Connection management between satellite base stations

Abstract

A method and apparatus for a connection management between satellite base stations, e.g., satellite on-board gNBs, is provided. A first satellite base station transmits an interface setup request message to a second satellite base station. The interface setup request message includes information related to the first satellite base station. A first satellite base station receives a response message from the second satellite base station in response to the interface setup request message. The response message may include interface management information, based on which the first satellite base station can establish multi-hop interface connections with other satellite base stations. The exchange of other information and dynamic updates between satellite base stations in response to changes in the interface management information are also provided.

Description

CONNECTION MANAGEMENT BETWEEN SATELLITE BASE STATIONS

[0001] The present disclosure relates to a connection management between satellite base stations, e.g., satellite on-board gNBs.

[0002] 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.

[0003] 3GPP New Radio (NR) targets a single technical framework addressing all usage scenarios, requirements and deployment scenarios including enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), Ultra-Reliable and Low Latency Communications (URLLC), etc. The NR shall be inherently forward compatible. Further, the NR should be able to use any spectrum band ranging at least up to 100 GHz that may be made available for wireless communications even in a more distant future.

[0004] 6G is the successor to 5G cellular technology. 6G networks will be able to use higher frequencies than 5G networks and provide substantially higher capacity and much lower latency. The 6G technology market is expected to facilitate large improvements in the areas of imaging, presence technology and location awareness. Working in conjunction with Artificial Intelligence (AI), the 6G computational infrastructure will be able to identify the best place for computing to occur. This includes decisions about data storage, processing and sharing.

[0005] Non-Terrestrial Network (NTN) is being studied. The basic idea of NTN is to deliver 5G / NR service via space (satellite) or air (airborne platform). If it is realized as expected, it would be able to deliver the 5G service to those places where it is technically very difficult or cost too much to deliver with terrestrial network. Some examples of those places would be a remote area like deep forest that would be too costly with terrestrial delivery, or far islands or ship that would be technically almost forbidden in terrestrial connection.

[0006] In an aspect, a method is provided. The method comprises transmitting, by a first satellite base station, an interface setup request message to a second satellite base station. The interface setup request message includes information related to the first satellite base station. The method comprises receiving, by the first satellite base station, a response message from the second satellite base station in response to the interface setup request message.

[0007] In another aspect, an apparatus for implementing the above method is provided.

[0008] FIG. 1 shows an example of a communication system to which implementations of the present disclosure are applied.

[0009] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure are applied.

[0010] FIG. 3 shows an example of NG-RAN architecture to which implementations of the present disclosure are applied.

[0011] FIG. 4 shows an example of NTN to which implementations of the present disclosure are applied.

[0012] FIG. 5 shows another example of NTN to which implementations of the present disclosure are applied.

[0013] FIG. 6 shows another example of NTN to which implementations of the present disclosure are applied.

[0014] FIG. 7 shows an example of a method to which implementations of the present disclosure are applied.

[0015] FIGS. 8 to 11 show an example of a procedure for Xn connection management between satellite on-board gNBs to which implementations of the present disclosure are applied.

[0016] The following techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of the multiple access systems include a Code Division Multiple Access (CDMA) system, a Frequency Division Multiple Access (FDMA) system, a Time Division Multiple Access (TDMA) system, an Orthogonal Frequency Division Multiple Access (OFDMA) system, a Single Carrier Frequency Division Multiple Access (SC-FDMA) system, and a Multi Carrier Frequency Division Multiple Access (MC-FDMA) system. CDMA may be embodied through radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be embodied through radio technology such as Global System for Mobile communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data rates for GSM Evolution (EDGE). OFDMA may be embodied through radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is a part of a Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA in Downlink (DL) and SC-FDMA in Uplink (UL). Evolution of 3GPP LTE includes LTE-Advanced (LTE-A), LTE-A Pro, 5G New Radio (NR) and / or 6G.

[0017] For convenience of description, implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.

[0018] For terms and technologies which are not specifically described among the terms of and technologies employed in the present disclosure, the wireless communication standard documents published before the present disclosure may be referenced.

[0019] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, "A or B" in the present disclosure may be interpreted as "A and / or B". For example, "A, B or C" in the present disclosure may mean "only A", "only B", "only C", or "any combination of A, B and C".

[0020] In the present disclosure, slash ( / ) or comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Accordingly, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B or C".

[0021] In the present disclosure, "at least one of A and B" may mean "only A", "only B" or "both A and B". In addition, the expression "at least one of A or B" or "at least one of A and / or B" in the present disclosure may be interpreted as same as "at least one of A and B".

[0022] In addition, in the present disclosure, "at least one of A, B and C" may mean "only A", "only B", "only C", or "any combination of A, B and C". In addition, "at least one of A, B or C" or "at least one of A, B and / or C" may mean "at least one of A, B and C".

[0023] Also, parentheses used in the present disclosure may mean "for example". In detail, when it is shown as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, "control information" in the present disclosure is not limited to "PDCCH", and "PDCCH" may be proposed as an example of "control information". In addition, even when shown as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0024] Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.

[0025] Although not limited thereto, various descriptions, functions, procedures, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein can be applied to various fields requiring wireless communication and / or connection (e.g., 5G) between devices.

