WO2024069965A1

WO2024069965A1 - Propagation environment fabricating device, propagation environment fabricating method, and propagation environment estimation system

Info

Publication number: WO2024069965A1
Application number: PCT/JP2022/036789
Authority: WO
Inventors: 諒太郎谷口; 友規村上; 智明小川; 泰司鷹取
Original assignee: 日本電信電話株式会社
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04

Abstract

The present disclosure relates to a propagation environment fabricating device, a propagation environment fabricating method, and a propagation environment estimation system suitable for utilizing a scale model to estimate an environment of a radio signal. The propagation environment fabricating device of the present disclosure comprises a block group, a computer, and a raising and lowering mechanism. The block group is formed from a plurality of blocks having an arbitrarily defined reflection coefficient with respect to electromagnetic waves. The computer is configured to implement 3D model creation processing for creating a 3D model of a target environment to be reproduced, and setting processing for setting a height of each block on the basis of the 3D model. The raising and lowering mechanism is configured to implement modification processing for modifying the height of each block on the basis of the setting processing.

Description

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

This disclosure relates to a propagation environment creation device, a propagation environment creation method, and a propagation environment estimation system, and in particular to a propagation environment creation device, a propagation environment creation method, and a propagation environment estimation system that are suitable for estimating the environment of a wireless signal using a scale model.

In recent years, the demand for wireless communication has increased with the explosive spread of wireless communication devices. At the same time, the frequency resources available for wireless communication are limited. For this reason, it has become necessary to utilize frequencies that have not been used before, in addition to existing frequencies. When using a new frequency band, it becomes 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.

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

Non-Patent Document 1 discloses a method of reproducing the propagation loss characteristics in a mobile communication environment using a scale model. Scale models created for such a method may have a reflective surface treatment. For example, the scale model is subjected to a surface treatment that reflects visible light with a given reflectance. Next, the visible light emitted from a light-emitting element regarded as the transmitter is regarded as radio waves. Then, by observing the propagation of the visible light, it is possible to estimate the propagation of the radio waves.

When creating the above-mentioned scale models, 3D printers or blocks are used. However, these methods have the problem that a lot of time is required just to create the shape. In addition, after the above-mentioned scale models are created, it is necessary to perform a reflective treatment on the surface. However, urban environments are complex and require detailed processing, which poses technical challenges.

The primary objective of this disclosure is to provide a propagation environment creation device that uses a scale model, which can reduce the creation time and easily perform surface reflection processing in order to solve the above-mentioned problems.

A second objective of this disclosure is to provide a method for creating a propagation environment using a scale model that can shorten the creation time and easily perform surface reflection processing.

Furthermore, a third objective of this disclosure is to provide a propagation environment estimation system that uses a scale model that can shorten the production time and easily perform surface reflection processing.

The first aspect is preferably a propagation environment creation device comprising a block group, a computer, and a lifting mechanism, the block group being formed of a plurality of blocks having an arbitrary reflection coefficient for electromagnetic waves, the computer being configured to perform a 3D model creation process for creating a 3D model of the target environment to be reproduced and a setting process for setting the height of each block based on the 3D model, and the lifting mechanism being configured to perform a change process for changing the height of each block based on the setting process.

The second aspect is a method for creating a propagation environment using a group of blocks formed of blocks having an arbitrary reflection coefficient for electromagnetic waves, and the method preferably includes a 3D model creation step for creating a 3D model of the target environment to be reproduced, a setting step for setting the height of each block based on the 3D model, and a modification step for modifying the height of each block based on the setting step.

