Device and method for providing link between satellite and satellite in non-terrestrial network

Abstract

To provide a satellite device for providing non-terrestrial network (NTN) access.SOLUTION: A device of each of satellites 801-805 includes a memory containing instructions, at least one processor, and at least one transceiver. The instructions, when executed by the processor, cause the device to receive a request message for a call connection from a terminal 811 through the transceiver, identify a destination satellite corresponding to a destination terminal 815 of the request message, determine whether a direct link to the destination satellite is possible, transmit an instruction message for a call connection with the terminal and the destination terminal to the destination satellite through the transceiver if a direct link to the destination satellite is possible, and identify a second satellite that can form a direct link with the satellite and transmit the instruction message to the second satellite through the transceiver if the direct link to the destination satellite is not possible.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] This disclosure generally relates to a non-terrestrial network (NTN) that provides wireless communication services through satellites located in Earth orbit or aerial vehicles flying at high altitudes, rather than terrestrial base stations on the ground. In particular, it focuses on providing links between satellites.

Background Art

[0002] To complement terrestrial networks that provide wireless communication systems, non-terrestrial networks (NTNs) have been introduced. Non-terrestrial networks can provide communication services even in areas where it is difficult to build terrestrial networks or in disaster situations. Also, due to the recent decrease in satellite launch costs, an efficient access network environment can be provided.

Summary of the Invention

Means for Solving the Problems

[0003] In an embodiment, a satellite device for providing NTN access is provided. The device can include a memory containing instructions, at least one processor, and at least one transceiver. When the instructions are executed by the at least one processor, the device receives a request message for a call connection from a terminal through the at least one transceiver, identifies a target satellite corresponding to the target terminal of the request message, determines whether a direct link to the target satellite is possible, and if a direct link to the target satellite is possible, transmits an instruction message for a call connection between the terminal and the target terminal to the target satellite through the at least one transceiver. If a direct link to the target satellite is not possible, it can identify a second satellite with which a direct link can be formed and cause the instruction message to be transmitted to the second satellite through the at least one transceiver.

[0004] In an embodiment, a method performed by a satellite for providing NTN access is provided. The method can include receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to the target terminal of the request message, determining whether a direct link to the target satellite is possible, if a direct link to the target satellite is possible, transmitting an instruction message for a call connection between the terminal and the target terminal to the target satellite, if a direct link to the target satellite is not possible, identifying a second satellite with which a direct link can be formed, and transmitting the instruction message to the second satellite.

[0005] In an embodiment, a non-transitory storage medium is provided. It can include a memory containing instructions. When the instructions are executed by a satellite's processor, the satellite receives a request message for a call connection from a terminal, identifies a target satellite corresponding to the target terminal of the request message, determines whether a direct link to the target satellite is possible, and if a direct link to the target satellite is possible, transmits an instruction message for a call connection between the terminal and the target terminal to the target satellite. If a direct link to the target satellite is not possible, it can identify a second satellite with which a direct link can be formed and cause the instruction message to be transmitted through the second satellite.

Brief Description of the Drawings

[0006]

Figure 1

Figures 2a - 2b

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Figure 3b

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Figure 5

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Figure 6b

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Figure 7b

Figure 8

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Mode for Carrying Out the Invention

[0007] The terms used in this disclosure are merely used to explain specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions can include plural expressions unless the context clearly indicates otherwise. The terms used herein, including technical or scientific terms, can have the same meaning as commonly understood by those of ordinary skill in the technical field described in this disclosure. Among the terms used in this disclosure, terms defined in a general dictionary can be interpreted in the same or similar meaning as the meaning in the context of the related art, and unless clearly defined in this disclosure, they are not interpreted in an ideal or overly formal meaning. In some cases, even terms defined in this disclosure cannot be interpreted so as to exclude the embodiments of this disclosure.

[0008] In various embodiments of the present disclosure described below, a hardware approach is exemplified. However, since various embodiments of the present disclosure include technologies that use both hardware and software, various embodiments of the present disclosure do not exclude software-based approaches.

[0009] Terms used to refer to signals (e.g., signal, information, message, signaling), terms used to refer to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), occasion), terms for operational states (e.g., step, operation, procedure), terms used to refer to data (e.g., packet, user stream, information, bit, symbol, codeword), terms used to refer to channels, terms used to refer to network entities, terms used to refer to components of a device, etc. are exemplified for the convenience of explanation. Therefore, the present disclosure is not limited to the terms described hereinafter, and other terms having equivalent technical meanings may be used.

[0010] In the following description, a physical channel and a signal may be used interchangeably with data or a control signal. For example, PDSCH (physical downlink shared channel) is a term that refers to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmit a physical channel" may be interpreted equivalently to the expression "transmit data or a signal through a physical channel".

[0011] Hereinafter, in the present disclosure, higher-layer signaling means a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel or from a terminal to a base station using a physical layer uplink data channel. Higher-layer signaling may be understood as RRC (radio resource control) signaling or a MAC control element (hereinafter "CE").

[0012] In addition, in the present disclosure, expressions of "exceeding" or "less than" may be used to determine whether specific conditions are satisfied or fulfilled, but this is merely a description for illustrative purposes and does not exclude descriptions of "greater than or equal to" or "less than or equal to". The condition described as "greater than or equal to" may be replaced by "exceeding", the condition described as "less than or equal to" may be replaced by "less than", and the condition described as "greater than or equal to and less than or equal to" may be replaced by "exceeding and less than". Also, hereinafter, "A" to "B" means at least one of the elements from A (including A) to B (including B). Hereinafter, "C" and / or "D" means at least one of "C" or "D", that is, it includes {"C", "D", "C and D"}.

[0013] In the present disclosure, the quality of a signal can be, for example, at least one of 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), BLER (block error rate). Needless to say, in addition to the above-described examples, other terms having an equivalent technical meaning or other metrics indicating the quality of a channel may be used. Hereinafter, when the quality of a signal is high in the present disclosure, it means that the signal quality value related to the magnitude of the signal is large or the signal quality value related to the error rate is small. The higher the signal quality, the smoother the wireless communication environment can be guaranteed. Also, the optimal beam may mean the beam with the highest signal quality among the beams.

[0014] This disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), ETSI (European Telecommunications Standards Institute)), which are merely illustrative for the purpose of explanation. The various embodiments of this disclosure can be easily modified and applied in other communication systems as well.

[0015] FIG. 1 illustrates a wireless communication system.

[0016] Referring to FIG. 1, FIG. 1 is a radio interface of a radio access technology (RAT), and illustrates a terminal 110 and a base station 120 as part of a node that utilizes a radio channel in a wireless communication system using New Radio (NR). Although FIG. 1 illustrates only one base station, the wireless communication system can further include other base stations that are the same as or similar to the base station (e.g., NR gNB) 120.

[0017] The terminal 110 is a device used by a user and communicates with the base station 120 through a radio channel. The link from the base station 120 to the terminal 110 is referred to as the downlink (DL), and the link from the terminal 110 to the base station 120 is referred to as the uplink (UL). Also, although not illustrated in FIG. 1, the terminal 110 and other terminals can communicate with each other through a mutual radio channel. At this time, the link between the terminal 110 and other terminals (device-to-device link, D2D) is referred to as a sidelink, and the sidelink can be used interchangeably with the PC5 interface. In some other embodiments, the terminal 110 can be operated without the involvement of the user. According to one embodiment, the terminal 110 is a device that performs machine type communication (MTC) and does not have to be carried by the user. Also, according to one embodiment, the terminal 110 can be a NB (narrowband)-IoT (internet of things) device.

[0018] In describing the system and method in this specification, the terminal 110 can be an electronic device used to communicate voice and / or data to the base station 120, and the base station 120 can in turn communicate with a network of devices (e.g., a public switched telephone network (PSTN), the Internet, etc.).

[0019] Also, the terminal 110 can be referred to by other terms having the same technical meaning as "user equipment (UE)" outside the terminal, "vehicle", "customer premises equipment (CPE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "electronic device", or "user device", "access terminal", "mobile terminal", "remote station", "user terminal", "subscriber unit", "mobile device", or the like.

[0020] Examples of the terminal 110 include cellular phones, smartphones, personal digital assistants (PDAs), laptop computers, netbooks, e-readers, wireless modems, etc. In 3GPP specifications, the terminal 110 is typically referred to as a UE. However, since the scope disclosed in this specification should not be limited to the 3GPP standard, the terms "UE" and "terminal" can be used interchangeably in this specification to mean the more general term "wireless communication device". The UE can also be more generally referred to as a terminal device.

[0021] Base station 120 is a network infrastructure that provides a wireless connection to terminal 110. Terminal 110 has a coverage defined based on the distance over which it can transmit signals. In 3GPP standards, base station 120 is generally referred to as "Node B", "evolved Node B (eNodeB)", "5G node", "gNodeB (next generation NodeB)", "Home Enhanced or evolved Node B (HeNB)", in addition to "access point (AP)", "wireless point", "transmission / reception point (TRP)", or other terms having an equivalent technical meaning.

[0022] Since the scope of the content disclosed in this specification should not be limited to 3GPP standards, the terms "base station", "Node B", "eNodeB", and "HeNB" can be used interchangeably in this specification to mean the more general term "base station". Also, the term "base station" can be used to denote an access point. An access point can be an electronic device that provides access to a network (e.g., a short-range network (LAN), the Internet, etc.) for wireless communication devices. The term "communication device" can be used to denote all wireless communication devices and / or base stations. eNodeB or gNodeB can also be more generally referred to as a base station device.

[0023] The base station 120 can communicate with an NR Core Network (NR CN) entity 130. For example, the core network entity 130 can include an AMF (Access and Mobility Management Function) responsible for the control plane such as terminal 110 connection and mobility control functions, and a UPF (User Plane Function) responsible for control functions for user data.