[0026] Hereinafter, the present disclosure will be described in more detail with reference to drawings. The same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks, and / or functional blocks unless otherwise indicated.

[0027] FIG. 1 shows an example of a communication system to which implementations of the present disclosure are applied.

[0028] The 5G usage scenarios shown in FIG. 1 are only exemplary, and the technical features of the present disclosure can be applied to other 5G usage scenarios which are not shown in FIG. 1.

[0029] Three main requirement categories for 5G include (1) a category of enhanced Mobile BroadBand (eMBB), (2) a category of massive Machine Type Communication (mMTC), and (3) a category of Ultra-Reliable and Low Latency Communications (URLLC).

[0030] Referring to FIG. 1, the communication system 1 includes wireless devices 100a to 100f, Base Stations (BSs) 200, and a network 300. Although FIG. 1 illustrates a 5G network as an example of the network of the communication system 1, the implementations of the present disclosure are not limited to the 5G system, and can be applied to the future communication system beyond the 5G system.

[0031] The BSs 200 and the network 300 may be implemented as wireless devices and a specific wireless device may operate as a BS / network node with respect to other wireless devices.

[0032] The wireless devices 100a to 100f represent devices performing communication using Radio Access Technology (RAT) (e.g., 5G NR or LTE) and may be referred to as communication / radio / 5G devices. The wireless devices 100a to 100f may include, without being limited to, a robot 100a, vehicles 100b-1 and 100b-2, an eXtended Reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet-of-Things (IoT) device 100f, and an Artificial Intelligence (AI) device / server 400. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may include an Augmented Reality (AR) / Virtual Reality (VR) / Mixed Reality (MR) device and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter.

[0033] In the present disclosure, the wireless devices 100a to 100f may be called User Equipments (UEs). A UE may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), a navigation system, a slate Personal Computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or a financial device), a security device, a weather / environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field.

[0034] The wireless devices 100a to 100f may be connected to the network 300 via the BSs 200. An AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network. Although the wireless devices 100a to 100f may communicate with each other through the BSs 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs 200 / network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., Vehicle-to-Vehicle (V2V) / Vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0035] Wireless communication / connections 150a, 150b and 150c may be established between the wireless devices 100a to 100f and / or between wireless device 100a to 100f and BS 200 and / or between BSs 200. Herein, the wireless communication / connections may be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication (or Device-to-Device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, Integrated Access and Backhaul (IAB)), etc. The wireless devices 100a to 100f and the BSs 200 / the wireless devices 100a to 100f may transmit / receive radio signals to / from each other through the wireless communication / connections 150a, 150b and 150c. For example, the wireless communication / connections 150a, 150b and 150c may transmit / receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, and resource mapping / de-mapping), and resource allocating processes, for transmitting / receiving radio signals, may be performed based on the various proposals of the present disclosure.

[0036] NR supports multiples numerologies (and / or multiple Sub-Carrier Spacings (SCS)) to support various 5G services. For example, if SCS is 15 kHz, wide area can be supported in traditional cellular bands, and if SCS is 30 kHz / 60 kHz, dense-urban, lower latency, and wider carrier bandwidth can be supported. If SCS is 60 kHz or higher, bandwidths greater than 24.25 GHz can be supported to overcome phase noise.

[0037] The NR frequency band may be defined as two types of frequency range, i.e., Frequency Range 1 (FR1) and Frequency Range 2 (FR2). The numerical value of the frequency range may be changed. For example, the frequency ranges of the two types (FR1 and FR2) may be as shown in Table 1 below. For ease of explanation, in the frequency ranges used in the NR system, FR1 may mean "sub 6 GHz range", FR2 may mean "above 6 GHz range," and may be referred to as millimeter Wave (mmW).

[0038] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0039] As mentioned above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a frequency band of 410MHz to 7125MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more included in FR1 may include an unlicensed band. Unlicensed bands may be used for a variety of purposes, for example for communication for vehicles (e.g., autonomous driving).

[0040] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0041] Here, the radio communication technologies implemented in the wireless devices in the present disclosure may include NarrowBand IoT (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of Low Power Wide Area Network (LPWAN) technology, may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the above-mentioned names. Additionally and / or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and be called by various names such as enhanced MTC (eMTC). For example, LTE-M technology may be implemented in at least one of the various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and may not be limited to the above-mentioned names. Additionally and / or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN which take into account low-power communication, and may not be limited to the above-mentioned names. For example, ZigBee technology may generate Personal Area Networks (PANs) associated with small / low-power digital communication based on various specifications such as IEEE 802.15.4 and may be called various names.

[0042] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure are applied.

[0043] In FIG. 2, The first wireless device 100 and / or the second wireless device 200 may be implemented in various forms according to use cases / services. For example, {the first wireless device 100 and the second wireless device 200} may correspond to at least one of {the wireless device 100a to 100f and the BS 200}, {the wireless device 100a to 100f and the wireless device 100a to 100f} and / or {the BS 200 and the BS 200} of FIG. 1. The first wireless device 100 and / or the second wireless device 200 may be configured by various elements, devices / parts, and / or modules.

[0044] The first wireless device 100 may include at least one transceiver, such as a transceiver 106, at least one processing chip, such as a processing chip 101, and / or one or more antennas 108.

