Method for performing store-and-forward

Abstract

An embodiment of the present disclosure provides a method for performing communication by a first satellite. The method comprises the steps of: receiving, from an AMF, information indicating that a UE supports S&F, and storing the information in a UE context; receiving data from the UE and storing same; and maintaining the UE context.

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] The question arises as to how S&F operations are performed when the satellite serving the terminal changes.

[0006] The satellite maintains the UE context and transmits MO data when it later connects to the ground station.

[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] Figures 6 and 7 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0013] Figure 8 shows an example of basic satellite operation.

[0014] Figure 9 shows an example of S&F satellite operation.

[0015] Figure 10 shows an example of a process of transitioning from an RRC inactive state to an RRC connected state.

[0016] Figure 11 shows an example of the situation at time T1.

[0017] Figure 12 shows an example of the situation at time T2.

[0018] Figure 13 shows an example of the situation at time T3.

[0019] Figure 14 shows an example of an Xn setting procedure according to an embodiment of the present specification.

[0020] Figure 15 shows an example of an NG setting procedure according to an embodiment of the present specification.

[0021] Figure 16 illustrates an example of a registration procedure according to an embodiment of the present specification.

[0022] Figures 17 and 18 illustrate examples of S&F procedures according to embodiments of the present specification.

[0023] Figure 19 illustrates the procedure of the first satellite for the disclosure of this specification.

[0024] Figure 20 illustrates the AMF's procedure for disclosure of this specification.

[0025] Figure 21 illustrates the UE's procedure for disclosure of this specification.

[0026] 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).

[0027] 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.

[0028] 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.

[0029] 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."

[0030] 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."

[0031] 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.”

[0032] 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”.

[0033] 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."

[0034] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0035] 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).

[0036] 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.

[0037] Figure 1 illustrates an example of a communication system to which the implementation of this specification is applied.

[0038] 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.

[0039] 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).

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] For example, a UAV may be an aircraft that is unmanned and navigated by radio control signals.

[0045] 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.

[0046] For example, a public safety device may include an image relay device or imaging device that can be worn on the user's body.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] For example, a weather / environment device may include a device that monitors or predicts the weather / environment.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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).

[0060] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0061] 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).

[0062] Frequency Range DefinitionFrequency RangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0063] 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.

[0064] Figure 2 illustrates an example of a wireless device to which the implementation of the present specification is applied.

[0065] 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.

[0066] 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).

[0067] 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).

[0068] 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).

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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).

[0073] 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).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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).

[0081] 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).

[0082] 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.

[0083] 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.

[0084] In this specification, a base station may be referred to as a Node B, an eNode B (eNB), or a gNB.

[0085] Figure 3 shows an example of a UE to which the implementation of this specification is applied.

[0086] Referring to FIG. 3, the UE (100) can correspond to the first wireless device (100) of FIG. 2.

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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).

[0092] 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).

[0093] 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.

[0094] 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).

[0095] Figure 4 is a structural diagram of a next-generation mobile communications network.

[0096] 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).

[0097] 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).

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] The illustrated PCF (430) is a node that controls the business operator's policy.

[0104] The illustrated AF (450) is a server for providing various services to the UE (100).

[0105] 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).

[0106] 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.

[0107] 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.

[0108] 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.

[0109] Figure 5 shows an example of a 5G system structure to which the implementation of this specification is applied.

[0110] The 5G system (5GS; 5G system) structure consists of the following network functions (NF; Network Function).

[0111] - AUSF (Authentication Server Function)

[0112] - AMF (Access and Mobility Management Function)

[0113] - DN (Data Network), 예를 들어 운영자 서비스, 인터넷 접속 또는 타사 서비스

[0114] - USDF (Unstructured Data Storage Function)

[0115] - NEF (Network Exposure Function)

[0116] - I-NEF (Intermediate NEF)

[0117] - NRF (Network Repository Function)

[0118] - NSSF (Network Slice Selection Function)

[0119] - PCF (Policy Control Function)

[0120] - SMF (Session Management Function)

[0121] - UDM (Unified Data Management)

[0122] - UDR (Unified Data Repository)

[0123] - UPF (User Plane Function)

[0124] - UCMF (UE radio Capability Management Function)

[0125] - AF (Application Function)

[0126] - UE (User Equipment)

[0127] - (R)AN ((Radio) Access Network)

[0128] - 5G-EIR (5G-Equipment Identity Register)

[0129] - NWDAF (Network Data Analytics Function)

[0130] - CHF (CHarging Function)

[0131] Additionally, the following network features may be considered:

[0132] - N3IWF (Non-3GPP InterWorking Function)

[0133] - TNGF (Trusted Non-3GPP Gateway Function)

[0134] - W-AGF (Wireline Access Gateway Function)

[0135] 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.

[0136] For clarity of the point-to-point diagram in Figure 5, UDSF, NEF, and NRF are not illustrated. However, all network functions shown can interact with UDSF, UDR, NEF, and NRF as needed.

[0137] 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.

[0138] The 5G system architecture includes the following benchmarks:

[0139] - N1: Reference point between UE and AMF.

[0140] - N2: Reference point between (R)AN and AMF.

[0141] - N3: Reference point between (R)AN and UPF.

[0142] - N4: Reference point between SMF and UPF.

[0143] - N6: Reference point between UPF and data network.

[0144] - N9: Reference point between two UPFs.

[0145] The following benchmarks illustrate the interactions that exist between NF services in NF.

[0146] - N5: Reference point between PCF and AF.

[0147] - N7: Reference point between SMF and PCF.

[0148] - N8: Reference point between UDM and AMF.

[0149] - N10: Reference point between UDM and SMF.

[0150] - N11: Reference point between AMF and SMF.

[0151] - N12: Reference point between AMF and AUSF.

[0152] - N13: Reference point between UDM and AUSF.

[0153] - N14: Reference point between two AMFs.

[0154] - N15: Reference point between PCF and AMF for non-roaming scenarios, and reference point between PCF and AMF of visited network for roaming scenarios.

[0155] - N16: Reference point between two SMFs (in case of roaming, between the SMF of the visited network and the SMF of the home network)

[0156] - N22: Reference point between AMF and NSSF.

[0157] In some cases, two NFs may need to be interconnected to serve a UE.

[0158] <Registration Procedure>

[0159] Describes the registration procedure. See section 4.2.2.2 of 3GPP TS 23.502 V16.3.0 (2019-12).

[0160] Figures 6 and 7 illustrate examples of registration procedures to which the implementation of the present specification applies.

