Radio wave environment evaluation method and wireless communication characteristics evaluation system

Abstract

To accurately calculate the behavior of electromagnetic waves within an actual service area using a calculation model.SOLUTION: A radio wave environment evaluation method corrects the state of a polygon forming a structural model using electromagnetic wave vector measurement data in the real space, when the structural model of an electromagnetic wave scatterer is constructed in computer resources, and characteristics of an electromagnetic field are calculated using the structural model and a ray that simulates a radio wave traveling straight through the real space.SELECTED DRAWING: Figure 5B

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system that transmits information using electromagnetic waves in a radio wave environment where radio wave scatterers exist in the service area. In particular, the present invention relates to a wireless communication characteristics evaluation technology that virtually reproduces the wireless communication state within a service area by measuring the electromagnetic field in the area and numerically analyzing communication performance using computer resources. [Background technology]

[0002] With the worldwide spread of portable wireless information terminals, there is an increasing demand for stable wireless communication services such as wireless calls and wireless data transfers regardless of the surrounding environment. If a radio wave scatterer exists within an area where wireless communication services are provided, the scatterer scatters the electromagnetic waves of the wireless communication medium, causing power fluctuations when the electromagnetic waves radiated from the transmitter reach the receiver. In many cases, this causes a decrease in received power, and creates areas within the area where good quality wireless communication is difficult to achieve.

[0003] Furthermore, if the relative position and attitude of the scatterer and the communicating radio device change dynamically, even within an area where good quality wireless communication is possible, the signal strength received by the receiver may fluctuate over time, causing a deterioration in communication quality or times when communication becomes impossible.

[0004] The formation of such areas and the occurrence of such times are determined by the relative positions of electromagnetic wave scatterers within the service area and the relative positions and mutual attitudes of the transmitters and receivers performing wireless communication. Therefore, when forming a wireless communication network within a service area, it is extremely important to predict the communication conditions regarding the placement of various transmitters and receivers.

[0005] To understand the communication status for a specific transmitter / receiver placement within a service area, it is necessary to actually place the transmitter / receiver within the service area and measure the characteristics of the received electromagnetic waves. However, because wireless communication is strongly affected by electromagnetic wave scatterers surrounding the transmitter / receiver, it may be necessary to prohibit entry into the measurement area to minimize fluctuations during measurement. In addition, it is costly to secure and dispatch personnel and secure the time for the experiment to conduct the communication experiment.

[0006] To solve this problem, a technology has been proposed in which an electromagnetic field calculation model for analyzing wireless communication characteristics within a service area is constructed within a computer, and the electromagnetic field distribution for all transmitter / receiver placement conditions within the area is virtually realized. In order to construct an electromagnetic field calculation model within computer resources, it is necessary to construct within the computer resources a structural model of electromagnetic wave scatterers that affect electromagnetic waves present within the wireless communication service area.

[0007] In principle, data on structures within a service area can be obtained from the design data of the building and the catalog specifications of the fixtures within the area, but such design data is often not publicly available, making it extremely difficult to obtain, and even if the catalog specifications of the fixtures are known, it is generally not easy to determine how the fixtures are arranged within the service area.To solve this problem, point cloud measurement systems that use a measurement system called LIDAR (Light Detection and Ranging), which uses light waves such as visible light and infrared light, are often used.

[0008] LIDAR emits light waves in three dimensions from a single point within a service area, detects the scattered light waves that are reflected back, and measures the three-dimensional coordinates of the point that caused the reflection due to the phase delay based on the direction and distance from that point. The collection of three-dimensional coordinate points obtained by LIDAR is called a point cloud, and attempts are being made to obtain the structure within the service area from this point cloud. A point cloud is a collection of representative points on the surface of structures within the service area, and technology is required to reconstruct the original structure from the point cloud.

[0009] In conventional technology, the original structure is reproduced as a collection of surface elements called polygons, which connect multiple nearby points in a point cloud. However, due to the extremely high degree of freedom in selecting the nearby points that form the polygon and the fact that there are errors in the coordinates of each point that form the point cloud due to measurement errors of the point cloud by LIDAR, the structure model reproduced from the polygon generally exhibits scattering phenomena that differ from those of the actual structure in the electromagnetic waves used for wireless communication. Therefore, it must be said that, at present, it is extremely difficult to obtain an electromagnetic field calculation model of a structure within a service area using only point cloud data obtained by LIDAR.

[0010] A method has been proposed to improve the results of electromagnetic field calculations using a computational model within computer resources that reproduces the wireless communication environment within a service area by modifying a model for electromagnetic field calculations represented by polygons created using point cloud data obtained by LIDAR using physical quantities that can be measured within the service area.

[0011] WO2012 / 172670 A1 describes a technique for using electromagnetic wave measurement values ​​actually measured at a point within a service area and a calculation model for electromagnetic field calculation, and changing structural information for parts of the calculation model that affect the calculated value of the electromagnetic field at that point, thereby bringing the measured value and calculated value of the electromagnetic field at that point closer together.

[0012] Furthermore, WO2008 / 099927 A1 describes a technology for selectively eliminating elements that are less affected by radio waves emitted from a transmitting point from among multiple surface elements that make up an object within an analysis area used by a system for estimating radio wave propagation characteristics, thereby modifying the calculation model to improve the accuracy of electromagnetic field calculations. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] WO2012 / 172670 A1 [Patent Document 2] WO2008 / 099927 A1 Summary of the Invention [Problem to be solved by the invention]

[0014] All of these prior art techniques focus on the property of radio waves traveling in a straight line through free space, and create a calculation model in computer resources by assuming the process by which radio waves traveling in a straight line collide with an obstacle, undergo changes in their direction and power, and then travel in a straight line again through free space.The calculation model is used to estimate the path along which the radio waves will travel, and by estimating and modifying the parts of the calculation model where the radio waves will collide, the electromagnetic wave characteristics calculated in the computer resources are matched with the electromagnetic wave characteristics measured at corresponding points in an actual service area.

[0015] However, in the prior art, there was no guarantee that the process by which radio waves travel within an actual service area could be faithfully reproduced within computer resources, and therefore there was a problem that a calculation model modified using measured values ​​could not necessarily accurately calculate the behavior of electromagnetic waves within an actual service area.

[0016] Therefore, an object of the present invention is to accurately calculate the behavior of electromagnetic waves in an actual service area using a calculation model. [Means for solving the problem]

[0017] A preferred aspect of the present invention is a radio wave environment evaluation method in which a structural model of an electromagnetic wave scatterer is constructed within a computer resource, and when calculating the characteristics of an electromagnetic field using the structural model and rays simulating radio waves traveling in a straight line through real space, the state of polygons constituting the structural model is corrected using electromagnetic wave vector measurement data in real space.

[0018] Another preferred aspect of the present invention is a wireless communication characteristics evaluation system comprising a model generation unit, an electric field calculation unit, and a polygon correction unit, wherein the model generation unit constructs a structural model of an electromagnetic wave scatterer existing in real space within computer resources, the electric field calculation unit performs ray tracing calculations using the structural model to estimate and calculate an estimated electric field intensity in the real space, and the polygon correction unit identifies polygons that need to be corrected among the polygons constituting the structural model based on the arrival direction of the electromagnetic wave actually measured in the real space, and performs the correction. [Effects of the Invention]

[0019] The behavior of electromagnetic waves within an actual service area can be calculated with high accuracy using a calculation model. [Brief explanation of the drawings]

[0020] [Figure 1A] FIG. 1 is a perspective view showing the configuration of a wireless communication performance evaluation system according to an embodiment. [Figure 1B] 1 is a perspective view of a service area of ​​a wireless communication system according to an embodiment of the present invention; [Figure 1C] FIG. 2 is a conceptual diagram illustrating measurement points in the computer resources of the wireless communication system according to the embodiment. [Figure 1D] FIG. 2 is a conceptual diagram showing an electromagnetic field calculation model in the computer resources of the wireless communication system according to the embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing an electromagnetic field calculation model in the computer resources of the wireless communication system according to the embodiment. [Figure 3] FIG. 2 is an explanatory diagram illustrating the operation principle of an electromagnetic field calculation model in the computer resources of the wireless communication system according to the embodiment. [Figure 4] FIG. 1 is an explanatory diagram showing the operation principle of a wireless communication performance evaluation system according to an embodiment. [Figure 5A] FIG. 1 is a block diagram of a wireless communication performance evaluation system according to an embodiment. [Figure 5B] 3 is a flowchart illustrating the operation of the wireless communication performance evaluation system according to the embodiment. [Figure 6A] FIG. 2 is a transparent perspective view showing the structure of an arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 6B] FIG. 2 is a circuit diagram of an arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 7] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 8] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 9] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 10] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 11] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 12] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 13] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 14] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 15] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 16] FIG. 10 is another circuit configuration diagram of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 17A] FIG. 10 is a transparent perspective view showing another example of the structure of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 17B] FIG. 10 is an explanatory diagram showing the geometric arrangement of another structure of the direction of arrival wave measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 18A] FIG. 10 is a transparent perspective view showing another example of the structure of the arrival wave direction measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 18B] FIG. 10 is an explanatory diagram showing the geometric arrangement of another structure of the direction of arrival wave measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 19A]FIG. 10 is an explanatory diagram showing the geometric arrangement of another structure of the direction of arrival wave measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 19B] FIG. 10 is an explanatory diagram showing the geometric arrangement of another structure of the direction of arrival wave measuring device used in the wireless communication performance evaluation system of the embodiment. [Figure 20] 1 is a conceptual diagram illustrating an example of an environment-adaptive wireless communication system that uses a wireless communication performance evaluation system according to an embodiment. [Figure 21] FIG. 10 is a conceptual diagram illustrating an example of another environment-adaptive wireless communication system that uses the wireless communication performance evaluation system of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Examples will be described below with reference to the drawings. However, the present invention should not be construed as being limited to the description of the embodiments shown below. Those skilled in the art will readily understand that the specific configuration can be modified within the scope of the concept and spirit of the present invention.