[0045] The processing chip 101 may include at least one processor, such a processor 102, and at least one memory, such as a memory 104. Additional and / or alternatively, the memory 104 may be placed outside of the processing chip 101.

[0046] The processor 102 may control the memory 104 and / or the transceiver 106 and may be adapted to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts described in the present disclosure. For example, the processor 102 may process information within the memory 104 to generate first information / signals and then transmit radio signals including the first information / signals through the transceiver 106. The processor 102 may receive radio signals including second information / signals through the transceiver 106 and then store information obtained by processing the second information / signals in the memory 104.

[0047] The memory 104 may be operably connectable to the processor 102. The memory 104 may store various types of information and / or instructions. The memory 104 may store a firmware and / or a software code 105 which implements codes, commands, and / or a set of commands that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the firmware and / or the software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the firmware and / or the software code 105 may control the processor 102 to perform one or more protocols. For example, the firmware and / or the software code 105 may control the processor 102 to perform one or more layers of the radio interface protocol.

[0048] Herein, the processor 102 and the memory 104 may be a part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each of the transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be interchangeably used with Radio Frequency (RF) unit(s). In the present disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0049] The second wireless device 200 may include at least one transceiver, such as a transceiver 206, at least one processing chip, such as a processing chip 201, and / or one or more antennas 208.

[0050] The processing chip 201 may include at least one processor, such a processor 202, and at least one memory, such as a memory 204. Additional and / or alternatively, the memory 204 may be placed outside of the processing chip 201.

[0051] The processor 202 may control the memory 204 and / or the transceiver 206 and may be adapted to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts described in the present disclosure. For example, the processor 202 may process information within the memory 204 to generate third information / signals and then transmit radio signals including the third information / signals through the transceiver 206. The processor 202 may receive radio signals including fourth information / signals through the transceiver 106 and then store information obtained by processing the fourth information / signals in the memory 204.

[0052] The memory 204 may be operably connectable to the processor 202. The memory 204 may store various types of information and / or instructions. The memory 204 may store a firmware and / or a software code 205 which implements codes, commands, and / or a set of commands that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the firmware and / or the software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the firmware and / or the software code 205 may control the processor 202 to perform one or more protocols. For example, the firmware and / or the software code 205 may control the processor 202 to perform one or more layers of the radio interface protocol.

[0053] Herein, the processor 202 and the memory 204 may be a part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through one or more antennas 208. Each of the transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be interchangeably used with RF unit. In the present disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0054] Hereinafter, hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as Physical (PHY) layer, Media Access Control (MAC) layer, Radio Link Control (RLC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Resource Control (RRC) layer, and Service Data Adaptation Protocol (SDAP) layer). The one or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs), one or more Service Data Unit (SDUs), messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure.

[0055] The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors 102 and 202. For example, the one or more processors 102 and 202 may be configured by a set of a communication control processor, an Application Processor (AP), an Electronic Control Unit (ECU), a Central Processing Unit (CPU), a Graphic Processing Unit (GPU), and a memory control processor.

[0056] The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. The one or more memories 104 and 204 may be configured by Random Access Memory (RAM), Dynamic RAM (DRAM), Read-Only Memory (ROM), electrically Erasable Programmable Read-Only Memory (EPROM), flash memory, volatile memory, non-volatile memory, hard drive, register, cash memory, computer-readable storage medium, and / or combinations thereof. The one or more memories 104 and 204 may be located at the interior and / or exterior of the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.

[0057] The one or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, to one or more other devices. The one or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, from one or more other devices. For example, the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

[0058] The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208. Additionally and / or alternatively, the one or more transceivers 106 and 206 may include one or more antennas 108 and 208. The one or more transceivers 106 and 206 may be adapted to transmit and receive user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208. In the present disclosure, the one or more antennas 108 and 208 may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).

[0059] The one or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc., from RF band signals into baseband signals in order to process received user data, control information, radio signals / channels, etc., using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals / channels, etc., processed using the one or more processors 102 and 202 from the base band signals into the RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, the one or more transceivers 106 and 206 can up-convert OFDM baseband signals to OFDM signals by their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The one or more transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202.

[0060] Although not shown in FIG. 2, the wireless devices 100 and 200 may further include additional components. The additional components 140 may be variously configured according to types of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power unit / battery, an Input / Output (I / O) device (e.g., audio I / O port, video I / O port), a driving device, and a computing device. The additional components 140 may be coupled to the one or more processors 102 and 202 via various technologies, such as a wired or wireless connection.

[0061] In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.

[0062] FIG. 3 shows an example of NG-RAN architecture to which implementations of the present disclosure are applied.

[0063] An NG-RAN node is either:

[0064] - a gNB, providing NR user plane and control plane protocol terminations towards the UE; or

[0065] - an ng-eNB, providing E-UTRA user plane and control plane protocol terminations towards the UE.

[0066] The gNBs and ng-eNBs are interconnected with each other by means of the Xn interface. The gNBs and ng-eNBs are also connected by means of the NG interfaces to the 5GC, more specifically to the Access and Mobility Management Function (AMF) by means of the NG-C interface and to the User Plane Function (UPF) by means of the NG-U interface.