[0161] A UE must register with the network to receive services, enable mobility tracking, and enable reachability. The UE initiates the registration process using one of the following registration types:

[0162] - Initial registration for 5GS; or

[0163] - mobility registration update; or

[0164] - Periodic registration update; or

[0165] - Emergency registration

[0166] The general registration procedures of Figures 6 and 7 apply to all registration procedures described above, but periodic registration updates do not need to include all parameters used in other registration procedures.

[0167] The general registration procedures of Figures 6 and 7 can also be used when registering for a 3GPP connection when the UE is already registered for a non-3GPP connection, and vice versa. Registering for a 3GPP connection when the UE is already registered for a non-3GPP connection scenario may require an AMF change.

[0168] First, the procedure of Fig. 6 is described.

[0169] (1) Step 1: The UE transmits a Registration Request message to the (R)AN. The Registration Request message corresponds to an AN message.

[0170] The registration request message may include AN parameters. For NG-RAN, the AN parameters include, for example, the 5G SAE temporary mobile subscriber identity (5G-S-TMSI) or globally unique AMF ID (GUAMI), the selected public land mobile network (PLMN) ID (or PLMN ID and network identifier (NID)), and the requested network slice selection assistance information (NSSAI). The AN parameters also include an establishment cause. The establishment cause provides the reason for requesting establishment of an RRC connection. Whether and how the UE includes the requested NSSAI as part of the AN parameters depends on the value of the access stratum connection establishment NSSAI inclusion mode parameter.

[0171] A registration request message may include a registration type. The registration type indicates whether the UE wants to perform an initial registration (i.e., the UE is in RM-DEREGISTERED state), or a mobility registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because the UE moves, or the UE wants to update its capabilities or protocol parameters, or because the UE requests a change in the set of network slices it is allowed to use), or a periodic registration update (i.e., the UE is in RM-REGISTERED state and the registration procedure is initiated because of expiration of the periodic registration update timer), or an emergency registration (i.e., the UE is in restricted service state).

[0172] When a UE performs initial registration, the UE indicates its UE ID in the registration request message, listed in decreasing priority order.

[0173] i) If the UE has a valid evolved packet system (EPS) globally unique temporary identifier (GUTI), 5G-GUTI mapped from the EPS GUTI;

[0174] ii) Native 5G-GUTI (if available) allocated by the PLMN in which the UE is attempting to register;

[0175] iii) Native 5G-GUTI allocated by a PLMN equivalent to the PLMN in which the UE is attempting to register;

[0176] iv) Native 5G-GUTI allocated by another PLMN (if available);

[0177] v) Otherwise, the UE includes a subscriber concealed identifier (SUCI) in the registration request message.

[0178] If a UE performing initial registration has both a valid EPS GUTI and a native 5G-GUTI, the UE also indicates the native 5G-GUTI as an additional GUTI. If more than one native 5G-GUTI is available, the UE selects a 5G-GUTI from items (ii)-(iv) in decreasing priority order in the list above.

[0179] When the UE performs initial registration with native 5G-GUTI, the UE indicates the relevant GUAMI information in the AN parameters. When the UE performs initial registration with SUCI, the UE does not indicate the GUAMI information in the AN parameters.

[0180] For emergency registration, if the UE does not have a valid 5G-GUTI, the SUCI is included. If the UE does not have a subscriber permanent identifier (SUPI) and does not have a valid 5G-GUTI, the PEI (Permanent Equipment Identifier) ​​is included. Otherwise, the 5G-GUTI is included, indicating the last serving AMF.

[0181] The registration request message may also include security parameters, PDU session status, etc. Security parameters are used for authentication and integrity protection. The PDU session status indicates a previously established PDU session in the UE. When the UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the PDU session status indicates the PDU session currently established in the PLMN in the UE.

[0182] (2) Step 2: (R)AN selects AMF.

[0183] If 5G-S-TMSI or GUAMI is not included, or if 5G-S-TMSI or GUAMI does not indicate a valid AMF, the (R)AN selects an AMF based on the (R)AT and the requested NSSAI, if available.

[0184] When the UE is in CM-CONNECTED state, (R)AN can forward a registration request message to AMF based on the UE's N2 connection.

[0185] If the (R)AN cannot select an appropriate AMF, the (R)AN performs AMF selection by forwarding a registration request message to the AMF configured in the (R)AN.

[0186] (3) Step 3: (R)AN sends a registration request message to the new AMF. The registration request message corresponds to the N2 message.

[0187] The registration request message may contain all of the information and / or part of the information contained in the registration request message received from the UE described in step 1.

[0188] The registration request message may include an N2 parameter. When NG-RAN is used, the N2 parameter includes the selected PLMN ID (or PLMN ID and NID), location information and cell ID related to the cell where the UE is camping, and a UE context request indicating that a UE context including security information should be established in the NG-RAN. When NG-RAN is used, the N2 parameter also includes an establishment cause.

[0189] If the registration type indicated by the UE is periodic registration update, steps 4-19 described below may be omitted.

[0190] (4) Step 4: If the UE's 5G-GUTI is included in the registration request message and the serving AMF has changed since the last registration procedure, the new AMF may invoke the Namf_Communication_UEContextTransfer service operation to the previous AMF, including the full registration request non-access stratum (NAS) message to request the UE's SUPI and UE context.

[0191] (5) Step 5: The old AMF can respond to the new AMF for the Namf_Communication_UEContextTransfer call including the UE's SUPI and UE context.

[0192] (6) Step 6: If SUCI is not provided by the UE or not retrieved from the previous AMF, the new AMF may initiate an ID request procedure by sending an Identity Request message to request SUCI from the UE.

[0193] (7) Step 7: The UE may respond with an Identity Response message including the SUCI. The UE derives the SUCI using the provided public key of the home PLMN (HPLMN).

[0194] (8) Step 8: The new AMF may decide to initiate UE authentication by calling the AUSF. In this case, the new AMF selects the AUSF based on SUPI or SUCI.

[0195] (9) Step 9: Authentication / security can be established by UE, new AMF, AUSF and / or UDM.

[0196] (10) Step 10: If the AMF has changed, the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation to notify the old AMF that the UE registration with the new AMF is complete. If the authentication / security procedure fails, the registration is rejected and the new AMF may call the Namf_Communication_RegistrationCompleteNotify service operation with a reject indication reason code to the old AMF. The old AMF may continue as if the UE context transfer service operation was not received.

