Base station and communication method

Abstract

This base station includes: an acquisition unit that acquires position information of each of a terminal and a plurality of radio relay devices; a control unit that, on the basis of the position information, selects a radio relay device to be controlled included in the plurality of radio relay devices; and a transmission unit that transmits radio waves to the selected radio relay device.

Description

Base station and communication method

[0001] The present invention relates to a base station and a communication method in a wireless communication system.

[0002] In 3GPP (registered trademark) (3rd Generation Partnership Project), a wireless communication method called 5G or NR (New Radio) (hereinafter, this wireless communication method will be referred to as "NR") is being studied in order to realize a larger system capacity, a higher data transmission speed, a lower latency in wireless sections, etc. In 5G, various wireless technologies and network architectures are being studied to meet the requirement of achieving a throughput of 10 Gbps or more while reducing the latency in wireless sections to 1 ms or less (for example, Non-Patent Document 1).

[0003] Next-generation communications are expected to use high-frequency bands. The characteristics of these bands require improvements in communication quality due to the reduction in the number of scatterers, the reduction in the shadowing effect, and the increase in distance attenuation. It is expected that beam control and environments that guarantee communication quality will be required.

[0004] For example, in high frequency bands, there is a problem that blind zones are likely to occur due to the strong directional nature of radio waves, etc. Therefore, methods have been attempted to improve communication quality in a multipath environment by using passive repeaters, active reflectors (RIS: Reconfigurable Intelligent Surface), smart repeaters that receive, amplify, and re-emit signals, etc. (e.g., Non-Patent Document 2).

[0005] 3GPP TS 38.300 V17.6.0 (2023-09) NTT Docomo, "White Paper: 5G Advancements and 6G" (2021-02, Version 3.0), available online at: https: / / www.nttdocomo.co.jp / binary / pdf / corporate / technology / whitepaper_6g / DOCOMO_6G_White_PaperJP_20210203.pdf

[0006] When operating a radio relay device such as a reflector or smart repeater that relays radio waves by reflecting or transmitting them from a radio wave source such as a base station to a radio wave receiving destination such as a terminal, it has been difficult to improve capacity by increasing the number of spatial multiplexes in an environment with few reflected waves.

[0007] The present invention has been made in view of the above points, and has as its object to improve communication quality in a wireless communication system by using a wireless relay device.

[0008] According to the disclosed technology, a base station is provided that has an acquisition unit that acquires location information of a terminal and a plurality of wireless relay devices, a control unit that selects a wireless relay device to be controlled that is included in the plurality of wireless relay devices based on the location information, and a transmission unit that transmits radio waves to the selected wireless relay device.

[0009] According to the disclosed technique, communication quality can be improved in a wireless communication system by using a wireless relay device.

[0010] 1 is a diagram for explaining a wireless communication system in an embodiment of the present invention. FIG. 1 is a diagram illustrating an example of the functional configuration of a base station 10 in an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the functional configuration of a terminal 20 in an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of the functional configuration of a wireless relay device 30 in an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of an operation of the wireless relay device 30 in an embodiment of the present invention. FIG. 5 is a diagram illustrating an example of communication in a high frequency band. FIG. 6 is a diagram illustrating an example of a reflective wireless relay device 30 in an embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a transparent wireless relay device 30 in an embodiment of the present invention. FIG. 8 is a diagram illustrating an example (1) of communication in an embodiment of the present invention. FIG. 9 is a diagram illustrating an example (2) of communication in an embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a communication environment in an embodiment of the present invention. FIG. 11 is a diagram illustrating an example (1) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 12 is a diagram illustrating an example (2) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 13 is a diagram illustrating an example (3) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 14 is a diagram illustrating an example (4) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 15 is a diagram illustrating an example (5) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 16 is a diagram illustrating an example (6) of installing a RIS in a mobility device in an embodiment of the present invention. FIG. 17 is a diagram illustrating an example (1) of installing a RIS in a stationary object in an embodiment of the present invention. FIG. 18 is a flowchart for explaining an example of controlling a 1 is a diagram illustrating an example of a hardware configuration of a base station 10, a terminal 20, or a wireless relay device 30 according to an embodiment of the present invention. 2 is a diagram illustrating an example of a configuration of a vehicle 2001 according to an embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0012] In the operation of the wireless communication system according to the embodiment of the present invention, existing technology is used as appropriate. However, the existing technology is, for example, the existing LTE, but is not limited to the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR), unless otherwise specified.

[0013] In addition, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel) used in existing LTE are used. This is for convenience of description, and similar signals, functions, etc. may be called by other names. In addition, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even if a signal is used in NR, it is not necessarily stated as "NR-".

[0014] Furthermore, in the embodiment of the present invention, the duplex method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or another method (for example, flexible duplex, etc.).

[0015] Furthermore, in the embodiments of the present invention, "configuring" radio parameters etc. may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0016] Fig. 1 is a diagram for explaining a wireless communication system according to an embodiment of the present invention. As shown in Fig. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. There may be a plurality of base stations 10 and a plurality of terminals 20.

[0017] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain, and the time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. Furthermore, a transmission time interval (TTI) in the time domain may be a slot or a subslot, or a subframe.

[0018] The base station 10 is capable of performing carrier aggregation, which aggregates multiple cells (multiple CCs (component carriers)) to communicate with the terminal 20. In carrier aggregation, one primary cell (PCell) and one or more secondary cells (SCells) are used.

[0019] The base station 10 transmits synchronization signals, system information, and the like to the terminal 20. The synchronization signals are, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, via NR-PBCH or PDSCH, and is also referred to as broadcast information. As shown in FIG. 1, the base station 10 transmits control signals or data to the terminal 20 via DL (Downlink) and receives control signals or data from the terminal 20 via UL (Uplink). Note that, here, signals transmitted via control channels such as PUCCH and PDCCH are referred to as control signals, and signals transmitted via shared channels such as PUSCH and PDSCH are referred to as data, but these terms are merely examples.

[0020] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. As shown in FIG. 1, the terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. The terminal 20 may be referred to as a UE, and the base station 10 may be referred to as a gNB.

[0021] The terminal 20 can perform carrier aggregation, which aggregates multiple cells (multiple CCs) to communicate with the base station 10. In carrier aggregation, one primary cell and one or more secondary cells are used. Also, a PUCCH-SCell having a PUCCH may be used.

