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

Abstract

This disclosure relates to a propagation environment estimation method adapted for estimating the environment of a wireless signal using a scale model. A scale model is created (step 1). A light source that is supposed to be a radiowave transmitting station is installed in the scale model (step 2). A light-receiving element that is supposed to be a radiowave receiver is installed in the scale model (step 3). A measurement region that is set to the scale model is irradiated by the light source, and the level of received light is measured using the light-receiving element (step 4). Data corresponding to the received light level acquired in the preceding step is converted into a received radiowave level (step 5).

Description

Technical Field

[0001] This disclosure relates to a propagation environment estimation method, a propagation environment estimation system, and a propagation environment estimation device, and particularly relates to a propagation environment estimation method, a propagation environment estimation device, and a propagation environment estimation system suitable for estimating the environment of wireless signals using a scale model.

Background Art

[0002] In recent years, with the explosive spread of wireless communication devices, the demand for wireless communication has been increasing. On the other hand, the frequency resources available for wireless communication are limited. Therefore, in addition to existing frequencies, it has become necessary to use frequencies that have not been used so far. 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 influence of interference caused by signals in the new frequency band on other systems.

[0003] Under such requirements, for example, the Radiocommunication Sector of the International Telecommunication Union (ITU-R) has attempted to measure the propagation characteristics of wireless signals in actual areas and formulate propagation models from various measurement results. However, in this type of attempt, problems such as insufficient measurement results for unexploited frequencies and insufficient formulation of propagation models have arisen.

[0004] Non-Patent Document 1 below discloses a method of reproducing the characteristics of propagation loss in a mobile communication environment using a scale model. FIG. 1 is a schematic diagram showing a comparison between the state of estimating a propagation model by actual measurement in an actual area and the state of performing model estimation by actual measurement using a scale model.

[0005] As shown in FIG. 1, in the method using a scale model, for example, a scale model is produced for an actual urban area or the like at a scale such as 1 / 100. Then, a radio signal is generated in the environment of the scale model, and the propagation characteristics of the radio wave are measured. According to such a method, compared with the case of actually measuring the propagation environment in an actual urban area, the cost required for collecting necessary data can be significantly reduced.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described above, the conventional method using a scale model measures the behavior of radio waves in the environment of the scale model to estimate the propagation environment. At this time, the measurement is performed at a frequency changed according to the scale of the scale model. When using a new frequency band, it is necessary to obtain an appropriate radio license each time. In addition, since radio waves are invisible, the propagation situation cannot be visually confirmed.

[0008] The present disclosure has been made in view of the above problems, and unlike the conventional method for estimating propagation characteristics using a scale model, a first object is to provide a propagation environment estimation method capable of measurement without a radio license and visual confirmation of the propagation situation.

[0009] Further, a second object of the present disclosure is to provide a propagation environment estimation system that enables measurement without radio wave permission and visual confirmation of the propagation situation, unlike the conventional method for estimating propagation characteristics using a scale model.

[0010] Furthermore, a third object of the present disclosure is to provide a propagation environment estimation device that enables measurement without radio wave permission and visual confirmation of the propagation situation, unlike the conventional method for estimating propagation characteristics using a scale model.

Means for Solving the Problems

[0011] A first aspect is a propagation environment estimation method for estimating the radio wave propagation environment using a scale model, comprising: a step of creating a scale model; a step of installing a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model; a step of irradiating a measurement range set on the scale model with the light source; a step of measuring the light reception level of the measurement range irradiated by the light source with the light receiving element; a calibration step of converting the data of the light reception level obtained by the measurement into a radio wave reception level; and See, the calibration step includes: obtaining the attenuation characteristics of radio waves in the target area; obtaining the attenuation characteristics of the light emitted from the light source in the scale model; calibrating the received light level data based on the attenuation characteristics of the radio waves and the attenuation characteristics of the light; and It is desirable to include.

