WO2007035052A1 - 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

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 Download PDF

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Publication number
WO2007035052A1
WO2007035052A1 PCT/KR2006/003767 KR2006003767W WO2007035052A1 WO 2007035052 A1 WO2007035052 A1 WO 2007035052A1 KR 2006003767 W KR2006003767 W KR 2006003767W WO 2007035052 A1 WO2007035052 A1 WO 2007035052A1
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WO
WIPO (PCT)
Prior art keywords
ray tube
electromagnetic wave
point
propagation model
propagation
Prior art date
Application number
PCT/KR2006/003767
Other languages
French (fr)
Inventor
Yong-Bae Park
Haeng-Seon Lee
Hyun-Meen Jung
Original Assignee
Kt Corporation
Chun, Wan-Jong
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Publication date
Application filed by Kt Corporation, Chun, Wan-Jong filed Critical Kt Corporation
Publication of WO2007035052A1 publication Critical patent/WO2007035052A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3911—Fading models or fading generators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/18—Network planning tools
    • H04W16/20—Network planning tools for indoor coverage or short range network deployment

Definitions

  • the present invention relates to a propagation model generating method, and in particular, it relates to a method for analyzing a propagation path by using a 3-dimensional ray tracking method, and generating a corresponding propagation model.
  • the urban electromagnetic wave environment represents a small cell having a service radius within 1 km.
  • the small cell includes a micro cell and a pico cell, and the received power of the cells greatly depends on the electromagnetic wave environment between the base station and the mobile station differing from the macro cell having a relatively big service radius. Therefore, in order to estimate the accurate received power, a precise analysis is required, and a propagation model generated based on the corresponding propagation path is further needed.
  • the conventional method for generating the propagation model includes a statistical method for generating a propagation model by acquiring statistics based on the test result and a computer estimation method for generating a propagation model by estimating a computerized propagation path based on theoretic schemes.
  • the method for generating a propagation model through statistics has an advantage in easily acquiring estimates, but has a problem of acquiring the accurate propagation model since it considers no real topography and building arrangement.
  • the computerized estimation method has an advantage in acquiring a very accurate propagation model by computing available propagation paths by using the real building data.
  • the computerized estimation method has a problem of estimating all the available propagation paths and a drawback of spending much time in estimating all the propagation paths.
  • the computerized estimation method is classified as two methods depending on the propagation path tracking method.
  • the first method is to generate half infinite lines in all directions at the location of a transmit antenna and check the point where the straight line meets the building surface.
  • the reason for using the straight lines is, though not the same as the phenomenon of the actual propagation phenomenon, that the area influenced by diffraction is relatively narrow and can be neglected when the area of the building surface is very greater than the wavelength of the corresponding electromagnetic wave.
  • a straight line corresponding to the reflected wave can be generated according to the angle between the building surface and the straight line when the building surface and the electromagnetic wave radiated from the transmit antenna meet, and it is determined whether the above-noted straight line meets the building surface again and the straight line is passed through the point that corresponds to the measurement point of the propagation model.
  • estimation results are found by calculating the attenuation caused by the distance from the transmission point to the measurement point and the attenuation caused by the reflection on the wall surface.
  • the calculation of the actual propagation model through the above-described methods generates different accuracy depending on the number of infinite straight lines.
  • the second method has improved the problem, which forms a ray tube generated by a reflected straight line by radiating one straight line on the building surface viewed at the transmit antenna.
  • the ray tube represents a pack of a plurality of rays, and all the rays in the same ray tube have the same propagation path value.
  • FIG. 1 shows a conventional method for finding a propagation path by using a ray tube.
  • a plurality of electromagnetic waves is applied at regular intervals from a transmission point, each of the electromagnetic waves is tracked, and a set of paths formed by a plurality of electromagnetic waves configures the ray tube.
  • a ray tube reaching the receiving point is found. All the paths of the formed ray tube have the same propagation path value.
  • the location for the electromagnetic wave transmit antenna is given as a transmission point, and the building surface viewed at the transmission point is found.
  • An image point (11) at which the transmission point is symmetric with respect to the building surface (#1) is found, and an image point (I2) symmetric with respect to the building surface (#2) is found from the image point (11).
  • An image point (I3) is found in a like manner.
  • a path on which the electromagnetic wave provided from the transmission point is reflected is found by finding the location of the image point (11-13).
  • range angles ( ⁇ 1- ⁇ 3) of path available for propagation are considered.
  • the ray tube caused by the reflected electromagnetic wave is formed by using parameters including the locations of the image points (11-13), the building surfaces (#1-#3) viewed at the transmission point, and the range angles ( ⁇ 1- ⁇ 3) of paths available for propagation.
  • the above-noted method provides different speed, accuracy, and complexity required for calculating the propagation path transmitting antenna depending on the selected building surfaces viewed at the location of the transmit antenna.
  • the present invention has been made in an effort to provide a propagation path tracking method having advantages of configuring an accurate propagation model by estimating actual propagation paths.
  • a method for generating a propagation model by tracking a propagation path includes: a) reading 3-dimensional (3D) building information a target area of the propagation model, and establishing a transmission point; b) finding a symmetric point for a building surface searched from the transmission point, and generating a 3D ray tube generated by a reflected electromagnetic wave; c) generating a 3D ray tube generated by an electromagnetic wave diffracted by an edge of the building surface searched from the transmission point; and d) repeating b) and c) for the building surface that is included in or crosses the area of the 3D ray tube of b) and c) and is searched at the symmetric point or the edge of the building surface, and connecting the generated 3D ray tube to the 3D ray tube.
  • a storage medium for recording a program for executing a method in a computer wherein the method includes: a) reading 3-dimensional (3D) building information a target area of the propagation model, and establishing a transmission point; b) finding a symmetric point for a building surface searched from the transmission point, and generating a 3D ray tube generated by a reflected electromagnetic wave; c) generating a 3D ray tube generated by an electromagnetic wave diffracted by an edge of the building surface searched from the transmission point; and d) repeating b) and c) for the building surface that is included in or crosses the area of the 3D ray tube of b) and c) and is searched at the symmetric point or the edge of the building surface, and connecting the generated 3D ray tube to the 3D ray tube.
