CN114900219A - Intelligent reflecting surface assisted information security transmission method and system - Google Patents
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Abstract
The invention provides an intelligent reflecting surface assisted information safety transmission method and system, comprising an intelligent reflecting surface, a phase shift matrix of an intelligent reflecting element, a reflecting beam and a reflecting beam, wherein the intelligent reflecting surface is used for constructing the reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element; the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information; calculating the lower bound of the confidentiality rate under the non-perfect interception channel state according to the information received by a legal receiving end and an interception user; constructing an optimized objective function of the maximized secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and carrying out information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm; the invention not only considers the influence of the non-perfection of the eavesdropping channel state information acquisition on the information security transmission, but also realizes the purpose of security communication.
Description
Technical Field
The invention belongs to the technical field of communication systems, and particularly relates to an intelligent reflector assisted information security transmission method and system.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
Physical Layer Security (PLS) has become a promising way to achieve Security for wireless communications. Because it does not require encryption keys and security is essentially by transmission design, one key design metric that is widely adopted in physical layer security is the secrecy rate of the system. Since the secrecy rate is measured by the capacity difference between the legal channel and the eavesdropping channel, how to reduce the communication quality of the eavesdropping channel while improving the capacity of the legal channel is the key point of the physical layer security research. Intelligent Reflective Surface (IRS) has become a key candidate in 6G. By densely deploying intelligent reflective surfaces and intelligently coordinating their reflections in a wireless network, the wireless channel between a transmitter and a receiver can be flexibly controlled to achieve a desired signal propagation environment and potentially achieve a tremendous leap in wireless communication network throughput and reliability.
In the existing active intelligent reflection surface auxiliary communication system, an active intelligent reflection surface is introduced into a wireless communication system design to assist original signal transmission, the reflection coefficient of a reflection unit of the active intelligent reflection surface needs to be optimized, and meanwhile, a receiver needs to optimize a received beam forming vector of the active intelligent reflection surface. A higher spectral efficiency than allocating dedicated communication resources for the respective system is achieved. However, this patent does not consider the security problem of information transmission and does not consider the problem of information leakage.
The inventor finds that most of the work in the existing intelligent reflector auxiliary communication scheme mainly focuses on channel estimation or channel overhead reduction in the intelligent reflector auxiliary communication system, and the intelligent reflector auxiliary safety information transmission problem needs to be researched; and the gain of the prior investigated privacy performance mostly depends on perfect eavesdropping of the user channel state information, which is only a very ideal assumption. In an actual communication system, in order to realize effective eavesdropping, an eavesdropping user is not discovered by a legal user, and often keeps silent or hides the existence of the eavesdropping user, and does not actively feed back or feed back accurate eavesdropping channel information to the legal user, so that the legal communication user is difficult to obtain perfect eavesdropping channel state information. Such uncertainty factors can lead to serious information leakage and significant degradation of system security performance.
Disclosure of Invention
Aiming at an information security transmission system with non-perfect and knowable eavesdropping channel state information, a confidentiality rate closed expression and a confidentiality rate lower bound under the non-perfect eavesdropping channel state information are theoretically deduced, the invention provides a robust security transmission method based on intelligent reflecting surface phase shift matrix design, so that the system confidentiality rate is maximized, and the information security transmission is realized.
In order to achieve the above object, in a first aspect, the present invention provides an intelligent reflector assisted information security transmission method, which adopts the following technical scheme:
the intelligent reflecting surfaces are arranged on the surfaces of different buildings, and each intelligent reflecting surface is provided with a plurality of reflecting elements;
the intelligent reflecting surface constructs a reflecting beam by adjusting a phase shift matrix of the reflecting element;
by utilizing the reflected wave beam, the intelligent reflecting surface directly reflects the information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
calculating the lower bound of the confidentiality rate under the non-perfect interception channel state according to the information received by a legal receiving end and an interception user;
and constructing an optimized objective function of the maximized secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and carrying out information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm.
The method for calculating the lower bound of the confidentiality rate under the condition that the intercepted channel state information is not perfect according to the information received by the legal receiving end and the intercepted user specifically comprises the following steps:
determining information received by a legal receiving terminal and information received by an eavesdropping user;
determining the signal-to-noise ratio of the legal receiving terminal and the signal-to-noise ratio of the eavesdropping user based on the information received by the legal receiving terminal and the information received by the eavesdropping user;
and considering the imperfect wiretap channel state information, and calculating the lower bound of the secret rate under the condition that the wiretap channel state information is not perfectly known.
