Apparatus for satellites providing NTN access, method performed by same, and storage medium

Abstract

The invention relates to an apparatus of a satellite providing NTN access, a method performed by the same, and a storage medium. In an embodiment, an apparatus for a satellite providing NTN access is provided. The apparatus includes a memory including instructions, at least one processor, and at least one transceiver. The instructions, when executed by the at least one processor, cause the apparatus to receive a request message for a call connection from a terminal through the at least one transceiver, identify a target satellite corresponding to a target terminal of the request message, determine whether direct link to the target satellite is possible, and, when direct link to the target satellite is possible, send the request message to the at least one transceiver. Sending an indication message for a call connection between the terminal and the target terminal to a target satellite through at least one transceiver, identifying a second satellite capable of forming a direct link with the satellite when the target satellite cannot be directly linked, and sending the indication message to the second satellite through at least one transceiver.

Description

Technical Field

[0001] The present invention 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 instead of ground base stations, and particularly focuses on providing links between satellites. Background Art

[0002] In order to improve the terrestrial network that provides wireless communication systems, non-terrestrial networks are introduced. Non-terrestrial networks can provide communication services in areas where it is difficult to build terrestrial networks or in disaster situations. In addition, due to the recent reduction in satellite launch costs, access network environments can be effectively provided. Summary of the invention

[0003] In an embodiment, a device for providing a satellite for accessing a non-terrestrial network (NTN) is provided. The device may include: a memory including instructions, at least one processor, and at least one transceiver. When the instructions are executed by the at least one processor, the device may perform the following operations: receiving a request message for a call connection from a terminal through the at least one transceiver, identifying a target satellite corresponding to a target terminal of the request message, determining whether it is possible to directly link to the target satellite, and when it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite through the at least one transceiver, and when it is not possible to directly link to the target satellite, identifying a second satellite that can form a direct link with the satellite, and sending the indication message to the second satellite through the at least one transceiver.

[0004] In an embodiment, a method performed by a satellite for providing access to a non-terrestrial network (NTN) is provided. The method performed by a satellite for providing access to a non-terrestrial network (NTN) may include the following steps: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether a direct link to the target satellite is possible, and when a direct link to the target satellite is possible, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, and when a direct link to the target satellite is not possible, identifying a second satellite that can form a direct link with the satellite, and sending the indication message to the second satellite.

[0005] In an embodiment, a non-transitory storage medium is provided. The non-transitory storage medium may include a memory, and the memory includes instructions. When the instructions are executed by a processor of a satellite, the satellite may perform the following operations: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether it is possible to directly link to the target satellite, and when it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, and when it is not possible to directly link to the target satellite, identifying a second satellite that can form a direct link with the satellite, and the second satellite sending the indication message. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A wireless communication system is shown.

[0007] Figure 2A and Figure 2B An example of NTN is shown.

[0008] Figure 3A An example of a control plane (C-plane) is shown.

[0009] Figure 3B An example of a user plane (U-plane) is shown.

[0010] Figure 4 An example of a resource structure in the time domain and frequency domain in a wireless communication system is shown.

[0011] Figure 5 An example of a network structure for NTN is shown.

[0012] Fig. 6A An example of a control plane for a regenerative satellite is shown.

[0013] Figure 6B An example of a user plane of a regenerative satellite is shown.

[0014] Fig. 7A A first example of an NTN scenario is shown.

[0015] Figure 7B An example of satellite (satellite as a non-terrestrial base station) switching is shown.

[0016] Figure 8 An example of a signal path utilizing an inter-satellite link (ISL) is shown.

[0017] Fig. 9An example of signaling using ISL is shown.

[0018] Fig.10 An example showing changes in a satellite due to orbital movement.

[0019] Fig.11 An example of path setting using ISL is shown.

[0020] Fig.12 An example of RRC configuration for path indication is shown.

[0021] Fig.13 Examples of components of a satellite are shown.

[0022] Fig.14 An example of components of a terminal is shown. DETAILED DESCRIPTION

[0023] The terms used in this disclosure are used only to illustrate specific embodiments and may not be intended to limit the scope of other embodiments. Unless the context clearly indicates a different meaning, a singular expression includes a plural expression. The terms used herein, including technical or scientific terms, may have the same meaning as that generally understood by a person of ordinary skill in the technical field recorded in this disclosure. Among the terms used in this disclosure, the terms defined in a general dictionary may be interpreted as having the same or similar meaning as that in the context of the associated technology, and unless clearly defined in this disclosure, should not be interpreted as an ideal or overly formal meaning. Depending on the circumstances, even the terms defined in this disclosure should not be interpreted as excluding the embodiments of the present disclosure.

[0024] In the various embodiments of the present disclosure described below, the hardware-based approach method is used as an example. However, since the various embodiments of the present disclosure include technologies that use both hardware and software, the various embodiments of the present disclosure do not exclude the software-based approach method.

[0025] The terms used in the following description to refer to signals (e.g., signal, information, message, signaling), terms to refer to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), occasion), terms used for operation states (e.g., step, operation, procedure), terms to refer to data (e.g., data packet, user flow, information, bit, symbol, codeword), terms to refer to channels, terms to refer to network entities, terms to refer to constituent elements of devices, etc. are exemplified for the convenience of explanation. Therefore, the present disclosure is not limited to the terms described later, but other terms with equivalent technical meanings may be used.

[0026] In the following description, physical channel and signal may be used interchangeably with data or control signal. For example, physical downlink shared channel (PDSCH) is a term referring to a physical channel for transmitting data, but PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "sending a physical channel" may be interpreted as being equivalent to the expression "sending data or a signal through a physical channel".

[0027] In the following disclosure, high-layer signaling refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of a physical layer, or in which a terminal transmits a signal to a base station using an uplink data channel of a physical layer. High-layer signaling can be understood as radio resource control (RRC) signaling or MAC control element (hereinafter referred to as "CE").

[0028] Furthermore, in the present disclosure, in order to determine whether a specific condition is met, the expression greater than or less than can be used, but this is only to express an example, and it is not intended to exclude the above or below record. The condition recorded as "above" can be replaced by "greater than", the condition recorded as "below" can be replaced by "less than", and the condition recorded as "above and less than" can be replaced by "greater than and below". Moreover, below, "A" to "B" represents at least one of the elements from A (including A) to B (including B). Hereinafter, "C" and / or "D" means including at least one of "C" and "D", that is, including "C", "D", "C" and "D".

[0029] In the present disclosure, signal quality may be, for example, at least one of reference signal received power (RSRP), beam reference signal received power (BRSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal to interference and noise ratio (SINR), carrier to interference and noise ratio (CINR), signal to noise ratio (SNR), error vector magnitude (EVM), bit error rate (BER) and block error rate (BLER). Of course, in addition to the above examples, other terms with equivalent technical meanings or other metrics representing channel quality may also be used. In the following, in the present disclosure, high signal quality means that the signal quality value related to the signal size is large or the signal quality value related to the error rate is small. Higher signal quality may mean that a smooth wireless communication environment is guaranteed. And, the best beam may refer to a beam having the highest signal quality among the beams.

[0030] The present disclosure uses terms used in some communication specifications (e.g., the 3rd Generation Partnership Project (3GPP) and the European Telecommunications Standards Institute (ETSI)) to describe various embodiments, but this is only an example for description. The various embodiments of the present disclosure can also be easily modified and applied in other communication systems.

[0031] Figure 1 A wireless communication system is shown.

[0032] Reference Figure 1 , Figure 1 A terminal 110 and a base station 120 are shown, which are a part of a node using a radio channel in a wireless communication system using New Radio (NR) as a wireless interface of a Radio Access Technology (RAT). Figure 1 Only one base station is shown, but the wireless communication system may also include other base stations that are the same or similar to base station 120 (e.g., NR gNB).

[0033] The terminal 110 is a device used by a user and communicates with the base station 120 through a wireless channel. The link from the base station 120 to the terminal 110 is called a downlink (DL), and the link from the terminal 110 to the base station 120 is called an uplink (UL). Figure 1 As shown, the terminal 110 and other terminals can communicate through wireless channels between each other. At this time, the link (device-to-device link, D2D) between the terminal 110 and the other terminal is called a sidelink, and the sidelink can be mixed with the PC5 interface. In some other embodiments, the terminal 110 can operate independently of the user. According to one embodiment, the terminal 110 is a device for performing machine type communication (machine type communication, MTC), which may not be carried by the user. And, according to one embodiment, the terminal 110 may be a narrowband Internet of Things (NB-IoT) device.

[0034] In this specification, when describing systems and methods, terminal 110 can be an electronic device for transmitting voice and / or data to base station 120, which can in turn communicate with a network of devices (e.g., a public switched telephone network (PSTN), the Internet, etc.).

[0035] Furthermore, in addition to being called a terminal, terminal 110 may also be called a “user equipment (UE)”, “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 other terms with equivalent technical meanings.

[0036] In addition, examples of the terminal 110 include a cellular phone, a smart phone, a personal digital assistant (PDA), a laptop computer, a netbook, an e-reader, and a wireless modem, etc. In the 3GPP standard, the terminal 110 is representatively referred to as a user equipment (UE). However, since the scope disclosed in this specification should not be limited to the 3GPP standard, the terms "UE" and "terminal" may be used interchangeably in this specification to refer to the more general term "wireless communication device". UE may also be more generally referred to as a terminal device.

[0037] The base station 120 is a network infrastructure that provides wireless access to the terminal 110. The base station 120 has a coverage range defined based on the distance at which a signal can be transmitted. In the 3GPP standard, in addition to "Node B", "evolved Node B (eNodeB, eNB)", "5G node (5th generationnode)", "next generation nodeB (next generationnodeB, gNB)", "home enhanced or evolved nodeB (HeNB)", the base station 120 is also generally referred to as "access point (access point, AP)", "wireless point (wireless point)", "transmission / reception point (transmission / reception point, TRP)" or other terms with equivalent technical meanings.

