High-efficiency low-computing-power physical layer security communication method and device based on intelligent metasurface and medium

Abstract

The application discloses a high-efficiency low-computing-power physical layer security communication method and device based on an intelligent metasurface and a medium, and comprises the following steps: S1, inputting a channel matrix h1 and H2 among a base station, a desired user and an eavesdropper; S2, setting an iteration number I, and initializing the iteration number i=0 and u (0) ; S3, randomly generating S candidate RIS phase shift matrices according to u i ; S4, obtaining an equivalent channel matrix according to the channel matrix h1 and the candidate RIS phase shift matrix, and calculating a corresponding precoding matrix W; S5, calculating a maximum achievable secure rate of each candidate RIS phase shift matrix according to the equivalent channel matrix, the channel matrix H2 and the precoding matrix W; S6, arranging the candidate RIS phase shift matrices Θ in descending order of the maximum achievable secure rate; S7, selecting S' "elite" RIS phase shift matrices Θ with the maximum secure rate; S8, updating u (i+1) based on the selected S' "elite" RIS phase shift matrices Θ; and S9, outputting a quasi-optimal RIS phase shift matrix Θ, so as to realize high-efficiency low-computing-power physical layer security communication.

Description

TECHNICAL FIELD

[0001] The application relates to a high-efficiency low-computing-power physical layer security communication method, device and medium based on an intelligent metasurface, and relates to the field of communication. BACKGROUND

[0002] Due to the openness of a wireless channel used in mobile communication, security problems such as eavesdropping interference and illegal access exist in the process, which will bring serious threats. Traditional security communication technology is mainly based on a key system and is implemented in an upper layer of a communication network. However, in some network structures, the management and distribution of keys will become very complex or difficult to implement, for example, in a distributed system, there is no central node, and the distribution of keys cannot be performed. In addition, in the Internet of Things, there are many simple devices that cannot implement encryption and decryption functions. With the continuous improvement of computer computing performance, the cost required to crack a key is becoming lower and lower. Under such a background, the research on new security communication technology becomes crucial.

[0003] As a new security communication technology, physical layer security uses the characteristics of wireless channels and physical layer technology to achieve secure transmission of wireless communication. Physical layer security technology does not rely on computational complexity, and even if the other party has strong computing power, it cannot harm the security of wireless transmission. With the gradual rise of the role of physical layer security in the field of information security, the research of physical layer security has become a research hotspot in the field of wireless communication. Reconfigurable Intelligent Surface (RIS) as an emerging technology, is showing great application potential in the field of physical layer security. RIS is composed of a large number of sub-wavelength electromagnetic units, which can dynamically control the amplitude, phase and polarization of electromagnetic waves. By inputting different excitation controls, the incident electromagnetic waves can be flexibly manipulated on demand, from passive adaptation to active construction of complex electromagnetic environments. In the application of physical layer security, on the one hand, RIS can effectively enhance the confidentiality of communication. In traditional communication, signals are easy to be eavesdropped, while RIS can adjust electromagnetic parameters to make the legitimate receiving end receive strong signals, while forming signal nulls or weak signal areas at the location of the eavesdropper, greatly reducing the risk of information leakage. For example, in a rich indoor environment, RIS can reflect and refract signals to confuse the eavesdropper's acquisition path of the original signal. On the other hand, RIS helps to improve the anti-interference ability of communication. In the face of malicious interference from the outside world, it can quickly change the electromagnetic propagation mode, direct the interference signal to harmless areas, and protect the stability and reliability of the legitimate communication link, ensuring that information can be accurately and correctly transmitted from the sender to the receiver. The mainstream implementation of RIS is to use PIN diodes to control the polarization, scattering and focusing of electromagnetic waves. PIN diodes have two states of switching corresponding to 0 and π phase shift, low device cost and low energy consumption, which helps to realize large-scale RIS arrays.

