Apparatus and method for providing cellular and non-cellular communication services by using low orbit satellite

Abstract

Provided in embodiments of the present disclosure is a location management apparatus for registering and managing terminal-specific location-related information. The location management apparatus may comprise: a memory for storing instructions; at least one processor; and a communication circuit. When executed by the at least one processor, the instructions may cause the location management apparatus to: receive, through the communication circuit, an inquiry message requesting the location of a terminal; in response to the inquiry message, determine whether a table for storing terminal-specific location-related information in the memory includes the location-related information of the terminal; according to a determination that the table includes the location-related information of the terminal, transmit, through the communication circuit, a response message including the location-related information of the terminal to a node that has transmitted the inquiry message; and, according to a determination that the table does not include the location-related information of the terminal, transmit, through the communication circuit, an error response message to the node that has transmitted the inquiry message. The table can be used to store location-related information of the terminal accessing a cell provided by a base station providing a terrestrial network, and location-related information of the terminal accessing a cell provided by a satellite providing a non-terrestrial network.

Description

Device and method for providing cellular and non-cellular communication services using a low-orbit satellite

[0001] The present disclosure generally relates to a non-terrestrial network (NTN) that provides wireless communication services via a satellite located in Earth's orbit or an aerial vehicle flying at a high altitude, rather than a ground-based base station. More specifically, the present disclosure relates to an apparatus and method for providing cellular and non-cellular communication services using a low-orbit satellite.

[0002] Non-terrestrial networks (NTNs) have been introduced to complement terrestrial networks that provide wireless communication systems. NTNs can provide communication services even in areas where it is difficult to establish terrestrial networks or in disaster situations. Furthermore, due to the recent reduction in satellite launch costs, access network environments can be provided efficiently.

[0003] In embodiments of the present disclosure, a location management device configured to register and manage location-related information for each terminal is provided. The location management device may include a memory for storing instructions; at least one processor; and a communication circuit. When the instructions are executed by the at least one processor, the location management device may receive a query message requesting the location of a terminal through the communication circuit, and in response to the query message, determine whether a table configured to store location-related information for each terminal in the memory contains location-related information for the terminal, and, in accordance with the determination that the table does not contain location-related information for the terminal, transmit a response message containing location-related information for the terminal through the communication circuit to a node that transmitted the query message, and in accordance with the determination that the table does not contain location-related information for the terminal, cause an error response message to be transmitted through the communication circuit to a node that transmitted the query message. The table may be used to store location-related information for a terminal connected to a cell provided by a base station providing a terrestrial network and location-related information for a terminal connected to a cell provided by a satellite providing a non-terrestrial network.

[0004] In embodiments of the present disclosure, a network entity is provided for determining one or more inter-satellite links (ISLs) that are deployed on the ground. The network entity may include a memory for storing instructions; at least one processor; and a satellite communication circuit. When the instructions are executed by the at least one processor, the network entity may identify a start terminal and a destination terminal, and if the start terminal is connected to a first satellite and the destination terminal is connected to a second satellite, determine at least one candidate ISL path for connecting the first satellite and the second satellite, each of the at least one candidate ISL path includes one or more ISLs, determine whether the at least one candidate ISL path includes an ISL path in which all ISLs have links between satellites in the same orbital plane, and, upon the determination that the at least one candidate ISL path includes the ISL path, cause a message to be transmitted through the satellite communication circuit to an access satellite connected to the network entity to establish a data transmission path along the ISL path.

[0005] In embodiments of the present disclosure, a method is provided by a location management device configured to register and manage location-related information for each terminal. The method may include: receiving an inquiry message requesting the location of a terminal; in response to the inquiry message, determining whether a table configured to store location-related information for each terminal in the location management device includes location-related information for the terminal; transmitting a response message containing location-related information for the terminal to a node that transmitted the inquiry message in accordance with the determination that the table includes location-related information for the terminal; and transmitting an error response message to a node that transmitted the inquiry message in accordance with the determination that the table does not include location-related information for the terminal. The table may be used to store location-related information for a terminal connected to a cell provided by a base station providing a terrestrial network and location-related information for a terminal connected to a cell provided by a satellite providing a non-terrestrial network.

[0006] In embodiments of the present disclosure, a method is provided to be performed by a network entity deployed on the ground for determining one or more inter-satellite links (ISLs). The method may include the operation of identifying a starting terminal and a destination terminal; the operation of determining at least one candidate ISL path for connecting the first satellite and the second satellite when the starting terminal is connected to a first satellite and the destination terminal is connected to a second satellite; the operation of determining whether each of the at least one candidate ISL path includes one or more ISLs and whether the at least one candidate ISL path includes an ISL path in which all ISLs have links between satellites in the same orbital plane; and the operation of transmitting a message to an access satellite connected to the network entity to establish a data transmission path according to the ISL path in accordance with the determination that the at least one candidate ISL path includes the ISL path.

[0007] Figure 1 shows an example of a communication environment for DTC (direct to cell).

[0008] Figures 2a and 2b show examples of satellites moving along orbits.

[0009] Figure 3 shows an example of a communication link between satellites.

[0010] Figure 4 shows an example of a communication environment for communication scenarios using a satellite.

[0011] Figures 5a and 5b show examples of signaling of network entities in a first communication scenario using a satellite.

[0012] Figures 6a and 6b show examples of signaling of network entities in a second communication scenario using a satellite.

[0013] Figure 7 shows an example of signaling of network entities in a third communication scenario using a satellite.

[0014] Figures 8a and 8b show examples of signaling of network entities in a fourth communication scenario using a satellite.

[0015] Figure 9 shows the operation flow of a satellite for establishing a satellite path.

[0016] Figure 10 shows the operation flow of an Earth ground station for setting a satellite path.

[0017] Figure 11 shows the flow of operations of an Earth ground station for selecting a satellite.

[0018] Figure 12 shows the operation flow of a satellite for selecting an Earth ground station.

[0019] Figure 13 shows examples of the components of a satellite.

[0020] Figure 14 shows examples of the components of a ground station.

[0021] Figure 15 shows examples of components of a location management device.

[0022] Figure 16 is a flowchart illustrating an AI (artificial) / ML (machine learning)-based dynamic location prediction method for a location management device.

[0023] Figure 17 shows a flowchart of the security-enhanced location sharing operation of a location management device.

[0024] FIG. 18 is a flowchart illustrating the detailed operation of blockchain-based node authentication as depicted in step S1710 of FIG. 17.

[0025] Figure 19 is a flowchart illustrating a Regenerative Payload linked Inter-Satellite Link (ISL) optimization method.

[0026] Figure 20 is a block diagram showing the extended hardware configuration of a location management device.

[0027] Figure 21 is a block diagram showing the satellite network architecture and the main interfaces between each component.

[0028] Figure 22 is a diagram showing the procedure for changing the coverage status and updating the location of a terminal according to satellite movement.

[0029] Figure 23 is a diagram showing a discontinuous coverage scenario of a satellite communication network and the operation procedure of HLNR to respond to it.

[0030] Figure 24 is a diagram showing the overall structure of the HLNR.

[0031] Figure 25 is a block diagram showing the internal architecture of HLNR and detailed data flow between modules.

[0032] FIG. 26 is a system configuration diagram showing a communication path setup using a Regenerative Payload and an Xn interface-based ISL.

[0033] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0034] In the various embodiments of the present disclosure described below, a hardware-based approach is described as an example. However, since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0035] Terms used in the following description to refer to signals (e.g., signal, information, message, signaling), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), occasion), terms for operation states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to channels, terms referring to network entities, terms referring to device components, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0036] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0037] Additionally, in this disclosure, expressions of "greater than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled; however, this is merely for the purpose of expressing an example and does not exclude descriptions of "greater than" or "less than." Conditions described as "greater than" may be replaced with "greater than," conditions described as "less than" may be replaced with "less than," and conditions described as "greater than and less than" may be replaced with "greater than and less than." Furthermore, "A" to "B" below refer to at least one of elements from A (including A) to B (including B). Below, "C" and / or "D" refers to including at least one of "C" or "D," i.e., {'C', 'D', 'C' and 'D'}.

[0038] In the present disclosure, signal quality may be at least one of, for example, RSRP (reference signal received power), BRSRP (beam reference signal received power), RSRQ (reference signal received quality), RSSI (received signal strength indicator), SINR (signal to interference and noise ratio), CINR (carrier to interference and noise ratio), SNR (signal to noise ratio), EVM (error vector magnitude), BER (bit error rate), and BLER (block error rate). In addition to the examples described above, other terms having equivalent technical meanings or other metrics representing channel quality may be used. Hereinafter, in the present disclosure, high signal quality means a case where the signal quality value related to signal magnitude is large or the signal quality value related to error rate is small. Higher signal quality may mean that a smooth wireless communication environment is guaranteed. Furthermore, the optimal beam may mean the beam with the highest signal quality among the beams.

[0039] This disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), ETSI (European Telecommunications Standards Institute)), but this is merely illustrative. Various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0040] Users can utilize communication services using a terminal. A terminal is a device used by a user that can perform communication via a wireless channel. The terminal can connect to a network node that provides an access network. As technology advances, non-terrestrial networks utilizing satellites have been introduced as an effort to reduce dead zones. For example, a terminal located outside the coverage of a ground-based base station can access the Internet via the satellite. For satellite communication, various frequency bands (e.g., the Ku band of approximately 12–18 GHz, the Ka band of approximately 26.5 GHz–40 GHz, the V-band of approximately 40 GHz–75 GHz, and the E-band of approximately 60 GHz–95 GHz) are currently under discussion. However, frequency bands for satellite communication require additional modifications to terminals using cellular networks (or what may be referred to as mobile networks) or require the introduction of new communication equipment (e.g., hub devices). Currently, LTE (long term evolution) or 5G (5 th With terminals supporting cellular networks such as the generation being distributed in the market, modifying terminals or introducing new communication equipment to support satellite communication may be practically difficult in terms of workplace requirements and / or economic aspects. To resolve these difficulties, a communication service named DTC (direct to cell) (or may be referred to as D2C) has been introduced. Below, the communication environment for DTC is described through Figure 1.

[0041] Hereinafter, in order to explain the DTC according to the embodiments of the present disclosure, communication between a satellite and a ground-based communication device (e.g., a gateway) and communication between a satellite and a terminal may be distinguished. To provide DTC communication services, the frequency band used in communication between a satellite and a ground-based gateway may be referred to as the satellite frequency band. For example, the satellite frequency band may include the Ku-band (DL (downlink): 10.7 GHz (gigahertz) ~ 12.7 GHz, UL: 14.0 GHz ~ 14.5 GHz, FDD (frequency division duplex)). For example, the satellite frequency band may include the Ka-band (DL: 17.8 GHz ~ 20.2 GHz, UL: 27.5 GHz ~ 30.0 GHz, FDD). For example, the above satellite frequency band may also include the V-band (40GHz to 75GHz, time division duplex TDD). For example, the above satellite frequency band may also include the E-band (DL: 81GHz to 86GHz, UL: 71GHz to 76GHz, FDD). Frequency bands for Starlink Generation 2 satellites certified by the FCC include the Ku-band (DL: 10.7GHz to 12.7GHz, UL: 14.0GHz to 14.5GHz, FDD), the Ka-band (DL: 17.8GHz to 20.2GHz, UL: 27.5GHz to 30.0GHz, FDD), and the E-band (DL: 81GHz to 86GHz, UL: 71GHz to 76GHz, FDD).

[0042] To provide DTC communication services, the frequency band used for communication between a satellite and a terminal may be a frequency band of a cellular network (hereinafter referred to as a cellular frequency band). A cellular frequency band refers to a frequency band defined by a standardization body for mobile communication services. A DTC communication service may refer to a service in which a satellite provides an access network on a cellular frequency band rather than a frequency band for satellite communication. For example, the cellular frequency band may include a B2 band (or n2 band) (DL: 1930 MHz (megahertz) ~ 1990 MHz, UL: 1850 MHz ~ 1910 MHz, FDD (frequency division duplex)). For example, the cellular frequency band may include a B4 band (or n4 band) (DL: 2110 MHz ~ 2155 MHz, UL: 1710 MHz ~ 1755 MHz, FDD). For example, the cellular frequency band may include the B5 band (or n5 band) (DL: 869MHz ~ 894MHz, UL: 824MHz ~ 849MHz, FDD). For example, the cellular frequency band may include the B12 band (or n12 band) (DL: 729MHz ~ 746MHz, UL: 699MHz ~ 716MHz, FDD). For example, the cellular frequency band may include the B13 band (or n13 band) (DL: 746MHz ~ 756MHz, UL: 777MHz ~ 787MHz, FDD). For example, the cellular frequency band may include the B25 band (or n25 band) (DL: 1930MHz ~ 1995MHz, UL: 1850MHz ~ 1915MHz, FDD). For example, the cellular frequency band may include the B41 band (or n41 band) (2496 MHz to 2690 MHz, TDD).For example, the cellular frequency band may include the B55 band (or n55 band) (DL: 1432MHz to 1517MHz, UL: 1432MHz to 1517MHz, FDD). For example, the cellular frequency band may include the B71 band (or n71 band) (DL: 617MHz to 652MHz, UL: 663MHz to 698MHz, FDD). The frequency bands recently approved by the FCC for T-Mobile to provide DTC services via LEO satellites include the B2 band (DL: 1930MHz to 1990MHz, UL: 1850MHz to 1910MHz, FDD) and the B71 band (DL: 617MHz to 652MHz, UL: 663MHz to 698MHz, FDD).

[0043] FIG. 1 illustrates an example of a communication environment for DTC (direct to cell). DTC refers to a service in which communication between a satellite and a terminal is performed on a cellular frequency band rather than a satellite frequency band in a non-terrestrial network environment utilizing a satellite. The satellite may provide an access network to the terminal on the said cellular frequency band. Hereinafter, the term DTC is used to describe a cellular communication service provided by a satellite, but DTC may be referred to by technical terms other than DTC, such as direct-to-cellular, direct-to-cell satellites, and / or equivalent terms. Meanwhile, DTD (direct-to-device), which supports communication between two terminals via at least one satellite without passing through a node located on the ground on a cellular frequency band, can also be understood as a type of DTC.

[0044] Referring to FIG. 1, the communication environment may include a terminal (100), a satellite (110) for providing a non-terrestrial network, and / or a base station (134) for providing a terrestrial network. For example, the communication environment may include a terminal (101) and a terminal (103) as examples of the terminal (100). For example, the communication environment may include a satellite (110a), a satellite (110b), and / or a satellite (110c).

[0045] A terminal (100) is a device used by a user and communicates via a wireless channel with a base station (e.g., base station (134)) or a satellite (e.g., satellite (110)). A link from a base station or satellite toward the terminal (100) is referred to as a downlink (DL), and a link from the terminal (100) toward a base station or satellite is referred to as an uplink (UL). For example, the terminal (100) may include a cellular phone, a smartphone, a personal digital assistant (e.g., PDA), a laptop computer, a netbook, an e-reader, a wireless modem, etc. As an example, the terminal (100) may be referred to as a UE (user equipment) in 3GPP standards. However, since the scope of the embodiments in this disclosure is not limited to 3GPP standards, the terms "UE" and "terminal" may be used interchangeably in this specification to mean the more general term "wireless communication device." The terminal (100) may also be more generally referred to as a terminal device. As an example, but not limited to, the terminal (100) may be operated without user involvement. For example, the terminal (100) may be a device that performs machine type communication (MTC) and may not be carried by a user. Also, for example, the terminal (100) may be a narrowband (NB)-Internet of Things (IoT) device.

[0046] A base station (134) is a network infrastructure that provides wireless access to a terminal (100). A base station (134) may be referred to as a network entity located on the ground that provides an access network. For example, in 3GPP standards, a base station (134) may generally be referred to as an 'access point (AP)', 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning, in addition to 'node B', 'eBodeB (eNB)', '5G node (S5th generation node)', 'next generation nodeB (gNB)', and 'home enhanced or evolved node B (HeNB)'. Because the scope of the contents disclosed herein should not be limited to 3GPP standards, the terms “base station,” “node B,” “eNB,” and “HeNB” may be used interchangeably in this specification to mean the more general term “base station.” Additionally, the term “base station” may be used to denote an access point. An access point may be an electronic device that provides access to a network (e.g., a local area network (LAN), the Internet, etc.) for wireless communication devices. The term “communication device” may be used to denote both a wireless communication device and / or a base station. An eNB or gNB may also be referred to more generally as a base station device.

[0047] A satellite (110) may be a network entity for providing an access network. A satellite (110) represents a space-borne vehicle equipped with a communication transmitter, as a payload deployed in low-earth orbit (LEO), medium-earth orbit (MEO), or geostationary earth orbit (GEO). According to embodiments of the present disclosure, the satellite (110) may communicate with a terminal (100). The satellite (110) may provide an access network to the terminal (100). The access network may include one or more cells according to a frequency band (i.e., a cellular frequency band) according to a communication protocol (e.g., LTE (long-term evolution), 5G NR (new radio)) supported by the terminal (100). For example, the frequency band may be the LTE B25 band. For example, the frequency band may be the LTE B71 band. For example, the frequency band may be an LTE B2 band. The satellite (110) may communicate with the terminal (100) based on an access network. The satellite (110) may transmit signals over a cellular frequency band. A terminal (100) that supports the cellular frequency band may connect to a cell. The terminal (100) may transmit and receive signals over the cellular frequency band to the satellite (110). For example, the terminal (100) may communicate with the satellite (110a). The link between the terminal (100) and the satellite (110a) may be referred to as a service link. For example, the service link may include a first link (191a) representing forward downlink transmission and / or a second link (191b) representing reverse uplink transmission.

[0048] A satellite (110) can communicate with other satellites. The link between satellites may be referred to as an inter-satellite link (ISL). For example, satellite (110a) can communicate with satellite (110b) via an ISL (193ab). For example, satellite (110b) can communicate with satellite (110c) via an ISL (193bc). For example, satellite (110a) can communicate with satellite (110c) via an ISL (193ac). According to one embodiment, a satellite (110) can perform optical communication (e.g., laser communication) with other satellites. For example, laser communication using near-infrared light may be used for communication between satellites instead of using radio frequency (RF) bands. For example, satellite (110a) can transmit signals to satellite (110b) via a laser link using near-infrared light. By forming a network between satellites via the laser link, stable links can be formed even when the satellites move.

[0049] A satellite system operator (120) configured to provide a non-ground network via a satellite may be independent of a mobile network operator (MNO) (130) configured to provide a ground network. The communication infrastructure of the satellite system operator (120) may include not only the satellite (110), but also an earth ground station (EGS) (121) and a service network (125). For example, the earth ground station (121) may be understood as a gateway for communication with the satellite (110). For example, the satellite (110b) may communicate with the earth ground station (121). The satellite (110b) can communicate with the Earth ground station (121) over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). A link between the satellite (110b) and the Earth ground station (121) over the frequency band may be referred to as a feeder link. For example, the feeder link may include a third link (192a) representing a forward uplink transmission and / or a fourth link (192b) representing a reverse downlink transmission. The service network (125) may include a device (e.g., a server) that can be connected to the system of the satellite operator (120) and / or a communication network of the satellite operator (120) located on the ground. For reference, in FIG. 1, the service network (125) is labeled as a 'Satellite system Operator' in the sense that it oversees the satellite system, but this should be understood as referring to the same network entity or infrastructure as the 'service network' in this detailed description. Additionally, the service network (125) collectively refers to the core system, server, or management network operated by the satellite operator (120).Accordingly, in some drawings such as FIG. 1, the service network (125) may be described interchangeably with the name 'Satellite system Operator,' which is the subject of the system. Additionally, the service network (125) refers to the control and management infrastructure of the satellite operator (120), and is depicted as 'Satellite system Operator' in FIG. 1.

[0050] Additionally, the service network (125) may be understood to include or have the same configuration as a 'Constellation Management System' for managing and controlling the satellite's orbit, status, and ISL connection information. Accordingly, the operation of the Constellation Management System mentioned in the embodiments described below in this specification may be interpreted as being performed by the service network (125) or the server of the satellite operator (120). For example, through the service network (125), the Earth ground station (121) may be configured to connect the satellite (110b) with network entities deployed on the ground (e.g., communication equipment, location management devices of the mobile network operator (130). In FIG. 1, the Earth ground station (121) and the service network (125) are shown together as network entities of the satellite operator (120), but the embodiments of this disclosure are not limited thereto. Depending on the implementation example, the Earth ground station (121) of the satellite operator (120) may be directly connected to the network entity of the mobile network operator (130).

[0051] A satellite operator (120) connected to a satellite (110) may be required to be connected to a mobile network operator (130) in order to provide DTC communication services. The mobile network operator (130) may operate a system network (135). The system network (135) may include a device (e.g., a server) that can access the communication system of the mobile network operator (130) and / or a communication network of the satellite operator (120) located on the ground. The system network (135) of the mobile network operator (130) may be configured to provide an access network and / or a core network through a plurality of network entities. For example, the system network (135) may be an evolved packet system (EPS), and the plurality of network entities may include at least one of an evolved packet core (EPC)'s MME (mobility management entity), S-GW (serving gateway), P-GW (packet data network (PDN) gateway), data network (DN), and / or eNB. For example, the system network (135) is a 5GS (5G system), and the plurality of network entities may include at least one of the AMF (access and mobility management function), UPF (user plane function), SMF (session management function), data network, and / or gNB of the 5GC (5G core).

[0052] The Earth ground station (121) of the satellite operator (120) can be connected to at least one network entity (e.g., MME, S-GW, AMF, UPF, DN) among the plurality of network entities via a service network (125) on the ground. The base station (134) can be connected to at least one network entity (e.g., MME, S-GW, AMF, UPF) among the plurality of network entities. Internet access of the terminal (103) can be performed via a system network (135) designed by the mobile network operator (130). According to one embodiment, the system network (135) may include a data network. A terminal (e.g., terminal (101)) connected to the satellite (110a) can access the Internet via the data network. Communication can be performed with another terminal (e.g., terminal (103)) connected to the base station (134) via the Internet.

[0053] Satellite (110) (e.g., satellite (110a), satellite (110b), satellite (110c)) is a communication protocol of a cellular network (e.g., LTE, NR, 6G (6 thSignals according to the generation)) are transmitted, and the terminal (100) (e.g., terminal (101), terminal (102), terminal (103), terminal (104)) can receive and process the signals. Likewise, the terminal (100) transmits signals according to the communication standard of the cellular network (e.g., LTE), and the satellite (110) can receive and process the signals. The terminal (100) (e.g., terminal (101)) can transmit signals to the satellite (110) (e.g., satellite (110a)) located in the air, just as it transmits signals to a base station located on the ground (hereinafter, ground base station) (e.g., base station (134)). The satellite (110) can be configured to transmit signals on the cellular frequency band and receive signals received on the cellular frequency band in the same manner as the base station (134) located on the ground. The access network provided on the cellular frequency band may include one or more cells. The satellite (110) can transmit signals according to a communication protocol in a cellular frequency band. According to one embodiment, the satellite (110) may be connected to an Earth ground station (121) to obtain a configuration of a cell (hereinafter, cell configuration) to be provided as an access network, or may have information about a pre-configured cell configuration. According to another embodiment, the satellite (110) may be configured to convert signals received from the Earth ground station (121) into an RF domain and transmit the converted signals to a satellite or a terminal on the ground. The satellite (110) may support data transmission from a terminal (e.g., terminal (101)) to a terminal (e.g., terminal (103)). For example, the satellite (110a) may receive data from the terminal (101). However, the satellite (110a) cannot know whether the terminal (103) is connected to another satellite or to a cell of a base station located on the ground.In order to establish a session for transmitting data, it may be required that the satellite operator (120) for the satellite (110a) know location-related information of the terminal (103) (which may include physical location and / or connection information for establishing a communication path), or that the network operator connected to the terminal (103) (e.g., mobile network operator (130)) know location-related information of the terminal (101). However, since different operators, such as the satellite operator (120) and the mobile network operator (130), have independent network and operational policies, it may not be easy to configure a data transmission path in a unified manner. For example, since the satellite operator (120) does not provide independent cellular communication services, it may be difficult to access an already established cellular network environment. For example, because satellites are constantly moving along an orbit (e.g., LEO), it may be difficult for the mobile network operator (130) to manage the movement of all satellites and the cells provided by each satellite. Additionally, for example, when a terminal (103) is connected to a ground network, the satellite (110a) must transmit the received data to the terminal (103) via the data network of the mobile network operator (130). To do this, the satellite (110a) must connect directly to the Earth ground station (121) or connect to the Earth ground station (121) via an ISL (e.g., ISL (193ab)) with at least one satellite (e.g., satellite (110a), satellite (110b)). Such routing may be difficult to perform independently by the mobile network operator (130).

[0054] In the embodiments of the present disclosure below, a network entity connected to a satellite operator (120) and a mobile network operator (130) is described to configure a data transmission path for DTC communication services. The network entity may be configured to manage location-related information for each terminal connected to a terrestrial network and a terminal connected to a non-terrestrial network, acting as a location management server. The network entity may be referred to as a hybrid location network register (HLNR) in that it is connected to both terrestrial and non-terrestrial network (satellite network) operators (e.g., satellite operator (120), mobile network operator (130)) to relay the registration and management of terminal location information, and particularly plays a key role in interoperability between heterogeneous networks. Furthermore, embodiments for establishing a data transmission path based on location-related information stored in the network entity are described. FIGS. 2a and 2b describe a path setting environment between a satellite and an Earth ground station, and FIG. 3 describes an ISL, which is a link between satellites. In FIGS. 4 to 8b, the signal flow between each entity in the communication environment for DTC is described.

[0055] FIGS. 2a and FIGS. 2b illustrate examples of satellites moving along an orbit. For the satellites, the descriptions of the satellite (110) in FIG. 1 may be referenced.

[0056] Referring to FIG. 2a, a satellite operator (e.g., satellite operator (120)) may operate a number of satellites configured to orbit a planet (e.g., Earth) or a region of the planet. Each satellite may move along a designated orbit (e.g., first orbit (210), second orbit (220), third orbit (230), fourth orbit (240)). For example, along the first orbit (210), satellite (211), satellite (212), satellite (213), satellite (214), satellite (215), satellite (216), satellite (217), and / or satellite (218) may move. For example, along the second orbit (220), satellite (221), satellite (222), satellite (223), satellite (224), and / or satellite (225) may move. For example, along the third orbit (230), satellite (231), satellite (232), satellite (233), satellite (234), satellite (235), satellite (236), satellite (237), and / or satellite (238) may move. For example, along the fourth orbit (240), satellite (241), satellite (242), satellite (243), satellite (244), satellite (245), satellite (246), satellite (247), and / or satellite (248) may move.

[0057] Each satellite can move independently along a designated orbit (e.g., LEO, MEO, GEO). Meanwhile, a network entity connected to the satellite on the ground (e.g., Earth ground station (121)) can connect with one or more satellites. For example, when a satellite moving along an orbit enters the coverage of Earth ground station (121), the satellite may be connected to Earth ground station (121) via a feeder link. If the satellite is not within the coverage of Earth ground station (121), the satellite may be required to form an ISL link for DTC communication services. As another example, even if a satellite moving along an orbit enters the coverage of Earth ground station (121), the satellite may or may not be connected to Earth ground station (121) via a feeder link depending on whether additional conditions are met. If it is determined that additional conditions are not met, the satellite may be required to form an ISL link for DTC communication services.

