Relay station simulation system, relay station simulation efficiency improvement device, relay station simulation method, and relay station simulation efficiency improvement program

Abstract

Provided is a system that increases the efficiency of a simulation of the radio wave propagation characteristics of a relay station. A simulation result storage unit 30 stores a calculated parameter and a calculation result of a simulation based on the calculated parameter. Upon reception of a simulation parameter including information regarding the arrangement of a transmitter, a receiver, and a relay station, a simulation efficiency increasing device 20 determines whether or not the simulation result storage unit 30 stores a calculated parameter that can be diverted. If a calculated parameter that can be diverted is found, the calculation result based on the calculated parameter is output as a calculation result for the simulation parameter. Only in cases when a calculated parameter that can be diverted is not found, the simulation parameter is provided to a simulator 40 and a calculation result obtained by the simulator 40 is output as a calculation result for the simulation parameter.

Description

[Technical Field]

[0001] This disclosure relates to a relay station simulation system, a relay station simulation efficiency improvement device, a relay station simulation method, and a relay station simulation efficiency improvement program, and in particular to a relay station simulation system, a relay station simulation efficiency improvement device, a relay station simulation method, and a relay station simulation efficiency improvement program that are suitable for improving the efficiency of simulations related to the radio wave propagation characteristics of relay stations that reflect wireless signals. [Background technology]

[0002] In the field of wireless communications, relay stations are often placed between wireless base stations and terminal devices. Using relay stations, for example, in environments where a direct path from a wireless base station to a terminal device is blocked by obstacles, a path can be established between the two via reflection. Therefore, using relay stations can reduce dead spots within the service area.

[0003] One type of relay station is the Reconfigurable Intelligent Surface (RIS), which has multiple elements arranged in a grid pattern, and by electrically changing the characteristics of each element, it is possible to dynamically change the reflection characteristics of electromagnetic waves.

[0004] When providing wireless communication services, it is sometimes necessary to analyze by simulation what kind of radio wave environment will be created in the service area with respect to the placement of wireless base stations and relay stations. When a RIS is used as a relay station, reflections at the RIS occur in directions other than the direction of regular reflection.

[0005] Non-Patent Document 1 below proposes a method of using an existing 3D radio wave propagation simulator and a 3D electromagnetic field simulator to perform electromagnetic field analysis of the amount of absorption in all directions other than the regular reflection direction, and taking into account paths other than the regular reflection direction using the ray tracing method. For example, the simulation method proposed here makes it possible to simulate and calculate the radio wave propagation characteristics occurring in the service area for a system that uses a RIS as a relay station. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Verification of pyramidal absorbers, Structural Planning Institute website, July 6, 2021 https: / / network2.kke.co.jp / consulting_samples / anechoic_chamber / Summary of the Invention [Problem to be solved by the invention]

[0007] In conventional analysis methods, a simulation of radio wave propagation characteristics is performed after specifying parameters such as the RIS control pattern, installation location, number of units, etc. If parameters such as the control pattern change, a new simulation is performed based on the changed parameters.

[0008] However, simulations for each individual setting take a certain amount of time, and therefore, with conventional analysis methods, when the RIS control pattern changes dynamically, a significant amount of time is required to complete a series of simulations.

[0009] The present disclosure has been made in consideration of the above-mentioned problems, and has as its first object to provide a relay station simulation system that can efficiently obtain desired results when parameters related to the relay station of a wireless signal change.

[0010] A second object of the present disclosure is to provide a relay station simulation efficiency improvement device for efficiently obtaining desired results when parameters related to the relay station of a wireless signal change.

[0011] A third object of the present disclosure is to provide a relay station simulation method for efficiently obtaining desired results when parameters related to the relay station of a wireless signal change.