[0004] At present, the physical layer security algorithm technology based on RIS is developing rapidly, and the core technology principles and mechanisms of RIS are as follows Figure 1The RIS reconstructs the propagation characteristics of the wireless channel by dynamically regulating the phase and amplitude of electromagnetic waves, forms a controllable reflected / transmitted beam, and enhances the difference between the legal channel and the eavesdropping channel. Its core capabilities include: 1) Channel randomness enhancement: by adjusting the phase shift matrix in real time, the channel correlation of the eavesdropper is destroyed; 2) Spatial degree of freedom expansion: multiple RIS cooperation can build a virtual MIMO system, which significantly improves the security capacity. The core technology security performance indicators based on RIS: 1) Achievable security rate (SR): maximize the signal-to-noise ratio difference between the legitimate user and the eavesdropper by optimizing the phase shift matrix; 2) Security outage probability (SOP): dynamically adjust the RIS configuration using channel state information to ensure that the eavesdropping channel quality is below the threshold. Classification of typical physical layer security algorithms based on RIS: beamforming optimization algorithm - hybrid beamforming: STAR-RIS technology realizes independent regulation of reflected / transmitted beams, which makes the security rate in the NOMA system increase by 30%. Joint phase shift optimization: use particle swarm optimization (PSO) to optimize the RIS phase shift parameters to achieve 1 bit / (channel use) security gain; Dynamic resource allocation algorithm - UAV trajectory - RIS joint optimization: based on deep reinforcement learning (DDQN) 3D trajectory planning, the security rate is improved by 45% compared with the traditional SCA algorithm. Multi-RIS selection algorithm: through link capacity pre-screening, the optimal RIS subset is selected, and the transmission complexity is reduced by 40%; Intelligent optimization algorithm - AI-enabled dynamic encryption: use neural networks to generate phase shift strategies in real time to cope with fast time-varying channel environments.

[0005] One of the main drawbacks of existing physical layer security technologies is the complexity of multi-user scenarios. When the Internet of Things is accessed on a large scale, the computational complexity of the RIS selection algorithm increases exponentially; there is a lack of effective defense models for eavesdropper cooperative attack scenarios. In multi-standard, multi-band hybrid networking scenarios (such as NOMA, MIMO systems), RIS needs to adapt to different communication protocols and hardware architectures to ensure cross-layer security cooperation; channel state information (CSI) errors can significantly reduce security performance, and robust algorithms (such as based on bounded uncertainty models) need to be designed to cope with channel estimation bias. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, in order to solve the above problems, the purpose of the present application is to provide an efficient and low-power physical layer security communication method, device and medium based on intelligent metasurface, which can improve the physical layer security communication capacity.

[0007] In order to achieve the above application purpose, the technical scheme adopted by the present application is:

[0008] In a first aspect, the present application provides an efficient and low-power physical layer security communication method based on intelligent metasurface, comprising:

[0009] S1, input the channel matrix h1, h2 between the base station and the desired user, the eavesdropper;

[0010] S2, set the iteration number I, and initialize the iteration number i = 0 and u (0) , wherein u (0) is a one-dimensional vector, the dimension is consistent with the number of array units of the RIS;

[0011] S3, according to u i , randomly generate S candidate RIS phase shift matrices;

[0012] S4, according to the channel matrix h1 and the candidate RIS phase shift matrix, obtain the equivalent channel matrix, and calculate the corresponding precoding matrix W;

[0013] S5, according to the equivalent channel matrix and the channel matrix H2 and the precoding matrix W, calculate the maximum achievable secure rate of each candidate RIS phase shift matrix;

[0014] S6, arrange the candidate RIS phase shift matrix Θ in descending order according to the maximum achievable secure rate;

[0015] S7, select S' "elite" RIS phase shift matrices Θ with the maximum secure rate;

[0016] S8, update u (i+1) based on the selected S' "elite" RIS phase shift matrix Θ, set i = i + 1, return to step S3 until i = I is finished;

[0017] S9, output the quasi-optimal RIS phase shift matrix Θ for realizing high-performance and low-computing-power physical layer security communication.

[0018] In some possible implementation manners, u (0) = 1 / 2 x 1 N×1 , each element in the vector is a probability value representing the initial probability of generating 0 phase shift for the corresponding array unit, and the initial probability is obtained by generating a random number in a uniform distribution of [0, 1], wherein the number of reflection units on the RIS is N.

[0019] In some possible implementation manners, according to u i , S candidate RIS phase shift matrices are randomly generated, including:

[0020] According to the probability of 0 phase shift corresponding to each element in u i , the phase shift of the array unit on the corresponding RIS is randomly generated, and the phase shift of each array unit is placed in the diagonal element of the matrix Θ one by one, keeping the non-diagonal elements as 0 unchanged, to form the phase shift matrix.

