A method and system for high-order secure signal communication based on phased metasurface

Abstract

This invention discloses a method and system for high-order signal secure communication based on a phased metasurface, relating to the field of power security communication technology. It includes a phased metasurface-based communication transmitter architecture. By performing spatiotemporal coding on the metasurface units, a preset high-order signal is synthesized in the far field. In the desired direction, the signal constellation diagram only experiences proportional amplitude scaling, while signals in undesired directions exhibit varying degrees of distortion based on changes in the spatiotemporal coding pattern. This invention, based on a phased metasurface, directly achieves high-order signal modulation through spatial coding and improves the security of the signal's physical layer through temporal coding.

Description

Technical Field

[0001] This invention relates to the field of power safety communication technology, and in particular to a method and system for realizing high-order signal security communication based on phased metasurface. Background Technology

[0002] Existing communication transmitter systems based on phase-tunable metasurfaces can directly modulate baseband data onto a carrier signal illuminating the metasurface by adjusting the metasurface's reflection or transmission coefficients. The signal after reflection or transmission through the metasurface is the conventional radio frequency signal with amplitude-phase modulation. Recent work in this field indicates that, due to the coupling limitations of amplitude-phase modulation, designing metasurface units capable of independently and precisely controlling the amplitude and phase of the incident wave is extremely difficult. Although some published works have achieved independent amplitude and phase control, their control range and accuracy are not ideal, making them unsuitable for direct modulation of higher-order signals. Designing digitally coded metasurfaces with only phase-tunable reflection or transmission coefficients is relatively easier.

[0003] Based on a 2-bit phase-controlled metasurface, Zhang.L et al. proposed a spatiotemporal coding scheme in reference [1] and built a multi-channel direct information transmission system. By optimizing the spatial pattern of the metasurface array and performing periodic sequence coding on each unit, the scheme can independently transmit information to users in different preset spatial directions in different frequency bands, while the signal in the undesired direction will be distorted, which has a certain degree of confidentiality. First, since the scheme introduces a time-dimensional algorithm, the metasurface unit needs to be periodically controlled multiple times for each symbol transmitted, which greatly reduces the modulation efficiency of the electronic control device and wastes the control performance of the device; second, the signal transmitted to the user is an OOK signal, which has low spectrum utilization and low communication rate; finally, the signal beamwidth in the desired direction is large, and when the eavesdropper is in certain specific directions or close to the desired direction, the signal may still be eavesdropped. In the communication transmitter architecture based on metasurface, improving the spectrum utilization of the modulated signal and the modulation efficiency of the electronic control element in the metasurface unit is the key to realizing high-speed communication. In secure communication, increasing the distortion of the signal in the undesired direction is the key to improving the confidentiality performance. Summary of the Invention

[0004] In view of the problems existing in the current high-order signal secure communication and system based on phased metasurface, this invention is proposed.

[0005] Therefore, the problem that this invention aims to solve is: poor security and low communication rate, which wastes the control performance of the device.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, embodiments of the present invention provide a method for realizing high-order secure signal communication based on phased-array metasurfaces, which includes the following steps.

[0008] Construct a metasurface subarray consisting of L×L periodically arranged 2-bit phased array units;

[0009] Set a random sequence S, and combine X subsets with each N rows of metasurface units as the basic set. All subsets form a subset space A.

[0010] By traversing all the permutations and combinations of phase modulation states among subsets in subset space A, M spatial coding patterns can be obtained, and a mapping table P1 is established between the spatial coding patterns obtained from all subsets in subset space A and the preset M-order signal symbols.

[0011] Each N columns of metasurface units are combined into Y subsets, and all subsets form a subset space B.

[0012] By traversing all the permutations and combinations of phase modulation states among subsets in subset space B, M spatial coding patterns can be obtained, and a mapping table P2 is established between the spatial coding patterns obtained from all subsets in subset space B and the preset M-order signal symbols.

