Propagation environment estimation method, propagation environment estimation system, and propagation environment estimation device

Abstract

The present disclosure relates to a propagation environment estimating method for estimating a propagation environment of radio waves by use of a scale model. This method comprises the following steps. A scale model is created (Step 11). A light source 10 simulating a radio wave transmitting station is installed in the scale model, the light source 10 being capable of emitting directional light and scanning in an irradiation direction (Step 12). The interior of the scale model is scanned with the light source 10, and, during the scanning, a center-light generation state is detected in which center light directed toward a point on a measurement straight-line passing through a measurement point set in the interior of the scale model is generated. A reception cylinder 18 is installed with the center line thereof aligned with the measurement straight-line (Step 13). A direction connecting the position of an irradiation point appearing on the reception cylinder 18 and the position of the measurement point in the center-light generation state is estimated as the incoming direction of the light that reaches the measurement point (Step 14).

Description

[Technical Field]

[0001] The present disclosure relates to a propagation environment estimation method, a propagation environment estimation system, and a propagation environment estimation device, and more particularly to a propagation environment estimation method, a propagation environment estimation device, and a propagation environment estimation system that are suitable for estimating the environment of a wireless signal using a scale model. [Background technology]

[0002] In recent years, the explosive spread of wireless communication devices has led to an increasing demand for wireless communication. However, the frequency resources available for wireless communication are limited. This has made it necessary to utilize previously unused frequencies in addition to existing frequencies. When using a new frequency band, it is necessary to investigate in advance the propagation characteristics of wireless signals in the service area and the impact of interference that signals in the new frequency band may have on other systems.

[0003] In response to these demands, the International Telecommunication Union (ITU) Radiocommunication Sector (ITU-R) is attempting to measure the propagation characteristics of wireless signals in real areas and develop propagation models based on various measurement results. However, these types of attempts face challenges, such as insufficient measurement results for unexplored frequencies and insufficient development of propagation models.

[0004] The following Non-Patent Document 1 discloses a method for investigating radio wave reflection conditions using a scale model. Figure 1 is a schematic diagram that compares the process of estimating a propagation model through actual measurements in an actual area with the process of using a scale model to estimate the model through actual measurements.

[0005] As shown in Figure 1, in the scale modeling method, a scale model of an actual urban area is created at a scale of, for example, 1 / 100. Radio signals are then generated in the scale model environment, and the propagation characteristics of the radio waves are measured. This method can significantly reduce the cost of collecting the necessary data compared to measuring the propagation environment in an actual urban area. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Ryuichiro Iwakuma, Yu Funaki, Toyokazu Mine, Shinichi Ichitsubo, “Delay Profile Using Scale Model Method for Microcells in Urban Areas,” 2010 International Conference on Broadband, Wireless Computing, Communication and Applications, Nov. 2010. https: / / ieeexplore.ieee.org / abstract / document / 5633222 Summary of the Invention [Problem to be solved by the invention]

[0007] In urban areas where various buildings coexist, radio waves emitted from a transmitting station are repeatedly reflected, so the direction from which the radio waves arrive at each point within the area varies. For this reason, when launching a new communication service, it is important to estimate the direction from which radio waves will arrive at each point in the target area.

[0008] In conventional methods using scale models, the propagation environment is generally estimated by actually measuring the behavior of radio waves in the scale model environment. In measurements using radio waves, for example, multiple antennas are placed at the measurement point and the arrival direction can be estimated by analyzing the phase difference of the radio waves arriving at them. Alternatively, the arrival direction can be estimated by placing an antenna with sharp directivity at the measurement point and performing omnidirectional scanning with that antenna.

[0009] However, installing multiple antennas at each measurement point on a scale model requires a great deal of cost and effort. Furthermore, antennas with sharp directivity are generally large, making it difficult to fit them into a scale model. Therefore, a key challenge in estimating the radio wave propagation environment using a scale model has been how to easily and inexpensively estimate the direction of arrival of radio waves.

[0010] The present disclosure has been made in consideration of the above-mentioned problems, and has as its first object to provide a propagation environment estimation method for easily and accurately estimating the direction of arrival of radio waves arriving at any measurement point when estimating the propagation characteristics of radio waves using a scale model.

