JP2006087038A - Device and method for estimating radio-wave propagation path - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate a propagation path at a high speed on the real conditions in consideration of the complication of a building surface and an obstruction on a road without increasing the complication of a local-produce data, and to arithmetically operate a receiving-signal data. <P>SOLUTION: A boundary detecting section 104 searches a polygon (the obstruction) existing on the straight line of rays emitted by a ray radiation section 103 and a receiver. A uniform random-number generating section 105 generates a uniform random number. A random-number distribution selecting section 106 selects a random-number distribution from the attribute information of the obstruction. A random-number distribution weight section 107 weights the uniform random number according to the random-number distribution selected by the random-number distribution selecting section 106. A boundary-attenuation arithmetic section 108 obtains an angle on a space among the rays and an obstruction surface on the basis of the inclination of the obstruction surface and the attribute of the obstruction. The arithmetic section 108 arithmetically operates the quantity of an attenuation by a reflection, a transmission and a diffraction and arithmetically operates the quantity of the vector azimuth of the rays changed. The boundary-attenuation arithmetic section 108 determines whether or not the arithmetic operation is conducted by the random number output from the random-number distribution weight section 107 in this case. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio wave propagation path estimation apparatus and a radio wave propagation path estimation method using a ray tracing method for estimating a propagation path between a radio wave transmission source and a receiving apparatus using feature data.

  Currently, propagation prediction using a statistical formula that is a function of the distance between transmission and reception is generally used. Statistical formulas are highly accurate by subdividing cases such as urban areas and suburbs. The Okumura-Kashiwa curve corresponds to this.

  There is a so-called quasi-empirical formula as an extension of this. This is an estimation that takes into account more specific parameters such as the positional relationship of transmitting and receiving stations and the height of surrounding buildings in addition to statistical fluctuations. This method is classified.

  However, those obtained by these estimation formulas cannot perform delay profile estimation (path estimation) and radio wave arrival angle estimation only with the received electric field strength. A method of estimating estimation parameters such as received electric field strength and delay profile, angle of arrival, and angle of departure based on feature data such as buildings and the ground. Is the ray-trace method.

  When a radio wave transmitted from a certain transmitter is received by a certain receiver, the radio wave passes through several paths, and a certain wave directly reaches the receiver through reflection, transmission and diffraction by an obstacle. This single path is called a propagation channel. When there are a plurality of propagation channels, the radio waves are canceled or added to each other depending on their phase components. Also, the delay time and phase can be calculated from the speed of light and wavelength based on the path length of the arrived radio wave.

  In order to search for this path, a method in which rays (rays) are discretely emitted from the transmitter at Δθ and the receiver is traced while repeating reflection, transmission, and diffraction by an obstacle is called a launching method. (FIG. 13). In the launching method, radio waves are repeatedly attenuated and changed in polarization state at reflection points, transmission points, and diffraction points.

  As another method of ray tracing, a method of searching a path by creating a virtual image of a transmitter for all obstacles is called an imaging method. This method can be used as a model for evaluating a relatively narrow area such as a room because the number of combinations of paths to be searched exponentially increases as the number of obstacles increases, while an accurate search is possible.

  The ray-tracing method has a huge amount of computation, but has been put into practical use due to recent advances in computer power and ingenuity in route search methods. Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of calculating a field intensity by performing path estimation at high speed without sacrificing estimation accuracy. When the base station antenna height is lower than the surrounding buildings in an urban area, it is known that the main route of radio waves is along the road. Patent Document 1 discloses a method for limiting the number of target obstacles by limiting building data existing along a route on a road estimated in advance as an obstacle.

