阅读说明：本技术 一种智能超表面的反射系数计算方法及系统 (Method and system for calculating reflection coefficient of intelligent super surface ) 是由 尹海帆 李展鹏 于 2021-01-04 设计创作，主要内容包括：本发明公开了一种智能超表面的反射系数计算方法及系统,属于无线通信技术领域,方法包括：为每个反射单元设置一个初始反射系数并激活RIS上所有反射单元；各个反射单元被激活后可以反射射向其的电磁信号；将所有反射单元进行分组,依次改变每一组反射单元的反射系数,并固定其余反射单元的反射系数,使RIS在不同反射系数的条件下进行扫描；通过比较用户设备(UE)反馈的数据,确定每一组反射单元的最优反射系数,由此得到反射系数矩阵。如此,本发明在保证时间复杂度低的前提下能有比较高的准确度；同时通过改变RIS反射单元的反射系数,使反射信号主波束指向用户方位,不需要移动用户的位置。(The invention discloses a method and a system for calculating a reflection coefficient of an intelligent super surface, belonging to the technical field of wireless communication, wherein the method comprises the following steps: setting an initial reflection coefficient for each reflection unit and activating all reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated; grouping all the reflection units, sequentially changing the reflection coefficient of each group of reflection units, and fixing the reflection coefficients of the rest reflection units to enable the RIS to scan under the condition of different reflection coefficients; and determining the optimal reflection coefficient of each group of reflection units by comparing data fed back by User Equipment (UE), thereby obtaining a reflection coefficient matrix. Therefore, the invention can have higher accuracy on the premise of ensuring low time complexity; meanwhile, the main beam of the reflected signal is enabled to point to the position of the user by changing the reflection coefficient of the RIS reflection unit, and the position of the user does not need to be moved.)

1. A method for calculating the reflection coefficient of an intelligent super surface is characterized by comprising the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating all reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping all the reflection units, changing the reflection coefficient of one group of the reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user;

(3) changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined.

2. A method for calculating the reflection coefficient of an intelligent super surface is characterized by comprising the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating a partial reflection unit on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping the rest reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining an optimal reflection coefficient of the first group of reflection units by comparing data fed back by a user;

(3) activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined.

3. A method as claimed in claim 1 or 2, characterized in that the reflection unit is activated by means of the application of a voltage signal or an optical signal or a pressure signal.

4. A method as claimed in claim 1 or 2, characterized in that the reflection coefficient of the reflection unit is changed by means of applying a voltage signal or an optical signal or a pressure signal.

5. The method of claim 1 or 2, wherein the data fed back by the user is an indicator of the received signal strength of the user, including CQI, SNR, SINR, RSRP, RSRQ, RSSI.

6. The method of claim 1 or 2, wherein the user performs a feedback after each scan, compared by the RIS; alternatively, the first and second electrodes may be,

and sending an instruction to the user by the RIS to instruct the user to continuously scan the RIS in the future K time sequences, comparing the acquired data by the user after the continuous scanning, determining the optimal reflection coefficient corresponding to the maximum received signal intensity, and feeding back the optimal reflection coefficient to the RIS.

7. An intelligent super-surface reflectance calculation system, comprising:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating all the reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping all the reflection units, changing the reflection coefficient of one group of the reflection units and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user; changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined.

8. An intelligent super-surface reflectance calculation system, comprising:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating the partial reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping the rest of the reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining an optimal reflection coefficient of the first group of reflection units by comparing data fed back by a user; activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined.

9. A system as claimed in claim 7 or 8, characterized in that the reflection unit is activated by means of the application of a voltage signal or an optical signal or a pressure signal.

10. The system of claim 7 or 8, wherein the user performs a feedback after each scan, compared by the RIS; alternatively, the first and second electrodes may be,

and sending an instruction to the user by the RIS to instruct the user to continuously scan the RIS in the future K time sequences, comparing the acquired data by the user after the continuous scanning, determining the optimal reflection coefficient corresponding to the maximum received signal intensity, and feeding back the optimal reflection coefficient to the RIS.

Technical Field

The invention belongs to the technical field of wireless communication, and particularly relates to a method and a system for calculating a reflection coefficient of an intelligent super surface.

