Relay device and communication system

Abstract

To start the communication from a communication terminal side when communication is to be started between a communication terminal and a base station via a relay device 2.SOLUTION: A relay device 2 relays communication between a base station and a communication terminal, and includes a control communication unit 21 that receives control data from the communication terminal indicating a beam ID for identifying a beam to be used when the relay device 2 and the base station communicate, a base station side communication unit 222 that communicates with the base station, and a control unit 24 that controls the base station side communication unit 222 such that the base station side communication unit 222 communicates with the base station using a beam corresponding to the beam ID.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] It has been proposed that a relay device relays communication between a base station and a user's communication terminal. For example, Patent Document 1 describes that a base station transmits downlink data to a communication terminal via a relay device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-36366 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, a base station instructs a relay device on a beam pattern to be used by the relay device for communication between the relay device and a communication terminal. However, the technology described in Patent Document 1 has a problem in that the communication terminal cannot instruct the relay device on a beam pattern to be used by the relay device. Therefore, when starting communication between a communication terminal and a base station via a relay device, the communication terminal cannot start the communication from its side.

[0005] Therefore, the present invention has been made in consideration of these points, and aims to provide a relay device that can initiate communication from the communication terminal side when communication is initiated between a communication terminal and a base station via the relay device. [Means for solving the problem]

[0006] A first aspect of the relay device of the present invention is a relay device that relays communication between a base station and a communication terminal, and includes a control communication unit that receives control data from the communication terminal indicating a beam ID for identifying a beam to be used when the relay device and the base station communicate, a base station side communication unit that communicates with the base station, and a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID.

[0007] The control data may include a plurality of beam IDs corresponding to a plurality of beams, and the control unit may control the base station side communication unit to transmit any one of the plurality of beams corresponding to the plurality of beam IDs. The control data may include timing information indicating a timing to transmit a beam, and the control unit may control the base station side communication unit to transmit a beam at a timing indicated by the timing information.

[0008] The control data associates a relay device ID for identifying each of the multiple relay devices with a beam ID used when the relay device communicates with the base station, and when the control data includes a relay device ID stored in the relay device, the control unit may control the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID.

[0009] The control data associates a relay device ID for identifying each of the multiple relay devices with timing information indicating the timing at which the relay device transmits a beam, and when the control data includes a relay device ID stored in the relay device, the control unit may control the base station side communication unit so that the base station side communication unit communicates with the base station at the timing indicated by the timing information.

[0010] The control data may include information indicating a period for transmitting a beam from the relay device to the base station, and the control unit may control the base station side communication unit to form a beam corresponding to the beam ID indicated by the control data at the period indicated by the control data. The control communication unit may receive the control data via a control link for communicating directly with the communication terminal without going through another device.

[0011] A second aspect of the present invention provides a communication system comprising a communication terminal and a relay device that relays communication between a base station and the communication terminal, wherein the communication terminal has a determination unit that determines a beam ID for identifying a beam to be used when the relay device and the base station communicate, and a transmission unit that transmits control data indicating the beam ID determined by the determination unit, and the relay device has a control communication unit that receives control data from the communication terminal that indicates a beam ID for identifying a beam to be used when the relay device and the base station communicate, a base station side communication unit that communicates with the base station, and a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID.

[0012] The determination unit may select the beam ID corresponding to a beam that provides a relatively high quality signal received by the base station while the relay device communicates with the base station using different beams. [Effects of the Invention]

[0013] According to the present invention, when communication is initiated between a communication terminal and a base station via a relay device, the communication is initiated from the communication terminal side. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an overview of a communication system. [Figure 2] FIG. 1 is a diagram illustrating an overview of a communication system. [Figure 3] 1 shows the configuration of a communication terminal. [Figure 4] 10 shows an example of control data for a relay device to communicate over an access link. [Figure 5] 1 shows the configuration of a relay device. [Figure 6] An example of timing at which the control unit forms a beam by using the data communication unit will be shown. [Figure 7] 10 shows another example of timing at which the control unit forms a beam using the data communication unit. [Figure 8] 10 shows another example of control data transmitted by the communication control unit. [Figure 9] FIG. 10 is a sequence diagram showing a processing procedure for starting data communication by the communication system. DETAILED DESCRIPTION OF THE INVENTION

[0015] [Communication System S Overview] 1 and 2 are diagrams for explaining an overview of a communication system S. The communication system S includes a communication terminal 1, a relay device 2, and a base station 3. The communication system S enables the communication terminal 1 to connect to the base station 3 via the relay device 2.