  • a device for generating a propagation model includes: an information input unit for topography information on a predetermined area and information on electromagnetic waves used for transmitting and receiving signals; a topography generator for generating virtual topography by receiving topography information on the area; an electromagnetic wave tracker for 3D tracking the electromagnetic wave applied from a transmission location, and generating a 3D ray tube; a controller for receiving the 3D ray tube from the electromagnetic wave tracker to calculate a path length of the 3D ray tube, comparing the path length with a threshold length, and controlling the 3D ray tube passing through a receiving location from among the 3D ray tubes; and a propagation model generator for selecting the 3D ray tube passing through the receiving location from among the 3D ray tubes, and calculating the energy intensity of the electromagnetic wave sensed at the receiving location.
  • FIG. 1 shows a conventional method for finding a propagation path using a ray tube.
  • FIG. 2 shows a 3D ray tube formed by an electromagnetic wave reflected on the building surface in a 3D ray tracking method according to an embodiment of the present invention.
  • FIG. 3 shows a 3D ray tube formed by an electromagnetic wave diffracted on the edge of a building in a 3D ray tracking method according to an embodiment of the present invention.
  • FIG. 4 shows a 3D ray tube when the ray tube formed by reflection is reflected on another building surface according to an embodiment of the present invention.
  • FIG. 5 shows a 3D ray tube generated when a 3D ray tube formed by a propagation path caused by reflection is diffracted at the edge of another building surface according to an embodiment of the present invention.
  • FIG. 6 shows a block diagram for a 3D propagation model generator according to an embodiment of the present invention.
  • FIG. 7 shows a method for finding a propagation path configuring a propagation model according to an embodiment of the present invention.
  • FIG. 8 shows a flowchart of a method for generating a propagation model at a receiving point according to an embodiment of the present invention.
  • FIG. 9 shows a 3D ray tube passing through a receiving point in a propagation model generation method according to an embodiment of the present invention.
  • FIG. 2 shows a 3-dimensional (3D) ray tube formed by an electromagnetic wave reflected on the building surface in a 3D ray tracking method according to an embodiment of the present invention.
  • the shape of the building is assumed to be cuboidal, which will be applied to the subsequent embodiment.
  • the 3D ray tube has a pyramid shape.
  • the apex of the pyramid is determined by the location of the transmission point.
  • the location of the transmission point that is generated by surface symmetry with respect to the building surface 100 viewed at the location (A1) of the transmission point is given as an apex (B) of the pyramid.
  • the apex (B) is called an image point in the propagation theory.
  • the half lines connecting the apex (B) and the apexes (C1 , C2, C3, C4) of the building surface 100 are given as edges of the pyramid.
  • the pyramid type ray tube can be defined to correspond to the total set of paths generated when the electromagnetic wave applied from the transmission point (A1) is reflected on the building surface 100.
  • FIG. 3 shows a 3-dimensional (3D) ray tube formed by an electromagnetic wave diffracted on the edge of a building in a 3D ray tracking method according to an embodiment of the present invention.
  • the electromagnetic wave can be diffracted at the edges of the building.
  • the diffraction of electromagnetic waves is an important factor to be considered together with the reflection of electromagnetic waves in the case of estimating the propagation path.
  • the electromagnetic wave provided from the transmission point (A2) meets the edge (a-a 1 ) of the building, the electromagnetic wave is diffracted at the diffraction point (D) at which the electromagnetic wave meets the edge (a-a 1 ).
  • the angle ( ⁇ 1) generated by the location (A2) of the transmission point and the diffraction point (D) is maintained, and the electromagnetic wave is opened at the diffraction point (D) and is radiated in all directions.
  • the electromagnetic wave diffracted at the diffraction point D is passed through the building surface near the edge (a-a 1 ) and is not penetrated into the building, the electromagnetic wave is diffracted at the diffraction point (D) to the building surfaces 200 and 250 as boundaries.
  • a 3D ray tube configured with two building surfaces 200 and 250 near the edge (a-a 1 ) and the diffracted electromagnetic waves radiated with the angle ( ⁇ 1) is generated.
  • the shape of the 3D ray tube is variable depending on at which diffraction point on the edge (a-a 1 ) the electromagnetic wave is diffracted.
  • the drawing on the right of FIG. 3 is a top plan view of the 3D ray tube.
  • the apex (B) of the ray tube formed by reflection shown in FIG. 2 and FIG. 3 and the apex D of the ray tube generated by diffraction can be start points for generating the next ray tube. That is, the 3D ray tube reflected or diffracted again from the symmetric points of the apexes (B, D) with respect to the building surfaces included in the ray tube of the pyramid type including the apexes (B, D) can be generated.
  • FIG. 4 shows a 3-dimensional (3D) ray tube when the ray tube formed by reflection is reflected on another building surface again according to an embodiment of the present invention.
  • the symmetric point for the building surface 300 viewed at the transmission point (A3) is the apex (E 1) of the 3D ray tube.
  • An electromagnetic wave is applied from the transmission point (A3), and the electromagnetic wave reflected on the building surface 300 forms a first 3D ray tube.
  • the electromagnetic wave is radiated again on the building surface 350 included in the first 3D ray tube. It is assumed in the embodiment of the present invention that the whole area of the building surface 350 is included in the first 3D ray tube.
  • the point (E2) symmetric with the apex (E1) with respect to the building surface 300 is the apex of the 3D ray tube. In this instance, the apex (E1) functions as a transmission point.
  • the apex (E 1) is the original source for applying the electromagnetic wave
  • the symmetric point (E2) is the apex (E2) of the new 3D ray tube generated when the reflected electromagnetic wave is reflected again
  • a second 3D ray tube is generated.
  • the 3D ray tube is generated to find all the available propagation path by repeating the above-noted process, the same results as those of the case in which the real electromagnetic wave is applied and the propagation path is measured are acquired.
  • the energy is attenuated when the electromagnetic wave is progressed to the 3D ray tube, it is possible to define predetermined energy intensity, find a path length of the electromagnetic wave having intensity less than that of the energy, and set the path length as a threshold value. When the path length exceeds the threshold value, the 3D ray tube is not progressed.
  • FIG. 5 shows a 3D ray tube generated when a 3D ray tube formed by a propagation path caused by reflection is diffracted at the edge of another building surface according to an embodiment of the present invention.
  • an electromagnetic wave is applied from the transmission point, and the symmetric point (F1) of the transmission point with respect to the building surface 400 is the apex of the 3D ray tube.
