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

Abstract

To efficiently search for a propagation path contributing to propagation of radio waves even when the radio waves are scattered.SOLUTION: A propagation path search system includes: a propagation loss calculation unit that calculates a propagation loss of radio waves between a transmission point, a reception point, and each of a plurality of structures, based on the predetermined number of scattering times for each structure; an objective function calculation unit that calculates, based on the propagation loss calculated by the propagation loss calculation unit, an objective function that is a propagation loss on a propagation path from the transmission point to the reception point; a function setting unit that sets, to an arithmetic device, a function which is obtained by adding a predetermined constraint of scattering to the objective function calculated by the objective function calculation unit; and a propagation path specification unit that obtains a result of minimization by the arithmetic device of the function which is set by the function setting unit, and specifies a propagation path from the transmission point to the reception point. The propagation loss calculation unit sets the center of gravity of each structure as a scattering point for the structure.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 a 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]

number

[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, structures such as buildings have multiple surfaces that generate scattering. For example, when extracting the scattering surfaces of a structure from a map database, it is necessary to decompose the building into multiple surfaces and set quantum bits for the paths scattered by each scattering surface and perform a search.

[0014] In other words, in this case, the scattering paths between surfaces within the same building are also taken into account, which poses the problem that the number of quantum bits becomes enormous, making it difficult to implement on a quantum computer with a small number of quantum bits.

[0015] Specifically, in a scattering model having a directional pattern shown in Fig. 1, the scattering of radio waves depends on the angle of incidence and the angle of scattering. Fig. 1 shows a scattering model based on a single lobe (ER) type propagation model on a flat plate.

[0016] 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).

[0017]

number

[0018] 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).

[0019]

number

[0020] In other words, as the number of scattering surfaces increases, a large number of quantum bits must be used, and complex models are needed to calculate the propagation characteristics of radio waves, resulting in a huge amount of calculations.

[0021] 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 a program that are capable of efficiently searching for propagation paths that contribute to the propagation of radio waves even when the radio waves are scattered. [Means for solving the problem]

[0022] 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 having the following features: a propagation loss 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 predetermined number of scattering times for each of the structures; an objective function calculation unit that calculates an objective function that 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 sets each of functions obtained by adding a predetermined scattering constraint condition to the objective function calculated by the objective function calculation unit; 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, and the propagation loss calculation unit sets the center of gravity of the structure as the scattering point for each of the structures.

[0023] 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 having the following features: a propagation loss 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 predetermined number of scatterings for each of the structures; an objective function calculation unit that calculates an objective function that 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 sets, in a calculation device, each of functions obtained by adding a predetermined scattering constraint condition to the objective function calculated by the objective function calculation unit; and a propagation path identification unit that acquires a result obtained by 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, and is characterized in that the propagation loss calculation unit sets the center of gravity of the structure as the scattering point for each of the structures.

[0024] Moreover, a propagation path searching method according to one embodiment of the present invention is 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 transmission point and scattered by a plurality of structures before reaching a reception point, the propagation path searching method being characterized in that the information processing device performs the following steps: a propagation loss calculation step of calculating a propagation loss of the radio wave between the transmission point, the reception point, and each of the structures based on a predetermined number of scatterings for each of the structures; an objective function calculation step of calculating an objective function that 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 setting, in the arithmetic device, each of functions obtained by adding a predetermined scattering constraint condition to the objective function calculated in the objective function calculation step; and a propagation path identification step of acquiring a result in which the arithmetic device minimizes the function set in the function setting step and identifying the propagation path from the transmission point to the reception point, and in the propagation loss calculation step, the center of gravity of the structure is set as the scattering point for each of the structures. Effect of the Invention

[0025] According to the present invention, even when radio waves are scattered, it is possible to efficiently search for a propagation path that contributes 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] FIG. 2 is a diagram showing a schematic diagram of structures and surfaces (scattering surfaces) that each of the structures has. [Figure 6] 4A to 4C are diagrams illustrating examples of setting a scattering surface in the present embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of settings for calculating propagation loss between structures. [Figure 8] 1A and 1B are diagrams illustrating an example of scattering used by the propagation path searching system when radio waves penetrate a structure. [Figure 9] FIG. 13 is a diagram illustrating the definition of QUBO variables of the propagation path discovery system. [Figure 10] 1 is a diagram illustrating an example of a propagation path from a transmitting point to a receiving point and a QUBO transformation matrix. [Figure 11] 4 is a flowchart illustrating an example of the operation of the propagation path searching system according to an embodiment. 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]

number

[0030]

number

[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 existing in an 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. The acquisition unit 400 also acquires information such as setting items required for calculating the propagation loss, and outputs the information to the function setting unit 406.