Background

In the field of 5G wireless communication and even the field of future 6G wireless communication, the millimeter wave technology is extremely important as a key technology, but the millimeter wave has the fatal defect, and the loss is serious when the millimeter wave meets an obstacle, so that the communication effect is not ideal.

To solve this problem, the prior art adds a specially manufactured, low-cost, programmable Intelligent super Surface (RIS/Large Intelligent Surface/configurable Intelligent Surface/Software Defined Surface/measuring Surface/IRS/Intelligent reflection Surface/configurable metal-Surface/geographical MIMO, etc., hereinafter all expressed as RIS) to the wireless communication environment to assist communication. When there is a barrier between the AP (access point) or the Base Station (Base Station) and the User Equipment (UE), a signal may be reflected at the RIS by installing a RIS at a suitable position, so as to form a channel AP-RIS-UE, so that the AP and the UE can perform effective communication, as shown in fig. 1.

However, in most of the existing studies, the calculation of the RIS reflection coefficient matrix is implemented based on the radio Channel Information (CSI) of the AP-RIS or RIS-UE, and the complexity is at least O (N)²) Or higher. However, unlike the traditional Multiple Input Multiple Output (MIMO) technology, the RIS does not have a radio frequency link (RF-Chain) and cannot sense electromagnetic wave signals in the environment, so that the acquisition of the wireless channel information of the AP-RIS or RIS-UE is a difficult problem.

When the wireless channel information cannot be effectively acquired, the determination of the RIS reflection coefficient matrix can adopt an exhaustive search method. The exhaustive search method can find the optimal reflection coefficient (i.e. the phase shift and amplitude generated by the reflection unit), but the time complexity is too high, and if we quantize the reflection coefficient by n-bit and the number of the reflection units on the RIS is m, the time complexity is O (2)^m*n) If the number of reflection units is large, too high time complexity cannot adapt to a rapidly changing channel, and the practicability of the method is limited.

Therefore, in most of the realized RIS, there is no good method to autonomously adjust the position of the main lobe of the reflected signal so that the main beam with the strongest energy points to the user direction. In order to make the received signal strongest, the most conventional method is to adjust the position of the user to search the best receiving position, which obviously is troublesome and has great uncertainty.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides an intelligent super-surface reflection coefficient calculation method and system, so that the technical problems that the time complexity is too high or the performance cannot meet the requirements in the process of calculating the RIS reflection coefficient in the prior art are solved.

In order to achieve the above object, in one aspect, the present invention provides a method for calculating a reflection coefficient of an intelligent super-surface, including the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating all reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping all the reflection units, changing the reflection coefficient of one group of the reflection units, fixing the reflection coefficients of the other reflection units, and enabling the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user;

(3) changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined.

In another aspect, the present invention provides another method for calculating a reflection coefficient of an intelligent super-surface, comprising the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating a partial reflection unit on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping the rest reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the first group of reflection units by comparing data fed back by User Equipment (UE);

(3) activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined.

Further, the reflection unit is inactivated, which means that the reflection unit is in a substantially non-reflective state or a transmitted electromagnetic wave state.

Further, the reflection unit is activated by applying a voltage signal or an optical signal or a pressure signal.

Further, the reflection coefficient of the reflection unit is changed by applying a voltage signal or an optical signal or a pressure signal.

Further, the data fed back by the user is an indicator of the received signal strength of the user, including CQI, SNR, SINR, RSRP, RSRQ, and RSSI.

Further, the user performs a feedback after each scan, which is compared by the RIS; or, the RIS sends an instruction to the user to instruct the user to continuously scan the RIS in the future K time sequences, and after the continuous scanning, the user compares the acquired data to determine the optimal reflection coefficient corresponding to the maximum received signal intensity and feeds the optimal reflection coefficient back to the RIS.

In another aspect, the present invention provides a system for calculating a reflection coefficient of an intelligent super-surface, comprising:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating all the reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping all the reflection units, changing the reflection coefficient of one group of the reflection units, fixing the reflection coefficients of the other reflection units and enabling the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user; changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined.

In another aspect, the present invention provides another system for calculating a reflection coefficient of an intelligent super-surface, comprising:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating the partial reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping the rest of the reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining an optimal reflection coefficient of the first group of reflection units by comparing data fed back by a user; activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined.

