32, and one DU W34, W36 can be connected to multiple CUs through appropriate implementation.

[0498] Fig.21 is a block diagram illustrating a configuration of a UE according to an embodiment.

[0499] Specifically, Fig.21 The UE 100 shown in FIG. 1 is a more detailed example of Fig.19 Figure 1 of the first device.

[0500] The UE includes a memory 1010, a processor 1020, a transceiver 1031, a power management module 1091, a battery 1092, a display 1041, an input unit 1053, a speaker 1042, a microphone 1052, a Subscriber Identity Module (SIM) card, and one or more antennas.

[0501] The processor 1020 may be configured to implement the proposed functions, processes and / or methods described in this specification. The layers of the wireless interface protocol may be implemented in the processor 1020. The processor 1020 may include an application specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The processor 1020 may be an application processor (AP). The processor 1020 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modulator and demodulator (modem). An example of the processor 1020 may be a processor composed of Made by Snapdragon TM Series processors, Manufactured by EXYNOS TM Series processors, A series processors manufactured by Made by HELIO TM Series processors, ATOM manufactured TM series processors or corresponding next-generation processors.

[0502] The power management module 1091 manages the power of the processor 1020 and / or the transceiver 1031. The battery 1092 supplies power to the power management module 1091. The display 1041 outputs the result processed by the processor 1020. The input unit 1053 receives input to be used by the processor 1020. The input unit 1053 may be displayed on the display 1041. The SIM card is an integrated circuit for securely storing an International Mobile Subscriber Identity (IMSI) and related keys, which is used to identify subscribers in mobile phone devices such as mobile phones and computers. Many types of contact address information can be stored in a SIM card.

[0503] The memory 1010 is connected to the processor 1020 in a manner that operates and stores various types of information to operate the processor 1020. The memory may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium, and / or other storage devices. When the embodiment is implemented in software, the technology described in this specification may be implemented in a module (e.g., a process, a function, etc.) for performing the functions described in this specification. The module may be stored in the memory 1010 and executed by the processor 1020. The memory may be implemented inside the processor 1020. Alternatively, the memory 1010 may be implemented outside the processor 1020 and may be communicatively connected to the processor 1020 by various means known in the art.

[0504] The transceiver 1031 is connected to the processor 1020 in a manner of operating and sending and / or receiving radio signals. The transceiver 1031 includes a transmitter and a receiver. The transceiver 1031 may include a baseband circuit for processing radio frequency signals. The transceiver controls one or more antennas to send and / or receive radio signals. In order to initiate communication, the processor 1020 transmits command information to the transceiver 1031 to send a radio signal configuring voice communication data. The antenna is used to send and receive radio signals. When a radio signal is received, the transceiver 1031 can transmit a signal to be processed by the processor 1020 and convert the signal to baseband. The processed signal can be converted into audible or readable information output by the speaker 1042.

[0505] Speaker 1042 outputs sound related results processed by processor 1020. Microphone 1052 receives sound related input to be used by processor 1020.

[0506] The user inputs command information such as a phone number by voice activation using the microphone 1052 or pressing (or touching) a button of the input unit 1053. The processor 1020 processes to perform appropriate functions such as receiving command information, calling a phone number, etc. Operation data on driving may be extracted from the SIM card or the memory 1010. In addition, the processor 1020 may display command information or driving information on the display 1041 so that the user recognizes it or for convenience.

[0507] Fig. 22 A detailed example Fig.19 17 or a detailed block diagram of a transceiver of the first device shown in FIG. 17 .

[0508] Reference Fig. 22 , the transceiver 1031 includes a transmitter 1031-1 and a receiver 1031-2. The transmitter 1031-1 includes: a discrete Fourier transform (DFT) unit 1031-11, a subcarrier mapper 1031-12, an inverse fast Fourier transform (IFFT) unit 1031-13 and a CP insertion unit 1031-14, and a radio transmitter 1031-15. The transmitter 1031-1 may also include a modulator. In addition, for example, a scrambling unit (not shown), a modulation mapper (not shown), a layer mapper (not shown) and a layer permutator (not shown) may be further included, and may be arranged before the DFT unit 1031-11. That is, in order to prevent an increase in the peak-to-average power ratio (PAPR), the transmitter 1031-1 transmits information through the DFT 1011-11 before mapping the signal to the subcarrier. After subcarrier mapping by the subcarrier mapper 1031 - 12 of the signal spread (or precoded in the same sense) by the DFT unit 1031 - 11 , the signal on the time axis is operated by the IFFT unit 1031 - 13 .

