JP7827076B2 - Wireless communication system, management device therefor, relay device, communication control method, and communication control program - Google Patents

Description

The present invention relates to a wireless communication system, a management device therefor, a relay device, a communication control method, and a communication control program.

In recent years, in the field of wireless communications, due to the increasing speed and capacity and the shortage of available frequency bands, there is a demand for the use of short-wavelength radio waves such as millimeter waves and terahertz waves.

However, radio waves have short wavelengths, so blind spots can occur when there are obstacles in the way. To eliminate blind spots, a conventional technology uses a reflector to reflect communication signals between base stations and mobile terminals (Patent Document 1). This technology measures and compares the received power of a mobile terminal when the reflector reflects radio waves in a first direction and when the reflector reflects radio waves in a second direction. The direction of the reflector with the highest reception strength is then determined.

Japanese Patent Application Laid-Open No. 2021-57723

However, conventional technology has the problem that it takes time to try switching the reflection direction. Furthermore, conventional technology has the problem that the reflection direction is limited because the position of the reflector is fixed. Furthermore, conventional technology has the problem that it is not possible to determine the appropriate reflection direction when the received power is close to zero and therefore cannot be measured.

Therefore, the object of the present invention is to provide a wireless communication system, a management device, a relay device, a communication control method, and a communication control program therefor, which are capable of transmitting a radio wave beam to a mobile terminal device even if the terminal device is in a radio wave blind spot.

The above object of the present invention is achieved by the following means.

(1) A wireless communication system comprising: a mobile terminal device; an antenna that transmits a radio wave beam including a communication signal to the terminal device; a relay device that relays the radio wave beam transmitted from the antenna to the terminal device; and a management device that acquires location information of at least one of the terminal device and the relay device and controls the antenna to transmit the radio wave beam toward the relay device based on the acquired location information, wherein the relay device is a reflector, and a plurality of the reflectors are arranged in an array, and the management device selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector .

(2) A wireless communication system as described in (1) above, in which the management device acquires location information of the terminal device and location information of the relay device, moves the relay device based on the location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device.

(3) The relay device is provided in plurality,
The wireless communication system described in (1) above, wherein the management device acquires location information of the terminal device, selects a relay device from among multiple relay devices to relay the radio wave beam based on the location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device.

(4) The relay device acquires location information of the terminal device, and is capable of moving to a position where it can transmit the radio beam to the terminal device based on the location information of the terminal device and the antenna,
The wireless communication system described in (1) above, wherein the management device acquires location information of the relay device and controls the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device.

( 5 ) The wireless communication system according to ( 1 ), wherein the management device changes the orientation of the reflector based on location information of the terminal device.

( 6 ) A management device that acquires location information of at least one of a mobile terminal device and a relay device that relays a radio wave beam transmitted from an antenna to the terminal device, and controls the antenna to transmit the radio wave beam toward the relay device based on the acquired location information, wherein the relay device is a reflector, and a plurality of the reflectors are arranged in an array, and the management device selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector.

( 7 ) A management device as described in (6) above, which acquires location information of the terminal device and location information of the relay device, moves the relay device based on the location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device.

( 8 ) The relay device is provided in plurality,
The management device described in (6) above selects a relay device to relay the radio wave beam from among a plurality of relay devices based on the acquired location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device.

( 9 ) The relay device acquires location information of the terminal device, and is capable of moving to a position where it can transmit the radio wave beam to the terminal device based on the location information of the terminal device and the antenna,
The management device according to ( 6 ) above, which acquires location information of the relay device, and controls the antenna to transmit the radio beam toward the relay device based on the location information of the relay device.

( 10 ) The management device according to ( 9 ) above, which changes the orientation of the reflector based on the position information of the terminal device.

( 11 ) A relay device that relays a radio wave beam transmitted from an antenna to a mobile terminal device, the relay device being a reflector, with multiple reflectors arranged in an array, acquiring location information of the terminal device, and based on the location information of the terminal device and the antenna, moving to a position where the radio wave beam can be transmitted to the terminal device, and transmitting the radio wave beam toward at least one reflector selected from the multiple reflectors .

( 12 ) The relay device according to ( 11 ) above, wherein the orientation of the reflector is changed based on the position information of the terminal device.

( 13 ) A step (a) of acquiring location information of at least one of a mobile terminal device and a relay device that relays a radio wave beam transmitted from an antenna to the terminal device;
and (b) controlling the antenna to transmit the radio wave beam toward the relay device based on the acquired location information ,
the relay device is a reflector, and a plurality of the reflectors are arranged in an array;
A communication control method , wherein step (b) selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector .

( 14 ) The relay device is provided in plurality,
The communication control method described in (13) above, wherein the step (b) selects a relay device for relaying the radio wave beam from among a plurality of relay devices based on the acquired location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device.