[0016] The communication terminal 1 is, for example, a smartphone. The communication terminal 1 communicates with the base station 3 via the relay device 2. The communication terminal 1 selects one of a plurality of beam patterns (the dashed ellipse of the communication terminal 1 in FIG. 1) that indicate the directionality of the transmission and reception of electromagnetic waves. The communication terminal 1 communicates with the relay device 2 by forming a beam of the selected beam pattern.

[0017] The relay device 2 has an RF (Radio Frequency) relay function. The relay device 2 relays communication between the base station 3 and the communication terminal 1. The relay device 2 has a control communication unit 21 and a data communication unit 22.

[0018] The control communication unit 21 receives control data from the communication terminal 1. The control data includes, for example, a beam ID for identifying a beam used when the relay device 2 and the base station 3 communicate with each other. As an example, the control data is in an SCI (Side Control Information) format. The control communication unit 21 communicates with the communication terminal 1 by directional communication, but may also communicate with the communication terminal 1 by non-directional communication. The control communication unit 21 communicates with the communication terminal 1 over a relatively short distance of approximately a maximum of several meters.

[0019] The data communication unit 22 communicates with the communication terminal 1 and the base station 3. The data communication unit 22 transmits and receives data such as audio or video between the communication terminal 1 and the base station 3. The data communication unit 22 communicates with the communication terminal 1 or the base station 3 by forming a beam corresponding to a beam ID included in the control data received by the control communication unit 21. The beam ID is identification information for identifying a beam pattern.

[0020] [Processing Procedure for Communication Terminal 1 to Start Communication with Base Station 3 via Relay Device 2] 1(a), 1(b), 2(a) and 2(b), a process procedure in which communication terminal 1 starts communication with base station 3 via relay device 2 will be described below. Communication terminal 1 establishes a D2D (Device to Device) connection with control communication unit 21 of relay device 2. At this time, communication terminal 1 transmits a measurement target signal to relay device 2 by sequentially switching among a plurality of beam patterns (dashed ovals of communication terminal 1 in FIG. 1(a)) that can be used for beam formation, as indicated by the double-headed arrows of communication terminal 1 in FIG. 1(a).

[0021] As indicated by the double-headed arrow of the control communication unit 21 in FIG. 1(a), the control communication unit 21 receives the signal to be measured by sequentially switching among a plurality of beam patterns (dashed ovals of the control communication unit 21 in FIG. 1(a)) that can be formed into beams. The control communication unit 21 measures the communication quality of the signal received using each beam pattern. The control communication unit 21 notifies the communication terminal 1 of the measurement result of the beam pattern of the communication terminal 1 with the best measured communication quality. The communication terminal 1 determines the beam pattern of the communication terminal 1 with the best measured communication quality as the beam pattern for control link communication.

[0022] The control communication unit 21 determines the beam pattern of the control communication unit 21 with the best measured communication quality as the beam pattern for control link communication. The communication terminal 1 and the relay device 2 establish a control link using the beam patterns they have determined. In FIG. 1(b), the beam patterns determined by the communication terminal 1 and the control communication unit 21 as the beam pattern for control link communication are hatched.

[0023] Next, the communication terminal 1 establishes a backhaul link for transmitting and receiving audio or video between the communication terminal 1 and the data communication unit 22 of the relay device 2. For example, the communication terminal 1 uses the same beam pattern for the backhaul link as for the control link. The data communication unit 22 uses the same beam pattern for the backhaul link as for the control link. In FIG. 2(a), the beam patterns determined by the communication terminal 1 and the data communication unit 22 as the beam patterns for communication on the backhaul link are each hatched.