[0021] In some possible implementation manners, the equivalent channel refers to a sum of channels of all signal passing paths of the base station and the user, and is defined as h eq =h1+rΘG, wherein r is a channel between the RIS and the receiver, and G is a channel between the base station and the RIS.

[0022] In some possible implementation manners, the precoding matrix is used to improve the strength of the signal received by the user and reduce the strength of the signal received by the eavesdropper, and the precoding matrix W = h eq H (h eq h eq H ) -1 .

[0023] In some possible implementation manners, the maximum achievable secure rate of each candidate RIS phase shift matrix is calculated: C (Θ) = C1-C2, C1 = log2|1+ρhWss H W H h H |; C2 = log2|1+ρH2Wss H W H H2 H |; wherein, s represents a transmission signal vector, s H is a conjugate transpose of the transmission signal vector, H2 represents a channel between the base station and the eavesdropper, and H2 H represents a conjugate transpose of H2.

[0024] In some possible implementation manners, the u (i+1) The specific process is: minimizing the cross entropy obtained by u i The cross entropy between the "elite" RIS phase shift matrix and the RIS phase shift matrix generated this time u (i+1) The formula for minimizing the cross entropy is as follows:

[0025]

[0026] wherein q (Θ s ; u (i) ) represents the probability of generating Θ s corresponding to each element being 0.

[0027] In a second aspect, the present application also provides an electronic device, comprising: at least one processor; and a memory connected with the processor in communication; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor to enable the processor to execute the method.

[0028] In a third aspect, the present application also provides a computer readable storage medium storing one or more programs, the one or more programs comprising instructions for causing a computer to perform the method.

[0029] The present application has the following characteristics due to the above technical solutions: at present, RIS physical layer security algorithms have not been developed on a large scale, and this belongs to a relatively advanced core algorithm for solving the RIS radio frequency matrix of the physical layer security, which takes into account the adjustable iteration number and adjustable processing complexity from the algorithm implementation, and has a significant advantage in processing speed compared with other physical layer security algorithms of RIS. From the algorithm level, the complexity is controllable, the iteration number is controllable, and the running memory is controllable, and the demand for computing power is greatly optimized under the condition of the physical layer security. In summary, the present application can be widely applied in the field of communication. BRIEF DESCRIPTION OF DRAWINGS

[0030] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments and are not meant to limit the present application. Throughout the drawings, the same reference designators are used to denote like elements. In the drawings:

[0031] Figure 1 is a schematic diagram of the RIS principle of the prior art;

[0032] Figure 2 is a schematic diagram of the RIS system modeling of the embodiment of the present application;

[0033] Figure 3 is a flowchart of the implementation of the high-efficiency low-computing-power physical layer security communication method of the present application;

[0034] Figure 4 is a structural diagram of the electronic device of the embodiment of the present application. DETAILED DESCRIPTION

[0035] It should be understood that the terms used herein are for the purpose of describing particular example embodiments and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0036] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to differentiate one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and the like, and other ordinal terms, as used herein, are used to refer to various elements, components, regions, layers or sections, and do not imply a particular order or sequence. Thus, an element, component, region, layer or section discussed below as being first can be discussed as being second, or vice versa, without departing from the teachings of the example embodiments.

[0037] For ease of description, spatial relative terms can be used herein to describe the relationship of one element or feature to another element or feature as shown in the drawings, such as "inner", "outer", "inside", "outside", "lower", "upper", and the like. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0038] One of the main drawbacks of current physical layer security technology is the complexity of multi-user scenarios, and the RIS selection algorithm has an exponential growth in computational complexity when the Internet of Things is accessed on a large scale; there is a lack of effective defense models for eavesdropper collaborative attack scenarios. The present application mainly solves the regulation coefficient of the RIS regulation unit under the system model of the eavesdropper participating in the multi-user scenario, so as to achieve the target parameter adjustment as soon as possible with less calculation cost, and simultaneously consider the comprehensive influence of the user channel and the eavesdropping channel on the RIS phase shift matrix in the RIS. How to accurately and quickly select the appropriate phase shift matrix under two limiting conditions is a technical problem that needs to be solved at present. The high-efficiency low-computing-power physical layer security communication method, device and medium based on intelligent metasurface provided by the present application, comprising: S1, inputting the channel matrix h1, h2 between the base station and the desired user and the eavesdropper; S2, setting the iteration number I, and initializing the iteration number i = 0 and u (0) , wherein u (0) is a one-dimensional vector, and the dimension is consistent with the number of array units of the RIS; S3, randomly generating S candidate RIS phase shift matrices according to u i ; S4, obtaining the equivalent channel matrix according to the channel matrix h1 and the candidate RIS phase shift matrix, and calculating the corresponding precoding matrix W; S5, calculating the maximum achievable secure rate of each candidate RIS phase shift matrix according to the equivalent channel matrix and the channel matrix H2 and the precoding matrix W; S6, arranging the candidate RIS phase shift matrix Θ in descending order according to the maximum achievable secure rate; S7, selecting S' "elite" RIS phase shift matrices Θ with the maximum secure rate; S8, updating u based on the selected S' "elite" RIS phase shift matrices Θ.(i+1) , set i = i + 1, return to step S3 until i = I, end; S9, output quasi-optimal RIS phase shift matrix Θ for realizing high-performance low-computing power physical layer security communication.