Further, the information received by the legal receiving end and the eavesdropping user are respectively:
wherein the content of the first and second substances,
is the reflection matrix of the kth intelligent reflecting surface,
and
respectively from the source to the k-th intelligent reflector and the k-th intelligent reflector to the legal receiver, wherein the channel is completely known at the source;
is additive white noise (AWGN) at the legitimate receiving end; g IE，m Representing the channel gain of the mth intelligent reflecting surface to the eavesdropping user, wherein the channel gain is known to all legal users;
is additive white noise (AWGN) at the eavesdropping user.
Further, determining the signal-to-noise ratio of the legal receiving end and the signal-to-noise ratio of the eavesdropping user based on the information received by the legal receiving end and the information received by the eavesdropping user specifically comprises:
wherein the content of the first and second substances,
is the reflection matrix of the kth intelligent reflecting surface,
and
respectively from the source to the k-th intelligent reflector and the k-th intelligent reflector to the legal receiver, wherein the channel is completely known at the source;
is additive white noise (AWGN) at the legitimate receiving end; g IE，m Indicating the channel gain of the mth intelligent reflecting surface to the eavesdropping user.
Further, the calculating a lower bound of the secret keeping rate under the imperfect eavesdropping channel state by considering the imperfect eavesdropping channel state information specifically includes:
constructing non-perfect eavesdropper channel state information;
and according to the triangle inequality, the Cauchy inequality and the maximum signal-to-noise ratio of the eavesdropping user, the lower bound of the secrecy rate under the channel state is not intercepted perfectly.
Further, the constructing of the imperfect eavesdropper channel state information specifically includes:
wherein, the first and the second end of the pipe are connected with each other,
is an estimated channel, Δ g, of the communication link between the intelligent reflector and the eavesdropping user IE Is the channel estimation error. It is assumed here that there is only maximum threshold constraint information for channel errors, i.e. the set of all possible uncertain channel errors is expressed by a continuum omega { | | | Δ g IE，m ||≤∈}。
Further, the lower bound of the secret rate under the non-perfect eavesdropping channel state according to the triangle inequality, the cauchy inequality and the maximum signal-to-noise ratio of the eavesdropping user is specifically as follows:
derived from the triangle inequality and the Cauchy inequality for arbitrary vectors
And
the following inequality is always true,
|a H x+b H x|≤|a H x|+|b H x|≤|a H x|+||b H ||·||x||.
therefore, the temperature of the molten metal is controlled,
for an intelligent reflector-user-eavesdropper link, the maximum signal-to-noise ratio at the eavesdropper is:
wherein m represents the mth intelligent reflecting surface;
is the noise power at Eve;
under the condition of partial channel state information of an eavesdropper, the lower bound of the secrecy rate between the information source and the legal receiving end is as follows:
wherein [ z ]] + ＝max{0，z}。
Further, an optimization objective function for maximizing the secrecy rate is constructed according to the intelligent reflecting surface phase shift matrix, and the optimization objective function specifically comprises the following steps:
assuming that the rate at which the eavesdropper receives the mth intelligent reflecting surface is the maximum, the objective function is written as:
wherein, the objective function is to maximize the signal-to-noise ratio of the legal user, and the constraint condition one is the maximum receiving signal-to-noise ratio threshold constraint of the eavesdropping user, that is
Wherein the parameters
The second constraint condition is the phase shift value constraint of the reflecting element of the intelligent reflecting surface,
indicating that the legitimate user uses the snr information obtained from K ≠ m, (K ≠ 1,2, …, K) smart reflective surfaces.
Further, the objective function is equivalent to two subproblems and the optimal solution is calculated in sequence, specifically:
the objective function is equivalent to two independent sub-problems, namely: theta m And Θ k Wherein k is not equal to m; only when the reflection phase shifts theta m When intercepted by an eavesdropper, the theta k K ≠ m can be optimized first;
based on two independent sub-problems, an optimal maximum method is adopted to find a proxy objective function and solve a closed solution
When the iteration operation converges, the optimal value is obtained
In a second aspect, the invention provides an intelligent reflector assisted information security transmission system, which comprises a plurality of intelligent reflector assisted security transmission models and an intelligent reflector transmission module;
the auxiliary safety communication model with the multiple intelligent reflecting surfaces comprises an information source, a legal receiving end, the multiple intelligent reflecting surfaces and an eavesdropping user;
the intelligent reflecting surface constructs a reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element;
the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
the intelligent reflector transmission module is configured to calculate the lower bound of the communication system secret rate under the non-perfect interception channel state according to the information received by a legal receiving end and an interception user; and constructing an optimized objective function of the maximized secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and carrying out information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm.