  • the symmetric point (F1) of the transmission point with respect to the building surface 400 is the apex of the 3D ray tube.
  • a diffraction wave having a predetermined angle ( ⁇ ) is generated at the point (p) where the electromagnetic wave meets the edge.
  • the 3D ray tube is generated by the two building surfaces adjacent to the corner.
  • the 3D ray tube generated by the diffraction wave is diffracted or reflected again by another building surface to generate a 3D ray tube.
  • the point symmetric with the diffraction point with respect to the other building surface can be an apex of the ray tube generated by reflection.
  • the 3D propagation model generation method can provide a more accurate propagation model in consideration of the vertical component.
  • a propagation model generator according to an embodiment of the present invention will now be described.
  • FIG. 6 shows a block diagram for a 3D propagation model generator according to an embodiment of the present invention.
  • the propagation model generator includes an information input unit 100, a topography generator 200, an electromagnetic wave tracker 300, a propagation model generator 400, and a controller 500.
  • the information input unit 100 receives topography information including the number of buildings and the locations thereof provided in the area that will be used to generate a propagation model. Since topography information is varied according to the location for receiving the electromagnetic waves in the propagation environments such as a micro cell or a pico cell, new topography information is input according to the transmission position. Also, the information input unit 100 can receive information required for the propagation model such as a frequency bandwidth of electromagnetic waves applied to the target propagation model area and antenna characteristics.
  • the topography generator 200 generates 3D virtual topography based on the topography information input to the information input unit 100.
  • the 3D topography is generated by using information on the locations between buildings, heights and shapes of the buildings, roads, and heights of the propagation model areas.
  • the electromagnetic wave tracker 300 tracks the electromagnetic wave applied from the transmission location in a 3D manner and generates a 3D ray tube formed when the electromagnetic wave is reflected on the building surface or is diffracted on the edge.
  • the electromagnetic wave tracker 300 may include a database for storing the generated 3D ray tube.
  • the electromagnetic wave tracker 300 transmits the 3D ray tube stored in the database to the controller 400 or the propagation model generator 500.
  • the controller 400 receives information and targeted propagation model area from the information input unit 100 and the topography generator 200. Also, the controller 400 receives the 3D ray tube from the electromagnetic wave tracker 300, calculates the path of the 3D ray tube generated by electromagnetic wave tracker 300, and compares the path with the threshold value.
  • the threshold value is a propagation path length by which the propagation energy has a value less than a predetermined value in the case of generating the 3D propagation model.
  • the electromagnetic wave having energy less than a predetermined value is difficult to be sensed by the receiver in the case of generating a 3D propagation model, and the calculation of the 3D propagation model including the electromagnetic wave requires more time.
  • the controller 400 instructs the electromagnetic wave tracker 300 to generate a 3D ray tube on other building surfaces except the current building surface at which the 3D ray tube is generated from among a plurality of building surfaces viewed at the transmission location. Also, the controller 400 establishes the electromagnetic wave's transmission location and receiving location. The controller 400 controls the electromagnetic wave tracker 300 to maintain the 3D ray tube generation operation when the propagation path length is less than the threshold value.
  • the propagation model generator 500 receives the 3D ray tube generated by the electromagnetic wave tracker 300 and predetermined receiving location information and generates a 3D propagation model.
  • the propagation model generator 500 calculates the path length of the selected 3D ray tube, finds propagation attenuation according to the path, and calculates the energy intensity of the electromagnetic wave sensed at the receiving location.
  • the above-noted operation is performed for all the 3D ray tubes, and as a result, the energy intensity of the electromagnetic wave sensed at the receiving location can be found, and the whole 3D propagation model can be generated by repeating the above-noted operation at different locations in the target area.
  • FIG. 7 shows a method for finding a propagation path configuring a propagation model according to an embodiment of the present invention.
  • 3D building information for the area for configuring the propagation model is read (S100).
  • the information can be configured by simplifying the building as a cuboid for ease of description.
  • the building is assumed to be cuboidal in the fourth embodiment of the present invention.
  • a transmission point is established and characteristic values including the location of the transmission point and the antenna for sending electromagnetic waves at the transmission point are input (S200).
  • the building surfaces viewed at the transmission point are searched and a building surface to which the electromagnetic wave will be applied is selected from among the searched building surfaces (S300).
  • the symmetric point for the transmission point with respect to the selected building surface is found and established (S400).
  • the apexes of the building surface are connected to the symmetric point with half lines (S410).
  • a 3D ray tube for generating the reflected electromagnetic wave is then generated, the symmetric point is the apex of the 3D ray tube, and the triangle formed by the symmetric point and the edges of the building surface is a cone type side.
  • the formed 3D ray tube is stored (S420). Since the energy of the electromagnetic wave is attenuated while the electromagnetic wave is progressed to the ray tube, it is possible to establish a predetermined propagation path length as a threshold value and prevent the ray tube generated by electromagnetic waves greater than the threshold value from being generated. Therefore, the propagation path length formed by connecting the 3D ray tubes is compared with the threshold value each time the above-noted operation is repeated (S430).
  • the symmetric point can be a source for generating another 3D ray tube. That is, the symmetric point functions to apply the electromagnetic waves in a like manner of the transmission point. Therefore, the operation for forming a 3D ray tube caused by reflection or diffraction on another building surface that is included in the 3D ray tube area or meets the area of the 3D ray tube and is viewed at the symmetric point is repeated.
  • a 3D ray tube for another building surface searched at the corresponding transmission point is generated.
  • the method for generating the 3D ray tube on another building surface corresponds to the above-described method.
  • the angle between the vertical component of the edge and the line for connecting the electromagnetic wave applying location and a random point for configuring an edge at which diffraction is generated is calculated (S500).
  • the diffraction wave is diffracted at the edge while maintaining the angle with the vertical component of the edge.
  • a 3D ray tube that has building surfaces adjacent to the edges as boundaries and has a set of diffraction waves having a predetermined angle with the vertical component is generated.
  • the entire 3D ray tube by diffraction can be generated for all the points configuring the edge (S510).
  • the generated 3D ray tube is stored (S520).
  • the subsequent 3D ray tube can be set as not generated. Therefore, each time the above-noted operation is repeated, the threshold value and the propagation path length of the connected 3D ray tubes are compared (S530). In a like manner of the symmetric point, the edge of the building surface at which diffraction is generated can be a source for generating another 3D ray tube.