[0022] In the wireless communication system according to the embodiment of the present invention, the base station 10 is, for example, a wireless base station operated in 5G or 6G and forms a cell. The cell is a relatively large cell and is called a macrocell.

[0023] Base station 10A to base station 10D are base stations operated in 5G or 6G. Base station 10A to base station 10D form cells CA to D, respectively, which are smaller in size than a macro cell. Cells A to D may also be called small cells, macro cells, or the like. As shown in FIG. 1, cells A to D may be formed so as to be included in the macro cell.

[0024] A macrocell may generally be interpreted as a communication area with a radius of several hundred meters to several tens of kilometers that is covered by one base station, and a small cell may be interpreted as a general term for a cell that has low transmission power and covers an area smaller than that of a macrocell.

[0025] The base station 10 and the base stations 0A to 10D may be referred to as gNodeB (gNB) or BS (Base Station), etc. The terminal 20 may be referred to as UE or MS, etc. Furthermore, the specific configuration of the wireless communication system including the number and types of base stations and terminals is not limited to the example shown in FIG.

[0026] Furthermore, the wireless communication system is not necessarily limited to a wireless communication system conforming to 5G or 6G. For example, the wireless communication system may be a next-generation wireless communication system such as 6G or a wireless communication system conforming to LTE.

[0027] As an example, the base station 10 and the base stations 10A-10D perform wireless communication according to 5G or 6G with the terminal 20. The base station 10, the base station 10A-10D, and the terminal 20 may support massive multiple-input multiple-output (MIMO) that generates a more directional beam by controlling radio signals transmitted from multiple antenna elements, carrier aggregation (CA) that uses a bundle of multiple component carriers (CCs), dual connectivity (DC) that simultaneously communicates between the terminal 20 and each of two NG-RAN nodes, and IAB (Integrated Access and Backhaul) that integrates wireless backhaul between wireless communication nodes such as gNBs and wireless access to the terminal 20.

[0028] The wireless communication system may also support higher frequency bands than the following frequency ranges (FR) defined in 3GPP Release 15. For example, FR1 may support 410 MHz-7.125 GHz, and FR2 may support 24.25 GHz-52.6 GHz. Furthermore, the wireless communication system may support a frequency band exceeding 52.6 GHz up to 114.25 GHz. This frequency band may be called the millimeter wave band.

[0029] Here, a base station 10 that supports massive MIMO can transmit beams. Massive MIMO generally refers to MIMO communication using an antenna with 100 or more antenna elements, which enables faster wireless communication than conventional methods by multiplexing multiple streams. Advanced beamforming is also possible. The beam width can be dynamically changed depending on the frequency band used or the status of the terminal 20. Furthermore, the use of narrow beams can increase the received signal power through beamforming gain. Furthermore, effects such as reduced interference and more effective use of wireless resources are expected.

[0030] The wireless communication system may also include a wireless relay device 30. In the embodiment of the present invention, the wireless relay device 30 may be, for example, a reflector (RIS), a phase-controlled reflector, a passive repeater, an IRS (Intelligent Reflecting Surface), or the like. Specific examples of the reflector (RIS: Reconfigurable Intelligent Surface) may include what is called a metamaterial reflector, a dynamic metasurface, a metasurface lens, or the like (see, for example, Non-Patent Document 2).

[0031] In an embodiment of the present invention, the wireless relay device 30 relays a wireless signal transmitted from, for example, the base station 10A. In the description of the embodiment of the present invention, "relay" may refer to at least one of "reflection," "transmission," "concentration (concentrating radio waves at approximately one point)," and "diffraction." The terminal 20 can receive the wireless signal relayed by the wireless relay device 30. Furthermore, the wireless relay device 30 may relay a wireless signal transmitted from the terminal 20 or a wireless signal transmitted from the base station 10.

[0032] As an example, the wireless relay device 30 can change the phase of a wireless signal relayed to the terminal 20. From this perspective, the wireless relay device 30 may be called a variable-phase reflector. Note that in the present embodiment, the wireless relay device 30 may have the function of changing the phase of a wireless signal to relay it, but is not limited to this. The wireless relay device 30 may also be called a repeater, relay device, reflect array, IRS, transmit array, or the like.

[0033] In addition, in the embodiment of the present invention, the wireless relay device 30 such as a RIS may be called a battery-less device, a metamaterial functional device, an intelligent reflecting surface, a smart repeater, etc. As an example, the wireless relay device 30 such as a RIS or a smart repeater may be defined as having the functions shown in 1) to 5) below.

[0034] 1) The terminal 20 may have a function for receiving signals transmitted from the base station 10. The signals may be DL signals such as SSB (SS / PBCH block), PDCCH, PDSCH, DM-RS (Demodulation Reference Signal), PT-RS (Phase Tracking Reference Signal), CSI-RS (Channel Status Information Reference Signal), and RIS-dedicated signals. The terminal 20 may have a function for receiving signals carrying information related to metamaterial functions. Note that the terminal 20 may have a transmission function for transmitting the signals to the terminal 20. The SSB may be a signal including a synchronization signal and broadcast information.

[0035] 2) It may have a function of transmitting signals to the base station 10. The signals may be UL signals such as PRACH, PUCCH, PUSCH, DM-RS, PT-RS, SRS, and RIS-dedicated signals. It may have a function of transmitting information related to metamaterial functions. It may also have a receiving function of receiving the signals from the terminal 20.

[0036] 3) It may have a function of frame synchronization with the base station 10. It may also have a function of frame synchronization with the terminal 20.

[0037] 4) The base station 10 or the terminal 20 may have a function of reflecting a signal transmitted from the base station 10 or the terminal 20. For example, the reflection function may be a function related to phase change, a function related to beam control (for example, a function related to control of TCI (Transmission Configuration Indication)-state, QCL (Quasi Co Location), beam selection and application, and spatial filter / precoding weight selection and application). 5) The base station 10 or the terminal 20 may have a function of changing the power of a signal transmitted from the base station 10 or the terminal 20. For example, the power change function may be power amplification.

[0038] Furthermore, "receive and transmit" or "relay" in a wireless relay device 30 such as a RIS or smart repeater may mean that up to function A below is performed, but transmission is performed without performing function B below. Function A: A phase shifter is applied. Function B: A compensation circuit (e.g., amplifier, filter) is not used.