[0038] Since the scope of the contents disclosed in this specification should not be limited to the 3GPP standard, the terms "base station", "Node B", "eNB" and "HeNB" may be used interchangeably in this specification to refer to the more general term "base station". Also, the term "base station" may be used to refer to an access point. An access point may be an electronic device that provides wireless communication devices with access to a network (e.g., a local area network (LAN), the Internet, etc.). The term "communication device" may be used to refer to both a wireless communication device and / or a base station. An eNB or gNB may also be more generally referred to as a base station device.

[0039] The base station 120 may communicate with an NR core network (NR CN) entity 130. For example, the core network entity 130 may include an access and mobility management function (AMF) for a control plane such as access and mobility control functions of the terminal 110 and a user plane function (UPF) for a control function of user data.

[0040] The terminal 110 can perform beamforming with the base station 120. The terminal 110 and the base station 120 can send and receive wireless signals in a relatively low frequency band (for example, FR 1 (frequency range 1) of NR). In addition, the terminal 110 and the base station 120 can send and receive wireless signals in a relatively high frequency band (for example, FR 2 (or FR 2-1, FR 2-2, FR 2-3), FR 3) of NR, millimeter wave (mmWave) band (for example, 28GHz, 30GHz, 38GHz, 60GHz)). In order to improve the channel gain, the terminal 110 and the base station 120 can perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. The terminal 110 and the base station 120 can give directivity to the transmitted signal or the received signal. To this end, the terminal 110 and the base station 120 may select a serving beam through a beam search or beam management process. After selecting the serving beam, subsequent communications may be performed through resources having a quasi co-location (QCL) relationship with the resources transmitting the serving beam.

[0041] As long as the broad characteristics of the channel for transmitting symbols on the first antenna port can be inferred from the channel for transmitting symbols on the second antenna port, the first antenna port and the second antenna port can be evaluated as having a QCL relationship. For example, the broad characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameter.

[0042] Both the terminal 110 and the base station 120 may perform beamforming, but the embodiments of the present disclosure are not limited thereto. In some embodiments, the terminal 110 may perform or not perform beamforming. Also, the base station 120 may perform or not perform beamforming. That is, only one of the terminal 110 and the base station 120 may perform beamforming, or both the terminal 110 and the base station 120 may not perform beamforming.

[0043] In the present disclosure, a beam refers to the spatial flow of a signal in 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 may include at least one of analog beamforming or digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming may include, for example, a demodulation reference signal (DM-RS), a channel state information reference signal (CSI-RS), a synchronization signal / physical broadcast channel (SS / PBCH), and a sounding reference signal (SRS). Furthermore, as a configuration of each reference signal, information elements (IE) such as CSI-RS resources or SRS-resources may be used, and such a configuration may include information associated with the beam. The information associated with the beam may indicate whether the corresponding configuration (e.g., CSI-RS resource) and other configurations (e.g., other CSI-RS resources in the same CSI-RS resource set) use the same spatial domain filter (spatial domain filter) or different spatial domain filters, or which reference signal is quasi-co-located (QCL), and if so, which type of QCL (e.g., QCL type A, B, C, D).

[0044] Hereinafter, to illustrate the embodiment, the terminal may be referred to as UE 110 and the base station may be referred to as gNB 120.

[0045] Figure 2A and Figure 2B An example of NTN is shown. Figure 2A An example of NTN using transparent satellites is shown. Figure 2B An example of NTN using regenerative satellites is shown. NTN represents a NG-RAN that provides non-terrestrial NR access for UEs (e.g., UE 110) through NTN payloads and NTN gateways carried on airborne or space-borne NTN vehicles. The NG-RAN may include more than one gNB (e.g., gNB 120).

[0046] Reference Figure 2A , NTN 200 represents a network environment according to the transparent satellite. In NTN 200, as gNB120, NTN payload 221 and NTN gateway 223 may be included. NTN payload 221 is a network node carried on a satellite or high altitude platform station (HAPS) that provides a connection function between a service link (described later) and a feeder link (described later). NTN gateway 223 is an earth station (earth station) set on the surface of the earth that uses the feeder link to provide a connection to NTN payload 221. 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 NTN payload 221 and NTN gateway 223. The link between NTN payload 221 and UE 110 can be called a service link. The link between the NTN gateway 223 and the NTN payload 221 may be referred to as a feeder link. The feeder link may correspond to a wireless link.

[0047] The NTN payload 221 may receive radio protocol data from the UE 110 through a service link. The NTN payload 221 may transparently pass the radio protocol data to the NTN gateway 223 through a feeder link. Therefore, from the perspective of the UE 110, the NTN payload 221 and the NTN gateway 223 may be regarded as one gNB 120. The NTN payload 221 and the NTN gateway 223 may perform communication with the UE 110 through a Uu interface as a general radio protocol. That is, the NTN payload 221 and the NTN gateway 223 may perform radio protocol communication with the UE 110 like one gNB 120. The NTN gateway 223 may perform communication with the core network entity 235 (AMF or UPF) through an NG interface.

[0048] According to one embodiment, the NTN payload 221 and the NTN gateway 223 may utilize the following Figure 3A And, according to one embodiment, the NTN payload 221 and the NTN gateway 223 can utilize Figure 3B The wireless protocol stack in the user plane of the

[0049] exist Figure 2A1 and 2. The gNB 120 includes an NTN payload 221 and an NTN gateway 223, but the embodiments of the present disclosure are not limited thereto. For example, the gNB may include multiple NTN payloads. And, for example, the NTN payload may be provided by multiple gNBs. That is, Figure 2A The implementation scenario shown is an example and does not limit the embodiments of the present disclosure.

[0050] Reference Figure 2B , NTN 250 represents a network environment according to the regenerative satellite. NTN 250 may include a satellite 260 acting as a gNB120. Satellite 260 represents a space-borne vehicle carrying a regenerative payload communication transmitter set in low-earth orbit (LEO), medium-earth orbit (MEO) or geostationary earth orbit (GEO). Satellite 260 may be referred to as a regenerative payload or a regenerative satellite. Satellite 260 represents a payload configured to convert and amplify an uplink RF signal before sending it to a downlink, and the conversion of the signal may refer to digital processing that may include demodulation, decoding, recoding, remodulation and / or filtering. NTN 250 may include an entity connected to satellite 260 and deployed on the ground, namely NTN gateway 265. NTN gateway 265 is an earth station (earth station) deployed on the surface of the earth and providing a connection to satellite 260 using the feeder link. NTN 250 may provide non-terrestrial NR access to UE 110. NTN 250 may provide non-terrestrial NR access to UE 110 via satellite 260 and NTN gateway 265.

[0051] Satellite 260 may be configured to reproduce signals received from the earth. A Uu interface may be defined between satellite 260 and terminal 110. A satellite radio interface (SRI) on a feeder link may be defined between satellite 260 and NTN gateway 265. Figure 2B2. As not shown in the figure, the satellite 260 may provide an inter-satellite link (ISL) between satellites. The ISL is a transmission link between satellites. The ISL may be a transmission link between satellites, and the ISL may be a wireless interface (e.g., XN interface) defined in 3GPP or an optical interface not defined in 3GPP. The satellite 260 may communicate with the core network entity 235 (AMF or UPF) through the NG interface based on the NTN gateway 265. According to an embodiment, the satellite 260 may utilize the NG interface described later. Figure 3A And, according to one embodiment, the satellite 260 can utilize the wireless protocol stack in the control plane. Figure 3B The wireless protocol stack in the user plane.

[0052] although Figure 2B , the satellite 260 acting as the gNB 120 is described, but the embodiments of the present disclosure are not limited thereto. The gNB 120 according to the embodiment can be implemented as a distributed deployment (distributed deployment) using a centralized unit (CU) configured to perform the functions of the upper layers (upper layers) of the access network (e.g., packet data convergence protocol (PDCP), RRC) and a distributed unit (DU) configured to perform the functions of the lower layers. The interface between the CU and the DU can be referred to as an F1 interface. The CU is connected to more than one DU and can be responsible for functions of a higher layer than the DU. For example, the CU is responsible for the functions of the RRC and PDCP layers, and the DU and the radio unit (RU) can be responsible for the functions of the lower layers. The DU can be responsible for the functions of the radio link control (RLC), the media access control (MAC), and the physical (PHY) layers. In this distributed deployment, the satellite 260 can be used as a CU or DU constituting the gNB 120.

[0053] Figure 3A An example of a control plane (C-plane) is shown. In the following, at least some of the descriptions of gNB 120 may be understood as descriptions about satellite 260.

[0054] Reference Figure 3AIn the control plane, UE 110 and AMF 235 may perform non-access stratum (NAS) signaling. In the control plane, UE 110 and gNB 120 may perform communications corresponding to the specified protocol in the RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer, respectively.

[0055] In NTN access, the main functions of the RRC layer may include at least part of the following functions:

[0056] -Access Stratum (AS) and NAS related system information broadcast;

[0057] - Paging initiated by the 5G Core (5GC) or the Next Generation-Radio Access network (NG-RAN);

[0058] - Establishment, maintenance and release of the RRC connection between the UE and NG-RAN, including the following, more specifically, control of RLC, MAC and PHY:

[0059] -Addition, modification and release of carrier aggregation,

[0060] -Addition, modification and release of dual connectivity between NR or E-UTRA and NR;

[0061] -Including security functions of key management;

[0062] - Establishment, configuration, maintenance management and release of signaling radio bearers (SRB) and data radio bearers (DRB)

[0063] - Mobile features include:

[0064] - Handover and context transfer,

[0065] -UE cell selection and reselection and cell selection and reselection control,

[0066] - Inter-RAT mobility;

[0067] -Quality of service (QoS) management function;

[0068] -UE measurement reporting and control of reporting;

[0069] -Radio link failure sensing and recovery;

[0070] -Transfer of information from UE to NAS / transfer of information from NAS to UE.

