Dual steering-related communication

Abstract

A disclosure of the present specification provides a method for performing communication by an SMF. The method may comprise the steps of: receiving, from an AMF, an SM context request message related to a PDU session; and transmitting, to the AMF, a message for transferring N2 SM information.

Description

Communication related to dual steering

[0001] This specification relates to mobile communications.

[0002] 3GPP (3rd Generation Partnership Project) LTE (Long-Term Evolution) is a technology designed to enable high-speed packet communications. Numerous approaches have been proposed to achieve LTE's goals of reducing costs for users and operators, improving service quality, expanding coverage, and increasing system capacity. 3GPP LTE's high-level requirements include reduced cost per bit, improved service availability, flexible use of frequency bands, a simple architecture, open interfaces, and adequate power consumption for terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work on developing requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components necessary to successfully standardize NR, meeting both urgent market needs and the longer-term requirements outlined by the ITU Radio communication sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. NR must also be able to utilize any spectrum band up to at least 100 GHz, ensuring that it remains available for wireless communications well into the future.

[0004] NR aims to be a single technology framework that addresses all deployment scenarios, usage scenarios, and requirements, including enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC), and Ultra-Reliable and Low Latency Communications (URLLC). NR must be inherently forward-compatible.

[0005] A dual-steering scheme is being discussed, whereby a terminal registers via two 3GPP access points. However, the network, according to prior art, cannot support dual-steering of terminals.

[0006] According to one embodiment of the present disclosure, a method for an SMF to perform communication is provided. The method may include the steps of receiving an SM context request message related to a PDU session from an AMF; and transmitting a message for transferring N2 SM information to the AMF.

[0007] According to one embodiment, a device implementing the method is provided.

[0008] According to one embodiment of the present disclosure, a method for an AMF to perform communication is provided. The method may include the steps of: receiving a PDU session establishment request message from a User Equipment (UE); transmitting an SM context request message related to the PDU session to an SMF; and receiving a message for conveying N2 SM information from the SMF.

[0009] According to one embodiment, a device implementing the method is provided.

[0010] According to one embodiment of the present disclosure, a method for a UE to perform communication is provided. The method may include the steps of transmitting a registration request message to an AMF; receiving a registration acceptance message from the AMF; and transmitting a PDU session establishment request message to an SMF via the AMF.

[0011] According to one embodiment, a device implementing the method is provided.

[0012] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0013] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0014] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0015] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0016] Figures 5 and 6 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0017] Figures 7 and 8 illustrate examples of a PDU session establishment procedure to which the implementation of the present specification applies.

[0018] Figure 9 is an example diagram showing an example of an architecture for implementing the concept of network slicing.

[0019] Figure 10 is an example diagram showing another example of an architecture for implementing the concept of network slicing.

[0020] FIG. 11a illustrates a first example of multiple connections according to an embodiment of the disclosure of the present specification. FIG. 11b illustrates a second example of multiple connections according to an embodiment of the disclosure of the present specification. FIG. 11c illustrates a third example of multiple connections according to an embodiment of the disclosure of the present specification. FIG. 11d illustrates a fourth example of multiple connections according to an embodiment of the disclosure of the present specification.

[0021] Figures 12a and 12b illustrate a first example of the first disclosure of the present specification.

[0022] Figures 13a and 13b show a second example of the first disclosure of the present specification.

[0023] Figures 14a and 14b show a third example of the first disclosure of the present specification.

[0024] Figures 15a and 15b show the fourth example of the first disclosure of the present specification.

[0025] FIG. 16 illustrates an example of a service request procedure for supporting dual steering according to one embodiment of the disclosure of the present specification.

[0026] FIG. 17 illustrates an example of a PDU session establishment procedure to support dual steering according to one embodiment of the disclosure of the present specification.

[0027] FIG. 18 illustrates an NG-based handover procedure for supporting dual steering according to one embodiment of the disclosure of the present specification.

[0028] FIG. 19 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0029] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems. CDMA can be implemented using wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using wireless technologies such as Global System for Mobile communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data rates for GSM Evolution (EDGE). OFDMA can be implemented using wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) Long-Term Evolution (LTE) is part of E-UMTS (Evolved UMTS) that utilizes E-UTRA.3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolution of 3GPP LTE includes LTE-A (Advanced), LTE-A Pro, and / or 5G NR (New Radio).

[0030] For convenience of explanation, the implementation of this specification is primarily described in relation to a 3GPP-based wireless communication system. However, the technical features of this specification are not limited thereto. For example, the following detailed description is provided based on a mobile communication system corresponding to a 3GPP-based wireless communication system, but aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0031] For terms and technologies used in this specification that are not specifically described, reference may be made to wireless communication standard documents published prior to this specification.

[0032] As used herein, "A or B" can mean "only A," "only B," or "both A and B." Alternatively, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0033] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0034] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0035] Additionally, in this specification, “at least one of A, B and C” can mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C”.

[0036] Additionally, parentheses used herein may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in this specification is not limited to "PDCCH," and "PDCCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0037] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0038] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein may be applied to various fields requiring wireless communication and / or connectivity between devices (e.g., 5G).

[0039] Hereinafter, the present specification will be described in more detail with reference to the drawings. In the following drawings and / or description, the same reference numbers may refer to the same or corresponding hardware blocks, software blocks, and / or functional blocks, unless otherwise indicated.

[0040] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0041] The 5G usage scenario shown in FIG. 1 is only an example, and the technical features of this specification can be applied to other 5G usage scenarios not shown in FIG. 1.

[0042] The three main requirement categories for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC).

[0043] Referring to FIG. 1, a communication system (1) includes wireless devices (100a to 100f), a base station (BS; 200), and a network (300). FIG. 1 illustrates a 5G network as an example of a network of the communication system (1), but the implementation of the present disclosure is not limited to a 5G system and can be applied to future communication systems beyond the 5G system.

[0044] The base station (200) and the network (300) may be implemented as wireless devices, and a particular wireless device may operate as a base station / network node in relation to other wireless devices.

[0045] The wireless devices (100a to 100f) represent devices that perform communication using Radio Access Technology (RAT) (e.g., 5G NR or LTE) and may also be referred to as communication / wireless / 5G devices. The wireless devices (100a to 100f) may include, but are not limited to, a robot (100a), a vehicle (100b-1 and 100b-2), an extended reality (XR) device (100c), a portable device (100d), a home appliance (100e), an Internet-of-Things (IoT) device (100f), and an artificial intelligence (AI) device / server (400). For example, the vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. The vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of HMD (Head-Mounted Device) and HUD (Head-Up Display) mounted on vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signs, vehicles, robots, etc. Portable devices may include smartphones, smart pads, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0046] In this specification, wireless devices (100a to 100f) may be referred to as user equipment (UE). The UE may include, for example, a mobile phone, a smartphone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an 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 weather / environmental device, a 5G service-related device, or a 4th industrial revolution-related device.

[0047] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a network after 5G. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station (200) / network (300). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Additionally, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0048] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) and / or between wireless devices (100a to 100f) and a base station (200) and / or between base stations (200). Here, the wireless communication / connection can be established through various RATs (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or, D2D (Device-To-Device) communication), and base station-to-base station communication (150c) (e.g., relay, IAB (Integrated Access and Backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless devices (100a to 100f) and the base station (200) can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of the various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of the present specification.

[0049] NR supports multiple numerologies, or subcarrier spacings (SCS), to support diverse 5G services. For example, an SCS of 15 kHz supports wide areas in traditional cellular bands; an SCS of 30 kHz / 60 kHz supports dense urban areas, lower latency, and wider carrier bandwidth; and an SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0050] The NR frequency band can be defined by two types of frequency ranges (FR1 and FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 can mean the "sub 6 GHz range," and FR2 can mean the "above 6 GHz range," which can be called millimeter wave (mmW).

[0051] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0052] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band from 410 MHz to 7125 MHz, as shown in Table 2 below. That is, FR1 may include frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency bands above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include unlicensed bands. Unlicensed bands can be used for various purposes, such as for communications for vehicles (e.g., autonomous driving).

[0053] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0054] Here, the wireless communication technology implemented in the wireless device of the present specification may include not only LTE, NR, and 6G, but also Narrowband IoT (NB-IoT) for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced MTC). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (Non-Bandwidth Limited), 5) LTE-MTC, 6) LTE MTC, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification can include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PANs (Personal Area Networks) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0055] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0056] In FIG. 2, the first wireless device (100) and / or the second wireless device (200) may be implemented in various forms depending on the use case / service. For example, {the first wireless device (100) and the second wireless device (200)} may correspond to at least one of {the wireless devices (100a to 100f) and the base station (200)}, {the wireless devices (100a to 100f) and the wireless devices (100a to 100f)}, and / or {the base station (200) and the base station (200)} of FIG. 1. The first wireless device (100) and / or the second wireless device (200) may be configured by various components, devices / parts, and / or modules.

[0057] The first wireless device (100) may include at least one transceiver, such as a transceiver (106), at least one processing chip, such as a processing chip (101), and / or one or more antennas (108).

[0058] The processing chip (101) may include at least one processor, such as a processor (102), and at least one memory, such as a memory (104). Additionally and / or alternatively, the memory (104) may be located external to the processing chip (101).

[0059] The processor (102) may control the memory (104) and / or the transceiver (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor (102) may process information in the memory (104) to generate first information / signal and transmit a wireless signal including the first information / signal via the transceiver (106). The processor (102) may receive a wireless signal including second information / signal via the transceiver (106) and store information obtained by processing the second information / signal in the memory (104).

[0060] A memory (104) may be operatively connected to the processor (102). The memory (104) may store various types of information and / or instructions. The memory (104) may store firmware and / or software code (105) that implements code, instructions and / or sets of instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may implement instructions that, when executed by the processor (102), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more protocols. For example, the firmware and / or software code (105) may control the processor (102) to perform one or more air interface protocol layers.

[0061] Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). Each transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present specification, the first wireless device (100) may represent a communication modem / circuit / chip.

[0062] The second wireless device (200) may include at least one transceiver, such as a transceiver (206), at least one processing chip, such as a processing chip (201), and / or one or more antennas (208).

[0063] The processing chip (201) may include at least one processor, such as a processor (202), and at least one memory, such as a memory (204). Additionally and / or alternatively, the memory (204) may be located external to the processing chip (201).

[0064] The processor (202) may control the memory (204) and / or the transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein. For example, the processor (202) may process information in the memory (204) to generate third information / signal and transmit a wireless signal including the third information / signal via the transceiver (206). The processor (202) may receive a wireless signal including fourth information / signal via the transceiver (206) and store information obtained by processing the fourth information / signal in the memory (204).

[0065] A memory (204) may be operatively connected to the processor (202). The memory (204) may store various types of information and / or instructions. The memory (204) may store firmware and / or software code (205) that implements code, instructions and / or sets of instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may implement instructions that, when executed by the processor (202), perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed herein. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more protocols. For example, the firmware and / or software code (205) may control the processor (202) to perform one or more air interface protocol layers.

[0066] Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). Each transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with the RF unit. In the present specification, the second wireless device (200) may represent a communication modem / circuit / chip.

[0067] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a Media Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Resource Control (RRC) layer, and a Service Data Adaptation Protocol (SDAP) layer). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs), one or more Service Data Units (SDUs), messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0068] The one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, and / or a microcomputer. The one or more processors (102, 202) may be implemented by hardware, firmware, software, and / or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), and / or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors (102, 202). For example, the one or more processors (102, 202) may be configured by a set of a communication control processor, an Application Processor (AP), an Electronic Control Unit (ECU), a Central Processing Unit (CPU), a Graphic Processing Unit (GPU), and a Memory Control Processor. One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions and / or commands. The one or more memories (104, 204) may be configured as random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), erasable programmable ROM (EPROM), flash memory, volatile memory, nonvolatile memory, hard drive, register, cache memory, computer readable storage media and / or combinations thereof.One or more memories (104, 204) may be located internally and / or externally to one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0069] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, wireless signals, etc., to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, wireless signals, etc. from one or more other devices.

[0070] One or more transceivers (106, 206) may be coupled to one or more antennas (108, 208). Additionally and / or alternatively, one or more transceivers (106, 206) may include one or more antennas (108, 208). One or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein via one or more antennas (108, 208). In the present disclosure, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0071] One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or a filter. For example, one or more transceivers (106, 206) may up-convert an OFDM baseband signal to an OFDM signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202) and transmit the up-converted OFDM signal at a carrier frequency. One or more transceivers (106, 206) may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal via an (analog) oscillator and / or filter under the control of one or more processors (102, 202).

[0072] Although not illustrated in FIG. 2, the wireless device (100, 200) may further include additional components. The additional components (140) may be configured in various ways depending on the type of the wireless device (100, 200). For example, the additional components (140) may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a driving device, and a computing device. The additional components (140) may be connected to one or more processors (102, 202) via various technologies, such as a wired or wireless connection.

[0073] In the implementation of this specification, a UE can operate as a transmitter in the uplink and as a receiver in the downlink. In the implementation of this specification, a base station can operate as a receiver in the UL and as a transmitter in the DL. For the sake of convenience of description, it is mainly assumed below that the first wireless device (100) operates as a UE and the second wireless device (200) operates as a base station. For example, a processor (102) connected to, mounted on, or released in the first wireless device (100) can be configured to perform UE operations according to the implementation of this specification or to control a transceiver (106) to perform UE operations according to the implementation of this specification. A processor (202) connected to, mounted on, or released in the second wireless device (200) can be configured to perform base station operations according to the implementation of this specification or to control a transceiver (206) to perform base station operations according to the implementation of this specification.

[0074] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0075] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0076] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0077] The UE (100) includes a processor (102), memory (104), a transceiver (106), one or more antennas (108), a power management module (141), a battery (142), a display (143), a keypad (144), a SIM (Subscriber Identification Module) card (145), a speaker (146), and a microphone (147).

[0078] The processor (102) may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. The processor (102) may be configured to control one or more other components of the UE (100) to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed herein. A layer of a radio interface protocol may be implemented in the processor (102). The processor (102) may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor (102) may be an application processor. The processor (102) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator). An example of the processor (102) is the SNAPDRAGON manufactured by Qualcomm®. TM Series processors, EXYNOS made by Samsung® TM Series processors, A-series processors made by Apple®, HELIO made by MediaTek® TM ATOM series processors made by Intel® TM It can be found in the series processors or the corresponding next-generation processors.

[0079] Memory (104) is operatively coupled to the processor (102) and stores various information for operating the processor (102). Memory (104) may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When the implementation is implemented in software, the techniques described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed herein. The modules may be stored in memory (104) and executed by the processor (102). Memory (104) may be implemented within the processor (102) or external to the processor (102), in which case it may be communicatively coupled to the processor (102) via various methods known in the art.

[0080] A transceiver (106) is operably coupled to the processor (102) and transmits and / or receives a radio signal. The transceiver (106) includes a transmitter and a receiver. The transceiver (106) may include a baseband circuit for processing a radio frequency signal. The transceiver (106) controls one or more antennas (108) to transmit and / or receive a radio signal.

[0081] The power management module (141) manages the power of the processor (102) and / or the transceiver (106). The battery (142) supplies power to the power management module (141).

[0082] The display (143) outputs the results processed by the processor (102). The keypad (144) receives input to be used by the processor (102). The keypad (144) can be displayed on the display (143).

[0083] A SIM card (145) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and is used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0084] The speaker (146) outputs sound-related results processed by the processor (102). The microphone (147) receives sound-related input to be used by the processor (102).

[0085] Figure 4 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0086] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0087] - AUSF (Authentication Server Function)

[0088] -AMF (Access and Mobility Management Function)

[0089] - DN (Data Network), for example, operator services, Internet access, or third-party services.