[0197] (11) Step 11: If the PEI was not provided by the UE or was not retrieved from the previous AMF, the new AMF may initiate the ID request procedure by sending an Identity Request message to the UE to retrieve the PEI. The PEI is transmitted encrypted, except when the UE performs emergency registration and cannot be authenticated.

[0198] (12) Step 12: Optionally, the new AMF can initiate ME ID checking by calling the N5g-eir_EquipmentIdentityCheck_Get service operation.

[0199] Now, the procedure of Fig. 7 following the procedure of Fig. 6 is described.

[0200] (13) Step 13: If step 14 below is performed, the new AMF can select a UDM based on SUPI, and the UDM can select a UDR instance.

[0201] (14) Step 14: New AMFs can be registered with UDM.

[0202] (15) Step 15: New AMF can select PCF.

[0203] (16) Step 16: The new AMF may optionally perform AM policy association establishment / modification.

[0204] (17) Step 17: The new AMF can send update / release SM context messages (e.g., Nsmf_PDUSession_UpdateSMContext and / or Nsmf_PDUSession_ReleaseSMContext) to the SMF.

[0205] (18) Step 18: If the new AMF and the old AMF are in the same PLMN, the new AMF may send a UE context modification request to the N3IWF / TNGF / W-AGF.

[0206] (19) Step 19: N3IWF / TNGF / W-AGF may send a UE context modification response to the new AMF.

[0207] (20) Step 20: After the new AMF receives the response message from N3IWF / TNGF / W-AGF in step 19, the new AMF can register with UDM.

[0208] (21) Step 21: The new AMF sends a Registration Accept message to the UE.

[0209] The new AMF sends the UE a Registration Accept message indicating that the registration request has been accepted. If the new AMF allocates a new 5G-GUTI, it includes the 5G-GUTI. If the UE is already in the RM-REGISTERED state through another connection to the same PLMN, the UE uses the 5G-GUTI received in the Registration Accept message for both registrations. If the Registration Accept message does not include a 5G-GUTI, the UE uses the 5G-GUTI assigned to the existing registration for the new registration. If the new AMF allocates a new registration area, it sends the registration area to the UE in the Registration Accept message. If the Registration Accept message does not include a registration area, the UE considers the previous registration area to be valid. Mobility Restrictions are included if mobility restrictions apply to the UE and the registration type is not emergency registration. The new AMF indicates the PDU sessions established for the UE in the PDU Session State. The UE locally removes internal resources associated with PDU sessions that are not marked as established in the received PDU Session State. When a UE is connected to two AMFs belonging to different PLMNs via a 3GPP connection and a non-3GPP connection, the UE locally removes internal resources associated with PDU sessions in the current PLMN that are not marked as established in the received PDU session status. If PDU session status information is present in the Registration Accept message, the new AMF indicates the PDU session status to the UE.

[0210] The Allowed NSSAI provided in the Registration Accept message is valid for the registration area and applies to all PLMNs that have a tracking area included in the registration area. The Mapping of Allowed NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Allowed NSSAIs. The Mapping of Configured NSSAIs maps HPLMN S-NSSAIs to each S-NSSAI of the Configured NSSAI for the serving PLMN.

[0211] Additionally, optionally, the new AMF performs UE policy association establishment.

[0212] (22) Step 22: If the UE successfully updates itself, it can send a Registration Complete message to the new AMF.

[0213] The UE may send a registration complete message to the new AMF to confirm that a new 5G-GUTI has been allocated.

[0214] (23) Step 23: In case of registration via 3GPP connection, if the new AMF does not release the signaling connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN. In case of registration via non-3GPP connection, if the UE is in CM-CONTENED state on the 3GPP connection, the new AMF may send RRC Inactive Assistance information to the NG-RAN.

[0215] (24) Step 24: AMF can perform information updates on UDM.

[0216] (25) Step 25: The UE may execute a network slice-specific authentication and authorization (NSSAA) procedure.

[0217] <Non-Terrestrial Networks >

[0218] NTN (Non-Terrestrial Network) refers to a network or network segment that uses RF resources mounted on satellites (or UAS platforms).

[0219] There are two common scenarios for NTNs that provide access to user equipment: transparent payload and regenerative payload.

[0220] NTNs are typically characterized by the following elements:

[0221] - One or more sat-gateways connecting the NTN to the public data network.

[0222] - 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.

[0223] 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.

[0224] - Feeder link or wireless link between the satellite gateway and the satellite (or UAS platform).

[0225] - Service link or wireless link between user equipment and satellite (or UAS platform).

[0226] 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.

[0227] - Transparent payload: Radio frequency filtering, frequency conversion, and amplification. Therefore, the waveform signal repeated by the payload remains unchanged.

[0228] 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).

[0229] - 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.

[0230] - User equipment is serviced by satellites (or UAS platforms) within the target service area.

[0231] 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.

[0232] Describes S&F operation in relation to communications via satellite.

[0233] <S&F (Store and Forward)>

[0234] 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).

[0235] Figure 8 shows an example of basic satellite operation.

[0236] Figure 9 shows an example of S&F satellite operation.

[0237] Figures 8 and 9 illustrate examples of “S&F satellite operation” in contrast to current assumptions for “normal / default satellite operation” of a satellite-enabled 5G system.

[0238] 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 ground gateway.

[0239] - 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 active 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.

[0240] - 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 performed 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.

[0241] 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.

[0242] S&F satellite operation support may be particularly suitable for providing delay-tolerant / non-real-time IoT satellite services using NGSO satellites.

[0243] Transparent and regenerative payloads are:

[0244] - 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.

[0245] 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.

[0246] 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.

[0247] After a terminal is connected to a 5GC via a satellite, if the satellite (or terminal) moves out of the satellite's coverage, the terminal transitions to the CM-IDLE (RRC_IDLE) state. Subsequently, when the terminal enters coverage of the same satellite or another satellite, it must transition to the CM-CONNECTED (RRC_CONNECTED) state to transmit and receive signaling and data with the satellite.

[0248] When the satellite base station is equipped with only NG-RAN without additional core network functions, RRC_INACTIVE mode (RRC inactive state) can be used to ensure that the terminal remains in CM-CONNECTED state for communication.

[0249] While maintaining a CM-CONNECTED state with the core network, the terminal can utilize RRC_INACTIVE mode with the base station that manages terminal mobility. Then, when there is no data transmission or reception, the terminal operates in 'CM-CONNECTED with RRC_INACTIVE' mode, and when there is data transmission or reception, the terminal can transition to RRC-CONNECTED (RRC connected state) and operate.

