Intelligent ultra-surface wave arrival angle estimation method and device

Abstract

The invention provides an intelligent super surface wave angle of arrival estimation method and device, and the method comprises the steps: dividing a search space into a plurality of grids, and enabling each grid to correspond to a codebook; traversing all codebooks by using an intelligent metasurface array, and counting power information reported by a receiving end; screening maximum power information in the power information, and determining a preliminary direction of arrival according to the maximum power information; dividing the intelligent metasurface array into a plurality of sub-arrays, and performing phase assignment on each array of the sub-arrays based on the initial direction of arrival; and calculating the direction of arrival according to the assigned phase value of each oscillator. According to the invention, the problem of inaccurate array phase acquisition of the RIS under the condition of weak coverage is effectively solved, and high-precision DOA estimation of the RIS is realized.

Description

Technical Field

[0001] The present application belongs to the field of wireless communications, and specifically relates to an intelligent metasurface angle of arrival estimation method and device. Background Art

[0002] In recent years, with the gradual maturity of the fifth generation mobile communication system (5G) and the gradual advancement of the next generation mobile communication network (6G), the future mobile communication network is developing towards higher speed, lower latency and massive connections. Based on the rapid development of metamaterial technology, RIS (Reconfigurable Intelligent Surface) is expected to help achieve a fully controllable electromagnetic environment and has great potential in wireless communication and positioning systems above 5G. RIS is a planar array composed of a large number of low-cost, low-energy array units. Unlike symmetrical reflection based on the law of reflection, each unit that makes up RIS can apply an independent phase shift to the incident signal to achieve beamforming of the reflected (refracted) wave signal, thereby providing more degrees of freedom for the wireless transmission environment, which plays an important role in expanding coverage, alleviating path loss, and enhancing the signal strength at the receiving end.

[0003] RIS-based wireless networks are compatible with the standards and hardware of existing wireless networks, so RIS can be integrated into existing communication systems to achieve reliable and high-precision location estimation at low cost and high energy efficiency. At present, there are two common methods for DOA (Direction of Arrival) estimation based on RIS. The first is the beam scanning scheme, that is, by gridding the space, each beam direction corresponds to a codebook, and by traversing the preset codebook set, beam scanning in different directions can be achieved. Under each codebook, DOA estimation can be completed by collecting the power value reported by the terminal. The other is DOA estimation based on the array phase, that is, the phase information of the RIS array on the cascade channel is obtained in some way, and high-precision DOA algorithms such as MUSIC can be used to achieve high-precision DOA estimation. Compared with the former, the latter can break through the aperture limitation of RIS, thereby achieving higher estimation accuracy. However, in real networks, RIS is mostly deployed in weak coverage scenarios, and the energy of the signal reaching the terminal through the RIS cascade link is small, so it is difficult to accurately obtain the phase of each array on the RIS on the cascade channel, thereby achieving accurate DOA estimation. Summary of the invention

[0004] In order to solve the technical problem that it is difficult to accurately obtain the phase of each array on the RIS on the cascade channel in a weak coverage scenario, the present application proposes an intelligent metasurface angle of arrival estimation method and device.

[0005] In a first aspect, the present application proposes an intelligent metasurface angle of arrival estimation method, comprising: Divide the search space into several grids, each grid corresponds to a codebook; Use the smart metasurface array to traverse all codebooks and count the power information reported by the receiving end; Filtering maximum power information from the power information and determining a preliminary angle of arrival direction according to the maximum power information; The smart metasurface array is divided into multiple sub-arrays, and the phase of each element of the sub-array is assigned based on the preliminary wave arrival angle direction; The angle of arrival is calculated based on the phase values ​​of each array after assignment.

[0006] Optionally, the performing phase assignment on each array of the sub-array includes: Put the array on the i-th row and j-th column of the sub-array into phase; Traverse the K phase states of the sub-array, and in the kth phase state, obtain the phase value of the i-th row and j-th column of the sub-array.

[0007] Optionally, the multiple sub-arrays are evenly distributed, the sub-arrays include multiple arranged arrays, and the array manifold of the sub-arrays is a function related to the geometric center of the sub-arrays.

[0008] Optionally, in the process of traversing the phase states of each sub-array, the phase states of other arrays are kept unchanged.

