Radio wave propagation environment reproduction system and radio wave propagation environment reproduction method

Abstract

A radio-wave propagation environment reproduction system according to an embodiment of this invention includes: a transmission device that transmits a radio wave in a predetermined direction in a reverberation chamber; a reflection angle changing RIS that reflects the radio wave transmitted by the transmission device at an angle according to a control signal; an installation angle control device that outputs a control signal to the reflection angle changing RIS to control the installation angle of the reflection angle changing RIS; a reflection angle control device that outputs a control signal to the reflection angle changing RIS to control the reflection angle of the radio wave reflected by the reflection angle changing RIS; a direction-of-arrival estimation device that estimates the direction of arrival of the radio wave reflected by the reflection angle changing RIS at a predetermined position in the reverberation chamber; and a control server that controls the installation angle control device and the reflection angle control device on the basis of the direction of arrival of the radio wave estimated by the direction-of-arrival estimation device.

Description

Technical Field

[0001] The present invention relates to a radio wave propagation environment reproduction system and a radio wave propagation environment reproduction method.

Background Art

[0002] When attempting to conduct a communication evaluation of a wireless terminal that uses a frequency above the millimeter wave band, such as 5G (the fifth-generation mobile communication system), by wire, the configuration is often complicated or structurally impossible.

[0003] Therefore, attempts have been made to wirelessly transmit and receive high-frequency signals to quickly and simply evaluate a target device (OTA test: over the air test).

[0004] For example, there is a method called Reverberation chamber-based method with or without a channel emulator (RC and RC + CE) in which a stirrer (a plate that scatters radio waves) is placed in a reverberation chamber (a room surrounded by metal plates) to emulate a statistically isotropic multipath environment.

[0005] In addition, there are methods such as a method in which a large number of antennas and RISs (Reconfigurable Intelligent Surfaces: reflectors that can arbitrarily control the reflection characteristics of radio waves) are installed in a reverberation chamber, parameters are determined by simulation and machine learning, and an arbitrary radio wave propagation environment is reproduced, and the MPAC (Multi Probe Anechoic Chamber) method (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, for example, when a stirrer is placed in an anechoic chamber to emulate a statistically isotropic multipath environment, only a propagation channel with an isotropic three-dimensional distribution can be generated. Also, the reproducible propagation channel is determined by the shape of the stirrer and the size of the anechoic chamber. Therefore, the reproducible propagation channels are limited when using the same stirrer, and it was necessary to change the stirrer to another one in order to reproduce a different propagation channel.

[0008] Also, when a large number of antennas and RISs are installed in an anechoic chamber and parameters are determined by simulation and machine learning, advanced expertise, as well as high-performance computers and software, were required.

[0009] The present invention has been made in view of the above-described problems, and an object thereof is to provide a radio wave propagation environment reproduction system and a radio wave propagation environment reproduction method that can facilitate the reproduction of a complex radio wave propagation environment.

Means for Solving the Problems

[0010] The radio wave propagation environment reproduction system according to an embodiment of the present invention includes a transmission device that transmits radio waves in a predetermined direction in anechoic chamber, a reflection angle change RIS that reflects the radio waves transmitted by the transmission device at an angle according to a control signal, an installation angle control device that controls the installation angle of the reflection angle change RIS by outputting a control signal to the reflection angle change RIS, a reflection angle control device that controls the reflection angle of the radio waves by the reflection angle change RIS by outputting a control signal to the reflection angle change RIS, an arrival direction estimation device that estimates the arrival direction of the radio waves reflected by the reflection angle change RIS at a predetermined position in the anechoic chamber, and a control server that controls the installation angle control device and the reflection angle control device based on the arrival direction of the radio waves estimated by the arrival direction estimation device.

