Propagation environment reproduction device, propagation environment reproduction method, and propagation environment reproduction system

Abstract

This disclosure relates to a propagation environment reproduction device that reproduces a propagation environment for verifying the communication performance and the like of an object of measurement. The device comprises: an electromagnetic anechoic chamber 10 that blocks electromagnetic waves from the outside; reconfigurable intelligent surfaces (RISs) 16 installed in the electromagnetic anechoic chamber 10; an RIS control device 22 that provides control signals to the RISs 16; transmitting antennas 20 installed in the electromagnetic anechoic chamber 10; a channel emulator 24 that controls the characteristics of electromagnetic waves transmitted from the transmitting antennas 20; and a control server 26 that controls the RIS control device 22 and the channel emulator 24. The RISs 16 are reflective plates having the characteristic of changing the reflection pattern in response to the control signals.

Description

[Technical Field]

[0001] The present disclosure relates to a propagation environment reproducing device, a propagation environment reproducing method, and a propagation environment reproducing system, and in particular to a propagation environment reproducing device, a propagation environment reproducing method, and a propagation environment reproducing system that are suitable for reproducing a propagation environment for verifying the communication performance, etc., of an object to be measured. [Background technology]

[0002] Non-Patent Document 1 below discloses technology related to OTA (Over The Air) testing, which verifies the performance and quality of devices used in wireless communication as the test object. In OTA testing, one or more transmitting antennas are placed in an anechoic chamber or a shielded room, and an environment exhibiting the same propagation characteristics as in the real space is reproduced within that space.

[0003] By measuring the communication quality of the object in a propagation environment that replicates the propagation characteristics that occur in real space, it is possible to measure the communication quality that is demonstrated in real space. Therefore, by using the OTA method, it is possible to easily and accurately evaluate the performance of devices used for wireless communication. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] “MIMO OTA Test for a Mobile Station Performance Evaluation”, Ya Jing, Hongwei Kong, and Moray Rumney, IEEE Instrumentation & Measurement Magazine, p43-p50, June 2016 Summary of the Invention [Problem to be solved by the invention]

[0005] The biggest challenge in conducting OTA testing is how to accurately reproduce the desired radio propagation environment that occurs in real space.On the other hand, a reflector called a Reconfigurable Intelligent Surface (RIS) is known as a device that controls the reflection of radio waves.

[0006] RIS is a tunable reflector that uses metamaterial technology, which means that the properties of a material can be artificially changed. For example, this technology can create a phenomenon in which the refractive index of electromagnetic waves becomes negative.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and has as its first object to provide a propagation environment reproducing device that accurately reproduces a desired wireless propagation environment by placing a RIS in a space such as an anechoic chamber and simultaneously controlling the reflection direction and reflection intensity of electromagnetic waves by the RIS.

[0008] A second object of the present disclosure is to provide a propagation environment reproduction method for accurately reproducing a desired wireless propagation environment by placing a RIS in a space such as an anechoic chamber and simultaneously controlling the reflection direction and reflection intensity of electromagnetic waves by the RIS.

[0009] A third object of the present disclosure is to provide a propagation environment reproduction system that accurately reproduces a desired wireless propagation environment by placing a RIS in a space such as an anechoic chamber and simultaneously controlling the direction and intensity of reflection of electromagnetic waves by the RIS. [Means for solving the problem]

[0010] In order to achieve the above object, a first aspect is a propagation environment reproduction device, comprising: RIS (Reconfigurable Intelligent Surface) is installed in a propagation environment reproduction space to reproduce the electromagnetic wave propagation environment, a RIS controller for providing a control signal to the RIS; a transmitting antenna installed in the propagation environment reproduction space; a channel emulator for controlling the characteristics of the electromagnetic wave transmitted from the transmitting antenna; a control server that controls the RIS control device and the channel emulator; The RIS is preferably a reflector having a characteristic of changing its reflection pattern in response to the control signal.