[0250] Figure 10 shows an example of a process of transitioning from an RRC inactive state to an RRC connected state.

[0251] In a typical terrestrial network, when a terminal in an RRC inactive state sends an RRCResumeRequest to create an RRC connection with a new base station, the terminal includes the I-RNTI (Inactive Radio Network Temporary Identifier) ​​information allocated by the base station that last served the terminal.

[0252] A new base station that receives an RRCResumeRequest obtains UE context information from the base station that last served the terminal based on the base station ID included in the I-RNTI.

[0253] The new base station transmits a 'RETRIEVE UE CONTEXT REQUEST' to the previous serving base station to request UE context. Then, the previous serving base station transmits a 'RETRIEVE UE CONTEXT RESPONSE' containing the UE context to the new base station.

[0254] Based on this, the new base station transmits RRCResume to the terminal, and the terminal transitions to the RRC connected state.

[0255] After the new base station obtains the UE context from the previous serving base station, the new base station sends a UE CONTEXT RELEASE message. The previous serving base station then deletes the UE context.

[0256] Figure 11 shows an example of the situation at time T1.

[0257] Figure 12 shows an example of the situation at time T2.

[0258] Figure 13 shows an example of the situation at time T3.

[0259] S&F operations can be performed using the RRC inactive state.

[0260] For example, the following actions may be performed at time T1:

[0261] - The terminal can establish an RRC connection through initial registration with satellite A.

[0262] - The terminal can create a PDU session for data transmission.

[0263] - The terminal can transmit uplink MO (Mobile Originated) data.

[0264] - If satellite A is configured to buffer data, satellite A can buffer the data until it moves to a position where it can transmit using a direct feeder link instead of sending the data directly to the AMF. After this, the terminal can enter the RRC inactive (RRC_INACTIVE) state.

[0265] For example, the following actions may be performed at time T2:

[0266] - The satellite (or terminal) may move and the terminal may move out of the coverage of satellite A.

[0267] - The terminal can perform periodic registration by connecting to satellite B. To do this, the terminal can issue an RRC resume request. Based on this, satellite B can retrieve the UE context from satellite A, where it was storing the UE context. Then, the terminal can transition to the RRC connected (RRC_CONNECTED) state and perform the registration process.

[0268] - Satellite B sends a UE context release message to satellite A to delete the UE context according to the existing operation. Then, satellite A deletes the UE context while it is not yet connected to the ground gateway (base station) and thus cannot transmit the terminal's uplink data. The terminal transitions to the RRC inactive (RRC_INACTIVE) state. Afterwards, satellite A connects to the ground gateway at time T3. Since the UE context has been deleted, satellite A cannot transmit uplink data (e.g., NAS signaling) to the AMF through the ground gateway.

[0269] For S&F operation, satellite A must be able to transmit uplink data from the terminal to the ground gateway when connected to the ground gateway.

[0270] In order to perform S&F operation in the RRC inactive state of the terminal, a method is needed to not delete the UE context even after satellite A transmits it to satellite B.

[0271] S&F operations can be used in delay-tolerant data communications due to the time delay involved. Therefore, the aforementioned method (not deleting the UE context) is only required for terminals performing delay-tolerant data communications, thus distinguishing them from general terminals.

[0272] In this specification, a method for managing a UE context of a satellite for a terminal and a network supporting S&F operation may be proposed.

[0273] The UE context management method of the base station for the storage and transmission operation of the proposed satellite may be composed of a combination of one or more of the following operations / configurations / steps.

[0274] These procedures and / or messages may use existing procedures / messages, may extend existing procedures / messages, or may define and use new procedures / messages.

[0275] In this specification, Store and Forward (S&F) and storage and forward are used interchangeably.

[0276] In this specification, UE (User Equipment) and terminal are used interchangeably.

[0277] This specification mainly describes the proposed content.

[0278] In this specification, the satellite may be a regenerative satellite.

[0279] This specification assumes a structure in which NG-RAN is mounted on a satellite.

[0280] In this specification, connection may mean logical association and / or physical association.

[0281] When the satellite serving a terminal changes, the terminal can establish an RRC connection with the new satellite through registration. This RRC connection establishment procedure can be implemented through an inter-satellite link (ISL) between satellites. Depending on the implementation method, an Xn interface can be raised on the ISL so that the base station can relay NAS signals. Alternatively, the ISL can be used as a transport layer to implement a direct N2 interface between the satellite and the AMF.

[0282] Through registration, the core network can receive the UE context of the terminal.

[0283] AMF can set a periodic registration timer for the terminal based on satellite coverage information. Based on this, the terminal can perform registration whenever the satellite changes.

[0284] In this specification, it is assumed and described that the Xn interface between satellites is implemented via ISL and that each satellite transmits signaling to the AMF via the Xn interface. To this end, it is assumed that each satellite has routing information for transmitting signaling to the AMF.

[0285] Alternatively, the satellite can establish a direct N2 interface via a multi-hop ISL between the satellite and the AMF.

[0286] For S&F operations, we assume that IoT terminals are not mobile. Alternatively, even if the terminals are mobile, we assume that the network (e.g., AMF) can determine when the terminal enters satellite coverage based on information about the terminal's mobility.

[0287] Satellites may have an inter-satellite Xn interface via ISL. Terminals can register and create PDU sessions via ISL. Terminals can transmit data via S&F mode.

[0288] Data transmission in this specification may be data transmission through the Control Plane via Control Plane 5GS CIoT Optimisation operations.

[0289] When a terminal transmits data through the control plane in an RRC connection (RRC_CONNECTED) state, the satellite NG-RAN cannot know whether the UL NAS Transport message included in the RRC message includes user data. Therefore, the terminal can include an indication indicating whether user data is included in the RRC message.

[0290] A satellite can operate in an RRC inactive state (RRC_INACTIVE mode) for a specific terminal. In this state, the satellite can retrieve the UE context from the NG-RAN that contains the UE context for the specific terminal. This then transitions to an RRC connected state. After this, the terminal and satellite can transmit and receive data.

[0291] Figure 14 shows an example of an Xn setting procedure according to an embodiment of the present specification.

[0292] Base station node 1 can send an XN SETUP REQUEST message to base station node 2. Based on this, base station node 2 can send an XN SETUP RESPONSE message to base station node 1. At this time, the two satellites can exchange the necessary configuration data on the Xn interface.

[0293] If base station node 1 (satellite) supports S&F operation, base station node 1 can transmit to node 2 information about its capability to support S&F operation in an XN SETUP REQUEST message.

