WO2022091847A1

WO2022091847A1 - Wireless communication unit and wireless changing method

Info

Publication number: WO2022091847A1
Application number: PCT/JP2021/038467
Authority: WO
Inventors: 浩樹濱田
Original assignee: 古河電気工業株式会社
Priority date: 2020-10-30
Filing date: 2021-10-18
Publication date: 2022-05-05
Also published as: JP2022072588A

Abstract

Provided is a wireless communication unit capable of efficiently performing radio wave transmission/reception through an antenna even when a wireless communication device is provided under the ground.　A wireless communication unit 1 comprises: a container body 10 which is buried under the ground and which stores a cable 2 and a wireless communication device 3 having an antenna 32; a lid member 11 that closes upper end openings 10a, 10b of the container body 10; a reflected power monitor 12 that measures the magnitude of reflected power resulting from reflection, on the antenna 32 of the wireless communication device 3, of a portion of transmission power supplied to the antenna 32; a matching circuit 13 that performs impedance matching; and a control unit 14 that determines the presence or absence of an object in accordance with a ratio of the reflected power measured by the reflected power monitor 12 to the transmission power, and controls the matching circuit 3 on the basis of the ratio of the reflected power to the transmission power.

Description

How to change the wireless communication unit and wireless

The present invention relates to a wireless communication unit in which an antenna is provided at the same height as the ground or below the ground, and a method for changing radio using this wireless communication unit.

In devices that perform wireless communication, resonance circuits are generally used from the viewpoint of improving transmission efficiency. For example, in a traffic safety system or an automatic driving system, information is transmitted by wireless communication between a terrestrial communicator installed on the ground and an on-board communicator installed on a vehicle. Since both the antennas of these terrestrial communicators and on-board communicators are mounted outdoors, debris such as mud and snow easily adheres to them, and such adhesion may cause problems such as noise and reduce communication efficiency. be.

In order to prevent a decrease in communication efficiency due to such a failure, for example, Patent Document 1 includes a resonance control unit that controls constants of elements constituting the resonance circuit based on measurement results of voltage and current of the resonance circuit. The wireless communication device is listed.

International Publication No. 2018/037698

In recent years, in order to avoid damage caused by the collapse of utility poles due to typhoons and earthquakes, cables such as communication lines and power lines installed on outdoor utility poles are housed in containers and used as electric wire utility tunnels in the ground or in the road surface. Efforts are underway to eliminate utility poles. In order to promote efforts to eliminate utility poles through electric wire utility tunnels, in addition to cables, wireless communication devices such as antennas for portable communication devices that were previously installed on utility poles should also be installed underground, such as on the road surface. It has been demanded. In particular, in 5th generation (5G) mobile communication systems, the reach of radio waves is narrow, so wireless communication devices such as antennas that transmit or receive radio waves may be installed in the ground or on the road surface at short distance intervals. It has been demanded. Furthermore, for the purpose of detecting pedestrians and vehicles and communicating with vehicles, such as accident prevention at intersections, investigation of traffic conditions such as traffic volume, and communication with self-driving cars, wireless communication devices such as antennas are used on the ground. It is required to be installed inside.

However, the wireless communication device described in Patent Document 1 is intended to be installed outdoors such as outside a vehicle, and is not expected to be installed at least underground. When installing a wireless communication device such as an antenna in the ground, when communicating with the wireless communication device on the ground, it may be disturbed by mud, rain, snow, etc. on the ground surface, as well as people and vehicles passing on the ground. The communication efficiency may decrease due to the above.

The present invention provides a wireless communication unit that employs a configuration that enables efficient transmission and reception of radio waves by an antenna even if a wireless communication device is installed underground, and a method for changing radio waves using this wireless communication unit. To provide.

The present inventors have made extensive studies to solve the above-mentioned problems. As a result, the presence or absence of an object that substantially affects the communication efficiency is determined from the measurement result of the reflected power monitor that measures the magnitude of the reflected power generated by reflecting a part of the transmitted power supplied to the antenna. When it is determined that there is an object in the determination of the presence or absence of an object, the antenna impedance matching is performed by a matching circuit based on the ratio of the reflected power to the transmission power, so that the wireless communication device is provided in the ground. However, they have found that it is difficult for the communication efficiency to decrease due to fluctuations in reflected power, etc., and have completed the present invention.

