IRS control device, IRS control method and program

Abstract

An IRS control device according to the present invention comprises a storage unit that stores a radio wave map for a user of radio waves for a prescribed area for when an intelligent reflecting surface in the prescribed area has been set to a plurality of reflection coefficients, a reception unit that receives a requested map for the prescribed area as in a radio wave state requested by the user, an inference unit that infers an optimal reflection coefficient pattern for the IRS that satisfies the requested map on the basis of the radio wave map stored at the storage unit, and a reflection coefficient control unit that controls the reflection coefficients of the IRS to the optimal reflection coefficient pattern inferred by the inference unit.

Description

[Technical Field]

[0001] The present invention relates to an IRS control device, an IRS control method, and a program. This application claims priority to U.S. Provisional Patent Application No. 63 / 447,892, filed February 24, 2023, the contents of which are incorporated herein by reference. [Background technology]

[0002] Advances in transmission and reception technologies, such as antennas and access methods, have dramatically improved the performance of wireless communication technology. However, it is said that the growth of such wireless communication is gradually reaching its limits. One of the factors hindering this growth is the physical constraint that communication becomes unstable when there is an obstacle between the base station and the communication terminal. Intelligent Reflecting Surface (IRS) has attracted attention as a solution to this problem (see, for example, Patent Documents 1 to 5). IRS is an electromagnetic wave reflector composed of multiple passive reflecting elements. The reflecting elements are made of metamaterials whose properties can be dynamically changed. By appropriately changing the reflection properties of each element to design an ideal radio wave propagation path, it is possible to ensure a radio wave propagation route that bypasses obstacles, thereby realizing communication that is not affected by obstacles.

[0003] On the other hand, IRS requires a size of about 100 wavelengths of the carrier wave to ensure sufficient signal power through reflection. Therefore, if each telecommunications carrier installs its own communications infrastructure, there are concerns about the landscape and environmental damage caused by the increase in communications equipment and wiring. There are also concerns about economic impacts such as increased resource and energy consumption. Therefore, there is a demand for telecommunications carriers to improve the efficiency of communications infrastructure by sharing communications equipment such as IRS, thereby reducing the impact on the environment and economy.

[0004] However, it is not easy for each telecommunications carrier to share communication facilities. One method is to share base stations. This involves sharing the device that transmits from the base station, and this can be done by splitting the signals from each telecommunications carrier. In this case, the electrical signals from each carrier are input to the radiating antenna from the same antenna, and no communication control processing is performed in the shared section.

[0005] Another approach is to share an IRS. This involves sharing an IRS device and its control function. However, each carrier is assigned a different communication frequency, and current IRSs cannot set different phases for each frequency. Therefore, the control unit that controls the IRS must also be shared, and the IRS must be controlled to ensure radio wave conditions acceptable to each carrier. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2022 / 0216908 [Patent Document 2] International Publication No. 2021 / 207748 [Patent Document 3] US Patent Application Publication No. 2023 / 0047558 [Patent Document 4] US Patent Application Publication No. 2022 / 0216908 [Patent Document 5] European Patent Application Publication No. 4099574 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved is to provide good quality radio wave conditions to all users within a given area while sharing an IRS in a communication system. [Means for solving the problem]