[0039] Exemplary embodiments of the present application will be described in greater detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0040] Embodiment one: a RIS-assisted wireless communication system as shown in Figure 2 The transmitting end base station is configured with M transmitting antennas, assuming that the receiving end is a single antenna user, in addition, there are K malicious eavesdroppers aiming to expect to eavesdrop on the information of the receiving end. An RIS is configured between the base station and the single antenna user to assist secure communication, and the number of reflecting elements on the RIS is N. Since the positions of the RIS and the base station are usually fixed, the present application assumes that the beam between the RIS and the base station has been pre-aligned. Through the reflection phase shift of the RIS, the reflected signal power is increased at the expected receiving end, while the signal power at the eavesdropper end is reduced.

[0041] It should be noted that there are currently various methods for channel estimation of RIS-assisted wireless communication. Therefore, the present application can assume that the global channel state information (CSI) of the user of the expected receiving end is completely known for the joint design of beamforming. The eavesdroppers tend to passively hide their existence, and their CSI is usually not available.

[0042] The present application sets the channels between the base station and the expected user, the eavesdropper, and the RIS as and where h 2,k represents the channel between the base station and the kth eavesdropper.

[0043] The channel between the RIS and the expected user is set as The phase shift matrix of the RIS Therefore, the signal received by the expected user can be represented as:

[0044] y1 = (h1 + rΘG)W + n1;

[0045] where n1 is the noise received by the expected user, which is subject to complex Gaussian distribution and can be represented as σ1 noise power, For complex Gaussian distribution, let h = h1 + rΘG, Θ is the phase shift matrix of RIS.

[0046] When the propagation direction of the signal is intelligently regulated by RIS, RIS will not generate a beam aligned with the direction of the eavesdropper. Therefore, the received signal of the eavesdropper can be expressed as:

[0047] y2 = H2s + n2;

[0048] Where H2 represents the channel between the base station and the eavesdropper, s is the base station transmitting signal, n2 is the eavesdropper receiving end noise, which obeys complex Gaussian distribution, and can be expressed as σ2 noise power. Generally, it can be considered that σ = σ1 = σ2.

[0049] The present application adopts the widely used Saleh-Valenzuela multipath channel model to depict the limited scattering characteristics and spatial correlation characteristics of the millimeter wave channel, as shown in the following formula:

[0050]

[0051] Where L k Indicates the number of multipaths for each user, α (l) represents the complex gain of the path, respectively represent the azimuth angle and the elevation angle of the data stream leaving the base station, represents the N × 1 array response vector. Here, the typical antenna array is a uniform planar array (UPA), assuming that there are N1 antenna devices in the horizontal direction and N2 antenna devices in the vertical direction (N = N1 × N2), then the array response vector at this time can be written as:

[0052]

[0053] Where, represents the kronecker product, and the array response vector expressions are respectively λ is the wavelength, d1 represents the distance of the antenna device unit in the horizontal direction, and D2 represents the distance of the antenna device unit in the vertical direction. In the millimeter wave band, it is usually set

[0054] The expected rate of the user and the eavesdropper can be expressed as:

[0055] C1 = log2 |1 + ρhWss H W H h H |;

[0056] C2 = log2 |1 + ρH2WssH W H H2 H |;

[0057] wherein, s represents a transmit signal vector, s H is the conjugate transpose of the transmit signal vector, H2 represents a channel between the base station and the eavesdropper, H2 H represents the conjugate transpose of H2, h = h1 + rΘG, and W is a precoding matrix.

