Intelligent metasurface three-dimensional layered beam scanning method

Abstract

The invention provides an intelligent metasurface three-dimensional layered wave beam scanning method, and relates to the technical field of wireless communication, and the method comprises the steps: designing a phase offset matrix according to code words in an intelligent metasurface layered codebook, generating an intelligent metasurface wave beam, and according to the selection of the code words in the intelligent metasurface layered codebook, carrying out the scanning of the intelligent metasurface three-dimensional layered wave beam. Changing the direction and width of the intelligent metasurface beam; intelligent metasurface three-dimensional layered beam training is carried out on the coverage area, so that the intelligent metasurface beam width becomes narrower, rapid beam alignment is carried out on the optimal beam direction, and a beam training result is obtained; and performing beam refining on the beam training result to obtain a final beam scanning result. With the adoption of the scheme, rapid layered beam scanning of the intelligent metasurface on a three-dimensional space is realized.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a method and device for three-dimensional layered beam scanning of an intelligent metasurface. Background Art

[0002] Smart metasurface is an emerging technology applied to wireless communication networks. Smart metasurface is a digitally controllable metasurface composed of a large number of low-cost reflective array elements. By dynamically controlling the phase of the incident signal to reconstruct the wireless propagation environment, smart metasurface can transform the traditional design paradigm centered on passive adaptation to the wireless environment into a design paradigm centered on active intelligent shaping of the environment. This new paradigm will help to comprehensively improve the communication and perception capabilities of wireless communication networks.

[0003] At present, smart metasurfaces have been widely studied for use in the fields of communication and perception. In the field of communication, the active shaping of wireless channels by smart metasurfaces can break through the channel capacity in passive environments and significantly improve communication performance. In the field of perception, the use of smart metasurface beamforming to create a favorable electromagnetic environment for target perception can significantly improve perception performance. Based on the advantages of smart metasurface beamforming in improving communication and perception performance, related technologies have included smart metasurface beamforming methods based on channel estimation and smart metasurface beam scanning methods based on codebooks.

[0004] However, on the one hand, the number of smart metasurface elements is huge, and the smart metasurface beamforming method based on channel estimation has the problems of large feedback overhead and high beamforming complexity due to high-dimensional cascade channel estimation. On the other hand, for stereoscopic coverage scenarios, the traditional method of generating narrow beams based on codebooks to scan the coverage area has huge beam scanning overhead. Summary of the invention

[0005] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0006] To this end, the first purpose of the present application is to propose a three-dimensional layered beam scanning method for an intelligent metasurface, which solves the problem of high overhead of intelligent metasurface beamforming in existing methods, realizes rapid layered beam scanning of three-dimensional space by the intelligent metasurface, and effectively reduces the overhead of intelligent metasurface beamforming.

[0007] The second purpose of this application is to propose a smart metasurface.

[0008] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a three-dimensional layered beam scanning method for an intelligent metasurface, comprising:

[0009] A phase offset matrix is ​​designed according to the codewords in the smart metasurface hierarchical codebook to generate a smart metasurface beam, and the direction and width of the smart metasurface beam are changed according to the selection of the codewords in the smart metasurface hierarchical codebook;

[0010] Conduct three-dimensional layered beam training of the intelligent metasurface in the coverage area, so that the beam width of the intelligent metasurface becomes narrower, and fast beam alignment is achieved for the optimal beam direction to obtain beam training results;

[0011] The beam training results are refined to obtain the final beam scanning results.

[0012] Optionally, in one embodiment of the present application, the smart metasurface is configured with M y ×M z Array elements, M y With M z Respectively represent the number of smart metasurface elements along the y-axis and z-axis directions, M y =M z =M.

[0013] Optionally, in one embodiment of the present application, the intelligent metasurface hierarchical codebook includes K layers, K=log2M, and the kth layer includes 4 k codewords, the kth layer's (i k ,j k ) codewords are

[0014] Optionally, in one embodiment of the present application, a method for designing codewords in a smart metasurface hierarchical codebook includes:

[0015] If k = K, the codeword Designed for:

[0016]

[0017] Among them, b I The array response matrix representing the smart metasurface is expressed as:

[0018]

[0019] in, represents the Kronecker product, and the superscript T represents the transpose operation;

[0020] If k∈{1,...,K-1}, and l=Kk is an even number, the codeword Designed for:

[0021]

[0022] in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an even number, respectively, and are expressed as:

[0023]

[0024] in, The beam compensation value designed to reduce beam fluctuation, ζ e,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an even number, s∈{1,...,S e,l},S e,l =2 l / 2 ,

[0025]

[0026] in, The subarray response vector a is:

[0027] a(N,ψ)=[1,...,e jπ(n-1)ψ ,...,e jπ(N-1)ψ ] T

[0028] If k∈{1,...,K-1}, and l=Kk is an odd number, the codeword Designed for:

[0029]

[0030] in, is the main beamforming vector, ε is the auxiliary beamforming vector,

[0031]

[0032] The main beamforming vector is:

[0033]

[0034] in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an odd number, respectively, and are expressed as:

[0035]

[0036] in, The beam compensation value designed to reduce beam fluctuation, ζ o,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an odd number, s∈{1,...,S o,l},

[0037]

[0038] in,

[0039] Optionally, in one embodiment of the present application, the three-dimensional hierarchical beam training of the intelligent metasurface includes K stages, each stage includes 4 training beams; in the first stage, N training beams are formed in sequence based on the 4 codewords of the first layer of the intelligent metasurface hierarchical codebook to scan the entire coverage range; in the kth stage, the training beam with the best feedback in the k-1th stage is selected, and its coverage range is divided into 4 parts, and 4 training beams are formed in sequence based on the codewords of the kth layer of the intelligent metasurface hierarchical codebook to cover the 4 parts; in the Kth stage, the training beam with the best feedback in the K-1th stage is selected as the beam training result, and the corresponding codeword is recorded as

[0040] Optionally, in one embodiment of the present application, performing beam refinement on the beam includes:

[0041] According to the codewords in the intelligent metasurface hierarchical codebook Generate four scanning beams in sequence to scan the coverage area;

[0042] Calculate the intelligent metasurface beam refinement result, expressed as:

[0043]

[0044] Among them, i BR With j BR is the beam refinement index, expressed as:

[0045]

[0046] in, Indicates that the smart metasurface follows the codeword The feedback value received when generating a beam.

[0047] To achieve the above objectives, a second embodiment of the present invention proposes an intelligent metasurface, which adopts the above-mentioned intelligent metasurface three-dimensional layered beam scanning method to realize three-dimensional beam scanning.

[0048] Optionally, in one embodiment of the present application, the smart metasurface is configured with M y ×M z Array elements, M yWith M z Respectively represent the number of smart metasurface elements along the y-axis and z-axis directions, M y =M z =M.

[0049] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0051] Figure 1 A schematic diagram of a flow chart of a three-dimensional layered beam scanning method for an intelligent metasurface provided in Example 1 of the present application;

[0052] Figure 2 This is a schematic diagram of the application of the intelligent metasurface three-dimensional layered beam scanning method according to an embodiment of the present application;

[0053] Figure 3 A schematic diagram of a hierarchical codebook of an intelligent metasurface according to an embodiment of the present application;

[0054] Figure 4 A schematic diagram of three-dimensional layered beam training of an intelligent metasurface according to an embodiment of the present application;

[0055] Figure 5 A comparison diagram of beam scanning overheads between three-dimensional layered beam scanning and exhaustive beam scanning of the smart metasurface according to an embodiment of the present application;

[0056] Figure 6 This is a comparison chart of the beam alignment performance of the smart metasurface three-dimensional layered beam scanning and the exhaustive beam scanning according to the embodiment of the present application. DETAILED DESCRIPTION

[0057] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0058] The following describes the intelligent metasurface three-dimensional layered beam scanning method and device of the embodiments of the present application with reference to the accompanying drawings.

[0059] Figure 1 A schematic flow chart of a three-dimensional layered beam scanning method for an intelligent metasurface provided in Example 1 of the present application.

[0060] like Figure 1As shown, the intelligent metasurface three-dimensional layered beam scanning method comprises the following steps:

[0061] Step 101, designing a phase offset matrix according to the codewords in the smart metasurface hierarchical codebook, generating a smart metasurface beam, and changing the direction and width of the smart metasurface beam according to the selection of the codewords in the smart metasurface hierarchical codebook;

[0062] In this embodiment, if Figure 2 As shown in the figure, the intelligent metasurface assists the base station in direction finding of targets in blind spots through three-dimensional layered beam scanning.

[0063] In this embodiment, the number of base station antennas is set to 32, the number of smart metasurface array elements is set to 64×64, the distance from the base station to the smart metasurface is 40 meters, and the distance from the target to the smart metasurface is 10 meters.

[0064] Step 102, performing three-dimensional layered beam training of the intelligent metasurface on the coverage area, so that the beam width of the intelligent metasurface is narrowed from wide, and fast beam alignment is achieved for the optimal beam direction, and a beam training result is obtained;

[0065] Step 103: perform beam refinement on the beam training result to obtain the final beam scanning result.