[0024] The terminal 110 can perform beamforming with the base station 120. The terminal 110 and the base station 120 can transmit and receive radio signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). Also, the terminal 110 and the base station 120 can transmit and receive radio signals in a relatively high frequency band (e.g., FR 2 (or FR 2-1, FR 2-2, FR 2-3), FR 3 of NR), millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz). For improving channel gain, the terminal 110 and the base station 120 can perform beamforming. Here, beamforming can include transmit beamforming and receive beamforming. The terminal 110 and the base station 120 can impart directivity to the transmitted or received signal. For this purpose, the terminal 110 and the base station 120 can select a serving beam through a beamsearch or beam management procedure. After the serving beam is selected, subsequent communication can be performed through the resource that transmitted the serving beam and the resource in a Quasi Co-Location (QCL) relationship.

[0025] If the large-scale characteristics of the channel that transmitted the symbols on the first antenna port can be inferred from the channel that transmitted the symbols on the second antenna port, then the first antenna port and the second antenna port can be evaluated as being in a QCL relationship. For example, the large-scale characteristics can include at least one of delay spread, doppler spread, doppler shift, average gain, average delay, and spatial receiver parameter.

[0026] Both the terminal 110 and the base station 120 can perform beamforming, but the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal 110 may or may not perform beamforming. Also, the base station 120 may or may not perform beamforming. That is, only one of the terminal 110 and the base station 120 may perform beamforming, or neither the terminal 110 nor the base station 120 may perform beamforming.

[0027] As used in this disclosure, a "beam" refers to the spatial flow of a signal over a wireless channel, which is formed by one or more antennas (or antenna elements), and such a formation process may be referred to as beamforming. Beamforming can include at least one of analog beamforming or digital beamforming (e.g., Precoding). The reference signals transmitted based on beamforming can include, for example, DM-RS (demodulation-reference signal), CSI-RS (channel state information-reference signal), SS / PBCH (synchronization signal / physical broadcast channel), and SRS (sounding reference signal). Also, as a configuration for each reference signal, an IE (information element) such as a CSI-RS resource or an SRS-resource may be used, and such a configuration can include information associated with the beam. Information associated with the beam can mean whether the corresponding configuration (e.g., CSI-RS resource) uses the same spatial domain filter as another configuration (e.g., another CSI-RS resource within the same CSI-RS resource set) or a different spatial domain filter, or which reference signal is quasi-co-located (QCL) with it, and if it is QCL, what type (e.g., QCL type A, B, C, D) it is.

[0028] Hereinafter, for the purpose of describing embodiments, the terminal may be referred to as UE110, and the base station may be referred to as gNB120.

[0029] Figures 2a and 2b illustrate examples of non-terrestrial networks (NTNs). In Figure 2a, an example of an NTN that uses a transparent satellite is illustrated. In Figure 2b, an example of an NTN that uses a regenerative satellite is illustrated. NTN means an NG-RAN that provides non-terrestrial NR access to a UE (e.g., UE110) through an NTN payload mounted on an airborne or space-borne NTN vehicle and an NTN gateway. The NG-RAN can include one or more gNBs (e.g., gNB120).

[0030] Referring to Figure 2a, NTN 200 shows the network environment by the transparent satellite. NTN 200 can be a gNB 120 and can include an NTN payload 221 and an NTN gateway 223. The NTN payload 221 is a network node mounted on a satellite or a high altitude platform station (HAPS) that provides a connection function between a service link (described later) and a feeder link (described later). The NTN gateway 223 is an earth station located on the earth's surface that provides a connection to the NTN payload 221 using the feeder link. The NTN gateway 223 is a transport network layer (TNL) node. NTN 200 can provide non-terrestrial NR access to UE 110. NTN 200 can provide non-terrestrial NR access to UE 110 through the NTN payload 221 and the NTN gateway 223. The link between the NTN payload 221 and UE 110 can be referred to as a service link. The link between the NTN gateway 223 and the NTN payload 221 can be referred to as a feeder link. The feeder link can correspond to a wireless link.

[0031] The NTN payload 221 can receive radio protocol data from the UE 110 through the service link. The NTN payload 221 can transparently transmit the radio protocol data to the NTN gateway 223 through the feeder link. Therefore, the NTN payload 221 and the NTN gateway 223 may appear as one gNB 120 from the perspective of the UE 110. The NTN payload 221 and the NTN gateway 223 can communicate with the UE 110 through the Uu interface, which is a common radio protocol. That is, the NTN payload 221 and the NTN gateway 223 can perform radio protocol communication with the UE 110 as if they were one gNB 120. The NTN gateway 223 can communicate with the core network entity 235 (AMF or UPF) through the NG interface.

[0032] According to one embodiment, the NTN payload 221 and the NTN gateway 223 can utilize the radio protocol stack in the control plane of FIG. 3a, which will be described later. Also, according to one embodiment, the NTN payload 221 and the NTN gateway 223 can utilize the radio protocol stack in the user plane of FIG. 3b.

[0033] In FIG. 2a, one NTN payload 221 and one NTN gateway 223 included in the gNB 120 are described, but the embodiments of the present disclosure are not limited thereto. For example, the gNB can include multiple NTN payloads. Also, for example, the NTN payload can be provided by multiple gNBs. That is, the implementation scenario illustrated in FIG. 2a is an example and does not limit the embodiments of the present disclosure.

[0034] Referring to FIG. 2b, NTN250 shows the network environment by the reproducing satellite. NTN250 can include a satellite 260 operating as a gNB120. The satellite 260 represents a space-borne vehicle equipped with a regenerative payload communication transmitter placed in a low-earth orbit (LEO), a medium-earth orbit (MEO), or a geostationary earth orbit (GEO). The satellite 260 can be referred to as a regenerative payload or a reproducing satellite. The satellite 260 represents a vehicle configured to convert and amplify an uplink RF signal before transmitting it to the downlink, and the conversion of the signal can mean digital processing that can include demodulation, decoding, re-encoding, remodulation, and / or filtering. NTN250 can include an NTN gateway 265, which is an entity placed on the ground and connected to the satellite 260. The NTN gateway 265 is an earth station placed on the earth's surface that provides a connection to the satellite 260 using the feeder link. NTN250 can provide non-terrestrial NR access to the UE110. NTN250 can provide non-terrestrial NR access to the UE110 through the satellite 260 and the NTN gateway 265.

[0035] The satellite 260 may be configured to reproduce signals received from the Earth. A Uu interface may be defined between the satellite 260 and the terminal 110. An SRI (satellite radio interface) on the feeder link may be defined between the satellite 260 and the NTN gateway 265. Although not shown in FIG. 2b, the satellite 260 may provide inter-satellite ISLs (inter-satellite links). The ISL may be a transmission link between satellites, and the ISL may be a radio interface defined by 3GPP (e.g., XN interface) or an optical interface not defined by 3GPP. The satellite 260 can communicate with the core network entity 235 (AMF or UPF) through the NG interface based on the NTN gateway 265. According to one embodiment, the satellite 260 can utilize the radio protocol stack in the control plane of FIG. 3a described later. Also, according to one embodiment, the satellite 260 can utilize the radio protocol stack in the user plane of FIG. 3b.

[0036] Although the satellite 260 operating as the gNB 120 was described in FIG. 2B, embodiments of the present disclosure are not limited thereto. The gNB 120 according to the embodiment may be implemented in a distributed deployment using a centralized unit (CU) configured to perform functions of upper layers (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) of the access network and a distributed unit (DU) configured to perform functions of lower layers. The interface between the CU and the DU (distributed unit) may be referred to as the F1 interface. The CU (centralized unit) is connected to one or more DUs and can be responsible for functions of layers higher than the DU. For example, the CU can be responsible for functions of the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, and the DU and the radio unit (RU) can be responsible for functions of lower layers. The DU can be responsible for functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. In such a distributed deployment, the satellite 260 can be used as the CU or DU constituting the gNB 120.

[0037] FIG. 3A illustrates an example of a control plane (C-plane). Hereinafter, at least a part of the description of the gNB 120 can be understood as being for the satellite 260.

[0038] Referring to FIG. 3A, in the C-plane, the UE 110 and the AMF 235 can perform non-access stratum (NAS) signaling. In the C-plane, the UE 110 and the gNB 120 can perform communication according to protocols specified in the RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer, respectively.

[0039] With NTN access, the main functions of the RRC layer can include at least some of the following functions.

[0040] - Broadcast of AS (Access Stratum) and NAS-related system information - Paging initiated by 5GC (5G Core) or NG-RAN (Next Generation-Radio Access network) - Establishment, maintenance, and release of the RRC connection between the UE and the NG-RAN, more specifically, including control of RLC, MAC, and PHY: - Addition, modification, and release of Carrier Aggregation - Addition, modification, and release of dual connectivity between NR or E-UTRA and NR.

[0041] - Security functions including Key Management; - Establishment, configuration, maintenance, and release of SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer) - Mobility functions including: - Handover and context transfer; - UE cell selection and reselection and cell selection and reselection control; - Inter-RAT mobility.

[0042] - QoS (quality of service) management functions; - UE measurement reporting and reporting control; - Detection and recovery of radio link failure - Message transmission from / to the UE to / from the NAS.

[0043] With NTN access, the main functions of the PDCP layer can include at least some of the following functions.

[0044] - Header compression and decompression: ROHC only - Transfer of user data - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - PDCP PDU reordering for reception - Duplicate detection of lower layer SDUs - Retransmission of PDCP SDUs - Ciphering and deciphering - Timer-based SDU discard in uplink In NTN access, the main functions of the RLC layer can include at least some of the following functions

[0045] - Transfer of upper layer PDUs - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - Error Correction through ARQ - Concatenation, segmentation and reassembly of RLC SDUs - Re-segmentation of RLC data PDUs - Reordering of RLC data PDUs - Duplicate detection - Protocol error detection - RLC SDU discard - RLC re - establishment In NTN access, the MAC layer can be connected to multiple RLC layer devices configured in one terminal, and the main functions of MAC can include at least some of the following functions.

[0046] - Mapping between logical channels and transport channels - Multiplexing / demultiplexing of MAC SDUs - Scheduling information reporting - Error correction through HARQ - Priority handling between logical channels of one UE - Priority handling between UEs by means of dynamic scheduling - MBMS service identification - Transport format selection - Padding In NTN access, the physical layer can perform operations of channel coding and modulating the upper layer data, creating it into OFDM symbols for transmission over the radio channel, or demodulating the OFDM symbols received through the radio channel and performing channel decoding to transmit to the upper layer.