The third aspect is a propagation environment estimation system including a scale model unit, a calculation unit, an elevation mechanism unit, an element mounter unit, a control unit, and a storage unit, in which the scale model unit includes a block group formed of a plurality of blocks having an arbitrary reflection coefficient for electromagnetic waves, the calculation unit is configured to perform a 3D model creation process for creating a 3D model based on a target environment and a setting process for setting the height of each block based on the 3D model, the elevation mechanism unit is configured to perform a modification process for changing the height of each block based on the setting process, the element mounter unit is configured to perform an installation process for installing an electromagnetic wave transmitter likened to a radio wave transmitting station and an electromagnetic wave receiver likened to a receiver in the block group, and the control unit is configured to perform an irradiation process for irradiating a measurement range set in the block group with the electromagnetic wave transmitter, a measurement process for measuring the electromagnetic wave intensity with the electromagnetic wave receiver, and a calibration process for converting the electromagnetic wave intensity data obtained by the measurement into a radio wave reception level.

The first to third aspects of the present invention reduce the time required to create a scale model used to estimate the propagation environment, and facilitate surface reflection processing.

FIG. 1 is a perspective view of a scale model used in a conventional propagation environment estimation method. 1 is a flowchart showing an estimation procedure in a conventional propagation environment estimation method. 1A to 1C are diagrams illustrating a scale model before and after deformation in accordance with a first embodiment of the present disclosure. 4 is a flowchart showing an estimation procedure in a propagation environment estimation method according to the first embodiment of the present disclosure. 1 is a diagram illustrating an entire first lifting mechanism according to a first embodiment of the present disclosure. FIG. FIG. 2 illustrates a portion of a first lifting mechanism according to the first embodiment of the present disclosure. 1 is a flowchart showing a transformation procedure of the first scale model in accordance with the first embodiment of the present disclosure. FIG. 1 is a first diagram illustrating a second scale model in accordance with the first embodiment of the present disclosure. FIG. 13 is a second diagram showing the second scale model in accordance with the first embodiment of the present disclosure. 13 is a flowchart showing a transformation procedure of the second scale model in accordance with the first embodiment of the present disclosure. FIG. 11 is a first diagram illustrating a modified example of a block according to the first embodiment of the present disclosure. FIG. 13 is a second diagram illustrating a modified example of a block according to the first embodiment of the present disclosure. 4 is a flowchart showing the entire procedure of a propagation environment estimation method according to the first embodiment. FIG. 14 is a block diagram for explaining the configuration of a propagation environment estimation system capable of continuously and fully automatically carrying out the series of processes shown in FIG. 13.

First embodiment
[Outline of conventional propagation environment estimation methods]
Fig. 1 is a perspective view of a scale model used in a conventional propagation environment estimation method. Fig. 2 is a flowchart showing an estimation procedure in the conventional propagation environment estimation method. As shown in Fig. 2, in the propagation environment estimation method of this embodiment, the estimation of the propagation environment proceeds in the following procedure.

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.

2. Install a light source that acts as a radio wave transmission source. For example, a light-emitting diode or an incandescent light bulb can be used as the light source.

3. Install a light receiving element that acts as a radio wave receiver. For example, a photoresistor, photodiode, or phototransistor can be used as the light receiving element.

4. The light source is turned on and the light receiving level is measured by the light receiving element. In the area that mimics the ground of the scale model in Figure 2, the white parts are the illuminated areas and the black parts are the non-illuminated areas. Also, the higher the brightness, the higher the light receiving level.

5. The light reception level data acquired in the previous step is calibrated to match the actual communication environment and the distance characteristics of the simulation results, and the light reception level is converted to radio wave reception level.

When creating the scale models mentioned above, 3D printers or blocks are used. However, these have the problem that it takes a lot of time just to create the shape. For example, it takes several tens of hours to create a city that spreads over an area of 100m x 100m at a scale ratio of about 1/20.

In addition, after the scale models are created, they need to have their surfaces processed for reflection. However, urban environments are complex and require detailed processing, which poses technical challenges. This disclosure solves these problems.