[0024] The communication terminal 1 establishes an access link for transmitting and receiving audio or video between the data communication unit 22 and the base station 3. In the examples of Fig. 2(a) and Fig. 2(b), the communication terminal 1 transmits control data via the control link instructing the data communication unit 22 to form a beam of one of a plurality of beam patterns that can be formed in communication with the base station 3.

[0025] The data communication unit 22 transmits a measurement target signal to the base station 3 by forming a beam of a specified beam pattern from among a plurality of beam patterns, as indicated by the double arrow on the right side of the data communication unit 22 in FIG. 2(a). The base station 3 receives the measurement target signal by forming a beam of one of a plurality of beam patterns that can be formed, as indicated by the double arrow on the base station 3 in FIG. 2(a). The base station 3 measures the communication quality of the data transmitted using each beam pattern. The data communication unit 22 transmits the measurement target signal using each of the plurality of beam patterns, and the base station 3 notifies the communication terminal 1 via the relay device 2 of the beam pattern with the best measured communication quality from among the plurality of beam patterns transmitted by the data communication unit 22.

[0026] The communication terminal 1 determines the notified beam pattern as the beam pattern of the relay device 2 for communication over the access link. The base station 3 determines the beam pattern of the base station 3 with the best measured communication quality as the beam pattern of the base station 3 for communication over the access link. In Fig. 2(b), the determined beam pattern of the relay device 2 on the base station 3 side and the determined beam pattern of the base station 3 are hatched.

[0027] In this way, in the communication system S, when communication is initiated between the communication terminal 1 and the base station 3 via the relay device 2, the communication terminal 1 instructs the beam pattern of the beam formed by the relay device 2, so that communication can be initiated from the communication terminal 1 side.

[0028] [Configuration of communication terminal 1] 3 shows the configuration of the communication terminal 1. The communication terminal 1 includes a communication unit 11, a storage unit 12, and a control unit 13. The communication unit 11 connects to a network by communicating with a base station 3 via a relay device 2. The communication unit 11 communicates with the relay device 2 by forming a beam of one of a plurality of beam patterns that can be formed.

[0029] The storage unit 12 has storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an SSD (Solid State Drive). The storage unit 12 stores a program executed by the control unit 13. The storage unit 12 stores a beam ID and a beam pattern in association with each other. The control unit 13 has, for example, a CPU (Central Processing Unit), and functions as a determination unit 131 and a communication control unit 132 by executing the program stored in the storage unit 12.

[0030] The determination unit 131 determines a beam pattern to be formed by the communication unit 11 or the relay device 2. The determination unit 131 selects a beam ID corresponding to a beam that provides a relatively high quality signal received by the base station 3 while the relay device 2 communicates with the base station 3 using different beams.

[0031] More specifically, when determining a beam pattern to be communicated via the control link, the determination unit 131 sequentially switches between a plurality of beam patterns that the communication unit 11 can form while transmitting a measurement target signal for measuring communication quality to the relay device 2. The determination unit 131 receives, via the communication unit 11, a measurement result obtained by the relay device 2 measuring the beam pattern with the best communication quality of the transmitted measurement target signal. The determination unit 131 determines the beam pattern with the best measured communication quality as the beam pattern for communication on the control link.

[0032] The determination unit 131 determines a beam pattern for communication via a backhaul link that transmits and receives data such as audio or video to and from the relay device 2. The backhaul link may have the same frequency as the control link, or may have a different frequency. For example, the determination unit 131 determines the same beam pattern as the control link as the beam pattern for communication on the backhaul link. The determination unit 131 determines beam IDs corresponding to the beam patterns determined as the beam patterns for communication on the control link and the backhaul link, respectively.

[0033] The determination unit 131 determines the beam ID of the beam pattern of the beam to be used when the relay device 2 and the base station 3 communicate with each other. For example, the determination unit 131 determines the beam ID of the beam pattern for transmitting and receiving data such as video or audio between the relay device 2 and the base station 3 via an access link. The access link may be the same frequency as the control link or the backhaul link, or may be a different frequency. In order to determine the beam pattern to be used by the relay device 2 and the base station 3, the determination unit 131 sequentially transmits control data via the control link instructing the data communication unit 22 to form a beam of one of a plurality of beam patterns that can be formed by the data communication unit 22.

