KR100948186B1 - Device for generating electromagnetic wave propagation model using 3-d ray tracing, method for generating electromagnetic wave propagation model using 3-d ray tracing, storage media recording program for method execution in computer for generating electromagnetic wave propagation model using 3-d ray tracing - Google Patents

Abstract

The present invention relates to a method of generating a propagation model by tracking a propagation path.

According to the present invention, three-dimensional building information of the target area of the radio wave model is read and a transmission point is set. Find the point of symmetry with respect to the building surface searched from the transmission point, and generate a three-dimensional ray tube generated by the reflected radio waves. It produces a three-dimensional ray tube generated by radio waves diffracted by the building surface edges searched from the transmission point. Repeating the generation of the three-dimensional ray tube by the reflection and diffraction with respect to the building surface included in or intersecting the area of the three-dimensional ray tube generated by the reflection and diffraction and being searched at the symmetry point or building surface edge. A 3D ray tube is connected with the 3D ray tube.

Therefore, it is possible to generate an accurate propagation model at the position where the actual radio wave is received.

Ray tube, imaging dots, diffraction

Description

DEVICE FOR GENERATING ELECTROMAGNETIC WAVE PROPAGATION MODEL USING 3-D RAY TRACING, METHOD FOR GENERATING ELECTROMAGNETIC WAVE PROPAGATION MODEL USING 3-D RAY TRACING, STORAGE MEDIA RECORDING PROGRAM FOR METHOD EXECUTION IN COMPUTER FOR GENERATING ELECTROMAGNETIC WAVE PROPAGATION MODEL USING 3-D RAY TRACING}

1 is an exemplary view of finding a propagation path using a conventional ray tube method.

Figure 2 shows a three-dimensional ray tube formed by the radio waves reflected in the building surface in the three-dimensional ray tracing method according to an embodiment of the present invention.

Figure 3 shows a three-dimensional ray tube formed by radio waves diffractive at the corner of the building in the three-dimensional ray tracing method according to an embodiment of the present invention.

4 illustrates a three-dimensional ray tube in which a ray tube formed by reflection according to an embodiment of the present invention is reflected by another building surface again.

5 is a view showing a three-dimensional ray tube formed by diffraction at the edge of the other building surface in the three-dimensional ray tube formed by the propagation path by the reflection according to an embodiment of the present invention.

6 is a block diagram showing the configuration of a three-dimensional propagation model generation device according to an embodiment of the present invention.

7 is a flowchart illustrating a method for finding a propagation path constituting a propagation model according to an embodiment of the present invention.

8 is a flowchart illustrating a method of generating a propagation model at a reception point according to an embodiment of the present invention.

9 is a view of a three-dimensional ray tube passing through the receiving point in the propagation model generation method according to an embodiment of the present invention.

The present invention relates to a method for forming a propagation model, and in particular, the present invention relates to a method for analyzing a propagation path using a three-dimensional ray tracing method and forming a propagation model accordingly.

Recently, due to the increasing demand for personal communication services, interest in the radio environment in urban areas is increasing. The urban radio environment is a small cell with a service radius of less than 1 km. Small cells include micro cells and pico cells, which, unlike macro cells with a relatively large service radius, receive power greatly depending on the radio environment between the base station and the mobile station. Therefore, precise analysis is required for accurate prediction of the received power, and the necessity of a propagation model formed based on the propagation path is more urgent.

Conventional methods for obtaining a propagation model include a statistical method of obtaining statistics based on experimental results and a computer prediction method of obtaining a propagation model by predicting a propagation path through a computer based on a theory. The method of obtaining a propagation model by a statistical method has an advantage of easily obtaining prediction values, but there is a limit in obtaining an accurate propagation model since the distribution of the actual terrain and buildings is not taken into account. On the other hand, the computer prediction method has the advantage of obtaining a very accurate propagation model because the actual building data is used to calculate all possible propagation paths and obtain the result. However, there are limitations in predicting all possible propagation paths, and it takes a long time to predict as many propagation paths as possible.