[0012] Also, a second aspect is a propagation environment estimation system for estimating the radio wave propagation environment using a scale model, comprising: a 3D printer for creating a scale model; an element mounter for installing a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model; A control device that irradiates the measurement range set on the scale model with the light source and measures the light reception level with the light receiving element. The control device is configured to execute a calibration process that converts the data of the light reception level obtained by the photographing into the reception level of radio waves. 、 the calibration process includes: a process of obtaining the attenuation characteristics of radio waves in the target area; a process of obtaining the attenuation characteristics of the light emitted from the light source in the scale model; a process of calibrating the received light level data based on the attenuation characteristics of the radio waves and the attenuation characteristics of the light; and This is desirable.

[0013] Further, a third aspect is a propagation environment estimation device that estimates a radio wave propagation environment using a scale model, A 3D printer unit that creates a scale model, An element mounting unit that installs a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model, A control device unit that irradiates the measurement range set on the scale model with the light source and measures the light reception level with the light receiving element. The control device unit is configured to execute a calibration process that converts the data of the light reception level obtained by the measurement into the reception level of radio waves. 、 the calibration process includes: a process of obtaining the attenuation characteristics of radio waves in the target area; a process of obtaining the attenuation characteristics of the light emitted from the light source in the scale model; a process of calibrating the received light level data based on the attenuation characteristics of the radio waves and the attenuation characteristics of the light; and This is desirable.

Advantages of the Invention

[0014] According to the first to third aspects, different from the conventional estimation method of propagation characteristics using a scale model, it is possible to measure without a radio license and visually confirm the propagation situation.

Brief Description of the Drawings

[0015]

Figure 1

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Figure 6

[0016] Embodiment 1 [Outline of Embodiment 1] FIG. 2 is a perspective view of a scale model used in the propagation environment estimation method according to Embodiment 1 of the present disclosure, and FIG. 3 is a flowchart of the estimation procedure according to Embodiment 1 of the present disclosure. As shown in FIG. 3, in the propagation environment estimation method of the present embodiment, the estimation of the propagation environment proceeds in the following steps. 1. Create a model of the target area. Hereinafter, this model is referred to as a "scale model". The scale model is, for example, at a scale of about 1 / 100 and reproduces an actual urban space or the like. FIG. 2 shows an example with an outdoor space as the target area, but the interior of a specific building may also be used as the target area.

[0017] 2. Install a light source regarded as a radio wave transmission source. As the light source, for example, a light-emitting diode, an incandescent bulb, or the like can be used.

[0018] 3. Install a light-receiving element regarded as a radio wave receiver. For example, a photoresistor, a photodiode, or a phototransistor can be used as the light-receiving element.

[0019] 4. Cause the light source to emit light and measure the received light level with the light-receiving element. In the area simulating the ground of the scale model in Fig. 2, the white part is the irradiation range and the black part is the non-irradiation range. Also, it shows that the higher the brightness, the higher the received light level.

[0020] 5. Calibrate the received light level data obtained in the previous step according to the actual communication environment and the distance characteristics of the simulation results, and convert the received light level into the radio wave reception level.

[0021] [Precautions in Embodiment 1] (1) When creating a scale model of the target area, it is necessary to appropriately determine what scale to adopt. In this embodiment, typically, the following points are noted when determining the scale.

[0022] (1-a) Installation space for elements, etc. As described above, in this embodiment, in the scale model, it is necessary to install a light-emitting element regarded as a radio wave transmission source and a light-receiving element regarded as a radio wave receiver at that location.

[0023] These elements will be installed on roads and squares within the target area. And the installation space changes according to the scale of the scale model. If an excessive scale is adopted, a situation will occur where these elements cannot be installed at the corresponding location of the scale model. For this reason, in this embodiment, the scale of the scale model is determined so that various elements required for estimating the propagation characteristics do not interfere with buildings, etc.

[0024] (1-b) Reaching distance of the measurement light Figure 4 shows a comparison of two types of scale models with different scales. More specifically, the upper part of Figure 4 shows a scale model with a large scale, and the lower part of Figure 4 shows a scale model with a small scale. In each scale model, the area where the propagation characteristics are to be measured is shown as the "measurement range" 10. Also, the circle of light emitted from the light source regarded as the radio wave transmission source is shown as the "irradiation range" 12.

