A method for maximizing security rate in artificial noise-assisted covert communication system

Abstract

The present invention discloses a method for maximizing the security rate of an artificial noise-assisted covert communication system, which relates to the field of communication security technology. The method comprises obtaining channel fading coefficients from a friendly source node to a friendly destination node, from a friendly source node to an eavesdropping node, from a friendly source node to an enemy detection node, from a friendly destination node to an eavesdropping node, and from a friendly destination node to an enemy detection node, and a loop self-interference channel fading coefficient of the friendly destination node; calculating the transmission rates of a main link and an eavesdropping link respectively according to the channel fading coefficients to obtain the security rate of the system; performing binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraint conditions; constructing a system security rate maximization problem for jointly optimizing signal transmission power and artificial noise power with the communication concealment between friendly nodes as a constraint; and solving the optimization problem using an iterative algorithm based on successive convex approximation to obtain the maximum security rate of the system.

Description

Technical Field

[0001] The present invention relates to the field of communication security technology, and in particular to a method for maximizing the security rate of an artificial noise-assisted covert communication system. Background Art

[0002] With the deployment and commercialization of fifth-generation mobile communication technology (5G), data transmission has become increasingly dependent on wireless terminals. However, due to the open nature of wireless channels and the broadcast nature of electromagnetic transmission, information is vulnerable to eavesdropping by unauthorized nodes, posing a threat to the security of information transmission. While encryption technology can prevent the decryption of transmitted information to a certain extent, even the most advanced encryption algorithms currently face the risk of being cracked by supercomputers and massively parallel computing.

[0003] To address this, physical layer security and covert communication technologies leverage the time-varying and random nature of wireless channels to fundamentally ensure communication security. The ultimate goal of physical layer security is to prevent information from being intercepted, preventing eavesdroppers from learning its content. This can be considered as concealing the transmitted information itself. Covert communication, on the other hand, involves users sending information without being detected by enemy detection nodes, thus concealing the entire communication process.

[0004] However, existing research has mostly focused on designing defenses based solely on illegal detection or eavesdropping, while research on scenarios where physical layer security technologies and covert communication technologies are combined is lacking. Based on this, this paper proposes a method for maximizing the security rate of an artificial noise-assisted covert communication system, which is of great significance for achieving secure communications. Summary of the Invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: how to jointly use artificial noise and covert communication technology to improve system security while meeting the concealment constraint.

[0007] To solve the above technical problems, the present invention provides the following technical solution: a method for maximizing the security rate of an artificial noise-assisted covert communication system, comprising:

[0008] Obtain the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node.

[0009] According to the channel fading coefficient, the transmission rates of the main link and the eavesdropping link are calculated respectively to obtain the security rate of the system.

[0010] Binary hypothesis testing and concealment measurement analysis are performed on the communication process between friendly nodes to obtain concealment constraints.

[0011] Taking the communication concealment between friendly nodes as a constraint, a system security rate maximization problem is constructed by jointly optimizing the signal transmission power and artificial noise power.

[0012] An iterative algorithm based on successive convex approximation is used to solve the optimization problem and obtain the maximum safe rate of the system.

[0013] As a preferred solution of the method for maximizing the security rate of the artificial noise-assisted covert communication system described in the present invention, wherein: the obtaining of the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, and the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node includes the friendly destination node operating in full-duplex mode and continuously transmitting the artificial noise signal, while the friendly source node intermittently sends the communication signal with an unknown regularity, and the received signal of the friendly destination node is expressed as:

[0014] ,

[0015] in, is the signal transmission power of the friendly source node, is the artificial noise power sent by the friendly destination node, represents the channel fading coefficient between the friendly source node and the friendly destination node, SD represents the link from the friendly source node to the friendly destination node, represents the loop self-interference channel fading coefficient of the friendly destination node, DD represents the loop self-interference link of the friendly destination node, is the communication signal sent by the friendly source node in the i-th symbol period, The artificial noise signal sent by the friendly destination node in the i-th symbol period satisfies and , Represents the modulo operation on complex numbers, Indicates the mathematical expectation operation. represents the self-interference cancellation coefficient of the friendly destination node, Represents the Gaussian white noise at the friendly destination node, which has zero mean and variance of The complex Gaussian distribution of .