[0047] Figure 3b illustrates an example of the user plane (U-plane). Hereinafter, at least a part of the description of gNB 120 can be understood to apply to satellite 260.

[0048] Referring to Figure 3b, in the U-plane, UE 110 and gNB 120 can perform communication according to the protocols specified in the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer respectively. For the PDCP layer, RLC layer, MAC layer, and PHY layer excluding the SDAP layer, the description of Figure 3a can be referred to.

[0049] In NTN access, the SDAP layer can provide the QoS flow of 5GC. A single protocol entity of SDAP can be configured for each individual PDU session, and the functions of the SDAP layer can include at least some of the following functions.

[0050] - Mapping between QoS flow and data radio bearer; - QoS flow ID (QFI) indication for both DL and UL packets. Figure 4 illustrates an example of the resource structure in the time-frequency domain supported by a wireless communication system to which the embodiments proposed in this specification can be applied. Figure 4 exemplifies the basic structure of the time-frequency domain, which is a wireless resource area where data or control channels are transmitted in the downlink or uplink in a 5G NR system to which this embodiment can be applied.

[0051] Referring to Figure 4, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is the OFDM symbol, N symbA number of OFDM symbols 402 gather to form one slot 406. Referring to FIG. 4, in a wireless communication system to which the present invention is applied, one radio frame 414 can be defined as having a length of 10 ms and being composed of 10 subframes having the same length of 1 ms. And one radio frame 414 can be divided into two half-frames of 5 ms, and each half-frame includes 5 subframes. In FIG. 4, although slot 406 is composed of 14 OFDM symbols, the length of the slot can vary depending on the subcarrier spacing. For example, in the case of numerologies having a 15 kHz subcarrier spacing, the slot has a length of 1 ms and is configured to have the same length as the subframe. In contrast, in the case of numerologies having a 30 kHz subcarrier spacing, the slot is composed of 14 OFDM symbols, but has a length of 0.5 ms and two slots can be included in one subframe.

[0052] That is, the subframe and the frame are defined with fixed time lengths, and the slot is defined by the number of symbols and the time length can vary depending on the subcarrier spacing. Referring to FIG. 4 again, in a wireless communication system to which the invention proposed in this specification can be applied, the radio resources supported are composed of symbols of a plurality of time resources and sub-carriers of a plurality of frequency resources, and each time resource and frequency resource can be represented by a two-dimensional resource grid. In FIG. 4, one of the smallest physical resources composed of one subcarrier and one symbol in the resource grid is called a resource element (RE) 412.

[0053] In the wireless communication system to which the invention proposed in this specification can be applied, the minimum transmission unit in the frequency domain is a subcarrier, and the carrier bandwidth that constitutes the resource grid is composed of NBW subcarriers 404.

[0054] In the time - frequency domain, the basic unit of resources is a resource element (hereinafter referred to as "RE") 412, which can be indicated by the OFDM symbol index and the subcarrier index. A resource block 408 can include a plurality of resource elements 412. In the wireless communication system to which the invention proposed in this specification can be applied, a resource block 408 (or a physical resource block (hereinafter referred to as "PRB")) is N symb consecutive OFDM symbols in the time domain and N SC RB consecutive subcarriers in the frequency domain and can be defined. In the NR system, a resource block (RB) 408 can be defined by N SC RB consecutive subcarriers 410 in the frequency domain. One RB408 includes N SC RB resource elements 412 in the frequency axis.

[0055] Generally, the minimum transmission unit of data is an RB, and the number N SC RB of subcarriers = 12. The frequency domain can include a common resource block (CRB). A physical resource block (PRB) can be defined in a bandwidth part (BWP) on the frequency domain. The CRB and PRB numbers can be determined by the subcarrier spacing. The data rate can increase in proportion to the number of RBs scheduled for the terminal.

[0056] In the NR system, in the case of an FDD (frequency division duplex) system that operates by separating the downlink and uplink by frequency, the downlink transmission bandwidth and the uplink transmission bandwidth can be different from each other. The channel bandwidth indicates the RF (radio frequency) bandwidth corresponding to the system transmission bandwidth. [Table 1] shows a part of the correspondence between the system transmission bandwidth, subcarrier spacing (SCS), and channel bandwidth defined in the NR system in a frequency band lower than the upper limit (e.g., 7.125) GHz defined in the standard (e.g., FR (frequency range) 1 (410 MHz to 7125 MHz)). And [Table 2] shows a part of the correspondence between the transmission bandwidth, subcarrier spacing, and channel bandwidth defined in the NR system in a frequency band higher than the lower limit (e.g., 24.25 GHz) defined in the standard (e.g., FR2 (24250 MHz - 52600 MHz) or FR2-2 (52600 MHz to 71000 MHz)). For example, an NR system with a 100 MHz channel bandwidth and a 30 kHz subcarrier spacing has a transmission bandwidth composed of 273 RBs. In [Table 1] and [Table 2], N / A can be a bandwidth-subcarrier combination not supported in the NR system.

[0057]

Table 1

[0058]

Table 2

[0059] Figure 5 illustrates an example of a network structure for NTN. Satellite 260 can be mounted on a space vehicle or aerial vehicle to provide structure, power, command, telemetry, attitude control for the satellite (corresponding to HAPS), and an appropriate thermal environment and radiation shielding. In Figure 5, an example is described where satellite 260 is a reproduction carrier and operates as a complete base station (e.g., gNB120).

[0060] Referring to FIG. 5, satellite 260 can operate as gNB120. gNB120 can communicate with terminal 110 or communicate with core network entity 130. In FIG. 5, UPF550 is illustrated as core network entity 130. NR Uu interface 502 can be utilized between satellite 260 and terminal 110. According to one embodiment, at least one radio bearer 520 can be generated between satellite 260 and terminal 110. For example, radio bearer 520 can include a data radio bearer (DRB). For example, radio bearer 520 can include a signaling radio bearer (SRB). NG interface 504 can be utilized between satellite 260 and a core network entity (e.g., AMF, UPF). For example, an N3 interface can be utilized between satellite 260 and UPF. For example, an N2 interface can be utilized between satellite 260 and AMF. According to one embodiment, a traffic tunnel can be generated between satellite 260 and core network entity 130. For example, an NG-U tunnel 530 can be generated between satellite 260 and UPF550.

[0061] A PDU (packet data unit) session 540 can be generated between UE110 and a core network entity 130 (e.g., UPF550). The PDU session 540 can be utilized to provide an end-to-end user plane connection between the terminal 110 and the data network through UPF550. The PDU session 540 can support one or more QoS (quality of service) flows. For example, the PDU session 540 can support a first QoS flow 511 and a second QoS flow 512. In the user plane, the radio bearer 520 can be mapped to a QoS flow (e.g., the first QoS flow 511, the second QoS flow 512). According to one embodiment, the satellite 260 can perform the mapping between the DRB and the QoS flow as the gNB120.

[0062] Although not shown in FIG. 5, O&M (operation and maintenance) can be utilized to provide a radio access network through the satellite 260. O&M can provide one or more parameters related to the NTN500 to the gNB120 (e.g., the satellite 260). For example, O&M (operation and maintenance) 510 can provide at least the following NTN-related parameters to the gNB120 for operation.

[0063] a) Earth fixed beams: For each beam provided by a given NTN payload: - Cell identifiers (NG and Uu) mapped to the beam - Reference location of the cell (e.g., the center and the range of the cell).

[0064] b) Quasi earth fixed beams: For each beam provided by a given NTN payload: - Cell identifiers (NG and Uu) and time window mapped to the beam; - Reference position of cell / beam (e.g., center and range of cell) - Time window for continuous switch-over (feeder link, service link) - Identifiers and time windows of all satellites and NTN gateways providing services. c) Earth moving beams: For each beam provided by a given NTN payload: - Uu cell identifier mapped to the beam and mapping information to the fixed geographical area reported to the NG, information on the movement of the beam's footprint on the Earth; - Elevation for the NTN payload; - Continuous service schedule for the NTN-gateway / gNB; - Switch-over schedule (feeder link, service link).

[0065] Figure 6a illustrates an example of the control plane of a regenerative satellite (e.g., satellite 260).

[0066] Referring to Figure 6a, UE610 can support the protocols of the PHY layer, MAC layer, RLC layer, PDCP layer, and RRC layer. Satellite 620 is a gNB and can support the protocols of the PHY layer, MAC layer, RLC layer, PDCP layer, and RRC layer. For satellite 620, the description of satellite 260 can be referred to. The description of the protocols for each layer can refer to the description in Figure 3a. The interface between UE610 and satellite 620 can be the Uu interface.

[0067] Satellite 620 is a gNB on board or a part of the gNB that can perform the NG-RAN protocol function. Satellite 620 can communicate (e.g., IP communication) with the ground-based NTN gateway 630 through the SRI. Satellite 620 can be connected to the 5GC through the NTN gateway 630. As network entities for the 5GC, AMF 640 (e.g., AMF 235) and SMF 650 are exemplified. Satellite 620 can support the protocols of the NG-AP layer, SCTP (stream control transmission protocol) layer, and IP layer for communication with the 5GC. The NG-AP layer can be utilized over SCTP between the AMF 640, which is a 5GC entity, and Satellite 620 through the NTN gateway. The NAS signaling between the UE 610 and the AMF 640 can be performed through Satellite 620 and the NTN gateway 630. The NAS signaling can include the NAS-MM (mobility management) interface for the AMF 640. The NAS signaling can include the NAS-SM relay and / or NAS-SM (session management) for the SMF 650. The NAS signaling can be transmitted through the NTN gateway 630 between the AMF 640, which is a 5GC entity, and Satellite 620 through the protocol of the NG-AP layer.

[0068] In FIG. 6a, an example where the satellite operates as a complete gNB is described, but the embodiments of the present disclosure are not limited thereto. As a non-limiting example, the satellite can operate as a gNB-DU by function separation. Accordingly, the satellite may be configured to support the protocols of the RLC layer, MAC layer, and PHY layer.

[0069] FIG. 6b illustrates an example of the user plane of the regenerative satellite (e.g., Satellite 260).

