Communication device and communication method

Abstract

To provide a communication device and a communication method that maintain feeder link and service link connectivity in a non-terrestrial network.SOLUTION: In a method, a non-terrestrial network (NTN) system using a plurality of ground stations controls the establishment of feeder link and service link communications. In a retransmission type NTN, when a ground station 61C and a user terminal 10 are located within a range corresponding to the same beam or are located within less than a predetermined distance, the service link of the user terminal 10 is prioritized to use the beam and connect a non-terrestrial object 63 and the user terminal 10. Further, another ground station 61D located at a geographical position corresponding to a beam different from that of the ground station 61C establishes a feeder link with the non-terrestrial object 63 in preference to the ground station 61C.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a communication device and a communication method. [Background technology]

[0002] The standardization project 3GPP (Third Generation Partnership Project) is currently studying and creating technical specifications for NR (New Radio) (also known as "5G"), the successor to LTE (Long Term Evolution), that will provide high-capacity systems, high data transmission speeds, low latency, simultaneous connection of a large number of terminals, low cost, and power saving.

[0003] Furthermore, in recent years, technologies have been considered that enable coverage of mountainous areas, remote areas, oceans, and other areas using non-terrestrial networks (NTN) using high altitude platform stations (HAPS, or high altitude pseudo satellites) and the like (see, for example, Non-Patent Documents 1 and 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TR 38.821 V16.0.0 (2019-12) [Non-Patent Document 2] Konishi et al., "A Study on Downlink Spectrum Sharing in HAPS Mobile Communication Systems," Institute of Electronics, Information and Communication Engineers General Conference, B-17-1, 2020 Summary of the Invention [Problem to be solved by the invention]

[0005] In a non-terrestrial network that uses multiple beams to support feeder links and service links at the same frequency, multiplexing by beams is difficult when the distance between a terminal and a terrestrial station is short.

[0006] The present disclosure aims to maintain connectivity of feeder links and service links in non-terrestrial based networks. [Means for solving the problem]

[0007] According to the disclosed technology, a communication unit that uses the same frequency to establish a feeder link with a ground station and a service link with a terminal, and a control unit that executes control to establish communication related to the feeder link and the service link when the distance between the ground station and the terminal is smaller than a threshold value. The control unit establishes the feeder link with another ground station when the distance between the ground station and the terminal is smaller than a threshold value. A communications device is provided. Effect of the Invention

[0008] According to the disclosed technique, it is possible to maintain the connections of feeder links and service links in a non-terrestrial network. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a system configuration of a wireless communication system 1 according to an embodiment. [Diagram 2] FIG. 1 is a diagram illustrating an example (1) of the configuration of a non-terrestrial network 60 according to an embodiment. [Diagram 3] FIG. 13 is a diagram illustrating a configuration example (2) of a non-terrestrial network 60 according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of a functional configuration of a user terminal 10 according to an embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of a functional configuration of a non-terrestrial network 60 according to an embodiment. [Figure 6] FIG. 1 is a diagram showing an example (1) of a non-terrestrial network 60. [Figure 7]FIG. 2 is a diagram showing an example (2) of a non-terrestrial network 60. [Figure 8] FIG. 1 is a diagram showing an example (1) of a non-terrestrial network 60 according to an embodiment. [Figure 9] FIG. 2 is a diagram showing an example (2) of a non-terrestrial network 60 according to an embodiment. [Figure 10] FIG. 2 is a diagram showing an example (3) of a non-terrestrial network 60 according to an embodiment. [Figure 11] FIG. 11 is a diagram showing an example (4) of a non-terrestrial network 60 according to an embodiment. [Figure 12] FIG. 2 is a diagram illustrating an example of the hardware configuration of each device of a non-terrestrial network 60, each device of a terrestrial network 50, and a user terminal 10 according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments described below are merely examples, and embodiments to which the present disclosure is applicable are not limited to the following embodiments.

[0011] A publicly known technology may be used as appropriate in the wireless communication system according to the embodiment of the present disclosure. The publicly known technology may be, for example, 5G and Beyond 5G. Note that the technology of the present disclosure is not limited to 5G and is applicable to any wireless communication system.

