Beam training method and device based on holographic metasurface

Abstract

The invention provides a beam training method and device based on a holographic metasurface, and the method comprises the steps: generating a multi-user angle domain codebook based on the parameter data of the holographic metasurface and preset angle domain codebook structure information; based on the multi-user angle domain codebook, performing angle domain beam scanning on a plurality of users in the signal coverage range of the holographic metasurface at the same time; generating a multi-user distance domain codebook based on an angle set of a plurality of users obtained by beam scanning of an angle domain; and based on the multi-user distance domain codebook, carrying out distance domain beam scanning on a plurality of users at the same time. The multi-user angle domain codebook and the multi-user distance domain codebook are utilized to realize angle scanning and distance scanning of multiple users at the same time, the beam training overhead is remarkably reduced, the total overhead is the order of magnitude of the number of antenna units and does not increase along with the number of the users, the beam training precision and the system throughput are improved, and the beam training efficiency is improved. And research and application of near-field multi-user beam forming are promoted.

Description

Technical Field

[0001] The present application belongs to the field of wireless communication technology, and specifically relates to a beam training method and device based on a holographic metasurface. Background Art

[0002] In wireless communication systems assisted by ultra-large-scale antenna arrays, a large number of antenna units and users multiply the number of wireless links in the system. In order to obtain channel information to complete beamforming, traditional pilot-based channel estimation schemes face huge time overhead. The codebook-based beam training method can complete beamforming without obtaining accurate channel information. As the array aperture increases, the near-field area corresponding to the array also expands accordingly. A large number of users are distributed in the near-field area. It is necessary to design codebooks and beam training schemes in the angle-distance binary domain to match user channels. However, multi-user near-field beam training faces the problem of dual overhead in the angle and distance dimensions and the increase of training overhead with the number of users. It is necessary to design a low-overhead near-field beam training scheme whose training overhead does not increase with the number of users to solve the near-field multi-user beamforming problem of ultra-large-scale array communication systems.

[0003] In response to this situation, a common approach is to design a multi-user training scheme based on machine learning, or to implement multi-user beam training through multi-beam design. The problem with the beam training scheme based on machine learning is that it is necessary to continuously expand user data to update the training model to serve the current specific user distribution, which faces a large system maintenance complexity and is difficult to implement in actual system design. In the scheme using multi-beam design, it is still necessary to perform beam training for different users separately in the angle domain, which makes the training overhead increase with the number of users. Summary of the invention

[0004] Based on the above technical problems, the present application proposes a beam training method and device based on a holographic metasurface, which generates a multi-user angle domain codebook that can perform angle scanning on multiple users at the same time. It does not require additional hardware units and has low cost. It can also perform distance scanning on multiple users at the same time, significantly reducing the beam training overhead. The total overhead is on the logarithmic order of the number of antenna units and does not increase with the number of users. It improves the beam training accuracy and system throughput, and promotes the research and application of near-field multi-user beamforming.

[0005] The first embodiment of the present application proposes a beam training method based on a holographic metasurface, the method comprising:

[0006] Based on the parameter data of the holographic metasurface and the preset angle domain codebook structure information, a multi-user angle domain codebook is generated; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of the codewords are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship;

[0007] Based on the multi-user angle-domain codebook, simultaneously performing angle-domain beam scanning on multiple users within the signal coverage range of the holographic metasurface;

[0008] Generate a multi-user range domain codebook based on the angle sets of the multiple users obtained by the beam scanning in the angle domain;

[0009] Based on the multi-user range domain codebook, beam scanning in the range domain is performed on the multiple users simultaneously.

[0010] In some embodiments of the present application, the generating of a multi-user angle domain codebook based on parameter data of the holographic metasurface and preset angle domain codebook structure information includes:

[0011] Based on the preset angle domain codebook structure information and the signal coverage range of the holographic metasurface, determining the angle coverage area corresponding to each codeword in each of the codeword layers;

[0012] Based on the angular coverage area corresponding to each codeword and the parameter data of the holographic metasurface, respectively calculating the value of each codeword;

[0013] According to the angle coverage area corresponding to each codeword in each codeword layer, the value of each codeword is arranged into the multi-user angle domain codebook.

[0014] In some embodiments of the present application, the preset angle domain codebook structure information includes the number of codeword layers, the first preset number and the recursive relationship;

[0015] The determining, based on the preset angle domain codebook structure information and the signal coverage range of the holographic metasurface, the angle coverage area corresponding to each codeword in each codeword layer comprises:

[0016] Dividing the signal coverage range of the holographic metasurface into an angle domain and a distance domain, performing a second preset number of equidistant samplings in the angle domain, and performing a third preset number of equidistant samplings in the distance domain, to obtain a plurality of sampling coordinates;

[0017] Based on the number of codeword layers, the preset number, the recursive relationship and the sampling coordinates, the angular coverage area corresponding to each codeword in each codeword layer is determined respectively, and the angular coverage area corresponding to the codeword includes each sampling coordinate within the beam coverage range of the codeword.

[0018] In some embodiments of the present application, the value of each codeword is calculated based on the angle coverage area corresponding to each codeword and the parameter data of the holographic metasurface, including:

[0019] Based on the angular coverage area corresponding to the first codeword, determining the beam gain corresponding to each sampling coordinate in the angular coverage area corresponding to the first codeword; the first codeword is any one of the codewords;

[0020] Calculating a steering vector based on the sampling coordinates and antenna unit information included in the parameter data of the holographic metasurface;

[0021] Calculate a base station digital beamforming vector based on the number of users and the antenna unit information included in the parameter data;

[0022] Based on the antenna unit information, determining an amplitude response of the antenna unit in the holographic metasurface;

[0023] The value of the first codeword is calculated based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit.

[0024] In some embodiments of the present application, the calculating the value of the first codeword based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the holographic beamformer includes:

[0025] Calculate the value of the first codeword by the following formula based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit;

[0026]

[0027] In the above formula, m is the amplitude of the antenna unit, n is the serial number of the antenna unit, and m n is the amplitude of the nth antenna element; i is the sampling number in the angle domain of the signal coverage range, j is the sampling number in the distance domain of the signal coverage range, ψ i is the i-th sampling angle in the angle domain, μ j is the jth sampling distance in the distance domain; b(ψi ,μ j ) is the sampling coordinate (ψ i ,μ j ), Where N is the total number of antenna units in the holographic metasurface, λ is the carrier wavelength, r n is the sampling coordinate (ψ i ,μ j ) and the distance between the nth antenna unit, r is the sampling coordinate (ψ i ,μ j ) and the distance between the center point of the holographic metasurface;

[0028] v is the base station digital beamforming vector, Wherein, P is the total power of the base station corresponding to the holographic metasurface, K is the number of users, and L is the number of feed sources of the holographic metasurface;

[0029] M is the amplitude response of the antenna unit, G i,j The first codeword is at the sampling coordinate (ψ i ,μ j ) beam gain, stG i,i The first codeword is at the sampling coordinate (ψ i ,μ j ) at a beam gain constraint function; the first codeword is the p-th codeword in the s-th layer, is the angular coverage area corresponding to the first codeword, and D is the value of the beam gain.