[0011] A second aspect is a propagation environment reproduction method for reproducing a desired propagation environment using a RIS installed in a propagation environment reproduction space for reproducing an electromagnetic wave propagation environment, and a transmitting antenna installed in the propagation environment reproduction space, the method comprising: The RIS is a reflector having a characteristic of changing a reflection pattern in response to a control signal, Calculating, by simulation, propagation characteristics generated in the propagation environment reproduction space under each parameter while changing parameters related to the propagation environment reproduction space, the RIS, and the transmitting antenna; providing a propagation environment model with a combination of actual characteristics, which are propagation characteristics actually measured at measurement positions in real space, and reproduction parameters, which are parameters calculated to generate propagation characteristics identical to the actual characteristics in the propagation environment reproduction space, as training data, to create a learning model that, when a propagation characteristic to be reproduced is given, derives parameters to generate the propagation characteristic in the propagation environment reproduction space; providing desired propagation characteristics to the learning model to cause the learning model to derive parameters for generating the desired propagation characteristics; constructing the propagation environment reproduction space in accordance with the specifications indicated by the parameters derived by the learning model; Arranging the RIS and the transmitting antenna in the propagation environment reproduction space according to the parameters derived by the learning model; controlling the RIS so that the RIS exhibits a reflex pattern indicated by the parameters derived by the learning model; controlling a transmission signal from the transmitting antenna so that the transmitting antenna transmits electromagnetic waves with characteristics indicated by the parameters derived by the learning model; It is desirable to include:

[0012] A third aspect is a propagation environment reproduction system, RIS is installed in a propagation environment reproduction space to reproduce the electromagnetic wave propagation environment, a transmitting antenna installed in the propagation environment reproduction space, The RIS is a reflector having a characteristic of changing a reflection pattern in response to a control signal, the propagation environment reproduction space is configured in accordance with specifications indicated by parameters set to reproduce desired characteristics, which are propagation characteristics occurring at a measurement position in real space; The RIS and the transmitting antenna are arranged according to the specifications indicated by the parameters, a function of controlling the RIS so that the RIS exhibits a reflection pattern indicated by the parameters; a function of controlling a transmission signal from the transmitting antenna so that the transmitting antenna transmits electromagnetic waves with characteristics indicated by the parameters; It is desirable that the optical fiber 100 be configured to have the following characteristics. [Effects of the Invention]

[0013] According to the first to third aspects, the desired radio propagation environment can be accurately reproduced by simultaneously controlling the reflection direction and reflection intensity of the electromagnetic wave by the RIS. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating an overall configuration of a propagation environment reproduction device according to a first embodiment of the present disclosure. [Figure 2] 4 is a flowchart for explaining a procedure for deriving parameters for reproducing a desired propagation environment by the propagation environment reproduction device shown in FIG. [Figure 3A] FIG. 1 is a diagram for explaining one of the typical characteristics that can be given to a RIS. [Figure 3B] FIG. 10 is a diagram for explaining other typical characteristics that can be imparted to the RIS. [Figure 4A] FIG. 1 is a diagram showing reflections occurring in a normal room. [Figure 4B] FIG. 10 is a diagram for explaining the limitations imposed by the RIS for controlling reflected power. [Figure 5] 10A and 10B are diagrams for explaining the characteristics of reflection by the RIS that controls the reflection direction. [Figure 6A] FIG. 10 is a diagram illustrating how the device according to the first embodiment of the present disclosure controls the reflection direction and reflected power at the same time using the RIS that controls the reflection direction. [Figure 6B] FIG. 10 is a diagram illustrating how the device according to the first embodiment of the present disclosure causes an absorber to absorb and eliminate unnecessary reflected signals from the RIS. [Figure 7] 2 is a diagram illustrating a hardware configuration of a control server included in the device according to the first embodiment of the present disclosure. FIG. [Figure 8] 10 is a flowchart illustrating a flow when evaluating communication performance and the like of an object to be measured using an apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Embodiment 1 [Configuration of the First Embodiment] FIG. 1 is a diagram illustrating the overall configuration of a propagation environment reproduction device according to a first embodiment of the present disclosure. The propagation environment reproduction device of this embodiment includes an anechoic chamber 10. The anechoic chamber 10 is a chamber that can block the influence of external electromagnetic waves, and is also referred to as a shielded room or a reverberation chamber. In this embodiment, the anechoic chamber 10 is used for the purpose of reproducing within itself a desired propagation environment for wireless signals, more specifically, a real propagation environment that occurs in a real space such as a city street.

[0016] An object to be measured 12 is placed in the anechoic chamber 10. The object to be measured 12 is, for example, a mobile terminal equipped with multiple antennas for realizing MIMO functionality. In the example shown in FIG. 1 , the object to be measured 12 is placed on a stand 14. The stand 14 is used to hold the object to be measured 12 in a desired space within the anechoic chamber 10. In real spaces such as city streets, a situation may arise in which a mobile terminal or the like is mounted on a drone and positioned in the air. By using the stand 14, the object to be measured 12 can be held at a position within the anechoic chamber 10 that corresponds to the air in real space.