Compared with the prior art, the invention has the beneficial effects that:
the invention designs the reflection phase shift matrixes of a plurality of intelligent reflection surfaces to establish the optimization problem of the system secrecy rate, and the unit modulus constraint and the coupling variable of the reflection phase shift are difficult to solve. Therefore, the reflection phase shift optimization problem is equivalent to two independent sub-problems, and the solution is carried out by using the Cauchy inequality and the optimization maximum (MM) algorithm until the algorithm converges. By seeking a proxy function to replace the objective function for optimization, the complexity of the method in actual communication is greatly reduced, and the method is easier to implement.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
Fig. 1 is a block diagram of a flow chart of an intelligent reflector-assisted information security transmission method according to a first embodiment of the present invention;
fig. 2 is a schematic diagram of a multiple intelligent reflective surface assisted secure communication model according to a second embodiment of the present invention;
FIG. 3 is a diagram of a simulation result of worst security rate performance of a system with different numbers of reflective elements for an intelligent reflective surface according to an embodiment of the present invention;
FIG. 4 is a simulation effect diagram of the worst security performance of the system under different iteration times of the iterative algorithm according to the first embodiment of the present invention;
fig. 5 is a graph illustrating the effect of the convergence curve of the iterative algorithm according to different numbers of reflecting elements provided in the embodiment of the present invention.
Detailed Description
The invention is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Example one
The embodiment provides an intelligent reflecting surface assisted information security transmission method, which comprises the following steps:
the intelligent reflecting surface constructs a reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element;
the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
calculating the lower bound of the confidentiality rate under the non-perfect interception channel state according to the information received by a legal receiving end and an interception user;
and constructing an optimized objective function for maximizing the secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and performing information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm.
Specifically, as shown in fig. 1, the present embodiment provides an intelligent reflector assisted information security transmission method, which includes the following specific steps:
s1: the information source sends information carrying privacy signals to the intelligent reflecting surface;
s2: the intelligent reflecting surface reflects the information sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
s3: calculating the lower bound of the confidentiality rate under the non-perfect interception channel state according to the information received by a legal receiving end and an interception user;
s4: constructing an optimization problem of maximizing the secrecy rate according to the reflection phase shift matrixes of the intelligent reflection surfaces;
s5: equating the problem of the reflection phase shift matrix into two independent sub-problems, and sequentially calculating the optimal solutions of different sub-problems by adopting a Cauchy inequality and an optimization-Maximization (MM) algorithm;
s6: and the convergence of the iterative algorithm is proved, the optimal solution obtained under the convergence condition is brought into a transmission system, and the information secret transmission is carried out according to the optimal secret rate obtained under the condition.
In the embodiment, the problem of safe transmission of the multi-intelligent-reflector auxiliary communication system is solved. A direct link between an information source Alice and a user Bob is blocked by barriers, an eavesdropper Eve exists, K intelligent reflecting surfaces are introduced to assist in transmission of confidential information in a coordinated mode, and N intelligent reflecting surfaces exist in the K intelligent reflecting surface k A reflective element therein
Without loss of generality, set
The direct link between the source Alice and the user Bob is blocked by some obstacles, the source transmits a confidential signal to the destination receiving end with the aid of the intelligent reflecting surface, and the eavesdropping user attempts to eavesdrop the signal. The present embodiment considers a quasi-static flat fading channel model.
In step S1, Alice sends the confidential signal to the plurality of intelligent reflective surfaces, and in step S2, the confidential signal is reflected to the desired receiver Bob with the aid of the plurality of intelligent reflective surfaces. Then the signal received at Bob can be written as:
wherein the content of the first and second substances,
is the reflection matrix of the kth intelligent reflecting surface,
in addition, the first and second substrates are,
and
respectively representing the channel from the source to the kth intelligent reflecting surface and the channel from the kth intelligent reflecting surface to the legal receiving end.
Is Additive White Gaussian Noise (AWGN) at the legitimate receiver.