[0058] Therefore, the achievable secure rate can be represented as:

[0059] C(Θ) = C1 - C2.

[0060] In physical layer security, the optimization goal of the embodiment is to maximize the secure rate C(Θ) of the intelligent metasurface assisted communication system, C(Θ) is a cost function, and a suitable Θ is found by taking C(Θ) minimization as the goal, wherein Θ is a phase shift matrix of the RIS, with a dimension of N x N, and other elements except the diagonal line are 0.

[0061] As mentioned earlier, since the mainstream RIS now uses low-energy PIN diodes to achieve low-precision phase shifting. For PIN diodes, their on-off states correspond to phase shifts of 0 and π, respectively. Therefore, the values on the diagonal of Θ are taken from The phase shift matrix optimization problem of the RIS has a non-convex constraint. Due to this non-convex constraint, the optimal solution is a brute-force algorithm. However, due to the large number of units of the RIS, this will result in an unbearable search overhead.

[0062] Therefore, in order to reduce the complexity of solving the RIS phase shift matrix optimization problem, the present application proposes a method for obtaining the RIS phase shift matrix based on an elite solution optimization algorithm, which is an iterative method. The optimal RIS phase shift matrix is obtained by minimizing the cross entropy between the RIS phase shift matrix generated in the previous iteration and the RIS phase shift matrix with excellent sum rate indicators generated this time. The specific process is as follows:

[0063] S1, input the channel matrices h1 and H2 between the base station and the desired user and the eavesdropper;

[0064] S2, set the number of iterations I, the candidate value S, and the number of elite solutions S', and initialize the parameters, including the initial value of the number of iterations i = 0 and u (0) .

[0065] In the embodiment, u (0) = 1 / 2 x 1 N×1 , u (0)is a one-dimensional vector, the dimension is consistent with the number of array units of the RIS, and each element in the vector is a probability value, representing the initial probability of the corresponding array unit generating a 0 phase shift, the initial probability is obtained by generating a random number in a uniform distribution of [0, 1], and i satisfies 0≤i≤I.

[0066] S3, according to u i S randomly generates S candidate RIS phase shift matrices Θ s＝1,…,S .

[0067] In this embodiment, u i each element represents the probability of the corresponding array unit generating a 0 phase shift, and the phase shift of the corresponding array unit is randomly generated, for example, u i The first element u i (1) is 0.3, that is, for the first array unit on the RIS, this embodiment randomly generates a 0 phase shift according to a binomial distribution with a probability of 0.3, if this time is successful, the first array unit on the RIS generates a 0 phase shift, if this time fails, it generates a π phase shift; all elements in u i are traversed one by one, and the phase shift of each array unit is randomly generated as the probability of the binomial distribution; the phase shift of each array unit is placed in the diagonal element of the matrix Θ one by one, and the non-diagonal element is kept as 0, to form a phase shift matrix.

[0068] S4, according to the channel matrix and the candidate RIS phase shift matrix, obtain the equivalent channel matrix, and calculate the corresponding precoding matrix W.

[0069] In this embodiment, the equivalent channel refers to the sum of the channels of all signal paths between the base station and the user, which is defined as h eq = h1+rΘG, that is, the channel h1 between the base station receiver and the RIS, plus the product of the channel r between the RIS and the receiver, the phase shift matrix Θ of the RIS, and the channel G between the base station and the RIS.

[0070] In this embodiment, the precoding is calculated using the equivalent channel, and the precoding matrix W = h eq H (h eq h eq H ) -1 , the purpose of the precoding matrix is to improve the strength of the received signal of the user and reduce the strength of the received signal of the eavesdropper.

[0071] S5, calculate the maximum achievable secure rate of each candidate RIS phase shift matrix Θ s＝1,…,S .

[0072] In this embodiment, the achievable security rate of the desired user and the eavesdropper can be expressed as C(Θ) = C1-C2, C1 = log2|1+ρhWss H W H h H |,C2 = log2|1+ρH2Wss H W H H2 H |.

[0073] S6, alternative RIS phase shift matrix Θ s＝1,…,S In descending order of the maximum achievable security rate.