On the other hand, a method of processing received signal data by statistical processing using Rayleigh distribution rules in an absolute estimated path by the ray tracing method is disclosed (for example, see Patent Document 2). The reception level of the multipath synthesized wave greatly fluctuates (fading) locally depending on each phase component. When this variation is estimated by the ray tracing method, it is generally necessary to search for a path for each point of about a half wavelength of the carrier frequency. In this case, for example, it becomes 3 cm at 5 GHz, and if it is attempted to estimate in a wide area, it is impossible to finish the calculation in a realistic time. It is known that the reception level fluctuation due to fading is Rayleigh distributed, and Patent Document 2 discloses a method for expressing the fluctuation due to fading without increasing the reception points.
JP-A-9-33584 JP 2001-28570 A

  However, in the radio wave propagation path estimation using the ray tracing method, the estimation accuracy depends on the accuracy of the feature data to be used, and thus the estimation accuracy and the estimation time are constrained.

  Even if processing such as limiting the number of obstacles used for calculation by limiting the propagation path in advance as in Patent Document 1, it is possible to consider obstacles on the road such as automobiles, pedestrians, and roadside trees. If accurate estimation is performed, the calculation time increases.

  In addition, in the calculation amount reduction method for processing the received signal data by statistical / empirical processing as in Patent Document 2, the deterministic estimation result by the feature that is the feature of the ray tracing method depends on the reduction amount. There is a possibility that the distribution will be statistically uniform and do not depend on the city characteristics, and it is impossible to perform high-precision estimation considering obstacles on the road.

  The present invention has been made in view of the above points, and performs real-time high-speed propagation path estimation in consideration of the complexity of the building surface and obstacles on the road without increasing the complexity of the feature data. An object of the present invention is to provide a radio wave propagation path estimation apparatus and a radio wave propagation path estimation method capable of calculating received signal data.

  In order to solve such a problem, the radio wave propagation path estimation apparatus of the present invention includes boundary detection means for searching for obstacles and receivers present on a radiated ray line, and the obstacles on the ray line. If present, the angle formed in the space between the ray and the obstacle surface is obtained based on the inclination of the obstacle surface and the attribute of the obstacle, and the calculation of attenuation due to reflection, transmission and diffraction and the vector orientation of the ray are calculated. A boundary attenuation calculating means for calculating a change amount; and a random number generating means for generating a random number, wherein the boundary attenuation calculating means determines whether or not to perform the calculation based on the random number generated by the random number generating means. Take the configuration to determine.

  The radio wave propagation path estimation method according to the present invention includes a boundary detection step of searching for obstacles and receivers existing on a radiated ray straight line, and an obstacle plane when the obstacle exists on the ray straight line. Boundary for calculating the angle of the space between the ray and the obstacle surface based on the inclination of the object and the obstacle, and calculating the amount of attenuation due to reflection, transmission and diffraction, and the amount of change in the vector direction of the ray It comprises an attenuation calculation step and a random number generation step for generating a random number, and the boundary attenuation calculation step employs a method of determining whether or not to perform the calculation based on the random number generated in the random number generation step.

  According to the present invention, structural irregularities on the building surface, changes in the reflection path by cars on the road, shielding by pedestrians and street trees, etc., that is, increase the calculation time without complicating the feature data. It can be expressed without letting As a result, when the reception level summarizing each reception result data is near the line of sight from the transmission source, Rayleigh distribution is obtained, and at the place near the line of sight from the transmission source, the rice distribution having a different K factor is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a radio wave propagation path estimation apparatus according to Embodiment 1 of the present invention. The radio wave propagation path estimation apparatus shown in FIG. 1 includes a transceiver data storage unit 101, a feature data storage unit 102, a ray emission unit 103, a boundary detection unit 104, a uniform random number generation unit 105, and a random number distribution selection unit. 106, random number distribution weight unit 107, boundary attenuation calculation unit 108, tracking stop determination unit 109, reception propagation path storage unit 110, reception result calculation unit 111, reception result display unit 112, and reception result storage unit 113. And mainly consists of.

  The transmitter / receiver data storage unit 101 stores transmitter and receiver data including parameters such as transmitter and receiver positions, transmission output, antenna gain, antenna pattern, cable loss, carrier wave frequency, and radiation discrete angle. Transmitter data is output to the ray emission unit 103, and receiver data is output to the boundary detection unit 104.

