Method for performing store-and-forward

Abstract

An embodiment of the present disclosure comprises the steps in which: a first NF receives a notification of downlink data for a UE from a second NF; the first NF serves the UE and manages mobility of the UE, and determines whether the downlink data is to be transmitted to a first satellite on the basis that the first satellite and a feeder link are connected; and the first NF transmits a first modification request message for user plane context for the UE to the second NF, wherein the first modification request message includes information related to the first satellite, and on the basis of determining that the downlink data is not to be transmitted to the first satellite, the first modification request message includes an indication not to transmit the downlink data to the first satellite.

Description

How to perform STORE AND FORWARD

[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 in a timely manner, meeting both urgent market needs and the longer-term requirements outlined by the ITU-R (ITU radio communication sector) 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 method to reduce the delay of downlink data is required.

[0006] The downlink is transmitted via satellite to minimize delay.

[0007] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0008] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0009] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0010] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0011] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0012] Figure 6 shows an example of basic satellite operation.

[0013] Figure 7 shows an example of S&F satellite operation.

[0014] Figure 8 shows an example of operation at time T1 in S&F satellite operation.

[0015] Figure 9 shows an example of operation at time T2 in S&F satellite operation.

[0016] Figure 10 shows an example of operation at time T3 in S&F satellite operation.

[0017] Figures 11, 12 and 13 illustrate examples of operation in a split MME architecture according to the disclosure of this specification.

[0018] Figures 14, 15, 16 and 17 illustrate examples of operation in a split AMF architecture according to the disclosure of this specification.

[0019] Figure 18 illustrates the procedure of the first NF for the disclosure of this specification.

[0020] Figure 19 illustrates the S-GW procedure for the disclosure of this specification.

[0021] Figure 20 illustrates the SMF procedure for the disclosure of this specification.

[0022] 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 multicarrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented via wireless technologies such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be implemented via 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 E-UTRA (evolved UTRA). UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long-term evolution) is part of E-UMTS (evolved UMTS) that uses 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).

[0023] 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. However, aspects of this specification that are not limited to a 3GPP-based wireless communication system can be applied to other mobile communication systems.

[0024] 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.

[0025] 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."

[0026] 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."

[0027] 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.”

[0028] 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”.

[0029] 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."

[0030] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0031] 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).

[0032] 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.

[0033] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0034] 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.

[0035] 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).

[0036] 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.

[0037] 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.

[0038] Wireless devices (100a to 100f) refer to 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. Wireless devices (100a to 100f) may include, but are not limited to, robots (100a), vehicles (100b-1 and 100b-2), extended reality (XR) devices (100c), portable devices (100d), home appliances (100e), IoT devices (100f), and artificial intelligence (AI) devices / servers (400). For example, vehicles may include vehicles having wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include AR / VR / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs) and heads-up displays (HUDs) 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.

[0039] 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 functions, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a holographic 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.

[0040] For example, a UAV may be an aircraft that is unmanned and navigated by radio control signals.

[0041] For example, a VR device may include a device for implementing objects or backgrounds in a virtual environment. For example, an AR device may include a device that implements objects or backgrounds in a virtual world by connecting them to objects or backgrounds in the real world. For example, an MR device may include a device that implements objects or backgrounds in a virtual world by merging them with objects or backgrounds in the real world. For example, a holographic device may include a device that implements 360-degree stereoscopic images by recording and reproducing three-dimensional information using the light interference phenomenon that occurs when two laser lights, called holograms, meet.

[0042] For example, a public safety device may include an image relay device or imaging device that can be worn on the user's body.

[0043] For example, MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation. Examples include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0044] For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, curing, or preventing a disease. For example, a medical device may be a device used for diagnosing, treating, alleviating, or correcting an injury or damage. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying a structure or function. For example, a medical device may be a device used for the purpose of regulating pregnancy. For example, a medical device may include a therapeutic device, a driving device, an (in vitro) diagnostic device, a hearing aid, or a surgical device.

[0045] For example, a security device may be a device installed to prevent potential hazards and maintain safety. For example, a security device may be a camera, closed-circuit television (CCTV), recorder, or black box.

[0046] For example, a fintech device may be a device capable of providing financial services, such as mobile payments. For example, a fintech device may include a payment device or a point-of-sale system.

[0047] For example, a weather / environment device may include a device that monitors or predicts the weather / environment.

[0048] 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).

[0049] 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, device-to-device (D2D) communication), and base station-to-base station communication (150c) (e.g., relay, integrated access and backhaul (IAB)). 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.

[0050] AI is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0051] A robot can be defined as a machine that automatically processes or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making decisions, and performing actions on its own can be called an intelligent robot. Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with a drive unit, including an actuator or motor, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots include wheels, brakes, and propellers in their drive unit, enabling them to drive on the ground or fly in the air.

[0052] Autonomous driving refers to the technology of driving on one's own, while autonomous vehicles refer to vehicles that drive without, or with minimal, user intervention. For example, autonomous driving can include technologies such as lane keeping, automatic speed control like adaptive cruise control, autonomous driving along a set route, and autonomous driving based on a set destination. Vehicles encompass all types of vehicles: those with internal combustion engines, hybrid vehicles with both internal combustion engines and electric motors, and electric vehicles with only electric motors. These vehicles can include not only cars but also trains and motorcycles. Autonomous vehicles can be viewed as robots with autonomous driving capabilities.

[0053] Extended reality is a general term for VR, AR, and MR. VR technology provides real-world objects and backgrounds as CG images only, AR technology provides virtual CG images over images of real objects, and MR technology is a CG technology that mixes and combines virtual objects with the real world. MR technology is similar to AR in that it displays real and virtual objects together. However, there is a difference: while AR uses virtual objects to complement real objects, MR uses virtual and real objects equally.

[0054] NR supports multiple numerologies, or subcarrier spacing (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.

[0055] 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 NR systems, FR1 can mean the "sub-6GHz range," and FR2 can mean the "above 6GHz range," which can be referred to as millimeter wave (mmW).

[0056] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0057] 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).

[0058] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0059] 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 PAN (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.

[0060] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0061] 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.

[0062] 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).

[0063] 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).

[0064] 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).

[0065] 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.

[0066] 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.

[0067] 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).

[0068] 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).

[0069] 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).

[0070] 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 instruction codes, commands 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0075] 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.

[0076] 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 specification, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0077] 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).

[0078] 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.

[0079] In the implementation of the present specification, a UE can operate as a transmitter in the uplink (UL) and as a receiver in the downlink (DL). In the implementation of the present 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 the present specification or to control a transceiver (106) to perform UE operations according to the implementation of the present 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 the present specification or to control a transceiver (206) to perform base station operations according to the implementation of the present specification.

[0080] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0081] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0082] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0083] 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).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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).

[0088] 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).

[0089] 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.

[0090] 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).

[0091] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0092] 5GC (5G Core) may include various components, and in FIG. 5, some of them include AMF (Access and Mobility Management Function) (410), SMF (Session Management Function) (420), PCF (Policy Control Function) (430), UPF (User Plane Function) (440), AF (Application Function) (450), UDM (Unified Data Management) (460), and N3IWF (Non-3GPP (3rd Generation Partnership Project) Inter Working Function) (490).

[0093] The UE (100) is connected to a data network via UPF (440) through a Next Generation Radio Access Network (NG-RAN) including a gNB (20).

[0094] The UE (100) can also receive data services via untrusted non-3GPP access, such as a Wireless Local Area Network (WLAN). To connect the non-3GPP access to the core network, an N3IWF (490) may be deployed.

[0095] The illustrated N3IWF (490) performs the function of managing interworking between non-3GPP access and 5G system. When UE (100) is connected to non-3GPP access (e.g., WiFi, referred to as IEEE 801.11), UE (100) can be connected to 5G system through N3IWF (490). N3IWF (490) performs control signaling with AMF (410) and is connected to UPF (440) through N3 interface for data transmission.

[0096] The illustrated AMF (410) can manage access and mobility in a 5G system. The AMF (410) can perform functions to manage Non-Access Stratum (NAS) security. The AMF (410) can perform functions to handle mobility in the idle state.

[0097] The illustrated UPF (440) is a type of gateway through which user data is transmitted and received. The UPF node (440) can perform all or part of the user plane functions of the S-GW (Serving Gateway) and P-GW (Packet Data Network Gateway) of 4th generation mobile communications.

[0098] The UPF (440) acts as a boundary point between the next generation radio access network (NG-RAN) and the core network, and is an element that maintains a data path between the gNB (20) and the SMF (420). In addition, when the UE (100) moves across the area served by the gNB (20), the UPF (440) acts as a mobility anchor point. The UPF (440) can perform a function of handling PDUs. For mobility within the NG-RAN (Next Generation-Radio Access Network defined after 3GPP Release-15), the UPF can route packets. Additionally, the UPF (440) may also function as an anchor point for mobility with other 3GPP networks (RANs defined before 3GPP Release-15, e.g., UTRAN, E-UTRAN (Evolved-UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network)) or GERAN (GSM (Global System for Mobile Communication) / EDGE (Enhanced Data rates for Global Evolution) Radio Access Network). The UPF (440) may correspond to a termination point of a data interface toward a data network.

[0099] The illustrated PCF (430) is a node that controls the business operator's policy.

[0100] The illustrated AF (450) is a server for providing various services to the UE (100).

[0101] The illustrated UDM (460) is a type of server that manages subscriber information, such as the HSS (Home Subscriber Server) of 4th generation mobile communications. The UDM (460) stores and manages the subscriber information in a Unified Data Repository (UDR).

[0102] The illustrated SMF (420) can perform the function of allocating an IP (Internet Protocol) address of the UE. In addition, the SMF (420) can control a PDU (protocol data unit) session.

[0103] For reference, the drawing symbols for AMF (410), SMF (420), PCF (430), UPF (440), AF (450), UDM (460), N3IWF (490), gNB (20), or UE (100) may be omitted below.

[0104] 5G mobile communications support multiple numerologies, or subcarrier spacing (SCS), to support diverse 5G services. For example, a 15 kHz SCS supports wide areas in traditional cellular bands. A 30 kHz / 60 kHz SCS supports dense urban environments, lower latency, and wider carrier bandwidth. An SCS of 60 kHz or higher supports bandwidths greater than 24.25 GHz to overcome phase noise.

[0105] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0106] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0107] - AUSF (Authentication Server Function)

[0108] - AMF (Access and Mobility Management Function)

[0109] - DN (Data Network), 예를 들어 운영자 서비스, 인터넷 접속 또는 타사 서비스

[0110] - USDF (Unstructured Data Storage Function)

[0111] - NEF (Network Exposure Function)

[0112] - I-NEF (Intermediate NEF)

[0113] - NRF (Network Repository Function)

[0114] - NSSF (Network Slice Selection Function)

[0115] - PCF (Policy Control Function)

[0116] - SMF (Session Management Function)

[0117] - UDM (Unified Data Management)

[0118] - UDR (Unified Data Repository)

[0119] - UPF (User Plane Function)

[0120] - UCMF (UE radio Capability Management Function)

[0121] - AF (Application Function)

[0122] - UE (User Equipment)

[0123] - (R)AN ((Radio) Access Network)

[0124] - 5G-EIR (5G-Equipment Identity Register)

[0125] - NWDAF (Network Data Analytics Function)

[0126] - CHF (CHarging Function)

[0127] Additionally, the following network features may be considered:

[0128] - N3IWF (Non-3GPP InterWorking Function)

[0129] - TNGF (Trusted Non-3GPP Gateway Function)

[0130] - W-AGF (Wireline Access Gateway Function)

[0131] Figure 5 illustrates the 5G system architecture for a non-roaming case using a reference point representation showing how various network functions interact with each other.