[0034] After the data communication unit 22 of the relay device 2 sequentially transmits the measurement target signal to the base station 3 by forming beams of the beam pattern instructed by the determination unit 131, the determination unit 131 receives from the base station 3 via the communication unit 11 the measurement results of the communication quality of the data transmitted by the base station 3 measured by the base station 3. The measurement results indicate, for example, the beam pattern of the relay device 2 with the best communication quality. The determination unit 131 determines the beam pattern of the relay device 2 with the best communication quality as the beam pattern of the relay device 2 for communication of the access link.

[0035] The communication control unit 132 communicates with the relay device 2 via the communication unit 11. The communication control unit 132 transmits control data including a beam ID of the beam pattern determined by the determination unit 131 to the relay device 2. For example, the communication control unit 132 transmits the control data to the relay device 2 via a sidelink physical control channel. The control data may include multiple beam IDs corresponding to multiple beams. In addition to the beam ID, the control data may also include timing information indicating the timing of transmitting the beam. The timing information indicates, for example, slot timing that identifies a slot that accommodates the beam. In addition to the beam ID, the control data may also include period information indicating the period of transmitting the beam from the relay device 2 to the base station 3. The control data may also include an SCI (Side Control Information) format ID. The SCI format ID is identification information for identifying the format of the SCI.

[0036] Fig. 4 shows an example of control data for the relay device 2 to communicate over the access link. In the example of Fig. 4, the control data includes items of beam ID and slot timing. The beam ID is identification information for identifying a beam pattern. The slot timing is an ID for identifying a slot.

[0037] In the example on the left side of Figure 4, beam ID "#X" is associated with slot timing "2." This example shows that a beam with beam ID "#X" is formed at a timing corresponding to the second slot from the beginning of each data transmission period. In the example on the right side of Figure 4, beam ID "#Y" is associated with slot timing "3." This example shows that a beam with beam ID "#Y" is formed at a timing corresponding to the third slot from the beginning of each data transmission period.

[0038] [Configuration of Relay Device 2] 5 shows the configuration of the relay device 2. The relay device 2 includes a control communication unit 21, a data communication unit 22, a storage unit 23, and a control unit 24. The data communication unit 22 includes a terminal-side communication unit 221 and a base station-side communication unit 222.

[0039] The control communication unit 21 receives control data from the communication terminal 1 that instructs the beam pattern to be used when the relay device 2 communicates with the communication terminal 1 or the base station 3. The control communication unit 21 receives the control data via a control link for communicating directly with the communication terminal 1 without going through another device. For example, this control link is a control link established by a direct communication function of D2D (Device To Device).

[0040] The terminal-side communication unit 221 communicates with the communication terminal 1 via a backhaul link. The terminal-side communication unit 221 receives data such as audio or video from the communication terminal 1 and transmits data such as audio or video to the communication terminal 1.

[0041] The base station side communication unit 222 communicates with the base station 3. The base station side communication unit 222 communicates with the base station 3 via an access link. The base station side communication unit 222 receives data such as audio or video from the base station 3 and transmits data such as audio or video to the base station 3.

[0042] The storage unit 23 has storage media such as a ROM, a RAM, and an SSD. The storage unit 23 stores programs to be executed by the control unit 24. The control unit 24 has, for example, a CPU, and executes the programs stored in the storage unit 23 to perform various functions.

[0043] The control unit 24 receives control data from the communication terminal 1 via the control communication unit 21. The control unit 24 transmits and receives data such as audio or video to and from the communication terminal 1 via the terminal-side communication unit 221. The control unit 24 transmits and receives data such as audio or video to and from the base station 3 via the base station-side communication unit 222.

[0044] [Beam Forming] The control unit 24 controls the base station side communication unit 222 so that the base station side communication unit 222 communicates with the base station 3 using a beam corresponding to the beam ID included in the received control data. When the control data includes multiple beam IDs corresponding to multiple beams, the control unit 24 controls the base station side communication unit 222 so that one or more of the multiple beams corresponding to the multiple beam IDs are formed.