[0012] A fourth object of the present disclosure is to provide a relay station simulation efficiency improvement program for efficiently obtaining desired results when parameters related to a relay station of a wireless signal change. [Means for solving the problem]

[0013] In order to achieve the above object, a first aspect is a relay station simulation system that calculates, by simulation, radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, the system comprising: a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a simulator that executes a simulation of the radio wave characteristics based on parameters including information related to the locations of the transmitter, the receiver, and the relay station; a simulation efficiency improvement device capable of communicating with both the simulation result storage unit and the simulator, The simulation efficiency improvement device includes: receiving simulation parameters including information related to the placement; a reuse determination process for determining whether or not calculated parameters that can be reused as the simulation parameters are stored in the simulation result storage unit; a result output process for reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to the simulator as the parameters and outputting the calculation results by the simulator as the calculation results for the simulation parameters when the existence of the divertable calculated parameters is not recognized; Preferably, the system is configured to execute the following:

[0014] A second aspect is a relay station simulation efficiency improvement device that improves the efficiency of a simulation related to radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, the device comprising: receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; a process of determining whether or not a calculated parameter that can be used as the simulation parameter is stored in a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a process of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to a simulator and outputting a calculation result by the simulator as a calculation result for the simulation parameters when it is not recognized that there are any already-calculated parameters that can be reused; Preferably, the system is configured to execute the following:

[0015] A third aspect is a relay station simulation method for calculating, by simulation, radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, the method comprising: storing the calculated parameters and the calculation results of the simulation based on the calculated parameters in a simulation result storage unit; receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; determining whether or not calculated parameters that can be used as the simulation parameters are stored in the simulation result storage unit; a step of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; providing the simulation parameters to a simulator when it is determined that there are no reusable calculated parameters, and outputting a calculation result by the simulator as a calculation result for the simulation parameters; It is desirable to include:

[0016] A fourth aspect is a relay station simulation efficiency improvement program to be executed by a relay station simulation efficiency improvement device in order to improve the efficiency of a simulation relating to radio wave characteristics of a relay station that reflects a wireless signal from a transmitter toward a receiver, the program comprising: a processor unit provided in the relay station simulation efficiency improvement device, receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; a process of determining whether or not a calculated parameter that can be used as the simulation parameter is stored in a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a process of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to a simulator and outputting a calculation result by the simulator as a calculation result for the simulation parameters when it is not recognized that there are any already-calculated parameters that can be reused; It is preferable that the program include a program that executes the above. [Effects of the Invention]

[0017] According to the first to fourth aspects, when parameters related to the relay station of the wireless signal change, it is possible to efficiently perform simulations related to the radio wave characteristics of the relay station so that desired results can be obtained efficiently. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a diagram for explaining a target of a simulation executed in the first embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram illustrating an overview of a relay station simulation system according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a functional block diagram of the relay station simulation system shown in FIG. [Figure 4] 2 is a flowchart illustrating a flow of processing executed by the simulation efficiency improvement device shown in FIG. 1. [Figure 5] 2 is a diagram for explaining an overview of a first embodiment of a method for improving the efficiency of a simulation using the relay station simulation system shown in FIG. 1. FIG. [Figure 6] FIG. 2 is a diagram for explaining features of a first embodiment of a method for improving the efficiency of a simulation. [Figure 7] 1. FIG. 4 is a diagram for explaining an overview of a second embodiment of a method for improving the efficiency of a simulation using the relay station simulation system shown in FIG. [Figure 8] FIG. 10 is a diagram for explaining features of a second embodiment of a method for improving the efficiency of a simulation. [Figure 9]1. FIG. 4 is a diagram for explaining an overview of a third embodiment of a method for improving the efficiency of a simulation using the relay station simulation system shown in FIG. [Figure 10] FIG. 10 is a diagram for explaining features of a third embodiment of a method for improving the efficiency of a simulation. DETAILED DESCRIPTION OF THE INVENTION

[0019] Embodiment 1 [Background of the first embodiment] Fig. 1 shows an example of a service area 10 assumed as a target of a simulation in the first embodiment of the present disclosure. In Fig. 1, a wireless base station 12 is located in the upper left of the service area 10. A RIS 14 functioning as a relay station is located in the center right of the service area. The RIS 14 is a reflector that includes multiple elements arranged in a lattice pattern and can dynamically change the reflection characteristics of electromagnetic waves by electrically changing the characteristics of each element.

[0020] In the service area 10, an obstacle wall 16 is installed that blocks wireless signals from traveling in a straight line. Fig. 1 shows a situation in which a terminal device 18 is located in a dead space where signals from a wireless base station 12 cannot reach directly due to the influence of the obstacle wall 16. Even in such an environment, if the RIS 14 appropriately reflects the wireless signal from the wireless base station 12 toward the terminal device 18, a path can be formed between the wireless base station 12 and the terminal device 18, and good communication quality can be obtained.