[0090] - USDF (Unstructured Data Storage Function)

[0091] - NEF (Network Exposure Function)

[0092] - I-NEF (Intermediate NEF)

[0093] - NRF (Network Repository Function)

[0094] - NSSF (Network Slice Selection Function)

[0095] - PCF (Policy Control Function)

[0096] - SMF (Session Management Function)

[0097] - UDM (Unified Data Management)

[0098] - UDR (Unified Data Repository)

[0099] - UPF (User Plane Function)

[0100] - UCMF (UE radio Capability Management Function)

[0101] - AF (Application Function)

[0102] - UE (User Equipment)

[0103] - (R)AN ((Radio) Access Network)

[0104] - 5G-EIR (5G-Equipment Identity Register)

[0105] - NWDAF (Network Data Analytics Function)

[0106] - CHF (CHarging Function)

[0107] 또한, 다음과 같은 네트워크 기능이 고려될 수 있다.

[0108] - N3IWF (Non-3GPP InterWorking Function)

[0109] - TNGF (Trusted Non-3GPP Gateway Function)

[0110] - W-AGF (Wireline Access Gateway Function)

[0111] Figure 4 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0112] For clarity of the point-to-point diagram in Figure 4, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0113] For clarity, the connection between UDR and other NFs (e.g., PCF) is not shown in Fig. 4. For clarity, the connection between NWDAF and other NFs (e.g., PCF) is not shown in Fig. 4.

[0114] The 5G system architecture includes the following benchmarks:

[0115] - N1: Reference point between UE and AMF.

[0116] - N2: Reference point between (R)AN and AMF.

[0117] - N3: Reference point between (R)AN and UPF.

[0118] - N4: Reference point between SMF and UPF.

[0119] - N6: Reference point between UPF and data network.

[0120] - N9: Reference point between two UPFs.

[0121] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0122] - N5: Reference point between PCF and AF.

[0123] - N7: Reference point between SMF and PCF.

[0124] - N8: Reference point between UDM and AMF.

[0125] - N10: Reference point between UDM and SMF.

[0126] - N11: Reference point between AMF and SMF.

[0127] - N12: Reference point between AMF and AUSF.

[0128] - N13: Reference point between UDM and AUSF.

[0129] - N14: Reference point between two AMFs.

[0130] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0131] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0132] - N22: Reference point between AMF and NSSF.

[0133] In some cases, two NFs may need to be interconnected to serve a UE.

[0134] Describes the registration procedure. See section 4.2.2.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0135] Figures 5 and 6 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0136] A UE must register with the network to receive services, enable mobility tracking, and enable reachability. The UE initiates the registration process using one of the following registration types:

[0137] - Initial registration for 5GS; or

[0138] - mobility registration update; or

[0139] - Periodic registration update; or

[0140] - Emergency registration

[0141] The general registration procedures of Figures 5 and 6 apply to all registration procedures described above, but periodic registration updates do not need to include all parameters used in other registration procedures.

[0142] The general registration procedures of Figures 5 and 6 can also be used to register a UE for a 3GPP connection when it is already registered for a non-3GPP connection, and vice versa. Registering a UE for a 3GPP connection when it is already registered for a non-3GPP connection scenario may require an AMF change.

[0143] First, the procedure of Fig. 5 is described.

[0144] (1) Step 1: The UE transmits a Registration Request message to the (R)AN. The Registration Request message corresponds to an AN message.

[0145] The registration request message may include AN parameters. For NG-RAN, the AN parameters include, for example, the 5G SAE temporary mobile subscriber identity (5G-S-TMSI) or globally unique AMF ID (GUAMI), the selected public land mobile network (PLMN) ID (or PLMN ID and network identifier (NID)), and the requested network slice selection assistance information (NSSAI). The AN parameters also include an establishment cause. The establishment cause provides the reason for requesting establishment of an RRC connection. Whether and how the UE includes the requested NSSAI as part of the AN parameters depends on the value of the access stratum connection establishment NSSAI inclusion mode parameter.

[0146] A registration request message may include a registration type. The registration type indicates whether the UE wants to perform an initial registration (i.e., the UE is in RM-DEREGISTERED state), or a mobility registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because the UE moves, or the UE wants to update its capabilities or protocol parameters, or because the UE requests a change in the set of network slices it is allowed to use), or a periodic registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because the periodic registration update timer has expired), or an emergency registration (i.e., the UE is in restricted service state).

[0147] When a UE performs initial registration, the UE indicates its UE ID in the registration request message, listed in decreasing priority order.

[0148] i) If the UE has a valid evolved packet system (EPS) globally unique temporary identifier (GUTI), 5G-GUTI mapped from the EPS GUTI;

[0149] ii) Native 5G-GUTI (if available) allocated by the PLMN in which the UE is attempting to register;

[0150] iii) Native 5G-GUTI allocated by a PLMN equivalent to the PLMN in which the UE is attempting to register;

[0151] iv) Native 5G-GUTI allocated by another PLMN (if available);

[0152] v) Otherwise, the UE includes a subscriber concealed identifier (SUCI) in the registration request message.

[0153] If a UE performing initial registration has both a valid EPS GUTI and a native 5G-GUTI, the UE also indicates the native 5G-GUTI as an additional GUTI. If more than one native 5G-GUTI is available, the UE selects a 5G-GUTI from items (ii)-(iv) in decreasing priority order in the list above.

[0154] When the UE performs initial registration with native 5G-GUTI, the UE indicates the relevant GUAMI information in the AN parameters. When the UE performs initial registration with SUCI, the UE does not indicate the GUAMI information in the AN parameters.

[0155] For emergency registration, if the UE does not have a valid 5G-GUTI, the SUCI is included. If the UE does not have a subscriber permanent identifier (SUPI) and does not have a valid 5G-GUTI, the PEI (Permanent Equipment Identifier) ​​is included. Otherwise, the 5G-GUTI is included, indicating the last serving AMF.

[0156] The registration request message may also include security parameters, PDU session status, etc. Security parameters are used for authentication and integrity protection. The PDU session status indicates a previously established PDU session in the UE. When the UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the PDU session status indicates the PDU session currently established in the PLMN in the UE.

[0157] (2) Step 2: (R)AN selects AMF.

[0158] If 5G-S-TMSI or GUAMI is not included, or if 5G-S-TMSI or GUAMI does not indicate a valid AMF, the (R)AN selects an AMF based on the (R)AT and the requested NSSAI, if available.

[0159] When the UE is in CM-CONNECTED state, (R)AN can forward a registration request message to AMF based on the N2 connection of the UE.

[0160] If the (R)AN cannot select an appropriate AMF, the (R)AN performs AMF selection by forwarding a registration request message to the AMF configured in the (R)AN.

[0161] (3) Step 3: (R)AN sends a registration request message to the new AMF. The registration request message corresponds to the N2 message.

[0162] The registration request message may contain all of the information and / or part of the information contained in the registration request message received from the UE described in step 1.

[0163] The registration request message may include an N2 parameter. When NG-RAN is used, the N2 parameter includes the selected PLMN ID (or PLMN ID and NID), location information and cell ID related to the cell where the UE is camping, and a UE context request indicating that a UE context including security information should be established in the NG-RAN. When NG-RAN is used, the N2 parameter also includes an establishment cause.

[0164] If the registration type indicated by the UE is periodic registration update, steps 4-19 described below may be omitted.

[0165] (4) Step 4: If the UE's 5G-GUTI is included in the registration request message and the serving AMF has changed since the last registration procedure, the new AMF may invoke the Namf_Communication_UEContextTransfer service operation to the previous AMF, including the full registration request non-access stratum (NAS) message to request the UE's SUPI and UE context.

[0166] (5) Step 5: The old AMF can respond to the new AMF for the Namf_Communication_UEContextTransfer call including the UE's SUPI and UE context.

[0167] (6) Step 6: If SUCI is not provided by the UE or not retrieved from the previous AMF, the new AMF may initiate an ID request procedure by sending an Identity Request message to request SUCI from the UE.

[0168] (7) Step 7: The UE may respond with an Identity Response message including the SUCI. The UE derives the SUCI using the provided public key of the home PLMN (HPLMN).

[0169] (8) Step 8: The new AMF may decide to initiate UE authentication by calling the AUSF. In this case, the new AMF selects the AUSF based on SUPI or SUCI.

[0170] (9) Step 9: Authentication / security can be established by UE, new AMF, AUSF and / or UDM.

[0171] (10) Step 10: If the AMF has changed, the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation to notify the old AMF that the UE registration with the new AMF is complete. If the authentication / security procedure fails, the registration is rejected and the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation with a reject indication reason code to the old AMF. The old AMF may continue as if the UE context transfer service operation was not received.

[0172] (11) Step 11: If the PEI was not provided by the UE or was not retrieved from the previous AMF, the new AMF may initiate the ID request procedure by sending an Identity Request message to the UE to retrieve the PEI. The PEI is transmitted encrypted, except when the UE performs emergency registration and cannot be authenticated.

[0173] (12) Step 12: Optionally, the new AMF can initiate ME ID checking by calling the N5g-eir_EquipmentIdentityCheck_Get service operation.

[0174] Now, the procedure of Fig. 6 following the procedure of Fig. 5 is described.

[0175] (13) Step 13: When step 14 below is performed, the new AMF can select a UDM based on SUPI, and the UDM can select a UDR instance.

[0176] (14) Step 14: New AMFs can be registered with UDM.

[0177] (15) Step 15: New AMF can select PCF.

[0178] (16) Step 16: The new AMF can optionally perform AM policy association establishment / modification.

[0179] (17) Step 17: The new AMF can send update / release SM context messages (e.g., Nsmf_PDUSession_UpdateSMContext and / or Nsmf_PDUSession_ReleaseSMContext) to the SMF.

[0180] (18) Step 18: If the new AMF and the old AMF are in the same PLMN, the new AMF may send a UE context modification request to the N3IWF / TNGF / W-AGF.

[0181] (19) Step 19: N3IWF / TNGF / W-AGF may send a UE context modification response to the new AMF.

[0182] (20) Step 20: After the new AMF receives the response message from N3IWF / TNGF / W-AGF in step 19, the new AMF can register with UDM.

[0183] (21) Step 21: The new AMF sends a Registration Accept message to the UE.

[0184] The new AMF sends the UE a Registration Accept message indicating that the registration request has been accepted. If the new AMF allocates a new 5G-GUTI, it includes the 5G-GUTI. If the UE is already in the RM-REGISTERED state through another connection to the same PLMN, the UE uses the 5G-GUTI received in the Registration Accept message for both registrations. If the Registration Accept message does not include a 5G-GUTI, the UE uses the 5G-GUTI assigned to the existing registration for the new registration. If the new AMF allocates a new registration area, it sends the registration area to the UE in the Registration Accept message. If the Registration Accept message does not include a registration area, the UE considers the previous registration area to be valid. Mobility Restrictions are included if mobility restrictions apply to the UE and the registration type is not emergency registration. The new AMF indicates the PDU sessions established for the UE in the PDU Session State. The UE locally removes internal resources associated with PDU sessions that are not marked as established in the received PDU Session State. When a UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the UE locally removes internal resources associated with PDU sessions in the current PLMN that are not marked as established in the received PDU session status. If PDU session status information is present in the Registration Accept message, the new AMF indicates the PDU session status to the UE.

[0185] The Allowed NSSAI provided in the Registration Accept message is valid for the registration area and applies to all PLMNs that have a tracking area included in the registration area. The Mapping of Allowed NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Allowed NSSAIs. The Mapping of Configured NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Configured NSSAI for the serving PLMN.

[0186] Additionally, optionally, the new AMF performs UE policy association establishment.

[0187] (22) Step 22: If the UE successfully updates itself, it can send a Registration Complete message to the new AMF.

[0188] The UE may send a registration complete message to the new AMF to confirm that a new 5G-GUTI has been allocated.

[0189] (23) Step 23: In case of registration via 3GPP connection, if the new AMF does not release the signaling connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN. In case of registration via non-3GPP connection, if the UE is in CM-CONTENED state on the 3GPP connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN.

[0190] (24) Step 24: AMF can perform information updates on UDM.

[0191] (25) Step 25: The UE may execute a network slice-specific authentication and authorization (NSSAA) procedure.

[0192] Describes the PDU session establishment procedure. See Section 4.3.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0193] Figures 7 and 8 illustrate examples of a PDU session establishment procedure to which the implementation of the present specification applies.

[0194] Establishing a PDU session may involve:

[0195] - UE-initiated PDU session establishment procedure

[0196] - PDU session handover between 3GPP and non-3GPP initiated by UE

[0197] - PDU session handover from UE-initiated EPS to 5GS.

[0198] - Network-triggered PDU session establishment procedure

[0199] A PDU session may be associated with either (a) a single connection type at a given time, i.e., either a 3GPP connection or a non-3GPP connection, or (b) multiple connection types simultaneously, i.e., one 3GPP connection and one non-3GPP connection. A PDU session associated with multiple connection types is called a multi-access (MA) PDU session and may be requested by an access traffic steering, switching, splitting (ATSS) capable UE.

[0200] Figures 7 and 8 specify a procedure for establishing a PDU session associated with a single connection type at a given time.

[0201] In the procedures shown in Figures 7 and 8, it is assumed that the UE is already registered with the AMF, so unless the UE is emergency registered, the AMF has already retrieved the user subscription data from the UDM.

[0202] First, the procedure of Fig. 7 is explained.

[0203] (1) Step 1: To establish a new PDU session, the UE generates a new PDU session ID.

[0204] The UE initiates the PDU session establishment procedure requested by the UE by sending an NAS message containing a PDU session establishment request message within the N1 SM container. The PDU session establishment request message includes the PDU session ID, the requested PDU session type, the requested session and service continuity (SSC) mode, 5G SM capabilities, Protocol Configuration Options (PCO), the SM PDU DN Request Container, and the UE Integrity Protection Maximum Data Rate.

[0205] If the PDU session establishment is a request to establish a new PDU session, the request type is "Initial Request." If the request refers to an existing PDU session switching between a 3GPP connection and a non-3GPP connection, or a PDU session handover from an existing packet data network (PDN) connection in the EPC, the request type is "Existing PDU Session." If the PDU session establishment is a request to establish a PDU session for emergency services, the request type is "Emergency Request." If the request refers to an existing PDU session for emergency services switching between a 3GPP connection and a non-3GPP connection, or a PDU session handover from an existing PDN connection for emergency services in the EPC, the request type is "Existing Emergency PDU Session."

[0206] The UE includes the S-NSSAI from the allowed NSSAI of the current connection type. If a mapping of allowed NSSAIs (Mapping of Allowed NSSAIs) is provided to the UE, the UE provides both the S-NSSAI of the VPLMN (visited VPLMN) from the allowed NSSAIs and the corresponding S-NSSAI of the HPLMN from the mapping of allowed NSSAIs.

[0207] (2) Step 2: AMF selects an SMF. If the request type indicates "Initial Request" or the request is due to a handover from an EPS or other non-3GPP connection provided by an AMF, AMF stores the connection type of the PDU session as well as the association of S-NSSAI(s), data network name (DNN), PDU session ID, and SMF ID.

[0208] If the request type is "Initial Request" and the message also contains a previous PDU session ID representing an existing PDU session, AMF selects an SMF and stores the association of the new PDU session ID, S-NSAI(s), and the selected SMF ID.

[0209] If the request type indicates "Existing PDU Session," AMF selects an SMF based on the SMF-ID received from the UDM. AMF updates the stored connection type for the PDU session.