[0022] In the configurations of the embodiments described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and redundant explanations may be omitted.

[0023] When there are multiple elements having the same or similar functions, they may be described using the same reference numeral with different subscripts. However, when there is no need to distinguish between multiple elements, the subscripts may be omitted.

[0024] The designations "first," "second," "third," etc. in this specification are used to identify components and do not necessarily limit the number, order, or content thereof. Furthermore, numbers used to identify components are used in different contexts, and numbers used in one context do not necessarily indicate the same configuration in another context. Furthermore, this does not prevent a component identified by a certain number from also serving the function of a component identified by another number.

[0025] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings etc. may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings etc.

[0026] All publications, patents, and patent applications cited herein are incorporated by reference in their entirety.

[0027] As used herein, elements referred to in the singular are intended to include the plural unless the context clearly indicates otherwise.

[0028] The embodiments include a plurality of means for solving the above-described problems. One example of such a method is to represent, in coordinates within a computer resource, a set of points (point cloud) obtained by equipment that uses light waves at a plurality of points within a wireless communication service area to measure the distance and direction from the points to each point on a structure that exists within the same area; form a polygon (polygon) within the computer resource with vertices consisting of three or more adjacent points of the point cloud; install a transmitter within the service area; measure the intensity of electromagnetic waves transmitted from the transmitter at a plurality of points within the service area; install a transmitter at a corresponding point in the computer resource and emit radio waves that travel straight in a plurality of three-dimensional directions from the transmitter; when the plurality of radio waves collide with the polygon, sequentially change properties related to the direction, intensity, and phase of the radio waves to calculate the electromagnetic waves at the point where the measurement is performed; compare the measured values ​​in real space with the calculated values ​​in the computer resource and change the normal direction of the polygon so that the two become closer to each other; and estimate the electromagnetic field distribution within the service area within the computer resource.

[0029] As another example, a set of points (point cloud) obtained by equipment that uses light waves at multiple points within a wireless communication service area to measure the distance and direction from the points to each point on a structure that exists within the same area is represented in coordinates in computer resources, a polygon is formed in the computer resources with three or more points of the point cloud that are close to each other as vertices, a transmitter is installed within the service area, the intensity of the electromagnetic waves transmitted from the transmitter is measured at multiple points within the service area, transmitters are installed at corresponding points in the computer resources and radio waves that travel straight in multiple three-dimensional directions are emitted from the transmitter, and when the multiple radio waves collide with the polygon, properties related to the direction, intensity and phase of the radio waves are sequentially changed to calculate the electromagnetic waves at the point where the measurement is performed, and the measured values ​​in the real space and the calculated values ​​in the computer resources are compared to bring the two closer together, and the positions of the points in the point cloud that make up the polygon are changed so that the two are closer together, and the electromagnetic field distribution within the service area is estimated in the computer resources.

[0030] Another example is to express a set of points (point cloud) obtained by equipment that uses light waves at multiple points within a wireless communication service area to measure the distance and direction from the points to each point on a structure that exists within the same area as coordinates in computer resources, form a polygon in the computer resources with three or more points that are close to each other in the point cloud as vertices, install a transmitter within the service area, measure the strength of the electromagnetic waves transmitted from the transmitter and the direction of the incoming waves at multiple points within the service area, install a transmitter at a corresponding point in the computer resources, and transmit multiple signals from the transmitter. A number of radio waves traveling straight in three-dimensional directions are emitted, and when the multiple radio waves collide with the polygon, the properties related to the direction, intensity, and phase of the radio waves are sequentially changed to calculate the electromagnetic waves at the point where the measurement is performed.The measured values ​​in real space are compared with the calculated values ​​in the computer resources, and the positions of the points in the point cloud constituting the polygon in the computer resources that exist in the direction of the incoming waves measured from a position in the computer resources corresponding to the point where the intensity and direction of the electromagnetic waves were measured within the service area are changed so that the two values ​​approach each other, and the electromagnetic field distribution within the service area is estimated within the computer resources.

[0031] Another example is a method for measuring the distance and direction from a plurality of points within a wireless communication service area to each point on a structure within the area using light waves, by expressing a set of points (point cloud) obtained by the equipment using the light waves to the respective points on the structure within the area as coordinates in computer resources, forming a polygon in the computer resources with three or more points adjacent to the point cloud as vertices, installing a transmitter within the service area, measuring the strength of the electromagnetic waves transmitted from the transmitter, and further measuring the direction of the arriving wave at a plurality of points within the service area by spatially distributing a plurality of antennas in the vicinity of the same points, and measuring the phases of the arriving waves received by the antennas as relative phases with respect to one reference phase, and comparing the obtained plurality of relative phases with the plurality of relative phases. a transmitter is installed at a corresponding point in the computer resource and radio waves traveling in a straight line in a plurality of three-dimensional directions are emitted from the transmitter; when the plurality of radio waves collide with the polygon, the properties related to the direction, intensity and phase of the radio waves are sequentially changed to calculate the electromagnetic waves at the point where the measurement is performed; the measured values ​​in real space and the calculated values ​​in the computer resource are compared to each other so that the measured values ​​are closer to each other; and the positions of the points in the point cloud constituting the polygon in the computer resource that exist in the direction of the incoming waves measured from a position in the computer resource corresponding to the point where the intensity and direction of the electromagnetic waves were measured within the service area are changed, and the electromagnetic field distribution within the service area is estimated within the computer resource.

[0032] Another example is a method of expressing a set of points (point cloud) obtained by equipment that uses light waves at multiple points within a wireless communication service area to measure the distance and direction from the points to each point on a structure that exists within the same area as coordinates in computer resources, forming a polygon in the computer resources with three or more points that are close to each other in the point cloud as vertices, installing a transmitter within the service area, measuring the intensity of the electromagnetic waves transmitted from the transmitter, and estimating the direction of the incoming wave from multiple points within the service area by spatially distributing multiple pairs of antennas that are spatially orthogonal to each other near the same points, measuring the phases of the incoming waves received by the antenna pairs as relative phases with respect to a single reference phase, and estimating the direction of the incoming wave from the multiple relative phases obtained and the relative positions of the multiple pairs of antennas. and estimating the polarization direction of the arriving wave from the ratio of the receiving amplitudes of the two antennas forming each antenna pair; installing a transmitter at a corresponding point in the computer resource and emitting radio waves that travel straight in a plurality of three-dimensional directions from the transmitter; when the plurality of radio waves collide with the polygon, sequentially changing properties related to the direction, intensity, and phase of the radio waves to calculate the electromagnetic waves at the point where the measurement is performed; comparing the measured values ​​in real space with the calculated values ​​in the computer resource so that the two values ​​approach each other, and changing the positions of the points in the point cloud that constitute the polygon in the computer resource that exist in the direction of the arriving wave measured from a position in the computer resource that corresponds to the point where the intensity of the electromagnetic wave and the direction of the arriving wave were measured within the service area; and estimating the electromagnetic field distribution within the service area within the computer resource. [Example]

[0033] An embodiment of a wireless communication performance evaluation system that improves the accuracy of communication performance prediction of a wireless communication system and reduces the introduction cost of the system will be described with reference to FIGS. 1A to 1D. FIG. 1A is a perspective view illustrating the configuration of a wireless communication performance evaluation system in a real space. FIG. 1B is a perspective view illustrating a procedure in real space for the wireless communication performance evaluation system to acquire, from among computer resources, location data of structures present within the wireless communication service area. FIG. 1C is a conceptual diagram illustrating a procedure for generating an electromagnetic field calculation model (sometimes simply referred to as a calculation model) for performing electromagnetic field calculations in computer resources using the acquired position data of the structure. Figure 1D is a conceptual diagram of a structural model generated using the acquired structural position data to perform electromagnetic field calculations in a computer resource.

[0034] In the example of wireless communication performance evaluation system 100 in Fig. 1A, room 1, surrounded by a ceiling, floor, and walls, is the area (indoor space) where wireless communication services are provided. The walls are provided with a window 2 and a door 3, and within this area there is a shelf 4 and a table 5. A mobile radio wave measuring device 7 measures the radio wave intensity in a limited space within room 1 generated by the transmission waves of wireless device 10 and the direction of arrival of the radio waves at various points within this space, and generates a measured electromagnetic field intensity distribution 6. The measured electromagnetic field intensity distribution 6 in the figure schematically shows the radio wave intensity on a certain plane (receiving surface) within the space as a density.