[0039] As another example, Function A: Apply a phase shifter and a compensation circuit. Function B: Do not perform frequency conversion.

[0040] In addition, when the phase is changed, the amplitude may be amplified in the wireless relay device 30 such as a RIS. Furthermore, "relaying" in the wireless relay device 30 such as a RIS may mean transmitting a received signal as is without performing processing at the layer 2 or layer 3 level, transmitting a received signal at the physical layer level as is, or transmitting a received signal as is without interpreting the signal (in which case, the phase may be changed, the amplitude may be amplified, etc.).

[0041] (Device Configuration) Next, a functional configuration example of the base station 10, terminal 20, and wireless relay device 30 that executes the processes and operations according to the embodiment of the present invention will be described. The base station 10, terminal 20, and wireless relay device 30 each include functions for executing the embodiments described below. However, the base station 10, terminal 20, and wireless relay device 30 may each include only one of the functions of the embodiments.

[0042] <Base Station 10> Fig. 2 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 2, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 2 is merely an example. As long as the operations related to the embodiment of the present invention can be performed, the names of the functional divisions and functional units may be any. The transmitting unit 110 and the receiving unit 120 may be called a communication unit.

[0043] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signal. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL data, etc. to the terminal 20. The transmitter 110 also transmits setting information, etc., which will be described in the embodiments.

[0044] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads out the information from the storage device as needed. The control unit 140 performs, for example, resource allocation and overall control of the base station 10. Note that the functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120. The transmitting unit 110 and the receiving unit 120 may also be referred to as a transmitter and a receiver, respectively. Note that the control unit 140 may include an acquiring unit that acquires information.

[0045] <Terminal 20> Fig. 3 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 3, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 3 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention. The transmitting unit 210 and the receiving unit 220 may be called a communication unit.

[0046] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The transmitter 210 also transmits HARQ-ACK, and the receiver 220 receives setting information and the like described in the embodiments.

[0047] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220 in a storage device, and reads it out from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The control unit 240 performs overall control of the terminal 20, etc. Note that the function unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and the function unit related to signal reception in the control unit 240 may be included in the receiving unit 220. The transmitting unit 210 and the receiving unit 220 may also be called a transmitter and a receiver, respectively.

[0048] <Wireless Relay Device 30> Fig. 4 is a diagram showing an example of the functional configuration of the wireless relay device 30 according to the embodiment of the present invention. As shown in Fig. 4, the wireless relay device 30 has a transmitting unit 310, a receiving unit 320, a control unit 330, a variable unit 340, and an antenna unit 350. The functional divisions and names of the functional units may be any names as long as they can perform the operations according to the embodiment of the present invention. The transmitting unit 310 and the receiving unit 320 may be referred to as a communication unit.

[0049] The antenna unit 350 includes at least one antenna connected to the variable unit 340. For example, the antenna unit 350 may be arranged as an array antenna. In the embodiment of the present invention, the antenna unit 350 may be particularly referred to as a relay antenna. The variable unit 340 and the antenna unit 350 may also be referred to as a relay unit.

[0050] The variable unit 340 is connected to the antenna unit 350 and can change the phase, load, amplitude, etc. For example, the variable unit 340 may be a variable phase shifter, a phase shifter, an amplifier, etc. For example, by changing the phase of the radio waves that reach the relay antenna from the radio wave generating source, it is possible to change the direction or beam of the radio waves.

[0051] The control unit 330 is a control means for controlling the variable unit 340. In an embodiment of the present invention, the control unit 330 functions as a control unit that controls the relay state when relaying radio waves from the base station 10 or the terminal 20 without signal interpretation. Here, the control unit 330 may change the relay state based on control information received from the base station 10 or the terminal 20 via the communication unit, or may change the relay state based on the reception state of the radio waves from the base station 10 or the terminal 20. For example, the control unit 330 may select appropriate reception beams and transmission beams (directions) based on control information such as SSB, and control the variable unit 340. Similarly, the control unit 330 may select an appropriate combination of reception direction and transmission direction based on criteria such as the highest reception quality or the highest received power from the reception state, and control the variable unit 340.

[0052] Furthermore, in the embodiment of the present invention, the control unit 330 can control the variable unit 340 based on, for example, information about the propagation path between the terminal 20 or the base station 10A and the antenna unit 350 (including information estimated based on the reception state and control information; the same applies below). For example, the control unit 330 can use a known method such as an active repeater or RIS to relay radio waves received from the base station 10A to a specific direction such as the radio wave receiving destination (terminal 20 in this case) by changing the phase without using transmission power. Specifically, the control unit 330 uses the estimated propagation path information H ＰＴ and H ＲＰ Based on this, the wireless relay device 30 controls the phase of the wireless signal to relay it to the terminal 20 or the base station 10A. That is, by changing the phase of an array antenna or the like based on the same principle as beamforming, it is possible to relay radio waves in a specific direction. Note that the wireless relay device 30 controls (changes) only the phase of the wireless signal (radio wave) using the control unit 330, and may relay the signal without power supply, without amplifying the power of the relayed wireless signal.

[0053] In addition, in the embodiment of the present invention, the control unit 330 may acquire information based on the reception state. Furthermore, the receiving unit 320 may acquire control information from the base station 10A or the terminal 20. For example, the receiving unit 320 may receive various signals such as SSB (including the various signals exemplified in the above-mentioned functions) transmitted from the base station 10A or the terminal 20 as control information.

[0054] Furthermore, the control unit 330 calculates propagation path information (H ＰＴ and H ＲＰ ) may be estimated.

[0055] The propagation path information (propagation channel information) regarding each propagation path is specifically information such as amplitude or phase, and in the embodiment of the present invention, is information estimated regarding the propagation path of the radio wave arriving at the antenna unit 350. As an example, the control unit 330 may estimate the propagation path information of the antenna unit 350 based on a change in the received power when the phase of the variable unit 340 of the array-shaped antenna unit 350 is switched to quadrature, using a principle similar to that of I / Q (In-phase / Quadrature) detection.

[0056] 5 is a diagram illustrating an example of the operation of the wireless relay device 30 according to the embodiment of the present invention. As shown in FIG. 5, the wireless relay device 30 is located between the base station 10A (or another base station 10) and the terminal 20, and relays (reflects, transmits, collects, diffracts, etc.) wireless signals transmitted and received between the base station 10A and the terminal 20.