[0509] The DFT unit 1031-11 outputs a complex value symbol by performing DFT on the input symbol. For example, when Ntx symbols are input (Ntx is a natural number), the DFT size is Ntx. The DFT unit 1031-11 may be referred to as a transform precoder. The subcarrier mapper 1031-12 maps the complex symbol to each subcarrier in the frequency domain. The complex symbol may be mapped to a resource element corresponding to a resource block allocated for data transmission. The subcarrier mapper 1031-12 may be referred to as a resource element mapper. The IFFT unit 1031-13 outputs a baseband signal for data as a time domain signal by performing IFFT on the input symbol. The CP insertion unit 1031-14 copies a portion of the rear portion of the baseband signal of the data and inserts it into the front portion of the baseband signal of the data. Inter-symbol interference (ISI) and inter-carrier interference (ICI) are prevented by CP insertion, so that orthogonality can be maintained even in a multipath channel.

[0510] On the other hand, the receiver 1031-2 includes a radio receiver 1031-21, a CP remover 1031-22, an FFT unit 1031-23, an equalizer 1031-24, etc. The radio receiver 1031-21, the CP remover 1031-22, and the FFT unit 1031-23 of the receiver 1031-2 perform the reverse functions of the radio transmitter 1031-15, the CP insertion unit 1031-14, and the IFFT unit 1031-13 of the transmitter 1031-1. The receiver 1031-2 may also include a demodulator.

[0511] <Scenarios in which the Disclosure of This Specification Can Be Applied>

[0512] Although not limited to this, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the disclosed contents of this specification disclosed herein can be applied to various fields requiring wireless communication and / or connection between devices (e.g., 5G).

[0513] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise indicated, the same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks and / or functional blocks.

[0514] Fig.23 A communication system 1 to which the disclosure of this specification is applied is exemplified.

[0515] Reference Fig.23, the communication system 1 applied to the disclosure of this specification includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a radio access technology (e.g., 5G new RAT (NR), long term evolution (LTE)), and may be referred to as a communication / wireless / 5G device. Although not limited to this, the wireless device may include a robot 100a, a vehicle 100b-1, 100b-2, a virtual reality (XR) device 100c, a handheld device 100d and a home appliance 100e, an Internet of Things (IoT) device 100f, and an AI device / server 400. For example, a vehicle may include a vehicle equipped with a wireless communication function, an autonomous driving vehicle, a vehicle capable of performing inter-vehicle communication, and the like. Here, the vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device includes an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) set in a vehicle, a television, a smart phone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart tablets, wearable devices (e.g., smart watches, smart glasses), computers (e.g., laptop computers), etc. Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device 200a may operate as a base station / network node corresponding to other wireless devices.

[0516] The wireless devices 100a to 100f may be connected to the network 300 via the base station 200. Artificial intelligence (AI) technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a super 5G network. Although the wireless devices 100a to 100f may communicate with each other via the base station 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without passing through the BS 200 / network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0517] Wireless communication / connection 150a, 150b, and 150c may be established between the wireless devices 100a to 100f and the base station 200. Herein, wireless communication / connection may be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)), etc.). The wireless devices 100a to 100f and the base station 200 / wireless devices 100a to 100f may send radio signals to each other through the wireless communication / connection 150a, 150b, and 150c. For example, the wireless communication / connection 150a, 150b, and 150c may send / receive signals through various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of a resource allocation process may be performed based on various proposals of the present disclosure.

[0518] In the above, the preferred embodiment has been described exemplarily, but the disclosure of this specification is not limited to such specific embodiment. Therefore, the disclosure of this specification can be modified, changed or improved in various forms within the scope of the claims and within the specification.

[0519] In the above exemplary system, the method is described based on a flowchart as a series of steps or blocks, but is not limited to the order of the steps described, and some steps may occur in a different order or simultaneously with other steps as described above. In addition, those skilled in the art will understand that the steps shown in the flowchart are not exclusive, and other steps may be included or one or more steps of the flowchart may be deleted without affecting the scope of the rights.