[0070] Referring to FIG. 6b, UE 610 can support the protocols of the PHY layer, MAC layer, RLC layer, PDCP layer, and SDAP layer. Satellite 620 is a gNB and can support the protocols of the PHY layer, MAC layer, RLC layer, PDCP layer, and SDAP layer. The description of the protocols for each layer can refer to the description in FIG. 3b. The interface between UE 610 and satellite 620 can be the Uu interface.

[0071] Satellite 620 is a gNB mounted on a board and can perform the NG-RAN protocol function. Satellite 620 can communicate (e.g., IP communication) with the ground-based NTN gateway 630 through SRI. Satellite 620 can connect to the 5GC through NTN gateway 630. As a network entity for the 5GC, UPF 680 is exemplified. Satellite 620 can support the protocols of the GTP-U (GPRS (General Packet Radio Service) tunneling protocol-user plane) layer, UDP (user datagram protocol) layer, and IP layer for communication with the 5GC. A PDU session (e.g., PDU session 540 in FIG. 5) can be generated between UE 610 and UPF 680. The protocol stack of SRI can be used to transmit the UE user plane between the satellite and the NTN-gateway. Signals on the PDU session can be transmitted through the GTP-U tunnel between UPF 680, which is the 5GC, and satellite 620 through NTN gateway 630.

[0072] Although an example where the satellite operates as a complete gNB is described in FIG. 6b, the embodiments of the present disclosure are not limited thereto. As a non-limiting example, the satellite can operate as a gNB-DU by functional separation. Accordingly, the satellite may be configured to support the protocols of the RLC layer, MAC layer, and PHY layer.

[0073] Figure 7a shows a first example of the NTN scenario. In Figure 7a, a typical NTN scenario based on a transparent payload is illustrated.

[0074] Referring to Figure 7a, a satellite (or UAS platform) can generate a service link with a UE. The satellite (or UAS platform) can be connected to a gateway through a feeder link. The satellite can be connected to a data network through the gateway. A beam footprint can mean the area where a signal transmitted by the satellite can be received.

[0075] The following drawings are created to illustrate a specific example of this specification. Since the names of specific devices and the names of specific signals / messages / fields described in the drawings are presented exemplarily, the technical features of this specification are not limited to the specific names used in the following drawings.

[0076] Figure 7b illustrates an example of handover of a satellite (satellite as a non-terrestrial base station). In Figure 7b, a typical NTN scenario based on a regenerative payload is illustrated.

[0077] Referring to Figure 7b, a satellite (or UAS platform) can generate a service link with a UE. The satellite (or UAS platform) connected to the UE can be connected to other satellites (or UAS platforms) through Inter-satellite links (ISL). The other satellites (or UAS platforms) can be connected to a gateway through a feeder link. Based on the regenerative payload, the satellite can be connected to a data network through other satellites and the gateway. If there is no ISL between the satellite and other satellites, a feeder link between the satellite and the gateway is required.

[0078] Incidentally, the scenarios of FIGS. 7a and 7b are merely examples of NTN scenarios, and NTN can be implemented based on various scenarios.

[0079] NTN can generally be characterized by the following elements: - One or more sat-gateways (satellite gateways) that connect NTN to a shared data network: i) Geostationary Earth Orbit (GEO) satellites can be fed by one or more satellite gateways deployed across a satellite coverage area (e.g., regional or even continental coverage). It can be assumed that UEs within a cell are served by only one sat-gateway.

[0080] ii) Non-GEO satellites can be continuously served by one or more satellite gateways at a time. The system can ensure service and feeder link continuity between consecutive serving satellite gateways with a sufficient time duration for mobility anchoring and handover.

[0081] - A feeder link or wireless link between the sat-gateway and the satellite (or UAS platform).

[0082] - A service link or wireless link between the UE and the satellite (or UAS platform).

[0083] - A satellite (or UAS platform) that can embody a transparent or regenerative (with on board processing) payload. The satellite (or UAS platform) can generally generate multiple beams across a service area specified by the field of view of the satellite (or UAS platform). The footprint of the beam can generally be elliptical. The field of view of the satellite (or UAS platform) can vary depending on the on-board antenna diagram and the minimum elevation angle: i) Transparent payload: It can include radio frequency filtering, frequency conversion, and amplification. Thus, the waveform signal repeated by the payload can be unchanged; ii) Regenerative payload: It can include radio frequency filtering, frequency conversion, and amplification, demodulation / decoding, switching and / or routing, coding / modulation. The regenerative payload can be substantially the same as mounting all or part of a base station function (e.g., gNB) on the satellite (or UAS platform).

[0084] - In the case of a constellation of satellites, an inter-satellite link (ISL) can be selectively included. For this, a regenerative payload may be required on the satellite. The ISL can operate in the RF frequency or optical band.

[0085] - A UE can be served by a satellite (or UAS platform) within a targeted service area Table 3 below shows a list of various types of satellites (or UAS platforms).

[0086]

Table 3

[0087] Figure 8 illustrates an example of a signal path using an inter-satellite link (ISL). Embodiments of the present disclosure propose an apparatus and method for providing a signaling connection between two terminals through a satellite. In the present disclosure, the satellite can be a regenerative satellite or a transparent satellite. Each satellite exemplifies satellite 260 or satellite 620.

[0088] Referring to Figure 8, the first UE 811 may be connected to the first satellite 801. For example, the first satellite 801 can provide a first cell. The first UE 811 may be connected on the first cell. The user of the first UE 811 may want to communicate with the user of the fifth UE 815. The fifth UE 815 may be connected to the fifth satellite 805. For example, the fifth satellite 805 can provide a second cell. The fifth UE 815 may be connected on the second cell. The first UE 811 can be located within the first footprint 821 which is the coverage area of the first satellite 801. The fifth UE 815 can be located within the fifth footprint 825 which is the coverage area of the fifth satellite 805. Since the location of the user of the first UE 811 is geographically significantly separated from the location of the user of the fifth UE 815, a signal path using an ISL can be utilized.

[0089] The first satellite 801 can be connected to the second satellite 802. The second satellite 802 can be connected to the third satellite 803. The third satellite 803 can be connected to the fourth satellite 804. The fourth satellite 804 can be connected to the fifth satellite 805. A signal path can be formed in the order of the first satellite 801, the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805. A link between the first satellite 801 and the fifth satellite 805 (hereinafter, satellite link or satellite relay link) can be generated through relays in the order of the first satellite 801, the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805. UEs (the first UE 811, the fifth UE 815) located at completely different positions (e.g., the first footprint 821, the fifth footprint 825) can generate a satellite link through the procedures according to the embodiments of the present disclosure.

[0090] When the first UE 811 enters the first cell of the first satellite 801, the position of the first UE 811 can be registered with the HLR (Home Location Register) or AMF (e.g., AMF 640) of the NTN network. When the fifth UE 815 enters the second cell of the fifth satellite 805, the position of the fifth UE 815 can be registered with the HLR or AMF (e.g., AMF 640) of the NTN network. The position of the first UE 811 can be managed by the first satellite 801 or a core network entity connected to the first satellite 801 through a TAU procedure or an exchange procedure between upper node entities. The position of the fifth UE 815 can be managed by the fifth satellite 805 or a core network entity connected to the fifth satellite 805 through a TAU procedure or a procedure between upper node entities.

[0091] According to an embodiment, to identify the area where the first UE 811 is located, the identification information of the first footprint 821 (e.g., footprint ID #1), the identification information of the first satellite 801 (e.g., satellite ID #1), and the beam identification information of the first satellite 801 (e.g., Spotbeam ID #1) can be used. To identify the area where the fifth UE 815 is located, the identification information of the fifth footprint 825 (e.g., footprint ID #5), the identification information of the fifth satellite 805 (e.g., satellite ID #5), and the beam identification information of the fifth satellite 805 (e.g., Spotbeam ID #5) can be used.

[0092] According to an embodiment, a plurality of satellites (e.g., the second satellite 802, the third satellite 803, and the fourth satellite 804) that can form a satellite link between the first satellite 801 and the fifth satellite 805 can be used. For example, the first adjacent satellite adjacent to the first satellite 801 can be identified. Among the first adjacent satellites, the second satellite 802 can be identified. The second adjacent satellite adjacent to the second satellite 802 can be identified. Among the second adjacent satellites, the third satellite 803 can be identified. The third adjacent satellite adjacent to the third satellite 803 can be identified. Among the third adjacent satellites, the fourth satellite 804 can be identified. The fourth adjacent satellite adjacent to the fourth satellite 804 can be identified. Among the fourth adjacent satellites, the fifth satellite 805 can be identified. The plurality of satellites that form a satellite link between the first satellite 801 and the fifth satellite 805 can be determined by various entities. For example, the plurality of satellites can be determined by the master satellite within the satellite group. The master satellite can perform route setting between satellites. For example, the plurality of satellites can be determined by the AMF (e.g., AMF 640). The AMF can identify the plurality of satellites that form a satellite link through a route selection algorithm among the plurality of satellites related to the first satellite 801 and the fifth satellite 805. For example, each of the plurality of satellites can be determined by the individual satellite that forms a route. The second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805 can be identified by the first satellite 801, the second satellite 802, the third satellite 803, and the fourth satellite 804, respectively.

[0093] The first UE 811 can request a call connection with the fifth UE 815 on the first cell of the first satellite 801. The first UE 811 is the calling device, and the fifth UE 815 can correspond to the called device. The first UE 811 can transmit a request message for call connection to the first satellite 801. The first satellite 801 can determine whether it is possible to set up a direct link from the first satellite 801 to the fifth satellite 805 in response to the request message. The first satellite 801 can be referred to as the source satellite. The fifth satellite 805 can be referred to as the destination satellite. The direct link refers to a link in which the source satellite (e.g., the first satellite 801) and the destination satellite (e.g., the fifth satellite 805) are directly connected without the intervention of other satellites (i.e., without the relay of other satellites).

