Safety rate maximization method of artificial noise assisted covert communication system

Abstract

The invention discloses a safety rate maximization method for an artificial noise assisted covert communication system, and relates to the technical field of communication safety. Comprising the following steps: acquiring channel fading coefficients from a friend source node to a friend destination node, from the friend source node to an eavesdropping node, from the friend source node to an enemy detection node, from the friend destination node to the eavesdropping node, from the friend destination node to the enemy detection node, and a loop self-interference channel fading coefficient of the friend destination node; respectively calculating the transmission rates of the main link and the eavesdropping link according to the channel fading coefficient to obtain the safety rate of the system; performing binary hypothesis testing and concealment measurement analysis on the communication process between the friend nodes to obtain a concealment constraint condition; establishing a system security rate maximization problem of joint optimization of signal sending power and artificial noise power by taking communication concealment between nodes of friends as a constraint; and solving the optimization problem by adopting an iterative algorithm based on successive convex approximation to obtain the maximum safety 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 the fifth generation mobile communication technology (5G), data transmission is more dependent on wireless terminals. However, due to the openness of wireless channels and the broadcast characteristics of electromagnetic transmission, information is vulnerable to theft by illegal nodes, posing a threat to the security of information transmission. Information encryption technology can prevent the content of transmitted information from being deciphered to a certain extent, but even the most advanced encryption algorithms are still at risk of being deciphered by supercomputers and large-scale parallel computing.

[0003] In this regard, physical layer security technology and covert communication technology take advantage of the time-varying and random nature of wireless channels to fundamentally ensure the security of communications. The ultimate goal of physical layer security technology is to ensure that information is not intercepted, so that eavesdroppers cannot learn the content of the information, which can be regarded as concealing the transmission of information itself; covert communication technology refers to the user's desire to send information without being detected by the enemy's detection node, which can be regarded as concealing the entire communication behavior.

[0004] However, most existing studies consider illegal detection or eavesdropping alone to design defense measures, and there is still a lack of research on the scenario of combining physical layer security technology and covert communication technology. Based on the above situation, the present invention proposes a method for maximizing the security rate of an artificial noise-assisted covert communication system, which is of great significance for achieving secure communication. 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 satisfying concealment constraints.

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

[0008] According to the channel fading coefficient, the transmission rates of the main link and the wiretap link are calculated respectively to obtain the security rate of the system.

[0009] Binary hypothesis testing and concealment measurement analysis are performed on the communication process between friendly nodes to obtain concealment constraints.

[0010] Taking the communication concealment between friendly nodes as a constraint, a system security rate maximization problem of jointly optimizing signal transmission power and artificial noise power is constructed.

[0011] An iterative algorithm based on successive convex approximation is used to solve the optimization problem and obtain the maximum safe rate of the system.

[0012] 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 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 includes the friendly destination node operating in full-duplex mode and continuously transmitting artificial noise signals, while the friendly source node intermittently sends communication signals with an unknown regularity, and the received signal of the friendly destination node is expressed as: , 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, 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, It represents the mathematical expectation operation. represents the self-interference elimination 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 .

[0013] 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 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: , 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 The complex Gaussian distribution of .

[0014] 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 wiretap 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 wiretap link can be respectively expressed as: , , in, Indicates the main link transmission rate, Indicates the transmission rate of the wiretap link. The system's security rate is the difference between the transmission rates of the main link and the wiretap link.

[0015] 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 concealment metric analysis, and the concealment constraint condition is obtained, including that under the artificial noise interference of the friendly destination node, the enemy detection node determines whether there is information transmission between the friendly nodes by receiving the communication signal of the friendly source node, and the received signal of the enemy detection node is expressed as: , 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 The complex Gaussian distribution of , This means that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal.

[0016] 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 also makes a binary decision based on the received average power, and the detection performance is expressed as the error detection probability It is expressed as: , Among them, the false alarm probability , probability of missed detection , It means 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; Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, we get The lower bound of is expressed as: , in, is the Kullback-Leibler divergence, and Respectively represent and In the case of the enemy detection node observation value probability distribution, when it satisfies The confidentiality of communication can be guaranteed when , 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: .

[0017] As a preferred solution 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: , Among them, the constraints and Represent the transmission power constraints of the friendly source node and the friendly destination node respectively. Represents the concealed requirements of the communication system by jointly optimizing the signal transmission power and artificial noise power , maximize the safe rate between friendly nodes.