[0011] Further, the radio wave propagation environment reproduction system according to an embodiment of the present invention includes a transmission device that transmits radio waves in a predetermined direction in anechoic chamber, a reflector that reflects the radio waves transmitted by the transmission device, an installation angle control device that controls the installation angle of the reflector by outputting a control signal to the reflector, a reflection power change RIS that changes and reflects the radio waves reflected by the reflector to a power according to a control signal, a reflection power control device that controls the power of the radio waves reflected by the reflection power change RIS by outputting a control signal to the reflection power change RIS, an arrival direction estimation device that estimates the arrival direction of the radio waves reflected by the reflection power change RIS at a predetermined position in the anechoic chamber, and a control server that controls the installation angle control device and the reflection power control device based on the arrival direction of the radio waves estimated by the arrival direction estimation device.

[0012] In addition, a radio wave propagation environment reproduction method according to an embodiment of the present invention includes a step of controlling an installation angle of a reflection angle change RIS that reflects radio waves transmitted by a transmission device in a predetermined direction in an anechoic chamber at an angle corresponding to a control signal, a step of controlling a reflection angle of the radio waves reflected by the reflection angle change RIS by a control signal, a step of estimating a direction of arrival of the radio waves reflected by the reflection angle change RIS at a predetermined position in the anechoic chamber, and a step of controlling the installation angle and the reflection angle of the reflection angle change RIS based on the estimated direction of arrival of the radio waves.

[0013] In addition, a radio wave propagation environment reproduction method according to an embodiment of the present invention includes a step of controlling an installation angle of a reflector that reflects radio waves transmitted by a transmission device in a predetermined direction in an anechoic chamber, a step of controlling a reflection power of the radio waves reflected by the reflector for a reflection power change RIS that changes and reflects power according to a control signal, a step of estimating a direction of arrival of the radio waves reflected by the reflection power change RIS at a predetermined position in the anechoic chamber, and a step of controlling the installation angle of the reflector and the power of the radio waves reflected by the reflection power change RIS based on the estimated direction of arrival of the radio waves.

Effects of the Invention

[0014] According to the present invention, it is possible to facilitate the reproduction of a complex radio wave propagation environment.

Brief Description of the Drawings

[0015]

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Figure 14

Embodiments for Carrying Out the Invention

[0016] First, the background leading to the present invention will be described. FIG. 13 is a diagram showing the configuration of a radio wave propagation environment reproduction system 1 of a comparative example. As shown in FIG. 13, the radio wave propagation environment reproduction system 1 of the comparative example includes a base station emulator 2, a propagation emulator 3, and anechoic chamber 4.

[0017] Inside the anechoic chamber 4, a plurality of wall antennas 5, a stirrer 6, and an antenna 7 are provided, and a measurement target terminal 8 is installed. The anechoic chamber 4 constitutes a space for reverberating radio waves, and its size and shape can be changed. For example, the anechoic chamber 4 can be formed in a shape such as a rectangular parallelepiped, a sphere, an n-sided polyhedron, an n-sided prism, or an n-sided pyramid.

[0018] The radio wave propagation environment reproduction system 1 can emulate a statistically isotropic multipath environment, but in order to perform propagation measurements according to various propagation environments, it was necessary to change the shape of the stirrer 6.

[0019] FIG. 14 is a diagram showing the configuration of a radio wave propagation environment reproduction system 1a of another comparative example. As shown in FIG. 14, the radio wave propagation environment reproduction system 1a includes a control server 11, a channel emulator 12, an RIS control device 13, and anechoic chamber 14.

[0020] Inside the anechoic chamber 14, a plurality of transmission antennas 140, radio wave absorbers 141, and a plurality of RISs 142 are provided. The plurality of RISs 142 are stretched on the inner walls, floor, and ceiling of the anechoic chamber 14, and are also provided in the air inside the anechoic chamber 14 using jigs. And a terminal serving as the measurement object 143 is installed inside the anechoic chamber 14.

[0021] The radio wave propagation environment reproduction system 1a can reproduce the radio wave propagation environment inside the anechoic chamber 14 by the RIS control device 13 controlling the reflection direction of each RIS 142, but in order to control the reflection direction of the RIS 142, complex machine learning was required.