[0071] In NTN access, the main functions of the PDCP layer may include at least part of the following functions:

[0072] -Header compression and decompression (ROHC only)

[0073] -Transfer of user data

[0074] -In-sequence delivery of upper layer PDUs

[0075] -Out-of-sequence delivery of upper layer PDUs

[0076] -PDCP PDU reordering for reception

[0077] -Duplicate detection of lower layer SDUs

[0078] -Retransmission of PDCP SDUs

[0079] -Ciphering and deciphering

[0080] -Timer-based SDU discard in uplink.

[0081] In NTN access, the main functions of the RLC layer may include at least part of the following functions:

[0082] -Transfer of upper layer PDUs

[0083] -In-sequence delivery of upper layer PDUs

[0084] -Out-of-sequence delivery of upper layer PDUs

[0085] -Error Correction through ARQ

[0086] -Concatenation, segmentation and reassembly of RLC SDUs

[0087] -Re-segmentation of RLC data PDUs

[0088] -Reordering of RLC data PDUs

[0089] -Duplicate detection

[0090] -Protocol error detection

[0091] -RLC SDU discard

[0092] -RLC re-establishment.

[0093] In NTN access, the MAC layer can be connected to multiple RLC layer devices configured in a terminal. The main functions of MAC may include at least part of the following functions:

[0094] -Mapping between logical channels and transport channels

[0095] -Multiplexing / demultiplexing of MAC SDUs

[0096] -Scheduling information reporting

[0097] -Error correction through HARQ

[0098] -Priority handling between logical channels of one UE

[0099] -Priority handling between UEs by means of dynamic scheduling

[0100] -MBMS service identification

[0101] -Transport format selection

[0102] -Padding.

[0103] In NTN access, the physical layer may perform channel coding and modulation on high-layer data, make it into OFDM symbols and transmit it through a wireless channel, or demodulate and channel decode the OFDM symbols received through a wireless channel and transmit them to a high-layer.

[0104] Figure 3B An example of a user plane is shown. In the following, at least some of the descriptions of gNB 120 may be understood as descriptions of satellite 260.

[0105] Reference Figure 3B In the user plane, UE 110 and gNB 120 may perform communications corresponding to the specified protocols 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 other than the SDAP layer, reference may be made to Figure 3A Description.

[0106] In NTN access, the SDAP layer can provide 5GC QoS flows. A single protocol entity of SDAP can be configured for each PDU session. The functions of the SDAP layer may include at least part of the following functions:

[0107] -Mapping between QoS flows and data radio bearers;

[0108] - Indicates the QoS Flow Identifier (QFI) in both DL and UL packets.

[0109] Figure 4 An example of a resource structure in the time domain and the frequency domain supported by a wireless communication system to which the embodiments proposed in this specification can be applied is shown. Figure 4 The basic structure of the time domain-frequency domain is shown, which is a wireless resource area for transmitting data channels or control channels in the downlink or uplink in the 5G NR system to which this embodiment can be applied.

[0110] Reference Figure 4 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain is the OFDM symbol, which consists of N symb OFDM symbols 402 are aggregated to form a time slot 406. Figure 4 In the wireless communication system to which the present invention is applied, a radio frame 414 can be defined as consisting of 10 subframes of the same length of 1 ms, and thus has a length of 10 ms. In addition, a radio frame 414 can be divided into half-frames of 5 ms, and each half-frame includes 5 subframes. Figure 4 In the case of a 15 kHz subcarrier spacing, the time slot 406 consists of 14 OFDM symbols, but the length of the time slot can vary depending on the subcarrier spacing. For example, in the case of a 15 kHz subcarrier spacing, the time slot length is 1 ms and has the same length as the subframe. Differently, in the case of a 30 kHz subcarrier spacing, the time slot consists of 14 OFDM symbols, but a subframe can include two time slots of length 0.5 ms.

[0111] That is, a subframe and a frame are defined to have a fixed time length, and a time slot is defined by the number of symbols, so the time length may vary according to the subcarrier spacing. Figure 4 The radio resources supported by the wireless communication system to which the invention proposed in this specification can be applied are composed of symbols as multiple time resources and sub-carriers as multiple frequency resources, and each time resource and frequency resource can be represented as a two-dimensional resource grid. Figure 4 In the resource grid, a square of the smallest physical resource consisting of one subcarrier and one symbol is called a resource element (RE) 412.

[0112] In a 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 constituting the resource grid is N. BW The number of subcarriers is 404.

[0113] In the time-frequency domain, the basic unit of resources is a resource element (hereinafter referred to as "RE") 412, which can be represented by an OFDM symbol index and a subcarrier index. A resource block 408 may include multiple resource elements 412. In a 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")) may be defined as N in the time domain. symb consecutive OFDM symbols and N in the frequency domain SC RB In the NR system, resource block 408 can be defined as N consecutive subcarriers in the frequency domain. SC RB subcarriers 410. A resource block 408 includes N subcarriers 410 on the frequency axis. SC RB resource elements 412.

[0114] Generally speaking, the minimum data transmission unit is RB, and the number of subcarriers N SC RB The frequency domain may include common resource blocks (CRBs). Physical resource blocks (PRBs) may be defined in a portion of the bandwidth on the frequency domain. CRBs and PRB numbers may be determined based on subcarrier spacing. The data rate may be increased in proportion to the number of RBs scheduled to the terminal.

[0115] In the NR system, in the case of a frequency division duplex (FDD) system in which the downlink and uplink are divided and operated by frequency, the downlink transmission bandwidth and the uplink transmission bandwidth may be different from each other. The channel bandwidth represents the radio frequency (RF) bandwidth corresponding to the system transmission bandwidth. Table 1 shows a part of the correspondence between the system transmission bandwidth, subcarrier spacing, and channel bandwidth defined in the NR system in a frequency band (e.g., FR 1 (410 MHz to 7125 MHz)) lower than the upper limit defined in the standard (e.g., 7.125 GHz). In addition, 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 (e.g., FR2 (24250 MHz to 52600 MHz) or FR2-2 (52600 MHz to 71000 MHz)) higher than the lower limit defined in the standard (e.g., 24.25 GHz). For example, in an NR system with a 100 MHz channel bandwidth with a 30 kHz subcarrier spacing, the transmission bandwidth consists of 273 RBs. In Tables 1 and 2, N / A may be a bandwidth-subcarrier combination that is not supported in the NR system.

[0116] [Table 1]

[0117]

[0118] [Table 2]

[0119]

[0120]

[0121] Figure 5 An example of a network structure for NTN is shown. Satellite 260 may be carried on a space vehicle or aerial vehicle to provide structure, power, command, telemetry, attitude control of the satellite (corresponding HAPS), and appropriate thermal environment and radiation shielding. Figure 5 , satellite 260 is described as a regenerative payload as an example of the actions of a full base station (e.g., gNB 120).

[0122] Reference Figure 5 , the satellite 260 can act as a gNB 120. The gNB 120 can communicate with the terminal 110 or with the core network entity 130. Figure 5500 is shown as the core network entity 130. An NR Uu interface 502 may be utilized between the satellite 260 and the terminal 110. According to an embodiment, at least one radio bearer 520 may be generated between the satellite 260 and the terminal 110. For example, the radio bearer 520 may include a data radio bearer (DRB). For example, the radio bearer 520 may include a signaling radio bearer (SRB). An NG interface 504 may be utilized between the satellite 260 and the core network entity (e.g., AMF, UPF). For example, an N3 interface may be utilized between the satellite 260 and the UPF. For example, an N2 interface may be utilized between the satellite 260 and the AMF. According to an embodiment, a traffic tunnel may be generated between the satellite 260 and the core network entity 130. For example, a next generation user plane (NG-U) tunnel 530 may be generated between the satellite 260 and the UPF 550.

[0123] A packet data unit (PDU) session 540 may be generated between the UE 110 and the core network entity 130 (e.g., UPF 550). The PDU session 540 may be used to provide an end-to-end user plane connection between the terminal 110 and the data network through the UPF 550. The PDU session 540 may support more than one quality of service (QoS) flow. For example, the PDU session 540 may support a first QoS flow 511 and a second QoS flow 512. In the user plane, the radio bearer 520 may be mapped to the QoS flow (e.g., the first QoS flow 511, the second QoS flow 512). According to an embodiment, the satellite 260 is a gNB 120 and may perform mapping between DRBs and QoS flows.

[0124] although Figure 5 Although not shown, operations and maintenance (O&M) may be used to provide a wireless access network via satellite 260. O&M may provide one or more parameters associated with NTN 500 to gNB 120 (e.g., satellite 260). For example, O&M 510 may provide the following NTN-related parameters to gNB 120 at a minimum for operation:

[0125] a) Earth fixed beams: For each beam provided by a given NTN payload:

[0126] - the cell identifiers (NG and Uu) mapped to the beams,

[0127] - The reference location of the cell (e.g. the center and the area of ​​the cell);

[0128] b) Quasi Earth Fixed Beams: For each beam provided by a given NTN payload:

[0129] - the cell identifier (NG and Uu) and time window mapped to the beam,

[0130] - the reference location of the cell / beam (e.g. the center and range of the cell),

[0131] - time window for successive switch-overs (feeder links, service links),

[0132] - Identifiers and time windows of all satellites and NTN gateways providing services;

[0133] c) Earth moving beams: For each beam provided by a given NTN payload:

[0134] - Uu cell identifiers mapped to beams and mapping information related to fixed geographical areas reported to the NG, information related to the movement of the footprint of the beam in the earth,

[0135] - elevation relative to the NTN payload,

[0136] -Continuous service scheduling of NTN-gateway / gNB,

[0137] - Continuous switch-over scheduling (feeder link, service link).