[0094] For example, it may be possible to set up a direct link from the first satellite 801 to the fifth satellite 805. A list of satellites adjacent to the first satellite 801 can be identified. The first satellite 801 can determine whether the fifth satellite 805 is included in the list. If the fifth satellite 805 is included in the list, the first satellite 801 can determine that it is possible to set up a direct link from the first satellite 801 to the fifth satellite 805. The first satellite 801 can transmit a link setup request message to the fifth satellite 805. The fifth satellite 805 can transmit a link setup response message to the first satellite 801. A link can be established between the first satellite 801 and the fifth satellite 805.

[0095] For example, it may be difficult to set up a direct link from the first satellite 801 to the fifth satellite 805. A list of satellites adjacent to the first satellite 801 can be identified. The first satellite 801 can determine whether the fifth satellite 805 is included in the list. If the fifth satellite 805 is not included in the list, the first satellite 801 can determine that it is impossible to set up a direct link from the first satellite 801 to the fifth satellite 805. The first satellite 801 can identify the second satellite 802 among the satellites included in the list. The first satellite 801 can transmit a link setup request message to the second satellite 802. The second satellite 802 can transmit a link setup response message to the first satellite 801. A link can be established between the first satellite 801 and the second satellite 802. The first satellite 801 can transmit an instruction message for call connection between the first UE 811 and the fifth UE 815 to the second satellite 802 through the link. By repeating such a procedure, a link can be established between the second satellite 802 and the third satellite 803. The second satellite 802 can transmit an instruction message for call connection between the first UE 811 and the fifth UE 815 to the third satellite 803 through the link. By repeating such a procedure, a link can be established between the third satellite 803 and the fourth satellite 804. The third satellite 803 can transmit an instruction message for call connection between the first UE 811 and the fifth UE 815 to the fourth satellite 804 through the link. By repeating such a procedure, a link can be established between the fourth satellite 804 and the fifth satellite 805. The fourth satellite 804 can transmit an instruction message for call connection between the first UE 811 and the fifth UE 815 to the fifth satellite 805 through the link. Through the established links, a satellite link from the first satellite 801 to the fifth satellite 805 can be formed.

[0096] After the satellite link from the first satellite 801 is formed, the fifth satellite 805 can transmit a signal to the fifth terminal 815 within the fifth footprint 825. The signal can be a paging signal, a wake-up signal, or an incoming request signal. In response to the signal, the fifth terminal 815 can perform a call setup procedure with the fifth satellite 805. When the call setup procedure between the fifth terminal 815 and the fifth satellite 805 is completed, the first terminal 811 can communicate with the fifth terminal 815.

[0097] FIG. 9 illustrates an example of signaling using an ISL. FIG. 9 describes a situation where it is difficult to establish a direct link between the first UE 811 and the fifth UE 815. A link is established between the first UE 811 and the second UE 812, and an indication message for call connection can be transmitted through the link. As an example, when all the satellites are regenerative satellites, the interface between the satellites can be an XN interface. The indication message can be transmitted on the XN interface.

[0098] Referring to FIG. 9, in operation 901, the first satellite 801 can transmit an indication message to the second satellite 802. For example, the indication message can be configured for call connection between the first UE 811 and the fifth UE 815.

[0099] Although not shown in FIG. 9, the first satellite 801 can receive a request message for call connection from the first UE 811. The request message can include identification information of the first UE 811 corresponding to the caller (e.g., UE ID, GUTI (global unite temporary identifier), IMSI (International Mobile Subscriber Identity)), identification information of the fifth UE 815 corresponding to the callee (e.g., UE ID, GUTI, IMSI), identification information of the serving cell of the first UE 811, and / or identification information for the first satellite 801 that provides the serving cell of the first UE 811.

[0100] In response to the request message, the first satellite 801 can identify the target satellite. The first satellite 801 can obtain information about the area where the fifth UE 815 is located through the identification information of the fifth UE 815. The first satellite 801 can identify the fifth satellite 805 that provides the service cell of the fifth UE 815 from the information about the area. The first satellite 801 can identify the fifth satellite 805 as the target satellite. According to an embodiment, the first satellite 801 can generate an indication message including information about the target satellite (DP: identification information about the fifth satellite 805). The entity that identifies the target satellite may be performed by a separate network entity (e.g., AMF or HLR server) connected to the first satellite 801 or the master satellite within the satellite group instead of the first satellite 801. According to an embodiment, the indication message may include the identification information of the first UE 811, the identification information of the fifth UE 815, the identification information of the first satellite 801 which is the source satellite, the identification information of the fifth satellite 805 which is the target satellite, information about the first cell provided by the first satellite 801 (e.g., PCI (physical cell identity), CGI (cell global identity)), and / or information about the second cell provided by the fifth satellite 805 (e.g., PCI, CGI).

[0101] After identifying the destination satellite, the first satellite 801 can determine the route from the first satellite 801, which is the source satellite, to the fifth satellite 805, which is the destination satellite. The route can include a plurality of satellites. According to one embodiment, the first satellite 801 can generate an instruction message including information about the satellites in the route. The entity determining the route may be performed by a separate network entity (e.g., AMF or HLR server) connected to the first satellite 801 or the master satellite within the satellite group instead of the first satellite 801. If the route is set by an external network entity, the first satellite 801 can generate an instruction message including information about the satellites in the set route. However, satellites not only continuously move along their orbits, but also the orbits are not parallel to each other. So, as time passes, the optimal link in three-dimensional space can change. Therefore, when receiving a request message for the first call connection, instead of setting the entire satellite route, a solution of providing star-shaped information and / or celestial ephemeris information for link establishment to adjacent satellites can be considered. For example, the celestial ephemeris information can include position-velocity information and orbital information. The position-velocity information respectively indicates a position vector and a velocity vector in the XYZ coordinate system, and the orbital information indicates the semi-major axis of the orbit, eccentricity, periapsis, hardness, and / or inclination.

[0102] According to one embodiment, the first satellite 801 can generate an instruction message including direction information. The first satellite 801 can obtain the star-shaped information and / or celestial ephemeris information of the fifth satellite 805. The first satellite 801 can determine the direction information based on the celestial ephemeris information of the first satellite 801 and the celestial ephemeris information of the fifth satellite 805. For example, the first satellite 801 can determine the direction between the space where the first satellite 801 is located and the space where the fifth satellite 805 is located at a specific time. Based on the direction, the satellites in the satellite route (e.g., the second satellite 802, the third satellite 803, and the fourth satellite 804) can be identified. For example, the direction can be obtained through the difference between the position vector of the first satellite 801, which is the source satellite, and the position vector of the fifth satellite 805, which is the destination satellite, in the XYZ coordinate system. The direction can correspond to a direction vector expressed in the XYZ coordinate system.

[0103] The first satellite 801 can transmit the generated instruction message to the adjacent second satellite 802. For example, the second satellite 802 can be instructed by an external network entity (AMF, HLR server, or master satellite within the satellite group). As another example, the second satellite 802 can be a satellite corresponding to a specific direction (e.g., the direction from the first satellite 801 to the fifth satellite 805) among the adjacent satellites adjacent to the first satellite 801.

[0104] Although the instruction message between the first satellite 801 and the second satellite 802 is illustrated in FIG. 9, the embodiments of the present disclosure are not limited thereto. All transmissions of the aforementioned instruction message can be applied as long as it is an ISL. For example, the description of the instruction message can also be applied to the instruction message between the second satellite 802 and the third satellite 803. For example, the description of the instruction message can also be applied to the instruction message between the third satellite 803 and the fourth satellite 804. For example, the description of the instruction message can also be applied to the instruction message between the fourth satellite 804 and the fifth satellite 805. As a non-limiting example, the first satellite 801 can determine the number of hops. The satellite link from the first satellite 801 to the fifth satellite 805 can be understood as forming a relay link between satellites. The more satellites there are in the satellite link, the more difficult it may be to ensure stable communication performance. Therefore, the first satellite 801 can generate an instruction message including the number of hops of the satellite link. Each time the instruction message passes through each link of the satellite path, the number of hops can decrease. For example, if the number of hops in the instruction message of the first satellite 801 is 5, the number of hops in the instruction message transmitted to the second satellite 802 and the third satellite 803 can be 4.

[0105] According to one embodiment, the instruction message can include at least one of the items listed in the following table. The instruction message can be transmitted through an inter-satellite link (e.g., ISL), that is, from a specific satellite to another satellite.

[0106]

Table 4

[0107] Figure 10 illustrates an example of satellite change by orbital movement.

[0108] Referring to Figure 10, the first satellite 801 can move along the designated orbit 1007. For example, the first satellite 801 can move along the designated orbit 1007 in the clockwise direction. Currently, the first satellite 801 provides services to the first footprint 821 through the first beam 1077. However, after a certain period of time, it may be difficult for the first satellite 801 to provide services to the first footprint 821 any more. Another satellite (e.g., the sixth satellite 1001) can provide services to the first footprint 821. Therefore, the first satellite 801 can provide not only information about the first satellite 801 but also information about the satellites following the first satellite 801 (hereinafter referred to as the following satellites) (e.g., the sixth satellite 1001) to the second satellite 802. According to one embodiment, the instruction message can include information about the following satellites related to the first satellite 801.

[0109] Although not shown in Figure 10, similar to the source satellite, the destination satellite can also move along the designated orbit. Therefore, after a certain period of time, the fifth satellite 805 may not need to provide services to the fifth footprint 825 any more. After the certain period of time elapses, other satellites following the fifth satellite 805 can provide services to the fifth footprint 825.