  • the operation for generating the 3D ray tube caused by reflection or the 3D ray tube caused by the diffraction wave at the edge is performed for the building surface that is included by the 3D ray tube generated at the diffracted edge or that meets the 3D ray tube area and is viewed at the diffraction point is repeated.
  • a 3D ray tube for another building surface searched at the corresponding transmission point is generated.
  • the method for generating a 3D ray tube for other building surfaces may correspond to the above-described method.
  • the 3D ray tubes when the 3D ray tubes are generated, stored, and connected, more accurate results are acquired since the vertical component on the ground is considered in the case of expecting the path of electromagnetic waves applied by the transmit antenna.
  • the 3D ray tube generated by the reflected electromagnetic wave can generate a 3D ray tube on another building surface by diffraction.
  • the 3D ray tube generated by diffraction can generate a 3D ray tube on another building surface by reflection. Accordingly, the path of electromagnetic waves applied at the transmission point can be estimated in a lime manner of the actual cases by combining the 3D ray tube caused by a plurality times of reflection and the 3D ray tube by diffraction.
  • FIG. 8 shows a flowchart of a method for generating a propagation model at a receiving point according to an embodiment of the present invention.
  • FIG. 9 shows a 3D ray tube passing through a receiving point in a propagation model generation method according to an embodiment of the present invention.
  • a receiving point is established in the cell for generating a propagation model (S600).
  • a 3D ray tube passing through the receiving point is detected from among a plurality of the generated 3D ray tubes (S610).
  • the 3D ray tube passing through the receiving point can be found by using the method shown in FIG. 8.
  • the 3D ray tube characterized by the location vector of the symmetric point, the normal vector of the building surface, and the normal vector of the surface of the 3D ray tube satisfying the conditions of Math Figure 1 and Math Figure 2 is found.
  • Propagation attenuation can be calculated by using the propagation path length R and the reflection coefficient of the building surface (S630).
  • the propagation attenuation values for all the 3D ray tubes passing through the receiving point can be calculated. It is determined whether the propagation attenuation calculation for the detected 3D ray tubes has been performed (S640). The above-noted process is repeated when there is a 3D ray tube for calculating the propagation attenuation. The propagation attenuation calculation is terminated in another case.
  • the intensity of received electromagnetic waves can be estimated with the sum of all the electromagnetic waves reaching the receiving point (S650).
  • the propagation model can be completed when the above-noted operation is repeated by changing the location of the receiving point in the target area for the propagation model.
  • the propagation attenuation found for all 3D ray tubes passing through the receiving point is very similar to the results acquired by measuring the real propagation path. Also, it is obvious to a person skilled in the art that the propagation attenuation for the 3D ray tube by diffraction can be generated by finding a 3D ray tube passing through the receiving point.
  • the above-described embodiment of the present invention can also be realized through a program for realizing the functions corresponding to the configuration of the embodiment of the present invention or a recording medium for recording the program, which can be realized by a skilled person in the art.
  • Differences between the embodiment and the real test results acquired by measuring propagation attenuation at the location for receiving electromagnetic waves can be substantially reduced. Therefore, a more accurate propagation model for the location of receiving the electromagnetic waves can be generated.

Abstract

The present invention relates to a method for tracking a propagation path and generating a propagation model. 3D building information on the target area of the propagation model is read and a transmission point is established. A symmetric point for the building surface searched from the transmission point is found, and a 3D ray tube generated by reflected electromagnetic waves is generated. A 3D ray tube generated by the electromagnetic waves diffracted by the edge of the building surface searched by the transmission point is generated. The process for generating a 3D ray tube by reflection or diffraction for the building surface that is included in or crosses the area of the 3D ray tube generated by reflection or diffraction and is searched at the symmetric point or on the edge of the building surface is repeated, and the generated 3D ray tube is connected to the 3D ray tube. Therefore, the accurate propagation model is generated at the location for receiving the real electromagnetic waves.

Description

[DESCRIPTION]
[Invention Title]
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
[Technical Field]
The present invention relates to a propagation model generating method, and in particular, it relates to a method for analyzing a propagation path by using a 3-dimensional ray tracking method, and generating a corresponding propagation model.
[Background Art]
Interests on the urban electromagnetic wave environments have been increased as demands on the personal communication services have been increased. The urban electromagnetic wave environment represents a small cell having a service radius within 1 km. The small cell includes a micro cell and a pico cell, and the received power of the cells greatly depends on the electromagnetic wave environment between the base station and the mobile station differing from the macro cell having a relatively big service radius. Therefore, in order to estimate the accurate received power, a precise analysis is required, and a propagation model generated based on the corresponding propagation path is further needed.
The conventional method for generating the propagation model includes a statistical method for generating a propagation model by acquiring statistics based on the test result and a computer estimation method for generating a propagation model by estimating a computerized propagation path based on theoretic schemes. The method for generating a propagation model through statistics has an advantage in easily acquiring estimates, but has a problem of acquiring the accurate propagation model since it considers no real topography and building arrangement. The computerized estimation method has an advantage in acquiring a very accurate propagation model by computing available propagation paths by using the real building data. However, the computerized estimation method has a problem of estimating all the available propagation paths and a drawback of spending much time in estimating all the propagation paths.
The computerized estimation method is classified as two methods depending on the propagation path tracking method. The first method is to generate half infinite lines in all directions at the location of a transmit antenna and check the point where the straight line meets the building surface. The reason for using the straight lines is, though not the same as the phenomenon of the actual propagation phenomenon, that the area influenced by diffraction is relatively narrow and can be neglected when the area of the building surface is very greater than the wavelength of the corresponding electromagnetic wave. A straight line corresponding to the reflected wave can be generated according to the angle between the building surface and the straight line when the building surface and the electromagnetic wave radiated from the transmit antenna meet, and it is determined whether the above-noted straight line meets the building surface again and the straight line is passed through the point that corresponds to the measurement point of the propagation model. When the path of the electromagnetic wave has a measurement point, estimation results are found by calculating the attenuation caused by the distance from the transmission point to the measurement point and the attenuation caused by the reflection on the wall surface. The calculation of the actual propagation model through the above-described methods generates different accuracy depending on the number of infinite straight lines. The more infinite straight lines are used, the more accuracy of the propagation model is improve, but much time required for calculating the propagation model is used. The second method has improved the problem, which forms a ray tube generated by a reflected straight line by radiating one straight line on the building surface viewed at the transmit antenna. The ray tube represents a pack of a plurality of rays, and all the rays in the same ray tube have the same propagation path value.