[0017] A plurality of RISs 16 are arranged inside the anechoic chamber 10. The RISs 16 can be installed on the walls, ceiling, or floor of the anechoic chamber 10. The RISs 16 can also be placed in the air inside the anechoic chamber 10 by being supported by a jig installed on the floor or by being suspended from the ceiling (not shown).

[0018] A radio wave absorber 18 can be placed anywhere in the anechoic chamber 10. The radio wave absorber 18 has the function of absorbing irradiated electromagnetic waves. The radio wave absorber 18 can eliminate radio waves inside the anechoic chamber 10 that are unnecessary for simulating a propagation environment in a real space.

[0019] One or more transmitting antennas 20 are arranged in the anechoic chamber 10. The positions of the transmitting antennas 20 can be determined arbitrarily. Figure 1 shows an example in which three transmitting antennas 20 are arranged inside the anechoic chamber 10.

[0020] A RIS control device 22 is connected to the RIS 16. In this embodiment, all RIS 16 are provided with a function for varying the reflection direction of the electromagnetic wave, more specifically, the reflection pattern of the electromagnetic wave. The RIS control device 22 provides a control signal to each of the RIS 16. Each of the RIS 16 changes its reflection pattern in response to the received control signal. Therefore, in this embodiment, each of the RIS 16 installed in the anechoic chamber 10 can be made to form a desired reflection pattern.

[0021] A channel emulator 24 is connected to the transmitting antenna 20. The channel emulator has a function of controlling the characteristics of the electromagnetic waves transmitted from the transmitting antenna 20. Specifically, the channel emulator 24 can control the radiation direction, power, radiation timing, etc. of the electromagnetic waves transmitted from the transmitting antenna 20.

[0022] A control server 26 is connected to the RIS control device 22 and the channel emulator 24. The control server 26 controls the RIS control device 22 and the channel emulator 24 so that a desired propagation environment is reproduced at the position of the receiving antenna provided in the object to be measured 12. By appropriately setting the specifications of the propagation environment reproduction device and then appropriately controlling the RIS control device 22 and the channel emulator 24, it is possible to reproduce a desired propagation environment inside the anechoic chamber 10, particularly at the position of the object to be measured 12.

[0023] 1 is an example of one form of a propagation environment reproduction device. The shape and size of the anechoic chamber 10 can be changed. Its shape can be, for example, a sphere, an n-hedron (n is an integer), an n-sided prism, an n-sided pyramid, etc. Any number of RISs 16 and transmitting antennas 20 greater than or equal to one can be arranged, and the arrangement positions can also be arbitrary.

[0024] [Method for deriving reproduction parameters] FIG. 2 is a flowchart for explaining a procedure for deriving parameters for reproducing a desired propagation environment by the propagation environment reproduction device shown in FIG.

[0025] First, various parameters related to the characteristics of the propagation environment reproduction device are varied, and the propagation characteristics generated in the anechoic chamber 10 under each combination of parameters are calculated by simulation (step 100). The type of simulation may be, for example, ray tracing (ray launching method), ray tracing (imaging method), electromagnetic field analysis (FDTD method), etc.

[0026] The parameters to be set include, for example, the following: The shape, size, and material of the anechoic chamber 10 RIS16 shape, size, number, arrangement, controllable angle, controllable reflectance Location, number and characteristics of the transmitted signal of the transmitting antenna 20 Location, number and characteristics of the received signal of receiving antennas Transmit beam direction - The position, size, number and shape of the radio wave absorber

[0027] The propagation characteristics are the characteristics of the electromagnetic wave at the receiving point, and specifically, the following physical quantities are included: Receiving power ·XPR(Cross Polarization Ratio, vertical horizontal power ratio) Latency ·Arrival direction (horizontal / vertical) Delay spread Angular spread - Number of clusters that make up the radio wave mass

[0028] After the processing of step 100 is completed, the propagation characteristics that are actually generated in the real space (hereinafter referred to as "real characteristics") are identified. Furthermore, parameters that cause the real characteristics to appear in the anechoic chamber 10 (hereinafter referred to as "reproduction parameters") are identified based on the results of the simulation. By repeating this processing, multiple sets of real characteristics and parameters are prepared (step 102).