[0067] A Non-Terrestrial Network (NTN) refers to a network, or segment of networks using RF resources on board a satellite (or Unmanned Aerial System (UAS) platform).

[0068] FIG. 4 shows an example of NTN to which implementations of the present disclosure are applied.

[0069] The NTN provides non-terrestrial NR access to the UE by means of an NTN payload and an NTN Gateway. Referring to FIG. 4, a service link between the NTN payload and a UE, and a feeder link between the NTN gateway and the NTN payload are described.

[0070] In FIG. 4, the NTN payload transparently forwards the radio protocol received from the UE (via the service link) to the NTN gateway (via the feeder link) and vice-versa. The following connectivity is supported by the NTN payload:

[0071] - A NTN gateway may serve multiple NTN payloads;

[0072] - An NTN payload may be served by multiple NTN gateways.

[0073] The NTN payload may change the carrier frequency, before re-transmitting it on the service link, and vice versa (respectively on the feeder link).

[0074] For NTN, the following network identities (IDs) are further applied.

[0075] - A Tracking Area (TA) corresponds to a fixed geographical area. Any respective mapping is configured in the RAN;

[0076] - A mapped cell ID.

[0077] Three types of service links are supported:

[0078] - Earth-fixed: provisioned by beam(s) continuously covering the same geographical areas all the time (e.g., the case of Geosynchronous Orbit (GSO) satellites);

[0079] - Quasi-Earth-fixed: provisioned by beam(s) covering one geographic area for a limited period and a different geographic area during another period (e.g., the case of Non-Geosynchronous Orbit (NGSO) satellites generating steerable beams);

[0080] - Earth-moving: provisioned by beam(s) whose coverage area slides over the Earth surface (e.g., the case of NGSO satellites generating fixed or non-steerable beams).

[0081] With NGSO satellites, the gNB may provide either quasi-Earth-fixed service link or Earth-moving service link, while gNB operating with GSO satellite may provide Earth-fixed service link.

[0082] In FIG.4, the transparent NTN payload which may simply act as an RF relay (with some frequency filtering, conversions, and amplifications) was described.

[0083] Meanwhile, NTN capabilities can be enhanced with the regenerative payload architecture on satellite-based gNBs. Unlike transparent payload, the regenerative payload architecture may additionally require a satellite support gNB functions (e.g., modulation / demodulation, encoding / decoding, switching / routing, management of NG / Xn interfaces and UE contexts, RRM, etc.). With shorter delays over Uu interface and much higher performance capability, the regenerative payload architecture aims to further expand the NTN service capabilities and coverages for more advanced use cases.

[0084] FIG. 5 shows another example of NTN to which implementations of the present disclosure are applied.

[0085] Referring to FIG. 5, a satellite (or UAS platform) implements a regeneration of the signals received from Earth (with on board processing). The satellite (or UAS platform) may typically generate several beams over a given service area bounded by its field of view. The footprints of the beams may be typically of elliptic shape. The field of view of the satellite (or UAS platform) may depend on the on board antenna diagram and min elevation angle.

[0086] Regenerative payload means a payload that transforms and amplifies an uplink RF signal before transmitting it on the downlink. The transformation of the signal refers to digital processing that may include radio frequency filtering, frequency conversion and amplification as well as demodulation / decoding, switch and / or routing, coding / modulation. This may be effectively equivalent to having all or part of base station functions (e.g., gNB) on board the satellite (or UAS platform).

[0087] The regenerative payloads may also optionally provide Inter-Satellite Links (ISL) between satellites in case of a constellation of satellites. ISL is a transport link between satellites. ISL may be a radio interface or an optical interface.

[0088] Satellite Radio Interface (SRI) is on the feeder link between the NTN gateway and the satellite. SRI is a transport link between NTN gateway and satellite.

[0089] The NTN gateway is a transport network layer node, and supports all necessary transport protocols.

[0090] FIG. 6 shows another example of NTN to which implementations of the present disclosure are applied.

[0091] Referring to FIG. 6, Xn connection between one or more gNBs on board a satellite may be established via ISL. The gNB on board different satellites may be connected to the same 5G CN on the ground. If the satellite hosts more than one gNB, the same SRI may transport all the corresponding NG interface instances.

[0092] As mentioned above, as gNB is satellite on-board (e.g., regenerative payload architecture), Xn interface is expected to be supported between satellite on-board gNBs. The ISL may serve as the physical layer medium for Xn connectivity, and for that, there may need to adjust or align satellite antennas for ISL connectivity based on ephemeris of the payloads that have been pre-planned. Operators are highly likely to centrally coordinate and pre-plan ISL connectivity between neighboring satellite on-board gNBs, and determine when ISL connections are established or disconnected.

[0093] However, the management of Xn connections between satellite on-board gNBs cannot always be relied upon manual interventions by operators due to the following reasons.

[0094] (1) Not all satellites are deployed simultaneously. They may be gradually launched over a long scale. Even after achieving a full constellation, additional satellites may be deployed to enhance NTN services. Xn connectivity management may be required between already deployed satellite on-board gNBs and newly launched satellite on-board gNBs. This may allow new satellites and satellites already in operation, capable of supporting Xn interface, to establish neighbor relations and to exchange configuration data with each other. Automating Xn connectivity coordination between satellite on-board gNBs may significantly reduce operator efforts each time new satellites are launched.