  The feature data storage unit 102 stores feature data such as ground surface information and building information. The feature data storage unit 102 converts the feature data into polygons that form a surface on a three-dimensional (X, Y, Z) orthogonal coordinate system, and the polygons are roads, fields, forests, concrete houses, wooden structures. Stored together with attribute information such as houses, office buildings, and commercial buildings. In the attribute information, propagation characteristics (conductivity, dielectric constant, magnetic permeability) are assigned for each category.

  The polygon and attribute information are output to the boundary detection unit 104 and the random number distribution selection unit 106. In addition, an option switch indicating whether to perform reflection, transmission, or diffraction may be set for each attribute, and information on the switch is output to the boundary attenuation calculation unit 108.

  The ray radiating unit 103 radiates rays one by one discretely from the transmitter position stored in the transceiver data storage unit 101 based on an instruction from the tracking stop determination unit 109. Note that a ray is a line vector and exists on three dimensions (X, Y, Z) like a polygon. A ray has parameters such as attenuation, phase, delay time, transmitter identifier, propagation path, ray transmission angle, ray reception angle, and the like. The parameter information of the emitted ray is output to the boundary detection unit 104.

  The boundary detection unit 104 searches for polygons and receivers that exist on the ray straight line emitted by the ray emission unit 103. The search result in the boundary detection unit 104 is one of the following three cases. The first case is when there is nothing on the ray line. The second case is when the receiver is on a ray line. The third case is a case where a polygon exists on a ray straight line. Polygons existing on the ray straight line become obstacles.

  When the search result is the first case, the boundary detection unit 104 outputs only flag information indicating the “tracking end” state to the tracking stop determination unit 109. Further, when the search result is the second case, the boundary detection unit 104 outputs ray parameter information to the tracking stop determination unit 109 together with flag information indicating a “tracking end” state. In addition, when the search result is the third case, the boundary detection unit 104 outputs the ray parameter information, the obstacle, and the attribute information thereof to the boundary attenuation calculation unit 108.

  The uniform random number generation unit 105 generates a uniform random number from random number initial values set so that propagation path estimation has the same result every time under the same conditions. The random number distribution selection unit 106 selects a random number distribution from the attribute information of the obstacle such as a road, a forest, a wall surface, and the like. The random number distribution weight unit 107 weights the uniform random numbers according to the random number distribution selected by the random number distribution selection unit 106.

  The boundary attenuation calculation unit 108 obtains an angle formed by the space between the ray and the obstacle surface based on the inclination of the obstacle surface and the attribute of the obstacle, calculates an attenuation amount due to reflection, transmission, and diffraction, and a ray vector. Calculate the amount of change in direction. At that time, the boundary attenuation calculation unit 108 determines whether or not to perform the calculation based on the random number output from the random number distribution weight unit 107. Details of the calculation method using random numbers in the boundary attenuation calculation unit 108 will be described later.

  The parameter information of the attenuated ray whose path has been changed is output to the tracking stop determination unit 109 together with the flag information indicating the “tracking” state. When the obstacle plane is an edge formed from a plurality of obstacle planes, attenuation calculation by diffraction, change in vector orientation of rays, and new generation of rays are performed. The newly generated ray is newly registered in the ray emission unit 103 and the tracking stop determination unit 109 as a new ray.