[0110] Each satellite can know the celestial calendar information of other satellites. Therefore, a satellite can know at which position another satellite is in service during a specific time period. For example, the first satellite 801 can identify the subsequent satellites of each of the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805 that form a satellite link. The first satellite 801 can identify at least one first satellite that follows the first satellite 801. The indication message can include information about the at least one first satellite, the beam ID information of each satellite of the at least one first satellite, the time each satellite of the at least one first satellite stays in the corresponding footprint, and the cell information of each satellite of the at least one first satellite (for example, in the case of a transparent payload, the cell is maintained by a switch-over, but in the case of a reproduction payload, the cell is changed). The first satellite 801 can identify at least one second satellite that follows the second satellite 802. The indication message can include information about the at least one second satellite, the beam ID information of each satellite of the at least one second satellite, the time each satellite of the at least one second satellite stays in the corresponding footprint, and the cell information of each satellite of the at least one second satellite (for example, in the case of a transparent payload, the cell is maintained by a switch-over, but in the case of a reproduction payload, the cell is changed). The first satellite 801 can identify at least one third satellite that follows the third satellite 803. The indication message can include information about the at least one third satellite, the beam ID information of each satellite of the at least one third satellite, the time each satellite of the at least one third satellite stays in the corresponding footprint, and the cell information of each satellite of the at least one third satellite (for example, in the case of a transparent payload, the cell is maintained by a switch-over, but in the case of a reproduction payload, the cell is changed). The first satellite 801 can identify at least one fourth satellite that follows the fourth satellite 804.The indication message can include information about the at least one fourth satellite, beam ID information of each satellite of the at least one fourth satellite, the time each satellite of the at least one fourth satellite stays in the corresponding footprint, and cell information of each satellite of the at least one fourth satellite (for example, in the case of a transparent payload, the cell is maintained by switch-over, while in the case of a reproduction payload, the cell is changed). The first satellite 801 can identify at least one fifth satellite following the fifth satellite 805. The indication message can include information about the at least one fifth satellite, beam ID information of each satellite of the at least one fifth satellite, the time each satellite of the at least one fifth satellite stays in the corresponding footprint, and cell information of each satellite of the at least one fifth satellite (for example, in the case of a transparent payload, the cell is maintained by switch-over, while in the case of a reproduction payload, the cell is changed). The entity that identifies the subsequent satellite may be performed by a separate network entity (such as an AMF or HLR server) connected to the first satellite 801 or a master satellite within the satellite group instead of the first satellite 801.

[0111] In FIG. 10, it was described that due to the orbital movement of the satellite, the instruction message transmitted between satellites must include information for the subsequent satellite. Depending not only on the orbital movement of the satellite but also on the type of satellite and the capabilities of the terminal, various information can be included in the instruction message. According to one embodiment, the instruction message can include information regarding the orbital type of the satellite included in the path. For example, the instruction message can include information regarding the orbital type of the source satellite (e.g., the first satellite 801). The orbital type can indicate LEO, MEO, or GEO. For example, the instruction message can include information regarding the orbital type of the destination satellite (e.g., the fifth satellite 805). The orbital type can indicate LEO, MEO, or GEO. According to one embodiment, the instruction message can include information regarding the satellite type. The satellite type can indicate whether it is a reproductive payload or a transparent payload. According to one embodiment, the instruction message can include information regarding the speed of the satellite. For example, the speed of the satellite can be indicated through the velocity vector of each axis in the XYZ coordinate system as indicated by celestial ephemeris information. According to one embodiment, the instruction message can include information regarding the number of beams per satellite. Even for the same satellite, various coverages can be supported through different beams. The instruction message can include information regarding the number of beams provided by the satellite and / or information for each beam (e.g., beam ID).

[0112] According to one embodiment, the instruction message can include at least one of the items listed in the following table. The items can be defined for each satellite. The instruction message can be transmitted through an inter-satellite link (e.g., ISL), that is, from a specific satellite to another satellite.

[0113]

Table 5

[0114] As a non-limiting example, at least one of the items in Table 5 may be included in and used in the indication message together with at least one of the items in Table 4.

[0115] FIG. 11 illustrates an example of route setting using an ISL. Hereinafter, the route setting will be described as being performed by a source satellite (e.g., the first satellite 801), but embodiments of the present disclosure are not limited thereto. The route setting may be performed by a separate network entity (e.g., NTN gateway 223, NTN gateway 630, AMF 640, HLR server) that manages the satellites, or may be performed by a master satellite that controls other satellites among the satellites.

[0116] Referring to FIG. 11, the first satellite 801 can identify a first set 1102 of adjacent satellites adjacent to the first satellite 801. The first satellite 801 can identify the second satellite 802 among the satellites of the first set 1102. For example, the first satellite 801 can identify the second satellite 802 among the satellites of the first set 1102 based on the time the satellite stays in the footprint, the direction information between the source satellite and the destination satellite, the beam information per satellite, and the ephemeris information per satellite (e.g., position-velocity information and orbit information). The second satellite 802 can identify a second set 1103 of adjacent satellites adjacent to the second satellite 802. The second satellite 802 can identify the third satellite 803 among the satellites of the second set 1103. For example, the second satellite 802 can identify the third satellite 803 among the satellites of the second set 1103 based on the time the satellite stays in the footprint, the direction information between the source satellite and the destination satellite, the beam information per satellite, and the ephemeris information per satellite (e.g., position-velocity information and orbit information). The third satellite 803 can identify a third set 1104 of adjacent satellites adjacent to the third satellite 803. The third satellite 803 can identify the fourth satellite 804 among the satellites of the third set 1104. For example, the third satellite 803 can identify the fourth satellite 804 among the satellites of the third set 1104 based on the time the satellite stays in the footprint, the direction information between the source satellite and the destination satellite, the beam information per satellite, and the ephemeris information per satellite (e.g., position-velocity information and orbit information). The fourth satellite 804 can identify a fourth set (not shown) of adjacent satellites adjacent to the fourth satellite 804. The fourth satellite 804 can identify the fifth satellite 805 among the satellites of the fourth set. For example, the fourth satellite 804 can identify the fifth satellite 805 among the satellites of the fourth set based on the time the satellite stays in the footprint, the direction information between the source satellite and the destination satellite, the beam information per satellite, and the ephemeris information per satellite (e.g., position-velocity information and orbit information).

[0117] In FIG. 11, an example is described in which satellites between the first satellite 801 and the fifth satellite 805 set satellite routes according to a certain algorithm. As a non-limiting example, the route setting may be set by an external network entity (e.g., NTN gateway 223, NTN gateway 630, AMF 640, HLR server, or master satellite within a satellite group). The first satellite 801 can transmit a message for requesting route setting to the external network entity. For example, since AMF 640 knows the celestial ephemeris information for each satellite, it can identify the position information of the corresponding satellite in a specific time period. AMF 640 can determine a list of satellites connecting the first satellite 801 and the fifth satellite 805. AMF 640 can transmit information about the list to each satellite. For example, AMF 640 can transmit information about the second satellite 802 to the first satellite 801. AMF 640 can transmit information about the third satellite 803 to the second satellite 802. AMF 640 can transmit information about the fourth satellite 804 to the third satellite 803. AMF 640 can transmit information about the fifth satellite 805 to the fourth satellite 804. As another example, AMF 640 can transmit information about the list of route satellites to each of the first satellite 801, the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805.

[0118] As a non-limiting example, the satellite route may be set in an ad-hoc network manner. In the ad-hoc network manner, the network topology can be dynamically formed through autonomous signaling between satellites. For example, the first satellite 801 can broadcast an instruction message. A satellite (e.g., the second satellite 802) that receives the instruction message can broadcast the instruction message. By repeatedly transmitting the instruction message through the links between satellites, the instruction message can reach the fifth satellite 805, which is the destination satellite. Due to the ad-hoc network manner, the instruction message can further include information about the number of hops.

[0119] According to an embodiment, the satellite selection criteria for route setting can include the following elements. The inter-satellite distance and the communication range, the current traffic load of each satellite, the predicted orbital movement path of the satellite, and the communication delay time can be considered. Based on such criteria, an optimal route can be selected.

[0120] If the ISL setting on the selected route fails, the following alternative procedures can be performed. First, the next adjacent satellite in the priority order can be selected. Subsequently, the re-exploration of the alternative route can be performed. If necessary, a detour route through the terrestrial gateway can be set.

[0121] FIG. 12 illustrates an example of the RRC configuration for route indication.

[0122] Referring to FIG. 12, the first satellite 801 can transmit RRC configuration information to the first UE 811. According to an embodiment, the RRC configuration information 1201 can include information for the first satellite 801 and subsequent satellites with respect to the first satellite 801. For example, the RRC configuration information 1201 can include celestial ephemeris information for each satellite. According to an embodiment, the RRC configuration information 1201 can be provided through the SI message of the SIB (system information block). For example, the RRC configuration information 1201 can have the following format.

[0123] [Table 6]

[0124] "ntn-Config" indicates the parameters for connecting to the radio network through NTN access, and the following table (e.g., [Table 7]) can be referred to. "t-service" can indicate the time information for the point in time when the service provided by the cell currently in charge for the area provided through the NTN quasi-Earth fixed system is interrupted. "referenceLocation" indicates the reference position of the service cell provided through the NTN quasi-Earth fixed system. "distanceThresh" indicates the distance from the reference position of the service cell and can be used for position-based measurements even in the RRC IDLE or RRC INACTIVE state. "ntn-NeighCellConfigList" can indicate the information for adjacent cells for the cells provided through satellites (e.g., satellite 260, satellite 620).

[0125]

Table 7

[0126] "epochTime" indicates the epoch time of the NTN assistance information. When provided in detail through the SIB or through dedicated signaling, the epoch time indicates the start time of the DL subframe and can display the number of the subframe signaled together with the SFN (system frame number) and the assistance information. As a non-limiting example, for higher granularity, "epochTime" can further include an IE (information element) that indicates a symbol in addition to the subframe. The said IE can indicate one of 0 to 13 and can indicate one of the 14 symbols.

[0127] 「ntn-UlSyncValidityDuration」 is the validity duration for the auxiliary information (e.g., ephemeris information, common TA parameters) set by the network. In other words, the period indicates the maximum time during which the support information can be applied without obtaining new NTN support information. The time period can start from the epoch time. 「cellSpecificKoffset」 indicates the scheduling offset used for the timing relationships modified for NTN. 「kmac」 indicates the scheduling offset used when the downlink timing and the uplink timing do not match. 「ta-Info」 can include information for TA (timing advance). The information for TA can include 「ta-Common」 which is the common TA controlled by the network, 「ta-CommonDrift」 which indicates the drift rate of the common TA, and 「ta-CommonDriftVariant」 which indicates the variation of the drift rate. 「ntn-PolarizationDL」 and 「ntn-PolarizationUL」 indicate the polarization information in DL and UL respectively. 「ephemerisInfo」 indicates the ephemeris information, and the following table (e.g., [Table 8]) can be exemplified. 「ta-Report」 indicates that TA reporting is activated during RRC connection establishment, RRC connection resume, and RRC connection re-establishment.