[0058] Referring to FIG. 2b, the Earth ground station (121) and / or Earth ground station (251) may be located on the ground. Multiple satellites may be moving around the Earth ground station (121). Multiple satellites may be moving around the Earth ground station (251). For example, along one orbit, satellite (261), satellite (262), satellite (263), and / or satellite (264) may be moving. For example, along another one orbit, satellite (271), satellite (272), and / or satellite (273) may be moving. For example, along yet another one orbit, satellite (281), satellite (282), and / or satellite (283) may be moving. For example, along yet another one orbit, satellite (291), satellite (292), and / or satellite (293) may be moving.

[0059] A satellite entering the coverage area of ​​an Earth ground station (121) may be connected to the Earth ground station (121) via a feeder link. A satellite entering the coverage area of ​​an Earth ground station (251) may be connected to the Earth ground station (251) via a feeder link. According to one embodiment, when a satellite moving along an orbit simultaneously enters the coverage area of ​​a plurality of Earth ground stations, the satellite may be configured to select at least one Earth ground station to be connected among the plurality of Earth ground stations. This selection is intended to provide DTC communication services through the connection between the satellite and the Earth ground station. The selection of an Earth ground station by the satellite is described in detail through FIG. 11. According to one embodiment, when a plurality of satellites moving along an orbit simultaneously enter an Earth ground station, the Earth ground station may be configured to select at least one satellite to be connected among the plurality of satellites. Through this selection, a satellite for DTC communication services may be determined. The selection of a satellite by the Earth ground station is described in detail through FIG. 12.

[0060] FIG. 3 shows an example of a communication link between satellites. For the satellites, the descriptions of the satellite (110) in FIG. 1 may be referenced.

[0061] Referring to FIG. 3, satellites can move along an orbit. For example, satellite (311), satellite (312), and / or satellite (313) can move along a first orbit. For example, satellite (311) can communicate with a terminal (300) (e.g., DTC communication). The terminal (300) may be a smartphone of a user who has subscribed to a DTC communication service. For example, satellite (311) can communicate with terminal (301) (e.g., communication over the Ku band / Ka band). Terminal (301) may be communication equipment of a satellite operator (120) for providing satellite communication services. For example, satellite (312) can communicate with terminal (302) (e.g., DTC communication or Ku band / Ka band communication). For example, satellite (313) can communicate with terminal (303) (e.g., DTC communication or Ku band / Ka band communication). For example, satellite (321), satellite (322), and / or satellite (323) may move along a second orbit. For example, satellite (321) may communicate with terminal (304) (e.g., DTC communication or communication over the Ku band / Ka band). For example, satellite (322) may communicate with terminal (305) (e.g., DTC communication or Ku band / Ka band communication). For example, satellite (323) may communicate with terminal (306) (e.g., DTC communication or Ku band / Ka band communication).

[0062] A satellite (e.g., satellite (311)) located within the coverage (399) of the Earth ground station (121) can be connected to the Earth ground station (121). For example, the Earth ground station (121) and the satellite (311) can communicate over a satellite frequency band (e.g., Ka band, Ku band). A terminal (e.g., terminal (300)) connected to the satellite (311) can use DTC communication services through the satellite (311). Meanwhile, a satellite (e.g., satellite (323)) located outside the coverage (399) of the Earth ground station (121) can provide DTC communication services to a terminal (e.g., terminal (306)) connected to the satellite. For the DTC communication services, an ISL path may be configured. An ISL path may include one or more ISLs. ISLs may be classified into two types. Satellites moving along the same orbit (or orbits within an error range) may be referred to as a single satellite group. If the orbits of the two satellites are different (or orbits outside the error range), each satellite may belong to a different satellite group. For example, satellite (311), satellite (312), and / or satellite (313) may belong to the same satellite group. For example, satellite (321), satellite (322), and / or satellite (323) may belong to the same satellite group. For example, the satellite group of satellite (311) may be different from the satellite group of satellite (322).

[0063] ISL between satellites within the same satellite group may be referred to as In(intra)-plane ISL. In-plane ISL (IP ISL) refers to communication connections between satellites placed in the same orbital plane within an orbital satellite constellation (e.g., a constellation). For example, the ISL between satellite (311) and satellite (312) may be an In-plane ISL. For example, the ISL between satellite (312) and satellite (313) may be an In-plane ISL. For example, the ISL between satellite (321) and satellite (322) may be an In-plane ISL. For example, the ISL between satellite (322) and satellite (323) may be an In-plane ISL. The ISL between satellites belonging to different satellite groups may be referred to as Cross-plane ISL (CP ISL). That is, the above Cross-plane (CP) ISL represents a communication connection between satellites placed in different orbital planes within an orbital satellite constellation (e.g., a constellation). For example, the ISL between satellite (311) and satellite (322) may be a Cross-plane ISL. For example, the ISL between satellite (313) and satellite (322) may be a Cross-plane ISL. For example, the ISL between satellite (311) and satellite (321) may be a Cross-plane ISL. For example, the ISL between satellite (312) and satellite (321) may be a Cross-plane ISL. For example, the ISL between satellite (312) and satellite (321) may be an In-plane ISL. In the case of an In-plane ISL, optical communication (e.g., laser communication) and satellite tracking for the ISL may be easy because the position of the next satellite is predicted along a predefined orbit. In the case of a cross-plane ISL, not only is routing flexibility improved by using different orbital planes, but it can also be advantageous for optimizing the configuration of a path that includes at least one ISL depending on the location of the terminal.

[0064] FIG. 4 illustrates an example of a communication environment for communication scenarios using a satellite. The same reference numbers may be used for the same or similar descriptions.

[0065] Referring to FIG. 4, the communication environment (400) may include at least one terminal (e.g., terminal (101), terminal (102), terminal (103), and / or terminal (104)) and a satellite (e.g., satellite (111), satellite (112), satellite (113), and / or satellite (114)). For the terminal, the descriptions of the terminal (100) of FIG. 1 may be referenced. For the satellites, the descriptions of the satellite (110) of FIG. 1 may be referenced.

[0066] The communication environment (400) may include communication facilities of a satellite operator (120). The communication facilities of the satellite operator (120) may include a satellite (e.g., satellite (111), satellite (112), satellite (113), and / or satellite (114)), an earth ground station (121) for communication with said satellite, and a service network (125) for connection with a mobile network operator (130). For the earth ground station (121) and the service network (125), the descriptions of FIG. 1 may be referenced. The communication environment (400) may include communication facilities of a mobile network operator (130). The communication facilities of the mobile network operator (130) may include a system network (135). The system network (135) may include a plurality of network entities and a backhaul network for connections between network entities. For the system network (135), the descriptions of FIG. 1 may be referenced.

[0067] Satellites can be classified into various types depending on the role the satellite performs. In a communication environment (400), at least some of the satellites may be configured to provide DTC communication services. The DTC communication service refers to communication between a satellite and a terminal performed over a cellular frequency band. For example, a satellite (111) may provide one or more cells in a cellular frequency band to a terminal. For example, a satellite (111) may provide coverage (151) through one or more of the cells. The satellite (111) may be referred to as a service satellite (satellite #1 in FIG. 4). A terminal (e.g., terminal (101), terminal (104)) may be connected to the satellite (111) through the cells provided by the satellite (111). For example, a satellite (112) may provide one or more cells in a cellular frequency band to a terminal. For example, a satellite (112) may provide coverage (152) through one or more of the cells. The satellite (112) may be referred to as a service satellite (satellite #2 in FIG. 4). A terminal (e.g., terminal (101), terminal (104)) may be connected to the satellite (111) through the cells provided by the satellite (112). For example, the satellite (113) may be placed on the ground and may provide one or more cells of a cellular frequency band to the terminal. For example, the satellite (113) may provide coverage (153) through the one or more cells. The satellite (111) or the satellite (113) may be connected to an Earth ground station (121). A satellite connected to the Earth ground station (121) may be referred to as an access satellite. The satellite (111) may be both a service satellite and an access satellite. For example, the satellite (114) may serve as an intermediary to connect the satellite (111) and the satellite (112). The satellite (114) is connected to the satellite (111) via ISL, and the satellite (114) can be connected to the satellite (112) via ISL.The satellite (114) that acts as an intermediary can be referred to as a gateway satellite.

[0068] A satellite operator (120) configured to provide a non-terrestrial network via a satellite may be independent of a mobile network operator (130) configured to provide a terrestrial network. When a terminal attempts to transmit data to or receive data from another terminal, a connection between the two terminals may be required. Communication between the two terminals may be performed by accessing the Internet through the data network of the system network (135), or through at least one satellite (e.g., one satellite or two or more satellites) connected to the two terminals. Location-related information of each terminal may be required to define the data transmission path and connection method. A location management device (127) (e.g., HLNR) may be used as a network entity configured to manage location-related information of each terminal connected to a terrestrial network and a terminal connected to a non-terrestrial network. At this time, since the terrestrial network operator and the non-terrestrial network operator may use different network protocols and identification systems, a separate interface device is required for interoperability between heterogeneous networks. In the present invention, this role is performed by the HLNR (Hybrid Location Network Register), which integrates and manages the location information of the terminal in conjunction with both network operators and performs the function of mutual conversion and provision when necessary. The location management device (127) can be connected to each of the satellite operator (120) (e.g., service network (125)) and the mobile network operator (130) (e.g., system network (135)).

[0069] The location management device (127) may be referred to as a Hybrid Location Network Register (HLNR) and represents a database system that integrates and manages the location information of a terminal and the current serving network type in a hybrid network environment where non-terrestrial networks and terrestrial networks coexist, and provides mutual conversion between operators when necessary. The location management device (127) may be used to configure an optimal communication path for DTC communication services. Hereinafter, the location management device (127) is described as an entity independent of the service network (125) of the satellite operator (120) and the system network (135) of the mobile network operator (130). However, the embodiments of the present disclosure are not limited thereto. According to one embodiment, the location management device (127) may be included as a component within the Earth ground station and / or service network (125) of the satellite operator (120). As a non-limiting example, the Earth ground station (121) of the satellite operator (120) may be integrated with the service network (125). A satellite operator (120) may be connected to a system network (135) of a mobile network operator (130) via an HLNR (127). Alternatively, the HLNR (127) may be integrated within the system network (135) of the mobile network operator (130). The HLNR (127) may be operated by the satellite operator (120), the mobile network operator (130), or a third independent organization, and the satellite operator (120) and / or the mobile network operator (130) may request the location of a terminal connected to the satellite or base station from the HLNR (127), and the HLNR (127) may be configured to provide location information and connection network information of the terminal. An earth ground station (121) connected to the system network (135) may be configured to perform the functions of the location management device (127). A mobile network operator (130) may be configured to request the location of a terminal connected to the satellite from a satellite operator (120).According to another embodiment, the location management device (127) may be included as a component within the system network (135) of the mobile network operator (130). The satellite operator (120) may be configured to request the location of a terminal connected to the satellite from the mobile network operator (130). Alternatively, the HLNR (127) may be included as a component within the system network (135) of the mobile network operator (130). Even in this case, the satellite operator (120) may request and obtain location information of a terminal connected to the satellite through the HLNR (127).

[0070] Unlike the Home Location Register (HLR) / Home Subscriber Server (HSS) of existing mobile communication networks, the location management device (127) (e.g., HLNR) according to the embodiments of the present disclosure integrates and manages terminal location information of 3GPP networks and non-3GPP networks (satellite operators), and in particular, performs a key role for interoperability between heterogeneous networks by additionally managing network information of satellite operators. In particular, the location management device (127) performs a key role for interoperability between mobile communication operators and satellite operators by managing network information of satellite operators (e.g., satellite ID, orbit information, cell ID, beam coverage, frequency band, etc.). For example, a satellite operator (e.g., satellite operator (120)) can obtain the terminal's connected network type, location information, subscribed mobile carrier information, etc. through the location management device (127) to perform optimal satellite / beam selection, route setting, resource allocation, etc. A mobile communication operator (e.g., a mobile network operator (130)) can obtain location information of a terminal connected to a satellite network and network information of a satellite operator through a location management device (127) (e.g., HLNR) to perform billing, roaming, and guarantee service continuity. Without a location management device (127) (e.g., HLNR), it is difficult for the satellite operator and the mobile communication operator to determine the location information of a terminal connected to the other party's network in real time, which may lead to problems such as degraded service quality, inability to roam, and billing errors. Therefore, the location management device (127) (e.g., HLNR) according to the embodiments of the present disclosure acts as an essential component for providing smooth services between a mobile communication operator (e.g., a mobile network operator (130)) and a satellite operator (e.g., a satellite operator (120)) in a heterogeneous network environment.

[0071] Since the location management device (127) (e.g., HLNR) according to the embodiments of the present disclosure handles sensitive location information of multiple users, it is very important to maintain a high level of security. HLNR enhances security by ensuring that only authorized users / entities can access it through multi-factor authentication and role-based access control. HLNR encrypts both stored data and transmitted data to prevent data leakage and ensure integrity. HLNR responds to security threats by logging all access attempts and detecting and blocking abnormal access patterns. For example, HLNR applies the following security mechanisms. First, all users / entities attempting to access HLNR must undergo a strict authentication procedure including multi-factor authentication and biometric recognition. Second, authenticated users / entities are allowed to access, modify, or delete data only by predefined permissions through Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC). Third, all location and personally identifiable information stored in HLNR is encrypted using strong encryption algorithms such as AES-256 and TLS 1.3, and encrypted channels such as HTTPS and VPN are used during data transmission. Fourth, all access attempts to HLNR are recorded in log files, and abnormal access patterns are detected and blocked through regular audits and the use of Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS). Fifth, HLNR complies with relevant standard security specifications such as 3GPP TS 33.501 (5G Security Architecture and Procedures) and 3GPP TS 23.503 (5G Policy Framework), and maintains the security level of the system through regular security vulnerability checks and penetration testing.Sixth, in accordance with the personal data processing principles of the GDPR (General Data Protection Regulation), HLNR collects and retains only the minimum amount of data necessary to provide services, clearly defines the retention period for personal data, and securely deletes data upon expiration of the period. Finally, physical security measures, such as access control, CCTV installation, and fire / disaster preparedness systems, are applied to data centers where HLNR equipment is installed.

[0072] According to embodiments of the present disclosure, a location management device (127) (e.g., HLNR) performs functions that are differentiated from the HLR / HSS of existing mobile communication networks. Existing HLR / HSS primarily focused on managing subscriber information, service subscription status, and location information based on ground base stations. On the other hand, the location management device (127) of the present disclosure integrates and manages terminal location information of not only 3GPP-based ground networks but also non-3GPP-based satellite networks, and in particular, by managing network information of satellite operators, it plays a key role in interoperability between heterogeneous networks. In addition to the information managed by existing HLR / HSS, the location management device (127) additionally manages the following information for interoperability with satellite networks. For example, the location management device (127) may manage network information of a satellite operator including a satellite identifier (Satellite ID), orbit information (e.g., LEO, orbital inclination, altitude, period), cell identifier (Cell ID), beam coverage, frequency band (e.g., Ku-band, Ka-band, V-band, E-band), and / or satellite status information (e.g., operational status, resource availability rate, number of connected terminals). For example, the location management device (127) may manage location information of terminals connected to the satellite network including a satellite identifier, cell identifier, beam identifier, location coordinates (e.g., latitude, longitude, altitude), location accuracy, and / or positioning time. Since the location management device (127) handles sensitive location information, it is very important to maintain a high level of security. To this end, the location management device (127) may apply security mechanisms such as multi-factor authentication, role-based access control (RBAC), encryption such as AES-256, intrusion detection systems (IDS) and intrusion prevention systems (IPS), and GDPR compliance.

[0073] Specifically, the configuration and role of the location management device (127) (e.g., HLNR) according to the present disclosure may be as follows:

[0074] 1. Composition and Role of HLNR

[0075] According to embodiments of the present disclosure, a location management device (127) (e.g., HLNR) can perform functions that are differentiated from the Home Location Register (HLR) / Home Subscriber Server (HSS) of existing mobile communication networks. Existing HLR / HSS primarily focused on managing subscriber information, service subscription status, and location information based on ground base stations. On the other hand, the location management device (127) (e.g., HLNR) according to embodiments of the present disclosure integrates and manages terminal location information of non-3GPP-based satellite networks as well as 3GPP-based terrestrial networks, and in particular, by managing network information of satellite operators, it can play a key role in interoperability between heterogeneous networks. The HLNR may be operated by a satellite operator, a mobile communication operator, or a third independent organization.

[0076] 1.1 Additional Management Information for HLNR

[0077] A location management device (127) (e.g., HLNR) manages additional information such as the following for interoperability with a satellite network, in addition to the information managed by the existing HLR / HSS.

[0078] 1.1 Satellite Operator Network Information

[0079] * Satellite ID: Manages unique identifiers to identify individual satellites.

[0080] * Orbit Information: Manages detailed information related to the satellite's orbit, such as the satellite's orbit (e.g., LEO (Low Earth Orbit)), orbital inclination, altitude, and period.

[0081] * Cell ID: Manages unique identifiers to identify cells provided by the satellite.

[0082] * Beam Coverage: Manages information on the geographical area covered by a satellite's beam.

[0083] * Frequency Band: Manages the frequency bands used by satellites (e.g., Ku-band, Ka-band, V-band, E-band, etc.).

[0084] * Satellite Status Information: Manages information related to the satellite's operational status, such as the satellite's operational status (e.g., normal, faulty), resource availability rate, and the number of connected terminals.

[0085] 1.2 Location information of terminals connected to the satellite network

[0086] * Satellite ID: Manages the identifier of the satellite to which the terminal is connected.

[0087] * Cell ID: Manages the identifier of the cell to which the terminal is connected.

[0088] * Beam ID: Manages the identifier of the beam to which the terminal is connected.

[0089] * Location Coordinates: Manages the terminal's geographical location coordinates (latitude, longitude, altitude).

[0090] * Location Accuracy: Manages the accuracy of location information (e.g., margin of error).

[0091] * Positioning Time: Manages the time at which location information was measured.

[0092] 1.2 Interoperability Scenario Using HLNR

[0093] A location management device (127) (e.g., HLNR) serves as a gateway for information exchange and service interoperability between a satellite operator (e.g., satellite operator (120)) and a mobile communication operator (e.g., mobile network operator (130)). The following is an example of a specific interoperability scenario utilizing HLNR.

[0094] 1.2.1 Scenario 1: When a satellite operator detects a mobile carrier subscriber's connection and provides services

[0095] 1. User A, an SKT subscriber, uses a smartphone in a disaster area to send a rescue request signal.

[0096] 2. User A's smartphone attempts to connect to the nearest LEO (Low Earth Orbit) satellite (e.g., SpaceX's Starlink satellite).

[0097] 3. The Starlink satellite receives a service request message from User A's smartphone.

[0098] 4. The Starlink satellite sends a request message to HLNR to obtain location information, including user A's identification information (e.g., IMSI (International Mobile Subscriber Identity)).

[0099] 5. HLNR confirms that User A is an SKT subscriber based on IMSI and requests SKT’s HSS (Home Subscriber Server) to provide User A’s location information.

[0100] 6. SKT's HSS provides User A's latest location information (e.g., connected base station, cell ID, etc.) to HLNR.

[0101] 7. HLNR stores the location information of user A, the subscribed mobile carrier (SKT), and the network information of the Starlink satellite (e.g., satellite ID, orbit, cell ID, beam coverage).

[0102] 8. HLNR provides User A's location information and SKT subscriber information to the Starlink satellite.

[0103] 9. The Starlink satellite selects the optimal beam based on User A's location information and provides Direct-to-Cell (DTC) services to User A's smartphone.

[0104] 10. The Starlink satellite connects with the SKT network to transmit billing information regarding User A's service usage.

[0105] 11. SKT charges User A for the use of the DTC service.

[0106] 1.2.2 Scenario 2: When a mobile carrier provides roaming services to a subscriber connected to a satellite network

[0107] 1. User B, a KT subscriber, applies for KT roaming service while traveling abroad.

[0108] 2. User B enters an area where communication with a ground base station at the travel destination is impossible and connects to an LEO satellite (e.g., OneWeb satellite).

[0109] 3. The OneWeb satellite sends a request message to HLNR to obtain location information, including user B's identification information (e.g., IMSI).

[0110] 4. HLNR confirms that User B is a KT subscriber based on IMSI and requests KT’s HSS to provide User B’s roaming service subscription status and location information.

[0111] 5. KT’s HSS confirms that User B is subscribed to the roaming service and provides User B’s latest location information (e.g., connected base station, cell ID, etc.) along with a roaming service permission response to the HLNR.

[0112] 6. HLNR stores user B's roaming service subscription information, location information, KT subscriber information, and OneWeb satellite network information in association.

[0113] 7. HLNR provides the OneWeb satellite with User B's roaming service permission status, location information, and KT subscriber information.

[0114] 8. OneWeb satellite provides roaming services to User B.

[0115] 9. The OneWeb satellite is linked with the KT network to transmit billing information regarding User B's use of the roaming service.

[0116] 10. KT charges User B for the use of the roaming service.

[0117] 1.2.3 Scenario 3: Emergency rescue request via satellite network in a disaster situation

[0118] 1. User C (LG U+ subscriber) gets lost while hiking and requests emergency rescue.

[0119] 2. Since User C's smartphone is unable to communicate with the ground base station, it attempts to connect to the nearest LEO satellite (e.g., Amazon's Kuiper satellite).

[0120] 3. The Kuiper satellite receives an emergency rescue request message from user C's smartphone.

[0121] 4. The Kuiper satellite sends a location information acquisition request message to HLNR, including the identification information (e.g., IMSI) of user C.

[0122] 5. HLNR confirms that User C is an LG U+ subscriber based on IMSI and requests LG U+’s HSS to provide User C’s location information.

[0123] 6. LG U+’s HSS provides User C’s latest location information (e.g., connected base station, cell ID, etc.) and subscriber information to HLNR.

[0124] 7. HLNR stores the location information of user C, the subscribed mobile carrier (LG U+), and the network information of the Kuiper satellite in association.

[0125] 8. HLNR provides User C's location information and LG U+ subscriber information to the Kuiper satellite.

[0126] 9. The Kuiper satellite transmits an emergency rescue request message to the nearest rescue agency based on the location information of user C.

[0127] 10. The Kuiper satellite links with the LG U+ network to notify User C of the fact of an emergency rescue request.

[0128] 11. LG U+ notifies User C's family of the emergency situation. 12. The HLNR can also establish a direct communication channel with the terminal (101) to request additional information related to the emergency rescue from User C (e.g., injury status, surrounding environment) or to notify the progress of the rescue. Such direct communication between the HLNR and the terminal can be particularly useful in disaster situations where communication via terrestrial networks and satellites is difficult.

[0129] 12. HLNR can support rapid rescue by transmitting emergency situations to other nearby terminals (e.g., volunteers, rescue workers) based on the location information of user C through cooperation with satellite operators.

[0130] In the above example, the HLNR establishes a direct communication channel with the terminal (101) in the disaster area to request additional information related to emergency rescue from user C (e.g., injury status, surrounding environment) or to notify the progress of the rescue. Such direct communication between the HLNR and the terminal can be particularly useful in disaster situations where communication via ground networks and satellites is difficult.

[0131] 1.3 Problems in the Absence of HLNR

[0132] In the above scenario, if there is no location management device (127) (e.g., HLNR), it is difficult for satellite operators and mobile carriers to share user information in real time. This leads to problems such as degraded service quality, inability to roam, billing errors, and inefficient resource management. For example, satellite operators find it difficult to provide appropriate DTC / DTD services because they cannot determine which mobile carrier a user is subscribed to or which rate plan they are using. Additionally, mobile carriers find it difficult to respond quickly in the event of an emergency because they cannot accurately determine the location of subscribers connected to the satellite network.

[0133] 1.4 Location management device (127) (e.g., HLNR) security mechanism

[0134] Since the location management device (127) of the present disclosure (e.g., HLNR) handles sensitive location information of multiple users, it is very important to maintain a high level of security. To this end, the HLNR applies the following security mechanisms.

[0135] 1.4.1 Authentication and Authorization

[0136] All users / entities attempting to access HLNR must undergo strict authentication procedures such as Multi-factor Authentication, biometric authentication, OAuth 2.0, and SAML (Security Assertion Markup Language).

[0137] Authenticated users / entities can access, modify, or delete data only according to predefined permissions through Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC). For example, a satellite operator may be granted permission to view only the location information of a specific user, and a mobile telecommunications operator may be granted permission to modify only billing-related information.

[0138] 1.4.2 Data Encryption

[0139] All location information and personally identifiable information (PII) stored in HLNR is encrypted using strong encryption algorithms such as AES-256 (Advanced Encryption Standard 256-bit) and TLS 1.3 (Transport Layer Security 1.3).

[0140] Encrypted channels such as HTTPS (Hypertext Transfer Protocol Secure) and VPN (Virtual Private Network) are also used during data transmission.

[0141] 1.4.3 Access Control and Audit Logging

[0142] All access attempts to HLNR are recorded in the log file, and regular audits are performed.

[0143] Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) are utilized to detect and block abnormal access patterns (e.g., frequent access attempts from specific IPs, attempts to access unauthorized data).

[0144] 1.4.4 Security Protocol and Standard Compliance

[0145] HLNR complies with security standards established by relevant standards organizations, such as 3GPP TS 33.501 (5G security architecture and procedures), 3GPP TS 23.503 (5G policy framework), GSMA FS.19 (IoT SAFF 1.0), and ETSI EN 303 645 (cybersecurity; cybersecurity for the Consumer Internet of Things).

[0146] Maintain the system's security level by performing regular security vulnerability checks and penetration tests.

[0147] 1.4.5 Data Minimization and Retention Limitation

[0148] HLNR collects and retains only the minimum amount of data necessary to provide services, in accordance with the personal data processing principles of the GDPR (General Data Protection Regulation).

[0149] Clearly define the retention period for personal information and securely delete data upon expiration.

[0150] 1.4.6 Physical Security

[0151] Data centers equipped with HLNR equipment are subject to physical security measures such as access control, CCTV installation, and fire / disaster preparedness systems.

[0152] 1.5 HLNR Redundancy / Multiplication Configuration

[0153] Since HLNR is a system that performs a critical role, redundancy or multiplexing configurations may be applied to prevent service interruption in the event of a failure. For example, various redundancy / multiplexing methods such as Active-Standby, Active-Active, N+1, and N+M redundancy can be applied.

[0154] In an Active-Standby configuration, if the primary HLNR device fails, the standby HLNR device is immediately activated to continue providing services. In an Active-Active configuration, multiple HLNR devices operate simultaneously, distributing traffic through load balancing, and another device immediately provides services in the event of a failure.

[0155] Redundancy / multiplex configuration increases the availability of HLNR and minimizes service downtime, ensuring stable service provision.

[0156] 1.6 Interoperability Plan between HLNR and 5GC

[0157] The HLNR of the present invention is coupled with the 5GC (5G Core Network) in a 5G network environment to support integrated subscriber management and service provision between terrestrial and satellite networks. In particular, the HLNR can be coupled with the AUSF (Authentication Server Function) and UDM (Unified Data Management) within the 5GC.

[0158] AUSF is a network function (NF) of the 5GC responsible for subscriber authentication, and UDM is a network function (NF) of the 5GC that manages subscriber data, service data, etc. HLNR performs authentication of terminals connecting to the satellite network through interoperability with AUSF, and can obtain subscriber information, location information, service profiles, etc. through interoperability with UDM.