( 15 ) The relay device acquires location information of the terminal device, and is capable of moving to a position where it can transmit the radio wave beam to the terminal device based on the location information of the terminal device and the antenna,
The step (a) includes acquiring location information of the relay device;
The communication control method according to ( 13 ) above, wherein the step (b) controls the antenna to transmit the radio wave beam toward the relay device based on location information of the relay device.

( 16 ) The communication control method according to ( 13 ) above, wherein the step (b) changes the orientation of the reflector based on position information of the terminal device.

( 17 ) A communication control program for causing a computer to execute the communication control method according to any one of ( 13 ) to ( 16 ) above.

The present invention can change the direction of a radio wave beam to optimize the radio wave path based on the location information of at least one of a mobile terminal device and a relay device that relays the radio wave beam from the antenna. Therefore, according to the present invention, even if a mobile terminal device is in a radio wave blind spot, the radio wave beam can reach the terminal device.

1 is a schematic diagram for explaining a wireless communication system according to a first embodiment. 10 is a flowchart showing a procedure for implementing a communication control method by a radio wave management server. 1 is a schematic diagram for explaining an incident angle and a reflection angle on a reflector. FIG. FIG. 10 is a schematic diagram illustrating a wireless communication system according to a second embodiment. FIG. 10 is a schematic diagram for explaining a wireless communication system according to a third embodiment. FIG. 10 is a schematic diagram illustrating a wireless communication system according to a fourth embodiment.

Embodiments of the present invention will now be described in detail with reference to the drawings. Note that in the description of the drawings, identical elements will be given the same reference numerals, and duplicate explanations will be omitted. Also, the dimensional proportions in the drawings have been exaggerated for the sake of explanation, and may differ from the actual proportions.

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a wireless communication system according to a first embodiment.

As shown in Figure 1, the wireless communication system 1 according to the first embodiment includes a terminal device 100, an antenna 201, a reflector 202, and a radio wave management server 300. Connected to the antenna 201 are a radio unit (RU) and base station equipment that perform wireless communication with the terminal device 100, but these are not shown here.

The terminal device 100 is mobile. The terminal device 100 is capable of wireless communication with wireless units, base station equipment, etc. For this reason, the terminal device 100 has a wireless unit necessary for communication with wireless units, base station equipment, etc.

The terminal device 100 may be, for example, an automatic guided vehicle (AGV), a mobile robot, an aerial drone, or an underwater or surface drone. These terminal devices 100 may be autonomously moving devices or remotely controlled devices. Furthermore, the terminal device 100 may be a device that moves while being carried by a person, such as a smartphone or a tablet computer.

Antenna 201 transmits a beamformed radio wave beam. The radio wave beam includes a communication signal to terminal device 100. The radio wave beam is, for example, a radio wave with a short wavelength, such as a millimeter wave or a terahertz wave. Beamforming is a technology that forms a directional pattern on antenna 201 by controlling the phase of multiple antenna elements, thereby increasing or decreasing the gain of antenna 201 in a specific direction. Therefore, even if antenna 201 is fixed, it can transmit a directional radio wave beam in a specific (arbitrary) direction. Note that antenna 201 may be movable or rotatable. By making antenna 201 movable or rotatable, the beamformed radio wave beam can be transmitted more efficiently in a specific (arbitrary) direction.

The reflector 202 is a relay device. The reflector 202 in this embodiment 1 is movable and rotatable. In this embodiment 1, there is only one reflector 202.

The reflector 202 relays the radio wave beam transmitted from the antenna 201 toward the terminal device 100. The reflector 202 in this embodiment 1 is movable and rotatable. By moving and rotating, the reflector 202 reflects the radio wave beam emitted from the antenna 201 toward the terminal device 100.

The radio wave management server 300 is a management device. The radio wave management server 300 transmits a radio wave beam from the antenna 201 to the terminal device 100 based on the position information of the terminal device 100 and the reflector 202. The radio wave management server 300 is a computer that controls the antenna 201 by executing a program created according to the procedure described below.

(Communication control method)
FIG. 2 is a flowchart showing the procedure for implementing a communication control method by the radio wave management server 300.

First, the radio wave management server 300 measures the location of the terminal device 100 (S101). To measure the location of the terminal device 100, for example, positioning technology using ultra-wideband wireless communication (UWB (Ultra Wide Band)) is used. To measure the location of the terminal device 100, several other existing methods can also be used, such as analyzing surveillance camera footage to determine the location.

Next, the radio wave management server 300 checks whether there is an obstacle 500 on the path of the radio wave beam between the antenna 201 and the terminal device 100 (S102). If there is an obstacle 500, a radio wave blind spot 510 occurs as seen from the antenna 201, as shown in Figure 1. If such a radio wave blind spot 510 exists, the millimeter waves or terahertz waves transmitted from the antenna 201 will not directly reach the terminal device 100.