[0013] Repeatedly send the symbols of the information symbol sequence until transmission is complete.

[0014] As a preferred embodiment of the high-order signal secure communication method based on phased metasurfaces described in this invention, the pre-synthesized QAM signal has an order of M, where M is greater than 8 and is a power of 2. The relationship between L and M is expressed as follows:

[0015]

[0016] in, This indicates the rounding up operation. The metasurface array consists of N×N of the above metasurface subarrays, where N can be any positive integer.

[0017] As a preferred embodiment of the high-order signal secure communication method based on phased metasurface described in this invention, the random sequence S has a length of l and contains both digits 0 and 1, where l is any integer greater than 1.

[0018] As a preferred embodiment of the high-order signal secure communication method based on phased metasurfaces described in this invention, wherein: the subset space A contains all subsets composed of basic sets, and the combination method is as follows:

[0019] When log2M is even, arbitrarily partition 2 k-1 From the undivided basic set to the k-th subset A k Inside,

[0020] When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 From the undivided basic set to the k-th subset A k Inside.

[0021] As a preferred embodiment of the high-order secure signal communication method based on phased metasurfaces described in this invention, wherein: the subset space B contains all subsets composed of basic sets, and the combination method is as follows:

[0022] When log2M is even, sub-step 6.1: arbitrarily partition 2 k-1 The unpartitioned basic sets are incorporated into the k-th subset Bk.

[0023] When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 The undivided basic set is incorporated into the k-th subset Bk.

[0024] As a preferred embodiment of the high-order signal secure communication method based on phased metasurface described in this invention, wherein: when transmitting the symbol of the information symbol sequence, the information symbol sequence to be transmitted is I with a length of Q; when the length of the random sequence S is less than I, the random sequence S is periodically extended to obtain the sequence S1, the length of the sequence S1 is W, W cannot be less than the length of the information symbol sequence I, and WQ consecutive elements are deleted from the sequence S1.

[0025] Align the 0 and 1 elements in the information symbol sequence and the random sequence S1;

[0026] Initialize t to 1 to represent the t-th symbol;

[0027] When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 0, execute the first-level step;

[0028] When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 1, the second-level step is executed.

[0029] t = t + 1, repeat this step until all symbols of the information symbol sequence have been sent.

[0030] As a preferred embodiment of the high-order signal secure communication method based on phased metasurface described in this invention, the first-level step is: according to the symbol to be transmitted, by looking up the mapping relationship table P1, the phase modulation state of the metasurface unit is adjusted so that the preset symbol can be synthesized in the far field of the metasurface normal.

[0031] The secondary step is as follows: based on the symbol to be transmitted, by looking up the mapping table P2, the phase modulation state of the metasurface unit is adjusted, and the preset symbol can be synthesized in the far field of the metasurface normal.

[0032] Secondly, embodiments of the present invention provide a high-order signal secure communication system based on a phased metasurface, which includes a metasurface construction module, an encoding pattern generation module, a random sequence processing module, and an information symbol transmission control module;

[0033] The metasurface construction module constructs an L×L metasurface subarray composed of 2-bit phased arrays and an N×N metasurface subarray composed of metasurface arrays.

[0034] The coding pattern generation module traverses subsets in subset spaces A and B, generates spatial coding patterns, and establishes a mapping table between spatial coding patterns and M-order signal symbols.

[0035] The random sequence processing module is used for the generation and periodic extension of the random sequence S;

[0036] The information symbol transmission control module is used to control the symbol transmission of the information symbol sequence.

[0037] Thirdly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement any of the steps of the above-described method for realizing high-order signal secure communication based on phased metasurface.

[0038] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any of the steps of the above-described method for realizing high-order signal secure communication based on phased metasurfaces.

[0039] The beneficial effects of this invention are:

[0040] 1. The method provided by this invention is applicable to both reflective and transmissive metasurfaces, and has universality for metasurface communication transmitter systems with 2-bit phase modulation capability.