[0021] In order to provide good wireless quality throughout the entire service area 10, it is necessary to investigate how wireless signals from the wireless base station 12 propagate within the service area 10. The radio wave propagation characteristics within the service area 10 vary depending on the control pattern, installation location, number of RISs 14, etc. Therefore, in order to create an optimal environment using the RIS 14, it is necessary to investigate the radio wave propagation characteristics under various conditions by changing the control pattern, installation location, etc.

[0022] The relay station simulation system of this embodiment is used to calculate the above-mentioned radio wave propagation characteristics instead of conducting an actual survey. More specifically, the system of this embodiment is used to simulate the radio wave intensity at each location within the service area 10 using parameters such as the control pattern, installation location and number of RISs 14, and installation location of the radio base station 12.

[0023] [Configuration of the First Embodiment] FIG. 2 is a diagram illustrating an overview of a relay station simulation system according to a first embodiment of the present disclosure. The system according to this embodiment includes a simulation efficiency improvement device 20. The simulation efficiency improvement device 20 incorporates a processor unit and a memory device, not shown. The memory device stores a simulation efficiency improvement program executed by the processor unit. The functions of the simulation efficiency improvement device 20 are realized by the processor unit executing the program.

[0024] The simulation efficiency improving device 20 also includes an input interface and an output interface (not shown). Simulation parameters set by an operator are provided to the simulation efficiency improving device 20 via the input interface. The simulation parameters include the following information: The location of the wireless base station 12 in the service area 10 Number of RIS14s deployed in Service Area 10 -Installation location of each RIS14 Control patterns applied to each RIS14

[0025] The simulation efficiency improvement device 20 can read and write data by accessing the simulation result storage unit 30. The simulation result storage unit 30 is a database for storing simulation results related to radio wave propagation characteristics and simulation parameters (hereinafter referred to as "calculated parameters") used when the results were obtained.

[0026] When the simulation efficiency improving device 20 receives a new simulation parameter, it first accesses the simulation result storage unit 30 to check whether there is an already-calculated parameter that can be equated with the new simulation parameter. If an already-calculated parameter that can be equated with the new simulation parameter is found, the simulation result corresponding to the already-calculated parameter is read out and the result is output as the calculation result corresponding to the new simulation parameter.

[0027] On the other hand, if no calculated parameters that can be equated with the new simulation parameters are found, the new simulation parameters are provided to simulator 40. Simulator 40 has the function of calculating the radio wave propagation characteristics of the reflected waves from the RIS by performing electromagnetic field analysis based on the path and incident angle of the radio signal analyzed using the ray tracing method. Simulator 40 can be implemented, for example, using the 3D radio wave propagation simulator RapLab and the 3D electromagnetic field simulator XFdtd provided by Structural Planning Engineering Co., Ltd.

[0028] As described above, the simulation efficiency improving device 20 provides new simulation parameters to the simulator 40 only when there are no calculated parameters that can be identified with the new simulation parameters. Therefore, the simulator 40 executes a simulation only when existing calculation results cannot be reused.

[0029] The results of the simulation by the simulator 40 are provided as calculation results to the simulation efficiency improvement device 20. When the simulation efficiency improvement device 20 receives the calculation results from the simulator 40 in this way, it writes the calculation results together with the simulation parameters on which the current simulation was based in the simulation result storage unit 30. Furthermore, it outputs the calculation results received from the simulator 40 as calculation results corresponding to the new simulation parameters.

[0030] Fig. 3 is a functional block diagram showing the configuration of the relay station simulation system shown in Fig. 1, broken down functionally. In Fig. 3, functions of the simulation efficiency improvement device 20 are represented by reference characters formed by adding a suffix "-n" to the symbol "20." The simulator 40 and the simulation result storage unit 30 are given the same reference characters as in Fig. 1.

[0031] 3, a simulation parameter reading unit 20-1 is an input interface of the simulation efficiency improving device 20. Various parameters set by an operator are taken in by the simulation parameter reading unit 20-1.

[0032] The calculation result reuse determination unit 20-2 determines whether or not calculated parameters that can be identified with the newly read simulation parameters are stored in the simulation result storage unit 30. If the result indicates that there are no calculated parameters that can be reused, new simulation parameters are set in the simulator 40 by the simulation parameter setting unit 20-3.