To check for the obstacle 500, a positioning technology such as LiDAR (Laser Imaging Detection and Ranging) is used. When LiDAR is used, the radio wave management server 300 compares the distance from the antenna 201 to the positioned object with the distance from the antenna 201 to the terminal device 100 to determine whether or not an obstacle 500 is present. The distance from the antenna 201 to the terminal device 100 is obtained from the position information of the terminal device 100 acquired in step S101. A camera may also be used to check for the obstacle 500. When a camera is used, the camera is installed at (or near) the antenna 201. The radio wave management server 300 determines whether or not an obstacle 500 is present based on whether or not the terminal device 100 is visible from the antenna 201 from the camera image (which may be a still image). In order to determine the presence or absence of obstacle 500 from the camera image, object detection using AI (Artificial Intelligence) may be used, for example.

If it is determined in step S102 that no obstacle 500 exists (S102: NO), the radio wave management server 300 then calculates the emission direction and focal length of the radio wave beam transmitted from the antenna 201 (S103). At this stage, no obstacle 500 exists between the antenna 201 and the terminal device 100. This state is sometimes referred to as having a line of sight (LOS (Line of Sight)) from the antenna 201 to the terminal device 100.

The radio wave management server 300 calculates the emission direction and focal length of the radio wave beam to the terminal device 100 based on the location information of the terminal device 100 acquired in S101. The emission direction and focal length of the radio wave beam to the terminal device 100 can be determined, for example, by mapping the positions of the antenna 201 and the terminal device 100 onto a two-dimensional or three-dimensional coordinate system. The emission direction of the radio wave beam is the direction of the terminal device 100 as seen from the antenna 201 in the mapped coordinate system. The focal length of the radio wave beam is the distance from the antenna 201 to the terminal device 100 in the mapped coordinate system.

The emission direction and focal length of the radio wave beam may be calculated taking into account radio wave conditions. How to check radio wave conditions will be described later.

Next, the radio wave management server 300 transmits (emits) the radio wave beam that has been beamformed to have the calculated emission direction and focal length from the antenna 201 (S105).

Then, the radio wave management server 300 determines whether or not processing has ended (S106). If processing has not ended (S106: NO), the radio wave management server 300 returns to S101 and continues processing. This makes it possible to track the position of the moving terminal device 100 and always transmit radio wave beams in the optimal direction. On the other hand, if processing has ended (S106: YES), the radio wave management server 300 ends processing. Note that processing may end, for example, in response to an end instruction from the user.

On the other hand, if it is determined in step S102 that an obstacle 500 is present (S102: YES), the radio wave management server 300 then calculates the position and orientation of the reflector 202, the emission direction of the radio wave beam to the reflector 202, and the focal length based on the position information acquired in S101 and the position information of the obstacle 500 (S104).

At this stage (S104), an obstacle 500 exists between the antenna 201 and the terminal device 100. Therefore, the radio wave management server 300 first calculates the position and orientation of the reflector 202 so that the radio wave beam from the antenna 201 is relayed to the reflector 202 and reaches the terminal device 100. The position and orientation of the reflector 202 are calculated, for example, using a two-dimensional or three-dimensional coordinate system as follows:

The radio wave management server 300 first maps the positions of the antenna 201, the terminal device 100, and the obstacle 500 in a two-dimensional or three-dimensional coordinate system. Next, from the mapped positions of the antenna 201, the terminal device 100, and the obstacle 500, the radio wave management server 300 calculates the position of the reflector 202 such that no obstacle 500 exists on either the path from the antenna 201 to the reflector 202 or on the path from the reflector 202 to the terminal device 100.

There are many positions for the reflector 202 where no obstacles 500 exist on either the path from the antenna 201 to the reflector 202 or the path from the reflector 202 to the terminal device 100. Therefore, the position of the reflector 202 that is actually determined may be, for example, the position that minimizes the travel distance from the current position of the reflector 202. This reduces the time it takes for the reflector 202 to move. Alternatively, the position of the reflector 202 that is determined may be, for example, the position that minimizes the total distance between the distance from the antenna 201 to the reflector 202 and the distance from the reflector 202 to the terminal device 100 (the position that results in the shortest distance).

Next, the radio wave management server 300 calculates the orientation of the reflector 202 whose position has been determined so that the angle of incidence and the angle of reflection of the radio wave beam are the same.

Figure 3 is a schematic diagram illustrating the angle of incidence and angle of reflection on the reflector 202. The angle of incidence α and angle of reflection β are angles relative to the normal h of the reflector 202, as shown in Figure 3.

Radio wave beams with short wavelengths, such as millimeter waves and terahertz waves, tend to travel in a straight line (they hardly diffuse). For this reason, as shown in Figure 3, the radio wave beam can reach the terminal device 100 most efficiently when the relationship of incident angle α = reflection angle β holds.