[0012] (System Configuration) 1 is a diagram illustrating a system configuration of a wireless communication system 1 according to an embodiment. The wireless communication system 1 according to the embodiment includes a user terminal 10A and a user terminal 10B (hereinafter, when there is no need to distinguish between them, they are also simply referred to as "user terminals 10"), and a communication network 20. Note that the number of user terminals 10 is not limited to the example in FIG. 1.

[0013] The user terminal 10 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, a communication module for M2M (Machine-to-Machine), etc. A user of the user terminal 10 may have a predetermined contract with a mobile network operator (Mobile Network Operator, MNO) so as to use various communication services of a communication network 20 provided by the mobile network operator. A medium for identifying a subscriber (e.g., a Subscriber Identity Module (SIM) card) distributed (lent) by the mobile network operator may be inserted into the user terminal 10.

[0014] The user terminal 10 may use various communication services provided by the communication network 20 using the identification information recorded in the SIM card. The various communication services may include a data service for transmitting and receiving data via the Internet. The various communication services may also include a voice service for making and receiving voice calls. The voice service may include, for example, a service that enables making and receiving voice calls using VoNR (Voice over New Radio), which is a voice call technology on a 5G network. The voice service may also include, for example, a service that enables making and receiving voice calls by switching (falling back) the communication network that accommodates the user terminal 10 to a 4G or 3G communication network when making and receiving voice calls.

[0015] (Regarding communication network 20) The communication network 20 provides various services such as voice services and data services to the user terminal 10. The communication network 20 includes a core network 30 and a RAN (Radio Access Network) 40. The core network 30 may, for example, manage information on users (subscribers) of the user terminal 10, manage sessions such as voice calls, transmit data via the Internet, etc.

[0016] The communication network 20 may be, for example, a 5G network of a non-stand alone (NSA) system that uses 4G (including LTE or LTE-A) EPC (Evolved Packet Core) as the core network 30 and uses en-gNBs, which are 5G base stations, as some base stations as the RAN 40. In this case, the communication network 20 may transmit and receive control signals using eNBs, which are 4G base stations, and transmit and receive data using en-gNBs, which are 5G base stations.

[0017] Furthermore, the communication network 20 may be a 5G network of a Stand Alone (SA) system that uses a 5G core network (5GC) as the core network 30 and uses gNBs, which are 5G base stations, as at least some of the base stations as the RAN 40. In this case, the communication network 20 may transmit and receive control signals and data using, for example, the gNBs.

[0018] The RAN 40 includes a terrestrial network 50 and a non-terrestrial network 60. The terrestrial network 50 is a network that directly communicates wirelessly with the user terminal 10 via a base station 51 installed in a facility on the ground, for example.

[0019] The non-terrestrial networks (NTN) 60 are, for example, networks that perform wireless communication with the user terminal 10 via objects (non-terrestrial objects) other than objects installed on the ground. The non-terrestrial networks 60 may use, for example, a high altitude platform station (HAPS), an aircraft such as an unmanned aerial vehicle, or a spacecraft such as a satellite as a repeater (relay station) or a base station. For example, when a HAPS that resides at a fixed location at an altitude of about 20 km is used, the non-terrestrial networks 60 can form a wide coverage area on the ground (land) with a cell radius of 50 km or more.

[0020] The base station 61 of the non-terrestrial network may be composed of a CU (Centralized Unit) 65 and a DU (Distributed Unit) 66. The CU 65 may be called an aggregation node, and the DU 66 may be called a distributed node. The CU 65 and the DU 66 may be connected via a fronthaul interface, and the CU and the DU may be separated, for example, between an upper PHY layer and a lower PHY layer, between a PHY layer and a MAC (Media Access Control) layer, or between a RLC (Radio Link Control) layer and a PDCP (Packet Data Convergence Protocol) layer. Similarly, the base station 51 of the terrestrial network may be composed of a CU 55 and a DU 56.

[0021] The DU 66 and the DU 56 establish a wireless connection with the user terminal 10. The CU 65 and the CU 55 are connected to the core network 30. The CU 65 and the CU 55 may transmit a control signal and a data signal received from the user terminal 10 to the core network 30, or may transmit a control signal and a data signal received from the core network 30 to the user terminal.