[0294] Similarly, if base station node 2 (satellite) supports S&F operation, base station node 2 may transmit to base station node 1 information about its capability to support S&F operation in the XN SETUP RESPONSE message.

[0295] Base station node 1 and base station node 2 can inform each other whether they support S&F operation.

[0296] To include the aforementioned capabilities in the XN SETUP REQUEST (or XN SETUP RESPONSE) message, a new IE can be defined (e.g., List of Served Cells NR IE > Served Cell Information NR IE > Store and Forward Supported IE).

[0297] Figure 15 shows an example of an NG setting procedure according to an embodiment of the present specification.

[0298] The NG setup process between the satellite (base station) and AMF can be performed.

[0299] A satellite can send an NG SETUP REQUEST message to the AMF. Based on this, the AMF can send an NG SETUP RESPONSE message to the satellite. This process allows the exchange of necessary configuration data on the NG interface.

[0300] If a satellite supports S&F operation, the satellite may transmit to the AMF information about its capability to support S&F operation in the NG SETUP REQUEST message.

[0301] If the AMF supports S&F operation, the AMF may transmit to the satellite information about its capability to support S&F operation in the NG SETUP RESPONSE message.

[0302] The satellite and AMF can inform each other whether S&F operation is supported.

[0303] To include the aforementioned capabilities in the NG SETUP REQUEST (or NG SETUP RESPONSE) message, a new IE may be defined.

[0304] If both the satellite and the AMF support S&F operation, multiple N2 connections may be created between the satellite and the AMF for terminals that support S&F operation.

[0305] That is, even if an N2 connection for a specific terminal exists between the satellite and the AMF, an additional N2 connection for the specific terminal may be created between the satellite and the AMF.

[0306] Figure 16 illustrates an example of a registration procedure according to an embodiment of the present specification.

[0307] The general overall registration process can be applied to TS 23.502 v18.2.0, 4.2.2.2.2 General Registration or Figures 6-7.

[0308] According to an embodiment of the present specification, information indicating that S&F operation is supported may be transmitted to a base station (satellite). The base station (satellite) may add the aforementioned information to the UE context.

[0309] Step 1. The terminal may be within the coverage of satellite A.

[0310] The terminal can be connected to a ground network (ground gateway and / or core network) via satellite A.

[0311] The terminal can perform registration with the core network via satellite A.

[0312] The terminal can be connected to the terrestrial network via the ISL between satellite A and satellite B.

[0313] Step 2. The terminal can send a registration request message to AMF via satellite A to register with the network.

[0314] The terminal can transmit information that it can operate in S&F mode to AMF via satellite A by including it in the 'Core Network MM capability' of the registration request message.

[0315] Step 3. Steps 2-9 of 4.2.2.2.2 General Registration of TS 23.502 v18.2.0 (or Figures 6 and 7) can be performed.

[0316] Step 4. In step 9 of 4.2.2.2.2 General Registration of TS 23.502 v18.2.0 (or FIGS. 6 and 7), the AMF performs the initial context setup process with the NG-RAN. At this time, the AMF may transmit information to the NG-RAN (satellite A and satellite B) that the terminal supports S&F operation.

[0317] Step 5. Satellite A can store in the UE context that it is a terminal that supports S&F operation (operates in S&F mode). This information can be transmitted to a new satellite (or base station) even if the satellite (or base station) is changed.

[0318] Step 6. Steps 10-25 of 4.2.2.2.2 General Registration of TS 23.502 v18.2.0 (or Figures 6 and 7) may be performed. In step 21, the AMF may send the terminal information that it supports the S&F operation in the Registration Accept message.

[0319] MO (mobile originated) data (uplink data) can be transported using the 'UPF anchored Mobile Originated Data Transport in Control Plane CIoT 5GS Optimisation' method of TS 23.502 v18.2.0, clause 4.24.1 for S&F, or can be transported via the general user plane.

[0320] Data buffering in this specification may be performed by the satellite's base station (NG-RAN).

[0321] Satellite A, Satellite B and AMF can all support S&F operation.

[0322] An example using Control Plane CIoT 5GS Optimization is as follows:

[0323] - A terminal that has registered with the network and created a PDU session can transmit MO data to satellite B. Here, satellite B may be a satellite that does not have a direct connection to the terrestrial network through a feeder link.

[0324] - Satellite B can store MO data from the terminal.

[0325] - After this, when the feeder link between Satellite B and the ground network is connected, Satellite B can transmit MO data to the ground network.

[0326] - Satellite C can obtain the UE context for the terminal from satellite B.

[0327] - Satellites A, B, and C can all maintain their UE contexts without deleting them.

[0328] - Even if the satellite serving the terminal changes, the terminal can transmit MO data by connecting to the changed satellite.

[0329] Figures 17 and 18 illustrate examples of S&F procedures according to embodiments of the present specification.

[0330] Steps 1 to 5 described below may correspond to T1 of Fig. 11.

[0331] Steps 6 to 12 described below may correspond to T2 of Fig. 12.

[0332] Step 13 and thereafter described below may correspond to T3 of Fig. 13.

[0333] Step 1-2. Same as Step 1-6 of Fig. 16. After this, the terminal can enter CM-CONNECTED and RRC_CONNECTED states.

[0334] Step 3. The terminal can create a PDU session according to the PDU session establishment procedure in 4.3.2.2.1 of TS 23.502 v18.2.0. In this procedure, the AMF can decide to use Control Plane CIoT 5GS Optimization.

[0335] Step 4. If the terminal has MO data, the terminal can transmit the PDU session ID and MO data used for Control Plane CIoT 5GS Optimization to Satellite A in the NAS message (UL NAS Transport).

[0336] The terminal can transmit MO data to satellite A. The MO data can include a PDU session ID.

[0337] Step 5. If there is no current feeder link to Satellite A and the terminal supports S&F operation, Satellite A can store the MO data of the terminal.

[0338] Satellite A can determine whether the terminal supports S&F operations through the UE context. Support for S&F operations by the terminal may indicate that there are no issues with communications via S&F operations. For example, this may be the case if the terminal is performing delay-tolerant networking.

[0339] Step 6. The terminal can transition to the RRC inactive (RRC_INACTIVE) state.

[0340] Based on the absence of data for the terminal (MO data and / or MT data), the terminal may transition to the RRC inactive (RRC_INACTIVE) state.

[0341] Alternatively, if the terminal is no longer within the coverage of satellite A (due to movement of the terminal / satellite), the terminal may transition to the RRC inactive (RRC_INACTIVE) state.