Next, the radio wave management server 300 calculates the emission direction of the radio wave beam. The emission direction of the radio wave beam is the direction of the positioned reflector 202 as viewed from the antenna 201.

Next, the radio wave management server 300 calculates the focal length of the radio wave beam. As shown in Figure 3, the focal length of the radio wave beam is the sum of the distance a from the antenna 201 to the positioned reflector 202 and the distance b from the reflector 202 to the terminal device 100 (a + b).

In addition, at this stage (S104), the emission direction and focal length of the radio wave beam may be calculated taking into account the radio wave conditions.

Next, the radio wave management server 300 transmits a radio wave beam from the antenna 201 that has been beamformed to have the calculated emission direction and focal length (S105).

Then, the radio wave management server 300 determines whether or not processing has ended (S106). If processing has not ended (S106: NO), the radio wave management server 300 returns to S101 and continues processing. This makes it possible to track the position of the moving terminal device 100 and always transmit radio wave beams in the optimal direction. On the other hand, if processing has ended (S106: YES), the radio wave management server 300 ends processing.

In this embodiment 1, by using a reflector 202, the radio wave beam can be reliably transmitted to the terminal device 100 via an optimal route that avoids the obstacle 500. In particular, in this embodiment 1, the reflector 202 can be moved and the orientation and focal length of the reflector 202 can be changed. Therefore, in this embodiment 1, even if the terminal device 100 moves, if an obstacle 500 is present, the radio wave beam can be reliably transmitted to the terminal device 100 by avoiding the obstacle.

Here we will explain how to check the signal strength.

The radio wave intensity of a radio wave beam may decrease due to interference between beams. Furthermore, the radio wave conditions may also change due to the movement of the radio wave beam emitted from the antenna 201 itself. For this reason, the radio wave conditions are constantly changing. Therefore, when determining the emission direction and focal length of the radio wave beam, it is preferable to make calculations taking into account the surrounding radio wave conditions when the radio wave beam is emitted from the antenna 201.

A relatively simple method for checking radio wave conditions is, for example, to simply estimate the radio wave conditions around the target terminal device 100 or reflector 202 using only information such as the emission direction and focal length of the multiple beams emitted by the antenna 201 itself.

Another method of checking radio wave conditions is to estimate them based on radio wave strength information obtained by placing multiple measuring devices in the target wireless area. In this method, for example, radio wave beams are emitted into the wireless area with different emission directions and focal lengths, and the measuring devices measure the radio wave strength. The measurement results are used to create a radio wave heat map. Heat maps are created for each change in radio wave beam emission direction and focal length. Machine learning is then performed using the multiple heat maps created to create an AI model. Then, when actually estimating radio wave conditions, the radio wave strength obtained from the measuring devices at that time is input into the AI model to estimate the current radio wave conditions.

(Embodiment 2)
FIG. 4 is a schematic diagram illustrating a wireless communication system 1 according to the second embodiment.

As shown in FIG. 4, the wireless communication system 1 according to the second embodiment has a reflector array 204 in which a plurality of reflectors 2021 to 2035 are arranged in an array. The reflector array 204 is a relay device. Each of the reflectors 2021 to 2035 is rotatable. The reflector array 204 according to the second embodiment does not move. The configuration other than the reflector array 204 is the same as that of the wireless communication system 1 according to the first embodiment, and therefore a description thereof will be omitted.

The basic operation of the radio wave management server 300 in embodiment 2 is the same as in embodiment 1. Therefore, the communication control method by the radio wave management server 300 is the same as the control procedure shown in Figure 2. However, step S104 is a control corresponding to the reflector array 204. Therefore, here we will explain step S104 in embodiment 2 and omit explanations of the other steps.

Furthermore, in this embodiment 2, the position of the reflector array 204 is fixed. Therefore, the position of the reflector array 204 and the positions of the individual reflectors 2021 to 2035 are stored in advance in the radio wave management server 300. Therefore, it is not necessary to measure the positions of the reflectors 2021 to 2035, which are relay devices.

In step S104 in embodiment 2, the radio wave management server 300 first maps the positions of the antenna 201, the terminal device 100, and the obstacle 500 into a two-dimensional or three-dimensional coordinate system, as in embodiment 1.

Next, based on the positions of the antenna 201, the terminal device 100, and the obstacle 500, the radio wave management server 300 selects one reflector from the reflector array 204 that is located in a position where there is no obstacle 500 on either the path from the antenna 201 to the reflectors 2021 to 2035, or from the reflectors 2021 to 2035 to the terminal device 100.

There may be a plurality of reflectors that do not have obstacles 500 on either the path from the antenna 201 to the reflectors 2021 to 2035 or on the path from the reflectors 2021 to 2035 to the terminal device 100. In such a case, the one reflector selected is, for example, the reflector that provides the shortest total distance (shortest distance) between the distance from the antenna 201 to the reflectors 2021 to 2035 and the distance from the reflectors 2021 to 2035 to the terminal device 100. Furthermore, the one reflector selected may be, for example, a reflector that does not require changing the orientation of a previously used reflector or that provides a small rotation angle.

