JP2020017835A - Radio communication system - Google Patents

Abstract

To obtain a radio communication system increasing the reliability of wireless network between the points of high priority requiring continuous communication.SOLUTION: A movable radio relay device 200 relaying communication of radio apparatuses 210 and 220 includes an obstacle position specification part 102 for monitoring an obstacle becoming radio wave hindrance and specifying the position thereof, an interference wave level detector 104 for detecting the reception level of the interference wave, a monitor information section 108 for monitoring and storing the position of the obstacle and the reception level of the interference wave, an obstacle interference wave identification section 109 for identifying whether the obstacle is generating the interference wave, an abnormality determination part 110 for determining an abnormality blocking radiocommunication of the radio relay device, a movable range information section 111 for managing the movement propriety information indicating a position to which the radio relay device can move, and an own device position control section 112 for determining the movement destination of the radio relay device on the basis of the movement propriety information when the abnormality determination part determines abnormality, and controlling that position.SELECTED DRAWING: Figure 1

Description

  The present application relates to a wireless communication system that increases the reliability of a wireless network between high-priority points that require continuous communication.

  2. Description of the Related Art In recent years, wireless communication has become widespread in communication systems for consumer devices such as mobile phones and smartphones. In recent years, wireless applications have expanded to industrial devices such as remote I / O (input / output), sensors, and robots because of the advantages of miniaturization and cost reduction of wireless devices, and reduction of wiring and cable costs. I have. Furthermore, as represented by the Internet of Things (IoT), wireless has attracted more and more attention as a means of connecting everything to the Internet.

  On the other hand, in a communication system for industrial equipment that requires high reliability, wireless is still shunned and wired is still popular. In the background of the lack of widespread use of wireless as a communication system for industrial equipment requiring high reliability, communication becomes impossible if the communication environment deteriorates due to surrounding weather conditions or if obstacles enter the propagation path between the transmission side and the reception side. It is an unstable system that does not guarantee that communication is always possible.

  In addition, as mobile Wi-Fi routers, smart phones with tethering functions, wirelessly-controlled drone drones, and the like have become widespread, the fact that their radio interference has deteriorated the communication environment and that they can be moved has led to the communication environment. This makes it difficult to grasp and predict wireless communication, which is a factor that hinders the spread of wireless communication in highly reliable applications. Further, there is a concern that radio interference may occur when jamming radio waves are intentionally transmitted.

  In order to solve these wireless problems, Japanese Patent Application Laid-Open No. H11-157572 discloses that a small airplane performs wireless relay between a base station and a plurality of mobile stations. The stable communication is realized by changing the position and route of the small flying object and changing the network configuration flexibly so that the distance from the relay station is equal to or less than a predetermined value. In addition, since the flying objects are located in the air, a propagation path without obstacles on the way can be secured, and attenuation of the signal intensity can be suppressed. Further, there is disclosed a method of performing continuous communication by substituting another small vehicle when a small vehicle fails.

  Patent Literature 2 discloses a method in which when communication demand is expected to increase rapidly due to seasonal fluctuations, sudden accidents, or the like, a flying relay station for assistance is appropriately arranged to ensure sufficient communication capacity without delay. . Further, a method is disclosed in which when communication by laser light is interrupted due to a failure in an optical communication function or the like and it is difficult to recapture, communication is switched to communication using radio waves to avoid interruption of communication.

  In Patent Document 3, position information and electric field strength of a ground station and an aerial node device are detected, position information and electric field strength are obtained by mutual communication, position information for enabling required communication is calculated, and a predetermined position is calculated. A method of replacing a network node damaged by, for example, a disaster occurring by moving is disclosed.

  According to Patent Document 4, when a communication failure occurs in a wireless mesh network, a reference value of a transfer traffic amount and a number of wireless links for each time zone in a normal time is statistically calculated, and based on the criterion, the maximum availability is determined. And prioritize the transmission paths and nodes with high reconfiguration. Furthermore, a method is disclosed in which, when a radio node fails, a mobile base station is dispatched to a position of a high-priority radio node based on the reference value, forms a radio link with a peripheral radio node, and functions as a relay node. ing.

JP-A-2004-336408 JP 2007-13513 A JP 2008-236438 A JP 2013-239827 A

  However, in the method of Patent Document 1, when weather conditions deteriorate or obstacles move on a radio propagation path, it is necessary to reduce the distance between the mobile station and the relay station. Since the distance between the mobile station and the relay station cannot be dynamically optimized only by changing the position of the squadron in response, there has been a problem that continuous communication cannot be performed. Further, there is no mechanism for predicting the failure of the small flying object, and there is a problem that it takes a long time to recover from the communication failure because an alternative small flying object moves after the failure of the small flying object.

  Although the method of Patent Document 2 can cope with a rapid increase in communication demand, the position of the relay station cannot be changed dynamically, so that continuous communication cannot be performed when the weather conditions deteriorate or when an obstacle moves to a wireless propagation path. There was a problem.

  In the method of Patent Document 3, when the radio wave environment changes rapidly, such as when the weather conditions deteriorate or an obstacle moves to a wireless propagation path, it takes time to find a position where the electric field strength reaches a predetermined state. As a result, there is a problem that continuous communication cannot be performed. Further, even if the electric field strength is high, there is a problem that if the interference wave is large, continuous communication cannot be performed.

  In the method of Patent Document 4, the destination of the mobile base station is determined based on the amount of transfer traffic and the number of wireless links, and the weather conditions of the destination are deteriorated, and there is an obstacle in the wireless propagation path at the destination. For example, when dispatched to an environment where the radio wave environment is poor, there is a problem that continuous communication cannot be performed. In addition, there is a problem that continuous communication cannot be performed, for example, when a mobile base station breaks down.

  The present application has been made in order to solve the above-described problems, and in a case where the radio wave environment is deteriorated, avoids the influence of the radio wave environment and increases the reliability of a wireless network between points where continuous communication is necessary. It is intended to obtain a wireless communication system.