[0029] The above-mentioned "actual characteristics" are propagation characteristics that are actually measured at the position of the measurement object 12, which is actually placed in a real space such as a city street. The "reproduction parameters" are parameters obtained by simulating how to generate the "actual characteristics" inside the anechoic chamber 10. Therefore, if a propagation environment reproduction device is prepared according to the reproduction parameters, the same characteristics as the above-mentioned "actual characteristics" should be generated inside the device.

[0030] The set of "actual characteristics" and "reproduction parameters" is used as training data for machine learning. That is, in this embodiment, the multiple data sets prepared in step 102 above are provided to the propagation environment model as training data for machine learning. Then, by repeating learning using a large amount of training data, when an actual characteristic is given, a learning model is created that derives parameters that will generate that characteristic in the anechoic chamber 10 (step 104).

[0031] Once the learning model has been created, the propagation characteristics to be reproduced in the anechoic chamber 10 (hereinafter referred to as "desired characteristics") are provided to the learning model (step 106).

[0032] As a result, parameters for generating desired characteristics in the anechoic chamber 10 are derived from the learning model (step 108).

[0033] Thereafter, a propagation environment reproducing device is prepared in accordance with the parameters derived in step 108, and electromagnetic waves are transmitted into the device, thereby reproducing the desired characteristics at the position of the object 12 in the anechoic chamber 10 (step 110).

[0034] Once the desired characteristics have been reproduced, the communication performance, communication quality, etc. of the object 12 placed in the anechoic chamber 10 are measured, and the results are evaluated (step 112).

[0035] As described above, the propagation environment reproducing apparatus of this embodiment can reproduce desired characteristics in the anechoic chamber 10 and evaluate the object to be measured 12. Therefore, this apparatus can accurately evaluate the capabilities exhibited by the object to be measured 12 in real space without performing measurements in real space.

[0036] [RIS characteristics] Fig. 3A is a diagram illustrating an example of a characteristic that can be imparted to a RIS using metamaterial technology. As shown in Fig. 3A, the RIS can be given the characteristic of changing the direction in which it reflects an incident wave in response to a control signal provided by a controller.

[0037] Figure 3B shows other typical characteristics that can be imparted to a RIS. As shown in Figure 3B, the RIS can be given characteristics such as transmitting incident waves, concentrating reflected waves at a specific location, absorbing part of the incident wave and reflecting it with reduced intensity, and scattering the incident wave. Depending on the structure adopted, the RIS can be selectively given characteristics such as those shown in Figure 3B in addition to the characteristics shown in Figure 3A.

[0038] The RIS 16 used in this embodiment has the characteristic shown in Fig. 3A, that is, the characteristic of varying the direction of the reflected wave. More specifically, the RIS 16 of this embodiment has the characteristic of varying the reflection pattern in response to a control signal.

[0039] Figure 4A shows the reflection that occurs in a normal room. In this case, the electromagnetic waves emitted from the transmitting antenna 20 are reflected by the wall surface, changing their direction of travel. The angle of incidence of the electromagnetic waves on the wall surface is the same as the angle of reflection of the electromagnetic waves on the wall surface. Furthermore, the power 1 after reflection remains approximately equal to the transmission power 1.

[0040] FIG. 4B shows the reflection behavior when a RIS with variable reflected power is placed on the wall of the anechoic chamber 10. Path 28 in FIG. 4B represents the desired path for the electromagnetic wave to be incident on the receiving point where the object 12 is located. Meanwhile, path 30 represents the path that actually occurs in this example. The RIS in FIG. 4B reflects the electromagnetic wave at the same reflection angle as in FIG. 4A. Therefore, unless the transmitting antenna 20 and the object 12 are symmetrically positioned with respect to each other across the RIS, the reflected electromagnetic wave will not reach the object 12. Thus, while a RIS with variable reflected power can control the reflected power, it may not be possible for the resulting reflected wave to reach the object 12. In other words, a RIS with such characteristics cannot direct a reflected wave with the desired power in the desired direction.

[0041] FIG. 5 is a diagram for explaining in detail the reflection characteristics of the RIS 16 used in this embodiment. As described above, the RIS 16 is given a characteristic that allows it to change the reflection direction in response to a control signal. FIG. 5 shows an example of a reflection pattern formed by providing a specific control signal to the RIS 16. Here, the largest reflection occurs in the reflection direction of path 32. Also, an attenuated reflection occurs in the direction of path 34. The reflection pattern of the RIS 16 changes in response to the control signal. Therefore, if a receiving antenna is present in the direction of path 34, and a reflection pattern is generated such that the reflection in the direction of path 34 has the desired power, the RIS 16 can control both the direction and intensity of the reflection.