Further, the reflection unit is inactivated, which means that the reflection unit is in a substantially non-reflective state or a transmitted electromagnetic wave state.

Further, the reflection unit is activated by applying a voltage signal or an optical signal or a pressure signal.

Further, the reflection coefficient of the reflection unit is changed by applying a voltage signal or an optical signal or a pressure signal.

Further, the data fed back by the user is an indicator of the received signal strength of the user, including CQI, SNR, SINR, RSRP, RSRQ, and RSSI.

Further, the user performs a feedback after each scan, which is compared by the RIS; or, the RIS sends an instruction to the user to instruct the user to continuously scan the RIS in the future K time sequences, and after the continuous scanning, the user compares the acquired data to determine the optimal reflection coefficient corresponding to the maximum received signal intensity and feeds the optimal reflection coefficient back to the RIS.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

(1) the invention uses the method of group iteration to change the reflection coefficient of each group of reflection units in turn, and fixes the reflection coefficients of the other reflection units, so that the RIS scans under the condition of different reflection coefficients; and determining the optimal reflection coefficient of each group of reflection units by comparing the data fed back by the user, thereby obtaining a reflection coefficient matrix. Therefore, the invention can have higher accuracy on the premise of ensuring low time complexity; meanwhile, the main beam of the reflected signal is enabled to point to the position of the user by changing the reflection coefficient of the RIS reflection unit, and the position of the user does not need to be moved.

(2) The method has strong universality, can be suitable for various RIS arrays such as square arrays, circular arrays and the like, has low time complexity of O (n) level and good performance, and has overall performance superior to that of a codebook exhaustive search method.

Drawings

Fig. 1 is a wireless communication system architecture diagram of an existing RIS;

FIG. 2 is a uniform rectangular area array model provided by the present invention;

FIG. 3 is a flow chart of a method for calculating a reflection coefficient of an intelligent super-surface according to the present invention;

FIG. 4 is a flow chart of another method for calculating the reflection coefficient of an intelligent super-surface provided by the present invention;

fig. 5-1 to 5-4 are a beam pattern under the optimal condition when not quantized, a beam pattern under the optimal condition when 1-bit is quantized, a beam pattern corresponding to the reflection coefficient calculated in the first mode, and a beam pattern corresponding to the reflection coefficient calculated in the second mode, respectively;

FIGS. 6-1 to 6-6 are beam patterns obtained by scanning under different reflection coefficients in a first manner, respectively;

7-1 to 7-11 are beam patterns obtained by scanning under different reflection coefficients in a second manner, respectively;

FIG. 8 shows an experimental setup and experimental environment according to the present invention;

FIG. 9-1 is a graph of actual measurements obtained using the above algorithm of the present invention to determine the reflection coefficient;

FIG. 9-2 shows the results of the measurement of the reflection coefficient of RIS as all-1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The plane array model researched by the invention consists of M × N structural units, wherein M is the row number of the reflection units in the RIS array, and N is the column number of the reflection units in the RIS array. As shown in fig. 2, the antenna elements in the y-axis and z-axis are uniformly arranged, d_yRepresenting the spacing between the elements of the y-axis, d_zRepresenting the spacing between the z-axis antenna elements.

In the working process of the RIS, in order to accurately align the reflected beam with the UE, we need to obtain a reflection coefficient matrix of the reflection unit to achieve the purpose of changing the electromagnetic reflection characteristics of the RIS. To avoid the extreme temporal complexity of exhaustive searches, we propose better performing search schemes, and for RIS of different initial states we propose the following two implementations:

the first method is as follows: referring to fig. 3, a flow chart of a method for calculating a reflection coefficient of an intelligent super surface provided by the invention includes the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating all reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping all the reflection units, changing the reflection coefficient of one group of the reflection units, fixing the reflection coefficients of the other reflection units, and enabling the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user;

(3) changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined, thereby obtaining the reflection coefficient matrix.