Computer prediction methods can be divided into two types according to the method of tracking propagation paths. The first method is to identify the point where the straight line meets the building surface by generating a semi-infinite straight line in all directions from the position of the transmitting antenna. Although not exactly the same as the actual propagation phenomenon, the reason for using a straight line is that if the area of the building surface is very large compared to the wavelength of the radio wave, the area affected by diffraction is relatively narrow and can be ignored. When the radio waves emitted from the building surface and the transmitting antenna meet, a straight line corresponding to the reflected wave can be made according to the angle of the building surface and the straight line, and the generated straight line meets the building surface again. Check for passing through the point. If the measurement point is included in the path of the radio wave, the attenuation of the radio wave by the distance from the transmission point to the measurement point, the attenuation due to reflection on the wall, etc. are calculated to obtain a prediction result. In this way, the accuracy of calculating the propagation model depends on the number of infinite straight lines. The more infinite straight lines you use, the better the accuracy of the propagation model, but the more time it takes to calculate the propagation model. The second method is to solve this problem, and to form a ray tube (ray tube) generated by the reflected straight line by radiating only one straight line on the building surface visible from the transmitting antenna. A ray tube is a bundle of a plurality of rays, in which all rays in the same ray tube have the same propagation path value.

1 illustrates an application for finding a propagation path using a conventional ray tube method. After firing a plurality of radio waves at equal intervals from the transmission point, each radio wave is traced to form a ray tube of a set of paths formed by the plurality of radio waves. The ray tube reaching the receiving point is found among the ray tubes thus formed. All the paths of the formed ray tubes have the same propagation path values. First, the position of the radio wave transmission antenna becomes a transmission point, and the building surface seen from the transmission point is found. The image point I1 whose transmission point is symmetric with respect to the building surface # 1 is found, and then the image point I2 which is symmetrical with respect to the building surface # 2 is found from the image point I1. Find the image point I3 in the same way. The position of the image points I1 to I3 is found to find a path on which the radio wave emitted from the transmission point is reflected. At this time, the propagation path range angle Φ 1 -Φ 3 is considered. Parameters of the position of the image points I1-I3, the building surface # 1- # 3 visible from the transmission point, and the propagation path range angle Φ1-Φ3 form the ray tube due to the reflected radio waves. This method determines the speed, accuracy, and complexity of calculating the propagation path depending on which building surface is visible from the transmit antenna location. However, in this method, only two-dimensional information corresponding to the vertex of the horizontal plane is used among the information related to the plane and the edge of the building to find the building plane visible from the transmission point. Therefore, there is a problem that propagation in the direction perpendicular to the ground cannot be considered. An error occurs between a ray tube, which is a set of propagation paths reaching the actual reception point R, and a ray tube at the reception point R according to the path of the radio wave predicted using a computer.

An object of the present invention is to provide a propagation path tracking method for constructing an accurate propagation model by predicting an actual propagation path.

In order to solve the above-mentioned problems, a method of generating a propagation model by tracking a three-dimensional ray according to a feature of the present invention,

a) reading 3D building information of a target area of the propagation model and setting a transmission point; b) finding a symmetry point with respect to the building surface searched from the transmission point and generating a three-dimensional ray tube generated by the reflected radio waves; c) generating a three-dimensional ray tube generated by radio waves diffracted by building surface edges searched from the transmission point; d) repeating steps b) and c) for the building surface included in or intersecting the area of the three-dimensional ray tube generated in steps b) and c and searched for at the symmetry point or building surface edge. Coupling a dimensional ray tube with the three dimensional ray tube.

In addition, a recording medium storing a program according to a feature of the present invention,

a) reading 3D building information of a target area of the propagation model and setting a transmission point; b) finding a symmetry point with respect to the building surface searched from the transmission point and generating a three-dimensional ray tube generated by the reflected radio waves; c) generating a three-dimensional ray tube generated by radio waves diffracted by building surface edges searched from the transmission point; d) repeating steps b) and c) for the building surface included in or intersecting the area of the three-dimensional ray tube generated in steps b) and c and searched for at the symmetry point or building surface edge. Coupling the dimensional ray tube with the three dimensional ray tube is performed on a computer.