[0057] As a specific example, when the wireless quality is good, the base station 10A and the terminal 20 transmit and receive wireless signals directly without going through the wireless relay device 30. On the other hand, when the wireless quality deteriorates, for example, when there is an obstruction between the base station 10A and the terminal 20, the wireless relay device 30 relays the wireless signals transmitted and received between the base station 10A and the terminal 20.

[0058] Specifically, the wireless relay device 30 calculates propagation path information H between the radio wave generating source, such as the base station 10A or the terminal 20, and the relay antenna based on the change in the received power when the variable unit 340, such as a variable phase shifter, is controlled. ＰＴ , H ＲＴ The propagation path information H is estimated, and a variable unit 340 such as a variable phase shifter is controlled based on the estimated propagation path information to relay the radio signal to the radio wave receiving destination such as the terminal 20. ＰＴ , H ＲＴ The wireless relay device 30 may also relay a wireless signal to a radio wave receiving destination such as the base station 10A or the terminal 20 by controlling a variable unit 340 such as a variable phase shifter based on control information received from the base station 10A or the terminal 20.

[0059] Here, a propagation path or a propagation channel refers to an individual communication path for wireless communication, and in this case, refers to a communication path between each transmitting / receiving antenna (such as a base station antenna and a terminal antenna in the figure).

[0060] As an example, the wireless relay device 30 includes an antenna unit 350 having a small multi-element antenna compatible with massive MIMO, and a variable unit 340 having a variable phase changer or phase shifter that changes the phase of a wireless signal, essentially, radio waves, to a specific phase, and uses the variable unit 340 to control the phase of the radio waves relayed to the terminal 20 or base station 10A.

[0061] FIG. 6 is a diagram showing an example of communication in a high-frequency band. As shown in FIG. 6, when a high-frequency band of several GHz to several tens of GHz or more is used, blind zones are likely to occur due to the strong linearity of radio waves. When the base station 10A and the terminal 20 are line-of-sight, even when the high-frequency band is used, there is no impact on wireless communication between the base station 10A and the terminal 20. On the other hand, when the line-of-sight between the base station 10A and the terminal 20 is blocked by an obstruction, such as a building or a tree, the wireless quality is significantly degraded. In other words, when the terminal 20 moves into a blind zone blocked by an obstruction, communication may be interrupted.

[0062] Considering the existence of applications (such as remote control) that take advantage of high speed, large capacity, and low latency characteristics, it is important to eliminate blind spots, ensure communication within the wireless communication system, and ensure connections between base stations and terminals.

[0063] Therefore, technologies have been developed that can relay radio waves between the base station 10A and the terminal 20, such as radio wave propagation control devices such as RIS or smart repeaters. In this way, by controlling the propagation characteristics of the base station signal, it is possible to improve communication characteristics, expand coverage without the need for a signal source, and reduce installation and operation costs by adding base stations.

[0064] Conventional radio wave propagation control devices are classified into passive and active types. Passive types have the advantage of not requiring control information, but are unable to keep up with changes in the mobile object or environment. On the other hand, active types have the disadvantage of requiring control information and increasing overhead, but can variably control the propagation characteristics of radio waves by changing the load (phase) state of the control antenna, and can keep up with changes in the mobile object and environment.

[0065] There are two types of active radio wave propagation control devices and control methods: a feedback (FB) model and a propagation path information model. In the FB model, a variable radio wave propagation control device randomly changes the load (phase) state and has the terminal 20 or the like feed back the communication state, thereby searching for optimal conditions. On the other hand, in the propagation path information model, the load state is determined based on propagation path information between the base station and the radio wave propagation control device, making it possible to perform optimal radio wave propagation control. Either type can be applied to the embodiments of the present invention.

[0066] In addition, there are various types of relay methods, such as reflection, transmission, diffraction, and aggregation. In this embodiment, as an example, reflective and transmission type configurations will be described below (for diffraction and aggregation types, see Non-Patent Document 2, etc.).

[0067] FIG. 7 is a diagram illustrating an example of a reflective wireless relay device 30 according to an embodiment of the present invention. An example of the system configuration of the reflective wireless relay device 30 will be described using FIG. 7. FIG. 7 is a diagram illustrating the relationship between a transmitting antenna Tx of a base station 10A or the like, a relay antenna Sx of a transparent wireless relay device 30, and a receiving antenna Rx of a terminal 20 or the like. As shown in FIG. 7, the embodiment of the present invention uses MIMO as an example, in which there are multiple propagation paths between Tx and Sx and multiple propagation paths between Sx and Rx, and the wireless relay device 30 relays radio waves by controlling a variable unit 340 having a variable phase shifter or the like of the relay antenna Sx.

[0068] As shown in Figure 7, in the case of a reflective type, the array-like relay antennas are arranged facing the same direction, which allows the propagation path of the relay antenna to be estimated based on the reception state observed when the phase conditions of the relay antennas are changed multiple times.

[0069] FIG. 8 is a diagram illustrating an example of a transmission-type wireless relay device 30 according to an embodiment of the present invention. An example of the system configuration of a transmission-type wireless relay device 30 will be described using FIG. 8 . FIG. 8 illustrates the relationship between the transmitting antenna Tx of a base station 10A or the like, the relay antenna Sx of the transmission-type wireless relay device 30, and the receiving antenna Rx of a terminal 20 or the like. As shown in FIG. 8 , the embodiment of the present invention uses MIMO as an example, with multiple propagation paths between Tx and Sx and multiple propagation paths between Sx and Rx. As shown in the figure, the wireless relay device 30 relays radio waves arriving from one side to the other side via a variable unit 340 such as a variable phase shifter of the relay antenna Sx. As such, in the case of a transmission-type wireless relay device, the reference antenna on the left side of the figure and the relay antenna on the right side of the figure are arranged as a pair, facing in opposite directions, so that radio waves arriving from one side can be relayed to the other side. Whether the wireless relay device is a transmission-type or a reflection-type wireless relay device, a power detector or the like may be configured to detect the power received at the relay antenna to measure the reception status. Furthermore, the propagation path of the relay antenna can be estimated based on the received signal observed when the phase condition of the relay antenna is changed multiple times.