[0128]

Table 8

[0129] "positionX", "positionY", and "positionZ" respectively represent the position state vectors of ECEF (earth-centered and earth-fixed) in the xyz coordinate system. The unit is meter, and one step represents 1.3 m (meter). For example, the actual value can be the field value * 1.3. "velocityX", "velocityY", and "velocityZ" respectively represent the velocity state vectors of ECEF in the xyz coordinate system. One step represents 0.06 m / s (meter / seconds). For example, the actual value can be the field value * 0.06. "semiMajorAxis" is the semi-major axis of the orbit, "eccentricity" is the eccentricity, "periapsis" is the periapsis, "longitude" is the hardness, "inclination" is the inclination, and "meanAnomaly" represents the ratio of the elliptical orbit period elapsed after an object orbiting the orbit passes the periapsis above the mean (mean anomaly).

[0130] According to one embodiment, the RRC configuration information can include information about a list of satellites (i.e., satellites of satellite links) on the path set from a source satellite (e.g., the first satellite 801) to a destination satellite (e.g., the fifth satellite 805). For example, the RRC configuration information can include a list including the first satellite 801, the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805. The RRC configuration information can be provided to the first UE 811 as a response to a call connection request message of the first UE 811.

[0131] According to one embodiment, the RRC configuration information can include information about the duration of a call connection with the fifth UE 815 established through the satellite link between the first satellite 801 and the fifth satellite 805. Satellites not only move continuously along their orbits, but since each orbit is not parallel to each other, the optimal link in three-dimensional space can change over time. Therefore, the duration for the corresponding path can be limited. The RRC configuration information can include information about the effective time of the corresponding satellite link.

[0132] FIG. 13 illustrates an example of components of a satellite (e.g., satellite 260, satellite 620). Terms such as “... unit” and “... device” used hereinafter mean a unit that processes at least one function or operation, which can be embodied by hardware, software, or a combination of hardware and software.

[0133] Referring to FIG. 13, satellite 620 can include a transceiver 1301, a processor 1303, and a memory 1305. The transceiver 1301 performs a function for transmitting and receiving signals through a wireless channel. For example, the transceiver 1301 upwardly converts a baseband signal into an RF band signal and then transmits it through an antenna, and downwardly converts an RF band signal received through the antenna into a baseband signal. For example, the transceiver 1301 can include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0134] The transceiver 1301 can include a number of transmission and reception paths. Further, the transceiver 1301 can include an antenna unit. The transceiver 1301 can include at least one antenna array composed of a number of antenna elements. On the hardware side, the transceiver 1301 can be composed of digital circuits and analog circuits (e.g., RFIC (radio frequency integrated circuit)). Here, the digital circuits and analog circuits can be embodied in one package. Also, the transceiver 1301 can include a number of RF chains. The transceiver 1301 can perform beamforming. The transceiver 1301 can apply a beamforming weight value to a signal in order to impart a directivity according to the settings of the processor 1303 to the signal to be transmitted and received. According to one embodiment, the transceiver 1301 can include an RF (radio frequency) block (or RF unit).

[0135] The transceiver 1301 can transmit and receive signals over a radio access network. For example, the transceiver 1301 can transmit a downlink signal. The downlink signal can include a synchronization signal (SS), a reference signal (RS) (e.g., CRS (cell-specific reference signal), DM (demodulation)-RS), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), a configuration message, control information, or downlink data, etc. Also, for example, the transceiver 1301 can receive an uplink signal. The uplink signal can include a random access related signal (e.g., a random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), a reference signal (e.g., SRS (sounding reference signal), DM-RS), or a power headroom report (PHR), etc. Although only the transceiver 1301 is illustrated in FIG. 13, in other embodiments, the satellite 620 can include two or more RF transceivers.

[0136] Processor 1303 controls the overall operation of satellite 620. Processor 1303 may be referred to as a control unit. For example, processor 1303 transmits and receives signals through transceiver 1301. Also, processor 1303 records data in and reads data from memory 1305. And processor 1303 can perform the functions of a protocol stack required by a communication standard. Although only processor 1303 is illustrated in FIG. 13, in other embodiments, satellite 620 may include two or more processors. Processor 1303 may be a set of instruction words or code stored in memory 1305, a storage space that at least temporarily resides in processor 1303 or stores instruction words / code, or may be part of the circuitry that constitutes processor 1303. Also, processor 1303 may include various modules for performing communication. Processor 1303 can control satellite 620 to perform operations according to the embodiments.

[0137] Memory 1305 stores data such as basic programs, application programs, and setting information for the operation of satellite 620. Memory 1305 may be referred to as a storage unit. Memory 1305 may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. And memory 1305 provides the data stored upon the request of processor 1303. According to one embodiment, memory 1305 may include memory for conditions, instructions, or setting values related to the SRS transmission method.

[0138] FIG. 14 illustrates an example of the components of a terminal (e.g., UE610). The terminal is exemplified by UE610. UE610 can establish a connection to a gNB (e.g., gNB120) that provides NR access through NTN.

[0139] Referring to FIG. 14, UE610 may include at least one processor 1401, at least one memory 1403, and at least one transceiver 1405. Hereinafter, the components are described in the singular, but the implementation of multiple components or sub-components is not excluded.

[0140] Processor 1401 controls the overall operation of UE 610. For example, processor 1401 records data in and reads data from memory 1403. For example, processor 1401 transmits and receives signals through transceiver 1405. Although one processor is illustrated in FIG. 14, embodiments of the present disclosure are not limited thereto. UE 610 may include at least one processor to implement embodiments of the present disclosure. Processor 1401 may be referred to as a control unit or control means. According to an embodiment, processor 1401 can control UE 610 to perform at least one of the operations or methods according to embodiments of the present disclosure.

[0141] Memory 1403 can store data such as basic programs, application programs, and setting information for the operation of UE 610. Memory 1403 can store various data used by at least one component (e.g., transceiver 1405, processor 1401). The data may include, for example, software and input data or output data for related instructions. Memory 1403 may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. And memory 1403 can provide the data stored at the request of processor 1401.

[0142] Transceiver 1405 performs a function for transmitting and receiving signals through a wireless channel. For example, transceiver 1405 performs a conversion function between a baseband signal and a bit sequence according to the physical layer standard of the system. For example, when transmitting data, transceiver 1405 generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, transceiver 1405 restores the received bit sequence through demodulation and decoding of the baseband signal. Also, transceiver 1405 upwardly converts the baseband signal into an RF (radio frequency) band signal and then transmits it through an antenna, and downwardly converts the RF band signal received through the antenna into a baseband signal.

[0143] For this purpose, the transceiver 1405 can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog convertor), an ADC (analog to digital convertor), etc. Also, the transceiver 1405 can include a number of transmission and reception paths. Consequently, the transceiver 1405 can include at least one antenna array composed of a number of antenna elements. On the hardware side, the transceiver 1405 can be composed of a digital unit and an analog unit, and the analog unit can be composed of a number of sub-units according to the operating power, operating frequency, etc.

[0144] As described above, the transceiver 1405 transmits and receives signals. Accordingly, the transceiver 1405 can be referred to as a "transmission unit", a "reception unit", or a "transceiver unit". Also, in the following description, the transmission and reception performed through a wireless channel, a backhaul network, an optical cable, Ethernet, or other wired paths are used in the sense that the transceiver 1405 performs the processing as described above. According to one embodiment, the transceiver 1405 can provide an interface for communicating with other nodes in the network. That is, the transceiver 1405 can convert a bit string transmitted from the UE 610 to other nodes, such as other connected nodes, other base stations, upper nodes, a core network, etc., into a physical signal, and convert a physical signal received from other nodes into a bit string.

[0145] In describing embodiments of the present disclosure, terms and messages defined by 3GPP are used to describe messages between a satellite (e.g., satellite 620) and a terminal (e.g., UE 610). However, embodiments of the present disclosure are not limited thereto. Of course, terms and messages having a technical meaning equivalent to the terms and messages described above may be used as an alternative. In addition, as the satellite, not only gNB, gNB-CU, and gNB-DU, but also gNB-CU-CP (control plane) (e.g., C-plane in FIG. 3a) and gNB-CU-UP (user plane) (e.g., U-plane in FIG. 3b) may be used. Further, not only is the satellite used as a base station (e.g., gNB) or a part of the base station (e.g., DU), but also a core network entity (e.g., AMF 235) connected to the base station may be implemented by the satellite. For example, communication between a satellite operating as AMF 235 and satellite 620 may be defined. For example, a logical node including AMF 235 and gNB 120 may be implemented in one satellite. Through network virtualization, by being implemented in software, separate logical nodes may be arranged within one hardware satellite.

[0146] In an embodiment, a satellite device for providing NTN access is provided. The device can include a memory containing instructions, at least one processor, and at least one transceiver. When the instructions are executed by the at least one processor, the device receives a request message for call connection from a terminal through the at least one transceiver, identifies a target satellite corresponding to the target terminal of the request message, determines whether a direct link to the target satellite is possible, and if a direct link to the target satellite is possible, transmits an instruction message for call connection between the terminal and the target terminal to the target satellite through the at least one transceiver. If a direct link to the target satellite is not possible, it can identify a second satellite capable of forming a direct link with the satellite and cause the instruction message to be transmitted to the second satellite through the at least one transceiver.

[0147] For example, the instruction message can include at least one of the identification information of the satellite, the identification information of the target satellite, the identification information of the terminal, the identification information of the target terminal, the beam information of the satellite, or the beam information of the target satellite.

[0148] For example, the instruction message can include direction information indicating a direction vector from the satellite to the target satellite.

[0149] For example, the instruction message can include a list of satellites on the path to the satellite and the target satellite.

[0150] For example, the instruction message can include information about a first successor satellite providing services to a first footprint of the satellite and information about a second successor satellite providing services to a second footprint of the target satellite.