[0138] Fig. 6A An example of a control plane for a regenerative satellite (eg, satellite 260 ) is shown.

[0139] Reference Fig. 6A UE 610 can support protocols of PHY layer, MAC layer, RLC layer, PDCP layer and RRC layer. Satellite 620 as gNB can support protocols of PHY layer, MAC layer, RLC layer, PDCP layer and RRC layer. For satellite 620, refer to the description of satellite 260. For the description of each layer protocol, refer to Figure 3A The interface between the UE 610 and the satellite 620 may be a Uu interface.

[0140] Satellite 620 is a gNB or part of a gNB mounted on a board, and can perform NG-RAN protocol functions. Satellite 620 can communicate (e.g., IP communication) with NTN gateway 630 located on the ground through SRI. Satellite 620 can access 5GC through NTN gateway 630. As a network entity for the 5GC, AMF 640 (e.g., AMF 235 and SMF650) is illustrated. Satellite 620 can support NG-AP layer, stream control transmission protocol (SCTP) layer, and IP layer protocols to communicate with 5GC. The NG-AP layer can be used between AMF640 as a 5GC entity and satellite 620 through NTN gateway on SCTP. NAS signaling between UE 610 and AMF 640 can be performed through satellite 620 and NTN gateway 630. The NAS signaling may include a NAS-mobility management (MM) interface for AMF 640. The NAS signaling may include NAS-SM relay and / or NAS-session management (SM) for SMF 650. The NAS signaling may be transmitted between AMF 640 as a 5GC entity and satellite 620 through NTN gateway 630 through NG-AP layer protocol.

[0141] exist Fig. 6A In the example of the satellite acting as a complete gNB, the embodiments of the present disclosure are described, but the embodiments of the present disclosure are not limited thereto. As a non-limiting example, the satellite may act as a gNB-DU with functional separation. Thus, the satellite may also be configured to support protocols of the RLC layer, the MAC layer, and the PHY layer.

[0142] Figure 6B An example of a user plane of a regenerative satellite (eg, satellite 260) is shown.

[0143] Reference Figure 6B UE 610 can support protocols of PHY layer, MAC layer, RLC layer, PDCP layer and SDAP layer. Satellite 620 as gNB can support protocols of PHY layer, MAC layer, RLC layer, PDCP layer and SDAP layer. The description of each layer protocol can refer to Figure 3B The interface between the UE 610 and the satellite 620 may be a Uu interface.

[0144] The satellite 620, as a gNB mounted on board, can perform NG-RAN protocol functions. The satellite 620 can communicate with the NTN gateway 630 located on the ground through SRI (e.g., IP communication). The satellite 620 can access the 5GC through the NTN gateway 630. As a network entity for the 5GC, the UPF 680 is illustrated. The satellite 620 can support the protocols of the general packet radio service tunneling protocol-user plane (GPRS (General Packet Radio Service) tunneling protocol-user plane, GTP-U) layer, the user datagram protocol (user datagram protocol, UDP) layer, and the IP layer to communicate with the 5GC. A PDU session (e.g., Figure 5 The SRI protocol stack can be used to transmit the UE user plane between the satellite and the NTN-gateway. The signal on the PDU session can be transmitted between the UPF 680 as 5GC and the satellite 620 through the NTN gateway 630 through the GTP-U tunnel.

[0145] exist Figure 6B In the example in which the satellite acts as a complete gNB, the embodiments of the present disclosure are not limited thereto. As a non-limiting example, the satellite may act as a gNB-DU with functional separation. Thus, the satellite may also be configured to support protocols of the RLC layer, the MAC layer, and the PHY layer.

[0146] Fig. 7A A first example of an NTN scenario is shown. Fig. 7A A typical scenario of NTN based on transparent payload is shown in FIG.

[0147] Reference Fig. 7A , a satellite (or an unmanned aerial system (UAS) platform) may generate a service link with a UE. A satellite (or a UAS platform) may be connected to a gateway via a feeder link. A satellite may be connected to a data network via a gateway. A beam footprint may refer to an area in which a signal transmitted by a satellite can be received.

[0148] The following figures are prepared to illustrate specific examples of this specification. Since the names of specific devices or specific signals / messages / fields recorded in the figures are provided as examples, the technical features of this specification are not limited to the specific names used in the following figures.

[0149] Figure 7BAn example of switching of a satellite (a satellite that is not a terrestrial base station) is shown. Figure 7B A typical scenario of NTN based on regenerative payload is shown in FIG.

[0150] Reference Figure 7B , a satellite (or UAS platform) can generate a service link with the UE. A satellite (or UAS platform) connected to a UE can be connected to another satellite (or UAS platform) via an inter-satellite link (ISL). Another satellite (or UAS platform) can be connected to a gateway via a feeder link. A satellite can be connected to a data network through another satellite and a gateway based on a regenerated payload. When there is no ISL between a satellite and another satellite, a feeder link between the satellite and the gateway is required.

[0151] For reference, the above Fig. 7A and Figure 7B The scenarios in FIG. 1 are merely examples of NTN scenarios, and NTN can be implemented based on scenarios in various ways.

[0152] NTN can generally be characterized by the following elements:

[0153] -One or more satellite gateways (sat-gateway) connecting the NTN to the public data network:

[0154] i) Geostationary satellites may be fed by one or more satellite gateways deployed in the satellite object area (e.g., regional or even continental coverage). It can be assumed that UEs in a cell receive services only through one satellite gateway.

[0155] ii) Non-GEO satellites can be served continuously by one or more satellite gateways at a time. The system has a duration sufficient for mobility anchoring and handover, ensuring service and feeder link continuity between consecutive serving satellite gateways.

[0156] -Feeder link or wireless link between satellite gateway and satellite (or UAS platform).

[0157] - A service link or wireless link between the UE and the satellite (or UAS platform).

[0158] -Satellites (or UAS platforms) capable of transparent or regenerative (with on board processing) payloads. Satellites (or UAS platforms) can typically generate multiple beams over a specified service area based on the satellite's (or UAS platform's) field of view. The coverage area of ​​the beams can typically be elliptical. The satellite's (or UAS platform's) field of view may vary based on the onboard antenna diagram and minimum elevation angle:

[0159] i) Transparent payload: may include RF filtering, frequency conversion and amplification. Therefore, the waveform signal repeated through the payload may not be changed.

[0160] ii) Regenerative payload: may include RF filtering, frequency conversion and amplification, demodulation / decoding, switching and / or routing, and coding / modulation. The regenerative payload may be substantially the same as all or part of the base station functionality (e.g., gNB) onboard the satellite (or UAS platform).

[0161] - In the case of a constellation of satellites, an inter-satellite link (ISL) may be optionally included. For this purpose, the satellite may require a regenerative payload. The ISL may operate at RF frequencies or broadband.

[0162] - The UE can be served by a satellite (or UAS platform) within the target service area.

[0163] Table 3 below shows a list of various types of satellites (or UAS platforms).

[0164] [Table 3]

[0165]

[0166]

[0167] Figure 8 An example of a signal path using an inter-satellite link is shown. An embodiment of the present disclosure proposes an apparatus and method for providing a signaling connection between two terminals via a satellite. In the present disclosure, a satellite may be a regenerative satellite or a transparent satellite. Each satellite exemplifies a satellite 260 or a satellite 620.

[0168] Reference Figure 8, the first UE 811 may be in a state of being connected to the first satellite 801. For example, the first satellite 801 may provide a first cell. The first UE 811 may be in a state of being connected on the first cell. The user of the first UE 811 may wish to communicate with the user of the fifth UE 815. The fifth UE 815 may be in a state of being connected to the fifth satellite 805. For example, the fifth satellite 805 may provide a second cell. The fifth UE 815 may be in a state of being connected on the second cell. The first UE 811 may be located within the coverage area of ​​the first satellite 801, i.e., the first coverage area 821. The fifth UE 815 may be located within the coverage area of ​​the fifth satellite 805, i.e., the fifth coverage area 825. Since the location of the user of the first UE 811 is geographically significantly far away from the location of the user of the fifth UE 815, a signal path using ISL may be used.

[0169] The first satellite 801 may be connected to the second satellite 802. The second satellite 802 may be connected to the third satellite 803. The third satellite 803 may be connected to the fourth satellite 804. The fourth satellite 804 may be connected to the fifth satellite 805. A signal path may 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 (hereinafter referred to as a satellite link or a satellite relay link) between the first satellite 801 and the fifth satellite 805 may be generated by relaying 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 plurality of UEs (the first UE 811 and the fifth UE 815) located in completely different locations (e.g., the first coverage area 821 and the fifth coverage area 825) may create a satellite link through a process according to an embodiment of the present disclosure.

[0170] When entering the first cell of the first satellite 801, the first UE 811 may register the location of the first UE 811 in a Home Location Register (HLR) or an AMF (e.g., AMF 640) of the NTN network. When entering the second cell of the fifth satellite 805, the fifth UE 815 may register the fifth UE 815 in the HLR or AMF (e.g., AMF 640) of the NTN network. The location of the first UE 811 may be managed by the first satellite 801 or a core network entity connected to the first satellite 801 through a TAU process or an exchange process between upper node entities. The location of the fifth UE 815 may be managed by the fifth satellite 805 or a core network entity connected to the fifth satellite 805 through a TAU process or a process between upper node entities.

[0171] According to an embodiment, in order to specify the area where the first UE 811 is located, the identification information of the first coverage area 821 (e.g., coverage area ID#1), the identification information of the first satellite 801 (e.g., satellite ID#1), and the beam identification information (e.g., spot beam ID#1) of the first satellite 801 may be used. In order to specify the area where the fifth UE 815 is located, the identification information of the fifth coverage area 825 (e.g., coverage area ID#5), the identification information of the fifth satellite 805 (e.g., satellite ID#5), and the beam identification information (e.g., spot beam ID#5) of the fifth satellite 805 may be used.