[0070] Future networks, such as 6G, will require even higher quality than 5G. For example, they will require ultra-high speeds on the order of tera bps, high reliability and low latency on the level of optical communications, etc. Furthermore, they will need to be designed with consideration for ultra-extended coverage, ultra-long distance communications, ultra-reliable communications, virtual cells, flexible networks, mesh networks, enhanced side links, and RIS or smart repeaters.

[0071] To achieve this quality, it is expected that very high frequencies, such as terahertz waves, will be used. For example, when using very high frequencies such as terahertz waves, the advantages are expected to be high speed due to the use of ultra-wideband and low latency due to short symbol lengths, but disadvantages are also expected, such as narrow coverage due to a large attenuation rate and reduced reliability due to high directivity. It is necessary to consider how to ensure redundancy for each location where 6G communication is required, i.e., how to increase communication transmission points.

[0072] As described above, the RIS reflects or transmits a beam transmitted from the base station 10 or the terminal 20 in a predetermined direction and delivers it to the terminal 20 or the base station 10. A passive RIS is a device that does not change control of the reflection angle or beam width, etc., according to the position of the mobile station, and does not require control information, but precise beam control is difficult. An active RIS is a device that changes control of the reflection angle and beam width, etc., according to the position of the mobile station, and allows precise beam control, but requires control information, which increases overhead. The RIS makes it possible to increase the number of transmission points for communication.

[0073] The RIS may be any of the names shown below in 1)-4), but is not limited to these: 1) Battery-less device 2) Metamaterial functional device 3) Intelligent reflecting surface 4) Smart repeater

[0074] The RIS may be any device that has a predetermined function, and the predetermined function may be, for example, at least one of the following functions 1) and 2).

[0075] 1) UE Functions A function for receiving signals transmitted from the base station 10 (e.g., DL signals, SSB, PDCCH, PDSCH, DM-RS, PT-RS, CSI-RS, RIS-dedicated signals). The receiving function may receive information related to the metamaterial function in 2) below. A function for transmitting signals to the base station 10 (e.g., UL signals, PRACH, PUCCH, PUSCH, DM-RS, PT-RS, SRS, RIS-dedicated signals). The transmitting function may transmit information related to the metamaterial function in 2) below. A function for frame synchronization with the base station 10.

[0076] 2) Metamaterial Function A function for reflecting a signal transmitted from the base station 10 or the terminal 20 (e.g., phase change). The signal may be reflected by changing the phase for each of the multiple reflecting elements possessed by the RIS, or a common phase change may be performed across multiple reflecting elements. A function related to beam control (e.g., TCI-state, QCL control function, selective application of beam, selective application of spatial filter / precoding weight). A function for changing the power of a signal transmitted from the base station 10 or the terminal 20 (e.g., power amplification). A different power change may be performed for each of the reflecting elements possessed by the RIS, or a common power change may be performed across multiple reflecting elements.

[0077] The "receive and transmit" in the RIS may mean reflecting radio waves / signals. The terms "base station" and "terminal" are used hereinafter, but are not limited to these and may be replaced with communication devices. The RIS may be replaced with a smart repeater, relay, etc.

[0078] For example, the RIS may operate under the following assumptions 1)-6): 1) The network operator configures the RIS; 2) The RIS is fixed and does not move; 3) The RIS relays signals from only one base station; 4) It can receive and transmit control signals; 5) It operates in half-duplex mode; and 6) It is a single RIS environment.

[0079] As described above, the use of RIS, smart repeaters, etc. is considered for the purpose of flexibly and inexpensively expanding the communication area of ​​a wireless communication network. A major difference between a RIS or smart repeater and an IAB node is that an IAB node performs baseband signal processing, while a RIS or smart repeater does not. To control the transmission direction or transmission beam of the RIS or smart repeater, a connection may be established between the base station 10 and the RIS or smart repeater, and configuration information may be defined in advance.

[0080] For example, the terminal 20 may operate as follows when using signals transmitted via a plurality of RISs or wireless relay devices 30 such as smart repeaters. In the following description, the RIS may be replaced with the smart repeater.

[0081] 9 is a diagram showing an example (1) of communication in an embodiment of the present invention. As shown in FIG. 9, Case 1 is assumed in which the existence of the RIS 30 is transparent, and the base station 10 and the terminal 20 are unaware that they are communicating via the RIS 30.

[0082] 10 is a diagram showing an example (2) of communication in an embodiment of the present invention. As shown in FIG. 10, a case 2 is assumed in which the presence of the RIS 30 is non-transparent, and the base station 10 and the terminal 20 recognize that they are communicating via the RIS 30.

[0083] In order to improve the performance of radio access networks for 5G Evolution and 6G, a new network topology (New Radio Network Topology, NRNT) is being considered, which increases the number of connection paths in the radio network by further expanding the heterogeneous network from the conventional cell-based radio access network configuration, overlapping multiple cell areas, and linking terminals including surrounding relay nodes.

[0084] NRNT is expected to expand coverage, increase the scope for path selection, expand the line-of-sight area, avoid obstructions, and increase the number of MIMO spatial multiplexings. NRNT's elemental technologies include metasurfaces or RIS, which are advanced versions of the reflector technology mentioned above. Metasurfaces are a type of artificial medium (metamaterial) that achieves arbitrary permittivity and permeability by periodically arranging structures that are small relative to the wavelength. As mentioned above, RIS is a device with variable in-plane scattering characteristics that can dynamically control the reflection or transmission direction.

[0085] To realize NRNT, we consider improving the radio wave environment of cellular networks. Metasurfaces, RIS, or relay devices can be installed on mobile or stationary objects to control the direction of radio wave propagation, thereby improving the reception quality of terminals. Note that the mobility can also be a moving object such as a vehicle.

[0086] On the other hand, in environments with few reflected waves, such as rural areas and highways, it is difficult to improve capacity by increasing the MIMO spatial multiplexing number. Furthermore, in communications with mobility, particularly with high-speed moving objects, Doppler shift occurs, resulting in degradation of communication quality. Doppler shift refers to a phenomenon in which the frequency of a wave, such as a sound wave or electromagnetic wave, is observed as a value different from the actual frequency when a relative speed exists between the source of the wave and the observer due to the movement of the source or observer of the wave.