[0342] (Due to movement of the terminal or satellite A) the satellite serving the terminal may change from satellite A to satellite B. That is, (due to movement of the terminal or satellite A) the terminal may be located in the coverage of satellite B rather than the coverage of satellite A.

[0343] The terminal may be in an RRC connected state within the coverage of satellite A. After this, the terminal may enter an RRC inactive state. After this, the terminal may be in an RRC connected state within the coverage of satellite B.

[0344] Step 7. According to the periodic registration cycle, the terminal can send an RRC Resume Request (RRCResumeRequest) (9.2.2.4.1 of TS 38.300 v17.5.0) message to satellite A to trigger the registration procedure. Based on this, the RRC resume procedure can be performed.

[0345] Step 8. Satellite B can verify the base station ID (the ID corresponding to satellite A) through the UE's I-RNTI information and obtain the UE context from satellite A.

[0346] Satellite B can obtain UE context through ISL with satellite A.

[0347] Satellite B may send a RETRIEVE UE CONTEXT REQUEST message to satellite A. Based on this, satellite A may send a RETRIEVE UE CONTEXT RESPONSE message to satellite B.

[0348] The RETRIEVE UE CONTEXT RESPONSE message may include a UE context. The UE context may include information that the terminal supports S&F operations.

[0349] Step 9. Once RRC resumption is complete, the terminal can enter the RRC connected (RRC_CONNECTED) state.

[0350] Satellite B can transmit an RRC Resume to the terminal. Then, the terminal can enter the RRC connected (RRC_CONNECTED) state.

[0351] Step 10. The terminal can send an RRC resumption complete (RRCResumeComplete) message to satellite B.

[0352] At this time, the RRC Resume Complete message may include a Registration Request for periodic registration of the terminal.

[0353] The terminal can be in CM-CONNECTED or RRC_CONNECTED state.

[0354] Step 11. Satellite B may decide not to send a UE CONTEXT RELEASE message to satellite A. This decision may be based on the fact that satellite A and the terminal support S&F operations.

[0355] Previously, after the RRC resume complete (RRCResumeComplete) procedure, satellite B transmitted a UE context release (UE CONTEXT RELEASE) message to satellite A. Then, the process of deleting the UE context in satellite A was performed.

[0356] Based on the following, Satellite B may decide not to send a UE CONTEXT RELEASE message to Satellite A:

[0357] - Based on the UE context information acquired (from satellite A), satellite B can know that the terminal supports S&F operation.

[0358] - When satellite B and satellite A perform Xn setup (Fig. 14), satellite B can know that satellite A supports S&F operation.

[0359] Based on not receiving a UE CONTEXT RELEASE message from satellite B, satellite A may maintain the UE context and buffered terminal data without deleting them.

[0360] Step 12. The terminal can perform a periodic registration procedure through satellite B.

[0361] Periodic registration procedures can be performed via the service link between the terminal and satellite B and the feeder link between satellite B and the ground gateway.

[0362] i) A terminal can perform a periodic registration procedure through a service link between the terminal and satellite B, ii) an ISL between satellite B and another satellite (e.g., satellite C), and iii) a feeder link between another satellite and a ground gateway.

[0363] AMF can determine that the terminal supports S&F operation through the UE context (the UE context of AMF) (through the information received from the terminal during the registration process in step 2 that the terminal supports S&F operation). Based on this, AMF can determine multiple N2 connections.

[0364] That is, AMF can create an additional N2 connection with satellite B while maintaining the N2 connection with satellite A.

[0365] Step 13. Once Satellite A is connected to the ground network, it can decide to transmit the buffered data over the feeder link.

[0366] If Satellite A can connect to the ground gateway, Satellite A can connect to the core network (e.g., AMF) via the ground gateway (feeder link) using the UE context. That is, Satellite A can connect to the AMF using the maintained N2 connection (i.e., without performing the NG setup procedure).

[0367] Satellite A can connect to the UE's AMF using the maintained UE context.

[0368] Step 14. Satellite A can forward the NAS message (UL NAS Transport) received from the terminal to the AMF. The NAS message can include the terminal's MO data and PDU session ID from step 4.

[0369] Using the N2 connection maintained in step 12 (i.e., without performing the NG setup procedure) and the UE context, satellite A can transmit the buffered data to the AMF over the feeder link once it is connected to the ground network. The buffered data may include the PDU session ID.

[0370] Step 15. AMF can determine which SMF handles the PDU session based on the PDU session ID included in the NAS message. Based on this, AMF can forward the PDU session ID and data to the SMF that determined it through the Nsmf_PDUSession_SendMOData service operation.

[0371] Step 16. SMF can forward data received from AMF to UPF.

[0372] Even if a satellite has no uplink data (MO data) or downlink data (MT data), it can retain its UE context without deleting it. The retained UE context can be used when the satellite returns to serving a terminal (e.g., after returning to orbit and serving a terminal again).

[0373] A UE context can be deleted after a certain period of time by a timer. The timer can be set by the terminal, satellite, base station, or core network.

[0374] When Control Plane CIoT 5GS Optimization is not used, in step 4 of FIG. 17, instead of transmitting user data via a NAS message (UL NAS Transport) containing a PDU session ID and data, the terminal can transmit MO data to satellite A via the user plane. Satellite A can store the MO data.

[0375] In this case, after step 10 of FIG. 17, satellite B may transmit a Path Switch Request message to AMF. Satellite B may include an indication in the Path Switch Request that it supports S&F operation.

[0376] Based on the above indication and / or the fact that the terminal supports S&F operation, the AMF may maintain the N2 connection with satellite A for the terminal without deleting it.

[0377] After this, satellite A can connect to the ground gateway (feeder link) (step 13 in Figure 17). Then, satellite A can connect to the AMF using the maintained N2 connection (i.e., without performing the NG setup procedure) and the UE context. Satellite A can send a Path Switch Request message to the AMF. Then, satellite A can create UPF and user plane resources through the SMF and forward the stored MO data to the UPF.

[0378] A satellite (a satellite equipped with a base station function) can receive information from the AMF that the terminal supports S&F operation during the registration process and store the information in the UE context. If the satellite serving the terminal changes, the UE context including the information can be transferred to the changed serving satellite (the satellite currently serving the terminal). The changed serving satellite may not send a UE context release message to the previous serving satellite based on the UE context. Accordingly, the previous serving satellite can connect to the terminal's AMF using the UE context when it is connected to the ground gateway later without deleting the UE context. Based on this, the previous serving satellite can forward the buffered MO data to the AMF.