  A wireless communication system according to the present application is a wireless communication system that performs communication via a wireless relay device that can move between wireless devices, wherein the wireless relay device monitors an obstacle that causes radio interference. Unit, an obstacle position specifying unit that specifies the position of the obstacle based on the output from the obstacle monitoring unit, an antenna unit that receives a desired wave and an interference wave to be received, and an interference wave based on an output from the antenna unit. An interference wave level detector for detecting the reception level of a desired wave, a desired wave level detector for detecting a reception level of a desired wave based on an output from the antenna unit, and an obstacle for monitoring the position of the obstacle and the reception level of the interference wave. An interference wave monitoring unit, a monitoring information unit that stores the position of the obstacle and the level of the interference wave, which are outputs from the obstacle interference wave monitoring unit, and an obstacle based on the position of the obstacle and the level of the interference wave. Occurs An interference interference wave identification unit for identifying whether the interference is present, an abnormality determination unit for determining whether the interference wave generated by the obstacle is at an abnormal level that impairs the wireless communication of the wireless relay device of the own device, and a wireless relay device of the own device A movable range information section that manages information on whether or not the apparatus can be moved for each location, and a wireless relay that is its own apparatus based on the information about whether or not the apparatus can move when the abnormality determination section determines that the level is abnormal. A position control unit that determines a destination of the device and controls a position of the wireless relay device that is the own device.

  According to the present application, when there is an obstacle that becomes a radio wave obstruction, the wireless relay device moves autonomously to a place with a good radio wave environment to specify the position of the obstruction and avoid the influence of the obstruction, By increasing the use efficiency of the spatial radio wave environment, it is possible to obtain a wireless communication system that can increase the reliability of a wireless network between high-priority wireless devices that need to perform continuous communication.

FIG. 2 is a configuration diagram of a wireless relay device used in the wireless communication system according to the first embodiment. FIG. 3 is a diagram illustrating a flowchart for identifying an obstacle that generates an interference wave in the wireless communication system according to the first embodiment. FIG. 5 is a diagram illustrating a flowchart for avoiding the influence of an obstacle that causes radio interference in the wireless communication system according to the first embodiment. FIG. 5 is a diagram illustrating an example of movement availability information for each coordinate managed by a movable range information unit in the wireless communication system according to the first embodiment. FIG. 3 is a diagram illustrating a flowchart for determining coordinates for limiting a destination in the wireless communication system according to the first embodiment; FIG. 4 is a conceptual diagram of avoiding an obstacle by a wireless relay device of the own device in the wireless communication system according to the first embodiment. FIG. 9 is a configuration diagram of a wireless relay device used in a wireless communication system according to a second embodiment. FIG. 13 is a diagram illustrating a flowchart for requesting rescue to a wireless relay device of another device in the wireless communication system according to the second embodiment. FIG. 13 is a conceptual diagram of requesting rescue to a wireless relay device of another device in the wireless communication system according to the second embodiment. FIG. 13 is a conceptual diagram of avoiding an obstacle by a wireless relay device of the own device and another device in the wireless communication system according to the third embodiment. FIG. 13 is a conceptual diagram of determining destination candidates of a wireless relay device of the own device and another device in the wireless communication system according to the third embodiment. FIG. 17 is a diagram illustrating a flowchart for determining a destination route of a wireless relay device of the own device and another device in the wireless communication system of the third embodiment. FIG. 15 is a conceptual diagram of avoiding an obstacle by a wireless relay device of the own device and another device in the wireless communication system according to the fourth embodiment. FIG. 17 is a diagram illustrating a flowchart for requesting rescue to a wireless relay device of another device in the wireless communication system according to the fourth embodiment. FIG. 17 is a conceptual diagram for warning an obstacle generating an interference wave in the wireless communication system according to the fifth embodiment.

Embodiment 1 FIG.
Hereinafter, the wireless communication system according to the first embodiment of the present application will be described with reference to FIGS.
A wireless communication system communicates, for example, with a wireless device at a position distant from each other via a wireless relay device in which the wireless device can move.
FIG. 1 is a configuration diagram of a wireless relay device used in the wireless communication system according to the first embodiment. When wireless communication is performed between wireless devices fixedly arranged at two points, for example, radio waves are transmitted. It is used as a mobile wireless relay device to increase the reliability of wireless networks between high-priority points that need to continue communication even when the environment deteriorates, and to avoid the effects of the deterioration of the radio wave environment. Things. The wireless relay device is mounted on an unmanned flying object such as a drone and can move in space.

In FIG. 1, the wireless relay device of the wireless communication system includes an obstacle monitoring unit 101, an obstacle position specifying unit 102, an antenna unit 103, an interference wave level detecting unit 104, a desired wave level detecting unit 105, It comprises an object interference wave monitoring unit 107, a monitoring information unit 108, an obstacle interference wave identification unit 109, an abnormality determination unit 110, a movable range information unit 111, and a local device position control unit 112.
The obstacle monitoring unit 101 monitors an obstacle such as a person or an object that causes radio interference, and a camera, a millimeter wave radar, an infrared sensor, a LiDAR, an ultrasonic range finder, and a camera for specifying the position of the obstacle. A specific GPS, an altitude sensor, or the like is used. The obstacle position specifying unit 102 specifies the position of the obstacle based on the output from the obstacle monitoring unit 101.

  The antenna unit 103 receives an interference wave generated from an obstacle or the like, and the interference wave level detection unit 104 detects the reception level of the interference wave. Further, the antenna unit 103 receives a desired wave to be received, and the desired wave level detection unit 105 detects the reception level of the desired wave. The obstacle interference wave monitoring unit 107 calculates the distance Di (position of the obstacle) between the wireless relay device as its own device and the obstacle calculated by the obstacle position identification unit 102 and the interference measured by the interference wave level detection unit 104. The wave level PNi is monitored, and the distance Di to the obstacle and the interference wave level PNi are stored in the monitoring information unit 108 in time series.

The obstacle interference wave identification unit 109 determines whether or not an interference wave is coming out of the obstacle. And the correlation between the interference wave. If there is a correlation, it is specified that an interference wave is being generated from the obstacle.
The correlation coefficient Cn is a coefficient calculated from the positional relationship of the obstacle and the level of the interference wave. The obstacle interference wave identification unit 109 stores the calculated correlation coefficient Cn in the monitoring information unit 108.

障害物が干渉波を発生していた場合、一般的に干渉波レベルＰＮｉは障害物との距離Ｄｉの二乗に反比例するため、相関が有る場合の相関係数は−１≦Ｃｎ＜０の間をとる。 Here, for example, the correlation coefficient Cn is represented by the following equation (1) using a general Pearson correlation coefficient equation.

When an obstacle generates an interference wave, the interference wave level PNi is generally inversely proportional to the square of the distance Di to the obstacle, so that the correlation coefficient when there is a correlation is between −1 ≦ Cn <0. Take.