That is, the gist structure of the present invention is as follows.
(1) A container body that is buried in the ground and houses a wireless communication device having an antenna and a cable, a lid member that closes the upper end opening of the container body, and transmission power supplied to the antenna of the wireless communication device. A part of the above is based on the ratio of the reflected power measured by the antenna to the transmitted power of the reflected power measured by the reflected power monitor, the matching circuit that performs impedance matching, and the reflected power monitor that measures the magnitude of the reflected power generated by the reflected power of the antenna. A wireless communication unit including a control unit that determines the presence or absence of an object and controls the matching circuit based on the ratio of the reflected power to the transmission power.
(2) Further provided with an object detecting means for determining the presence or absence of the object, the control unit may use the object detecting means to determine the presence or absence of the object and the ratio of the reflected power to the transmission power. The wireless communication unit according to (1) above, which controls the matching circuit based on the result of the above.
(3) The control unit measures a change over time in the numerical value of the parameter due to the reflected power, and when the measured numerical value of the parameter changes so as to exceed a reference value, the duration of the change. The wireless communication unit according to (1) or (2) above, which is configured to determine whether or not the object is continuously stationary.
(4) The control unit is configured to detect and record a change over time in the value of the reflected power as a parameter caused by the reflected power, and the change so that the value of the reflected power exceeds the reference value. The wireless communication unit according to (3) above, which is configured to determine that there is continuity of the change when the above time is exceeded.
(5) The wireless communication device is based on the result of the presence / absence of the object detected by the object detecting means and the result of the determination of the continuity of the change performed by the control unit. The wireless communication unit according to (3) or (4) above, which is configured to change the output of transmission power.
(6) The item according to any one of (1) to (5) above, wherein the wireless communication unit further includes a load detecting means for detecting the presence or absence of the object staying on the upper surface of the lid member by a load. Wireless communication unit.
(7) The wireless communication unit includes a plurality of the load detecting means, and is configured to determine whether or not to change the output of the transmitted power based on the detection results of the plurality of load detecting means (6). ) Described in the wireless communication unit.
(8) The wireless communication unit is at least one of a temperature measuring means for measuring the temperature of an object located on the lid member and a precipitation information acquiring means capable of acquiring precipitation information around the wireless communication unit. Any of the above (1) to (7), which is configured to be communicable with the additional means and is configured to change the output of the transmission power based on the information acquired by the additional means. The wireless communication unit according to item 1.
(9) A method for changing radio in a wireless communication unit including a container body in which a wireless communication device having an antenna and a cable is housed, and a lid member for closing the upper end opening of the container body. A part of the transmission power supplied to the antenna is reflected by the antenna, and the magnitude of the reflected power is measured. An object detection step for determining the presence or absence of an antenna, a determination result for the presence or absence of the object in the object detection step, and an impedance matching step for performing impedance matching based on the ratio of the reflected power to the transmission power. How to change the radio in a wireless communication unit, including.
(10) The method for changing the radio in the wireless communication unit is to measure the change over time in the numerical value of the parameter due to the reflected power, and when the measured numerical value of the parameter changes to exceed the reference value. The method for changing radio in the wireless communication unit according to (9) above, further comprising an object retention continuity determination step of determining whether or not the object is stationary from the duration of the change.
(11) The impedance matching step is based on the result of the presence / absence of the object detected in the object detection step and the result of the determination of the continuity of the change performed in the object retention continuity determination step. The method for changing the radio in the wireless communication unit according to (10) above, which is configured to change the output of the transmission power.

According to the present invention, a wireless communication unit adopting a configuration capable of efficiently transmitting and receiving radio waves by an antenna even if a wireless communication device is provided underground, and a change of radio using this wireless communication unit. A method can be provided.

1A and 1B are views showing an example of the structure of a wireless communication unit according to the first embodiment according to the present invention, FIG. 1A is a plan view, FIG. 1B is a diagram of FIG. 1A. a sectional view (horizontal sectional view). FIG. 2 is a schematic view showing an example of a state in which the accommodation unit of the first embodiment according to the present invention is installed on a paved road. FIG. 3 is a schematic view showing an example of the structure of the main body of the accommodating unit according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing an example of the structure of the wireless communication unit of the second embodiment according to the present invention. FIG. 5 is a cross-sectional view showing an example of the structure of the wireless communication unit according to the third embodiment of the present invention. FIG. 6 is a flowchart of a method of changing the radio according to the present invention. FIG. 7 is a flowchart of another embodiment of the radio modification method according to the present invention.

Next, the wireless communication unit of some embodiments of the present invention will be described below.

<First Embodiment>
1A and 1B are views showing an example of the structure of a wireless communication unit according to the first embodiment according to the present invention, FIG. 1A is a plan view, FIG. 1B is a diagram of FIG. 1A. a sectional view (horizontal sectional view). FIG. 2 is a schematic view showing an example of a state in which the accommodation unit of the first embodiment according to the present invention is installed on a paved road. FIG. 3 is a schematic view showing an example of the structure of the main body of the accommodating unit according to the first embodiment of the present invention.