[0095] (2) In case of LEO where a number of satellites sequentially follow the same trajectory, there may need to establish Xn connection beyond a single hop without direct ISL connectivity (i.e., beyond directly ISL-connected neighbors). A satellite in the middle may need to perform XnAP routing and relaying, which may not always be feasible depending on processing loads.

[0096] (3) Xn connectivity between satellite on-board gNBs may not be handled similarly to legacy Xn connectivity between earth-fixed gNBs (in terrestrial network or between NTN gNBs on the ground for transparent payloads). Xn connection traversing through space may introduce more challenges, such as frequent changes in connectivity based on planned trajectories, or prone to potential outages over ISL. The relevant timers in XnAP may need to be adjusted or adapted differently. Or, if a satellite loses ISL connection with its neighbor, it may impact other nearby satellite on-board gNBs that have established Xn connections with that lost neighbour through this satellite, and may need to be timely notified.

[0097] (4) Beam direction and motion of the beam's foot print on Earth of a satellite on-board gNB may change over time, which may lead to changes of coverage and reference location of cells, and potentially affect the mobility decisions of Xn-connected neighbours.

[0098] (5) It is also expected that not all XnAP functions will be supported for satellite on-board gNBs due to their power / processing constraints and limited ISL transport capability (compared to the on-the-ground transport network's capability).

[0099] Based on the observations mentioned above, some mechanisms are proposed for Xn connection management between satellite on-board gNBs according to implementations of the present disclosure.

[0100] More specifically, the adaptation of existing terrestrial Xn interface connection management to support the dynamic and efficient management of Xn interface connections between satellite on-board gNBs over rapidly and constantly changing ISL connection is proposed according to implementations of the present disclosure.

[0101] In addition, routing and relaying mechanisms that enable Xn interface connection beyond direct ISL links, which is critical for LEO satellites, are also proposed according to implementations of the present disclosure.

[0102] In other words, the proposed method according to implementations of the present disclosure provides mechanisms for interface connection management between satellite base stations, including interface management information (e.g., multi-hop connection capability, interface stability duration, etc.), based on which the first satellite base station can establish multi-hop interface connections with other satellite base stations. The proposed method according to implementations of the present disclosure also describes exchange of other information (e.g., identification for satellite base station, etc.) and dynamic updates between satellite base stations in response to changes in the interface management information.

[0103] The following drawings are created to explain specific embodiments of the present disclosure. The names of the specific devices or the names of the specific signals / messages / fields shown in the drawings are provided by way of example, and thus the technical features of the present disclosure are not limited to the specific names used in the following drawings.

[0104] FIG. 7 shows an example of a method to which implementations of the present disclosure are applied.

[0105] In step S700, the method comprises transmitting, by a first satellite base station, an interface setup request message to a second satellite base station. The interface setup request message includes information related to the first satellite base station.

[0106] In step S710, the method comprises receiving, by the first satellite base station, a response message from the second satellite base station in response to the interface setup request message.

[0107] In some implementations, the response message may include interface management information associated with the second satellite base station and other satellite base stations having an interface connection with the second satellite base station.

[0108] For example, the interface management information may include at least one of i) information related to whether a multi-hop interface connection can be enabled for each of the other satellite base stations, or ii) information related to a duration for which an interface is expected to remain stable with the first satellite base station and / or the other satellite base stations.

[0109] For example, the interface management information　may include at least one of i) identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, or ii) transport protocol layer information and / or routing information required for establishing a multi-hop interface connection with the other satellite base stations. The identification information of the second satellite base station and / or the other satellite base stations may be based on pre-configured transport layer protocol-related information before deployment of satellite base stations.

[0110] In some implementations, the method may further comprise, determining, by the first satellite base station, to establish an interface connection with a third satellite base station based on the received interface management information, transmitting, by the first satellite base station, a second interface setup request message to the third satellite base station via the second satellite base station, and receiving, by the first satellite base station, a second response message from the third satellite base station via the second satellite base station in response to the second interface setup request message. The second interface setup request message includes information related to the first satellite base station

[0111] In some implementations, the second interface setup request message may include information informing the second satellite base station of the third satellite base station with which an interface connection is to be established.

[0112] In some implementations, the information related to the first satellite base station to be included in the interface setup request message or the second interface setup request message may include at least one of a specific gNB ID reserved for satellite base stations, or NTN specific cell configuration information. The NTN specific cell configuration information may include at least one of ephemeris information, supported Tracking Area Identities (TAI), or supported functions.

[0113] In some implementations, the method may further comprise, receiving, by the first satellite base station, an interface update message　from the second satellite base station based on change of the interface management information.

[0114] For example, the change of the interface management information may include at least one of change of identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, change of availability of multi-hop interface connection, change of transport protocol layer information and / or routing information, or change of expected duration of interface connection stability.

[0115] In some implementations, the method may further comprise establishing, by the first satellite base station, a transport layer protocol connection with the second satellite base station over ISL based on transport layer protocol information. The transport layer protocol information may be configured from a core network after a connection with the core network becomes operational after the first base satellite bae station is deployed.

[0116] In some implementations, the response message may include a reason for rejection based on the second satellite base station rejecting a request of the first satellite base station by the interface setup request message.