[0035] As shown in Figure 1B, a mobile radio wave measuring device 7 moves inside room 1, measuring the strength and direction of radio waves at each location within room 1. The mobile radio wave measuring device 7 moves two-dimensionally across the floor of room 1 and can adjust its height, enabling it to measure radio waves in three-dimensional space. As a result, a measured electromagnetic field strength distribution 6 is generated at each location within room 1. Furthermore, the mobile radio wave measuring device 7 moves to each point within room 1, emits light waves in multiple directions in three dimensions from that point, and by measuring the delayed phase of the reflected waves of those light waves, it is possible to identify the spatial position of a point on the surface of a structure within room 1 from that point in terms of distance and direction.

[0036] As shown in Fig. 1C, measurement points 11 corresponding to the identified spatial positions can be configured as data in computer resources based on the spatial positions of multiple points on the surface of the structure inside room 1. The data can be any data that can identify coordinates in three dimensions based on an arbitrary coordinate system.

[0037] As shown in FIG. 1D, measurement point 11 is used to generate a structural model of room 1 and the electromagnetic wave scatterers of shelf 4 and table 5 in order to construct an electromagnetic field calculation model in computer resources. The structural model is constructed as a connected group of polygons 12 formed with measurement point 11 as vertices. From the connected group, a group of polygons 101 representing the ceiling and walls, a group of polygons 102 representing window 2, a group of polygons 104 representing shelf 4, and a group of polygons 105 representing table 5 are obtained as the structural model for electromagnetic field calculation. A description of well-known methods for forming electromagnetic field calculation models will be omitted. In this example, the polygons are shown as triangles, but other polygonal shapes may also be used.

[0038] The wireless communication performance evaluation system 100 assigns various electrical characteristics of the room 1 and its internal structures, such as a window 2, a door 3, a shelf 4, and a table 5, with respect to electromagnetic waves used for wireless communication as attributes to each connected group of corresponding polygons 12. The electrical characteristics are determined in advance based on the material of each element and stored in computer resources.

[0039] The wireless communication performance evaluation system 100 uses a calculation model in the computer resource represented by each connected group of polygons 12 having various electrical characteristics as attributes to hypothesize a transmission point 110 at a point in the computer resource corresponding to the point where the wireless device 10 is installed in the computer resource.

[0040] Rays representing radio waves traveling straight through free space in multiple directions in three dimensions are emitted from the transmission point 110. When the ray collides with a polygon 12, new intensity, phase, and direction are calculated using the attributes assigned to the connected group to which the polygon 12 belongs, and the process of re-emitting the ray is repeated to obtain an estimated electromagnetic field intensity distribution 106 equivalent to the actually measured electromagnetic field intensity distribution 6 in the computer resources (ray tracing calculation).

[0041] If the behavior of radio waves in real space and the behavior of the calculation model in computer resources were to perfectly match, then the measured electromagnetic field intensity distribution 6 and the estimated electromagnetic field intensity distribution 106 should match. However, there is no guarantee that the process by which radio waves travel within an actual service area can be faithfully reproduced within computer resources. For example, the measured electromagnetic field intensity distribution 6 in Figure 1A and the estimated electromagnetic field intensity distribution 106 in Figure 1D do not match in the four boxes to the left of the upper right corner and the two boxes in front.

[0042] Therefore, in this embodiment, the polygons 12 formed in the computational resources are modified so that the estimated electromagnetic field intensity distribution 106 approaches the actually measured electromagnetic field intensity distribution 6. Specifically, the normals 111 of the polygons 12 are changed. The normals 111 of the polygons 12 are changed for all or some of the polygons 12 as needed.

[0043] In this embodiment, an electromagnetic field calculation model constructed in a computer resource for estimating wireless communication characteristics within a service area using the computer resource is corrected using actual measurement data of radio wave characteristics obtained in an environment where actual wireless communication is performed. Specifically, a structural model for estimating radio wave characteristics within a service area is corrected using the strength and angle of arrival of radio waves actually measured within the area.

[0044] This improves the accuracy of predicting the characteristics of wireless communication systems within a service area using computer resources, reduces the cost of wireless engineering involved in introducing a wireless communication system within the service area, and is effective in reducing the cost of wireless engineering involved in maintaining the system after introduction. [Example]

[0045] 2 is a diagram illustrating the configuration of a wireless communication performance evaluation system according to another embodiment. The difference from embodiment 1 (FIG. 1D) is that wireless communication performance evaluation system 100 changes three-dimensional coordinates corresponding to the positions of measurement points 11 (all measurement points as necessary) formed in the computational resources so that estimated electromagnetic field intensity distribution 106 approaches actually measured electromagnetic field intensity distribution 6. This change changes the shape and direction of polygon 12 having the measurement points as vertices, and also changes normal 111 of polygon 12.

[0046] According to this embodiment, it is possible to change the normal of the polygon 12 having the measurement point 11 without changing the connection structure (topology) of the connection group to which the polygon 12 belongs. Therefore, it is possible to bring the calculation model in the computer resources closer to the topology of the structures existing in the real space within the service area, which has the effect of improving the accuracy of predicting the characteristics of the wireless communication system within the service area using the computer resources compared to the first embodiment. [Example]

[0047] Another example of a wireless communication performance evaluation system according to an embodiment will be described with reference to Figures 3 and 4. In this example, the calculated value of the electric field obtained from a calculation model is compared with the actual measured value, and the polygon (and its surrounding polygons) facing the corresponding receiving point in the model is corrected using the actual measured direction of the radio wave arriving at the point where the deviation exceeds an allowable value. FIG. 3 is a diagram illustrating the configuration of a wireless communication performance evaluation system that improves the accuracy of communication performance prediction of a wireless communication system and reduces the introduction cost of the system. FIG. 4 is a diagram for explaining a method for changing a calculation model for electromagnetic field calculation in a computer resource using the actually measured direction of arrival of a wave.

[0048] The difference from the first and second embodiments is that the wireless communication performance evaluation system 100 identifies, among the measurement points 11 formed in the computational resources, a portion that affects an area where the difference between the measured electromagnetic field intensity distribution 6 and the estimated electromagnetic field intensity distribution 106 is large.

[0049] To identify the part in question, the direction of arrival of the radio waves measured by the mobile radio wave measuring device 7 in the real space corresponding to the area with the large difference is used, and the part in question is estimated to be the measurement point 11 that exists in the direction of arrival in the computer resources.

[0050] As shown in FIG. 3 , the process will be described for a case where there is a region 131 where the estimated electromagnetic field intensity distribution 106 is smaller than the measured electromagnetic field intensity distribution 6 by a predetermined threshold. First, a polygon 12A is identified that exists in a direction corresponding to the arrival direction 121 of the radio wave measured by the mobile radio wave measuring device 7 as viewed from the region 131. Of the multiple polygons 12 that share vertices with polygon 12A, polygon 12B having the ray 21 with the greatest intensity of the colliding ray is selected. Then, the vertices belonging to the selected polygon 12B are changed so that the colliding ray 21 reaches the region 131. As a result, each polygon 12 is changed from the state indicated by the dotted lines in FIG. 3 to the state indicated by the solid lines. Accordingly, the normal 111 of each polygon 12 is changed from the dotted line to the solid line, as in the first embodiment (case A). Note that instead of selecting polygon 12B having the ray 21 with the greatest intensity, a polygon with a colliding ray whose intensity is greater than that of the ray colliding with polygon 12A may be selected.

[0051] The above processing is explained in detail in Figure 4. The estimated electromagnetic field intensity distribution 106 is shown relative to the measured electromagnetic field intensity distribution 6. In the estimated electromagnetic field intensity distribution 106, an area 401 is estimated to have a lower intensity than the measured electromagnetic field intensity distribution 6 (case A). In the estimated electromagnetic field intensity distribution 106, an area 403 is estimated to have a higher intensity than the measured electromagnetic field intensity distribution 6 (case B). By bringing the measured value and the estimated value closer together, it becomes possible to virtually reproduce the wireless communication state with high accuracy.

[0052] In case A, region 401 corresponds to region 402 in real space. Region 402 is the receiving surface Rc. Because the estimated value indicates a lower intensity than the measured value at receiving surface Rc, the system of this embodiment determines that the ray reaching receiving surface Rc in the calculation model for estimation is not the ray that should have arrived there. Considering the direction of the ray that should have arrived as the direction of the arriving wave obtained from the actual measured value, a polygon 12A that exists in the arrival direction 121 of the radio wave obtained from the measured value at receiving surface Rc is calculated. This calculation is the same as the procedure for finding a polygon that collides when a ray is emitted from receiving surface Rc, so it can be processed quickly using normal ray tracing calculations. Once polygon 12A that is thought to emit the ray that should have arrived at receiving surface Rc is identified, the intensity of the rays reaching these polygons, including the surrounding polygons, is checked.

[0053] The reason for including polygons surrounding (or adjacent polygons to) polygon 12A present in radio wave arrival direction 121 is to resolve the problem of measurement errors in the direction of arrival waves obtained from measurement values. In a specific example, the "surrounding polygons" are all polygons that share vertices with polygon 12A obtained by emitting rays from receiving surface Rc toward radio wave arrival direction 121 of the measurement value. In this way, good accuracy can be obtained while suppressing the required calculation scale.