The wireless communication unit 1 of the present invention is buried in the ground, and as shown in FIG. 1, the container body 10 in which the wireless communication device 3 having an antenna 32 and the cable 2 are housed, and the container body 10 A lid member 11 for closing the

upper end openings

10a and 10b is provided. Here, the wireless communication unit 1 is impedance-matched with a reflected power monitor 12 that measures the magnitude of the reflected power generated by reflecting a part of the transmitted power supplied to the antenna 32 of the wireless communication device 3 by the antenna 32. The presence or absence of an object is determined from the ratio of the reflected power measured by the reflected power monitor 12 to the transmission power of the matching circuit 13 and the matching circuit 13 is controlled based on the ratio of the reflected power to the transmission power. A control unit 14 is provided. Specifically, the control unit 14 determines the presence / absence of an object existing on the lid member 11.

As a result, the ratio of the reflected power to the transmitted power is obtained from the magnitude of the reflected power measured by the reflected power monitor 12, and from this ratio, it is located on the lid member 11 on the antenna 32 and communicates. It is possible to determine the presence or absence of an object that substantially affects efficiency. Further, when it is determined that there is an object in the determination of the presence / absence of an object, the matching circuit 13 can appropriately perform impedance matching of the antenna 32 based on the ratio of the reflected power to the transmission power. As a result, even if the wireless communication device 3 is provided underground, radio waves can be efficiently transmitted and received by the antenna.

(Wireless communication unit)
The wireless communication unit 1 is used, for example, in a 5G communication system, and as shown in FIG. 1, the container body 10 is buried in the ground and houses a wireless communication device 3 having an antenna 32 and a cable 2. And a lid member 11 for closing the

upper end openings

10a and 10b of the container body 10. Here, as shown in FIG. 1, in the wireless communication unit 1, in the internal space S formed by the container body 10 and the lid member 11, cables 2 such as the communication line 21 and the power line 22 are connected to each other in the width of the container body 10. It is housed in a state of being arranged in a direction parallel to the direction Y.

(Container body, lid member)
The container body 10 is a member capable of accommodating other components included in the wireless communication unit 1, for example, as shown in FIG. 1, a cable 2, a main body 31 of a wireless communication device 3 described later, and the like. The antenna 32, the output change presence / absence determining means 72, which will be described later, and the like can be accommodated. Further, a plurality of container main bodies 10 are connected and continuously arranged so that the internal spaces S communicate with each other along the length direction X. Inside the plurality of container bodies 10, an elongated cavity extending in the front-rear direction, that is, in the length direction X of the container body 10, is formed, and the cable 2 is housed in the elongated cavity. The antenna 32 may be directly connected to the main body 31 of the wireless communication device 3 (antenna integrated configuration), or may be connected to the main body 31 of the wireless communication device 3 via a cable (separate antennas). (Body structure) may be used.

The shape of the portion of the container body 10 in which the cable 2 is accommodated is concave when viewed in a cross section intersecting the length direction X of the container body 10 at right angles from the viewpoint of facilitating the accommodation of the cable 2. It is preferable to have a shape that becomes.

The lid member 11 is preferably a plate-shaped member having both sides formed in a flat surface shape, and in a state where the

upper end openings

10a and 10b of the container body 10 are closed, the above-ground space and the underground internal space S are combined. It is partitioned. In the state where the

upper end openings

10a and 10b of the container body 10 are closed, the lid member 11 is preferably arranged with the upper surface 11a having a height positional relationship similar to that of the ground, and more preferably flush with the ground G. .. The lower limit of the average thickness of the lid member 11 is preferably 2.0 cm, more preferably 3.0 cm, and particularly preferably 4.0 cm from the viewpoint of ensuring the strength to withstand the load of a person walking on the ground. On the other hand, the upper limit of the average thickness of the lid member 11 is preferably 20 cm, more preferably 17 cm, and particularly preferably 15 cm from the viewpoint of ensuring good transmission performance of the electromagnetic wave E transmitted and received by the antenna 32.

The material of the container body 10 and the lid member 11 is preferably resin. When these are composed of resin, the electromagnetic wave E transmitted to and received from the antenna 32 causes a loss in the container body 10 and the lid member 11, and it is possible to prevent a decrease in communication efficiency due to the loss of the electromagnetic wave E. In addition, the container body 10 and the lid member 11 can be made lighter, and can be easily carried when the wireless communication unit 1 is installed or dug up. Further, since the cutting process at the site is facilitated, it is possible to facilitate the installation of the wireless communication unit 1 in a curved portion or a portion having a change in slope.