[0117] Furthermore, the method described above in FIG. 7 may be performed by a base station. The base station may be implemented by the second wireless device 200 shown in FIG. 2.

[0118] The base station comprises at least one transceiver, at least one processor, and at least one memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform the method described in FIG. 7.

[0119] More specifically, the first satellite base station transmits, via the at least one transceiver, an interface setup request message to a second satellite base station. The interface setup request message includes information related to the first satellite base station.

[0120] The first satellite base station receives, via the at least one transceiver, a response message from the second satellite base station in response to the interface setup request message.

[0121] In some implementations, the response message may include interface management information associated with the second satellite base station and other satellite base stations having an interface connection with the second satellite base station.

[0122] For example, the interface management information may include at least one of i) information related to whether a multi-hop interface connection can be enabled for each of the other satellite base stations, or ii) information related to a duration for which an interface is expected to remain stable with the first satellite base station and / or the other satellite base stations.

[0123] For example, the interface management information　may include at least one of i) identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, or ii) transport protocol layer information and / or routing information required for establishing a multi-hop interface connection with the other satellite base stations. The identification information of the second satellite base station and / or the other satellite base stations may be based on pre-configured transport layer protocol-related information before deployment of satellite base stations.

[0124] In some implementations, the first satellite base station may further determine to establish an interface connection with a third satellite base station based on the received interface management information, transmit, via the at least one transceiver, a second interface setup request message to the third satellite base station via the second satellite base station, and receive, via the at least one transceiver, a second response message from the third satellite base station via the second satellite base station in response to the second interface setup request message. The second interface setup request message includes information related to the first satellite base station

[0125] In some implementations, the second interface setup request message may include information informing the second satellite base station of the third satellite base station with which an interface connection is to be established.

[0126] In some implementations, the information related to the first satellite base station to be included in the interface setup request message or the second interface setup request message may include at least one of a specific gNB ID reserved for satellite base stations, or NTN specific cell configuration information. The NTN specific cell configuration information may include at least one of ephemeris information, supported Tracking Area Identities (TAI), or supported functions.

[0127] In some implementations, the first satellite base station may further receive, via the at least one transceiver, an interface update message　from the second satellite base station based on change of the interface management information.

[0128] For example, the change of the interface management information may include at least one of change of identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, change of availability of multi-hop interface connection, change of transport protocol layer information and / or routing information, or change of expected duration of interface connection stability.

[0129] In some implementations, the first satellite base station may further establish a transport layer protocol connection with the second satellite base station over ISL based on transport layer protocol information. The transport layer protocol information may be configured from a core network after a connection with the core network becomes operational after the first base satellite bae station is deployed.

[0130] In some implementations, the response message may include a reason for rejection based on the second satellite base station rejecting a request of the first satellite base station by the interface setup request message.

[0131] FIGS. 8 to 11 show an example of a procedure for Xn connection management between satellite on-board gNBs to which implementations of the present disclosure are applied.

[0132] The implementation of the present disclosure described in FIG. 7 above may be applied to the implementation of the present disclosure to be described in FIGS. 8 to 11, and vice versa.

[0133] The procedures to be described in FIGS. 8 to 11 may occur at specific instances (or event-based) and / or be executed in a coordinated or unordered manner throughout the overall process to support Xn connection management between satellite on-board gNBs.

[0134] Operation of FIG. 8 is described first.

[0135] In step S800, satellite on-board gNB1 / gNB2 / gNB3 may be pre-configured by Operation Administration Maintenance (OAM). The pre-configuration by the OAM may include a specific gNB ID reserved for satellite on-board gNBs.

[0136] In step S802, the satellite on-board gNB1 may be newly launched. Additionally and / or alternatively, ISL connection may be planned with a new neighbor satellite on-board gNB.

[0137] In step S804, after the NG connection between the first satellite on-board gNB1 and the 5GC is established, the 5GC may perform configuration update towards the satellite on-board gNB1 via the NG connection.

[0138] In step S806, the satellite on-board gNB1 may establish ISL with a neighbor satellite on-board gNB (e.g., satellite on-board gNB2).

[0139] Additionally and / or alternatively, in step S808, the satellite on-board gNB1 may establish transport layer protocol connection with a neighbor satellite on-board gNB (e.g., satellite on-board gNB2) over ISL. The satellite on-board gNBs may be configured with transport layer protocol related information for their XnAP signaling to be used when establishing transport layer protocol connection over ISL.

[0140] The transport layer protocol related information may be used by a nearby satellite on-board gNB to identify that the Xn connection setup request is from the satellite on-board gNB. The transport layer protocol related information may include, e.g., local IP address, a port number, or a Payload Protocol Identifier (PPID) number if Stream Control Transmission Protocol (SCTP) is used, etc. transport layer protocol related information may be standardized for the exclusive use by any satellite on-board gNB, or pre-configured by OAM before deployed (e.g., by step S800 above), or configured from 5GC after NGAP becomes operational after deployed (e.g., by step S804 above).

[0141] In step S810, after ISL physical layer and / or transport layer protocol connection is successfully established with a nearby satellite on-board gNB (e.g., satellite on-board gNB2), the satellite on-board gNB1 may initiate a connection setup by transmitting an interface setup request message to the satellite on-board gNB2. For example, the satellite on-board gNB1 may initiate a Xn connection setup by transmitting an Xn Setup Request message to the satellite on-board gNB2.