In the step S3: the eavesdropping user can only eavesdrop the reflected beam information of one of the intelligent reflecting surfaces due to the directivity problem of the beam, namely, a channel link from the mth intelligent reflecting surface to the eavesdropping user exists. Therefore, the information received by the eavesdropping user is:
wherein, g IE，m Indicating the channel gain of the mth intelligent reflecting surface to the eavesdropping user.
Is Additive White Gaussian Noise (AWGN) of an eavesdropping user.
Then, we can get the receiving signal-to-noise ratio of the legal user end and the eavesdropping user, specifically,
the signal-to-noise ratio brought by the information from the K intelligent reflecting surfaces received by a legal user is
The signal-to-noise ratio brought by the information from the mth intelligent reflecting surface received by the eavesdropping user is,
since potential eavesdroppers often attempt to hide their presence, their interaction with the communication system is infrequent. A more realistic assumption is that a legitimate user can only obtain partial eavesdropper channel state information. The embodiment adopts an uncertainty model to explain the channel state information of an imperfect eavesdropper, namely:
wherein the content of the first and second substances,
is an estimated channel, Δ g, of the communication link between the intelligent reflector and the eavesdropping user IE Is the channel estimation error. It is assumed here that there is only maximum threshold constraint information for channel errors, i.e. the set of all possible uncertain channel errors is expressed by a continuum omega { | | | Δ g IE，m ||≤∈}。
Can be obtained from triangle inequality and Cauchy inequality, and can be used for arbitrary vector
And
the following inequality is always true
|a H x+b H x|≤a H x|+|b H x|≤|a H x|+||b H ||·||x||. (6)
With the above inequality, therefore, the gain of information gained by an eavesdropping user can be expressed as,
for an intelligent reflector-user-eavesdropper link, the maximum signal-to-noise ratio at the eavesdropper is:
under the condition that the channel state information of a part of eavesdroppers can be known, the lower bound of the secrecy rate of the multi-intelligent-reflector-assisted secure communication system is as follows:
wherein [ z ]] + Max {0, z } indicates that the secret ratio is a non-negative value.
In step S4, the reflection matrix of the plurality of intelligent reflection surfaces is optimized with the goal of maximizing the system secret rate performance, that is:
the constraint condition is the phase shift angle constraint of the reflection unit of the intelligent reflection surface. This unity modulus constraint results in zero-forcing (ZF) principles that are difficult to implement on intelligent reflective surfaces, since the constraint results in each element of the reflective matrix being a complex number with a modulus value of one.
To solve the above difficulties, the present invention proposes to provide a threshold constraint for eavesdropping information by a given eavesdropping user, i.e. under the condition of a given eavesdropping information threshold
Maximizing the rate at which legitimate users receive information. Thus, the optimization problem rewrite is expressed as:
wherein, the objective function is to maximize the signal-to-noise ratio of the legal user, and the constraint condition one is the maximum receiving signal-to-noise ratio threshold constraint of the eavesdropping user, that is
Wherein the parameters
And the second constraint condition is the phase shift value constraint of the reflecting element of the intelligent reflecting surface.
Indicating that the legitimate user obtains the snr information from K ≠ m, (K ≠ 1,2, …, K) smart reflective surfaces.
It can be seen visually that g (theta) k ) Reflection matrix theta with mth intelligent reflection surface m Independent of theta only k On the other hand, k ≠ m, and the second component of the objective function is defined by Θ m And (6) determining. Thus, the reflection phase shift optimization problem can be equivalent to two independent sub-problems.
(1)Θ k Optimization of k ≠ m: the reflection phase shift matrix Θ in the above problem k K ≠ m can be optimized by maximizing g (Θ), i.e.:
wherein the vector
Intelligent set of reflector phase shift angles, channel vectors, representing k ≠ m
And indicating a channel set between the intelligent reflecting surface with k ≠ m and a legal receiving end. Channel vector
Indicating the set of channel links between the base station and the intelligent reflecting surface with k ≠ m. In optimizing the reflected phase shift
In the process, the compound is obtained by a Cauchy inequality:
the optimal solution for the reflected phase shift is therefore:
(2)Θ m the optimization of (2): as analyzed above, g (Θ) k ) Is theta m Is constant. Thus, this part of the optimization problem can be written as:
to obtain a closed form solution, we move the information leakage constraint into the objective function. By introducing an extra coefficient in the above problem0 ≦ δ ≦ 1, the inequality constraint becomes a constraint of an equation, that is,
the optimization problem is thus written as:
wherein the matrix parameters
Eavesdropping of channel matrix parameters
They are all hermitian matrices.