[0025] In the scale model in the upper part of Figure 4, due to the scale being too large, there is an area within a part of the measurement range 10 that is not covered by the irradiation range 12 of the light source. In this case, even if the light emission intensity from the light source is measured by the light receiving element, it is not possible to obtain the desired data for the entire measurement range 10. On the other hand, in the scale model in the lower part of Figure 4, the entire measurement range 10 is covered by the irradiation range 12. In this case, by measuring the light emission intensity from the light source, the desired data can be obtained for the entire measurement range 10. In view of such circumstances, in the present embodiment, as shown in the lower part of Figure 4, the scale of the scale model is determined so that the entire measurement range 10 fits exactly within the irradiation range 12 without excess or deficiency.

[0026] (2) It is desirable that the behavior of the light regarded as radio waves is consistent with the behavior of radio waves in the actual area. In the propagation characteristic estimation method of the present embodiment, in order to meet the above requirements, attention is paid to the following points.

[0027] (2-a) Reflectivity of radio waves and light The behavior of radio waves is reflected by the reflectivity of radio waves in each part of the target area. Similarly, the behavior of the light emitted from the light source is affected by the reflectivity of light in each part of the scale model. In the present embodiment, surface treatment is performed on each part of the scale model so that the radio wave reflectivity in each part of the target area is consistent with the light reflectivity in each part of the scale model. The surface treatment is performed, for example, by applying paint, texture processing of the model wall surface, etc.

[0028] (2-b) Attenuation rate of radio waves and light The intensity of radio waves attenuates according to the distance from the transmission source. And the attenuation rate is affected by the frequency of the radio waves. On the other hand, the intensity of light also shows attenuation according to the distance from the light source and according to the wavelength of the light. In this embodiment, in order to replace the attenuation of light in the scale model with the attenuation of radio waves in the target area, calibration processing is performed on the data of the received light level obtained by the light receiving element in the scale model. The calibration processing is performed, for example, by multiplying the data of the obtained received light level by the ratio of the attenuation rate of radio waves in the target area to the attenuation rate of light actually measured in the scale model.

[0029] (2-c) Frequency characteristics of radio waves and wavelength characteristics of light The behavior of radio waves in an actual target area is affected by its frequency. In order to estimate the actual behavior of radio waves from the behavior of light in the scale model, it is desirable that the light used in the scale model exhibits behavior similar to that of actual radio waves. In this embodiment, in order to meet the above requirements, the wavelength of the light used for the light source is appropriately selected. Specifically, in this embodiment, several light sources that emit light such as red, blue, and yellow are prepared, and the light source is appropriately selected according to the radio waves planned to be used in the target area.

[0030] [Details of the procedure in Embodiment 1] FIG. 5 shows a flowchart for explaining in detail the procedure of the propagation environment estimation method of this embodiment. The procedure shown in FIG. 5 starts at the stage where information collection such as the dimensions and location of buildings and roads, the reflectivity of radio waves at major locations, and the frequency of radio waves planned to be used has been completed for an actual target area, and the specifications of light sources and the like used for measurement have been determined.

[0031] As shown in FIG. 5, according to this procedure, first, the scale of the scale model to be produced is determined (step 100). In this step 100, paying attention to the above points (1-a) and (1-b), on the essential condition that elements such as light sources can be installed and the irradiation range 12 by the light source covers the entire measurement range 10, a scale without excess or deficiency is determined.

[0032] Next, a scale model is created by a 3D printer (step 102). Here, first, information on the dimensions and arrangements of various buildings and the like existing in the target area is provided to the 3D printer together with the above scale. The 3D printer creates a scale model of the target area according to the provided scale.