[0033] On the other hand, if the calculation result diversion determining unit 20-2 recognizes the existence of diversionable calculated parameters, it issues a command to the simulation result rewriting unit 20-4 to rewrite the simulation results as necessary.

[0034] The simulation result storage unit 30 may store simulation results of simple specular reflection analyzed by the ray tracing method in combination with calculated parameters that are determined to be reusable. When a RIS is used as a relay station, the simulation results of specular reflection must be replaced with simulation results based on electromagnetic field analysis. In such a case, the simulation result rewriting unit 20-4 rewrites the data stored in the simulation result storage unit 30 from the results of specular reflection to the results of electromagnetic field analysis.

[0035] The simulation result output unit 20-5 is an output interface of the simulation efficiency improvement device 20. The simulation results returned from the simulator 40 to the simulation efficiency improvement device 20 and the simulation results read out from the simulation result storage unit 30 as reusable results are output from the simulation result output unit 20-5 to, for example, an operator.

[0036] [Processing flow in the first embodiment] 4 is a flowchart for explaining the flow of processing that proceeds as a result of the processor unit of the simulation efficiency improvement device 20 executing the simulation efficiency improvement program. The routine shown in FIG. 4 is started when new simulation parameters are provided to the simulation efficiency improvement device 20.

[0037] First, newly provided simulation parameters are read in (step 100).

[0038] Next, it is determined whether or not there are any reusable calculated parameters (step 102). The conditions for determining whether or not a parameter is "reusable" will be explained in detail later with reference to the first to third embodiments.

[0039] If it is determined in the above process that there are no reusable calculated parameters, new simulation parameters are set in the simulator 40 (step 104).

[0040] Next, execution of the simulation is instructed to the simulator 40. After that, when the simulator 40 finishes the simulation, the results of the execution are taken into the simulation efficiency improvement device 20 (step 106).

[0041] On the other hand, if it is determined in step 102 that there are any divertable calculated parameters, the existing simulation results corresponding to those calculated parameters are read from the simulation result storage unit 30 (step 108).

[0042] Next, if necessary, the read-in existing simulation results are rewritten (step 110). Specifically, if the read-in results are the results of regular reflection by the ray tracing method, the results are rewritten as the results of electromagnetic field analysis. However, if the read-in results are the results of electromagnetic field analysis, it is determined that rewriting is not necessary, and the rewriting process is skipped.

[0043] When the above processing is completed, the simulation parameters processed in this routine and the simulation results corresponding to those parameters are stored in the simulation result storage unit 30. In addition, the simulation results obtained in this routine are output, for example, to an operator (step 112).

[0044] As described above, the relay station simulation system of this embodiment can effectively utilize existing calculation results. Therefore, according to the system of this embodiment, when parameters related to the RIS 14 change, desired calculation results can be efficiently obtained, and the simulation can be completed with high efficiency.

[0045] (First Example) Hereinafter, a first example of a method for improving the efficiency of a simulation using the relay station simulation system of this embodiment will be described with reference to FIGS. FIG. 5 is a diagram for explaining an outline of the first embodiment, and more specifically, a diagram for explaining elements that the first embodiment focuses on to improve the efficiency of simulation.

[0046] When performing a simulation for the service area 10, first, the physical configuration of the service area 10 is determined. Specifically, the locations of the wireless base station 12 functioning as a transmitter, the RIS 14 functioning as a relay station, and the terminal device 18 functioning as a receiver are determined (step 120).

[0047] Next, the path from the transmitter to the receiver via the relay station is analyzed using a ray tracing method (step 122). Furthermore, for each path obtained by the analysis, the angle at which the wireless signal enters the relay station is identified as the angle of incidence to be analyzed (step 124). Once these identifications are complete, it becomes possible to perform a simulation using electromagnetic field analysis.

[0048] If the "analysis result (path)" shown in Fig. 5 is the same, the "incident angle to be analyzed" and the simulation result by "electromagnetic field analysis" will also be the same. Therefore, in the first embodiment, the calculation result reuse determination unit 20-2 shown in Fig. 3 determines whether the calculated parameters are "reusable" or not based on the identity of the "analysis result (path)" by the processing of step 102 shown in Fig. 4.