[0022] <Retransmission (transparent) type example> Fig. 2 is a diagram for explaining an example (part 1) of the configuration of a non-terrestrial network 60 according to an embodiment. As shown in Fig. 2, the non-terrestrial network 60 may be a retransmission (transparent) type NTN in which a non-terrestrial object has a repeater. In the example of Fig. 2, the non-terrestrial network 60 (60A) has a base station 61A installed on the ground, an NTN gateway 62A installed on the ground, and a non-terrestrial object 63A.

[0023] 2, data transmitted from the core network 30 to the user terminal 10 is first transmitted from the core network 30 to the base station 61A. The base station 61A then transmits the received data to a non-terrestrial object 63A as a downlink wireless signal via the NTN gateway 62A. The non-terrestrial object 63A then relays (transfers) the received downlink wireless signal to the user terminal 10 via a repeater.

[0024] Furthermore, data transmitted from the user terminal 10 to the core network 30 is first transmitted from the user terminal 10 to a non-terrestrial object 63A as an uplink wireless signal. The non-terrestrial object 63A then relays (transfers) the received uplink wireless signal to the NTN gateway 62A using a repeater. The NTN gateway 62A then transmits the received uplink wireless signal to the base station 61A wirelessly or via a wired connection. The base station 61A then transmits the data received from the NTN gateway 62A to the core network 30.

[0025] <Example of regenerative type> Fig. 3 is a diagram for explaining a second example of the configuration of a non-terrestrial network 60 according to an embodiment. As shown in Fig. 3, the non-terrestrial network 60 may be a regenerative NTN in which a non-terrestrial object has a base station. In the example of Fig. 3, the non-terrestrial network 60 (60B) has an NTN gateway 62B installed on the ground, and a non-terrestrial object 63B having a base station 61B.

[0026] 3, data transmitted from the core network 30 to the user terminal 10 is first transmitted by radio waves (wireless signals) from the core network 30 to the base station 61B of the non-terrestrial object 63B by the NTN gateway 62B. Then, the base station 61B of the non-terrestrial object 63B generates a downlink wireless signal based on the received data, and transmits the generated wireless signal to the user terminal 10.

[0027] Moreover, data transmitted from the user terminal 10 to the core network 30 is first transmitted by an uplink wireless signal from the user terminal 10 to the non-terrestrial object 63B. Then, the base station 61B of the non-terrestrial object 63B transmits the received data to the core network 30 via the NTN gateway 62B.

[0028] (Device configuration) An example of the functional configuration of the user terminal 10 and the non-terrestrial network 60 will be described with reference to FIG. 4 and FIG.

[0029] <User terminal 10> Fig. 4 is a diagram showing an example of a functional configuration of the user terminal 10 according to the embodiment. As shown in Fig. 4, the user terminal 10 has a transmitting unit 110, a receiving unit 120, and a control unit 130. Each of these units may be realized, for example, by cooperation between hardware such as a processor of the user terminal 10 and software installed in the user terminal 10.

[0030] 4 is merely an example. As long as the operation according to the present embodiment can be performed, the names of the functional divisions and functional units may be any. For example, the transmitting unit 110 and the receiving unit 120 may be collectively referred to as a communication unit or the like.

[0031] The transmitting unit 110 transmits data to the communication network 20. The receiving unit 120 receives data from the communication network 20. The receiving unit 120 also receives information relating to control of the feeder link and the service link, for example.

[0032] The control unit 130 performs various controls in the user terminal 10. The control unit 130 controls wireless communication with the base station 61, etc., based on information related to control of the feeder link and the service link received by the receiving unit 120, for example.

[0033] <Non-terrestrial network 60> Fig. 5 is a diagram showing an example of a functional configuration of a non-terrestrial network 60 according to an embodiment. As shown in Fig. 5, a device such as a base station 61 included in the non-terrestrial network 60 has a transmitting unit 210, a receiving unit 220, and a control unit 230. Each of these units may be realized by, for example, cooperation between hardware such as a processor of a device such as a base station included in the non-terrestrial network 60 and software installed in the device.

[0034] 5 is merely an example. As long as the operation according to the present embodiment can be performed, the functional divisions and the names of the functional units may be any. For example, the transmitting unit 210 and the receiving unit 220 may be collectively referred to as a communication unit or the like.