[0087] 11 is a diagram showing an example of a communication environment in an embodiment of the present invention. As shown by the dashed line in FIG. 11, radio waves from base station 10A are basically radiated downward, so the radio waves from the base station have difficulty reaching the upper floors of a building. Furthermore, although radio waves from distant, high places are easy to reach because of the good visibility, because the distance to base station 10B is far, as shown by the dashed line in FIG. 11, radio waves from terminal 20 have difficulty reaching base station 10B.

[0088] Fig. 12 is a diagram showing an example (1) of installing a RIS in a mobility in an embodiment of the present invention. Fig. 13 is a diagram showing an example (2) of installing a RIS in a mobility in an embodiment of the present invention. As shown in Figs. 12 and 13, a RIS may be installed in a mobility to increase the number of reflected paths. As shown in Fig. 12, in order to minimize Doppler shift, radio waves may be emitted from the base station 10 perpendicular to the direction of movement to the RIS 30, which is moving in the same direction and at a similar speed as the terminal 20, and the RIS 30 may reflect or transmit the radio waves and radiate them to the target terminal 20.

[0089] 13 shows an example of operation on a highway, in which Car #1 equipped with RIS #1 emits radio waves to Car #5 equipped with a target terminal. For example, the following operations 1) to 6) may be performed.

[0090] 1) The terminal and RIS may periodically notify the base station of the location information of the terminal and RIS, or the vehicle, or the base station may estimate the location information. 2) The base station estimates the moving speed of the vehicle, i.e., the moving speed of the terminal or RIS, from the location information. The base station may also estimate the moving direction of the vehicle from the location information. 3) When transmitting radio waves from the base station (t ０ ), it is assumed that there is no direct path to the target terminal. 4) The base station selects the RIS that minimizes the sum of the relative speed between the base station and the RIS and the relative speed between the RIS and the target terminal. The relative speed may be calculated from the vehicle's moving speed and direction. 5) The base station may select multiple RISs. For example, multiple RISs may be selected in descending order of the sum of the relative speed between the base station and the RIS and the relative speed between the RIS and the target terminal. 6) The selected RIS reflects and / or transmits the radio waves transmitted from the base station to the target terminal. The base station may instruct the RIS to perform this operation.

[0091] Fig. 14 is a diagram showing an example (3) of installing a RIS in a mobility in an embodiment of the present invention. Fig. 15 is a diagram showing an example (4) of installing a RIS in a mobility in an embodiment of the present invention. As shown in Figs. 14 and 15, a RIS may be installed in a mobility to increase the number of reflected paths. As shown in Fig. 14, in order to minimize power loss and delay, the RIS 30B closest to the base station 10 may reflect or transmit the radio waves and radiate them to the target terminal 20.

[0092] 14 shows an example of operation on a highway, in which Car #3 equipped with a RIS emits radio waves to Car #5 equipped with a target terminal. For example, the following operations 1) to 4) may be performed.

[0093] 1) The terminal and the RIS may periodically notify the base station of the location information of the terminal and the RIS, or the vehicle, or the base station may estimate the location information. 2) When the base station transmits radio waves (t ０ ), it is assumed that there is no direct path to the target terminal. 3) From the location information, the base station selects the RIS that minimizes the sum of the distances between the base station and the RIS and between the RIS and the target. The base station may select multiple RISs. For example, multiple RISs may be selected in descending order of the sum. 4) The selected RIS reflects and / or transmits the radio waves transmitted from the base station to the target terminal. The base station may instruct the RIS to perform this operation.

[0094] 16 is a diagram showing an example (5) of installing a RIS in a mobility according to an embodiment of the present invention. As shown in FIG. 16, a RIS may be installed in the mobility to increase the number of reflected paths. As shown in FIG. 16, a RIS may be selected to minimize Doppler shift, power loss, and delay, and the radio waves may be reflected or transmitted to radiate them to the target terminal 20.

[0095] FIG. 16 shows an example of the operation on a highway, and for example, the following operations 1) to 6) may be executed.

[0096] 1) The terminal and RIS may periodically notify the base station of the location information of the terminal and RIS, or the vehicle, or the base station may estimate the location information. 2) The base station estimates the moving speed of the vehicle, i.e., the moving speed of the terminal or RIS, from the location information. The base station may also estimate the moving direction of the vehicle from the location information. 3) When transmitting radio waves from the base station (t ０ ), it is assumed that there is no direct path to the target terminal. 4) From the location information, the base station selects the RIS that minimizes the sum of the distances between the base station and the RIS and between the RIS and the target, and the sum of the relative speed between the base station and the RIS and the relative speed between the RIS and the target terminal. Note that the sum of the distances and the sum of the relative speeds may be multiplied by different weights to calculate the sum. Note that the relative speed may be calculated from the vehicle's moving speed and direction. 5) The base station may select multiple RISs. For example, multiple RISs may be selected in descending order of the sum of the smallest. 6) The selected RIS reflects and / or transmits radio waves transmitted from the base station to the target terminal. The base station may instruct the RIS to perform this operation.

[0097] 17 is a diagram showing an example (6) of installing a RIS on a mobility device according to an embodiment of the present invention. As shown in FIG. 17, a RIS may be installed on the mobility device and on stationary objects such as signs or buildings to increase the number of reflected paths. As shown in FIG. 17, a RIS may be selected to minimize the Doppler shift by emitting radio waves more perpendicular to the direction of movement, and the radio waves may be reflected or transmitted to radiate to the target terminal 20.

[0098] FIG. 17 shows an example of the operation on a highway, and for example, the following operations 1) to 6) may be executed.

[0099] 1) The terminal and RIS may periodically notify the base station of the location information of the terminal and RIS, or the vehicle, or the base station may estimate the location information. 2) The base station estimates the moving speed of the vehicle, i.e., the moving speed of the terminal or RIS, from the location information. The base station may also estimate the moving direction of the vehicle from the location information. 3) When transmitting radio waves from the base station (t０ ), it is assumed that there is no direct path to the target terminal. 4) The base station selects the RIS that minimizes the sum of the relative speed between the base station and the RIS and the relative speed between the RIS and the target terminal. The relative speed may be calculated from the vehicle's moving speed and direction. 5) The base station may select multiple RISs. For example, multiple RISs may be selected in descending order of the sum of the relative speed between the base station and the RIS and the relative speed between the RIS and the target terminal. 6) The selected RIS reflects and / or transmits the radio waves transmitted from the base station to the target terminal. The base station may instruct the RIS to perform this operation.