[Outline of First Embodiment of the Present Disclosure]
Fig. 3 is a diagram showing a scale model before and after deformation according to the first embodiment of the present disclosure. The diagram on the left in Fig. 3 shows the scale model before deformation. The diagram on the right in Fig. 3 shows the scale model before deformation. Numbers enclosed in boxes shown in Fig. 3 correspond to numbers shown in the flowchart in Fig. 4 described later.

The scale model 10 is a block group that includes a plurality of blocks 2. Here, the blocks 2 are rectangular parallelepiped blocks. The surfaces of the blocks 2 are treated to have a reflective appearance. Examples of reflective treatments include plating, polishing, or applying a mirror film.

The reflection process is expected to involve processing that results in different reflectivities depending on the frequency band of the object being measured. The higher the frequency of the radio waves, the lower the power of the waves reflected from the wall. Therefore, the higher the frequency of the object, the lower the reflection process will be.

In the propagation environment estimation of the present disclosure, a scale model 10 is used to reproduce the target environment. That is, the target environment is reproduced by changing the relative height of each of the multiple blocks 2. The specific estimation procedure will be described later.

FIG. 4 is a flowchart showing the estimation procedure in the propagation environment estimation method according to the first embodiment of the present disclosure. As shown in FIG. 4, in the propagation environment estimation method of this embodiment, the estimation of the propagation environment proceeds in the following procedure.

First, in step 100, a group of blocks is created. Specifically, a number of blocks 2 are created and laid out to create the group of blocks that make up the scale model 10. Here, the blocks 2 are rectangular parallelepipeds.

In addition, block 2 has an arbitrary reflection coefficient for visible light. Therefore, block 2 has a surface that is subjected to a reflection treatment. Examples of reflection treatments include plating, polishing, or attaching a mirror film.

Next, in step 102, a 3D model of the target environment to be reproduced is created. This 3D model is created, for example, by a computer.

Next, in step 104, the height of each block is calculated. First, the 3D model created in step 102 is mapped onto the scale model 10 created in step 100. Then, the height of each block 2 is set based on the mapping results.

Next, in step 106, the lifting mechanism is used to push up each block. This changes the height of each block 2 to the height set in step 104.

Next, in step 108, a propagation environment measurement is performed using visible light. Next, in step 110, it is confirmed whether there are any other differences in the target environment that should be measured. Differences in the target environment are assumed to be, for example, the construction of a new building or cars parked on the road. If there are other differences that should be measured, the process returns to step 102 and the process is repeated for the relevant target environment. If there are no other differences that should be measured, the process proceeds to step 112.

Next, in step 112, all blocks are returned to their initial height. This resets the scale model 10 to its initial state.

As described above, the scale model of the present disclosure is formed by creating and combining multiple blocks of the same shape, and then changing the height of each block. In other words, the time required to create the entire scale model can be significantly reduced compared to the conventional method. In addition, the scale model of the present disclosure is created by combining blocks that have been treated with a reflective surface. In other words, the reflective surface treatment is easier than in the conventional method.

[Modification of the first embodiment of the present disclosure]
5 is a diagram showing an entirety of the first lifting mechanism according to the first embodiment of the present disclosure. The scale model 10a is a block group including a plurality of blocks 2a. A lifting mechanism 9 is installed under the scale model 10a. The lifting mechanism 9 is connected to the computer 4. Then, in steps 106 and 112, the computer 4 controls the height of each block 2a.

FIG. 6 is a diagram showing a part of the first lifting mechanism according to the first embodiment of the present disclosure. The block 2a is connected to a gear 6 and a motor 8, and a bundle of multiple gears 6 and motors 8 constitutes the lifting mechanism 9. The gear 6 is, for example, a rack gear. The calculator 4 operates the corresponding gear 6 and motor 8 to lift and lower the corresponding block 2a.

FIG. 7 is a flowchart showing the deformation procedure of the first scale model according to the first embodiment of the present disclosure. First, in step 114, blocks with reflective surfaces are laid out. Here, block 2a is a rectangular parallelepiped.