[0008] One aspect of the present invention includes a storage unit that stores a radio wave map in a predetermined area of ​​a user who uses radio waves when an IRS (Intelligent Reflecting Surface) in the predetermined area is set with a plurality of reflection coefficients; a reception unit that receives a request map when the predetermined area becomes a radio wave state required by the user; an estimation unit that estimates an optimal reflection coefficient pattern of the IRS that satisfies the request map based on the radio wave map stored in the storage unit; and an IRS that calculates the optimal reflection coefficient pattern estimated by the estimation unit. RS and a reflection coefficient control unit that controls the reflection coefficient of the IRS control device. In other words, this IRS control device sets an IRS (Intelligent Reflecting Surface) within a specified area with multiple reflection coefficients, and is equipped with an estimation unit that estimates a reflection coefficient pattern of the IRS from the reflection coefficient patterns that can be set by the IRS to optimize the radio wave conditions of the multiple users overall, for the optimal radio wave conditions required by each of the multiple users of the IRS to which different communication frequencies are assigned within the specified area, and a reflection coefficient control unit that controls the multiple reflection coefficients of the IRS so that the reflection coefficient pattern estimated by the estimation unit is achieved. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide users within a predetermined area with good quality radio wave conditions while sharing an IRS in a communication system. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a configuration of a communication system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a configuration of an IRS control device. [Figure 3] 4 is a flowchart showing the operation of the IRS control device. [Figure 4] FIG. 1 is a diagram illustrating a configuration of an estimation model generating device. [Figure 5] 10 is a flowchart illustrating an operation of the estimation model generating device. [Figure 6] 10A and 10B are diagrams showing a measured radio wave map and an estimated radio wave map; [Figure 7] FIG. 10 is a diagram showing the communication capacity of a terminal when the number of MNOs is changed. [Figure 8] FIG. 10 is a diagram showing the communication capacity at a terminal when the number of terminals (users) is changed. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 is a diagram showing the configuration of a communication system 1 according to this embodiment. The communication system 1 includes a terminal 2, an MNO (Mobile Network Operator) 3, an IRS (intelligent reflecting surface) 4, and an IRS control device 5.

[0012] The multiple terminals 2 are terminals of users who receive communication services within a predetermined area controlled by the IRS 4, and communicate via base stations owned by the MNO 3. The terminals 2 are, for example, mobile phones, smartphones, personal computers, etc. The multiple terminals 2 may receive services from the same MNO 3 or from different MNOs.

[0013] There are multiple MNOs 3, and in this case, each MNO 3 is assigned a different communication frequency. Base stations owned by the MNO 3 relay communication data received from the terminal 2 to the IRS control device 5 or other networks. The MNO 3 includes, for example, a Radio Access Network (RAN) and a core network. The terminal 2 may connect to a different MNO 3 depending on radio wave conditions that are affected by its location, etc. The base station owned by the MNO 3 notifies the IRS control device 5 of a radio wave map (hereinafter referred to as a "request map") that requests that the communication environment of the terminal 2 be in a favorable state within a predetermined area controlled by the IRS 4. The radio wave map is a two-dimensional map that indicates the radio wave strength within a predetermined range. For example, the radio wave map is x ×J y It is shown by the matrix:

[0014] The request map is, for example, a diagram showing the current location of terminal 2 communicating with a base station owned by MNO 3 within a predetermined area controlled by IRS 4. For example, the request map shows whether a two-dimensional plane is divided into grids and whether terminal 2 is located in each grid. For example, the request map is a map where the element corresponding to the grid where terminal 2 is located is set to 1 and the other elements are set to 0. x ×J yThe request map notified by MNO3-u (u=1 to U) is hereinafter referred to as R u It is defined as:

[0015] IRS4 is a device that integrates metamaterial elements, which are minute structures that can freely control electromagnetic properties. IRS4 sets the reflection coefficient for each part of the device based on the state of radio waves within a specified area. The reflection coefficient is determined, for example, by setting the phase. Below, the reflection coefficient pattern of IRS4-c (c = 1 to C) is referred to as b c Reflection coefficient pattern b c is a vector indicating the parameters β and φ of the structures that make up, for example, IRS4. When there are N structures, the reflection coefficient pattern b c is b c ={φ x,1 , φ y,1 , β x,1 , β y,1 φ x,N , φ y,N , β x,N , β y,N}, where φ is the first order term of the reflection coefficient and β is the second order term of the reflection coefficient. In addition, all reflection coefficient patterns of IRS4 are defined as B={b1, . . . , b C} is defined as

[0016] 2 is a diagram showing the configuration of the IRS control device 5. The IRS control device 5 includes a reception unit 51, an estimation unit 52, a control unit 53, and a storage unit 54. The storage unit 54 stores an estimation model for estimating a radio wave map based on the reflection coefficient pattern of the IRS. The reception unit 51 receives required maps from a plurality of MNOs 3. The estimation unit 52 estimates a reflection coefficient pattern of the IRS 4 that satisfies the required maps of the plurality of MNOs 3, using an estimation model stored in the storage unit 54. A reflection coefficient pattern that satisfies the requirement map is, for example, a reflection coefficient pattern that maximizes the total value of the communication capacity of terminal 2 associated with all MNOs 3 within a predetermined area controlled by IRS 4. The communication capacity of terminal 2 is the communication capacity of the grid in which terminal 2 is located.