[0016] As a preferred solution of the method for maximizing the security rate of the artificial noise-assisted covert communication system described in the present invention, wherein: the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, and the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node are obtained, and the eavesdropping node is affected by the artificial noise of the friendly destination node. The received signal is expressed as:

[0017] ,

[0018] in, represents the channel fading coefficient between the friendly source node and the eavesdropping node, SE represents the link from the friendly source node to the eavesdropping node, represents the channel fading coefficient between the friendly destination node and the eavesdropping node, DE represents the link from the friendly destination node to the eavesdropping node, represents the Gaussian white noise at the eavesdropping node, which has zero mean and variance of The complex Gaussian distribution of .

[0019] As a preferred solution of the method for maximizing the security rate of the artificial noise-assisted covert communication system of the present invention, wherein: the transmission rates of the main link and the eavesdropping link are calculated respectively according to the channel fading coefficient, and the security rate of the system including the transmission rates of the main link and the eavesdropping link can be expressed as:

[0020] ,

[0021] ,

[0022] in, Indicates the main link transmission rate, Indicates the transmission rate of the eavesdropping link. The system's security rate is the difference between the transmission rates of the main link and the eavesdropping link.

[0023] As a preferred embodiment of the method for maximizing the security rate of the artificial noise-assisted covert communication system of the present invention, the communication process between friendly nodes is subjected to binary hypothesis testing and covertness metric analysis to obtain covertness constraint conditions, including the following: under artificial noise interference from the friendly destination node, the enemy detection node determines whether information is transmitted between friendly nodes by receiving the communication signal of the friendly source node, and the received signal of the enemy detection node is expressed as:

[0024] ,

[0025] in, represents the channel fading coefficient between the friendly destination node and the enemy detection node, DW represents the link from the friendly destination node to the enemy detection node, represents the channel fading coefficient between the friendly source node and the enemy detection node, SW represents the link from the friendly source node to the enemy detection node, Represents the Gaussian white noise at the enemy detection node, which has zero mean and variance of The complex Gaussian distribution of , Indicates that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal.

[0026] As a preferred solution of the method for maximizing the security rate of the artificial noise-assisted covert communication system of the present invention, wherein: the communication process between friendly nodes is subjected to binary hypothesis testing and covert measurement analysis, and the covert constraint conditions are obtained, and the enemy detection node makes a binary decision based on the average power received, and the detection performance is expressed as the probability of false detection. Expressed as:

[0027] ,

[0028] Among them, the false alarm probability , missed detection probability , Indicates that the enemy detection node believes that the friendly source node has transmitted a signal. Indicates that the enemy detection node believes that the friendly source node has not transmitted a signal. When the communication is determined to be covert communication, To conceal the requirements, The smaller it is, the more concealed the communication will be;

[0029] Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, we can get The lower bound of is expressed as:

[0030] ,

[0031] in, is the Kullback-Leibler divergence, and Respectively represent and The probability distribution of enemy detection node observation value under the condition of When the communication is confidential, , is the signal to interference noise ratio at the enemy detection node, according to the received signal of the enemy detection node The situation is:

[0032] .

[0033] As a preferred embodiment of the method for maximizing the security rate of the artificial noise-assisted covert communication system of the present invention, the system security rate maximization problem of jointly optimizing the signal transmission power and the artificial noise power with the communication concealment between friendly nodes as a constraint includes maximizing the security rate of the system by jointly optimizing the signal transmission power of the friendly source node and the artificial noise power of the friendly destination node, which is expressed as:

[0034] ,

[0035] Among them, the constraints and Represents the transmission power constraints of the friendly source node and the friendly destination node respectively, and the constraint conditions Represents the concealment requirements of the communication system by jointly optimizing the signal transmission power and artificial noise power , maximize the safe rate between friendly nodes.

[0036] Another object of the present invention is to provide a security rate maximization system for an artificial noise-assisted covert communication system, which can reduce the eavesdropping rate at the eavesdropping node and the detection performance at the enemy detection node without increasing the transmission power, and further improve the security rate of the artificial noise-assisted covert communication system through the joint optimization of signal transmission power and artificial noise power, thereby solving the problem of improving the security rate of the communication system under the dual risks of illegal eavesdropping and enemy detection.

[0037] As a preferred solution of the security rate maximization system of the artificial noise-assisted covert communication system described in the present invention, it includes: a data acquisition module, a security rate calculation module, a constraint module, a rate maximization module, and an optimization module.

[0038] The data acquisition module is used to obtain the channel fading coefficients between nodes of the artificial noise-assisted covert communication system.