[0045] 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.

[0046] Furthermore, the propagation loss calculation unit 402 sets, for example, the center of gravity of a structure as the scattering point for each structure. Furthermore, when calculating, for example, the propagation loss between structures, the propagation loss calculation unit 402 sets the propagation path based on the incident surface to the structure.

[0047] Fig. 5 is a diagram showing a structure 2 and the surfaces (scattering surfaces) of each of the structures 2. As shown in Fig. 5, each of the structures 2 has, for example, four surfaces (scattering surfaces). If each of the structures 2 is decomposed into surfaces and a quantum bit is set for each, the scattering paths between the surfaces within the same structure 2 are also taken into consideration. This may result in an enormous number of quantum bits.

[0048] 6 is a diagram showing a schematic example of setting a scattering surface in this embodiment. In an actual scattering phenomenon, scattered waves do not enter or exit between surfaces within the same structure 2. Therefore, the propagation path searching system 10 does not take surfaces into consideration in the quantum bit for path searching, and sets the quantum bit at the center of gravity of the structure 2. For example, when calculating the center of gravity of a building, the propagation path searching system 10 divides the position vector of each vertex of the structure 2 by the number of vertices.

[0049] In this case, the propagation path searching system 10 can reduce the number of scattering surfaces to one per structure 2, and the number of required quantum bits can be significantly reduced.

[0050] 7 is a diagram showing a schematic setting example for calculating the propagation loss between structures 2 and 2. When calculating the propagation loss between structures 2 and 2, the propagation path searching system 10 may perform the calculation of equation (10) described later using the surface of the structure 2. In this case, the propagation path searching system 10 sets the path based on the incident surface of the radio wave, and the state of the surface of the structure 2 does not need to be used in the calculation.

[0051] Fig. 8 is a diagram showing a schematic example of scattering used by the propagation path searching system 10 when radio waves pass through the structure 2. As shown in Fig. 8, when radio waves pass through the structure 2, the propagation path searching system 10 sets a uniform transmission loss for the incident surface and allows the radio waves to pass through.

[0052] The objective function calculation unit 404 is configured in, for example, the information processing device 20, and calculates a second-order 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 identified by the propagation path identification unit 410 has already been identified, the objective function calculation unit 404 performs calculation based on the identified propagation path.

[0053] The function setting unit 406 is configured in, for example, the information processing device 20, and sets, for the minimization processing unit 408, functions each of which is obtained by adding a predetermined scattering constraint condition to the objective function calculated by the objective function calculation unit 404.

[0054] In addition, the function setting unit 406 includes in the scattering constraint conditions (described later) that the radio waves are always 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.

[0055] 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 .

[0056] 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).

[0057] 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.

[0058] 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.

[0059] 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).

[0060]

number

[0061] Here, L is an objective function that describes the physical quantity to be evaluated. 1 ,J 2 ,J 3 ,J 4 Each of A, B, C, and D indicates a constraint condition for channel search (described later). Also, A, B, C, and D are positive weighting coefficients that adjust the strength of each of the different constraint conditions.

[0062] 9 is a diagram illustrating the definition of the QUBO variables of the propagation path searching system 10. As described above, the propagation path searching system 10 uses the following expressions as variables to represent the propagation path, with the number of structures in the search area being M and the number of scatterings (number of reflections, etc.) being N. Here, the QUBO variables are q ik∈{1,0}: Binary variable, which is set to “1” when the kth plate of the structure is reached, and “0” otherwise.

[0063] 10 is a diagram illustrating an example of a propagation path from a transmission point Tx to a reception point Rx and a QUBO transformation matrix. Here, one of the objective functions (propagation loss) L of the propagation QUBO model is expressed by, for example, the following formula (7).

[0064]

number

[0065] In addition, if the objective function (propagation loss) L of the propagation QUBO model is the total loss, the objective function L is expressed, for example, by the following equation (8).

[0066]

number

[0067] In this case, the loss from the transmission point Tx to the structure i is expressed by the following formula (9), the loss from the structure j to the structure k of the radio wave incident from the structure i is expressed by the following formula (10), and the loss from the structure j to the receiving point Rx of the radio wave incident from the structure i is expressed by the following formula (11). Note that when i=0, the incident point is from the transmission point Tx.

[0068]

number

number

number

[0069] Note that the above equation (9) represents a propagation vector on the transmitting point Tx side, the above equation (10) represents a propagation loss matrix, and the above equation (11) represents a propagation vector on the receiving point Rx side.

[0070] In addition, the propagation path search system 10 determines the weighted constraints J 1 ,J 2 ,J 3 ,J 4 is added to the objective function L to calculate the function H.