[0030] In some embodiments of the present application, the method of simultaneously performing angle-domain beam scanning on multiple users within the signal coverage range of the holographic metasurface based on the multi-user angle-domain codebook includes:

[0031] Based on the codewords in the first codeword layer in the multi-user angle domain codebook, adjusting the amplitude of each antenna unit in the holographic metasurface; the first codeword layer is any codeword layer in the multiple codeword layers;

[0032] Sending a signal to the signal coverage range through the adjusted holographic metasurface, and receiving a codeword sequence number fed back by each user within the signal coverage range;

[0033] Based on the codeword sequence numbers fed back by the users corresponding to the codeword layers, the angles at which the users are located within the signal coverage are determined respectively.

[0034] In some embodiments of the present application, the angle sets of the multiple users obtained based on the beam scanning in the angle domain, generating a multi-user range domain codebook, includes:

[0035] Determine the angles of the plurality of users obtained based on the beam scanning in the angle domain, and determine the angles of each user having the same distance in the angle set;

[0036] Determining, from the multi-user angle domain codebook, codewords corresponding to the user angles having the same distance;

[0037] The codewords corresponding to the user angles with the same distance are superimposed to obtain multi-beam codewords corresponding to different distances;

[0038] The multi-beam codewords are constructed into the multi-user range domain codebook.

[0039] In some embodiments of the present application, superimposing the codewords corresponding to the user angles with the same distance to obtain the multi-beam codewords corresponding to the different distances includes:

[0040] Based on the codewords corresponding to the angles of each user at the same distance, the multi-beam codewords corresponding to different distances are obtained by the following formula;

[0041]

[0042] In the above formula, μ j is the jth sampling distance, k is the sequence number of the user angle in the angle set, K is the total number of user angles in the angle set, ψ k is the kth user angle, m j is the multi-beam codeword corresponding to the jth sampling distance, m(ψ k ,μ j ) is the beam coverage coordinate (ψ k ,μ j ) codeword.

[0043] In some embodiments of the present application, the simultaneously performing range-domain beam scanning on the multiple users based on the multi-user range-domain codebook includes:

[0044] Based on a multi-user range domain codebook, adjusting the amplitude of each antenna unit in the holographic metasurface;

[0045] Sending a signal to the signal coverage range through the adjusted holographic metasurface, and receiving a codeword sequence number fed back by each user within the signal coverage range;

[0046] Based on the distance domain range corresponding to the signal coverage range and the codeword sequence number fed back by each user, the distance of each user is determined respectively.

[0047] The second aspect of the present application proposes a beam training device based on a holographic metasurface, the device comprising:

[0048] A multi-user angle domain codebook generation module is used to generate a multi-user angle domain codebook based on parameter data of a holographic metasurface and preset angle domain codebook structure information; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of the codewords are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship;

[0049] A multi-user angle domain scanning module, configured to simultaneously perform angle domain beam scanning on multiple users within the signal coverage range of the holographic metasurface based on the multi-user angle domain codebook;

[0050] A multi-user range domain codebook generation module, configured to generate a multi-user range domain codebook based on the angle sets of the multiple users obtained by beam scanning in the angle domain;

[0051] A multi-user range domain scanning module is used to simultaneously perform range domain beam scanning on the multiple users based on the multi-user range domain codebook.

[0052] The technical solution provided in the embodiments of the present application has at least the following technical effects or advantages:

[0053] In the embodiment of the present application, a multi-user angle domain codebook is generated that can perform angle scanning on multiple users at the same time, without adding additional hardware units, and the cost is low. In addition, a multi-user distance domain codebook is designed, which can perform distance scanning on multiple users at the same time. The multi-user angle domain codebook and the multi-user distance domain codebook are used to realize angle scanning and distance scanning of multiple users at the same time, which significantly reduces the beam training overhead. The total overhead is the logarithmic order of the number of antenna units and does not increase with the number of users, which improves the beam training accuracy and system throughput, and promotes the research and application of near-field multi-user beamforming.

[0054] 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

[0055] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present application. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0056] In the attached picture:

[0057] Figure 1 A flow chart of a beam training method for a holographic metasurface provided in one embodiment of the present application is shown;

[0058] Figure 2 A schematic diagram of the structure of a multi-user angle domain codebook provided by an embodiment of the present application is shown;

[0059] Figure 3 Shows Figure 2 A schematic diagram of the angle coverage domains of codewords 1 and 2 in the second codeword layer, the fourth codeword layer, and the sixth codeword layer in the structure of the multi-user angle domain codebook shown;

[0060] Figure 4 Another flow chart of the beam training method of the holographic metasurface provided by one embodiment of the present application is shown;

[0061] Figure 5 A schematic diagram showing the coverage of a range multi-beam codeword provided by an embodiment of the present application is shown;

[0062] Figure 6 A schematic diagram showing actual coverage of different distance domain codewords provided by an embodiment of the present application;

[0063] Figure 7 A schematic diagram of a throughput-number of users curve provided by an embodiment of the present application is shown;

[0064] Figure 8 A schematic structural diagram of a beam training device for a holographic metasurface provided in one embodiment of the present application is shown;

[0065] Fig. 9 A schematic diagram of the structure of an electronic device provided by an embodiment of the present application is shown;

[0066] Fig.10 A schematic diagram of a storage medium provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0067] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0068] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by technicians in the field to which this application belongs.

[0069] Driven by the exponential growth of smart applications, 6G networks are expected to support peak data rates of 100Gb / s, and large-scale arrays are expected to meet this demand. Traditional phase-controlled arrays or metasurfaces rely on high-resolution phase shifters, which face sharply rising hardware costs and power consumption when the number of antenna units increases significantly, hindering the development of ultra-large-scale arrays.

[0070] Reconfigurable holographic surface (RHS) is an amplitude-controlled metasurface that does not rely on the use of phase shifters, and each antenna does not need to be equipped with a separate feed line. The amplitude of each RHS unit is controlled only by a simple diode circuit. It is a low-cost, low-energy way to realize ultra-large-scale arrays, and is expected to break through the bottleneck of traditional phased arrays.

[0071] Although RHS provides a potential solution for deploying large-scale arrays, the number of channel links also increases proportionally with the number of units and users, which leads to a sharp increase in the complexity of beamforming using traditional pilot-based channel estimation schemes. In order to avoid obtaining accurate channel state information, low-overhead beam training has become a practical method for beamforming, that is, beamforming is completed through the design of codebooks and beam training schemes. Before beamforming, a codebook is pre-designed, which contains different codewords. Each codeword can generate a directional beam in one direction. The optimal codeword matching the user channel is found through beam training.

[0072] As the size of the ultra-large-scale metasurface increases, the corresponding near-field area also expands, and beam training needs to be performed in the angle-distance binary domain. Traditional near-field multi-user beam training faces the problem of dual training overhead in the distance dimension and the angle dimension, as well as the problem that the training overhead grows linearly with the number of users.

[0073] Existing technologies mainly use machine learning or multi-beam design solutions to serve multiple users to reduce training costs. However, machine learning-based solutions require continuous model updates to adapt to specific user distributions, which is too complex; and multi-beam design solutions still require separate training for different users in the angle domain, and the training cost is proportional to the number of users.