[0210] If the request type indicates "Existing PDU Session", which refers to an existing PDU session moving between a 3GPP connection and a non-3GPP connection, and if the serving PLMN S-NSSAI of the PDU session is in the allowed NSSAI of the target connection type, the PDU session establishment procedure may be performed in the following cases:

[0211] - When the SMF ID and AMF corresponding to the PDU session ID belong to the same PLMN;

[0212] - If the SMF ID corresponding to the PDU session ID belongs to HPLMN;

[0213] Otherwise, AMF rejects the PDU session establishment request with an appropriate rejection cause.

[0214] AMF rejects requests from emergency-registered UEs whose request type does not indicate "Emergency Request" or "Existing Emergency PDU Session".

[0215] (3) Step 3: If the AMF is not associated with an SMF for the PDU session ID provided by the UE (e.g., when the request type indicates "Initial Request"), the AMF invokes the Create SM Context request procedure (e.g., Nsmf_PDUSession_CreateSMContext Request). If the AMF is already associated with an SMF for the PDU session ID provided by the UE (e.g., when the request type indicates "Existing PDU Session"), the AMF invokes the Update SM Context request procedure (e.g., Nsmf_PDUSession_UpdateSMContext Request).

[0216] The AMF transmits the S-NSSAI of the serving PLMN to the SMF from the allowed NSSAI. For a roaming scenario of local breakout (LBO), the AMF also transmits the corresponding S-NSSAI of the HPLMN to the SMF from the mapping of the allowed NSSAI.

[0217] The AMF ID is the UE's GUAMI, which uniquely identifies the AMF serving the UE. The AMF passes the PDU session ID along with the N1 SM container containing the PDU session establishment request message received from the UE. The GPSI (generic public subscription identifier) ​​is included if available to the AMF.

[0218] If a UE in limited service state is registered for emergency services without providing SUPI, the AMF provides PEI instead of SUPI. If a UE in limited service state is registered for emergency services while providing SUPI but is not authenticated, the AMF indicates that the SUPI is not authenticated. If the SMF does not receive a SUPI for the UE or if the AMF indicates that the SUPI is not authenticated, the UE is considered unauthenticated.

[0219] AMF can include a PCF ID in Nsmf_PDUSession_CreateSMContext. This PCFID identifies the home PCF (H-PCF) in non-roaming cases and the visited PCF (V-PCF) in LBO roaming cases.

[0220] (4) Step 4: If the session management subscription data for the S-NSSAI of the corresponding SUPI, DNN, or HPLMN is not available, the SMF can retrieve the session management subscription data from the UDM and be notified when the subscription data is modified.

[0221] (5) Step 5: SMF sends a create SM context response message (e.g., Nsmf_PDUSession_CreateSMContext Response) or an update SM context response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to AMF according to the request received in step 3.

[0222] If SMF receives the Nsmf_PDUSession_CreateSMContext Request in step 3 and can process the PDU session establishment request, SMF creates an SM context and responds to AMF by providing the SM context ID.

[0223] If the SMF decides not to accept the PDU session establishment, the SMF rejects the UE request by sending a NAS SM signal including the relevant SM rejection cause by responding to the AMF with an Nsmf_PDUSession_CreateSMContext Response. The SMF also indicates to the AMF that the PDU session ID is considered released and the SMF proceeds to step 20 below, aborting the PDU session establishment procedure.

[0224] (6) Step 6: Optional secondary authentication / authorization may be performed.

[0225] (7a) Step 7a: When dynamic policy and charging control (PCC) is used in a PDU session, the SMF can perform PCF selection.

[0226] (7b) Step 7b: SMF performs the SM policy association establishment procedure to establish a PCF and SM policy association, and obtains the basic PCC rules for the PDU session.

[0227] (8) Step 8: SMF selects one or more UPFs.

[0228] (9) Step 9: The SMF may provide information about the satisfied policy control request trigger conditions by performing the SM policy association modification procedure initiated by the SMF.

[0229] (10) Step 10: If the request type indicates an "Initial Request," the SMF may initiate the N4 Session Establishment procedure with the selected UPF. Otherwise, the SMF may initiate the N4 Session Modification procedure with the selected UPF.

[0230] In step 10a, the SMF can send an N4 session establishment / modification request to the UPF, providing packet detection, enforcement, and reporting rules to be installed in the UPF for the PDU session. In step 10b, the UPF can confirm by sending an N4 session establishment / modification response.

[0231] (11) Step 11: SMF sends an N1N2 message transfer message (e.g. Namf_Communication_N1N2 Message Transfer) to AMF.

[0232] The N1N2 Message Forwarding message may contain N2 SM information. The N2 SM information carries the following information that the AMF will forward to the (R)AN:

[0233] - CN Tunnel Info: Corresponds to the core network address of the N3 tunnel corresponding to the PDU session;

[0234] - QFI (QoS flow ID) corresponding to one or more QoS (quality of service) profiles;

[0235] - PDU Session ID: Indicates to the UE the association between RAN resources and a PDU session for the UE;

[0236] - S-NSSAI with value for serving PLMN (i.e. HPLMN S-NSSAI, or VPLMN S-NSSAI in case of LBO roaming);

[0237] - User plane security enforcement information determined by SMF;

[0238] - UE integrity protection maximum data rate received in PDU Session Establishment Request message: if integrity protection is indicated as "Preferred" or "Required" in the user plane security enforcement information.

[0239] - RSN (redundancy sequence number) parameter

[0240] The N1N2 message transfer message may include an N1 SM container. The N1 SM container includes a PDU Session Establishment Accept message that the AMF will provide to the UE. The PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI. For the LBO roaming scenario, the PDU Session Establishment Accept message includes the S-NSSAI from the allowed NSSAI for the VPLMN, and also includes the corresponding S-NSSAI of the HPLMN from the mapping of the allowed NSSAI received by the SMF in step 3.

[0241] Multiple QoS rules, QoS flow levels, and QoS parameters may be included in the PDU session establishment accept message and N2 SM information within the N1 SM container, if required, for QoS flows associated with QoS rules and QoS profiles.

[0242] If the PDU session establishment fails between steps 5 and 11, the N1N2 message forwarding message contains an N1 SM container containing a PDU session establishment rejection message, but does not contain N2 SM information. The (R)AN sends an NAS message containing a PDU session establishment rejection message to the UE. In this case, steps 12-17 below are omitted.

[0243] (12) Step 12: AMF sends a NAS message containing the PDU Session ID and PDU Session Establishment Accept message destined for the UE and the N2 SM information received from SMF to (R)AN within an N2 PDU Session Request message.

[0244] (13) Step 13: The (R)AN may perform AN-specific signaling exchanges with the UE related to the information received from the SMF. For example, in the case of the NG-RAN, the UE may perform an RRC connection reconfiguration with the UE to set up the necessary NG-RAN resources related to the QoS rules for the PDU session request received in step 12.

[0245] (R)AN forwards the NAS message (PDU Session ID, N1 SM container (PDU Session Establishment Accept message)) received in step 12 to the UE. (R)AN provides the NAS message to the UE only if the AN-specific signaling exchange with the UE includes (R)AN resource additions related to the received N2 command.

[0246] If N2 SM information is not included in step 11, steps 14-16b and 17 below are omitted.

[0247] Now, the procedure of Fig. 8 following the procedure of Fig. 7 is described.

[0248] (14) Step 14: (R)AN sends an N2 PDU Session Response message to AMF. The N2 PDU Session Response message may include PDU Session ID, cause, N2 SM information (PDU Session ID, AN tunnel information, accepted / rejected QFI list, user plane enforcement policy notification), etc.

[0249] (15) Step 15: AMF sends an update SM context request message (e.g., Nsmf_PDUSession_UpdateSMContext Request) to SMF. AMF forwards the N2 SM information received from (R)AN to SMF.

[0250] (16a) Step S16a: SMF initiates the N4 session modification procedure with UPF. SMF provides AN tunnel information and corresponding forwarding rules to UPF.

[0251] (16b) Step S16b: UPF provides an N4 session modification response to SMF.

[0252] After this step, the UPF can forward any DL packets that may have been buffered for this PDU session to the UE.

[0253] (16c) Step 16c: If the SMF is not yet registered for this PDU session, the SMF may register with the UDM for the given PDU session.

[0254] (17) Step 17: SMF sends an update SM context response message (e.g., Nsmf_PDUSession_UpdateSMContext Response) to AMF.

[0255] After this step, AMF forwards the relevant events to which SMF subscribes.

[0256] (18) Step 18: At any time during the procedure after Step 5, if the PDU session establishment is not successful, the SMF can notify the AMF by calling Nsmf_PDUSession_SMContextStatusNotify (release). The SMF can also release the created N4 session, the PDU session address (e.g., IP address) if assigned, and possibly the association with the PCF. In this case, Step 19 below is omitted.

[0257] (19) Step 19: For PDU session type IPv6 or IPv4v6, SMF may generate and send an IPv6 Router Advertisement to the UE.

[0258] (20) Step 20: SMF can perform SM policy association modification initiated by SMF.

[0259] (21) Step 21: If the PDU session establishment fails after step 4, the SMF may unsubscribe for modification of session management subscription data if the SMF no longer processes the UE's PDU session.

[0260] Network Slice

[0261] Below, we explain network slicing to be introduced in next-generation mobile communications.

[0262] Next-generation mobile communications introduce the concept of network slicing to provide diverse services through a single network. Here, a network slicing refers to a combination of network nodes with the functions necessary to provide a specific service. The network nodes that make up a slice instance can be either hardware-independent or logically independent.

[0263] Each slice instance can be composed of any combination of nodes required to form the entire network. In this case, a single slice instance can provide services to a UE independently.

[0264] Alternatively, a slice instance may be composed of a combination of nodes within the network. In this case, the slice instance may not provide services to the UE independently, but may instead collaborate with other existing network nodes to provide services to the UE. Furthermore, multiple slice instances may collaborate to provide services to the UE.

[0265] Slice instances differ from dedicated core networks in that the entire network, including the core network (CN) nodes and the RAN, can be separated. Furthermore, slice instances differ from dedicated core networks in that network nodes can be logically separated.

[0266] Note that for network slices, quotas can be used.

[0267] For example, a quota associated with a network slice may include a quota for a maximum number of UEs. The quota for the maximum number of UEs may refer to the maximum number of terminals that can simultaneously use the network slice. For example, each network slice information may include quota information for a maximum number of UEs (e.g., 10, 1,000,000, etc.).

[0268] For example, a quota associated with a network slice may include a quota for the maximum number of PDU sessions. The quota for the maximum number of PDU sessions may refer to the maximum number of concurrent PDU sessions supported by the network slice. For example, the maximum number of concurrent PDU sessions supported by the network slice may refer to the maximum number of PDU sessions that can be simultaneously established within a network slice associated with a Data Network Name (DNN) defined by the S-NSSAI.

[0269] In 5G mobile communications, network slice quota event notifications may be supported within a network slice. For example, event notifications regarding quotas related to a network slice may be supported. For example, an AF may request an event notification regarding quotas related to a network slice from 5GS. Then, the AF may receive quota notifications for attributes related to the network slice from 5GS. For example, the 5GS may notify the AF whether the quota for a specific attribute has reached a specified threshold. Then, the AF may influence 5GS routing decisions.

[0270] Figure 9 is an example diagram showing an example of an architecture for implementing the concept of network slicing.

[0271] As can be seen from Figure 9, a core network (CN) can be divided into multiple slice instances. Each slice instance can include one or more CP functional nodes and UP functional nodes.

[0272] Each UE can use a network slice instance suitable for its service through the RAN.

[0273] Unlike the example illustrated in FIG. 9, each slice instance may share one or more of the CP function nodes and UP function nodes with other slice instances. This is described below with reference to FIG. 10.

[0274] Figure 10 is an example diagram showing another example of an architecture for implementing the concept of network slicing.

[0275] Referring to FIG. 10, multiple UP function nodes are clustered, and similarly multiple CP function nodes are clustered.

[0276] And, referring to FIG. 10, slice instance #1 (or referred to as instance #1) within the core network includes a first cluster of UP functional nodes. And, the slice instance #1 shares a cluster of CP functional nodes with slice #2 (or referred to as instance #2). The slice instance #2 includes a second cluster of UP functional nodes.

[0277] The illustrated NSSF selects a slice (or instance) that can accommodate the UE's service.

[0278] The illustrated UE can use service #1 through slice instance #1 selected by the NSSF, and can also use service #2 through slice instance #2 selected by the N.

[0279] In 3GPP, a study called FS_DualSteer (Study on Upper layer traffic steering, switching, and split over dual 3GPP access - SP-220445) is being discussed. Dual Steer may include use cases and service requirements related to steering, splitting, and switching UE traffic over two 3GPP access links, for example. Specifically, the study is being conducted for the following objectives. For examples of use cases and service requirements, please refer to TR 22.841 V1.1.0 "Study on Upper layer traffic steer, switch, and split over dual 3GPP access."

[0280] Examples of Objectives related to dual steering include:

[0281] Additional use cases and potential service requirements that could benefit from UE traffic support for higher layer steering, split and switching (e.g., related to the same data session) in 5GS are studied, assuming only a single subscription to two 3GPP access links, including the following scenarios:

[0282] - Single PLMN, PLMN plus (standalone) NPN, 2 PLMNs

[0283] - Same or different 3GPP RAT (add NR or NTN, or NR, NTN, or LTE)

[0284] Note: NTN can refer to NR-based satellite access, including various orbits (e.g., GEO / MEO / LEO), which stand for Geostationary Earth Orbit (GEO), Medium Earth Orbit (MEO), and Low Earth Orbit (LEO), respectively.

[0285] For the PLMN plus PLMN / NPN scenario, the two networks can be managed by the same operator or by different operators (assuming there is a business agreement between the operators).

[0286] The study related to dual steering includes a gap analysis regarding the support of use cases identified by existing service requirements and functions, including the potential applicability of existing multi-NW requirements (e.g., TS 22.261 V19.3.0 Sections 6.1, 6.3, 6.18, 6.41).

[0287] An example use case for TR 22.841 V1.1.0 is as follows:

[0288] A use case for NTN-based dual 3GPP access is described.

[0289] By integrating two 3GPP access links simultaneously, one of which is a non-terrestrial network, the following 5G services can be provided. This could be particularly useful in remote areas where bandwidth is limited or access links are unreliable:

[0290] - Expanded mobile broadband

[0291] - Ultra Reliable Service Communication

[0292] Several service scenarios (e.g., residential users in remote areas, users on vehicles, high-speed trains, ships, or airplanes) may benefit from combining terrestrial and non-terrestrial access, or combining two types of non-terrestrial access (e.g., based on GSO and NGSO), to meet target service performance in terms of data rate and / or reliability.

[0293] In areas where service is unavailable, the bandwidth provided by terrestrial-based access (e.g., NR or LTE) may be limited at the cell edge. Adding NTN-based NG-RAN can help achieve the desired perceived data rates.

[0294] In some scenarios, such as on high-speed trains, the service area may not be completely uniform along the track, and the targeted reliability can be provided through multiple connections including NTN-based NG-RAN.

[0295] Therefore, one UE can be connected and served simultaneously by the following examples:

[0296] - One NTN-based 3GPP access and one terrestrial-based 3GPP access

[0297] - One NTN-based 3GPP access (NGSO) and another NTN-based 3GPP access (GSO).

[0298] - One NTN-based 3GPP access (NGSO) via two different satellites of the same constellation.

[0299] Dual access bonding can occur on the uplink, downlink, or both.

[0300] The same or different gNBs can serve NR cells via terrestrial access networks and satellite access networks (e.g., transparent payloads from onboard satellites).