[0054] Within the calculation model, the polygon (priority polygon) 12B to which the ray reaches with the strongest intensity among multiple polygons, including surrounding polygons, is selected, and the coordinates of the vertices of the priority polygon 12B are changed so that the ray 21 incident on the priority polygon 12B reaches the receiving surface Rc. There are various methods for changing the coordinates of these vertices, but the example in Figure 4 employs a method in which the vertex x shared with polygon 12A of the priority polygon 12B is selected and its coordinate is changed. Another example is a method in which the coordinates of all three vertices of the priority polygon are changed simultaneously.

[0055] To bring the measured value of the incoming wave closer to the calculated value of the direction of the light ray, vertex x of polygon 12B is changed to x' as described above. Accordingly, the normals of each polygon change. For example, n is the normal of polygon 12A before the change, and n' is the normal of polygon 12A after the change. As a result of this processing, the electromagnetic wave from polygon 12B reaches receiving surface Rc instead of the electromagnetic wave from polygon 12A. The electromagnetic wave from polygon 12A reaches a receiving surface other than receiving surface Rc. Furthermore, the direction of the electromagnetic waves from other polygons may also change accordingly.

[0056] The processing for a region 403 where the estimated electromagnetic field intensity distribution 106 is larger than the measured electromagnetic field intensity distribution 6 by a predetermined threshold will now be described (case B). Region 403 is defined as the receiving surface Rc. A polygon 12C is identified that exists in a direction 122 corresponding to the arrival direction of the radio waves measured by the mobile radio wave measuring device 7 as viewed from region 403. Of the multiple polygons 12 that share vertices with polygon 12C, a polygon 12D having a colliding ray 22 with the smallest intensity is selected. The vertices belonging to polygon 12D are changed so that the colliding ray 22 reaches region 403 (case B). Note that instead of selecting polygon 12D having a ray 22 with the smallest ray intensity, a polygon having a colliding ray with an intensity smaller than that of the ray colliding with polygon 12C may be selected.

[0057] According to this embodiment, the number of measurement points that need to be changed in order to bring the estimated electromagnetic field intensity distribution 106 closer to the actually measured electromagnetic field intensity distribution 6 can be significantly reduced, so that the time required to change the calculation model in the computer resources to adapt it to the actual environment can be significantly shortened, which has the effect of reducing the wireless engineering costs involved in the introduction and maintenance of wireless communication systems within the service area. [Example]

[0058] 5A is a block diagram illustrating the configuration of a wireless communication performance evaluation system according to a third embodiment. The wireless communication performance evaluation system 500 can be configured using a normal computer. The wireless communication performance evaluation system 500 includes a processing unit CPU, an input unit IN, an output unit OUT, and a main memory MEM. A model generation unit 501, a field calculation unit 502, an error detection unit 203, and a polygon correction unit 504 are implemented in the main memory MEM by software. In addition, a measured field strength / direction of arrival DB 505, a point cloud DB 506, and an estimated field strength DB 507 can be used as databases.

[0059] These elements are connected by a data bus or network (not shown) and are capable of sending and receiving commands and data. These elements may be configured by a single computer, or may be realized by multiple computers working together, such as in a cloud environment. The function of each element will be described later.

[0060] 5B is a diagram illustrating the flow of operations of the wireless communication performance evaluation system of the third embodiment. The description will be made with reference to FIGS. 1 to 5A. First, at any timing, the mobile radio wave measuring device 7 measures the field strength Em and the direction of arrival Dm at any multiple points within the service area (S201). The measured data is stored in the measured field strength / direction of arrival DB 505.

[0061] Next, the mobile radio wave measuring device 7 identifies each point on the surface of the structure within the service area based on the installation position of the mobile radio wave measuring device 7 and the direction and distance from the installation position, and the point cloud, which is a collection of each point, is expressed as coordinates in the computer resources as shown in Fig. 1C (S202). Note that this may be executed on a device separate from the mobile radio wave measuring device 7. The data of the point cloud expressed in coordinates is stored in the point cloud DB 506.

[0062] The electric field calculation unit 502 sets an arbitrary number (M) of receiving planes Rx, which are regions for which the electromagnetic field strength is to be calculated, within the computer resources (S203). Each receiving plane Rx corresponds to the region 401 in Fig. 4. As mentioned above, the computer resources can be realized by a general computer such as a server, and the following processing is implemented by software.

[0063] As shown in FIG. 1D, the model generation unit 501 generates a polygon 12 having vertices that are three or more points included in the point cloud within the computer resources based on the data in the point cloud DB, and constructs a structural model (S204).

[0064] Furthermore, the model generation unit 501 associates the physical constants of the corresponding real-space structures with respect to electromagnetic waves to the polygons 12 formed in the computational resources, and generates a computational model for electromagnetic field calculations that corresponds to the wireless communication service area in the real space in the computational resources.

[0065] The electric field calculation unit 502 performs ray tracing calculations using this calculation model. A transmission point 110 is hypothetically set within the computer resources, and rays simulating radio waves traveling in a straight line through free space are emitted from the transmission point 110 in multiple directions in three-dimensional space. If a ray traveling in a straight line emitted from the transmission point 110 collides with a polygon 12, the process of calculating the radiation direction, initial electric field strength, and phase from the polygon using physical constants related to the structure corresponding to the polygon, and re-emitting the ray is repeated. When a ray collides with a receiving surface Rx, the field strength Ec and phase Dc of the ray are recorded in the estimated electric field strength DB 507 in association with the receiving surface Rx. When the energy of all rays emitted from the transmission point falls below a predetermined reference value, the process ends, thereby obtaining data related to the receiving surface Rx for estimating the electromagnetic field distribution within the area (S205).

[0066] The error detection unit 503 sets a tolerance Δ to be used for comparison with the radio wave characteristics of the real space obtained using the mobile radio wave measuring device 7 (S206), and uses the data from the measured field strength / direction of arrival DB 505 and the data from the estimated field strength DB 507 to compare the radio wave strength Em measured by the mobile radio wave measuring device 7 corresponding to all receiving surfaces Rx with the vector sum obtained by using the phase Dc of the estimated field strength Ec corresponding to each receiving surface Rx (S207, S208, S209, S210).

[0067] If the measured value of radio wave strength and the vector sum of the electric field strength corresponding to Rx are different (no in S209), the polygon correction unit 504 obtains the measured value of the arrival direction of the radio wave measured by the mobile radio wave measuring device 7 at the point in real space corresponding to the receiving surface Rx from the data in the measured electric field strength / arrival direction DB 505 (S211). Using the measured value, a ray is emitted from Rx toward the arrival direction (S212), and the polygon with which the ray collides is identified (S213).

[0068] The polygon correction unit 504 selects vertices of the identified polygon randomly or according to the description of the embodiment in FIG. 4 (S214), and changes the coordinates of the selected vertices (S215, S216, S217). If the vertices of the polygon have been changed, the process returns to S204. When the comparison of the electric field strengths (S209) is completed for all receiving surfaces (no in S210), the process ends or polygon generation (S204) is resumed.

[0069] According to this embodiment, the electromagnetic field calculation model used by the computer resources for predicting wireless communication characteristics within the service area of ​​a wireless communication system can be adaptively changed and corrected to change the radio wave intensity distribution within the area when the system is operating in accordance with the operation and operational status of the system. This increases the operational flexibility of the wireless communication performance evaluation system according to the embodiment, which is effective in expanding the uses of the system. [Example]

[0070] An example of the structure and circuit configuration of a radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment will be described.

[0071] 6A is a see-through perspective view showing an example of the structure of a radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. Slave station units 31 are installed at the centers of the six faces of a virtual cube 30 with 2D sides installed in a three-dimensional rectangular coordinate system that represents the coordinates of an arrival vector 29 of a received wave. A master station unit 32 is installed at the center of gravity of the virtual cube 30. In the figure, slave station units 31 are represented by Ui, and master station unit 32 is represented by T.

[0072] One master station unit 32 and six slave station units 31 are connected by a high-frequency cable 27 that transmits signals in the carrier frequency band and a low-frequency cable 28 that transmits digital signals. The high-frequency cables 27 are of equal length. The antennas mounted on the multiple slave station units 31 installed in the virtual cube 30 are installed three-dimensionally at equal intervals (D) with respect to the center of gravity of the virtual cube 30.

[0073] 6B is a circuit diagram showing an example of the circuit configuration of a radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The master station unit 32 includes a carrier frequency generating circuit 41 that generates a signal with a frequency equal to the carrier frequency used by the wireless communication system, and a master station controller 43 that controls the carrier frequency generating circuit 41. The master station controller 43 is coupled to a centralized control circuit 42.

[0074] The slave station unit 31 is equipped with a slave station antenna 48. A high-frequency mixer 47, a low-pass filter 46, and an analog-to-digital converter 45 are cascade-connected to the slave station antenna 48. The signal received by the slave station antenna 48 is down-converted, and only the low-frequency signal component is input to the analog-to-digital converter 45 and converted into a digital signal, which is then input to the slave station controller 44.

[0075] The output of the carrier frequency generating circuit 41 in the master station unit 32 is input as a local signal to the high-frequency mixer 47 in the slave station unit 31 via the equal-length high-frequency cable 27. The slave station controller 44 in the slave station unit 31 calculates the phase of the signal received by the slave station antenna 48 from the digital signal obtained based on the output signal of the carrier frequency generating circuit 41 in the master station unit 32. The slave station controller 44 transmits the calculated phase of the received signal to the master station controller 43 in the master station unit 32 via the low-frequency cable 28.