[0018] 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 facing the dual risks of illegal eavesdropping and enemy detection.

[0019] As a preferred solution of the safety rate maximization system of the artificial noise-assisted covert communication system described in the present invention, it includes: a data acquisition module, a safety rate calculation module, a constraint module, a rate maximization module, and an optimization module.

[0020] The data acquisition module is used to obtain the channel fading coefficients between nodes of the artificial noise-assisted covert communication system.

[0021] The safety 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 safety rate of the system.

[0022] 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.

[0023] The rate maximization module is used to construct a system security rate maximization problem that jointly optimizes signal transmission power and artificial noise power, taking the communication concealment between friendly nodes as a constraint.

[0024] 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.

[0025] A computer device comprises 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.

[0026] 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.

[0027] Beneficial effects of the present invention: The method for maximizing the security rate of the artificial noise-assisted covert communication system provided by the present invention takes 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, and further improves the security rate of the artificial noise-assisted covert communication system by jointly optimizing the signal transmission power and the artificial noise power. Compared with the traditional method, the method proposed by the present invention significantly improves the security rate of the covert communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0029] Figure 1 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.

[0030] 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 a second embodiment of the present invention.

[0031] Figure 3 A simulation experiment diagram of a method for maximizing the security rate of an artificial noise-assisted covert communication system provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0033] Example 1, reference 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: 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.

[0034] 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), wherein the friendly destination node is equipped with two antennas to support full-duplex mode, and the other nodes are each equipped with one antenna.

[0035] It should be noted that, assuming that the source node, the destination node, and the idle node have a secret agreement on the time slot index when transmitting private information, the enemy detection node cannot know this agreement, and the idle user can play the role of eavesdropping at a certain moment. Therefore, the eavesdropping node can steal private information at the moment of communication, which is different from the enemy detection node trying to determine whether there is a signal transmission.

[0036] 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 are obtained. The friendly destination node also works in full-duplex mode and continuously transmits artificial noise signals, while the friendly source node intermittently sends communication signals with an unknown rule. The received signal of the friendly destination node is expressed as: , 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, 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, It represents the mathematical expectation operation. represents the self-interference elimination 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 .

[0037] 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 are obtained, and the eavesdropping node is also affected by the artificial noise of the friendly destination node. The received signal is expressed as: , 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 The complex Gaussian distribution of .

[0038] S2: According to the channel fading coefficient, the transmission rates of the main link and the wiretap link are calculated respectively to obtain the security rate of the system.

[0039] Furthermore, according to the channel fading coefficient, the transmission rates of the main link and the wiretap link are calculated respectively, and the security rate of the system including the transmission rates of the main link and the wiretap link can be expressed as: , , in, Indicates the main link transmission rate, Indicates the transmission rate of the wiretap link. The system's security rate is the difference between the transmission rates of the main link and the wiretap link.

[0040] S3: Perform binary hypothesis testing and concealment measurement analysis on the communication process between friendly nodes to obtain concealment constraints.

[0041] Furthermore, binary hypothesis testing and concealment measurement analysis are performed on the communication process between friendly nodes. The concealment constraint conditions include 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: , 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 The complex Gaussian distribution of , This means that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal.

[0042] It should be noted that the communication process between friendly nodes is subjected to binary hypothesis testing and concealment measurement analysis. The concealment 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. It is expressed as: , Among them, the false alarm probability , probability of missed detection , It means 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.

[0043] Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, we get The lower bound of is expressed as: , in, is the Kullback-Leibler divergence, and Respectively represent and In the case of the enemy detection node observation value probability distribution, when it satisfies The confidentiality of communication can be guaranteed when , 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: .

[0044] 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.

[0045] Furthermore, taking the communication concealment between friendly nodes as a constraint, the system security rate maximization problem of jointly optimizing the signal transmission power and the artificial noise power is constructed. This 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, and constructing the system security rate objective function, which is expressed as: , Among them, the constraints and Represent the transmission power constraints of the friendly source node and the friendly destination node respectively. Represents the concealed requirements of the communication system by jointly optimizing the signal transmission power and artificial noise power , maximize the safe rate between friendly nodes.

[0046] 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.

[0047] Furthermore, in the constructed optimization problem, although the signal transmission power of the friendly source node is coupled with the artificial noise power of the friendly destination node, the optimization solutions of these two variables are not correlated, so the optimization problem does not need to use the 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, so the 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: make , , , , , According to the system safety rate objective function, the optimization problem is rewritten as: , in, , , .