Therefore, the objective function is in the form of a generalized eigenvalue problem, but the constraint of a unit modulus makes a traditional generalized eigenvector solver difficult to solve. Therefore, here we use the optimization MM algorithm to find the alternative function of the original objective function, so as to solve the closed form solution.
In particular, a new auxiliary variable y ═ φ is defined H R E φ, the objective function f (φ) is:
it can be shown that f (φ, y) is jointly convex in φ and y. Given a fixed point (phi) 0 ，y 0 ) A linear approximation of the function f (phi, y) can be obtained:
suppose that
Is that
At the point of the nth iteration
Configurable lower bound function
As an alternative to the function of the function,
therefore, the temperature of the molten metal is controlled,
wherein the content of the first and second substances,
is a constant term.
From the above, it can be concluded that, for the (n +1) th iteration, the second and third parts on the right side of the above equation are both constants, so that the optimal phase shift vector solution is composed of the first part
And (6) determining.
The (n +1) th iteration operation optimal solution that can get the above problem is:
wherein
To solve for
Auxiliary parameters in the process.
Thus, in the (n +1) th iteration, the reflected phase shift may be obtained
When the iteration operation converges, the optimal value can be obtained
(3) The convergence of the algorithm is proved by theory, and the method comprises the following specific steps: the MM algorithm ensures that the objective function does not decrease after each iteration. Under the constraint of limited transmission power, the achievable secret ratio has a limited value. Thereby ensuring the convergence of the algorithm. As shown in fig. 3, fig. 4 and fig. 5, a safety performance effect diagram of the multi-intelligent-reflector-assisted secure transmission system proposed in this embodiment is shown.
As can be seen from fig. 3, as the number of the intelligent reflective surfaces increases, the WCSR value increases, and in the three scenarios involved, the WCSR value is greater when N is 64 than when N is 25 and when N is 36. The results of FIG. 3 show that increasing the number of intelligent reflective surfaces can suitably increase the WCSR value; fig. 4 includes three scenarios, each of which considers the number N of different reflections of the intelligent reflective surface, and as can be seen from fig. 4 and 5, the algorithm converges monotonously in all three cases and converges fast. Specifically, for the scenario where N is 25, the WCSR value converges after 13 iterations on average. For N-36, the WCSR value converges on average after 17 iterations, slightly more than N-25 iterations. For N-64, the WCSR value converges after 21 iterations on average, which is more than when N-25 and N-36 are performed. The results of fig. 4 show that an increase in the number of reflective elements does not have much influence on the convergence speed.
Example two
The embodiment provides an intelligent reflector assisted information security transmission system, which comprises a plurality of intelligent reflector assisted security transmission models and an intelligent reflector transmission module, wherein the plurality of intelligent reflector assisted security transmission models comprise an information source, a legal receiving end, a plurality of intelligent reflectors and an eavesdropping user;
the intelligent reflecting surface constructs a reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element;
the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
the secret transmission module is configured to calculate a lower bound of secret rate under the condition that the state information of the eavesdropping channel is not perfectly known according to the information received by a legal receiving end and an eavesdropping user;
the secret transmission module is configured to construct an optimized objective function for maximizing the secret rate according to the intelligent reflecting surface phase shift matrix, the objective function is equivalent to two subproblems, the optimal solution is sequentially calculated, and on the basis of meeting the optimal solution under the convergence condition of the iterative algorithm, information secret transmission is performed according to the optimal secret rate obtained under the optimal solution.
In the system, an information source, a legal receiving end and a wiretap user are provided with only one antenna due to the space limitation of a terminal, and the single antenna transmitting end and the single antenna user are provided;
this embodiment has introduced K intelligent planes of reflection to help secret information's transmission in coordination, has N in the K intelligent plane of reflection k A reflective element therein
Without loss of generality, assume that
The direct link between the source Alice and the user Bob is blocked by some obstacles, the source transmits a confidential signal to the destination receiving end with the aid of the intelligent reflecting surface, and the eavesdropping user attempts to eavesdrop the signal. In addition, in the secure communication, the eavesdropping user usually hides the existence of the eavesdropping user and does not want to or rarely feed back the channel state information of the eavesdropping user to a legal user, so that the non-perfectness of the channel of the eavesdropping user is also a serious threat of information leakage. In the embodiment, the information source communicates with the target receiving end under the assistance of the intelligent reflecting surface, and a potential eavesdropping user attempts to eavesdrop the private information in a communication range.