[0074] Therefore, it is of great practical significance to design a near-field beam training scheme in which the training overhead does not increase with the number of users. Based on this, the embodiment of the present application provides a beam training method based on a holographic metasurface, which utilizes the amplitude control characteristics of RHS to design a multi-user angle domain codebook capable of simultaneously performing angle scanning on multiple users, and utilizes the holographic pattern superposition principle of RHS to design a multi-user distance domain codebook capable of simultaneously performing distance scanning on multiple users. The use of a multi-user angle domain codebook and a multi-user distance domain codebook realizes simultaneous angle scanning of multiple users and simultaneous distance scanning of multiple users, significantly reducing the beam training overhead. The total overhead is in the logarithmic order of the number of antenna units and does not increase with the number of users. Compared with the traditional near-field beam training scheme, the method provided in the embodiment of the present application improves the beam training accuracy and system data rate, and promotes the research and application of near-field multi-user beamforming.

[0075] The following describes a beam training method and device based on a holographic metasurface according to an embodiment of the present application in conjunction with the accompanying drawings.

[0076] See also Figure 1 The flowchart of the beam training method based on holographic metasurface is shown, and the method includes the following steps 101-104.

[0077] Step 101: Based on parameter data of a holographic metasurface and preset angle domain codebook structure information, a multi-user angle domain codebook is generated; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of each codeword are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship.

[0078] Step 102: Based on the multi-user angle-domain codebook, angle-domain beam scanning is performed simultaneously on multiple users within the signal coverage range of the holographic metasurface.

[0079] Step 103: Generate a multi-user range domain codebook based on the angle sets of multiple users obtained by beam scanning in the angle domain.

[0080] Step 104: Based on the multi-user range domain codebook, perform range domain beam scanning on multiple users simultaneously.

[0081] The above-mentioned holographic metasurface can be the above-mentioned reconfigurable holographic metasurface RHS. The execution subject of the embodiment of the present application can be the device to which the holographic metasurface belongs or the controller of the device, or the execution subject can also be the host computer of the device to which the holographic metasurface belongs. The host computer can construct a multi-user angle domain codebook and a multi-user distance domain codebook according to the method provided in the embodiment of the present application, and control the holographic metasurface based on the multi-user angle domain codebook and the multi-user distance domain codebook to perform angle scanning and distance scanning on multiple users within the signal coverage range of the holographic metasurface.

[0082] The preset angle domain codebook structure information defines the structure of the multi-user angle domain codebook, such as the number of codeword layers contained in the multi-user angle domain codebook, the number of codewords contained in each codeword layer, the setting method of the angle coverage area of ​​each codeword in the same codeword layer, the recursive relationship between the angle coverage areas of codewords in different codeword layers, etc.

[0083] Specifically, the number of codeword layers included in the preset angle domain codebook structure information is a positive integer greater than 1, and the number of codewords contained in each codeword layer is the same, which is a first preset number of codewords, and the first preset number is a positive integer greater than 1. Each codeword in each codeword layer includes at least one continuous angle coverage area, such as each codeword in some codeword layers has 1 continuous angle coverage area, and each codeword in some codeword layers has 2 or more continuous angle coverage areas. The number of angle coverage areas included in each codeword in the same codeword layer may be the same or different. The angle coverage areas included in each codeword in the same codeword layer are arranged at intervals, that is, multiple angle coverage areas of the same codeword are not continuous, and are separated by angle coverage areas of other codewords. There is a recursive relationship between the angular coverage areas of the same codeword in two adjacent codeword layers in multiple codeword layers. The recursive relationship can be that the single angular coverage area of ​​the same codeword in the upper codeword layer of the two adjacent codeword layers is an integer multiple of the single angular coverage area of ​​the same codeword in the lower codeword layer, and the integer multiple can be an integer multiple greater than 1, such as 2 times, 3 times, etc.

[0084] Figure 2 A schematic diagram of the multi-user angle domain codebook structure is shown in Figure 2Multiple codeword layers are shown, each codeword layer has two codewords, and in each codeword layer, the angular coverage area of ​​the two codewords each occupies half of the angular domain. In the first codeword layer, codeword 1 has only one continuous angular coverage area, and the size of the angular coverage area is half of the angular domain. In the second codeword layer, codeword 1 has two angular coverage areas, and the two angular coverage areas are of the same size, both of which are one-fourth of the angular domain, and the two angular coverage areas are not adjacent, but are separated by the angular coverage area of ​​codeword 2. In the third codeword layer and subsequent codeword layers, the number of angular coverage areas of codeword 1 increases layer by layer, while the size of the angular coverage area decreases layer by layer. It should be noted that the two codewords in each codeword layer are different codewords, that is to say Figure 2 The codewords 1 in each codeword layer are all different codewords, and the codewords 2 in each codeword layer are also different codewords.

[0085] Figure 3 Shows Figure 2 The angle coverage of codewords in multiple codeword layers in the multi-user angle domain codebook shown, Figure 3 (a), (b) and (c) are Figure 2 The actual angular coverage of codeword 1 and codeword 2 in the second codeword layer, the fourth codeword layer, and the sixth codeword layer.

[0086] The parameter data of the holographic metasurface include antenna unit information and the number of users of the holographic metasurface. The antenna unit information includes the total number of antenna units in the holographic metasurface, the serial number of each antenna unit, the carrier wavelength of the holographic metasurface, the coordinates of each antenna unit, the coordinates of the center point of the holographic metasurface, the total power of the base station corresponding to the holographic metasurface, the coordinates of each feed source in the holographic metasurface, the serial number of each feed source, the number of feed sources, the electromagnetic propagation vector of the holographic metasurface, etc.

[0087] The process of performing multi-beam training in the above steps 101-104 can be summarized as follows: Figure 4 The process shown is to obtain a multi-user angle domain codebook based on the amplitude control characteristics of the holographic metasurface. And obtain a multi-user distance domain codebook based on the holographic pattern superposition principle of the holographic metasurface. Then, beam training is performed on multiple users simultaneously based on the multi-user angle domain codebook and the multi-user distance domain codebook.

[0088] The above-mentioned amplitude control characteristic means that the holographic metasurface can construct a holographic pattern by adjusting the amplitude response of the antenna unit, thereby achieving precise control of beamforming. The holographic pattern superposition principle means that multiple single-beam codewords can be directly superimposed to obtain a multi-beam codeword. Among them, the holographic pattern refers to the directional holographic pattern corresponding to the codeword, and the amplitude response of the antenna unit can also be the amplitude of the antenna unit.

[0089] The above embodiment generates a multi-user angle domain codebook that can perform angle scanning on multiple users at the same time, without adding additional hardware units, and has low cost. In addition, a multi-user distance domain codebook is designed, which can perform distance scanning on multiple users at the same time. The multi-user angle domain codebook and the multi-user distance domain codebook are used to realize angle scanning and distance scanning of multiple users at the same time, which significantly reduces the beam training overhead. The total overhead is the logarithmic order of the number of antenna units and does not increase with the number of users, which improves the beam training accuracy and system throughput, and promotes the research and application of near-field multi-user beamforming.