[0049] Fig. 6 is a diagram for explaining the features of the first embodiment described above. The upper left column of Fig. 6 shows the layout of a service area 10 indicated by one of the calculated parameters. Three RISs 14-1 to 14-3 are arranged between a wireless base station 12 functioning as a transmitter and a terminal device 18 functioning as a receiver.

[0050] The layout of the analysis target indicated by the new simulation parameters is shown in the upper right column of Fig. 6. Here, two RISs 14-1 and 14-3 are placed between the radio base station 12 and the terminal device 18. Their positions are the same as those corresponding to the calculated parameters.

[0051] As described above, in the method of the first embodiment, the applicability of a path is determined based on the identity of the path. In the analysis target shown in Figure 6, it can be assumed that the path via RIS14-1 and the path via RIS14-3 are the same as the paths via those paths in the calculated layout. Therefore, in this case, by deleting the results related to the path via RIS14-2, which does not exist in the analysis target, from the simulation results stored in combination with the calculated parameters, it is possible to obtain results that can be reused as simulation results for new simulation parameters (see the lower right column in Figure 6).

[0052] As described above, in the first example of efficiency improvement, whether or not calculated parameters can be reused is determined based on the identity of the paths. Then, the relay station simulation system of this embodiment can improve the efficiency of the simulation by using the method of the first example if the positions of the radio base station 12, terminal device 18, and RIS 14 included in the analysis target are the same as those in the calculated layout.

[0053] (Second Example) Next, a second example of a method for improving the efficiency of a simulation using the relay station simulation system of this embodiment will be described with reference to FIGS. Fig. 7 is a diagram for explaining an overview of the second embodiment, more specifically, a diagram for explaining elements that the second embodiment focuses on to improve the efficiency of simulation. In Fig. 7, elements that are the same as those shown in Fig. 5 are assigned the same reference numerals, and duplicate explanations are omitted or simplified.

[0054] The RIS 14 changes the reflection direction of the radio waves depending on the control angle, so a simulation of the radio wave propagation characteristics for the service area 10 including the RIS 14 must be performed for each control angle of the RIS 14 (step 126).

[0055] The direction in which the radio waves are reflected by the RIS 14 is determined by electrically changing the characteristics of each of the multiple elements arranged in a lattice pattern on the RIS 14. In other words, once the control angle of the RIS 14 is determined, the pattern of characteristics to be given to each element to achieve that control angle, i.e., the RIS pattern, can be determined by numerical calculation (step 128).

[0056] Simulations using electromagnetic field analysis may be performed to analyze the reflection characteristics of the RIS 14 for various angles of incidence under a specific RIS pattern α (step 130).

[0057] Here, the reflection characteristics under the RIS pattern α are the same if the angle of incidence is the same. Therefore, in the second embodiment, the calculation result reuse determination unit 20-2 shown in Fig. 3 determines whether the calculated parameters are "reusable" based on the identity of the "angle of incidence" with respect to the RIS 14, by the processing of step 102 shown in Fig. 4.

[0058] Fig. 8 is a diagram for explaining the features of the second embodiment described above. The left column of Fig. 8 shows that for a specific RIS pattern α, the "reflection characteristics" for "incident angles" of 30 degrees and 45 degrees have been calculated as X and Y, respectively.

[0059] On the other hand, the right column of Fig. 8 shows that the new simulation parameters are used to analyze the following angles of incidence. 15 degrees (uncalculated) 30 degrees (with calculation results for reflection characteristics X) 45 degrees (with calculation results for reflection characteristic Y) 60 degrees (uncalculated)

[0060] As described above, in the method of the second embodiment, whether or not to reuse a result is determined based on the identity of the incident angle. For the analysis target shown in Figure 8, the same incident angles as those of 30 degrees and 45 degrees are included in the calculated parameters. Therefore, in the method of the second embodiment, the existing results X and Y are reused for the analysis target of 30 degrees and 45 degrees, and a new simulation is performed only for the analysis target of 15 degrees and 60 degrees, for which no results to reuse exist.

[0061] As described above, in the second example of efficiency improvement, whether or not calculated parameters can be reused is determined based on the identity of the incident angle with respect to the RIS 14. Then, if the incident angle included in the analysis target is the same as the calculated incident angle, the relay station simulation system of this embodiment can improve the efficiency of the simulation by using the method of the second example.