  The abnormality determination unit 110 determines, based on the information from the obstacle interference wave identification unit 109 and the monitoring information unit 108, the interference wave generated by the obstacle detected by the interference wave level detection unit 104, It is determined whether or not the level is such that communication is inhibited. The determination method may be that an abnormal level is determined when the level of the interference wave exceeds a predetermined threshold, or the S / N ratio of the reception level of the desired wave and the reception level of the interference wave is monitored, and the S / N ratio exceeds the predetermined threshold. If it exceeds, it may be determined that the level is abnormal.

The movable range information unit 111 stores and manages whether or not the wireless relay device, which is its own device, may move at each three-dimensional location by storing moveability information.
The own device position control unit 112 determines the destination of the wireless relay device, which is the own device, based on the mobility information from the movable range information unit 111, and moves the position of the wireless relay device, which is the own device, to the destination. Control.

A method for specifying the position of an obstacle that generates an interference wave will be described with reference to the flowchart in FIG.
In FIG. 2, a step S1 calculates a correlation coefficient Cn by the obstacle interference wave identification unit 109, and the process proceeds to a step S2. In step S2, it is determined whether the correlation coefficient Cn is 0 or more. If there is a positive correlation in which the correlation coefficient Cn is 0 or more (No), there is no correlation between the obstacle and the interference wave. Then, it is determined that the obstacle does not generate an interference wave. Thereafter, the process proceeds to step S4, and after a lapse of a predetermined time Ta (Yes), the process returns to step S1 to calculate the correlation coefficient Cn again and determine again whether there is a correlation.

  In step S2, when there is a negative correlation with the correlation coefficient Cn being 0 or less (Yes), the process proceeds to step S5, and it is determined whether the correlation coefficient is not more than α. Here, α is a threshold value for determining that an obstacle generates an interference wave. If the correlation coefficient is α <Cn <0 in step S5 (No), the process proceeds to step S6, and it is determined that the correlation is weak. Thereafter, the process proceeds to step S7, and after a lapse of a predetermined time Tb (Yes), the process returns to step S1 to calculate the correlation coefficient Cn again and determine again whether there is a correlation.

  In step S5, when the correlation coefficient is Cn ≦ α (Yes), the process proceeds to step S8, where it is determined that there is a correlation, and it is determined that an obstacle generates an interference wave. Thereafter, the process proceeds to step S9, and after a lapse of a predetermined time Tc (Yes), the process returns to step S1 to calculate the correlation coefficient Cn and determine again whether there is a correlation. Here, the relationship between the predetermined times Ta, Tb, and Tc is, for example, Tc <Tb <Ta. When there are a plurality of obstacles, a correlation coefficient is obtained for each obstacle, and it is determined whether each obstacle generates an interference wave.

For the sake of simplicity, the correlation coefficient Cn is, for example, the difference between the interference wave level PNn and the interference wave level PNn + 1, the square of the distance Dn + 1 to the obstacle, and the obstacle, as shown in the following equation (2). The difference may be obtained from the quotient of the difference from the square of the distance Dn.
Cn = {(PNn) − (PNn + 1)} / {(Dn + 1) ² − (Dn) ² } (2)
Here, the level of the interference wave PNn + 1 at the time Tn + 1, the distance Dn + 1 to the obstacle, the level PNn of the interference wave at the time Tn, and the distance Dn to the obstacle are assumed. In order to eliminate temporary steep fluctuations and errors due to fading, an equalizer may be used or averaging may be performed.

Further, as shown in the following equation (3), the correlation coefficient Cn is a quotient of the product of the interference wave levels PNn + 1 and PNn at the time Tn + 1 and the time Tn and the square of the distance Dn + 1 and Dn from the obstacle. You may ask.
Cn = {(PNn + 1) * (Dn + 1) ² } / {(PNn) * (Dn) ² } (3)
Since the correlation coefficient Cn is a coefficient calculated from the positional relationship of the obstacle and the level of the interference wave, a calculation method other than the above equation may be used.

A method of avoiding an obstacle that generates an interference wave will be described with reference to the flowchart in FIG. 3 and a conceptual diagram of the movable range information unit 111 in FIG.
In FIG. 3, in step S11, the obstacle monitoring unit 101 detects whether or not an obstacle has moved. If there is a movement of the obstacle in step S11 (Yes), in step S12 the obstacle position specifying unit 102 specifies the position of the obstacle.

In the movable range information unit 111, information on whether or not the own device can move for each location, for example, as shown in FIG. 4, such as [obstacle <presence / absence>, movement <presence / absence>, the order of the destination candidate <i (i = enter numbers of up to 1~n ^3)>, which manages the interference wave generation <Yes / No>].
The movement availability information is managed by, for example, three-dimensional coordinate axes (Xi, Yi, Zi), i = 1 to n, and indicates the position (Source Coorinate) of the wireless relay device 200-1 which is its own device before the movement. (Xsc, Ysc, Zsc), the moved position of the obstacle _{230 (Xa, Y 1, Zc} ), the position of the wireless relay device 200-2 is self apparatus after moving the (Destination Coordinate) (Xdc, Ydc , Zdc).

In step S13 subsequent to step S12, the position of the obstacle is mapped in the movable range information unit 111 based on the information from the obstacle position specifying unit 102 and the abnormality determination unit 110 in the own device position control unit 112. I do. Here, the mapping refers to the movement availability information of the position (Xa, Y ₁ , Zc) at which the obstacle has been moved acquired by the obstacle position identification unit 102 [obstacle <presence / absence>, movement <presence / absence> , the order of the destination candidate <i (numbers of up to i = 1~n ³ enters)>, refers to update the interference wave generation <Yes / No>].
The movement availability information at the position (Xa, Y ₁ , Zc) where the obstacle has moved indicates that the obstacle <None>, the movement <OK>, and the order of the destination candidate <i (i = entering a unique number between 1 to n ^3)>, that interference occurred was <No>, after which the obstacle has moved, [obstacle <Reed> mobile <No>, the moving destination candidate The order is <-(blank)>, and the interference wave is generated <Yes>].

In step S14, the obstacle interference wave identification unit 109 checks whether there is an obstacle whose identification of the obstacle and the interference wave has been completed. If there is an obstacle whose identification has been completed (Yes), the flow proceeds to step S15. Then, the movement availability information of the position where the obstacle exists in the movable range information unit 111 is updated.
Until the identification by the obstacle interference wave identification unit 109 is completed, the obstacle availability information at the position (Xa, Y ₁ , Zc) at which the obstacle has moved is “obstacle <Yes>, movement <No>, destination The candidate order <-(blank)> and interference wave generation <absent>, but when the identification is completed, the order of the obstacle <presence>, move <impossible>, move destination candidate <-(move) Synonymous with no preceding)>, interference wave generation <Yes>].