[0041] 2. The high-order signal synthesis method proposed in this invention does not require periodic time-domain coding. For each symbol transmitted, only a few electronic control elements of each unit need to be adjusted at most once, which realizes high-efficiency utilization of the unit electronic control devices and improves the spectrum utilization rate.

[0042] 3. The high-order signal synthesis method proposed in this invention has the characteristics of directional modulation technology. It introduces a random sequence S. In different symbol periods, the same symbol may correspond to different spatial coding patterns. By utilizing the orthogonality of the demodulation directions of the signal beams generated by different spatial coding patterns in space, the demodulation beam range of the signal in continuous time is reduced. The receiver keeps the magnitude of the error vector (EVM) in the desired communication direction to a minimum. While ensuring the maximum signal quality in the desired direction, it effectively scrambles or hides signals that deviate from the desired communication direction.

[0043] 4. This method utilizes the characteristic of metasurfaces that can modulate the phase of the incident signal without changing the signal amplitude. Through spatial coding, a higher-order signal is synthesized in the far-field region of the metasurface. Through time coding, the spatial direction of the correctly demodulated signal is changed, ensuring that the signal can be continuously demodulated without distortion only in the intersection of the demodulated directions. Each change in the spatial pattern of the metasurface array transmits a corresponding higher-order symbol, realizing efficient utilization of the control performance of the metasurface electronic components and improving spectrum utilization. This method has the same confidentiality characteristics as traditional directional modulation; eavesdroppers may still be able to eavesdrop on the signal in certain specific directions or near the desired communication direction. However, this scheme introduces a random sequence S to dynamically change the spatial distribution of the beam, preventing eavesdroppers from continuously eavesdropping on the signal and allowing them to eavesdrop on only portions of the signal in certain specific directions, thus improving the confidentiality of communication. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0045] Figure 1 This is a structural diagram of a high-order secure signal communication method based on phased metasurfaces.

[0046] Figure 2 This is a schematic diagram of a 3×3 metasurface array for realizing a high-order signal secure communication method based on phased metasurfaces.

[0047] Figure 3 This refers to the metasurface array spatial coding pattern corresponding to different symbol symbols in subset space A of the high-order signal secure communication method based on phased metasurfaces.

[0048] Figure 4 This refers to the metasurface array spatial coding pattern corresponding to different symbol symbols in subset space B of a high-order signal secure communication method based on phased metasurfaces.

[0049] Figure 5 This is a signal constellation diagram synthesized in the far field in a preset direction for a high-order signal secure communication method based on phased metasurfaces.

[0050] Figure 6 To realize a high-order signal secure communication method based on phased metasurfaces, a signal constellation diagram is synthesized from spatial coding patterns of different subsets deviating from the desired direction.

[0051] Figure 7 The simulation diagram shows the distortion distribution of the EVM of the signal constellation points synthesized from different subsets of spatial coding patterns deviating from the desired direction, in order to realize a high-order signal secure communication method based on phased metasurface.

[0052] Figure 8 This is a diagram showing the spatial coding pattern changes of 16 symbol elements in chronological order for a high-order secure signal communication method based on phased metasurfaces. Detailed Implementation

[0053] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0054] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0055] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0056] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0057] In the description of the present invention, it should be noted that the terms "upper, lower, inner, and outer" and other references to orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first, second, or third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0059] Example 1

[0060] Reference Figures 1 to 8 This is the first embodiment of the present invention, which provides a method for realizing high-order secure signal communication based on phased metasurfaces, including the following steps:

[0061] S1. Construct a metasurface subarray consisting of L×L periodically arranged 2-bit phased array units.

[0062] The pre-synthesized QAM signal has an order of M, where M is greater than 8 and is a power of 2. The relationship between L and M is expressed as follows:

[0063]

[0064] in, This indicates the rounding up operation. The metasurface array consists of N×N of the above metasurface subarrays, where N can be any positive integer.