[0011] A second object of the present disclosure is to provide a propagation environment estimation system that, when estimating radio wave propagation characteristics using a scale model, can easily and accurately estimate the direction of arrival of radio waves arriving at any measurement point.

[0012] Furthermore, a third object of the present disclosure is to provide a propagation environment estimation device that, when estimating radio wave propagation characteristics using a scale model, can easily and accurately estimate the direction of arrival of radio waves arriving at any measurement point. [Means for solving the problem]

[0013] In order to achieve the above object, a first aspect is a propagation environment estimation method for estimating a radio wave propagation environment using a scale model, comprising: A model making step to make a scale model; a light source installation step of installing a light source that emits directional light and can scan an irradiation direction on the scale model, the light source being likened to a radio wave transmitting station; a scanning step of scanning the light source through the scale model; a central light searching step of detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning; an irradiation point detection step of detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement straight line; an estimation step of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; It is desirable to include:

[0014] A second aspect is a propagation environment estimation system that estimates a radio wave propagation environment using a scale model, 3D printers to create scale models, an element mounter for mounting a light source that emits directional light and can scan the irradiation direction on the scale model, likening it to a radio wave transmitting station; a control device that controls the 3D printer and the element mounter; The control device a scanning process for scanning the scale model with the light source; a central light search process for detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning process; an irradiation point detection process for detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement line; an estimation process of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; It is preferable that the method is further configured to execute the following.

[0015] A third aspect is a propagation environment estimation device that estimates a radio wave propagation environment using a scale model, A 3D printer section for creating scale models, an element mounter unit for mounting a light source that emits directional light and can scan the irradiation direction on the scale model, the light source being likened to a radio wave transmitting station; A control device unit that controls the 3D printer unit and the element mounter unit, The control device unit a scanning process for scanning the scale model with the light source; a central light search process for detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning process; an irradiation point detection process for detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement line; an estimation process of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; scanning the light source through the scale model; a process of detecting a central light generation state in which a central light is generated toward a measurement point set in the scale model during the scanning process; a process of detecting the position of an illumination point that appears under the central light generation state on a receiving sphere that is placed so that its center coincides with the measurement point; A process of estimating a direction connecting the position of the center and the position of the irradiation point as the arrival direction of the light reaching the measurement point; It is preferable that the method is further configured to execute the following. [Effects of the Invention]

[0016] According to the first to third aspects, when estimating the propagation characteristics of radio waves using a scale model, the direction of arrival of radio waves arriving at any measurement point can be estimated simply and without missing any points. [Brief explanation of the drawings]

[0017] [Figure 1] This is a schematic diagram showing a comparison between estimating a propagation model through actual measurements in an actual area and estimating a model through actual measurements using a scale model. [Figure 2] FIG. 1 is a diagram for explaining an overview of a comparative example to be compared with the propagation environment estimation method according to a first embodiment of the present disclosure. [Figure 3] FIG. 10 is a diagram for explaining a problem in a comparative example and features of a propagation environment estimation method according to a first embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram illustrating a processing flow in the propagation environment estimation method according to the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a block diagram for explaining the configuration of a propagation environment estimation system that performs the series of processes shown in FIG. 4 continuously and fully automatically. [Figure 6] 7 is a flowchart illustrating the flow of processing executed in the transmission environment estimation system shown in FIG. 6. [Figure 7] FIG. 10 is a diagram illustrating a processing flow in a propagation environment estimation method according to a second embodiment of the present disclosure. [Figure 8] FIG. 10 is a diagram for explaining the principle of estimating a propagation distance x in accordance with a propagation environment estimation method according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] Embodiment 1 [Outline of the first embodiment] 2 is a diagram for explaining an overview of a comparative example to be compared with the propagation environment estimation method according to the first embodiment of the present disclosure. The propagation environment estimation method according to the present embodiment is characterized in that it solves the problems that arise in the method of the comparative example shown in FIG.