[0076] The master unit 32 can calculate the direction of arrival of the radio waves in a three-dimensional rectangular coordinate system using the relative phase of the radio waves transmitted from the slave unit 31 and received by the slave unit antenna 48 equipped on the slave unit and the spatial position of the slave unit antenna.

[0077] Furthermore, the measurement of radio wave intensity may be performed using various known radio wave intensity measurement techniques, and details of known techniques will be omitted.

[0078] According to this embodiment, it is possible to measure the strength and direction of arrival of radio waves at each point within the service area of ​​a wireless communication system, and therefore the wireless communication characteristic prediction system of the embodiment can significantly reduce the amount of numerical calculation required when modifying a calculation model that estimates the value of electromagnetic waves at each location within the service area, which is effective in reducing installation and maintenance costs by reducing the number of wireless engineering man-hours required for installing and maintaining a wireless system. [Example]

[0079] 7 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as in FIG. 6A. The difference from the embodiment of FIGS. 6A and 6B is that slave station unit 31-6 is provided instead of slave station unit 31.

[0080] The slave station unit 31-6 is equipped with a first slave station antenna 48 and a second slave station antenna 49 that are spatially orthogonal to each other. A first variable attenuator 52 and a second variable attenuator 53 are coupled to the first slave station antenna 48 and the second slave station antenna 49, and the outputs of both are added by a high-frequency combining circuit 51 and output.

[0081] A high-frequency mixer 47, a low-pass filter 46, and an analog-to-digital converter 45 are connected in cascade to the high-frequency combining circuit 51. The received signals from the first slave station antenna 48 and the second slave station antenna 49 are weighted in amplitude and combined, and then down-converted so that only the low-frequency signal component is input to the analog-to-digital converter 45, converted into a digital signal, and then input to the slave station controller 44.

[0082] The slave station controller 44 weights the attenuation of the first variable attenuator 52 and the second variable attenuator 53 by a cosine function for one and a sine function for the other, thereby enabling the first slave station antenna 48 and the second slave station antenna 49 to change the direction in which the energy of the radio waves arriving at the slave station unit 31-6 is received at maximum power or minimum power.

[0083] Since electromagnetic waves are transverse waves, polarization, which is the direction of the energy vector of the electric field, exists in a plane perpendicular to the direction of propagation, and the polarization of the incoming radio waves can be determined by the direction of reception at maximum power and the direction of reception at minimum power, which are perpendicular to each other.

[0084] According to this embodiment, it is possible to measure the direction of arrival and polarization of radio waves at each point within the service area of ​​a wireless communication system, and therefore the wireless communication characteristic prediction system of the embodiment can improve the calculation accuracy for estimating the value of electromagnetic waves at each location within the service area, thereby improving the accuracy of wireless communication characteristic prediction within the service area. [Example]

[0085] Fig. 8 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as in Fig. 6A. The difference from the embodiment of Fig. 7 is that slave station unit 31-7 is provided instead of slave station unit 31-6, and master station unit 32-7 is provided instead of master station unit 32-6.

[0086] The slave station unit 31-7 is equipped with a first slave station antenna 48 and a second slave station antenna 49 that are spatially orthogonal to each other. A first variable attenuator 52 and a second variable attenuator 53 are coupled to the first slave station antenna 48 and the second slave station antenna 49, and their respective outputs are branched into two by a first high frequency divider 62 and a second high frequency divider 63, respectively.

[0087] One of the branch outputs is directly combined by a second high-frequency combiner 61, and the combined output is down-converted to the carrier frequency by a cascaded combination of a second high-frequency mixer 57, a second low-pass filter 56, and a second analog-to-digital converter 55, and then converted into a digital signal and transmitted to the slave station controller 44.

[0088] The other of each branch output is combined by a second high frequency combiner 61, with the signal related to the second high frequency divider 63 being connected via a half-wave line 64 in the carrier frequency band and the signal related to the first high frequency divider 62 being connected directly.

[0089] The output of the carrier frequency generating circuit 41 of the master unit 32-7 is input as a local signal to the high frequency mixer 47 and high frequency mixer 57 of the slave unit 31-7 via the high frequency cable 27 of equal length.

[0090] The combined output is down-converted to the carrier frequency by a cascaded combination of a first high-frequency mixer 47, a first low-pass filter 46, and a first analog-to-digital converter 45, and then converted into a digital signal and transmitted to the slave station controller 44. The slave station controller 44 weights the attenuation of the first variable attenuator 52 and the second variable attenuator 53, one using a cosine function and the other using a sine function, thereby controlling the first slave station antenna 48 and the second slave station antenna 49 to receive the energy of the radio waves arriving at the slave station unit 82 at maximum power by referring to the maximum and local maximum values ​​of the two resulting digital signals. This makes it possible to improve the accuracy of measuring the polarization of the arriving radio waves.

[0091] According to this embodiment, the performance of predicting wireless communication characteristics within the service area of ​​a wireless communication system can be improved compared to the embodiment of FIG. [Example]

[0092] 9 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as in FIG. 6A. The difference from the embodiment of FIG. 8 is that slave station unit 31-8 is provided instead of slave station unit 31-7.

[0093] The slave station unit 83 is equipped with a first slave station antenna 48 and a second slave station antenna 49 that are spatially orthogonal to each other. The first slave station antenna 48 and the second slave station antenna 49 are connected to a third port and a fourth port of a hybrid circuit 71. The first port and the second port of the hybrid circuit 71 are coupled to a second port and a fourth port of a rat-race circuit 74 via a first high-frequency variable phase shifter 72 and a second high-frequency variable phase shifter 73, respectively.

[0094] A cascade combination of a second high-frequency mixer 57, a second low-pass filter 56, and a second analog-to-digital converter 55 is connected to the third port of the rat race circuit 74, and the signals received by the first slave station antenna 48 and the second slave station antenna 49 are down-converted to the carrier frequency, converted into digital signals, and transmitted to the slave station controller 44.

[0095] A first high-frequency mixer 47, a first low-pass filter 46, and a first analog-to-digital converter 45 are cascaded to a first port of the rat race circuit 74, and signals received by a first slave station antenna 48 and a second slave station antenna 49 are down-converted to a carrier frequency, converted into digital signals, and transmitted to the slave station controller 44.

[0096] According to this embodiment, the same operation as that of slave station unit 31-7, which uses variable attenuators 52 and 53 in the embodiment of Fig. 8, can be realized by slave station unit 31-8 using first high-frequency variable phase shifter 72 and second high-frequency variable phase shifter 73. This reduces the power consumption of the slave station units and reduces noise in the received signals, extends the continuous operating time of the mobile radio wave characteristics measuring device, and improves the accuracy of radio wave characteristics measurement, thereby reducing radio engineering costs. [Example]

[0097] 10 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as in FIG. 6A. The difference from the embodiment of FIGS. 6A and 6B is that slave station unit 31-9 is provided instead of slave station unit 31.

[0098] The slave station unit 31-9 is equipped with a slave station antenna 48. One branch terminal of a slave station input selector switch 58 is connected to the slave station antenna 48. A cascade connection of a high-frequency mixer 47, a low-pass filter 46, and an analog-to-digital converter 45 is connected to a common terminal of the slave station input selector switch 58.

[0099] A slave station high frequency generating circuit 75 that supplies a local signal in the carrier frequency band is connected to the high frequency mixer 47. The output of the carrier frequency generating circuit 41 of the master station unit 32 is connected to the other branch terminal of the slave station input selector switch 58. The slave station input selector switch 58 is controlled by the slave station controller 44.

[0100] The signal received by the slave station antenna 48 is down-converted, and only the low frequency signal component is input to the analog-to-digital converter 45 , converted into a digital signal, and then input to the slave station controller 44 .

[0101] The slave station unit 31-9 controls the slave station input selector switch 58 so that the output of the slave station antenna 48 is input to the high-frequency mixer 47, and measures the phase of the received wave arriving at the movable radio wave measuring instrument 7. Thereafter, it controls the slave station input selector switch 58 so that the output of the carrier frequency generating circuit 41 of the master station unit 32 is input to the high-frequency mixer 47, and measures the phase of the output of the carrier frequency generating circuit 41. The results of each phase measurement are transmitted to the master station controller 43 of the master station unit 32 via the low-frequency cable 28.

[0102] The master unit 32 can calculate the direction of arrival in the three-dimensional rectangular coordinate system using the relative phase of the radio waves transmitted from the slave unit 31-9 and received by the slave antenna 48 and the output of the carrier frequency generating circuit 41, and the spatial position of the slave antenna 48.

[0103] According to this embodiment, the slave unit can supply a local signal for measuring the phase of the incoming wave from its internal carrier frequency generating circuit without receiving it from an external device via a cable. This has the effect of stabilizing the mixer operation that down-converts the incoming wave signal, and improving the accuracy of measuring the phase of the incoming wave. [Example]

[0104] 11 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as that of FIG. 6A. The differences from the embodiments of FIGS. 6A and 6B are that slave station unit 31-10 is provided instead of slave station unit 31, master station unit 32-10 is provided instead of master station unit 32, and optical fiber 26 is provided between slave station unit 31-10 and master station unit 32-10 instead of high-frequency cable 27 for transmitting lightwave signals.