[0039] The security rate calculation module is used to calculate the transmission rates of the main link and the wiretap link respectively according to the channel fading coefficient to obtain the security rate of the system.

[0040] The constraint module is used to perform binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraint conditions.

[0041] The rate maximization module is used to construct a system security rate maximization problem of jointly optimizing signal transmission power and artificial noise power with the communication concealment between friendly nodes as a constraint.

[0042] The optimization module uses an iterative algorithm based on successive convex approximation to solve the optimization problem and obtain the maximum safe rate of the system.

[0043] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of a method for maximizing the security rate of an artificial noise-assisted covert communication system.

[0044] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for maximizing the security rate of an artificial noise-assisted covert communication system.

[0045] Beneficial Effects of the Invention: The method for maximizing the security rate of an artificial noise-assisted covert communication system provided by the present invention uses the communication concealment between friendly nodes as a constraint and maximizes the security rate of the covert communication system by jointly optimizing the signal transmission power and the artificial noise power. Specifically, the present invention reduces the eavesdropping rate at the eavesdropping node and the detection performance at the enemy detection node without increasing the transmission power. Furthermore, the security rate of the artificial noise-assisted covert communication system is improved by jointly optimizing the signal transmission power and the artificial noise power. Compared with traditional methods, the proposed method significantly improves the security rate of the covert communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 This is an overall flow chart of a method for maximizing the security rate of an artificial noise-assisted covert communication system provided in the first embodiment of the present invention.

[0048] Figure 2 A schematic diagram of a model of a method for maximizing the security rate of an artificial noise-assisted covert communication system provided in accordance with the second embodiment of the present invention.

[0049] Figure 3 This is a simulation experiment diagram of a security rate maximization method for an artificial noise-assisted covert communication system provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0050] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0051] Example 1, with reference to Figure 1 , which is an embodiment of the present invention, provides a method for maximizing the security rate of an artificial noise-assisted covert communication system, comprising:

[0052] S1: Obtain the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node.

[0053] Furthermore, the method of the present invention is applicable to a covert communication system consisting of a friendly source node (S), a friendly destination node (D), an eavesdropping node (E), and an enemy detection node (W). The friendly destination node is equipped with two antennas to support full-duplex mode, and the other nodes are each equipped with one antenna.

[0054] It should be noted that, assuming that the source, destination, and idle nodes have a secret agreement on the time slot index when transmitting private information, the adversary detection node cannot learn this agreement, and the idle user can act as an eavesdropper at a certain moment. Therefore, the eavesdropping node can steal private information at the moment of communication, unlike the adversary detection node that attempts to determine whether a signal is actually being transmitted.

[0055] The channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, and the friendly destination node to the enemy detection node, as well as the loop self-interference channel fading coefficient of the friendly destination node, are obtained. The friendly destination node also operates in full-duplex mode and continuously transmits artificial noise signals, while the friendly source node intermittently sends communication signals with an unknown pattern. The received signal of the friendly destination node is expressed as:

[0056] ,

[0057] in, is the signal transmission power of the friendly source node, is the artificial noise power sent by the friendly destination node, represents the channel fading coefficient between the friendly source node and the friendly destination node, SD represents the link from the friendly source node to the friendly destination node, represents the loop self-interference channel fading coefficient of the friendly destination node, DD represents the loop self-interference link of the friendly destination node, is the communication signal sent by the friendly source node in the i-th symbol period, The artificial noise signal sent by the friendly destination node in the i-th symbol period satisfies and , Represents the modulo operation on complex numbers, Indicates the mathematical expectation operation. represents the self-interference cancellation coefficient of the friendly destination node, Represents the Gaussian white noise at the friendly destination node, which has zero mean and variance of The complex Gaussian distribution of .

[0058] It should also be noted that the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node also include the influence of the eavesdropping node on the artificial noise of the friendly destination node. The received signal is expressed as:

[0059] ,

[0060] in, represents the channel fading coefficient between the friendly source node and the eavesdropping node, SE represents the link from the friendly source node to the eavesdropping node, represents the channel fading coefficient between the friendly destination node and the eavesdropping node, DE represents the link from the friendly destination node to the eavesdropping node, represents the Gaussian white noise at the eavesdropping node, which has zero mean and variance of The complex Gaussian distribution of .

[0061] S2: Calculate the transmission rates of the main link and the eavesdropping link based on the channel fading coefficient to obtain the system's security rate.