In addition, the three-dimensional propagation model generation device according to a feature of the present invention,

An information input unit configured to receive terrain information on a specific region and information on radio waves used for transmission and reception;

A terrain generation unit configured to generate virtual terrain by receiving terrain information about the area;

A radio wave tracking unit configured to three-dimensionally track radio waves emitted from the transmission position to generate a three-dimensional ray tube;

The 3D ray tube receives the 3D ray tube from the radio wave tracking unit, calculates the path length of the 3D ray tube, compares the critical distance with the path length, and passes the receiving position among the 3D ray tubes. A control unit; And

And a propagation model generator for selecting a three-dimensional ray tube passing through a reception position among the three-dimensional ray tubes and calculating an energy intensity of a radio wave detected at the reception position.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Now, a method of generating a propagation model by tracking a propagation path according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows a three-dimensional ray tube formed by the radio waves reflected in the building surface in the three-dimensional ray tracing method according to an embodiment of the present invention. At this time, it is assumed that the shape of the building is a cuboid. The same is true in the examples below.

As shown in FIG. 2, the three-dimensional ray tube has the shape of a pyramid. The vertex of the pyramid is determined by the position of the transmission point. The position where the position A1 of the transmission point is formed by plane symmetry with respect to the building surface 100 seen from the position A1 of the transmission point becomes the vertex B of the pyramid. This is called image point in propagation theory. The vertical lines connecting the vertices B and the vertices C1, C2, C3, and C4 of the building surface 100 become corners of the pyramid. The pyramid-shaped ray tube thus formed may be identical to the entire set of paths through which the radio wave emitted from the transmission point A1 is reflected by the building surface 100.

Figure 3 shows a three-dimensional ray tube formed by radio waves diffractive at the corner of the building in the three-dimensional ray tracing method according to an embodiment of the present invention.

As shown in FIG. 3, diffraction of radio waves may occur at the corners of the building. Diffraction of radio waves is an important consideration to consider with reflection of radio waves in estimating propagation paths.

The radio wave emitted from the transmission point A2 causes diffraction at the diffraction point D where the radio wave meets the corner a-a 'when the building meets the corner a-a'. The angle θ1 formed between the position A2 of the transmission point and the diffraction point D is maintained, and at the diffraction point D, radio waves are radiated in all open directions. Assuming that the radio waves causing diffraction at the diffraction point (D) do not pass through the building surface adjacent to the edge (a-a ') and penetrate into the building, the diffraction point (D) is defined around the building surfaces (200, 250). It can be seen that the radio wave is diffracted from the building surface (200, 250). Thus, a three-dimensional ray tube is formed, consisting of diffracted radio waves radiated with two building surfaces 200 and 250 adjacent to edge a-a 'and an angle θ1. These three-dimensional ray tubes may vary in shape depending on which diffraction point the radio waves cause at the corners a-a '. 3 is a plan view from above of the formed three-dimensional ray tube.

As described above, in the three-dimensional ray tracing method according to the embodiment of the present invention, the vertex B of the ray tube formed by the reflection shown in FIGS. 2 and 3 and the vertex D of the ray tube formed by diffraction are as follows. It can be a starting point to form a ray tube. That is, it is possible to form a three-dimensional ray tube that reflects or diffracts again from the point of symmetry of the vertices B, D with respect to the building surface included in the region of the pyramidal ray tube including the vertices B, D.

4 illustrates a three-dimensional ray tube in which a ray tube formed by reflection according to an embodiment of the present invention is reflected by another building surface again.