[0105] The master unit 32-10 is equipped with a photo LED 65, which generates a synchronization signal in the form of an optical wave having a frequency an order of magnitude higher than the carrier frequency, generated by an optical modulator 114. The frequency of the optical modulator 114 is controlled by a master controller 43, which is coupled to the centralized control circuit 42.

[0106] The slave station unit 31-10 has a slave station antenna 48. A high-frequency mixer 47, a low-pass filter 46, and an analog-to-digital converter 45 are cascade-connected to the slave station antenna 48. A slave station high-frequency generating circuit 75 that supplies a local signal in the carrier frequency band is connected to the high-frequency mixer 47, and the frequency of the slave station high-frequency generating circuit 75 is controlled by the slave station controller 44. The signal received by the slave station antenna 48 is down-converted, and only the low-frequency signal component is input to the analog-to-digital converter 45 and converted into a digital signal, which is then input to the slave station controller 44.

[0107] The synchronization signal generated by the master unit 32-10 is transmitted to a photodiode 113 via an optical fiber 26. The signal received by the photodiode 113 is converted into a digital signal by an optical demodulator 112 and input to a slave station controller 44. The slave station controller 44 calculates the phase of the slave station high frequency generating circuit 75 relative to the synchronization signal.

[0108] Each slave unit 31-10 determines the phase of the received wave based on the initial phase of its own slave unit high frequency generating circuit 75. After receiving the radio wave, the receiving unit 35 transmits to the master unit 32-10 the measured phase of the radio wave and the relative phase of the slave unit high frequency generating circuit 75 with respect to the synchronization signal generated by the master unit 32-10.

[0109] The master unit 32-10 can estimate the direction of arrival of the radio wave of the wireless communication system arriving at the mobile radio wave measuring instrument 7 by using these two types of phases transferred from each slave unit 31-10.

[0110] According to this embodiment, optical fiber can be used instead of the high-frequency cable that connects the slave station unit and master station unit, which is effective in reducing the weight and cost of the device by making the components for manufacturing the radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment smaller and lighter. [Example]

[0111] Fig. 12 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as that of Fig. 6A. The differences from the embodiment of Fig. 11 are that slave station unit 31-11 is provided instead of slave station unit 31-10, master station unit 32-11 is provided instead of master station unit 32-10, and optical fiber 26 existing between slave station unit 31 and master station unit 32 is eliminated.

[0112] The master unit 32-11 is equipped with a high-power photo LED 95 instead of the photo LED 65, and the slave unit 31-11 is equipped with a high-sensitivity photo diode 97 instead of the photo diode 113. The high-power photo LED 95 generates a synchronization signal generated by an optical modulator 114 as a light wave with a frequency that is an order of magnitude higher than the carrier frequency. Optical communication is performed using the high-power photo LED 95 and the high-sensitivity photo diode 97, making it possible to optically transmit a synchronization signal using free space.

[0113] According to this embodiment, the optical fiber connecting the slave station unit and master station unit can be reduced, which is effective in reducing the weight and cost of the radio wave characteristic measuring device used in the wireless communication characteristic prediction system compared to the embodiment of Figure 11. [Example]

[0114] 13 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as that of FIG. 6A. The differences from the embodiments of FIGS. 6A and 6B are that slave station unit 31-12 is provided instead of slave station unit 31, master station unit 32-12 is provided instead of master station unit 32, and there is no high-frequency cable for transmitting high-frequency signals between slave station unit 31 and master station unit 32.

[0115] The master station unit 32-12 is equipped with a master station antenna 78. A master station high frequency mixer 67, a master station low pass filter 66, and a master station analog-to-digital converter 65 are cascade-connected to the master station antenna 78 via a master station transmit / receive switch 68. A master station high frequency generating circuit 79 that supplies a local signal in the carrier frequency band to the master station high frequency mixer 67 is connected via the master station high frequency switch 69, and the frequency of the master station high frequency generating circuit 79 is controlled by the master station controller 43.

[0116] The master station transmit / receive selector switch 68 and master station high frequency switch 69 are controlled by the master station controller 43, and when the master station unit 32-12 receives an incoming wave, the selector terminal of the master station high frequency generating circuit 79, whose common terminal is connected to the master station antenna 78, is switched to the signal input of the master station high frequency mixer 67, and the selector terminal of the master station high frequency switch 69, whose common terminal is connected to the master station high frequency generating circuit 79, is switched to the local input of the master station high frequency mixer 67. The signal received by the master station antenna 78 is down-converted, and only the low frequency signal component is input to the master station analog-to-digital converter 65 and converted to a digital signal, which is then input to the master station controller 43, and the master station controller 43 is connected to the centralized control circuit 42.

[0117] The slave station unit 31-12 is equipped with a slave station antenna 48. A high-frequency mixer 47, a low-pass filter 46, and an analog-to-digital converter 45 are cascade-connected to the slave station antenna 48. A slave station high-frequency generating circuit 75 that supplies a local signal in the carrier frequency band is connected to the high-frequency mixer 47. The frequency of the slave station high-frequency generating circuit 75 is controlled by the slave station controller 44. The signal received by the slave station antenna 48 is down-converted, and only the low-frequency signal component is input to the analog-to-digital converter 45 and converted into a digital signal, which is then input to the slave station controller 44.

[0118] When the master station unit 32-12 transmits a reference signal, the switching terminal of the master station high frequency generating circuit 79, whose common terminal is connected to the master station antenna 78, is connected to the switching terminal of the master station high frequency switch 69. The output of the master station high frequency generating circuit 79 is transmitted from the master station antenna 78 as a reference wave.

[0119] Each slave unit 31-12 determines the phase of the received wave based on the initial phase of its own slave unit high frequency generating circuit 75. The master unit 32-12 transmits the output of the master unit high frequency generating circuit 79 at a timing when there is no signal in the frequency band used for communication and control by the wireless system.

[0120] Because the frequency band of the carrier wave of the incoming radio wave of the wireless system received by the slave unit 31-12 is the same as the frequency band of the reference wave transmitted by the master unit 32-12, the receiving unit 35 measures two different phases. If it is arranged in advance that the slave unit 31-12 transmits the measured phase of the radio wave to the master unit 32-12 immediately after receiving the radio wave, the master unit 32-12 can determine whether the radio wave received by the slave unit 31-12 is a radio wave used by the wireless system or a radio wave transmitted by the master unit 32-12, using the timing of transmission from the slave unit 31-12.

[0121] The master unit 32-12 can estimate the direction of arrival of the radio wave of the wireless communication system arriving at the mobile radio wave measuring instrument 7 by using these two types of phases transferred from each slave unit 31-12.

[0122] According to this embodiment, a plurality of slave stations equipped with antennas are arranged three-dimensionally at equal intervals around one master station equipped with an antenna, and the measured phases of the incoming waves measured by the plurality of slave stations are transmitted to the master station, and the master station calculates the direction of the incoming wave using its own measured phases of the incoming waves and the measured phases of the incoming waves transmitted by the slave stations. Since a high-frequency cable connecting the slave station units and the master station units is not required, the number of components required to manufacture the radio wave characteristic measuring device used in the wireless communication characteristic prediction system is reduced, which is effective in reducing the weight and cost of the device. [Example]

[0123] 14 is a diagram illustrating an example of the structure and circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of slave station unit 31 and master station unit 32 may be the same as in FIG. 6A. The difference from the embodiment of FIG. 13 is that slave station unit 31-13 is provided instead of slave station unit 31-12.

[0124] The slave station unit 31-13 has a first slave station antenna 48 and a second slave station antenna 49 that are spatially orthogonal to each other. The first slave station antenna 48 and the second slave station antenna 49 are connected to a third port and a fourth port of a hybrid circuit 71. A cascade combination of a first high-frequency mixer 47, a first low-pass filter 46, and a first analog-to-digital converter 45 is connected to the second port of the hybrid circuit 71. A cascade combination of a second high-frequency mixer 57, a second low-pass filter 56, and a second analog-to-digital converter 55 is connected to the first port of the hybrid circuit 71.

[0125] The output of a slave station high frequency generating circuit 75, which supplies a local signal in the carrier frequency band, is coupled to the first high frequency mixer 47 and the second high frequency mixer 57, and the frequency of the slave station high frequency generating circuit 75 is controlled by the slave station controller 44. The signals received by the first slave station antenna 48 and the second slave station antenna 49 are down-converted and converted into digital signals and then input to the slave station controller 44. The slave station unit 31-13 uses the output of the slave station high frequency generating circuit 75 as a local signal, down-converts the signals received by the first slave station antenna 48 and the second slave station antenna 49, and then converts them into digital signals via two paths.

[0126] At this time, the digital signal for the first path and the digital signal for the second path become cosine and sine values ​​with respect to the polarization angle in the plane spanned by the first slave station antenna 48 and the second slave station antenna 49. This allows the slave station controller 44 to immediately identify the polarization of the radio waves received by the radio wave characteristics measuring device. Furthermore, if the frequency of the slave station high-frequency generating circuit 75 is made variable and a small frequency deviation is provided with respect to the carrier frequency, the values ​​of the two digital signals input to the slave station controller 44 change in a rotational relationship at the deviation frequency, making it possible to identify the polarization of the received radio waves on the time axis and improving the measurement accuracy of the polarization.