Here, it is preferable that the container body 10 and the lid member 11 are formed of, for example, a polyolefin resin such as polyethylene and polypropylene, a polyester resin such as polyethylene terephthalate, and a resin material such as polystyrene resin. Further, the container body 10 and the lid member 11 may be formed by using one kind of the above-mentioned resin material alone, or may be formed by using two or more kinds of the above-mentioned resin materials.

The wireless communication unit 1 is buried in the ground. For example, as shown in FIG. 2, the container body 10 and the lid member 11 are buried so that the upper end thereof is located near the ground G. At this time, it is preferable that the upper surface 11a of the lid member 11 is arranged in the same height positional relationship as the ground G. Here, it is preferable that the wireless communication unit 1 is embedded on the sidewalk 81 side of the road 8 having the sidewalk 81 and the roadway 82. In the wireless communication unit 1 of the present invention, the upper surface 11a of the lid member 11 may form a part of the passage surface of the pedestrian P or the like, but the communication efficiency is unlikely to decrease due to the passage of the pedestrian P or the like.

Further, in the wireless communication unit 1, it is preferable that a plurality of container bodies 10 are arranged so that the length direction X of the container body 10 is along the traveling direction of a road such as a motorway or a general road. This makes it possible to provide a plurality of wireless communication devices 3 along the traveling direction of the road, so that wireless communication can be performed in a wider range. The direction in which the plurality of container bodies 10 are arranged is the direction along the extending direction of the cable, and is not necessarily limited to the traveling direction of the road 8.

Examples of the ground surface G in which the wireless communication unit 1 is buried include a paved road and a road surface of a road 8 which is an unpaved road. Among these, as the paved road, a road 8 which is a paved road having a paved layer 83 mainly composed of asphalt and a ground 84 mainly composed of soil and located in a lower layer can be mentioned.

(cable)
Examples of the cable 2 accommodated in the wireless communication unit 1 include a communication line 21 for transmitting data received or transmitted by the wireless communication device 3 described later, and a power line 22 for supplying power to the wireless communication device 3, and there are a plurality of types. Cable 2 can be accommodated in the internal space S. Further, the wireless communication unit 1 may accommodate other communication lines or power lines (low voltage power lines).

(Wireless communication equipment)
As shown in FIG. 1, the wireless communication device 3 housed in the wireless communication unit 1 has a main body 31 connected to the communication line 21 and the power line 22, and an antenna 32 connected to the main body 31. ing.

The main body 31 is connected to the communication line 21 via a connection line 23 capable of data communication such as an optical fiber, and can transmit and receive signals to and from the communication line 21. Further, the main body 31 is connected to the power line 22 via the electric connection line 24, and power is supplied from the power line 22.

The main body 31 has at least one of a role of transmitting transmission data transmitted from the communication line 21 as radio waves from the antenna 32 and a role of converting the radio waves received by the antenna 32 into received data and sending them to the communication line 21. Have one. Here, as an example of the main body portion 31, for example, the one having the structure shown in FIG. 3 can be mentioned. More specifically, as the main body 31 having a role of transmitting transmission data from the antenna 32, a modulator 31a that modulates the transmission data and a carrier wave such as an RF signal based on the transmission data modulated by the modulator 31a are used. Examples thereof include an oscillator 31b that oscillates, an amplifier 31c that amplifies a carrier wave from the oscillator 31b, and a filter 31d that removes unnecessary frequency components from the signal amplified by the amplifier 31c. At this time, a radio wave having a specific frequency that has passed through the filter 31d can be transmitted from the antenna 32. On the other hand, the main body 31 having a role of converting the radio wave received by the antenna 32 into the received data includes a filter 31f that removes unnecessary frequency components from the radio wave received from the antenna 32 and a weak radio wave that has passed through the filter 31f. Examples thereof include an amplifier 31 g for amplification and a demodulator 31h for converting radio waves amplified by the amplifier 31 g into transmission data. In addition, the main body 31 may have a transmission / reception changeover switch 31e for switching between a transmission side circuit and a reception side circuit.

The antenna 32 is connected to the main body 31 via an electrical connection line 33. The main body 31 transmits the electromagnetic wave E to, for example, a portable wireless communication terminal (not shown) moving on the ground via the antenna 32, and receives the electromagnetic wave E from the wireless communication terminal to perform wireless communication. Here, the electromagnetic wave E transmitted and received by the antenna 32 can determine characteristics such as frequency according to a communication distance and the like, and an example thereof is a radio wave for communication such as 5G communication.