[0132] In Figure 5, for clarity of the point-to-point diagram, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0133] 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.

[0134] The 5G system architecture includes the following benchmarks:

[0135] - N1: Reference point between UE and AMF.

[0136] - N2: Reference point between (R)AN and AMF.

[0137] - N3: Reference point between (R)AN and UPF.

[0138] - N4: Reference point between SMF and UPF.

[0139] - N6: Reference point between UPF and data network.

[0140] - N9: Reference point between two UPFs.

[0141] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0142] - N5: Reference point between PCF and AF.

[0143] - N7: Reference point between SMF and PCF.

[0144] - N8: Reference point between UDM and AMF.

[0145] - N10: Reference point between UDM and SMF.

[0146] - N11: Reference point between AMF and SMF.

[0147] - N12: Reference point between AMF and AUSF.

[0148] - N13: Reference point between UDM and AUSF.

[0149] - N14: Reference point between two AMFs.

[0150] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0151] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0152] - N22: Reference point between AMF and NSSF.

[0153] In some cases, two NFs may need to be interconnected to serve a UE.

[0154] <Non-Terrestrial Networks >

[0155] NTN (Non-Terrestrial Network) refers to a network or network segment that uses RF resources mounted on satellites (or UAS platforms).

[0156] There are two common scenarios for NTNs that provide access to user equipment: transparent payload and regenerative payload.

[0157] NTNs are typically characterized by the following elements:

[0158] - One or more sat-gateways connecting the NTN to the public data network.

[0159] - GEO satellites are served by one or more satellite gateways deployed across the satellite's target coverage area (e.g., regional or continental coverage). We assume that a UE in a cell is served by only one sat-gateway.

[0160] Non-GEO satellites that provide continuous service from one or more satellite gateways at a time. The system ensures service and feeder link continuity between consecutively serving satellite gateways with sufficient time duration to allow for mobile anchoring and handover.

[0161] - Feeder link or wireless link between the satellite gateway and the satellite (or UAS platform).

[0162] - Service link or wireless link between user equipment and satellite (or UAS platform).

[0163] A satellite (or UAS platform) capable of implementing transparent or regenerative (including onboard processing) payloads. The satellite (or UAS platform) typically generates multiple beams for a designated service area, depending on its field of view. The beam's footprint is typically elliptical. The satellite's (or UAS platform's) field of view varies depending on the onboard antenna diagram and minimum elevation angle.

[0164] - Transparent payload: Radio frequency filtering, frequency conversion, and amplification. Therefore, the waveform signal repeated by the payload remains unchanged.

[0165] Regenerative payload: Radio frequency filtering, frequency conversion and amplification, demodulation / decoding, switching and / or routing, and coding / modulation. This is essentially equivalent to embedding all or part of a base station function (e.g., gNB) on a satellite (or UAS platform).

[0166] - Optionally, for satellite constellations, inter-satellite link (ISL) is available. This requires a regenerative payload on the satellite. ISL can operate in RF or wideband.

[0167] - User equipment is serviced by satellites (or UAS platforms) within the target service area.

[0168] For transparent satellites, the satellite amplifies signals transmitted from a ground station (gNB-NTN gateway) and transmits them to the terminal. Regenerative satellites, in addition to signal amplification, perform ground station functions such as routing, coding, modulation, and decoding / demodulation. NTN terminals have GPS capabilities and periodically receive location, time, and velocity information from NTN satellites.

[0169] Describes S&F operation in relation to communications via satellite.

[0170] <S&F (Store and Forward)>

[0171] In satellite-enabled 5G systems, S&F satellite operation is intended to provide delay-tolerant communication services to UEs that are within satellite coverage and have intermittent / transient satellite connectivity (e.g., when the satellite is not connected via a feeder link or is not connected to a terrestrial network via ISL).

[0172] Figure 6 shows an example of basic satellite operation.

[0173] Figure 7 shows an example of S&F satellite operation.

[0174] Figures 6 and 7 illustrate examples of “S&F satellite operation” in contrast to current assumptions about “normal / default satellite operation” for a satellite-enabled 5G system.

[0175] A service link may be a link between a terminal and a satellite, and a feeder link may be a link between a satellite and a base station.

[0176] - In "Normal / Default Satellite Operation" mode, for signaling and data traffic exchange between a UE with satellite access and a remote terrestrial network, the service link and feeder link must be activated simultaneously. Therefore, a continuous end-to-end connection path exists between the UE, satellite, and terrestrial network when the UE interacts with the satellite via the service link.

[0177] - In contrast, in the "S&F satellite operation" mode, the end-to-end exchange of signal / data traffic is now handled as a combination of two non-temporally simultaneous steps (step A and step B). In step A, signal / data exchange between the UE and the satellite is performed. This can be done even if the satellite is not simultaneously connected to the terrestrial network (i.e., the satellite can operate the service link without an active feeder link connection). In step B, a connection is established between the satellite and the terrestrial network, allowing communication between the satellite and the terrestrial network. Thus, the satellite moves from being connected to the UE in step A to being connected to the terrestrial network in step B.

[0178] The concept of "S&F" services is widely used in delay-tolerant and disruption-tolerant networking. In the 3GPP context, a service that can be integrated into an S&F service is SMS, which does not require end-to-end connectivity between endpoints (e.g., one endpoint may be a UE and another endpoint may be an application server). However, connectivity is only required between the endpoints and the SMSC, which acts as an intermediate node responsible for storage and dependency management.

[0179] S&F satellite operation support may be particularly suitable for providing delay-tolerant / non-real-time IoT satellite services using NGSO satellites.

[0180] Transparent and regenerative payloads are:

[0181] - Transparent payload: Electromagnetic waves transmitted from the Earth's surface are converted into electrical signals via the satellite receiving antenna. These signals are channel-filtered and amplified by a low-noise amplifier (LNA). The signals are then frequency-converted. Finally, a high-power amplifier (HPA) transmits the signals to the transmitting antenna, which generates regenerated electromagnetic waves directed toward the Earth's surface where the receiving station is located.

[0182] Regenerative payload: An onboard processor (OBP) is inserted between the LNA and the HPA. This OBP can convert the air interface between the uplink (from Earth to the satellite) and downlink (from the satellite to Earth). This allows it to correct erroneous bits or packets before retransmission, or to route packets between beams. Ultimately, thanks to the OBP (including all functions connected to the gNB CU or DU or CN), all network functions can be implemented at the expense of power and mass.

[0183] To support S&F functionality, a regenerative satellite (a satellite that can act as a ground base station) may be required, rather than a transparent satellite that simply forwards the terminal's signal.

[0184] To support S&F functionality, a split MME architecture may be proposed.

[0185] The MME (or AMF) function can be divided into MME-onboard (or AMF-onboard) and MME-ground (or AMF-ground). MME-onboard is the MME part mounted on the satellite. MME-ground is the MME part located on the terrestrial network and operates via interfaces outside the scope of 3GPP.

[0186] MO data is stored in the MME-onboard when the service link is available and the feeder link is unavailable, and can be transmitted to the ground when the feeder link becomes available.

[0187] MT data is stored in the MME-ground or S-GW when the feeder link is unavailable, and can be transmitted to the MME-onboard when the feeder link becomes available. MT data is stored in the MME-onboard when the feeder link is available and the service link is unavailable, and can be transmitted to the UE when the service link becomes available. All types of data traffic (e.g., IP, etc.) can be supported and transmitted using the existing user plane and control plane procedures defined in the EPS.

[0188] The UE may be aware that the satellite supports S&F mode.

[0189] Operators can choose to deploy either a split MME architecture, where the eNB and MME (MME-onboard) are onboard the satellite to support the satellite's S&F operations, and the MME-ground is located on the ground, or a full CN architecture, where all core network functions, including the eNB, are onboard the satellite.

[0190] In a split MME architecture, data from a UE can be transmitted and received to the Control Plane (CP) using Control Plane (CP) CIoT EPS Optimisation, or data from a UE can be transmitted and received to the UP using the general User Plane (UP) or UP CIoT EPS Optimisation.

[0191] For MT (Mobile Terminated) (DL) data transmitted to a terminal through S&F operation, it may be efficient for the MME to utilize the orbital information of satellites to select the satellite with the shortest delay in transmission to the terminal and transmit the data to that satellite.

[0192] When using CP CIoT and buffering data in the MME-ground, the MME-ground can buffer DL data transmitted from the S-GW. The MME-ground selects the satellite with the lowest delay for transmission to the terminal and, when a feeder link is established with the satellite, forwards the data to the satellite's MME-onboard. The satellite can then buffer and store the received data. Once the satellite covers the terminal's area and a service link is established with the terminal, the satellite can forward the buffered data to the terminal.

[0193] Even if the S11-U interface resource is created between the MME-ground and the S-GW (Serving-GW) for MO (Mobile Originated) data and the S-GW transmits DL data to the MME-ground, if the MME determines that the satellite currently connected to the feeder link is not suitable for transmitting data to the terminal (if transmitting to another satellite is possible to transmit to the terminal faster), it may not transmit the data to the satellite currently connected to the feeder link and may additionally buffer the DL data (until it is connected to another suitable satellite via feeder link).

[0194] However, even when CP CIoT is used, if resources are created through the S11-U interface between the MME-ground and the S-GW due to UL data generation when the S-GW buffers data instead of the MME-ground, the data being buffered in the S-GW or the DL data generated / received in the S-GW can be directly transmitted to the MME-onboard. Alternatively, when data is transmitted to the UP for the S&F operation of the satellite, the UP uses the S1-U interface between the S-GW and the eNB, so the MME cannot transmit the data, and the S-GW may directly transmit the data to the eNB.

[0195] In both cases, the feeder link is connected to the satellite storing the MO data for MO data transmission, allowing the satellite to transmit user data to the S-GW. If the S-GW already has buffered data or DL ​​data is generated, the S-GW can transmit the MT data to the satellite currently connected to the feeder link. The satellite can then store (buffer) the data. If the satellite covers the area where the terminal is located, the satellite can transmit the buffered data to the terminal.

[0196] Since the S-GW does not know the satellite's orbital information or whether it has a feeder link, the satellite connected to the feeder link for MO data transmission may not be suitable for transmitting MT data. (There may be other satellites that can deliver MT data to the UE more quickly.) The figure below illustrates an example of this situation.

[0197] Figure 8 shows an example of operation at time T1 in S&F satellite operation.

[0198] The satellite can be equipped with eNB and MME-onboard.

[0199] The satellite orbits along an arrow-shaped orbit.

[0200] There may be no ISL (Inter Satellite Link) between satellites.