[0062] Furthermore, according to the channel fading coefficient, the transmission rates of the main link and the eavesdropping link are calculated respectively, and the security rate of the system including the transmission rates of the main link and the eavesdropping link can be expressed as:

[0063] ,

[0064] ,

[0065] in, Indicates the main link transmission rate, Indicates the transmission rate of the eavesdropping link. The system's security rate is the difference between the transmission rates of the main link and the eavesdropping link.

[0066] S3: Perform binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraints.

[0067] Furthermore, binary hypothesis testing and concealment measurement analysis are performed on the communication process between friendly nodes. The concealment constraint conditions are obtained, including that under the artificial noise interference of the friendly destination node, the enemy detection node determines whether there is information transmission between friendly nodes by receiving the communication signal of the friendly source node. The received signal of the enemy detection node is expressed as:

[0068] ,

[0069] in, represents the channel fading coefficient between the friendly destination node and the enemy detection node, DW represents the link from the friendly destination node to the enemy detection node, represents the channel fading coefficient between the friendly source node and the enemy detection node, SW represents the link from the friendly source node to the enemy detection node, Represents the Gaussian white noise at the enemy detection node, which has zero mean and variance of The complex Gaussian distribution of , Indicates that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal.

[0070] It should be noted that the communication process between friendly nodes is subjected to binary hypothesis testing and stealth measurement analysis. The stealth constraint conditions also include the enemy detection node making a binary decision based on the average power received, and the detection performance is expressed as the false detection probability. Expressed as:

[0071] ,

[0072] Among them, the false alarm probability , missed detection probability , Indicates that the enemy detection node believes that the friendly source node has transmitted a signal. Indicates that the enemy detection node believes that the friendly source node has not transmitted a signal. When the communication is determined to be covert communication, To conceal the requirements, The smaller it is, the more concealed the communication will be.

[0073] Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, we can get The lower bound of is expressed as:

[0074] ,

[0075] in, is the Kullback-Leibler divergence, and Respectively represent and The probability distribution of enemy detection node observation value under the condition of When the communication is confidential, , is the signal to interference noise ratio at the enemy detection node, according to the received signal of the enemy detection node The situation is:

[0076] .

[0077] S4: Taking the communication concealment between friendly nodes as a constraint, a system security rate maximization problem is constructed by jointly optimizing the signal transmission power and artificial noise power.

[0078] Furthermore, with the communication concealment between friendly nodes as a constraint, the system security rate maximization problem of jointly optimizing the signal transmission power and artificial noise power is constructed. This involves maximizing the system security rate by jointly optimizing the signal transmission power of the friendly source node and the artificial noise power of the friendly destination node. The system security rate objective function is constructed and expressed as:

[0079] ,

[0080] Among them, the constraints and Represents the transmission power constraints of the friendly source node and the friendly destination node respectively, and the constraint conditions Represents the concealment requirements of the communication system by jointly optimizing the signal transmission power and artificial noise power , maximize the safe rate between friendly nodes.

[0081] S5: An iterative algorithm based on successive convex approximation is used to solve the optimization problem and obtain the maximum safe rate of the system.

[0082] Furthermore, in the constructed optimization problem, although the signal transmission power of the friendly source node and the artificial noise power of the friendly destination node are coupled, the optimization solutions of these two variables are uncorrelated, so the optimization problem does not require an alternating optimization algorithm. Due to the non-convex objective function and hidden constraints in the above optimization problem, the optimization problem is difficult to solve directly. Therefore, a first-order Taylor expansion is used to transform the original optimization problem into a convex optimization problem, and CVX is used to obtain the optimal solution of the sum. The steps are as follows:

[0083] make , , , , , According to the system safety rate objective function, the optimization problem is rewritten as:

[0084] ,

[0085] in, , , .

[0086] right 、 Perform a first-order Taylor expansion, expressed as:

[0087] ,

[0088] in, and They are and The feasible solution of .

[0089] make: , , , , , .

[0090] Therefore, the optimization problem can be transformed into:

[0091] ,

[0092] The objective function and constraints of the above optimization problem are all convex structures. Therefore, the optimization problem is a standard convex optimization problem and can be solved by the CVX solver.