[0022] Thus, in the radio wave propagation environment reproduction system of the comparative example, changes to the agitator and complex machine learning are required, and it may not be easy to reproduce a complex radio wave propagation environment. Therefore, the radio wave propagation environment reproduction system according to one embodiment is configured to facilitate the reproduction of a complex radio wave propagation environment.

[0023] Hereinafter, a first embodiment of the radio wave propagation environment reproduction system will be described with reference to the drawings. First, with reference to FIGS. 1 and 2, an overview of the radio wave propagation environment reproduction system 10 according to the first embodiment will be described.

[0024] FIG. 1 is a diagram showing an overview of the configuration of the radio wave propagation environment reproduction system 10 according to the first embodiment. FIG. 2 is a diagram showing an overview of the functions of the radio wave propagation environment reproduction system 10 according to the first embodiment.

[0025] The radio wave propagation environment reproduction system 10 includes a control server 20, an installation angle control device 21, a channel emulator 22, a reflection angle control device 23, and anechoic chamber 30.

[0026] Inside the anechoic chamber 30, a transmission device 40, a reflection angle changing RIS 41, a mounting table 42, radio wave absorbers 43, and an arrival direction estimation device 44 are provided.

[0027] The control server 20 functions as a computer and controls each part constituting the radio wave propagation environment reproduction system 10. For example, the control server 20 controls the installation angle control device 21, the channel emulator 22, and the reflection angle control device 23 based on the arrival direction of the radio waves estimated by the arrival direction estimation device 44 as described later.

[0028] The installation angle control device 21 controls the installation angle of the reflection angle changing RIS 41 by outputting a control signal to the reflection angle changing RIS 41.

[0029] The channel emulator 22 generates a transmission signal corresponding to a predetermined propagation channel in response to the control of the control server 20 and outputs it to the transmission device 40.

[0030] The reflection angle control device 23 controls the reflection angle of the radio wave by the reflection angle change RIS 41 by outputting a control signal to the reflection angle change RIS 41.

[0031] The transmission device 40 transmits radio waves in a predetermined direction in the reverberation chamber 30. For example, as will be described later, the transmission device 40 has an antenna whose half-value angle indicating directivity coincides with the visible range with respect to the reflection angle change RIS 41.

[0032] The reflection angle change RIS 41 is a RIS (Reconfigurable Intelligent Surface: a reflector that arbitrarily controls the reflection characteristics of radio waves) that reflects the radio wave transmitted by the transmission device 40 at an angle according to the control signal.

[0033] The mounting table 42 is configured to be able to change the position and height of the arrival direction estimation device 44 in the reverberation chamber 30. Further, the mounting table 42 can mount a receiving device to be measured instead of the arrival direction estimation device 44.

[0034] The radio wave absorber 43 absorbs the radio wave incident in the reverberation chamber 30. For example, the radio wave absorber 43 makes the environment outside the visible range from the transmission device 40 to the arrival direction estimation device 44. Therefore, since all the radio waves in the reverberation chamber 30 are always reflected by the reflection angle change RIS 41, they are always the target of reflection direction control before reaching the arrival direction estimation device 44 (or the receiving device to be measured).

[0035] The arrival direction estimation device 44 estimates the arrival direction of the radio wave reflected by the reflection angle change RIS 41 at a predetermined position in the reverberation chamber 30 and outputs the estimation result to the control server 20.

[0036] For example, the arrival direction estimation device 44 includes a narrow-directional antenna that rotates at a constant angle in the elevation angle and the horizontal angle, and measures radio waves from all directions. Further, the arrival direction estimation device 44 may be configured to perform beamforming with an array antenna (such as a cylindrical array, a linear array, a square array, etc.) (MUSIC: MUltiple Signal Classifiation, ESPRIT: Estimation of Signal Parameters via Rotational Invariance Techniques), or may be configured to perform compressive sensing (ISTA: Iterative Shrinkage Thresholding Algorithm, FISTA: Fast ISTA).

