Propagation path search system, information processing device, propagation path search method, and information processing program

Abstract

To search for a propagation path having the smallest loss quickly and accurately according to a set ratio of propagation paths that contribute to the propagation of scattered radio waves.SOLUTION: A propagation path search system obtains a first coefficient set based on a ratio of a propagation path contributing to the propagation of radio waves and an area of a flat plate of each structure that scatters the radio waves, and a second coefficient set based on the ratio of the propagation path contributing to the propagation of the radio waves and a scattering frequency by each structure, calculates s propagation loss of the radio waves among a transmitting point, a receiving point, and each structure based on a predetermined scattering frequency for each structure, calculates, based on each propagation loss, an objective function that is the propagation loss of the propagation path, sets each function obtained by multiplying the calculated objective function by the first coefficient, multiplying a predetermined scattering constraint condition by the second coefficient and adding them, performs processing for minimizing the set function, and identifies the propagation path based on the minimized result.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a propagation path searching system, an information processing device, a propagation path searching method, and an information processing program. [Background technology]

[0002] In designing wireless communication systems, it is important to understand the radio wave propagation characteristics within a service area through simulation. In addition, there are many system parameters that need to be optimized in order to simulate radio wave propagation characteristics. Therefore, simulation of radio wave propagation characteristics requires high speed as well as accuracy.

[0003] One method for simulating the propagation characteristics of radio waves is the ray tracing method, which regards radio waves emitted from a transmitting point as rays, searches for rays that reach a receiving point after being scattered by reflection, transmission, diffraction, etc., and calculates propagation characteristics such as received power, propagation delay, and arrival angle at the receiving point.

[0004] In addition, the ray tracing method includes the imaging method, which uses geometric optics to find the reflection point from the combination of the transmitting and receiving points and the reflecting surface, and the ray launching method, which launches rays discretely from the transmitting point at fixed angles and tracks their trajectories to search for the rays that reach the receiving point. The imaging method is the method that can perform simulations with high accuracy.

[0005] Also, in a quantum computing simulation using a radio wave propagation QUBO (Quadratic unconstrained binary optimization) model, a technique is known in which an objective function for searching a propagation loss criterion is defined as "all propagation losses between transmitter and receiver" (for example, see Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Tetsuro Imai and 3 others, "Modeling for Radio Propagation Analysis by Quantum Computing (2)", Institute of Electronics, Information and Communication Engineers, January 2022, IEICE Technical Report, vol. 121, no. 330, A-P2021-157, pp. 128-133 Summary of the Invention [Problem to be solved by the invention]

[0007] In simulating the propagation characteristics of radio waves, various methods are required to prevent the amount of calculations from exploding due to an increase in the number of combinations required to quickly search for rays that contribute to the propagation characteristics. As mentioned above, the imaging method can accurately find the rays that reach the receiving point.

[0008] However, because ray searching requires combined calculations of the faces and edges of structures, the amount of calculations increases exponentially as the number of reflections, transmissions, and diffractions (hereafter simply referred to as scattering) that must be considered increases.

[0009] For example, if the number of faces and edges of a structure within the calculation range is M and the number of reflections, etc. to be considered is a maximum of N, the amount of calculation (number of combinations) is expressed by the following formula (1).

[0010]

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[0011] In addition, these combinations include many rays that have large propagation losses and do not contribute to the propagation characteristics, and the efficiency of the computational load is not good. Therefore, the challenge is to quickly search for rays that contribute to the propagation characteristics.

[0012] Conventionally, objective functions can be converted into a model generally known as the Ising model, and high-speed calculations are possible using quantum annealing machines that are already commercially available.

[0013] However, because the objective function cannot hold three states, the weights given are limited to the propagation distance and scattering loss calculated from two states. In other words, there was a problem in that it was not possible to faithfully reproduce the scattering phenomenon from structures in the actual radio wave propagation environment.

[0014] Specifically, in the scattering model with the directional pattern shown in Figure 1, the scattering of radio waves depends on the angle of incidence and the scattering angle, so it was not possible to calculate the propagation characteristics using a quantum annealing machine. Figure 1 is a diagram showing a scattering model based on the ER (Single Lobe) type propagation model on a flat plate.