[0379] S&F operation can be supported in RRC inactive state (RRC_INACTIVE mode).

[0380] The operations proposed in this specification can be applied by the NG-RAN and AMF mounted on the satellite to terminals performing S&F operations of the satellite.

[0381] Satellites may be equipped with NG-RAN. Terminals supporting S&F operations may not have mobility. Alternatively, even if the terminals are mobile, the network (e.g., AMF) can determine when the terminal enters satellite coverage based on information about the terminal's mobility.

[0382] Satellites can communicate with each other via the Xn interface over the ISL. Signaling messages, such as terminal registration to the network or creation of a PDU session, can be transmitted to the gateway (base station) via the ISL. Terminal data transmission can be performed via the S&F.

[0383] The proposed behavior can be used both when using a generic user plane and when transmitting data as NAS messages via 'Control Plane CIoT 5GS Optimization'. The terminal can include an indication in the RRC message indicating whether user data is included.

[0384] The satellite can be a LEO or MEO satellite.

[0385] 1) Satellites can exchange capability information on whether S&F operation is supported by each other during the Xn setup process to determine whether they support each other. Satellites can exchange capability information on whether S&F operation is supported by each other during the NG setup process between AMFs to determine whether they support each other. If both the satellite and the AMF support the function, multiple N2 connections between the AMF and the satellite base station can be created and maintained for one UE that supports the S&F function.

[0386] 2) During the process of registering with the network, the terminal can indicate that it is a terminal that can support S&F operation, and the satellite's AMF can also accept the S&F operation. When creating an initial context with the satellite NG-RAN, the AMF can indicate in the UE context that the UE is operating in S&F mode, or can include in the UE context that the UE is operating in S&F mode. The RAN can store in the UE context that the UE is operating in S&F mode. This information can be transmitted to a new satellite (or base station) even when the satellite (or base station) is changed.

[0387] 3) If there is no data to transmit, the terminal transitions to the RRC inactive (RRC_INACTIVE) state, and the satellite NG-RAN can maintain the UE context of the terminal.

[0388] 4) When a satellite moves and the satellite covering the terminal changes and the terminal performs an RRC resume process, the new satellite NG-RAN can retrieve the UE context from the satellite that previously had the UE context of the terminal. The new satellite can confirm that the corresponding UE supports the S&F function from the UE context in the RETRIEVE UE CONTEXT RESPONSE message. The new satellite can confirm that the satellite supports the S&F operation during the Xn Setup process with the satellite that delivered the UE context. Based on the fact that the existing satellite and the UE support the S&F operation, the new satellite can decide not to deliver a UE CONTEXT RELEASE message to the existing satellite.

[0389] 5) If the satellite servicing the terminal changes, the original satellite can maintain the UE context even if it transfers the UE context to the new satellite. Based on this, the original satellite can connect to the UE's AMF using the stored UE context when connected to the ground gateway. In addition, if the original satellite stored the UE's MO data, it can transmit the UE's MO data to the UE's AMF.

[0390] 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 / 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.

[0391] Figure 19 illustrates the procedure of the first satellite for the disclosure of this specification.

[0392] 1. The first satellite can receive a registration request message from a UE (User Equipment).

[0393] The above registration request message may include UE capability information indicating that the UE supports S&F (Store and Forward).

[0394] 2. The first satellite can transmit the above registration request message to the AMF (Access and Mobility management Function).

[0395] 3. The first satellite can receive an initial context setup message from the AMF.

[0396] The above initial context setup message may include the UE capability information.

[0397] 4. Based on the initial context setup message, the first satellite can store the UE capability information as a UE context for the UE.

[0398] 5. The first satellite can receive data from the UE.

[0399] 6. i) The first satellite is not connected to the ground gateway and ii) based on the UE capability information, the first satellite can store the data.

[0400] 7. The first satellite can transmit satellite support information indicating that the first satellite supports S&F to the second satellite through an Xn setup procedure with the second satellite.

[0401] 8. Based on the satellite serving the UE being changed from the first satellite to the second satellite, the first satellite can receive a request for the UE context from the second satellite.

[0402] 9. Based on the above request, the first satellite can transmit the UE context to the second satellite.

[0403] 10. Based on transmitting the above UE context, the first satellite can receive a UE context release message from the second satellite.

[0404] 11. Based on the above UE context release message, the first satellite can delete the UE context.

[0405] i) Based on transmitting the satellite support information and ii) based on the UE capability information, the first satellite may skip receiving the UE context release message from the second satellite and deleting the UE context.

[0406] The first satellite can connect to a specific ground gateway.

[0407] Based on skipping the deletion of the UE context, the first satellite can transmit the data to the AMF via the specific ground gateway using the UE context.

[0408] The first satellite can perform the procedure for establishing a PDU session with the UE and the AMF.

[0409] The above data may be related to the above PDU session.

[0410] The above data may include an ID of the PDU session.

[0411] The above first satellite may be a regenerative satellite.

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

[0413] Figure 20 illustrates the AMF's procedure for disclosure of this specification.

[0414] 1. AMF can receive a first registration request message from UE (User Equipment) via the first satellite.

[0415] The above registration request message may include UE capability information indicating that the UE supports S&F (Store and Forward).

[0416] 2. AMF may transmit an initial context setup message to the first satellite.

[0417] The above initial context setup message may include the UE capability information.

[0418] 3. Based on the first registration request message, the AMF can send a first registration request approval message to the UE.

[0419] The above first registration request approval message may include information that the AMF supports S&F.

[0420] 4. Based on the satellite serving the UE being changed from the first satellite to the second satellite, the AMF can receive a second registration request message from the UE through the second satellite.

[0421] 5. Based on i) the first satellite supports S&F, ii) the first satellite is connected to a ground gateway, iii) the first satellite received and stored data from the UE before the change, and iv) the UE capability information, the AMF can receive the data from the first satellite through the ground gateway.

[0422] AMF can perform a procedure for establishing a PDU session with the UE and the first satellite.

[0423] The above data may be related to the above PDU session.

[0424] The above data may include an ID of the PDU session.

[0425] AMF can transmit the above data to SMF based on the ID of the above PDU session.

[0426] The above first satellite may be a regenerative satellite.

[0427] 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 / 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.

[0428] Figure 21 illustrates the UE's procedure for disclosure of this specification.

[0429] 1. The UE can transmit a first registration request message to the first satellite.

[0430] The above first satellite may not be connected to a ground gateway.