[0172] According to an embodiment, a plurality of satellites (e.g., a second satellite 802, a third satellite 803, and a fourth satellite 804) capable of forming a satellite link between a first satellite 801 and a fifth satellite 805 may be used. For example, a first adjacent satellite adjacent to the first satellite 801 may be identified. A second satellite 802 may be identified in the first adjacent satellite. A second adjacent satellite adjacent to the second satellite 802 may be identified. A third satellite 803 may be identified in the second adjacent satellite. A third adjacent satellite adjacent to the third satellite 803 may be identified. A fourth satellite 804 may be identified in the third adjacent satellite. A fourth adjacent satellite adjacent to the fourth satellite 804 may be identified. A fifth satellite 805 may be identified in the fourth adjacent satellite. The plurality of satellites forming a satellite link between the first satellite 801 and the fifth satellite 805 may be determined by various entities. For example, the plurality of satellites may be determined by a master satellite in a satellite group. The master satellite may set a path between satellites. For example, the plurality of satellites may be determined by an AMF (e.g., AMF 640). The AMF may identify a plurality of satellites for forming a satellite link through a path selection algorithm among a plurality of satellites associated with the first satellite 801 and the fifth satellite 805. For example, each of the plurality of satellites may be determined by a separate satellite forming a path. The second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805 may be identified by the first satellite 801, the second satellite 802, the third satellite 803, and the fourth satellite 804, respectively.

[0173] The first UE 811 may request a call connection with the fifth UE 815 on the first cell of the first satellite 801. The first UE 811 is a calling party device, and the fifth UE 815 may correspond to a called party device. The first UE 811 may send a request message for a call connection to the first satellite 801. The first satellite 801 may determine whether a direct link from the first satellite 801 to the fifth satellite 805 can be set in response to the request message. The first satellite 801 may be referred to as a source satellite. The fifth satellite 805 may be referred to as a target satellite. A direct link refers to a link in which a source satellite (e.g., the first satellite 801) and a target satellite (e.g., the fifth satellite 805) are directly connected without the intervention of another satellite (i.e., without the relay of another satellite).

[0174] For example, a direct link from the first satellite 801 to the fifth satellite 805 can be set. 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. When the fifth satellite 805 is included in the list, the first satellite 801 can determine that a direct link from the first satellite 801 to the fifth satellite 805 can be set. The first satellite 801 can send a link setup request message to the fifth satellite 805. The fifth satellite 805 can send a link setup response message to the first satellite 801. A link between the first satellite 801 and the fifth satellite 805 can be established.

[0175] 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 may be identified. The first satellite 80 may determine whether the fifth satellite 805 is included in the list. When the fifth satellite 805 is not included in the list, the first satellite 801 may determine that a direct link from the first satellite 801 to the fifth satellite 805 cannot be set up. The first satellite 801 may identify the second satellite 802 among the satellites included in the list. The first satellite 801 may send a link setup request message to the second satellite 802. The second satellite 802 may send a link setup response message to the first satellite 801. A link between the first satellite 801 and the second satellite 802 may be established. The first satellite 801 may send an indication message for a call connection between the first UE 811 and the fifth UE 815 to the second satellite 802 through the above link. By repeating this process, a link between the second satellite 802 and the third satellite 803 may be established. The second satellite 802 may send an indication message for a call connection between the first UE 811 and the fifth UE 815 to the third satellite 803 through the above link. By repeating the process, a link between the third satellite 803 and the fourth satellite 804 may be established. The third satellite 803 may send an indication message for a call connection between the first UE 811 and the fifth UE 815 to the fourth satellite 804 through the above link. By repeating the process, a link between the fourth satellite 804 and the fifth satellite 805 may be established. The fourth satellite 804 may send an indication message for a call connection between the first UE 811 and the fifth UE 815 to the fifth satellite 805 through the above link. Through the established link, a satellite link from the first satellite 801 to the fifth satellite 805 may be formed.

[0176] After forming a satellite link with the first satellite 801, the fifth satellite 805 may transmit a signal to the fifth UE 815 within the fifth coverage area 825. The signal may be a paging signal, a wake-up signal, or an incoming request signal. The fifth UE 815 may perform a call setup procedure with the fifth satellite 805 in response to the signal. When the call setup procedure between the fifth UE 815 and the fifth satellite 805 is completed, the first UE 811 may communicate with the fifth UE 815.

[0177] Fig. 9 An example of signaling using ISL is shown. Fig. 9815. A case where it is difficult to set up a direct link between the first UE 811 and the fifth UE 815 is described in FIG. 816. A link between the first UE 811 and the second UE 812 is established, and an indication message for a call connection can be transmitted over the link. As an example, if all satellites are regenerative satellites, the interface between the satellites can be an XN interface. The indication message can be transmitted over the XN interface.

[0178] Reference Fig. 9 In action 901, the first satellite 801 may send an indication message to the second satellite 802. For example, the indication message may be configured for a call connection between the first UE 811 and the fifth UE 815.

[0179] although Fig. 9 Although not shown in the figure, the first satellite 801 may receive a request message for a call connection from the first UE 811. The request message includes identification information of the first UE 811 corresponding to the calling party (e.g., UE ID, global unite temporary identifier (GUTI), International Mobile Subscriber Identity (IMSI)), identification information of the fifth UE 815 corresponding to the called party (e.g., UE ID, GUTI, IMSI), identification information of a serving cell of the first UE 811, and / or identification information related to the first satellite 801 providing a serving cell for the first UE 811.

[0180] In response to the request message, the first satellite 801 may identify the target satellite. The first satellite 801 may 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 may identify the fifth satellite 805 that provides the service cell of the fifth UE 815 based on the information related to the area. The first satellite 801 may identify the fifth satellite 805 as the target satellite. According to an embodiment, the first satellite 801 may generate an indication message including information related to the target satellite (e.g., identification information related to the fifth satellite 805). The subject of identifying the target satellite may be performed by a separate network entity (e.g., AMF or HLR server) connected to the first satellite 801 or a main satellite in the satellite group instead of being performed by the first satellite 801. According to one embodiment, the indication message may include identification information of the first UE 811, identification information of the fifth UE 815, identification information of the first satellite 801 as a source satellite, identification information of the fifth satellite 805 as a target satellite, information related to the first cell provided by the first satellite 801 (for example: physical cell identity (PCI), cell global identity (CGI)), and / or information related to the second cell provided by the fifth satellite 805 (for example: PCI, CGI).

[0181] After identifying the target satellite, the first satellite 801 may determine a path from the first satellite 801 as a source satellite to the fifth satellite 805 as a target satellite. The path may include multiple satellites. According to an embodiment, the first satellite 801 may generate an indication message including information related to the satellites on the path. The main body of determining the path may be performed by a separate network entity (e.g., AMF or HLR server) connected to the first satellite 801 or a master satellite in a satellite group instead of the first satellite 801. If the path is set by an external network entity, the first satellite 801 may generate an indication message including information related to the satellites on the set path. However, the satellite not only moves continuously along the orbit, but also the orbits are not parallel to each other, so the best link in the three-dimensional space may change over time. Therefore, when a request message for a call connection is first received, a scheme of providing constellation information and / or ephemeris information for establishing a link to an adjacent satellite may be considered instead of setting the entire satellite path. For example, the ephemeris information may include position-velocity information and orbit information. The position-velocity information respectively represents a position vector and a velocity vector in an XYZ coordinate system, and the orbit information represents a major semi-axis, an eccentricity, a perihelion, a longitude and / or an inclination.

[0182] According to an embodiment, the first satellite 801 may generate an indication message including direction information. The first satellite 801 may obtain constellation information and / or ephemeris information of the fifth satellite 805. The first satellite 801 may determine the direction information based on the ephemeris information of the first satellite 801 and the ephemeris information of the fifth satellite 805. For example, the first satellite 801 may 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 moment. According to the direction, satellites on the satellite path (e.g., the second satellite 802, the third satellite 803, and the fourth satellite 804) may be identified. For example, the direction may be obtained by the difference between the position vector of the first satellite 801 as the source satellite and the position vector of the fifth satellite 805 as the target satellite in the XYZ coordinate system. The direction may correspond to a direction vector expressed on the XYZ coordinate system.

[0183] The first satellite 801 may send the generated indication message to the adjacent second satellite 802. For example, the second satellite 802 may be indicated by an external network entity (AMF, HLR server, or a main satellite in the satellite group). For another example, the second satellite 802 may be a satellite corresponding to a specific direction (e.g., a direction from the first satellite 801 to the fifth satellite 805) among the adjacent satellites adjacent to the first satellite 801.

[0184] Fig. 9 , an indication message between the first satellite 801 and the second satellite 802 is shown, but the embodiments of the present disclosure are not limited thereto. As long as it is an ISL, it can be applied to the transmission of the above indication message. For example, the description of the indication message can also be applied to the indication message between the second satellite 802 and the third satellite 803. For example, the description of the indication message can also be applied to the indication message between the third satellite 803 and the fourth satellite 804. For example, the description of the indication message can also be applied to the indication 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. As the number of satellites on the satellite link increases, it may be difficult to ensure stable communication performance. Therefore, the first satellite 801 can generate an indication message including the number of hops of the satellite link. Whenever the indication message passes through each link of the satellite path, the number of hops can be reduced. For example, if the number of hops in the indication message from the first satellite 801 is 5, the number of hops in the indication messages sent to the second satellite 802 and the third satellite 803 may be 4.

[0185] According to an embodiment, the indication message may include at least one of the items listed in the following table: The indication message may be transmitted via an inter-satellite link (eg, ISL), that is, transmitted from a specific satellite to another satellite.

[0186] [Table 4]

[0187]

[0188]

[0189] Fig.10 An example showing changes in a satellite due to orbital movement.