[0066] Optionally, in one embodiment of the present application, the smart metasurface is configured with M y ×M z Array elements, M y With M z Respectively represent the number of smart metasurface elements along the y-axis and z-axis directions, M y =M z =M and its value is a power of 2.

[0067] Optionally, in one embodiment of the present application, Figure 3 As shown, the intelligent super surface layered codebook contains K = log2M layers, and the kth layer contains 4 k codewords, the kth layer's (i k ,j k ) codewords are

[0068] Optionally, in one embodiment of the present application, a method for designing codewords in a smart metasurface hierarchical codebook includes:

[0069] If k = K, the codeword Designed for:

[0070]

[0071] Among them, b IThe array response matrix representing the smart metasurface is expressed as:

[0072]

[0073] in, represents the Kronecker product, and the superscript T represents the transpose operation;

[0074] If k∈{1,...,K-1}, and l=Kk is an even number, the codeword Designed for:

[0075]

[0076] in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an even number, respectively, and are expressed as:

[0077]

[0078] in, The beam compensation value designed to reduce beam fluctuation, ζ e,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an even number, s∈{1,...,S e,l},S e,l =2 l / 2 ,

[0079]

[0080] in, The subarray response vector a is:

[0081] a(N,ψ)=[1,...,e jπ(n-1)ψ ,...,e jπ(N-1)ψ ] T

[0082] If k∈{1,...,K-1}, and l=Kk is an odd number, the codeword Designed for:

[0083]

[0084] in, is the main beamforming vector, ε is the auxiliary beamforming vector,

[0085]

[0086] The main beamforming vector is:

[0087]

[0088] in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an odd number, respectively, and are expressed as:

[0089]

[0090] in, The beam compensation value designed to reduce beam fluctuation, ζ o,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an odd number, s∈{1,...,S o,l},

[0091]

[0092]

[0093] in,

[0094] Optionally, in one embodiment of the present application, Figure 4 As shown in FIG. 1 , the three-dimensional hierarchical beam training of the smart metasurface includes K stages, each of which includes 4 training beams. In the first stage, N training beams are formed in sequence based on the 4 codewords of the first layer of the smart metasurface hierarchical codebook to scan the entire coverage range. In the kth stage, the training beam with the best feedback in the k-1th stage is selected, and its coverage range is divided into 4 parts. Four training beams are formed in sequence based on the codewords of the kth layer of the smart metasurface hierarchical codebook to cover the 4 parts. In the Kth stage, the training beam with the best feedback in the K-1th stage is selected as the beam training result, and the corresponding codeword is recorded as

[0095] Optionally, in one embodiment of the present application, beam refinement is performed on the beam to further improve the beam alignment accuracy, including:

[0096] According to the codewords in the intelligent metasurface hierarchical codebook Generate four scanning beams in sequence to scan the coverage area;

[0097] Calculate the intelligent metasurface beam refinement result, expressed as:

[0098]

[0099] Among them, i BR With j BRis the beam refinement index, expressed as:

[0100]

[0101] in, Indicates that the smart metasurface follows the codeword The feedback value received when generating a beam.

[0102] Figure 5 This is a comparison chart of the beam scanning overhead of the smart metasurface three-dimensional layered beam scanning method and the exhaustive beam scanning method in the embodiment of the present application. Figure 6 This is a comparison of the beam alignment performance of the smart metasurface three-dimensional layered beam scanning method and the exhaustive beam scanning method in the embodiments of the present application.

[0103] It should be noted that based on the above calculation and combined with Figure 5 and Figure 6 , we can draw the following conclusions, such as Figure 5 As shown in Figure 2, the beam training overhead of the proposed smart metasurface hierarchical beam scanning method is significantly lower than that of the exhaustive beam scanning method, and the overhead advantage is further expanded as the number of smart metasurface elements increases. This is because the beam training overhead of the hierarchical beam scanning method is logarithmically related to the number of smart metasurface elements, while the beam training overhead of the exhaustive beam scanning method is linearly related to the number of smart metasurface elements. In addition, the beam training overhead increased by beam refinement is almost negligible. And, as Figure 6 As shown in the figure, when the number of smart metasurface elements is small, the performance of the layered beam scanning method is not as good as the exhaustive beam scanning method, because the gain of beamforming is insufficient in the initial stage of layered beam scanning. However, as the number of smart metasurface elements increases, the performance of the proposed layered beam scanning method gradually surpasses the exhaustive beam scanning method, because the proposed beam refinement process can achieve super-resolution beam alignment. In addition, the results show that the performance of the layered beam scanning method will deteriorate if there is a lack of beam refinement or beam compensation process, which shows the necessity of beam refinement and beam compensation process.