[0042] [Example of controlling reflection direction and reflection intensity] 6A shows an example of how the RIS 16 simultaneously controls the reflection direction and reflected power of an electromagnetic wave transmitted from the transmitting antenna 20. Here, an electromagnetic wave with a power of 1 is transmitted from the transmitting antenna toward the RIS 16, and the RIS 16 reflects an electromagnetic wave with a power of 0.5 in the incident direction toward the object 12. In this way, by generating the reflection pattern shown in FIG. 6A in the RIS 16, a reflected wave with half the power can be made to enter the object 12. In this case, it is assumed that the reflected waves traveling in directions other than the direction toward the object 12 are dispersed to an extent that they do not affect the propagation environment at the receiving point.

[0043] FIG. 6B shows an example in which a desired propagation environment is created by absorbing unwanted reflected waves using a radio wave absorber 18. When generating a reflected wave of desired intensity toward the object 12, the RIS 16 shown in FIG. 6B generates a high-intensity reflected wave in the direction of path 38. Here, the reflected wave from path 38 is reflected by the RIS 16 and directed toward the radio wave absorber 18. The radio wave absorber 18 has the function of absorbing electromagnetic waves. Therefore, the high-intensity reflected wave toward path 38 does not affect the propagation environment at the location where the object 12 is placed. As a result, a desired propagation space is reproduced inside the anechoic chamber 10, regardless of the generation of a reflected wave in the direction of path 38.

[0044] [Control server hardware configuration] 7 shows the hardware configuration of the control server 26. The control server 26 is configured as a general computer system and includes a central processor (CPU) 40. Memory such as a ROM 44, a RAM 46, and a storage 48 is connected to the CPU 40 via a communication bus 42. A communication interface 50, an operation unit 52 serving as a user interface, and a display unit 54 are also connected to the communication bus 42.

[0045] The control server 26 realizes the above-mentioned various functions by the CPU 40 executing the programs stored in the ROM 44. Specifically, the control server 26 realizes the simulation in step 100, the learning in step 104, the parameter derivation in step 108, the control of the RIS 16 and the channel emulator 24 in step 110, and the evaluation of the object 12 in step 112 by the CPU 40 proceeding with processing in accordance with the above-mentioned programs.

[0046] [Evaluation of the measured object] 8 is a flowchart for explaining in detail the processing of steps 110 and 112 shown in FIG. 2. Here, first, the anechoic chamber 10 is set up (step 120). Specifically, the anechoic chamber 10 is set up with the shape, size, and material indicated by the parameters derived in step 108 above. Furthermore, the RIS 16, transmitting antenna 20, and receiving antenna (object to be measured 12) are set up within the anechoic chamber 10 according to the above parameters. If the parameters require the installation of a radio wave absorber 18, this is also installed.

[0047] Next, the control server 26 controls the RIS controller 22 and the channel emulator 24 as indicated by the above parameters (step 122).

[0048] As a result, a desired propagation environment that simulates the characteristics of real space is reproduced inside the anechoic chamber 10, particularly at the position of the measurement object 12 (step 124). In this step, it may be verified that the desired propagation environment has been reproduced using a receiving antenna with known performance.

[0049] Once the desired propagation space has been recreated in the anechoic chamber 10, the control server 26 measures the communication quality and the like of the object 12 (step 126).

[0050] Next, the control server 26 is caused to perform an evaluation of the measurement object 12 based on the measurement results (step 128).

[0051] [Modification of the first embodiment] In the above example, the simulation in step 100, the learning in step 104, and the parameter derivation in step 108 are performed by the control server 26, but the present disclosure is not limited to this. These processes may be performed by another computer prepared separately from the control server 26.

[0052] In the above example, the control server 26 is configured to measure the communication quality of the object 12 and evaluate the object 12 based on the measurement results, but the present disclosure is not limited to this. These processes may be performed by another evaluation device prepared separately from the control server 26.