[0045] When the control data includes timing information indicating the timing of transmitting a beam, the control unit 24 controls the base station-side communication unit 222 to form a beam at the timing indicated by this timing information. When the control data includes period information indicating the period for transmitting a beam from the relay device 2 to the base station 3, the control unit 24 controls the base station-side communication unit 222 to transmit a beam corresponding to the beam ID indicated by the control data at the period indicated by the control data. When the control unit 24 receives control data related to communication between the terminal-side communication unit 221 and communication terminal 1, the control unit 24 controls the terminal-side communication unit 221 in the same manner as it controls the base station-side communication unit 222.

[0046] Figure 6 shows an example of the timing at which the control unit 24 forms a beam using the data communication unit 22. The horizontal axis in Figure 6 indicates the transmission time of data such as audio or video. As shown in the upper part of Figure 6, the control unit 24 forms a beam with beam ID "#X" and a beam with beam ID "#Y" at different timings. The control unit 24 forms a beam with beam ID "#X" or a beam with beam ID "#Y" for each slot into which the data transmission time is divided. In Figure 6, the times at which the control unit 24 forms a beam with beam ID "#X" are hatched.

[0047] As shown in the lower part of Figure 6, the slot offset (#X) indicates the time from the start of the period to the start of the slot containing the beam with beam ID "#X". The symbol offset (#X) indicates the time from the start of the slot containing the beam with beam ID "#X" to the start of beam formation with beam ID "#X". The duration (#X) indicates the time from the start of beam formation with beam ID "#X" to the end of beam formation with beam ID "#X".

[0048] The control unit 24 forms beams with beam ID "#X" and beam ID "#Y" at the period indicated by the period information included in the control data received by the control communication unit 21. The control unit 24 forms a beam with beam ID "#X" at the timing to be accommodated in the slot indicated by the slot timing associated with beam ID "#X" included in the control data received by the control communication unit 21. The control unit 24 forms a beam with beam ID "#Y" at the timing to be accommodated in the slot indicated by the slot timing associated with beam ID "#Y" included in the control data received by the control communication unit 21.

[0049] When the control data received by the control communication unit 21 includes a slot offset, a symbol offset, or a duration, the control unit 24 may form a beam at the timing indicated by the slot offset, the symbol offset, or the duration. For example, when the control data received by the control communication unit 21 includes a beam ID "#X" associated with a symbol offset of "0.1 milliseconds," the control unit 24 may start forming a beam with the beam ID "#X" 0.1 milliseconds after the start timing of the slot.

[0050] In Figure 6, an example was described in which the control unit 24 forms a beam with beam ID "#X" and a beam with beam ID "#X" in the same order in multiple periods included in the data transmission time. However, the control unit 24 may form a beam with beam ID "#X" and a beam with beam ID "#Y" in different orders in multiple periods included in the data transmission time. Figure 7 shows another example of the timing at which the control unit 24 forms beams using the data communication unit 22. In the example of Figure 7, the positions of the slots accommodating the beams with beam ID "#X" and beam ID "#Y" differ for each period. Therefore, the control unit 24 forms a beam with beam ID "#X" and a beam with beam ID "#Y" in different orders for each period.

[0051] <Modification with Multiple Relay Devices 2> The communication system S may include a plurality of relay devices 2. The communication control unit 132 of the communication terminal 1 may transmit common control data to each of the plurality of relay devices 2, which associates a relay device ID for identifying each of the plurality of relay devices 2, a beam ID used when the relay device 2 communicates with the base station 3, and timing information indicating the timing at which the relay device 2 transmits a beam. The control data does not have to include either the beam ID or the timing information.

[0052] 8 shows another example of control data transmitted by the communication control unit 132. The control data includes items for a relay device ID, a beam ID, and a slot timing indicating the timing at which the relay device 2 transmits a beam. In the example at the top of FIG. 8, the control data instructs the relay device 2 with relay device ID "#A" to form a beam with beam ID "#X, #Y, or #Z" in the slot indicated by slot timing "3" in communication with the base station 3 via the access link. In the example at the bottom of FIG. 8, the control data instructs the relay device 2 with relay device ID "#B" to form a beam with beam ID "#X or #Z" in the slot indicated by slot timing "4" in communication with the base station 3 via the access link.