[0015] In Fig. 1, the size of the flat plate is S and the scattering coefficient is Γ (0≦Γ≦1). In this case, the propagation model when scattering occurs once is expressed by the following equation (2).

[0016]

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[0017] In addition, since the reflection angle θr is determined from the incidence angle θin, the scattering pattern G(θr, θs) is replaced with G(θin, θs), and the propagation model is expressed by the following equation (3).

[0018]

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[0019] However, the Propagation QUBO model consists of an objective function and multiple constraints, and the relative strength of these is adjusted by weighting coefficients. Therefore, the accuracy of radio wave propagation analysis using the Propagation QUBO model depends on the weighting coefficients that are set, and it may not be possible to derive a solution that satisfies the constraints.

[0020] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a propagation path searching system, an information processing device, a propagation path searching method, and an information processing program that are capable of accurately and quickly searching for a propagation path that minimizes loss in accordance with a set ratio of the propagation paths that contribute to the propagation of radio waves when radio waves are scattered. [Means for solving the problem]

[0021] A propagation path searching system according to one embodiment of the present invention is a propagation path searching system that searches for a propagation path of a radio wave that is emitted from a transmission point and scattered by a plurality of structures before reaching a reception point, the propagation path searching system including: an acquisition unit that acquires a ratio of the propagation path that contributes to the propagation of the radio wave and a first coefficient that is set based on an area of ​​a flat plate of each of the structures that scatters the radio wave; and a second coefficient that is set based on a ratio of the propagation path that contributes to the propagation of the radio wave and a number of scatterings by each of the structures; and a calculation unit that calculates a propagation loss of the radio wave between the transmission point, the reception point, and each of the structures based on a number of scatterings that is predetermined for each of the structures. an objective function calculation unit that calculates an objective function which is the propagation loss of the propagation path from the transmission point to the reception point based on each of the propagation losses calculated by the propagation loss calculation unit; a function setting unit that multiplies the objective function calculated by the objective function calculation unit by the first coefficient and sets a function obtained by multiplying a predetermined scattering constraint condition by the second coefficient and adding the result; a minimization processing unit that performs processing to minimize the function set by the function setting unit; and a propagation path identification unit that identifies the propagation path from the transmission point to the reception point based on a result of minimization by the minimization processing unit.

[0022] Moreover, an information processing device according to one embodiment of the present invention is an information processing device that performs processing to search for a propagation path of a radio wave that is emitted from a transmission point and scattered by a plurality of structures before reaching a reception point, the information processing device including: an acquisition unit that acquires a ratio of the propagation paths that contribute to the propagation of the radio wave and a first coefficient set based on an area of ​​a flat plate of each of the structures that scatters the radio wave, and a second coefficient set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and a number of scatterings by each of the structures; and a calculation unit that calculates a current between the transmission point, the reception point, and each of the structures based on a number of scatterings predetermined for each of the structures. the propagation path identification unit acquiring a result of minimizing the function set by the function setting unit, and identifying the propagation path from the transmission point to the reception point by acquiring a propagation path identification unit that identifies ...

[0023] Moreover, in a propagation path searching method according to one embodiment of the present invention, a propagation path searching system including an information processing device and an arithmetic device searches for a propagation path of a radio wave that is emitted from a transmission point and scattered by a plurality of structures before reaching a reception point, the information processing device includes an acquisition step of acquiring a ratio of the propagation path contributing to the propagation of the radio wave and a first coefficient set based on an area of ​​a flat plate of each of the structures that scatters the radio wave, and a second coefficient set based on a ratio of the propagation path contributing to the propagation of the radio wave and a number of times of scattering by each of the structures; The method includes a propagation loss calculation step of calculating a propagation loss of radio waves between each of the structures; an objective function calculation step of calculating an objective function which is the propagation loss of the propagation path from the transmission point to the reception point based on each of the propagation losses calculated in the propagation loss calculation step; a function setting step of multiplying the objective function calculated in the objective function calculation step by the first coefficient, multiplying a predetermined scattering constraint condition by the second coefficient and adding the result to a calculation device; and a propagation path identification step of acquiring a result of the calculation device minimizing the function set in the function setting step and identifying the propagation path from the transmission point to the reception point.