As shown in FIG. 4, the symmetry point of the transmission point with respect to the building surface 300 visible at the transmission point A3 becomes the vertex E1 of the three-dimensional ray tube. Radio waves are emitted from the transmission point A3 and the radio waves reflected by the building surface 300 form the first three-dimensional ray tube. The radio waves are reflected back at the building surface 350 contained within the first three-dimensional ray tube region. In the embodiment of the present invention, the building surface 350 is assumed to include the entire area in the first three-dimensional ray tube area. The point E2 where the vertex E1 is symmetric about the building surface 300 becomes the vertex of the three-dimensional ray tube again. At this time, the vertex E1 serves as a transmission point. That is, the source of emitting radio waves and the symmetry point E2 become the vertices E2 of the new three-dimensional ray tube formed by reflecting the reflected radio wave again, and the second three-dimensional ray tube is formed. By repeating this process to generate a three-dimensional ray tube to obtain all possible propagation paths, it may be the same as the result of measuring the propagation path by firing the actual radio waves. In addition, since the energy is attenuated when the radio waves propagate through each of the three-dimensional ray tube, it is possible to determine a constant energy intensity to obtain a path length of radio waves having an intensity less than or equal to this threshold value. If the path length exceeds the threshold, the three-dimensional ray tube progression stops.

5 is a view showing a three-dimensional ray tube formed by diffraction at the edge of the other building surface in the three-dimensional ray tube formed by the propagation path by the reflection according to an embodiment of the present invention.

As shown in FIG. 5, radio waves are emitted at the transmission point and the symmetry point F1 of the transmission point with respect to the building surface 400 becomes the vertex of the three-dimensional ray tube. When one of the reflected radio waves constituting the 3D ray tube passes through the edge b-b 'of the building surface 450, a diffraction wave having an angle ω is formed at the point p at which the radio wave meets the edge. As described with reference to FIG. 3, the diffraction wave forms a three-dimensional ray tube by two building surfaces adjacent to an edge. The three-dimensional ray tube generated by the diffraction wave may be diffracted or reflected again by another building surface to generate the three-dimensional ray tube. When reflected again, the diffraction point can be the vertex of the ray tube produced by the reflection that is the point symmetrical with respect to the other building surface being reflected.

As such, the three-dimensional propagation model generation method according to the embodiment of the present invention may provide a more accurate propagation model in consideration of the vertical component.

Hereinafter, a radio wave model generating apparatus according to an embodiment of the present invention will be described.

6 is a block diagram briefly illustrating a configuration of an apparatus for generating a propagation model according to an exemplary embodiment of the present invention.

As shown in FIG. 6, the apparatus for generating a radio wave model according to an exemplary embodiment of the present invention includes an information input unit 100, a terrain generator 200, a radio tracker 300, a radio wave model generator 500, and a controller ( 400).

The information input unit 100 receives terrain information such as the number, shape, and location of buildings distributed in an area where a radio wave model is to be generated. Since the terrain information is changed in the radio environment in the unit of a micro cell or pico cell according to the position at which the radio wave is transmitted, new terrain information is input according to the transmission position. In addition, the information input unit 100 may receive other information required for the radio wave model, such as a frequency band and antenna characteristics of radio waves propagated in the radio wave model target region.

The terrain generation unit 200 generates a virtual terrain in three dimensions based on the terrain information input to the information input unit 100. Create three-dimensional terrain using information about the location between buildings, the height, shape of each building, the road, and the altitude of the radio model area.

When the transmission position is set, the radio tracking unit 300 tracks the radio waves emitted from the transmission position in three dimensions to generate a three-dimensional ray tube in which the radio waves are reflected on a building surface or diffracted by an edge. The propagation tracking unit 300 may include a database capable of storing the generated 3D ray tube. The propagation tracking unit 300 may transmit the 3D ray tube stored in the database to the control unit 400 or the propagation model generator 500.

The controller 400 receives the information input from the information input unit 100 and the terrain generation unit 200 and the terrain of the propagation model target region. In addition, the 3D ray tube is received from the radio wave tracking unit 300 and the path of the 3D ray tube generated by the radio wave tracking unit 300 is calculated and compared with a threshold. The threshold value means a propagation path length in which a propagation energy has a value below a specific value in generating a 3D propagation model. In generating a three-dimensional propagation model, a radio wave having energy below a certain value is difficult to be detected at the receiving side, and it takes more time if it is calculated to generate the three-dimensional propagation model including this propagation. Therefore, when the propagation path length is greater than or equal to the threshold, the control unit 400 may be configured to a building surface other than the building surface which is currently performing the 3D ray tube generation operation among the plurality of building surfaces visible from the transmission position to the radio tracking unit 300. Can generate a three-dimensional ray tube for. In addition, the controller 400 may set a transmission position and a reception position of the radio wave. If the propagation path length is less than the threshold, the control unit 400 may continue the 3D ray tube generation operation of the propagation tracking unit 300.