[0033] When the processing of the 3D printer is completed, next, reflection processing is performed on the created scale model (step 104). For example, painting processing or surface processing for adjusting the light reflectance to the radio wave reflectance is performed on the model wall surface of the building. The reflection processing in this step may be advanced manually by an operator. Alternatively, the painting processing may be performed by a fully automatic painting device capable of three-dimensionally designating the painting locations. Further, the surface processing may be realized by processing by the 3D printer.

[0034] Next, a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver are installed (step 106). The light source is installed at the installation candidate location of the transmitting station in the scale model, and the light receiving element is installed at the installation candidate location of the receiver in the scale model. The installation of the light source and the light receiving element may be advanced manually by an operator, or may be performed by a fully automatic element mounter without human intervention.

[0035] When the above preparations are completed, next, irradiation of the scale model by the light source is started (step 108). When a light emitting diode or an incandescent bulb is the light source, in this step 108, lighting processing of the light source is performed.

[0036] When irradiation by the light source is started, next, the light reception level in the measurement range 10 is measured (step 110). When the measurement in the measurement range 10 is completed, next, calibration processing is performed (step 112). Specifically, first, the light reception intensity data in the measurement range 10 obtained by the measurement is read out. Next, the ratio of the attenuation rates described in (2 - b) above is calculated for each light reception intensity, and the numerical value and the ratio above are multiplied for each reception point, whereby the radio wave reception level is calculated for each reception point.

[0037] Finally, the set of values for each reception point calculated in step 112 is stored as information representing the reception level of radio waves in a planar manner (step 114).

[0038] [Propagation Environment Estimation System of Embodiment 1] FIG. 6 is a block diagram for explaining the configuration of a propagation environment estimation system capable of continuously and fully automatically advancing the series of processes shown in FIG. 5. The system shown in FIG. 6 includes a control device 20 and a storage device 22. The control device 20 includes an arithmetic processing unit. A program executed by the arithmetic processing unit is stored in the storage device 22. The control device 20 controls each part of the system shown in FIG. 6 by causing the arithmetic processing unit to proceed with processing in accordance with the above program.

[0039] In addition to the above program, the storage device 22 stores various types of information regarding the target area. This information includes dimensions, location values, radio wave reflectivity, etc. of buildings, roads, etc. The storage device 22 also stores dimension data of various elements that can be used in the scale model. Further, the storage device 22 stores the results of measurements performed using the scale model, that is, the planar reception level information obtained in the process of step 112.

[0040] The system shown in FIG. 6 includes a 3D printer 24. The control device 20 reads out various types of information from the storage device 22 and performs the process of step 100, that is, the scale determination process. The 3D printer 24 reads out information regarding the target area from the storage device 22 and cuts out the scale model at the scale determined by the control device 20. When it is necessary to perform texture processing on specific parts in order to align the reflectivities of radio waves and measurement light, the 3D printer 24 also performs that process.

[0041] The system shown in FIG. 6 includes a painting device 26. The painting device 26 includes a paint nozzle that can move three-dimensionally, and can apply a desired paint to any position of the scale model. The painting device 26 can perform painting to obtain a desired reflectance at a designated position of the scale model according to a command from the control device 20 based on the information read from the storage device 22.

[0042] The system shown in FIG. 6 includes an element mounter 28. The element mounter 28 has a function of installing elements that are planned to be used in the scale model at any position of the scale model. In the present 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 a command from the control device 20.

[0043] The element that functions as the receiver installed above receives the light emission from the element that functions as the light source. The received light data is stored in the storage device 22. The control device 20 can estimate the reception level of radio waves generated in the measurement range 10 in a planar manner by performing the calibration process of step 112 on the received light data stored in the storage device 22. The estimated reception level is stored in the storage device 22 as described above.

[0044] As described above, according to the propagation environment estimation method of the present embodiment, unlike the conventional propagation characteristic estimation method using a scale model, it is possible to perform measurement without a radio wave license and confirm the visual propagation situation. Further, according to the estimation method of the present embodiment, the cost required for estimating the propagation environment of the target area can be significantly reduced.