Then, as in embodiment 1, the radio wave management server 300 calculates the orientation and focal length of the selected reflector.

Here, we will explain a case where the terminal device 100 moves. Here, we will assume that the terminal device 100 moves from position A to position B in Figure 4.

First, when the terminal device 100 is at position A, the radio wave management server 300 selects one reflector 2028 from the reflector array 204. The reflector 2028 is positioned so that it can avoid the obstacle 500 and relay the radio wave beam to the terminal device 100 at position A. The radio wave management server 300 then adjusts the orientation and focal length of the reflector 2028 and transmits the radio wave beam so that the radio wave beam from the antenna 201 reaches the terminal device 100 at position A.

After that, when the terminal device 100 moves to position B, the radio wave management server 300 selects one reflector 2035 from the reflector array 204. The reflector 2035 is positioned so that it can avoid the obstacle 500 and relay the radio wave beam to the terminal device 100 at position B. The radio wave management server 300 then adjusts the orientation and focal length of the reflector 2035 and transmits the radio wave beam so that the radio wave beam from the antenna 201 reaches the terminal device 100 at position B.

In this embodiment 2, by using a reflector array 204, it is possible to ensure that the radio wave beam reaches the terminal device 100 via the optimal route that avoids the obstacle 500. Furthermore, in this embodiment 2, if the terminal device 100 moves, the radio wave beam can be reliably relayed to the terminal device 100 by selecting a reflector in accordance with the movement of the terminal device 100. Furthermore, in this embodiment 2, multiple reflectors 2021 to 2035 are arranged in an array, so there is no need to move the reflectors. Therefore, in this embodiment 2, the radio wave beam can reach the terminal device 100 more quickly than in the case where the reflectors are moved.

In this second embodiment, the position of the reflector array 204 is fixed (does not move), but this is not limited to this and the reflector array 204 may be movable. Also, in Figure 4, the multiple reflectors 2021 to 2035 are shown as having almost no gaps between them, but there may be gaps between each reflector that allow rotation. Also, this is not limited to this and the gaps between each reflector may be larger than the gap that allows rotation of each reflector. Furthermore, the number of multiple reflectors is not limited to the 3 rows and 5 columns shown in Figure 4. Furthermore, the array structure does not have to be rectangular overall. The array structure may, for example, have a different number of reflectors in each row.

(Embodiment 3)
FIG. 5 is a schematic diagram illustrating a wireless communication system 1 according to the third embodiment.

As shown in FIG. 5, the wireless communication system 1 according to embodiment 3 has multiple repeaters 211 and 212. The repeaters 211 and 212 are relay devices. Each repeater 211 and 212 has an antenna capable of beamforming radio waves. However, the multiple repeaters 211 and 212 according to embodiment 3 do not move. The configuration other than the repeaters 211 and 212 is the same as that of the wireless communication system 1 according to embodiment 1, so a description thereof will be omitted.

In addition, in this embodiment 3, the positions of repeaters 211 and 212 are fixed. Therefore, the positions of repeaters 211 and 212 are stored in advance in the radio wave management server 300. Therefore, it is not necessary to measure the positions of repeaters 211 and 212, which are relay devices.

The basic operation of the radio wave management server 300 in embodiment 3 is the same as in embodiment 2. Therefore, the communication control procedure by the radio wave management server 300 is also the same as the control procedure shown in Figure 2. Therefore, in this embodiment 3, in step S104, instead of selecting a reflector, repeater 211 or 212 is selected that can avoid obstacles 501 and 502 and allow the radio wave beam to reach the terminal device 100.

Here, we will explain a case where the terminal device 100 moves. Here, we will assume that the terminal device 100 moves from position A to position B in Figure 5.

First, when the terminal device 100 is at position A, the radio wave management server 300 selects one repeater 211 from among multiple repeaters 211 and 212. Repeater 211 is located so that it can transmit a radio wave beam to the terminal device 100 at position A while avoiding obstacle 501. Then, the radio wave management server 300 adjusts the emission direction and focal length of the radio wave beam transmitted from repeater 211 so that the radio wave beam from antenna 201 reaches the terminal device 100 at position A, and transmits the radio wave beam. The radio wave beam from antenna 201 is beamformed so that the direction and focal length are aligned with the repeater 211. Furthermore, the radio wave beam from repeater 211 is beamformed so that the direction and focal length are aligned with the terminal device 100.