[0017] The method of the present invention will now be described in detail.

[0018] Each of the multiple MNOs 3 has a different communication frequency, and when IRS4 is set to a certain reflection coefficient, the radio wave map of each operator is different. A radio wave map for each MNO 3 when IRS4 is set to a certain reflection coefficient is calculated. The memory unit 54 learns an output model of the radio wave map when the MNO 3 sets IRS4 to a certain reflection coefficient, estimates a radio wave map when the MNO 3 sets IRS4 to a reflection coefficient not included in the learning data, and stores the learned output model of the radio wave map. The memory unit 54 is not limited to a storage medium such as a memory, but may also be a location where data can be stored, such as the cloud.

[0019] The IRS control device 5 searches for an IRS reflection coefficient pattern that satisfies the requirements of each MNO 3 in the estimation unit 52. Using the learned radio wave map of each MNO 3, reflection coefficient patterns that can be set by the IRS are collected from the storage unit 54.

[0020] Reflection coefficient pattern b c Based on this, we use an estimation model to estimate the radio wave map by MNO3-u (u=1~U). u Also, f u Estimated radio wave map X, which is the result of the estimation u ~(b) is defined by the following formula:

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[0021] The reception unit 51 receives a request map R from each MNO 3. u Then, the estimation unit 52 receives the estimation model f u and requirements map R u Based on this, the estimation unit 52 calculates an optimal reflection coefficient pattern B in which reflection coefficients that maximize the communication capacity of the entire system including MNO 3 are set. The estimation unit 52 calculates the optimal reflection coefficient pattern B by, for example, calculating equation (2).

number

[0022] Equation (2) calculates the communication capacity using the Shannon-Hartley theorem and calculates the reflection coefficient pattern B when the total communication capacity in each grid is maximized. The control unit 53 controls IRS4 to become the reflection coefficient pattern B so as to become the optimal reflection coefficient pattern estimated by the estimation unit 52.

[0023] By the control unit 53 controlling the IRS4 to have reflection coefficient pattern B, the ISR4 can provide high-quality radio wave conditions to all users, including terminals 2 with different MNOs 3, within a specified area controlled by the IRS4.

[0024] 3 is a flowchart showing the operation of the IRS control device 5. The reception unit 51 receives a request map R u (Step S101). The estimation unit 52 estimates the reflection coefficient pattern of IRS4 that satisfies the required map by using the learned radio wave map of each MNO3 stored in the storage unit 54 and the reflection coefficient pattern that can be set by the IRS, and estimates the reflection coefficient that maximizes the communication capacity of the entire system including MNO3 (Step S102). The control unit 53 controls the reflection coefficient pattern B of IRS4 so that it becomes the optimal reflection coefficient pattern estimated by the estimation unit 52 (Step S103).

[0025] The estimation unit 52 will be described in more detail below. The estimation model used by the estimation unit 52 is generated by an estimation model generation device 6. FIG. 4 is a diagram showing the configuration of the estimation model generation device 6. The estimation model generation device 6 includes a data acquisition unit 61, a learning unit 62, and an output unit 63. The estimation model generation device 6 may be included in the communication system 1.

[0026] The data acquisition unit 61 acquires data indicating the relationship between the reflection coefficient pattern of IRS4 and the learned radio wave maps including the radio wave maps not included in the learning data for each MNO3. (bi) u Data showing the relationship is prepared for each IRS4 and MNO3. The radio map may be converted to ground truth, for example, by equation (3).

number

[0027] where X max Radio Map X u ^ (bi) is the maximum value of the elements of

[0028] The data acquisition unit 61 acquires the estimated model f u The reflection coefficient pattern of IRS4 input to the estimated model f u The radio wave map in MNO3 output from the UE may be acquired. This increases the amount of data used for learning, which will be described later.