The propagation model generator 500 may generate a 3D propagation model by receiving a 3D ray tube and preset reception position information generated by the propagation tracker 300. The path length of the selected three-dimensional ray tube is calculated, and the propagation attenuation along the path is calculated to calculate the energy intensity of the radio wave detected at the receiving position. If this operation is performed for all three-dimensional ray tubes passing through the receiving position, and the result is summed, the energy intensity of the radio wave detected at the receiving position can be obtained, and if the receiving position is changed and repeatedly performed in the target area, An overall three-dimensional propagation model can be generated.

7 is a flowchart illustrating a method for finding a propagation path constituting a 3D propagation model according to an embodiment of the present invention.

As shown in FIG. 7, first, three-dimensional building information of an area to construct a propagation model is read (S100). Buildings can be organized in a simple cube shape for ease of prediction. In the fourth embodiment of the present invention, it is assumed to be a cuboid. In order to calculate a propagation model, a transmission point is set, and numerical values, such as the position of the transmission point and the characteristics of the antenna that emits radio waves at the transmission point, are input (S200). The building surface visible from the transmission point is searched and a building surface for emitting radio waves is first selected from the found building surfaces (S300). Find and set the symmetry point of the transmission point for the selected building surface (S400). Each vertex of the building surface is connected in a half straight line from the symmetry point (S410). Then, a three-dimensional ray tube formed by the reflected radio waves is formed, and the symmetry point may be a vertex of the three-dimensional ray tube, and a triangle formed by the symmetry point and each corner of the building surface may have a pyramidal shape. The three-dimensional ray tube thus formed is stored (S420). Again, this propagation reduces energy as it travels through the ray tube, so that a constant propagation path length is set as a threshold, so that a ray tube formed by propagation above the threshold can not be generated. Therefore, each time the above operation is repeated, the length of the propagation paths formed by connecting the stored 3D ray tubes to each other is compared with a threshold (S430). If it is below the threshold, the symmetry point can be a source for forming another three-dimensional ray tube. That is, it plays a role of emitting radio waves like a transmission point. Therefore, the operation of forming the three-dimensional ray tube by reflection or diffraction is repeated with respect to another building surface which is included in the region of the three-dimensional ray tube or meets the region of the three-dimensional ray tube and is visible at the symmetry point. If it is above the threshold, three-dimensional ray tube generation starts for the other building surface found at that transmission point. The 3D ray tube generation method for the other building surface may be the same as the method described so far.

When the radio wave emitted from the first transmission point causes diffraction at the corner of the building, the angle formed by the vertical line at the corner is formed by a straight line connecting the point where the radio wave is emitted and an arbitrary point constituting the corner where the diffraction occurs (S500). ). The diffraction wave maintains this angle with the vertical line of the edge at the edge and causes diffraction. It forms a three-dimensional ray tube having a boundary between two building surfaces adjacent to an edge, and composed of a set of diffraction waves formed at a constant angle with a vertical line at the edge. In this manner, the entire three-dimensional ray tube by diffraction may be generated for all points constituting the edge (S510). The generated three-dimensional ray tube is stored (S520). Even in the case of the entire three-dimensional ray tube by diffraction, since the radio waves propagate through the ray tube, the energy is attenuated. The three-dimensional ray tube to be formed can be set not to be generated. Therefore, each time the above operation is repeated, the propagation path length of the 3D ray tube connected to the threshold is compared (S530). The edges of the building surface where diffraction occurs can, like the point of symmetry, be a source for creating other three-dimensional ray tubes. Thus, if the propagation path length is below the threshold, diffraction occurs at the three-dimensional ray tube or edge by reflection to the building surface that includes or meets the three-dimensional ray tube region generated at the edge where diffraction occurs and is seen at the diffraction point. The operation of generating a three-dimensional ray tube by waves is repeated. On the other hand, if it is above the threshold, three-dimensional ray tube generation starts for the other building surface found at the corresponding transmission point. The 3D ray tube generation method for the other building surface may be the same as the method described so far.