In this embodiment, confidential information is transmitted with the aid of a plurality of intelligent reflective surfaces. As a novel green passive device, the intelligent reflecting surface also has the advantages of flexible deployment, full duplex service, low energy consumption, low noise, electromagnetic pollution inhibition and the like, and the wireless channel between the transmitter and the receiver can be flexibly controlled by intensively deploying the intelligent reflecting surface in a wireless network and intelligently coordinating the reflection of the intelligent reflecting surface so as to realize an expected signal propagation environment.
The modules are the same as the corresponding steps in the implementation example and application scenarios, but are not limited to the disclosure of the first embodiment. It should be noted that the modules described above as part of a system may be implemented in a computer system such as a set of computer-executable instructions.
In the foregoing embodiments, the descriptions of the embodiments have different emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The proposed system can be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the above-described modules is merely a logical division, and in actual implementation, there may be other divisions, for example, multiple modules may be combined or integrated into another system, or some features may be omitted, or not executed.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, 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 flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may 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 instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may 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 flowchart flow or flows and/or block diagram block or blocks.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (10)
1. An intelligent reflecting surface assisted information security transmission method is characterized by comprising the following steps:
the intelligent reflecting surface constructs a reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element;
the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
calculating the lower bound of the confidentiality rate under the imperfect condition of the state information of the wiretap channel according to the information received by a legal receiving terminal and a wiretap user;
and constructing an optimized objective function of the maximized secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and carrying out information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm.
2. The method as claimed in claim 1, wherein the calculating of the lower bound of the security rate under the imperfect condition of the intercepted channel state information according to the information received by the legal receiving end and the intercepted user comprises:
determining information received by a legal receiving terminal and information received by an eavesdropping user;
determining the signal-to-noise ratio of the legal receiving terminal and the signal-to-noise ratio of the eavesdropping user based on the information received by the legal receiving terminal and the information received by the eavesdropping user;
and considering the imperfect wiretap channel state information, and calculating the lower bound of the secret rate under the condition that the wiretap channel state information is not perfectly known.
3. An intelligent reflector-assisted information security transmission method as claimed in claim 2, wherein the information received by the legal receiving end and the eavesdropping user are respectively:
wherein the content of the first and second substances,
is the reflection matrix of the kth intelligent reflecting surface,
and
respectively from the source to the k-th intelligent reflector and the k-th intelligent reflector to the legal receiver, wherein the channel is completely known at the source;
is additive white noise (AWGN) at the legitimate receiving end; g IE，m Representing the channel gain of the mth intelligent reflecting surface to the eavesdropping user, wherein the channel gain is known to all legal users;
is additive white noise (AWGN) at the eavesdropping user.
4. The method as claimed in claim 2, wherein the step of determining the snr of the legitimate receiver and the snr of the eavesdropping user based on the information received by the legitimate receiver and the information received by the eavesdropping user comprises:
wherein the content of the first and second substances,
is the reflection matrix of the kth intelligent reflecting surface,
and
respectively from the source to the k-th intelligent reflector and the k-th intelligent reflector to the legal receiver, wherein the channel is completely known at the source;
is additive white noise (AWGN) at the legitimate receiving end; g IE，m Indicating the channel gain of the mth intelligent reflecting surface to the eavesdropping user.
5. An intelligent reflector-assisted information security transmission method as claimed in claim 2, wherein the method for calculating the lower bound of the secrecy rate under the imperfect interception channel state by considering the imperfect interception channel state information includes:
constructing non-perfect eavesdropper channel state information;
and according to the triangle inequality, the Cauchy inequality and the maximum signal-to-noise ratio of the eavesdropping user, the lower bound of the secrecy rate under the channel state is not intercepted perfectly.