[0104] Based on this, the intelligent metasurface three-dimensional layered beam scanning method proposed in this embodiment can significantly reduce the intelligent metasurface beam scanning overhead and can achieve performance higher than the traditional exhaustive beam scanning method.

[0105] In order to implement the above-mentioned embodiments, the present application also proposes a smart metasurface three-dimensional layered beam scanning device, which adopts the above-mentioned smart metasurface three-dimensional layered beam scanning method to realize three-dimensional beam scanning.

[0106] It should be noted that the aforementioned explanation of the embodiment of the intelligent metasurface three-dimensional layered beam scanning method is also applicable to the intelligent metasurface three-dimensional layered beam scanning device of this embodiment, and will not be repeated here.

[0107] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0108] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0109] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0110] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0111] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0112] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0113] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0114] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A three-dimensional layered beam scanning method for an intelligent metasurface, characterized in that: include: A phase offset matrix is ​​designed according to the codewords in the smart metasurface hierarchical codebook to generate a smart metasurface beam, and the direction and width of the smart metasurface beam are changed according to the selection of the codewords in the smart metasurface hierarchical codebook; Conduct three-dimensional layered beam training of the intelligent metasurface in the coverage area, so that the beam width of the intelligent metasurface becomes narrower, and fast beam alignment is achieved for the optimal beam direction to obtain beam training results; The beam training result is subjected to beam refinement to obtain a final beam scanning result.

2. The method according to claim 1, characterized in that The smart metasurface is configured with M y ×M z Array elements, M y With M z Respectively represent the number of smart metasurface elements along the y-axis and z-axis directions, M y =M z =M.

3. The method according to claim 2, characterized in that The intelligent super surface hierarchical codebook includes K layers, K=log2M, and the kth layer includes 4 k codewords, the kth layer's (i k ,j k ) codewords are 4. The method according to claim 3, characterized in that The method for designing codewords in the intelligent metasurface hierarchical codebook comprises: If k = K, the codeword Designed for: Among them, b I The array response matrix representing the smart metasurface is expressed as: in, represents the Kronecker product, and the superscript T represents the transpose operation; If k∈{1,...,k-1}, and l=Kk is an even number, the codeword Designed for: in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an even number, respectively, and are expressed as: in, The beam compensation value designed to reduce beam fluctuation, ζ e,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an even number, s∈{1,...,S e,l },S e,l =2 l / 2 , in, The subarray response vector a is: a(N,ψ)=[1,…,e jπ(n - 1)ψ ,...,and jπ(N - 1)ψ ] T If k∈{1,...,K-1}, and l=Kk is an odd number, the codeword Designed for: in, is the main beamforming vector, ε is the auxiliary beamforming vector, The main beamforming vector is: in, and They represent the horizontal beamforming vector and the vertical beamforming vector when l is an odd number, respectively, and are expressed as: in, The beam compensation value designed to reduce beam fluctuation, ζ o,l is the beam compensation coefficient, and They represent the sth horizontal beamforming subvector and vertical beamforming subvector when l is an odd number, s∈{1,...,S o,l }, in, 5. The method according to claim 4, characterized in that The intelligent metasurface three-dimensional hierarchical beam training includes K stages, each stage includes 4 training beams; in the first stage, N training beams are formed in sequence based on the 4 codewords of the first layer of the intelligent metasurface hierarchical codebook to scan the entire coverage area; In the kth stage, the training beam with the best feedback in the k-1th stage is selected, and its coverage is divided into 4 parts, and 4 training beams are sequentially formed based on the codewords of the kth layer of the intelligent metasurface hierarchical codebook to cover the 4 parts; In the Kth stage, the optimal training beam fed back in the K-1th stage is selected as the beam training result, and the corresponding codeword is recorded as 6. The method according to claim 5, characterized in that Perform beam refinement on the beam, including: According to the codewords in the intelligent metasurface hierarchical codebook Generate four scanning beams in sequence to scan the coverage area; Calculate the intelligent metasurface beam refinement result, expressed as: Among them, i BR With j BR is the beam refinement index, expressed as: in, Indicates that the smart metasurface follows the codeword The feedback value received when generating a beam.

7. A smart metasurface, characterized in that: The smart supersurface adopts the smart supersurface three-dimensional layered beam scanning method as described in claim 1 to achieve three-dimensional beam scanning.

8. The smart supersurface according to claim 7, characterized in that: The smart metasurface is configured with M y ×M z Array elements, M y With M z Respectively represent the number of smart metasurface elements along the y-axis and z-axis directions, M y =M z =M.

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