[0201] On the ground, there may be an MME-ground and an S-GW that connect to the satellite's MME-onboard.

[0202] At T1, satellite 1 can be connected to a feeder link through a gateway on the ground.

[0203] When downlink (DL) data to UE1 is generated or when S-GW buffers DL data to UE1, MME can determine whether satellite 1 is a suitable satellite to transmit DL data based on orbital information, etc.

[0204] If satellite 1 is determined to be a suitable satellite for transmitting DL data, an S1-U interface resource is created between the eNB and S-GW of satellite 1 so that DL data can be transmitted to satellite 1.

[0205] Satellite 1 can store the received DL data.

[0206] Figure 9 shows an example of operation at time T2 in S&F satellite operation.

[0207] At T2, satellite 1 can move along its orbit to service UE1's area. Satellite 1 can then transmit the DL data it was storing (buffering) to UE1.

[0208] At this time, UE1 can generate uplink (UL) data and transmit the UL data to satellite 1. Satellite 1 can store (buffer) the UL data of UE1.

[0209] At this point, if DL data is generated at the P-GW, the S-GW can notify the MME-ground of the DL data generation. Based on satellite orbital information and other factors, the MME-ground can determine that there is currently no feeder link connected to a satellite suitable for transmitting DL data to UE1. Based on this, the MME-ground can notify the S-GW to additionally buffer the DL data.

[0210] Figure 10 shows an example of operation at time T3 in S&F satellite operation.

[0211] At T3, as the feeder link between satellite 1 and the ground gateway is connected, MME-ground can create S1-U interface resources between the satellite's eNB and the S-GW to transfer the UL data of UE1 that was stored at T2 to the S-GW.

[0212] As resources are created between the eNB and the S-GW, the S-GW can transmit DL data that was buffered by conventional operation to the eNB of satellite 1.

[0213] However, as shown in Figure 10, satellite 1 must complete one more orbit to service UE1's area. This may result in excessively long transmission delays.

[0214] Therefore, to reduce delay, DL data can be transmitted to a satellite other than satellite 1 (e.g., satellite 2 that will be connected after time T3).

[0215] That is, when a feeder link with a satellite is connected due to UL data, etc., the S-GW unconditionally transmits DL data, which may cause a delay.

[0216] Therefore, even when UP resources are created, the S-GW can buffer DL data rather than immediately transmitting it. Once a suitable satellite and feeder link are connected, the S-GW can transmit DL data to the satellite.

[0217] In this specification, a method for efficiently transmitting MT data in a split MME structure for S&F operation can be proposed.

[0218] The method proposed in this specification may be composed of a combination of one or more of the multiple operations / configurations / steps described below.

[0219] The procedures and / or messages in the method proposed in this specification may use conventional procedures / messages, may use conventional procedures / messages by extending them, or may define and use new procedures / messages.

[0220] In this specification, MT data, DL data, downlink data, MT traffic, and DL traffic are used interchangeably.

[0221] In this specification, MO data, UL data, uplink data, MO traffic, and UL traffic are used interchangeably.

[0222] In this specification, UE (User Equipment) and terminal are used interchangeably.

[0223] This specification mainly describes the proposed content.

[0224] This specification assumes a structure in which an eNB, gNB, NG-RAN, or base station is mounted on a satellite.

[0225] The satellite in this specification may be equipped with an MME (MME-onboard).

[0226] In this specification, satellites are assumed to be LEO or MEO satellites, but other types of satellites are not excluded.

[0227] This specification focuses on the components and interfaces of EPS, but these can be applied to 5GS in the same way or expanded / modified to suit 5GS.

[0228] In this specification, MME may be AMF.

[0229] In this specification, an eNB may be an NG-RAN (gNB).

[0230] In this specification, HSS may be UDM.

[0231] In this specification, Attach may be Registration.

[0232] In this specification, a TAU may be a Mobility Registration Update.

[0233] In this specification, MME-ground may be AMF-ground.

[0234] In this specification, MME-onboard may be AMF-onboard.

[0235] In this specification, the S-GW may be an SMF (SMF / UPF).

[0236] In a split MME (AMF) architecture, a satellite can be equipped with an eNB and an MME-onboard (AMF-onboard). The satellite's MME-onboard (AMF-onboard) can be connected to the ground MME-ground (AMF-ground).

[0237] The interface between MME-onboard (AMF-onboard) and MME-ground is assumed to operate as an internal implementation. Internal implementation may refer to a non-standardized interface or interaction.

[0238] The terminal in this specification may be a terminal supporting the S&F function.

[0239] The method proposed in this specification can be applied to a terminal supporting the &F function.

[0240] In the method proposed in this specification, the MME (AMF) can commonly know that the terminal supports the S&F function.

[0241] For example, during the attach (or TAU) process, the UE may indicate its capability to support S&F mode, and the MME may indicate in the attach (or TAU) acceptance message that it operates in S&F mode.

[0242] It is assumed that the MME has provisioned information regarding the terminal's orbit, coverage, and feeder link availability. For example, provisioning can be performed through O&M. Alternatively, the MME can receive and store information from the AF or a new NF.

[0243] It is assumed that the terminal is attached in S&F mode.

[0244] When data is transmitted and received through the user plane or when data is transmitted and received using CP CIoT, it is assumed that user data is not buffered in the MME (-ground), but is buffered in the S-GW.

[0245] In this specification, embodiments applicable to a satellite with a split MME structure and an EPC network supporting the same when generating resources for data transmission may be proposed.

[0246] The proposed method can prevent unintended MT data transmission (perform, resume) due to MO data.

[0247] I. First Example

[0248] According to the first embodiment, the MME can give a separate indication to the S-GW.

[0249] When uplink data transmission creates UP resources between the eNB and the S-GW, the MME may send a Modify Bearer Request to the S-GW with an indication not to transmit downlink data.

[0250] The indication transmitted from the MME to the S-GW can be defined in the following form, but may also be defined in other forms:

[0251] - 'DL data should not be sent'

[0252] - 'DL data is not allowed'

[0253] - 'UL data only'

[0254] - 'MT data is not allowed'

[0255] - 'MO data only'

[0256] - 'No service link'

[0257] - 'feeder link only'

[0258] - 'DL data delivery should be suspended'

[0259] The above indication may be included in the Indication IE (one of the spare bits of the Indication IE) as an additional indication, such as "An indication that DL data should not be sent", in the Indication Flags included in the Modify Bearer Request.

[0260] This may mean using one of the spare bits as the additional indication.

[0261] Instead of a Modify Bearer Request, a Modify Access Bearer Request may be used, which contains bearer context information for all PDN connections connected to the UE. In this case, a new IE indicating this may be added within the Modify Access Bearer Request.

[0262] Alternatively, the MME may request the S-GW not to transmit DL data for the bearer by including a new IE as an indication in the "Bearer Contexts to be modified" IE contained in the Modify Bearer Request or Modify Access Bearer Request.

[0263] The MME can additionally include in the message it transmits to the S-GW the time required for a suitable satellite and feeder link to be connected for MT data transmission to the terminal. Based on this, the S-GW can attempt to transmit MT data to the MME after the specified time has elapsed.

[0264] When the S-GW receives the aforementioned indication, the S-GW may decide not to send DL data even if UP resources for DL ​​data transmission are created.

[0265] Afterwards, when a satellite and feeder link suitable for MT data transmission to the terminal are connected, the MME can transmit a Modify Bearer Request to the S-GW that does not include the aforementioned indication (indication not to send downlink data) so that DL data can be transmitted normally as before. Based on this, UP resources are created, and the S-GW can transmit DL data to the connected satellite.

[0266] Alternatively, the MME may provide an indication / information to the S-GW to notify it to perform (resume) transmission of DL data.

[0267] Figures 11, 12 and 13 illustrate examples of operation in a split MME architecture according to the disclosure of this specification.

[0268] Figures 11, 12 and 13 show examples of flowcharts in which the first embodiment is applied in data transmission via User Plane CIoT EPS Optimisation.

[0269] The service link may be connected, but the feeder link may not be connected.

[0270] The above service link may be a link between satellite 1 and a terminal, and the above feeder link may be a link between a ground gateway (ground network) and satellite 1.

[0271] The eNB and MME-onboard (or MME-ground) of Satellite 1 and Satellite 2 can store bearer context related to UE context through the Connection Suspend Procedure.

[0272] 0) step 0

[0273] Uplink data may be generated from the terminal.

[0274] The terminal can connect to satellite 1 and transmit the terminal's uplink data to satellite 1.

[0275] Satellite 1 can store uplink data.

[0276] 1) Step 1

[0277] Based on the occurrence of downlink data, the PDN GW can forward the downlink data to the S-GW.

[0278] 2a) step 2a

[0279] The S-GW can notify the serving MME (MME-ground) of the terminal that there is downlink data to be sent to the terminal through Downlink Data Notification.

[0280] 2b) step 2b

[0281] There may be no inter-satellite feeder link connection between MME-ground and the current terminal to transmit data. Based on this, MME-ground can send the downlink buffering duration to the S-GW along with a DL Data Notification ACK.

[0282] The downlink buffering duration can be determined based on the time until the feeder link between the satellite that will transmit the downlink data to the terminal and the ground network (ground gateway) is connected.

[0283] Based on the downlink buffering duration, the S-GW may additionally buffer downlink data. The S-GW may not send additional downlink data notifications until the downlink data buffer expiration time expires.

[0284] As the satellite moves, the service link between Satellite 1 and the terminal may be disconnected.

[0285] As the satellite moves, a feeder link can be established between Satellite 1 and MME-ground (ground gateway).

[0286] 3a) Step 3a

[0287] Satellite 1's MME-onboard can notify Satellite 1's eNB that the feeder link is connected via an S1-AP message (e.g., a new IE in the MME Configuration Update or a new S1-AP message). Step 3a can be omitted. That is, Satellite 1's eNB can otherwise recognize (or predict) that the feeder link is connected.

[0288] 3b) step 3b

[0289] Satellite 1's eNB can determine that the feeder link is connected based on the message in step 3a.

[0290] Alternatively, the eNB of satellite 1 can predict that a feeder link is connected based on satellite orbit information.

[0291] An SCTP connection can be established between the eNB of Satellite 1 and the MME on the N2 interface. Based on this, the eNB of Satellite 1 can request the MME-onboard to resume the bearer context associated with the UE context through an S1-AP message (UE Context Resume Request).

[0292] When the eNB of satellite 1 requests the MME-onboard to resume RRC connection through an S1-AP message (RRC Connection Resume Request), the eNB of satellite 1 may also transmit an indication indicating whether i) the request is by an RRC Connection Resume Request of the terminal or ii) the request is by buffered data transmission by S&F operation.

[0293] 4) Step 4

[0294] Satellite 1's MME-onboard and MME-ground can exchange necessary information based on their internal implementation. At this point, MME-ground (the MME-ground serving the terminal) can recognize that it needs UP resources with the core network.

[0295] Satellite 1's MME-onboard can inform MME-ground of the TEID information of Satellite 1's eNB stored in the terminal's bearer context.

[0296] 5) Step 5

[0297] MME-ground can decide whether to transmit the downlink data of step 1 to satellite 1.