6. An intelligent reflector-assisted information security transmission method as claimed in claim 5, wherein the constructing of imperfect eavesdropper channel state information includes:
wherein, the first and the second end of the pipe are connected with each other,
is an estimated channel, Δ g, of the communication link between the intelligent reflector and the eavesdropping user IE Is the channel estimation error. It is assumed here that there is only maximum threshold constraint information for channel errors, i.e. the set of all possible uncertain channel errors is expressed by a continuum omega { | | | Δ g IE，m ||≤∈}。
7. The method as claimed in claim 5, wherein the lower bound of the secrecy rate in the imperfect eavesdropping channel state according to the triangle inequality and cauchy inequality and the maximum snr of the eavesdropping user is specifically:
derived from the triangle inequality and the Cauchy inequality for arbitrary vectors
And
the following inequality is always true,
|a H x+b H x|≤|a H x|+|b H x|≤|a H x|+||b H ||·||x||.
therefore, the temperature of the molten metal is controlled,
for an intelligent reflector-user-eavesdropper link, the maximum signal-to-noise ratio at the eavesdropper is:
wherein m represents the mth intelligent reflecting surface;
is the noise power at Eve;
under the condition of partial channel state information of an eavesdropper, the lower bound of the secrecy rate between the information source and the legal receiving end is as follows:
wherein [ z ]] + ＝max{0，z}。
8. The method according to claim 1, wherein an optimized objective function for maximizing the secrecy rate is constructed according to the intelligent reflecting surface phase shift matrix, and specifically comprises:
assuming that the rate at which the eavesdropper receives the mth intelligent reflecting surface is the maximum, the objective function is written as:
wherein, the objective function is to maximize the signal-to-noise ratio of the legal user, and the constraint condition one is the maximum receiving signal-to-noise ratio threshold constraint of the eavesdropping user, that is
Wherein the parameters
The second constraint condition is the phase shift value constraint of the reflecting element of the intelligent reflecting surface,
indicating that the legitimate user obtains the snr information from K ≠ m, (K ≠ 1,2, …, K) smart reflective surfaces.
9. The method for information security transmission assisted by an intelligent reflecting surface as claimed in claim 8, wherein the objective function is equated to two subproblems and the optimal solution is calculated sequentially, specifically:
the objective function is equivalent to two independent sub-problems, namely: theta m And Θ k Wherein k is not equal to m; only when the reflected phase shift Θ m When intercepted by an eavesdropper, [ theta ] k K ≠ m can be optimized first;
based on two independent subproblems, a proxy objective function is searched by adopting an optimization maximum method, and a closed solution is solved
When the iterative operation converges, the optimum is obtained
10. An intelligent reflecting surface assisted information security transmission system is characterized by comprising a plurality of intelligent reflecting surface assisted security transmission models and intelligent reflecting surface transmission modules;
the auxiliary safety communication model with the multiple intelligent reflecting surfaces comprises an information source, a legal receiving end, the multiple intelligent reflecting surfaces and an eavesdropping user;
the intelligent reflecting surface constructs a reflecting beam by adjusting the phase shift matrix of the intelligent reflecting element;
the intelligent reflecting surface directly reflects the received information carrying the privacy signal sent by the information source to a legal receiving end, and the eavesdropping user receives the information;
the intelligent reflector transmission module is configured to calculate the lower bound of the secrecy rate of the communication system under the non-perfect eavesdropping channel state according to the legal receiving end and the eavesdropping user receiving information; and constructing an optimized objective function of the maximized secrecy rate according to the intelligent reflecting surface phase shift matrix, equating the objective function into two subproblems, sequentially calculating an optimal solution, and carrying out information secrecy transmission by using the optimal secrecy rate obtained under the optimal solution on the basis of meeting the optimal solution under the convergence condition of an iterative algorithm.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115412159A (en) * | 2022-09-01 | 2022-11-29 | 大连理工大学 | Safety communication method based on assistance of aerial intelligent reflecting surface |