[0093] Example 2, reference Figure 2-Figure 3 , which is an embodiment of the present invention, provides a method for maximizing the security rate of an artificial noise-assisted covert communication system. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0094] First, the present embodiment of the present invention is realized by using MATLAB tools. Figure 2 As shown in Figure 1, it is assumed that the channels are independent of each other and the channel state information remains constant in the relevant time block. The positions of the friendly source node, friendly destination node, eavesdropping node, and enemy detection node are mapped in a Cartesian coordinate system with units of meters. The coordinates of the friendly source node are (0, 0), the coordinates of the friendly destination node are (40, 0), the coordinates of the enemy detection node are (30, 50), and the coordinates of the eavesdropping node are (30, 50). The path loss fading is modeled as ,in, represents the path loss fading coefficient between nodes, represents the distance between nodes, , represents the reference distance, Set to 1 meter, Represents the path loss index of each link, set , . Self-interference elimination coefficient Set to 0.1 to hide the constraint Set to 0.01, the maximum artificial noise power of the friendly destination node Set to 10W, the variance of Gaussian white noise .

[0095] Figure 3 The figure shows the relationship between the security rate of the covert communication system and the maximum transmission power of the friendly source node in the example of the present invention. It can be seen from the figure that the system security rate of the scheme proposed by the present invention is much higher than the comparison scheme without artificial noise assistance. The security rates obtained by the two schemes increase with the increase of the signal transmission power of the friendly source node, but the greater the signal transmission power, the greater the probability that the enemy detection node successfully detects the information transmission between the friendly nodes, and the more difficult it is to meet the concealment requirement, so the improvement of the security rate of the two schemes is getting smaller and smaller. At the same time, the artificial noise-assisted scheme proposed by the present invention reduces the eavesdropping rate at the eavesdropping node and the detection performance at the enemy detection node without increasing the transmission power, and further improves the security rate of the artificial noise-assisted covert communication system through the joint optimization of power.

[0096] Example 3, an embodiment of the present invention provides a security rate maximization system for an artificial noise-assisted covert communication system, including a data acquisition module, a security rate calculation module, a constraint module, a rate maximization module, and an optimization module.

[0097] Among them, the data acquisition module is used to obtain the channel fading coefficient between each node of the artificial noise-assisted covert communication system.

[0098] The security rate calculation module is used to calculate the transmission rates of the main link and the wiretap link according to the channel fading coefficient to obtain the security rate of the system.

[0099] The constraint module is used to perform binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraint conditions.

[0100] The rate maximization module is used to construct a system security rate maximization problem that jointly optimizes the signal transmission power and artificial noise power, taking the communication concealment between friendly nodes as a constraint.

[0101] The optimization module uses an iterative algorithm based on successive convex approximation to solve the optimization problem and obtain the maximum safe rate of the system.

[0102] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of the present invention. The aforementioned storage medium includes various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0103] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0104] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting, or processing it in another suitable manner as necessary, and then storing it in a computer memory.