[0431] The above registration request message may include UE capability information indicating that the UE supports S&F (Store and Forward).

[0432] 2. The UE can receive a registration approval message from the Access and Mobility management Function (AMF).

[0433] 3. The UE can perform the procedure for establishing a PDU session with the first satellite and the AMF.

[0434] 4. The UE can transmit data to the first satellite through the PDU session.

[0435] 5. Based on the satellite serving the UE being changed from the first satellite to the second satellite, the UE may transmit a second registration request message to the second satellite.

[0436] The above first satellite may be a regenerative satellite.

[0437] Hereinafter, a device for performing communication according to some embodiments of the present specification will be described.

[0438] For example, a device may include a processor, a transceiver, and memory.

[0439] For example, a processor may be configured to be operatively coupled with memory and a processor.

[0440] The operations performed by the above processor include: transmitting a first registration request message to a first satellite;

[0441] The first satellite has no connection to a ground gateway, and the registration request message includes UE capability information indicating that the UE supports S&F (Store and Forward), and may include the steps of: receiving a registration approval message from an AMF (Access and Mobility management Function); performing a procedure for establishing a PDU session with the first satellite and the AMF; transmitting data to the first satellite through the PDU session; and transmitting a second registration request message to the second satellite based on the fact that the satellite serving the UE has changed from the first satellite to the second satellite.

[0442] Below, a processor of a device for providing communication according to some embodiments of the present specification is described.

[0443] The operations performed by the processor may include: transmitting a first registration request message to a first satellite; the first satellite has no connection with a ground gateway, the registration request message includes UE capability information indicating that the UE supports Store and Forward (S&F), and receiving a registration approval message from an Access and Mobility Management Function (AMF); performing a procedure for establishing a PDU session with the first satellite and the AMF; transmitting data to the first satellite through the PDU session; and transmitting a second registration request message to the second satellite based on the fact that the satellite serving the UE has changed from the first satellite to the second satellite.

[0444] 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.

[0445] 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.

[0446] 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.

[0447] Computer-readable media may include tangible and non-volatile computer-readable storage media.

[0448] 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.

[0449] 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.

[0450] 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.

[0451] One or more stored commands comprise the step of transmitting a first registration request message to a first satellite;

[0452] The first satellite has no connection to a ground gateway, and the registration request message includes UE capability information indicating that the UE supports S&F (Store and Forward), and may include the steps of: receiving a registration approval message from an AMF (Access and Mobility management Function); performing a procedure for establishing a PDU session with the first satellite and the AMF; transmitting data to the first satellite through the PDU session; and transmitting a second registration request message to the second satellite based on the fact that the satellite serving the UE has changed from the first satellite to the second satellite.

[0453] This specification may have various effects.

[0454] For example, S&F operations may be performed when the serving satellite changes.

[0455] 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.

[0456] 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 for the first satellite to perform communication, A step of receiving a registration request message from a UE (User Equipment); The above registration request message includes UE capability information indicating that the UE supports S&F (Store and Forward), A step of sending the registration request message to AMF (Access and Mobility management Function); A step of receiving an initial context setup message from the AMF; The above initial context setup message includes the UE capability information, A step of storing the UE capability information as a UE context for the UE based on the initial context setup message; A step of receiving data from the UE; i) a step of storing the data based on the first satellite not being connected to a ground gateway and ii) the UE capability information; A step of transmitting satellite support information indicating that the first satellite supports S&F from the second satellite through an Xn setup procedure with the second satellite; A step of receiving a request for the UE context from the second satellite based on the satellite serving the UE being changed from the first satellite to the second satellite; A step of transmitting the UE context to the second satellite based on the above request; A step of receiving a UE context release message from the second satellite based on transmitting the UE context; A step of deleting the UE context based on the UE context release message, i) A method for transmitting the satellite support information and ii) skipping receiving the UE context release message from the second satellite and deleting the UE context based on the UE capability information.

2. In paragraph 1, Steps to connect to a specific ground gateway; A method further comprising the step of transmitting the data to the AMF via the specific ground gateway using the UE context based on skipping deleting the UE context.

3. In paragraph 2, Further comprising a step of performing a procedure for establishing a PDU session with the UE and the AMF, The above data is related to the above PDU session, A method wherein the above data includes an ID of the PDU session.

4. In any one of the clauses 1 to 3, The above first satellite is a regenerative satellite.

5. AMF (Access and Mobility management Function) is a method for performing communication. A step of receiving a first registration request message from a UE (User Equipment) via a first satellite; The above registration request message includes UE capability information indicating that the UE supports S&F (Store and Forward), A step of transmitting an initial context setup message to the first satellite; The above initial context setup message includes the UE capability information, A step of transmitting a first registration request approval message to the UE based on the first registration request message; The above first registration request approval message includes information that the AMF supports S&F, A step of receiving a second registration request message from the UE through the second satellite based on the satellite serving the UE being changed from the first satellite to the second satellite; A method comprising: i) the first satellite supporting S&F, ii) the first satellite being connected to a ground gateway, iii) the first satellite receiving and storing data from the UE prior to the change, and iv) receiving the data from the first satellite through the ground gateway based on the UE capability information.

6. In paragraph 5, A step of performing a procedure for establishing a PDU session with the UE and the first satellite; The above data is related to the above PDU session, The above data includes the ID of the PDU session, A method further comprising the step of transmitting the data to the SMF based on the ID of the PDU session.

7. In either of paragraphs 5 or 6, The above first satellite is a regenerative satellite.

8. A method by which UE (User Equipment) performs communication, A step of transmitting a first registration request message to the first satellite; The above first satellite has no connection to the ground gateway, The above registration request message includes UE capability information indicating that the UE supports S&F (Store and Forward), A step of receiving a registration approval message from AMF (Access and Mobility management Function); A step of performing a procedure for establishing a PDU session with the first satellite and the AMF; A step of transmitting data to the first satellite through the PDU session; A method comprising the step of transmitting a second registration request message to the second satellite based on the satellite serving the UE being changed from the first satellite to the second satellite.

9. In paragraph 8, The above first satellite is a regenerative satellite.

10. As the first satellite to perform communications, At least one transmitter and receiver; Contains at least one processor, The operation performed by the above processor is a first satellite according to any one of claims 1 to 4.

11. As an AMF (Access and Mobility 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 AMF method according to any one of claims 5 to 7.

12. As a UE (User Equipment) performing communication, At least one transmitter and receiver; Contains at least one processor, The operation performed by the above processor is a UE according to claim 8 or 9.

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