[0062] In the second embodiment described above, the simulation results for the RIS pattern α at angles of incidence of 30 degrees and 45 degrees are used. However, the present disclosure is not limited to this. If the reflection characteristics Xn and Yn at angles of incidence of 30 degrees and 45 degrees have been calculated for all of the configurable RIS patterns n (n = 1 to N), the results Xn and Yn for angles of incidence of 30 degrees and 45 degrees may be treated as applicable for all RIS patterns, not just the RIS pattern α.

[0063] (Third Example) Next, a third example of a method for improving the efficiency of a simulation using the relay station simulation system of this embodiment will be described with reference to FIGS. Fig. 9 is a diagram for explaining an overview of the third embodiment, more specifically, a diagram for explaining elements that the third embodiment focuses on to improve the efficiency of simulation. In Fig. 9, elements that are the same as those shown in Fig. 5 or 7 are given the same reference numerals, and duplicate explanations are omitted or simplified.

[0064] As explained in the second embodiment, a simulation of the service area 10 including the RIS 14 is performed by determining the control angle of the RIS 14 (step 126). Then, a RIS pattern α that realizes the control angle of the RIS 14 is determined (step 128), and the reflection characteristics for each incident angle are calculated by simulation (step 130).

[0065] In the process of step 126, the control angle of the RIS 14 is determined so that the signal reflected by the RIS 14 travels toward a terminal device 18 located at a specific location within the service area 10. Meanwhile, the direction of signal reflection by the RIS 14 changes stepwise as the RIS pattern changes. Therefore, if the difference between the two control angles is small, the corresponding RIS patterns may be identical.

[0066] Here, even if the control angles are different, if the RIS pattern is the same, the simulation results for those control angles will be the same. For this reason, in the third embodiment, the calculation result reuse determination unit 20-2 shown in Fig. 3 determines whether the calculated parameters are "reusable" based on the identity of the "RIS pattern" through the processing of step 102 shown in Fig. 4.

[0067] FIG. 10 is a diagram illustrating the features of the third embodiment described above. The left column of FIG. 10 shows that calculations have been performed for the cases where the "control angle" of the RIS 14 is 30 degrees and 45 degrees. Here, it is assumed that the RIS 14 has nine elements arranged in a 3×3 grid. The 3×3 "1" or "0" shown in the RIS pattern column for the control angle "30 degrees" represents the state of each of the nine elements arranged in the grid. For example, "1" represents a phase change state, and "0" represents an unchangeable phase state.

[0068] In other words, the left column of Figure 10 represents the following events: (1) The control angles of 30 degrees and 45 degrees have been calculated. (2) The 30-degree RIS pattern and the 45-degree RIS pattern are different. (3) The 30-degree reflectance characteristic list is α, and the 45-degree reflectance characteristic list is β.

[0069] The right side of Figure 10 shows that the new simulation parameters are the following control angles to be analyzed. 30 degrees (RIS pattern is |110| x 3, calculation results for reflection characteristic list α available) 32 degrees (RIS pattern is the same as for 30 degrees, so the reflection characteristic list α can be reused) 45 degrees (RIS pattern is |101| x 3, reflection characteristic list β calculation results available) 60 degrees (RIS pattern is |010| x 3, reflection characteristic list is not calculated)

[0070] As described above, the method of the third embodiment determines whether or not a RIS pattern can be reused based on the identity of the RIS pattern. In the analysis target shown in Figure 10, the RIS pattern for the 32-degree angle is identical to the calculated RIS pattern for the 30-degree angle. Therefore, in the method of the third embodiment, the calculated α and β results are reused for the 30-degree and 45-degree angles, and the existing α is also reused as the result for the uncalculated 32-degree angle. Then, a new simulation is performed only for the 60-degree angle, which has not yet been calculated and does not contain the same RIS pattern as the calculated pattern.

[0071] As described above, in the third embodiment of the efficiency improvement, whether or not calculated parameters can be reused is determined based on the identity of the RIS pattern. Then, if the RIS pattern included in the analysis target is the same as the calculated RIS pattern, the relay station simulation system of this embodiment can improve the efficiency of the simulation by using the method of the third embodiment.