(Reflected power monitor)
The wireless communication unit 1 of the present invention comprises a reflected power monitor 12 that measures the magnitude of the reflected power generated by a part of the transmission power supplied to the antenna 32 of the wireless communication device 3 being reflected by the antenna 32. Be prepared.

When the electromagnetic wave E is transmitted from the antenna 32 of the wireless communication device 3, if impedance matching is not obtained at the feeding point, the antenna 32 cannot radiate sufficient radio waves (electric power) required for design. Here, the ratio of the reflected power to the transmission power becomes the minimum when the transmission power of a specific frequency is supplied to the antenna 32, and when the transmission power of a frequency different from that frequency is supplied to the antenna 32, the reflected power to the transmission power is supplied. The ratio of is large. Therefore, the wireless communication unit 1 is configured to perform impedance matching so that the reflected power is minimized.

Here, if an object is located on the path of the electromagnetic wave E transmitted from the antenna 32, impedance matching cannot be obtained due to the influence of this object, and the reflected power becomes large. For example, when an electromagnetic wave E is transmitted upward from the antenna 32, if an object is located on the upper surface 11a of the lid member 11, impedance matching cannot be obtained due to the influence of this object, and the reflected power becomes large. This is because the degree of influence on the frequency characteristics of the antenna changes depending on the distance from the antenna and the size of the dielectric (for example, the object mounted on the upper surface 11a of the lid member 11), and the magnitude of the reflected power increases. It is thought that this is because it fluctuates.

Therefore, the wireless communication unit 1 of the present invention is configured to focus on the ratio of the reflected power to the actually obtained transmission power and measure the magnitude of the reflected power using the reflected power monitor 12. As a result, impedance matching can be performed based on the ratio of the reflected power to the transmission power, so that radio waves can be efficiently transmitted and received by the antenna 32.

(Object detection means)
In addition to the reflected power monitor 12, the wireless communication unit 1 of the present invention preferably further includes an object detecting means 15 for determining the presence or absence of an object. Specifically, the object detecting means 15 determines the presence or absence of an object located on the upper surface 11a or the like of the lid member 11. As a result, in addition to the ratio of the reflected power to the transmission power, the presence or absence of the object can be grasped by the object detecting means 15, so that the accuracy of grasping the presence or absence of the object is improved and the timing is more appropriate. Impedance matching of the antenna 32 can be performed.

The object detecting means 15 is not particularly limited, but for example, a weight sensor or the like can be used.

(Matching circuit)
The matching circuit 13 performs impedance matching, and more specifically, impedance matching is performed based on a control signal from the control unit 14 described later. As a result, impedance matching can be appropriately performed based on the determination result regarding the presence or absence of an object and the ratio of the reflected power to the actually measured transmission power, so that the antenna 32 of the wireless communication device 3 and the like can be placed in the ground. Even in a situation where the magnitude of the reflected power is likely to fluctuate depending on the position and size of an object existing on the upper surface 11a of the lid member 11, the reflected power is suppressed and radio waves are transmitted and received by the antenna 32. It can be done efficiently.

In particular, in the embodiment in which the wireless communication unit 1 includes the object detecting means 15, the existence of an object obtained from the result of the ratio of the reflected power measured by the reflected power monitor 12 to the transmission power and the detection result by the object detecting means 15. It is preferable that the control unit 14 described later controls the matching circuit 13 based on the determination result of the presence / absence of the above, thereby performing impedance matching.

As an example of the matching circuit 13, for example, in the main body portion 31 of the structure shown in FIG. 3, a matching circuit provided at a position directly connected to the antenna 32 and having variable capacitance portions V1 and V2 on both sides of the coil L can be mentioned. be able to. At this time, the control unit 14 described later transmits a control signal to the matching circuit 13 and controls the matching circuit so as to change the capacities of the variable capacitance units V1 and V2 provided on both sides of the coil L. Impedance matching can be performed appropriately. As a result, the reflected power can be suppressed and the radio waves can be efficiently transmitted and received by the antenna 32.

(Control unit)
Further, the wireless communication unit 1 determines the presence or absence of an object from the ratio of the reflected power measured by the reflected power monitor 12 to the transmission power, and also sets the matching circuit 13 based on the ratio of the reflected power to the transmission power. A control unit 14 for transmitting a control signal to be controlled is provided. As a result, the presence or absence of an object is determined based on the ratio of the reflected power measured to the transmission power, and impedance matching is performed by the control of the matching circuit 13, so that the position is located on the upper surface 11a of the lid member 11. It is possible to efficiently transmit and receive electric power by the antenna 32 according to the presence or absence of an object and the actual state in which the object exists.