[0142] The interface setup request message may include information informing the satellite on-board gNB. For example, the interface setup request message may include information related to the satellite on-board gNB1. The information informing the satellite on-board gNB may be an explicit indicator, or a specific gNB ID pre-configured by OAM before deployed (e.g., by step S800 above), etc.

[0143] Additionally and / or alternatively, the interface setup request message may also include configuration data of the satellite on-board gNB. The configuration data may include e.g., ephemeris information, supported TAI over time, and / or supported XnAP functions or versions.

[0144] Alternatively, other XnAP non-UE-associated signaling message may be used to carry the information informing the satellite on-board gNB after XnAP becomes operational.

[0145] Upon receiving the interface setup request from the satellite on-board gNB1, in step S812, the satellite on-board gNB2 may reply back to the satellite on-board gNB1 by transmitting a response message to the satellite on-board gNB1. For example, the satellite on-board gNB2 may transmit an Xn Setup Response message and / or Xn Setup Failure message to the satellite on-board gNB1 in response to the Xn Setup Request message.

[0146] If the satellite on-board gNB2 accepts the request of the satellite on-board gNB1, the response message may be an interface setup response message (e.g., Xn Setup Response message). In this case, the interface setup response message may include interface management information, which may include at least one of the followings.

[0147] - Information and / or configuration data of its own (e.g., satellite on-board gNB2) and Xn-connected neighboring gNB(s) (e.g., satellite on-board gNB3);

[0148] - Xn connection relaying support information, e.g., information indicative of whether multi-hop interface connection can be enabled for each satellite on-board gNBs: may be configured for each of the Xn-connected neighboring gNB(s);

[0149] - Corresponding routing information that may be used by the requesting satellite on-board gNB (e.g., satellite on-board gNB1);

[0150] - Xn connection available or remaining time with the requesting satellite on-board gNB (e.g., satellite on-board gNB1) and / or with its Xn-connected neighboring gNB(s) (e.g., satellite on-board gNB3): For example, information on the duration for which the interface connection is expected to remain stable with the satellite on-board gNB1 and other satellite on-board gNBs (e.g., satellite on-board gNB3).

[0151] Otherwise, if the satellite on-board gNB2 rejects the request of the satellite on-board gNB1, the response message may be an interface setup failure message (e.g., Xn Setup Failure message). In this case, the interface setup failure message may include the reason for rejection (e.g., overload), and / or time to wait for the next Xn connection setup request.

[0152] Upon establishing a new interface setup between the satellite on-board gNB1 and the satellite on-board gNB2, in step S820 and S822, the satellite on-board gNB2 and the satellite on-board gNB3 may perform configuration update procedure by e.g., exchanging NG-RAN Configuration Update message and NG-RAN Configuration update acknowledge message.

[0153] Operation of FIG. 9, which may follow the operation of FIG. 8, is described.

[0154] Upon receiving the interface setup response message including the interface management information from the satellite on-board gNB2, in step S900, the satellite on-board gNB1 may initiate a connection setup beyond a single hop without direct ISL connection by transmitting an interface setup request message. For example, the satellite on-board gNB1 may initiate a Xn connection setup by transmitting an Xn Setup Request message towards the satellite on-board gNB with which direct ISL connection does not exist.

[0155] The establishment of a connection setup beyond a single hop without direct ISL connection may be determined based on the received information from direct ISL-connected neighbor satellite on-board gNB (e.g., satellite on-board gNB2). For example, the establishment of a connection setup with the satellite on-board gNB3 may be determined based on the interface management information included in the interface setup response message received from the satellite on-board gNB2. For example, the establishment of a connection setup with the satellite on-board gNB3 may be determined based on at least one of e.g., the availability of Xn connection relaying support and routing information, the availability of Xn connection available or remaining time over multi-hop ISLs toward the satellite on-board gNB(s) that Xn connection setup is requested to, etc.

[0156] Upon determining to establish of a connection setup beyond a single hop without direct ISL connection, the interface setup request message may additionally include information to identify the destination satellite on-board gNB (e.g., satellite on-board gBN3) for proper routing of Xn connection setup (i.e., via the satellite on-board gNB2).

[0157] Upon receiving the interface setup request from the satellite on-board gNB1, in step S902, the satellite on-board gNB3 may reply back to the satellite on-board gNB1 by transmitting a response message to the satellite on-board gNB1. For example, the satellite on-board gNB3 may transmit an Xn Setup Response message and / or Xn Setup Failure message to the satellite on-board gNB1 in response to the Xn Setup Request message.

[0158] Operation of FIG. 10, which may follow the operation of FIG. 8 and / or FIG. 9, is described.

[0159] Upon detecting changes of the interface management information, in step S1000, the satellite on-board gNB2 may initiate an XnAP procedure toward neighboring Xn-connected satellite on-board gNB(s) to inform the interface management information change. For example, the satellite on-board gNB2 may transmit a NG-RAN Configuration Update message to the satellite on-board gNB1 and / or the satellite on-board gNB3.