[0301] NTN-based NG-RAN can refer to transparent payload satellites as well as regenerative payload satellites equipped with, for example, some gNB functionality.

[0302] With reference to the following Figures 11a to 11d, examples of a) to d) are described.

[0303] a) Multi-connectivity including transparent payload NTN-based NG-RAN and terrestrial NG-RAN;

[0304] The UE connects to the 5GCN simultaneously via two access points (e.g., a transparent NTN-based NG-RAN and a cellular NG-RAN). It is assumed that the NTN gateway is located in the PLMN area of ​​the cellular access network.

[0305] Referring to the examples of FIGS. 11a and 11b, an example of multi-connectivity including a transparent payload NTN-based NG-RAN and a terrestrial NG-RAN is described.

[0306] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0307] FIG. 11A is a first example of multiple connections according to one embodiment of the disclosure of the present specification.

[0308] In the example of Figure 11a, different operators may manage two PLMNs for multi-connectivity (assuming there is a business agreement between the two operators).

[0309] The example in Fig. 11a is an example of multi-connectivity including different PLMNs of transparent NTN-based NG-RAN and cellular NG-RAN.

[0310] As illustrated in Figure 11a, the UE may be connected to access based on a transparent NTN-based NG-RAN (e.g., access via a satellite, NTN gateway, gNB, or 5G CN of a first operator). Additionally, the UE may be connected to access based on a terrestrial NG-RAN connected to a 5G CN of a second operator.

[0311] Alternatively, as in the example of Figure 11b, the two accesses for multi-connectivity may be managed by the same operator.

[0312] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0313] FIG. 11b is a second example of multiple connections according to one embodiment of the disclosure of the present specification.

[0314] In the example of Figure 11b, PLMNs may be managed by the same operator. Figure 11b illustrates multi-connectivity (same PLMN) including a transparent NTN-based NG-RAN and a cellular NG-RAN.

[0315] b) Multi-connectivity including two transparent NTN-based NG-RAN accesses.

[0316] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0317] FIG. 11c is a third example of multiple connections according to one embodiment of the disclosure of the present specification.

[0318] The example in Fig. 11c shows multi-connectivity between two transparent NTN-based NG-RANs.

[0319] For example, referring to Figure 11c, multi-connectivity may include a combination of two transparent NTN-based NG-RANs (e.g., GSO and NGSO-based). This may be useful for providing service to UEs in areas where services are not available. The example of Figure 11c may utilize a relatively low-latency NGSO-based NG-RAN to support delay-sensitive traffic, and a GSO-based NG-RAN that provides additional bandwidth to meet target throughput requirements.

[0320] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0321] FIG. 11d is a fourth example of multiple connections according to one embodiment of the disclosure of the present specification.

[0322] Figure 11d shows an example of multi-connectivity between two regenerative NTN-based NG-RANs (e.g., onboard gNBs).

[0323] An example according to Fig. 11d is an example of a case where two regenerative NTN-based NG-RANs (gNB on board) are combined with an inter-satellite link via two satellites of the same constellation.

[0324] Note that Figure 11d is for illustrative purposes only. Other architectures (e.g., a split NG-RAN architecture between satellite and terrestrial) may be considered. SRI represents the satellite radio interface in Figure 11d.

[0325] Examples of preconditions relevant to this use case include:

[0326] There may be some coverage overlap between the two NG-RAN access links involved.

[0327] If the PLMN of both access links is the same, the UE connects to the 5GC that provides both access links.

[0328] 5GC knows the characteristics of each of the two access links.

[0329] When different PLMNs are used for each access link, the UE gains access to other networks through roaming agreements. Information about each access link's characteristics can be exchanged between the two networks.

[0330] The UE is in connected mode on one or more of the access links.

[0331] Slices can be deployed and managed on both access links.

[0332] An example service flow related to this use case is as follows:

[0333] A UE may establish a VoIP, video, or data service over a single 3GPP access link, but its QoS (e.g., throughput, latency, etc.) may be inadequate. If another 3GPP access link becomes available, it will be activated and combined with the first link to support the required QoS for the service.

[0334] Depending on the target QoS of the service, the user plane traffic of the connection can be intelligently steered, split and switched bidirectionally between two 3GPP NG-RAN access links based on the specific performance of each access link, such as latency, throughput, jitter and error rate.

[0335] QoS requirements for user plane traffic can be determined through specific policies associated with different data flows or different traffic types within the same data flow.

[0336] Traffic is steered / segmented between access links based on QoS requirements (e.g., latency, throughput, jitter, error rate), traffic characteristics, wireless link conditions, and the UE's mobility speed. For example, traffic requiring low latency may be best steered / segmented to the access link with the lowest latency characteristics.

[0337] In the event of a handover, temporary radio link failure, or congestion on one access link, user plane traffic can be switched to the remaining active access link. Once the radio link is re-established, user plane traffic is split and steered across the two access links based on QoS.

[0338] Data volume and other traffic statistics reported on each access link are used for billing purposes.

[0339] According to the postcondition, due to appropriate steering, splitting and switching of user plane traffic, dual NG-RAN access connections with minimal NTNs can support targeted QoS that a single access cannot support.

[0340] Examples of existing features that partially or fully encompass the use case functionality include:

[0341] This use case can leverage and extend some of the existing service requirements, including:

[0342] - Multiple access technology (see TS 22.261 V19.3.0 S6.3)

[0343] - Multi-network connection and service provision between operators (refer to TS 22.261 V19.3.0 S6.18)

[0344] -NW slice (see S6.1 of TS 22.261 V19.3.0)

[0345] - Efficient user plane (see S6.5 of TS 22.261 V19.3.0)

[0346] Potential new requirements to support the 5.5.6 use case include, for example:

[0347] Based on the use of at least one NR satellite RAT, the 5G system should be able to support simultaneous data transmissions by UEs associated with the same data session on two 3GPP 5G access networks, subject to operator policy. Based on the connection conditions (e.g., radio characteristics, mobility, congestion) of the two access networks and the UE's movement speed, the 5G system can optimally distribute user traffic between the two access networks.

[0348] When two 5G access networks are used simultaneously for the same data session, the 5G system can collect charging information for both links simultaneously.

[0349] Note that if the two 5G access networks belong to different PLMNs, single subscription and data anchoring on the HPLMN 5G CN is assumed.

[0350] Describes example use cases for UEs using terrestrial and satellite access.

[0351] Satellite access, known for its wide coverage, can improve service availability in areas with poor terrestrial access network coverage or poor radio conditions (e.g., multipath interference). When a fast-moving UE requests real-time services, such as IMS voice / video conferencing, it can simultaneously connect to the 5G system via terrestrial and satellite access, minimizing the impact of terrestrial network outages while providing continuous, stable service.

[0352] Eric is traveling to Saudi Arabia on business. He travels from Makkah to Madinah on the Haramain high-speed train, crossing 450 kilometers of desert at 300 kilometers per hour, to visit clients. He must handle urgent business via online video conferencing while on the road and resolve any issues before his arrival.

[0353] Examples of preconditions include:

[0354] TerrA's terrestrial access network offers good coverage in urban areas, suburban areas, and railway stops, but has limited coverage in rural areas and deserts between stops. SatA's satellite access network (e.g., LEO) provides nationwide coverage, and SatA can provide its own communications services. Note that TerrA is a terrestrial network operator, while SatA is a satellite network operator.

[0355] Based on this Agreement, TerrA may direct, divert or split User traffic onto the data path of the SatA network and consolidate it into TerrA's 5GC, taking into account SatA's service availability or coverage.

[0356] Eric's UE (e.g. mobile phone or wireless network card) is capable of dual 3GPP radio access, including satellite access, and is subscribed to a service-approved TerrA (PLMN NetA).

[0357] By default, only terrestrial access functions are activated.

[0358] An example of a service flow is as follows:

[0359] Eric activates the UE's satellite access feature while waiting to check in at the Macca train station.

[0360] UEs register with NetA based on their service preferences (e.g., instant chat when terrestrial access is preferred, HD TV when satellite access is preferred) over terrestrial access and satellite access networks.

[0361] After Eric connects, the online video conference begins via the terrestrial access network. During the one-hour conference, UE traffic is autonomously steered, switched, or split between the terrestrial and satellite network traffic paths with the help of TerrA's core network, and then converged on TerrA's core network to ensure uninterrupted video conference.

[0362] When the train reaches its destination, Eric disables satellite access and the UE updates its registration with NetA.

[0363] The postconditions associated with the use case are as follows: For example, the video conference is completed smoothly and without interruption. The user is unaware of any navigation, transitions, or splits during the video conference.

[0364] Examples of existing features that partially or fully encompass the use case functionality are described below.

[0365] 5G systems must support UEs with multi-radio and single-radio capabilities.

[0366] 5G systems must support the ability to steer UEs to select specific 3GPP access networks based on operator policy.

[0367] Depending on operator policy, 5G systems must be able to provide simultaneous data transmission over different access technologies (e.g., NR, E-UTRA, non-3GPP) to access one or more 3GPP services.

[0368] A UE can use two or more access technologies simultaneously. In this case, the 5G system must be able to optimally distribute user traffic by selecting one of the access technologies in use, taking into account factors such as the service, traffic characteristics, radio characteristics, and the UE's movement speed.

[0369] 5G systems must be able to support data transmission optimized for different access technologies (e.g., 3GPP, non-3GPP) for UEs simultaneously accessing the network through different connections.

[0370] Service continuity between 5G terrestrial access networks and 5G satellite access networks owned by the same operator or by different operators under contract must be supported by the 5G system.

[0371] Examples of potential new requirements needed to support use cases include:

[0372] For example, a 5G system should support a mechanism to coordinate user traffic of a UE between different 3GPP access networks and the core network for a UE using dual 3GPP access, taking into account service preferences, traffic characteristics, radio characteristics, QoS, etc. For example, a 5G system should support seamless service continuity by switching and splitting user traffic paths between different 3GPP access networks and the core network for a UE using dual 3GPP access (e.g., NR and satellite access) based on network availability, service preferences, etc.

[0373] Looking at the above use cases, services can be provided to the UE through two 3GPP accesses (or 3GPP access links). For example, the UE may receive services from two 3GPP accesses connected to a single CN (Core Network) (or from two 3GPP accesses belonging to the same network). Alternatively, the UE may receive services from two 3GPP accesses connected to different CNs (or from two 3GPP accesses belonging to different networks). In the above, the network may be a PLMN or an NPN.

[0374] And, for some services, traffic may be steered, switched, and split through a PDU Session formed through two 3GPP accesses. Here, this PDU Session may be referred to as a Multi-Access (MA) PDU Session. In the prior art, an MA PDU Session was established through a 3GPP access and a non-3GPP access, but in the disclosure of this specification, a PDU Session may be established through two 3GPP accesses.

[0375] For some services, traffic may be transmitted through a PDU Session established via a single 3GPP access.

[0376] In the dual-steering example described above, it is assumed that the UE has a single subscription. Conventional technology has the problem of the UE registering with only one 5G CN for 3GPP access. Furthermore, conventional technology has not defined a method for providing services to the UE via two 3GPP accesses.

[0377] However, a UE may need to register with two 5G CNs to receive services over two 3GPP accesses. Furthermore, a UE may need to perform separate registration procedures for each 3GPP access, even for a single 5G CN, to receive services over two 3GPP accesses.

[0378] Additionally, if a UE is registered to two 5G CNs, the UE may need to select and / or decide on which 5G CN to establish a PDU Session for which service and to which 5G CN to transmit traffic.

[0379] A terminal can attempt dual 3GPP access to the same PLMN. That is, a terminal can perform dual registration for the same PLMN. In this case, each network within the 5GC (e.g., each network associated with two 3GPP accesses to which the terminal is registered) needs to be separately identified to other NFs within the 5GC (e.g., SMF, PCF, etc.). However, the prior art has the problem that each network is not distinguishable.

[0380] A terminal can be dual-registered to the same PLMN using the same RAT type. In this case, an identifier that can distinguish each network involved in 3GPP access is required at each registration stage. Conventional technology does not provide such an identifier. The SMF may wish to transmit N2 SM information to an NG-RAN belonging to a specific network or to a specific NG-RAN. In this case, in a dual registration situation, the conventional technology has a problem in that the AMF cannot clearly identify which network or which NG-RAN the SMF is targeting belongs to.

[0381] Accordingly, in various examples disclosed in this specification, during the registration process, the terminal or AMF can assign / set a Reg ID for the current network. Furthermore, during the PDU Session Establishment process, the terminal or AMF can notify the SMF of the Reg ID. Furthermore, based on the Reg ID received from the AMF, the SMF can clearly inform the AMF of the network or NG-RAN to which the NG-RAN to which N2 SM information is to be transmitted belongs.

[0382] In various examples disclosed in this specification, during the registration process, the terminal or AMF can allocate / set a Reg ID for the corresponding network / registration. During the PDU Session Establishment process, the terminal or AMF can notify the SMF of the Reg ID. In addition, for a dual-registered terminal, the SMF can transmit N2 SM information to the NG-RAN. During this process, the SMF can also transmit the Target Reg ID to the AMF to notify the AMF of the target network or target NG-RAN to which the NG-RAN to be received belongs.

[0383] A method for supporting Dual Steering, as suggested in various examples of the disclosure of this specification, is comprised of a combination of one or more of the following operations / configurations / steps. Dual Steering / Steer support / provision / service may also be interpreted as Dual Registration support / provision / service.

[0384] In this specification, UE (User Equipment) and terminal may be used as terms with the same meaning.

[0385] In this specification, the terms “Subscriber” and “User” may be used interchangeably.

[0386] In this specification, the terms network, Core Network (CN), 5G CN, 3GPP network, and 3GPP system may be used interchangeably.

[0387] In this specification, Home Network, Subscribed Network, and Non-roaming Network are used interchangeably.

[0388] In this specification, the terms Visited Network, Non-subscribed Network, Roaming Network, and Non-home Network may be used interchangeably.

[0389] In this specification, the network may include a PLMN and a Non-Public Network (NPN).

[0390] In this specification, NPN may include both PNI-NPN (Public Network Integrated Non-Public Network) and SNPN (Stand-alone Non-Public Network), or may include only SNPN.

[0391] In this specification, PLMN may be interpreted to include PNI-NPN.

[0392] In this specification, the network identifier or network identification information may be a PLMN ID or a PLMN ID and NID (which is an SNPN ID).

[0393] In this specification, Reg ID can be defined in various forms. For example, it can be defined and used in various forms such as a simple number, [Primary 3GPP path, Secondary 3GPP path], numbering, RAT type, [RAT type + Network ID of 3GPP Access Network (e.g., PLMN ID, SNPN ID, etc.)], etc. In addition, Reg ID can also be referred to by other names (e.g., Path ID, Access ID, 3GPP Access ID, etc.).

[0394] In this specification, 3GPP access may mean 3GPP access including some or all of the RAT types as in the examples in Table 3, or may mean 3GPP access identical to some or all of the RAT types. For reference, RAT type may be referred to as radio technology or access type or access link technology or RAT information or 3GPP access type / information or 3GPP RAT type / information. For reference, the examples in Table 3 may also be defined in Table 5.4.3.2-1 of TS 29.571 V18.2.0.