[0037] The radio wave propagation environment reproduction system 10 shown in FIGS. 1 and 2 enables the operation of the reflection direction of radio waves in the reverberation chamber 30 by reflecting the radio waves radiated by the transmission device 40 once to the reflection angle-changing RIS 41. That is, the radio wave propagation environment reproduction system 10 can control the reflection direction of radio waves by controlling the reflection angle-changing RIS 41, and can control the arrival direction of radio waves reaching the arrival direction estimation device 44.

[0038] The radio wave propagation environment reproduction system 10 controls the reflection direction of the reflection angle-changing RIS 41 while changing the installation angle of the reflection angle-changing RIS 41. The arrival direction estimation device 44 estimates the arrival direction of the radio waves and outputs it to the control server 20.

[0039] Based on the arrival direction of the radio waves estimated by the arrival direction estimation device 44, the control server 20 sets the installation angle of the reflection angle-changing RIS 41 that can reproduce a desired propagation channel, and controls the reflection direction of the reflection angle-changing RIS 41.

[0040] Next, the vicinity of the transmission device 40 in the reverberation chamber 30 will be described in detail. FIG. 3 is a diagram showing an installation example of the transmission device 40 (antenna included in the transmission device 40), the radio wave absorber 43, and the reflection angle-changing RIS 41.

[0041] For example, in the radio wave propagation environment reproduction system 10, the antenna position (x Tx , y Tx , z Tx ) of the transmission device 40, the size (x Ab , y Ab , z Ab ) of the radio wave absorber 43, the size (x Rf , y Rf ) of the reflection angle change RIS 41, the position (z Rf ) of the reflection angle change RIS 41, and the angles (θ Rf , φ Rf ) of the reflection angle change RIS 41 are set.

[0042] Also, in the radio wave propagation environment reproduction system 10, the size (x Ab_w , y Ab_w ) of the radio wave absorber 43 on the wall side is set to adjust the directivity of the antenna of the transmission device 40.

[0043] The reflection angle change RIS 41 is in close contact with each inner wall of the reverberation chamber 30 without gaps. Also, the radio wave absorber 43 surrounds, for example, the four sides and the bottom surface of the antenna of the transmission device 40. Also, the radio wave absorber 43 on the inner wall side of the reverberation chamber 30 has a height up to the reflection angle change RIS 41 and is wider than the inner radio wave absorber 43.

[0044] FIG. 4 is a diagram showing a state of viewing the reflection angle change RIS 41 from the height of the antenna of the transmission device 40. FIG. 4(a) is a diagram of viewing the reflection angle change RIS 41 from the height of the antenna of the transmission device 40. FIG. 4(b) is a diagram showing the actual appearance when viewing the reflection angle change RIS 41 from the height of the antenna of the transmission device 40.

[0045] The reflection angle change RIS 41 is arranged so as to occupy the entire range surrounded by the radio wave absorber 43 when viewed from the height of the antenna of the transmission device 40 in order to reflect all the radio waves radiated by the transmission device 40.

[0046] FIG. 5 is a side view showing an installation example of the transmission device 40 (antenna included in the transmission device 40), the radio wave absorber 43, and the reflection angle changing RIS 41. FIG. 5(a) is a view of the transmission device 40, the radio wave absorber 43, and the reflection angle changing RIS 41 seen from the y direction. FIG. 5(b) is a view of the transmission device 40, the radio wave absorber 43, and the reflection angle changing RIS 41 seen from the x direction.

[0047] Here, the arrangement is set to satisfy the following conditions. <Condition> In the x-z plane, for all Y where y = Y (0 ≤ Y ≤ y Ab ), and in the y-z plane, for all X where x = X (0 ≤ X ≤ x Ab ), x´ TxRf ≤ x´ Rf and y´ TxRf ≤ y´ Rf are satisfied.