[0160] The changes of the interface management information may include e.g., updates of identification or cell configuration of the satellite on-board gNB1 and / or the satellite on-board gNB3, changes in the availability of multi-hop interface connection, updates of transport layer protocol connection or routing information, or modifications to the expected duration of interface connection stability.

[0161] Upon receiving the configuration update message from the satellite on-board gNB2, in step S1002, the neighbor satellite on-board gNB(s) may transmit a configuration update acknowledge message to the satellite on-board gNB2. For example, the satellite on-board gNB1 and / or the satellite on-board gNB3 may transmit a NG-RAN Configuration Update Acknowledge message to the satellite on-board gNB2.

[0162] Operation of FIG. 11, which may follow the operation of FIG. 8 and / or FIG. 9 and / or FIG. 10, is described.

[0163] In step S1100, the existing connection between the satellite on-board gNB2 and the satellite on-board gNB3 is disconnected. For example, the existing connection between the satellite on-board gNB2 and the satellite on-board gNB3 may be disconnected due to e.g., Xn interface tore-down or ISL lost.

[0164] Upon detecting disconnection with the satellite on-board gNB3, in step S1110, the satellite on-board gNB2 may initiate an XnAP procedure toward neighboring Xn-connected satellite on-board gNB(s) to inform the disconnection. For example, the satellite on-board gNB2 may transmit a NG-RAN Configuration Update message to the satellite on-board gNB1.

[0165] Upon receiving the configuration update message from the satellite on-board gNB2, the neighbor satellite on-board gNB(s) may transmit a configuration update acknowledge message to the satellite on-board gNB2. For example, the satellite on-board gNB1 may transmit a NG-RAN Configuration Update Acknowledge message to the satellite on-board gNB2.

[0166] The present disclosure may have various advantageous effects.

[0167] For example, the dynamic and efficient management of Xn interface connections between satellite on-board gNBs over ISL can be enabled.

[0168] For example, operator efforts can be significantly reduced whenever new satellites are launched by automating Xn connectivity coordination between satellite on-board gNBs.

[0169] For example, a satellite on-board gNB in the middle can perform XnAP routing and relaying when there is need to establish Xn connection beyond a single hop without direct ISL connectivity.

[0170] Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and / or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.

[0171] Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method. Other implementations are within the scope of the following claims.

Claims

1.A method comprising:transmitting, by a first satellite base station, an interface setup request message to a second satellite base station,wherein the interface setup request message includes information related to the first satellite base station; andreceiving, by the first satellite base station, a response message from the second satellite base station in response to the interface setup request message.2.The method of claim 1, wherein the response message includes interface management information associated with the second satellite base station and other satellite base stations having an interface connection with the second satellite base station.3.The method of claim 2, wherein the interface management information　includes at least one of i) information related to whether a multi-hop interface connection can be enabled for each of the other satellite base stations, or ii) information related to a duration for which an interface is expected to remain stable with the first satellite base station and / or the other satellite base stations.4.The method of claim 2 or 3, wherein the interface management information　includes at least one of i) identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, or ii) transport protocol layer information and / or routing information required for establishing a multi-hop interface connection with the other satellite base stations.5.The method of claim 4, wherein the identification information of the second satellite base station and / or the other satellite base stations is based on pre-configured transport layer protocol-related information before deployment of satellite base stations.6.The method of any claims 2 to 5, wherein the method further comprises:determining, by the first satellite base station, to establish an interface connection with a third satellite base station based on the received interface management information;transmitting, by the first satellite base station, a second interface setup request message to the third satellite base station via the second satellite base station,wherein the second interface setup request message includes information related to the first satellite base station; andreceiving, by the first satellite base station, a second response message from the third satellite base station via the second satellite base station in response to the second interface setup request message.7.The method of claim 6, wherein the second interface setup request message includes information informing the second satellite base station of the third satellite base station with which an interface connection is to be established.8.The method of any claim 1 to 7, wherein the information related to the first satellite base station to be included in the interface setup request message or the second interface setup request message includes at least one of a specific gNB Identifier (ID) reserved for satellite base stations, or NTN specific cell configuration information.9.The method of claim 8, wherein the NTN specific cell configuration information includes at least one of ephemeris information, supported Tracking Area Identities (TAI), or supported functions.10.The method of any claims 2 to 9, wherein the method further comprises:receiving, by the first satellite base station, an interface update message　from the second satellite base station based on change of the interface management information.11.The method of claim 10, wherein the change of the interface management information includes at least one of change of identification information and / or cell configuration information of the second satellite base station and / or the other satellite base stations, change of availability of multi-hop interface connection, change of transport protocol layer information and / or routing information, or change of expected duration of interface connection stability.12.The method of any claim 1 to 11, wherein the method further comprises:establishing, by the first satellite base station, a transport layer protocol connection with the second satellite base station over inter-satellite link (ISL) based on transport layer protocol information.13.The method of claim 12, wherein the transport layer protocol information is configured from a core network after a connection with the core network becomes operational after the first base satellite bae station is deployed.14.The method of claim 1, wherein the response message includes a reason for rejection based on the second satellite base station rejecting a request of the first satellite base station by the interface setup request message.15.A base station comprising:at least one transceiver;at least one processor; andat least one memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform the method of any claims 1 to 14.

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