[0298] The above decision can be made based on the last known location information of the terminal, mobility information of the terminal (e.g., whether it is a stationary terminal), orbital information of the satellite, coverage information, feeder link availability information, indication of step 3b (indication indicating that the request is for buffered data transmission by S&F operation) (transmitted from MME-onboard to MME-ground in step 4), etc.

[0299] MME-ground may determine that it is more efficient to transmit downlink data to another satellite (e.g., satellite 2) to which a feeder link will be connected later, rather than to satellite 1. Based on this, MME-ground may decide not to transmit downlink data to satellite 1, to which the feeder link is currently connected. Based on this, the S-GW may also decide not to transmit downlink data to satellite 1.

[0300] Even in this case, if the S1-AP message (RRC Connection Resume Request) transmitted by the eNB of satellite 1 in step 3b includes an indication (=an indication indicating that the request is by the terminal's RRC Connection Resume Request) (or if the S1-AP message is transmitted to the MME-onboard together with the indication), the MME-onboard / MME-ground can decide to normally transmit downlink data to satellite 1. Based on this, the S-GW can transmit downlink data to satellite 1.

[0301] Based on the terminal's location information, terminal mobility information (e.g., whether it is a stationary terminal), satellite orbit information, coverage information, and feeder link availability information, the MME-ground can determine the optimal satellite to transmit downlink data. The optimal satellite may not currently have a feeder link connected. Transmitting downlink data to the optimal satellite may be the most delay-reducing method. The MME-ground can decide not to transmit downlink data to Satellite 1, which is currently connected to a feeder link. Based on this, the S-GW can also decide not to transmit downlink data to Satellite 1.

[0302] 6a) step 6a

[0303] The MME-ground may send a user plane context modification request for the UE to the S-GW. The user plane context modification request may be a Modify Bearer Request.

[0304] The MME-ground can send a Modify Bearer Request to the S-GW. Based on this, UP resources can be created in the S-GW and eNB.

[0305] The Modify Bearer Request may include information related to Satellite 1. For example, the Modify Bearer Request may include the TEID and / or the IP address of Satellite 1. The TEID may be information related to Satellite 1.

[0306] If MME-ground decides in step 5 not to transmit downlink data to satellite 1, the Modify Bearer Request transmitted to S-GW may include an indication not to transmit downlink data.

[0307] At this time, the MME-ground can include information about the time it takes to establish a feeder link with a satellite suitable for downlink data transmission to the terminal in the Modify Bearer Request. Based on this, the S-GW can attempt to transmit downlink data to the MME-ground after the above time has elapsed.

[0308] 6b) step 6b

[0309] If the Modify Bearer Request includes an indication not to transmit downlink data, the S-GW may not transmit downlink data to the UP.

[0310] The S-GW may send a Modify Bearer Response to the MME-ground in response to the request in step 6a. The Modify Bearer Response may include a Tunnel Endpoint Identifier (TEID) for uplink data transmission.

[0311] 7) Step 7

[0312] MME-ground can transmit information of Modify Bearer Response received from S-GW through internal interface to MME-onboard of satellite 1.

[0313] 8) Step 8

[0314] The MME-onboard of Satellite 1 can inform the eNB of Satellite 1 that the bearer context associated with the UE context has been resumed via an S1-AP message (UE Context Resume Response).

[0315] Through this, an S1-U bearer can be created.

[0316] 9) Step 9

[0317] Based on the bearer context information related to the UE context stored by the eNB of satellite 1 and the generated S1-U bearer, the eNB of satellite 1 can transmit uplink data to the S-GW.

[0318] If the S-GW receives an indication from the MME-ground in step 6a indicating not to transmit downlink data, the S-GW may not transmit downlink data to satellite 1 even if there is downlink data being buffered.

[0319] While Satellite 1 and the feeder link are connected, even if the S-GW receives additional downlink data for the terminal from the PDN GW, the S-GW may not forward the downlink data.

[0320] 10) Step 10

[0321] MME-ground can anticipate that the feeder link with satellite 1 will be lost based on the satellite's orbital information and notify MME-onboard of this.

[0322] 11a) Step 11a

[0323] The MME-onboard can notify the eNB that the feeder link will be disconnected via an S1-AP message (e.g. a new IE in the MME Configuration Update or a new S1-AP message).

[0324] 11b) step 11b

[0325] Satellite 1's eNB can anticipate a feeder link disconnection based on the message in step 11a (or satellite orbit information stored in the eNB). Based on this, Satellite 1's eNB can trigger a connection suspend procedure to free up terminal resources.

[0326] 12-14) Step 12 - Step 14

[0327] The MME-onboard can notify the MME-ground through its internal interface that a connection suspension is required. Based on this, the MME-ground can release resources through a Release Access Bearer Request / Response with the S-GW.

[0328] The MME-ground may also send a Release Access Bearer Request to the S-GW, including information about the time required for a suitable satellite and feeder link for downlink data transmission to be connected (step 13). Based on this, the S-GW may attempt to transmit downlink data to the MME-ground after the specified time has elapsed.

[0329] 15) Step 15

[0330] The MME-onboard may forward the S1-AP message received through the internal interface with the MME-ground to the eNB. The S1-AP message may include a UE Context Suspend Response. The UE Context Suspend Response may include information indicating that the bearer context associated with the UE context has been suspended.

[0331] As the satellite moves, a feeder link can be established between Satellite 2 and the ground network.

[0332] Satellite 2's MME-onboard can notify Satellite 2's eNB that the feeder link is connected.

[0333] 16) Step 16a - Step 16b

[0334] The S-GW can receive the time information for satellite 2 connection through steps 2b, 6a, and 13 (or other methods). Based on this, the S-GW can send a downlink data notification (DL Data Notification) to the MME-ground. The MME-ground can then send an ACK to the S-GW.

[0335] 17) Step 17

[0336] MME-ground can decide whether to transmit the downlink data of step 1 to satellite 2.

[0337] The above decision may be made based on the last known location information of the terminal, mobility information of the terminal (e.g., whether it is a stationary terminal), orbital information of the satellite, coverage information, feeder link availability information, etc.

[0338] MME-ground may determine that it is efficient to transmit the downlink data to satellite 2. Based on this, MME-ground may decide to transmit the downlink data of step 1 to satellite 2.

[0339] 18) Step 18

[0340] Satellite 2's MME-ground can notify MME-onboard via its internal interface that UP generation is required for downlink data transmission.

[0341] 19) Step 19

[0342] The eNB of Satellite 2 can request the MME-onboard to resume the bearer context related to the UE context via the S1-AP message (UE Context Resume Request).

[0343] 20) Step 20

[0344] Satellite 2's MME-onboard can notify MME-ground to resume the UE context and bearer context through its internal interface.

[0345] Satellite 2's MME-onboard can inform MME-ground of the TEID information of Satellite 1's eNB stored in the terminal's bearer context.

[0346] 21a) Step 21a

[0347] The MME-ground may send a user plane context modification request for the UE to the S-GW. The user plane context modification request may be a Modify Bearer Request.

[0348] The MME-ground can send a Modify Bearer Request to the S-GW. Based on this, UP resources can be created.

[0349] The Modify Bearer Request may include information related to Satellite 2. For example, the Modify Bearer Request may include the TEID and / or the IP address of Satellite 2. The TEID may be information related to Satellite 2.

[0350] Based on the decision in step 17, the Modify Bearer Request may not include an indication not to send downlink data.

[0351] Alternatively, the MME may provide an indication / information to the S-GW to initiate (resume) transmission of downlink data.

[0352] 21b) step 21b

[0353] The S-GW may send a Modify Bearer Response to the MME-ground in response to the request in step 21a. The Modify Bearer Response may include a Tunnel Endpoint Identifier (TEID) for uplink data transmission.

[0354] 22) Step 22

[0355] MME-ground can transmit information (including TEID of S-GW) of Modify Bearer Response received from S-GW through internal interface to MME-onboard of Satellite 2.

[0356] 23) Step 23

[0357] Satellite 2's MME-onboard can transmit S-GW's TEID information and information for UP generation to the eNB via the S1-AP message.

[0358] 24) Step 24

[0359] The S-GW can forward the buffered downlink data to the eNB of Satellite 2 via the S1-U bearer.

[0360] The S-GW may forward the buffered downlink data to the eNB of satellite 2 based on the TEID and / or the IP address of satellite 2 received in step 21a.

[0361] While the feeder link is connected to Satellite 2, if the S-GW receives additional downlink data for the terminal from the PDN GW, the S-GW can forward the downlink data to the eNB of Satellite 2.

[0362] 25) Step 25

[0363] Satellite 2's eNB can transmit uplink data from the terminal to the S-GW through the generated S1-U bearer.

[0364] The above-described operations can be similarly applied even when using general UP resources rather than UP CIoT EPS Optimization.

[0365] When CP CIoT EPS Optimisation is used and

[0366] i) MME-ground receives a UP resource creation request from eNB through MME-onboard, or

[0367] ii) When MME-ground receives downlink data notification from S-GW and S11-U UP resource creation between MME and S-GW is required,

[0368] Based on satellite orbit information, etc., the MME-ground may determine that the satellite currently connected to the feeder link is not suitable for transmitting downlink data. In this case, the MME-ground may include an indication not to transmit downlink data in the Modify Bearer Request transmitted to the S-GW. In addition, the MME may transmit the Modify Bearer Request including information about the time until a satellite suitable for downlink data transmission to the terminal and the feeder link are connected. In this way, when CP CIoT EPS Optimization is used and i (or ii) is applicable, it may operate similarly to the example of UP CIoT EPS Optimization described above.

[0369] For 5GS, UP resources can be created through the N3 interface between the UPF and the NG-RAN. When a satellite and a feeder link are connected and a Namf_MT_EnableUEReachability Request or Namf_Communication_N1N2MessageTransfer is received due to downlink data, or a request for UP resource creation is received by the gNB, the AMF-ground can determine whether to create UP resources for the downlink by checking / determining whether it is efficient to transmit downlink data to the satellite based on the satellite's orbit information, coverage information, and feeder link availability information when creating SMF and UP resources.

[0370] When AMF-ground transmits the Nsmf_PDUSession_UpdateSMContext Request message to create UP resources between the gNB and the UPF due to uplink data transmission, AMF-ground may determine that the satellite currently connected to the feeder link is not a suitable satellite for transmitting downlink data based on the satellite's orbital information, etc. Based on this, AMF-ground may transmit the Nsmf_PDUSession_UpdateSMContext Request message with an indication indicating that downlink data should not be transmitted.

[0371] The aforementioned indication may be added to Type 'SmContextUpdateData' in Clause 6.1.6.2.4 of TS 29.502 v18.7.0 with a new IE.

[0372] Upon receiving the indication, the SMF may request the UPF to not update the N4 rules related to downlink data for the terminal in the N4 Modification Request. Based on this, the UPF may not transmit downlink data.