[0053] The following describes a method by which the determination unit 131 determines in advance the relay device 2 that will relay communication. The determination unit 131 transmits a measurement target signal for measuring communication quality to the base station 3 via the relay device 2 with relay device ID "#A." Next, the determination unit 131 transmits the measurement target signal to the base station 3 via the relay device 2 with relay device ID "#B." The base station 3 measures the communication quality of each of the received measurement target signals. The base station 3 notifies the determination unit 131 of the measurement result of the relay device 2 with the best communication quality. The determination unit 131 determines the notified relay device 2 as the relay device 2 that will relay communication. The communication control unit 132 transmits common control data including the relay device ID of the relay device 2 determined by the determination unit 131 to each relay device 2. The determination unit 131 repeats the process of determining the relay device 2 that will relay communication at predetermined intervals. The predetermined time is, for example, several minutes.

[0054] When the control data received by the control communication unit 21 includes the relay device ID of the relay device 2 stored in the relay device 2, the control unit 24 controls the base station side communication unit 222 so that the base station side communication unit 222 communicates with the base station 3 using a beam corresponding to the beam ID associated with this relay device ID. When the control data received by the control communication unit 21 includes the relay device ID of the relay device 2 stored in the relay device 2, the control unit 24 controls the base station side communication unit 222 so that the base station side communication unit 222 communicates with the base station 3 at the timing indicated by the timing information associated with this relay device ID.

[0055] For example, when a relay device 2 with a relay device ID "#A" receives the control data shown in Fig. 8, it forms a beam with a beam ID "#X, #Y, or #Z" associated with its own relay device ID "#A." At this time, this relay device 2 forms this beam at a timing that is accommodated in the slot indicated by the slot timing "3" associated with its own relay device ID "#A."

[0056] [Processing procedure for starting data communication by communication system S] 9 is a sequence diagram showing the processing procedure for starting data communication by the communication system S. This processing procedure starts, for example, when the power switch of the communication terminal 1 is turned on. First, the communication control unit 132 of the communication terminal 1 synchronizes with the control communication unit 21 of the relay device 2 by repeatedly transmitting a synchronization signal to the control communication unit 21. The communication control unit 132 sequentially switches between a plurality of beam patterns that can be used to form a beam, and transmits the measurement target signal to the control communication unit 21 by forming a beam of each beam pattern. The control communication unit 21 sequentially switches between a plurality of beam patterns that can be used to form a beam, and receives the measurement target signal by forming a beam of each beam pattern, and measures the communication quality of the measurement target signal.

[0057] The control communication unit 21 identifies the combination of beam patterns with the best measured communication quality. The control communication unit 21 determines the beam pattern of the control communication unit 21 with the best measured communication quality as the beam pattern of the control communication unit 21 for control link communication. The control communication unit 21 notifies the communication control unit 132 of the measurement result of the beam pattern of the communication control unit 132 with the best measured communication quality. The determination unit 131 determines the notified beam pattern of the communication control unit 132 as the beam pattern for control link communication (S101). The control communication unit 21 and the communication control unit 132 establish a control link for communication between the control communication unit 21 and the communication control unit 132.

[0058] The communication control unit 132 and the data communication unit 22 establish a backhaul link for transmitting and receiving data such as audio or video using a combination of beam patterns with the best measured communication quality. To establish the backhaul link, the communication control unit 132 sequentially transmits, via the control link, control data instructing the data communication unit 22 to select one of a plurality of beam patterns that can be used to form a beam in communication with the base station 3.

[0059] The data communication unit 22 sequentially transmits the measurement target signal to the base station 3 by forming a beam of a beam pattern indicated by the control data received by the control communication unit 21 from among a plurality of beam patterns that can be formed. The base station 3 sequentially switches between the plurality of beam patterns that can be formed, receives the measurement target signal by forming a beam of each beam pattern, and measures the communication quality of the measurement target signal. The base station 3 identifies the combination of beam patterns that provides the best measured communication quality.

[0060] The base station 3 determines the beam pattern of the base station 3 with the best measured communication quality as the beam pattern for communication over the access link. The base station 3 notifies the data communication unit 22 of the measurement result of the beam pattern of the data communication unit 22 with the best measured communication quality. The data communication unit 22 determines the notified beam pattern of the data communication unit 22 as the beam pattern for communication over the access link, and establishes the access link. The communication control unit 132 performs data communication with the base station 3 over the established access link.