  Here, when the movement prohibited area is known in advance by three-dimensional map information or the like, the movable range information unit 111 corresponds to the movement prohibited area based on obstacle information of the three-dimensional map information. The coordinates may be set in advance as [obstruction <presence>, movement <impossible>, destination candidate order <-(blank)>, interference wave generation <-(blank)>].

Next, in the abnormality determination unit 110,

In step S16, when the SN ratio obtained by the abnormality determination unit 110 is lower than the predetermined threshold β (Yes), the abnormality level is determined, and the process proceeds to step S17. The movement permission information of the unit 111 is updated. Coordinates to update the movement permission information, the own device position control unit 112, the position (Xa, _{Y 1} position of the radio relay device is a self-device (Xsc, Ysc, Zsc) and interference wave sources (obstacle) , Zc), the communication deteriorates due to the interference wave, so that the movement availability information is forcibly updated collectively to move <impossible> (the order of the destination candidates is also performed simultaneously <−>). Restrict destinations.

A method of determining coordinates for limiting the destination will be described with reference to the flowchart of FIG. The determination of the area of the coordinates that limits the movement destination is performed, for example, by sequentially monitoring the fluctuation of the interference wave level or the SN ratio in accordance with the movement of the wireless relay device or the obstacle that is the own device, and determining the directivity of the radio wave of the interference wave. Is performed by predicting
In FIG. 5, in step S21, it is determined whether or not the wireless relay device that is its own device has moved, and if there has been movement (Yes), the process proceeds to step S22, where the SN ratio of the previous value and the SN ratio of the current value are determined. Is compared. In step S22, if the SN ratio of the current value is lower than the SN ratio of the previous value (No), the process proceeds to step S23, and the area for limiting the movement destination of the wireless relay device, which is its own device, is enlarged according to the moving direction. Let it.
For example, when moving from (Xsc, Ysc, Zsc) to (Xsc + 1, Ysc + 1, Zsc), and when the SN ratio becomes lower than the previous value, the position (Xsc + 1, Ysc + 1, Zsc) of the wireless relay device that is its own device The area for limiting the movement destination between the object and the obstacle (Xa, Y ₁ , Zc) is enlarged in the X direction and the Y direction by +1 minute, or by an amount multiplied by a ratio corresponding to the change in the SN ratio.

  In step S18 of FIG. 3, when the abnormality determination unit 110 determines that there is an abnormality, the own device position control unit 112 searches the movable range information unit 111 for the coordinates of the movement <OK>, or selects a destination candidate. It is searched whether there are coordinates to which the order is assigned. If there is a destination (Yes), the process proceeds to step S19 to move to the destination. Here, if the SN ratio does not improve when moving to the destination, the destination is autonomously reviewed according to the order of the destination candidates. Thereafter, the process proceeds to step S20, and after a predetermined time Td has elapsed (Yes), the process returns to step S11.

Here, when the obstacle itself that generates the interference wave also moves, as in the case where the wireless relay device that is its own device moves, it moves to the destination according to the positional relationship between the obstacle and the wireless relay device that is its own device. Update the area to restrict. When the obstacle moves away, the restricted area is reduced according to the distance moved and the improvement of the SN ratio.
The S / N ratio, which is a judgment value for judging an abnormality by the anomaly judgment unit 110, and the S / N ratio measured to restrict a destination when an obstacle generates an interfering wave are determined by the Shannon-Hartley theorem. It can be an expression. Further, the determination value by the abnormality determination unit 110 may be determined simply by the level of the interference wave, and the destination may be limited, instead of the SN ratio.

When the distance between the wireless relay device, which is its own device, and the obstacle is calculated by the monitoring information unit 108 described above, the distance may be obtained from the coordinates of the movable range information unit 111.
Further, since it is conceivable that the obstacle may move sequentially, the coordinates for restricting the movement destination may be appropriately determined based on the coordinates of the obstacle estimated using a Kalman filter or the like, and the movement availability information may be appropriately updated. Absent.

In addition, the candidate location of the movement destination of the wireless relay device, which is its own device, is coordinated with the radio wave environment (for example, the SN ratio or the level of the desired wave) in the movable range in advance or in a time zone where communication is not required. The radio wave environment (for example, the SN ratio or the level of a desired wave) that changes with the movement of the wireless relay device, which is its own device, may be determined for each coordinate. It is also possible to autonomously learn a location that is equal to or greater than a predetermined threshold, and autonomously set a location having a large number of coordinates that are equal to or greater than the threshold as a candidate location for a movement destination.
In addition, even when there are a plurality of obstacles, the position of the obstacle generating the interference wave is identified by identifying each obstacle by the method of FIGS. 2, 3, and 4.

  FIG. 6 is an example of a conceptual diagram for avoiding the influence of an obstacle in the wireless communication system according to the first embodiment. When the obstacle 230 approaches, the wireless relay device 200-1 (generally referred to as 200), which is a device that relays wireless communication between the wireless device 210 and the wireless device 220 whose positions are fixed, In order to identify the position of the obstacle 230 generating the interference wave by the method described in FIGS. 1, 2 and 3 and avoid the influence of the interference wave, the method described in FIGS. 3, 4 and 5 is used. Then, an optimal destination is found in the movable range 250, and the position of the wireless relay device 200-1 (broken line) is moved to the position of the wireless relay device 200-2 (solid line).

As described above, the position of the wireless relay device 200, which is its own device, can be spatially controlled so as to avoid the influence of the interference wave in accordance with the position of the obstacle 230 that generates the interference wave. Continuous communication can be stably performed between the device 210 and the wireless device 220. Further, with the movement of the position of the wireless relay device 200 as its own device or the position of the obstacle 230 that generates an interference wave, the candidate value of the destination of the wireless relay device 200 can be sequentially reviewed. It can respond to changes and maintain a stable radio communication environment.
Further, since it is determined whether or not the interference wave is at a level that hinders wireless communication, even when an obstacle that does not generate an interference wave approaches, the position of the wireless relay device 200, which is its own device, is adjusted to the optimum radio wave environment. Since it can be moved to a position, a stable radio communication environment can be maintained.

  According to the first embodiment of the present application, even if an obstacle 230 such as a person or an object that causes radio interference moves, the radio network between the points with high priority is autonomously operated in a timely manner so as to continuously operate. The position of the object 230 is specified, the influence of the obstacle is monitored, and the wireless relay device 200 autonomously moves to a place having a good radio wave environment so as to avoid the influence of the obstacle, and uses the spatial radio wave environment. By increasing the efficiency, a wireless communication system that can increase the reliability of the wireless network between the high-priority wireless devices 210 and 220 that need to perform continuous communication can be obtained. As a result, it is possible to significantly reduce the installation work time of the wireless relay device 200 and to reduce the installation work cost, eliminating the need for manual maintenance by a network administrator and improving maintainability.