[0065] S2. Set a random sequence S, and combine it into X subsets with each N rows of metasurface units as the basic set. All subsets form a subset space A.

[0066] The random sequence S is of length l and contains both digits 0 and 1, where l is any integer greater than 1.

[0067] In the example, a random sequence S = {0,1,1,1,0,1,0,0,1,0} of length 10 is generated.

[0068] S3. By traversing all the permutations and combinations of phase modulation states among subsets in subset space A, M spatial coding patterns can be obtained, and a mapping table P1 is established between the spatial coding patterns obtained from all subsets in subset space A and the preset M-order signal symbols.

[0069] The subset space A contains all subsets composed of basic sets, and the combination methods are as follows:

[0070] When log2M is even, arbitrarily partition 2 k-1 From the undivided basic set to the k-th subset A k Inside,

[0071]

[0072] When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 From the undivided basic set to the k-th subset A k Inside.

[0073] In the embodiment, each row of metasurface units is used as the basic set to form two subsets. All subsets form a subset space A. Since log2M = 4 is an even number, the first basic set (the first row of metasurface units) is divided into the first subset A1, and the remaining two undivided basic sets (the second and third rows of metasurface units) are divided into the second subset A2.

[0074] Within a symbol period, all 2-bit phase-independent controllable units within each subset of subset A maintain the same phase modulation state. A combination of phase modulation states among subsets is called a spatial coding pattern. By traversing all permutations of phase modulation states among subsets in subset space A, 16 spatial coding patterns can be obtained, such as... Figure 3 As shown.

[0075] Table 1: Mapping relationship between spatial coding patterns obtained from establishing all subsets in subset space A and preset 16th-order signal symbols.

[0076]

[0077]

[0078] S4. Each N columns of metasurface units are used as the basic set to form Y subsets, and all subsets form the subset space B.

[0079] Each column of metasurface units is used as a basic set to form two subsets, and all subsets form a subset space B. Since log2M = 4 is an even number, the first basic set (the first column of metasurface units) is allocated to the first subset B1, and the remaining two basic sets (the second and third columns of metasurface units) are allocated to the second subset B2.

[0080] S5. By traversing all the permutations and combinations of phase modulation states among subsets in subset space B, M spatial coding patterns can be obtained, and a mapping table P2 is established between the spatial coding patterns obtained from all subsets in subset space B and the preset M-order signal symbols.

[0081] Subset space B contains all subsets composed of the basic sets, and the combination methods are as follows:

[0082] When log2M is even, sub-step 6.1: arbitrarily partition 2 k-1 The unpartitioned basic sets are incorporated into the k-th subset Bk.

[0083] When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 The undivided basic set is incorporated into the k-th subset Bk.

[0084] Within a symbol period, all 2-bit phase-independent controllable units within each subset of subset space B maintain the same phase modulation state. A combination of phase modulation states among subsets is called a spatial coding pattern. By traversing all permutations of phase modulation states among subsets in subset space B, 16 spatial coding patterns can be obtained, such as... Figure 4 As shown.

[0085] Table 2: Mapping relationship between spatial coding patterns obtained from establishing all subsets in subset space B and preset 16th-order signal symbols.

[0086]

[0087] S6. Repeatedly send the symbols of the information symbol sequence until the transmission is complete.

[0088] When sending the symbol of the information symbol sequence, the information symbol sequence to be sent is I with a length of Q. When the length of the random sequence S is less than I, the random sequence S is periodically extended to obtain the sequence S1. The length of the sequence S1 is W, and W cannot be less than the length of the information symbol sequence I. WQ consecutive elements are deleted from the sequence S1.

[0089] Align the 0 and 1 elements in the information symbol sequence and the random sequence S1;

[0090] Initialize t to 1 to represent the t-th symbol;

[0091] When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 0, execute the first-level step;

[0092] When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 1, the second-level step is executed.

[0093] t = t + 1, repeat this step until all symbols of the information symbol sequence have been sent.