[0159] For example, when a terminal attempts to connect to a satellite network, the satellite requests authentication of the terminal from the AUSF via HLNR. The AUSF performs terminal authentication based on subscriber information stored in the UDM and transmits the result to the satellite via HLNR. If authentication is successful, the satellite obtains the terminal's location information, service profile, etc. from the UDM via HLNR and can provide a suitable service to the terminal.

[0160] In addition, HLNR can be linked with the Access and Mobility Management Function (AMF), Session Management Function (SMF), and Policy Control Function (PCF) within the 5GC to support mobility management, session management, and Quality of Service (QoS) control of the terminal.

[0161] Through this interoperability between HLNR and 5GC, seamless service provision between terrestrial and satellite networks becomes possible in a 5G network environment.

[0162] As described above, the HLNR according to the embodiments of the present disclosure integrates and manages terminal location information of 3GPP and non-3GPP networks and additionally manages network information of satellite operators, thereby playing a key role in facilitating seamless service interoperability between mobile operators and satellite operators in a heterogeneous network environment. In addition, the HLNR can ensure the confidentiality, integrity, and availability of sensitive location information by applying strict security mechanisms.

[0163] According to one embodiment, in a first communication scenario, a terminal (101) can communicate with a terminal (103). The terminal (101) may be located within the coverage of a satellite (111) that provides a non-ground network. The terminal (103) may be located within the coverage of a ground network base station (134). The terminal (101) may access a data network through the satellite (111), the Earth ground station (121), the service network (125), and the system network (135). The terminal (103) may access a data network through the base station (134) and the backhaul network (132). In the first communication scenario, operations for establishing a data transmission path between the terminal (101) and the terminal (103) upon the request of the terminal (101) are described in detail through FIGS. 5A and 5B.

[0164] According to one embodiment, in a second communication scenario, a terminal (103) can communicate with a terminal (101). The terminal (101) may be located within the coverage of a satellite (111) that provides a non-ground network. The terminal (103) may be located within the coverage of a ground network base station (134). In the second communication scenario, operations for establishing a data transmission path between the terminal (101) and the terminal (103) at the request of the terminal (103) are described in detail through FIGS. 6a and 6b.

[0165] According to one embodiment, in a third communication scenario, a terminal (101) can communicate with a terminal (104). The terminal (101) may be located within the coverage of a satellite (111). The terminal (104) may be located within the coverage of a satellite (111). The terminal (101) may be connected to the terminal (104) via the satellite (111). Communication between the terminal (101) and the terminal (104) can be understood as DTD communication because data is transmitted via the satellite (111) without passing through a path of a ground network. In the third communication scenario, operations for establishing a data transmission path between the terminal (101) and the terminal (104) at the request of the terminal (101) are described in detail through FIG. 7.

[0166] According to one embodiment, in a fourth communication scenario, a terminal (101) can communicate with a terminal (102). The terminal (101) may be located within the coverage of a satellite (111). The terminal (102) may be located within the coverage of a satellite (112). The terminal (101) may be connected to the terminal (102) through the satellite (111), the satellite (114), and the satellite (112). Since data between the terminal (101) and the terminal (102) is transmitted through the satellite (111), the satellite (114), and the satellite (112) without passing through a path of a ground network, it can be understood as DTD communication. In the fourth communication scenario, operations for establishing a data transmission path between the terminal (101) and the terminal (102) upon the request of the terminal (101) are described in detail through FIGS. 8A and FIGS. 8B.

[0167] In this disclosure, various messages are defined to describe signaling between components in a communication environment using a satellite (e.g., the communication environment of FIG. 1, communication environment (400)). Each of the messages described below may have a predefined format. Hereinafter, the format of the message is used as an example to describe the embodiment and is not to be interpreted as limiting other embodiments of this disclosure by a specific format.

[0168] Hereinafter, in the present disclosure, the types for describing each data type are as follows.

[0169] - uint8: 8-bit unsigned integer (0-255)

[0170] - uint16: 16-bit unsigned integer (0-65535)

[0171] - uint32: 32-bit unsigned integer

[0172] - String: UTF-8 encoded string

[0173] - Binary: Binary data

[0174] - Enum: Enumerated data

[0175] - Structure: Complex data structure

[0176] - Array: An array of data of the same type

[0177] The symbols "-" and "--" used within the structure of a message information element according to an embodiment of the present disclosure are notations indicating the hierarchy of the data structure included within the message information element. "-" represents lower level 1, and "--" represents lower level 2. For example, if the structure of the QoS (quality of service) status information (e.g., 'QoS Status' IE) within the service activation message [Table 12] described below is expressed in a tree form, it is as shown in [Table 1] below.

[0178]

[0179] FIGS. 5a and 5b illustrate examples of signaling of network entities in a first communication scenario using a satellite. Identical reference numbers may be used for identical or similar descriptions. In the first communication scenario, an example of configuring a data transmission path including a satellite is described in the procedure in which a terminal (101) transmits data to a terminal (103). In embodiments of the present disclosure, direct message transmission between subscribers of different TN network operators (e.g., between a T-mobile subscriber and a Verizon subscriber) may be difficult, but indirect message transmission may be supported by determining the location information of the other party through a location management device (127) (e.g., HLNR) and establishing an optimal communication path (e.g., via a terrestrial network) based thereon.

[0180] Referring to FIGS. 5a and 5b, in operation (S501), the terminal (101) may transmit a service request to the satellite (111). The service request may be used to initiate a DTC communication service for data transmission between the terminal (101) and the terminal (103). According to one embodiment, the service request may include identification information of the terminal (103) (e.g., ID of the terminal (103)). The terminal (101) may transmit the service request to the satellite (111) via a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). For example, the service request may be an uplink message (e.g., PUSCH) on an LTE or NR standard. For example, if a call service is to be performed via DTC, the service request may correspond to a SIP (session initiation protocol) INVITE message. The service request may have the following format.

[0181]

[0182] In operation (S502), a location management device (127) (e.g., HLNR) may obtain location-related information (e.g., location, network) of at least one terminal (e.g., terminal (103)) located on a terrestrial network through the system network (135) of a mobile network operator (130). According to embodiments of the present disclosure, the location-related information may include identification information of the terminal, location of the terminal, network status connected to the terminal (e.g., connection availability, amount of available resources, number of connected terminals), and / or network type of the cell to which the terminal is connected (e.g., whether it is a terrestrial network, network ID (identity), whether it is a non-terrestrial network, connected satellite ID, and / or satellite group ID to which the connected satellite belongs, and operator network ID to which the terminal is connected (e.g., PLMN ID)). The location management device (127) may include a database configured to manage location-related information per terminal. The location management device (127) may be configured to manage location-related information for terminals (e.g., terminal (103)) connected to a base station of a ground network (e.g., base station (134)) as well as terminals (e.g., terminal (101), terminal (102), and / or terminal (104)) connected to a satellite of a non-ground network (e.g., satellite (110)) in a hybrid network environment where a non-ground network and a ground network coexist.

[0183] According to one embodiment, the location management device (127) may obtain location-related information of a terminal from an external device (e.g., a server of a satellite operator (120), a server of a mobile network operator (130). The location management device (127) may obtain location-related information of various terminals periodically or upon request. The location management device (127) may store the obtained location-related information for each terminal in a table. The table may store a list of terminals and location-related information of each terminal as data. The location management device (127) may be configured to update the table whenever it obtains information regarding the location of a terminal. For example, registering the location-related information of a terminal to the location management device (127) by an external device may include the external device transmitting a registration request message having the following format to the location management device (127).

[0184]

[0185] According to embodiments of the present disclosure, a location management device (127) may be configured to register location-related information of a terminal. The location management device (127) may receive location-related information of a terminal from a server of a satellite operator (120) (e.g., a ground station (121)) or a server of a mobile network operator (130) (e.g., a network entity of a system network (135)). The location management device (127) may be configured to store location-related information of a terminal in a table (e.g., a location-network table). The location management device (127) may be connected to different operators (e.g., the satellite operator (120) and the mobile network operator (130) may be different operators). Accordingly, the location management device (127) may be configured to manage a synchronized data format for requests from different operators.

[0186] In FIG. 5a, the operation (S502) is depicted as being described after the operation (S501), but embodiments of the present disclosure are not limited thereto. The operation (S502) may be performed periodically and may be performed before the operation (S501).

[0187] In operation (S503), the satellite (111) may transmit an inquiry message to the satellite (113) to request location-related information of the terminal (103). The satellite (111) may obtain information about the terminal (103) (e.g., ID of the terminal (103)) from the service request of the terminal (101). The satellite (111) may transmit the inquiry message containing information about the terminal (103) (e.g., ID of the terminal (103)) to the satellite (113). The satellite (113) may be referred to as an access satellite as a satellite connected to the Earth ground station (121). In order to obtain information about the location and network type of the counterpart terminal, the satellite (111) is required to be connected to a location management device (127) located on the ground. The satellite (111) may transmit the inquiry message to the satellite (113) which is capable of connecting to the location management device (127). According to one embodiment, the satellite (111) can transmit the inquiry message to the satellite (113) via optical communication. For example, the inquiry message may have the following format.

[0188]

[0189] In operation (S504), the satellite (113) may transmit an inquiry message to the Earth ground station (121) to request location-related information of the terminal (103). The inquiry message may correspond to the inquiry message of operation (S503). The inquiry message may include identification information of the terminal (103) (e.g., ID of the terminal (103)). According to one embodiment, the satellite (113) may transmit the inquiry message to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0190] In operation (S506), the Earth ground station (121) may send an inquiry message to the location management device (127) to request location-related information of the terminal (103). The inquiry message may correspond to the inquiry message of operation (S504). The inquiry message may include identification information of the terminal (103) (e.g., ID of the terminal (103)). The Earth ground station (121) may connect to the location management device (127) through the service network (125) of the satellite operator (120). The Earth ground station (121) may send the inquiry message to the location management device (127) through the service network (125).

[0191] In operation (S508), the location management device (127) may transmit a response message containing location-related information corresponding to the terminal (103) to the earth ground station (121). When the location management device (127) receives an inquiry message from the earth ground station (121), it may obtain identification information of the terminal (103) included in the inquiry message. The location management device (127) may identify data associated with the identification information of the terminal (103) within a database. The data may include information regarding the location data of the terminal (103), the network status of the terminal (103) (e.g., availability of resources, available bandwidth, number of connected terminals, base station ID, cell ID, PLMN (public land mobile network) ID), etc.), and / or the network type of the terminal (103) (e.g., whether it is a terrestrial network or a non-terrestrial network). The inquiry message may respond to a request for location-related information corresponding to the terminal (103). The location management device (127) may, in response to the request, transmit a response message containing data associated with the terminal (103) stored in the database to the Earth ground station (121). The location management device (127) may transmit the response message to the Earth ground station (121) via the service network (125). As an example not limited to, the location management device (127) may convert data containing location-related information of the terminal (103). The format of the data stored in the table may differ from the format used by the operator that transmitted the inquiry message (i.e., the operator of the node). The location management device (127) may convert the data into a format corresponding to the operator that transmitted the inquiry message (i.e., the operator of the node). The location management device (127) may transmit a response message containing the converted data.

[0192] For example, the above response message may have the format of the table below. The above response message may have a format determined according to the instructions in the above inquiry message.

[0193] [Table 4-1]

[0194]

[0195] In operation (S510), the Earth ground station (121) may transmit a response message containing location-related information of the terminal (103) to the satellite (113). The response message may correspond to the response message of operation (S508). The Earth ground station (121) may transmit the response message to the satellite (113), which is an access satellite. According to one embodiment, the Earth ground station (121) may transmit the response message to the satellite (113) through a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0196] In operation (S512), the satellite (113) may transmit a response message containing location-related information of the terminal (103) to the satellite (111). The response message may correspond to the response messages of operation (S508) and operation (S510). According to one embodiment, the satellite (113) may transmit the response message to the satellite (111) via optical communication.

[0197] In operation (S514), the satellite (111) can determine a data transmission path. The satellite (111) can determine the data transmission path based on location-related information of the terminal (103). The data transmission path may include a satellite (e.g., satellite (111)) that provides DTC services and may represent a signal transmission path from a source terminal (e.g., terminal (101)) to a destination terminal (e.g., terminal (103)). For example, the satellite (111) can obtain the location of the terminal (101) that is connected to the cell of the satellite (111). The satellite (111) can obtain location-related information of the terminal (103) (e.g., location of the terminal (103), network status of the terminal (103), network type, other connection information) through the response message of operation (S512). The satellite (111) can configure a data transmission path based on information regarding the location of the terminal (101), the location of the terminal (103), and / or the network to which the terminal (103) is connected. For example, since the terminal (103) is connected to a ground network, the satellite (111) can determine a data transmission path that includes a satellite (e.g., satellite (113)) that is connectable to an earth ground station (e.g., earth ground station (121)), at least some paths of the service network (125) of the satellite operator (120), and at least some paths of the system network (135) of the mobile network operator (130).

[0198] As a non-limiting example, if the satellite (111) can directly connect to an Earth ground station (e.g., Earth ground station (121)), the satellite (111) may not include the satellite (113) in the data transmission path. This is because the satellite (111) functions as an access satellite as well as a service satellite. If the satellite (111) functions as an access satellite, there is no need to configure a separate ISL path. However, if the satellite (111) is required to be connected to another satellite (e.g., the satellite (113) corresponding to the access satellite), at least one ISL may be required.

[0199] In operation (S516), the satellite (111) can identify an ISL path. The satellite (111) can identify an ISL path of a data transmission path for connection with the satellite (113). The ISL path may include at least one ISL. According to one embodiment, the satellite (111) can determine a starting position (or source satellite) and a destination position (or destination satellite). For example, the satellite (111) may use identification information of the satellite (111) and location information of the satellite (111) as the starting position. For example, the satellite (111) may use identification information of the satellite (113) and location information of the satellite (113) as the destination position. According to one embodiment, the satellite (111) may use various parameters to determine the ISL path. The satellite (111) may use at least one of various parameters to determine an ISL path between satellites. For example, the various parameters mentioned above may include a maximum number of hops (i.e., the number of allowed transits). The satellite (111) may determine a data transmission path that includes at least one ISL that does not exceed the maximum number of hops. For example, the various parameters may include reference conditions (e.g., delay, bandwidth, reliability). The satellite (111) may determine a data transmission path optimized according to the reference conditions among a number of candidate paths. For example, the various parameters may include information regarding path constraints (e.g., ISL path indication limited to bitmaps, cross-plane ISL is restricted). The satellite (111) may determine a data transmission path that satisfies the path constraints among a number of candidate paths.

[0200] A satellite (111) can identify an ISL path of a data transmission path for a connection between the satellite (111) and the satellite (113). The ISL path may include at least one ISL. For example, the satellite (111) can identify a first ISL between the satellite (111) and the satellite (114) and a second ISL between the satellite (114) and the satellite (113).

[0201] In operation (S518), the satellite (111) can perform path setting. The satellite (111) can set a data transmission path including an ISL path in a satellite network environment where multiple satellites are clustered. The ISL path may be defined by at least one ISL, each formed between at least one satellite and / or two satellites. The satellite (111) can generate path information representing the data transmission path. For example, the satellite (111) can generate path information configured in a format such as {ISL #1: ID of satellite (111), ID of satellite (114), ISL #2: ID of satellite (114), ID of satellite (113)}. For example, the path information may have the following format.

[0202]

[0203] According to one embodiment, the route information may be used for a service connection procedure. The service connection procedure may include a resource verification procedure based on a request from a source terminal (e.g., terminal (101)) and an authentication procedure based on a response from a destination terminal (e.g., terminal (101)). As an example, but not limited to, the route information may be transmitted together with data during data transmission via ISL between satellites.

[0204] In operation (S520), the satellite (111) may transmit a forward request to the satellite (114). The forward request may be used to determine whether service provision is possible (e.g., whether the terminal is located within coverage, whether available resources are available) in the network of the recipient (e.g., terminal (103)) for communication. The satellite (111) may transmit the forward request to the satellite (114) based on the path information. The satellite (114) may be referred to as a gateway satellite as an intermediary used to form an ISL path between two satellites. According to one embodiment, the satellite (111) may transmit the forward request to the satellite (114) via optical communication. For example, the forward request may have the following format.

[0205]

[0206] In operation (S522), the satellite (114) can transmit a transmission request to the satellite (113). The satellite (114) can transmit the transmission request to the satellite (113) based on the path information. According to one embodiment, the satellite (114) can transmit the transmission request to the satellite (113) via optical communication.

[0207] In operation (S524), the satellite (113) can transmit a transmission request to the Earth ground station (121). The satellite (113) can transmit the transmission request to the Earth ground station (121) based on the path information. According to one embodiment, the satellite (113) can transmit the transmission request to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0208] In operation (S526), ​​the Earth ground station (121) can transmit a transmission request to the base station (134). The Earth ground station (121) can transmit the transmission request to the base station (134) based on the path information. The Earth ground station (121) can transmit the transmission request to the base station (134) through the network path of the service network (125) of the satellite operator (120) and the network path of the system network (135) of the mobile network operator (130).

[0209] In operation (S528), the base station (134) can check coverage and / or resources. The base station (134) can determine whether the terminal (103) is located on the coverage of the cell provided by the base station (134). The base station (134) can determine whether there are available resources on the cell. If the terminal (103) is located on the coverage of the cell and there are available resources on the cell, the base station (134) can perform an authentication procedure with the terminal (103). The authentication procedure is described through FIG. 5b. Although not shown in FIG. 5a and FIG. 5b, the base station (134) may attempt to reallocate resources or transmit an error response to the delivery request if the terminal (103) is not located on the coverage of the cell or if there are no available resources for the terminal (103) on the cell. As a non-limiting example, checking the coverage may include identification information IDs of areas indicating service coverage (e.g., cell ID, area ID, tracking area identity (TAI)), location information of said area (e.g., coordinate data), and / or status information of said area (e.g., fully available, partially available, unavailable). As a non-limiting example, checking the resource status may include checking available resources as well as checking additional resource parameters. said resource parameters may include resource type (e.g., bandwidth, power, time slot), information on the amount of resources required, and / or information on the amount of resources available. Path setting may fail depending on an error response. In such cases, upon receiving the error response, the satellite (111) may search for an alternative path.

[0210] In operation (S530), the base station (134) can transmit a notification message to the terminal (103). The base station (134) can transmit the notification message to the terminal (103) on the cell of the base station (134). The notification message may be a signal according to a corresponding communication protocol (e.g., LTE, NR standard) on the band of a cellular network. Based on the notification message, the terminal (103) can establish a connection with the base station (134). For example, the notification message may have a format such as the table below.

[0211]

[0212] As a non-limiting example, the connection state of the terminal (103) may change to the RRC CONNECTED state upon receiving the notification message while in the RRC (radio resource control) IDLE state. For example, in terms of the change in the connection state, the notification message may be referred to as a paging message. The terminal (103) may be configured to monitor the notification message according to the period of the notification message (e.g., 'Interval' IE).

[0213] In operation (S532), the base station (134) may transmit an authentication request message to the terminal (103). The authentication request message may include an inquiry to the terminal (103) regarding whether to allow data transmission with the terminal (101). For example, the authentication request message may include identification information of the terminal (101). For example, the authentication request message may include information related to the authentication of the terminal (101). As an example, the information related to the authentication of the terminal (101) may have the following format.

[0214]

[0215] In operation (S534), the terminal (103) may transmit an authentication response message to the base station (134). The authentication response message may indicate that the terminal (103) allows data transmission from the terminal (101). For example, the authentication response message may correspond to the authentication request message. As an example, the authentication response message may have the following format.

[0216]

[0217] In operation (S536), the base station (134) can transmit an authentication response message to the Earth ground station (121). The authentication response message may correspond to the response message of operation (S534). The base station (134) can transmit the authentication response message to the Earth ground station (121) through the service network (125) of the satellite operator (120) and the system network (135) of the mobile network operator (130).

[0218] In operation (S538), the Earth ground station (121) may transmit an authentication response message to the satellite (113). The authentication response message may correspond to the response message of operation (S534) and / or operation (S536). According to one embodiment, the Earth ground station (121) may transmit the authentication response message to the satellite (113) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0219] In operation (S540), the satellite (113) may transmit an authentication response message to the satellite (111). The authentication response message may correspond to the response message of operation (S534), operation (S536), and / or operation (S538). According to one embodiment, the satellite (113) may transmit the authentication response message to the satellite (111) via optical communication.

[0220] In operation (S542), the satellite (111) can check coverage and / or resources. The satellite (111) can determine whether the terminal (101) is located on the coverage of the cell provided by the satellite (111). The satellite (111) can check the availability of resources. The satellite (111) can obtain information about resources predefined for the cell. The predefined resources may be predefined for the satellite (111)'s DTC communication service. According to one embodiment, the predefined resources may be preconfigured within the satellite (111) before the terminal (101) connects. According to another embodiment, they may be obtained by a separate procedure performed in response to a service request from the terminal (101) (e.g., the satellite (111) requests cellular network resources from the satellite operator (120) or the mobile network operator (130). For example, the aforementioned predefined resources may represent time-frequency resources on an LTE communication system or a resource grid of an LTE communication system. If a terminal (101) is located in the coverage of the cell and there are available resources on the cell, the satellite (111) may perform an operation (S544). Although not illustrated in FIGS. 5a and 5b, if the terminal (101) is not located in the coverage of the cell or there are no available resources on the cell, the satellite (111) may transmit a rejection response to the service request of the operation (S501) to the terminal (101). As an example, but not limited to, verifying the coverage may include verifying identification information related to the service area (e.g., cell ID, coverage ID, space area ID, footprint ID) and measuring the signal strength received from the terminal (101) on the service area (e.g., signal strength calculated in dBm (decibel milliwatts) units).As a non-limiting example, checking the above resources may include checking available resources as well as checking the bandwidth and / or load level of the cell of the terminal (101).

[0221] In operation (S544), the satellite (111) may transmit a service establishment request message to the terminal (101). The service establishment request message may include resource allocation information. Meanwhile, in operation (S543), the base station (134) may transmit a service activation message to the terminal (103). The service activation message may include resource allocation information. The initiation of the service on the cell of the satellite (111) may be performed independently of the initiation of the service on the cell of the base station (134). When the service establishment is completed through operations (S543) and (S544), it may be understood that the data transmission path for the DTC communication service is activated (S550).

[0222] For example, the above service establishment request message may have the following format.

[0223]

[0224] For example, the above service activation message may have the following format.

[0225]

[0226] In operation (S546a), the terminal (101) can transmit data to the satellite (111). For example, the data may be short messages, voice packets, and / or internet traffic. According to one embodiment, the terminal (101) can transmit the data to the satellite (111) via a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band).

[0227] In operation (S546b), the satellite (111) can transmit data to the satellite (114). According to one embodiment, the satellite (111) can transmit data to the satellite (114) via optical communication.

[0228] In operation (S546c), the satellite (114) can transmit data to the satellite (113). According to one embodiment, the satellite (114) can transmit data to the satellite (113) via optical communication.

[0229] In operation (S546d), the satellite (113) can transmit data to the Earth ground station (121). According to one embodiment, the satellite (113) can transmit the data to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0230] In operation (S548), the earth ground station (121) can transmit data to the base station (134). The earth ground station (121) can transmit the data to the base station (134) through the network path of the service network (125) of the satellite operator (120) and the network path of the system network (135) of the mobile network operator (130).

[0231] In operation (S549), the base station (134) can transmit data to the terminal (103). The base station (134) can transmit data to the terminal (103). The base station (134) can transmit the data to the terminal (103) on the cell of the base station (134). The data may be a signal according to a corresponding communication protocol (e.g., LTE, NR standard) on the band of a cellular network.

[0232] Data transmitted through operation (S546a), operation (S546b), operation (S546c), operation (S546d), operation (S548), and / or operation (S549) may include a payload intended to be transmitted to the terminal (103) of the terminal (101), as well as control parameters for the payload. For example, a message containing the data may have the following format.

[0233]

[0234] Although not illustrated in FIGS. 5a and 5b, when the location of a target terminal (e.g., terminal (103)) is searched (e.g., receiving an inquiry message requesting location-related information of the terminal), if the location management device (127) does not store data of the target terminal, the location management device (127) may transmit a response indicating that location-related information of the target terminal cannot be found. If the target terminal is not in the data, or if the number of searches or the search time has been exceeded, or if it is difficult to access the database, the location management device (127) may transmit an error response to the Earth ground station (121) that transmitted the inquiry message.

[0235] Although not illustrated in FIGS. 5a and 5b, if requirements for the link between two nodes in the data transmission path are not met, or if retransmission attempts occur above a threshold due to an error, the receiver may send an error response to the sender. In response to the error response, the satellite (111) may provide a message to the terminal (101) indicating that a path needs to be reset or that a new session for data transmission needs to be established.

[0236] Various tables defining the format of the message in each procedure of FIG. 5a and FIG. 5b have been exemplified, but the tables described above are exemplary and are not to be interpreted as limiting the embodiments of the present disclosure. According to one embodiment, at least some of the IEs of each table may be omitted. According to another embodiment, additional information may be added to each table and transmitted as a single message.

[0237] FIGS. 6a and 6b illustrate examples of signaling of network entities in a second communication scenario using a satellite. Identical reference numbers may be used for identical or similar descriptions. In the second communication scenario, an example of configuring a data transmission path including a satellite is described in a procedure in which a terminal (103) transmits data to a terminal (101).

[0238] Referring to FIGS. 6a and 6b, in operation (S601), the terminal (103) may transmit a service request to the base station (134). The service request may be used to initiate a communication service for data transmission between the terminal (103) and the terminal (101). According to one embodiment, the service request may include identification information of the terminal (101) (e.g., ID of the terminal (101)). The terminal (101) may transmit the service request to the satellite (111) through a cell provided by the base station (134). As an example, but not limited to, the service request may have the format of [Table 2].

[0239] In operation (S602), a location management device (127) (e.g., HLNR) may obtain location-related information of at least one terminal (e.g., terminal (101)) located on a non-terrestrial network through a satellite operator (120) (e.g., service network (125)). According to embodiments of the present disclosure, the location-related information may include identification information of the terminal, location of the terminal, network status connected to the terminal (e.g., connection availability, amount of available resources, number of connected terminals), and / or network type of the cell to which the terminal is connected (e.g., whether it is a terrestrial network, network ID, whether it is a non-terrestrial network, connected satellite ID, and / or satellite group ID to which the connected satellite belongs, operator network ID to which the terminal is connected (e.g., PLMN ID)). The location management device (127) may include a database configured to manage location-related information per terminal. A location management device (127) may be configured to manage location-related information for terminals (e.g., terminal (103)) connected to a base station of a terrestrial network (e.g., base station (134)) as well as terminals (e.g., terminal (101), terminal (102), and / or terminal (104)) connected to a satellite of a terrestrial network (e.g., satellite (110)) in a hybrid network environment where a non-terrestrial network and a terrestrial network coexist. According to one embodiment, the location management device (127) may obtain location-related information of a terminal (e.g., terminal (101)) from an external device (e.g., satellite (111) connected to terminal (101)). The location management device (127) may obtain location-related information of various terminals periodically or upon request. The location management device (127) may store the obtained location-related information for each terminal in a table. The table may store a list of terminals and location-related information of each terminal as data. For example, a location management device (127) can receive a registration request message having the format of [Table 3] from a satellite (111) via a service network (125).