[0029] The learning unit 62 generates an estimation model f that estimates the radio wave map based on data showing the relationship between the reflection coefficient pattern of IRS4 and the radio wave map in MNO3. u The estimation model is, for example, a neural network, and estimates the radio wave map by a machine learning technique. The learning unit 62 updates the estimation model f u By inputting the reflection coefficient pattern b into the u ~(b) The learning unit 62 estimates the measured radio wave map X , which includes the measurement results of the actually measured radio wave map and the learned unknown radio wave map. u (b) and Estimated Radio Wave Map X u ~(b) The loss function between the two is calculated. The loss function is, for example, the mean squared error (MSE).

[0030] The learning unit 62 uses the measured radio wave map X u (b) and Estimated Radio Wave Map X u ~(b) In calculating the loss function between u (b) The learning unit 62 calculates the loss function only from the grids where the measured radio wave map X u (b) The map W is set to 1 for grids with a value of 1 and 0 for other grids. u Use X u (b) ·W u and X u ~(b) Calculate the loss function between

[0031] The learning unit 62 learns the estimated model f so that the calculated value of the loss function becomes smaller. u Update.

[0032] The output unit 63 outputs the updated estimation model f u is output to the IRS control device 5.

[0033] 5 is a flowchart showing the operation of the estimation model generating device 6. The data acquiring unit 61 acquires data showing the relationship between the reflection coefficient pattern of IRS4 and the radio wave map in MNO3 (step S201). The learning unit 62 generates an estimation model f that estimates the radio wave map based on the data showing the relationship between the reflection coefficient pattern of IRS4 and the radio wave map in MNO3. u (step S202). Then, the output unit 63 outputs the updated estimation model f u to the IRS control device 5 (step S203). The estimation model generation device 6 executes step S202 multiple times to generate the estimation model f u After updating multiple times, step S203 is performed to obtain the estimated model f u may be output.

[0034] (Example) This embodiment was examined using a simulation. The simulation was conducted in an actual area of ​​Sendai city, where a relatively large intersection was set up, with multiple MNOs having three base stations in surrounding buildings and roadside units, and five IRSs installed, simulating an environment with users inside the intersection and on the sidewalk. The size of the designated area was 48m 2 is.

[0035] Figure 6 shows the measured radio wave map X u (b) and Estimated Radio Wave Map X u ~(b) The measured radio wave map is a map converted to ground truth. The estimated model f u By measuring radio wave map X u (b) We were able to estimate a distribution close to this.

[0036] 7 and 8 show the results of comparing the method of this embodiment with other methods. The method being compared is a time-sharing method of ISR usage time that the inventors have considered as another ISR sharing method. In the time-sharing method, communication time is divided for each MNO 3, and the IRS 4 is controlled so that the total communication capacity of terminals 2 in each MNO 3 is maximized during each time period.

[0037] 7 is a diagram showing the communication capacity of terminal 2 when the number of MNOs 3 is changed. By increasing the number of MNOs 3, the improvement ratio of the communication capacity of the method (prop) of this embodiment to the communication capacity of the time division method (td) increases. Therefore, this embodiment is more advantageous when the number of MNOs 3 is large.

[0038] 8 is a diagram showing the communication capacity of terminal 2 (User) when the number of terminals 2 (Users) is changed. Even when the number of terminals 2 is changed, the communication capacity in the method of this embodiment is larger than the communication capacity in the time division method.

[0039] Other Embodiments One embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes and the like are possible within the scope that does not deviate from the gist of the present invention.

[0040] Estimation model f u However, the present invention is not limited to this. For example, the estimation model f u Alternatively, the estimation unit 52 may store data indicating the relationship between the reflection coefficient pattern of IRS4 and the radio wave map in MNO3, and output the corresponding radio wave map in MNO3 by selecting a reflection coefficient pattern to be stored. Even in this case, the estimation unit 52 can select the optimal reflection coefficient pattern B from the stored reflection coefficient patterns.