[0009] Optionally, the step of calculating the angle of arrival according to the phase values ​​of each array after the assignment includes: Record the power information of the receiving end in the kth phase state; After collecting the power information of a preset number of phase states, the sub-array phase is estimated at the transmitting end using the obtained phase value of the array of the i-th row and j-th column of the sub-array; After X traversals, the phase values ​​of all sub-arrays on the smart metasurface array are solved; The angle of arrival is calculated by combining the phase values ​​of each sub-array and using the array arrival angle estimation algorithm.

[0010] Optionally, solving the angle of arrival by using an array arrival angle estimation algorithm includes: Combining the phase values ​​of each sub-array, the phase estimation frequency spectrum of the array and sub-array is obtained; The arrival angle of the receiving end to the smart metasurface array is determined by performing peak search on the frequency spectrum.

[0011] In the second aspect, an intelligent metasurface angle of arrival estimation device is proposed, comprising: The acquisition module is used to divide the search space into several grids, each grid corresponds to a codebook; the intelligent metasurface array is used to traverse all codebooks and count the power information reported by the receiving end; A determination module, used for screening the maximum power information in the power information and determining the preliminary wave arrival angle direction according to the maximum power information; and calculating the wave arrival angle according to the phase values ​​of each array after the assignment; The generation module is used to divide the smart metasurface array into multiple sub-arrays and assign phase values ​​to each array of the sub-array based on the preliminary wave arrival angle direction.

[0012] In a third aspect, a computer storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the intelligent metasurface angle of arrival estimation method described in the first aspect is implemented.

[0013] In a fourth aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the intelligent metasurface angle of arrival estimation method as described in the first aspect is implemented.

[0014] In a fifth aspect, the present application proposes a computer program product, including a computer program or instructions, which, when executed by a processor, implements the intelligent metasurface angle of arrival estimation method. Beneficial Effects The present application proposes an intelligent metasurface angle of arrival estimation method and device, which fully obtains the array gain of the subarray through pre-beam scanning combined with the idea of ​​subarray segmentation, effectively solves the problem of inaccurate array phase acquisition in RIS under weak coverage conditions, and realizes high-precision DOA estimation of RIS; secondly, the present application scheme can design the subarray shape and stepping scheme according to different needs, and has high flexibility; and in the process of subarray traversal, the stepping is performed by stepwise movement, so that there are cross-sections between the subarrays, which greatly reduces the accuracy loss caused by subarray segmentation; in the future 6G network, the intelligent metasurface device using the present application scheme has a very high application prospect of being widely deployed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of an intelligent metasurface angle of arrival estimation method according to an embodiment of the present application; Figure 2 This is a diagram showing the architecture of an angle estimation system based on a smart metasurface according to an embodiment of the present application; Figure 3 An example diagram of sub-array division and a stepping scheme in an embodiment of the present application; Figure 4 A schematic diagram of the phase estimation results of each array using single array estimation in an embodiment of the present application; Figure 5 A schematic diagram of phase estimation results of each sub-array using sub-array estimation in an embodiment of the present application; Figure 6 A two-dimensional search spectrum peak diagram estimated using a single array in an embodiment of the present application; Figure 7 A two-dimensional search spectrum peak diagram estimated using a subarray according to an embodiment of the present application; Figure 8 A principle block diagram of an intelligent metasurface angle of arrival estimation device according to an embodiment of the present application. DETAILED DESCRIPTION

[0016] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0017] In a certain implementation case, the topology architecture of the test device used in the present application scheme is as shown in the attached Figure 2 As shown, it includes 1 intelligent metasurface device, 1 signal transmitting end and 1 signal receiving end.

[0018] Obviously, the signal transmitting device is used to generate and transmit wireless signals, and can be an indoor base station, WiFi router, etc.

[0019] Assume that the RIS array contains RIS array. The RIS array has phase adjustment capability, and the phase states that can be adjusted are determined by the number of phase adjustment bits of the array. For example, for a RIS array with a phase adjustment capability of 2 bits, the phase states that can be adjusted are 0°, 90°, 180°, and 270°. Therefore, for the The phase of the array can be expressed as .

[0020] For DOA estimation, the most important thing is to obtain the phase of each array on the RIS array and estimate the angle of the incoming wave through a high-precision DOA estimation algorithm. Therefore, how to accurately obtain the phase of each array becomes the key. However, in real environments, the signal coverage of RIS deployment scenarios is weak, and the receiving end cannot accurately obtain the phase information of the received signal, which poses a great challenge to the acquisition of the RIS array phase.