| CN115426647A (en) * | 2022-08-15 | 2022-12-02 | 中国人民解放军国防科技大学 | Intelligent super-surface-based secure communication method and system |
| CN115484604A (en) * | 2022-08-15 | 2022-12-16 | 华北电力大学（保定） | Cooperative active attack performance evaluation method based on RIS |
| CN115694662A (en) * | 2022-10-21 | 2023-02-03 | 桂林电子科技大学 | Intelligent reflector assisted VLC and RF hybrid network secure transmission method |
| CN117560662A (en) * | 2024-01-10 | 2024-02-13 | 鹏城实验室 | Privacy protection method, device and equipment based on reconfigurable intelligent surface |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111355520A (en) * | 2020-03-10 | 2020-06-30 | 电子科技大学 | Design method of intelligent reflection surface assisted terahertz safety communication system |
| CN111356130A (en) * | 2020-03-05 | 2020-06-30 | 山东师范大学 | Secret transmission method and system for wireless energy supply full-duplex relay cooperation |
| CN112911586A (en) * | 2021-01-18 | 2021-06-04 | 福建农林大学 | Method and system for realizing covert communication based on intelligent reflector |
| CN113938891A (en) * | 2021-10-14 | 2022-01-14 | 北京信息科技大学 | Reflecting surface assisted user node untrusted NOMA network secure communication method |
| CN115278727A (en) * | 2022-06-20 | 2022-11-01 | 重庆邮电大学 | Intelligent reflection surface assisted physical layer security optimization method under inaccurate channel state information condition |
-
2022
- 2022-05-05 CN CN202210479885.2A patent/CN114900219A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111356130A (en) * | 2020-03-05 | 2020-06-30 | 山东师范大学 | Secret transmission method and system for wireless energy supply full-duplex relay cooperation |
| CN111355520A (en) * | 2020-03-10 | 2020-06-30 | 电子科技大学 | Design method of intelligent reflection surface assisted terahertz safety communication system |
| US20210288698A1 (en) * | 2020-03-10 | 2021-09-16 | University Of Electronic Science And Technology Of China | Method for Intelligent Reflecting Surface Aided Terahertz Secure Communication System |
| CN112911586A (en) * | 2021-01-18 | 2021-06-04 | 福建农林大学 | Method and system for realizing covert communication based on intelligent reflector |
| CN113938891A (en) * | 2021-10-14 | 2022-01-14 | 北京信息科技大学 | Reflecting surface assisted user node untrusted NOMA network secure communication method |
| CN115278727A (en) * | 2022-06-20 | 2022-11-01 | 重庆邮电大学 | Intelligent reflection surface assisted physical layer security optimization method under inaccurate channel state information condition |
Non-Patent Citations (3)
| Title |
|---|
| 《中国博士学位论文全文数据库 信息科技辑》: "基于RIS辅助的毫米波系统波束赋形方法及物理层安全研究", 《中国博士学位论文全文数据库 信息科技辑》, 15 January 2022 (2022-01-15), pages 1 - 83 * |
| JINGPING QIAO, MOHAMED-SLIM ALOUINI: "Secure Transmission for Intelligent Reflecting Surface-Assisted mmWave and Terahertz Systems", 《IEEE WIRELESS COMMUNICATIONS LETTERS》, 7 October 2020 (2020-10-07), pages 1743 - 1747 * |
| YANPING WANG等: "Joint Beamforming and Trajectory Design for Aerial Intelligent Reflecting Surface-Aided Secure Transmission", ELECTRONICS, 6 September 2022 (2022-09-06), pages 1 - 18 * |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115426647A (en) * | 2022-08-15 | 2022-12-02 | 中国人民解放军国防科技大学 | Intelligent super-surface-based secure communication method and system |
| CN115484604A (en) * | 2022-08-15 | 2022-12-16 | 华北电力大学（保定） | Cooperative active attack performance evaluation method based on RIS |
| CN115426647B (en) * | 2022-08-15 | 2024-05-24 | 中国人民解放军国防科技大学 | Intelligent super-surface-based secure communication method and system |
| CN115484604B (en) * | 2022-08-15 | 2024-06-07 | 华北电力大学（保定） | RIS-based collaborative initiative attack performance evaluation method |
| CN115412159A (en) * | 2022-09-01 | 2022-11-29 | 大连理工大学 | Safety communication method based on assistance of aerial intelligent reflecting surface |
| CN115412159B (en) * | 2022-09-01 | 2023-10-13 | 大连理工大学 | Safety communication method based on air intelligent reflecting surface assistance |
| CN115694662A (en) * | 2022-10-21 | 2023-02-03 | 桂林电子科技大学 | Intelligent reflector assisted VLC and RF hybrid network secure transmission method |
| CN115694662B (en) * | 2022-10-21 | 2023-09-05 | 桂林电子科技大学 | VLC and RF hybrid network safe transmission method assisted by intelligent reflecting surface |
| CN117560662A (en) * | 2024-01-10 | 2024-02-13 | 鹏城实验室 | Privacy protection method, device and equipment based on reconfigurable intelligent surface |
| CN117560662B (en) * | 2024-01-10 | 2024-05-10 | 鹏城实验室 | Privacy protection method, device and equipment based on reconfigurable intelligent surface |
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