The second method comprises the following steps: referring to fig. 4, a flow chart of another method for calculating a reflection coefficient of an intelligent super-surface provided by the present invention includes the following steps:

(1) setting an initial reflection coefficient for each reflection unit and activating a partial reflection unit on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

(2) grouping the rest reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining an optimal reflection coefficient of the first group of reflection units by comparing data fed back by a user;

(3) activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user;

(4) and (4) repeating the step (3) until the whole reflection coefficient matrix is determined, thereby obtaining the reflection coefficient matrix.

Specifically, the reflection unit is activated by applying a voltage signal or an optical signal or a pressure signal.

Specifically, the data fed back by the user is an index of the received signal strength of the user, including

CQI, SNR, SINR, RSRP, RSRQ, RSSI, etc.

Specifically, the UE may perform feedback once after each scan, compared by the RIS. Or the RIS sends an instruction to the UE to inform the UE that the RIS can carry out continuous scanning in the future K time sequences, and after the continuous scanning, the UE compares and determines the optimal scanning beam and feeds back to inform the RIS which reflection coefficient matrix the signal is strongest.

Furthermore, based on the reflection coefficient of each reflection unit, the main beam of the reflection signal is enabled to point to the direction of the user by changing the reflection coefficient of the RIS reflection unit, and effective communication between the wireless AP and the user can be realized without changing the position of the user.

In another aspect, the present invention provides a system for calculating a reflection coefficient of an intelligent super-surface, comprising:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating all the reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping all the reflection units, changing the reflection coefficient of one group of the reflection units, fixing the reflection coefficients of the other reflection units and enabling the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the group of reflection units by comparing data fed back by a user; changing the reflection coefficient of the next group of reflection units, and fixing the reflection coefficients of the other reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined, the reflection coefficient matrix is obtained.

In another aspect, the present invention provides another system for calculating a reflection coefficient of an intelligent super-surface, including:

the initialization module is used for setting an initial reflection coefficient for each reflection unit and activating the partial reflection units on the RIS; each reflecting unit can reflect the electromagnetic signals emitted to the reflecting unit after being activated;

the optimal reflection coefficient determining module is used for grouping the rest of the reflection units, activating the first group of reflection units, and changing the reflection coefficient of the first group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining an optimal reflection coefficient of the first group of reflection units by comparing data fed back by a user; activating the next group of reflection units and changing the reflection coefficient of the next group of reflection units to enable the RIS to scan under the condition of different reflection coefficients; determining the optimal reflection coefficient of the next group of reflection units by comparing data fed back by a user; until the entire reflection coefficient matrix is determined, the reflection coefficient matrix is obtained.

The division of the modules in the reflection coefficient calculation system of the intelligent super surface is only used for illustration, and in other embodiments, the reflection coefficient calculation system of the intelligent super surface can be divided into different modules as required to complete all or part of the functions of the system.

The present invention is further described below in a specific application scenario.

1. Preconditions and associated presets

(1) There is a communication system composed of an AP, a UE, and a RIS. The relevant parameters of AP and RIS are known, including the distribution of RIS reflecting units, etc.

(2) The size of the RIS reflection array is M × N, and the intervals of the reflection units are respectively D_y、D_z。

(3) The reflection coefficient of the reflection unit has n-bit quantization.

2. The concrete steps

(1) Setting a model initial value: frequency, velocity, wavelength, reflective element spacing, initial pitch angle, and azimuth angle.

(2) All the reflecting units are in working state, and optionally, part of the reflecting units can also be in working state.

(3) And grouping the reflection units, selecting one group as a reference group, and selecting the optimal solution under the current condition in each iteration.

(4) Beam scanning: when beam scanning is carried out, the receiving antenna needs to feed back corresponding data to the RIS controller in time after receiving signals.

3. Setting simulation parameters

RIS: the number of rows N is 20, the number of columns M is 40, the total number of the reflection units is 800, each column has 4 control units, and each control unit controls 5 reflection units; reflection sheetElement spacing d_z＝d_y＝0.262λ。

Spatial position: establishing a coordinate system by taking the lower left corner unit of the RIS as a coordinate origin (0, 0, 0), wherein the RIS is positioned on a yoz plane, the reflecting units in the y direction and the z direction are uniformly distributed, and the distance is D_yAnd D_z。

Emission source: frequency f is 5.5GHz and wave speed v is 3 × 10⁸m/s, normal incidence.