[0071] Constraint J 1 It is assumed that "radio waves are always scattered N times, and each time there is only one plane for scattering," and is expressed by the following equation (12).

[0072]

number

[0073] In addition, constraint J 2 It is assumed that radio waves are not continuously scattered by the same flat plate, and is expressed by the following equation (13).

[0074]

number

[0075] In addition, constraint J 3 is expressed by the following equation (14), where the transmitting point Tx and the receiving point Rx are used only at the start and end points of the path, respectively.

[0076]

number

[0077] In addition, constraint J 4 is expressed by the following equation (15), assuming that radio waves do not travel back and forth between two structures.

[0078]

number

[0079] In addition, constraint J 4It may not be set in the directivity model.

[0080] Then, the propagation path search system 10 uses the objective function L shown in the above formula (8) after changing it from a cubic formula to the quadratic formula shown in the following formula (16).

[0081]

Equation

[0082] Next, an operation example of the propagation path search system 10 according to an embodiment will be described using a flowchart. FIG. 11 is a flowchart showing an operation example of the propagation path search system 10 according to an embodiment. As shown in FIG. 11, in the propagation path search system 10, an acquisition unit 400 acquires and refers to map data of a structure as preprocessing (S100).

[0083] Then, the propagation loss calculation unit 402 calculates each propagation loss based on the above formulas (9) to (11) according to the arrangement of each structure (S102).

[0084] Also, the propagation loss calculation unit 402 sets N and Np based on the information acquired by the acquisition unit 400 (S104), and sets Np = 0, J 3 = 0 as the initial value (S106), and calculates the propagation loss of each propagation path from the transmission point Tx to the reception point Rx. Note that n p is the number of searched propagation paths.

[0085] Next, the minimization processing unit 408 minimizes the function H (S108), stores the obtained value of q x,y as propagation path information (S110), and then updates the value of n p (S112).

[0086] Also, when n p < Np (S114: Yes), the process proceeds to the process of S116, and in other cases (S114: No), the process ends.

[0087] In the process of S116, the propagation path searching system 10 sets the constraint J 3 The value is updated, and the process returns to S108.

[0088] In this way, the propagation path searching system 10 performs quantum annealing (or simulated annealing) for searching each propagation path involving N scattering in order of smallest propagation loss.

[0089] In addition, since the propagation QUBO model does not have a term related to frequency, the propagation path searching system 10 performs a process of adding the value shown in the following equation (17).

[0090]

number

[0091] In this way, the propagation path searching system 10 according to one embodiment calculates objective functions that are propagation losses of the propagation paths from the transmitting point to the receiving point, sets functions by adding predetermined scattering constraint conditions to the objective functions, and performs minimization processing to minimize the functions. Therefore, even when radio waves are scattered, it is possible to accurately and quickly search for propagation paths that contribute to the propagation of radio waves.

[0092] 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.

[0093] Furthermore, the propagation path search 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. The propagation path search system 10 then simplifies the extraction of paths by considering the center of gravity of a structure such as a building as a virtual scattering point. At this time, it has been confirmed that the accuracy of the calculation results obtained is not significantly affected, and the amount of calculation (quantum bits) can be significantly reduced from a model that takes into account many surfaces. [Explanation of symbols]

[0094] 2 structure, 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: 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 functions by adding predetermined constraint conditions of scattering to the objective functions calculated by the objective function calculation unit; 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; having The propagation loss calculation unit is A propagation path searching system, characterized in that the center of gravity of the structure is set as the scattering point for each of the structures.

2. The propagation loss calculation unit is When calculating the propagation loss between the structures, a propagation path is set based on an incident surface of the structure.

2. The propagation path searching system according to claim 1,

3. 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, 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, in a calculation device, functions each obtained by adding a predetermined constraint condition of scattering to the objective function calculated by the objective function calculation unit; 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; having The propagation loss calculation unit is 4. The information processing device according to claim 1, wherein the center of gravity of the structure is set as a scattering point for each of the structures.

4. The propagation loss calculation unit is When calculating the propagation loss between the structures, a propagation path is set based on an incident surface of the structure.

4. The information processing apparatus according to claim 3,

5. 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, 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 setting, in the arithmetic device, functions each obtained by adding a predetermined constraint condition on scattering to the objective function calculated in the objective function calculation step; 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; Do the following: In the propagation loss calculation step, A propagation path searching method, characterized in that the center of gravity of the structure is set as a scattering point for each of the structures.

6. In the propagation loss calculation step, When calculating the propagation loss between the structures, a propagation path is set based on the incident surface of the structure.

6. The method for searching a propagation path according to claim 5, further comprising:

7. 5. A program for causing a computer to function as each of the units of the information processing device according to claim 3.

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