After that, when the terminal device 100 moves to position B, the radio wave management server 300 selects the repeater 212. The repeater 212 is located so that it can transmit the radio wave beam to the terminal device 100 at position B, avoiding the obstacle 502. The radio wave management server 300 then adjusts the emission direction and focal length of the radio wave beam transmitted from the repeater 212 so that the radio wave beam from the antenna 201 reaches the terminal device 100 at position B, and transmits the radio wave beam. The radio wave beam from the antenna 201 is beamformed so that the direction and focal length are to the repeater 212. The radio wave beam from the repeater 212 is also beamformed so that the direction and focal length are to the terminal device 100.

In this embodiment 3, by using repeaters 211 and 212, it is possible to ensure that the radio wave beam reaches the terminal device 100 via the optimal route that avoids obstacles. Also, in this embodiment 3, when the terminal device 100 moves, the repeaters 211 and 212 suitable for relaying are selected in accordance with the movement of the terminal device 100.

Furthermore, in this embodiment 3, by using repeaters 211 and 212, it is possible to make the radio wave beam reach the terminal device 100 without mechanical operations such as moving or rotating the reflector. Compared to reflector 202, repeaters 211 and 212 have a higher degree of freedom in the direction of emission of the radio wave beam and are also advantageous in terms of radio wave strength. Therefore, the number of repeaters 211 and 212 installed can be fewer than when multiple reflectors are installed.

In this third embodiment, multiple stationary repeaters 211 and 212 are used, but this is not limited to this, and the multiple repeaters 211 and 212 may be movable. Also, there may be only one repeater. If there is only one repeater, it is preferable that this repeater is movable. Also, the repeaters 211 and 212 may have an omnidirectional antenna that does not support beamforming. If it does not support beamforming, the efficiency is lower than that of a radio wave beam, but it is still possible for radio waves to reach the terminal device 100. In the case of a repeater with an omnidirectional antenna, the number of repeaters installed may be one or more.

(Embodiment 4)
FIG. 6 is a schematic diagram illustrating a wireless communication system 1 according to the fourth embodiment.

As shown in FIG. 6, the wireless communication system 1 according to embodiment 4 has a repeater-equipped drone 220. The repeater-equipped drone 220 is a relay device. The repeater-equipped drone 220 has an antenna 201 capable of beamforming radio waves. The repeater-equipped drone 220 moves (flies) in the air. The repeater-equipped drone 220 transmits its own position to the radio wave management server 300. Therefore, the radio wave management server 300 can always grasp the position of the repeater-equipped drone 220. The configuration other than the repeater-equipped drone 220 is the same as that of the wireless communication system 1 according to embodiment 1, and therefore a description thereof will be omitted.

The basic operation of the radio wave management server 300 in embodiment 4 is the same as in embodiment 3. Furthermore, in the procedure of the communication control method by the radio wave management server 300, in step S104, instead of selecting a repeater, the repeater-equipped drone 220 is moved to a position where it can avoid the moving obstacle 520 and allow the radio wave beam to reach the terminal device 100. Therefore, the repeater-equipped drone 220 is moved to a position where it can ensure LOS from the antenna 201 and also ensure LOS from the repeater-equipped drone 220 to the terminal device 100.

For this reason, it is preferable that the repeater-equipped drone 220 be equipped with a device for determining the positions of both the antenna 201 and the terminal device 100. The positions are determined using, for example, UWB positioning technology.

The repeater-equipped drone 220 may be equipped with a camera. The camera is used to complement UWB positioning to confirm that there are no radio wave obstructions between the antenna 201 and the drone, and between the drone and the terminal device 100 (that LOS is ensured). When a camera is installed on the repeater-equipped drone 220, the radio wave management server 300 analyzes the video data acquired by the camera and moves the repeater-equipped drone 220 to a position where LOS can be ensured both from the antenna 201 to the repeater-equipped drone 220 and from the repeater-equipped drone 220 to the terminal device 100. This allows the repeater-equipped drone 220 to adjust its position while checking LOS for both the antenna 201 and the terminal device 100, thereby improving the accuracy and time of position adjustment compared to when using UWB alone.

The position adjustment of the repeater-equipped drone 220 is performed by the radio wave management server 300. That is, the radio wave management server 300 acquires from the repeater-equipped drone 220 the position information of the antenna 201 and the terminal device 100, and further, if an obstacle is present, the position information of the obstacle. Then, as in embodiment 1, the radio wave management server 300 uses the position information of the antenna 201, the terminal device 100, and the obstacle to move the repeater-equipped drone 220 to a position where the radio wave beam can be relayed from the antenna 201 to the terminal device 100 while avoiding the obstacle. If the repeater-equipped drone 220 is an autonomous mobile drone, the radio wave management server 300 instructs the repeater-equipped drone 220 to move to that position by specifying the coordinates of a position where the radio wave beam can be relayed from the antenna 201 to the terminal device 100 while avoiding the obstacle.

Then, the radio wave management server 300 emits a radio wave beam from the antenna 201 in a direction and at a focal length to the repeater-equipped drone 220, and also emits (relays) a radio wave beam from the repeater-equipped drone 220 in a direction and at a focal length to the terminal device 100.