FIG. 1 shows a conventional method for finding a propagation path by using a ray tube. A plurality of electromagnetic waves is applied at regular intervals from a transmission point, each of the electromagnetic waves is tracked, and a set of paths formed by a plurality of electromagnetic waves configures the ray tube. Among the ray tubes, a ray tube reaching the receiving point is found. All the paths of the formed ray tube have the same propagation path value. First, the location for the electromagnetic wave transmit antenna is given as a transmission point, and the building surface viewed at the transmission point is found. An image point (11) at which the transmission point is symmetric with respect to the building surface (#1) is found, and an image point (I2) symmetric with respect to the building surface (#2) is found from the image point (11). An image point (I3) is found in a like manner. A path on which the electromagnetic wave provided from the transmission point is reflected is found by finding the location of the image point (11-13). In this instance, range angles (Φ 1-Φ 3) of path available for propagation are considered. The ray tube caused by the reflected electromagnetic wave is formed by using parameters including the locations of the image points (11-13), the building surfaces (#1-#3) viewed at the transmission point, and the range angles (Φ 1-Φ3) of paths available for propagation. The above-noted method provides different speed, accuracy, and complexity required for calculating the propagation path transmitting antenna depending on the selected building surfaces viewed at the location of the transmit antenna. However, in order to find the building surface viewed at the transmission point in the above-noted method, 2-dimensional information corresponding to the apex of the horizontal surface is used from among information on the surface and the edge of the building. Therefore, the progress of the electromagnetic wave in the vertical direction on the ground is not considered. An error is generated between the ray tube which is a set of propagation paths reaching the receiving point (R) and the ray tube at the receiving point (R) according to the propagation path estimated by using a computer.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
[Disclosure]
[Technical Problem]
The present invention has been made in an effort to provide a propagation path tracking method having advantages of configuring an accurate propagation model by estimating actual propagation paths.
[Technical Solution]
In one aspect of the present invention, a method for generating a propagation model by tracking a propagation path includes: a) reading 3-dimensional (3D) building information a target area of the propagation model, and establishing a transmission point; b) finding a symmetric point for a building surface searched from the transmission point, and generating a 3D ray tube generated by a reflected electromagnetic wave; c) generating a 3D ray tube generated by an electromagnetic wave diffracted by an edge of the building surface searched from the transmission point; and d) repeating b) and c) for the building surface that is included in or crosses the area of the 3D ray tube of b) and c) and is searched at the symmetric point or the edge of the building surface, and connecting the generated 3D ray tube to the 3D ray tube.
In another aspect of the present invention, provided is a storage medium for recording a program for executing a method in a computer wherein the method includes: a) reading 3-dimensional (3D) building information a target area of the propagation model, and establishing a transmission point; b) finding a symmetric point for a building surface searched from the transmission point, and generating a 3D ray tube generated by a reflected electromagnetic wave; c) generating a 3D ray tube generated by an electromagnetic wave diffracted by an edge of the building surface searched from the transmission point; and d) repeating b) and c) for the building surface that is included in or crosses the area of the 3D ray tube of b) and c) and is searched at the symmetric point or the edge of the building surface, and connecting the generated 3D ray tube to the 3D ray tube. In another aspect of the present invention, a device for generating a propagation model includes: an information input unit for topography information on a predetermined area and information on electromagnetic waves used for transmitting and receiving signals; a topography generator for generating virtual topography by receiving topography information on the area; an electromagnetic wave tracker for 3D tracking the electromagnetic wave applied from a transmission location, and generating a 3D ray tube; a controller for receiving the 3D ray tube from the electromagnetic wave tracker to calculate a path length of the 3D ray tube, comparing the path length with a threshold length, and controlling the 3D ray tube passing through a receiving location from among the 3D ray tubes; and a propagation model generator for selecting the 3D ray tube passing through the receiving location from among the 3D ray tubes, and calculating the energy intensity of the electromagnetic wave sensed at the receiving location.
[Description of Drawings]
FIG. 1 shows a conventional method for finding a propagation path using a ray tube.
FIG. 2 shows a 3D ray tube formed by an electromagnetic wave reflected on the building surface in a 3D ray tracking method according to an embodiment of the present invention.
FIG. 3 shows a 3D ray tube formed by an electromagnetic wave diffracted on the edge of a building in a 3D ray tracking method according to an embodiment of the present invention.
FIG. 4 shows a 3D ray tube when the ray tube formed by reflection is reflected on another building surface according to an embodiment of the present invention. FIG. 5 shows a 3D ray tube generated when a 3D ray tube formed by a propagation path caused by reflection is diffracted at the edge of another building surface according to an embodiment of the present invention.
FIG. 6 shows a block diagram for a 3D propagation model generator according to an embodiment of the present invention.
FIG. 7 shows a method for finding a propagation path configuring a propagation model according to an embodiment of the present invention.
FIG. 8 shows a flowchart of a method for generating a propagation model at a receiving point according to an embodiment of the present invention.
FIG. 9 shows a 3D ray tube passing through a receiving point in a propagation model generation method according to an embodiment of the present invention.
[BEST MODE] An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. 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. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
A method for generating a propagation model by tracking a propagation path according to an embodiment of the present invention will now be described in detail with reference to drawings.
FIG. 2 shows a 3-dimensional (3D) ray tube formed by an electromagnetic wave reflected on the building surface in a 3D ray tracking method according to an embodiment of the present invention. In this instance, the shape of the building is assumed to be cuboidal, which will be applied to the subsequent embodiment.
As shown in FIG. 2, the 3D ray tube has a pyramid shape. The apex of the pyramid is determined by the location of the transmission point. The location of the transmission point that is generated by surface symmetry with respect to the building surface 100 viewed at the location (A1) of the transmission point is given as an apex (B) of the pyramid. The apex (B) is called an image point in the propagation theory. The half lines connecting the apex (B) and the apexes (C1 , C2, C3, C4) of the building surface 100 are given as edges of the pyramid. The pyramid type ray tube can be defined to correspond to the total set of paths generated when the electromagnetic wave applied from the transmission point (A1) is reflected on the building surface 100. FIG. 3 shows a 3-dimensional (3D) ray tube formed by an electromagnetic wave diffracted on the edge of a building in a 3D ray tracking method according to an embodiment of the present invention.