[0090] In some embodiments of the present application, the generation process of a multi-user angle domain codebook may include: determining the angle coverage area corresponding to each codeword in each codeword layer based on preset angle domain codebook structure information and the signal coverage range of the holographic metasurface; calculating the value of each codeword based on the angle coverage area corresponding to each codeword and parameter data of the holographic metasurface; and arranging the value of each codeword into a multi-user angle domain codebook according to the angle coverage area corresponding to each codeword in each codeword layer.

[0091] The preset angle domain codebook structure information may be pre-configured in the device. The codeword may be considered as the amplitude vector of the holographic metasurface. There are multiple elements in the codeword, and the number of elements is the same as the number of antenna units of the holographic metasurface. Each element represents the amplitude of each antenna unit. The amplitude of each antenna unit is calculated separately to obtain a codeword.

[0092] Based on the preset angle domain codebook structure information, the signal coverage range of the holographic metasurface and the parameter data of the holographic metasurface, a multi-user angle domain codebook capable of simultaneously performing angle scanning on multiple users can be obtained through calculation and design. There is no need to add additional hardware components and the hardware cost of the holographic metasurface will not be increased. Multi-user simultaneous scanning in the angle domain can be achieved through calculation, which reduces the overhead of simultaneous angle scanning of multiple users in the near field and ensures that the beam training overhead does not increase with the increase in the number of users.

[0093] In some embodiments of the present application, the angular coverage area corresponding to each codeword in each codeword layer can be determined in the following manner: dividing the signal coverage range of the holographic metasurface into an angle domain and a distance domain, performing a second preset number of equidistant sampling in the angle domain, and performing a third preset number of equidistant sampling in the distance domain to obtain multiple sampling coordinates; based on the number of codeword layers, the preset number, the recursive relationship and the sampling coordinates, the angular coverage area corresponding to each codeword in each codeword layer is determined respectively, and the angular coverage area corresponding to the codeword includes each sampling coordinate within the beam coverage range of the codeword.

[0094] The signal coverage of the holographic metasurface is the area served by the holographic metasurface, or the area that the signal emitted by the holographic metasurface can radiate. The angle domain and the distance domain are respectively equivalent to the horizontal axis and the vertical axis of the signal coverage of the holographic metasurface. The signal coverage of the holographic metasurface is sampled equidistantly for a second preset number of times in the direction of the angle domain. Assuming that the second preset number is I, I sampling angles are obtained by sampling, ψ i In the direction of the distance domain, the signal coverage range of the holographic metasurface is sampled equidistantly for a third preset number of times. Assuming that the third preset number is J, J sampling distances are obtained by sampling, μ j represents the jth sampling distance.

[0095] Use [ψ min ,ψ max ] represents the angle domain coverage of the signal coverage of the holographic metasurface, that is, the angle domain coverage of the multi-user angle domain codebook obtained in the end. min ,μ max ] represents the distance domain coverage of the signal coverage of the holographic metasurface, that is, the distance domain coverage of the multi-user distance domain codebook obtained in the end. Then the above ψ i ∈[ψ min ,ψ max ],μ j ∈[μ min ,μ max ] where ψ i = cosθ, θ is the sampling coordinate (ψ i ,μ j ) to the center of the holographic metasurface, r is the sampling coordinate (ψ i ,μ j ) to the center point of the holographic metasurface.

[0096] In order to perform beam scanning for all users simultaneously in the angle domain, a multi-user angle domain codebook is designed that conforms to the preset angle domain codebook structure information. Figure 2 Each layer shown has only two codewords, each codeword covers half of the angle domain, and there is a recursive relationship between the codeword coverage of two adjacent layers. Assume that the pth codeword in the sth layer is m s,p , codeword m s,p Beam coverage The point (ψ i ,μ j )satisfy:

[0097] After obtaining multiple sampling coordinates in the signal coverage range of the holographic metasurface in the above manner, the angle coverage area corresponding to each codeword in each codeword layer is determined according to the preset angle domain codebook structure information and the multiple sampling coordinates. The angle coverage area corresponding to the codeword is equivalent to the set of sampling coordinates that can be covered by the beam of the codeword.

[0098] The above embodiment performs sampling in the angle domain and the distance domain within the signal coverage range of the holographic metasurface to obtain multiple sampling coordinates, and then determines the angle coverage area of ​​each codeword in each codeword layer in the multi-user angle domain codebook to be generated based on the preset angle domain codebook structure information. Since there are multiple codeword layers, each codeword layer has different codewords, and each codeword has a different angle coverage area, in the subsequent beam training process in the angle domain, the beam with the highest signal strength received by users at different angles is the beam corresponding to different codewords. The codeword sequence number corresponding to the beam with the highest signal strength fed back by the user can enable the device to determine the angle of the user, thereby realizing the ability to perform angle domain beam training for multiple users at the same time.

[0099] In some embodiments of the present application, after determining the structure of the multi-user angle domain codebook to be generated and the angle coverage area of ​​each codeword in the structure in the above manner, the specific value of each codeword is determined in the following manner, and then the specific value of each codeword is arranged according to the determined codebook structure to obtain the multi-user angle domain codebook.

[0100] Since the process of determining the value of each codeword is the same, any codeword in the above codebook structure is called the first codeword. The process of determining the value of the first codeword is introduced below, and the process of determining the value of other codewords can refer to the process of determining the value of the first codeword.

[0101] Specifically, based on the angular coverage area corresponding to the first codeword, the beam gain corresponding to the first codeword at each sampling coordinate in the angular coverage area corresponding to the first codeword is determined; based on each sampling coordinate and the antenna unit information included in the parameter data of the holographic metasurface, the steering vector is calculated; based on the number of users and the antenna unit information included in the parameter data, the base station digital beamforming vector is calculated; based on the antenna unit information, the amplitude response of the antenna unit in the holographic metasurface is determined; based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit, the value of the first codeword is calculated.

[0102] The number of elements included in the first codeword is equal to the number of antenna units of the holographic metasurface, and the value of the element is the amplitude of the antenna unit corresponding to the element. Therefore, the amplitude of each antenna unit is calculated, and the amplitude vector composed of the amplitudes of all antenna units is the first codeword.

[0103] Based on the angular coverage area corresponding to the first codeword, the beam gain of the first codeword at each sampling coordinate covered by the first codeword is determined, which helps to achieve high beam gain at the sampling coordinates covered by the first codeword and achieve zero beam gain at the sampling coordinates that the first codeword cannot cover. This can improve the accuracy of the first codeword and further improve the accuracy of beam training and final beamforming.

[0104] The steering vector is used to describe the spatial phase difference and is used for beamforming, which aims to send or receive radio waves in a specific direction and shape. The amplitude response of an antenna element is the sum of the responses of the antenna element to all feeds in the holographic metasurface.

[0105] Through the above embodiments, the beam gain, steering vector, base station digital beamforming vector and amplitude response of the antenna unit of the first codeword at each sampling coordinate are determined, and the value of the first codeword can be calculated without adding additional hardware components and increasing hardware costs. The value of the codeword can be determined through simple mathematical calculations, thereby improving the efficiency and accuracy of generating a multi-user angle domain codebook.