[0035] The transmitter 210 transmits data to the user terminal 10 and the core network 30. The receiver 220 receives data from the user terminal 10 and the core network 30. The receiver 220 receives, for example, information relating to control of the feeder link and the service link.

[0036] The control unit 230 performs various controls in the non-terrestrial network 60. The control unit 230 controls wireless communication with the user terminal 10, for example, based on information related to control of the feeder link and the service link received by the receiving unit 220.

[0037] (process) FIG. 6 is a diagram showing an example (1) of a non-terrestrial network 60. Using multiple beams, it is possible to apply different beams to the feeder link and the service link and support them at the same frequency. FIG. 6 shows an example in which, in a retransmission type NTN, a beam transmitted from a non-terrestrial object 63 is applied to a feeder link with a terrestrial station 61 and a beam transmitted from a non-terrestrial object 63 is applied to a service link with a user terminal 10. In FIG. 6, the size of one beam on the ground is typically shown by an ellipse. In the following description, it is assumed that the non-terrestrial object 63 has a repeater 67.

[0038] Fig. 7 is a diagram showing an example (2) of a non-terrestrial network 60. Fig. 7 shows a case in which a beam transmitted from a non-terrestrial object 63 and applied to a feeder link with a terrestrial station 61 and a beam applied to a service link with a user terminal 10 are the same beam in a retransmission type NTN. As shown in Fig. 7, when the user terminal 10 is located near the terrestrial station 61, the beam transmitted from the non-terrestrial object 63 overlaps with the feeder link and the service link, making multiplexing difficult at the same frequency.

[0039] FIG. 8 is a diagram showing an example (1) of a non-terrestrial network 60 according to an embodiment. A non-terrestrial network system using a plurality of terrestrial stations 61 performs control to establish communication of a feeder link and a service link. As shown in FIG. 8, in a retransmission type NTN, when a terrestrial station 61C and a user terminal 10 are located within a range corresponding to the same beam or are located within a predetermined distance, the service link of the user terminal 10 is given priority to use the beam, and a non-terrestrial object 63 is connected to the user terminal 10. Furthermore, another terrestrial station 61D located at a geographical position corresponding to a beam different from that of the terrestrial station 61C is given priority over the terrestrial station 61C to establish a feeder link with the non-terrestrial object 63.

[0040] In other words, the non-terrestrial object 63 may establish communication of the feeder link and the service link by first determining a beam to be applied as a priority for connecting the service link, and second connecting to an earth station 61 that can establish a feeder link to which a beam that can be multiplexed with the service link is applied.

[0041] However, for example, the non-terrestrial object 63 may be informed of and be able to determine the geographical positions of the user terminal 10 and the ground station 61, and may be able to determine the corresponding beams of the user terminal 10 and the ground station 61.

[0042] Fig. 9 is a diagram showing an example (2) of a non-terrestrial network 60 according to an embodiment. As shown in Fig. 9, when a terrestrial station 61 and a user terminal 10 are located within a range corresponding to the same beam or within a predetermined distance, a non-terrestrial object 63 may establish communication of the feeder link and the service link by division multiplexing the feeder link and the service link with radio resources of time, frequency or code.

[0043] Fig. 10 is a diagram showing an example (3) of a non-terrestrial network 60 according to an embodiment. As shown in Fig. 10, when a terrestrial station 61 and a user terminal 10 are located within a range corresponding to the same beam or are located within a predetermined distance, a non-terrestrial object 63 may establish communication of the feeder link and the service link by multiplexing the feeder link and the service link into the same radio resource by NOMA (Non-orthogonal multiple access).

[0044] That is, the transmitter of the user terminal 10 or non-terrestrial object 63 may transmit the service link signal at a relatively high power density, and after canceling the service link signal at the receiver of the ground station 61 or non-terrestrial object 63, the receiver of the ground station 61 or non-terrestrial object 63 may demodulate the feeder link signal.

[0045] 11 is a diagram showing an example (4) of a non-terrestrial network 60 according to an embodiment. As shown in FIG. 10, when a terrestrial station 61 and a user terminal 10 are located within a range corresponding to the same beam or are located within a predetermined distance, the terrestrial station 61 and the user terminal 10 may be controlled to communicate directly with each other without passing through a non-terrestrial object 63.