[0395] Enumeration value Description"NR"New Radio"EUTRA"(WB) Evolved Universal Terrestrial Radio Access"WLAN"Untrusted Wireless LAN (IEEE 802.11) access"VIRTUAL"Virtual (see NOTE 1)"NBIOT"NB IoT"WIRELINE"Wireline access"WIRELINE_CABLE"Wireline Cable access"WIRELINE_BBF"Wireline BBF access"LTE-M"LTE-M (see NOTE 2)"NR_U"New Radio in unlicensed bands"EUTRA_U"(WB) Evolved Universal Terrestrial Radio Access in unlicensed bands"TRUSTED_N3GA"Trusted Non-3GPP access"TRUSTED_WLAN"Trusted Wireless LAN (IEEE 802.11) access"UTRA"UMTS Terrestrial Radio Access"GERA"GSM EDGE Radio Access Network"NR_LEO"NR (LEO) satellite access type"NR_MEO"NR (MEO) satellite access type"NR_GEO"NR (GEO) satellite access type"NR_OTHER_SAT"NR (OTHERSAT) satellite access type"NR_REDCAP"NR RedCap access type (see NOTE 3)NOTE 1: virtual is used when the N3IWF does not know the access technology used for the untrusted non-3GPP connection.NOTE 2: This RAT type value is only used in the core network and only when a Category M UE using E-UTRA has provided a Category M indication to the NG-RAN.NOTE 3: This RAT type value is only used in the core network and should only be used for UEs using NR with reduced radio capabilities provided to NG-RAN.

[0396] The examples in Table 3 illustrate examples of Enumeration RatType. The values ​​specified in Enumeration value can correspond to the descriptions in the same row.

[0397] The RAT types in Table 3 are only examples, and the scope of the disclosure of this specification is not limited by the RAT types in Table 3. The RAT types may be classified into various forms, more detailed forms, or multiple stages. For example, in the case of NR, the RAT types may be classified into FR (Frequency Range) 1 and FR2. As another example, in the case of NR, the RAT types may be classified into TN (Terrestrial Network) and NTN (Non-Terrestrial Network). Alternatively, in the case of NR, the RAT types may first be classified into TN and NTN, and then, in the case of NTN, may be further classified into GEO (Geosynchronous Orbit), MEO (Medium Earth Orbit), LEO (Low Earth Orbit), etc.

[0398] In this specification, the terms service, application and traffic may be used interchangeably.

[0399] In this specification, URSP and URSP rule(s) may be used as terms with the same meaning.

[0400] In this specification, a UE must connect to two 3GPP access points for dual steer (or to receive dual steer services or to transmit and receive traffic in a dual steer configuration). The base stations for dual steer communication may be the same or different, and the CNs may be the same or different. Furthermore, if the CNs are the same, the serving AMFs may be the same or different.

[0401] In this specification, Multi-Access (MA) may be used as a term with the same meaning as Dual-Access (DA), Dual Steer (DS), Dual Steering, Dual 3GPP Access, Multi 3GPP Access, etc.

[0402] In this specification, Multi-Access (MA) PDU Session may be used as a term with the same meaning as Dual-Access (DA) PDU Session, Dual Steer (DS) PDU Session, Dual Steering PDU Session, Dual 3GPP Access PDU Session, Multi 3GPP Access PDU Session, etc. It may mean "A PDU Session that provides a PDU connectivity service, which can use one 3GPP access network at a time, or simultaneously two 3GPP access networks."

[0403] This specification primarily focuses on the contents proposed in the disclosure, and parts where the same technology as the prior art is applied are omitted. For operations and procedures related to the 5G system, Registration, PDU Session, Multi-Access (MA) PDU Session, URSP, Steering of Roaming, etc., parts not mentioned in this specification shall be referred to TS 23.501 V18.0.0, TS 23.502 V18.0.0, TS 23.503 V18.0.0, and TS 23.122 V18.0.0.

[0404] In the method supporting Dual steering proposed in this specification, CN is mainly described as 5G CN, but the disclosure of this specification can also be applied when CN is EPC.

[0405] For some of the service operations between Core NFs described below, new service operations may be defined and used. Furthermore, for some of the NG messages between AMF and NG-RAN described below, new NG messages may be defined and used. Furthermore, for some of the RRC messages between NG-RAN and UEs described below, new RRC messages may be defined and used.

[0406] In the procedures below, some steps may be performed concurrently / in parallel, or in an out-of-order manner.

[0407] The names of the indication or parameter information suggested below are examples and may be interpreted as other names for the proposed procedure / purpose / method.

[0408] 1. First disclosure of this specification

[0409] The first disclosure of this specification describes an example of a registration procedure to support dual steering.

[0410] Hereinafter, the first to fourth examples of the first disclosure of the present specification will be described with reference to FIGS. 12a and 12b to 15a and 15b.

[0411] Hereinafter, a first example of the first disclosure of the present specification will be described with reference to FIGS. 12a and 12b.

[0412] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0413] Figures 12a and 12b illustrate a first example of the first disclosure of the present specification.

[0414] Figures 12a and 12b illustrate examples of a process in which a terminal registers with a network to receive dual-steer services. During the registration process, AMF #2 connects to AMF #1, and AMF #2 can request the Reg ID assigned / configured by AMF #1 for the 3GPP Access network of Network #1 (i.e., 3GPP Access Network #1). AMF #2 can assign / configure a new Reg ID based on the Reg ID of AMF #1. In the disclosure of this specification, the Reg ID is a Registration ID.

[0415] A terminal may attempt dual registration for Network #1 and Network #2, or may attempt dual registration for the same network (i.e., Network #1). During the dual registration process, different AMFs (i.e., AMF #1 and AMF #2) may be used, or the same AMF (i.e., AMF #1) may be used. Additionally, during the dual registration process, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs), or may access them using the same RAT.

[0416] Step 1: The terminal may send a registration request message. For example, the registration request message may include information related to dual registration.

[0417] For example, a terminal may first attempt to register with Network #1 to receive dual-steer services from two networks. The terminal may transmit a Registration Request message, including an indication that dual registration is required, to AMF #1 via NG-RAN #1.

[0418] Step 2: AMF #1 can assign a Reg ID.

[0419] For example, AMF #1 can assign / configure an ID (i.e., Reg ID) that other NFs (e.g., SMF, UDM, PCF, etc.) can use to identify the corresponding 3GPP Access Network (i.e., the 3GPP Access Network of Network #1) in a Dual registration situation. In addition, AMF #1 can store identifier information such as the RAN UE NGAP ID assigned by NG-RAN #1, the AMF UE NGAP ID assigned by AMF #1 to the corresponding UE, etc., together with the Reg ID. When other NFs transmit UE-associated signaling to the corresponding UE or NG-RAN #1 together with the Reg ID to AMF #1, AMF #1 can select an appropriate NGAP UE association based on the stored information.

[0420] Step 3: AMF#1 can send a request message related to the Session Management (SM) context of the PDU session to SMF.

[0421] In Step 1, the Registration Request message transmitted by the UE may include a List Of PDU Sessions To Be Activated IE. In this case, AMF #1 can request activation for the corresponding PDU Session by transmitting an Nsmf_PDUSession_UpdateSMContext Request message (e.g., which may include the List Of PDU Sessions To Be Activated IE) to the SMF. AMF #1 can transmit the Reg ID value allocated / configured for the 3GPP Access network of Network #1 in Step 2 to the SMF along with the Nsmf_PDUSession_UpdateSMContext Request message. In addition, AMF #1 can transmit to the SMF the RAT type used by the UE in each network, the current location information of the UE within each network, etc.

[0422] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0423] Step 4: SMF can send a response message to AMF#1.

[0424] For example, SMF can perform activation on the PDU Session list requested in Step 3. SMF responds to AMF #1 with the activation result via the Nsmf_PDUSession_UpdateSMContext Response message.

[0425] If AMF #1 transmits Reg ID in Step 3, AMF #1 stores the activation result along with the RAT type used in the access process, AMF #1 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via 3GPP Access Network #1 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0426] Note that steps 3 and 4 may be performed optionally.

[0427] Step 5: AMF #1 can send a Registration Accept message to the terminal.

[0428] At this time, AMF #1 may also send a Registration Accept message containing the Reg ID to the terminal. If the Registration Accept message includes the Reg ID, the terminal may use that information in the next registration process for the dual-steer service.

[0429] Step 6: The terminal can send a registration request message to AMF#2.

[0430] For example, a terminal attempts to register with a second network to receive dual-steer service from two networks. Network #2 is shown as an example of the network with which the terminal attempts to register second in FIGS. 12A and 12B , but this is merely an example. For example, the terminal may attempt another registration with Network #1, and the descriptions of the disclosure herein may also apply in this case.

[0431] A terminal may transmit a registration request message containing information related to dual registration. For example, the terminal may transmit a Registration Request message containing an indication that dual registration is required to AMF #2 via NG-RAN #2.

[0432] The first network a terminal registers with and the second network may be the same network. In this case, instead of the registration procedure, another procedure (e.g., a procedure for adding a second 3GPP access, for which a newly defined procedure / NAS message may be used) may be used. The descriptions of the procedures and messages performed when the two networks are the same are applicable throughout this specification.

[0433] Step 7: AMF#2 can send a Namf_Communicaiton_UEContext Transfer Request message to AMF#1.

[0434] For example, based on information related to dual registration, AMF #2 can request UE Context for the corresponding terminal from AMF #1 by sending Namf_Communicaiton_UEContext Transfer Request message to AMF #1. During this process, AMF # may also send an indication indicating that a Dual Registration situation exists.

[0435] Step 8: AMF #1 can send a Namf_Communicaiton_UEContext Transfer Response message containing the UE context to AMF #2. At this time, AMF #1 can include the Reg ID for the 3GPP Access Network #1 allocated in Step 2 in the Namf_Communicaiton_UEContext Transfer Response message.

[0436] Step 9: AMF #2 can assign a Reg ID.

[0437] For example, AMF #2 allocates / sets an ID (i.e. Reg ID) that other NFs (e.g., SMF, UDM, PCF, etc.) will use to identify the corresponding 3GPP Access network (i.e., the 3GPP Access network of Network #2) in a Dual registration situation.

[0438] AMF #2 may consider the Reg ID received in Step 8, i.e., the Reg ID assigned / configured by AMF #1 for 3GPP Access Network #1. For example, AMF #2 may assign the Reg ID so that the 3GPP Access network of Network #1 and the 3GPP Access network of Network #2 can be identified by different Reg IDs.

[0439] Even when Network #1 and Network #2 are the same (i.e., when the terminal dual-registers only for 3GPP Access Network #1), the access via NG-RAN #1 and the access via NG-RAN #2 must be distinguished. To distinguish between the two accesses, AMF #2 assigns / sets a value that is distinct from the Reg ID assigned by AMF #1. Alternatively, when a terminal accesses two networks via the same RAT type, AMF #2 assigns a Reg ID so that each access can be identified through a different Reg ID.

[0440] Additionally, AMF #2 can store identifier information such as the RAN UE NGAP ID assigned by NG-RAN #2, the AMF UE NGAP ID assigned by AMF #2 for the corresponding UE, etc., together with the Reg ID. When other NFs transmit UE-associated signaling to the corresponding UE or NG-RAN #2, along with the Reg ID, to AMF #2, AMF #2 can appropriately select the NGAP UE association based on the stored information.

[0441] Step 10: AMF#2 can send a request message related to the Session Management (SM) context of the PDU session to SMF.

[0442] In Step 6, the Registration Request message transmitted by the UE may include a List Of PDU Sessions To Be Activated IE. In this case, AMF #2 can request activation for the corresponding PDU Session by transmitting an Nsmf_PDUSession_UpdateSMContext Request message (e.g., which may include the List Of PDU Sessions To Be Activated IE) to the SMF. AMF #2 can transmit the Reg ID value allocated / configured for the 3GPP Access network of Network #2 in Step 9 to the SMF along with the Nsmf_PDUSession_UpdateSMContext Request message. In addition, AMF #2 can transmit to the SMF the RAT type used by the UE in each network, the current location information of the UE within each network, etc.

[0443] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0444] Step 11: SMF can send a response message to AMF#2.

[0445] For example, SMF can perform activation on the PDU Session list requested in Step 10. SMF responds to AMF #2 with the activation result via the Nsmf_PDUSession_UpdateSMContext Response message.

[0446] If AMF #2 transmits Reg ID in Step 10, AMF #2 stores the activation result along with the RAT type used in the access process, AMF #2 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via 3GPP Access Network #2 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0447] Step 12: AMF #2 can send a Registration Accept message to the terminal.

[0448] At this time, AMF #2 may also send a Registration Accept message containing the Reg ID to the terminal. If the Registration Accept message includes the Reg ID, the terminal may use that information in the next registration process for the dual-steer service.

[0449] Hereinafter, a second example of the first disclosure of the present specification will be described with reference to FIGS. 13a and 13b.

[0450] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0451] Figures 13a and 13b show a second example of the first disclosure of the present specification.

[0452] In FIGS. 13A and 13B , a terminal may perform a registration procedure with a network to receive dual-steer services. During the registration procedure, AMF #1 may provide AMF #2 with a Reg ID allocated / configured for the 3GPP Access network of Network #1 (i.e., 3GPP Access Network #1) through the terminal. AMF #2 may then allocate / configure a new Reg ID based on the Reg ID of AMF #1.

[0453] A terminal may attempt dual registration for Network #1 and Network #2, or may attempt dual registration for the same network (i.e., Network #1). During the dual registration process, different AMFs (i.e., AMF #1 and AMF #2) may be used, or the same AMF (i.e., AMF #1) may be used. Additionally, during the dual registration process, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs), or may access them using the same RAT.

[0454] Step 1~4: Can be performed in the same manner as steps 1 to 4 of FIGS. 12a and 12b.

[0455] Step 5: AMF #1 sends a Registration Accept message to the terminal. At this time, AMF #1 can include the Reg ID in the Registration Accept message. If the terminal receives the Reg ID included in the Registration Accept message, the terminal uses the Reg ID information in the subsequent registration process for the dual-steer service.

[0456] Step 6: The terminal can send a registration request message to AMF#2.

[0457] For example, a terminal attempts to register with a second network to receive dual-steer service from two networks. Network #2 is shown as an example of the network with which the terminal attempts to register second in FIGS. 13A and 13B , but this is merely an example. For example, the terminal may attempt another registration with Network #1, and the descriptions of the disclosure herein may also apply in this case.

[0458] The terminal may transmit a registration request message containing information related to dual registration. For example, the terminal may transmit a registration request message containing an indication that dual registration is required to AMF #2 via NG-RAN #2. The terminal may also transmit the Reg ID (e.g., the Reg ID allocated / configured by AMF #1 for the 3GPP access network of Network #1) received in step 5.

[0459] Step 7~8: Can be performed in the same manner as steps 9~10 of FIG. 12a and FIG. 12b.

[0460] Step 9: SMF can send a response message to AMF#2.

[0461] For example, SMF can perform activation on the PDU Session list requested in Step 8. SMF responds to AMF #2 with the activation result via the Nsmf_PDUSession_UpdateSMContext Response message.

[0462] If AMF #2 transmits Reg ID in Step 8, AMF #2 stores the activation result along with the RAT type used in the access process, AMF #2 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via 3GPP Access Network #2 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0463] Step 10: AMF #2 can send a Registration Accept message to the terminal.

[0464] At this time, AMF #2 may also send a Registration Accept message containing the Reg ID to the terminal. If the Registration Accept message includes the Reg ID, the terminal may use that information in the next registration process for the dual-steer service.

[0465] Hereinafter, a third example of the first disclosure of the present specification will be described with reference to FIGS. 14a and 14b.

[0466] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0467] Figures 14a and 14b show a third example of the first disclosure of the present specification.

[0468] According to FIGS. 14a and 14b, a terminal may perform registration with a network to receive dual-steer service. In this process, the terminal may provide each AMF with a Reg ID allocated / set for each network (i.e., the 3GPP Access network of Network #1 (i.e., 3GPP Access Network #1) and / or the 3GPP Access network of Network #2 (i.e., 3GPP Access Network #2)) via a Registration Request message.