[0074] S7, select S' "elite" RIS phase shift matrix Θ with the maximum achievable security rate.

[0075] In this embodiment, the S' RIS phase shift matrices Θ with the maximum security rate are selected from high to low s＝1,…,S , and S' can usually be set to half of the alternative value S.

[0076] S8, according to update u (i+1) Set i = i + 1, return to step S3 until i = I is finished;

[0077] In this embodiment, the principle of updating u (i+1) is to minimize the cross entropy between the "elite" RIS phase shift matrix generated by u i in step S7 and the RIS phase shift matrix u (i+1) generated this time. The formula for minimizing the cross entropy is as follows: where q(Θ s ;u (i) ) represents the probability of generating Θ s with each element being 0.

[0078] S9, output the quasi-optimal RIS phase shift matrix Θ.

[0079] In this embodiment, when the iteration is finished, u (i+1) where each element will basically converge to a probability of 0 or 1. If the value of an element is greater than 0.5 and close to 1, i.e., the probability of the phase shift of the RIS array unit corresponding to the order being 0 is close to 1, then the 0 phase shift is placed in the diagonal line of the phase shift matrix Θ corresponding to the order; otherwise, if the value of an element is less than 0.5, then the π phase shift is placed in the diagonal line of the phase shift matrix Θ corresponding to the order. By traversing all elements of u (i+1) , the phase shifts of all array units of the RIS are obtained, and the obtained phase shifts are sequentially placed in the corresponding positions of the phase shift matrix Θ, and the quasi-optimal phase shift matrix Θ can be output.

[0080] In conclusion, the application can be applied to the DSP processing module of all mainstream FPGA platforms at present, the data required for processing is correctly obtained through data grabbing, and the RIS module is applied through algorithm calculation, and the phase adjustment matrix of the RIS is updated.

[0081] Embodiment two: the electronic device corresponding to the high-efficiency low-computing-power physical layer security communication method based on the intelligent metasurface provided in embodiment one, the electronic device can be an electronic device for a client, such as a mobile phone, a notebook computer, a tablet computer, a desktop computer, etc., to execute the method of embodiment one.

[0082] As shown in Figure 4 The electronic device includes a processor, a memory, a communication interface and a bus, the processor, the memory and the communication interface are connected through the bus to complete the communication among each other. The memory stores a computer program that can run on the processor, and the processor runs the computer program to execute the method of embodiment one, the implementation principle and technical effects of which are similar to those of embodiment one, and will not be repeated here. Those skilled in the art can understand that Figure 4 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computing device to which the scheme of the present application is applied. The specific computing device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0083] In a preferred embodiment, the logical instructions in the memory described above can be realized in the form of a software functional unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical scheme of the present application essentially or the part that contributes to the prior art or part of the technical scheme can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), an optical disc and various program code storage media.

[0084] In a preferred embodiment, the processor can be a central processing unit (CPU), a digital signal processor (DSP) and various types of general-purpose processors, which are not limited here.

[0085] Embodiment Three: This embodiment provides a computer readable storage medium storing one or more programs, the one or more programs comprising computer instructions, which when executed by a computer, cause the computer to perform the method provided in Embodiment One.

[0086] In a preferred embodiment, the computer readable storage medium can be a tangible device that maintains and stores the program for being executed by an instruction, for example, can be but not limited to an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination of the above. The computer readable storage medium stores computer program instructions, which cause a computer to perform the method provided in Embodiment One.

[0087] The present application is described with reference to flowcharts and / or block diagrams of methods, apparatus (devices) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, a special purpose computer, an embedded processor or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowcharts and / or block diagrams block or blocks. Figure 1 The flowcharts and / or block diagrams can also be implemented by one or more computer programs or program modules. Figure 1 An apparatus can also be implemented by one or more means for carrying out the functions specified in the flowcharts and / or block diagrams block or blocks.

[0088] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions means which implement the function specified in the flowcharts and / or block diagrams block or blocks. Figure 1 The flowcharts and / or block diagrams can also be implemented by one or more computer programs or program modules. Figure 1 An apparatus can also be implemented by one or more means for carrying out the functions specified in the flowcharts and / or block diagrams block or blocks.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowcharts and / or block diagrams block or blocks. Figure 1 The flowcharts and / or block diagrams can also be implemented by one or more computer programs or program modules. Figure 1 An apparatus can also be implemented by one or more means for carrying out the functions specified in the flowcharts and / or block diagrams block or blocks.