[0106] In some embodiments of the present application, based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit, the value of the first codeword is calculated by the following formula (1);

[0107]

[0108] In formula (1), m is the amplitude of the antenna unit, n is the serial number of the antenna unit, and m n is the amplitude of the nth antenna element; i is the sampling number in the angle domain of the signal coverage range, j is the sampling number in the distance domain of the signal coverage range, ψ i is the i-th sampling angle in the angle domain, μ j is the jth sampling distance in the distance domain; b(ψ i ,μ j ) is the sampling coordinate (ψ i ,μ j ), Where N is the total number of antenna units in the holographic metasurface, λ is the carrier wavelength, and r1 is the sampling coordinate (ψ i ,μ j ) and the distance between the first antenna unit, r n is the sampling coordinate (ψ i ,μ j ) and the distance between the nth antenna unit, r is the sampling coordinate (ψ i ,μ j ) and the distance between the center point of the holographic metasurface; δn is the number of the nth antenna unit;

[0109] v is the base station steering vector, Among them, P is the total power of the base station corresponding to the holographic metasurface, K is the number of users, and L is the number of feed sources of the holographic metasurface;

[0110] M is the amplitude response of the antenna unit, G i,j is the first codeword at the sampling coordinate (ψ i ,μ j ) beam gain, stG i,j is the first codeword at the sampling coordinate (ψ i ,μ j ) is a constraint function of the beam gain at ; the first codeword is the pth codeword in the sth layer, is the angular coverage area corresponding to the first codeword, and D is the value of the beam gain.

[0111] The amplitude response M of the antenna unit is explained below. As a leaky wave antenna, electromagnetic waves propagate continuously in the holographic metasurface to generate a directional beam. The transmission signal from the RF link is fed into the holographic metasurface through the feed source, and the signal excites each antenna unit on the holographic metasurface in turn. Assuming that the holographic metasurface has N antenna units and L feed sources, the response of the lth feed source at the nth antenna unit is where d n,l is the distance vector between the lth feed and the nth antenna element, k s is the electromagnetic propagation vector of the holographic metasurface, and j is an imaginary unit. In order to characterize the propagation loss of electromagnetic waves on the holographic metasurface, the path loss is expressed as where α is the path loss exponent. M is defined as the amplitude response of the antenna unit in the holographic metasurface, where [M] n,l is the amplitude response of the lth feed arriving at the nth antenna element Assume that the amplitude of antenna element n is m n ∈[0,1], then the amplitude response of the nth antenna element is the sum of the responses to all feeds, expressed as: Where η is the energy efficiency radiated by each antenna unit.

[0112] Solve the above formula (1), for the amplitude m of the nth antenna element n , while fixing other m ′ n (n ′ ≠n), the above formula (1) can be expanded to n The quadratic function f(m n ):

[0113]

[0114] Among them, a n is the coefficient of the quadratic term, b n is the coefficient of the first-order term, c n is the constant term coefficient.

[0115] Where i is the sampling number in the angle domain of the signal coverage range, j is the sampling number in the distance domain of the signal coverage range, I is the total number of samples in the angle domain, and J is the total number of samples in the distance domain. i,j,n =|γ n | 2 [B] n,n

[0116]

[0117] Where B is the auxiliary matrix, B = b(ψ i ,μ j ) H b(ψ i ,μ j ), b(ψ i ,μ j ) is the sampling coordinate (ψ i ,μ j ), H represents the conjugate transpose of the vector. n To calculate the factor, η is the energy efficiency of each unit radiation, P is the total power of the base station corresponding to the holographic metasurface, K is the number of users, and L is the number of feed sources of the holographic metasurface. RE is a function used to take the real part of a complex number.

[0118] The same characters in the above formula have the same physical meaning. For the case where the characters are the same but have different subscripts, the meanings of the other characters with different subscripts can be derived based on the interpretation of the characters with one of the subscripts.

[0119] The above function f(m n ) on [0,1] can be obtained from the properties of quadratic functions. n ) When the minimum value is obtained, m n The value of is the optimal value of the amplitude of the nth antenna unit. For the other antenna units in the holographic metasurface, the optimal values ​​of the amplitudes of the other antenna units are calculated according to the above process. Then the optimal values ​​of the amplitudes of the antenna units in the holographic metasurface form a codeword, that is, m = [m1,…,m N ].

[0120] The amplitude of the antenna unit is expressed by a function formula and converted into the minimum value of solving a quadratic equation, so that the optimal value of the amplitude of each antenna unit can be accurately obtained by mathematical calculation. Furthermore, a multi-user angle domain codebook capable of simultaneously performing angle scanning on multiple users can be generated without adding hardware units.

[0121] The values ​​of each codeword in each codeword layer of the multi-user angle domain codebook are obtained through the above embodiment, and the values ​​of each codeword are arranged according to the structure of the multi-user angle domain codebook, that is, the multi-user angle domain codebook is obtained. Then, the angle scanning of multiple users is performed through the following process: based on the codeword in the first codeword layer in the multi-user angle domain codebook, the amplitude of each antenna unit in the holographic metasurface is adjusted; the first codeword layer is any codeword layer in multiple codeword layers; the signal is sent to the signal coverage range through the adjusted holographic metasurface, and the codeword sequence number fed back by each user in the signal coverage range is received; based on the codeword sequence number fed back by each user corresponding to each codeword layer, the angle of each user in the signal coverage range is determined respectively.

[0122] In the multi-user angle scanning process, the base station uses a multi-user angle domain codebook, uses a first preset number of codewords to broadcast information in each codeword layer, and after receiving the signal of the codeword layer, user k feeds back the codeword number τ that makes the received signal stronger. k,s , after completing the beam training of all S codeword layers, the feedback information of user k is [τ k,1 ,…,τ k,S ]. According to the recursive relationship of the angle coverage of codewords in the multi-user angle domain codebook, the angle number corresponding to user k in the sth layer can be expressed as ν k,s =2(ν k,s-1 -1)+τ k,s , where ν k,0 =1, from which the angle number ν corresponding to user k in the sth layer can be calculated k,S . Given the codebook’s angular domain coverage [ψ min ,ψ max ], the angle of user k can be calculated After completing the multi-user angle scanning, the base station simultaneously obtains the angle set of multiple users

[0123] Since the multi-user angle domain codebook is used to realize simultaneous angle scanning of multiple users during the angle scanning process, the overhead of beam training in the angle domain is only in the logarithmic order of the number of antenna units, and the overhead will not increase with the increase in the number of users.

[0124] In some embodiments of the present application, the generation process of a multi-user distance domain codebook may include: determining the angles of each user with the same distance in the angle set based on the angle set of multiple users obtained by beam scanning in the angle domain; determining the codewords corresponding to the angles of each user with the same distance from the multi-user angle domain codebook; superimposing the codewords corresponding to the angles of each user with the same distance to obtain multi-beam codewords corresponding to different distances; and constructing each multi-beam codeword into a multi-user distance domain codebook.