[0046] (Hardware configuration) The block diagrams (FIGS. 4 and 5) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically combined, or may be realized using two or more devices that are physically or logically separated and directly or indirectly connected (e.g., using wires, wirelessly, etc.) and these multiple devices. The functional blocks may be realized by combining the one device or the multiple devices with software.

[0047] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, mapping, assignment, etc. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. In either case, as described above, there is no particular limitation on the method of realization.

[0048] For example, each device of the non-terrestrial network 60, each device of the terrestrial network 50, and the user terminal 10 in an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 12 is a diagram showing an example of a hardware configuration of each device of the non-terrestrial network 60, each device of the terrestrial network 50, and the user terminal 10 according to the embodiment. Each device of the non-terrestrial network 60, each device of the terrestrial network 50, and the user terminal 10 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0049] In the following description, the term "apparatus" may be interpreted as a circuit, a device, a unit, etc. The hardware configurations of each apparatus of the non-terrestrial network 60, each apparatus of the terrestrial network 50, and the user terminal 10 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0050] The functions of each device in the non-terrestrial network 60, each device in the terrestrial network 50, and each device in the user terminal 10 are realized by loading specific software (programs) onto hardware such as a processor 1001, a memory device 1002, etc., so that the processor 1001 performs calculations, controls communications by the communication device 1004, and controls at least one of the reading and writing of data in the memory device 1002 and the auxiliary memory device 1003.

[0051] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 130, control unit 230, etc. may be realized by the processor 1001.

[0052] Moreover, the processor 1001 reads out a program (program code), a software module, data, or the like from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and executes various processes according to the program. As the program, a program that causes a computer to execute at least a part of the operations described in the above-mentioned embodiment is used. For example, the control unit 130 of the user terminal 10 shown in FIG. 4 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 230 of the non-terrestrial network 60 shown in FIG. 5 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed by two or more processors 1001 simultaneously or sequentially. The processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunication line.

[0053] The storage device 1002 is a computer-readable recording medium, and may be configured by at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a Random Access Memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The storage device 1002 can store a program (program code), software modules, etc. that are executable to implement a communication method according to an embodiment of the present disclosure.

[0054] The auxiliary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the auxiliary storage device 1003.

[0055] The communication device 1004 is hardware (transmission and reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to realize at least one of, for example, Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, a transmission and reception antenna, an amplifier unit, a transmission and reception unit, a transmission line interface, etc. may be realized by the communication device 1004. The transmission and reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated from each other.

[0056] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0057] In addition, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0058] Furthermore, each device of the non-terrestrial network 60, each device of the terrestrial network 50, and the user terminal 10 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc., and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0059] According to the above-described embodiment, even if the user terminal 10 and the terrestrial station 61 are close to each other in a non-terrestrial network, it is possible to perform control to maintain the connections of both the service link and the feeder link.

[0060] That is, in a non-terrestrial network, the connections of the feeder links and the service links can be maintained.

[0061] (Summary of the embodiment) As described above, according to an embodiment of the present invention, there is provided a communication device having a communication unit that establishes a feeder link with a ground station and a service link with a terminal using the same frequency, and a control unit that executes control to establish communication related to the feeder link and the service link when the distance between the ground station and the terminal is smaller than a threshold value.

[0062] With the above-mentioned configuration, even if the user terminal 10 and the terrestrial station 61 are close to each other in a non-terrestrial network, it is possible to perform control to maintain the connections of both the service link and the feeder link.

[0063] The control unit may establish the feeder link with another ground station when the distance between the ground station and the terminal is smaller than a threshold value. With this configuration, in a non-terrestrial network, even when the user terminal 10 and the ground station 61 are close to each other, it is possible to control to maintain the connection of both the service link and the feeder link.

[0064] The control unit may establish the feeder link with another ground station corresponding to a beam different from the beam corresponding to the ground station when the distance between the ground station and the terminal is smaller than a threshold value. With this configuration, in a non-terrestrial network, even when the user terminal 10 and the ground station 61 are close to each other, it is possible to control to maintain the connection of both the service link and the feeder link.