[0190] Reference Fig.10 , the first satellite 801 may move along the designated orbit 1007. For example, the first satellite 801 may move along the designated orbit 1007 in a clockwise direction. Currently, the first satellite 801 provides services to the first coverage area 821 through the first beam 1077. However, when a certain period of time has passed, it may be difficult for the first satellite 801 to provide services to the first coverage area 821. Another satellite (for example, the sixth satellite 1001) may provide services to the first coverage area 821. Therefore, the first satellite 801 not only provides the second satellite 802 with information related to the first satellite 801, but also provides information related to the satellite after the first satellite 801 (hereinafter referred to as the successor satellite) (for example, the sixth satellite 1001). According to an embodiment, the indication message may include information related to the successor satellite of the first satellite 801.

[0191] although Fig.10 Although not shown in the figure, the target satellite may also move along a specified orbit like the source satellite. Therefore, after a certain period of time, the fifth satellite 805 may no longer provide services to the fifth coverage area 825. After the certain period of time, another satellite after the fifth satellite 805 may provide services to the fifth coverage area 825.

[0192] Each satellite can know the ephemeris information of another satellite. Therefore, the satellite can know at which location another satellite provides service at a specific time. For example, the first satellite 801 can identify the satellite after 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 after the first satellite 801. The indication message may include information related to the at least one first satellite, the beam ID information of each satellite in the at least one first satellite, the time each satellite in the at least one first satellite stays in the corresponding coverage area, and the cell information of each satellite in the at least one first satellite (for example: in the case of a transparent payload, the cell is maintained by switching (switch-over), but in the case of a regenerative payload, the cell is changed). The first satellite 801 can identify at least one second satellite after the second satellite 802. The indication message may include information related to the at least one second satellite, beam ID information of each of the at least one second satellite, the time each of the at least one second satellite stays in the corresponding coverage area, and cell information of each of the at least one second satellite (e.g., in the case of a transparent payload, the cell is maintained by switching, but in the case of a regenerative payload, the cell is changed). The first satellite 801 may identify at least one third satellite after the third satellite 803. The indication message may include information related to the at least one third satellite, beam ID information of each of the at least one third satellite, the time each of the at least one third satellite stays in the corresponding coverage area, and cell information of each of the at least one third satellite (e.g., in the case of a transparent payload, the cell is maintained by switching, but in the case of a regenerative payload, the cell is changed). The first satellite 801 may identify at least one fourth satellite after the fourth satellite 804. The indication message may include information related to the at least one fourth satellite, beam ID information of each of the at least one fourth satellite, the time each of the at least one fourth satellite stays in the corresponding coverage area, and cell information of each of the at least one fourth satellite (e.g., in the case of a transparent payload, the cell is maintained by switching, but in the case of a regenerative payload, the cell is changed). The first satellite 801 may identify at least one fifth satellite after the fifth satellite 805.The indication message may include information related to the at least one fifth satellite, beam ID information of each of the at least one fifth satellite, time for each of the at least one fifth satellite to stay in a corresponding coverage area, and cell information of each of the at least one fifth satellite (e.g., maintaining the cell by switching in the case of a transparent payload, but changing the cell in the case of a regenerative payload). The subject of identifying the successor satellite may be performed by a separate network entity (e.g., AMF or HLR server) connected to the first satellite 801 or a master satellite within the satellite group instead of the first satellite 801.

[0193] Fig.10 It is described in that, according to the orbital movement of the satellite, information related to the successor satellite needs to be included in the indication message transmitted between the satellites. The indication message may include a variety of information not only according to the orbital movement of the satellite, but also according to the type of the satellite or the capability of the terminal. According to one embodiment, the indication message may include information related to the orbital type of the satellite included in the path. For example, the indication message may include information related to the orbital type of the source satellite (e.g., the first satellite 801). The orbital type may represent LEO, MEO, or GEO. For example, the indication message may include information related to the orbital type of the target satellite (e.g., the fifth satellite 805). The orbital type may represent LEO, MEO, or GEO. According to one embodiment, the indication message may include information related to the satellite type. The satellite type may indicate whether it is a regenerative payload or a transparent payload. According to one embodiment, the indication message may include information related to the speed of the satellite. For example, the speed of the satellite may be indicated by the velocity vector of each axis in the XYZ coordinate system, as indicated in the ephemeris information. According to one embodiment, the indication message may include information related to the number of beams for each satellite. Even the same satellite may support different coverage areas through different beams. The indication message may include information related to the number of beams provided by the satellite and / or information related to each beam (eg, beam ID).

[0194] According to an embodiment, the indication message may include at least one of the items listed in the following table. The items may be defined for each satellite. The indication message may be transmitted via an inter-satellite link (eg, ISL), i.e., from a specific satellite to another satellite.

[0195] [Table 5]

[0196] information illustrate Satellite ID Successor satellite ID Beam ID information of the successor satellite Duration information Information about the time that the successor satellite stays in the coverage area of ​​the corresponding satellite Community Information Cell information of the successor satellite in case of regenerative payload (handover) Track Type LEO, GEO, MEO Satellite Type Transparent payload or regenerated payload speed Satellite speed Number of beams The number of beams each satellite can support Beam ID Beam identifier for each satellite

[0197] As a non-limiting example, at least one of the items in Table 5 may be included in an indication message together with at least one of the items in Table 4 for use.

[0198] Fig.11 An example of path setting using ISL is shown. In the following, the path setting is described as being performed by a source satellite (e.g., the first satellite 801), but the embodiments of the present disclosure are not limited thereto. The path setting may be performed by a separate network entity that manages the satellite (e.g., NTN gateway 223, NTN gateway 630, AMF 640, HLR server), or may also be performed by a master satellite that controls another satellite among the satellites.

[0199] Reference Fig.11 , the first satellite 801 may identify a first set 1102 of neighboring satellites adjacent to the first satellite 801. The first satellite 801 may identify a second satellite 802 among the satellites in the first set 1102. For example, the first satellite 801 identifies the second satellite 802 among the satellites in the first set 1102 based on the time the satellite stays in the coverage area, the direction information between the source satellite and the target satellite, the beam information of each satellite, and the ephemeris information (e.g., position-velocity information and orbit information) of each satellite. The second satellite 802 may identify a second set 1103 of neighboring satellites adjacent to the second satellite 802. The second satellite 802 may identify a third satellite 803 among the satellites in the second set 1103. For example, the second satellite 802 identifies the third satellite 803 among the satellites in the second set 1103 based on the time the satellite stays in the coverage area, the direction information between the source satellite and the target satellite, the beam information of each satellite, and the ephemeris information (e.g., position-velocity information and orbit information) of each satellite. The third satellite 803 may identify a third set 1104 of neighboring satellites that are adjacent to the third satellite 803. The third satellite 803 may identify a fourth satellite 804 among the satellites of the third set 1104. For example, the third satellite 803 identifies the fourth satellite 804 among the satellites of the third set 1104 based on the time the satellite stays in the coverage area, the direction information between the source satellite and the target satellite, the beam information of each satellite, and the ephemeris information (e.g., position-velocity information and orbit information) of each satellite. The fourth satellite 804 may identify a fourth set (not shown) of neighboring satellites that are adjacent to the fourth satellite 804. The fourth satellite 804 may identify a fifth satellite 805 among the satellites of the fourth set. For example, the fourth satellite 804 identifies the fifth satellite 805 among the satellites of the fourth set based on the time the satellite stays in the coverage area, the direction information between the source satellite and the target satellite, the beam information of each satellite, and the ephemeris information (e.g., position-velocity information and orbit information) of each satellite.

[0200] Fig.11, an example of setting a satellite path between the first satellite 801 and the fifth satellite 805 according to a certain algorithm is described in. As a non-limiting example, the path can be set by an external network entity (e.g., NTN gateway 223, NTN gateway 630, AMF 640, HLR server, or a master satellite in a satellite group). The first satellite 801 can send a message to the external network entity for requesting path setting. For example, since AMF 640 knows the ephemeris information of each satellite, the position information of the corresponding satellite can be identified within 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 send information related to the list to each satellite. For example, AMF 640 can send information related to the second satellite 802 to the first satellite 801. AMF 640 can send information related to the third satellite 803 to the second satellite 802. AMF 640 can send information related to the fourth satellite 804 to the third satellite 803. The AMF 640 may transmit information related to the fifth satellite 805 to the fourth satellite 804. For another example, the AMF 640 may transmit information related to a list of satellites on a path to the first satellite 801, the second satellite 802, the third satellite 803, the fourth satellite 804, and the fifth satellite 805, respectively.

[0201] As a non-limiting example, the satellite path can be set in an ad-hoc network mode. In the ad-hoc network mode, the network topology can be dynamically formed by autonomous signaling between satellites. For example, the first satellite 801 can broadcast an indication message. The satellite (e.g., the second satellite 802) that receives the indication message can broadcast the indication message. The indication message is repeatedly transmitted through the link between satellites, and the indication message can reach the fifth satellite 805 as the target satellite. For the ad-hoc network mode, the indication message can also include information related to the number of hops.

[0202] According to an embodiment, the satellite selection criteria for path setting may include the following factors. The distance between satellites and the range of communication, the current traffic load of each satellite, the prediction of the orbital movement path of the satellite, and the communication delay time may be considered. Based on these criteria, the best path may be selected.

[0203] If ISL setup on the selected path fails, the following alternative procedures can be performed. First, a neighboring satellite of the next priority can be selected. Subsequently, an alternative path re-search can be performed. If necessary, a detour path can be set up through the ground gateway.

[0204] Fig.12 An example of RRC configuration for path indication is shown.

[0205] Reference Fig.12 , the first satellite 801 may send RRC configuration information 1201 to the first UE 811. According to one embodiment, the RRC configuration information 1201 may include information related to the first satellite 801 and the successor satellite of the first satellite 801. For example, the RRC configuration information 1201 may include ephemeris information related to each satellite. According to one embodiment, the RRC configuration information 1201 may be provided through an SI message of a system information block (SIB). For example, the RRC configuration information 1201 may have the following format.