[0125] For traditional phased arrays, multi-beam codewords cannot be obtained by directly adding single-beam codewords, because their antenna units need to meet constant modulus constraints, and the design of multi-beam codewords using beam optimization methods requires time overhead and cannot be applied in real time during beam training. However, this application is a beam training method based on a holographic metasurface. For a holographic metasurface, the addition of the holographic patterns of single-beam codewords can obtain a new holographic pattern and meet the amplitude limit of the antenna units of the holographic metasurface, that is, multi-beam codewords can be generated by directly adding single-beam codewords. In the superposition process of the single-beam patterns of the holographic metasurface, the amplitude of each antenna unit is superimposed, while the phase information remains unchanged, thereby avoiding aliasing of the beam coverage range.

[0126] Assume that the single beam codeword [m1,…,m K ] respectively cover the sampling points [(ψ1,μ1),…,(ψ K ,μ K )], by using the holographic pattern superposition principle of the holographic metasurface, the above codewords can be directly added together to construct a codeword that simultaneously covers [(ψ1,μ1),…,(ψ K ,μ K )], expressed as

[0127]

[0128] During the beam training process, after obtaining the angle set of multiple users using the multi-user angle domain codebook, the range multi-beam codewords covering all user angles can be generated in real time by superimposing holographic patterns. These range multi-beam codewords can be used to perform range scans on all users simultaneously. Figure 5 As shown in the figure, each small rectangle can be understood as a single-beam codeword. Different small rectangles of the same color represent single-beam codewords with the same distance but different angles. The single-beam codewords corresponding to different small rectangles of the same color can be directly superimposed to obtain multi-beam codewords covering the angles and distances of these small rectangles. Figure 6 The actual distance coverage of different distance domain codewords is shown in FIG.

[0129] Since the method of generating multi-beam codewords is to directly superimpose single-beam codewords, a single-beam codebook can be obtained first, which includes all possible single-beam codewords [m(ψ1,μ1),…,m(ψ I ,μ J )], these single-beam codewords cover [(ψ1,μ1),…,(ψ I ,μ J )]. On this basis, after the angle scanning of multi-user beam training, the angle set of the user is Ψ=[ψ1,…,ψ K ]. On this basis, based on the codewords corresponding to the angles of each user at the same distance in the above embodiment, the multi-beam codewords corresponding to different distances can be obtained by the following formula:

[0130]

[0131] In the formula, μ j is the jth sampling distance, k is the serial number of the user angle in the angle set, or it can also be called the kth user, K is the total number of user angles in the angle set, ψ k is the angle of the kth user, m j is the multi-beam codeword corresponding to the jth sampling distance, m(ψ k ,μ j ) is the beam coverage coordinate (ψ k ,μ j ) codeword.

[0132] The multi-beam codeword m corresponding to the j-th sampling distance is calculated by the above formula j For other sampling distances among the J sampling distances, the multi-beam codewords corresponding to the other sampling distances are calculated respectively in the same manner as above, and the obtained J multi-beam codewords constitute a multi-user distance domain codebook.

[0133] Before the range scanning phase begins, a multi-user range domain codebook [m1,…,m J ], since the multi-user range domain codebook is generated by direct superposition of holographic patterns, the time spent is negligible.

[0134] After obtaining the multi-user distance domain codebook in the above manner, the distance scan of multiple users is performed simultaneously in the following manner: based on the multi-user distance domain codebook, the amplitude of each antenna unit in the holographic metasurface is adjusted; the signal is sent to the signal coverage range through the adjusted holographic metasurface, and the codeword sequence number fed back by each user within the signal coverage range is received; based on the distance domain range corresponding to the signal coverage range and the codeword sequence number fed back by each user, the distance of each user is determined respectively.

[0135] The base station uses J range domain codewords in the multi-user range domain codebook to transmit signals, and user k feeds back the codeword sequence number ζ that maximizes its received power. k , given the range domain coverage of the multi-user range domain codebook [μ min ,μ max ], the distance of user k can be calculated as: After completing the multi-user distance scan, the base station simultaneously obtains the distance set of the user

[0136] After obtaining the angle and distance information of all users, beamforming can be completed using the single beam codeword corresponding to the angle and distance information of the user. Since the beam training in the angle domain and distance domain stages are performed on all users simultaneously, the beam training overhead of the proposed scheme is only log2I+J, which does not increase with the number of users K.

[0137] The beam training method provided in the embodiment of the present application can effectively improve the throughput of the system. Figure 7 The throughput-number-of-users curve shown in FIG. 1 compares the difference between the beam training method provided in the embodiment of the present application and the two-stage beam training scheme and the DFT (Discrete Fourier Transform)-range beam training scheme in improving the system throughput. Figure 7 It is intuitively demonstrated that the beam training method provided in the embodiment of the present application significantly improves the system throughput compared with the two methods in the related art.

[0138] In the embodiment of the present application, a multi-user angle domain codebook is generated that can perform angle scanning on multiple users at the same time, without adding additional hardware units, and the cost is low. In addition, a multi-user distance domain codebook is designed, which can perform distance scanning on multiple users at the same time. The multi-user angle domain codebook and the multi-user distance domain codebook are used to realize angle scanning and distance scanning of multiple users at the same time, which significantly reduces the beam training overhead. The total overhead is the logarithmic order of the number of antenna units and does not increase with the number of users, which improves the beam training accuracy and system throughput, and promotes the research and application of near-field multi-user beamforming.

[0139] The embodiment of the present application also provides a beam training device based on a holographic metasurface, which is used to execute the beam training method based on a holographic metasurface provided in any of the above embodiments. Figure 8 , the device comprises:

[0140] The multi-user angle domain codebook generation module 201 is used to generate a multi-user angle domain codebook based on the parameter data of the holographic metasurface and the preset angle domain codebook structure information; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of each codeword are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship;

[0141] A multi-user angle domain scanning module 202 is used to simultaneously perform angle domain beam scanning on multiple users within the signal coverage range of the holographic metasurface based on a multi-user angle domain codebook;

[0142] A multi-user range domain codebook generation module 203, configured to generate a multi-user range domain codebook based on an angle set of multiple users obtained by beam scanning in the angle domain;

[0143] The multi-user range domain scanning module 204 is configured to perform range domain beam scanning on multiple users simultaneously based on a multi-user range domain codebook.

[0144] The multi-user angle domain codebook generation module 201 is used to determine the angle coverage area corresponding to each codeword in each codeword layer based on the preset angle domain codebook structure information and the signal coverage range of the holographic metasurface; calculate the value of each codeword based on the angle coverage area corresponding to each codeword and the parameter data of the holographic metasurface; and arrange the value of each codeword into a multi-user angle domain codebook according to the angle coverage area corresponding to each codeword in each codeword layer.

[0145] The preset angle domain codebook structure information includes the number of codeword layers, the first preset number and the recursive relationship;

[0146] The multi-user angle domain codebook generation module 201 is used to divide the signal coverage range of the holographic metasurface into an angle domain and a distance domain, perform a second preset number of equidistant sampling in the angle domain, and perform a third preset number of equidistant sampling in the distance domain to obtain multiple sampling coordinates; based on the number of codeword layers, the preset number, the recursive relationship and the sampling coordinates, the angle coverage area corresponding to each codeword in each codeword layer is determined respectively, and the angle coverage area corresponding to the codeword includes each sampling coordinate within the beam coverage range of the codeword.