[0041] The IRS control device 5 and the estimation model generation device 6 in the above-described embodiments may be implemented in part or in whole by a computer. In this case, a program for implementing these functions may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Note that the term "computer system" as used herein includes an operating system (OS) and peripheral hardware. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or media that store programs for a fixed period of time, such as volatile memory within a computer system serving as a server or client. The programs may be programs for implementing some of the above-described functions, or may be programs that can be implemented in combination with programs already stored in the computer system. The IRS control device 5 and the estimation model generation device 6 may be implemented in part or in whole using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0042] The MNO 3 is not limited to a telecommunications carrier that is a user of the IRS 4, but may also be a user of the terminal 2 in a communication system that uses a different frequency band. Furthermore, each user may have a unique characteristic vector of the radio wave propagation environment. Furthermore, when a plurality of IRS4 exist within a predetermined area, control may be performed so that the reflection coefficient pattern maximizes the communication capacity of all the users calculated across all the IRS4. [Explanation of symbols]

[0043] 1 Communication system, 2 Terminal, 3 MNO, 4 IRS, 5 IRS control device, 51 Reception unit, 52 Estimation unit, 53 Control unit, 54 Memory unit, 6 Estimation model generation device, 61 Data acquisition unit, 62 Learning unit, 63 Output unit

Claims

1. a storage unit that stores, for each of a plurality of users, a radio wave map in a predetermined area of ​​a plurality of users using radio waves when an IRS (Intelligent Reflecting Surface) in the predetermined area is set with a plurality of reflection coefficients; a reception unit that receives a request map when the predetermined area has a radio wave condition that is requested by the plurality of users; an estimation unit that estimates an optimal reflection coefficient pattern of the IRS that satisfies the required map based on the radio wave map stored in the storage unit; an IRS control device comprising: a reflection coefficient control unit that controls the reflection coefficient of the IRS so as to obtain the optimal reflection coefficient pattern estimated by the estimation unit.

2. The optimal reflection coefficient pattern is a reflection coefficient pattern when the total value of all communication capacities of the users is maximized. The IRS control device of claim 1 .

3. The reflection coefficient is determined by setting the phase of the IRS. The IRS control device of claim 1 .

4. the estimation unit estimates the optimal reflection coefficient pattern using an estimation model learned by machine learning based on a radio wave map when the reflection coefficients stored in the storage unit are set. The IRS control device of claim 1 .

5. The estimation unit estimates, as the optimal reflection coefficient pattern, a reflection coefficient pattern that maximizes the communication capacity of all of the plurality of users. The IRS control device of claim 1 .

6. The plurality of users use different frequency bands. The IRS control device according to claim 5 .

7. storing a radio wave map for each of a plurality of users using radio waves in a predetermined area when the IRS in the predetermined area is set with a plurality of reflection coefficients; receiving a request map when the predetermined area has a radio wave condition required by the plurality of users; Estimating an optimal reflection coefficient pattern of the IRS that satisfies the requirement map based on the stored radio wave map; controlling the reflection coefficients of the IRS so as to obtain the estimated optimal reflection coefficient pattern; IRS control method.

8. A program for causing a computer to operate as the IRS control device according to any one of claims 1 to 6.

9. In an IRS control device that sets an IRS (Intelligent Reflecting Surface) within a predetermined area using a plurality of reflection coefficients, An estimation unit that estimates a reflection coefficient pattern of the IRS that optimizes the radio wave conditions of the plurality of users as a whole from reflection coefficient patterns that can be set by the IRS, for each optimal radio wave condition required by each of the plurality of users to which different communication frequencies are assigned within the predetermined area; a reflection coefficient control unit that controls the plurality of reflection coefficients of the IRS so as to achieve the reflection coefficient pattern estimated by the estimation unit.

10. In an IRS control method for setting an IRS (Intelligent Reflecting Surface) in a predetermined area using a plurality of reflection coefficients, In the predetermined area, for each of the optimal radio wave conditions required by a plurality of users of the IRS to which different communication frequencies are assigned, a reflection coefficient pattern of the IRS is estimated from the reflection coefficient patterns that can be set by the IRS, such that the radio wave conditions of the plurality of users are optimal overall; An IRS control method for controlling the plurality of reflection coefficients of the IRS so as to obtain the estimated reflection coefficient pattern.

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