[0090] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In the description of the specification, the description of the terms "one preferred embodiment", "further", "specifically", "in this embodiment", and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the specification. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An intelligent metasurface-based high-efficiency low-computational physical layer security communication method, characterized in comprising: S1, inputting a channel matrix h1, h2 between a base station and a desired user, an eavesdropper; S2, set the iteration number I, and initialize the iteration number i = 0 and wherein, is a one-dimensional vector, the dimension is consistent with the array unit number of the RIS; S3. The method of S2, wherein the RIS phase shift matrix is randomly generated. S3. The method of S2, wherein the RIS phase shift matrix is randomly generated. S4. Obtain the equivalent channel matrix based on the channel matrix h1 and the alternative RIS phase-shifting matrix, and calculate the corresponding precoding matrix ; S5、according to the equivalent channel matrix and the channel matrix H2 and the precoding matrix calculating a maximum achievable safe rate for each alternative RIS phase shifting matrix; S6, arranging the selected RIS phase shift matrices in descending order of maximum achievable security rate; S7, selecting S' "elite" RIS phase shift matrices with the maximum security rate; S8, updating of the S' selected "elite" RIS phase-shifting matrices based on the selection , set i = i + 1, return to step S3 until i = I ends; S9, outputting quasi-optimal RIS phase shift matrices for realizing high-efficiency low-computational physical layer security communication.

2. The intelligent metasurface-based high-efficiency low-complexity physical layer security communication method of claim 1, characterized in that, each element in the vector is a probability value representing the initial probability of the corresponding array element producing a 0 phase shift, the initial probability being obtained by generating a random number in a uniform distribution of [0, 1], wherein, The number of reflection units on the RIS is N.

3. The intelligent metasurface-based high-efficiency low-computational-power physical layer security communication method according to claim 1, characterized in that randomly generating S candidate RIS phase-shifting matrices, comprising: According to According to the probability of 0 phase shift corresponding to each element in the matrix, the phase shift corresponding to the array unit on the RIS is randomly generated, and the phase shift of each array unit is placed in the diagonal elements of the matrix one by one, and the non-diagonal elements are kept as 0, to form a phase shift matrix.

4. The intelligent metasurface-based high-efficiency low-complexity physical layer security communication method of claim 1, wherein the equivalent channel refers to a sum of channels of all signal passing paths of the base station and the user, and is defined as wherein for a channel between the RIS and the receiver, for a channel between the base station and the RIS, for an alternative RIS phase-shifting matrix.

5. The intelligent metasurface-based high-efficiency low-computational-power physical layer security communication method of claim 4, wherein a precoding matrix is used to increase the strength of the received signal of the user and reduce the strength of the received signal of the eavesdropper, the precoding matrix W = [w1, w2, w3, w4]T. , is an equivalent channel, is is a conjugate transpose matrix of 6. The high-efficiency, low-computing-power physical layer secure communication method based on intelligent metasurfaces according to claim 5, characterized in that the maximum achievable secure rate of each candidate RIS phase-shifting matrix is ​​calculated: , In the formula, Represents the transmitted signal vector. It is the conjugate transpose of the transmitted signal vector. This represents the channel between the base station and the eavesdropper. express The conjugate transpose of . This represents noise power.

7. The intelligent metasurface-based high-efficiency low-computational-power physical layer security communication method according to claim 1, characterized in that the updating The specific process is: minimizing the cross entropy between the "elite" RIS phase shift matrix and the RIS phase shift matrix generated this time The specific process is: minimizing the cross entropy between the "elite" RIS phase shift matrix and the RIS phase shift matrix generated this time The cross entropy is obtained between the "elite" RIS phase shift matrix and the RIS phase shift matrix generated this time, and the formula for minimizing the cross entropy is as follows: ； wherein representing generating a probability of being zero for each element, is the i-th RIS phase-shift matrix in the "elite" RIS phase-shift matrix. s RIS phase-shift matrix.

8. An electronic device, comprising: Comprise: At least one processor; And a memory connected in communication with the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor to enable the processor to execute the method according to any one of claims 1-7.

9. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions for: The one or more programs include computer instructions for causing a computer to execute the method according to any one of claims 1-7.

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