[0019] FIG. 2 shows an overview of one preferred method for estimating the direction of arrival of radio waves arriving at a specific measurement point using a scale model. More specifically, the upper part of FIG. 2 shows a perspective view of a scale model used in a comparative example method. Even more specifically, the left side of the upper part of FIG. 2 shows a case where a hollow point on the scale model is set as the measurement point for radio waves. Furthermore, the right side of the upper part of FIG. 2 shows a case where a point on the ground surface on the scale model is set as the measurement point for radio waves.

[0020] The bottom part of Fig. 2 shows a flowchart for explaining the flow when estimating the direction of arrival of radio waves using the method of the comparative example. The numbers "1," "2," "3," and "4" shown in the top part of Fig. 2 correspond to the numbers of each step shown in the bottom part of Fig. 2, respectively.

[0021] Similar to the propagation environment estimation method of the present embodiment, the method of the comparative example is suitable as a method for investigating in advance the propagation characteristics of wireless signals in a service area when starting a new wireless communication service, etc. A service area is typically assumed to be an urban area with many buildings or an indoor space inside a building.

[0022] As shown in FIG. 2, in the method of the comparative example, the propagation environment is estimated in the following steps. 1. Create a model of the target area. Hereinafter, this model will be referred to as a "scale model." A scale model is a reproduction of an actual urban space, for example, at a scale of about 1 / 100. Figure 2 shows an example in which an outdoor space is used as the target area, but the interior of a specific building may also be used as the target area.

[0023] 2. A light source is installed to act as a radio wave transmission source. A laser pointer or similar device that emits a laser beam with excellent linearity is used as the light source. The light source is configured so that the direction of the laser beam can be scanned three-dimensionally.

[0024] 3. The receiving sphere is placed so that the measurement point set on the scale model is at its center. The receiving sphere is made of a material that appropriately reflects laser light so that the irradiation point can be identified visually or by an image sensor when the laser light is irradiated. The receiving sphere may be coated with, for example, fluorescent paint to make the irradiation point of the laser light clear. If the measurement point is in midair, a perfect sphere is used as the receiving sphere. On the other hand, if the measurement point is on the ground surface, a hemisphere is used as the receiving sphere.

[0025] 4. Next, measure the direction from which the light reaching the measurement point, i.e., the center of the receiving sphere, comes. Hereafter, this light will be referred to as the "center light." The laser light emitted from the light source is reflected by various elements contained in the scale model, so it may arrive at the measurement point from any direction.

[0026] Here, first, the scanning position of the laser light that generates the central light is searched for. For example, a light-receiving target is placed at the measurement point on the scale model, that is, the point where the arrival direction of the radio waves is to be estimated. In this state, scanning is performed with the laser light to find the state where the light-receiving target is illuminated. Since the light that illuminates the light-receiving target is the "central light," the scanning position that illuminates the light-receiving target can be recognized as the scanning position that generates the central light.

[0027] Once the scanning position that generates the central light is found, a receiving sphere is placed in place of the light-receiving target. At this time, the receiving sphere is placed so that its center coincides with the measurement point. Under this condition, when a central light is generated using the above scanning position, the surface of the receiving sphere is illuminated with light directed toward the center of the receiving sphere. Then, by connecting the illuminated point that appears on the surface of the receiving sphere with the center of the receiving sphere, i.e., the measurement point, the direction of arrival of the light reaching the illuminated point can be detected.

[0028] [Issues of the Comparative Example and Features of the First Embodiment] 3 is a diagram illustrating the problems of the comparative example and the features of the propagation environment estimation method according to the first embodiment of the present disclosure. When estimating the radio wave propagation environment using a scale model, it is necessary to install a light source 10 that emits highly directional light such as laser light within the scale model. Furthermore, light source 10 needs to be installed so that the light travels at a desired angle.

[0029] The receiving sphere 12 shown in Figure 3 is installed on the assumption that the light 14 emitted from the light source 10 travels along a horizontal line 16. In other words, the layout of the light source 10 and receiving sphere 12 shown in Figure 3 is designed on the assumption that the light 14 travels horizontally.

[0030] However, the angle of the light source 10 actually installed may deviate. In other words, it may be difficult to install the light source 10 in the scale model at the angle specified in the design. Figure 3 shows a situation in which the direction of the irradiated light 14 deviates from the information on the horizon 16 under such circumstances.