[0147] The multi-user angle domain codebook generation module 201 is used to determine the beam gain corresponding to the first codeword at each sampling coordinate in the angle coverage area corresponding to the first codeword based on the angle coverage area corresponding to the first codeword; the first codeword is any codeword in each codeword; based on each sampling coordinate and the antenna unit information included in the parameter data of the holographic metasurface, a steering vector is calculated; based on the number of users and the antenna unit information included in the parameter data, a base station digital beamforming vector is calculated; based on the antenna unit information, an amplitude response of the antenna unit in the holographic metasurface is determined; based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit, the value of the first codeword is calculated.

[0148] The multi-user angle domain codebook generation module 201 is used to calculate the value of the first codeword by the following formula based on the beam gain, steering vector, base station digital beamforming vector and amplitude response of the antenna unit at each sampling coordinate of the first codeword;

[0149]

[0150] In the formula, m is the amplitude of the antenna unit, n is the serial number of the antenna unit, and m n is the amplitude of the nth antenna element; i is the sampling number in the angle domain of the signal coverage range, j is the sampling number in the distance domain of the signal coverage range, ψ i is the i-th sampling angle in the angle domain, μ j is the jth sampling distance in the distance domain; b(ψ i ,μ j ) is the sampling coordinate (ψ i ,μ j ), Where N is the total number of antenna units in the holographic metasurface, λ is the carrier wavelength, and r n is the sampling coordinate (ψ i ,μ j ) and the distance between the nth antenna unit, r is the sampling coordinate (ψ i ,μ j ) and the distance between the center point of the holographic metasurface;

[0151] v is the base station digital beamforming vector, Among them, P is the total power of the base station corresponding to the holographic metasurface, K is the number of users, and L is the number of feed sources of the holographic metasurface;

[0152] M is the amplitude response of the antenna unit, G i,j is the first codeword at the sampling coordinate (ψ i ,μ j ) beam gain, stGi,j is the first codeword at the sampling coordinate (ψ i ,μ j ) is a constraint function of the beam gain at ; the first codeword is the pth codeword in the sth layer, is the angular coverage area corresponding to the first codeword, and D is the value of the beam gain.

[0153] The multi-user angle domain scanning module 202 is used to adjust the amplitude of each antenna unit in the holographic metasurface based on the codewords in the first codeword layer in the multi-user angle domain codebook; the first codeword layer is any codeword layer among multiple codeword layers; send signals to the signal coverage range through the adjusted holographic metasurface, and receive the codeword sequence numbers fed back by each user within the signal coverage range; based on the codeword sequence numbers fed back by each user corresponding to each codeword layer, determine the angle of each user within the signal coverage range.

[0154] The multi-user distance domain codebook generation module 203 is used to determine the angles of each user with the same distance in the angle set based on the angle set of multiple users obtained by beam scanning in the angle domain; determine the codewords corresponding to the angles of each user with the same distance from the multi-user angle domain codebook; superimpose the codewords corresponding to the angles of each user with the same distance to obtain multi-beam codewords corresponding to different distances; and construct each multi-beam codeword into a multi-user distance domain codebook.

[0155] The multi-user distance domain codebook generation module 203 is used to obtain the multi-beam codewords corresponding to different distances through the following formula based on the codewords corresponding to the angles of each user with the same distance;

[0156]

[0157] In the formula, μ j is the jth sampling distance, k is the serial number of the user angle in the angle set, K is the total number of user angles in the angle set, ψ k is the kth user angle, m j is the multi-beam codeword corresponding to the jth sampling distance, m(ψ k ,μ j ) is the beam coverage coordinate (ψ k ,μ j ) codeword.

[0158] The multi-user distance domain scanning module 204 is used to adjust the amplitude of each antenna unit in the holographic metasurface based on the multi-user distance domain codebook; send signals to the signal coverage range through the adjusted holographic metasurface, and receive the codeword sequence number fed back by each user within the signal coverage range; and determine the distance of each user based on the distance domain range corresponding to the signal coverage range and the codeword sequence number fed back by each user.

[0159] The beam training device based on holographic metasurface provided in the above-mentioned embodiments of the present application and the beam training method based on holographic metasurface provided in the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0160] The present application also provides an electronic device to perform the above-mentioned beam training method based on holographic metasurface. Fig. 9 , which shows a schematic diagram of an electronic device provided by some embodiments of the present application. Fig. 9 As shown, the electronic device 10 includes: a processor 1000, a memory 1001, a bus 1002 and a communication interface 1003, and the processor 1000, the communication interface 1003 and the memory 1001 are connected via the bus 1002; the memory 1001 stores a computer program that can be run on the processor 1000, and the processor 1000 executes the method provided in any of the aforementioned embodiments of the present application when running the computer program.

[0161] The memory 1001 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 1003 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used.

[0162] The bus 1002 may be an ISA bus, a PCI bus, or an EISA bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory 1001 is used to store programs, and the processor 1000 executes the programs after receiving execution instructions. The method disclosed in any implementation of the aforementioned embodiment of the present application may be applied to the processor 1000, or implemented by the processor 1000.

[0163] The processor 1000 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 1000. The above processor 1000 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a readily available programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiments of the present application can be directly embodied as a hardware decoding processor to be executed, or the hardware and software modules in the decoding processor can be combined and executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1001, and the processor 1000 reads the information in the memory 1001 and completes the steps of the above method in combination with its hardware.

[0164] The electronic device provided in the embodiment of the present application and the beam training method based on holographic metasurface provided in the embodiment of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, operated or implemented therein.

[0165] The present application also provides a computer-readable storage medium corresponding to the beam training method based on the holographic metasurface provided in the above embodiment. Fig.10 The computer-readable storage medium shown is a CD 30 on which a computer program (ie, a program product) is stored. When the computer program is run by a processor, the method provided in any of the aforementioned embodiments is executed.

[0166] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical or magnetic storage media, which are not listed here one by one.

[0167] The computer-readable storage medium provided by the above-mentioned embodiments of the present application and the beam training method based on holographic metasurface provided by the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0168] An embodiment of the present application also provides a computer program product corresponding to the beam training method based on holographic metasurface provided in the aforementioned embodiment. The computer program product includes a computer program, which is executed by a processor to implement the method provided in the aforementioned embodiment.

[0169] The computer program product provided by the above-mentioned embodiments of the present application and the beam training method based on holographic metasurface provided by the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0170] It should be noted that:

[0171] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known structures and technologies are not shown in detail so as not to obscure the understanding of this description.

[0172] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be interpreted as reflecting the following schematic diagram: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the claims below, the inventive aspects are less than all the features of the single embodiment disclosed above. Therefore, the claims following the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0173] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0174] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A beam training method based on holographic metasurface, characterized in that: The method comprises: Based on the parameter data of the holographic metasurface and the preset angle domain codebook structure information, a multi-user angle domain codebook is generated; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of the codewords are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship; Based on the multi-user angle-domain codebook, simultaneously performing angle-domain beam scanning on multiple users within the signal coverage range of the holographic metasurface; Generate a multi-user range domain codebook based on the angle sets of the multiple users obtained by the beam scanning in the angle domain; Based on the multi-user range domain codebook, beam scanning in the range domain is performed on the multiple users simultaneously.