[0072] [Modification of the first embodiment] Incidentally, in the above-described first embodiment, a case where the relay station is a RIS is described, but the present disclosure is not limited to this. The relay station may be any station that has the function of relaying a wireless signal, and may be, for example, a general repeater. Even when a simulation is required for a service area using a general repeater, it is possible to omit the simulation for parameters for which the results can be reused and utilize existing results. [Explanation of symbols]

[0073] 10 Service Area 12 Wireless base stations 14 RIS(Reconfigurable Intelligent Surface) 16 Obstacle Wall 18 Terminal Equipment 20 Simulation efficiency improvement device 30 Simulation result storage unit 40 Simulator

Claims

1. A relay station simulation system that calculates, by simulation, radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, comprising: a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a simulator that executes a simulation of the radio wave characteristics based on parameters including information related to the locations of the transmitter, the receiver, and the relay station; a simulation efficiency improvement device capable of communicating with both the simulation result storage unit and the simulator, The simulation efficiency improvement device includes: receiving simulation parameters including information related to the placement; a reuse determination process for determining whether or not calculated parameters that can be reused as the simulation parameters are stored in the simulation result storage unit; a result output process for reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to the simulator as the parameters and outputting the calculation results by the simulator as the calculation results for the simulation parameters when the existence of the divertable calculated parameters is not recognized; a relay station simulation system configured to execute the above steps.

2. 2. The relay station simulation system according to claim 1, wherein the diversion determination process includes a process of determining whether the diversion is possible based on the identity between the wireless signal path indicated by the simulation parameters and the wireless signal path indicated by the calculated parameters.

3. 2. The relay station simulation system according to claim 1, wherein the diversion determination process includes a process for determining whether the diversion is possible based on the identity of an incident angle of the wireless signal to the relay station indicated by the simulation parameters and an incident angle of the wireless signal to the relay station indicated by the calculated parameters.

4. the relay station is a RIS; The RIS is configured to reflect the radio signal in a direction according to a set RIS pattern, The relay station simulation system according to claim 1, wherein the diversion determination process includes a process of determining whether the diversion is possible based on the identity between the RIS pattern indicated by the simulation parameters and the RIS pattern indicated by the calculated parameters.

5. the relay station is a RIS; 5. The relay station simulation system according to claim 1, wherein the result output process includes a process of rewriting the calculation result read from the simulation result storage unit into the result of an electromagnetic field analysis targeting the RIS when the calculation result read from the simulation result storage unit is a result of regular reflection corresponding to a ray tracing method.

6. A relay station simulation efficiency improvement device for improving the efficiency of a simulation of radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, comprising: receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; a process of determining whether or not a calculated parameter that can be used as the simulation parameter is stored in a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a process of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to a simulator and outputting a calculation result by the simulator as a calculation result for the simulation parameters when it is not recognized that there are any already-calculated parameters that can be reused; A relay station simulation efficiency device configured to execute the above.

7. A relay station simulation method for calculating, by simulation, radio wave characteristics of a relay station that reflects a radio signal from a transmitter toward a receiver, comprising: storing the calculated parameters and the calculation results of the simulation based on the calculated parameters in a simulation result storage unit; receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; determining whether or not calculated parameters that can be used as the simulation parameters are stored in the simulation result storage unit; a step of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; providing the simulation parameters to a simulator when it is determined that there are no reusable calculated parameters, and outputting a calculation result by the simulator as a calculation result for the simulation parameters; A relay station simulation method including:

8. A relay station simulation efficiency improvement program that is executed by a relay station simulation efficiency improvement device to improve the efficiency of a simulation relating to radio wave characteristics of a relay station that reflects a wireless signal from a transmitter toward a receiver, the program comprising: a processor unit provided in the relay station simulation efficiency improvement device, receiving simulation parameters including information regarding the location of the transmitter, the receiver, and the relay station; a process of determining whether or not a calculated parameter that can be used as the simulation parameter is stored in a simulation result storage unit that stores calculated parameters and calculation results of a simulation based on the calculated parameters; a process of reading out the calculation results based on the calculated parameters from the simulation result storage unit and outputting the results as calculation results for the simulation parameters when the existence of the calculated parameters that can be reused is recognized; a process of providing the simulation parameters to a simulator and outputting a calculation result by the simulator as a calculation result for the simulation parameters when it is not recognized that there are any already-calculated parameters that can be reused; A relay station simulation efficiency improvement program including a program for executing the above.

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