In addition, some or all of the functions of the radio wave management server 300 may be performed by the repeater-equipped drone 220. For example, in order to transmit a radio wave beam to the repeater-equipped drone 220, the radio wave management server 300 determines the position of the repeater-equipped drone 220 and causes the antenna 201 to emit a radio wave beam to the repeater-equipped drone 220. Meanwhile, in order to determine the position of the terminal device 100 and transmit a radio wave beam to the terminal device 100, the repeater-equipped drone 220 adjusts its own position and transmits the radio wave beam to the terminal device 100.

Here, we will explain an example of communication with a terminal device 100 within a tunnel construction site, as shown in Figure 6.

The terminal device 100 is attached to construction machinery working at a tunnel construction site. A repeater-equipped drone 220 flies within the tunnel. A moving obstacle 520 also exists within the tunnel.

The radio wave management server 300 uses UWB to determine the position of the terminal device 100 from the repeater-equipped drone 220. This allows the radio wave management server 300 to move the repeater-equipped drone 220 to a position where it can relay a radio wave beam from the antenna 201 to the terminal device 100, while avoiding obstacles. The radio wave management server 300 also checks, from the video footage from the camera mounted on the repeater-equipped drone 220, whether line of sight (LOS) is ensured for both the antenna 201 and the terminal device 100. If LOS is not ensured, the camera video is analyzed and the position of the repeater-equipped drone 220 is further adjusted.

UWB positioning of the terminal device 100 is always performed, and the radio wave management server 300 moves the repeater-equipped drone 220 in response to the movement of the obstacle 520. As for the subsequent emission of the radio wave beam, as in embodiment 3, the radio wave beam is emitted from the antenna 201 to the repeater-equipped drone 220, and then the radio wave beam is emitted (relayed) from the repeater-equipped drone 220 to the terminal device 100.

In this embodiment 4, by using a repeater-equipped drone 220, it is possible to ensure that the radio wave beam reaches the terminal device 100 via the optimal route that avoids obstacles. Furthermore, the repeater-equipped drone 220 can be repositioned more freely than the reflectors, reflector arrays, and fixed repeaters used in other embodiments. For this reason, this embodiment 4 is suitable when a moving obstacle 520 is present.

In this embodiment 4, one repeater-equipped drone 220 is used, but this is not limited to this and multiple repeater-equipped drones 220 may be used.

The above describes an embodiment of the present invention, but the present invention is not limited to the above-described embodiment.

For example, the relay device may use a combination of reflector 202, reflector array 204, repeater 211 and/or 212, and repeater-equipped drone 220. When these are used in combination, the source and destination are simply repeater 211 and/or repeater 212 and repeater-equipped drone 220 instead of antenna 201 and terminal device 100, and the communication control method can be implemented in the same way as in any of embodiments 1 to 4.

The present invention is also effective when applied to terahertz waves, which have a strong tendency to propagate in a straight line (are less prone to diffraction). The present invention can also be applied to Sub-6 5G and Wi-Fi, and is also effective when applied to microwaves.

The program according to the present invention can also be realized by a dedicated hardware circuit. The program can also be provided on a computer-readable recording medium such as a USB (Universal Serial Bus) memory or a DVD (Digital Versatile Disc)-ROM (Read Only Memory), or it can be provided online via a network such as the Internet, without relying on a recording medium. When provided online, the program is recorded on a recording medium such as a magnetic disk in a computer connected to the network.

Furthermore, the present invention is susceptible to various modifications based on the configuration described in the claims, and these modifications are also within the scope of the present invention.

This application is based on Japanese Patent Application No. 2022-005451, filed on January 18, 2022, the disclosure of which is incorporated by reference in its entirety.

The following embodiments are also within the scope of the present invention: a wireless communication system as defined in claim 1 having the features of claim 2; a wireless communication system as defined in claim 1 having the features of claim 3; a wireless communication system as defined in claim 1 having the features of claim 4; a wireless communication system as defined in any one of claims 1 to 4 having the features of claim 5; a wireless communication system as defined in claim 5 having the features of claim 6; a wireless communication system as defined in claim 5 or 6 having the features of claim 7; a wireless communication system as defined in any one of claims 1 to 4 having the features of claim 8; a wireless communication system as defined in claim 9 having the features of claim 10; a wireless communication system as defined in claim 9 having the features of claim 11; a management device as defined in claim 9 having the features of claim 12; a management device as defined in any one of claims 9 to 12 having the features of claim 13; a management device as defined in claim 13 having the features of claim 14; a management device as defined in claim 15. a management device according to claim 13 or 14; a management device according to any one of claims 9 to 12 having the characteristics of claim 16; a management device according to claim 17 having the characteristics of claim 18; a management device according to claim 18 having the characteristics of claim 19; a management device according to claim 18 or 19 having the characteristics of claim 20; a management device according to claim 17 having the characteristics of claim 21; a communication control method according to claim 22 having the characteristics of claim 23; a communication control method according to claim 22 having the characteristics of claim 24; a communication control method according to any one of claims 22 to 24 having the characteristics of claim 25; a communication control method according to claim 25 having the characteristics of claim 26; a communication control method according to claim 25 or 26 having the characteristics of claim 27; a communication control method according to any one of claims 22 to 24 having the characteristics of claim 28; a communication control program according to any one of claims 22 to 28 having the characteristics of claim 29.