[0031] If the installation accuracy of the light source 10 deviates from the design value, a situation may occur in which the irradiated light 14 does not hit the receiving sphere 12 at the scanning position where it should be irradiated as the center light onto the receiving sphere 12, as shown in Figure 3. If this situation occurs in the comparative example, the path of the radio wave that would actually occur will be missed.

[0032] The propagation environment estimation method of this embodiment is characterized in that, in order to prevent the above-mentioned oversight, a receiving cylinder 18 is installed in the scale model instead of the receiving sphere 12. The receiving cylinder 18 has a vertically elongated cylindrical shape, that is, a cylindrical shape with a height greater than its diameter. The receiving cylinder 18 reliably irradiates the irradiated light 14 at the appropriate scanning position even if the light source 10 is tilted or the receiving sphere 12 is removed. Therefore, the propagation environment estimation method of this embodiment can reliably prevent the oversight of paths that may occur in the comparative example.

[0033] 4 is a diagram for explaining the flow of processing in the propagation environment estimation method of this embodiment. As shown in FIG. 4, in the propagation environment estimation method of this embodiment, estimation of the propagation environment proceeds in the following steps.

[0034] 11. A scale model of the target area is created at any scale ratio. Figure 4 shows an example where the target area is an indoor space. To simply simulate the environment of the target area, the surfaces of the scale model, i.e., walls, floors, ceilings, fixed objects, etc., may all be horizontal or vertical. In addition, paint may be applied to the surfaces of the walls, etc., or a mirror film may be attached to produce specular reflection.

[0035] 12. As in the comparative example, a light source 10 having directivity such as a laser pointer is installed. The light source 10 is installed with a preset design angle as a target, for example, a horizontal arrangement as a target.

[0036] 13. The receiving cylinder 18 is placed so that it overlaps with the measurement point in the scale model. The height of the measurement point is determined assuming that the light source 10 is placed at the angle specified by the design value. For example, if the design intent is to place the light source 10 at an estimated angle, the measurement point is assumed to be at the same height as the light source 10.

[0037] 14. Next, the light source 10 is scanned to measure the direction from which the light reaching the measurement point is coming. Specifically, first, as in the comparative example, the scanning position of the light source 10 that generates a "center light" that irradiates the center line of the receiving cylinder 18 is searched for. Next, the receiving cylinder 18 is placed so that its center line overlaps the measurement point, and the position of the receiving cylinder 18 that is illuminated by the irradiated light 14 at the searched scanning position is identified. Then, the direction connecting the identified irradiated position and the measurement point is identified as the arrival direction of the irradiated light 14.

[0038] As described above, according to the propagation environment estimation method of this embodiment, even if the installation angle of the light source 10 deviates from the design value, all of the irradiated light 14 that should originally reach the measurement point can be captured by the receiving cylinder 18 without missing any of it. Therefore, according to this embodiment, when estimating the propagation characteristics of radio waves using a scale model, the arrival direction of radio waves arriving at any measurement point can be estimated simply and without missing any of it.

[0039] [Propagation environment estimation system according to the first embodiment] Fig. 5 is a block diagram for explaining the configuration of a propagation environment estimation system that can continuously and fully automatically carry out the series of processes shown in Fig. 4. The system shown in Fig. 5 includes a control device 30 and a storage device 32. The control device 30 includes an arithmetic processing unit. The storage device 32 stores a program to be executed by the arithmetic processing unit. The control device 30 controls each part of the system shown in Fig. 5 by the arithmetic processing unit carrying out processing in accordance with the program.

[0040] In addition to the above programs, the storage device 32 stores various information related to the target area. This information includes the dimensions, location, and radio wave reflectivity of buildings, roads, etc. The storage device 32 also stores dimensional data for various elements that can be used in the scale model. The storage device 32 also stores the results of measurements performed using the scale model, i.e., information on the direction of arrival obtained in the processing of step 14 shown in FIG. 4.

[0041] The system shown in Fig. 5 includes a 3D printer 34. The control device 30 reads various information from the storage device 32 and performs a process to determine the scale. The 3D printer reads information about the target area from the storage device 32 and carves out a scale model at the scale determined by the control device 30. If texture processing is required on a specific portion to match the reflectance of the radio waves and the measurement light, this processing is also performed by the 3D printer 34.