[0373] AMF-ground can send to SMF the Nsmf_PDUSession_UpdateSMContext Request including information about the time until a suitable satellite and feeder link for downlink data transmission to the terminal are connected. Even when disconnecting from a satellite connected to a feeder link, AMF-ground can send to SMF the Nsmf_PDUSession_UpdateSMContext Request including information about the time until a suitable satellite and feeder link for downlink data transmission to the terminal are connected.

[0374] Based on the information about the aforementioned time, the SMF may attempt to transmit downlink data to AMF-ground after the said time has elapsed.

[0375] Afterwards, when a satellite and feeder link suitable for downlink data transmission are connected, and AMF-ground receives Namf_MT_EnableUEReachability Request / Namf_Communication_N1N2MessageTransfer by downlink data or a request for UP resource creation by gNB, AMF-ground can send Nsmf_PDUSession_UpdateSMContext Request message to SMF without including an indication not to send downlink data.

[0376] Alternatively, after a suitable satellite and feeder link for downlink data transmission are connected, and AMF-ground receives Namf_MT_EnableUEReachability Request / Namf_Communication_N1N2MessageTransfer for downlink data or a request for UP resource creation by gNB, AMF may provide an indication / information to SMF to perform (resume) transmission of downlink data.

[0377] Based on this, the SMF can update the N4 rules for uplink / downlink data transmission to the UPF. Based on this, both uplink and downlink data can be transmitted.

[0378] Figures 14, 15, 16 and 17 illustrate examples of operation in a split AMF architecture according to the disclosure of this specification.

[0379] Figures 14, 15, 16 and 17 show examples in which the first embodiment is applied in 5GS.

[0380] The service link may be connected, but the feeder link may not be connected.

[0381] The above service link may be a link between satellite 1 and a terminal, and the above feeder link may be a link between a ground gateway (ground network) and satellite 1.

[0382] The NG-RAN and AMF-onboard (or AMF-ground) of Satellite 1 and Satellite 2 can store bearer contexts related to UE contexts through the Connection Inactive Procedure (4.8.1.1 of TS 23.502 v18.7.0) or the Connection Suspend Procedure (4.8.1.2 of TS 23.502 v18.7.0).

[0383] 0) step 0

[0384] Uplink data may be generated from the terminal.

[0385] The terminal can connect to satellite 1 and transmit the terminal's uplink data to satellite 1.

[0386] Satellite 1 can store uplink data.

[0387] 1) Step 1

[0388] Based on the occurrence of downlink data, the downlink data can be passed to the UPF.

[0389] 2a) step 2a

[0390] UPF can notify the SMF of a terminal that there is downlink data to be sent to the terminal through Downlink Data Notification.

[0391] 2b) step 2b

[0392] SMF can send an ACK for Downlink Data Notification to UPF.

[0393] 3a) Step 3a

[0394] If SMF / UPF is configured to buffer data, SMF can check the transmittable state of data from AMF.

[0395] SMF can check the transferability of data by sending a Namf_MT_EnableUEReachability request to AMF.

[0396] 3b) Step 3b

[0397] There may not be a feeder link connection between the satellite and AMF-ground to transmit data to the current terminal.

[0398] Therefore, if SMF previously provided an Extended Buffering Support Indication to AMF, AMF-ground can include an Estimated Maximum Wait time in its response to the Namf_MT_EnableUEReachability request and send it to SMF, based on the time when satellite 1 will be connected to the ground gateway.

[0399] The Estimated Maximum Wait time can be determined based on the time it takes for a satellite to connect to transmit downlink data.

[0400] 4) Step 4

[0401] SMF can determine the extended buffering time based on the estimated maximum wait time.

[0402] Additionally, the SMF may request the UPF to buffer data for an extended buffering time determined by the SMF while sending a failure indication to the UPF.

[0403] As the satellite moves, the service link between Satellite 1 and the terminal may be disconnected.

[0404] As the satellite moves, a feeder link can be established between Satellite 1 and AMF-ground (ground gateway).

[0405] 5a) Step 5a

[0406] Satellite 1's AMF-onboard can notify Satellite 1's NG-RAN that the feeder link is connected via an NG-AP message (e.g., a new IE in AMF Configuration Update or a new NG-AP message). Step 5a can be omitted. That is, Satellite 1's NG-RAN can otherwise recognize (or predict) that the feeder link is connected.

[0407] 5b) step 5b

[0408] Satellite 1's NG-RAN can determine that the feeder link is connected based on the message in step 5a.

[0409] Alternatively, the NG-RAN of satellite 1 can predict that a feeder link is connected based on satellite orbit information.

[0410] An SCTP connection can be established on the NG interface between Satellite 1's NG-RAN and AMF. Based on this, Satellite 1's NG-RAN can request AMF-onboard to resume QoS flows associated with the UE context via an NG-AP message (e.g., N2 Resume Request).

[0411] When the NG-RAN of satellite 1 transmits an NG-AP message (N2 Resume request) to the AMF-onboard, the NG-RAN of satellite 1 may also transmit an indication indicating whether i) the request is by an RRC Connection Resume Request of the terminal or ii) the request is by buffered data transmission by an S&F operation.

[0412] 6) Step 6

[0413] Satellite 1's AMF-onbard and AMF-ground can exchange necessary information based on their internal implementation. At this time, AMF-ground (the AMF-ground serving the terminal) can recognize that it needs UP resources with the core network.

[0414] 7) Step 7

[0415] AMF-ground can decide whether to transmit the downlink data of step 1 to satellite 1.

[0416] The above decision can be made based on the last known location information of the terminal, mobility information of the terminal (e.g. whether it is a stationary terminal), orbital information of the satellite, coverage information, feeder link availability information, indication of step 5b (indication indicating that the request is by buffered data transmission by S&F operation) (transmitted from AMF-onboard to AMF-ground in step 6), etc.

[0417] AMF-ground may determine that it would be more efficient to transmit downlink data to another satellite (e.g., satellite 2) to which a feeder link will be connected later, rather than to satellite 1. Based on this, AMF-ground may decide not to transmit downlink data to satellite 1, to which the feeder link is currently connected. Based on this, SMF may also decide not to transmit downlink data to satellite 1.

[0418] Even in this case, if the RRC Connection Resume request transmitted by the NG-RAN of satellite 1 is based on the indication in step 5b (indication indicating that the request is based on buffered data transmission by S&F operation), AMF-onbard / AMF-ground can decide to normally transmit downlink data to satellite 1. Based on this, SMF can transmit downlink data to satellite 1.

[0419] 8) Step 8

[0420] AMF-ground may send a user plane context modification request for the UE to the SMF. The user plane context modification request may be an Nsmf_PDUSession_UpdateSMContext request.

[0421] AMF-ground can send an Nsmf_PDUSession_UpdateSMContext request to SMF. Based on this, an UP resource is created (SMF requests UPF to create a resource, and UPF creates the resource), through which uplink data can be transmitted.

[0422] The Nsmf_PDUSession_UpdateSMContext request may include information related to satellite 1. For example, the Nsmf_PDUSession_UpdateSMContext request may include the TEID and / or the IP address of satellite 1. The TEID may be information related to satellite 1.

[0423] If AMF-ground decides in step 7 not to transmit downlink data to satellite 1, the Nsmf_PDUSession_UpdateSMContext request sent to SMF may include an indication not to transmit downlink data.

[0424] At this time, AMF-ground may include information regarding the time required to establish a feeder link with a satellite suitable for downlink data transmission to the terminal in the Nsmf_PDUSession_UpdateSMContext request. Based on this, SMF may attempt to transmit downlink data to AMF-ground after the above time has elapsed.

[0425] 9) Step 9

[0426] The SMF can send an N4 Modification Request to the UPF. The N4 Modification Request may include N4 rules for uplink data. Based on this, the UPF can then receive uplink data through step 13.

[0427] Downlink data will be described later.

[0428] If the Nsmf_PDUSession_UpdateSMContext request includes an indication not to transmit downlink data, the SMF may send an N4 Modification Request to the UPF to update only the N4 rules for uplink data transmission and not update the N4 rules related to downlink data. Based on this, the UPF may not transmit downlink data.

[0429] The above N4 modification request may include an N4 rule for packet transmission (uplink data packet or downlink data packet). The N4 rule may include a Packet Detection Rule (PDR) and a Forwarding Action Rule (FAR) for each PDR. A PDR is information indicating a specific packet (e.g., uplink, downlink, etc.), and a FAR may be information indicating a processing method for the PDR (e.g., drop, buffer, forward to gNB, forward to another UPF, etc.).

[0430] For example, the N4 rule of the above N4 modification request may include multiple PDRs. Each PDR may refer to a specific packet. The N4 rule of the above N4 modification request may include a FAR corresponding to each of the multiple PDRs.

[0431] For example, if the Nsmf_PDUSession_UpdateSMContext request does not include an indication to not transmit downlink data, the N4 rule of the N4 modification request may include information to 'forward to base station (satellite 1)' for the specific downlink packet. In this case, based on this, the UPF may update the N4 rule for the specific downlink packet to 'forward to base station (satellite 1)'. In this case, the UPF may forward the specific downlink packet to satellite 1.

[0432] For example, if the Nsmf_PDUSession_UpdateSMContext request includes an indication not to transmit downlink data, the N4 rule of the N4 modification request may not include information about a specific downlink packet. In this case, since the N4 rule of the N4 modification request does not include an N4 rule for the specific downlink packet, the UPF may not update the N4 rule for the specific downlink packet. Since the N4 rule for the specific downlink packet is previously set to buffer, the UPF may buffer the specific downlink packet without forwarding it to satellite 1.

[0433] The above N4 modification request may include the TEID and / or IP address of satellite 1 received in step 8.

[0434] 10) Step 10

[0435] SMF can send Nsmf_PDUSession_UpdateSMContext response to AMF-ground. The N2 SM information included in this message can include the TEID of the UPF for uplink data transmission.

[0436] 11) Step 11

[0437] AMF-ground can pass information from BearerNsmf_PDUSession_UpdateSMContext response received from SMF through internal interface to AMF-onboard of satellite 1.

[0438] 12) Step 12

[0439] The AMF-onboard of satellite 1 may notify the NG-RAN of satellite 1 that the QoS flow associated with the UE context has been resumed via an NG-AP message (e.g., UE Context Resume Response). The NG-AP message may include the N2 SM information received by the AMF in step 10.

[0440] Through this, N3 UP resources can be created.

[0441] 13) Step 13

[0442] Based on the UE context-related QoS flow information stored by the NG-RAN of satellite 1 and the generated N3 interface, the NG-RAN of satellite 1 can transmit uplink data to the UPF.

[0443] If the UPF receives an indication in step 9 indicating not to transmit downlink data, the UPF may not transmit downlink data to satellite 1 even if there is downlink data buffered.

[0444] While the feeder link is connected to Satellite 1, even if the UPF receives additional downlink data for the terminal, the UPF may not forward the downlink data.

[0445] 14) Step 14

[0446] AMF-ground can predict that the feeder link with satellite 1 will be lost based on the satellite's orbital information and notify AMF-onboard of this.

[0447] 15a) step 15a

[0448] AMF-onboard can notify NG-RAN that the feeder link will be disconnected via NG-AP message (e.g., new IE in AMF Configuration Update or new NG-AP message).