[0100] Also, as shown in FIG. 17, a mobility that minimizes the path to the target terminal and a RIS installed on a stationary object such as a sign or building may be selected to minimize power loss and delay.

[0101] 1) The terminal and the RIS may periodically notify the base station of the location information of the terminal and the RIS, or the vehicle, or the base station may estimate the location information. 2) When the base station transmits radio waves (t ０ ), it is assumed that there is no direct path to the target terminal. 3) From the location information, the base station selects the RIS that minimizes the sum of the distances between the base station and the RIS and between the RIS and the target. The base station may select multiple RISs. For example, multiple RISs may be selected in descending order of the sum. 4) The selected RIS reflects and / or transmits the radio waves transmitted from the base station to the target terminal. The base station may instruct the RIS to perform this operation.

[0102] Fig. 18 is a diagram showing an example (1) of installing a RIS on a stationary object in an embodiment of the present invention. As shown in Fig. 18, radio waves from a base station may be reflected to the upper floors of a building by a metasurface or a RIS. The metasurface or the RIS may be replaced with another relay device. For example, possible installation locations for the metasurface or the RIS may be the side wall of a building, a window glass, a rooftop floor, a signboard, a digital signage, the ground, etc. For example, as shown in Fig. 18, when the altitude h of the base station is Ｂ , RIS altitude hＲ , the altitude of the device h Ｕ In Ｒ <h Ｂ <h Ｕ That is, the installation situation may be one in which the altitude of the terminal is the highest and the altitude of the RIS is the lowest.

[0103] The placement location of the metasurface or RIS may be determined as follows:

[0104] 1) Create an optimization function related to user requirements from location information (base station and terminal) and the angle of incidence and / or angle of reflection of the metasurface or RIS at candidate installation locations for the metasurface or RIS. 2) Set constraints such as whether the metasurface or RIS can be installed and the threshold value of the user requirements, solve the optimization function, and determine the installation location.

[0105] The user requirements may be, for example, data rate, latency, quality, cost, power consumption, experience, and the like.

[0106] Fig. 19 is a flowchart for explaining an example of controlling a RIS in an embodiment of the present invention. Fig. 19 shows a method for determining a RIS to be controlled when a RIS capable of dynamically controlling the reflection direction is used in Fig. 18.

[0107] In step S101, the base station periodically acquires terminal location information or estimates the terminal location. In step S102, the base station groups RISs located between the base station and the terminal based on the terminal location information. Note that the location information of the base station and the RISs may be known. In FIG. 18, the RISs are grouped into group A and group B, and an example is shown in which group A is selected.

[0108] In step S103, the base station selects an uncontrolled RIS from the selected group. Note that the base station may estimate the received power in the desired area from the base station's transmission power based on the effective area of ​​the RIS, the incident angle and / or reflection angle of the RIS, distance attenuation, etc., calculated from the location information of the base station, the RIS, and the UE, and select the RIS that provides the highest received power to the terminal.

[0109] In step S104, the base station estimates the communication quality of terminal #n when using all RIS #n selected so far, based on the base station-RIS-terminal location information, etc. In step S105, the base station determines whether the estimated communication quality exceeds a threshold. If it exceeds the threshold (YES in S105), the flow ends, and if it does not exceed the threshold (NO in S105), the base station proceeds to step S103 and increases the number of selected RISs.

[0110] According to the above-described embodiment, the radio relay device 30 is installed on a moving or stationary object, and the direction of radio wave propagation is controlled, thereby improving the reception quality of the terminal.

[0111] That is, in a wireless communication system, the quality of communication can be improved by using a wireless relay device.

[0112] (Hardware Configuration) The block diagrams (FIGS. 2, 3, and 4) 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 for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0113] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As described above, the implementation method of each is not particularly limited.

[0114] For example, the base station 10, the terminal 20, the wireless relay device 30, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 20 is a diagram illustrating an example of the hardware configuration of the base station 10, the terminal 20, and the wireless relay device 30 according to an embodiment of the present disclosure. The base station 10, the terminal 20, and the wireless relay device 30 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, etc.

[0115] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configurations of the base station 10, the terminal 20, and the wireless relay device 30 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0116] Each function in the base station 10, terminal 20 and wireless relay device 30 is realized by loading specified software (programs) onto hardware such as a processor 1001, a memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0117] 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 140, control unit 240, etc. may be realized by the processor 1001.

[0118] Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002 and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the base station 10 shown in FIG. 2 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 3 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may also be transmitted from a network via a telecommunications line.

[0119] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), a RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0120] The secondary 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 appropriate medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0121] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0122] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0123] Furthermore, 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.

[0124] Furthermore, the base station 10, the terminal 20, and the wireless relay device 30 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), or a field programmable gate array (FPGA), 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.

[0125] Furthermore, the wireless relay device 30 may include, as necessary, a variable phase shifter, a phase shifter, an amplifier, an antenna, an array antenna, etc. as hardware that constitutes the variable section 340 and the antenna section 350.

[0126] Fig. 21 shows an example configuration of a vehicle 2001. As shown in Fig. 21, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0127] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0128] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0129] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0130] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing various types of information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 provides various types of multimedia information and multimedia services to the occupants of the vehicle 2001 by using information acquired from external devices via the communication module 2013, etc.

[0131] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0132] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0133] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0134] The communication module 2013 transmits, via wireless communication to an external device, a current signal from the current sensor that is input to the electronic control unit 2010. The communication module 2013 also transmits, via wireless communication to an external device, the rotation speed signals of the front and rear wheels acquired by a rotation speed sensor 2022, the air pressure signals of the front and rear wheels acquired by an air pressure sensor 2023, the vehicle speed signal acquired by a vehicle speed sensor 2024, the acceleration signal acquired by an acceleration sensor 2025, the accelerator pedal depression amount signal acquired by an accelerator pedal sensor 2029, the brake pedal depression amount signal acquired by a brake pedal sensor 2026, the shift lever operation signal acquired by a shift lever sensor 2027, and detection signals for detecting obstacles, vehicles, pedestrians, etc. acquired by an object detection sensor 2028, all of which are input to the electronic control unit 2010.