[0024] Moreover, an information processing program according to one embodiment of the present invention is an information processing program executed by an information processing device that performs processing to search for a propagation path of a radio wave that is emitted from a transmission point and scattered by a plurality of structures before reaching a reception point, the information processing program including: an acquisition unit that acquires a ratio of the propagation path that contributes to the propagation of the radio wave and a first coefficient set based on an area of ​​a flat plate of each of the structures that scatters the radio wave; and a second coefficient set based on a ratio of the propagation path that contributes to the propagation of the radio wave and a number of scatterings by each of the structures; and a calculation unit that calculates a propagation loss of the radio wave between the transmission point, the reception point, and each of the structures based on a number of scatterings predetermined for each of the structures. an objective function calculation unit that calculates an objective function which is the propagation loss of the propagation path from the transmission point to the reception point based on each of the propagation losses calculated by the propagation loss calculation unit; a function setting unit that multiplies the objective function calculated by the objective function calculation unit by the first coefficient and multiplies a predetermined scattering constraint condition by the second coefficient and adds the result to a calculation device; and a propagation path identification unit that obtains a result of the calculation device minimizing the function set by the function setting unit and identifies the propagation path from the transmission point to the reception point. Effect of the Invention

[0025] According to the present invention, when radio waves are scattered, it is possible to accurately and quickly search for a propagation path that minimizes loss in accordance with a set ratio of the propagation paths that contribute to the propagation of the radio waves. [Brief description of the drawings]

[0026] [Figure 1] FIG. 13 is a diagram showing a scattering model based on an ER type propagation model on a flat plate. [Diagram 2] 1 is a diagram illustrating a case where propagation loss occurs in radio waves due to multiple scattering; [Diagram 3] FIG. 2 is a diagram illustrating an example of a hardware configuration of a propagation path searching system according to an embodiment. [Figure 4]FIG. 2 is a functional block diagram illustrating an overview of functions of a propagation path searching system according to an embodiment. [Diagram 5] Graph (a) shows the relationship between the area of ​​the flat plate of each structure and the weighting coefficient, and graph (b) shows the relationship between the number of scatterings caused by multiple structures and the weighting coefficient. [Figure 6] Graph (a) shows the violation rate γ set for the propagation path searching system and the violation rate γ obtained by a regression equation based on the area size, and graph (b) shows the violation rate γ set for the propagation path searching system and the violation rate γ obtained by a regression equation based on the number of scatterings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In describing a propagation path searching system according to an embodiment, first, a propagation loss model in which propagation loss occurs in radio waves due to multiple scattering will be described.

[0028] Figure 2 is a diagram illustrating a case where radio wave propagation loss occurs due to multiple scattering. The propagation loss model of radio wave due to N scatterings is expressed by the following formula (4), and can be shown as the following formula (5). Here, the propagation model shown in Figure 1 is used.

[0029]

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[0030]

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[0031] Here, the transmission power P T , received power P R , transmission frequency F, transmission antenna gain G T , receiving antenna gain G R , the number of scatterings N, the number of search paths Np, a constant K determined by the frequency etc., and a constant α related to the directivity pattern r It states that:

[0032] The transmitting and receiving positions are set using, for example, Cartesian coordinates or longitude and latitude. The size S of the flat plate is calculated from information acquired from, for example, a database of structures. The scattering coefficient Γ is set to a different value for each material of the structure.

[0033] Next, a propagation path searching system 10 according to an embodiment will be described with reference to the drawings. Fig. 3 is a diagram showing an example of a hardware configuration of the propagation path searching system 10 according to an embodiment. As shown in Fig. 3, the propagation path searching system 10 includes, for example, an information processing device 20 and a calculation device 30. The propagation path searching system 10 searches for a propagation path of a radio wave that is emitted from a transmitting point and scattered by a plurality of structures before arriving at a receiving point.

[0034] The information processing device 20 is a computer that transmits data to the calculation device 30 and acquires the results of calculations performed by the calculation device 30, and for example, inputs a combinatorial optimization problem to the calculation device 30. For example, the information processing device 20 has a calculation condition setting function for searching for a propagation path, a propagation matrix / vector generation function, and a propagation QUBO model generation function.