[0021] The principle of solving this problem in the present application is as follows: first, traverse all codebooks of the intelligent metasurface, count the power information reported by the terminal in different codebook states, and determine the preliminary DOA direction based on the maximum power information reported by the terminal; then, divide the RIS into multiple evenly distributed subarrays, and for each subarray, assign phase values ​​to each array of the subarray based on the preliminary determined DOA direction, and align the gain of the subarray to the incoming wave direction; finally, based on methods such as the rotation vector method, estimate the phase information of all "transmitter-RIS subarray-receiver" wireless links, and implement DOA estimation based on a high-precision angle estimation algorithm.

[0022] The specific implementation of the present application is further described in detail below in conjunction with the drawings and examples.

[0023] Embodiment 1 On the first aspect, the present application provides an intelligent metasurface angle of arrival estimation method, which can accurately estimate the phase information of each subarray based on the pre-beam scanning + subarray segmentation method in a weak signal coverage scenario, thereby accurately estimating the signal arrival angle.

[0024] Specifically, Figure 1 As shown, the steps include: Step S1: Divide the search space into several grids, each grid corresponds to a codebook; For containing The RIS array of RIS arrays is assumed to contain Q codebooks. The spatial angle corresponding to the codebook is ,in is the horizontal angle, is the vertical angle.

[0025] Step S2: Use the smart metasurface array to traverse all codebooks and count the power information reported by the receiving end; Traverse all Q codebook information and count the received signal strength (i.e. signal power information) of the terminal (i.e. receiving end) under all codebooks: ; Among them, the intelligent metasurface is an array device based on metamaterial technology. The phase state of each array can be changed by programming. The terminal is used to receive wireless signals and report signal power information. It can be a smart terminal, smart wearable device, etc.

[0026] Step S3: Filter the maximum power information in the power information and determine the preliminary angle of arrival direction according to the maximum power information; The statistical results of screening step S2, the best codebook index is: …………………… (1) Based on the codebook, the direction of the incoming wave, that is, the direction of the angle of arrival, is preliminarily determined as: .

[0027] Step S4: Divide the smart metasurface array into multiple sub-arrays, and assign phase values ​​to each array of the sub-array based on the preliminary wave arrival angle direction; the steps are as follows: Step S4.1: put the array on the i-th row and j-th column of the sub-array into phase; Specifically, assuming that the adjacent array as a sub-array, then for the first sub-array, assuming that the array position of the i-th row and j-th column on the sub-array is , then the array manifold of this sub-array is: …………………… (2)

[0028]

[0029] in, is the wave arrival angle, k is the wave number, M is the number of arrays on one side of the square sub-array, is the array manifold of square subarrays, is the horizontal angle, is the vertical angle, is the geometric center of the subarray; It can be seen that the array manifold of the subarray is a function related to the geometric center of the array. That is, the subarray composed of adjacent M×M arrays can be regarded as a single array, the position of the array is the geometric center of the array, and the directional pattern of the array is the array manifold of the subarray; Put the array in the i-th row and j-th column of the subarray into phase: ……………… (3) in, is the preliminary angle direction vector determined based on step 1, To quantize the phase one of the, The number of preset phase states of the array (including 1, 2...k... K phase states), so the subarray can obtain The array gain of each array.

[0030] Step S4.2: Traverse the sub-array phase state, and in the kth phase state, obtain the phase value of the i-th row and j-th column of the sub-array.

[0031] Specifically, for the subarray in step S4.1, traverse phase state, keep other array states unchanged during the traversal process, in the kth phase state, the phase of the array in the i-th row and j-th column on the sub-array is: ……………… (4) Step S5: Calculate the angle of arrival according to the assigned phase values ​​of each array.