[0048] Also, the antenna position (x Tx , y Tx , z Tx ) of the transmission device 40, the size (x Ab , y Ab , z Ab ) of the radio wave absorber 43, the size (x Rf , y Rf ) of the reflection angle changing RIS 41, the position (z Rf ) of the reflection angle changing RIS 41, and the angles (θ Rf , φ Rf ) of the reflection angle changing RIS 41 are set.

[0049] FIG. 6 is a diagram illustrating the size of the radio wave absorber 43. Here, the size (x Ab , y Ab , z Ab ) of the radio wave absorber 43 on the wall side of the reverberation chamber 30 is set, and ·x Ab_w = x Ab ·y Ab_w = y Ab When this is done, the gaps A1 and A2 generated between the radio wave absorber 43 and the reflection angle changing RIS 41 are filled.

[0050] FIG. 7 is a diagram showing the positional relationship between the range of radio waves radiated by the transmission device 40, the radio wave absorber 43, and the reflection angle change RIS 41. FIG. 7(a) is a diagram showing the positional relationship between the range of radio waves radiated by the transmission device 40, the radio wave absorber 43, and the reflection angle change RIS 41 from the y direction. Specifically, it shows the size x of the radio wave absorber 43 installed on the x-z plane (wall) when y = 0 Ab_w is shown. FIG. 7(b) is a diagram showing the positional relationship between the range of radio waves radiated by the transmission device 40, the radio wave absorber 43, and the reflection angle change RIS 41 from the x direction. Specifically, it shows the size y of the radio wave absorber 43 installed on the y-z plane (wall) when x = 0 Ab_w is shown.

[0051] As shown by the thick dashed line in FIG. 7, the radio waves radiated by the transmission device 40 reach the reflection angle change RIS 41 within the range up to the straight line passing through the edge of the radio wave absorber 43.

[0052] FIG. 8 is a diagram showing the half-value angle of the radio waves radiated by the transmission device 40. FIG. 8(a) is a view of the half-value angle of the radio waves radiated by the transmission device 40 seen from the y direction. FIG. 8(b) is a view of the half-value angle of the radio waves radiated by the transmission device 40 seen from the x direction.

[0053] As shown in FIG. 8, it is desirable that the range of the radio waves reaching the reflection angle change RIS 41 of the antenna of the transmission device 40 coincides with the half-value angle of the directivity of the antenna as follows.

[0054] <Condition> For example, in the x-z plane, for all Y where y = Y (0 ≤ Y ≤ y Ab ), and in the y-z plane, for all X where x = X (0 ≤ X ≤ x Ab ), in order to improve the energy efficiency, ideally, the angle θ Tx_HW , φ Tx_HW is such that the range within the line of sight from the antenna of the transmission device 40 to the reflection angle change RIS 41 coincides with the half-value width of the directivity.

[0055] Next, the processing performed by the radio wave propagation environment reproduction system 10 will be described. FIG. 9 is a diagram exemplifying in order the processing performed by the radio wave propagation environment reproduction system 10. As shown in FIG. 9, an operator installs the arrival direction estimation device 44 at a predetermined position on the mounting table 42 in the reverberation chamber 30 (S100).

[0056] The control server 20 generates a transmission signal by the channel emulator 22 (S102), and causes the transmission device 40 to transmit the generated signal (S104).

[0057] The installation angle control device 21 changes the installation angle of the reflection angle changing RIS 41 (S106). The reflection angle control device 23 switches the direction in which the reflection angle changing RIS 41 reflects radio waves (S108).

[0058] Next, the arrival direction estimation device 44 measures (estimates) the arrival direction of the radio wave, and outputs the estimation result to the control server 20 (S110).

[0059] Then, the control server 20 performs control to repeat the processing of S108 and S110 until the reflection angle changing RIS 41 changes the reflection direction and the arrival direction estimation device 44 estimates the arrival direction in all ranges of the arrival direction of the radio wave at a predetermined position.