Embodiment 2 FIG.
Next, a wireless communication system according to Embodiment 2 of the present application will be described with reference to FIGS.
In the second embodiment, the priority of the communication that needs to be continuously communicated using another wireless relay device 201 (hereinafter, a wireless relay device of another device) without moving the position of the wireless relay device 200 that is its own device. It is intended to improve the reliability of a wireless network between high points.
The method for specifying the obstacle generating the interference wave and the method for specifying the candidate destination of the movement are the same as those in the first embodiment, and the description is omitted.

FIG. 7 is a configuration diagram for requesting rescue to a wireless relay device of another device of the wireless communication system according to the second embodiment. The configuration other than the addition of the other device rescue request determination unit 113 and the other device rescue request unit 114 is the same as that of the embodiment. The configuration is the same as that of the first embodiment shown in FIG. 1, and the drawing is omitted.
In FIG. 7, the abnormality determination unit 110 monitors the S / N ratio in the same manner as in the first embodiment, so that the interference wave generated by the obstacle 230 detected by the interference wave level detection unit 104 is transmitted to the own device. Is determined to be a level that hinders wireless communication of the wireless relay device 200. The other device rescue request determining unit 113 is the same as the first embodiment when the abnormality determining unit 110 determines that the level is abnormal, or when the abnormal determination unit of the other device rescue request determining unit 113 determines that the level is abnormal. The movable range information unit 111 is updated by the method described above, and when the movable range information unit 111 has a destination of the wireless relay device 201 of another device, a request for rescue is made to the other device rescue requesting unit 114.

  FIG. 8 is a diagram showing a flowchart for requesting rescue to the wireless relay device 201 of another device in the wireless communication system according to the second embodiment. In FIG. 8, in step S31, the other device rescue request determination unit 113 determines whether the SN ratio obtained by the abnormality determination unit 110 is equal to or less than a predetermined threshold value β, or the abnormality determination of the other device rescue request determination unit 113 itself. If the SN ratio falls below the predetermined threshold value γ in the section (Yes), it is determined that there is an abnormality, and the process proceeds to step S32. In step S32, the own device position control unit 112 updates the movement availability information of the movable range information unit 111 in the same manner as in the first embodiment. In step S33, it is determined whether or not there is a destination of the wireless relay apparatus 201 of another device in the movable range information unit 111. If there is a destination (Yes), the process proceeds to step S34, and the other device rescue requesting unit 114 Request for rescue of the wireless relay device 201 of the other device.

  On the other hand, if it is determined in step S31 that the abnormality determination unit 110 has not determined that there is an abnormality, or if the SN ratio is equal to or greater than the predetermined threshold γ of the other device rescue request determination unit 113 itself (No), the process proceeds to step S35. The other device rescue request determination unit 113 instructs the other device to cancel the rescue request to the wireless relay device 201 and return the other device's wireless relay device 201 to its original location.

  Here, the candidate location to which the wireless relay device 201 of the other device has moved may be notified from the wireless relay device 200 of the own device, or the wireless relay device 201 of the other device may be notified by itself as described in the first embodiment. The determination may be made in the same manner as the wireless relay device 200 of the own device, or may be a wireless relay device different from the wireless relay device 201 of the other device. In order to avoid the influence of interference when the wireless relay device of the own device and the wireless relay device of another device are close to each other, a method of selecting an optimal wireless system or a wireless frequency by using a technology such as cognitive wireless may be used together. I do not care. Further, the abnormality determination unit 110 monitors the state of the wireless relay device 200 of the own device such as failure prediction information (reduction of transmission output, deterioration of reception sensitivity, etc.) of the wireless relay device 200 of the own device. May be determined and a rescue request may be made to the wireless relay device 201 of another device.

  FIG. 9 is an example of a conceptual diagram for avoiding the influence of an obstacle in the wireless communication system according to the second embodiment. When the obstacle 230 approaches, the wireless relay device 200 that relays the wireless communication between the wireless device 210 and the wireless device 220 generates an interference wave by the method described with reference to FIGS. 1, 2, and 3. In order to identify the position of the obstacle 230 and avoid the influence of the interference wave, the optimum destination within the movable range 250 is found by the method described with reference to FIGS. In the method shown in FIG. 8, a rescue request is made to the wireless relay device 201, which is another device, and the wireless relay device 201 is moved.

In this way, when the obstacle 230 that generates the interference wave approaches the wireless relay device 200 between the wireless devices 210 and 220 having the higher priority for continuous communication, the obstacle 230 is another device to avoid the influence of the interference wave. Requests rescue from the wireless relay device 201, moves to a position where an optimal radio wave environment can be obtained, and performs wireless relay by the wireless relay device 201 of another device, thereby realizing continuous communication of the network between points with high priority. I do.
Further, since the radio wave abnormality can be detected based on the SN ratio, even when an obstacle that does not generate an interference wave approaches, the wireless relay device 201 of another device can be moved to the position of the optimum radio wave environment, so that a stable radio communication environment can be obtained. Can be maintained.
With such a highly reliable wireless communication system, even in a place where a large number of wireless devices cannot be arranged (depopulated area or outer space), a highly reliable wireless network can be constructed with a minimum necessary number. Cost can be reduced.

Embodiment 3 FIG.
Next, a wireless communication system according to Embodiment 3 of the present application will be described with reference to FIGS.
In the third embodiment, by moving the positions of the wireless relay devices 200 and 201 between the own device and the other device, and using both the own device and the other device as the wireless relay device, a high-priority point where continuous communication is necessary is required. It is intended to improve the reliability of a wireless network between them.
The configuration of the wireless communication system according to the third embodiment is the same as that of FIG. 7 of the second embodiment, and the drawing is omitted. The method for identifying an obstacle generating an interference wave, the method for determining an abnormality, and the method for requesting rescue are the same as those in the first and second embodiments, and a description thereof will be omitted. Here, a method of determining the optimal destination in the radio wave environment of a plurality of devices will be described.