[0061] [Effects of Communication System S] As described above, in the communication system S according to this embodiment, when communication is initiated between the communication terminal 1 and the base station 3 via the relay device 2, the communication control unit 132 of the communication terminal 1 instructs the beam pattern of the beam formed by the data communication unit 22 of the relay device 2, so that this communication can be initiated from the communication terminal 1 side.

[0062] Furthermore, this invention will make it possible to contribute to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is "Build resilient infrastructure, promote inclusive and sustainable industrialization, and promote innovation and resilience."

[0063] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0064] 1. Communication terminal 2. Relay device 3 base station 11 Communications Department 12 Storage section 13 Control Unit 21 Control and communication unit 22 Data Communications Department 23 Memory section 24 Control Unit 131 Decision Section 132 Communication control section 221 Terminal communication unit 222 Base station communication unit

Claims

1. A relay device that relays communication between a base station and a communication terminal, a control communication unit that receives, from the communication terminal, control data indicating a beam ID for identifying a beam used when the relay device and the base station communicate; a base station side communication unit that communicates with the base station; a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID; and In the control data, a relay device ID for identifying each of the plurality of relay devices is associated with a beam ID used when the relay device communicates with the base station, When the control data includes a relay device ID stored in the relay device, the control unit controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID. Relay device.

2. A relay device that relays communication between a base station and a communication terminal, a control communication unit that receives, from the communication terminal, control data indicating a beam ID for identifying a beam used when the relay device and the base station communicate; a base station side communication unit that communicates with the base station; a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID; and In the control data, a relay device ID for identifying each of the plurality of relay devices is associated with timing information indicating a timing at which the relay device transmits a beam, the control unit controls the base station side communication unit so that the base station side communication unit communicates with the base station at a timing indicated by the timing information when the control data includes a relay device ID stored in the relay device. Relay device.

3. the control data includes information indicating a period for transmitting a beam from the relay device to the base station, the control unit controls the base station side communication unit to form a beam corresponding to the beam ID indicated by the control data at a period indicated by the control data. The relay device according to claim 1 or 2.

4. the control communication unit receives the control data via a control link for communicating directly with the communication terminal without going through another device; The relay device according to claim 1 or 2.

5. a communication terminal; and a relay device that relays communication between a base station and the communication terminal; The communication terminal a determination unit that determines a beam ID for identifying a beam to be used when the relay device and the base station communicate with each other; a transmitter that transmits control data indicating the beam ID determined by the determiner; and The relay device a control communication unit that receives, from the communication terminal, control data indicating a beam ID for identifying a beam used when the relay device and the base station communicate; a base station side communication unit that communicates with the base station; a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID; and In the control data, a relay device ID for identifying each of the plurality of relay devices is associated with a beam ID used when the relay device communicates with the base station, When the control data includes a relay device ID stored in the relay device, the control unit controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID. Communication system.

6. a communication terminal; and a relay device that relays communication between a base station and the communication terminal; The communication terminal a determination unit that determines a beam ID for identifying a beam to be used when the relay device and the base station communicate with each other; a transmitter that transmits control data indicating the beam ID determined by the determiner; and The relay device a control communication unit that receives, from the communication terminal, control data indicating a beam ID for identifying a beam used when the relay device and the base station communicate; a base station side communication unit that communicates with the base station; a control unit that controls the base station side communication unit so that the base station side communication unit communicates with the base station using a beam corresponding to the beam ID; and In the control data, a relay device ID for identifying each of the plurality of relay devices is associated with timing information indicating a timing at which the relay device transmits a beam, the control unit controls the base station side communication unit so that the base station side communication unit communicates with the base station at a timing indicated by the timing information when the control data includes a relay device ID stored in the relay device. Communication system.

7. the determination unit selects the beam ID corresponding to a beam with a relatively high quality of a signal received by the base station while the relay device communicates with the base station using different beams.

7. A communication system according to claim 5 or 6.

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