[0042] The system shown in Fig. 5 includes a painting device 36. The painting device 36 is equipped with a paint nozzle that can move three-dimensionally, and can apply a desired paint to any position on the scale model. In response to commands from the control device 30 and based on information read from the memory device 32, the painting device 36 can apply paint to a specified position on the scale model to obtain a desired reflectance.

[0043] The system shown in Fig. 5 includes an element mounter 38. The element mounter 38 has the function of installing various elements, etc., planned for use in the scale model, at any position on the scale model. In this embodiment, a laser pointer, which functions as a light source, and a receiving column 18, which is installed at a measurement point, are installed by the element mounter 38 in accordance with commands from the control device 30.

[0044] The system shown in Fig. 5 further includes an image capture device 40. The image capture device 40 has the function of capturing images of a measurement point set in the scale model from multiple directions. More specifically, the image capture device 40 is configured to capture images of the light-receiving target and the receiving cylinder 18 from all directions. The search for the central light and the estimation of the direction of arrival are both performed based on the data of the images captured by the image capture device 40.

[0045] The propagation environment estimation system shown in Fig. 5 can perform the series of steps shown in Fig. 4 in a seamless and fully automated manner. Therefore, this system can significantly improve the efficiency of the task of estimating the direction of arrival of radio waves in a target area using a scale model.

[0046] The series of processes executed in the propagation environment estimation system, from setting the scale to estimating the direction of arrival of the irradiated light 14, can be divided and represented as shown in the flowchart in Fig. 6. The contents of each step have already been explained, so a repeated explanation will be omitted here.

[0047] [Modification of the first embodiment] In the first embodiment described above, a light-receiving target is installed on the scale model, the central light is searched for, and then the receiving cylinder 18 is installed on the scale model. However, the method for illuminating the receiving cylinder 18 with the central light is not limited to this. For example, two identical scale models may be prepared, one with the receiving cylinder 18 installed and the other with the light-receiving target installed, and both may be scanned by the light source 10 in the same way. In this case, when the light-receiving target is irradiated, the receiving cylinder 18 will inevitably be illuminated with the central light.

[0048] In addition, in this embodiment, the configuration shown in Fig. 5 is realized by a system consisting of multiple devices, but the present disclosure is not limited to this. That is, the configuration shown in Fig. 5 may be realized as a single device in which the illustrated elements are housed in a single housing.

[0049] Embodiment 2 [Features of the second embodiment] Next, a second embodiment of the present disclosure will be described with reference to Figures 7 and 8. The propagation environment estimation method of the first embodiment described above can provide highly accurate estimation of the arrival direction of light reaching the measurement point regardless of the installation angle of the light source 10. However, the method of the first embodiment cannot estimate the propagation distance of the radio wave reaching the measurement point.

[0050] On the other hand, in an environment where a new estimation of the radio wave propagation environment is desired, there may arise a demand to investigate the propagation distance of the radio waves up to the measurement point. In order to meet the above demand, the propagation environment estimation method of this embodiment is characterized in that it utilizes a scale model and provides a highly accurate estimation of the propagation distance of the radio waves up to the measurement point regardless of the installation angle of the light source 10.

[0051] [Features of the second embodiment] 7 is a diagram illustrating the flow of processing in the propagation environment estimation method according to the second embodiment of the present disclosure. In the flowchart shown in Fig. 7, steps 21 and 22 are performed in the same manner as steps 11 and 12 (see Fig. 4) in the first embodiment. As a result, a scale model is created, and light source 10 is installed in it at an appropriate angle.

[0052] In this embodiment, the receiving cylinder 18 is then placed at a reference point in the scale model (step 23). The reference point may be any point included in the scale model, and can be set arbitrarily.

[0053] Next, the linear distance X between the receiving cylinder 18 placed at the reference point and the light source 10 is measured (step 24).

[0054] Next, the difference Y between the transmission height h and the reception height H is measured (step 25). Specifically, first, the height h of the light emitting part of the light source 10 is measured. Next, the scanning position where the reception cylinder 18 is illuminated by the "center light" is searched for. Then, the height H of the position where the reception cylinder 18 is illuminated by the light source 10 at that scanning position is measured. Finally, the difference Y between the height h of the light source 10 and the height H of the irradiation point is calculated.