  FIG. 10 is an example of a conceptual diagram for avoiding the influence of an obstacle in the wireless communication system according to the third embodiment. In FIG. 10, when the obstacle 230 approaches, the wireless relay device 200-1 of the own device that relays the wireless communication between the wireless device 210 and the wireless device 220 uses the method described with reference to FIGS. 1, 2, and 3. In order to identify the position of the obstacle generating the interference wave and avoid the influence of the interference wave, the movable range 251 of the wireless relay device 200 of the own device can be determined by the method described with reference to FIGS. Find the best destination in On the other hand, a rescue request is made to the wireless relay device 201 of another device by the method shown in FIGS. 7 and 8, and an optimal destination is found in the movable range 252 of the wireless relay device 201 of another device. The destinations of the wireless relay device 200 of its own device and the wireless relay device 201 of another device are determined by the method shown in FIG. 11 and are moved.

FIG. 11 is a conceptual diagram of using the movable range information unit 111 to determine destination candidates for the wireless relay device 200 of the own device and the wireless relay device 201 of another device. The coordinates of the wireless device 210 are shown at 211, and the coordinates of the wireless device 220 are shown at 221.
The wireless relay device 200 of the own device and the wireless relay device 201 of the other device need to be arranged at spatial positions having the best radio wave environment in the space between the wireless device 210 and the wireless device 220. Although the propagation paths of the radio waves of the wireless device 210 and the wireless device 220 exist innumerably as shown by, for example, R1, R2, R3, R4, and R5, it is difficult to select the optimum propagation route from all the propagation routes. Therefore, the number of candidate propagation paths is reduced, and a propagation path is selected from among them.

FIG. 12 is a flowchart for determining a destination route of the wireless relay device 200 of the own device and the wireless relay device 201 of another device in the wireless communication system. A method of selecting a propagation route will be described based on the flowchart.
In FIG. 12, in step S41, the number of candidate propagation paths is reduced to select an optimal propagation path from all the propagation paths, and a propagation path is selected from among them. Here, for example, R1, R2, R3, R4, and R5 are defined as propagation paths. In order to efficiently select the optimal propagation path, each of the propagation paths R1 to R5 is a path that is not spatially biased. In step S <b> 42, the own device position control unit 112 totals the number of unmovable coordinates in the moveability information of the movable range information unit 111 for each of the propagation paths R <b> 1 to R <b> 5.

A step S43 selects, from the propagation paths R1 to R5, a path in which the number of immovable parts has the minimum value. A step S44 decides whether or not there is a route of which the number of immovable objects is the minimum value of 0. If the minimum value is 0 (Yes), the process proceeds to the step S45 to determine a route. In step S44, if there is no route with the minimum value of 0 (No), the process proceeds to step S46, and it is determined whether or not there is a route having the minimum value among routes without obstacles. In Step S46, when there is a route having the minimum value (Yes), the process proceeds to Step S47, and the route is determined. In step S46, when there is no route without any obstacle (No), the process proceeds to step S48 to review the route, and returns to step S41 to determine the route again by the same flow.
As shown in the route determination example of FIG. 11, the propagation route R5 in which the number of unmovable coordinates is the minimum value “1” and the number of faulty coordinates is “0” is selected.

  Here, when there are a plurality of minimum routes without obstacles (hereinafter referred to as candidate routes), for example, a route that is farthest from the obstacle is selected as a propagation route, or a spatially middle one among the candidate routes. The propagation path in is predicted to have the best radio wave environment and is selected. If the optimal route cannot be selected from among the candidate routes, or if the user is not sure, the number of propagation routes to be investigated is increased by selecting a route near the candidate route where the optimal propagation route is likely to exist. Alternatively, a propagation path that is most centrally located may be selected.

  When the propagation route is determined, as shown in FIG. 11, for example, two intermediate points 290 and 291 which are equal to the length of the path between the wireless relay device 200 of the own device and the wireless relay device 201 of the other device are equally divided into three. Is selected as the destination of the wireless relay device 200 of the own device and the wireless relay device 201 of the other device. Whether the destination of the wireless relay device 200 of the own device or the wireless relay device 201 of the other device is the location 290 or 291 is determined by the wireless relay device 200 of the own device, for example, the location 290 first. For example, the destination of the location 291 is notified to the wireless relay device 201 of the above.

Here, a method of improving the reliability of the wireless network with two wireless relay devices, one each of the wireless relay device 200 of the own device and the wireless relay device 201 of the other device, has been described. The number of devices may be two or more.
In this way, when an obstacle generating an interference wave approaches a wireless network between high-priority points for continuous communication, in order to avoid the influence of the interference wave, the wireless communication between the own device and another device is autonomously performed. By moving the position of the relay device to a position where an optimal radio wave environment is obtained and performing wireless relay between the wireless relay device of the own device and the wireless relay device of another device, continuous communication of the network between points with high priority is realized.
Furthermore, since radio wave abnormalities can be detected based on the SN ratio, even if an obstacle that does not generate an interference wave approaches, the wireless relay device of another device can be moved to the position of the optimum radio wave environment. It can be maintained.

Embodiment 4 FIG.
Next, a wireless communication system according to Embodiment 4 of the present application will be described with reference to FIGS.
In the fourth embodiment, the reliability of the wireless network between high-priority points that need to be continuously communicated is increased even when there is a lot of moisture or rain such as in the rainy season, which causes radio interference.
The wireless communication system according to the fourth embodiment includes a humidity sensor 271 in the wireless relay device 200, which is its own device, as shown in FIG. The abnormality determination unit 110 monitors the humidity by the humidity sensor 271 as appropriate. Other configurations are the same as those in FIG. 7 of the second embodiment, and the drawings are omitted.
The method for determining radio wave abnormality, the method for requesting rescue to a wireless relay device of another device, and the method for determining the optimal destination of a plurality of wireless relay devices are the same as those in the first, second, and third embodiments. Is omitted. Here, a method of determining a destination of a plurality of wireless relay devices will be described.

FIG. 13 is an example of a conceptual diagram for avoiding the influence of an obstacle in the wireless communication system according to the fourth embodiment.
In FIG. 13, when the obstacle 231 approaches, the wireless relay device 200-1 of the own device that relays the wireless communication between the wireless device 210 and the wireless device 220 uses the method described with reference to FIGS. 1, 2, and 3. In order to identify the position of the obstacle generating the interference wave and avoid the influence of the interference wave, the movable range 251 of the wireless relay device 200 of the own device can be determined by the method described with reference to FIGS. Find the best destination in On the other hand, a rescue request is made to the wireless relay device 201 of another device by the method shown in FIGS. 7 and 8, and an optimal destination is found in the movable range 252 of the wireless relay device 201 of another device. The destinations of the wireless relay device 200 of its own device and the wireless relay device 201 of another device are determined by the methods shown in FIGS.