  The tracking stop determination unit 109 outputs information instructing ray emission to the ray emission unit 103, and determines whether or not to stop tracking for the ray input from the boundary detection unit 104 or the boundary attenuation calculation unit 108. Specifically, when the ray flag information is “tracking” (in the case of the third case), the tracking stop determination unit 109 determines whether the tracking condition is satisfied for the ray. Examples of the tracking condition include that the power level of the ray is less than the threshold value, and that the number of reflections, transmissions, or diffractions is within the threshold value. The tracking stop determination unit 109 outputs ray parameter information to the boundary detection unit 104 when the tracking condition is satisfied, and sets the ray flag to the “tracking end” state when the tracking condition is not satisfied. When the tracking target ray flag information is “tracking end” (when the tracking condition is not satisfied in the first case, the second case, and the third case), the tracking stop determination unit 109 determines the next ray. Information indicating the radiation is output to the ray radiation unit 103. Further, in the second case, tracking stop determination section 109 outputs ray parameter information to reception propagation path storage section 110. Then, the tracking stop determination unit 109 stores the total number of rays in advance, and when the number of rays whose flag information is “tracking end” reaches the total number, receives and propagates information indicating that the tracking of all the rays has ended. The data is output to the path storage unit 110.

  The reception propagation path storage unit 110 stores the ray parameter information in association with the receiver, and outputs the stored data to the reception result calculation unit 111 when the tracking of all the rays is completed.

  As shown in FIG. 2, the reception result calculation unit 111 combines the instantaneous reception power of all rays stored in the reception propagation path storage unit 110 for each receiver, and receives reception power, delay spread, angle spread, and the like. Calculate the result.

  The reception result display unit 112 displays the reception result calculated by the reception result calculation unit 111. The reception result storage unit 113 stores the reception result calculated by the reception result calculation unit 111.

  Next, details of a calculation method using random numbers in the boundary attenuation calculation unit 108 will be described.

  Radio waves are attenuated by pedestrians, street trees, etc. existing on the road. A ray colliding with an obstacle such as a roadside tree or a pedestrian is limited to a case where the angle θ between the ground surface and the ray is small. For example, in the case of FIG. 3, a ray E3 (φ) having a large angle θ with the ground surface is reflected by the ground surface and reaches the receiver, but a ray E2 (φ) with a small angle θ formed with the ground surface is When reflecting off the surface, it will collide with trees, pedestrians, etc., and the attenuation will be large and will not reach the receiver.

Therefore, these obstacles can be taken into account by adding or discarding additional attenuation with respect to a ray below that with a certain angle as a threshold. Also, instead of applying a uniform attenuation at a certain threshold value as a boundary, obstacles such as pedestrians and trees are added by adding attenuation depending on the angle between the ground surface and the ray as shown in the following formula (1). Can also be expressed.
L _comp = 1-exp {min (-θ _in + θ _reg , 0) / K} (1)

In Equation (1), Lcomp is the attenuation amount, θ _in is the angle between the ground surface and the ray, θ _reg is the regulation angle (threshold), and K is the inclination correction value.

  Here, since the presence of pedestrians and street trees is random, the boundary attenuation calculation unit 108 determines whether or not to apply these thresholds or the expression (1) based on random numbers from the random number distribution weight unit 107.

  The threshold value and the distribution of random numbers to be used are selected by the random number distribution selection unit 106. The distribution state uses experimental statistical values such as Gaussian distribution, Rayleigh distribution, Poisson distribution and the like.

  In addition, since pedestrians and roadside trees exist only on roads (passages), the random number distribution selection unit 106 determines the presence / absence of calculation in the boundary attenuation calculation unit 108 according to the attribute of the ground surface, and the type and coefficient of statistical distribution. Can be switched.

  In this way, by randomly controlling whether to perform reflection, transmission and diffraction calculations, and whether to change the attenuation according to the incident angle, obstacles such as pedestrians and street trees that exist randomly Even if an object is not created as feature data, it is possible to obtain a simulation result that matches the actual situation.

  The random number output to the boundary attenuation calculation unit 108 is a finite value obtained by weighting the uniform random number generated by the uniform random number generation unit 105 to the random number distribution weight unit 107, and is repeated at a certain period. Therefore, the duplication can be reduced by shifting the start position of the random number with the initial random number. Here, as a method for generating uniform random numbers, a random number generation method using a PN sequence can be cited.

  In addition, there are windows on the wall of the building, and as shown in FIG. 4, the normal wall portion and the window portion have different reflectance, transmittance, etc. The wall of the building is only a wall, not every single window.