[0206] [Table 6]

[0207]

[0208] "ntn-Config" indicates the parameters for accessing the wireless network through NTN access, and the following table (for example, Table 7) may be referred to. "t-service" may indicate time information related to the time point at which a cell provided by the NTN quasi-Earth fixed system interrupts service for the area it is currently responsible for. "referenceLocation" indicates the reference position of the service cell provided by the NTN quasi-Earth fixed system. "distanceThresh" indicates the distance from the reference position of the service cell, and may be used for location-based measurements in the RRC IDLE or RRC INACTIVE states. "ntn-NeighCellConfigList" may indicate information about neighboring cells of a cell provided by a satellite (for example, satellite 260, satellite 620).

[0209] [Table 7]

[0210]

[0211]

[0212] "epochTime" indicates the epoch time of NTN support information. When specifically provided through SIB or provided through dedicated signaling, the epoch time indicates the start time of the DL subframe and may display the number of the subframe signaled together with the system frame number (SFN) and the support information. As a non-limiting example, for higher granularity, "epochTime" may include an information element indicating a symbol in addition to a subframe. The IE may indicate one of 0 to 13 and indicate one of 14 symbols.

[0213] "ntn-UlSyncValidityDuration" is the validity duration of the auxiliary information (e.g., ephemeris information, common TA parameters) set by the network. In other words, the validity duration indicates the maximum time that the support information can be applied without obtaining new NTN support information. The above 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 uplink timing are inconsistent. "ta-Info" may include information for TA (timing advance). The information for TA may include "ta-Common" (common TA controlled by the network), "ta-CommonDrift" indicating the drift rate of the common TA, and "ta-CommonDriftVariant" indicating the variation of the drift rate. "ntn-PolarizationDL" and "ntn-PolarizationUL" represent the polarization information in DL and UL, respectively. "ephemerisInfo" indicates ephemeris information, and may be exemplified as the following table (eg, Table 8). "ta-Report" indicates that TA reporting is activated during RRC connection establishment, RRC connection resume, and RRC connection reestablishment.

[0214] [Table 8]

[0215]

[0216] "positionX", "positionY", and "positionZ" represent the position state vector of the earth-centered, earth-fixed, ECEF coordinate system in the xyz coordinate system, respectively. The unit is meter, and one step represents 1.3 meters. For example, the actual value may be the field value * 1.3. "velocityX", "velocityY", and "velocityZ" represent the velocity state vector of ECEF in the xyz coordinate system, respectively. One step represents 0.06 m / s (meters per second). For example, the actual value may be the field value * 0.06. "semiMajorAxis" is the semi-major axis, "eccentricity" is the eccentricity, "periapsis" is the periapsis, "longitude" is the longitude, "inclination" is the inclination, and "meanAnomaly" is the mean anomaly, which represents the ratio of the elliptical orbit period passed by the orbiting object after passing the periapsis.

[0217] According to an embodiment, the RRC configuration information may include information related to a list of satellites (i.e., satellites of a satellite link) on a path set from a source satellite (e.g., the first satellite 801) to a target satellite (e.g., the fifth satellite 805). For example, the RRC configuration information may 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. In response to a request message for a call connection of the first UE 811, the RRC configuration information may be provided to the first UE 811.

[0218] According to an embodiment, the RRC configuration information may include information related to the duration of the 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 continuously move along the orbit, but also the orbits are not parallel to each other, so the best link in three-dimensional space may change over time. Therefore, the duration associated with the path may be limited. The RRC configuration information may include information related to the validity time of the corresponding satellite link.

[0219] Fig.13 Examples of components of a satellite (eg, satellite 260, satellite 620) are shown. Terms such as "unit" and "device" used below refer to a unit that processes at least one function or action, which can be implemented by hardware or software or a combination of hardware and software.

[0220] Reference Fig.13, the satellite 620 may 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 uplinks a baseband signal into an RF band signal and transmits it through an antenna, and downlinks the RF band signal received through the antenna into a baseband signal. For example, the transceiver 1301 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

[0221] The transceiver 1301 may include multiple transceiver paths. Further, the transceiver 1301 may include an antenna unit. The transceiver 1301 may include at least one antenna array consisting of multiple antenna elements. From a hardware perspective, the transceiver 1301 may be composed of digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). Here, the digital circuits and the analog circuits may be implemented in one package. Furthermore, the transceiver 1301 may include multiple RF chains. The transceiver 1301 may perform beamforming. In order to give the signal to be transmitted and received a directionality corresponding to the setting of the processor 1303, the transceiver 1301 may apply a beamforming weighting value to the signal. According to one embodiment, the transceiver 1301 may include an RF block (or RF unit).

[0222] The transceiver 1301 may transmit and receive signals on a radio access network. For example, the transceiver 1301 may transmit a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., a cell-specific reference signal (CRS), a demodulation reference signal (DM (demodulation)-RS)), system information (e.g., MIB, SIB, remaining system information (RMSI), other system information (OSI)), a configuration message, control information or downlink data, etc. And, for example, the transceiver 1301 may receive an uplink signal. The uplink signal may include a random access associated signal (e.g., a random access preamble (RAP) (or message 1 (Msg1)), a message 3 (Msg3), a reference signal (e.g., a sounding reference signal (SRS), DM-RS) or a power headroom report (PHR). Fig.13 Only transceiver 1301 is shown in FIG. 6 , but according to other implementation examples, satellite 620 may include more than two RF transceivers.

[0223] The processor 1303 controls the overall operation of the satellite 620. The processor 1303 may be referred to as a control unit. For example, the processor 1303 transmits and receives signals through the transceiver 1301. Also, the processor 1303 records and reads data in the memory 1305. In addition, the processor 1303 may execute the functions of the protocol stack required in the communication specification. Fig.13 Only the processor 1303 is shown in the figure, and according to other implementation examples, the satellite 620 may include more than two processors. In the processor 1303, the instruction set or code stored in the memory 1305 may be an instruction / code or a storage space storing instructions / code that is at least temporarily resident in the processor 1303, or a part of the circuitry of the processor 1303. In addition, the processor 1303 may include various modules for performing communication. The processor 1303 may control the satellite 620 to make it perform the actions of the embodiment.

[0224] The memory 1305 stores data such as basic programs, application programs, setting information, etc. for the operation of the satellite 620. The memory 1305 may be referred to as a storage unit. The memory 1305 may be composed of a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. In addition, the memory 1305 provides the stored data according to a request of the processor 1303. According to an embodiment, the memory 1305 may include a memory for conditions, instructions, or setting values ​​associated with the SRS transmission method.

[0225] Fig.14 An example of constituent elements of a terminal (e.g., UE 610) is shown. The terminal illustrates UE 610. UE 610 can be connected to a gNB (e.g., gNB 120) that provides NR access through NTN.

[0226] Reference Fig.14 , the UE 610 may include at least one processor 1401, at least one memory 1403, and at least one transceiver 1405. In the following, although a constituent element is described in the singular, implementation of a plurality of constituent elements or sub-constituent elements is not excluded.

[0227] The processor 1401 controls the overall actions of the UE 610. For example, the processor 1401 records data in the memory 1403 and reads it. For example, the processor 1401 sends and receives signals through the transceiver 1405. Fig.14 A processor is shown in the figure, but the embodiments of the present disclosure are not limited thereto. The UE 610 may include at least one processor in order to execute the embodiments of the present disclosure. The processor 1401 may be referred to as a control unit or a control means. According to the embodiment, the processor 1401 may control the UE 610 to execute at least one of the actions or methods of the embodiments of the present disclosure.

[0228] The memory 1403 may store data such as basic programs, applications, setting information, etc. used for the actions of the UE 610. The memory 1403 may store various data used by at least one constituent element (e.g., transceiver 1405, processor 1401). The data may include, for example, input data or output data about software and its related instructions. The memory 1403 may be composed of a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. In addition, the memory 1403 may provide the stored data according to the request of the processor 1401.

[0229] The transceiver 1405 performs functions for transmitting and receiving signals through a wireless channel. For example, the transceiver 1405 performs a conversion function between a baseband signal and a bit string according to the physical layer specification of the system. For example, when transmitting data, the transceiver 1405 encodes and modulates the transmission bit string to generate a complex value symbol. And, when receiving data, the transceiver 1405 restores the received bit string by demodulating and decoding the baseband signal. And, the transceiver 1405 up-converts the baseband signal into an RF band signal and transmits it through the antenna, and down-converts the RF band signal received through the antenna into a baseband signal.

[0230] To this end, the transceiver 1405 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), etc. In addition, the transceiver 1405 may include multiple transceiver paths. Further, the transceiver 1405 may include at least one antenna array consisting of multiple antenna elements. From a hardware perspective, the transceiver 1405 may be composed of a digital unit and an analog unit, and the analog unit may be composed of multiple sub-units according to the operating power, operating frequency, etc.

[0231] The transceiver 1405 sends and receives signals as described above. Therefore, the transceiver 1405 may be referred to as a "sending unit", a "receiving unit" or a "transceiver unit". Furthermore, in the following description, the sending and receiving performed through a wireless channel, a backhaul network, an optical cable, an Ethernet, or other wired paths are used to include the meaning of the processing performed by the transceiver 1405 as described above. According to one embodiment, the transceiver 1405 may provide an interface for performing communication with other nodes within the network. That is, the transceiver 1405 may convert a bit string sent from the UE 610 to other nodes (e.g., other access nodes, other base stations, upper nodes, core networks, etc.) into a physical signal, and convert a physical signal received from other nodes into a bit string.