FIG. 14 is a diagram illustrating a flowchart for requesting rescue to the wireless relay device 201 of another device in the wireless communication system according to the fourth embodiment.
In FIG. 14, in step S51, the abnormality determination unit 110 determines whether the humidity in the environment of the wireless network is abnormal. If it is determined that the humidity is abnormal at or above the predetermined threshold value RHα (Yes), the process proceeds to step S52, and the other device rescue request determination unit 113 updates the movable range information unit 111 in the same manner as in the second embodiment. I do. A step S53 decides whether or not the movable range information section 111 has a destination of the wireless relay device 200 of its own device and the wireless relay device 201 of the other device. If there is a destination (Yes), the process proceeds to a step S54. Proceeding to the movable range information unit 111, a rescue request is sent to the wireless relay device 201 of another device.

  In step S51, when the abnormality is not determined by the abnormality determination unit 110, or when the humidity is equal to or less than the predetermined threshold RHα in the abnormality determination unit of the other device rescue request determination unit 113 itself (No), the process proceeds to step S55. Then, the other device rescue request determination unit 113 instructs the other device to cancel the rescue request to the wireless relay device 201 and return to the location based on the wireless relay device 201 of the other device.

  Here, the humidity may be managed for each coordinate as a part of the parameter of the mobility information managed by the movable range information unit 111, and may be used as a parameter when determining an optimal propagation path. By using humidity as a parameter and using the method described in the first to third embodiments, the wireless relay device 200 of the own device can be moved to a position with low humidity.

In this way, even when there is a lot of humidity or rain such as in the rainy season, which causes radio interference, the position of the wireless relay device 200 of the own device is moved by monitoring the humidity to avoid the influence of the humidity, Requesting rescue from the wireless relay device 201 of another device, moving the wireless relay device 201 to a position where an optimal radio wave environment is obtained, and performing wireless relay by the wireless relay device 201 of the other device, thereby forming a high priority network between points. To achieve continuous communication.
Furthermore, by using the humidity as a parameter, the wireless relay device can be moved to a position with low humidity, so that the influence of the life degradation due to humidity can be reduced, and the life of the wireless relay device can be extended. The effect is also obtained.

Embodiment 5 FIG.
Next, a wireless communication system according to Embodiment 5 of the present application will be described with reference to FIG.
In the fifth embodiment, the reliability of a wireless network between high-priority points where continuous communication is required is improved even when an interference wave generated by an obstacle is large and relaying by the wireless relay device of the own device is difficult. It is like that.
In the wireless communication system according to the fifth embodiment, as shown in FIG. 15, the wireless relay device 200 of the wireless communication device includes a warning device 281 that warns of an obstacle that generates an interference wave. Other configurations are the same as those in FIG. 7 of the second embodiment, and the drawings are omitted.

A method of identifying an obstacle generating an interference wave, a method of determining a radio wave abnormality, a method of requesting rescue to a wireless relay device of another device, and a method of determining an optimal destination of a plurality of wireless relay devices are: The description is omitted because it is the same as in the first, second, and third embodiments. Here, a method for warning an obstacle in which an interference wave is generated so as not to generate the interference wave will be described.
The obstacle 230 that generates the interference wave is identified by the same method as in the first embodiment, the wireless relay apparatus 200 of the own apparatus moves to the position of the obstacle 230, and the obstacle 230 is Warn against. On the other hand, a rescue request for the wireless relay device 201 of another device is made in the same manner as in the second embodiment, and continuous communication is performed between the wireless device 210 and the wireless device 220 using the wireless relay device 201 of the other device.

In this way, a warning is given to the obstacle 230 that generates an interference wave, a request is made to the wireless relay device 201 of another device for rescue, and the wireless relay device 201 of the other device is moved to a position where an optimal radio wave environment is obtained. By performing wireless relay according to, continuous communication of a network between points having high priority is realized.
When an interference wave such as an object, a person, an illegal radio wave, a leaked radio wave caused by a construction defect, or a jamming radio wave that causes radio interference is detected as moving into a wireless network between high-priority points, the radio wave is interrupted. By specifying the position of an object, a person, or the like, moving to that position, and issuing a warning, it is possible to maintain a stable and highly reliable wireless communication network.

  Above, we explained about the deterioration of the radio wave environment due to objects and people around the wireless relay device, and the climate such as humidity affecting the radio wave environment. Depending on the location restrictions such as the prohibited area, and the state of failure prediction information (reduction in transmission output, reception sensitivity, etc.) of the wireless relay device of the own device, the wireless relay device is autonomously searched for the optimum position. The movement or the number of wireless relay devices may be increased or decreased.

Although this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments may differ from those of the specific embodiments. The present invention is not limited to the application, and can be applied to the embodiment alone or in various combinations.
Accordingly, innumerable modifications not illustrated are envisioned within the scope of the technology disclosed herein. For example, a case where at least one component is deformed, added or omitted, and a case where at least one component is extracted and combined with components of other embodiments are included.

101: obstacle monitoring unit, 102: obstacle position specifying unit, 103: antenna unit
104: interference wave level detection unit, 105: desired wave level detection unit, 107: obstacle monitoring unit
108: monitoring information section, 109: obstacle interference wave identification section, 110: abnormality determination section
111: movable range information section, 112: own apparatus position control section,
113: Other device rescue request determination unit, 114: Other device rescue request unit,
200, 200-1, 200-2: wireless relay device of own device,
201: wireless relay device of another device, 210: wireless device, 220: wireless device,
230, 231: obstacle, 250, 251, 252: movable range,
271: Humidity sensor, 281: Warning device.

Claims (25)