[0240] In operation (S603), the base station (134) may transmit an inquiry message to request location-related information of the terminal (101). The base station (134) may transmit the inquiry message to a device of the system network (135) (e.g., a network entity of the system network (135). The base station (134) does not know whether the terminal (101) is using a non-terrestrial network or is connected to another base station of a terrestrial network. Therefore, the base station (134) may transmit the inquiry message to verify the location of the terminal (101). For example, if the terminal (103) is subscribed to the communication service of a mobile network operator (130) associated with a satellite operator (120), the base station (134) may transmit the inquiry message to an entity of the system network (135) without using a separate data network. As another example, if the terminal (103) is not subscribed to the communication service of the mobile network operator (130) associated with the satellite operator (120), the base station (134) may transmit the inquiry message to an entity of the mobile network operator (130) via a separate data network. The inquiry message may be transmitted to a location management device (127). The inquiry message may include information about the terminal (101) (e.g., ID of the terminal (101)). For example, the inquiry message may have the format of [Table 4].

[0241] In operation (S604), the location management device (127) may receive an inquiry message from a base station (134) via a system network (135) (e.g., a server device of the system network (135)). When the location management device (127) receives an inquiry message from the base station (134), it may obtain identification information of the terminal (101) included in the inquiry message. The location management device (127) may identify data associated with the identification information of the terminal (101) within a database. The data may include location data of the terminal (101), the network status of the terminal (101) (e.g., availability of resources, available bandwidth, base station ID, cell ID, PLMN (public land mobile network) ID), etc.), and / or information regarding the network type of the terminal (101) (e.g., presence of a terrestrial network, connected telecommunications carrier, base station placement, etc.). In response to the inquiry message, the location management device (127) may identify data associated with the terminal (101) stored in the database. The location management device (127) can transmit a response message containing the data to the Earth ground station (121). For example, the response message may have the format of [Table 4-1].

[0242] In operation (S606), the location management device (127) may transmit a response message containing location-related information corresponding to the terminal (101) to a server of the system network (135) (e.g., a location management entity, a location management server (LMF)). Through the response message, it may be confirmed that the terminal (101) is connected to the satellite (111) of the satellite operator (120) on the side of the mobile network operator (130). The location management server of the mobile network operator (130) may transmit the response message to the Earth ground station (121) through the system network (135) and the service network (125). The location management server may provide the Earth ground station (121) with location-related information of the terminal (103) as well as location-related information of the terminal (101) so that the Earth ground station (121) can establish a data transmission path.

[0243] In operation (S608), the Earth ground station (121) may receive a response message containing location-related information corresponding to the terminal (101) via the system network (135) (e.g., a server device of the system network (135)). Although not illustrated in FIG. 6a, the response message may also be transmitted to a base station (134) as an example, but not limited to. The base station (134) may transmit the response message to the terminal (103). The response message may be used to inquire whether the terminal (103) will communicate with a user connected to the satellite. In response to the acceptance response of the terminal (103), the base station (134) may transmit the response message to the Earth ground station (121).

[0244] In operation (S610), the Earth ground station (121) can determine a data transmission path. The Earth ground station (121) can determine the data transmission path based on location-related information. A data transmission path may represent a signal transmission path from a source terminal (e.g., terminal (101)) to a destination terminal (e.g., terminal (103)). For example, the Earth ground station (121) can obtain the location of the terminal (103) connected to the base station (134). The Earth ground station (121) can obtain location-related information of the terminal (101) (e.g., location of terminal (103), network connection information of terminal (103)) through the response message of operation (S608). The satellite (111) can configure the data transmission path based on the location of the terminal (101), the location of the terminal (103), and / or information about the network connected to the terminal (103). Since the terminal (101) is connected to the satellite (111), the Earth ground station (121) can determine a data transmission path that includes the satellite (111). For example, if the satellite (111) can be directly connected to the Earth ground station (121), the Earth ground station (121) can determine the data transmission path so as not to include any other satellites besides the satellite (111). For example, if it is difficult for the satellite (111) to be directly connected to the Earth ground station (121), the Earth ground station (121) can determine a data transmission path that includes at least one ISL.

[0245] In operation (S612), the Earth ground station (121) can identify an ISL path. The Earth ground station (121) can identify an ISL path of a data transmission path. According to one embodiment, the Earth ground station (121) can determine a starting location and a destination location. For example, the Earth ground station (121) can use identification information of the satellite (113) and location information of the satellite (113) as the starting location. For example, the Earth ground station (121) can use identification information of the satellite (111) and location information of the satellite (111) as the destination location. According to one embodiment, the Earth ground station (121) can use various parameters to determine the ISL path. The Earth ground station (121) can use at least one of various parameters to determine an ISL path between satellites. For example, the various parameters may include a maximum number of hops (i.e., the number of allowed transits). The Earth ground station (121) can determine a data transmission path that includes at least one ISL that does not exceed the maximum number of hops. For example, the various parameters may include reference conditions (e.g., delay, bandwidth, reliability). The Earth ground station (121) can determine a data transmission path optimized according to the reference conditions among a number of candidate paths. For example, the various parameters may include information on path constraints (e.g., ISL path indication limited to bitmaps, cross-plane ISL is restricted). The Earth ground station (121) can determine a data transmission path that satisfies the path constraints among a number of candidate paths.

[0246] The Earth ground station (121) can identify an ISL path of a data transmission path for a connection between the satellite (111) and the satellite (113). For example, the Earth ground station (121) can identify an ISL path between the satellite (111) and the satellite (113). The ISL path may include at least one ISL. As another example, the Earth ground station (121) can identify a first ISL between the satellite (111) and the satellite (114) and a second ISL between the satellite (114) and the satellite (113).

[0247] In operation (S614), the Earth ground station (121) can perform path setting. The Earth ground station (121) can set a data transmission path including an ISL path in a satellite network environment where multiple satellites are clustered. The ISL path may be defined by an ISL formed between at least one satellite and / or two satellites. The Earth ground station (121) can generate path information representing the data transmission path. For example, the Earth ground station (121) can generate path information configured in a format such as {ISL #1: ID of satellite (111), ID of satellite (114), ISL #2: ID of satellite (114), ID of satellite (113)}. For example, the path information may have the format of [Table 5].

[0248] In operation (S616), the Earth ground station (121) may transmit a forward request to the satellite (113). The forward request may be used to determine whether service provision is possible (e.g., whether the terminal is located within coverage, whether available resources are available) in the network of the recipient (e.g., terminal (103)) for communication.

[0249] According to one embodiment, the route information may be used for a service connection procedure. The service connection procedure may include a resource verification procedure based on a request from a source terminal (e.g., terminal (103)) and an authentication procedure based on a response from a destination terminal (e.g., terminal (103)). As an example, but not limited to, the route information may be transmitted together with data during data transmission via ISL between satellites.

[0250] In operation (S618), the satellite (113) may transmit a forwarding request to the satellite (114). The forwarding request may be used to determine whether service provision is possible (e.g., whether the terminal is located within coverage, whether available resources are available) in the network of the recipient (e.g., terminal (101)) for communication. The satellite (113) may transmit the forwarding request to the satellite (114) based on the path information. According to one embodiment, the satellite (113) may transmit the forwarding request to the satellite (114) via optical communication. For example, the forwarding request may have the format of [Table 6].

[0251] In operation (S620), the satellite (114) can transmit a transmission request to the satellite (111). The satellite (114) can transmit the transmission request to the satellite (111) based on the path information. According to one embodiment, the satellite (114) can transmit the transmission request to the satellite (111) via optical communication.

[0252] In operation (S625), the satellite (111) can check coverage and / or resources. The satellite (111) can determine whether the terminal (101) is located on the coverage of the cell provided by the satellite (111). The satellite (111) can check the availability of resources. The satellite (111) can obtain information about resources predefined for the cell. The predefined resources may be predefined for the satellite (111)'s DTC communication service. According to one embodiment, the predefined resources may be preconfigured within the satellite (111) before the terminal (101) connects. According to another embodiment, they may be obtained by a separate procedure performed in response to a service request from the terminal (101) (e.g., the satellite (111) requests cellular network resources from the satellite operator (120) or the mobile network operator (130). For example, the above-mentioned predefined resources may represent time-frequency resources on an LTE communication system or a resource grid of an LTE communication system. If a terminal (101) is located on the cell and there are available resources on the cell, the satellite (111) may perform an authentication procedure with the terminal (101).

[0253] Although not illustrated in FIGS. 6a and 6b, the satellite (111) may attempt to reallocate resources or transmit an error response to the delivery request if the terminal (101) is not located within the coverage of the cell or if there are no available resources for the terminal (101) within the cell. In a non-limiting example, checking the coverage may include identification information IDs of areas indicating service coverage (e.g., cell ID, area ID, space area ID, footprint ID), location information of the area (e.g., coordinate data), and / or status information of the area (e.g., fully available, partially available, unavailable). In a non-limiting example, checking the resource status may include checking additional resource parameters in addition to checking available resources. The resource parameters may include resource types (e.g., bandwidth, power, time slots), information on the amount of resources required, and / or information on the amount of resources available. Route setting may fail depending on the error response. In this case, upon receiving the error response, the Earth ground station (121) can search for an alternative route.

[0254] In operation (S627), the satellite (111) can transmit a notification message to the terminal (101). The satellite (111) can transmit the notification message to the terminal (101) on the cell of the satellite (111). The notification message may be a signal according to the corresponding communication protocol (e.g., LTE, NR standard) on the band of the cellular network. Based on the notification message, the terminal (101) can perform a connection with the satellite (111) (e.g., receiving a synchronization signal, random access procedure). For example, the notification message may have a format such as [Table 7].

[0255] As a non-limiting example, the connection state of the terminal (101) may change to the RRC CONNECTED state upon receiving the notification message while in the RRC (radio resource control) IDLE state. For example, in terms of the change in the connection state, the notification message may be referred to as a paging message. The terminal (101) may be configured to monitor the notification message according to the period of the notification message (e.g., 'Interval' IE).

[0256] In operation (S629), the satellite (111) may transmit an authentication request message to the terminal (101). The authentication request message may include an inquiry to the terminal (101) regarding whether to allow data transmission with the terminal (103). For example, the authentication request message may include identification information of the terminal (103). For example, the authentication request message may include information related to the authentication of the terminal (103). As an example, the information related to the authentication of the terminal (103) may have the format of [Table 8].

[0257] In operation (S631), the terminal (101) may transmit an authentication response message to the satellite (111). The authentication response message may indicate that the terminal (101) allows data transmission from the terminal (103). For example, the authentication response message may correspond to the authentication request message. As an example, the authentication response message may have the format of [Table 9].

[0258] In operation (S633), the satellite (111) may transmit an authentication response message to the satellite (114). The authentication response message may correspond to the response message of operation (S631). According to one embodiment, the satellite (111) may transmit the authentication response message to the satellite (114) via optical communication.

[0259] In operation (S635), the satellite (114) may transmit an authentication response message to the satellite (113). The authentication response message may correspond to the response message of operation (S631) and / or operation (S633). According to one embodiment, the satellite (114) may transmit the authentication response message to the satellite (113) via optical communication.

[0260] In operation (S637), the satellite (113) can transmit an authentication response message to the Earth ground station (121). According to one embodiment, the satellite (113) can transmit the authentication response message to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0261] In operation (S639), the Earth ground station (121) can transmit an authentication response message to the base station (134). The Earth ground station (121) can transmit the authentication response message to the base station (134) through the service network (125) of the satellite operator (120) and the system network (135) of the mobile network operator (130).

[0262] In operation (S641), the base station (134) can check coverage and / or resources. The base station (134) can determine whether the terminal (103) is located on the coverage of the cell provided by the base station (134). The base station (134) can determine whether there are available resources on the cell. If the terminal (103) is located on the coverage of the cell and there are available resources on the cell, the base station (134) can perform a service connection procedure with the terminal (103). Although not illustrated in FIGS. 6a and 6b, if the terminal (103) is not located on the coverage of the cell or there are no available resources on the cell, the base station (134) can send a rejection response to the service request of operation (S601) to the terminal (103). In a non-limiting example, verifying the coverage may include verifying identification information related to the service area (e.g., cell ID, coverage ID) and measuring the signal strength received from the terminal (103) over the service area (e.g., calculating the signal strength in dBm units). In a non-limiting example, verifying the resources may include not only verifying available resources but also verifying the bandwidth and / or load level of the cell of the terminal (103).

[0263] In operation (S643), the base station (134) may transmit a service activation message to the terminal (103). The service activation message may include resource allocation information. For example, the service activation message may have the format of [Table 11]. In operation (S644), the satellite (111) may transmit a service establishment request message to the terminal (101). The service establishment request message may include resource allocation information. For example, the service establishment request message may have the format of [Table 10]. The initiation of the service on the cell of the satellite (111) may be performed independently of the initiation of the service on the cell of the base station (134). When the service establishment is completed through operations (S643) and (S644), it may be understood that the data transmission path for the DTC communication service is activated (S670).

[0264] In operation (S645), the terminal (103) can transmit data to the base station (134). For example, the data may be short message, voice packet, and / or internet traffic.

[0265] In operation (S647), the base station (134) can transmit data to the earth ground station (121). According to one embodiment, the base station (134) can transmit data to the earth ground station (121) through the network path of the service network (125) of the satellite operator (120) and the network path of the system network (135) of the mobile network operator (130).

[0266] In operation (S649), the Earth ground station (121) can transmit data to the satellite (113). According to one embodiment, the Earth ground station (121) can transmit the data to the satellite (113) through a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0267] In operation (S651), the satellite (113) can transmit data to the satellite (111). According to one embodiment, the satellite (113) can transmit data to the satellite (111) via optical communication. According to another embodiment, the satellite (113) can transmit the data to the satellite (111) via the ISL path between the satellite (113) and the satellite (114) and the ISL path between the satellite (114) and the satellite (111). Optical communication can be performed over the ISL path between the satellite (113) and the satellite (114). Optical communication can be performed over the ISL path between the satellite (114) and the satellite (114).

[0268] In operation (S653), the satellite (111) can transmit data to the terminal (101). According to one embodiment, the satellite (111) can transmit the data to the terminal (101) through a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). The terminal (101) can receive the data through a DTC communication service.

[0269] Although not illustrated in FIGS. 6a and 6b, if requirements for the link between two nodes in the data transmission path are not met, or if retransmission attempts occur above a threshold due to an error, the receiver may send an error response to the sender. In response to the error response, the earth ground station (121) may reconfigure the path. Additionally, in response to the error, the base station (134) may provide a message to the terminal (103) indicating that a new session for data transmission needs to be established.

[0270] FIG. 7 illustrates an example of signaling of network entities in a third communication scenario using a satellite. The same reference numbers may be used for the same or similar descriptions. In the third communication scenario, an example is described of configuring a data transmission path including a satellite in a procedure in which a terminal (101) transmits data to a terminal (104). The communication service of FIG. 7 may be referred to as a DTD communication service.

[0271] Referring to FIG. 7, in operation (S701), the terminal (101) may transmit a service request to the satellite (111). The service request may be used to initiate a DTC communication service (including a DTD communication service) for data transmission between the terminal (101) and the terminal (104). According to one embodiment, the service request may include identification information of the terminal (103) (e.g., ID of the terminal (104)). The terminal (101) may transmit the service request to the satellite (111) via a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). For example, the service request may be an uplink message (e.g., PUSCH) on an LTE or NR standard. For example, if telephone services are to be performed via DTC, the service request may correspond to a SIP (session initiation protocol) INVITE message. The service request may have the format of [Table 2].

[0272] In operation (S702), a location management device (127) (e.g., HLNR) may obtain location-related information of at least one terminal (e.g., terminal (104)) through a system network (135) of a mobile network operator (130). According to embodiments of the present disclosure, the location-related information may include identification information of the terminal, the location of the terminal, the status of the network connected to the terminal (e.g., whether it is connected, the amount of available resources, the number of connected terminals), and / or the network type of the cell to which the terminal is connected (e.g., whether it is a terrestrial network, network ID, whether it is a non-terrestrial network, connected satellite ID, and / or the satellite group ID to which the connected satellite belongs, and the operator network ID to which the terminal is connected (e.g., PLMN ID)). The location management device (127) may include a database configured to manage location-related information per terminal. The location management device (127) may be configured to manage location-related information for terminals (e.g., terminal (103)) connected to a base station of a ground network (e.g., base station (134)) as well as terminals (e.g., terminal (101), terminal (102), and / or terminal (104)) connected to a satellite of a non-ground network (e.g., satellite (110)) in a hybrid network environment where a non-ground network and a ground network coexist.

[0273] According to one embodiment, the location management device (127) may obtain location-related information of a terminal from an external device (e.g., a server of a satellite operator (120), a server of a mobile network operator (130). The location management device (127) may obtain location-related information of various terminals periodically or upon request. The location management device (127) may store the obtained location-related information for each terminal in a table. The table may store a list of terminals and location-related information of each terminal as data. The location management device (127) may be configured to update the table whenever it obtains information regarding the location of a terminal. For example, registering the location-related information of a terminal to the location management device (127) by an external device may include the external device transmitting a registration request message having the format of [Table 3] to the location management device (127).

[0274] In FIG. 7a, the operation (S702) is depicted as being described after the operation (S701), but embodiments of the present disclosure are not limited thereto. The operation (S702) may be performed periodically and may be performed before the operation (S701).

[0275] In operation (S703), the satellite (111) may transmit an inquiry message to the Earth ground station (121) to request location-related information of the terminal (104). The inquiry message may correspond to the inquiry message of operation (S503). The inquiry message may include identification information of the terminal (104) (e.g., ID of the terminal (104)). According to one embodiment, the satellite (113) may transmit the inquiry message to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band). For example, the inquiry message may have the format of [Table 4].

[0276] In operation (S704), the Earth ground station (121) may send an inquiry message to the location management device (127) to request location-related information of the terminal (104). The inquiry message may correspond to the inquiry message of operation (S703). The inquiry message may include identification information of the terminal (104) (e.g., ID of the terminal (104)). The Earth ground station (121) may connect to the location management device (127) through the service network (125) of the satellite operator (120). The Earth ground station (121) may send the inquiry message to the location management device (127) through the service network (125).

[0277] In operation (S705), the location management device (127) may transmit a response message containing location-related information corresponding to the terminal (104) to the earth ground station (121). When the location management device (127) receives an inquiry message from the earth ground station (121), it may obtain identification information of the terminal (104) included in the inquiry message. The location management device (127) may identify data associated with the identification information of the terminal (104) within a database. The data may include location data of the terminal (104), information on the network status of the terminal (103) (e.g., availability of resources, available bandwidth, base station ID, cell ID, PLMN (public land mobile network) ID), etc.), and / or information on the network type of the terminal (103) (e.g., availability of a ground network, connected telecommunications carrier, base station placement, etc.). The inquiry message may respond to a request for location-related information corresponding to the terminal (12). The location management device (127) may, in response to the request, transmit a response message containing data associated with the terminal (104) stored in the database to the Earth ground station (121). The location management device (127) may transmit the response message to the Earth ground station (121) via the service network (125). For example, the response message may have the format of [Table 4-1].

[0278] In operation (S706), the Earth ground station (121) may transmit a response message containing location-related information of the terminal (104) to the satellite (111). The response message may correspond to the response message of operation (S705). The Earth ground station (121) may transmit the response message to the satellite (111), which is an access satellite. According to one embodiment, the Earth ground station (121) may transmit the inquiry message to the satellite (111) through a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0279] In operation (S707), the satellite (111) can check coverage and / or resources. The satellite (111) can determine whether the terminal (104) is located on the coverage of the cell provided by the satellite (111). The satellite (111) can check the availability of resources. The satellite (111) can obtain information about resources predefined for the cell. The predefined resources may be predefined for the satellite (111)'s DTC communication service. For example, the predefined resources may represent time-frequency resources on an LTE communication system or a resource grid of an LTE communication system. If the terminal (104) is located on the coverage of the cell and there are available resources on the cell, the satellite (111) can perform an authentication procedure with the terminal (104). In a non-limiting example, verifying the coverage may include verifying identification information related to the service area (e.g., cell ID, coverage ID, space area ID, footprint ID) and measuring the signal strength received from the terminal (104) over the service area (e.g., signal strength calculated in dBm units). In a non-limiting example, verifying the resources may include not only verifying available resources but also verifying the bandwidth and / or load level of the cell of the terminal (104).

[0280] In operation (S708), the satellite (111) can transmit a notification message to the terminal (104). The satellite (111) can transmit the notification message to the terminal (104) on the cell of the satellite (111). The notification message may be a signal according to the corresponding communication protocol (e.g., LTE, NR standard) on the band of the cellular network. Based on the notification message, the terminal (104) can perform a connection to the cell of the satellite (111). The cell associated with the terminal (104) may be independent of the cell associated with the terminal (101). For example, the cell ID of the terminal (101) (e.g., PCI (physical cell identity)) may be different from the cell ID of the terminal (104). For example, the notification message may have a format such as [Table 7]. As a non-limiting example, since the satellite (111) is already connected to the terminal (104), the procedure for transmitting the notification message may be omitted.

[0281] In operation (S709), the satellite (111) may transmit an authentication request message to the terminal (104). The authentication request message may include an inquiry to the terminal (104) regarding whether to allow data transmission with the terminal (101). For example, the authentication request message may include identification information of the terminal (101). For example, the authentication request message may include information related to the authentication of the terminal (101). As an example, the information related to the authentication of the terminal (101) may have the format of [Table 8]. As another example, the information related to the authentication of the terminal (101) may have the format of the table below.

[0282]

[0283] In operation (S711), the terminal (104) can transmit an authentication response message to the satellite (111). The terminal (104) can transmit an authentication response message to the satellite (111). The authentication response message may indicate that the terminal (104) allows data transmission from the terminal (101). For example, the authentication response message may correspond to the authentication request message. As an example, the authentication response message may have the format of [Table 9].

[0284] In operation (S713), the satellite (111) can check coverage and / or resources. The satellite (111) can determine whether the terminal (101) is located on the coverage of the cell provided by the satellite (111). The satellite (111) can check the availability of resources. The satellite (111) can obtain information about resources predefined for the cell. The predefined resources may be predefined for the satellite (111)'s DTC communication service. According to one embodiment, the predefined resources may be preconfigured within the satellite (111) before the terminal (101) connects. According to another embodiment, they may be obtained by a separate procedure performed in response to a service request from the terminal (101) (e.g., the satellite (111) requests cellular network resources from the satellite operator (120) or the mobile network operator (130). For example, the aforementioned predefined resources may represent time-frequency resources on an LTE communication system or a resource grid of an LTE communication system. If a terminal (101) is located in the coverage of the cell and there are available resources on the cell, the satellite (111) may perform a service connection procedure (e.g., operation (S715), operation (S717)). In an example, not limited to, checking the coverage may include checking identification information related to the service area (e.g., cell ID, coverage ID, space area ID, footprint ID) and measuring the signal strength received from the terminal (101) on the service area (e.g., signal strength calculated in dBm units). In an example, not limited to, checking the resources may include checking the available resources as well as checking the bandwidth and / or load level of the cell of the terminal (101).

[0285] In operation (S715), the satellite (111) may transmit a service establishment request message to the terminal (104). The service establishment request message may include resource allocation information. The satellite (111) may transmit the service establishment request message to the terminal (104) on the second cell. In operation (S717), the satellite (111) may transmit a service establishment request message to the terminal (101). The service establishment request message may include resource allocation information. The satellite (111) may transmit the service establishment request message to the terminal (101) on the first cell. For example, the service establishment request message of operation (S715) and / or operation (S717) may have the following format.

[0286]

[0287] When the service establishment is completed through operations (S715) and (S717), it can be understood that a data transmission path for the DTC communication service (i.e., D2D communication service) is activated (S750).

[0288] In operation (S719), the terminal (101) can transmit data to the satellite (111). For example, the data may be short messages, voice packets, and / or internet traffic. According to one embodiment, the terminal (101) can transmit the data on the first cell to the satellite (111). The terminal (101) can transmit the data to the satellite (111) according to the communication standard of the cellular network (e.g., LTE, NR).

[0289] In operation (S721), the satellite (111) can transmit data to the terminal (104). According to one embodiment, the satellite (111) can transmit the data to the terminal (104) over the second cell. The satellite (111) can transmit the data to the terminal (104) according to the communication standard of the cellular network (e.g., LTE, NR). For example, the data of operation (S719) and / or operation (S721) can be transmitted via a message having the following format.

[0290]

[0291] In FIG. 7, a procedure is described in which the satellite (111) inquires with the location management device (127) to identify the location of the terminal (104), but embodiments of the present disclosure are not limited thereto. The satellite (111) can identify that the terminal (104) is connected to a cell provided by the satellite (111). Based on the identification, the satellite (111) can identify that a DTD communication service is available. In response to identifying that a DTD communication service is available, the satellite (111) can immediately send a notification message to the terminal (104) without going through a separate location lookup procedure.

[0292] FIGS. 8a and 8b illustrate examples of signaling of network entities in a fourth communication scenario using a satellite. Identical reference numbers may be used for identical or similar descriptions. In the fourth communication scenario, an example of configuring a data transmission path including a satellite is described in a procedure in which a terminal (101) transmits data to a terminal (104).

[0293] Referring to FIGS. 8a and 8b, in operation (S801), the terminal (101) may transmit a service request to the satellite (111). The service request may be used to initiate a DTC communication service for data transmission between the terminal (101) and the terminal (102). According to one embodiment, the service request may include identification information of the terminal (103) (e.g., ID of the terminal (102)). The terminal (101) may transmit the service request to the satellite (111) via a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). For example, the service request may be an uplink message (e.g., PUSCH) on an LTE or NR standard. For example, if telephone services are to be performed via DTC, the service request may correspond to a SIP (session initiation protocol) INVITE message. The service request may have the format of [Table 2].

[0294] In operation (S802), a location management device (127) (e.g., HLNR) may obtain location-related information of at least one terminal (e.g., terminal (102)) through a system network (135) of a mobile network operator (130). According to embodiments of the present disclosure, the location-related information may include identification information of the terminal, the location of the terminal, the status of the network connected to the terminal (e.g., whether it is connected, the amount of available resources, the number of connected terminals), and / or the network type of the cell to which the terminal is connected (e.g., whether it is a terrestrial network, network ID, whether it is a non-terrestrial network, connected satellite ID, and / or the satellite group ID to which the connected satellite belongs, and the operator network ID to which the terminal is connected (e.g., PLMN ID)). The location management device (127) may include a database configured to manage location-related information per terminal. The location management device (127) may be configured to manage location-related information for terminals (e.g., terminal (103)) connected to a base station of a ground network (e.g., base station (134)) as well as terminals (e.g., terminal (101), terminal (102), and / or terminal (104)) connected to a satellite of a non-ground network (e.g., satellite (110)) in a hybrid network environment where a non-ground network and a ground network coexist.

[0295] According to one embodiment, the location management device (127) may obtain location-related information of a terminal from an external device (e.g., a server of a satellite operator (120), a server of a mobile network operator (130). The location management device (127) may obtain location-related information of various terminals periodically or upon request. The location management device (127) may store the obtained location-related information for each terminal in a table. The table may store a list of terminals and location-related information of each terminal as data. The location management device (127) may be configured to update the table whenever it obtains information regarding the location of a terminal. For example, registering the location-related information of a terminal to the location management device (127) by an external device may include the external device transmitting a registration request message having the format of [Table 3] to the location management device (127).