[0094] The first-level step is as follows: based on the symbol to be transmitted, by looking up the mapping relationship table P1, the phase control state of the metasurface unit is adjusted so that the preset symbol can be synthesized in the far field of the metasurface normal.

[0095] The secondary step is as follows: based on the symbol to be transmitted, by looking up the mapping table P2, the phase modulation state of the metasurface unit is adjusted, and the preset symbol can be synthesized in the far field of the metasurface normal.

[0096] In this embodiment, the information symbol sequence to be sent is I = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}. The length of the random sequence S is 10, which is shorter than the information symbol sequence I. Therefore, the random sequence S is periodically extended once, and 4 elements are deleted from the end to obtain the sequence S1 = {0,1,1,1,0,1,0,0,1,0,0,1,1,1,0,1}. The information symbol symbols and the 0 and 1 elements in the random sequence S1 are aligned, and the correspondence is shown in Table 3. Let t = 1.

[0097] Table 3: Correspondence Table

[0098] t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Random sequence S1 0 1 1 1 0 1 0 0 1 0 0 1 1 1 0 1 Symbol sequence I 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

[0099] When the first information symbol is sent, the corresponding random sequence S1 has an element of 0, and the symbol to be transmitted is 0. By looking up the mapping table 1, the phase state of the metasurface unit is adjusted, and the preset symbol is synthesized in the preset direction.

[0100] Let t = t + 1, the spatial coding patterns corresponding to all 10 symbolic elements to be transmitted are as follows: Figure 7 As shown.

[0101] A pre-defined 16th-order QAM signal can be synthesized in the normal direction of a far-field array using a communication transmitter system based on a metasurface with 2-bit phase modulation capability; the signal constellation diagram synthesized at different times deviating from the normal direction is shown below. Figure 6 As shown in the simulation diagram, the distortion distribution of the synthesized signal EVM at different times and directions is as follows: Figure 7As shown, in this embodiment, the spatial coding pattern changes of all 16 symbolic units to be transmitted in chronological order are as follows: Figure 8 As shown.

[0102] In summary, this method leverages the characteristic of metasurfaces that can modulate the phase of the incident signal without altering its amplitude. Through spatial coding, a higher-order signal is synthesized in the far-field region of the metasurface. Time coding alters the spatial direction of the correctly demodulated signal, ensuring continuous, distortion-free demodulation only along the intersection of the demodulated directions. Each change in the spatial pattern of the metasurface array transmits a corresponding higher-order symbol, achieving efficient utilization of the metasurface's electronic control components and improving spectral efficiency. While this method retains the same confidentiality characteristics as traditional directional modulation—eavesdroppers might still be able to eavesdrop in certain directions or near the desired communication direction—this scheme introduces a random sequence S to dynamically change the spatial distribution of the beam, preventing eavesdroppers from continuously eavesdropping and limiting their access to portions of the signal in specific directions, thus enhancing communication confidentiality.

[0103] Example 2

[0104] Based on the first embodiment, this embodiment further provides a high-order signal secure communication system based on a phased metasurface, including a metasurface construction module, an encoding pattern generation module, a random sequence processing module, and an information symbol transmission control module;

[0105] The metasurface construction module constructs an L×L metasurface subarray composed of 2-bit phased arrays and an N×N metasurface subarray composed of metasurface arrays.

[0106] The coding pattern generation module traverses subsets in subset spaces A and B, generates spatial coding patterns, and establishes a mapping table between spatial coding patterns and M-order signal symbols.

[0107] The random sequence processing module is used for the generation and periodic extension of the random sequence S;

[0108] The information symbol transmission control module is used to control the symbol transmission of the information symbol sequence.

[0109] This embodiment also provides a computer device applicable to the implementation of a high-order signal secure communication method based on a phased metasurface, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the high-order signal secure communication method based on a phased metasurface as proposed in the above embodiment.

[0110] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0111] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the method for high-order signal secure communication based on phased metasurfaces as proposed in the above embodiments.