[0105] It should be understood that various aspects of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following technologies known in the art may be used: a discrete logic circuit having logic gates for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gates, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc. It should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to be limiting. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and such modifications are intended to be encompassed by the claims of the present invention.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A security rate optimization method for an artificial noise-assisted covert communication system, characterized in that: include: Obtain the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node; According to the channel fading coefficient, the transmission rates of the main link and the eavesdropping link are calculated respectively to obtain the system's security rate; Conduct binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraints; Taking the communication concealment between friendly nodes as a constraint, a system security rate maximization problem of jointly optimizing the signal transmission power and artificial noise power is constructed; An iterative algorithm based on successive convex approximation is used to solve the optimization problem and obtain the maximum safe rate of the system; The acquisition of the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, and the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node includes the friendly destination node operating in full-duplex mode and continuously transmitting an artificial noise signal, while the friendly source node intermittently sends a communication signal with an unknown regularity, and the received signal of the friendly destination node is expressed as: Among them, P S is the signal transmission power of the friendly source node, P D is the artificial noise power sent by the friendly destination node, h SD represents the channel fading coefficient between the friendly source node and the friendly destination node, SD represents the link from the friendly source node to the friendly destination node, and h DD represents the loop self-interference channel fading coefficient of the friendly destination node, DD represents the loop self-interference link of the friendly destination node, and x S (i) is the communication signal sent by the friendly source node in the i-th symbol period, x D (i) is the artificial noise signal sent by the friendly destination node in the i-th symbol period, which satisfies and |·| represents the modulo operation on complex numbers. represents the mathematical expectation operation, φ∈[0,1] represents the self-interference elimination coefficient of the friendly destination node, n D Represents the Gaussian white noise at the friendly destination node, which has zero mean and variance of The complex Gaussian distribution of The transmission rates of the main link and the eavesdropping link are calculated according to the channel fading coefficient, and the security rate of the system including the transmission rates of the main link and the eavesdropping link can be expressed as: Among them, R D Indicates the main link transmission rate, R E Indicates the transmission rate of the eavesdropping link. The system's security rate is the difference between the transmission rates of the main link and the eavesdropping link. The communication process between friendly nodes is subjected to binary hypothesis testing and concealment measurement analysis. The concealment constraint condition obtained includes that under the artificial noise interference of the friendly destination node, the enemy detection node determines whether there is information transmission between friendly nodes by receiving the communication signal of the friendly source node. The received signal of the enemy detection node is expressed as: Among them, h DW represents the channel fading coefficient between the friendly destination node and the enemy detection node, DW represents the link from the friendly destination node to the enemy detection node, and h SW represents the channel fading coefficient between the friendly source node and the enemy detection node, SW represents the link from the friendly source node to the enemy detection node, and n W Represents the Gaussian white noise at the enemy detection node, which has zero mean and variance of The complex Gaussian distribution of Indicates that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal; The communication process between friendly nodes is subjected to binary hypothesis testing and concealment measurement analysis. The concealment constraint condition obtained also includes the enemy detection node making a binary decision based on the average power received. The detection performance is expressed as the false detection probability ξ: Among them, the false alarm probability Probability of missed detection Indicates that the enemy detection node believes that the friendly source node has transmitted a signal. It means that the enemy detection node believes that the friendly source node has not transmitted any signal. When ξ≥1-ε is satisfied, the communication is determined to be covert communication, where ε is the covert requirement. The smaller ε is, the higher the covertness of the communication is. Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, the lower bound of ξ is obtained, which is expressed as: in, is the Kullback-Leibler divergence, and Respectively represent and The probability distribution of enemy detection node observation value under the condition of When the communication is confidential, γ W is the signal to interference noise ratio at the enemy detection node, according to the received signal of the enemy detection node The situation is: The system security rate maximization problem of jointly optimizing the signal transmission power and artificial noise power with the communication concealment between friendly nodes as a constraint includes maximizing the system security rate by jointly optimizing the signal transmission power of the friendly source node and the artificial noise power of the friendly destination node, which can be expressed as: Among them, the constraints and Represents the transmission power constraints of the friendly source node and the friendly destination node respectively, and the constraint conditions Represents the concealment requirement of the communication system, by jointly optimizing the signal transmission power P S and artificial noise power P D , maximize the safe rate between friendly nodes.

2. The method for optimizing the security rate of an artificial noise-assisted covert communication system according to claim 1, wherein: The acquisition of the channel fading coefficients from the friendly source node to the friendly destination node, the friendly source node to the eavesdropping node, the friendly source node to the enemy detection node, the friendly destination node to the eavesdropping node, the friendly destination node to the enemy detection node, and the loop self-interference channel fading coefficient of the friendly destination node also includes the influence of the eavesdropping node on the artificial noise of the friendly destination node, and the received signal is expressed as: Among them, h SE represents the channel fading coefficient between the friendly source node and the eavesdropping node, SE represents the link from the friendly source node to the eavesdropping node, and h DE represents the channel fading coefficient between the friendly destination node and the eavesdropping node, DE represents the link from the friendly destination node to the eavesdropping node, and n E represents the Gaussian white noise at the eavesdropping node, which has zero mean and variance of The complex Gaussian distribution of 3. A system using the security rate optimization method of an artificial noise-assisted covert communication system according to any one of claims 1 and 2, characterized in that: It includes data acquisition module, safety rate calculation module, constraint module, rate maximization module and optimization module; The data acquisition module is used to obtain the channel fading coefficient between each node of the artificial noise assisted covert communication system; The security rate calculation module is used to calculate the transmission rates of the main link and the wiretap link respectively according to the channel fading coefficient to obtain the security rate of the system; The constraint module is used to perform binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraint conditions; The rate maximization module is used to construct a system security rate maximization problem for jointly optimizing signal transmission power and artificial noise power, taking the communication concealment between friendly nodes as a constraint; The optimization module uses an iterative algorithm based on successive convex approximation to solve the optimization problem and obtain the maximum safe rate of the system.

4. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the security rate optimization method of the artificial noise-assisted covert communication system according to any one of claims 1 and 2 are implemented.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the security rate optimization method of the artificial noise-assisted covert communication system according to any one of claims 1 and 2 are implemented.

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