[0035] Then, the information processing device 20 performs a process of searching for a propagation path of a radio wave that is emitted from a transmission point Tx and scattered by a plurality of structures before arriving at a reception point Rx, for example.

[0036] For example, the information processing device 20 has an input unit 200, an output unit 201, a communication unit 202, a CPU 203, a memory 204, and a HDD 205 connected via a bus 206, and is capable of inputting and outputting data to and from a storage medium 207.

[0037] The input unit 200 is, for example, a keyboard and a mouse. The output unit 201 is, for example, a display device such as a display. The communication unit 202 is, for example, a wired or wireless network interface, and transmits and receives data to and from the arithmetic device 30.

[0038] The CPU 203 controls each unit constituting the information processing device 20 and performs processes such as generating data having a data structure described later. The memory 204 and the HDD 205 constitute a storage unit that stores data. The storage medium 207 is capable of storing programs and data for executing the functions of the information processing device 20.

[0039] The arithmetic device 30 is, for example, a arithmetic device that calculates the propagation characteristics of radio waves for each propagation path, and is, for example, a computer that performs arithmetic processing using an interconnected neural network, or a quantum annealing machine that solves combinatorial optimization problems using a quantum annealing method.

[0040] For example, the arithmetic device 30 includes a communication unit 300, a control unit 302, and an arithmetic processing unit 304. The communication unit 300 is, for example, a wired or wireless network interface, and transmits and receives data to and from the information processing device 20.

[0041] The control unit 302 controls each unit constituting the arithmetic device 30. When the arithmetic device 30 is a quantum annealing machine, the arithmetic processing unit 304 includes a quantum processing unit (QPU) (not shown). In this case, the control unit 302 also performs pulse control for the arithmetic processing unit 304 and observation of the arithmetic results. When the arithmetic processing unit 304 is a computer that solves combinatorial optimization problems using semiconductors, it includes a field programmable gate array (FPGA), or a CPU and a graphics processing unit (GPU), not shown.

[0042] The architecture constituting the channel searching system 10 is not limited to the example shown in Fig. 3, and may be configured as an integrated system. The arithmetic device 30 may be a simulated annealing (SA) machine.

[0043] Next, a description will be given of functions of the propagation path searching system 10. Fig. 4 is a functional block diagram illustrating an outline of functions of the propagation path searching system 10 according to an embodiment. As shown in Fig. 4, the propagation path searching system 10 includes, for example, an acquisition unit 400, a propagation loss calculation unit 402, an objective function calculation unit 404, a function setting unit 406, a minimization processing unit 408, and a propagation path identification unit 410.

[0044] The acquisition unit 400 is configured in, for example, the information processing device 20, and acquires map data including structures present within the area where radio waves are transmitted from a transmission point Tx to a reception point Rx from a structure database (not shown) or the like, and outputs the map data to the propagation loss calculation unit 402.

[0045] Moreover, the acquiring unit 400 acquires information such as setting items required for calculating the propagation loss and the like, and outputs the information to the function setting unit 406 .

[0046] For example, the acquisition unit 400 acquires a first coefficient (coefficient K0 described later) set based on the ratio of the propagation paths contributing to the propagation of the radio waves (substantially indicated by a violation rate γ described later) and the area of ​​each flat plate of the structure that scatters the radio waves, and outputs the first coefficient to the function setting unit 406.

[0047] In addition, the acquisition unit 400 acquires the proportion of the propagation paths contributing to the propagation of the radio wave (essentially indicated by the violation rate γ described later) and a second coefficient (coefficient K1 described later) set based on the number of scatterings by each structure, and outputs it to the function setting unit 406.

[0048] The propagation loss calculation unit 402 is configured in, for example, the information processing device 20, and calculates the propagation loss of radio waves between the transmission point Tx, the reception point Rx, and each of the structures based on the number of scattering times predetermined for each of the structures, and outputs each of the calculated propagation losses to the objective function calculation unit 404.

[0049] The objective function calculation unit 404 is configured in, for example, the information processing device 20, and calculates an objective function that is the propagation loss of the propagation path from the transmission point Tx to the reception point Rx based on each propagation loss calculated by the propagation loss calculation unit 402, and outputs the calculated objective function to the function setting unit 406. The objective function will be described later. Furthermore, when a propagation path specified by the propagation path specifying unit 410 has already been identified, the objective function calculation unit 404 performs calculation based on the specified propagation path.