As shown in FIG. 3, the electromagnetic wave can be diffracted at the edges of the building. The diffraction of electromagnetic waves is an important factor to be considered together with the reflection of electromagnetic waves in the case of estimating the propagation path.
When the electromagnetic wave provided from the transmission point (A2) meets the edge (a-a1) of the building, the electromagnetic wave is diffracted at the diffraction point (D) at which the electromagnetic wave meets the edge (a-a1). The angle (θ 1) generated by the location (A2) of the transmission point and the diffraction point (D) is maintained, and the electromagnetic wave is opened at the diffraction point (D) and is radiated in all directions. When it is assumed that the electromagnetic wave diffracted at the diffraction point D is passed through the building surface near the edge (a-a1) and is not penetrated into the building, the electromagnetic wave is diffracted at the diffraction point (D) to the building surfaces 200 and 250 as boundaries. Therefore, a 3D ray tube configured with two building surfaces 200 and 250 near the edge (a-a1) and the diffracted electromagnetic waves radiated with the angle (θ 1) is generated. The shape of the 3D ray tube is variable depending on at which diffraction point on the edge (a-a1) the electromagnetic wave is diffracted. The drawing on the right of FIG. 3 is a top plan view of the 3D ray tube.
In the 3D ray tracking method according to the embodiment of the present invention, the apex (B) of the ray tube formed by reflection shown in FIG. 2 and FIG. 3 and the apex D of the ray tube generated by diffraction can be start points for generating the next ray tube. That is, the 3D ray tube reflected or diffracted again from the symmetric points of the apexes (B, D) with respect to the building surfaces included in the ray tube of the pyramid type including the apexes (B, D) can be generated. FIG. 4 shows a 3-dimensional (3D) ray tube when the ray tube formed by reflection is reflected on another building surface again according to an embodiment of the present invention.
As shown in FIG. 4, the symmetric point for the building surface 300 viewed at the transmission point (A3) is the apex (E 1) of the 3D ray tube. An electromagnetic wave is applied from the transmission point (A3), and the electromagnetic wave reflected on the building surface 300 forms a first 3D ray tube. The electromagnetic wave is radiated again on the building surface 350 included in the first 3D ray tube. It is assumed in the embodiment of the present invention that the whole area of the building surface 350 is included in the first 3D ray tube. The point (E2) symmetric with the apex (E1) with respect to the building surface 300 is the apex of the 3D ray tube. In this instance, the apex (E1) functions as a transmission point. That is, the apex (E 1) is the original source for applying the electromagnetic wave, the symmetric point (E2) is the apex (E2) of the new 3D ray tube generated when the reflected electromagnetic wave is reflected again, and a second 3D ray tube is generated. When the 3D ray tube is generated to find all the available propagation path by repeating the above-noted process, the same results as those of the case in which the real electromagnetic wave is applied and the propagation path is measured are acquired. Also, since the energy is attenuated when the electromagnetic wave is progressed to the 3D ray tube, it is possible to define predetermined energy intensity, find a path length of the electromagnetic wave having intensity less than that of the energy, and set the path length as a threshold value. When the path length exceeds the threshold value, the 3D ray tube is not progressed.
FIG. 5 shows a 3D ray tube generated when a 3D ray tube formed by a propagation path caused by reflection is diffracted at the edge of another building surface according to an embodiment of the present invention. As shown in FIG. 5, an electromagnetic wave is applied from the transmission point, and the symmetric point (F1) of the transmission point with respect to the building surface 400 is the apex of the 3D ray tube. When one of the reflected electromagnetic waves configuring the 3D ray tube is passed through the edge (b-b1) of the building surface 450, a diffraction wave having a predetermined angle ( ω ) is generated at the point (p) where the electromagnetic wave meets the edge. As shown in FIG. 3, the 3D ray tube is generated by the two building surfaces adjacent to the corner. The 3D ray tube generated by the diffraction wave is diffracted or reflected again by another building surface to generate a 3D ray tube. When the 3D ray tube is reflected again, the point symmetric with the diffraction point with respect to the other building surface can be an apex of the ray tube generated by reflection.
Accordingly, the 3D propagation model generation method according to the embodiment of the present invention can provide a more accurate propagation model in consideration of the vertical component.
A propagation model generator according to an embodiment of the present invention will now be described.
FIG. 6 shows a block diagram for a 3D propagation model generator according to an embodiment of the present invention. As shown in FIG. 6, the propagation model generator includes an information input unit 100, a topography generator 200, an electromagnetic wave tracker 300, a propagation model generator 400, and a controller 500.
The information input unit 100 receives topography information including the number of buildings and the locations thereof provided in the area that will be used to generate a propagation model. Since topography information is varied according to the location for receiving the electromagnetic waves in the propagation environments such as a micro cell or a pico cell, new topography information is input according to the transmission position. Also, the information input unit 100 can receive information required for the propagation model such as a frequency bandwidth of electromagnetic waves applied to the target propagation model area and antenna characteristics.
The topography generator 200 generates 3D virtual topography based on the topography information input to the information input unit 100.
The 3D topography is generated by using information on the locations between buildings, heights and shapes of the buildings, roads, and heights of the propagation model areas.
When the transmission location is established, the electromagnetic wave tracker 300 tracks the electromagnetic wave applied from the transmission location in a 3D manner and generates a 3D ray tube formed when the electromagnetic wave is reflected on the building surface or is diffracted on the edge. The electromagnetic wave tracker 300 may include a database for storing the generated 3D ray tube. The electromagnetic wave tracker 300 transmits the 3D ray tube stored in the database to the controller 400 or the propagation model generator 500.
The controller 400 receives information and targeted propagation model area from the information input unit 100 and the topography generator 200. Also, the controller 400 receives the 3D ray tube from the electromagnetic wave tracker 300, calculates the path of the 3D ray tube generated by electromagnetic wave tracker 300, and compares the path with the threshold value. The threshold value is a propagation path length by which the propagation energy has a value less than a predetermined value in the case of generating the 3D propagation model. The electromagnetic wave having energy less than a predetermined value is difficult to be sensed by the receiver in the case of generating a 3D propagation model, and the calculation of the 3D propagation model including the electromagnetic wave requires more time. Therefore, when the propagation path length is greater than the threshold value, the controller 400 instructs the electromagnetic wave tracker 300 to generate a 3D ray tube on other building surfaces except the current building surface at which the 3D ray tube is generated from among a plurality of building surfaces viewed at the transmission location. Also, the controller 400 establishes the electromagnetic wave's transmission location and receiving location. The controller 400 controls the electromagnetic wave tracker 300 to maintain the 3D ray tube generation operation when the propagation path length is less than the threshold value.