[0127] The method of determining the direction of arrival of the received wave by the master unit 32-12 using the calculated value of the phase of the received wave transmitted by the slave unit 31-13 is the same as in the embodiment of FIG.

[0128] According to this embodiment, it is possible to achieve both a reduction in weight and cost of the radio wave characteristic measuring device used in the wireless communication characteristic prediction system and an improvement in the measurement accuracy of the angle of arrival and polarization of the received radio wave. [Example]

[0129] 15 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of the slave station unit 31 and the master station unit 32 may be the same as that of FIG. 6A. The difference from the circuit configuration of the radio wave characteristic measuring device of the embodiment of FIG. 13 is that the slave station high-frequency generating circuit 75 in the slave station unit 31-14 is replaced with a slave station quadrature modulator 76, and the master station high-frequency generating circuit 79 in the master station unit 32-14 is replaced with a master station quadrature modulator 77.

[0130] The slave station quadrature modulator 76 and the master station quadrature modulator 77 are supplied with digital I / Q signals from the slave station controller 44 and the master station controller 43, and can generate signals in the carrier frequency band at any initial phase in response to the I / Q signals.

[0131] According to this embodiment, the variable frequency generating circuit can be realized by a digital circuit, which is effective in reducing the size and cost of the radio wave characteristic measuring device. [Example]

[0132] 16 is a diagram illustrating an example of the circuit configuration of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment. The geometric arrangement of the slave station unit 31 and the master station unit 32 may be the same as that of FIG. 6A. The difference from the circuit configuration of the radio wave characteristic measuring device of the embodiment of FIG. 14 is that the slave station high-frequency generating circuit 75 in the slave station unit 31-15 is replaced with a slave station quadrature modulator 76, and the master station high-frequency generating circuit 79 in the master station unit 32-15 is replaced with a master station quadrature modulator 77.

[0133] The slave station quadrature modulator 76 and the master station quadrature modulator 77 are supplied with digital I / Q signals from the slave station controller 44 and the master station controller 43, and can generate signals in the carrier frequency band at any initial phase in response to the I / Q signals.

[0134] The effect of this embodiment over the embodiment of FIG. 14 is similar to the effect that the embodiment of FIG. 14 has over the embodiment of FIG. [Example]

[0135] 17A and 17B are diagrams illustrating an example of the structure of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment.

[0136] As shown in FIG. 17A, slave station units 31 are installed at the eight vertices of a virtual cube 30 with 2D sides installed in a three-dimensional rectangular coordinate system, and a master station unit 32 is installed at the center of gravity of the virtual cube 30.

[0137] One master unit 32 and each of the eight slave units 31 are connected by a high-frequency cable 27 that transmits signals in the carrier frequency band and a low-frequency cable 28 that transmits digital signals. The high-frequency cables 27 are of equal length.

[0138] The antennas mounted on the multiple slave station units 31 installed in the virtual cube 30 are installed three-dimensionally at equal intervals (√3D) with respect to the center of gravity of the virtual cube 30.

[0139] As shown in FIG. 17B, by using a regular octahedron 37 circumscribing the virtual cube 30, eight slave station units 31 can be installed on the eight faces of the regular octahedron 37, thereby improving the robustness of the structure of the radio wave characteristics measuring device.

[0140] The accuracy of calculating the direction of arrival is also improved because the number of relative phases of radio waves received by each antenna uniformly distributed in three-dimensional space that the master unit can use to determine the direction of arrival of the radio waves increases.

[0141] Compared to the embodiment of FIG. 6, this embodiment has the advantage of reducing the prediction error of the direction of arrival of received radio waves while maintaining the robustness of the radio wave characteristic measuring device. [Example]

[0142] 18A and 18B are diagrams illustrating an example of the structure of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment.

[0143] As shown in FIG. 18A, slave station units 31 are installed at the twelve vertices of a virtual cube 30 with a side length of 2D installed in a three-dimensional rectangular coordinate system, and a master station unit 32 is installed at the center of gravity of the virtual cube 30.

[0144] One master unit 32 and each of the twelve slave units 31 are connected by a low-frequency cable 28 that transmits digital signals.

[0145] The antennas mounted on the plurality of slave station units 31 installed in the virtual cube 30 are installed three-dimensionally at equal intervals (√2D) with respect to the center of gravity of the virtual cube 30 .

[0146] As shown in FIG. 18B, by using a regular dodecahedron 38 circumscribing the virtual cube 30, it becomes possible to install twelve slave station units 31 on the twelve faces of the regular dodecahedron 38, thereby improving the robustness of the structure of the radio wave characteristics measuring device.

[0147] Since the number of relative phases of radio waves received by each antenna uniformly distributed in three-dimensional space that the master unit can use to determine the direction of arrival of the radio waves increases, the accuracy of calculating the direction of arrival is also improved.

[0148] This embodiment has the advantage of reducing the prediction error of the direction of arrival of received radio waves while maintaining the robustness of the radio wave characteristic measuring device, compared to the embodiment of FIG. [Example]

[0149] 19A and 19B are diagrams illustrating an example of the structure of another radio wave characteristic measuring device used in the wireless communication characteristic prediction system of the embodiment.

[0150] As shown in Figure 19A, two squares with sides of 2D that are similar to the faces of a virtual cube 30 with sides of 3D and inscribed in the face of the virtual cube 30 with sides of 3D set in a three-dimensional rectangular coordinate system are set so that one vertex overlaps the diagonal vertex of the face of the virtual cube 30 with sides of 3D.

[0151] A slave station unit 31 is installed at each vertex of the two 2D squares. Each face of the 3D virtual cube 30 has two slave station units 31, one at each diagonal vertex, four on each side, and two near the center of gravity of the face, for a total of eight slave station units 31. These faces are assembled into a rectangular parallelepiped so that the slave station units 31 located at six vertices and sides are common, and a total of 28 slave station units 31 are installed on the rectangular parallelepiped.

[0152] FIG. 19A shows a state in which a slave station unit 31 is placed on the surface of a virtual cube 30, and a master station unit 32 is placed at the center of gravity.

[0153] 19B is a diagram illustrating the operation of attenuating received waves arriving from multiple directions by eight slave station units 31 arranged on one face of a virtual cube 30. In Fig. 19B, radio waves arriving from different directions θ1, θ2, and θ3 are added in opposite phases in two paired slave station units 31, thereby making it possible to attenuate the power of the radio waves arriving from the directions θ1, θ2, and θ3.

[0154] By performing this operation for each pair of spatially orthogonal planes, even if radio waves arriving at the mobile radio wave measuring device 7 come from up to four different directions, the directions of arrival of multiple incoming waves for each of the parallel planes can be calculated using 24 of the total 28 slave station units.By performing similar processing for all three pairs of planes, it is possible to estimate the directions of arrival of up to four radio waves arriving at the mobile radio wave measuring device 7 in three dimensions.

[0155] In this way, slave station units are arranged so that 2^N parallel line segments of equal length with N different inclinations are formed on one face of a regular hexahedron, and the phases of the arriving waves measured by the slave station units are used to attenuate the power of radio waves in specific directions of arrival, thereby estimating the directions of arrival of up to N+1 radio waves.For example, one or more virtual squares are formed on one face of a regular hexahedron, and slave station units are arranged at all vertices of the virtual squares.

[0156] According to this embodiment, it is possible to refine the calculation model for estimating the radio wave environment in which the wireless communication system operates, which has the effect of improving the accuracy of prediction of the communication performance of the wireless system. [Example]

[0157] 20 is a diagram illustrating an example of the configuration of an environment-adaptive wireless communication network that uses a wireless communication characteristic prediction system that enables reduction in the implementation cost of a wireless system that provides communication services. A shelf 4 and a table 5 are placed inside a room 1, which is the service area for wireless communication, and there are movable obstacles 9 such as people and robots that move within the area. A plurality of master stations 18 and a plurality of slave stations 19 that communicate wirelessly with the master station 18 are installed on the floor, walls, and ceiling that form the indoor space.

[0158] A calculation model for calculating the electromagnetic field within the service area is constructed in the computer resources, and this calculation model includes a group of polygons 101 (not shown) representing the floor, ceiling, and walls, a group of polygons 104 representing the shelf 4, and a group of polygons 105 representing the table. The group of polygons corresponding to the movable obstacle 9 is not included in the calculation model because the position of the movable obstacle cannot be specified in advance.

[0159] Within the computer resources, transmission points 118 corresponding to a plurality of master stations 18 and reception points 119 corresponding to slave stations are arranged. If the communication quality between a specific master station and slave station within the service area deteriorates below a predetermined threshold, the computer calculates the communication characteristics of pairs of transmission points and reception points other than the corresponding pair of transmission points and reception points within the computer resources, searches for that slave station and a new master station that exhibit good communication characteristics using a computational model within the computer resources, and if such a master station is predicted, controls the corresponding master station in real space to start communication with the slave station that is communicating with poor quality.

[0160] According to this embodiment, the master station that communicates with the slave station can be changed in response to deterioration in wireless communication quality that occurs within the service area, which has the effect of restoring the communication quality of the slave station and is effective in improving the communication reliability and throughput of a wireless network consisting of multiple master stations and slave stations. [Example]

[0161] Fig. 21 is a diagram illustrating an example of the configuration of another environment-adaptive wireless communication network that uses a wireless communication characteristic prediction system that enables a reduction in the implementation cost of a wireless system that provides communication services. Differences from the example in Fig. 20 will be mainly described.