[0050] The function setting unit 406 is configured in, for example, the information processing device 20, and sets, for the minimization processing unit 408, a function obtained by multiplying the objective function calculated by the objective function calculation unit 404 by the first coefficient described above, and by multiplying a predetermined scattering constraint condition by the second coefficient described above and adding the resultant function (see equation (6) described later).

[0051] Here, the function setting unit 406 includes in the scattering constraint conditions (described later) that the radio waves are necessarily scattered a predetermined number of times, that the flat plate of the structure to which the radio waves are scattered each time is unique, that the radio waves are not continuously scattered by the same flat plate of the structure, and that the transmitting point Tx and the receiving point Rx are the start point and end point of the propagation path.

[0052] The minimization processing unit 408 is configured in, for example, the arithmetic device 30 , performs processing to minimize the function set by the function setting unit 406 , for example, solving a combinatorial optimization problem, and outputs the result to the channel identification unit 410 .

[0053] The propagation path identification unit 410 is configured in, for example, the information processing device 20, and identifies the propagation path from the transmission point Tx to the reception point Rx based on the result of minimization by the minimization processing unit 408, and outputs it via, for example, the output unit 201 (Figure 3).

[0054] Next, a specific example of the operation of the propagation path searching system 10 will be described. For example, the propagation path searching system 10 searches for rays corresponding to radio waves emitted from a transmission point Tx and arriving at a reception point Rx.

[0055] For example, suppose that there are structures A to G between a transmission point Tx and a reception point Rx. In addition, the path of a ray that can be considered as a propagation path includes, for example, the propagation path of the transmission point Tx → structure A → structure B → structure D → structure G → reception point Rx.

[0056] Then, the propagation path searching system 10 can identify the propagation path that contributes most to the propagation of radio waves by minimizing a function (energy function) H expressed by the following equation (6).

[0057]

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[0058] Here, L is an objective function describing the physical quantity to be evaluated. J1, J2, and J3 indicate the constraint conditions for the propagation path search. K0, K1, K2, and K3 are positive weighting coefficients that adjust the strength of different constraint conditions.

[0059] The propagation path searching system 10 uses the following expressions as variables to represent the propagation paths, with the number of structures (structure i, structure j, etc.) in the search area being M and the number of scatterings (number of reflections, etc.) being N. For example, the propagation path searching system 10 uses q ik ∈{1,0}: Binary variable, which is set to “1” when the kth plate of the structure is reached, and “0” otherwise.

[0060] The constraint J1 is that "radio waves are always scattered N times, and each time, there is only one flat plate that scatters the waves," and is expressed by the following equation (7).

[0061]

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[0062] Moreover, the constraint J2 is that "radio waves are not continuously scattered by the same flat plate" and is expressed by the following equation (8).

[0063]

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[0064] Constraint J3 is expressed by the following formula (9) assuming that "the transmitting point Tx and the receiving point Rx are used only at the starting point and the ending point of the path, respectively."

[0065]

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[0066] In addition, the inventors have found that, based on prior simulation values ​​using, for example, 3D CAD of an actual propagation environment, the governing parameters for the weighting coefficient in the above equation (6) are the surface area of ​​the structure that scatters the radio waves (area size of a flat plate) and the number of times the radio waves are scattered by multiple structures.

[0067] Therefore, the inventor formulated the relational expression between the weighting coefficients and the ratio of the propagation paths contributing to the propagation of radio waves (substantially indicated by the violation rate γ described later) by multiple regression analysis. For example, the inventor uses a 3D CAD of the actual propagation environment to obtain the weighting coefficients K0 and K1 in the above formula (6) by the following steps A to D.

[0068] A: Let the magnification rate be ρ, and change the transmission point Tx, reception point Rx, and coordinates (x, y) of the structure to (ρx, ρy). Also, define the violation rate γ as the number of violation patterns / total number of patterns × 100[%], and accumulate the evaluation results of the violation rate γ after M trials while changing the magnification rate ρ and the weighting coefficient K0.