[0520] The claims described herein may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. In addition, the technical features of the method claims of this specification and the technical features of the device claims of this specification may be combined to be implemented as a device, and the technical features of the method claims of this specification and the technical features of the device of this specification may be combined and implemented as a method.

Claims

1. A method performed by a session management function SMF, the method comprising the following steps: Establish a protocol data unit PDU session; Get redundant transmission experience analysis from the network data analysis function NWDAF; as well as Based on the redundant transmission experience analysis, determining whether to i) perform redundant transmission for the PDU session or ii) stop redundant transmission that has been activated for the PDU session, The redundant transmission experience analysis includes: Data network name DNN; Information related to the redundant transmission experience predicted during the analysis target period; and The percentage of time slots from among the predicted time slots that are associated with said PDU session having redundant transmission.

2. The method according to claim 1, wherein: Whether to i) perform redundant transmission or (ii) stop redundant transmission is determined during the PDU Session Modification procedure.

3. The method according to claim 1 or 2, wherein: In addition to the redundant transmission experience analysis, it is determined whether to i) perform redundant transmission or (ii) stop redundant transmission based on the authorized 5G QoS identifier 5QI, NG-RAN node capabilities and / or operator configuration.

4. The method according to claim 1 or 2, wherein: The redundant transmission experience analysis is derived by the NWDAF based on one or more of the following: Uplink UL / downlink DL packet discard rate, UL / DL packet drop rate and / or number of packets due to redundant transmissions, and Successful UL / DL transmission rate and / or number of packets.

5. The method according to claim 1 or 2, wherein: Based on performing redundant transmission for one or more QoS flows of the PDU session to be handed over to the target next generation radio access network NG-RAN, the method further includes: selecting two intermediate user plane functions I-UPF.

6. The method according to claim 1 or 2, wherein: Based on determining to perform the redundant transmission, the method further includes: instructing the UPF to perform packet duplication and elimination on the QoS flow.

7. The method according to claim 1 or 2, wherein: Based on determining to stop the redundant transmission, the method further includes: instructing the UPF to release core network CN tunnel information used as a redundant tunnel for the PDU session, and also instructing the UPF to stop packet duplication and elimination of the QoS flow.

8. A session management function SMF, the SMF comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory is used to store instructions and is operatively electrically connected to the at least one processor, wherein the instructions are executed by the at least one processor to perform operations including: Establish a protocol data unit PDU session; Obtain redundant transmission experience analysis from the network data analysis function NWDAF; and Based on the redundant transmission experience analysis, determining whether to i) perform redundant transmission for the PDU session or ii) stop redundant transmission that has been activated for the PDU session, The redundant transmission experience analysis includes: Data network name DNN; Information related to the redundant transmission experience predicted during the analysis target period; and The percentage of time slots from among the predicted time slots that are associated with said PDU session having redundant transmission.

9. The SMF according to claim 8, wherein: The operations also include performing the method according to any one of claims 2 to 7.

10. A user equipment UE, the UE comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory is used to store instructions and is operatively electrically connected to the at least one processor, wherein the instructions are executed by the at least one processor to perform operations including: Establish a protocol data unit PDU session; Send non-access stratum NAS message, The NAS message includes a PDU session modification request and an identifier ID of the PDU session. wherein the NAS message is forwarded by the radio access network RAN ​​to the access and mobility management function AMF, The PDU session modification request is forwarded by the AMF to the session management function SMF. Wherein, based on redundant transmission experience analysis, determining to perform redundant transmission for the PDU session; receiving, from the RAN, access network AN specific signaling from the RAN, the AN specific signaling being related to information received from the SMF, The AN specific signaling includes an N1 SM container, and the N1 SM container includes a PDU session modification command. The redundant transmission experience analysis includes: Data network name DNN; Information related to the redundant transmission experience predicted during the analysis target period; and The percentage of time slots from among the predicted time slots that are associated with said PDU session having redundant transmission.

11. The UE according to claim 10, wherein: In addition to the redundant transmission experience analysis, the redundant transmission is determined to be performed based on the authorized 5G QoS identifier 5QI, NG-RAN node capabilities and / or operator configuration.

12. The UE according to claim 10 or 11, wherein: The redundant transmission experience analysis is derived by the network data analysis function NWDAF based on one or more of the following: Uplink UL / downlink DL packet discard rate, UL / DL packet drop rate and / or number of packets due to redundant transmissions, and Successful UL / DL transmission rate and / or number of packets.

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