In addition, block 2a has an arbitrary reflection coefficient for visible light. Therefore, block 2a has a reflective surface. Examples of reflective treatments include plating, polishing, or attaching a mirror film.

Next, in step 116, lifting mechanisms are attached to all blocks. In other words, by attaching gears 6 and motors 8, all blocks 2a are able to perform lifting and lowering operations.

Next, in step 118, the number of rotations of the motors attached to each block is determined by a computer, and a scale model is formed. First, the height of each block 2a is determined according to the 3D model of the scale model to be formed. Next, the number of rotations of the motor required to change the height of each block 2a is calculated by a computer. Then, based on the calculation results, each motor is rotated to form the scale model.

Depending on the size and complexity of the target environment, the above-described deformation procedure requires only a few minutes to create a scale model. In contrast, conventional 3D printers require tens of hours to create a scale model. In other words, by using the above-described deformation procedure, the desired scale model can be created very quickly.

FIG. 8 is a first diagram showing a second scale model according to the first embodiment of the present disclosure. The scale model 10b is a block group including a plurality of blocks 2b. The scale model 10b is deformed by a block pushing-up device 12. The block pushing-up device 12 is placed directly below the block 2 to be pushed up by an XY table 14. That is, in step 106, the height of the block 2 is controlled by the block pushing-up device 12.

Furthermore, FIG. 9 is a second diagram showing a second scale model according to the first embodiment of the present disclosure. The diagram on the left of FIG. 9 is a diagram showing an operation for returning the formed scale model to its initial state. The diagram on the right of FIG. 9 is a diagram showing the scale model returned to its initial state.

The scale model 10b has a top plate 16 on top. The top plate 16 presses down evenly on the scale model 10b, returning the scale model 10b to its initial state. Note that the thing used here is not limited to a top plate, but anything that can uniformly press down the height of all the blocks that make up the scale model 10b will suffice.

FIG. 10 is a flowchart showing the deformation procedure of the second scale model according to the first embodiment of the present disclosure. First, in step 120, blocks with reflective surfaces are laid out. Here, block 2b is a rectangular parallelepiped with an arbitrary reflection coefficient for visible light. Therefore, block 2b has a reflective surface. Examples of reflective treatments include plating, polishing, or applying a mirror film.

Next, in step 122, a block lifting device is installed under the blocks. Then, in step 124, each block is lifted up by the block lifting device to form the desired scale model.

Next, in step 126, a top plate or the like is used to push down all the blocks to make the height of all the blocks uniform. In other words, the scale model 10b is returned to its initial state. As mentioned above, the thing used here is not limited to a top plate, but anything that can push down the height of all the blocks that make up the scale model 10b uniformly will suffice.

Unlike the first scale model, the above-mentioned transformation procedure does not require the use of gears 6 and motors 8. In other words, the size of the entire device can be reduced. As a result, the second scale model can be formed as a high-resolution scale model at a lower cost than the first scale model.

FIG. 11 is a first diagram showing a modified example of a block according to the first embodiment of the present disclosure. Block 2c is a triangular prism block whose base is a right-angled isosceles triangle. Block 2c has an arbitrary reflection coefficient for visible light.

FIG. 12 is a second diagram showing a modified example of a block according to the first embodiment of the present disclosure. Block 2d is a hexagonal prism block whose base is a regular hexagon. Block 2d also has an arbitrary reflection coefficient for visible light.

As mentioned above, the blocks according to this embodiment are not limited to rectangular parallelepipeds. In other words, as long as the blocks have any reflection coefficient for visible light, the bottom surface is not limited to a specific shape.

[Details of the procedure in the first embodiment]
Fig. 13 is a flowchart showing all the steps of the propagation environment estimation method according to embodiment 1. The steps shown in Fig. 13 are started at the stage where information collection is completed for the actual target environment, such as the dimensions and locations of buildings and roads, the radio wave reflectance at main points, and the frequency of the radio waves to be used.