[0048] right , Perform a first-order Taylor expansion, expressed as: , in, and They are and A feasible solution of .

[0049] make: , , , , , .

[0050] Therefore, the optimization problem can be transformed into: , 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.

[0051] 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.

[0052] First, the present embodiment of the present invention is implemented 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 the Cartesian coordinate system in meters, with the coordinates of the friendly source node (0,0), the coordinates of the friendly destination node (40,0), the coordinates of the enemy detection node, and the coordinates of the eavesdropping node (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 value of artificial noise power of friendly destination node Set to 10W, the variance of Gaussian white noise .

[0053] Figure 3 It is a relationship diagram 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 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.

[0054] Embodiment 3, an embodiment of the present invention provides a safety rate maximization system for an artificial noise-assisted covert communication system, including a data acquisition module, a safety rate calculation module, a constraint module, a rate maximization module, and an optimization module.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The rate maximization module is used to construct a system security rate maximization problem that jointly optimizes signal transmission power and artificial noise power, taking the communication concealment between friendly nodes as a constraint.

[0059] 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.

[0060] If the function is implemented in the form of 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 part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0061] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0062] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk case (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a 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, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0063] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logical function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0064] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. 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 method for maximizing the security rate of an artificial noise-assisted covert communication system, characterized in that: include: Obtain channel fading coefficients from a friendly source node to a friendly destination node, a friendly source node to an eavesdropping node, a friendly source node to an enemy detection node, a friendly destination node to an eavesdropping node, a friendly destination node to an enemy detection node, and a loop self-interference channel fading coefficient of a friendly destination node; According to the channel fading coefficient, the transmission rates of the main link and the wiretap link are calculated respectively to obtain the security rate of the system; 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 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.

2. The method for maximizing the security rate of an artificial noise-assisted covert communication system according to claim 1, characterized in that: 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 includes the friendly destination node working 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: ， 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, 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, It represents the mathematical expectation operation. represents the self-interference elimination 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 .

3. The method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in claim 2, characterized in that: 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: ， 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 The complex Gaussian distribution of .

4. The method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in claim 3, characterized in that: The transmission rates of the main link and the wiretap 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 wiretap link can be expressed as: ， ， in, Indicates the main link transmission rate, Indicates the transmission rate of the wiretap link. The system's security rate is the difference between the transmission rates of the main link and the wiretap link.

5. The method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in claim 4, characterized in that: The communication process between friendly nodes is subjected to binary hypothesis testing and concealment measurement analysis, and the concealment constraint condition is 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, and the received signal of the enemy detection node is expressed as: ， 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 The complex Gaussian distribution of , This means that the friendly source node does not actually transmit signals. Indicates that the friendly source node actually transmits a signal.

6. The method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in claim 5, characterized in that: The communication process between friendly nodes is subjected to binary hypothesis testing and concealment measurement analysis, and the concealment constraint conditions obtained also include the enemy detection node making a binary decision based on the average power received, and the detection performance is measured by the false detection probability. It is expressed as: ， Among them, the false alarm probability , probability of missed detection , It means 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; Assuming that the enemy detection node adopts optimal detection, according to Pinsker inequality, we get The lower bound of is expressed as: ， in, is the Kullback-Leibler divergence, and Respectively represent and In the case of the enemy detection node observation value probability distribution, when it satisfies The confidentiality of communication can be guaranteed when , 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: 。 7. The method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in claim 6, characterized in that: 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 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 is expressed as: ， Among them, the constraints and Represent the transmission power constraints of the friendly source node and the friendly destination node respectively. Represents the concealed requirements of the communication system by jointly optimizing the signal transmission power and artificial noise power , maximize the safe rate between friendly nodes.

8. A system using the method for maximizing the security rate of an artificial noise-assisted covert communication system as claimed in any one of claims 1 to 7, 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 coefficients between nodes of the artificial noise-assisted covert communication system; The safety 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 safety 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 of jointly optimizing signal transmission power and artificial noise power with 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.

9. 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 method for maximizing the security rate of the artificial noise-assisted covert communication system according to any one of claims 1 to 7 are implemented.

10. 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 method for maximizing the security rate of an artificial noise-assisted covert communication system according to any one of claims 1 to 7 are implemented.

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