[0032] Specifically, the steps include: Step S5.1: Record the power information of the receiving end in the kth phase state; Specifically, the signal power information reported by the receiving end in the kth phase state of the subarray is recorded. For each channel state, the signal power information reported by the receiving end in the kth phase state of the subarray is recorded. The power information of the receiving end in each phase state is In WiFi and 5G communication networks, the receiving end will report the power information of its signal to the base station at a certain period. The network side can use this power reporting mechanism to obtain the power information of the receiving end; Step S5.2: after collecting the power information of a preset number of phase states, the sub-array phase is estimated at the transmitting end using the obtained phase value of the array of the i-th row and j-th column of the sub-array; Specifically, the transmitter collects all subarrays After the signal power information of the phase state is obtained, the sub-array phase is estimated; the specific method is as follows: for the receiving end power information , which can be expressed as: ……………………………… (5)

[0033] in, is the phase difference between the subarray and the remaining arrays, After removing this sub-array, the transmission coefficients of all remaining arrays in the entire RIS array from the transmitting end to the receiving end are: is the transmission coefficient from the transmitting end to the receiving end that only includes this subarray, is the phase of the kth phase state of the subarray.

[0034] From the above formula, we can know that It is actually the sum of three unknown quantities. The power information of each phase state can be obtained as follows: …………………… (6) Solving the above system of equations yields:

[0035] The phase difference between this subarray and the remaining arrays can be estimated as ; The above steps may also be solved by other methods, and the specific method is not limited.

[0036] Step S5.3: After a total of X traversals, the phase values ​​of all sub-arrays on the smart metasurface array are solved; Specifically, the traversal method is as follows Figure 3 As shown, traverse steps S5.1 to S5.2, after a total of The phase values ​​of all sub-arrays on all RIS arrays are solved by traversing the arrays.

[0037] Step S5.4: Combine the phase values ​​of each sub-array and use the array arrival angle estimation algorithm to solve the arrival angle. The steps are as follows: Step S5.4.1: Combining the phase values ​​of each sub-array, obtaining the phase estimation frequency spectrum of the array and the sub-array; like Figure 4 and Figure 5 They are phase values ​​estimated based on the array and the sub-array of M=3 on the RIS array with an array size of 11×11. It can be seen from the figure that when the sub-array-based method is used for estimation, the phase value is more accurate.

[0038] Step S5.4.2: Determine the angle of arrival of the receiving end to the smart metasurface array by performing a peak search on the frequency spectrum.

[0039] Figure 6 and Figure 7 In order to utilize the MUSIC algorithm, based on the spectrum estimated by the array and the M=3 subarray, the angle value of the receiving end to the RIS array can be determined by performing a peak search on the two-dimensional spectrum. It can be seen that the DOA estimation based on the array method has smaller side lobes and better effects.

[0040] The present application proposes an intelligent metasurface angle of arrival estimation method, which aims at multi-source angle of arrival estimation based on intelligent metasurface in complex environment, constructs multiple composite angle of arrival estimation signals based on intelligent metasurface, and comprehensively simulates multi-source angle of arrival estimation based on intelligent metasurface by generating and transmitting multiple composite angle of arrival estimation signals based on intelligent metasurface in real time, so as to provide a test basis for the target timing equipment to improve its resistance to angle of arrival estimation based on intelligent metasurface and time security performance.

[0041] Embodiment 2 This embodiment proposes an intelligent metasurface angle of arrival estimation device, such as Figure 8 As shown, including: The acquisition module is used to divide the search space into several grids, each grid corresponds to a codebook; the intelligent metasurface array is used to traverse all codebooks and count the power information reported by the receiving end; A determination module, used for screening the maximum power information in the power information and determining the preliminary wave arrival angle direction according to the maximum power information; and calculating the wave arrival angle according to the phase values ​​of each array after the assignment; The generation module is used to divide the smart metasurface array into multiple sub-arrays and assign phase values ​​to each array of the sub-array based on the preliminary wave arrival angle direction.

[0042] The intelligent metasurface angle of arrival estimation device provided in this embodiment has the same technical features as the intelligent metasurface angle of arrival estimation method provided in the first embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0043] Embodiment 3 The present application provides a computer storage medium on which a computer program is stored. When the program is executed by a processor, the intelligent metasurface angle of arrival estimation method of embodiment 1 is implemented.

[0044] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0045] Therefore, the present application also proposes a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the method described in any embodiment of the present application is implemented. The computer-readable storage medium can be configured in any device of the present application.

[0046] Embodiment 4 The present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the intelligent metasurface angle of arrival estimation method as described in Example 1 is implemented.

[0047] For example, it includes: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the method provided in the embodiment of the present application. The method is included in the above functional descriptions and will not be repeated here.