[0069] B: While varying the number of scatterings N and the weighting coefficient K1, the evaluation results of the violation rate γ for the number of trials M are accumulated.

[0070] C: Using the results of A, multiple regression analysis is performed as shown in the following formula (10) to obtain the relationship between the violation rate γ and the weighting coefficient K0.

[0071]

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[0072] Using the results of D:B, ​​multiple regression analysis is performed as shown in the following formula (11), and a relational expression between the violation rate γ and the weighting coefficient K1 is obtained.

[0073]

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[0074] Then, the inventors substitute the desired violation rates γ into the above equations (10) and (11) in a number of different environments to calculate weighting coefficients.

[0075] Fig. 5 shows the relationship between the area (area size) of the flat plate of each structure and the weighting coefficient K0, and the relationship between the number of scatterings caused by multiple structures and the weighting coefficient K1. Fig. 5(a) is a graph showing the relationship between the area of ​​the flat plate of each structure (displayed at a magnification ratio ρ corresponding to the area size) and the weighting coefficient K0. Fig. 5(b) is a graph showing the relationship between the number of scatterings N caused by multiple structures and the weighting coefficient K1.

[0076] For example, the weighting coefficients K0 and K1 are expressed by the following equations (12) and (13).

[0077]

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[0078] Fig. 6 is a diagram showing the violation rate γ set for the propagation path searching system 10 and the violation rate γ obtained by the regression equation. Fig. 6(a) is a graph showing the violation rate γ set for the propagation path searching system 10 and the violation rate γ obtained by the regression equation based on the area size. Fig. 6(b) is a graph showing the violation rate γ set for the propagation path searching system 10 and the violation rate γ obtained by the regression equation based on the number of scatterings.

[0079] The violation rate γ can be set as desired for the channel tracing system 10 in any of the cases shown in FIG.

[0080] That is, in the propagation path searching system 10, the acquisition unit 400 acquires the weighting coefficients K0 and K1 calculated in advance, and performs a propagation path search by a quantum annealer or the like using a propagation QUBO model using the weighting coefficients K0 and K1 acquired by the acquisition unit 400. Then, the propagation path searching system 10 searches for one desired propagation path by minimizing the energy function H.

[0081] In this way, the propagation path searching system 10 obtains a first coefficient (K0) set based on the proportion of the propagation paths contributing to the propagation of radio waves and the area of ​​each flat plate of the structure that scatters the radio waves, and a second coefficient (K1) set based on the proportion of the propagation paths contributing to the propagation of radio waves and the number of scatterings by each structure, and performs a propagation path search using a propagation QUBO model using K0 and K1. Therefore, when radio waves are scattered, it is possible to accurately and quickly search for a propagation path with the minimum loss according to the set proportion of the propagation paths contributing to the propagation of the radio waves.

[0082] The above-mentioned function H can be converted into a model generally known as the Ising model. In other words, the above-mentioned function H can be applied to interconnected neural networks (Hopfield networks) and quantum annealing machines to solve combinatorial optimization problems, making it highly versatile and enabling high-speed calculations.

[0083] In this way, the propagation path searching system 10 can suitably apply the search for radio wave propagation paths as a combinatorial optimization problem to QUBO, and can quickly search for radio wave propagation paths according to the setting of constraint conditions. [Explanation of symbols]

[0084] 10 ··· propagation path searching system, 20 ··· information processing device, 30 ··· calculation device, 200 ··· input unit, 201 ··· output unit, 202 ··· communication unit, 203 ··· CPU, 204 ··· memory, 205 ··· HDD, 206 ··· bus, 207 ··· storage medium, 300 ··· communication unit, 302 ··· control unit, 304 ··· calculation processing unit, 400 ··· acquisition unit, 402 ··· propagation loss calculation unit, 404 ··· objective function calculation unit, 406 ··· function setting unit, 408 ··· minimization processing unit, 410 ··· propagation path identification unit