[0162] In this embodiment, a group of polygons corresponding to the movable obstacle 9 is created separately, but is not placed in advance in the calculation model.

[0163] Within the computer resource, transmission points 118 corresponding to multiple master stations 18 and reception points 119 corresponding to slave stations are arranged. When the communication quality between a specific master station and slave station within the service area deteriorates below a predetermined threshold, the communication characteristics of the corresponding transmission point and reception point within the computer resource are calculated. If the communication quality between the master station and slave station communicating in real space deteriorates beyond a predetermined allowable value based on the communication quality obtained through the calculation, it is determined that an obstacle to radio waves exists between the corresponding transmission point and reception point within the computer resource, and a polygon group 109 created in advance is virtually added between the transmission point and reception point.

[0164] The polygon group 109 corresponding to the movable obstacle 9 is moved within an area that blocks the path connecting the transmission point and reception point of the calculation model, and the calculation values ​​of the communication quality between the transmission point and reception point are sequentially obtained. The position of the polygon group 109 that gives the calculation value of the communication quality closest to the reception quality of the corresponding master station and slave station in real space is set as a virtual placement point, and the calculation model is changed.

[0165] Using the modified calculation model, a master station with which the slave station can communicate with good quality wireless communication is estimated from the position of the transmission point in the computer resources, and control is implemented to allow the slave station to communicate with the corresponding master station.

[0166] According to this embodiment, the master station communicating with the slave station can be changed in response to dynamic deterioration in wireless communication quality that occurs within the service area, which has the effect of restoring the communication quality of the slave station in real time. Compared to the embodiment of Figure 20, this has the effect of further improving the communication reliability and throughput of a wireless network consisting of multiple master stations and slave stations.

[0167] According to the above-described embodiment, an electromagnetic field calculation model for estimating communication quality within a service area providing wireless communication can be constructed within a computer resource using actual measurement data within the service area. This makes it possible to generate an electromagnetic wave calculation model that faithfully reproduces the actual radio wave environment at the site where wireless communication is performed, and to modify the electromagnetic field calculation model within the computer resource in response to environmental changes at the wireless communication site. Furthermore, it is possible to improve the estimation accuracy of wireless communication performance within a wireless communication service area, thereby realizing real-time communication performance understanding. Furthermore, because the electromagnetic field calculation model constructed within the computer resource can be constructed on-site, it has the effect of reducing the wireless engineering costs required for customers to install wireless communication systems.

[0168] According to the above embodiment, it is possible to simulate a radio wave environment with high accuracy within computer resources, thereby reducing the amount of work required in the real space, reducing energy consumption and carbon emissions, preventing global warming, and contributing to the realization of a sustainable society. [Explanation of symbols]

[0169] 1...room 2...Window 3...Door 4…Shelf 5...Table 6...Measured electromagnetic field strength distribution 7...Mobile radio wave measuring instrument 8… 9...Moving obstacles 10...Radio 11...Measurement point 12...Polygon 27...High frequency cable 28...Low frequency cable 29...Arrival vector 30...Virtual cube 31...Slave unit 32...Master unit 37...Regular octahedron 38...Regular dodecahedron 106…Estimated electromagnetic field strength distribution 110...Transmission point 118...Transmission point 119…Reception point 121...Direction of radio wave arrival 122...Direction corresponding to the direction of arrival

Claims

1. When a structural model of an electromagnetic wave scatterer is constructed in a computer resource and the characteristics of an electromagnetic field are calculated using the structural model and a ray simulating radio waves traveling in a straight line through real space, The state of the polygons constituting the structural model is corrected using electromagnetic wave vector measurement data in real space, using measured values ​​of the intensity of radio waves in the real space and the direction of arrival of the radio waves, changing at least one of the normal direction of a polygon in the structural model of the electromagnetic wave scatterer and the positions of points in the point cloud constituting the polygon so that the measured electromagnetic field intensity distribution actually measured in the real space approaches the estimated electromagnetic field intensity distribution calculated using the structural model; Radio wave environment evaluation method.

2. The structural model is constructed as a collection of polygons having vertices that are a plurality of points in a point cloud generated from distance measurement data consisting of directions and distances obtained at a plurality of points in real space. The radio wave environment evaluation method according to claim 1.

3. modifying the direction of the normals of said polygons; The radio wave environment evaluation method according to claim 1.

4. modifying the state of the polygon by moving the coordinates of the vertices of the polygon; The radio wave environment evaluation method according to claim 1.

5. identifying, as an abnormality location, a location in the structural model corresponding to a location where a difference between an actual measured electric field intensity based on the electromagnetic wave vector measurement data and an estimated electric field intensity calculated using the structural model is equal to or greater than a predetermined value; a polygon that faces the abnormal location and exists in a direction corresponding to the direction of arrival of the radio waves to the abnormal location is designated as a specific polygon, and a state of at least one polygon among the specific polygon and a plurality of polygons that share vertices with the specific polygon is corrected; The radio wave environment evaluation method according to claim 1.

6. determining the specific polygon based on the direction of arrival of a received wave measured at a location in real space corresponding to the abnormal location; The radio wave environment evaluation method according to claim 5.

7. When correcting the state of the polygon, a polygon that shares a vertex with the specific polygon is identified as a replacement candidate polygon; If the estimated electric field intensity is smaller than the actually measured electric field intensity by a predetermined amount or more at the abnormal location, a substitute candidate polygon is selected from the substitute candidate polygons with which a ray having an intensity greater than that of the ray colliding with the specific polygon is colliding, and the specific polygon and the substitute candidate polygon are corrected so that the ray colliding with the selected substitute candidate polygon is directed toward the abnormal location; If the estimated electric field intensity is greater than the actually measured electric field intensity by a predetermined amount or more at the abnormal location, a substitute candidate polygon that is colliding with a ray having an intensity lower than that of the ray colliding with the specific polygon is selected from the substitute candidate polygons, and the specific polygon and the substitute candidate polygon are corrected so that the ray colliding with the selected substitute candidate polygon is directed toward the abnormal location. The radio wave environment evaluation method according to claim 5.

8. The direction of arrival of the received wave is measured using information on the relative phases of the received waves received by a plurality of antennas distributed in three-dimensional space and the spatial positions of the antennas. The radio wave environment evaluation method according to claim 6.

9. A set of two antennas that are uniformly distributed in three-dimensional space and orthogonal to each other in space is used to measure the direction of arrival and polarization of the received wave. The radio wave environment evaluation method according to claim 8.

10. The direction of arrival of received waves is measured using antennas installed on each face of a virtual regular hexahedron, regular octahedron, or regular dodecahedron. The radio wave environment evaluation method according to claim 8.

11. The system includes a model generation unit, an electric field calculation unit, and a polygon correction unit, the model generation unit constructs, within computer resources, a structural model of an electromagnetic wave scatterer existing in real space; the electric field calculation unit performs a ray tracing calculation using the structural model, estimates an electric field intensity in a real space, and calculates an estimated electric field intensity; the polygon correction unit identifies polygons that need to be corrected among the polygons that configure the structural model based on the arrival direction of electromagnetic waves actually measured in real space, and corrects them, Further, an error detection unit is provided, The error detection unit extracts, as an abnormality location, a location where a difference between an actual electric field strength measured in a real space and the estimated electric field strength is equal to or greater than a predetermined value, the polygon correction unit identifies a polygon that needs to be corrected from among a specific polygon that exists in a direction corresponding to the arrival direction of the electromagnetic waves and polygons that share a vertex with the specific polygon, based on the arrival direction of the electromagnetic waves actually measured at a location in real space that corresponds to the abnormal location; using measured values ​​of the intensity of radio waves in the real space and the direction of arrival of the radio waves, changing at least one of the normal direction of a polygon in the structural model of the electromagnetic wave scatterer and the positions of points in the point cloud constituting the polygon so that the measured electromagnetic field intensity distribution actually measured in the real space approaches the estimated electromagnetic field intensity distribution calculated using the structural model; Wireless communication characteristics evaluation system.

12. the polygon correction unit performs the correction by changing the coordinates of the vertices of the polygon. The wireless communication characteristic evaluation system according to claim 11.

13. the polygon correction unit performs the correction by changing the normal of the polygon; The wireless communication characteristic evaluation system according to claim 11.

14. The polygon correction unit Identifying polygons that share vertices with the specific polygon; If the estimated electric field strength is smaller than the actually measured electric field strength by a predetermined amount or more at the abnormal location, a polygon that is colliding with a ray having a greater intensity than a ray colliding with a polygon in the direction of arrival of the electromagnetic wave is selected from the identified polygons, and the polygon is corrected so that the ray colliding with the selected polygon is directed toward the abnormal location; If the estimated electric field strength is greater than the actually measured electric field strength by a predetermined amount or more at the abnormal location, a polygon that is colliding with a ray having an intensity smaller than that of a ray colliding with a polygon in the direction of arrival of the electromagnetic wave is selected from the identified polygons, and the polygon is corrected so that the ray colliding with the selected polygon is directed toward the abnormal location. The wireless communication characteristic evaluation system according to claim 11.

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