[0449] 15b) step 11b

[0450] Satellite 1's NG-RAN can anticipate a feeder link disconnection based on the message in step 15a (or satellite orbit information stored in the NG-RAN). Based on this, Satellite 1's NG-RAN can trigger a Connection Inactive / Suspend procedure to free up terminal resources.

[0451] 16-20) Step 16 - Step 20

[0452] AMF-onboard can notify AMF-ground via its internal interface that a connection is inactive / suspended. Based on this, AMF-ground can send an Nsmf_PDUSession_UpdateSMContext request to SMF. The Nsmf_PDUSession_UpdateSMContext request can include information about the time until a suitable satellite and feeder link are connected for downlink data transmission to the terminal. Based on this, SMF can attempt to transmit downlink data to AMF-ground after this time has elapsed and update UPF about the time required for data buffering.

[0453] 21) Step 21

[0454] AMF-onboard can forward NG-AP messages received through the internal interface with AMF-ground to NG-RAN. The NG-AP messages can include a UE Context Inactive / Suspend Response. The UE Context Inactive / Suspend Response can include information indicating that the UE context-related QoS flow has been inactive / suspended.

[0455] As the satellite moves, a feeder link can be established between Satellite 2 and the ground network.

[0456] AMF-onboard of Satellite 2 can notify the eNB of Satellite 2 that the feeder link is connected.

[0457] 22) Step 22a - Step 22b

[0458] SMF can receive the time information for satellite 2 to connect through steps 3b, 8, and 17 (or other methods). Based on this, SMF can send a Namf_MT_EnableUE Reachability request to AMF-ground. AMF-ground can then send an ACK to the S-GW.

[0459] 23) Step 23

[0460] AMF-ground can decide whether to transmit the downlink data of step 1 to satellite 2.

[0461] The above decision may be made based on the last known location information of the terminal, mobility information of the terminal (e.g., whether it is a stationary terminal), orbital information of the satellite, coverage information, feeder link availability information, etc.

[0462] AMF-ground may determine that it is efficient to transmit the downlink data to satellite 2. Based on this, AMF-ground may decide to transmit the downlink data of step 1 to satellite 2.

[0463] 24) Step 24

[0464] Satellite 2's AMF-ground can notify AMF-onboard via its internal interface that it needs to generate UP for downlink data transmission.

[0465] 25) Step 25

[0466] The NG-RAN of Satellite 2 can request AMF-onboard to resume UE context related QoS flows via an NG-AP message (e.g., UE Context Resume Request).

[0467] 26) Step 26

[0468] AMF-onboard of Satellite 2 can notify AMF-ground to resume the UE context and QoS flow through its internal interface.

[0469] 27) Step 27

[0470] AMF-groud may send a user plane context modification request for the UE to the SMF. The user plane context modification request may be an Nsmf_PDUSession_UpdateSMContext request.

[0471] AMF-ground can send an Nsmf_PDUSession_UpdateSMContext request to SMF, based on which an UP resource can be created.

[0472] The Nsmf_PDUSession_UpdateSMContext request may include information related to Satellite 2. For example, the Nsmf_PDUSession_UpdateSMContext request may include the TEID and / or the IP address of Satellite 2. The TEID may be information related to Satellite 2.

[0473] Based on the decision in step 23, the Nsmf_PDUSession_UpdateSMContext request may not include an indication not to send downlink data.

[0474] Alternatively, the AMF may provide an indication / information to the SMF to initiate (resume) transmission of downlink data.

[0475] 28) Step 28

[0476] The SMF can verify that there is no indication to not send downlink data and send an N4 Modification Request to the UPF to update the N4 rules so that UL / DL transmission to the terminal can proceed normally.

[0477] The above N4 modification request may include the TEID and / or IP address of Satellite 2 received in step 27.

[0478] 29) Step 29

[0479] SMF may send an Nsmf_PDUSession_UpdateSMContext response to AMF-ground in response to the request in step 27.

[0480] The N2 SM information included in the Nsmf_PDUSession_UpdateSMContext response may include the TEID (Tunnel Endpoint Identifier) ​​of the UPF for uplink data transmission.

[0481] 30) Step 30

[0482] AMF-ground can pass information from the Nsmf_PDUSession_UpdateSMContext response received from SMF through the internal interface to AMf-onboard of satellite 2.

[0483] 31) Step 31

[0484] The AMF-onboard of Satellite 2 may transmit information to the NG-RAN via an NG-AP message that the UE context-related QoS flow has been resumed. The NG-AP message may include the N2 SM information received in step 29.

[0485] 32) Step 32

[0486] UPF can forward buffered downlink data to NG-RAN of satellite 2 through N3 tunnel.

[0487] While the feeder link is connected to Satellite 2, if the UPF receives additional downlink data for the terminal, the UPF can forward the downlink data to the NG-RAN of Satellite 2.

[0488] 33) Step 3

[0489] Satellite 2's NG-RAN can transmit uplink data from the terminal to the UPF through the created N3 tunnel.

[0490] When using CP CIoT in 5GS, AMF-ground can transmit uplink data including User Data in the Nsmf_PDUSession_SendMOData service operation due to uplink data.

[0491] If AMF-ground determines that the satellite currently connected to the feeder link is not a suitable satellite for transmitting downlink data based on the satellite's orbital information, etc., AMF-ground may transmit the Nsmf_PDUSession_SendMOData service operation with an indication not to transmit downlink data.

[0492] An SMF that receives the indication may not forward downlink data to AMF-ground.

[0493] AMF-ground can transmit information about the time required for a suitable satellite and feeder link to be connected for downlink data transmission to the terminal within the Nsmf_PDUSession_SendMOData service operation. Upon receiving this, the SMF can attempt to transmit downlink data to AMF-ground after the specified time has elapsed.

[0494] After this, SMF can send Namf_MT_EnableUEReachability Request or Namf_Communication_N1N2MessageTransfer to AMF-ground for downlink data transmission as per clause 4.24.2 of TS 23.502 v18.7.0. If there is currently a satellite and feeder link connected suitable for downlink data transmission, AMF-ground can send a reachable response to SMF. SMF can update the N4 rule of UPF through N4 Session Modification Request to ensure normal transmission of downlink data.

[0495] Alternatively, after this, if AMF-ground determines (decides) that the satellite currently connected to the feeder link is a suitable satellite for transmitting downlink data based on the satellite's orbital information, etc., AMF-ground may not include an indication not to transmit downlink data when transmitting uplink data by including user data in the Nsmf_PDUSession_SendMOData service operation due to uplink data.

[0496] Alternatively, after this, if AMF-ground determines (decides) that the satellite currently connected to the feeder link is a suitable satellite for transmitting downlink data based on the satellite's orbital information, etc., AMF-ground may provide an indication / information notifying SMF to perform (continue) downlink data transmission.

[0497] Then, SMF can pass downlink data to AMF via Namf_Communication_N1N2MessageTransfer.

[0498] II. Second Example

[0499] In EPS, a method can be proposed that uses a TEID value preset in the network.

[0500] In the second embodiment, except for the operations described below, the operations described in FIGS. 11, 12 and 13 of the first embodiment can be performed.

[0501] According to the first embodiment, the MME-ground can send a separate indication to the S-GW, as in Step 6a of FIG. 13.

[0502] Unlike the first embodiment, the network can configure a specific TEID value not to be used for data transmission. The specific TEID value can be set to a value not used when creating a general S1-U bearer.

[0503] Typically, the MME receives a TEID value from the eNB. The MME includes the received TEID value in the S1-U eNodeB F-TEID for downlink data of the S-GW in a Modify Bearer Request and forwards it to the S-GW. The S-GW sends downlink data for the S1-U bearer created based on the TEID value.

[0504] In the second embodiment, the MME-ground receives a TEID value from the eNB. The MME-ground includes a specific TEID value (a TEID that the network has set not to use for data transmission) in the S1-U eNodeB F-TEID for downlink data of the S-GW in a Modify Bearer Request, instead of the received TEID value, and transmits the S-GW. The S-GW can decide not to send downlink data for the S1-U bearer created based on the TEID value. The specific TEID value can be set to a value that is not used when creating a general S1-U bearer.

[0505] When CP CIoT EPS Optimization is used, the MME-ground may send the S11-U MME F-TEID field in the Modify Bearer Request to the S-GW with a specific TEID value (a TEID that the network has not configured to be used for data transmission). The S-GW may decide not to send downlink data for the S11-U bearer created with the corresponding TEID. The specific TEID value may be set to a value that is not used when creating a general S1-U bearer.

[0506] Thereafter, in step 18a of FIG. 13 of the first embodiment, the MME-ground can include the TEID value received from the eNB as the S1-U eNodeB F-TEID for the downlink data of the S-GW in a Modify Bearer Request and transmit it to the S-GW. Then, the downlink data can be transmitted normally.

[0507] In a network with a split MME (5GS: split AMF) structure that supports S&F operation, even if a feeder link of a satellite is connected and UP resources for uplink data transmission are created, the MME (5GS: AMF)-ground can determine whether to transmit downlink to the satellite. Based on this, the MME (5GS: AMF)-ground can notify the S-GW (5GS: SMF) not to transmit the downlink data. Then, the downlink data can be transmitted to the terminal with less delay through the satellite that can transmit the downlink faster.

[0508] In this specification, a method for efficiently transmitting downlink data for a terminal in a split MME (split AMF) structure supporting S&F operation can be proposed.

[0509] When a satellite and feeder link are connected and UP resources are created for the satellite, the MME can determine, based on satellite orbital information, that the satellite is suitable for transmitting downlink data to the terminal. Based on this, the MME can decide to create UP resources between the eNB and the S-GW to transmit and receive data, as in the existing operation.

[0510] When a satellite and feeder link are connected and UP resources are created for the satellite, the MME may determine, based on satellite orbit information, that the satellite is not suitable for transmitting downlink data to the terminal. In this case, the MME may decide not to create UP resources between the eNB and the S-GW. However, even in this case, if UP resources are created between the eNB and the S-GW due to uplink data transmission from the terminal, the S-GW will transmit downlink data to the satellite's eNB through the UP path created according to conventional operation. Therefore, the following method can be applied to prevent this.

[0511] With regard to how to transmit separate indications, the following actions can be performed in EPS:

[0512] - When the MME-ground creates UP resources between the eNB and the S-GW due to uplink data transmission, the MME-ground may transmit a modification bearer request including an indication not to transmit downlink data. Then, even if the MME-ground informs the eNB of downlink resource information through the modification bearer request, the S-GW may decide not to transmit downlink data based on the indication. In addition to the modification bearer request, the MME-ground may transmit information on the time until a satellite and a feeder link suitable for downlink data transmission to the UE are connected. The time information may be included in a message transmitted when the connection with the satellite connected to the feeder link is released. The S-GW that receives this may attempt to transmit downlink data to the MME-ground after the specified time has elapsed.

[0513] - Afterwards, when a satellite and feeder link suitable for downlink data transmission are connected and downlink data is generated or uplink data requires the creation of UP resources, the MME-ground can create UP resources by transmitting a Modify Bearer Request that does not include the aforementioned indication so that downlink data can be transmitted normally as in the conventional operation. Then, the S-GW can transmit the downlink data to the connected satellite. Alternatively, the MME may provide an indication / information notifying the S-GW to perform / continue downlink data transmission.