[0065] When the distance between the ground station and the terminal is smaller than a threshold, the control unit may multiplex the radio resources of the feeder link and the radio resources of the service link by time, frequency, or code division. With this configuration, even when the user terminal 10 and the ground station 61 are close to each other in a non-terrestrial network, it is possible to control to maintain the connection of both the service link and the feeder link.

[0066] The control unit may establish the feeder link and the service link using a signal multiplexed by applying non-orthogonal multiple access when the distance between the earth station and the terminal is smaller than a threshold value. With this configuration, in a non-terrestrial network, even when the user terminal 10 and the earth station 61 are close to each other, it is possible to control to maintain the connection of both the service link and the feeder link.

[0067] Furthermore, according to an embodiment of the present invention, there is provided a communication method in which a communication device executes a communication procedure for establishing a feeder link with an earth station and a service link with a terminal using the same frequency, and a control procedure for executing control to establish communication related to the feeder link and the service link when the distance between the earth station and the terminal is smaller than a threshold value.

[0068] With the above-mentioned configuration, even if the user terminal 10 and the terrestrial station 61 are close to each other in a non-terrestrial network, it is possible to perform control to maintain the connections of both the service link and the feeder link.

[0069] (Supplementary embodiment) Although the embodiments of the present disclosure have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, modifications, alternatives, replacements, and the like. Although specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, those numerical values ​​are merely examples and any appropriate values ​​may be used. The division of items in the above description is not essential to the present disclosure, and matters described in two or more items may be used in combination as necessary, and matters described in one item may be applied to matters described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operations of multiple functional units may be physically performed by one part, or the operations of one functional unit may be physically performed by multiple parts. The order of the processing procedures described in the embodiments may be changed as long as there is no contradiction. For convenience of explaining the processes, each device of the non-terrestrial network 60, each device of the terrestrial network 50, and the user terminal 10 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. Software operated by a processor included in each device of the non-terrestrial network 60 and each device of the terrestrial network 50 according to an embodiment of the present disclosure, and software operated by a processor included in the user terminal 10 according to an embodiment of the present disclosure may each be stored in a random access memory (RAM), a flash memory, a read-only memory (ROM), an EPROM, an EEPROM, a register, a hard disk (HDD), a removable disk, a CD-ROM, a database, a server, or any other suitable storage medium.

[0070] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination of these. Furthermore, the RRC signaling may be called an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0071] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other suitable systems, and next-generation systems extended based on these. In addition, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) may be applied.

[0072] The steps, sequences, flowcharts, etc. of each aspect / embodiment described herein may be reordered unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0073] In the present disclosure, a specific operation performed by a base station such as the non-terrestrial network 60 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a user terminal 10 may be performed by at least one of the base station and other network nodes other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, the other network node may be a combination of multiple other network nodes (e.g., MME and S-GW).

[0074] The information or signals described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0075] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0076] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0077] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0078] Additionally, software, instructions, information, etc. may be transmitted or received over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired and / or wireless technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave, etc.), then these wired and / or wireless technologies are included within the definition of transmission media.

[0079] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0080] In addition, the terms described in this disclosure and the terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Also, a signal may be a message. Also, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0081] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0082] In addition, the information, parameters, etc. described in the present disclosure may be represented using absolute values, may be represented using relative values ​​from a predetermined value, or may be represented using other corresponding information. For example, a radio resource may be indicated by an index.

[0083] The names used for the above-mentioned parameters are not limiting in any way. Moreover, the formulas using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0084] In the present disclosure, terms such as "base station (BS)", "wireless base station", "base station device", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier", etc. may be used interchangeably. A base station may also be referred to by terms such as a macro cell, a small cell, a femto cell, a pico cell, etc.

[0085] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or a base station subsystem that provides communication services in this coverage.

[0086] In this disclosure, the terms "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "terminal", etc. may be used interchangeably.

[0087] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0088] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may include a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0089] Furthermore, the base station in the present disclosure may be read as a user terminal. For example, each aspect / embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of user terminals 10 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the user terminal 10 may be configured to have the functions of the above-mentioned base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, an uplink channel, a downlink channel, etc. may be read as a side channel.