[0060] Also, the control server 20 repeats the processing so that the processing of S106 to S110 is executed in all ranges (all angles of the movable range) that can be set for the reflection angle changing RIS 41.

[0061] Thereafter, the operator installs a receiving device to be measured at the position where the arrival direction estimation device 44 was installed (S112). That is, the arrival direction estimation device 44 is replaced with the receiving device.

[0062] The control server 20 controls the installation angle and the reflection direction of the reflection angle changing RIS 41 by controlling the installation angle control device 21 and the reflection angle control device 23, and generates a desired propagation channel from the transmission device 40 (S114). That is, the radio wave propagation environment reproduction system 10 reproduces the radio wave propagation environment.

[0063] The receiving device replaced by the arrival direction estimation device 44 receives radio waves. Then, for example, the control server 20 performs evaluation of the propagation characteristics of the radio waves received by the receiving device (S116).

[0064] In this way, the radio wave propagation environment reproduction system 10 can reproduce a more complex propagation channel, such as the case where radio waves arrive only from a certain direction, not only an isotropic propagation channel, by changing the installation angle and reflection direction of the reflection angle change RIS 41.

[0065] Next, a second embodiment of the radio wave propagation environment reproduction system will be described with reference to the drawings. First, with reference to FIGS. 10 and 11, an overview of the radio wave propagation environment reproduction system 10a according to the second embodiment will be described.

[0066] FIG. 10 is a diagram showing an overview of the configuration of the radio wave propagation environment reproduction system 10a according to the second embodiment. FIG. 11 is a diagram showing an overview of the functions of the radio wave propagation environment reproduction system 10a according to the second embodiment.

[0067] The radio wave propagation environment reproduction system 10a includes a control server 20a, an installation angle control device 21a, a channel emulator 22, a reflected power control device 24, and an anechoic chamber 30a. Hereinafter, the same reference numerals are given to substantially the same configurations as those of the radio wave propagation environment reproduction system 10 shown in FIG. 1.

[0068] In the anechoic chamber 30a, a transmission device 40, a mounting table 42, a radio wave absorber 43, a reflector 45, a plurality of reflected power change RISs 46, and an arrival direction estimation device 44 are provided.

[0069] The control server 20a has functions as a computer and controls each part constituting the radio wave propagation environment reproduction system 10a. For example, the control server 20a controls the installation angle control device 21a, the channel emulator 22, and the reflected power control device 24 based on the arrival direction of the radio waves estimated by the arrival direction estimation device 44.

[0070] The installation angle control device 21a controls the installation angle of the reflector 45 by outputting a control signal to the reflector 45.

[0071] The channel emulator 22 generates a transmission signal corresponding to a predetermined propagation channel in response to the control of the control server 20a and outputs it to the transmission device 40.

[0072] The reflected power control device 24 controls the power of the radio wave reflected by the reflected power change RIS 46 by outputting a control signal to the reflected power change RIS 46.

[0073] The transmission device 40 has an antenna with a half-value angle indicating directivity that matches the visible range with respect to the reflector 45.

[0074] The reflector 45 reflects (primary reflection) the radio wave transmitted by the transmission device 40. Note that the positional relationship between the reflector 45 and the transmission device 40 is the same as the positional relationship between the reflection angle change RIS 41 and the transmission device 40 described above.

[0075] The reflected power change RIS 46 changes the power of the radio wave reflected by the reflector 45 to the power according to the control signal and then reflects it. For example, the reflected power change RIS 46 changes the magnitude of the reflected power according to the control signal or turns off the reflected power (OFF). And a plurality of reflected power change RIS 46 are laid on, for example, the inner walls, floor, ceiling, etc. inside the reverberation chamber 30a.