[0514] - When CP CIoT EPS Optimization is used, if MME-ground receives a UP resource creation request from eNB through MME-onboard or a downlink data notification (DL Data Notification) from S-GW and S11-U UP resource creation between MME and S-GW is required, MME-ground may determine that the satellite currently connected to the feeder link is not a suitable satellite for transmitting the downlink based on the satellite's orbit information, etc. Then, MME-ground may transmit an indication indicating not to transmit downlink data (additionally, time information until a feeder link is connected to a satellite suitable for downlink data transmission) in the modified bearer request. In this way, it can operate similarly to general UP operation and UP CIoT EPS Optimization.

[0515] With regard to how to transmit separate indications, the following actions can be performed in 5GS:

[0516] - When a satellite and a feeder link are connected, downlink data is generated, or a request for UP resource creation by the gNB is received, when AMF-ground creates SMF and UP resources, AMF-ground can determine whether the satellite currently connected to the feeder link is a suitable satellite for transmitting downlink data through satellite orbit information, etc. Based on this, AMF-ground can decide whether to create UP resources for the downlink. If it is determined that the satellite is not a suitable satellite for transmitting downlink data, AMF-ground can transmit to SMF an Nsmf_PDUSession_UpdateSMContext request message for creating UP resources between the gNB and the UPF due to uplink data transmission, including an indication not to send downlink data. AMF-ground can additionally transmit the Nsmf_PDUSession_UpdateSMContext request message including the time information until a satellite suitable for downlink data transmission and a feeder link are connected. The time information may also be included in a message transmitted when the connection with the satellite connected to the feeder link is released. An SMF that receives this indication may attempt to transmit downlink data to AMF-ground after the specified time has elapsed. An SMF that receives the above-mentioned indication may not update the N4 rules related to downlink data in the N4 Modification Request to the UPF. In this case, the UPF may not transmit the downlink data.

[0517] - When a satellite and feeder link to transmit (forward) downlink data are connected thereafter, and downlink data is generated or UP resource creation is required by uplink data, AMF-ground may not include the indication (indication not to transmit downlink data) as in the conventional operation when transmitting an Nsmf_PDUSession_UpdateSMContext request message to SMF (or AMF may provide indication / information notifying SMF to perform / continue downlink data transmission). Then, SMF may update the N4 rule for UL / DL data transmission to UPF so that both UL / DL data can be transmitted.

[0518] With regard to how to transmit separate indications, the following actions can be taken when CP CIoT is used in 5GS:

[0519] - When transmitting uplink data including user data in the Nsmf_PDUSession_SendMOData service operation in AMF-ground due to uplink data, an indication may be included to not transmit downlink data. The SMF may not forward the downlink data to AMF-ground according to the indication. The AMF-ground may transmit to the SMF the Nsmf_PDUSession_SendMOData service message including the time until a suitable satellite and feeder link for transmitting downlink data to the UE are connected. The SMF that receives this may attempt to transmit downlink data to AMF-ground after the time has elapsed.

[0520] - After this, SMF can send Namf_MT_EnableUEReachability request or Namf_Communication_N1N2MessageTransfer to AMF-ground for downlink data transmission as per clause 4.24.2 of TS 23.502 v18.7.0. AMF-ground can send a reachable response if it is currently connected to a satellite and feeder link suitable for downlink data transmission. Then, downlink data can be transmitted normally.

[0521] - Or, after this, when AMF-ground transmits uplink data including user data in Nsmf_PDUSession_SendMOData service operation due to uplink data, AMF-ground may determine that the satellite currently connected to the feeder link is a suitable satellite for transmitting downlink data based on the satellite's orbital information, etc. Then, AMF-ground may not include an indication not to transmit downlink data (or AMF may provide an indication / information notifying SMF to perform / continue downlink data transmission). Then, SMF may transmit downlink data to AMF through Namf_Communication_N1N2MessageTransfer.

[0522] Regarding how to use preset TEID values ​​in the network, the following actions can be performed:

[0523] - A specific TEID value that is not to be forwarded in the network can be preset. Instead of sending a separate indication (indication not to transmit downlink data), the MME-ground can include the specific TEID value in the S1-U eNodeB F-TEID value (in case of using UP or UP CIoT) or the S11-U MME F-TEID value (in case of using CP CIoT) in the Modify Bearer Request and forward it to the S-GW. The S-GW can decide not to send DL data for the S1-U (or S11-U) bearer created with the specific TEID. For this purpose, the specific preset TEID value can be set to a value that is not used when creating a general S1-U (or S11-U) bearer.

[0524] 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.

[0525] Figure 18 illustrates the procedure of the first NF for the disclosure of this specification.

[0526] 1. A first NF (Network Function) can receive notification of downlink data for a UE (User Equipment) from a second NF.

[0527] The above first NF serves the UE and manages the mobility of the UE,

[0528] 2. Based on the connection between the first satellite and the feeder link, the first NF can determine whether to transmit the downlink data to the first satellite.

[0529] The step of determining whether to transmit the downlink data to the first satellite may be performed based on at least one of: location information of the UE, mobility information of the UE, orbital information of the first satellite, coverage information of the first satellite, orbital information of the second satellite, and coverage information of the second satellite.

[0530] 3. The first NF may transmit a first modification request message for a user plane context for the UE to the second NF.

[0531] The above first modification request message may include information related to the first satellite.

[0532] Based on the decision not to transmit the downlink data to the first satellite, the first modification request message may include an indication not to transmit the downlink data to the first satellite.

[0533] The step of determining whether to transmit the downlink data to the first satellite is:

[0534] The first NF may include a step of determining that the downlink data will be transmitted to the second satellite with less delay than the downlink data will be transmitted to the first satellite.

[0535] The above first modification request message may include information about when the second satellite is connected to the feeder link.

[0536] Based on the connection of the second satellite and the feeder link, the first NF can determine whether to transmit the downlink data to the second satellite.

[0537] The step of determining whether to transmit the downlink data to the second satellite may be performed based on at least one of: location information of the UE, mobility information of the UE, orbital information of the second satellite, and coverage information of the second satellite.

[0538] The first NF may send a second modification request message for a user plane context for the UE to the second NF.

[0539] The second modification request message may include information related to the second satellite.

[0540] Based on the decision to transmit the downlink data to the second satellite, the second modification request message may not include an indication not to transmit the downlink data to the second satellite.

[0541] Based on the connection of the second satellite and the feeder link, the first NF can determine whether to transmit the downlink data to the second satellite.

[0542] The step of determining whether to transmit the downlink data to the second satellite may be performed based on at least one of: location information of the UE, mobility information of the UE, orbital information of the second satellite, and coverage information of the second satellite.

[0543] The first NF may send a second modification request message for a user plane context for the UE to the second NF.

[0544] The second modification request message may include information related to the second satellite.

[0545] Based on the decision to transmit the downlink data to the second satellite, the second modification request message may include information to transmit the downlink data.

[0546] The above first NF may be MME (Mobility Management Entity)-ground.

[0547] The above second NF may be an S-GW (Serving Gateway).

[0548] The above first NF may be AMF (Access & Mobility Management Function)-ground.

[0549] The above second NF may be a Session Management Function (SMF).

[0550] The information related to the first satellite may include a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

[0551] 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.

[0552] Figure 19 illustrates the S-GW procedure for the disclosure of this specification.

[0553] 1. The S-GW (Serving Gateway) can receive downlink data for the UE (User Equipment) from the PDN GW (Packet data Networks Gateway).

[0554] 2. The above S-GW can send a notification of the above downlink data to the MME (Mobility Management Entity)-ground.

[0555] The above MME-ground can serve the UE and manage the mobility of the UE.

[0556] 3. Based on the connection of the first satellite and the feeder link, the S-GW can receive a first bearer modification request message from the MME-ground.

[0557] The above first bearer modification request message may include information related to the first satellite.

[0558] 4. Based on the information related to the first satellite, the S-GW can transmit the downlink data to the first satellite.

[0559] Based on the fact that the first bearer modification request message includes an indication not to transmit the downlink data to the first satellite, the S-GW may skip transmitting the downlink data.

[0560] The above first bearer modification request message may include information about when the second satellite is connected to the feeder link.

[0561] Based on the connection of the second satellite and the feeder link, the S-GW can receive a second bearer modification request message from the MME-ground.

[0562] The above second bearer modification request message may include information related to the second satellite.

[0563] The above S-GW may send a response message to the second bearer modification request message to the above MME-ground.

[0564] Based on the fact that the second bearer modification request message does not include an indication not to transmit the downlink data to the second satellite, the response message may include a TEID (Tunnel Endpoint Identifier).

[0565] The S-GW may transmit the downlink data to the second satellite based on the information related to the second satellite and the second bearer modification request message does not include an indication not to transmit the downlink data to the second satellite.

[0566] Based on the connection of the second satellite and the feeder link, the S-GW can receive a second bearer modification request message from the MME-ground.

[0567] The above second bearer modification request message may include information related to the second satellite.

[0568] The above S-GW may send a response message to the second bearer modification request message to the above MME-ground.

[0569] Based on the fact that the second bearer modification request message includes information to transmit the downlink data, the response message may include a TEID (Tunnel Endpoint Identifier).

[0570] Based on the fact that the second bearer modification request message includes information to transmit the downlink data, the S-GW can transmit the downlink data to the second satellite.

[0571] The information related to the first satellite may include a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

[0572] 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.

[0573] Figure 20 illustrates the SMF procedure for the disclosure of this specification.

[0574] 1. Based on the connection between the first satellite and the feeder link, the SMF (Session Management Function) can receive a first update request message for the SM context for the PDU session from the AMF (Access and Mobility management Function)-ground.

[0575] The above AMF-ground can serve UE (User Equipment).

[0576] The above first update request message may include information related to the first satellite.

[0577] The first update request message may include an indication to the first satellite not to transmit downlink data for the UE.

[0578] 2. Based on the first update request message, the SMF can transmit a first N4 modification request message to the UPF (User Plane Function).

[0579] Based on the above first update request message including an indication not to transmit downlink data for the UE to the first satellite, the first N4 modification request message may include an indication not to update N4 rules related to downlink data for the UE.

[0580] Based on the connection of the second satellite and the feeder link, the SMF can receive a second update request message for the SM context for the PDU session from the AMF-ground.

[0581] The second update request message may include information related to the second satellite.

[0582] Based on the second update request message, the SMF can transmit a first N4 modification request message to the UPF.

[0583] Based on the fact that the second update request message does not include an indication to the second satellite not to transmit downlink data for the UE, the second N4 modification request message may include an indication to update the N4 rules related to downlink data for the UE.

[0584] Based on the connection of the second satellite and the feeder link, the SMF can receive a second update request message for the SM context for the PDU session from the AMF-ground.

[0585] The second update request message may include information related to the second satellite.

[0586] Based on the second update request message, the SMF can transmit a first N4 modification request message to the UPF.

[0587] Based on the second update request message including information to cause the second satellite to transmit downlink data for the UE, the second N4 modification request message may include an indication to update N4 rules related to downlink data for the UE.