Far field model: plane waves arrive at the RIS.

A receiving antenna: lying in the xoy plane, the azimuth angle is 45 °.

Grouping: one column is divided into a group, the reflection coefficient of each column of reflection units is consistent, and only one row of reflection units has the change of the reflection coefficient as an example.

And (3) quantification: for each reflection coefficient q_n,nA 1-bit quantization is performed.

Reflection coefficient amplitude | qn_,n|＝1。

The channel amplitude a is 1.

4. Simulation result

The best case is calculated from the known UE pitch and azimuth angles, in which case the RIS can provide the maximum gain.

Fig. 5-1 to 5-4 show a beam pattern in the optimal case without quantization, a beam pattern in the optimal case with 1-bit quantization, a beam pattern corresponding to the reflection coefficient calculated in the first mode, and a beam pattern corresponding to the reflection coefficient calculated in the second mode.

(1) In a first mode

(11) RIS initial example reflection coefficient matrixThe scan back view is shown in fig. 6-1.

(12) Taking the first row of the reflecting units as a reference group, changing the reflection coefficient of the second row of the reflecting units into 180 degrees, and changing the example intoThe scanning backward direction is shown in FIG. 6-2; after comparisonThe phase shift of the reflective elements of the second column is determined to be 0.

(13) The phase shift of the third column of reflective elements is changed to 180 deg., and the example becomesThe scanning backward direction is shown in fig. 6-3; the phase shift of the third column of reflective elements is determined to be 180 deg. after the comparison.

(14) The fourth column of reflective elements is phase shifted to 180 deg., the example becomesThe scanning backward direction is shown in fig. 6-4; the phase shift of the reflecting elements of the fourth column is determined to be 180 deg. after the comparison.

(15) Iterating through column 20, the example is:

[1,1, -1, -1,1,1, -1, -1, -1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1.

(16) When the iteration is complete, examples are:

[1,1, -1, -1,1,1, -1, -1, -1,1,1,1, -1, -1, -1,1,1, -1, -1,1,1,1] the scanning rear view is shown in FIGS. 6-6.

(2) Mode two

(21) The reference codeword is [1], examples of the first iteration are [1,1], [1, -1], and the corresponding patterns after scanning are shown in fig. 7-1 and 7-2.

(22) After the first iteration, the exemplary codeword is determined as [1,1], and the second iteration is exemplary as [1,1,1], [1,1, -1], and the corresponding directional patterns after scanning are shown in fig. 7-3 and 7-4.

(23) After the second iteration, the exemplary codeword is determined to be [1,1, -1], and the third iteration is exemplary of [1,1, -1,1], [1,1, -1,1], and the corresponding patterns after scanning are shown in fig. 7-5 and 7-6.

(24) After a third iteration the exemplary codeword is determined to be [1,1, -1, -1], and after a fourth iteration the exemplary codeword is determined to be [1,1, -1, -1,1], [1,1, -1, -1, -1], and after scanning the corresponding patterns are shown in fig. 7-7 and 7-8.

(25) An example codeword at the nineteenth iteration is:

[1,1,-1,-1,-1,1,1,1,-1,-1,1,1,1,-1,-1,-1,1,1,-1,1]，

[1,1, -1, -1, -1,1,1,1, -1, -1,1,1,1, -1, -1, -1,1,1, -1, -1], the corresponding patterns after scanning are shown in FIGS. 7-9 and 7-10.

(26) When the iteration is complete, examples are:

[1,1, -1, -1,1,1,1, -1, -1,1,1,1, -1, -1, -1,1,1, -1, -1, -1,1,1,1, -1, -1,1,1,1], the corresponding pattern after scanning is shown in FIGS. 7-11.

5. Actual measurement result

Spatial position: the user is coplanar with the RIS and is at 30 degrees of the RIS

The following are the actual measurement results in the microwave darkroom environment (as shown in fig. 8, the experimental apparatus and experimental environment of the present invention) based on the above algorithm:

FIG. 9-1 is a graph of actual measurements obtained using the above algorithm of the present invention to determine the reflection coefficient; FIG. 9-2 shows the results of the measurement of the reflection coefficient of RIS as all-1.

Therefore, the invention has higher accuracy on the premise of ensuring low time complexity.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.