  On the other hand, in the present embodiment, in the case of a wall surface attribute, the presence / absence of transmission (type of wall surface) can be switched with a random number along an arbitrary distribution.

  This makes it possible to obtain a simulation result that matches the actual situation without creating windows in the wall surface data of the building. In addition, the random number distribution selection unit 106 can switch not only the presence / absence of a window but also a propagation parameter (conductivity, dielectric constant, magnetic permeability).

  As described above, according to the present embodiment, the complexity of the building surface and the obstacle on the road can be increased without increasing the complexity of the feature data by performing random control of the presence / absence of the obstacle, the attribute of the obstacle, and the like. Considering the above, it is possible to perform high-speed propagation path estimation that is realistic, and to calculate received signal data.

(Embodiment 2)
In Embodiment 2 of the present invention, random numbers are used to determine the direction of reflection. FIG. 5 is a diagram showing a configuration of the radio wave propagation path estimation apparatus according to the present embodiment. In the radio wave propagation path estimation apparatus in FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  5 adds a ray re-radiation unit 201, an attenuation calculation unit 202, an active identifier change unit 203, and a periodic trigger generation unit 204 instead of the boundary attenuation calculation unit 108 to FIG. Adopted the configuration.

  In the case of the third case, the boundary detection unit 104 outputs ray parameter information, obstacles, and attribute information thereof to the ray re-radiation unit 201.

  The ray re-radiating unit 201 determines the traveling direction of the ray hitting the obstacle, the number of scattered divisions, and the divided ray direction according to the random number generated by the random number distribution weight unit 107.

  The attenuation amount calculation unit 202 performs attenuation corresponding to the absolute value difference between the incident angle and the final azimuth angle with respect to the ray whose azimuth is determined by the ray re-radiation unit 201. The ray attenuated by the attenuation amount calculation unit 202 is newly registered in the tracking stop determination unit 109 as a new ray.

  Here, for example, the following two examples are given as physical meanings in which the direction is randomly determined by the ray re-radiating unit 201 and attenuated by the attenuation amount calculating unit 202. As a first example, as shown in FIG. 6, a certain ray is shielded on a road by a reflector such as an automobile and a signboard, and the ray is received by a certain receiver. In FIG. 6, the ray E2 (φ) corresponds to this. As a second example, as shown in FIG. 7, the surface of the building is not mirror-like, and there are entrances and overhanging roofs of the building, and irregular reflection is performed at those portions.

  The direction of irregular reflection emitted by the ray re-radiation unit 201 is not necessarily one at a time. A case where light is reflected in a plurality of directions at one reflection point will be described with reference to FIG. In FIG. 8, a track is depicted as a reflector. However, the shape of the track is not a simple rectangular parallelepiped, but has a complicated shape. Of course, the truck moves with time. This means that the direction of reflection is not unique. In the case of FIG. 8, for simplicity, the original ray is (O1), and there are three rays (R1 to R3) re-radiated by the track.

  In this case, a plurality of re-radiated rays cannot exist simultaneously. For this reason, the ray re-radiated by the ray re-radiating unit 201 is given the unique active identifier determined by the ray re-radiating unit 201 based on the identification number of the original ray and the random number. 110. In the reception result calculation unit 111, only rays having a positive active identifier are subjected to calculation.

  The re-radiated ray identified by having the original ray identification number is changed by changing the ray whose active identifier is positive in the active identifier changing unit 203 according to the random number, thereby searching for the ray. You can get a different result after is finished.

  This means that a propagation path change caused by a moving reflector such as an automobile can be instantly represented without performing a ray search process, which is a time-consuming and redundant process.

  In other words, by changing the ray re-radiated by the active identifier changing unit 203 for each trigger generated by the periodic trigger generating unit 204 according to a random number, even when the receiver is stationary, such as a car, a pedestrian, etc. An estimated value of a dynamic propagation state due to the movement of the surrounding environment can be acquired.