Here, the determination of the presence / absence of an object in the control unit 14 can be performed by obtaining in advance the magnitude of the reflected power when there is no object for determining the presence / absence, and comparing the magnitude with the measured value. .. For example, in order to determine the presence or absence of an object located on the upper surface 11a of the lid member 11, the magnitude of the reflected power when the object is not located on the upper surface 11a of the lid member 11 is determined in advance, and the magnitude and the measured value are determined. It can be done by comparing.

Further, the control unit 14 measures the change over time in the numerical value of the parameter due to the reflected power, and when the numerical value of the measured parameter changes so as to exceed the reference value, the change duration is used to determine the change of the object. It is preferably configured to determine if the stagnation is continuous. As a result, when the duration of change is long, it is determined that the object stays on the upper surface 11a of the lid member 11 continuously, so that the existence of a temporary object due to the passage of the pedestrian P or the like can be determined. It will be possible to distinguish it from continuous object retention such as snow cover and puddles. As a result, the control unit 14 can appropriately perform impedance matching in the former case and the latter case.

Further, the control unit 14 is configured to detect and record a change over time in the value of the reflected power as a parameter caused by the reflected power, and changes such that the value of the reflected power exceeds the reference value for a specified time or longer. If so, it is configured to determine that there is continuity of change. As a result, it is determined from the change over time in the numerical value of the reflected power whether or not the stagnant object affects the reflected power. Therefore, select the case where the reflected power is continuously affected. Impedance matching can be performed. Here, the predetermined time for determining that there is continuity of change is not particularly limited, but may be, for example, 1 second or more and 300 seconds or less, preferably 5 seconds or more and 20 seconds or less.

When the control unit 14 determines that there is continuity of change, it is predicted that the object is stationary on the upper surface 11a of the lid member 11, so impedance matching can be performed according to such a case. can. At this time, the wireless communication device 3 determines the result of the presence / absence of the object detected by one or both of the reflected power monitor 12 and the object detecting means 15 and the determination of the continuity of the change performed by the control unit 14. It is preferable that the output of the transmission power is changed based on the result of the above. In particular, when the control unit 14 determines that there is continuity of change, it is predicted that the stationary object is not the pedestrian P, so that the output of the transmission power supplied to the antenna 32 is increased and the reflected power is used. The decrease in output can be compensated.

On the other hand, if the continuation of the change ends before the predetermined time, the impedance matching by the matching circuit 13 described later also ends at that point.

As a parameter caused by the reflected power, for example, the magnitude of the reflected power can be mentioned. Here, the parameters caused by the reflected power can be measured using, for example, the reflected power monitor 12. In particular, the numerical value of the reflected power measured by the reflected power monitor 12 is recorded over time, the continuity of the change is determined based on the change over time, and the matching circuit 13 is used based on the determination result. A configuration that performs impedance matching is preferable.

(Load detection means)
It is particularly preferable that the wireless communication unit 1 of the present embodiment includes load detecting means 71a to 71d for detecting the presence or absence of an object staying on the upper surface 11a of the lid member 11 by a load. By continuously measuring the load applied to the lid member 11 using the load detecting means 71a to 71d, the presence or absence of the pedestrian P staying on the upper surface 11a of the lid member is detected from the numerical value of the load. Therefore, when an object is stationary on the upper surface 11a of the lid member and the object is not a pedestrian P, the output of the transmission power supplied to the antenna 32 can be increased to compensate for the decrease in the output due to the reflected power. .. At the same time, when the pedestrian P is stopped on the upper surface 11a of the lid member, the safety for the pedestrian P can be enhanced by not increasing the output of the transmission power supplied to the antenna 32.

Here, as shown in FIG. 1A, the wireless communication unit 1 includes a plurality of load detecting means 71a to 71d such as a load sensor, and the antenna 32 is based on the detection results by the plurality of load detecting means 71a to 71d. It is preferable that it is configured to determine whether or not the output of the transmission power to is changed. When the pedestrian P is located on the upper surface 11a of the lid member, the load applied to the lid member 11 is often unevenly applied. Therefore, when the detection results by the plurality of load detecting means 71a to 71d are different, it is predicted that the pedestrian P is stationary on the upper surface 11a of the lid member, so that the transmission power supplied to the antenna 32 is transmitted. By not increasing the output, the safety for the pedestrian P can be enhanced.