[0076] Then, the arrival direction estimation device 44 estimates the arrival direction of the radio wave reflected by the reflected power change RIS 46 at a predetermined position in the reverberation chamber 30a and outputs the estimation result to the reverberation chamber 30a.

[0077] The radio wave propagation environment reproduction system 10a shown in FIGS. 10 and 11 can manipulate the reflection direction of radio waves in the reverberation chamber 30a by reflecting the radio waves radiated by the transmitting device 40 once on the reflector 45 (primary reflector). That is, the radio wave propagation environment reproduction system 10a controls the reflection direction of radio waves by controlling the installation angle of the reflector 45 and the reflection power of the reflection power change RIS 46, and can control the arrival direction and power of the radio waves reaching the arrival direction estimation device 44.

[0078] The radio wave propagation environment reproduction system 10a switches the ON / OFF of the reflection power change RIS 46 in order while changing the angle of the reflector 45, estimates the arrival direction of the radio waves by the arrival direction estimation device 44 and which reflection power change RIS 46 is reflecting the radio waves, and outputs it to the control server 20a.

[0079] Based on the arrival direction of the radio waves estimated by the arrival direction estimation device 44, the control server 20a controls the installation angle of the reflector 45 and the reflection power of each of the reflection power change RIS 46 so as to reproduce a desired propagation channel.

[0080] Next, the processing performed by the radio wave propagation environment reproduction system 10a will be described. FIG. 12 is a diagram exemplifying in order the processing performed by the radio wave propagation environment reproduction system 10a. As shown in FIG. 12, the operator installs the arrival direction estimation device 44 at a predetermined position on the mounting table 42 in the reverberation chamber 30a (S200).

[0081] The control server 20a generates a transmission signal by the channel emulator 22 (S202), and causes the transmitting device 40 to transmit the generated signal (S204).

[0082] The installation angle control device 21a changes the installation angle of the reflector 45 (S206). The reflection power control device 24 controls the power with which each of the reflection power change RIS 46 reflects radio waves. For example, the reflection power control device 24 switches the ON / OFF of each of the reflection power change RIS 46 (S208).

[0083] Next, the arrival direction estimation device 44 measures (estimates) the arrival direction of the radio wave and outputs the estimation result to the control server 20a (S210).

[0084] Then, the control server 20a performs control to repeat the processes of S208 and S210 until each of the reflector 45 and the reflection power change RIS 46 changes the reflection direction and the arrival direction estimation device 44 estimates the arrival direction over the entire range of the arrival direction of the radio wave at a predetermined position.

[0085] Also, the control server 20a repeats the process so that the processes of S206 to S210 are executed in all ranges (all angles of the movable range) that can be set for the reflector 45.

[0086] After that, the operator installs the receiving device to be measured at the position where the arrival direction estimation device 44 was installed (S212). That is, the arrival direction estimation device 44 is replaced with the receiving device.

[0087] The control server 20a controls the installation angle of the reflector 45 and the reflection power of each of the reflection power change RIS 46 by controlling the installation angle control device 21a and the reflection power control device 24, and generates a desired propagation channel from the transmission device 40 (S214). That is, the radio wave propagation environment reproduction system 10a reproduces the radio wave propagation environment.

[0088] The receiving device replaced from the arrival direction estimation device 44 receives the radio wave. Then, for example, the control server 20a performs evaluation of the propagation characteristics of the radio wave received by the receiving device (S216).

[0089] In this way, the radio wave propagation environment reproduction system 10a can easily reproduce a more complex propagation channel such as when the radio wave arrives only from a certain direction by changing the installation angle of the reflector 45 and the reflection power of each of the reflection power change RIS 46.

[0090] Note that each function of the radio wave propagation environment reproduction system 10 and the radio wave propagation environment reproduction system 10 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0091] For example, the control servers 20 and 20a can be realized using a computer and a program, and it is also possible to record the program on a storage medium or provide it through a network.