  The active identifier changing unit 203 can express a phenomenon called diffuse reflection by not only selecting one ray for a ray derived from one original ray but also weighting each ray. . As shown in FIG. 9, the diffuse reflection refers to a state in which the ray reflected by the roughness of the reflecting surface diffuses around the regular reflected wave. The attenuation is performed so that the weight multiplied by the incident angle and the reflected direction does not exceed the potential of the original ray in the total reflected wave.

  Thus, according to the present embodiment, it is possible to add variation to the theoretical value from the random number distribution along the attribute to which the obstacle existing at the boundary belongs, according to the reflection direction of the radio wave at the boundary, and diffuse reflection or diffuse reflection. All rays can be saved and used to create dynamic reception result data.

(Embodiment 3)
FIG. 10 is a diagram showing the configuration of the invention according to Embodiment 3 of the present invention. In the radio wave propagation path estimation apparatus in FIG. 10, the same components as those in FIG. 5 are assigned the same reference numerals as those in FIG.

  The radio wave propagation path estimation apparatus of FIG. 10 employs a configuration in which a reception movement path storage unit 301 and a reception movement path selection unit 302 are added to FIG.

  In the third embodiment, the propagation state at an arbitrary position is calculated in advance according to the first embodiment or the second embodiment at an arbitrary grid interval and stored in the reception propagation path storage unit 110. The size of the grid is set as one parameter of data for transmission / reception, for example.

  The reception movement path storage unit 301 stores the grid position and outputs information indicating the grid number corresponding to the input movement path of the receiver to the reception movement path selection unit 302.

  The periodic trigger generation unit 204 generates a trigger corresponding to the update interval of the reception result data that can be calculated from the moving speed of the receiver and the grid interval.

  As illustrated in FIG. 11, the reception movement path selection unit 302 updates the reception result data of the grid for each trigger.

  Here, the movement route of a mobile phone caller such as a pedestrian or an automobile is not necessarily unique. Therefore, the fluctuation due to the movement can be given by giving the reception movement path selection unit 302 the fluctuation multiplied by the random number from the random number distribution weight part 107. In addition, by continuously changing the position of the grid generated uniformly within the simulation range, statistical movement characteristics in the regional characteristics can be obtained without having an absolute movement path by the movement path input. be able to.

  Note that the fluctuation of the propagation data created in the first and second embodiments is a fluctuation due to the external environment that occurs even when the receiver is stationary, and the fluctuation of the propagation data created in the third embodiment is received. This is a variation that occurs as the machine moves.

(Other embodiments)
In the above description of the embodiment, the ray launching method in which rays generated discretely from the ray radiating unit 103 search for obstacles has been described. However, the present invention provides an imaging method for searching for combinations of all obstacles. Can also be applied.

  In this case, as illustrated in FIG. 12, an all combination extraction unit 401 and a virtual image generation unit 402 are added to FIG. 1 instead of the ray radiating unit 103.

  The all combination extraction unit 401 extracts and stores all combinations of a transmitter, a receiver, an obstacle, and a diffraction edge.

  The virtual image generation unit 402 generates a virtual image of the transmission point for each combination extracted by the all combination extraction unit 401.

  The boundary detection unit 104 detects a reflection point or a diffraction point.

  INDUSTRIAL APPLICABILITY The present invention is suitable for use in designing a spatial arrangement of a wireless system due to a city-dependent space reproduction capability. In addition, the present invention is capable of reproducing regional characteristics, an arbitrary traveling speed of the own vehicle, and a dynamic propagation environment by movement of the surrounding environment, and adapting to the environment using a device using a plurality of antenna elements. It is suitable for use in developing a wireless communication system.