[0048] The electronic device also includes an input device and an output device; the processor, storage device, input device and output device in the electronic device can be connected via a bus or other means.

[0049] As a computer-readable storage medium, the storage device can be used to store software programs, computer executable programs and module units, such as program instructions corresponding to the method in the embodiment of the present application. The storage device may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, at least one application required for a function; the storage data area may store data created according to the use of the terminal, etc. In addition, the storage device may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some instances, the storage device may further include a memory remotely arranged relative to the processor, and these remote memories may be connected via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof. The various embodiments in the present application are described in a progressive manner, and the same and similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0050] Embodiment 5 This embodiment proposes a computer program product, including a computer program or instructions, which, when executed by a processor, implements the intelligent metasurface angle of arrival estimation method of embodiment 1.

[0051] Based on such understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a computer program product.

[0052] The various embodiments in the present application are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0053] The protection scope of the present application is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and modifications fall within the scope of the claims of the present disclosure and their equivalents, the intention of the present disclosure also includes these changes and modifications.

Claims

1. An intelligent metasurface angle of arrival estimation method, characterized in that: include: Divide the search space into several grids, each grid corresponds to a codebook; Use the smart metasurface array to traverse all codebooks and count the power information reported by the receiving end; Filtering maximum power information from the power information and determining a preliminary angle of arrival direction according to the maximum power information; The smart metasurface array is divided into multiple sub-arrays, and the phase of each element of the sub-array is assigned based on the preliminary wave arrival angle direction; The angle of arrival is calculated based on the phase values ​​of each array after assignment.

2. The intelligent metasurface angle of arrival estimation method according to claim 1, characterized in that: The phase assignment for each array of the sub-array includes: Put the array on the i-th row and j-th column of the sub-array into phase; Traversing the subarray phase state, and in the kth phase state, obtain the phase value of the i-th row and j-th column of the sub-array.

3. The intelligent metasurface angle of arrival estimation method according to claim 1, characterized in that: The multiple sub-arrays are evenly distributed, the sub-arrays include multiple arranged arrays, and the array manifold of the sub-arrays is a function related to the geometric center of the sub-arrays.

4. The intelligent metasurface angle of arrival estimation method according to claim 1, characterized in that: The phase assignment for each array of the sub-array includes: traversing the sub-array During the process of changing the phase state of one array, the phase state of other arrays remains unchanged.

5. The intelligent metasurface angle of arrival estimation method according to claim 1, characterized in that: The step of calculating the angle of arrival according to the phase values ​​of each array after the assignment includes: Record the power information of the receiving end in the kth phase state; After collecting the power information of a preset number of phase states, the sub-array phase is estimated at the transmitting end using the obtained phase value of the array of the i-th row and j-th column of the sub-array; After X traversals, the phase values ​​of all sub-arrays on the smart metasurface array are solved; The angle of arrival is calculated by combining the phase values ​​of each sub-array and using the array arrival angle estimation algorithm.

6. The intelligent metasurface angle of arrival estimation method according to claim 5, characterized in that: The method of using an array arrival angle estimation algorithm to solve the angle of arrival includes: Combining the phase values ​​of each sub-array, the phase estimation frequency spectrum of the array and sub-array is obtained; The arrival angle of the receiving end to the smart metasurface array is determined by performing peak search on the frequency spectrum.

7. An intelligent metasurface angle of arrival estimation device, used to implement the method described in any one of claims 1 to 6, characterized in that: include: An acquisition module is used to divide the search space into a number of grids, each grid corresponding to a codebook; Use the smart metasurface array to traverse all codebooks and count the power information reported by the receiving end; A determination module, used for screening the maximum power information in the power information and determining the preliminary wave arrival angle direction according to the maximum power information; and calculating the wave arrival angle according to the phase values ​​of each array after the assignment; The generation module is used to divide the smart metasurface array into multiple sub-arrays and assign phase values ​​to each array of the sub-array based on the preliminary wave arrival angle direction.

8. A computer storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the intelligent metasurface angle of arrival estimation method described in any one of claims 1 to 6 is implemented.

9. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for estimating the angle of arrival of the intelligent metasurface as claimed in any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the intelligent metasurface angle of arrival estimation method described in any one of claims 1 to 6 is implemented.

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