  In a wireless communication system that performs communication via a wireless relay device that is movable between wireless devices, the wireless relay device includes an obstacle monitoring unit that monitors an obstacle that causes radio interference, and the obstacle monitoring unit. An obstacle position specifying unit that specifies the position of the obstacle based on the output from the unit, an antenna unit that receives a desired wave and an interference wave to be received, and a reception level of the interference wave based on an output from the antenna unit. An interference wave level detection unit for detecting, a desired wave level detection unit for detecting a reception level of the desired wave based on an output from the antenna unit, and an obstacle for monitoring a position of the obstacle and a reception level of the interference wave An interference wave monitoring unit, a monitoring information unit that stores the position of the obstacle and the level of the interference wave, which are outputs from the obstacle interference wave monitoring unit, and the position of the obstacle and the level of the interference wave. An obstacle interference wave identification unit that specifies whether an interference wave is being generated, and an abnormality determination that determines whether the interference wave generated by the obstacle is an abnormal level that impedes wireless communication of the wireless relay device that is its own device. Unit, a movable range information unit that manages the moveability information indicating for each location whether or not the wireless relay device that is the own device may move, and when the abnormality determination unit determines an abnormal level, Wireless communication comprising: determining a destination of the wireless relay device, which is the own device, based on the movement availability information; and controlling the position of the wireless relay device, which is the own device. system.   The wireless communication system according to claim 1, wherein the obstacle interference wave monitoring unit monitors a distance between the wireless relay device, which is the own device, and the obstacle.   The obstacle interference wave identification unit determines the correlation between the obstacle and the interference wave from the change in the distance between the wireless relay device and the obstacle, which is the own device, and the change in the level of the interference wave, The wireless communication system according to claim 1, wherein when there is a correlation, it is specified that the interference wave is generated from the obstacle.   4. The monitoring information unit according to claim 1, wherein a distance between the wireless relay device as the own device and the obstacle and a level of the interference wave are stored in time series. 5. 2. The wireless communication system according to claim 1.   5. The apparatus according to claim 1, wherein the abnormality determining unit monitors a level of the interference wave and determines that the level is abnormal when the level of the interference wave exceeds a predetermined threshold. 6. Item 14. The wireless communication system according to Item 1.   The said abnormality determination part monitors the SN ratio of the reception level of the said desired wave and the said interference wave, and when the said SN ratio exceeds a predetermined threshold value, it determines with an abnormal level. Item 5. The wireless communication system according to any one of items 4.   The wireless communication system according to any one of claims 1 to 6, wherein the movable range information section stores travel availability information indicating whether travel is possible for each three-dimensional location.   The moveability information stored in the movable range information unit includes, in addition to the moveability, presence / absence of the obstacle, presence / absence of an interference wave indicating whether the obstacle is generating an interference wave, 8. The wireless communication system according to claim 7, wherein the order of destination candidates indicating the priority order of destination candidates of a certain wireless relay device and the S / N ratio examined in the past are stored.   The wireless communication system according to claim 7, wherein the movable range information unit does not allow a location corresponding to a prohibited area to move from three-dimensional map information.   The device according to claim 1, wherein the own device position control unit updates the moveability information of the movable range information unit each time the wireless relay device or the obstacle that is the own device moves. The wireless communication system according to any one of Claims 9 to 10.   The apparatus according to claim 1, wherein the own apparatus position control unit updates the information about whether or not the section between the obstacle and the wireless relay apparatus as the own apparatus can be moved in a lump, and restricts a destination. The wireless communication system according to any one of claims 1 to 9.   The own device position control unit estimates the directivity of the interference wave from the level of the interference wave or the amount of change in the SN ratio with the movement of the wireless relay device, which is the own device, and determines whether the wireless relay device is the own device. The wireless communication system according to any one of claims 1 to 11, wherein a range in which a destination of the relay device is restricted is determined from the directivity of the interference wave.   The abnormality determination unit monitors the SN ratio of the reception level of the desired wave and the interference wave for each location, and the own device position control unit sets a location having an SN ratio equal to or greater than a predetermined value as a destination candidate location. The wireless communication system according to claim 1.   The wireless relay device that is the own device includes a humidity sensor, and the abnormality determination unit moves the position of the wireless relay device of the own device when the humidity is determined to be equal to or higher than a predetermined humidity. The wireless communication system according to claim 13.   The wireless relay device that is the own device is another device rescue request determination unit that determines whether to make a rescue request to the wireless relay device of the other device, and determines whether the wireless relay device of the other device can move. A moveable range information unit that manages the moveability information shown for each, determines a destination of the wireless relay device of the other device based on the moveability information, and the destination information to the wireless relay device of the other device. The wireless communication system according to claim 1, further comprising a rescue requesting unit for requesting rescue.   The other device rescue request determination unit, when the abnormality determination unit determines an abnormal level, or when the interference wave generated by the obstacle is determined to be an abnormal level possessed by the other device rescue request determination unit itself, The wireless communication system according to claim 15, wherein the other device rescue requesting unit requests the wireless relay device of the other device for rescue.   The wireless relay device as the own device cancels the rescue request to the wireless relay device of the other device when it is no longer necessary to request the wireless relay device of the other device for help. A wireless communication system as described.   The wireless relay device that is the own device may move the other device rescue request determination unit that determines whether to make a rescue request to the wireless relay device of another device, and the wireless relay device of the own device and the other device may move. A movable range information unit that manages mobility information indicating a location or location for each location, and determines a destination of the wireless relay device of the own device and the other device based on the mobility information, and determines a wireless destination of the own device. The device according to claim 1, further comprising: a position control unit for controlling the position of the relay device, and a rescue requesting unit for requesting rescue information and destination information to the wireless relay device of the other device. Wireless communication system.   When determining the destination of the wireless relay device of the own device and the other device, the own device position control unit selects a propagation path of a radio wave to be investigated so as not to be spatially biased, and moves for each of the propagation routes. 19. The method according to claim 18, further comprising: summing up the number of improper devices, selecting a route that minimizes the number of immovable devices, and determining a destination of the wireless relay device of the own device and the other device on the selected route. A wireless communication system according to claim 1.   20. The wireless communication system according to claim 19, wherein the own device position control unit selects a path with the least obstacle when selecting a propagation path of the radio wave.   20. The apparatus according to claim 19, wherein, when selecting the propagation path of the radio wave, the own apparatus position control unit sums up the S / N ratios that have been investigated in the past for each propagation path, and selects the path having the highest S / N ratio. A wireless communication system as described.   20. The local device position control unit according to claim 19, wherein, when there are a plurality of radio wave propagation routes and the candidates cannot be narrowed down, a spatially middle route is selected from the candidates. Wireless communication system.   The own device position control unit, when reviewing the propagation path to be searched, selects a space that is likely to be a candidate for the propagation path, redistributes the space, and re-examines to search for an optimal propagation path. The wireless communication system according to claim 19, wherein:   16. The wireless relay device, which is the own device, includes a humidity sensor, and when the abnormality determination unit determines that the humidity is equal to or higher than a predetermined humidity, requests a rescue request to the wireless relay device of the other device. Or the wireless communication system according to claim 18.   The abnormality determination unit is configured to perform the abnormality detection when the level of the interference wave exceeds a predetermined threshold or when the SN ratio of the reception level of the desired wave and the reception level of the interference wave exceeds a predetermined threshold. 19. The wireless communication device according to claim 15, wherein the rescue requesting unit requests rescue to the wireless relay device of the other device, and the wireless relay device of the own device issues a warning when approaching the obstacle. Communications system.

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