Explanation of Signs

[0092] 10, 10a... Radio wave propagation environment reproduction system, 20, 20a... Control server, 21, 21a... Installation angle control device, 22... Channel emulator, 23... Reflection angle control device, 24... Reflection power control device, 30, 30a... Reverberation chamber, 40... Transmission device, 41... Reflection angle change RIS, 42... Mounting table, 43... Radio wave absorber, 44... Arrival direction estimation device, 45... Reflector, 46... Reflection power change RIS

Claims

1. A transmitting device that transmits radio waves in a predetermined direction in an anechoic chamber, A reflection angle change RIS that reflects the radio waves transmitted by the transmitting device at an angle according to a control signal, An installation angle control device that controls the installation angle of the reflection angle change RIS by outputting a control signal to the reflection angle change RIS, A reflection angle control device that controls the reflection angle of the radio waves by the reflection angle change RIS by outputting a control signal to the reflection angle change RIS, An arrival direction estimation device that estimates the arrival direction of the radio waves reflected by the reflection angle change RIS at a predetermined position in the anechoic chamber, A control server that controls the installation angle control device and the reflection angle control device based on the arrival direction of the radio waves estimated by the arrival direction estimation device A radio wave propagation environment reproduction system characterized by comprising.

2. The transmitting device, Characterized by having an antenna with a half-value angle showing directivity that matches the line-of-sight range with respect to the reflection angle change RIS The radio wave propagation environment reproduction system according to claim 1.

3. A transmitting device that transmits radio waves in a predetermined direction in an anechoic chamber, A reflector that reflects the radio waves transmitted by the transmitting device, An installation angle control device that controls the installation angle of the reflector by outputting a control signal to the reflector, A reflection power change RIS that changes and reflects the radio waves reflected by the reflector to a power according to a control signal, A reflection power control device that controls the power of the radio waves reflected by the reflection power change RIS by outputting a control signal to the reflection power change RIS, An arrival direction estimation device that estimates the arrival direction of the radio waves reflected by the reflection power change RIS at a predetermined position in the anechoic chamber, A control server that controls the installation angle control device and the reflection power control device based on the arrival direction of the radio waves estimated by the arrival direction estimation device A radio wave propagation environment reproduction system characterized by comprising.

4. The transmitting device, Characterized by having an antenna with a half-value angle showing directivity that matches the line-of-sight range with respect to the reflector The radio wave propagation environment reproduction system according to claim 3.

5. A step of controlling the installation angle of a reflection angle change RIS that reflects radio waves transmitted by a transmitting device in a predetermined direction in an anechoic chamber at an angle according to a control signal, A step of controlling the reflection angle of the radio waves reflected by the reflection angle change RIS by a control signal, estimating the arrival direction of the radio wave reflected by the reflection angle-changing RIS at a predetermined position in the reverberation chamber; controlling the installation angle and the reflection angle of the reflection angle-changing RIS based on the estimated arrival direction of the radio wave; A radio wave propagation environment reproduction method, characterized by including the above steps.

6. The transmitting device has an antenna with a half-value angle showing directivity that matches the line-of-sight range with respect to the reflection angle-changing RIS. The radio wave propagation environment reproduction method according to claim 5, characterized by the above.

7. controlling the installation angle of a reflector that reflects the radio wave transmitted by the transmitting device in a predetermined direction in the reverberation chamber; controlling the reflected power of the radio wave reflected by the reflector with respect to a reflection power-changing RIS that changes and reflects the power according to a control signal; estimating the arrival direction of the radio wave reflected by the reflection power-changing RIS at a predetermined position in the reverberation chamber; controlling the installation angle of the reflector and the power of the radio wave reflected by the reflection power-changing RIS based on the estimated arrival direction of the radio wave; A radio wave propagation environment reproduction method, characterized by including the above steps.

8. The transmitting device has an antenna with a half-value angle showing directivity that matches the line-of-sight range with respect to the reflector. The radio wave propagation environment reproduction method according to claim 7, characterized by the above.

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