1. a wireless communication system;
100 terminal device,
201 antenna,
202 Reflector,
204 reflector array,
211, 212 repeater,
220 Repeater-equipped Drone,
300 Radio wave management server.

Claims (17)

a mobile terminal device;
an antenna for transmitting a radio wave beam including a communication signal to the terminal device;
a relay device that relays the radio wave beam transmitted from the antenna to the terminal device;
a management device that acquires location information of at least one of the terminal device and the relay device, and controls the antenna to transmit the radio beam toward the relay device based on the acquired location information ,
the relay device is a reflector, and a plurality of the reflectors are arranged in an array;
The management device selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector . The wireless communication system described in claim 1, wherein the management device acquires location information of the terminal device and location information of the relay device, moves the relay device based on the location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device. The relay device is provided in plurality,
The wireless communication system described in claim 1, wherein the management device acquires location information of the terminal device, selects a relay device from among the multiple relay devices to relay the radio wave beam based on the location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device. the relay device acquires location information of the terminal device, and is capable of moving to a position from which the radio beam can be transmitted to the terminal device based on the location information of the terminal device and the antenna;
The wireless communication system according to claim 1 , wherein the management device acquires location information of the relay device and controls the antenna to transmit the radio beam toward the relay device based on the location information of the relay device. The wireless communication system described in claim 1, wherein the management device changes the orientation of the reflector based on the location information of the terminal device. A management device that acquires location information of at least one of a mobile terminal device and a relay device that relays a radio wave beam transmitted from an antenna to the terminal device, and controls the antenna to transmit the radio wave beam toward the relay device based on the acquired location information ,
the relay device is a reflector, and a plurality of the reflectors are arranged in an array;
A management device that selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector. 7. The management device of claim 6, further comprising: a control unit configured to control the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device; a control unit configured to control the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device; and a control unit configured to control the antenna to transmit the radio wave beam toward the relay device based on the location information of the relay device. The relay device is provided in plurality,
The management device described in claim 6, which selects a relay device from among a plurality of relay devices to relay the radio wave beam based on the acquired location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device. the relay device acquires location information of the terminal device, and is capable of moving to a position from which the radio beam can be transmitted to the terminal device based on the location information of the terminal device and the antenna;
The management device according to claim 6 , further comprising: a control unit configured to acquire location information of the relay device; and control the antenna to transmit the radio beam toward the relay device based on the location information of the relay device. The management device according to claim 6 , wherein the orientation of the reflector is changed based on position information of the terminal device. A relay device that relays a radio wave beam transmitted from an antenna to a mobile terminal device,
The relay device is a reflector, and multiple reflectors are arranged in an array. The relay device acquires location information of the terminal device, moves to a position where it can transmit the radio wave beam to the terminal device based on the location information of the terminal device and the antenna, and transmits the radio wave beam toward at least one reflector selected from the multiple reflectors . The relay device according to claim 11 , wherein the orientation of the reflector is changed based on position information of the terminal device. a step (a) of acquiring location information of at least one of a mobile terminal device and a relay device that relays a radio wave beam transmitted from an antenna to the terminal device;
and (b) controlling the antenna to transmit the radio wave beam toward the relay device based on the acquired location information ,
the relay device is a reflector, and a plurality of the reflectors are arranged in an array;
A communication control method , wherein step (b) selects at least one of the plurality of reflectors and transmits the radio wave beam toward the selected reflector . The relay device is provided in plurality,
The communication control method according to claim 13, wherein step (b) selects a relay device for relaying the radio wave beam from among a plurality of relay devices based on the acquired location information of the terminal device, and controls the antenna to transmit the radio wave beam toward the selected relay device . the relay device acquires location information of the terminal device, and is capable of moving to a position from which the radio beam can be transmitted to the terminal device based on the location information of the terminal device and the antenna;
The step (a) includes acquiring location information of the relay device;
The communication control method according to claim 13 , wherein said step (b) comprises controlling said antenna to transmit said radio wave beam toward said relay device based on location information of said relay device. The communication control method according to claim 13 , wherein the step (b) changes the orientation of the reflector based on location information of the terminal device. A communication control program for causing a computer to execute the communication control method according to any one of claims 13 to 16 .