First, in step 128, the target environment of the scale model to be created is set. Next, in step 130, a 3D model of the target environment is created. Here, the 3D model is created based on information regarding the dimensions and placement of various structures and other objects that exist in the target environment. This 3D model is created, for example, by a computer.

Next, in step 132, a scale model is formed. Here, a scale model is created by laying out blocks of the same shape, and the height of each block is changed to form the desired scale model. Details of the formation method are as described above.

Next, in step 134, a light source, which is likened to a radio wave transmitting station, and a light receiving element, which is likened to a receiver, are installed. The light source is installed at a proposed installation location for the transmitting station on the scale model, and the light receiving element is installed at a proposed installation location for the receiver on the scale model. The light source and light receiving element may be installed manually or by a fully automated element mounter.

Once the above preparations are complete, in step 136, illumination of the scale model by the light source begins. If the light source is a light-emitting diode or an incandescent light bulb, this step involves turning on the light source.

When irradiation by the light source begins, the light reception level in the measurement range is measured in step 138. When measurement of the measurement range is completed, a calibration process is performed. The values for each reception point determined by the calibration process are stored as information that represents the radio wave reception level in a planar manner.

[Propagation Environment Estimation System of the First Embodiment]
Fig. 14 is a block diagram for explaining the configuration of a propagation environment estimation system capable of continuously and fully automatically carrying out the series of processes shown in Fig. 13. The system shown in Fig. 14 includes a control device 20 and a storage device 22. The control device 20 includes an arithmetic processing unit. The storage device 22 stores a program executed by the arithmetic processing unit. The control device 20 controls each part of the system shown in Fig. 14 by the arithmetic processing unit carrying out processes according to the above programs.

In addition to the above programs, the storage device 22 stores various information about the target environment. This information includes the dimensions, locations, and radio wave reflectivity of buildings and roads. The storage device 22 also stores dimensional data for various elements that can be used in the scale model. Furthermore, the storage device 22 also stores the results of measurements performed using the scale model, that is, the surface reception level information obtained in the processing of step 138 above.

The system shown in FIG. 14 includes a computer 24. The control device 20 reads various information from the storage device 22 and performs the process of step 128 above, that is, the process of setting the target environment. The computer 24 reads information about the target environment from the storage device 22 and creates a 3D model. Then, based on the created 3D model, the computer 24 calculates the height of each block and sends it to the control device 20. The control device 20 changes the height of each block so that it matches the received height.

The system shown in FIG. 14 includes a scale model 26. The scale model 26 is formed from blocks that provide a reflection coefficient according to the frequency band for the light source used in the measurement. If a scale model for a different frequency band is required, the scale model included in the system is replaced with a block group that includes the corresponding blocks.

The system shown in FIG. 14 also has a lifting mechanism 27 that raises and lowers each block. The lifting mechanism 27 changes the height of each block based on commands from the control device 20.

The system shown in FIG. 14 includes an element mounter 28. The element mounter 28 has the function of installing elements that are planned to be used in the scale model at any position on the scale model. In this embodiment, an element that functions as a light source and an element that functions as a receiver are installed by the element mounter 28 according to instructions from the control device 20.

The element functioning as a receiver installed above receives light emitted from the element functioning as a light source. The received light data is stored in the memory device 22. The control device 20 can estimate the surface reception level of the radio waves generated in the measurement range by performing a calibration process on the received light data stored in the memory device 22. The estimated reception level is stored in the memory device 22 as described above.

As described above, the propagation environment estimation method of this embodiment makes it possible to shorten the time required to create a scale model and easily perform surface reflection processing. Furthermore, the estimation method of this embodiment can significantly reduce the cost required for propagation estimation of the target environment.

Furthermore, according to the propagation environment estimation system described with reference to FIG. 14, the propagation environment estimation method of this embodiment can be carried out as a fully automatic procedure in a continuous manner. Therefore, according to this system, the work efficiency related to the propagation estimation of the target environment can be significantly improved.