[0296] In operation (S803), the satellite (111) may transmit an inquiry message to the satellite (113) to request location-related information of the terminal (104). The satellite (111) may obtain information about the terminal (104) (e.g., ID of the terminal (104)) from the service request of the terminal (101). The satellite (111) may transmit the inquiry message containing information about the terminal (104) (e.g., ID of the terminal (103)) to the satellite (113). The satellite (113) is a satellite connected to the Earth ground station (121) and may be referred to as an access satellite. In order to obtain information about the location and network type of the counterpart terminal, the satellite (111) is required to be connected to a location management device (127) located on the ground. The satellite (111) may transmit the inquiry message to the satellite (113) which is capable of connecting to the location management device (127). According to one embodiment, the satellite (111) can transmit the inquiry message to the satellite (113) via optical communication (e.g., laser communication using near-infrared light). For example, the inquiry message may have the format of [Table 4].

[0297] In operation (S804), the satellite (113) may transmit an inquiry message to the Earth ground station (121) to request location-related information of the terminal (104). The inquiry message may correspond to the inquiry message of operation (S803). The inquiry message may include identification information of the terminal (104) (e.g., ID of the terminal (104)). According to one embodiment, the satellite (113) may transmit the inquiry message to the Earth ground station (121) via a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0298] In operation (S806), the Earth ground station (121) may send an inquiry message to the location management device (127) to request location-related information of the terminal (104). The inquiry message may correspond to the inquiry message of operation (S803) and / or operation (S804). The inquiry message may include identification information of the terminal (104) (e.g., ID of the terminal (104)). The Earth ground station (121) may access the location management device (127) through the service network (125) of the satellite operator (120). The Earth ground station (121) may send the inquiry message to the location management device (127) through the service network (125).

[0299] In operation (S808), the location management device (127) may transmit a response message containing location-related information corresponding to the terminal (104) to the earth ground station (121). When the location management device (127) receives an inquiry message from the earth ground station (121), it may obtain identification information of the terminal (104) included in the inquiry message. The location management device (127) may identify data associated with the identification information of the terminal (104) within a database. The data may include information regarding the location data of the terminal (104), the network status of the terminal (104) (e.g., availability of resources, available bandwidth, base station ID, cell ID, PLMN (public land mobile network) ID), etc.), and / or the network type of the terminal (104) (e.g., presence of a ground network, connected telecommunications carrier, base station placement, etc.). The inquiry message may respond to a request for location-related information corresponding to the terminal (104). The location management device (127) may, in response to the request, transmit a response message containing data associated with the terminal (104) stored in the database to the Earth ground station (121). The location management device (127) may transmit the response message to the Earth ground station (121) via the service network (125). For example, the response message may have the format of [Table 4-1].

[0300] In operation (S810), the Earth ground station (121) may transmit a response message containing location-related information of the terminal (104) to the satellite (113). The response message may correspond to the response message of operation (S808). The Earth ground station (121) may transmit the response message to the satellite (113), which is an access satellite. According to one embodiment, the Earth ground station (121) may transmit the response message to the satellite (113) through a satellite frequency band (e.g., Ka band, Ku band, V band, E band).

[0301] In operation (S812), the satellite (111) can determine a data transmission path. The satellite (111) can determine the data transmission path based on location-related information of the terminal (104). The data transmission path may include a satellite (e.g., satellite (111)) that provides DTC services and may represent a signal transmission path from a source terminal (e.g., terminal (101)) to a destination terminal (e.g., terminal (104)). For example, the satellite (111) can obtain the location of the terminal (101) that is connected to the cell of the satellite (111). The satellite (111) can obtain location-related information of the terminal (104) (e.g., location of the terminal (104), network connection information of the terminal (104)) through the response message of operation (S512). The satellite (111) can configure a data transmission path based on information regarding the location of the terminal (101), the location of the terminal (104), and / or the network to which the terminal (104) is connected. For example, since the terminal (104) is connected to a ground network, the satellite (111) can determine a data transmission path including a satellite (e.g., satellite (113)) that is connectable to an earth ground station (e.g., earth ground station (121)), at least some path of the service network (125) of the satellite operator (120), at least some path of the system network (135) of the mobile network operator (130), and a base station (134). According to one embodiment, the satellite (111) can determine whether DTD communication service is available based on identifying that the network to which the terminal (104) is connected is a non-ground network (e.g., the access network of the satellite (112)). To determine whether DTD communication service is available, the satellite (111) can determine whether an ISL path to the satellite (112) is found. If the ISL path is found, the satellite (111) can determine that DTD communication service is available.

[0302] In operation (S814), the satellite (111) can identify an ISL path. The satellite (111) can identify an ISL path of a data transmission path for connection with the satellite (112). According to one embodiment, the satellite (111) can determine a starting position (starting satellite) and a destination position (destination satellite). For example, the satellite (111) can use identification information of the satellite (111) and location information of the satellite (111) as the starting position. For example, the satellite (111) can use identification information of the satellite (112) and location information of the satellite (112) as the destination position. According to one embodiment, the satellite (111) can use various parameters to determine the ISL path. The satellite (111) can use at least one of various parameters to determine an ISL path between satellites. For example, the various parameters may include a maximum number of hops (i.e., the number of allowed transits). The satellite (111) can determine a data transmission path that includes at least one ISL that does not exceed the maximum number of hops. For example, the various parameters may include reference conditions (e.g., delay, bandwidth, reliability). The satellite (111) can determine a data transmission path optimized according to the reference conditions among a number of candidate paths. For example, the various parameters may include information on path constraints (e.g., ISL path indication limited to bitmaps, cross-plane ISL is restricted). The satellite (111) can determine a data transmission path that satisfies the path constraints among a number of candidate paths.

[0303] The satellite (111) can identify an ISL path of a data transmission path for a connection between the satellite (111) and the satellite (114). For example, the satellite (111) can identify a first ISL path between the satellite (111) and the satellite (114) and a second ISL path between the satellite (114) and the satellite (112).

[0304] In operation (S816), the satellite (111) can perform path setting. The satellite (111) can set a data transmission path including an ISL path in a satellite network environment where multiple satellites are clustered. The ISL path may be defined by an ISL formed between at least one satellite and / or two satellites. The satellite (111) can generate path information representing the data transmission path. For example, the satellite (111) can generate path information configured in a format such as {ISL #1: ID of satellite (111), ID of satellite (114), ISL #2: ID of satellite (114), ID of satellite (113)}. For example, the path information may have the format of [Table 5].

[0305] In operation (S818), the satellite (111) may transmit a forward request to the satellite (114). The forward request may be used to determine whether service provision is possible (e.g., whether the terminal is located within coverage, whether available resources are available) in the network of the recipient (e.g., terminal (103)) for communication. The satellite (111) may transmit the forward request to the satellite (114) based on the path information. The satellite (114) may be referred to as a gateway satellite as an intermediary used to form an ISL path between two satellites. According to one embodiment, the satellite (111) may transmit the forward request to the satellite (114) via optical communication (e.g., laser communication using near-infrared light). For example, the forward request may have the format of [Table 6].

[0306] In operation (S820), the satellite (114) can transmit a transmission request to the satellite (112). The satellite (114) can transmit the transmission request to the satellite (112) based on the path information. According to one embodiment, the satellite (114) can transmit the transmission request to the satellite (112) via optical communication (e.g., laser communication using near-infrared light). For example, the transmission request may have the format of [Table 6].

[0307] In operation (S822), the satellite (112) can check coverage and / or resources. The satellite (112) can determine whether the terminal (102) is located on the coverage of the cell provided by the satellite (112). The satellite (112) can determine whether there are available resources on the cell. If the terminal (102) is located on the coverage of the cell and there are available resources on the cell, the satellite (112) can perform an authentication procedure with the terminal (102). The authentication procedure is described through FIG. 5b. Although not illustrated in FIG. 8a and FIG. 8b, the satellite (112) can transmit an error response to the transmission request if the terminal (102) is not located on the coverage of the cell or if there are no available resources for the terminal (102) on the cell. By example, without limitation, checking the coverage may include identification information IDs of areas representing service coverage (e.g., cell ID, coverage ID, space area ID, footprint ID), location information of said areas (e.g., coordinate data), and / or status information of said areas (e.g., fully available, partially available, unavailable). By example, without limitation, checking the resource status may include checking available resources as well as checking additional resource parameters. said resource parameters may include resource types (e.g., bandwidth, power, time slots), information on the amount of resources required, and / or information on the amount of resources available.

[0308] In operation (S824), the satellite (112) can transmit a notification message to the terminal (103). The satellite (112) can transmit the notification message to the terminal (103) on the cell of the satellite (112). The notification message may be a signal according to the corresponding communication protocol (e.g., LTE, NR standard) on the band of the cellular network. Based on the notification message, the terminal (103) can establish a connection with the satellite (112). For example, the notification message may have a format such as [Table 7]. As a non-limiting example, the transmission procedure of the notification message may be omitted.

[0309] In operation (S826), the satellite (112) may transmit an authentication request message to the terminal (103). The authentication request message may include an inquiry to the terminal (103) regarding whether to allow data transmission with the terminal (101). For example, the authentication request message may include identification information of the terminal (101). For example, the authentication request message may include information related to the authentication of the terminal (101). As an example, the information related to the authentication of the terminal (101) may have the format of [Table 8].

[0310] In operation (S828), the terminal (102) may transmit an authentication response message to the satellite (112). The authentication response message may indicate that the terminal (102) allows data transmission from the terminal (101). For example, the authentication response message may correspond to the authentication request message. As an example, the authentication response message may have the format of [Table 9].

[0311] In operation (S830), the satellite (112) may transmit an authentication response message to the satellite (114). The authentication response message may correspond to the response message of operation (S828). According to one embodiment, the satellite (112) may transmit the authentication response message to the satellite (114) via optical communication.

[0312] In operation (S832), the satellite (114) may transmit an authentication response message to the satellite (111). The authentication response message may correspond to operation (S828) and / or the response message of operation (S828). According to one embodiment, the satellite (114) may transmit the authentication response message to the satellite (111) via optical communication.

[0313] In operation (S834), the satellite (111) can check coverage and / or resources. The satellite (111) can determine whether the terminal (101) is located on the coverage of the cell provided by the satellite (111). The satellite (111) can check the availability of resources. The satellite (111) can obtain information about resources predefined for said cell. The predefined resources may be predefined for the satellite (111)'s DTC communication service. According to one embodiment, the predefined resources may be preconfigured within the satellite (111) before the terminal (101) connects. According to another embodiment, they may be obtained by a separate procedure performed in response to a service request from the terminal (101) (e.g., the satellite (111) requests cellular network resources from the satellite operator (120) or the mobile network operator (130). For example, the aforementioned predefined resources may represent time-frequency resources on an LTE communication system or a resource grid of an LTE communication system. If a terminal (101) is located over the coverage of the cell and there are available resources on the cell, the satellite (111) may perform an operation (S544). In an example that is not limited, checking the coverage may include checking identification information related to the service area (e.g., cell ID, coverage ID, space area ID, footprint ID) and measuring the signal strength received from the terminal (101) over the service area (e.g., signal strength calculated in dBm units). In an example that is not limited, checking the resources may include checking the available resources as well as checking the bandwidth and / or load level of the cell of the terminal (101).

[0314] In operation (S836), the satellite (111) may transmit a service establishment request message to the terminal (101). The service establishment request message may include resource allocation information. Meanwhile, in operation (S837), the satellite (114) may transmit a service establishment request message to the terminal (102). The service establishment request message may include resource allocation information. The initiation of a service on the cell of the satellite (111) may be performed independently of the initiation of a service on the cell of the satellite (114). When the service establishment is completed through operations (S836) and (S837), it may be understood that a data transmission path for the DTC communication service (i.e., DTD communication service) is activated (S850). For example, the service establishment request message may have the format of [Table 10].

[0315] In operation (S838), the terminal (101) can transmit data to the satellite (111). For example, the data may be short messages, voice packets, and / or internet traffic. According to one embodiment, the terminal (101) can transmit the data to the satellite (111) via a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band).

[0316] In operation (S840), the satellite (111) can transmit data to the satellite (114). According to one embodiment, the satellite (111) can transmit data to the satellite (114) via optical communication.

[0317] In operation (S842), the satellite (114) can transmit data to the satellite (112). According to one embodiment, the satellite (114) can transmit data to the satellite (112) via optical communication.

[0318] In operation (S844), the satellite (112) can transmit data to the terminal (102). According to one embodiment, the satellite (112) can transmit the data to the terminal (102) through a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). The terminal (102) can receive the data through a DTC communication service.

[0319] In FIGS. 5a, 5b, 6a, 6b, 7, 8a, and 8b, signal flow when communication between network entities is successful is illustrated, but the embodiments of the present disclosure are not limited thereto. A DTC service system according to the embodiments of the present disclosure may provide an error response message to improve service reliability and efficient error management. The error response message is intended to effectively process and transmit error situations that may occur at each stage within the DTC communication system.

[0320] By transmitting the above error response message, rapid error detection and response may be possible. For example, since relevant information is transmitted in response to the occurrence of an error, it may be possible to perform situation-optimized recovery procedures. This can improve the stability of the DTC communication system. Furthermore, through the above error response message, unnecessary resources are not wasted in error situations, thereby improving system efficiency. The scheduler can improve the resource efficiency of the entire DTC communication system by reallocating resources based on priority. By utilizing the above error response message, service reliability and monitoring functions (e.g., error pattern analysis, accident prevention) can be improved. According to one embodiment, the above error response message may include information related to the error that occurred and / or recovery information related to necessary measures in response to the error. For example, the above error response message may have the following format.

[0321]

[0322] The error response message described above can be used in various stages. According to one embodiment, the error response message can be used in a service request procedure. A node that receives a service request (e.g., satellite (110), base station (134)) can transmit an error message in response to the service request. For example, the error response message can be transmitted when there is a shortage of resources on the cell provided by the node, when authentication of the terminal is difficult, or when the target terminal of the service request is incorrect information.

[0323] According to one embodiment, the error response message may be used in the step of querying location-related information. Querying location-related information refers to the process in which a node that has received a service request sends an inquiry message to a location management device (e.g., a location management device (127)) to obtain location-related information of a target terminal. If the target terminal is not in the data, the inquiry count or inquiry time has been exceeded, or access to the database is difficult, the location management device (127) may send an error response message to the node that sent the inquiry message.

[0324] According to one embodiment, the error response message may be performed during the resource verification step. For example, a satellite (e.g., satellite (110)) or a base station (e.g., base station (134)) may transmit the error response message to the node that transmitted the forwarding request based on the determination that there are insufficient available resources in the cell or that the current cell is overloaded.

[0325] According to one embodiment, the error response message may be performed during the path setting step. For example, if an ISL path between satellites for transmitting data is not found, a satellite (e.g., satellite (110)) or an Earth ground station (e.g., Earth ground station (121)) may transmit the error response message to the node that transmitted the response message.

[0326] According to one embodiment, the error response message may be performed during the authentication procedure step. For example, if the authentication information is inconsistent, the authentication time has expired, or the security policy has been violated, the authentication processing entity (e.g., terminal (101), terminal (103)) may send the error response message to the node that sent the authentication request message (e.g., satellite (110), earth ground station (121)).

[0327] FIG. 9 shows the operation flow of a satellite (e.g., satellite (111)) for establishing a satellite path.

[0328] Referring to FIG. 9, in operation (901), a satellite (e.g., satellite (111)) may receive a service request. The satellite (111) may receive a service request from a terminal (e.g., terminal (101)). The service request is a request from a terminal (101) using a DTC communication service, and the service request may include identification information for a target terminal (e.g., terminal (103)). According to one embodiment, the satellite (111) may identify that the network connected to the target terminal is a terrestrial network through a location lookup procedure with a location management device (127) (e.g., HLNR). The satellite (111) may perform operation (903) to establish a data transmission path.

[0329] In operation (903), the satellite (111) can determine whether it is possible to connect with an Earth ground station (ESG) (e.g., Earth ground station (121)). If the satellite (111) is directly connected to the Earth ground station (121), it may be referred to as an access satellite. If the satellite (111) determines that it is not possible to connect with the Earth ground station (121), it may perform operation (905). If the satellite (111) determines that it is possible to connect with the Earth ground station (121), it may perform operation (913).

[0330] In operation (905), the satellite (111) can perform an ISL path search. The satellite (111) can identify a starting satellite and a destination satellite from a list of multiple connectable satellites. The satellite (111) can determine at least one candidate ISL path connecting the starting satellite and the destination satellite. The satellite (111) can determine at least one candidate ISL path based on at least one of various parameters. For example, the various parameters may include a maximum number of hops (i.e., the number of allowed transits). The satellite (111) can determine a candidate path so as not to exceed the maximum number of hops. For example, the various parameters may include reference conditions (e.g., delay, bandwidth, reliability). The satellite (111) can determine a candidate path optimized according to the reference conditions from among multiple candidate paths.

[0331] In operation (907), the satellite (111) can determine whether a path can be constructed solely of In-plane ISL. For example, the satellite (111) can identify whether there is a path composed solely of In-plane ISL among at least one candidate ISL path. As another example, the satellite (111) can determine whether a target satellite shares the orbit of the satellite (111). The satellite (111) can determine that if the target satellite shares the orbit of the satellite (111), a path can be constructed solely of In-plane ISL. The satellite (111) can perform operation (909) based on the determination that a path can be constructed solely of In-plane ISL. The satellite (111) can perform operation (911) based on the determination that a path cannot be constructed solely of In-plane ISL.

[0332] In operation (909), the satellite (111) can establish a path including an in-plane ISL. The satellite (111) can establish a data transmission path to transmit data via optical communication (e.g., laser communication using near-infrared light) depending on the direction of the orbit. The satellite (111) can transmit a message for path establishment to a satellite in the same orbit.

[0333] In operation (911), the satellite (111) may establish a path that includes a cross-plane ISL. The satellite (111) may establish a data transmission path to transmit data via optical communication (e.g., laser communication using near-infrared light) toward a satellite located in another orbit. For example, the data transmission path may include only at least one cross-plane ISL. For example, the data transmission path may include at least one cross-plane ISL and at least one in-plane ISL. The satellite (111) may transmit a message for path establishment to an adjacent satellite in the same orbit or to a satellite in a different orbit. As an example, but not limited to, the satellite (111) may establish a path that includes the least amount of cross-plane ISL as a data transmission path.

[0334] In operation (913), the satellite (111) can establish a path with the Earth ground station (121). The satellite (111) can transmit a message for establishing a path to the Earth ground station (121) on a satellite frequency band (e.g., a Ku band of about 12 to 18 GHz, a Ka band of about 26.5 GHz to 40 GHz, a V-band of about 40 GHz to 75 GHz, or an E-band of about 60 GHz to 95 GHz).

[0335] FIG. 10 shows the flow of operation of an earth ground station (e.g., earth ground station (121)) for establishing a satellite path.

[0336] Referring to FIG. 10, in operation (1001), a ground station (e.g., a ground station (121)) may receive a service request from a mobile network operator (e.g., a satellite operator (120)). The service request is a request from a terminal (103) using a DTC communication service, and the service request may include identification information for a target terminal (e.g., a terminal (101)). According to one embodiment, the ground station (121) may identify that the network the terminal (101) is connected to is a non-ground network through a location lookup procedure with a location management device (127) (e.g., HLNR). The ground station (121) may identify that the terminal (101) is connected to a satellite (111) through a location lookup procedure with a location management device (127). The ground station (121) may perform operation (1003) to establish a data transmission path.

[0337] In operation (1003), the Earth ground station (121) can determine whether it is possible to connect with a target satellite (e.g., satellite (111)). Connectability between the Earth ground station (121) and the target satellite (e.g., satellite (111)) may indicate direct connection. If the Earth ground station (121) is directly connected to the target satellite, the target satellite may be referred to as an access satellite. The Earth ground station (121) may perform operation (1005) based on the determination that it is not possible to connect with the target satellite (e.g., satellite (111)). The Earth ground station may perform operation (1013) based on the determination that it is possible to connect with the target satellite (e.g., satellite (111)).

[0338] In operation (1005), the Earth ground station (121) can perform an ISL path search. The Earth ground station (121) can identify a starting satellite (i.e., an access satellite) (e.g., satellite (113)) and a destination satellite (i.e., a satellite connected to the destination terminal) (e.g., satellite (111)) from a list of multiple connectable satellites. The Earth ground station (121) can determine at least one candidate ISL path connecting the starting satellite and the destination satellite. The Earth ground station (121) can determine at least one candidate ISL path based on at least one of various parameters. For example, the various parameters may include a maximum number of hops (i.e., the number of allowed transits). The satellite (111) can determine a candidate path so as not to exceed the maximum number of hops. For example, the various parameters may include reference conditions (e.g., delay, bandwidth, reliability). The satellite (111) can determine an optimized candidate path among a number of candidate paths according to the above criteria conditions.

[0339] In operation (1007), the Earth ground station (121) can determine whether a path can be constructed using only In-plane ISL. For example, the Earth ground station (121) can identify whether there is a path composed only of In-plane ISL among at least one candidate ISL path. As another example, the Earth ground station (121) can determine whether the target satellite shares the orbit of the satellite (111). The Earth ground station (121) can determine that if the target satellite shares the orbit of the satellite (111), a path can be constructed using only In-plane ISL. The Earth ground station (121) can perform operation (1009) based on the determination that a path can be constructed using only In-plane ISL. The Earth ground station (121) can perform operation (1013) based on the determination that a path cannot be constructed using only In-plane ISL.

[0340] In operation (1009), the Earth ground station (121) can establish a path including an In-plane ISL. The Earth ground station (121) can transmit a message for establishing a path to an access satellite. The message for establishing a path can be transmitted over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz).

[0341] In operation (1011), the Earth ground station (121) may establish a path including a Cross-plane ISL. For example, the data transmission path may include only at least one Cross-plane ISL. For example, the data transmission path may include at least one Cross-plane ISL and at least one In-plane ISL. The Earth ground station (121) may transmit a message for path establishment to an access satellite. The message for path establishment may be transmitted over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz).

[0342] In operation (1013), the Earth ground station (121) can establish a path with the target satellite (e.g., satellite (113)). The target satellite may be an access satellite. The Earth ground station (121) may transmit a message for establishing a path to the target satellite. The message for establishing a path may be transmitted over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz).

[0343] FIG. 11 illustrates the flow of operations of an Earth ground station (e.g., Earth ground station (121)) for selecting a satellite (e.g., satellite (111), satellite (113)). To support DTC communication services, the Earth ground station (121) may be required to be connected to a satellite. In order to transmit information about a terminal accessing the satellite to the ground, the satellite is required to be connected to the Earth ground station (121) directly on the ground or to the Earth ground station (121) through an access satellite.

[0344] Referring to FIG. 11, in operation (1101), an Earth ground station (e.g., Earth ground station (121)) may perform satellite scanning. According to one embodiment, the Earth ground station (121) may be configured to monitor a signal being broadcast from a satellite. If the signal is above a threshold value, the Earth ground station (121) may include the satellite in a list of satellites for connection. According to one embodiment, the Earth ground station (121) may identify a list of multiple candidate satellites based on pre-stored satellite information. Each candidate satellite may be moving along an orbit. The Earth ground station (121) may identify a satellite adjacent to the geographical coverage of the Earth ground station (121) among the candidate satellites in the list. The Earth ground station (121) may include the identified satellite in a list of satellites for connection. According to one embodiment, the Earth ground station (121) may include a satellite moving along the same orbit as a previously connected satellite in the list of satellites for connection. According to one embodiment, the Earth ground station (121) may broadcast a signal of inquiry. A satellite that receives the signal of inquiry may transmit a response. The Earth ground station (121) may include the satellite that transmitted the response in a list of satellites for connection. For example, the response may include information on the identification of the satellite, the orbit information of the satellite, the number of satellites located in-plane of the satellite, the beam steering capability of the satellite, the movement speed of the satellite, the capability of the satellite, the number of terminals that can connect to the satellite, whether the satellite supports DTC communication, whether the satellite supports DTD communication, and / or information on frequency bands that can be provided by the satellite.

[0345] In operation (1103), the Earth ground station (121) can identify a satellite that satisfies a triggering condition from a list of satellites. The identified satellite may correspond to an access satellite. The triggering condition may be used to find a satellite that will form a feeder link with the Earth ground station (121) from a list of satellites for connection. The satellite may be referred to as an access satellite. According to one embodiment, if the list of satellites includes one satellite, the Earth ground station (121) can identify the one satellite as an access satellite. According to one embodiment, if the list of satellites includes a plurality of satellites, the Earth ground station (121) can identify an access satellite based on the quality of communication with the satellites. For example, the satellite with the highest communication quality may be identified as an access satellite. As another example, any satellite among the satellites having a communication quality higher than a threshold may be identified as an access satellite. According to one embodiment, the Earth ground station (121) can identify an access satellite based on orbital information. For example, the Earth ground station (121) can determine the expected time of stay for each satellite in the above list of satellites. The Earth ground station (121) can identify the satellite expected to stay the longest within the coverage of the Earth ground station (121) as the access satellite.

[0346] In operation (1105), the Earth ground station (121) may transmit a connection request message to the satellite. The satellite may correspond to an access satellite. The Earth ground station (121) may transmit a connection request message to the satellite on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). According to one embodiment, the connection request message may include a feeder link ID, the validity period of the feeder link, and / or cell configuration information for DTC communication. The feeder link ID and the validity period of the feeder link may be used for a connection between the Earth ground station (121) and the satellite. The cell configuration information may include configuration information for each cell in a cellular frequency band provided by the satellite (e.g., SIB1, MIB, RRC configuration information, cell ID, synchronization sequence information). The information transmitted through the above connection request message can be used for DTC communication services by the satellite.

[0347] In operation (1107), the Earth ground station (121) may receive a connection response message from the satellite. The satellite may correspond to an access satellite. After receiving the connection response message, the Earth ground station (121) may transmit data to the satellite or receive data from the satellite on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). According to one embodiment, the connection response message may include information on the identification information of the satellite, the orbit information of the satellite, the number of satellites located in-plane of the satellite, the beam steering capability of the satellite, the movement speed of the satellite, the capability of the satellite, the number of terminals that can connect to the satellite, whether the satellite supports DTC communication, whether the satellite supports DTD communication, and / or information on frequency bands that can be provided by the satellite. The information received through the above connection response message can be used to establish a data transmission path at the Earth ground station (121).

[0348] FIG. 12 shows the flow of operation of a satellite (e.g., satellite (110)) for selecting an Earth ground station (e.g., Earth ground station (121)).

[0349] Referring to FIG. 12, in operation (1201), the satellite (110) can transmit a broadcast signal. The satellite (110) may be configured to periodically broadcast the broadcast signal. The satellite (110) may move along an orbit. When the satellite (110) is located within the coverage of the Earth ground station (121), the Earth ground station (121) can receive the broadcast signal. For example, the broadcast signal may be transmitted over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz).

[0350] In operation (1203), the satellite (110) may receive a response to a broadcast signal from an earth ground station (e.g., earth ground station (121)). According to one embodiment, the earth ground station (121) may generate the response when the broadcast signal is above a threshold value. For example, the response may be transmitted over a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). According to one embodiment, the response may include identification information. The identification information may be used to identify a feeder link between the satellite (110) and the earth ground station (121). According to one embodiment, the response may include resource allocation information. The resource allocation information may be used to indicate a channel on the feeder link between the satellite (110) and the earth ground station (121). The above channel may be a part of the above satellite frequency band.

[0351] In operation (1205), the satellite (110) may transmit a connection request message to the Earth ground station (121). The satellite (110) may transmit a connection request message to the Earth ground station (121) on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). According to one embodiment, the connection request message may include information regarding the identification information of the satellite, the orbit information of the satellite, the number of satellites located in-plane of the satellite, the beam steering capability of the satellite, the movement speed of the satellite, the capability of the satellite, the number of terminals that can connect to the satellite, whether the satellite supports DTC communication, whether the satellite supports DTD communication, and / or information regarding frequency bands that can be provided by the satellite. The information received through the connection response message may be used to establish a data transmission path at the Earth ground station (121).