[0055] Next, the tilt angle θ of the light source 10 is calculated based on the linear distance X measured in step 24 and the height difference Y measured in step 25 (step 26).

[0056] The relationship between the linear distance X, the height difference Y, and the tilt angle θ is shown in the square box in the upper left of Figure 8. As shown here, the relationship tan θ = Y / X holds for these three. The linear distance X to the reference point has already been measured and is therefore known. The height difference Y has also been measured in step 25. Therefore, the tilt angle θ of the light source 10 can be calculated from the above relational expression.

[0057] Referring again to Figure 7, once the processing of step 26 is completed, next, the receiving cylinder 18 is installed at a measurement point different from the reference point (step 27).

[0058] Next, the light source 10 is scanned to perform a new measurement (step 28). Specifically, first, a scanning position where the receiving cylinder 18 installed at the measurement point is illuminated by the central light is searched for. Next, at that scanning position, the height H' of the receiving cylinder 18 at the point where it is illuminated by the light source 10 is measured. Furthermore, the difference y between the height h of the light source 10 and this height H' is calculated.

[0059] Next, based on the tilt angle θ calculated in step 26 above and the height difference y measured in step 28 above, the propagation distance x from the light source 10 to the measurement point is calculated (step 29).

[0060] The relationship between the propagation distance x, the height difference y, and the tilt angle θ is shown in the square box at the bottom left of Figure 8. As shown here, the relationship x = tan θ / y holds for these three. This relationship holds true whether the light from the light source 10 reaches the receiving cylinder 18 directly or after being reflected by a wall or other object. The tilt angle θ was calculated in step 26, and the height difference y was measured in step 28. Therefore, the propagation distance of the light that reaches the receiving cylinder 18, i.e., the propagation distance of the radio waves to the measurement point in the target area, can be calculated from the above relationship based on θ and y, regardless of whether reflection occurs.

[0061] As described above, the propagation environment estimation method of this embodiment utilizes a scale model to easily estimate the direction of arrival of radio waves arriving at a measurement point and the propagation distance of the radio waves. Furthermore, this embodiment can achieve such an effect without determining a strict installation angle for the light source 10.

[0062] As in the first embodiment, the series of procedures performed in this embodiment can be performed in a seamless and fully automatic manner by a propagation environment estimation system or a propagation environment estimation device having the configuration shown in FIG. 5. [Explanation of symbols]

[0063] 10 light source 12 Receiving Sphere 14 Irradiation light 18 Receiving Cylinder 30 Control device 32 Storage device 34 3D printer 36 Painting equipment 38 Element mounter 40 Imaging equipment

Claims

1. A propagation environment estimation method for estimating a radio wave propagation environment using a scale model, comprising: A model making step to make a scale model; a light source installation step of installing a light source that emits directional light and can scan an irradiation direction on the scale model, the light source being likened to a radio wave transmitting station; a scanning step of scanning the light source through the scale model; a central light searching step of detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning; an irradiation point detection step of detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement straight line; an estimation step of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; A propagation environment estimation method including:

2. The center light searching step includes: placing a light-receiving target along the measurement line; detecting a state in which the light receiving target is illuminated by the light as the central light generating state; The irradiation point detection step includes: After detecting the central light generation state, installing the receiving cylinder in the scale model so that the measurement straight line and the center line coincide with each other; 2. The propagation environment estimation method according to claim 1, further comprising the step of detecting a position of an irradiation point that appears on the installed receiving cylinder under the central light generation state.

3. the model creation step includes creating two identical scale models; the light source installation step includes a step of installing the light source on each of the two scale models; the scanning step includes the step of scanning two of the scale models in the same manner with each of the light sources; The center light searching step includes: placing a light-receiving target along the measurement line on one of the scale models; detecting a state in which the light receiving target is illuminated by the light as the central light generating state; The irradiation point detection step includes: placing the receiving cylinder so that its center line coincides with the measurement line of the other scale model; a step of detecting, in a state in which the central light generation state is detected in the one scale model, a position of an irradiation point that appears on the receiving cylinder installed on the other scale model.