[0045] Further, according to the propagation environment estimation system described with reference to FIG. 6, the propagation environment estimation method of the present embodiment can be advanced as a seamless and fully automatic procedure. Therefore, according to this system, the working efficiency related to the estimation of the propagation environment of the target area can be significantly improved.

[0046] Incidentally, in the above-described Embodiment 1, the configuration shown in FIG. 6 has been described as a system composed of a plurality of devices, but the present disclosure is not limited thereto. That is, the configuration shown in FIG. 6 may be a single device in which the illustrated elements are housed in a single housing.

Explanation of Signs

[0047] 10 Measurement range 12 Irradiation range 20 Control device 22 Storage device 24 3D printer 26 Coating device 28 Element mounter

Claims

1. A propagation environment estimation method for estimating a radio wave propagation environment using a scale model, comprising: creating a scale model; installing a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model; irradiating a measurement range set in the scale model with the light source; measuring a light reception level of the measurement range irradiated by the light source with the light receiving element; a calibration step of converting data of the measured light reception level into a radio wave reception level; and the calibration step includes: obtaining an attenuation characteristic of radio waves in a target area; obtaining an attenuation characteristic of light emitted from the light source in the scale model; calibrating the data of the light reception level based on the attenuation characteristic of the radio waves and the attenuation characteristic of the light; and a propagation environment estimation method.

2. Further comprising a scale setting step of setting a scale of the scale model prior to creating the scale model, the scale setting step includes: obtaining information regarding an installation space of the transmitting station and the receiver in a target area; obtaining dimensions of the light source and the light receiving element; setting the scale so that the light source and the light receiving element fit in corresponding locations of the installation space in the scale model; The propagation environment estimation method according to claim 1, comprising.

3. Further comprising a scale setting step of setting a scale of the scale model prior to creating the scale model, the scale setting step includes: A step of obtaining information on a range in which the radio wave propagation environment should be measured in the target area; A step of recognizing a portion corresponding to the range in the scale model as the measurement range; A step of obtaining information on the irradiation range by the light source; A step of setting the scale so that the measurement range is within the irradiation range; The propagation environment estimation method according to claim 1, comprising:

4. The propagation environment estimation method according to any one of claims 1 to 3, further comprising a step of performing a reflection process on at least a part of the scale model so that the light reflectance in the scale model matches the radio wave reflectance in the target area.

5. The propagation environment estimation method according to any one of claims 1 to 4, further comprising a step of setting the wavelength of the light emitted by the light source based on the frequency of the radio wave assumed to be used in the target area so that the behavior of light in the scale model matches the behavior of radio waves in the target area.

6. A propagation environment estimation system for estimating the radio wave propagation environment using a scale model, comprising: A 3D printer for creating a scale model; An element mounter for installing a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model; A control device for irradiating the measurement range set on the scale model with the light source and measuring the light reception level with the light receiving element, wherein: The control device is configured to execute a calibration process for converting the data of the light reception level obtained by the measurement into a radio wave reception level, and the calibration process includes: A process of obtaining the attenuation characteristics of radio waves in the target area; A process of obtaining the attenuation characteristics of the light emitted from the light source in the scale model; A process of calibrating the data of the received light level based on the attenuation characteristics of the radio wave and the attenuation characteristics of the light. including A propagation environment estimation system.

7. A propagation environment estimation device that estimates the radio wave propagation environment using a scale model, A 3D printer unit that creates a scale model, An element mounter unit that installs a light source imitating a radio wave transmitting station and a light receiving element imitating a receiver on the scale model, A control device unit that irradiates the measurement range set on the scale model with the light source and measures the received light level with the light receiving element, and includes The control device unit is configured to execute a calibration process of converting the data of the received light level obtained by the measurement into a radio wave reception level. The calibration process A process of obtaining the attenuation characteristics of the radio wave in the target area, A process of obtaining the attenuation characteristics of the light emitted from the light source in the scale model, A process of calibrating the data of the received light level based on the attenuation characteristics of the radio wave and the attenuation characteristics of the light, including A propagation environment estimation device.

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