[0352] In operation (1207), the satellite (110) may receive a connection response message from the Earth ground station (121). The satellite (110) may receive the connection response message from the Earth ground station (121) on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz). The connection response message may include a feeder link ID, the validity period of the feeder link, and / or cell configuration information for DTC communication. The feeder link ID and the validity period of the feeder link may be used for a connection between the Earth ground station (121) and the satellite (110). The cell configuration information may include configuration information for each cell in the cellular frequency band provided by the satellite (110) (e.g., SIB1, MIB, RRC configuration information, cell ID, synchronization sequence information). The information transmitted through the above connection response message can be used for DTC communication services by the satellite.

[0353] FIG. 13 shows examples (1300) of components of a satellite (e.g., satellite (110), satellite (111), satellite (112), satellite (113), satellite (114)). Terms such as '...part', '...device', '...object', or '...body' used below may mean at least one shape structure or a unit that processes a function.

[0354] Referring to FIG. 13, the satellite (110) may include a processor (1310), a memory (1320), and a communication circuit (1330). The processor (1310) controls the overall operations of the satellite (110). The processor (1310) may be referred to as a control unit. For example, the processor (1310) writes and reads data to and from the memory (1320). Additionally, the processor (1310) transmits and receives signals through the communication circuit (1330). The processor (1310) may perform the functions of a protocol stack required by a communication standard. Although only the processor (1310) is shown in FIG. 13, according to other embodiments, the satellite (110) may include two or more processors. The processor (1310) may include a circuitry configured to execute a set of instructions, instructions, and / or code stored in the memory (1320). As a non-limiting example, the processor (1310) may have a space for temporarily storing at least some of the instruction set, the instructions, and / or the code for the execution of a function.

[0355] A processor (1310) can control the satellite (110) to perform operations according to embodiments of the present disclosure. The processor (1310) may include a path setting unit (1311) and a cell management unit (1312). Each of the path setting unit (1311) and the cell management unit (1312) may be a set of instructions, instructions, and / or code that are executed by the processor (1310) or temporarily reside in the processor (1310). According to one embodiment, the path setting unit (1311) may be configured to determine a data transmission path including an ISL path. For example, the satellite (110) may set a data transmission path for a connection with another terminal (e.g., terminal (103)) connected to a ground network in response to a request from a terminal (e.g., terminal (101)) connected via a mobile network. According to one embodiment, the cell management unit (1312) may be configured to manage one or more cells provided by the satellite (110). For example, the cell management unit (1312) can store and manage the cell ID (e.g., PCI) and cell-specific configuration information (e.g., system information, MIB (master information block), SIB (system information block)) of each of the satellite (110) and one or more cells provided by the satellite (110). For example, the cell management unit (1312) can be configured to generate signals (e.g., PSS (primary synchronization signal), SSS (secondary synchronization signal), MIB, SIB) according to the communication protocol (e.g., LTE, NR) of the cell so that a terminal connecting to the cell can recognize it as a cell in an actual cellular network.

[0356] The memory (1320) stores data such as basic programs, applications, and configuration information for the operation of the satellite (110). The memory (1320) may be referred to as a storage unit. The memory (1320) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Additionally, the memory (1320) provides the stored data upon the request of the processor (1310).

[0357] According to one embodiment, the memory (1320) may store cell-pre-configuration information (1321). The cell-pre-configuration information (1321) may include a cell-specific pre-configuration. The satellite (110) may be configured to provide an access network. A terminal may connect to a cell provided by the satellite (110). Since the terminal must connect to the satellite (110) via cellular communication, the satellite is required to receive a configuration according to the protocol of said cellular communication from a mobile network operator (e.g., mobile network operator (130)) or to store in advance a cell-specific configuration that can be provided by the satellite (110). Since the satellite is constantly moving, the satellite (110) may include a pre-configuration of said cell so that the satellite can provide basic information about the cell to a terminal attempting to connect to said cell. For example, the cell-pre-configuration information (1321) may include a cell ID (identity). The satellite (110) can transmit a synchronization signal (e.g., PSS, SSS) generated based on the cell ID. For example, the cell-preconfiguration information (1321) may include a cell-specific MIB. For example, the MIB may include bandwidth and a system frame number. For example, the cell-preconfiguration information (1321) may include a cell-specific SIB. For example, the cell-preconfiguration information (1321) may include system information broadcast before attempting a connection, such as SIB1 or SIB2. SIB1 may include cell configuration information, random access related settings, and / or scheduling information for other system information.

[0358] According to one embodiment, the memory (1320) may store satellite information (1322). Satellite information (1322) may represent information about each of the satellite (110) and one or more satellites adjacent to the satellite (110). For example, the satellite information (1322) may include information about the orbit of each satellite (e.g., orbit ID, orbit characteristics). For example, the satellite information (1322) may include information about the status of each satellite (e.g., speed, orbit, number of connectable terminals, maximum number of cells, ISL support, Cross-plane ISL support, supported communication capability). For example, the satellite information (1322) may include a list of satellites that support DTC communication services.

[0359] The communication circuit (1330) may be configured to perform functions for transmitting and receiving signals. The communication circuit (1330) may include an optical communication circuit (1331), a satellite communication circuit (1332), and a cellular communication circuit (1333). According to embodiments of the present disclosure, the optical communication circuit (1331) may support communication with other satellites. Since satellites must track each other precisely and aim beams very accurately, high attitude control technology may be required. The optical communication circuit (1331) may be connected to an antenna panel that is connected to or mounted on the satellite (110). Optical communication with other satellites may be performed through the antenna panel. The optical communication circuit (1331) may modulate a digital signal and transmit the modulated signal through an optical carrier. The signal may be input to an optical modulator, and the intensity of light and / or the satellite may be changed. The signal modified in this way can be transmitted to other satellites (e.g., satellites equipped with a concentrator or a photodetector) through beamforming.

[0360] According to embodiments of the present disclosure, the communication circuit (1330) may include a satellite communication circuit (1332). The satellite communication circuit (1332) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the satellite communication circuit (1332) may perform a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the satellite communication circuit (1332) generates complex-valued symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the satellite communication circuit (1332) restores the received bit sequence through demodulation and decoding of the baseband signal. The satellite communication circuit (1332) may include a plurality of transmission and reception paths. According to one embodiment, the satellite communication circuit (1332) may be configured to transmit or receive signals on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz) to communicate with a satellite moving along an orbit. As an example, but not limited to, an Earth ground station (121) may communicate with the satellite (e.g., satellite (113)) on a cellular band. In this case, the satellite (110) may use a cellular communication circuit (1333).

[0361] According to embodiments of the present disclosure, the communication circuit (1330) may include a cellular communication circuit (1333). The cellular communication circuit (1333) may be configured to transmit or receive signals in a cellular communication band, such as a smartphone used by users on the ground. The cellular communication circuit (1333) may transmit or receive signals on a cellular frequency band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band). The cellular communication circuit (1333) upconverts a baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. To this end, the cellular communication circuit (1333) may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Additionally, the cellular communication circuit (1333) may include a plurality of transmitting and receiving paths. Although not shown in FIG. 13, the satellite (110) may include a plurality of antennas (e.g., array antennas) connected to the cellular communication circuit (1333). The cellular communication circuit (1333) may be configured to transmit generated RF signals through the antennas. The cellular communication circuit (1333) may be configured to process RF signals received through the antennas.

[0362] The communication circuit (1330) transmits and receives signals as described above. Accordingly, all or part of the communication circuit (1330) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter / receiver unit'. Additionally, in the description above, the transmission and reception performed may be used to mean that processing as described above is performed by the communication circuit (1330).

[0363] FIG. 14 shows examples (1400) of components of an earth ground station (e.g., an earth ground station (121)). Terms such as ‘...part’, ‘...device’, ‘...object’, or ‘...body’ used below may mean at least one shape structure or a unit that performs a function.

[0364] Referring to FIG. 14, the Earth ground station (121) may include a processor (1410), memory (1420), and communication circuit (1430). The processor (1410) controls the overall operations of the Earth ground station (121). The processor (1410) may be referred to as a control unit. For example, the processor (1410) writes and reads data to and from the memory (1420). Additionally, the processor (1410) transmits and receives signals through the communication circuit (1430). The processor (1410) can perform the functions of a protocol stack required by a communication standard. Although only the processor (1410) is shown in FIG. 14, according to other embodiments, the Earth ground station (121) may include two or more processors. The processor (1410) may include a circuit configured to execute a set of instructions, instructions, and / or code stored in the memory (1420). As a non-limiting example, the processor (1410) may have a space for temporarily storing at least some of the instruction set, the instructions, and / or the code for the execution of a function.

[0365] The processor (1410) can control the Earth ground station (121) to perform operations according to embodiments of the present disclosure. The processor (1410) may include a path setting unit (1411) and a satellite management unit (1412). Each of the path setting unit (1411) and the satellite management unit (1412) may be a set of instructions, instructions, and / or code that are executed by the processor (1410) or temporarily reside in the processor (1410). According to one embodiment, the path setting unit (1411) may be configured to determine a data transmission path including an ISL path for two adjacent satellites among one or more satellites including a satellite (i.e., a gate satellite) connected to the Earth ground station (121). For example, the Earth ground station (121) may establish a data transmission path for a connection with another terminal (e.g., terminal (101)) using a DTC communication service in response to a request from a terminal (e.g., terminal (103)) connected via a mobile network. According to one embodiment, the satellite management unit (1412) may be configured to manage satellites connected to the Earth ground station (121). For example, the satellite management unit (1412) may store and manage a list of satellites that can be connected to the Earth ground station (121). The satellite management unit (1412) may identify access satellites to configure an ISL path. The satellite management unit (1412) may determine an access satellite among at least one satellite entering the coverage of the Earth ground station (121). The Earth ground station (121) may determine a subsequent access satellite through the orbit of each satellite. For example, the Earth ground station (121) may determine a subsequent access satellite by another satellite that is in-plane with the current access satellite. The Earth ground station (121) may determine a subsequent access satellite through the orbit of each satellite. For example, the Earth ground station (121) may determine a subsequent access satellite by a satellite that is different from the plane of the current access satellite, that is, a satellite that is in a cross-plane.

[0366] The memory (1420) stores data such as basic programs, application programs, and configuration information for the operation of the Earth ground station (121). The memory (1420) may be referred to as a storage unit. The memory (1420) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The memory (1420) provides stored data upon request from the processor (1310). According to one embodiment, the memory (1420) may store satellite information (1422). The satellite information (1422) may represent information regarding each of the satellites managed by the Earth ground station (121). For example, the satellite information (1422) may include information regarding the orbit of each satellite (e.g., orbit ID, orbit characteristics). For example, satellite information (1422) may include information regarding the status of each satellite (e.g., speed, orbit, number of connectable terminals, maximum number of cells, ISL support, Cross-plane ISL support, supported communication capabilities). For example, satellite information (1422) may include a list of satellites that support DTC communication services. Based on the list of satellites, the Earth ground station (121) may configure a data transmission path in response to a service request. For example, satellite information (1422) may include information regarding broadcast signals transmitted from the satellite. Information regarding the broadcast signals may be used by the Earth ground station (121) to identify the corresponding satellite.

[0367] The communication circuit (1430) may be configured to perform functions for transmitting and receiving signals. The communication circuit (1430) may include a wired communication circuit (1431) and a satellite communication circuit (1432). According to embodiments of the present disclosure, the wired communication circuit (1431) may perform functions for transmitting and receiving signals in a wired communication environment (e.g., an Ethernet environment). The wired communication circuit (1431) may include a wired interface for controlling a direct connection between devices through a transmission medium (e.g., copper wire, optical fiber). For example, the wired communication circuit (1431) may transmit an electrical signal to another device through a copper wire or perform conversion between an electrical signal and an optical signal. For example, the wired communication circuit (1431) may be connected to the system network (135) of the mobile network operator (130) through the network of the satellite operator (120). For example, a wired communication circuit (1431) can transmit data received from a satellite to a base station (134) of a mobile network operator (130).

[0368] According to embodiments of the present disclosure, the communication circuit (1430) may include a satellite communication circuit (1432). The satellite communication circuit (1432) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the satellite communication circuit (1432) may perform a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the satellite communication circuit (1432) generates complex-valued symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the satellite communication circuit (1432) restores the received bit sequence through demodulation and decoding of the baseband signal. The satellite communication circuit (1432) may include a plurality of transmission and reception paths. According to one embodiment, the satellite communication circuit (1432) may be configured to transmit or receive signals on a satellite frequency band (e.g., a Ku band of about 12–18 GHz, a Ka band of about 26.5 GHz–40 GHz, a V-band of about 40 GHz–75 GHz, or an E-band of about 60 GHz–95 GHz) to communicate with a satellite moving along an orbit. As an example, but not limited to, the Earth ground station (121) may communicate with the satellite (e.g., satellite (113)) on a cellular band. In this case, the satellite communication circuit (1432) may transmit or receive signals on a general cellular band (e.g., B2 band, B4 band, B5 band, B12 band, B13 band, B25 band, B41 band, B55 band, or B71 band) instead of a satellite frequency band.

[0369] The communication circuit (1430) transmits and receives signals as described above. Accordingly, all or part of the communication circuit (1430) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter / receiver unit'. Additionally, in the description above, the transmission and reception performed may be used to mean that processing as described above is performed by the communication circuit (1430).

[0370] FIG. 15 shows examples (1500) of components of a position management device (position management device (127)). Terms such as '...part', '...device', '...object', or '...body' used below may mean at least one shape structure or a unit that processes a function.

[0371] Referring to FIG. 15, the position management device (127) may include a processor (1510), a memory (1520), and a communication circuit (1530). The processor (1510) controls the overall operations of the satellite (110). The processor (1510) may be referred to as a control unit. For example, the processor (1510) writes and reads data to and from the memory (1520). Additionally, the processor (1510) transmits and receives signals through the communication circuit (1530). The processor (1510) may perform the functions of a protocol stack required by the communication standard. Although only the processor (1510) is shown in FIG. 15, according to other embodiments, the position management device (127) may include two or more processors. The processor (1510) may include a circuit configured to execute a set of instructions, instructions, and / or code stored in the memory (1520). As a non-limiting example, the processor (1510) may have a space for temporarily storing at least some of the instruction set, the instructions, and / or the code for the execution of a function.

[0372] The processor (1510) can control the location management device (127) to perform operations according to embodiments of the present disclosure. The processor (1510) may include a terminal register (1511) and a location-network management unit (1512). Each of the terminal register (1511) and the location-network management unit (1512) may be a set of instructions, instructions, and / or code that are executed by the processor (1510) or temporarily reside in the processor (1510).

[0373] According to embodiments of the present disclosure, the terminal register (1511) may be configured to register location-related information of the terminal. The terminal register (1511) may receive location-related information of the terminal from a server of a satellite operator (120) (e.g., a ground station (121)) or a server of a mobile network operator (130) (e.g., a network entity of a system network (135)). The terminal register (1511) may be configured to store location-related information of the terminal in memory (1520). The location management device (127) may be connected to different operators (e.g., the satellite operator (120) and the mobile network operator (130) may be different operators). Accordingly, the terminal register (1511) may be configured to manage a synchronized data format for requests from different operators.

[0374] According to one embodiment, the terminal register (1511) may receive location-related information in a first format corresponding to a satellite operator (120) from an earth ground station (121). The terminal register (1511) may convert the location-related information in the first format into a second format and then store the data in the second format in memory (1520). The second format may be a location management format used by a mobile network operator (130). The terminal register (1511) may receive location-related information in a second format corresponding to a mobile network operator (130) from a server of the mobile network operator (130) (e.g., a network entity of a system network (135)). The terminal register (1511) may store the location-related information in the second format in memory (1520) without a separate operator-conversion process. As a non-limiting example, the location management device (127) may be included in the system network (135) of the mobile network operator (130).

[0375] According to another embodiment, the terminal register (1511) may receive location-related information in a second format corresponding to the mobile network operator (130) from a server of the mobile network operator (130) (e.g., a network entity of the system network (135)). The terminal register (1511) may convert the location-related information in the second format into a first format and then store the data in the first format in memory (1520). The first format may be a location management format used by the satellite operator (120). The terminal register (1511) may receive location-related information in a first format corresponding to the mobile network operator (130) from a server of the satellite operator (120) (e.g., a ground station (121), a service network (125)). The terminal register (1511) may store the location-related information in the first format in memory (1520) without a separate operator-conversion process. As a non-limiting example, the location management device (127) may be included in the service network (125) of the satellite operator (120).

[0376] According to another embodiment, the terminal register (1511) may receive location-related information in a second format corresponding to the mobile network operator (130) from a server of the mobile network operator (130) (e.g., a network entity of the system network (135)). The terminal register (1511) may convert the location-related information in the second format into a third format and then store the data in the third format in memory (1520). The third format may be a format defined for managing location-related information in a location-network table (1521). The terminal register (1511) may receive location-related information in a first format corresponding to the mobile network operator (120) from a server of the satellite operator (120) (e.g., a ground station (121), a service network (125)). The terminal registration unit (1511) can convert the location-related information of the first format into the first format and then store the data of the first format in the memory (1520).

[0377] According to embodiments of the present disclosure, a location-network management unit (1512) may receive an inquiry message for requesting location-related information of a terminal. The location-network management unit (1512) may obtain a terminal identifier included in the inquiry message. The location-network management unit (1512) may identify data corresponding to the terminal identifier from a memory (1520). The data may include location-related information of the terminal corresponding to the terminal identifier. The location-network management unit (1512) may transmit a response message corresponding to the inquiry message to the node that transmitted the inquiry message. According to one embodiment, the location-network management unit (1512) may convert data having location-related information of the terminal. The location-network management unit (1512) may convert the data into a format corresponding to the operator that transmitted the inquiry message (i.e., the operator of the node). The location-network management unit (1512) may transmit a response message containing the converted data.

[0378] The memory (1520) stores data such as basic programs, application programs, and configuration information for the operation of the location management device (127). The memory (1520) may be referred to as a storage unit. The memory (1520) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the memory (1520) provides stored data upon a request from the processor (1510). According to one embodiment, the memory (1520) may include a location-network table (1521). The location-network table (1521) may be configured to manage location-related information for each terminal. The location-network table (1521) may include a list of registered terminals. The list of terminals may include terminals connected to a terrestrial network as well as terminals connected to a non-terrestrial network. The location-network table (1521) may include location-related information for each terminal in the list. The location-related information may include network type, network status, connection data, and / or location data. For example, the network type may include information indicating whether the terminal is connected to a terrestrial network or a non-terrestrial network. Additionally, if the terminal is connected to a terrestrial network, a network ID (e.g., PLMN ID, Cell ID, eNB ID) may be further included in the information, and if the terminal is connected to a non-terrestrial network, a satellite ID (e.g., access satellite ID, service satellite ID, satellite group ID)) may be further included. For example, the network status may include the availability of resources, available bandwidth, the number of connected terminals, base station ID, cell ID, and / or PLMN ID.For example, the above location data may include location information of the terminal, information about the satellite's footprint when the terminal is connected to a satellite, geographical information about the physical coverage of the cell of the ground base station when the terminal is connected to a ground base station, and geographical information about the tracking area (TA) to which the terminal belongs.

[0379] The communication circuit (1530) may be configured to perform functions for transmitting and receiving signals. The communication circuit (1530) may perform functions for transmitting and receiving signals in a wired communication environment (e.g., Ethernet environment). The communication circuit (1530) may include a wired interface for controlling a direct connection between devices through a medium (e.g., copper wire, optical fiber). For example, the communication circuit (1530) may transmit electrical signals to another device through a copper wire or perform conversion between electrical signals and optical signals. According to one embodiment, the communication circuit (1530) may be connected to both the network of a mobile network operator (130) (e.g., system network (135)) and the network of a satellite operator (120) (e.g., earth ground station (121) and service network (125)). Through the communication circuit (1530), the location management device (127) may be connected to different operators (or vendors). The communication circuit (1530) may include a mobile network operator connection part (1531) configured to connect to a server of a mobile network operator (130) (e.g., a network entity of a system network (135)). The communication circuit (1530) may include a satellite network operator connection part (1532) configured to connect to a server of a satellite operator (120) (e.g., a ground station (121), a service network (125)).

[0380] The communication circuit (1530) transmits and receives signals as described above. Accordingly, all or part of the communication circuit (1530) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter / receiver unit'. Additionally, in the description above, the transmission and reception performed may be used to mean that processing as described above is performed by the communication circuit (1530).

[0381] FIG. 16 is a flowchart illustrating an AI / ML (Artificial Intelligence / Machine Learning)-based dynamic location prediction method of a location management device (127). This embodiment describes in detail the process of dynamically predicting and managing the location of a terminal in a satellite network environment.

[0382] Referring to FIG. 16, in step S1605, the location management device (127) may receive an inquiry message through a communication circuit (1530). The inquiry message is transmitted from an external node and corresponds to a message requesting location information of a terminal. According to one embodiment, the inquiry message may include a terminal identifier, a request item, and a timestamp. The terminal identifier may be, for example, unique identification information based on IMSI (International Mobile Subscriber Identity) and may be expressed in a string format. The request item may indicate specific request content, such as a location prediction request or a location information lookup. The timestamp includes time information when the message was created and may be expressed, for example, in a UNIX epoch format.

[0383] The processor (1510) can parse and process a query message received from the communication circuit (1530). In one embodiment, the processor (1510) can analyze the query message using a message parsing module, such as a JSON parser or an XML parser, and extract the value of each field. Additionally, the processor (1510) can perform digital signature verification to verify the integrity of the message. For example, it can be confirmed that the message has not been tampered with through signature verification using the RSA-2048 algorithm or the Elliptic Curve Digital Signature Algorithm (ECDSA). Such integrity verification can provide a security level that meets the 3GPP Rel-19 NTN-IoT Radio Resource Management (RRM) requirements.

[0384] In step S1610, the processor (1510) can obtain existing location data by querying a location-network table (1521) stored in memory (1520). The location-network table (1521) may store past location information of the terminal, identification information of connected satellites, tracking area information, geographic coordinates, etc. The processor (1510) can retrieve the recent location records of a specific terminal by executing a database query. For example, location-related information of the terminal recorded within a recent period of time (e.g., 1 hour) can be filtered using a Structured Query Language (SQL) query. The retrieved information may include satellite identifiers, tracking area codes, latitude and longitude coordinates, etc. This data filtering and querying process can be performed efficiently in accordance with 3GPP Rel-19 NTN-IoT RRM requirements.

[0385] In step S1615, the processor (1510) can generate data to be input to a machine learning model. In this embodiment, input data including satellite orbit information and Doppler effect compensation data can be configured to reflect the characteristics of the satellite network environment. The satellite orbit information may include the satellite's movement speed, altitude, and inclination angle, which are important parameters that reflect the dynamic characteristics of a Low Earth Orbit (LEO) satellite. For example, in the case of an LEO satellite, it moves at a speed of about 7.8 km / s, the altitude is about 550 km, and the inclination angle can be expressed as the angle between the satellite orbit plane and the equatorial plane.

[0386] The processor (1510) may construct an input vector containing such satellite orbit information, and the input vector may be represented as multidimensional data. In one embodiment, the input vector may include features between 20 and 30 dimensions and may undergo a normalization process. Normalization may include, for example, a process of adjusting the value of each feature to a certain range (e.g., between 0 and 1) using a min-max scaling technique.

[0387] Additionally, the processor (1510) can compensate for the Doppler effect using the multipath fading compensation technology possessed in the present invention. The Doppler effect caused by the high-speed movement of the satellite causes a frequency shift, which can degrade communication quality. In this embodiment, the quality of input data for a machine learning model can be improved by applying the multipath fading compensation technology to compensate for the frequency shift caused by the Doppler effect. For example, the prediction accuracy of the model can be improved by maintaining the frequency shift caused by the Doppler effect below a certain level (e.g., 100 Hz) and improving the signal-to-noise ratio (SNR) to a certain level (e.g., 10 dB) or higher.

[0388] For training a machine learning model, the processor (1510) can generate a training data set based on past location logs. The training data set may include, for example, terminal movement trajectory data for one month and may consist of a number of samples (e.g., 1,000 samples). The processor (1510) may perform batch learning (e.g., offline learning) and real-time learning (e.g., online learning) in parallel. Batch learning is a method of periodically updating the model by collecting a certain amount of data, while real-time learning is a method of continuously updating the model whenever new data is received. For example, real-time learning may be performed every 10 minutes.

[0389] In addition, in accordance with the 3GPP Rel-19 AI / ML PHY layer integration requirements, the processor (1510) may apply data augmentation techniques. Data augmentation is a technique that improves the generalization performance of a model by increasing the diversity of training data, and, for example, a method of adding Gaussian noise may be used.

[0390] In step S1620, the processor (1510) can predict the future location of the terminal by applying the generated input data to a machine learning model. In this embodiment, a recurrent neural network-based algorithm specialized for time-series data processing may be used. In particular, the Long Short-Term Memory (LSTM) algorithm is suitable for time-series location prediction because it can solve the long-term dependency problem. In one embodiment, the processor (1510) may configure an LSTM model having a plurality of hidden layers, and each hidden layer may include a plurality of nodes.

[0391] The processor (1510) can predict the terminal location after a certain period of time (e.g., after 10 seconds) through the machine learning model. The predicted location can be expressed in latitude and longitude coordinates and may include prediction error information. For example, if the error range of the predicted location is within 50 meters and the reliability is 95% or higher, the prediction can be determined to be reliable.

[0392] To optimize the prediction performance of a machine learning model, the processor (1510) may perform a learning process using an optimizer. For example, the prediction error can be minimized by performing gradient descent using an Adam (Adaptive Moment Estimation) optimizer. The prediction error can be evaluated by metrics such as Mean Absolute Error (MAE) or Root Mean Square Error (RMSE). In this embodiment, high prediction accuracy can be achieved by keeping the MAE below a certain level (e.g., 30m) and the RMSE below a certain level (e.g., 40m).

[0393] This location prediction method can provide the effect of reducing handover delays caused by satellite movement. For example, by predicting the future location of a terminal in advance, handover can be prepared in advance and handover delays can be reduced by a certain percentage (e.g., 20%). This is a performance improvement effect that meets the 3GPP Rel-19 RAN2 CR on AI PHY requirements.

[0394] In step S1625, the processor (1510) may perform a branching decision to determine whether location information exists. Specifically, the processor (1510) may check for the existence of data retrieved in step S1610. The existence of data may be determined through logical operations, for example, by checking whether a database query result exists or whether the number of data is greater than 0.

[0395] This decision process can be performed within a certain time (e.g., 5 to 10 ms), which can satisfy the requirements of real-time location management services. In addition, it can comply with the error tolerance (e.g., less than 1%) specified in the 3GPP Rel-19 NTN-IoT requirements.

[0396] If, as a result of the determination in step S1625, location information exists (Yes), the processor (1510) in step S1630 may generate a response message containing the predicted location information and transmit it to the inquiry node. The response message may include information such as the latitude and longitude coordinates of the predicted location, the prediction error range, and the reliability. The format of the response message may be configured, for example, in JSON (JavaScript Object Notation) or XML (eXtensible Markup Language) format.