Claims

1. A propagation path searching system for searching a propagation path of a radio wave that is emitted from a transmitting point and scattered by a plurality of structures before reaching a receiving point, comprising: an acquisition unit that acquires a first coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and an area of ​​each flat plate of the structure that scatters the radio wave, and a second coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and a number of scatterings caused by each of the structures; a propagation loss calculation unit that calculates a propagation loss of radio waves between the transmitting point, the receiving point, and each of the structures based on a predetermined number of scattering times for each of the structures; an objective function calculation unit that calculates an objective function that is a propagation loss of a propagation path from the transmission point to the reception point based on each of the propagation losses calculated by the propagation loss calculation unit; a function setting unit that sets a function by multiplying the objective function calculated by the objective function calculation unit by the first coefficient and by multiplying a predetermined scattering constraint condition by the second coefficient and adding the result; a minimization processing unit that performs processing to minimize the function set by the function setting unit; a propagation path specifying unit that specifies a propagation path from the transmission point to the reception point based on a result of minimization by the minimization processing unit; A propagation path searching system comprising:

2. An information processing device that performs processing to search for a propagation path of a radio wave that is emitted from a transmitting point and scattered by a plurality of structures before arriving at a receiving point, an acquisition unit that acquires a first coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and an area of ​​each flat plate of the structure that scatters the radio wave, and a second coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and a number of scatterings caused by each of the structures; a propagation loss calculation unit that calculates a propagation loss of radio waves between the transmitting point, the receiving point, and each of the structures based on a predetermined number of scattering times for each of the structures; an objective function calculation unit that calculates an objective function that is a propagation loss of a propagation path from the transmission point to the reception point based on each of the propagation losses calculated by the propagation loss calculation unit; a function setting unit that multiplies the objective function calculated by the objective function calculation unit by the first coefficient, and multiplies a predetermined scattering constraint condition by the second coefficient and adds the result to a function, and sets the function to a calculation device; a propagation path specifying unit that obtains a result of minimizing the function set by the function setting unit by the arithmetic device and specifies a propagation path from the transmission point to the reception point; 13. An information processing device comprising:

3. A propagation path searching method in which a propagation path searching system including an information processing device and an arithmetic device searches for a propagation path of a radio wave that is emitted from a transmitting point and scattered by a plurality of structures before arriving at a receiving point, comprising: The information processing device, an acquisition step of acquiring a first coefficient set based on a ratio of the propagation paths contributing to the propagation of the radio wave and an area of ​​each flat plate of the structure that scatters the radio wave, and a second coefficient set based on a ratio of the propagation paths contributing to the propagation of the radio wave and a number of scatterings caused by each of the structures; a propagation loss calculation step of calculating a propagation loss of radio waves between the transmitting point, the receiving point, and each of the structures based on a predetermined number of scattering times for each of the structures; an objective function calculation step of calculating an objective function that is a propagation loss of a propagation path from the transmitting point to the receiving point based on each of the propagation losses calculated in the propagation loss calculation step; a function setting step of multiplying the objective function calculated by the objective function calculation step by the first coefficient, and multiplying a predetermined scattering constraint condition by the second coefficient and adding the result to a function, and setting the function to a calculation device; a propagation path identifying step of acquiring a result of minimizing the function set by the calculation device in the function setting step and identifying a propagation path from the transmission point to the reception point; A propagation path searching method comprising the steps of:

4. An information processing program executed by an information processing device that performs processing to search for a propagation path of a radio wave that is emitted from a transmitting point and scattered by a plurality of structures before arriving at a receiving point, an acquisition unit that acquires a first coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and an area of ​​each flat plate of the structure that scatters the radio wave, and a second coefficient that is set based on a ratio of the propagation paths that contribute to the propagation of the radio wave and a number of scatterings caused by each of the structures; a propagation loss calculation unit that calculates a propagation loss of radio waves between the transmitting point, the receiving point, and each of the structures based on a predetermined number of scattering times for each of the structures; an objective function calculation unit that calculates an objective function that is a propagation loss of a propagation path from the transmission point to the reception point based on each of the propagation losses calculated by the propagation loss calculation unit; a function setting unit that multiplies the objective function calculated by the objective function calculation unit by the first coefficient, and multiplies a predetermined scattering constraint condition by the second coefficient and adds the result to a function, and sets the function to a calculation device; a propagation path specifying unit that obtains a result of minimizing the function set by the function setting unit by the arithmetic device and specifies a propagation path from the transmission point to the reception point; An information processing program for causing a computer to function as each part of the information processing device having the above-mentioned components.

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