[0151] For example, the information for the first subsequent satellite can include at least one of the identification information of the first subsequent satellite, the beam information of the first subsequent satellite, the cell information of the first subsequent satellite, or the information regarding the time the first subsequent satellite stays within the first footprint of the satellite. The information for the second subsequent satellite can include at least one of the identification information of the second subsequent satellite, the beam information of the second subsequent satellite, the cell information of the second subsequent satellite, or the information regarding the time the second subsequent satellite stays within the second footprint of the target satellite.

[0152] For example, the request message can include the identification information of the terminal and the identification information of the target terminal.

[0153] In an embodiment, a method performed by a satellite for providing NTN access is provided. The method includes receiving a request message for call connection from a terminal, identifying a target satellite corresponding to the target terminal of the request message, determining whether a direct link to the target satellite is possible, if a direct link to the target satellite is possible, transmitting an instruction message for call connection between the terminal and the target terminal to the target satellite, if a direct link to the target satellite is not possible, identifying a second satellite capable of forming a direct link with the satellite, and transmitting the instruction message to the second satellite.

[0154] For example, the instruction message can include at least one of the identification information of the satellite, the identification information of the target satellite, the identification information of the terminal, the identification information of the target terminal, the beam information of the satellite, or the beam information of the target satellite.

[0155] For example, the instruction message can include direction information indicating a direction vector from the satellite to the target satellite.

[0156] For example, the instruction message can include a list of satellites on the route to the satellite and the target satellite.

[0157] For example, the instruction message can include information about a first subsequent satellite that provides services to the first footprint of the satellite and information about a second subsequent satellite that provides services to the second footprint of the target satellite.

[0158] For example, the information about the first subsequent satellite can include at least one of the identification information of the first subsequent satellite, the beam information of the first subsequent satellite, the cell information of the first subsequent satellite, or the information about the time the first subsequent satellite stays in the first footprint of the satellite. The information about the second subsequent satellite can include at least one of the identification information of the second subsequent satellite, the beam information of the second subsequent satellite, the cell information of the second subsequent satellite, or the information about the time the second subsequent satellite stays in the second footprint of the target satellite.

[0159] For example, the request message can include the identification information of the terminal and the identification information of the target terminal.

[0160] In an embodiment, a non-transitory storage medium is provided. It can include a memory containing instructions. When the instructions are executed by a processor of a satellite, the satellite receives a request message for a call connection from a terminal, identifies a target satellite corresponding to the target terminal of the request message, determines whether a direct link to the target satellite is possible, and if a direct link to the target satellite is possible, transmits an instruction message for a call connection between the terminal and the target terminal to the target satellite. If a direct link to the target satellite is not possible, it can identify a second satellite with which a direct link can be formed and cause the second satellite to transmit through the instruction message.

[0161] For example, the instruction message can include at least one of the identification information of the satellite, the identification information of the target satellite, the identification information of the terminal, the identification information of the target terminal, the beam information of the satellite, or the beam information of the target satellite.

[0162] For example, the instruction message can include direction information indicating a direction vector from the satellite to the target satellite.

[0163] For example, the instruction message can include a list of satellites on the route from the satellite to the target satellite.

[0164] For example, the instruction message can include information about a first subsequent satellite that provides services to the first footprint of the satellite and information about a second subsequent satellite that provides services to the second footprint of the target satellite.

[0165] For example, the information about the first subsequent satellite can include at least one of the identification information of the first subsequent satellite, the beam information of the first subsequent satellite, the cell information of the first subsequent satellite, or information about the time the first subsequent satellite stays in the first footprint of the satellite. The information about the second subsequent satellite can include at least one of the identification information of the second subsequent satellite, the beam information of the second subsequent satellite, the cell information of the second subsequent satellite, or information about the time the second subsequent satellite stays in the second footprint of the target satellite.

[0166] For example, the request message can include the identification information of the terminal and the identification information of the target terminal.

[0167] The method according to the claims or embodiments described in the specification of the present disclosure can be implemented in the form of hardware, software, or a combination of hardware and software.

[0168] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to perform the methods according to the embodiments described in the claims or the specification of the present disclosure.

[0169] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or it may be stored in a memory composed of some or all of these combinations. Also, each constituent memory may include a large number.

[0170] Also, the program can be stored in an attachable storage device that can be accessed through a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a communication network composed of a combination of these. Such a storage device can be connected to the device that implements the embodiments of the present disclosure through an external port. Also, a separate storage device on the communication network may be connected to the device that implements the embodiments of the present disclosure.

[0171] In the specific embodiments of the present disclosure described above, the components included in the disclosure are represented in singular or plural by the specific embodiments presented. However, the singular or plural expressions are selected to conform to the situations presented for the convenience of explanation, and the present disclosure is not limited to singular or plural components. Even components expressed in plural may be composed of a single one, or even components expressed in singular may be composed of a plurality.

[0172] On the other hand, although the detailed description of the present disclosure has been made with respect to specific embodiments, it goes without saying that various modifications are possible within the scope not departing from the present disclosure.

Claims

1. A satellite device for providing NTN access, comprising: A memory containing instructions; at least one processor; and at least one transceiver; The instructions, when executed by the at least one processor, cause the apparatus to: receiving a request message for a call connection from a terminal through the at least one transceiver; Identifying a destination satellite corresponding to a destination terminal of the request message; determining whether a direct link to the destination satellite is possible; If a direct link to the destination satellite is possible, an instruction message for a call connection between the terminal and the destination terminal is transmitted to the destination satellite through the at least one transceiver; if a direct link to the destination satellite is not possible, identifying a second satellite with which a direct link can be formed with the destination satellite; causing said second satellite to transmit said instruction message via said at least one transceiver.

2. The device of claim 1 , wherein the instruction message includes at least one of an identification information of the satellite, an identification information of the destination satellite, an identification information of the terminal, an identification information of the destination terminal, beam information of the satellite, or beam information of the destination satellite.

3. The apparatus of claim 1 , wherein the instruction message includes direction information indicating a direction vector from the satellite to the destination satellite.

4. The apparatus of claim 1 , wherein the instruction message includes a list of the satellite and a path to the destination satellite.

5. 2. The apparatus of claim 1, wherein the instruction message includes information for a first follower satellite serving a first footprint of the satellite and information for a second follower satellite serving a second footprint of the destination satellite.

6. the information about the first subsequent satellite includes at least one of identification information about the first subsequent satellite, beam information about the first subsequent satellite, cell information about the first subsequent satellite, or information about a time that the first subsequent satellite remains in the first footprint of the satellite; 6. The apparatus of claim 5, wherein the information for the second follower satellite includes at least one of identification information of the second follower satellite, beam information of the second follower satellite, cell information of the second follower satellite, or information regarding the time the second follower satellite remains in the second footprint of the destination satellite.

7. In claim 1, The request message includes identification information of the terminal and identification information of the target terminal.

8. 1. A method performed by a satellite for providing NTN access, comprising: receiving a request message for call connection from a terminal; an operation of identifying a destination satellite corresponding to a destination terminal of the request message; determining whether a direct link to the destination satellite is possible; transmitting, to the destination satellite, an instruction message for a call connection between the terminal and the destination terminal when a direct link to the destination satellite is possible; if a direct link to the destination satellite is not possible, identifying a second satellite with which a direct link can be formed with the destination satellite; The method includes an act of transmitting the instruction message to the second satellite.

9. The method of claim 8, wherein the instruction message includes at least one of the following: identification information of the satellite, identification information of the destination satellite, identification information of the terminal, identification information of the destination terminal, beam information of the satellite, or beam information of the destination satellite.

10. The method of claim 8 , wherein the instruction message includes direction information indicating a direction vector from the satellite to the destination satellite.

11. The method of claim 8 , wherein the instruction message includes a list of the satellite and a path to the destination satellite.

12. 9. The method of claim 8, wherein the instruction message includes information for a first follow-on satellite serving a first footprint of the satellite and information for a second follow-on satellite serving a second footprint of the destination satellite.

13. the information about the first subsequent satellite includes at least one of identification information about the first subsequent satellite, beam information about the first subsequent satellite, cell information about the first subsequent satellite, or information about a time that the first subsequent satellite remains in the first footprint of the satellite; 13. The method of claim 12, wherein the information for the second follower satellite includes at least one of identification information of the second follower satellite, beam information of the second follower satellite, cell information of the second follower satellite, or information regarding the time the second follower satellite remains in the second footprint of the destination satellite.

14. The method of claim 8 , wherein the request message includes identification information of the terminal and identification information of the target terminal.

15. In non-transitory storage media, a memory containing instructions; The instructions, when executed by a processor on a satellite, cause the satellite to: receiving a request message for call connection from a terminal; Identifying a destination satellite corresponding to a destination terminal of the request message; determining whether a direct link to the destination satellite is possible; If a direct link to the destination satellite is possible, transmitting an instruction message to the destination satellite for a call connection between the terminal and the destination terminal; if a direct link to the destination satellite is not possible, identifying a second satellite with which a direct link can be formed with the destination satellite; A non-transitory storage medium that causes the second satellite to transmit the instruction message.

16. The non-transitory storage medium of claim 15, wherein the instruction message includes at least one of identification information of the satellite, identification information of the destination satellite, identification information of the terminal, identification information of the destination terminal, beam information of the satellite, or beam information of the destination satellite.

17. The non-transitory storage medium of claim 15 , wherein the instruction message includes directional information indicating a direction vector from the satellite to the destination satellite.

18. The non-transitory storage medium of claim 15 , wherein the instruction message includes a list of the satellite and satellites along a path to the destination satellite.

19. 16. The non-transitory storage medium of claim 15, wherein the instruction message includes information for a first follow-on satellite serving a first footprint of the satellite and information for a second follow-on satellite serving a second footprint of the destination satellite.

20. the information about the first subsequent satellite includes at least one of identification information about the first subsequent satellite, beam information about the first subsequent satellite, cell information about the first subsequent satellite, or information about a time that the first subsequent satellite remains in the first footprint of the satellite; The non-transitory storage medium of claim 19, wherein the information for the second follower satellite includes at least one of identification information of the second follower satellite, beam information of the second follower satellite, cell information of the second follower satellite, or information regarding the time the second follower satellite remains in the second footprint of the destination satellite.

Images