The propagation model generator 500 receives the 3D ray tube generated by the electromagnetic wave tracker 300 and predetermined receiving location information and generates a 3D propagation model. The propagation model generator 500 calculates the path length of the selected 3D ray tube, finds propagation attenuation according to the path, and calculates the energy intensity of the electromagnetic wave sensed at the receiving location. The above-noted operation is performed for all the 3D ray tubes, and as a result, the energy intensity of the electromagnetic wave sensed at the receiving location can be found, and the whole 3D propagation model can be generated by repeating the above-noted operation at different locations in the target area.
FIG. 7 shows a method for finding a propagation path configuring a propagation model according to an embodiment of the present invention.
As shown in FIG. 7, 3D building information for the area for configuring the propagation model is read (S100). The information can be configured by simplifying the building as a cuboid for ease of description. The building is assumed to be cuboidal in the fourth embodiment of the present invention. In order to calculate the propagation model, a transmission point is established and characteristic values including the location of the transmission point and the antenna for sending electromagnetic waves at the transmission point are input (S200). The building surfaces viewed at the transmission point are searched and a building surface to which the electromagnetic wave will be applied is selected from among the searched building surfaces (S300). The symmetric point for the transmission point with respect to the selected building surface is found and established (S400). The apexes of the building surface are connected to the symmetric point with half lines (S410). A 3D ray tube for generating the reflected electromagnetic wave is then generated, the symmetric point is the apex of the 3D ray tube, and the triangle formed by the symmetric point and the edges of the building surface is a cone type side. The formed 3D ray tube is stored (S420). Since the energy of the electromagnetic wave is attenuated while the electromagnetic wave is progressed to the ray tube, it is possible to establish a predetermined propagation path length as a threshold value and prevent the ray tube generated by electromagnetic waves greater than the threshold value from being generated. Therefore, the propagation path length formed by connecting the 3D ray tubes is compared with the threshold value each time the above-noted operation is repeated (S430). When the propagation path length is less than the threshold value, the symmetric point can be a source for generating another 3D ray tube. That is, the symmetric point functions to apply the electromagnetic waves in a like manner of the transmission point. Therefore, the operation for forming a 3D ray tube caused by reflection or diffraction on another building surface that is included in the 3D ray tube area or meets the area of the 3D ray tube and is viewed at the symmetric point is repeated. When the propagation path length is less than the threshold value, a 3D ray tube for another building surface searched at the corresponding transmission point is generated. The method for generating the 3D ray tube on another building surface corresponds to the above-described method.
When the electromagnetic wave applied from the initial transmission point is diffracted one the edge of the building, the angle between the vertical component of the edge and the line for connecting the electromagnetic wave applying location and a random point for configuring an edge at which diffraction is generated is calculated (S500). The diffraction wave is diffracted at the edge while maintaining the angle with the vertical component of the edge. A 3D ray tube that has building surfaces adjacent to the edges as boundaries and has a set of diffraction waves having a predetermined angle with the vertical component is generated. In a like manner, the entire 3D ray tube by diffraction can be generated for all the points configuring the edge (S510). The generated 3D ray tube is stored (S520). In the case of the 3D ray tube by diffraction, since the electromagnetic wave is progressed to the ray tube and the energy is attenuated, when a predetermined propagation path length is set to be a threshold value and the propagation path length acquired by connecting the stored 3 ray tubes is greater than the threshold value, the subsequent 3D ray tube can be set as not generated. Therefore, each time the above-noted operation is repeated, the threshold value and the propagation path length of the connected 3D ray tubes are compared (S530). In a like manner of the symmetric point, the edge of the building surface at which diffraction is generated can be a source for generating another 3D ray tube. Therefore, when the propagation path length is less than the threshold value, the operation for generating the 3D ray tube caused by reflection or the 3D ray tube caused by the diffraction wave at the edge is performed for the building surface that is included by the 3D ray tube generated at the diffracted edge or that meets the 3D ray tube area and is viewed at the diffraction point is repeated. When the propagation path length is greater than the threshold value, a 3D ray tube for another building surface searched at the corresponding transmission point is generated. The method for generating a 3D ray tube for other building surfaces may correspond to the above-described method.
Accordingly, when the 3D ray tubes are generated, stored, and connected, more accurate results are acquired since the vertical component on the ground is considered in the case of expecting the path of electromagnetic waves applied by the transmit antenna. The 3D ray tube generated by the reflected electromagnetic wave can generate a 3D ray tube on another building surface by diffraction. In addition, the 3D ray tube generated by diffraction can generate a 3D ray tube on another building surface by reflection. Accordingly, the path of electromagnetic waves applied at the transmission point can be estimated in a lime manner of the actual cases by combining the 3D ray tube caused by a plurality times of reflection and the 3D ray tube by diffraction.
Referring to FIG. 8 and FIG. 9, a method for generating a propagation model will now be described.
FIG. 8 shows a flowchart of a method for generating a propagation model at a receiving point according to an embodiment of the present invention. FIG. 9 shows a 3D ray tube passing through a receiving point in a propagation model generation method according to an embodiment of the present invention.
As shown in FIG. 8, a receiving point is established in the cell for generating a propagation model (S600). A 3D ray tube passing through the receiving point is detected from among a plurality of the generated 3D ray tubes (S610). In this instance, the 3D ray tube passing through the receiving point can be found by using the method shown in FIG. 8. The same the 3D ray tube can be found by using a location vector ( r ) of the receiving point, a location vector ( 7"-*") of the symmetric point, a normal vector ( ^ ) of the building surface, and normal vectors ( *■** ,i=1 ,2,3,4) of surfaces configuring the 3D ray tube boundaries. The 3D ray tube characterized by the location vector of the symmetric point, the normal vector of the building surface, and the normal vector of the surface of the 3D ray tube satisfying the conditions of Math Figure 1 and Math Figure 2 is found.