[0588] The information related to the first satellite may include a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

[0589] Hereinafter, a device for performing communication according to some embodiments of the present specification will be described.

[0590] For example, a device may include a processor, a transceiver, and memory.

[0591] For example, a processor may be configured to be operatively coupled with memory and a processor.

[0592] The operations performed by the processor include: a step in which a first NF (Network Function) receives a notification of downlink data for a UE (User Equipment) from a second NF; a step in which the first NF serves the UE and manages mobility of the UE, and a step in which the first NF determines whether to transmit the downlink data to the first satellite based on a feeder link being connected to the first satellite; The step of determining whether to transmit the downlink data to the first satellite is performed based on at least one of location information of the UE, mobility information of the UE, orbital information of the first satellite, coverage information of the first satellite, orbital information of the second satellite, and coverage information of the second satellite, and includes a step in which the first NF transmits to the second NF a first modification request message for a user plane context for the UE, the first modification request message including information related to the first satellite, and based on a decision not to transmit the downlink data to the first satellite, the first modification request message may include an indication not to transmit the downlink data to the first satellite.

[0593] Below, a processor of a device for providing communication according to some embodiments of the present specification is described.

[0594] The operations performed by the processor include: a step in which a first NF (Network Function) receives a notification of downlink data for a UE (User Equipment) from a second NF; a step in which the first NF serves the UE and manages mobility of the UE, and a step in which the first NF determines whether to transmit the downlink data to the first satellite based on a feeder link being connected to the first satellite; The step of determining whether to transmit the downlink data to the first satellite is performed based on at least one of location information of the UE, mobility information of the UE, orbital information of the first satellite, coverage information of the first satellite, orbital information of the second satellite, and coverage information of the second satellite, and includes a step in which the first NF transmits to the second NF a first modification request message for a user plane context for the UE, the first modification request message including information related to the first satellite, and based on a decision not to transmit the downlink data to the first satellite, the first modification request message may include an indication not to transmit the downlink data to the first satellite.

[0595] Hereinafter, a non-volatile computer-readable medium storing one or more commands for providing mobile communication according to some embodiments of the present specification is described.

[0596] According to some embodiments of the present disclosure, the technical features of the present disclosure may be implemented directly in hardware, software executed by a processor, or a combination of the two. For example, a method performed by a wireless device in wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or other storage media.

[0597] Some examples of storage media are coupled to the processor, allowing the processor to read information from the storage media. Alternatively, the storage media may be integrated into the processor. The processor and storage media may reside in an ASIC. In other examples, the processor and storage media may reside as separate components.

[0598] Computer-readable media may include tangible and non-volatile computer-readable storage media.

[0599] For example, nonvolatile computer-readable media may include random access memory (RAM), such as synchronized dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), read-only memory (EEPROM), flash memory, magnetic or optical data storage media, or any other media that can be used to store instructions or data structures. Nonvolatile computer-readable media may also include combinations of the above.

[0600] Additionally, the methods described herein can be realized at least in part by a computer-readable communication medium that carries or transmits code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0601] According to some embodiments of the present disclosure, a non-transitory computer-readable medium has one or more instructions stored thereon. The one or more stored instructions can be executed by a processor of a base station.

[0602] One or more stored commands comprise: a step in which a first NF (Network Function) receives notification of downlink data for a UE (User Equipment) from a second NF; the first NF serves the UE and manages mobility of the UE, and the first NF determines whether to transmit the downlink data to the first satellite based on a feeder link being connected to the first satellite; The step of determining whether to transmit the downlink data to the first satellite is performed based on at least one of location information of the UE, mobility information of the UE, orbital information of the first satellite, coverage information of the first satellite, orbital information of the second satellite, and coverage information of the second satellite, and includes a step in which the first NF transmits to the second NF a first modification request message for a user plane context for the UE, the first modification request message including information related to the first satellite, and based on a decision not to transmit the downlink data to the first satellite, the first modification request message may include an indication not to transmit the downlink data to the first satellite.

[0603] This specification may have various effects.

[0604] For example, according to the disclosure of the present specification, a satellite suitable for downlink data transmission can be selected to minimize the delay of downlink data.

[0605] The effects that can be achieved through 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.

[0606] 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. As a method, A step in which a first NF (Network Function) receives notification of downlink data for a UE (User Equipment) from a second NF; The above first NF serves the UE and manages the mobility of the UE, A step in which the first NF determines whether to transmit the downlink data to the first satellite based on the connection between the first satellite and the feeder link; The step of determining whether to transmit the downlink data to the first satellite is performed based on at least one of the location information of the UE, mobility information of the UE, orbital information of the first satellite, coverage information of the first satellite, orbital information of the second satellite, and coverage information of the second satellite. The first NF comprises a step of transmitting a first modification request message for a user plane context for the UE to the second NF, The above first modification request message includes information related to the first satellite, A method wherein the first modification request message includes an indication not to transmit the downlink data to the first satellite based on a decision not to transmit the downlink data to the first satellite.

2. In paragraph 1, The step of determining whether to transmit the downlink data to the first satellite is: A step in which the first NF determines that the downlink data will be transmitted to the second satellite with less delay than when transmitted to the first satellite, A method wherein the first modification request message includes information about when the second satellite is connected to the feeder link.

3. In paragraph 1 or 2, A step in which the first NF determines whether to transmit the downlink data to the second satellite based on the connection of the second satellite and the feeder link; The step of determining whether to transmit the downlink data to the second satellite is performed based on at least one of the location information of the UE, mobility information of the UE, orbital information of the second satellite, and coverage information of the second satellite. The first NF comprises a step of transmitting a second modification request message for a user plane context for the UE to the second NF, The second modification request message includes information related to the second satellite, A method wherein the second modification request message does not include an indication not to transmit the downlink data to the second satellite based on the decision to transmit the downlink data to the second satellite.

4. In paragraph 1 or 2, A step in which the first NF determines whether to transmit the downlink data to the second satellite based on the connection of the second satellite and the feeder link; The step of determining whether to transmit the downlink data to the second satellite is performed based on at least one of the location information of the UE, mobility information of the UE, orbital information of the second satellite, and coverage information of the second satellite. The first NF comprises a step of transmitting a second modification request message for a user plane context for the UE to the second NF, The second modification request message includes information related to the second satellite, A method wherein the second modification request message includes information to transmit the downlink data based on a decision to transmit the downlink data to the second satellite.

5. In any one of paragraphs 1 to 4, The above first NF is MME (Mobility Management Entity)-ground, The above second NF is a S-GW (Serving Gateway).

6. In any one of paragraphs 1 to 4, The above first NF is AMF (Access & Mobility Management Function)-ground, The above second NF is a method of SMF (Session Management Function).

7. In any one of paragraphs 1 to 5, A method in which the information related to the first satellite includes a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

8. As a method, A step in which an S-GW (Serving Gateway) receives downlink data for a UE (User Equipment) from a PDN GW (Packet data Networks Gateway); A step in which the S-GW transmits a notification of the downlink data to the MME (Mobility Management Entity)-ground; The above MME-ground serves the UE and manages the mobility of the UE, A step in which the S-GW receives a first bearer modification request message from the MME-ground based on the connection of the first satellite and the feeder link; The above first bearer modification request message includes information related to the first satellite, A step in which the S-GW transmits the downlink data to the first satellite based on information related to the first satellite; A method in which the S-GW skips transmitting the downlink data based on the first bearer modification request message including an indication not to transmit the downlink data to the first satellite.

9. In paragraph 8, A method wherein the first bearer modification request message includes information about when the second satellite is connected to the feeder link.

10. In paragraph 8 or 9, A step in which the S-GW receives a second bearer modification request message from the MME-ground based on the connection of the second satellite and the feeder link; The above second bearer modification request message includes information related to the second satellite, A step in which the S-GW transmits a response message to the second bearer modification request message to the MME-ground; Based on the fact that the second bearer modification request message does not include an indication not to transmit the downlink data to the second satellite, the response message includes a TEID (Tunnel Endpoint Identifier), A method further comprising: the S-GW transmitting the downlink data to the second satellite based on information related to the second satellite, wherein the second bearer modification request message does not include an indication not to transmit the downlink data to the second satellite.

11. In paragraph 8 or 9, A step in which the S-GW receives a second modification request message for a user plane context for the UE from the MME-ground based on the connection of the second satellite and the feeder link; The above second bearer modification request message includes information related to the second satellite, A step in which the S-GW transmits a response message to the second bearer modification request message to the MME-ground; Based on the above second bearer modification request message including information to transmit the downlink data, the response message includes a TEID (Tunnel Endpoint Identifier), A method further comprising a step of the S-GW transmitting the downlink data to the second satellite based on the information related to the second satellite and the information including the second bearer modification request message to transmit the downlink data.

12. In any one of the clauses 8 to 11, A method in which the information related to the first satellite includes a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

13. Based on the connection of the first satellite and the feeder link, the SMF (Session Management Function) receives a first update request message for the SM context for the PDU session from the AMF (Access and Mobility management Function)-ground; The above AMF-ground serves UE (User Equipment), The above first update request message includes information related to the first satellite, The first update request message includes an indication not to transmit downlink data for the UE to the first satellite, A method comprising the step of: based on the first update request message, the SMF transmitting a first N4 modification request message to a User Plane Function (UPF).

14. In paragraph 13, A method wherein the first N4 modification request message does not include an N4 rule related to downlink data for the UE, based on the first update request message including an indication not to transmit downlink data for the UE to the first satellite.

15. In paragraph 13 or 14, Based on the connection of the second satellite and the feeder link, the SMF receives a second update request message for the SM context for the PDU session from the AMF-ground; The second update request message includes information related to the second satellite, A method further comprising the step of: based on the second update request message, the SMF transmitting a first N4 modification request message to the UPF. A method wherein the second N4 modification request message includes an N4 rule related to downlink data for the UE, based on the second update request message not including an indication not to transmit downlink data for the UE to the second satellite.

16. In paragraph 13 or 14, Based on the connection of the second satellite and the feeder link, the SMF receives a second update request message for the SM context for the PDU session from the AMF-ground; The second update request message includes information related to the second satellite, A method further comprising the step of: based on the second update request message, the SMF transmitting a first N4 modification request message to the UPF. A method wherein the second N4 modification request message includes an N4 rule related to downlink data for the UE, based on the second update request message including information for causing the second satellite to transmit downlink data for the UE.

17. In any one of the clauses 13 to 16, A method in which the information related to the first satellite includes a TEID (Tunnel Endpoint Identifier) ​​and an IP address related to the first satellite.

18. As the first NF (Network Function), At least one transmitter and receiver; Contains at least one processor, The operation performed by the above processor is an AMF method according to any one of claims 1 to 7.

19. As a S-GW (Serving Gateway) that performs communication, At least one transmitter and receiver; Contains at least one processor, The operation performed by the above processor is an S-GW method according to any one of claims 8 to 12.

20. As a SMF (Session Management Function) that performs communication, At least one transmitter and receiver; Contains at least one processor, The operation performed by the above processor is an SMF method according to any one of claims 13 to 17.

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