The block diagram which shows the structure of the radio wave propagation path estimation apparatus which concerns on Embodiment 1 of this invention. Diagram explaining rays that reach the receiving point and their combination Diagram explaining the attenuation effect of obstacles present on the road Diagram explaining the attenuation effect due to the difference in wall attributes The block diagram which shows the structure of the electromagnetic wave propagation path estimation apparatus which concerns on Embodiment 2 of this invention. The figure explaining the irregular reflection by the obstacle which exists on the road The figure explaining the irregular reflection resulting from the structure of the obstacle surface Diagram explaining dynamic diffuse reflection by obstacles existing on the road Diagram explaining diffuse reflection The block diagram which shows the structure of the radio wave propagation path estimation apparatus which concerns on Embodiment 3 of this invention. A diagram explaining the principle of fluctuation due to movement of the receiver The figure which shows the structure of the electromagnetic wave propagation path estimation apparatus in other embodiment of this invention. Diagram explaining the ray launching method

Explanation of symbols

Reference Signs List 101 transceiver data storage unit 102 feature data storage unit 103 ray emission unit 104 boundary detection unit 105 uniform random number generation unit 106 random number distribution selection unit 107 random number distribution weight unit 108 boundary attenuation calculation unit 109 tracking stop determination unit 110 reception propagation path Storage unit 111 Reception result calculation unit 112 Reception result display unit 113 Reception result storage unit 201 Ray re-radiation unit 202 Attenuation amount calculation unit 203 Active identifier change unit 204 Period trigger generation unit 301 Reception movement path storage unit 302 Reception movement path selection unit

Claims (6)

Boundary detection means for searching for obstacles and receivers present on the line of radiated rays;
When the obstacle exists on a straight line of the ray, the angle formed in the space between the ray and the obstacle surface is obtained based on the inclination of the obstacle surface and the attribute of the obstacle, and reflection, transmission, and diffraction are used. Boundary attenuation calculating means for calculating the amount of attenuation and calculating the amount of change in the vector direction of the ray,
Random number generating means for generating a random number,
The boundary attenuation calculation means is a radio wave propagation path estimation apparatus that determines whether or not to perform the calculation based on a random number generated by the random number generation means.   2. The radio wave propagation path estimating apparatus according to claim 1, wherein the boundary attenuation calculating means determines whether or not to perform attenuation depending on an angle based on a random number generated by the random number generating means.   The radio wave propagation path estimation apparatus according to claim 1 or 2, wherein the boundary attenuation calculation unit determines an attribute of an obstacle based on a random number generated by the random number generation unit. Boundary detection means for searching for obstacles and receivers present on the line of radiated rays;
Random number generating means for generating random numbers;
Ray re-radiating means for determining the traveling direction of the ray hitting the obstacle and the number of scattered divisions, the direction of the divided rays according to the random number generated by the random number generating means,
A radio wave propagation path estimation apparatus comprising attenuation amount calculation means for performing attenuation according to an absolute value difference between an incident angle and a final azimuth angle with respect to a ray whose azimuth is determined by the ray re-radiation means. A boundary detection step for searching for obstacles and receivers present on a line of radiated rays;
When the obstacle exists on a straight line of the ray, the angle formed in the space between the ray and the obstacle surface is obtained based on the inclination of the obstacle surface and the attribute of the obstacle, and reflection, transmission, and diffraction are used. Boundary attenuation calculation process for calculating the amount of attenuation and calculating the amount of change in the vector direction of the ray,
A random number generation step for generating a random number,
The radio wave propagation path estimation method in which the boundary attenuation calculation step determines whether or not to perform the calculation based on the random number generated in the random number generation step. Boundary detection procedure to search for obstacles and receivers present on the line of radiated rays;
When the obstacle exists on a straight line of the ray, the angle formed in the space between the ray and the obstacle surface is obtained based on the inclination of the obstacle surface and the attribute of the obstacle, and reflection, transmission, and diffraction are used. Boundary attenuation calculation procedure for calculating the amount of attenuation and calculating the amount of change in the vector direction of the ray,
A random number generation procedure for generating a random number,
The boundary attenuation calculation procedure is a simulation program that determines whether or not to perform the calculation based on the random number generated in the random number generation procedure.

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