[0135] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on the information service unit 2012 provided in the vehicle 2001. The communication module 2013 also stores the various information received from the external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0136] (Summary of the embodiment) As described above, according to the embodiment of the present invention, a base station is provided which has an acquisition unit that acquires location information of a terminal and a plurality of wireless relay devices, a control unit that selects a wireless relay device to be controlled among the plurality of wireless relay devices based on the location information, and a transmission unit that transmits radio waves to the selected wireless relay device.

[0137] With the above configuration, the radio relay device 30 can be installed on a moving or stationary object and the direction of radio wave propagation can be controlled to improve the reception quality of the terminal. In other words, the communication quality can be improved by using the radio relay device in a wireless communication system.

[0138] The control unit may estimate a first relative velocity between the wireless relay device itself and a first wireless relay device included in the plurality of wireless relay devices and a second relative velocity between the first wireless relay device and the terminal based on the location information, and select a wireless relay device to be controlled among the plurality of wireless relay devices that minimizes the sum of the first relative velocity and the second relative velocity. With this configuration, the wireless relay device 30 is installed on a moving object or a stationary object, and the reception quality of the terminal can be improved by controlling the direction of radio wave propagation.

[0139] The control unit may estimate a first distance between the wireless relay device itself and the first wireless relay device and a second distance between the first wireless relay device and the terminal based on the location information, and select a wireless relay device to be controlled from among the plurality of wireless relay devices, which has a smallest sum of the first distance and the second distance. With this configuration, the wireless relay device 30 is installed on a moving object or a stationary object, and the reception quality of the terminal can be improved by controlling the direction of radio wave propagation.

[0140] The plurality of wireless relay devices may be installed on different mobile objects, respectively. With this configuration, the wireless relay devices 30 are installed on the mobile objects or stationary objects, and the direction of radio wave propagation can be controlled to improve the reception quality of the terminals.

[0141] The control unit may group the plurality of wireless relay devices based on the location information of the terminal, select one of the groups, and increase the number of wireless relay devices to be controlled included in the selected group until the estimated communication quality of the terminal exceeds a threshold. With this configuration, the wireless relay device 30 is installed on a moving object or a stationary object, and the reception quality of the terminal can be improved by controlling the direction of radio wave propagation.

[0142] Furthermore, according to an embodiment of the present invention, a communication method is provided in which a base station executes the steps of: acquiring location information of a terminal and a plurality of wireless relay devices; selecting a wireless relay device to be controlled from among the plurality of wireless relay devices based on the location information; and transmitting radio waves to the selected wireless relay device.

[0143] With the above configuration, the radio relay device 30 can be installed on a moving or stationary object and the direction of radio wave propagation can be controlled to improve the reception quality of the terminal. In other words, the communication quality can be improved by using the radio relay device in a wireless communication system.

[0144] (Supplementary Notes on the Embodiments) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these 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 invention; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (as long as there is no contradiction). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0145] 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 thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0146] Each aspect / embodiment described in the present disclosure may be implemented using any of the following standards: LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal number)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), 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 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802.34 ( The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of LTE and / or LTE-A with 5G).

[0147] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be rearranged unless it is consistent. 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.

[0148] In this specification, a specific operation described as being performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0149] The information, signals, etc. 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.

[0150] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be transmitted to another device.

[0151] In the present disclosure, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0152] 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.

[0153] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0154] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, 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.

[0155] Note that terms described in this disclosure and 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). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0156] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0157] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0158] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions 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 intended to be limiting in any way.

[0159] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0160] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned 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 terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage.

[0161] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0162] 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.

[0163] At least one of the base station and the mobile station may be referred to as 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 mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile 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 also include devices that do not necessarily move during communication operations. 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.

[0164] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments 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 multiple terminals 20 (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0165] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0166] 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, searching, inquiring (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 memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0167] 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 one or more wires, cables, and / or 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.

[0168] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0169] 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."

[0170] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. 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 in some way precede the second element.

[0171] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0172] 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." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0173] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called 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.

[0174] Numerology may be communication parameters that apply 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, specific filtering operations performed by the transceiver in the frequency domain, specific windowing operations performed by the transceiver in the time domain, etc.

[0175] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0176] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist 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.

[0177] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0178] 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 existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0179] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0180] 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) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0181] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0182] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0183] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 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 greater than or equal to 1 ms.

[0184] 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.

[0185] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0186] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0187] 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.

[0188] 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 given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0189] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be set for the terminal 20 within one carrier.

[0190] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," and the like in this disclosure may be read as "BWP."

[0191] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples, and various changes may be made to 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.

[0192] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0193] 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."

[0194] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0195] In the present disclosure, the variable section 340 and the antenna section 350 are an example of a relay section.

[0196] 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 herein. 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.

[0197] 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 30 Wireless relay device 310 Transmitter 320 Receiver 330 Control unit 340 Variable unit 350 Antenna unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheels 2008 Rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Revolution speed sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port (IO port)

Claims

1. A base station comprising: an acquisition unit that acquires position information of a terminal and a plurality of wireless relay devices respectively; a control unit that selects a wireless relay device to be controlled included in the plurality of wireless relay devices based on the position information; and a transmission unit that transmits radio waves to the selected wireless relay device.

2. The base station according to claim 1, wherein the control unit estimates a first relative speed between the self-device and a first wireless relay device included in the plurality of wireless relay devices and a second relative speed between the first wireless relay device and the terminal based on the position information, and selects a wireless relay device to be controlled included in the plurality of wireless relay devices such that the sum of the first relative speed and the second relative speed is minimized.

3. The base station according to claim 1, wherein the control unit estimates a first distance between the self-device and the first wireless relay device and a second distance between the first wireless relay device and the terminal based on the position information, and selects a wireless relay device to be controlled included in the plurality of wireless relay devices such that the sum of the first distance and the second distance is minimized.

4. The base station according to claim 1, wherein the plurality of wireless relay devices are respectively installed in a plurality of different moving bodies.

5. The base station according to claim 1, wherein the control unit groups the plurality of wireless relay devices based on the position information of the terminal, selects one of the groups, and increases the number of wireless relay devices to be controlled included in the selected group until the estimated communication quality at the terminal exceeds a threshold.

6. A communication method in which a base station executes a procedure of acquiring position information of a terminal and a plurality of wireless relay devices respectively, a procedure of selecting a wireless relay device to be controlled included in the plurality of wireless relay devices based on the position information, and a procedure of transmitting radio waves to the selected wireless relay device.

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