[0469] A terminal may attempt dual registration for Network #1 and Network #2, or may attempt dual registration for the same network (i.e., Network #1). During the dual registration process, different AMFs (i.e., AMF #1 and AMF #2) may be used, or the same AMF (i.e., AMF #1) may be used. Additionally, during the dual registration process, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs), or may access them using the same RAT.

[0470] Step 1: The terminal can be assigned a Reg ID.

[0471] For example, a terminal decides to receive dual-steer service from two networks. To do this, the terminal first allocates / configures an ID (i.e., Reg ID) that different NFs (e.g., AMF, SMF, UDM, PCF, etc.) of the corresponding networks will use to identify the corresponding 3GPP Access network (i.e., the 3GPP Access network of Network #1) in a Dual Registration situation.

[0472] Step 2: The terminal may send a registration request message. For example, the registration request message may include information related to dual registration.

[0473] For example, a terminal may first attempt to register with Network #1 to receive dual-steer services from two networks. The terminal may send a Registration Request message to AMF #1 via NG-RAN #1, including an indication that dual registration is required. Additionally, the terminal may include the Reg ID assigned / configured for 3GPP Access Network #1 in the Registration Request message.

[0474] AMF #1 can store identifier information such as Reg ID included in the Registration Request message, RAN UE NGAP ID assigned by NG-RAN #1, and AMF UE NGAP ID assigned by AMF #1 for the corresponding UE. When other NFs send UE-associated signaling to the corresponding UE or NG-RAN #1 along with Reg ID to AMF #1, AMF #1 can select an appropriate NGAP UE association based on the stored information.

[0475] Step 3: In Step 2, the UE may have included the List Of PDU Sessions To Be Activated IE in the Registration Request message. In this case, AMF #1 can request SMF to activate the corresponding PDU Session by sending the Nsmf_PDUSession_UpdateSMContext Request message to the SMF. During this process, AMF #1 can also transmit to the SMF the Reg ID value that the UE allocated / configured for the 3GPP Access network of Network #1 in Step 1. In addition, AMF #1 can also transmit to the SMF the RAT type used by the UE in each network and the current location information of the UE within each network.

[0476] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0477] Step 4: It can be performed in the same manner as step 4 of FIG. 12a and FIG. 12b.

[0478] Step 5: AMF #1 can send a Registration Accept message to the terminal.

[0479] Step 6: To perform registration to the second network, the terminal can be assigned a Reg ID.

[0480] For example, a terminal may know that it needs to register with a second network to receive dual-steer services from two networks. Therefore, the terminal allocates / configures an ID (i.e., Reg ID) that different NFs (e.g., AMF, SMF, UDM, PCF, etc.) of the corresponding networks will use to identify the corresponding 3GPP Access network (i.e., the 3GPP Access network of Network #2) in a dual registration situation.

[0481] At this time, the terminal may consider the Reg ID allocated / configured by the terminal for the 3GPP Access network of Network #1 in Step 1. That is, for example, the terminal may allocate the Reg ID so that the 3GPP Access network of Network #1 and the 3GPP Access network of Network #2 can be identified through different Reg IDs.

[0482] Even when Network #1 and Network #2 are the same (i.e., when the terminal dual-registers only for 3GPP Access Network #1), the connection via NG-RAN #1 and the connection via NG-RAN #2 must be distinguished. To distinguish between the two connections, the terminal assigns / configures a Reg ID that is distinct from the Reg ID assigned / configured in Step 1. Alternatively, when the terminal connects to two networks via the same RAT type, the terminal assigns a Reg ID so that each connection can be identified through a different Reg ID.

[0483] Step 7: The terminal can send a registration request message to AMF#2.

[0484] For example, a terminal attempts to register with a second network to receive dual-steer service from two networks. Network #2 is shown as an example of the network with which the terminal attempts to register second in FIGS. 14a and 14b , but this is merely an example. For example, the terminal may attempt another registration with Network #1, and the descriptions of the disclosure herein may also apply in this case.

[0485] The terminal can transmit a registration request message containing information related to dual registration. For example, the terminal transmits a Registration Request message containing an indication that dual registration is required to AMF #2 via NG-RAN #2. Additionally, the terminal can include the Reg ID allocated / configured for 3GPP Access Network #2 in Step 6 in the registration request message.

[0486] AMF #2 can store identifier information such as Reg ID included in the Registration Request message, RAN UE NGAP ID assigned by NG-RAN #2, and AMF UE NGAP ID assigned by AMF #2 for the corresponding UE. When other NFs send UE-associated signaling to the corresponding UE or NG-RAN #2 along with Reg ID to AMF #2, AMF #2 can select an appropriate NGAP UE association based on the stored information.

[0487] Step 8: In Step 6, the UE may have included the List Of PDU Sessions To Be Activated IE in the Registration Request message. In this case, AMF #2 can request the SMF to activate the corresponding PDU Session by sending the Nsmf_PDUSession_UpdateSMContext Request message to the SMF. During this process, AMF #2 may also transmit to the SMF the Reg ID value that the UE allocated / configured for the 3GPP Access network of Network #2 in Step 6. In addition, AMF #2 may also transmit to the SMF the RAT type used by the UE in each network and the current location information of the UE within each network.

[0488] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0489] Step 9: SMF can send a response message to AMF#2.

[0490] For example, SMF can perform activation on the PDU Session list requested in Step 8. SMF responds to AMF #2 with the activation result via the Nsmf_PDUSession_UpdateSMContext Response message.

[0491] If AMF #2 transmits Reg ID in Step 8, AMF #2 stores the activation result along with the RAT type used in the access process, AMF #2 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via Network #2 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0492] Step 10: AMF #2 can send a Registration Accept message to the terminal.

[0493] Hereinafter, the fourth example of the first disclosure of the present specification will be described with reference to FIGS. 15a and 15b.

[0494] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0495] Figures 15a and 15b show the fourth example of the first disclosure of the present specification.

[0496] In FIGS. 15A and 15B , a terminal may perform a registration procedure with a network to receive dual-steer services. During the registration procedure, AMF #2 may access the UDM and request the Reg ID assigned / configured by AMF #1 for the 3GPP Access network of Network #1 (i.e., 3GPP Access Network #1). Based on the Reg ID assigned by AMF #1, AMF #2 may assign / configure a new Reg ID.

[0497] A terminal may attempt dual registration for Network #1 and Network #2, or may attempt dual registration for the same network (i.e., Network #1). During the dual registration process, different AMFs (i.e., AMF #1 and AMF #2) may be used, or the same AMF (i.e., AMF #1) may be used. Additionally, during the dual registration process, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs), or may access them using the same RAT.

[0498] Step 1: It can be performed in the same manner as Step 1 of Figs. 12a and 12b.

[0499] Step 2: AMF #1 can send the Nudm_SDM_Get message to UDM.

[0500] For example, AMF #1 can send a Nudm_SDM_Get message to UDM to retrieve Access and Mobility Subscription data, SMF Selection Subscription data, etc.

[0501] Step 3: UDM can send Nudm_SDM_Get Response message to AMF #1.

[0502] For example, UDM can send Nudm_SDM_Get Response message containing Access and Mobility Subscription data, SMF Selection Subscription data, etc. to AMF #1. If there is already a network with which the terminal is Dual Registered, UDM can also send Reg ID allocated / configured for the 3GPP Access network to AMF #1.

[0503] Step 4: AMF #1 can assign a Reg ID.

[0504] For example, AMF #1 can assign / set an ID (i.e. Reg ID) that other NFs (e.g., SMF, UDM, PCF, etc.) will use to identify the corresponding 3GPP Access network (i.e., the 3GPP Access network of Network #1) in a Dual registration situation.

[0505] If in Step 3, AMF #1 receives a Reg ID from UDM, AMF #1 allocates / sets a Reg ID for 3GPP Access Network #1 so that the 3GPP Access Network associated with the received Reg ID and the 3GPP Access Network of Network #1 can be identified through different Reg IDs.

[0506] Additionally, AMF #1 can store identifier information such as the RAN UE NGAP ID assigned by NG-RAN #1, the AMF UE NGAP ID assigned by AMF #1 for the corresponding UE, etc., along with the Reg ID. When other NFs transmit UE-associated signaling to the corresponding UE or NG-RAN #1, along with the Reg ID, to AMF #1, AMF #1 can appropriately select the NGAP UE association based on the stored information.

[0507] Step 5: AMF #1 registers with UDM based on Nudm_UECM_Registration. During this process, AMF #1 also transmits the Reg ID value assigned / set in Step 4 to UDM. Therefore, UDM can store SUPI, RAT type, Reg ID, etc., and can also store the corresponding information in UDR via the Nudr_DM_Update message.

[0508] Step 6: AMF#1 can send a request message related to the Session Management (SM) context of the PDU session to SMF.

[0509] In Step 1, the Registration Request message transmitted by the UE may include a List Of PDU Sessions To Be Activated IE. In this case, AMF #1 can request activation for the corresponding PDU Session by transmitting an Nsmf_PDUSession_UpdateSMContext Request message (e.g., which may include the List Of PDU Sessions To Be Activated IE) to the SMF. AMF #1 can transmit the Reg ID value allocated / configured for the 3GPP Access network of Network #1 in Step 4 to the SMF along with the Nsmf_PDUSession_UpdateSMContext Request message. In addition, AMF #1 can transmit to the SMF the RAT type used by the UE in each network, the current location information of the UE within each network, etc.

[0510] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0511] Step 7: SMF can send a response message to AMF#1.

[0512] For example, SMF can perform activation on the PDU Session list requested in Step 6. SMF responds to AMF #1 with the activation result via the Nsmf_PDUSession_UpdateSMContext Response message.

[0513] If AMF #1 transmits Reg ID in Step 6, AMF #1 stores the activation result along with the RAT type used in the access process, AMF #1 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via 3GPP Access Network #1 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0514] Step 8: AMF #1 can send a Registration Accept message to the terminal.

[0515] At this time, AMF #1 may also send a Registration Accept message containing the Reg ID to the terminal. If the Registration Accept message includes the Reg ID, the terminal may use that information in the next registration process for the dual-steer service.

[0516] Step 9: The terminal can send a registration request message to AMF#2.

[0517] For example, a terminal attempts to register with a second network to receive dual-steer service from two networks. Network #2 is shown as an example of the network with which the terminal attempts to register second in FIGS. 15A and 15B , but this is merely an example. For example, the terminal may attempt another registration with Network #1, and the descriptions of the disclosure herein may also apply in this case.

[0518] A terminal may transmit a registration request message containing information related to dual registration. For example, the terminal may transmit a Registration Request message containing an indication that dual registration is required to AMF #2 via NG-RAN #2.

[0519] Step 10: AMF #2 can send the Nudm_SDM_Get message to UDM.

[0520] For example, AMF #2 can send a Nudm_SDM_Get message to UDM to retrieve Access and Mobility Subscription data, SMF Selection Subscription data, etc.

[0521] Step 11: UDM can send Nudm_SDM_Get Response message to AMF #2.

[0522] For example, UDM can send Nudm_SDM_Get Response message containing Access and Mobility Subscription data, SMF Selection Subscription data, etc. to AMF #2. Since the terminal is already Dual Registered with Network #1, UDM can also send the Reg ID allocated / configured for the corresponding 3GPP Access network to AMF #2.

[0523] Step 12: AMF #2 can assign a Reg ID.

[0524] For example, AMF #2 can assign / set an ID (i.e. Reg ID) that other NFs (e.g., SMF, UDM, PCF, etc.) will use to identify the corresponding 3GPP Access network (i.e., the 3GPP Access network of Network #1) in a Dual registration situation.

[0525] If in Step 3, AMF #2 received Reg ID from UDM,

[0526] At this time, AMF#2 can consider the Reg ID received in Step 11, i.e. the Reg ID allocated / set by AMF#1 for the 3GPP Access network of Network#1.

[0527] To enable the 3GPP Access network of Network #1 and the 3GPP Access network of Network #2 to be identified by different Reg IDs, AMF #12 assigns / sets the Reg ID for 3GPP Access Network #2.

[0528] Even when Network #1 and Network #2 are the same (i.e., when the terminal dual-registers only for 3GPP Access Network #1), the access via NG-RAN #1 and the access via NG-RAN #2 must be distinguished. To distinguish between the two accesses, AMF #2 assigns / sets a value that is distinct from the Reg ID assigned by AMF #1. Alternatively, when a terminal accesses two networks via the same RAT type, AMF #2 assigns a Reg ID so that each access can be identified through a different Reg ID.

[0529] Additionally, AMF #2 can store identifier information such as the RAN UE NGAP ID assigned by NG-RAN #2, the AMF UE NGAP ID assigned by AMF #2 for the corresponding UE, etc., together with the Reg ID. When other NFs transmit UE-associated signaling to the corresponding UE or NG-RAN #2, along with the Reg ID, to AMF #2, AMF #2 can appropriately select the NGAP UE association based on the stored information.

[0530] Step 13: AMF #2 registers with UDM based on Nudm_UECM_Registration. During this process, AMF #2 also transmits the Reg ID value assigned / set in Step 12 to UDM. Therefore, UDM can store SUPI, RAT type, Reg ID, etc., and can also store the corresponding information in UDR via the Nudr_DM_Update message.

[0531] Step 14: AMF#2 can send a request message related to the Session Management (SM) context of the PDU session to SMF.

[0532] In Step 12, the Registration Request message transmitted by the UE may include a List Of PDU Sessions To Be Activated IE. In this case, AMF #2 can request activation for the corresponding PDU Session by transmitting an Nsmf_PDUSession_UpdateSMContext Request message (e.g., which may include the List Of PDU Sessions To Be Activated IE) to the SMF. AMF #2 can transmit the Reg ID value allocated / configured for the 3GPP Access network of Network #2 in Step 12 to the SMF along with the Nsmf_PDUSession_UpdateSMContext Request message. In addition, AMF #2 can transmit to the SMF the RAT type used by the UE in each network, the current location information of the UE within each network, etc.

[0533] During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID can provide the Reg ID to the UPF.

[0534] Step 15: SMF can send a response message to AMF#1.

[0535] For example, SMF can perform activation on the PDU Session list requested in Step 14. SMF responds the activation result to AMF #2 via the Nsmf_PDUSession_UpdateSMContext Response message.

[0536] If AMF #2 transmits Reg ID in Step 14, AMF #2 stores the activation result along with the RAT type used in the access process, AMF #2 ID, and current terminal location information. Later, SMF may want to send a message to the terminal via 3GPP Access Network #2 or perform NG-RAN resource setup. In this case, SMF can notify AMF that it wants to send a message to the terminal or perform NG-RAN resource setup by sending a message including Reg ID.

[0537] Step 16: AMF #2 can send a Registration Accept message to the terminal.

[0538] At this time, AMF #2 may also send a Registration Accept message containing the Reg ID to the terminal. If the Registration Accept message includes the Reg ID, the terminal may use that information in the next registration process for the dual-steer service.

[0539] 2. Second disclosure of this specification

[0540] The second disclosure of this specification describes an example of a service request procedure to support dual steering.

[0541] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0542] FIG. 16 illustrates an example of a service request procedure for supporting dual steering according to one embodiment of the disclosure of the present specification.

[0543] Figure 16 illustrates an example of a terminal performing a Service Request to the network to resume dual-steer service. During this process, the AMF may inform the SMF of the Reg ID(s) assigned / configured for the currently dual-registered 3GPP Access network(s).

[0544] The terminal may be dual registered to Network #1 and Network #2, or dual registered to the same network (i.e., Network #1). Alternatively, the terminal may be currently registered to only one network. Different AMFs (i.e., AMF #1 and AMF #2) may be used during this process, or the same AMF (i.e., AMF #1) may be used. Additionally, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used during this process, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs) or using the same RAT.