[0112] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. Technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for high-order secure signal communication based on phased metasurfaces, characterized in that: Includes the following steps, Construct a metasurface subarray consisting of L×L periodically arranged 2-bit phased array units; Set a random sequence S, and combine X subsets with each N rows of metasurface units as the basic set. All subsets form a subset space A. By traversing all the permutations and combinations of phase modulation states among subsets in subset space A, M spatial coding patterns can be obtained, and a mapping table P1 is established between the spatial coding patterns obtained from all subsets in subset space A and the preset M-order signal symbols. Each N columns of metasurface units are combined into Y subsets, and all subsets form a subset space B. By traversing all the permutations and combinations of phase modulation states among subsets in subset space B, M spatial coding patterns can be obtained, and a mapping table P2 is established between the spatial coding patterns obtained from all subsets in subset space B and the preset M-order signal symbols. Repeatedly send the symbols of the information symbol sequence until transmission is complete; The pre-synthesized QAM signal has an order of M, where M is greater than 8 and is a power of 2. The relationship between L and M is expressed as follows: in, This indicates the rounding up operation. The metasurface array consists of N×N subarrays of the above metasurface, where N can be any positive integer. The random sequence S is of length l and contains both digits 0 and 1, where l is any integer greater than 1; The subset space A contains all subsets composed of basic sets, and the combination methods are as follows: When log2M is even, arbitrarily partition 2 k-1 From the undivided basic set to the k-th subset A k Inside, When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 From the undivided basic set to the k-th subset A k Inside; Subset space B contains all subsets composed of the basic sets, and the combination methods are as follows: When log2M is even, sub-step 6.1: arbitrarily partition 2 k-1 The unpartitioned basic sets are incorporated into the k-th subset Bk. When log₂M is odd, both the first and second subsets are partitioned into one unpartitioned basic set, resulting in a 3×2 partition. k-3 The undivided basic sets are divided into the k-th subset Bk; When sending the symbol of the information symbol sequence, the information symbol sequence to be sent is I with a length of Q. When the length of the random sequence S is less than I, the random sequence S is periodically extended to obtain the sequence S1. The length of the sequence S1 is W, and W cannot be less than the length of the information symbol sequence I. WQ consecutive elements are deleted from the sequence S1. Align the 0 and 1 elements in the information symbol sequence and the random sequence S1; Initialize t to 1 to represent the t-th symbol; When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 0, execute the first-level step; When the element in the random sequence S1 corresponding to the t-th information symbol to be transmitted is 1, the second-level step is executed. t = t + 1, repeat this step until all symbols of the information symbol sequence have been sent; The first-level step is as follows: based on the symbol to be transmitted, by looking up the mapping relationship table P1, the phase control state of the metasurface unit is adjusted so that the preset symbol can be synthesized in the far field of the metasurface normal. The secondary step is as follows: based on the symbol to be transmitted, by looking up the mapping table P2, the phase modulation state of the metasurface unit is adjusted, and the preset symbol can be synthesized in the far field of the metasurface normal.

2. A high-order signal secure communication system based on a phased metasurface, based on the high-order signal secure communication method based on a phased metasurface as described in claim 1, characterized in that: It includes a metasurface construction module, an encoding pattern generation module, a random sequence processing module, and an information symbol transmission control module; The metasurface construction module constructs an L×L metasurface subarray composed of 2-bit phased arrays and an N×N metasurface subarray composed of metasurface arrays. The coding pattern generation module traverses subsets in subset spaces A and B, generates spatial coding patterns, and establishes a mapping table between spatial coding patterns and M-order signal symbols. The random sequence processing module is used for the generation and periodic extension of the random sequence S; The information symbol transmission control module is used to control the symbol transmission of the information symbol sequence.

3. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the method for realizing high-order signal secure communication based on phased metasurface as described in claim 1.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the method for realizing high-order signal secure communication based on phased metasurface as described in claim 1.

Images