2. The method according to claim 1, characterized in that The method of generating a multi-user angle domain codebook based on parameter data of the holographic metasurface and preset angle domain codebook structure information includes: Based on the preset angle domain codebook structure information and the signal coverage range of the holographic metasurface, determining the angle coverage area corresponding to each codeword in each of the codeword layers; Based on the angular coverage area corresponding to each codeword and the parameter data of the holographic metasurface, respectively calculating the value of each codeword; According to the angle coverage area corresponding to each codeword in each codeword layer, the value of each codeword is arranged into the multi-user angle domain codebook.

3. The method according to claim 2, characterized in that The preset angle domain codebook structure information includes the number of codeword layers, the first preset number and the recursive relationship; The determining, based on the preset angle domain codebook structure information and the signal coverage range of the holographic metasurface, the angle coverage area corresponding to each codeword in each codeword layer comprises: Dividing the signal coverage range of the holographic metasurface into an angle domain and a distance domain, performing a second preset number of equidistant samplings in the angle domain, and performing a third preset number of equidistant samplings in the distance domain, to obtain a plurality of sampling coordinates; Based on the number of codeword layers, the preset number, the recursive relationship and the sampling coordinates, the angular coverage area corresponding to each codeword in each codeword layer is determined respectively, and the angular coverage area corresponding to the codeword includes each sampling coordinate within the beam coverage range of the codeword.

4. The method according to claim 2, characterized in that: The calculating the value of each codeword based on the angle coverage area corresponding to each codeword and the parameter data of the holographic metasurface includes: Based on the angular coverage area corresponding to the first codeword, determining the beam gain corresponding to each sampling coordinate in the angular coverage area corresponding to the first codeword; the first codeword is any one of the codewords; Calculating a steering vector based on the sampling coordinates and antenna unit information included in the parameter data of the holographic metasurface; Calculate a base station digital beamforming vector based on the number of users and the antenna unit information included in the parameter data; Based on the antenna unit information, determining an amplitude response of the antenna unit in the holographic metasurface; The value of the first codeword is calculated based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit.

5. The method according to claim 4, characterized in that The calculating the value of the first codeword based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the holographic beamformer includes: Calculate the value of the first codeword by the following formula based on the beam gain of the first codeword at each sampling coordinate, the steering vector, the base station digital beamforming vector and the amplitude response of the antenna unit; In the above formula, m is the amplitude of the antenna unit, n is the serial number of the antenna unit, and m n is the amplitude of the nth antenna element; i is the sampling number in the angle domain of the signal coverage range, j is the sampling number in the distance domain of the signal coverage range, ψ i is the i-th sampling angle in the angle domain, μ j is the jth sampling distance in the distance domain; b(ψ i ,μ j ) is the sampling coordinate (ψ i ,μ j ), Where N is the total number of antenna units in the holographic metasurface, λ is the carrier wavelength, r n is the sampling coordinate (ψ i ,μ j ) and the distance between the nth antenna unit, r is the sampling coordinate (ψ i ,μ j ) and the distance between the center point of the holographic metasurface; v is the base station digital beamforming vector, Wherein, P is the total power of the base station corresponding to the holographic metasurface, K is the number of users, and L is the number of feed sources of the holographic metasurface; M is the amplitude response of the antenna unit, G i,j The first codeword is at the sampling coordinate (ψ i ,μ j ) beam gain, stG i,j The first codeword is at the sampling coordinate (ψ i ,μ j ) at a beam gain constraint function; the first codeword is the p-th codeword in the s-th layer, is the angular coverage area corresponding to the first codeword, and D is the value of the beam gain.

6. The method according to any one of claims 1 to 5, characterized in that: The method of simultaneously performing angle-domain beam scanning on multiple users within the signal coverage range of the holographic metasurface based on the multi-user angle-domain codebook includes: Based on the codewords in the first codeword layer in the multi-user angle domain codebook, adjusting the amplitude of each antenna unit in the holographic metasurface; the first codeword layer is any codeword layer in the multiple codeword layers; Sending a signal to the signal coverage range through the adjusted holographic metasurface, and receiving a codeword sequence number fed back by each user within the signal coverage range; Based on the codeword sequence numbers fed back by the users corresponding to the codeword layers, the angles at which the users are located within the signal coverage are determined respectively.

7. The method according to any one of claims 1 to 5, characterized in that: The generating a multi-user range domain codebook based on the angle sets of the multiple users obtained by the beam scanning in the angle domain includes: Determine the angles of the plurality of users obtained based on the beam scanning in the angle domain, and determine the angles of each user having the same distance in the angle set; Determining, from the multi-user angle domain codebook, codewords corresponding to the user angles having the same distance; The codewords corresponding to the user angles with the same distance are superimposed to obtain multi-beam codewords corresponding to different distances; The multi-beam codewords are constructed into the multi-user range domain codebook.

8. The method according to claim 7, characterized in that The codewords corresponding to the user angles with the same distance are superimposed to obtain multi-beam codewords corresponding to different distances, including: Based on the codewords corresponding to the angles of each user at the same distance, the multi-beam codewords corresponding to different distances are obtained by the following formula; In the above formula, μ j is the jth sampling distance, k is the sequence number of the user angle in the angle set, K is the total number of user angles in the angle set, ψ k is the kth user angle, m j is the multi-beam codeword corresponding to the jth sampling distance, m(ψ k ,μ j ) is the beam coverage coordinate (ψ k ,μ j ) codeword.

9. The method according to claim 1, characterized in that: The simultaneously performing range-domain beam scanning on the multiple users based on the multi-user range-domain codebook includes: Based on a multi-user range domain codebook, adjusting the amplitude of each antenna unit in the holographic metasurface; Sending a signal to the signal coverage range through the adjusted holographic metasurface, and receiving a codeword sequence number fed back by each user within the signal coverage range; Based on the distance domain range corresponding to the signal coverage range and the codeword sequence number fed back by each user, the distance of each user is determined respectively.

10. A beam training device based on a holographic metasurface, characterized in that: The device comprises: A multi-user angle domain codebook generation module is used to generate a multi-user angle domain codebook based on parameter data of a holographic metasurface and preset angle domain codebook structure information; the multi-user angle domain codebook includes a plurality of codeword layers arranged in sequence, each codeword layer includes a first preset number of codewords, the first preset number is a positive integer greater than 1, each codeword in the same codeword layer includes at least one continuous angle coverage area and the angle coverage areas of the codewords are arranged at intervals, and the angle coverage areas of the same codeword in two adjacent codeword layers in the plurality of codeword layers have a recursive relationship; A multi-user angle domain scanning module, configured to simultaneously perform angle domain beam scanning on multiple users within the signal coverage range of the holographic metasurface based on the multi-user angle domain codebook; A multi-user range domain codebook generation module, configured to generate a multi-user range domain codebook based on the angle sets of the multiple users obtained by beam scanning in the angle domain; A multi-user range domain scanning module is used to simultaneously perform range domain beam scanning on the multiple users based on the multi-user range domain codebook.

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