[0090] Similarly, the user terminal in the present disclosure may be interpreted as a base station. In this case, the base station may be configured to have the functions of the above-mentioned user terminal.

[0091] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), and the like. In addition, "judgment" and "decision" can include considering resolving, selecting, choosing, establishing, comparing, etc., to be a "judgment" or "decision." In other words, "judgment" and "decision" can include considering some action to be a "judgment" or "decision." In addition, "judgment" can be interpreted as "assuming," "expecting," "considering," etc.

[0092] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0093] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0094] Any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0095] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0096] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0097] A radio frame may consist of one or more frames in the time domain. Each of the one or more frames in the time domain may be referred to as a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0098] Numerology may be a communication parameter that applies to the transmission and / or reception of a signal or channel, such as SubCarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame structure, a particular filtering operation performed by the transceiver in the frequency domain, a particular windowing operation performed by the transceiver in the time domain, etc.

[0099] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) in the time domain. A slot may be a time unit based on numerology.

[0100] A slot may include multiple minislots. Each minislot may be composed of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may be composed of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0101] A radio frame, a subframe, a slot, a minislot, and a symbol each represent a time unit for transmitting a signal. The radio frame, the subframe, the slot, the minislot, and the symbol may each be referred to by a different name.

[0102] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in the existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit expressing the TTI may be called a slot, a minislot, or the like, instead of a subframe.

[0103] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0104] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) in which a transport block, a code block, a code word, etc. are actually mapped may be shorter than the TTI.

[0105] In addition, when one slot or one minislot is called TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit of scheduling. Also, the number of slots (minislots) constituting the minimum time unit of scheduling may be controlled.

[0106] A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel. 8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, etc.

[0107] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0108] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of the numerology, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0109] In addition, the time domain of the RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. Each of one TTI, one subframe, etc. may be composed of one or more resource blocks.

[0110] Note that one or more RBs may be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, or the like.

[0111] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0112] A Bandwidth Part (BWP), which may also be referred to as a fractional bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a numerology on a carrier, where the common RBs may be identified by the index of the RBs relative to a common reference point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0113] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0114] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell", "carrier", etc. in this disclosure may be replaced with "BWP".

[0115] The above-mentioned structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0116] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0117] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0118] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

[0119] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0120] 1. Wireless communication systems 10 User terminal 20. Communication Networks 30 Core Network 50 Terrestrial Network 51 Base station 55 CU 56DU 60 Non-terrestrial networks 60A Non-terrestrial network 60B Non-terrestrial networks 61 Base station 61A base station 61B base station 62 NTN Gateway 62A NTN Gateway 62B NTN Gateway 63 Non-terrestrial objects 63A Non-terrestrial objects 63B Non-terrestrial objects 65 CU 66DU 67 Repeater 110 Transmitter 120 Receiving unit 130 Control section 210 Transmitter 220 Receiving unit 230 Control Unit

Claims

1. a communication unit that establishes a feeder link with a ground station and a service link with a terminal using the same frequency; a control unit that executes control to establish communication related to the feeder link and the service link when a distance between the ground station and the terminal is smaller than a threshold value; The control unit is a communication device that establishes the feeder link with another ground station when the distance between the ground station and the terminal is smaller than a threshold value.

2. The communication device according to claim 1 , wherein the control unit, when a distance between the ground station and the terminal is smaller than a threshold value, establishes the feeder link with another ground station corresponding to a beam different from the beam corresponding to the ground station.

3. The communication device according to claim 1 , wherein the control unit multiplexes the radio resources of the feeder link and the radio resources of the service link by time, frequency or code division when the distance between the ground station and the terminal is smaller than a threshold value.

4. The communication device according to claim 1 , wherein the control unit establishes the feeder link and the service link using signals multiplexed by applying non-orthogonal multiple access when a distance between the ground station and the terminal is smaller than a threshold value.

5. A communication procedure for establishing a feeder link with a ground station and a service link with a terminal using the same frequency; a control procedure for executing control to establish communication related to the feeder link and the service link when a distance between the ground station and the terminal is smaller than a threshold; and, if the distance between the ground station and the terminal is smaller than a threshold, a procedure of establishing the feeder link with another ground station.

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