[0397] In one embodiment, the processor (1510) may apply a compression algorithm to reduce the size of the response message. For example, bandwidth efficiency may be increased by using gzip compression to reduce the message size by a certain percentage (e.g., 30%). Additionally, the Quality of Service (QoS) for the response message may be set in accordance with the 3GPP Rel-19 AI / ML integration requirements. For example, the response message may be delivered quickly by assigning a high priority.

[0398] On the other hand, if the result of the judgment in step S1625 is that location information does not exist (No), the processor (1510) may generate and transmit an error message in step S1635. The error message may include information such as an error code, the cause of the error, and a retry suggestion. For example, the error code may follow a standard HTTP status code format such as "404 Not Found," and the cause of the error may indicate a specific reason such as "data not present" or "terminal identifier error." The retry suggestion may be expressed as a boolean value and may indicate whether the client is advised to retry the request.

[0399] The processor (1510) can record a detailed log when an error occurs, which can be used for system debugging and performance analysis. The log may include information such as timestamps, error types, and error severity. This error reporting method may follow the format required by the 3GPP Rel-19 RRM standard.

[0400] The AI / ML-based dynamic location prediction method of Fig. 16 described above provides the effect of reducing handover delay and improving communication quality by efficiently predicting and managing the location of a terminal in a satellite network environment.

[0401] FIG. 17 shows a security-enhanced location sharing operation flowchart (1700) of a location management device (127). This embodiment provides a security mechanism for securely sharing location information between operators in a satellite network environment.

[0402] Referring to FIG. 17, in step S1705, the location management device (127) can receive an inquiry message through the communication circuit (1530). In this embodiment, the inquiry message may include authentication information of a node requesting location information. Specifically, the inquiry message may include a node identifier, an authentication token, a timestamp, a carrier identifier, etc.

[0403] The above node identifier is information that uniquely identifies a node requesting location information, and can be expressed, for example, in the form of a Universally Unique Identifier (UUID). A UUID consists of a 36-character string and can provide a globally unique identifier.

[0404] The aforementioned authentication token is a security token that proves the identity of the node and can be configured, for example, in the format of a JSON Web Token (JWT). A JWT is represented as a base64 encoded string and can consist of three parts: a header, a payload, and a signature. The payload may include node identification information, authorization information, the token issuance time, the token expiration time, etc.

[0405] The above operator identifier is information representing the mobile telecommunications operator to which the request node belongs, and can be expressed, for example, in the form of a PLMN ID (Public Land Mobile Network Identifier). The PLMN ID consists of 6 digits and may include a mobile country code (MCC) and a mobile network code (MNC).

[0406] The processor (1510) can parse the inquiry message received from the communication circuit (1530) to extract the value of each field. In the message parsing process, a dedicated parsing module such as a JWT parser may be used, and exception handling may be performed in the event of a parsing error. Additionally, the processor (1510) can perform message validation in accordance with the 3GPP Rel-19 TN-NTN integration requirements. For example, by checking the expiration time of the authentication token to verify whether the token was issued within a certain period of time (e.g., 300 seconds), a replay attack can be prevented.

[0407] In step S1710, the processor (1510) can perform blockchain-based node authentication. This embodiment utilizes distributed ledger technology to prevent information leakage when sharing location data between operators. Specifically, the processor (1510) can verify the identity of the node using a smart contract.

[0408] The smart contract mentioned above is an automated contract program executed on a blockchain network, and can be written in the Solidity language of the Ethereum platform, for example. The smart contract can perform the function of verifying the authentication information of a node and recording the verification result on the blockchain.

[0409] The processor (1510) can verify the integrity of the authentication data by applying a hash function. For example, a hash value of the data combining the authentication token and the node identifier can be calculated using a SHA-256 (Secure Hash Algorithm 256-bit) hash function. The calculated hash value is compared with a value stored in the blockchain, and if they match, it can be determined that the authentication is successful. By applying the hash function, the verification time can be kept within a certain range (e.g., 50 to 100 ms).

[0410] Additionally, the processor (1510) can calculate a node trust score. The trust score is an indicator that comprehensively evaluates the node's past behavior history, authentication success rate, data quality, etc., and can be expressed as a real value between 0 and 1. Location information sharing may be permitted only when the trust score is above a certain threshold (e.g., 0.9). This trust score-based access control can provide the level of security required by 3GPP Rel-19 TN-NTN integration.

[0411] In this embodiment, energy consumption of the authentication process can be reduced by applying the low-power terminal communication technology possessed by the present invention to the authentication process. For example, by using a low-power encryption algorithm or optimizing the amount of computation, energy consumption of the authentication process can be reduced by a certain percentage (e.g., 15%). This can be particularly useful for battery-operated satellite terminals or IoT devices.

[0412] In step S1715, the processor (1510) may perform a branching decision to determine whether authentication is successful. Specifically, the processor (1510) may perform a logical operation based on the hash verification result performed in step S1710 and the blockchain consensus state. For example, if the hash values ​​match (hash_match) and consensus is reached in the blockchain network (consensus_reached), it may be determined that authentication is successful.

[0413] If authentication fails, the processor (1510) may apply access control to deny the provision of location information. Additionally, the authentication failure event may be recorded in a log. The log may include information such as a timestamp, node identifier, cause of failure, and severity level, which can be used for security audits and intrusion detection.

[0414] The decision process can be performed within a certain time (e.g., 10ms), which can satisfy the requirements of real-time services. In addition, it can comply with the error tolerance (e.g., less than 1%) specified in the 3GPP Rel-19 RRM requirements.

[0415] If, as a result of the judgment in step S1715, authentication is successful (Yes), the processor (1510) can encrypt location-related information in step S1720. The location-related information may include a satellite identifier, a tracking area code, geographical coordinates, etc. The processor (1510) can encrypt the location information using a symmetric key encryption algorithm.

[0416] In one embodiment, the Advanced Encryption Standard (AES) algorithm may be used. AES supports key lengths of 128 bits, 192 bits, or 256 bits, and in this embodiment, a 256-bit key may be used for a high level of security. The Cipher Block Chaining (CBC) mode may be used as the encryption operation mode, which can enhance security by making the encryption of each block depend on the ciphertext of the previous block.

[0417] An Initialization Vector (IV) may be used during the encryption process. The said Initialization Vector is a parameter used to increase the randomness of the encryption, and, for example, a 96-bit random nonce may be used. The Initialization Vector is newly generated for each encryption session, which prevents replay attacks.

[0418] In this embodiment, the low-power terminal communication technology possessed by the present invention can be extended and applied as a low-power encryption module. For example, by using a lightweight encryption algorithm based on ECC (Elliptic Curve Cryptography), encryption can be performed efficiently even on low-power devices such as NTN-IoT terminals. ECC can provide an equivalent level of security with a shorter key length compared to RSA, thereby reducing computational load and energy consumption. For example, an ECC algorithm using the secp256r1 curve can be applied.

[0419] Encryption overhead can be kept below a certain level (e.g., 10%), which can satisfy the 3GPP Rel-19 TN-NTN integration requirements.

[0420] In step S1725, the processor (1510) can transmit an encrypted response message to the inquiry node through the communication circuit (1530). The response message may include encrypted location information, encryption metadata (e.g., algorithm used, key identifier, initial vector), etc.

[0421] Security protocols may be used during the data transmission process. For example, an encrypted channel can be established through the HTTPS (Hypertext Transfer Protocol Secure) protocol. In one embodiment, TLS (Transport Layer Security) version 1.3 may be used, and a strong encryption algorithm such as AES-256-GCM may be selected as the cipher suite. By applying these security protocols, compliance with personal data protection regulations such as the GDPR (General Data Protection Regulation) can be achieved.

[0422] Additionally, the processor (1510) can increase bandwidth efficiency by limiting the message size (e.g., less than 1KB). By setting the QoS for the message to give it high priority, the response message can be delivered quickly. This can provide a quality of service that meets 3GPP Rel-19 RRM requirements.

[0423] On the other hand, if authentication fails (No) as a result of the judgment in step S1715, the processor (1510) may transmit an error message in step S1730. The error message may include an error code indicating access denial, the cause of failure, a retry policy, etc.

[0424] For example, error codes may follow standard HTTP status code formats, such as "403 Forbidden," which indicates that the client does not have access to the requested resource. The cause of failure may include specific reasons such as "authentication failure," "token expiration," or "insufficient trust score."

[0425] A retry policy can specify the conditions under which a client can retry a request. For example, an exponential backoff method can be proposed, which gradually increases the retry interval (e.g., 1 second, 2 seconds, 4 seconds, 8 seconds, up to 10 seconds). This can distribute the load on the server and improve system stability.

[0426] The processor (1510) can record a detailed log when an error occurs, and the log may include information such as a timestamp, error type, and severity level. The severity level may be expressed as an integer value from 1 to 5, for example, where a low value indicates a minor error and a high value indicates a serious security threat. This error reporting method may follow the format required by the 3GPP Rel-19 RRM standard.

[0427] The security-enhanced location sharing method of Fig. 17 described above can significantly improve security when sharing location information between operators through blockchain-based distributed authentication and strong encryption, and can contribute to the necessary areas for the development of 3GPP Rel-19 NTN security technology.

[0428] FIG. 18 is a flowchart illustrating the detailed operation of blockchain-based node authentication as depicted in step S1710 of FIG. 17. The present embodiment provides a method for securely verifying the identity of a node in a satellite network environment by utilizing distributed ledger technology.

[0429] Referring to FIG. 18, in step S1810, the processor (1510) can obtain a node identifier and an authentication token as input data from an inquiry message received through a communication circuit (1530). The node identifier is information that uniquely identifies the node requesting authentication and may be represented, for example, as a 36-character string in the form of a UUID. The authentication token is a security token that proves the identity of the node and may be, for example, a string configured in the form of a JWT and encoded in base64.

[0430] The processor (1510) can perform initial validation on the input data. Initial validation is a process of verifying whether the format of the input data is correct, whether all required fields are included, and whether the integrity of the data is maintained. For example, the processor (1510) can verify the integrity of the authentication token using a SHA-256 hash function. If it is confirmed that the token has not been tampered with, the process can proceed to a subsequent authentication process. This initial validation is performed in accordance with the 3GPP Rel-19 TN-NTN integration requirements and can ensure the reliability of subsequent processing.

[0431] In step S1820, the processor (1510) can perform consensus verification. In this embodiment, a Proof of Authority (PoA) consensus mechanism may be used. PoA is a consensus algorithm in which only pre-authorized validator nodes can participate in block creation, and it can provide high processing speed and energy efficiency.

[0432] The processor (1510) can process block generation through multiple validator nodes (e.g., 5 to 10). The validator nodes are trusted entities that have been authorized in advance, and each node can independently verify authentication requests. Consensus among validator nodes can be achieved, for example, through a Raft-based consensus algorithm. The Raft algorithm is an algorithm that ensures consistency in a distributed system through leader election and log replication.

[0433] In this embodiment, the verification time can be maintained within a certain range (e.g., 50 to 100 ms). This can be achieved by keeping the block generation time short (e.g., 1 second). The fast verification time can satisfy the requirements of a real-time location management service.

[0434] In addition, in this embodiment, the low-power terminal communication technology possessed by the present invention can be extended and applied using an off-chain computation method. Off-chain computation is a method of performing computations outside the blockchain and recording only the results on the blockchain, which can reduce the computational load of the blockchain and decrease energy consumption. For example, by performing complex hash operations or signature verification off-chain, energy consumption can be reduced by a certain percentage (e.g., 25%). This is a method that can secure energy efficiency while achieving the level of distributed authentication required by 3GPP Rel-19 SA3 security integration.

[0435] Communication between validator nodes can be performed using low-latency protocols. For example, a protocol combining User Datagram Protocol (UDP) and Quality of Service (QoS) mechanisms can be used. UDP offers low latency due to the absence of a connection establishment process, and the QoS mechanism allows for high priority to be assigned to important authentication messages.

[0436] In step S1830, the processor (1510) may apply a hash function to the input data and the consensus result. Specifically, the processor (1510) may use the SHA-256 hash function to generate a hash value of 256 bits in length. The hash value serves as a unique fingerprint of the input data and can be used to verify the integrity of the data.

[0437] A salt may be added during the hash function application process. The salt is a random value added to the input of the hash function, for example, a random value of 128 bits in length may be used. The addition of a salt can prevent rainbow table attacks. Since a rainbow table attack is an attack method that traces back original data using a database of pre-calculated hash values, adding a random salt can effectively block such attacks.

[0438] The processor (1510) can compare the generated hash value with a reference hash value that is previously stored in memory (1520). The reference hash value is a hash value generated from information of a previously authenticated node and may be recorded in a blockchain. By comparing the hash values, it can be determined whether the current authentication request is valid.

[0439] This hash function application process is performed in accordance with the 3GPP Rel-19 NTN security framework, and the hash collision probability can be kept at an extremely low level (e.g., less than 2^-128). The hash function processing time can be limited to a certain range (e.g., 5 to 10 ms).

[0440] In step S1840, the processor (1510) may perform a branching decision to determine whether authentication is successful. Specifically, the processor (1510) may check whether the hash value generated in step S1830 matches the reference hash value, and whether blockchain consensus was reached in step S1820. For example, if the hash values ​​match (hash_match) and consensus is reached (consensus_reached), it may be determined that authentication is successful.

[0441] These logical operations can be performed within a certain time (e.g., 10ms), which can satisfy the requirements of real-time services. In addition, it can comply with the error tolerance (e.g., less than 1%) required by the 3GPP Rel-19 RRM.

[0442] If authentication fails, the processor (1510) may record an audit log. The log may include information such as a timestamp, a node identifier, the cause of failure, and a severity level. The severity level may be expressed as an integer value from 1 to 5, and may be used by a security manager to analyze the log to identify intrusion attempts or system vulnerabilities.

[0443] If, as a result of the judgment in step S1840, authentication is successful (Yes), the processor (1510) may perform a key exchange in step S1850. The key exchange is a process of establishing a secure session for subsequent communication. In one embodiment, a Diffie-Hellman key exchange algorithm may be used. The Diffie-Hellman algorithm is a cryptographic protocol that enables two parties to securely generate a shared key over a public channel.

[0444] The processor (1510) can generate a shared key through key exchange. The shared key may be, for example, a symmetric key of 256 bits in length and may be used as an encryption key for subsequent data transmission. Ephemeral keys may be used in the key exchange process. Ephemeral keys are keys newly generated for each session, which can provide forward secrecy. Forward secrecy is a security property that prevents data from past sessions from being decrypted even if the long-term key is exposed.

[0445] In this embodiment, the multipath fading compensation technology possessed by the present invention can be applied to signal stabilization during the key exchange process. In a satellite network environment, data transmission errors may occur due to signal fading, which can cause critical problems during the key exchange process. In this embodiment, by applying the multipath fading compensation technology, signal quality can be improved and transmission errors can be attenuated to a certain level (e.g., 10 dB). This allows for an increased success rate of key exchange and enables the stable establishment of a secure session.

[0446] When the key exchange is completed, the processor (1510) can securely store the generated shared key in memory (1520). The shared key is used for subsequent encrypted communication and can satisfy the key management requirements of the 3GPP Rel-19 TN-NTN integration.

[0447] On the other hand, if authentication fails (No) as a result of the judgment in step S1840, the processor (1510) can handle an access denial error in step S1860. The processor (1510) can generate an error message and transmit it to the request node through the communication circuit (1530). The error message may include an error code, a cause of failure, a retry policy, etc.

[0448] For example, error codes can follow standard HTTP status code formats, such as "403 Forbidden". The cause of failure may include specific reasons such as "hash mismatch", "failure to reach consensus", or "token expiration".

[0449] The retry policy can propose an exponential backoff method. For example, it can be proposed that the first retry be performed after 1 second, the second after 2 seconds, and the third after 4 seconds, and the maximum waiting time can be limited to 10 seconds. This can distribute the load on the system and improve stability.

[0450] The processor (1510) can record a detailed log when an error occurs. The log may include information such as a timestamp, node identifier, error type, and severity level. This log information can be used by a system administrator to analyze security threats and establish response measures. The error reporting method may follow the format required by the 3GPP Rel-19 RRM standard.

[0451] The blockchain-based node authentication method of Fig. 18 described above can provide a high level of security in a satellite network environment by combining distributed ledger technology and strong cryptographic verification, and can contribute to the necessary areas for the development of 3GPP Rel-19 NTN security technology.

[0452] FIG. 19 is a flowchart illustrating a Regenerative Payload linked Inter-Satellite Link (ISL) optimization method. This embodiment can be performed by a processor of an Earth ground station (121) or a satellite (110) and provides a method for efficiently setting a data transmission path in a satellite network environment.

[0453] Referring to FIG. 19, in step S1910, the processor can identify the starting terminal and the destination terminal for data transmission. The starting terminal is the terminal that intends to transmit data, and the destination terminal is the terminal that will receive data. The processor can identify the terminals based on the identification information of each terminal. For example, the terminal identifier may be unique identification information such as IMSI (International Mobile Subscriber Identity) and may be expressed in a string format.

[0454] Additionally, the processor can check information about the satellite that each terminal is currently connected to. The satellite information may include a satellite identifier, connection status, signal quality, etc. The satellite identifier may be represented, for example, as a 32-bit integer, and the connection status may be represented as an enumeration value such as connected or idle.

[0455] The processor can perform ID mapping based on the received information. ID mapping is a process of converting terminal identifiers into an internal data structure, for example, a hash table lookup method may be used. The mapping result may be stored in an internal data structure such as an array or a list.

[0456] This terminal identification process is performed in accordance with 3GPP Rel-19 NTN RRM requirements, and can guarantee a high level of terminal identification accuracy (e.g., 99% or higher). In addition, in this embodiment, energy consumption during the identification process can be reduced by applying the low-power terminal communication technology possessed by the present invention. For example, energy consumption can be reduced by a certain percentage (e.g., 20%) by using efficient data structures and algorithms.

[0457] In step S1920, the processor may determine multiple candidate ISL paths to connect the origin satellite and the destination satellite. An Inter-Satellite Link (ISL) is a direct communication link between satellites that allows data to be transmitted between satellites without passing through a ground station. ISLs can be classified into In-plane ISLs and Cross-plane ISLs. An In-plane ISL is a link between satellites within the same orbital plane, while a Cross-plane ISL is a link between satellites in different orbital planes.

[0458] The processor can generate candidate paths using a graph algorithm. In one embodiment, a shortest path algorithm, such as the Dijkstra algorithm, may be used. The algorithm may model the satellite network as a graph, representing each satellite as a node and each ISL as an edge. A cost function may be assigned to each edge, and the cost function may include distance and load. For example, the cost may be set lower as the distance increases and the load decreases.

[0459] The processor can generate multiple candidate paths (e.g., 5 to 10) by executing a graph algorithm. The candidate paths represent different paths from a starting satellite to a destination satellite, and each path can be represented by a list of identifiers of the satellites it passes through.

[0460] This embodiment can ensure path diversity based on the 3GPP Rel-19 NTN payload architecture. For example, by securing at least two independent paths, data can be transmitted through another path even if one path fails. The path calculation time can be limited to within a certain range (e.g., 20ms), which can satisfy the requirements of real-time services.

[0461] In addition, in this embodiment, the multipath fading compensation technology possessed by the present invention can be applied to path stability evaluation. The processor can evaluate the signal quality for each candidate path, for example, by measuring the Received Signal Strength Indicator (RSSI) value. By applying the multipath fading compensation technology, signal quality degradation caused by fading can be compensated for, and a path capable of stable communication can be selected. In one embodiment, only paths with an RSSI value of a certain level (e.g., -80 dBm) or higher can be maintained as candidates.

[0462] In step S1930, the processor can minimize the use of Cross-plane ISL by applying fading compensation. Signal fading may occur due to the high-speed movement of satellites, and the fading problem can be particularly severe in the case of Cross-plane ISL because the relative speed between satellites is large.

[0463] The processor can improve signal strength by applying adaptive beamforming technology. Adaptive beamforming is a technique that forms a beam in a specific direction by adjusting the phase and amplitude of the signal generated from each element of an antenna array. For example, beamforming can be performed using a phase shift array composed of 16 antenna elements. This allows signal strength to be improved by a certain level (e.g., 10 dB) and the RSSI value to be maintained above a certain level (e.g., -80 dBm).

[0464] Additionally, the processor may apply a penalty factor to the Cross-plane ISL. The penalty factor is a weight that increases the cost of a path using the Cross-plane ISL, and a real value such as 2.0 may be used. By applying the penalty factor, path selection can be encouraged to prioritize the use of the In-plane ISL. Additionally, the number of Cross-plane ISLs included in the path can be limited (e.g., fewer than 3).

[0465] In this embodiment, the multipath fading compensation technology possessed by the present invention is applied as a core element to achieve a fading compensation rate at a high level (e.g., 90% or more). This can provide the effect of enhancing signal stability required by the 3GPP Rel-19 NTN RRM.

[0466] In step S1940, the processor can calculate the delay time occurring in the regenerative payload. The regenerative payload is a gNB (next generation NodeB) mounted on the satellite, which can perform packet processing functions such as demodulating and remodulating received data for transmission.

[0467] The processor can calculate packet processing time. The said packet processing time may include the time required for processes such as demodulation, decoding, routing, encoding, and modulation. In one embodiment, packet processing may be analyzed using a queuing model. For example, an M / M / 1 queuing model may be applied, which is a model that assumes packet arrival following a Poisson distribution and service time following an exponential distribution.

[0468] The processor may apply a latency calculation formula. The formula may include propagation delay, processing time, and queuing delay. Propagation delay is the time it takes for a signal to travel between satellites and can be calculated by dividing the distance by the speed of light (e.g., 3 × 10^8 m / s). Processing time is the time it takes to process a packet in a regenerative payload, and a fixed value of, for example, 5 ms may be used. Queuing delay is the time a packet waits in a queue and may vary depending on the queue size, packet arrival rate, service speed, etc.

[0469] In this embodiment, energy consumption during the packet processing process can be optimized by applying the low-power terminal communication technology possessed by the present invention. For example, it is possible to provide the necessary processing performance while maintaining the power consumption of the regenerative payload below a certain level (e.g., 1W). The delay calculation time can be limited to within a certain range (e.g., 10ms).

[0470] This delay calculation method is performed according to the 3GPP Rel-19 RAN4 CR on payload architecture and can comply with delay optimization algorithms.

[0471] In step S1950, the processor may select an optimal path and transmit a path setting message. The processor may select the optimal path from among multiple candidate paths by applying selection criteria. The selection criteria may include minimizing latency and maximizing signal quality.

[0472] In one embodiment, the processor may evaluate each path using a score function. The score function may be a formula that combines latency and signal quality as weights. For example, a method may be used in which a high weight is assigned to the inverse of latency and a relatively low weight is assigned to the RSSI value. The processor may calculate the score function and select the path with the highest score as the optimal path.

[0473] The processor may generate a message containing selected optimal path information. The message may include information such as a list of identifiers for the selected ISL path, an estimated delay time, and an estimated signal quality. The list of path identifiers may be represented as an integer array listing the identifiers of the satellites to be traversed in order. The estimated delay time may be represented as a real value in milliseconds (ms) and may have a certain precision (e.g., 0.1ms).

[0474] The processor can perform Quality of Service (QoS) mapping in accordance with the 3GPP Rel-19 RRM. QoS mapping is the process of setting priorities for data traffic, and, for example, a priority queue can be used to assign high priority to important traffic. This allows latency to be maintained below a certain level (e.g., 30ms).

[0475] The processor can transmit the generated message to the access satellite through a communication circuit. During the message transmission process, the low-power terminal communication technology possessed by the present invention can be applied to reduce transmission energy by a certain percentage (e.g., 15%).

[0476] The Regenerative Payload-linked ISL optimization method of Fig. 19 described above can contribute to the introduction of the 3GPP Rel-19 regenerative payload and reduce end-to-end latency by a certain percentage (e.g., 15%). In addition, this method can provide communication quality suitable for new applications such as the Urban Air Mobility (UAM) and marine communication markets.

[0477] FIG. 20 is a block diagram showing an extended hardware configuration (2000) of a location management device (127). This embodiment provides a hardware configuration for safely and efficiently processing terminal location information in a satellite network environment, and in particular proposes a dual security architecture that maximizes energy efficiency when performing security functions of a terminal or satellite payload operating in a low-power environment.

[0478] Referring to FIG. 20, the extended hardware configuration (2000) may include a processor (2005), a security coprocessor (2010), an encryption information storage unit (2015), a communication circuit (2020), and a low-power encryption module (2025).

[0479] The processor (2005) is a central processing unit that controls the overall operation of the location management device. The processor (2005) can perform various functions such as receiving inquiry messages, querying location data, executing machine learning models, and processing authentication. In one embodiment, the processor (2005) can support multitasking. Multitasking is the ability to process multiple tasks simultaneously, for example, by using a thread pool so that multiple threads can be executed in parallel. This allows real-time location prediction and authentication processes to be performed simultaneously, and can improve the processing efficiency of the system.

[0480] The processor (2005) can operate in accordance with 3GPP Rel-19 NTN-IoT RRM requirements and can meet the specific requirements of a satellite network environment. In this embodiment, the low-power terminal communication technology possessed by the present invention can be applied to the operation of the processor. For example, the processor (2005) can dynamically adjust the operating frequency using a clock downscaling technique. By lowering the frequency when the load is low and raising the frequency when the load is high, energy consumption can be reduced by a certain percentage (e.g., 20%). The operating frequency can be dynamically adjusted, for example, between 1.5 GHz and 2.5 GHz.

[0481] The processor (2005) is connected to other hardware components. Specifically, the processor (2005) is connected to a security coprocessor (2010), an encryption information storage unit (2015), a communication circuit (2020), and a low-power encryption module (2025), respectively, and can coordinate data transmission and control signal transmission between them.

[0482] The security coprocessor (2010) is an auxiliary processor dedicated to security-related operations. In one embodiment, the security coprocessor (2010) may conform to the Trusted Platform Module (TPM) 2.0 specification. The TPM is a hardware-based security module that can provide security functions such as encryption key generation, key storage, digital signatures, and authentication. The security coprocessor (2010) provides a hardware-based root of trust to verify the integrity of the firmware during the secure boot sequence by comparing SHA-256 hash values. Additionally, it securely generates and manages encryption keys, such as RSA-2048 bits, in internal protected memory and processes standard encryption operations (e.g., AES, RSA) at high speed through hardware acceleration. The processor (2005) improves the overall performance of the system by offloading these security functions through the security interface (2010a). The above security interface (2010a) can support a high data transfer speed of 16 GT / s in accordance with the PCIe (Peripheral Component Interconnect Express) 4.0 standard.

[0483] The security coprocessor (2010) can perform key management functions. For example, it can securely store and manage 2048-bit keys of the RSA algorithm. The keys are stored in a protected memory area inside the security coprocessor and can be protected so that they cannot be directly accessed from the outside.

[0484] Additionally, the security coprocessor (2010) can perform authentication token processing. It can receive the authentication token as input, verify it, and transmit the verification result to the processor (2005). In one embodiment, the security coprocessor (2010) can provide a hardware-based root of trust. The root of trust is a security mechanism that verifies the integrity of the firmware during system booting and can perform a secure boot sequence. For example, during the booting process, the SHA-256 hash value of the firmware can be calculated and compared with a previously stored reference hash value to confirm that the firmware has not been tampered with.

[0485] These security features are provided in accordance with 3GPP Rel-19 TN-NTN integration requirements and can ensure a high level of security in a satellite network environment.

[0486] The processor (2005) and the security coprocessor (2010) can be connected via a security interface (2010a). In one embodiment, the security interface may conform to the PCIe (Peripheral Component Interconnect Express) 4.0 standard. PCIe 4.0 provides high data transfer speeds (e.g., 16 GT / s) and can support fast data exchange between the processor and the security coprocessor.