4. a reference center light searching step of detecting a reference center light generation state in which a center light is generated toward a point on a reference line passing through a reference point set in the scale model during the scanning process; a step of setting a receiving cylinder whose center line coincides with the reference straight line as a reference receiving cylinder; measuring the linear distance X between the light source and the reference receiving cylinder; measuring a difference Y between the height of the illumination point appearing on the reference receiving cylinder under the reference central light generation condition and the height of the light source; calculating an inclination angle θ of the light source based on the linear distance X and the height difference Y; a step of measuring a difference y between the height of the irradiation point detected in the irradiation point detection step and the height of the light source; Estimating a propagation distance formed between the light source and the illumination point based on the tilt angle θ and the height difference y; 4. The propagation environment estimation method according to claim 1, further comprising:

5. A propagation environment estimation system that estimates a radio wave propagation environment using a scale model, A 3D printer to create scale models, an element mounter for mounting a light source that emits directional light and can scan the irradiation direction on the scale model, likening it to a radio wave transmitting station; a control device that controls the 3D printer and the element mounter, The control device a scanning process for scanning the scale model with the light source; a central light search process for detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning process; an irradiation point detection process for detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement line; an estimation process of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; A propagation environment estimation system configured to further execute the above.

6. The control device a reference center light search process for detecting a reference center light generation state in which a center light is generated toward a point on a reference line passing through a reference point set in the scale model during the scanning process; A process of setting a receiving cylinder whose center line coincides with the reference straight line as a reference receiving cylinder; measuring the linear distance X between the light source and the reference receiving cylinder; measuring a difference Y between the height of the illumination point appearing on the reference receiving cylinder under the reference central light generation condition and the height of the light source; A process of calculating an inclination angle θ of the light source based on the linear distance X and the height difference Y; a process of measuring a difference y between the height of the irradiation point detected in the irradiation point detection process and the height of the light source; A process of estimating a propagation distance formed between the light source and the irradiation point based on the tilt angle θ and the height difference y; The propagation environment estimation system according to claim 5 , further configured to execute the following:

7. A propagation environment estimation device that estimates a radio wave propagation environment using a scale model, A 3D printer section for creating scale models, an element mounter unit for mounting a light source that emits directional light and can scan the irradiation direction on the scale model, the light source being likened to a radio wave transmitting station; A control device unit that controls the 3D printer unit and the element mounter unit, The control device unit a scanning process for scanning the scale model with the light source; a central light search process for detecting a central light generation state in which a central light is generated toward a point on a measurement line passing through a measurement point set in the scale model during the scanning process; an irradiation point detection process for detecting the position of an irradiation point that appears under the central light generation state on a receiving cylinder that is installed so that its center line coincides with the measurement line; an estimation process of estimating a direction connecting the measurement point and the position of the irradiation point as the arrival direction of the light reaching the measurement point; scanning the light source through the scale model; a process of detecting a central light generation state in which a central light is generated toward a measurement point set in the scale model during the scanning process; a process of detecting the position of an illumination point that appears under the central light generation state on a receiving sphere that is placed so that its center coincides with the measurement point; A process of estimating a direction connecting the position of the center and the position of the irradiation point as the arrival direction of the light reaching the measurement point; The propagation environment estimation device is configured to further execute the above.

8. The control device unit a reference center light search process for detecting a reference center light generation state in which a center light is generated toward a point on a reference line passing through a reference point set in the scale model during the scanning process; A process of setting a receiving cylinder whose center line coincides with the reference straight line as a reference receiving cylinder; measuring the linear distance X between the light source and the reference receiving cylinder; measuring a difference Y between the height of the illumination point appearing on the reference receiving cylinder under the reference central light generation condition and the height of the light source; A process of calculating an inclination angle θ of the light source based on the linear distance X and the height difference Y; a process of measuring a difference y between the height of the irradiation point detected in the irradiation point detection process and the height of the light source; A process of estimating a propagation distance formed between the light source and the irradiation point based on the tilt angle θ and the height difference y; The propagation environment estimation device according to claim 7 , further configured to execute the following:

Images