[0545] Step 1: UPF receives mobile terminated data for the PDU Session related to the currently dual registered terminal.

[0546] Step 2: UPF can send a Data Notification message to SMF.

[0547] For example, UPF can notify SMF that Mobile terminated data has been received via a Data Notification message. At this time, UPF can also send SMF Reg ID information to which the buffered packet should be transmitted, as described in the examples of FIGS. 17 and 18.

[0548] Step 3: SMF can send the Namf_Communication_N1N2MessageTransfer message to AMF.

[0549] For example, the SMF notifies the AMF that there is mobile terminated data or signaling to the terminal. At this time, the SMF can notify the AMF of the network to which the NGAP PAGING message should be delivered, i.e., the 3GPP Access network that is the paging target. To do this, the SMF can include the Target Reg ID in the Namf_Communication_N1N2MessageTransfer message.

[0550] Step 4: AMF can send a paging message to NG-RAN.

[0551] For example, based on the Target Reg ID received in Step 3, the AMF transmits an NGAP PAGING message to the NG-RAN belonging to the 3GPP Access network associated with the Target Reg ID or toward the NG-RAN.

[0552] Step 5: NG-RAN can send a paging message to the UE.

[0553] For example, an NG-RAN that receives a paging message from AMF pages the UE.

[0554] Steps 1 to 5 can only be executed if there is mobile terminated data or signaling for the corresponding terminal.

[0555] Step 6: The terminal can send a service request message to AMF.

[0556] For example, a terminal transmits a Service Request message to the network to receive mobile terminated data or signaling, or to transmit mobile originated data or signaling. If a Reg ID was received from the AMF during the Registration phase, the terminal may include the Reg ID in the Service Request message.

[0557] Step 7: AMF can send the Nsmf_PDUSession_UpdateSMContext Request message to SMF.

[0558] For example, AMF can request SMF to activate specific PDU Session(s) by sending Nsmf_PDUSession_UpdateSMContext Request message to SMF. At this time, Reg ID(s) for 3GPP Access network in which current UE is registered can be also transmitted to SMF. For example, if AMF knows that the UE is dual registered to two networks, AMF can inform SMF of Reg ID(s) associated with each 3GPP Access network. In addition, AMF can also transmit to SMF the RAT type used by the UE in each network, current location information of the UE within each network, etc.

[0559] Based on one or more of the procedures of FIGS. 12a and 12b to 15a and 15b, the AMF may store Reg ID(s) for the corresponding 3GPP Access network(s).

[0560] Step 8: Steps 5 to 10 of the UE Triggered Service Request procedure in Clause 4.2.3.2 of TS 23.502 V18.0.0 may be performed. During the N4 Session Establishment / N4 Session Modification process, the SMF that received the Reg ID may provide the Reg ID to the UPF.

[0561] Step 9: SMF can send the Nsmf_PDUSession_UpdateSMContext Response message to AMF.

[0562] For example, the SMF can notify the AMF of the request result in Step 7 by sending the Nsmf_PDUSession_UpdateSMContext Response message to the AMF. At this time, the SMF can include the Target Reg ID in the Nsmf_PDUSession_UpdateSMContext Response message to notify the AMF of which NG-RAN or NG-RAN belongs to which 3GPP Access network the N2 SM information included in the Nsmf_PDUSession_UpdateSMContext Response message is to be received.

[0563] In Step 7, the AMF may not have forwarded the Reg ID(s). In this case, the SMF may use the RAT type, serving network ID, and location information for each access received in Step 7 to inform the AMF of the 3GPP Access network or NG-RAN to which the NG-RAN belongs that should receive the N2 SM information.

[0564] Step 10: Based on the Target Reg ID received in Step 9, the AMF can forward the N2 SM information transmitted by the SMF to the NG-RAN belonging to the 3GPP Access network associated with the Target Reg ID or to the NG-RAN associated with the Target Reg ID. The AMF can also send a Service Accept message to be sent to the UE.

[0565] Step 11: The remaining steps of the UE Triggered Service Request procedure in Clause 4.2.3.2 of TS 23.502 may be performed.

[0566] 3. Third disclosure of this specification

[0567] The third disclosure of this specification describes an example of a PDU session establishment procedure to support dual steering.

[0568] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0569] FIG. 17 illustrates an example of a PDU session establishment procedure to support dual steering according to one embodiment of the disclosure of the present specification.

[0570] According to Figure 17, in order for a terminal to receive dual-steer service, the terminal may perform a PDU Session Establishment Request to the network. During this process, the AMF may inform the SMF of the Reg ID(s) allocated / configured for the currently dual-registered 3GPP Access network(s).

[0571] The terminal may be dual registered to Network #1 and Network #2, or dual registered to the same network (i.e., Network #1). Alternatively, the terminal may be currently registered to only one network. Different AMFs (i.e., AMF #1 and AMF #2) may be used during this process, or the same AMF (i.e., AMF #1) may be used. Additionally, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used during this process, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs) or using the same RAT.

[0572] Step 1: The terminal can send a PDU session establishment request message.

[0573] For example, a terminal can transmit a PDU Session establishment request message to the network to receive dual-steer service.

[0574] Step 2: AMF can select SMF.

[0575] For example, AMF selects an SMF that has the capability for dual-steer services. That is, AMF selects an SMF that supports dual-steer services.

[0576] Step 3: The AMF may send the Nsmf_PDUSession_CreateSMContext Request message to the SMF selected in Step 3. The AMF notifies the AMF that the UE has requested the creation of a PDU Session. At this time, the AMF may also send the SMF the Reg ID for the network for which the UE requested the PDU Session Establishment. For example, the AMF may send the SMF the Nsmf_PDUSession_CreateSMContext Request message including the Reg ID.

[0577] Additionally, the AMF can also transmit to the SMF the RAT type used by the terminal in each network, the terminal's current location information within each network, etc. The terminal may have requested to establish a PDU session that provides dual steer service (e.g., an MA PDU session or similar PDU session using two 3GPP accesses). In this case, if the AMF knows that the terminal is dual registered to two networks, the AMF can also transmit the Reg IDs associated with each network to the SMF.

[0578] Based on one or more of the procedures of FIGS. 12a and 12b through 15a and 15b, the AMF may store Reg ID(s) for the corresponding network(s).

[0579] Step 4: SMF can send the Nsmf_PDUSession_CreateSMContext Response message to AMF.

[0580] For example, after SMF creates an SM context related to the PDU Session requested from AMF in Step 3, SMF responds to AMF with an Nsmf_PDUSession_CreateSMContext Response message.

[0581] Step 5: Steps 6 to 10 may be performed among the PDU session establishment procedures of FIGS. 7 and 8.

[0582] During the N4 Session Establishment process, the SMF can provide the Reg ID to the UPF. For example, the Reg ID may be provided to the UPF as part of a Multi-Access Rule or Buffer Action Rule. Based on the Reg ID, the UPF can also send the Reg ID to the SMF when transmitting a downlink data notification. The UPF can then inform the SMF which 3GPP access should be used to perform user plane resource setup.

[0583] Step 6: SMF can send the Namf_Communication_N1N2MessageTransfer message to AMF.

[0584] For example, to enable NG-RAN to service the corresponding PDU Session, SMF can generate N2 SM information required for NG-RAN to allocate PDU Session resources. SMF can send Namf_Communication_N1N2MessageTransfer containing N2 SM information to AMF. At this time, SMF can also send Target Reg ID to inform which NG-RAN belongs to which 3GPP Access network the N2 SM information included in Namf_Communication_N1N2MessageTransfer message is to be received or to inform the receiving NG-RAN.

[0585] In Step 3, the AMF may not have forwarded the Reg ID(s) to the SMF. In this case, the SMF may use the RAT type, serving network ID, and location information for each access received in Step 3 to inform the AMF of the 3GPP Access network or NG-RAN to which the NG-RAN belongs that should receive the N2 SM information.

[0586] Step 7: Based on the Target Reg ID received in Step 6, the AMF can forward the N2 SM information transmitted by the SMF to the NG-RAN belonging to the corresponding 3GPP Access network or to the NG-RAN. The AMF can also send the PDU Session Establishment Accept message to be sent to the UE to the NG-RAN.

[0587] Step 8: Steps 13 to 21 may be performed among the PDU Session Establishment procedures of FIGS. 7 and 8.

[0588] Step 9: SMF can send the Namf_Communication_N1N2MessageTransfer message to AMF.

[0589] For example, to support a dual-steer service, the PDU Session must be serviced by an NG-RAN belonging to another 3GPP Access network or another NG-RAN in addition to the network selected in Step 6. To this end, the SMF can generate the N2 SM information required for the NG-RAN to allocate PDU Session resources. The SMF can transmit Namf_Communication_N1N2MessageTransfer containing the N2 SM information to the AMF. At this time, the SMF can also transmit the Target Reg ID to indicate which 3GPP Access network the NG-RAN belonging to is the recipient of the N2 SM information included in the Namf_Communication_N1N2MessageTransfer message or to inform the receiving NG-RAN.

[0590] At this time, a Target Reg ID having a different value from the Target Reg ID included in Step 6 may be included in the Namf_Communication_N1N2MessageTransfer message. That is, a Reg ID identifying a 3GPP Access network different from the network selected as the transmission target in Step 6 is included in the Namf_Communication_N1N2MessageTransfer message.

[0591] Step 10: AMF can send a PDU Session Resource Setup message to NG-RAN.

[0592] For example, based on the Target Reg ID received in Step 9, the AMF can transmit the N2 SM information transmitted by the SMF to the NG-RAN belonging to the network associated with the Target Reg ID or to the NG-RAN associated with the Target Reg ID.

[0593] In addition to the PDU Session Establishment procedure, the SMF can also transmit Target Reg ID information when performing other procedures (e.g., PDU Session Modification, PDU Session Release, PDU Session deactivation, etc.). For example, the SMF can transmit Target Reg ID information together with N2 SM information to a specific 3GPP Access network.

[0594] 4. Disclosure of the fourth paragraph of this specification

[0595] The fourth disclosure of this specification describes an example of an NG-based handover procedure to support dual steering.

[0596] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0597] FIG. 18 illustrates an NG-based handover procedure for supporting dual steering according to one embodiment of the disclosure of the present specification.

[0598] According to FIG. 18, while a terminal is receiving dual-steer service, it may be handed over to a Target-NG-RAN (T-NG-RAN) connected to a Target-AMF (T-AMF) due to mobility. During the handover process, the T-AMF may inform the SMF of the Reg ID(s) allocated / configured for the currently dual-registered 3GPP Access network(s).

[0599] The terminal may be dual registered to Network #1 and Network #2, or dual registered to the same network (i.e., Network #1). Alternatively, the terminal may be currently registered to only one network. Different AMFs (i.e., AMF #1 and AMF #2) may be used during this process, or the same AMF (i.e., AMF #1) may be used. Additionally, different NG-RANs (i.e., NG-RAN #1 and NG-RAN #2) may be used during this process, or the same NG-RAN (i.e., NG-RAN #1) may be used. The terminal may access each network (i.e., Network #1 and Network #2) using different radio access types (RATs) or using the same RAT.

[0600] For reference, in the example of Fig. 18, “S-” means “Source-” and “T-” means “Target-”.

[0601] Step 1: S-NG-RAN can send a HANDOVER REQUIRED message to S-AMF.

[0602] For example, the S-NG-RAN may decide to handover the UE to the T-NG-RAN. In this case, the S-NG-RAN may send a HANDOVER REQUIRED message to the S-AMF.

[0603] Step 2: S-AMF can select AMF.

[0604] For example, based on the Target ID information included in the HANDOVER REQUIRED message in Step 1, S-AMF selects T-AMF.

[0605] Step 3: S-AMF can send Namf_Communication_CreateUEContext Request message to T-AMF selected in Step 2.

[0606] The S-AMF can notify the T-AMF that the UE needs to be handed over by sending a Namf_Communication_CreateUEContext Request message. At this time, the S-AMF can also transmit the Reg ID value allocated / configured to identify the 3GPP Access network to the T-AMF. Based on one or more of the procedures among FIGS. 12a and 12b to 15a and 15b, the S-AMF may store the Reg ID(s) for the corresponding 3GPP Access network(s).

[0607] The T-AMF may use the Reg ID value received from the S-AMF as is. Alternatively, the T-AMF may assign / set a new Reg ID based on the received Reg ID. For example, if the PLMN or SNPN changes during the handover process, the T-AMF may assign / set a Reg ID that can identify the newly changed 3GPP Access network. In this case, the T-AMF may assign / set a new Reg ID based on one or more of the procedures of FIGS. 12a and 12b to 15a and 15b.

[0608] Step 4: T-AMF can send the Nsmf_PDUSession_UpdateSMContext Request message to SMF.

[0609] For example, T-AMF can notify SMF that a handover has occurred for the terminal and that an update to the PDU Session is required by sending the Nsmf_PDUSession_UpdateSMContext Request message.

[0610] At this time, T-AMF can include the Reg ID received from S-AMF in Step 3 or the Reg ID newly allocated / set by T-AMF itself in the Nsmf_PDUSession_UpdateSMContext Request message. The SMF that received the Reg ID stores the Reg ID value for the 3GPP Access network to which the terminal is handed over, along with the RAT type related to the access, T-AMF ID, and current terminal location information.

[0611] Later, when the SMF wants to send a message to a terminal through the corresponding 3GPP Access network, the SMF can inform the AMF that it wants to send the message through the corresponding 3GPP Access network by sending a message containing the Reg ID. In addition, the T-AMF can send the SMF information such as the RAT type used by the terminal in each 3GPP Access network and the terminal's current location information within each 3GPP Access network.

[0612] Step 5: The remaining steps of the NG-based Handover procedure according to Clause 4.9.1.3 of TS 23.502 can be performed.

[0613] For Xn handover, AMF can receive N2 Path Switch Request. AMF can include Reg ID allocated for that 3GPP access in Nsmf_PDUSession_UpdateSMContext Request and send it to SMF.

[0614] 5. Disclosure of Article 5 of this Specification

[0615] Disclosure 5 of this specification describes an example of N4 session management to support dual steering.

[0616] SMF can create an N4 Session Context for a PDU Session using dual 3GPP access and transmit the Reg ID information and N4 Session Context together to the UPF.

[0617] Based on this information, the UPF can send a downlink data notification to the SMF. For example, the UPF can send the SMF the Reg ID associated with the 3GPP access over which the buffered data should be transmitted. Based on this, the SMF can identify the 3GPP access over which user plane resource setup is required.

[0618] 5-1. MAR rule update

[0619] As follows, 3GPP Access Forwarding Action Information can be added based on the 3GPP Access Forwarding Action Information included in the Multi-Access Rule. For reference, for IEs not described in Table 4, the IEs in Table 7.5.2.8-1 of TS 29.244 V18.2.0 can be referenced.

[0620] Octet 1 and 2Create MAR IE Type = 165 (decimal)Octets 3 and 4Length = nInformation elementsPConditions / CommentsAppl.IE TypeSxaSxbSxcN4N4mbMAR IDMThis IE uniquely identifies a MAR among all MARs established for the given PFCP session.---X-MAR IDSteering FunctionalityMThis IE shall be present to indicate the traffic steering functionality.---X-Steering FunctionalitySteering ModeMThis IE shall be present to indicate the steering mode.---X-Steering Mode3GPP Access Forwarding Action InformationIf the CUE is registered to a 3GPP access, this IE shall be present to provide 3GPP access specific forwarding action information. Except when the steering mode is set to "Active-Standby" and the non-3GPP connection is the active access and the 3GPP connection is not used as a standby access, in which case this IE may be present. (NOTE applies)---X-3GPP Access Forwarding Action InformationAdditional 3GPP Access Forwarding Action InformationC If the PDU session is established over a dual 3GPP access, this IE shall be included.---X-Additional 3GPP Access Forwarding Action InformationNOTE 1: For " Active-Standby " steering mode, the network may decide not to define a standby access. In this case, the SMF shall either set the Priority IE within the (non-)3GPP Access Forwarding Action Information IE to the value "No Standby", or shall not include the (non-)3GPP Access Forwarding Action Information IE for those accesses that are not defined as standby accesses.