(How to change the radio)
FIG. 6 is a flowchart of a method of changing the radio according to the present invention. The method of changing the radio of the present invention is the method of changing the radio in the above-mentioned radio communication unit 1, and a part of the transmission power supplied to the antenna 32 of the radio communication device 3 is reflected by the antenna to generate reflection. An object detection step (ST1) that measures the magnitude of electric power and determines the presence or absence of an object located on the upper surface 11a or the like of the lid member 11 from the ratio of the reflected power measured by the reflected power monitor 12 to the transmitted power. ), And an impedance matching step (ST2) for performing impedance matching based on the result of determining the presence or absence of an object in the object detection step (ST1) and the result of the ratio of the reflected power to the transmission power. As a result, impedance matching can be appropriately performed according to the presence of an object, so that even if the wireless communication device 3 is provided underground, radio waves can be efficiently transmitted and received by the antenna 32.

At this time, the numerical value of the parameter caused by the reflected power, for example, the change over time in the magnitude of the reflected power is measured, and when the numerical value of the measured parameter changes so as to exceed the reference value, the duration of this change. Therefore, it is preferable to perform an object retention continuity determination step (ST3) for determining whether or not the object is stationary, and then perform an impedance matching step (ST2) based on the object retention continuity determination step (ST3). This makes it possible to distinguish between the existence of temporary objects due to the passage of pedestrians P and the continuous retention of objects such as snow and puddles, and to perform impedance matching in an appropriate form according to each. can.

Here, the impedance matching step (ST2) determines the result of the presence or absence of the object detected in the object detection step (ST1) and the determination of the continuity of the change performed in the object retention continuity determination step (ST3). It is preferable that the output of the transmission power supplied to the antenna is changed based on the result. For example, as shown in the flowchart of FIG. 7, it is determined in the object detection step (ST1) that an object is present on the upper surface 11a of the lid member 11, and the parameter values due to reflected power are continuously changed with time. It is preferable to increase the output of the transmission power supplied to the antenna 32 when it is determined that there is a property. In particular, when the control unit 14 determines that there is continuity of change, it is predicted that the stationary object is not the pedestrian P, so that the output of the transmission power supplied to the antenna 32 is increased and the reflected power is used. The decrease in output can be compensated.

<Second Embodiment>
FIG. 4 is a cross-sectional view showing an example of the structure of the wireless communication unit of the second embodiment according to the present invention. In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified, and the differences will be mainly described.

In the above-mentioned first embodiment, as shown in FIGS. 1A and 1B, a configuration including load detecting means 71a to 71d provided on the upper surface 11a of the lid member is shown, but the present invention is not limited thereto. For example, as in the wireless communication unit 1A shown in FIG. 4, a temperature measuring means 73 for measuring the temperature of an object located on the lid member is configured as an additional means so as to be communicable with the wireless communication unit 1A, and added. It is also preferable that the output of the transmission power supplied to the antenna 32 is changed based on the information acquired by the temperature measuring means 73, which is the means of the above.

As a result, the temperature measuring means 73 continuously measures the temperature of the upper surface 11a of the lid member, thereby detecting the presence or absence of the pedestrian P staying on the upper surface 11a of the lid member. When the object is stationary and the object is not the pedestrian P, the output of the transmission power supplied to the antenna 32 can be increased to compensate for the decrease in the output due to the reflected power. At the same time, when the pedestrian P is stopped on the upper surface 11a of the lid member, the safety for the pedestrian P can be enhanced by not increasing the output of the transmission power supplied to the antenna 32.

<Third Embodiment>
FIG. 5 is a cross-sectional view showing an example of the structure of the wireless communication unit according to the third embodiment of the present invention. In the following description, the same components as those in the first embodiment or the second embodiment are designated by the same reference numerals, the description thereof will be omitted or simplified, and the differences will be mainly described.

In the above-mentioned first embodiment, as shown in FIGS. 1A and 1B, a configuration including load detecting means 71a to 71d provided on the upper surface 11a of the lid member is shown, but the present invention is not limited thereto. For example, as in the wireless communication unit 1B shown in FIG. 5, the precipitation information acquisition means 74 capable of acquiring precipitation information around the wireless communication unit 1B is configured to be communicable with the wireless communication unit 1B as an additional means. It is also preferable that the output of the transmission power supplied to the antenna 32 is changed based on the information acquired by the precipitation information acquisition unit 74, which is an additional means.

In the present embodiment, the precipitation information acquisition means 74 obtains precipitation information around the wireless communication unit 1B, and the information on the presence or absence of an object detected by the reflected power monitor 12 or the like is collated with the precipitation information to obtain the lid member. It is possible to predict whether or not the object staying on the upper surface 11a is a puddle due to snow or precipitation. Therefore, when an object stays on the upper surface 11a of the lid member and it is predicted that the object is due to snow or precipitation, the output of the transmission power supplied to the antenna 32 is increased to reduce the output due to the reflected power. Can be supplemented. At the same time, when the pedestrian P is stopped on the upper surface 11a of the lid member, the safety for the pedestrian P can be enhanced by not increasing the output of the transmission power supplied to the antenna 32.