As such, when the three-dimensional ray tube is generated, stored, and connected to each other, a more accurate result can be obtained because the vertical component of the ground is considered in estimating the path of the radio wave emitted from the transmitting antenna. The three-dimensional ray tube formed by the reflected radio waves can produce three-dimensional ray tubes by diffraction at different building surfaces. In contrast, a three-dimensional ray tube formed by diffraction can produce a three-dimensional ray tube by reflection in another building surface. As described above, the combination of the three-dimensional ray tube by the plurality of reflections and the three-dimensional ray tube by the diffraction can predict the path of the radio wave emitted from the transmission point similarly to the reality.

Hereinafter, a method of generating a propagation model will be described with reference to FIGS. 8 and 9.

8 is a flowchart illustrating a method of generating a propagation model at a reception point according to an embodiment of the present invention. 9 is a view of a three-dimensional ray tube passing through the receiving point in the propagation model generation method according to an embodiment of the present invention.

), 대칭점의 위치 벡터(

), 건물면의 법선 벡터(

) 및 3차원 레이 튜브 경계를 이루는 옆면의 법선 벡터(

,i=1,2,3,4)를 이용하여 찾을 수 있다. [수학식 1] 및 [수학식 2]의 조건을 만족하는 대칭점의 위치 벡터, 건물면의 법석 벡터 및 3차원 레이 튜브 옆면의 법석 벡터로 특정되는 3차원 레이 튜브를 찾는다.As shown in FIG. 8, a reception point is set in a cell in which a propagation model is to be generated (S600). The 3D ray tube passing through the receiving point is detected from the formed plurality of 3D ray tubes (S610). At this time, the three-dimensional ray tube passing through the receiving point can be found using the method shown in FIG. The position vector of the receiving point (

), The position vector of the symmetry point (

), The normal vector of the building surface

) And the side normal vector (

, i = 1,2,3,4). The 3D ray tube identified by the position vector of the symmetry point which satisfy | fills the conditions of Formula (1) and (Equation 2), the rule vector of a building surface, and the rule vector of the side surface of a 3D ray tube is found.

When the 3D ray tube passing through the receiving point is found by using Equations 1 and 2, the propagation path is calculated from the transmitting point to the receiving point in the 3D ray tube (S620). If the three-dimensional coordinates of the reception point is (xr, yr, zr) and the three-dimensional coordinates of the symmetry point are (xs, ys, zs), the propagation path length R can be obtained by Equation 3.

Propagation attenuation may be calculated using the propagation path length R and the reflection coefficient of the building surface (S630). Propagation attenuation can be calculated in the same way for all three-dimensional ray tubes passing through the receiving point. It is determined whether the propagation attenuation calculation has been completed for all detected 3D ray tubes (S640). As a result of the determination, if there is a three-dimensional ray tube to calculate the attenuation, the process is repeated from the beginning. Otherwise, the radio attenuation calculation ends. After completing the attenuation calculation, the strength of the received radio wave may be estimated based on the sum of all radio waves reaching the reception point (S650). The radio wave model can be completed by changing the position of the reception point in the region of the radio wave model and repeating such an operation.

As such, the propagation attenuation of all three-dimensional ray tubes passing through the receiving point may be very similar to the result obtained by measuring the actual propagation path. In addition, it is apparent to those skilled in the art that the three-dimensional ray tube by diffraction can find the three-dimensional ray tube passing through the reception point to obtain radio wave attenuation.

 The embodiments of the present invention described above are not implemented only by the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded. From the description of the embodiments described above it can be easily implemented by those skilled in the art.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

According to the above configuration, the error compared to the result of measuring the radio wave attenuation directly at the position where the radio wave is received through the experiment can be greatly reduced. Therefore, the effect of obtaining a more accurate propagation model can be expected at the point where radio waves are received.