[0621] For reference, in the example in Table 4, Appl can mean Application. Sxa can be an interface between a CP and a UP within the same node or between closely located nodes. Sxb can be an interface between a CP and a UP on different nodes. Sxc can be an interface for signaling between CP functions on different nodes. N4mb can be N4 for mobile broadband applications.

[0622] The example in Table 4 illustrates an example of a Create MAR IE within a PFCP Session Establishment Request. Referring to the example in Table 4, Additional 3GPP Access Forwarding Action Information has been added according to the example disclosed in this specification.

[0623] Table 5 is an example of the 3GPP Access Forwarding Action Information IE included in the Create MAR IE of Table 4. For reference, for IEs not described in Table 5, the IEs in Table 7.5.2.8-2 of TS 29.244 V18.2.0 may be referenced.

[0624] Octet 1 and 23GPP Access Forwarding Action Information 1 IE Type = 166 (decimal) Octets 3 and 4 Length = n Information elements P Conditions / Comments Appl.IE Type Sxa Sxb Sxc N4 N4 mb FAR IDM This IE shall uniquely identify a FAR among all FARs configured for this PFCP session. --- X-FAR IDRAT Type O This IE may be present to provide the current RAT type for the DL FAR to the UP function for statistical purposes. --- X-RAT TypeReg IDC This IE shall be included if the PDU session is established over dual 3GPP access. XReg ID

[0625] As shown in the example in Table 5, 3GPP Access Forwarding Action Information can be used.

[0626] According to the disclosure of this specification, 3GPP Access Forwarding Action Information can be updated as Additional 3GPP Access Forwarding Action Information of Table 6.

[0627] Octet 1 and 2Non-3GPP Access Forwarding Action Information IE Type = 167 (decimal)Octet 3 and 4Length = nInformation elementsPConditions / CommentsAppl.IE TypeSxaSxbSxcN4N4mbThe same IEs and requirements as defined in Table 5 may apply.

[0628] Table 6 is an additional 3GPP access forwarding task information IE within the MAR generation IE defined in the disclosure of this specification.

[0629] 5-2. BAR rule update

[0630] In the disclosure of this specification, the Buffer Action Rule may be updated as follows.

[0631] For reference, for IEs not described in Table 7, the IEs in Table 7.5.2.6-1 of TS 29.244 V18.2.0 may be referenced. According to the disclosure of this specification, a Reg ID may be included in a BAR rule, as in the example in Table 7.

[0632] Octet 1 and 2Create BAR IE Type = 85 (decimal)Octet 3 and 4Length = nInformation elementsPConditions / CommentsAppl.IE TypeSxaSxbSxcN4N4mbBAR IDMThis IE shall uniquely identify the BARs provided for this PFCP session.X--X-BAR IDReg IDCThis IE shall be included if a PDU session is established via dual 3GPP access.XReg ID

[0633] Table 7 shows an example of the Create BAR IE within a PFCP session establishment request.

[0634] 5-3. Downlink Data Report Update

[0635] According to the disclosure of this specification, the Downlink Data Report may be updated as follows. Based on the updated Downlink Data Report, when the UPF transmits a downlink data notification, the UPF may also transmit the Reg ID associated with the 3GPP access to which the buffered packet should be transmitted.

[0636] For reference, for IEs not described in Table 8, the IEs in Table 7.5.8.2-1 of TS 29.244 V18.2.0 may be referenced.

[0637] Octet 1 and 2Downlink Data Report IE Type = 83 (decimal)Octets 3 and 4Length = nInformation elementsPConditions / CommentsAppl.IE TypeSxaSxbSxcN4N4mbPDR IDMThis IE identifies the PDR in which downlink data packets are received or discarded in the UP function. More than one IE of this type can be included to indicate multiple PDRs in which downlink data packets are received or discarded.X--XXPDR IDReg IDCThis IE shall be included if a PDU session is established via dual 3GPP access.XReg ID

[0638] The example in Table 8 shows an example of a Downlink Data Report IE within a PFC Session Report Request.

[0639] For reference, the first through fifth disclosures of this specification described above may be applied independently, or one or more examples may be applied in combination. For example, the first through fifth disclosures of this specification may all be applied in combination.

[0640] For example, after a registration procedure is performed according to the first disclosure of this specification, a PDU session establishment procedure may be performed according to the third disclosure of this specification.

[0641] Hereinafter, with reference to FIG. 19, an example of operations according to an embodiment of the disclosure of the present specification is described. The example of FIG. 19 may include operations based on an example including at least one of the first to fifth disclosures of the present specification.

[0642] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals, messages, and fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0643] FIG. 19 illustrates an example of operations according to one embodiment of the disclosure of the present specification.

[0644] For reference, the procedure illustrated in FIG. 19 is merely an example, and the scope of the disclosure of this specification is not limited by the example in FIG. 19.

[0645] For example, with respect to the example of FIG. 19, the operations described in the examples of FIGS. 1 to 18 may also be applied. For example, even if operations, contents, etc. are not directly described in the example of FIG. 19, operations, contents, etc. described in various examples of the disclosure of this specification may be applied.

[0646] The operations illustrated in FIG. 19 are merely examples, and the scope of the disclosure of this specification is not limited to the operations illustrated in FIG. 19.

[0647] In step (S1901), the UE may transmit a registration request message to the AMF.

[0648] For example, the registration request message may include information related to dual registration. For example, the information related to dual registration may include information that dual registration is required for multiple 3GPP access networks.

[0649] At step (S1902), AMF may send a registration acceptance message to the UE.

[0650] For example, steps (S1901) and (S1902) may be performed according to various examples of the first disclosure of the present specification.

[0651] In step (S1903), the UE may transmit a PDU session establishment request message to the AMF.

[0652] At step (S1904), AMF can send a request message to SMF.

[0653] For example, the request message may be an SM context request message related to a PDU session. For example, the request message may include a registration ID related to the network with which the UE requested establishment of the PDU session.

[0654] For example, the registration ID may be received based on the UE requiring dual registration to multiple 3GPP access networks.

[0655] For example, a UE may request the establishment of a PDU session that provides dual steering services. In this case, the AMF may send a request message to the SMF that includes the registration IDs associated with each of the two or more 3GPP access networks to which the UE is dual-registered.

[0656] For example, the SMF can send a Multi-Access Rule (MAR) or Buffer Action Rule (BAR) containing a registration ID to the UPF. Based on the registration ID, the UPF can determine for which 3GPP access user plane resource setup to perform.

[0657] At step (S1905), the SMF can transmit a message to the AMF.

[0658] For example, the SMF may send a message to the AMF to transfer N2 SM information. This message may include a target registration ID associated with the target NG-RAN to which the N2 SM information is to be transferred.

[0659] For example, AMF may transmit N2 SM information to target NG-RAN based on target registration ID.

[0660] For example, the SMF may send the AMF a PDU Session Establishment Accept message to be transmitted to the UE, along with N2 SM information. The AMF may send the PDU Session Establishment Accept message to the UE.

[0661] For example, steps (S1903) to (S1905) may be performed according to various examples of the third disclosure of the present specification.

[0662] For example, the registration ID may be assigned by the UE. Alternatively, the registration ID may be assigned by the AMF. Alternatively, the registration ID may be assigned by Unified Data Management (UDM).

[0663] The above drawings may be executed individually or together with other drawings.

[0664] According to one embodiment of the disclosure of the present specification, the SMF can inform the AMF of the 3GPP Access network to which the target NG-RAN belongs. For example, during the registration process of the terminal, the AMF can allocate / set the Reg ID for the corresponding 3GPP Access network. For example, during the PDU Session Establishment process, the AMF can transmit the Reg ID(s) for the network(s) in which the terminal is currently registered to the SMF. For example, the SMF can inform the AMF of the network to which the NG-RAN belongs or the receiving NG-RAN that should receive the N2 SM information associated with the corresponding PDU Session belongs.

[0665] This specification may have various effects.

[0666] For example, communication based on dual registration can be effectively supported. For example, a terminal can dual register with the same RAT type in the same 3GPP Access network. In this case, during the registration process, the terminal or AMF can allocate / configure a Reg ID that allows other NFs (e.g., SMF, PCF, etc.) to identify each 3GPP Access network. For a dual registered terminal, based on the Reg ID, the SMF can notify the AMF of the target network or target NG-RAN to which the NG-RAN that should receive the corresponding N2 SM information belongs. Therefore, the AMF can prevent the N2 SM information received from the SMF from being forwarded to an NG-RAN belonging to a network other than the target network or to another NG-RAN.

[0667] The effects that can be achieved through the specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0668] For reference, the operation of the terminal (e.g., UE) described in this specification may be implemented by the devices of FIGS. 1 to 3 described above. For example, the terminal may be the first device (100) or the second device (200) of FIG. 2. For example, the operation of the terminal described in this specification may be processed by one or more processors (102 or 202). The operation of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). The one or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (105 or 206), and execute the instructions / programs stored in one or more memories (104 or 204) to perform the operation of the terminal (e.g., UE) described in the disclosure of this specification.

[0669] Additionally, the commands for performing the operations of the terminal described in the disclosure of this specification may be stored in a non-volatile computer-readable storage medium. The storage medium may be included in one or more memories (104 or 204). In addition, the commands recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the terminal described in the disclosure of this specification.

[0670] For reference, the operations of a network node (e.g., AMF, SMF, UPF, UDM, H-PCF, NEF, AF, UDR, AUSF, etc.) or a base station (e.g., NG-RAN, gNB, RAN, (R)AN, etc.) described in this specification may be implemented by the devices of FIGS. 1 to 3 described below. For example, the network node or the base station may be the first device (100) or the second device (200) of FIG. 2. For example, the operations of the network node or the base station described in this specification may be processed by one or more processors (102 or 202). The operations of the terminal described in this specification may be stored in one or more memories (104 or 204) in the form of instructions / programs (e.g., instructions, executable codes) executable by one or more processors (102 or 202). One or more processors (102 or 202) may control one or more memories (104 or 204) and one or more transceivers (106 or 206), and execute instructions / programs stored in one or more memories (104 or 204) to perform operations of a network node or base station as described in the disclosure of this specification.

[0671] Additionally, the instructions for performing the operations of the network node or base station described in the disclosure of this specification may be stored in a non-volatile (or non-transitory) computer-readable storage medium having the instructions recorded thereon. The storage medium may be included in one or more memories (104 or 204). In addition, the instructions recorded in the storage medium may be executed by one or more processors (102 or 202) to perform the operations of the network node or base station described in the disclosure of this specification.

[0672] Although the preferred embodiments have been described above by way of example, the disclosure of this specification is not limited to these specific embodiments, and may be modified, changed, or improved in various forms within the scope described in the spirit and claims of this specification.

[0673] In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks. However, the order of the steps described is not limited, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the invention.

[0674] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined to implement a method. Other implementations are within the scope of the claims.

Claims

1. In the method by which the Session Management Function (SMF) performs communication, A step of receiving a Session Management (SM) context request message related to a Protocol Data Unit (PDU) session from the Access and Mobility Management Function (AMF), The above SM context request message includes a registration ID associated with the network in which the User Equipment (UE) requested establishment of a PDU session, and The registration ID is received based on the above UE requiring dual registration for multiple 3GPP access networks; and A step of transmitting a message for transferring N2 SM information to the AMF, A method characterized in that the above message includes a target registration ID related to a target NG-RAN to which the N2 SM information is to be transmitted.

2. In paragraph 1, Further comprising a step of transmitting to a Multi-Access Rule (MAR) or Buffer Action Rule (BAR) User Plane Function (UPF) including the above registration ID, A method characterized in that the above registration ID is used by the UPF to determine for which 3GPP access the user plane resource setup is to be performed.

3. In paragraph 1 or 2, A method characterized in that, based on the UE requesting establishment of a PDU session providing a dual steering service, a registration ID associated with each of two or more 3GPP access networks in which the UE is dually registered is included in the SM context request message.

4. In any one of paragraphs 1 to 3, A method characterized in that the target registration ID is used by the AMF to transmit the N2 SM information to the target NG-RAN.

5. In any one of paragraphs 1 to 4, A method characterized in that the above N2 SM information is transmitted to the AMF together with a PDU session establishment acceptance message to be transmitted to the UE.

6. In the Session Management Function (SMF) that performs communication, the SMF: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; An SMF that performs an operation based on the above command being executed by the one or more processors is a method according to any one of claims 1 to 5.

7. In the method of Access and Mobility Management Function (AMF) performing communication, A step of receiving a Protocol Data Unit (PDU) session establishment request message from a User Equipment (UE); A step of sending a Session Management (SM) context request message related to a Protocol Data Unit (PDU) session to the Session Management Function (SMF). The above SM context request message includes a registration ID related to the network for which the UE requested establishment of a PDU session, and Based on the above UE requiring dual registration for multiple 3GPP access networks, the registration ID is transmitted; and A step of receiving a message for transferring N2 SM information from the SMF, A method characterized in that the above message includes a target registration ID related to a target NG-RAN to which the N2 SM information is to be transmitted.

8. In paragraph 7, A step of receiving a registration request message including information related to dual registration from the UE; and A method further comprising the step of transmitting a registration acceptance message to the UE.

9. In paragraph 7 or 8, A method characterized in that, based on the UE requesting establishment of a PDU session providing a dual steering service, a registration ID associated with each of two or more 3GPP access networks in which the UE is dually registered is included in the SM context request message.

10. In any one of paragraphs 7 to 9, A method further comprising a step of transmitting the N2 SM information to the target NG-RAN based on the target registration ID.

11. In any one of paragraphs 7 to 10, A method characterized in that the N2 SM information is transmitted from the SMF together with a PDU session establishment acceptance message to be transmitted to the UE.

12. In any one of paragraphs 7 to 11, The above registration ID is assigned by the UE, or The above registration ID is assigned by the AMF, or A method characterized in that the above registration ID is assigned by Unified Data Management (UDM).

13. In the Access and Mobility Management Function (AMF) that performs communication, the AMF: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; An operation performed based on the above command being executed by the one or more processors is an AMF method according to any one of claims 7 to 12.

14. In the method of User Equipment (UE) performing communication, A step of sending a registration request message to the Access and Mobility Management Function (AMF), The above registration request message includes information that dual registration to multiple 3GPP access networks is required; A step of receiving a registration acceptance message from the AMF; and A step of transmitting a Protocol Data Unit (PDU) session establishment request message to the Session Management Function (SMF) via the AMF is included. Based on the information that the above dual registration is required, the AMF or Unified Data Management (UDM) assigns a registration ID for the 3GPP access network associated with the above registration request message, or A method characterized in that the UE assigns a registration ID for the 3GPP access network.

15. In paragraph 14, A method further comprising the step of receiving a PDU session establishment acceptance message from the SMF via the AMF.

16. In a User Equipment (UE) configured to operate in a wireless communication system, the UE: One or more transmitters and receivers; one or more processors; and comprising one or more memories capable of storing instructions and being operable to the one or more processors; The actions performed based on the above instructions being executed by the one or more processors are: A UE according to any one of claims 14 to 15.

Images