1, 1A Wireless communication unit 10

Container body

10a, 10b Upper end opening of container body 11 Lid member 11a Upper surface of lid member 11b Lower surface of lid member 12 Reflected power monitor 13 Matching circuit 14 Control unit 15 Object detection means 2 Cable 21 Communication line 22

Power line

23, 24, 33 Connection line 3 Wireless communication device 31 Main unit 31a Modulator 31b Oscillator 31c,

31g Amplifier

31d, 31f Filter 31e Transmission / reception changeover switch 31h Demodulator 32 Antenna 71a to 71d Load detection means 72 Output change presence / absence determination means 73 Temperature measuring means 8 Road 81 Sideway 82 Road 83 Pavement layer 84 Ground E Electromagnetic wave G Ground (ground surface)
P Pedestrian C Vehicle L Coil S Internal space V1, V2 Variable capacity part X Length direction of container body Y Width direction of container body ST1 Object detection process ST2 Impedance matching process ST3 Object retention continuity determination process

Claims

The main body of the container, which is buried in the ground and houses wireless communication equipment with an antenna and cables,
A lid member that closes the upper end opening of the container body,
A reflected power monitor that measures the magnitude of the reflected power generated by reflecting a part of the transmitted power supplied to the antenna of the wireless communication device by the antenna, and
A matching circuit that performs impedance matching and
It is provided with a control unit that determines the presence or absence of an object from the ratio of the reflected power measured by the reflected power monitor to the transmitted power and controls the matching circuit based on the ratio of the reflected power to the transmitted power. Wireless communication unit.
Further provided with an object detecting means for determining the presence or absence of the object,
The first aspect of the present invention, wherein the control unit controls the matching circuit based on the result of determination of the presence / absence of the object in the object detection means and the result of the ratio of the reflected power to the transmission power. Wireless communication unit.
The control unit measures a change over time in the numerical value of the parameter due to the reflected power, and when the measured numerical value of the parameter changes so as to exceed a reference value, the change is determined from the duration of the change. The wireless communication unit according to claim 1 or 2, which is configured to determine whether or not the object is stationary.
The control unit is configured to detect and record a change over time in the numerical value of the reflected power as a parameter caused by the reflected power.
The wireless communication unit according to claim 3, wherein it is determined that there is continuity of the change when the change such that the numerical value of the reflected power exceeds the reference value is made for a specified time or more.
The wireless communication device has the transmission power of the transmission power based on the result of the presence / absence of the object detected by the object detection means and the result of the determination of the continuity of the change performed by the control unit. The wireless communication unit according to claim 3 or 4, which is configured to change the output.
The wireless communication unit according to any one of claims 1 to 5, further comprising a load detecting means for detecting the presence or absence of the object staying on the upper surface of the lid member by a load.
The wireless communication unit includes a plurality of the load detecting means.
The wireless communication unit according to claim 6, which is configured to determine whether or not to change the output of the transmission power based on the detection results of the plurality of load detecting means.
The wireless communication unit is added with at least one of a temperature measuring means for measuring the temperature of an object located on the lid member and a precipitation information acquiring means capable of acquiring precipitation information around the wireless communication unit. Configured to be able to communicate with the means of
The wireless communication unit according to any one of claims 1 to 7, which is configured to change the output of the transmission power based on the information acquired by the additional means.
A method for changing radio in a wireless communication unit including a container body in which a wireless communication device having an antenna and a cable are housed, and a lid member for closing the upper end opening of the container body.
A part of the transmission power supplied to the antenna of the wireless communication device is reflected by the antenna, and the magnitude of the reflected power is measured, and the ratio of the reflected power measured by the reflected power monitor to the transmission power is used. , An object detection process that determines the presence or absence of an object,
An impedance matching step of performing impedance matching based on a determination result of the presence or absence of the object in the object detection step and the ratio of the reflected power to the transmission power.
How to change the radio in a wireless communication unit, including.
The method of changing the radio in the wireless communication unit measures the change over time in the numerical value of the parameter due to the reflected power, and when the measured numerical value of the parameter changes so as to exceed the reference value, the change is described. The method for changing radio in a wireless communication unit according to claim 9, further comprising an object retention continuity determination step of determining whether or not the object is stationary from the duration of the object.
The impedance matching step is based on the result of the presence / absence of the object detected in the object detection step and the result of the determination of the continuity of the change performed in the object retention continuity determination step. The method for changing radio in a wireless communication unit according to claim 10, which is configured to change the output of transmission power.