[0487] The encrypted information storage unit (2015) is a part of the memory (1520) and is a storage device that stores sensitive information, such as location table data or logs, by encrypting it. In one embodiment, the storage unit (2015) may be implemented as an NVMe SED (NVM Express Self-Encrypting Drive) that automatically encrypts data at the hardware level. The stored data is encrypted with a strong algorithm such as AES-256-CBC. In particular, the signal correction principle of the multipath fading compensation technology possessed by the present invention is extended and applied to storage access stabilization, thereby minimizing the data read / write error rate to less than 10^-6 through an enhanced error correction code (ECC). The processor (2005) accesses the storage unit (2015) through an encrypted memory interface (2015a), and the interface provides a high throughput of 4 GB / s to prevent data leakage and eavesdropping.

[0488] The encryption information storage unit (2015) can receive location-related information as input. The location-related information may include a terminal identifier, a satellite identifier, a tracking area code, geographical coordinates, a timestamp, etc. The encryption information storage unit (2015) can apply AES-256 encryption to the received data. AES-256 is a symmetric key encryption algorithm that uses a 256-bit key and can provide a high level of security. The CBC (Cipher Block Chaining) mode may be used as the encryption operation mode, and the block size may be 128 bits.

[0489] In this embodiment, the multipath fading compensation technology possessed by the present invention can be extended and applied to storage access stabilization. In a satellite network environment, errors may occur during storage access due to external factors such as vibration, temperature changes, and radiation. In this embodiment, the signal correction principle of the multipath fading compensation technology can be applied to storage access to strengthen the Error Correction Code (ECC). For example, by adding parity bits, the data read / write error rate can be minimized to an extremely low level (e.g., less than 10^-6).

[0490] This data protection method can meet the data-at-rest protection level required by 3GPP Rel-19 SA3 security integration.

[0491] The processor (2005) and the encrypted information storage unit (2015) can be connected via an encrypted memory interface (2015a). In one embodiment, the interface can be implemented as an encrypted NVMe interface and can provide high throughput (e.g., 4 GB / s). By applying encryption during the data transmission process, data leakage or eavesdropping through the interface can be prevented.

[0492] The communication circuit (2020) is responsible for communication with an external network and may include a 5G NR modem, a Wi-Fi module, or an RF transceiver for satellite communication. In particular, the communication circuit (2020) may include a blockchain interface (2020a) for interoperability with a blockchain network. The interface (2020a) supports Ethereum APIs, etc., and supports distributed authentication, in which multiple nodes cooperate to perform authentication without a central server. In addition, it optimizes smart contract calls and manages network latency to less than 200ms, thereby satisfying the 3GPP Rel-19 TN-NTN integration requirements.

[0493] The blockchain interface (2020a) can support distributed authentication. Distributed authentication is a method in which multiple nodes cooperate to perform authentication without a central server, which can eliminate a single point of failure and improve the reliability of the system.

[0494] The blockchain interface (2020a) can receive and process node queries as input. A node query is a request for information about the blockchain network, and can, for example, query the authentication status or transaction history of a specific node. The blockchain interface (2020a) can optimize smart contract calls. To efficiently manage the computational costs incurred during smart contract execution, the interface can monitor execution time and resource usage. This prevents excessive resource consumption caused by malicious code or infinite loops and improves the stability of the system.

[0495] Additionally, the blockchain interface (2020a) can manage network latency. Since the blockchain network is a distributed system, latency may occur, and the interface can be optimized to keep the latency below a certain level (e.g., 200ms). This can satisfy the 3GPP Rel-19 TN-NTN integration requirements.

[0496] The processor (2005) and the communication circuit (2020) can be connected via an API interface (2020b). In one embodiment, the interface may be implemented based on Ethernet and may provide a high communication speed (e.g., 10 Gbps). This ensures stable interoperability between the processor and the blockchain network.

[0497] The low-power encryption module (2025) is a dedicated hardware module that performs encryption operations with low power. Apart from the security coprocessor (2010), in this embodiment, low-power terminal communication technology can be extended and applied to ECC (Elliptic Curve Cryptography). ECC is a public-key encryption method based on elliptic curve mathematics, and can provide an equivalent level of security with a shorter key length compared to RSA, thereby reducing computational load and energy consumption.

[0498] The low-power encryption module (2025) can perform elliptic curve cipher operations (e.g., secp256r1 curve-based ECDSA) that provide an equivalent level of security with a key length shorter than RSA. secp256r1 is a standard elliptic curve with a 256-bit key length and is a curve recommended by NIST (National Institute of Standards and Technology).

[0499] The low-power encryption module (2025) can perform key generation and signature generation functions. Key generation is the process of generating a public key and a private key pair, and signature generation is the process of adding a digital signature to data using the private key. In one embodiment, the Elliptic Curve Digital Signature Algorithm (ECDSA) may be used.

[0500] The low-power encryption module (2025) can receive location data as input and perform encryption. The encryption process can be operated in low-power mode. In low-power mode, the idle current of the module can be maintained at an extremely low level (e.g., less than 1 mA). This allows the battery life of the NTN-IoT terminal to be extended by a certain percentage (e.g., 30%). This can meet the low-power operation level required by the 3GPP Rel-19 NTN security framework.

[0501] Depending on the type of data or the power state of the system, the processor (2005) may use a low-power encryption module (2025) through a low-power interface (2025a) or optionally utilize a security coprocessor (2010). The low-power interface (2025a) may be implemented as an ECC bus for efficient key exchange. For example, a shared key can be securely exchanged between two modules using a Diffie-Hellman variant algorithm.

[0502] The extended hardware configuration of FIG. 20 described above can significantly improve the security and energy efficiency of a location management device in a satellite network environment. Specifically, the extended hardware configuration of FIG. 20 significantly improves the security and energy efficiency of a location management device in a satellite network environment through a dual security architecture that selectively uses a standard encryption processor when high security is required and a low-power encryption module in a limited-power environment. In particular, by applying the multipath fading compensation technology and low-power terminal communication technology possessed by the present invention at the hardware level, stable and efficient location information management is enabled. Furthermore, this configuration can contribute to 3GPP Rel-19 SA2 CR on hardware extensions and can provide a foundation for future development into 6G systems.

[0503] FIG. 21 is a block diagram showing the satellite network architecture (2100) and the main interfaces between each component. This figure shows how satellites, ground stations, terminals, and core network functions are organically interconnected to provide end-to-end communication services.

[0504] Referring to FIG. 21, the NTN system architecture (2100) may include a satellite (2110), another satellite (2120), an earth ground station (2130), a terminal (2140), an HLNR (2150), a mobile network operator system (2160), and a Constellation management system (2170).

[0505] The satellite (2110) may include a regenerative payload block. The regenerative payload is an onboard processing function mounted on the satellite that can perform some or all of the functions of a gNB DU (Distributed Unit). In one embodiment, the gNB DU can perform physical layer processing, MAC (Medium Access Control) layer processing, RLC (Radio Link Control) layer processing, etc. This is the core communication processing part of the satellite and performs some of the base station functions, such as a 3GPP-based gNB-DU (gNodeB-Distributed Unit). Through this, the satellite can perform active processing to demodulate, decode, route, and remodulate received data, going beyond simple signal relay (bent-pipe). The use of a regenerative payload improves the signal-to-noise ratio (SNR) and enables direct data transmission over satellite-to-satellite links, thereby significantly improving the efficiency of the entire system.

[0506] The satellite (2110) can perform packet processing. The packet processing may include a series of processes for demodulating, decoding, routing, encoding, and modulating received data packets. The packet processing process may be managed using a queuing model. In one embodiment, an M / M / 1 queuing model may be applied, and the size of the queue may store, for example, 1024 packets. The service rate may process, for example, 5000 packets per second.

[0507] The satellite (2110) can communicate with the terminal (2140) via a service link (2113). The service link is a wireless communication link between the satellite and the ground terminal, and, for example, the cellular band B71 may be used. The uplink (UL) of the B71 band may use a frequency range of 663-698 MHz, and the downlink (DL) may use a frequency range of 617-652 MHz. The satellite (2110) can receive data from the terminal (2140) via the service link (2113). The data may be transmitted in the form of an IP (Internet Protocol) packet, and the maximum size of each packet may be, for example, 1500 bytes.

[0508] In this embodiment, signal correction can be performed by applying the multipath fading compensation technology possessed by the present invention. In communication between a satellite and a terminal, problems such as the Doppler effect, path loss, and fading may occur, and these problems can be mitigated through the multipath fading compensation technology. For example, communication quality can be improved by maintaining the Error Vector Magnitude (EVM) below a certain level (e.g., 3%) and improving the Signal-to-Noise Ratio (SNR) to a certain level (e.g., 12dB) or higher.

[0509] The satellite (2110) can transmit the processed data via an Inter-Satellite Link (ISL) (2111) or a feeder link (2112). An ISL is a direct communication link between satellites, and a feeder link is a communication link between a satellite and a ground station on Earth. An appropriate link may be selected depending on the destination of the data.

[0510] The satellite (2110) can operate according to the 3GPP Rel-19 NTN payload architecture. In particular, energy efficiency can be optimized by reflecting a change request (CR) regarding the regenerative mode. For example, power consumption per beam can be kept below a certain level (e.g., 50W).

[0511] Additionally, the satellite (2110) can support AI / ML-based traffic prediction as required by 3GPP Rel-20 6G TR 22.837. The processor can predict traffic patterns using a pre-trained machine learning model and maintain a high level of prediction accuracy (e.g., over 90%). This allows for the efficient allocation of network resources and the prevention of congestion in advance.

[0512] Reference numeral 2120 indicates another satellite (Cross / In-plane connection). This refers to an adjacent satellite located in the same orbital plane (in-plane) or a different orbital plane (cross-plane), and said other satellite may be connected to the satellite (2110) via an ISL module (2111). The ISL module (2111) is a hardware module for inter-satellite communication and, in one embodiment, may be implemented as an optical laser transceiver. Optical laser communication can provide high bandwidth (e.g., 100 Gbps) and low interference. The wavelength used may be, for example, 1550 nm.

[0513] ISL can be classified into Cross-plane ISL and In-plane ISL. Cross-plane ISL is a link between satellites in different orbital planes, and In-plane ISL is a link between satellites within the same orbital plane. The ISL module (2111) can handle both types of connections. The ISL module (2111) represents an ISL (Inter-Satellite Link) Optical Link. This enables high-speed optical communication of 100 Gbps with other satellites (2120), supporting direct data transmission and handover between satellites. The ISL module (2111) can use laser-based Free-Space Optical Communication technology, which can provide much higher bandwidth and lower interference compared to RF-based communication. Since this inter-satellite communication does not go through an Earth ground station, communication delay can be significantly reduced, and it plays a key role in ensuring service continuity, especially in regions lacking ground infrastructure, such as polar regions or oceans.

[0514] The ISL module (2111) can receive packets as input from the satellite (2110). Adaptive coding techniques may be applied for link stabilization. For example, Forward Error Correction (FEC) code may be used, and the coding rate may be set to 1 / 2. This means that half of the transmitted data is redundancy for error correction.

[0515] The ISL module (2111) can form a multi-hop path. Multi-hop means that data is transmitted via multiple satellites, and the maximum number of hops can be limited to, for example, 3 hops. This is to prevent an increase in latency.

[0516] According to 3GPP Rel-19 NTN RRM, the ISL module (2111) can ensure latency minimization. Latency per hop can be maintained at, for example, less than 10ms. This allows the overall end-to-end latency to be kept low.

[0517] Reference number 2112 represents a feeder link, which is a communication path between a satellite (2110) and an Earth ground station / gateway processor (2130). This link primarily uses Ka-band frequencies (uplink 27.5-30 GHz, downlink 17.7-20.2 GHz) to transmit large amounts of data uplink (UL) and downlink (DL). The feeder link serves as a backhaul between the satellite and the core network and is designed to provide high data throughput.

[0518] Reference number 2113 represents a Service Link, which is a path through which a satellite (2110) provides direct communication services to an end-user terminal (UE, 2140). In this embodiment, the cellular frequency band Band 71 (downlink 617-652 MHz, uplink 663-698 MHz) is used as an example, allowing commercial terminals such as standard smartphones to use satellite communication without separate special equipment. This enables seamless integration between the terrestrial cellular network and the satellite network, thereby providing the user with a seamless service experience.

[0519] The Earth ground station (2130) may include a gateway processor. The gateway processor is a processing unit responsible for data conversion and routing between the satellite and the ground network. It receives and processes satellite signals and performs the role of connecting to the ground internet network. The gateway (2130) converts data received from the satellite via the feeder link (2112) into a ground network protocol and connects to the HLNR (2150) and other network elements via a wired interface (2114), for example, Ethernet.

[0520] The Earth ground station (2130) can receive data from the satellite (2110) via a feeder link (2112). The feeder link may use the Ka band, with the uplink using a frequency range of 27.5–30 GHz and the downlink using a frequency range of 17.8–20.2 GHz. The Ka band provides high bandwidth but may be affected by rain attenuation.

[0521] The gateway processor can process satellite data as input. The data may be encrypted packets, for example, AES-256 encryption may be applied. The gateway processor can decrypt the encrypted data and perform necessary protocol conversions.

[0522] In this embodiment, the low-power terminal communication technology possessed by the present invention can be applied to the energy efficiency optimization of the gateway processor. For example, by using an efficient packet processing algorithm and a power management technique, power consumption per gateway can be maintained below a certain level (e.g., 100W).

[0523] The gateway processor can transmit the processed data to the HLNR (2150) via a wired interface. The wired interface can be implemented, for example, as Ethernet and can provide a high communication speed (e.g., 10 Gbps). Virtual LAN (VLAN) tagging can be applied for network isolation.

[0524] Additionally, the ground station (2130) can support handover signaling in accordance with 3GPP Rel-19 TN-NTN integration. Handover is the process of maintaining a connection when a terminal moves from a cell of one base station to a cell of another base station. The ground station can relay handover signaling between base stations through the Xn interface.

[0525] Reference number 2140 represents a User Equipment (UE). This is a device used by an end user for satellite communication services and may include various forms such as smartphones, tablets, vehicle terminals, and IoT sensors. The terminal (2140) communicates directly with the satellite (2110) through a service link (2113).

[0526] The HLNR (2150) may include a location management server. The HLNR is a database system that manages the terminal's location information and the current serving network type in a hybrid network environment where non-terrestrial and terrestrial networks coexist. The HLNR (2150) manages the terminal's location information in a hybrid network environment where satellite and terrestrial networks coexist, and performs intelligent functions such as mobility prediction, discontinuous coverage processing, and handover optimization. The HLNR (2150) receives data from the gateway (2130) through a wired interface (2114) and is connected to the core network of a mobile network operator (MNO, 2160) through a data network (2115), such as a secure channel like an IPsec (IP Security) tunnel. Additionally, the HLNR (2150) can perform the function of mutual conversion and provision of location information between operators when necessary.

[0527] HLNR (2150) can manage a location-network table (1521). The table has a database schema and can use a terminal identifier as the primary key. The location field can be represented, for example, in a 64-bit floating-point format. The table can store not only the terminal's current location but also the type of network the terminal is connected to (terrestrial network or non-terrestrial network), serving satellite or base station information, etc.

[0528] HLNR (2150) can receive a query as input from the Earth ground station (2130). The query can be expressed in a SQL-like format, and the maximum number of rows to be retrieved can be limited to, for example, 1000. This is to prevent system load caused by excessive data retrieval.

[0529] HLNR (2150) can predict the location by applying an AI / ML module. In one embodiment, a Long Short-Term Memory (LSTM) or an equivalent time series prediction model may be used. The hidden size of the model may be set to, for example, 256. The AI / ML module can predict the future location by learning the terminal's past movement patterns.

[0530] HLNR (2150) can generate and output the query processing result as a response message. The response message can be expressed in JSON or binary format, and its size can be limited to, for example, less than 2KB.

[0531] HLNR (2150) can perform continuous learning in accordance with the 3GPP Rel-19 AI / ML PHY layer requirements. Continuous learning is a method of continuously updating the model as new data is collected. The batch size can be set to, for example, 64.

[0532] Additionally, HLNR (2150) can support edge AI processing as required by 3GPP Rel-20 6G TR 22.837. Edge AI is a method of performing AI computations at the network edge rather than on a central server, which can significantly reduce latency. For example, the latency of edge AI processing can be kept below 5ms.

[0533] In a hybrid network environment, HLNR (2150) can provide seamless location management services when a terminal switches from a terrestrial network to a non-terrestrial network or vice versa. For example, when a terminal moves out of terrestrial network coverage and switches to a satellite network, HLNR (2150) can update the terminal's location information in real time and record new serving network information.

[0534] The mobile network operator system (2160) represents the system network (135) of the Mobile Network Operator (MNO). The MNO system can be connected to the HLNR (2150) via a data network (2115). Reference numeral 2115 represents a data network, specifically a secure communication channel such as an IPsec tunnel. Through this, sensitive location information and control signals can be securely exchanged between the HLNR (2150) and the MNO (2160). The data network can be configured, for example, as an IPsec tunnel, and the Virtual Private Network (VPN) throughput can be 1 Gbps. IPsec is a protocol suite that provides security at the IP layer and can guarantee the confidentiality, integrity, and authentication of data.

[0535] Reference number 2160 represents a Mobile Network Operator (MNO). Users subscribe to services through the MNO, and the MNO can utilize the satellite network as a means of expanding its coverage through interoperability with HLNR (2150). Through this, the MNO can provide services to customers even in areas where the terrestrial network cannot reach, which can lead to the creation of new revenue streams and improved customer satisfaction.

[0536] The MNO system (2160) can receive location data as input from the HLNR (2150). The data may be encrypted and may have a Time To Live (TTL) value set. For example, the TTL may be set to 60 seconds, which indicates the validity period of the data.

[0537] The MNO system (2160) can perform session management using the 5GC (5G Core). The 5GC is a core network of the 5G network and may include network functions such as the Access and Mobility Management Function (AMF) and the Session Management Function (SMF). The AMF manages the connection and mobility of terminals, and the SMF manages Protocol Data Unit (PDU) sessions. Sessions can be distinguished by PDU session identifiers.

[0538] The MNO system (2160) can route the processed data to a ground base station (134). During the routing process, ground / non-ground interoperability can be ensured in accordance with 3GPP Rel-19 TN-NTN integration. This is to provide seamless service in a hybrid network environment.

[0539] Additionally, the MNO system (2160) can apply Quality of Service mapping. QoS mapping is the process of allocating appropriate priorities and resources to different types of traffic. Priority queues can be used to prioritize important traffic. For example, latency can be kept below a certain level (e.g., 20ms) and jitter below a certain level (e.g., 5ms). Jitter is an indicator of the variability of packet arrival times.

[0540] The Constellation management system (2170) manages orbit and status information of the satellite (2110) and other satellites (2120) in real time, provides the latest topology information to the HLNR (2150), receives optimal path information calculated from the HLNR (2150), and commands routing settings to the satellites.

[0541] The telemetry and command transmission interface (2171) is a connection link between the Earth ground station (2130) and the Constellation management system (2170), and is used as a path to transmit status information (Telemetry) received from the satellite (2110) from the Earth ground station (2130) to the management system (2170), or conversely, to transmit satellite control commands generated by the management system (2170) to the satellite (2110) through the Earth ground station (2130).

[0542] The Ephemeris infor...

Claims

1. A location management device configured to register and manage location-related information for each terminal, Memory for storing instructions; At least one processor; and Includes a communication circuit, When the above instructions are executed by the at least one processor, the position management device: Through the above communication circuit, an inquiry message requesting the location of the terminal is received through the above communication circuit, and In response to the above inquiry message, determine whether a table configured to store terminal-specific location-related information in the memory includes location-related information of the terminal, and Based on the determination that the above table includes location-related information of the terminal, a response message including location-related information of the terminal is transmitted to the node that transmitted the inquiry message through the communication circuit, and Based on the determination that the above table does not include location-related information of the above terminal, the node that transmitted the above inquiry message is caused to transmit an error response message through the above communication circuit, and The above table is used to store location-related information of a terminal connected to a cell provided by a base station providing a terrestrial network and location-related information of a terminal connected to a cell provided by a satellite providing a non-terrestrial network. Location management device.

2. In Claim 1, The above table includes a list of one or more registered terminals and location-related information for each terminal included in the list, and The above location-related information includes at least one of whether the terminal is connected to a terrestrial network, identification information of the base station providing the cell the terminal is connected to, identification information of the tracking area (TA) associated with the cell the terminal is connected to, whether the terminal is connected to a non-terrestrial network, identification information of the satellite providing the cell the terminal is connected to, or identification information of the operator to which the terminal subscribes. Location management device.

3. In Claim 2, The above inquiry message includes identification information of the terminal and information indicating a request item among the above location-related information, and The above response message includes the query result for the above request item, Location management device.

4. In Claim 1, The above location-related information includes information about the cell that the terminal is connected to, and Information regarding the above cell is used to identify whether the cell provides DTC (direct to cell) communication services provided by the satellite operator's satellite, Location management device.

5. In Claim 1, When the above instructions are executed by the at least one processor, the position management device: If the node that transmitted the above inquiry message is an Earth ground station of a satellite operator, identify the format corresponding to the said satellite operator, and By converting the location-related information of the terminal included in the table according to the above-identified format, converted data is obtained, and Causing a response message containing the above converted data to be transmitted to the earth ground station through the communication circuit, Location management device.

6. In a network entity deployed on the ground and for determining one or more inter-satellite links (ISLs), Memory for storing instructions; At least one processor; and Includes satellite communication circuits, When the above instructions are executed by the above at least one processor, the network entity: Identify the starting terminal and the destination terminal, and When the above-mentioned starting terminal is connected to the first satellite and the above-mentioned destination terminal is connected to the second satellite, at least one candidate ISL path for connecting the first satellite and the second satellite is determined, and each of the at least one candidate ISL path includes one or more ISLs. Determining whether the above at least one candidate ISL path includes an ISL path in which all ISLs have links between satellites in the same orbital plane, and Causing to transmit a message to an access satellite connected to the network entity via the satellite communication circuit, based on a determination that the above-mentioned at least one candidate ISL path includes the above-mentioned ISL path, for establishing a data transmission path according to the above-mentioned ISL path. Network Entity.

7. In Claim 6, When the above instructions are executed by the above at least one processor, the network entity: Based on the determination that the above at least one candidate ISL path does not include the above first type of ISL path, the data transmission path is determined based on the number of ISLs corresponding to links between satellites in different orbital planes, and Causing a message to be transmitted to an access satellite connected to the network entity via the satellite communication circuit to establish the data transmission path according to the above ISL path, Network Entity.

8. In Claim 6, When the above instructions are executed by the above at least one processor, the network entity: If the above-mentioned starting terminal is connected to the first satellite and the above-mentioned destination terminal is connected to the second terrestrial network, determine whether the above-mentioned first satellite is an access satellite connected to the above-mentioned network entity in the satellite frequency band, and Causing to transmit a message through the satellite communication circuit to establish a data transmission path to the first satellite, based on the determination that the first satellite is an access satellite connected to the network entity in the satellite frequency band. Network Entity.

9. In Claim 8, When the above instructions are executed by the above at least one processor, the network entity: Based on the determination that the first satellite is not an access satellite connected to the network entity in the satellite frequency band, at least one candidate ISL path is determined to connect the first satellite and the access satellite, and Causing the access satellite to transmit a message through the satellite communication circuit to establish a data transmission path for one of the at least one candidate ISL paths for connecting the first satellite and the access satellite. Network Entity.

10. In Claim 6, The message for establishing the above data transmission path is transmitted over an E-band having a range of approximately 60 GHz to 95 GHz, Network Entity.

11. A method performed by a location management device configured to register and manage location-related information per terminal, The operation of receiving an inquiry message requesting the location of the terminal, and An operation to determine whether a table configured to store terminal-specific location-related information in response to the above inquiry message includes location-related information of the terminal in the location management device, and An operation of transmitting a response message containing location-related information of the terminal to the node that transmitted the inquiry message, based on a determination that the above table contains location-related information of the terminal, and Based on the determination that the above table does not include location-related information of the terminal, the operation of sending an error response message to the node that sent the inquiry message is included. The above table is used to store location-related information of a terminal connected to a cell provided by a base station providing a terrestrial network and location-related information of a terminal connected to a cell provided by a satellite providing a non-terrestrial network. method.

12. In Claim 11, The above table includes a list of one or more registered terminals and location-related information for each terminal included in the list, and The above location-related information includes at least one of whether the terminal is connected to a terrestrial network, identification information of the base station providing the cell the terminal is connected to, identification information of the tracking area (TA) associated with the cell the terminal is connected to, whether the terminal is connected to a non-terrestrial network, identification information of the satellite providing the cell the terminal is connected to, or identification information of the operator to which the terminal subscribes. method.

13. In Claim 12, The above inquiry message includes identification information of the terminal and information indicating a request item among the above location-related information, and The above response message includes the query result for the above request item, method.

14. In Claim 11, The above location-related information includes information about the cell that the terminal is connected to, and Information regarding the above cell is used to identify whether the cell provides DTC (direct to cell) communication services provided by the satellite operator's satellite, method.

15. In claim 11, the operation of transmitting the response message is: If the node that transmitted the above inquiry message is an Earth ground station of a satellite operator, the operation of identifying a format corresponding to the said satellite operator, and An operation to obtain converted data by converting location-related information of the terminal included in the table according to the above identified format, and The operation of transmitting a response message containing the above converted data to the earth ground station, method.

16. A method performed by a network entity deployed on the ground and for determining one or more inter-satellite links (ISLs), An operation to identify the starting terminal and the destination terminal, and When the starting terminal is connected to the first satellite and the destination terminal is connected to the second satellite, the operation of determining at least one candidate ISL path for connecting the first satellite and the second satellite, and each of the at least one candidate ISL path includes one or more ISLs, and The operation of determining whether the above at least one candidate ISL path includes an ISL path in which all ISLs have links between satellites in the same orbital plane, and The operation of transmitting a message to an access satellite connected to the network entity to establish a data transmission path according to the ISL path, based on a determination that the above-mentioned at least one candidate ISL path includes the above-mentioned ISL path. method.

17. In Claim 16, An operation to determine the data transmission path based on the number of ISLs corresponding to links between satellites of different orbital planes, in accordance with the determination that the above at least one candidate ISL path does not include the above first type of ISL path, and The method further includes the operation of transmitting a message to an access satellite connected to the network entity to establish the data transmission path according to the above ISL path. method.

18. In Claim 16, When the above-mentioned starting terminal is connected to the first satellite and the above-mentioned destination terminal is connected to the second terrestrial network, the operation of determining whether the first satellite is an access satellite connected to the network entity in the satellite frequency band, and The method further includes the operation of transmitting a message to the first satellite to establish a data transmission path, based on the determination that the first satellite is an access satellite connected to the network entity in a satellite frequency band. method.

19. In Claim 18, An operation to determine at least one candidate ISL path for connecting the first satellite and the access satellite based on a determination that the first satellite is not an access satellite connected to the network entity in the satellite frequency band, and The method further includes the operation of transmitting a message to the access satellite to establish a data transmission path for one of the at least one candidate ISL paths for connecting the first satellite and the access satellite. method.

20. In Claim 16, The message for establishing the above data transmission path is transmitted over an E-band having a range of approximately 60 GHz to 95 GHz, method.

Images