(Math Figure 1)
Figure imgf000018_0001
(Math Figure 2)
ή, *(r - TX' ) < Q (/ = 1,2,3,4)
When the 3D ray tube passing through the receiving point is found by using Math Figure 1 and Math Figure 2, the propagation path from the transmission point to the receiving point is calculated in the 3D ray tube
(S620). When it is assumed that the 3D coordinate of the receiving point is given (xr, yr, zr) and the 3D coordinate of the symmetric point is given as
(xs, ys, zs), the propagation path length R can be found from Math Figure 3.
(Math Figure 3)
R = VOr -χ,y +Ov -y.y +<Λ - 2J
Propagation attenuation can be calculated by using the propagation path length R and the reflection coefficient of the building surface (S630). The propagation attenuation values for all the 3D ray tubes passing through the receiving point can be calculated. It is determined whether the propagation attenuation calculation for the detected 3D ray tubes has been performed (S640). The above-noted process is repeated when there is a 3D ray tube for calculating the propagation attenuation. The propagation attenuation calculation is terminated in another case. When the propagation attenuation calculation is finished, the intensity of received electromagnetic waves can be estimated with the sum of all the electromagnetic waves reaching the receiving point (S650). The propagation model can be completed when the above-noted operation is repeated by changing the location of the receiving point in the target area for the propagation model.
Accordingly, the propagation attenuation found for all 3D ray tubes passing through the receiving point is very similar to the results acquired by measuring the real propagation path. Also, it is obvious to a person skilled in the art that the propagation attenuation for the 3D ray tube by diffraction can be generated by finding a 3D ray tube passing through the receiving point. The above-described embodiment of the present invention can also be realized through a program for realizing the functions corresponding to the configuration of the embodiment of the present invention or a recording medium for recording the program, which can be realized by a skilled person in the art. While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
[Industrial Applicability]
Differences between the embodiment and the real test results acquired by measuring propagation attenuation at the location for receiving electromagnetic waves can be substantially reduced. Therefore, a more accurate propagation model for the location of receiving the electromagnetic waves can be generated.

Claims

[CLAIMS]
1. A method for generating a propagation model by tracking a propagation path, comprising: a) reading 3-dimensional (3D) building information a target area of the propagation model, and establishing a transmission point; b) finding a symmetric point for a building surface searched from the transmission point, and generating a 3D ray tube generated by a reflected electromagnetic wave; c) generating a 3D ray tube generated by an electromagnetic wave diffracted by an edge of the building surface searched from the transmission point; and d) repeating b) and c) for the building surface that is included in or crosses the area of the 3D ray tube of b) and c) and is searched at the symmetric point or the edge of the building surface, and connecting the generated 3D ray tube to the 3D ray tube.
2. The method of claim 1 , wherein d) is repeated for a predetermined number of times, the number of times is established to be a number of times that is repeated when the total path length generated by reflection or diffraction of the electromagnetic wave is compared with a threshold value and the path length is found to be less than the threshold value.
3. The method of claim 2, wherein the threshold value is established according to the path length having energy less than a predetermined value by considering the feature that the energy of the electromagnetic wave is reduced as the electromagnetic wave is repeatedly reflected or diffracted.
4. The method of claim 1 , wherein a) comprises: connecting the symmetric point and the apexes of the building surface by using half lines; and generating the 3D ray tube including a plurality of side surfaces including the half line as an edge and a triangle configured by the symmetric point and the edge of the building surface.
5. The method of claim 1 , wherein b) comprises: i) calculating the angle between the line for connecting the transmission point and a random diffraction point on the edge of the building surface and the line that is passed through the transmission point and is parallel with the ground; ii) generating a diffracted 3D ray tube having the angle at the diffraction point and a set of a plurality of half lines provided between the building surfaces adjacent to the edge; and iii) generating the 3D ray tube having a set of the diffracted 3D ray tubes formed at the diffraction point by repeating i) and ii) for another diffraction on the edge.
6. The method of claim 1 , wherein d) further comprises storing the connected 3D ray tubes.
7. The method of claim 6, further comprising establishing a receiving point in the target area of the propagation model, and finding a 3D ray tube passing through the receiving point from among the stored 3D ray tubes.
8. The method of claim 7, further comprising calculating propagation attenuation by using the 3D ray tube passing through the receiving point, and estimating the intensity of the received electromagnetic wave at the receiving point.
9. The method of claim 8, wherein it is repeated to establish another receiving point in the propagation model generated area to find a 3D ray tube passing through the receiving point from among the stored 3D ray tubes, and calculate propagation attenuation by using the 3D ray tube to estimate the intensity of the receiving electromagnetic wave at the receiving point.
10. A storage medium for recording a program for executing the method disclosed in any one of claim 1 to claim 9 in a computer.
11. A device for generating a propagation model comprising: an information input unit for topography information on a predetermined area and information on electromagnetic waves used for transmitting and receiving signals; a topography generator for generating virtual topography by receiving topography information on the area; an electromagnetic wave tracker for 3D tracking the electromagnetic wave applied from a transmission location, and generating a 3D ray tube; a controller for receiving the 3D ray tube from the electromagnetic wave tracker to calculate a path length of the 3D ray tube, comparing the path length with a threshold length, and controlling the 3D ray tube passing through a receiving location from among the 3D ray tubes; and a propagation model generator for selecting the 3D ray tube passing through the receiving location from among the 3D ray tubes, and calculating the energy intensity of the electromagnetic wave sensed at the receiving location.
12. The device of claim 11 , wherein the electromagnetic wave tracker includes a database for storing the generated 3D ray tube.
13. The device of claim 11 , wherein in the controller, the threshold length is a propagation path length for the energy of the electromagnetic wave having a value less than a predetermined value.
14. The device of claim 11 , wherein the controller terminates generation on the 3D ray tube and generates a 3D ray tube for another building surface viewed at the transmission location when the path length of the 3D ray tube reaches the threshold length.
15. The device of claim 11 , wherein the propagation model generator finds energy attenuation of the 3D ray tube including the receiving location and generates the 3D propagation model with the total sum of energy of the 3D ray tube.
16. The device of claim 11 , wherein the electromagnetic wave tracker tracks the propagation path by reflection or diffraction of electromagnetic waves for the building surface sensed from the transmission point in the target area of the 3D propagation model, and generates a 3D ray tube formed by the electromagnetic wave.
PCT/KR2006/003767 2005-09-23 2006-09-22 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 WO2007035052A1 (en)

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