[0232] When describing the embodiments of the present disclosure, the terms and messages defined in 3GPP are used to describe the messages between the satellite (e.g., satellite 620) and the terminal (e.g., UE 610), but the embodiments of the present disclosure are not limited thereto. Of course, terms and messages having the same technical meanings as the above terms and messages may be used instead. In addition, as a satellite, not only gNB, gNB-CU, gNB-DU, but also gNB-CU-CP (control plane) (e.g., Figure 3A C-plane) and gNB-CU-UP (user plane) (e.g., Figure 3BU-plane)). Furthermore, a satellite can be used not only as a base station (e.g., gNB) or a part of a base station (e.g., DU), but also a core network entity (e.g., AMF 235) connected to the base station can be implemented as a satellite. For example, communication between a satellite and a satellite 620 as an AMF 235 action can also be defined. For example, a logical node including an AMF 235 and a gNB 120 can be implemented in one satellite. As implemented in software through network virtualization, separate logical nodes can be deployed within one hardware satellite.

[0233] In an embodiment, a device for providing a satellite for NTN access is provided. The device may include: a memory including instructions, at least one processor, and at least one transceiver. When the instructions are executed by the at least one processor, the device may perform the following operations: receiving a request message for a call connection from a terminal through the at least one transceiver, identifying a target satellite corresponding to a target terminal of the request message, determining whether it is possible to directly link to the target satellite, and when it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite through the at least one transceiver, and when it is not possible to directly link to the target satellite, identifying a second satellite that can form a direct link with the satellite, and sending the indication message to the second satellite through the at least one transceiver.

[0234] For example, the indication message may 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 and the beam information of the target satellite.

[0235] For example, the indication message may include direction information indicating a direction vector from the satellite to the target satellite.

[0236] For example, the indication message may include a list of satellites on a path from the satellite to the target satellite.

[0237] For example, the indication message may include information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

[0238] For example, the information related to the first successor satellite may include at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to the time the first successor satellite stays in the first coverage area of ​​the satellite. The information related to the second successor satellite may include at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to the time the second successor satellite stays in the second coverage area of ​​the target satellite.

[0239] For example, the request message may include identification information of the terminal and identification information of the target terminal.

[0240] In an embodiment, a method performed by a satellite for providing NTN access is provided. The method performed by the satellite for providing NTN access may include the following steps: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether it is possible to directly link to the target satellite, when it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, when it is not possible to directly link to the target satellite, identifying a second satellite that can form a direct link with the satellite, and sending the indication message to the second satellite.

[0241] For example, the indication message may 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 and the beam information of the target satellite.

[0242] For example, the indication message may include direction information indicating a direction vector from the satellite to the target satellite.

[0243] For example, the indication message may include a list of satellites on a path from the satellite to the target satellite.

[0244] For example, the indication message may include information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

[0245] For example, the information related to the first successor satellite may include at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to the time the first successor satellite stays in the first coverage area of ​​the satellite. The information related to the second successor satellite may include at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to the time the second successor satellite stays in the second coverage area of ​​the target satellite.

[0246] For example, the request message may include identification information of the terminal and identification information of the target terminal.

[0247] In an embodiment, a non-transitory storage medium is provided. The non-transitory storage medium may include a memory, and the memory includes instructions. When the instructions are executed by a processor of a satellite, the satellite may perform the following operations: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether it is possible to directly link to the target satellite, and when it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, and when it is not possible to directly link to the target satellite, identifying a second satellite that can form a direct link with the satellite, and the second satellite sending the indication message.

[0248] For example, the indication message may 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 and the beam information of the target satellite.

[0249] For example, the indication message may include direction information indicating a direction vector from the satellite to the target satellite.

[0250] For example, the indication message may include a list of satellites on a path from the satellite to the target satellite.

[0251] For example, the indication message may include information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

[0252] For example, the information related to the first successor satellite may include at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to the time the first successor satellite stays in the first coverage area of ​​the satellite. The information related to the second successor satellite may include at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to the time the second successor satellite stays in the second coverage area of ​​the target satellite.

[0253] For example, the request message may include identification information of the terminal and identification information of the target terminal.

[0254] The methods of the embodiments described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0255] In the case of software implementation, 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 to be executable by one or more processors in the electronic device. The one or more programs include instructions for causing the electronic device to implement the method of the embodiment described in the claims or specification of the present disclosure.

[0256] Such a program (software module, software) may be stored in a non-volatile memory including a random access memory, a flash memory, a read only memory (ROM), an electrically erasable programmable read only memory (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), a digital versatile disc (DVDs) or other forms of optical storage devices, a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of part or all of them. Furthermore, each constituent memory may include a plurality of them.

[0257] Furthermore, the program may be stored in an attachable storage device that can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device may be accessed to the device for executing the embodiments of the present disclosure through an external port. Furthermore, an additional storage device on the communication network may also be accessed to the device for executing the embodiments of the present disclosure.

[0258] In the above-mentioned specific embodiments of the present disclosure, the constituent elements included in the present disclosure are expressed as singular or plural according to the specific embodiments proposed. However, the expression of singular or plural is selected for convenience of explanation and is suitable for the proposed situation. The present disclosure is not limited to singular or plural constituent elements, and even if the constituent element is expressed as plural, it can also be constituted as singular, or even if the constituent element is expressed as singular, it can also be constituted as plural.

[0259] In addition, although the above description of the present disclosure is described with respect to specific embodiments, various modifications may be implemented without departing from the scope of the present disclosure.

Claims

1. An apparatus for providing a satellite for accessing a non-terrestrial network (NTN), wherein: include: Memory, including instructions, at least one processor, and at least one transceiver; When the instructions are executed by the at least one processor, the device performs the following operations: receiving, by the at least one transceiver, a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether a direct link to the target satellite is possible, When it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite through the at least one transceiver, When a direct link to the target satellite is not possible, identifying a second satellite that can form a direct link with the satellite, The indication message is sent to the second satellite through the at least one transceiver.

2. The apparatus for providing a satellite for providing access to a non-terrestrial network NTN according to claim 1, wherein: The indication message includes at least one of identification information of the satellite, identification information of the target satellite, identification information of the terminal, identification information of the target terminal, beam information of the satellite, and beam information of the target satellite.

3. The apparatus for providing a satellite for providing access to a non-terrestrial network (NTN) according to claim 1, wherein: The indication message includes direction information indicating a direction vector from the satellite to the target satellite.

4. The apparatus for providing a satellite for providing access to a non-terrestrial network (NTN) according to claim 1, wherein: The indication message includes a list of satellites on a path from the satellite to the target satellite.

5. The apparatus for providing a satellite for providing access to a non-terrestrial network (NTN) according to claim 1, wherein: The indication message includes information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

6. The apparatus for providing a satellite for accessing a non-terrestrial network (NTN) according to claim 5, wherein: The information related to the first successor satellite includes at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to a time during which the first successor satellite stays in a first coverage area of ​​the satellite. The information related to the second successor satellite includes at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to a time that the second successor satellite stays in a second coverage area of ​​the target satellite.

7. The apparatus for providing satellite access to a non-terrestrial network (NTN) according to claim 1, wherein: The request message includes identification information of the terminal and identification information of the target terminal.

8. A method performed by a satellite for providing access to a non-terrestrial network (NTN), wherein: The steps include: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether a direct link to the target satellite is possible, When it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, When a direct link to the target satellite is not possible, identifying a second satellite that can form a direct link with the satellite, and The indication message is sent to the second satellite.

9. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 8, wherein: The indication message includes at least one of identification information of the satellite, identification information of the target satellite, identification information of the terminal, identification information of the target terminal, beam information of the satellite, and beam information of the target satellite.

10. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 8, wherein: The indication message includes direction information indicating a direction vector from the satellite to the target satellite.

11. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 8, wherein: The indication message includes a list of satellites on a path from the satellite to the target satellite.

12. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 8, wherein: The indication message includes information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

13. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 12, wherein: The information related to the first successor satellite includes at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to a time during which the first successor satellite stays in a first coverage area of ​​the satellite. The information related to the second successor satellite includes at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to a time that the second successor satellite stays in a second coverage area of ​​the target satellite.

14. The method performed by a satellite for providing access to a non-terrestrial network (NTN) according to claim 8, wherein: The request message includes identification information of the terminal and identification information of the target terminal.

15. A non-transitory storage medium, wherein: include: Memory, including instructions; When the instructions are executed by a processor of the satellite, the satellite performs the following operations: receiving a request message for a call connection from a terminal, identifying a target satellite corresponding to a target terminal of the request message, determining whether a direct link to the target satellite is possible, When it is possible to directly link to the target satellite, sending an indication message for a call connection between the terminal and the target terminal to the target satellite, When a direct link to the target satellite is not possible, identifying a second satellite that can form a direct link with the satellite, The second satellite sends the indication message.

16. The non-transitory storage medium according to claim 15, wherein: The indication message includes at least one of identification information of the satellite, identification information of the target satellite, identification information of the terminal, identification information of the target terminal, beam information of the satellite, and beam information of the target satellite.

17. The non-transitory storage medium according to claim 15, wherein: The indication message includes direction information indicating a direction vector from the satellite to the target satellite.

18. The non-transitory storage medium according to claim 15, wherein: The indication message includes a list of satellites on a path from the satellite to the target satellite.

19. The non-transitory storage medium according to claim 15, wherein: The indication message includes information related to a first successor satellite that will provide service to a first coverage area of ​​the satellite and information related to a second successor satellite that will provide service to a second coverage area of ​​the target satellite.

20. The non-transitory storage medium according to claim 19, wherein: The information related to the first successor satellite includes at least one of identification information of the first successor satellite, beam information of the first successor satellite, cell information of the first successor satellite, and information related to a time during which the first successor satellite stays in a first coverage area of ​​the satellite. The information related to the second successor satellite includes at least one of identification information of the second successor satellite, beam information of the second successor satellite, cell information of the second successor satellite, and information related to a time that the second successor satellite stays in a second coverage area of ​​the target satellite.

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