In the above-described embodiment, the configuration shown in FIG. 14 is described as a system consisting of multiple devices, but the present disclosure is not limited to this. In other words, the configuration shown in FIG. 14 may be a single device in which the illustrated elements are housed in a single housing.

In addition, in the above-described embodiment, the block group of the present disclosure is described as reflecting visible light, but the present disclosure is not limited to this. In other words, what the block group reflects may be any electromagnetic wave that can be used to estimate the radio wave propagation environment. In this case, the light source corresponds to an electromagnetic wave transmitter, the light receiving element corresponds to an electromagnetic wave receiver, and the light receiving level corresponds to the electromagnetic wave intensity.

2, 2a, 2b, 2c, 2d Block 4 Calculator 6 Gear 8 Motor 9

Lifting mechanism

10, 10a, 10b Scale model 12 Device 24 Calculator 26 Scale model 27 Lifting mechanism 28 Element mounter

Claims

The device includes a group of blocks, a computer, and a lifting mechanism;
the block group is formed of a plurality of blocks having any reflection coefficient for electromagnetic waves,
The computer,
a 3D model creation process for creating a 3D model of the target environment to be reproduced;
A setting process for setting a height of each of the blocks based on the 3D model;
the lifting mechanism is configured to perform a change process for changing a height of each of the blocks based on the setting process.
The propagation environment creation device according to claim 1, wherein the block has a surface that is subjected to a reflective treatment so that the block has a reflectance according to the frequency band to be measured.
The propagation environment creating device according to claim 2, wherein the reflection treatment is at least one of plating, polishing, and attaching a mirror film.
The propagation environment creating device according to claim 1, wherein the lifting mechanism is a gear and a motor attached to the bottom of each of the blocks.
The propagation environment creating device according to claim 1, wherein the lifting mechanism is a block pushing device having an XY table.
A method for creating a propagation environment using a block group formed of blocks having an arbitrary reflection coefficient for electromagnetic waves, comprising the steps of:
a 3D model creation step of creating a 3D model of the target environment to be reproduced;
a setting step of setting a height of each of the blocks based on the 3D model;
a changing step of changing the height of each of the blocks based on the setting step;
A method for creating a propagation environment comprising the steps of:
A propagation environment estimation system including a scale model unit, a calculation unit, a lifting mechanism unit, an element mounter unit, a control unit, and a storage unit,
the scale model portion includes a block group formed of a plurality of blocks having an arbitrary reflection coefficient for electromagnetic waves,
The calculation unit:
A 3D model creation process for creating a 3D model based on a target environment;
a setting step of setting a height of each of the blocks based on the 3D model;
configured to carry out
the lifting mechanism is configured to carry out a changing step of changing the height of each of the blocks based on the setting step;
the element mounter unit is configured to carry out an installation step of installing an electromagnetic wave transmitter, which is likened to a radio wave transmitting station, and an electromagnetic wave receiver, which is likened to a receiver, on the block group;
The control unit:
an irradiation step of irradiating a measurement range set in the block group with the electromagnetic wave transmitter;
a measuring step of measuring electromagnetic wave intensity by the electromagnetic wave receiver;
The propagation environment estimation system is configured to perform a calibration step of converting data on electromagnetic wave intensity obtained by the measurement into a radio wave reception level.
A step of setting a target environment to be reproduced in the 3D model creation step;
a step of installing an electromagnetic wave transmitter, which is likened to a radio wave transmitting station, and an electromagnetic wave receiver, which is likened to a receiver, in the group of blocks;
a step of irradiating a measurement range set in the block group with the electromagnetic wave transmitter;
measuring electromagnetic wave intensity with the electromagnetic wave receiver;
The propagation environment creating method according to claim 6 , further comprising a calibration step of converting data on electromagnetic wave intensity obtained by the measurement into a radio wave reception level.