[0053] In the first embodiment described above, the propagation environment in real space is reproduced in the anechoic chamber 10. However, the present disclosure is not limited to this. The space in which the propagation environment is reproduced may be an outdoor space or a normal indoor space that does not have a shielding function. [Explanation of symbols]

[0054] 10 Radio Wave Anechoic Chamber 12 Measurement object 16 RIS 18 Radio wave absorber 20 transmitting antennas 22 RIS control device 24 channel emulator 26 Control Server 40 CPU 44 ROM

Claims

1. RIS (Reconfigurable Intelligent Surface) is installed in a propagation environment reproduction space to reproduce the electromagnetic wave propagation environment, a RIS controller for providing a control signal to the RIS; a transmitting antenna installed in the propagation environment reproduction space; a channel emulator for controlling the characteristics of the electromagnetic wave transmitted from the transmitting antenna; a control server that controls the RIS control device and the channel emulator; the control server receives desired characteristics, which are propagation characteristics occurring at a measurement position in real space, and controls the RIS control device and the channel emulator so that the desired characteristics are realized; the control signal is a signal for realizing the desired characteristic, The RIS is a propagation environment reproduction device that is a reflector having a characteristic of changing a reflection pattern in response to the control signal.

2. the propagation environment reproduction space is configured according to specifications indicated by parameters set to reproduce the desired characteristics, The RIS and the transmitting antenna are arranged according to the specifications indicated by the parameters, The control server controlling the RIS control device so that the RIS exhibits a reflection pattern indicated by the parameters; 2. The propagation environment reproducing device according to claim 1, further comprising: a process for controlling the channel emulator so that the transmitting antenna transmits electromagnetic waves with characteristics indicated by the parameters.

3. 3. The propagation environment reproduction device according to claim 2, wherein the reflection pattern is a pattern that generates a reflection of a desired intensity in a direction toward a measurement position within the propagation environment reproduction space.

4. 3. The propagation environment reproduction device according to claim 2, further comprising a radio wave absorber installed in the propagation environment reproduction space so as to absorb electromagnetic waves reflected by the RIS under the reflection pattern in a direction different from the direction toward the measurement position.

5. A propagation environment reproduction method for reproducing a desired propagation environment using a RIS installed in a propagation environment reproduction space for reproducing an electromagnetic wave propagation environment and a transmitting antenna installed in the propagation environment reproduction space, comprising: The RIS is a reflector having a characteristic of changing a reflection pattern in response to a control signal, Calculating, by simulation, propagation characteristics generated in the propagation environment reproduction space under each parameter while changing parameters related to the propagation environment reproduction space, the RIS, and the transmitting antenna; providing a propagation environment model with a combination of actual characteristics, which are propagation characteristics actually measured at measurement positions in real space, and reproduction parameters, which are parameters calculated to generate propagation characteristics identical to the actual characteristics in the propagation environment reproduction space, as training data, to create a learning model that, when a propagation characteristic to be reproduced is given, derives parameters to generate the propagation characteristic in the propagation environment reproduction space; providing desired propagation characteristics to the learning model to cause the learning model to derive parameters for generating the desired propagation characteristics; constructing the propagation environment reproduction space in accordance with the specifications indicated by the parameters derived by the learning model; Arranging the RIS and the transmitting antenna in the propagation environment reproduction space according to the parameters derived by the learning model; controlling the RIS so that the RIS exhibits a reflex pattern indicated by the parameters derived by the learning model; controlling a transmission signal from the transmitting antenna so that the transmitting antenna transmits electromagnetic waves with characteristics indicated by the parameters derived by the learning model; A method for reproducing a propagation environment including:

6. 6. The propagation environment reproduction method according to claim 5, wherein the reflection pattern is a pattern that generates a reflection of a desired intensity in a direction toward a measurement position in the propagation environment reproduction space.

7. The propagation environment reproduction method according to claim 6, further comprising installing a radio wave absorber in the propagation environment reproduction space that absorbs electromagnetic waves reflected by the RIS under the reflection pattern in a direction different from a direction toward the measurement position.

8. RIS is installed in a propagation environment reproduction space to reproduce the electromagnetic wave propagation environment, a transmitting antenna installed in the propagation environment reproduction space, The RIS is a reflector having a characteristic of changing a reflection pattern in response to a control signal, the propagation environment reproduction space is configured in accordance with specifications indicated by parameters set to reproduce desired characteristics, which are propagation characteristics occurring at a measurement position in real space; The RIS and the transmitting antenna are arranged according to the specifications indicated by the parameters, receiving the desired characteristic; deriving the parameters from the desired characteristics; a function of providing the RIS with a control signal for realizing a reflection pattern indicated by the parameter; a function of controlling a transmission signal from the transmitting antenna so that the transmitting antenna transmits electromagnetic waves with characteristics indicated by the parameters; A propagation environment reproduction system configured to have the following.

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