Claims (16)

In the method for generating a propagation model by tracking the propagation path, a) reading 3D building information of a target area of the propagation model and setting a transmission point; b) finding a symmetry point with respect to the building surface searched from the transmission point, and generating a three-dimensional ray tube generated by the reflected radio waves, c) generating a three-dimensional ray tube generated by radio waves diffracted by the building surface edges searched from the transmission point, and d) repeating steps b) and c) for the building surface included in or intersecting the area of the three-dimensional ray tube generated in steps b) and c and searched for at the symmetry point or building surface edge. Connecting a dimensional ray tube with the three-dimensional ray tube. The method of claim 1, Repeating step d) a predetermined number of times, wherein the predetermined number of times is set to a number of times of repeating while the total path length generated by reflection or diffraction is less than a threshold value. The method of claim 2, The threshold is set in consideration of the path length having a predetermined energy or less in consideration of the energy of the radio wave decreases as the radio wave repeats reflection or diffraction. The method of claim 1, Step a) is Connecting each vertex of the building surface in a straight line from the symmetry point; And And generating the three-dimensional ray tube comprising a plurality of side surfaces having a triangle as an edge and comprising a triangle formed by the symmetry point and the corner of the building surface. The method of claim 1, Step b), Iii) calculating an angle formed by a straight line connecting the transmission point and any diffraction point of the edge of the building surface and a straight line passing through the transmission point and parallel to the ground; Ii) generating a diffractive three-dimensional ray tube characterized by a set of a plurality of semi-linear lines having said angle at said diffraction point and located between both building surfaces adjacent said edge; And Generating the propagation model comprising repeating steps iii) and ii) for the other diffraction points of the edges to generate the three-dimensional ray tube specified by the set of diffractive three-dimensional ray tubes formed at the node. Way. The method of claim 1, And storing the plurality of three-dimensional ray tubes connected in step d). The method of claim 6, And setting a receiving point in a target area of the propagation model and finding a 3D ray tube passing through the receiving point among the stored plurality of 3D ray tubes. The method of claim 7, wherein Calculating a radio wave attenuation using a three-dimensional ray tube passing through the reception point, and predicting the intensity of received radio waves at the reception point. The method of claim 8, Set a different receiving point in the propagation model generation area to find a three-dimensional ray tube passing through the receiving point among the stored plurality of three-dimensional ray tubes, and calculate the radio wave attenuation using the third-order ray tube to calculate the receiving point. A method of generating a propagation model, repeating the step of predicting the strength of a received radio wave in. A storage medium having recorded thereon a program for causing a method according to any one of claims 1 to 9 to be executed on a computer. An information input unit configured to receive terrain information on a specific region and information on radio waves used for transmission and reception; A terrain generation unit configured to generate virtual terrain by receiving terrain information about the area; A radio wave tracking unit configured to three-dimensionally track radio waves emitted from the transmission position to generate a three-dimensional ray tube; The 3D ray tube receives the 3D ray tube from the radio wave tracking unit, calculates the path length of the 3D ray tube, compares the critical distance with the path length, and passes the receiving position among the 3D ray tubes. A control unit; And And a propagation model generator for selecting a 3D ray tube passing through a reception position among the 3D ray tubes and calculating an energy intensity of radio waves detected at the reception position. The method of claim 11, The propagation tracking unit propagation model generating device including a database for storing the generated three-dimensional ray tube. The method of claim 11, In the control unit, And the critical distance is a propagation path length in which the energy of the radio wave has a value less than or equal to a predetermined value. The method of claim 11, The control unit, And propagating the three-dimensional ray tube when the path length of the three-dimensional ray tube reaches the critical distance, and generating a three-dimensional ray tube for another building surface visible from the transmission position. The method of claim 11, The propagation model generation unit, Propagation model generation device for obtaining the energy attenuation of the three-dimensional ray tube containing the receiving position, and generating the three-dimensional propagation model with the total energy of the three-dimensional ray tube. The method of claim 11, The radio wave tracking unit, And generating a three-dimensional ray tube formed by the radio waves by tracking a propagation path by reflection or diffraction of radio waves on a building surface detected from the transmission position in the three-dimensional propagation model target region.

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