A physical layer information security transmission method based on switching

Abstract

The present invention provides a method for secure transmission of physical layer information based on switching. The method includes: designing an interference signal according to a channel for transmitting a normal signal carrying physical layer information, calculating the signal to noise ratio at the eavesdropper and the legal receiving end based on the normal signal and the interference signal; distributing and deploying multiple jammers in the network, designing a jammer switching strategy according to the signal to noise ratio of the eavesdropper, and the parameters of the jammer switching strategy include a jammer switching threshold value; solving the constraints of the jammer switching strategy by setting an algorithm with the goal of maximizing the switching efficiency of the network, and obtaining the optimal jammer switching threshold value and the confidentiality rate of the normal signal. The method of the present invention discloses a novel physical layer information security transmission strategy based on switching, which combines physical layer security technology with industrial Internet scenarios, and can achieve the goal of protecting private messages in the system from being stolen and countering intelligent mobile eavesdroppers in actual scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of physical layer information transmission, and in particular to a switching-based physical layer information secure transmission method. Background Art

[0002] Industry 4.0 is the fourth industrial revolution or revolutionary production method dominated by intelligent manufacturing. The strategy aims to transform the manufacturing industry into an intelligent one by making full use of information-physical systems. The main implementation method is to use information-physical systems to comprehensively grasp all processes from consumer demand to production and manufacturing, thereby achieving efficient production management. Intelligent manufacturing is a sustainable manufacturing model. With the help of the huge potential of computer modeling and simulation and information and communication technology, it optimizes the design and manufacturing process of products, greatly reduces the consumption of material resources and energy, and the generation of various wastes, while achieving recycling, reducing emissions, and protecting the environment. However, while people enjoy the convenience brought by intelligence, they are also troubled by the leakage of personal data privacy and the theft of privacy information by illegal eavesdroppers. How to ensure that privacy information in the industrial Internet is not stolen has become a new problem that urgently needs to be solved in the current industrial field.

[0003] At present, the security protection technology of wireless communication systems mainly comes from the key encryption technology used in traditional wired communication systems. Key encryption technology is to apply encryption algorithms in the upper layer of the network protocol stack to protect the secure transmission of communication information. It uses specific keys to encrypt information, and the information is transmitted in ciphertext from the sender to the receiver. However, since the security of key encryption technology mainly depends on the computational complexity of the encryption algorithm, its application in wireless communication systems has certain limitations. Physical layer security technology is to achieve information security transmission based on the physical layer by utilizing the time-varying, fading and reciprocal characteristics of wireless channels, such as channel fading, channel noise and phase shift, so as to achieve the purpose of improving the security of wireless communication systems. The theory is that the communication system encrypts based on the characteristics of the physical layer itself, requiring the legitimate receiver to receive information without error while ensuring that other illegal users cannot eavesdrop.

[0004] In general, physical layer security methods are mainly divided into four categories, namely, methods for key distribution management based on physical layer characteristics, methods based on channel security coding, methods based on signal processing, and physical layer authentication technology. Among them, the core idea of ​​the physical layer security method based on signal processing is to improve the channel state of the legitimate channel and deteriorate the channel state of the eavesdropping channel through various signal processing technologies such as precoding technology, beamforming technology, and artificial noise technology, thereby improving the signal-to-noise ratio of the received signal at the legitimate receiving end and reducing the signal-to-noise ratio of the received signal at the illegal eavesdropping end, thereby ensuring the safe transmission of the signal. Compared with the first two methods, this method has a lower complexity and multiple performance index parameters for evaluating the security of the communication system, such as confidentiality capacity and security interruption probability, so it has broad prospects for application in the industrial Internet.

[0005] At present, the shortcomings of the physical layer security strategies in the existing technology include: they are mostly used in networks with multiple antennas and strong transmission power, such as cellular networks, and are not suitable for IoT scenarios with limited capabilities, such as single antennas and weak transmission power.

[0006] Most designs are designed to fight against non-mobile eavesdroppers, but cannot fight against mobile eavesdroppers because mobile eavesdroppers may move to weak interference areas according to the network status.

[0007] The modeling of mobility models is mostly limited to the random mobility model under traditional ideal conditions, which is not suitable for describing the mobility of nodes in actual conditions. Summary of the invention

[0008] The embodiment of the present invention provides a physical layer information security transmission method based on switching, so as to achieve the protection of private information in the system from being stolen.

[0009] In order to achieve the above object, the present invention adopts the following technical scheme.

[0010] A physical layer information security transmission method based on switching, comprising:

[0011] Design interference signals according to the channel for transmitting normal signals carrying physical layer information, and calculate the signal-to-interference-noise ratio at the eavesdropper and the legitimate receiving end based on the normal signal and the interference signal;

[0012] Multiple jammers are distributed and deployed in the network, and a jammer switching strategy is designed according to the signal-to-interference-to-noise ratio of the eavesdropper. The parameters of the jammer switching strategy include a jammer switching threshold value.

[0013] With the goal of maximizing the switching efficiency of the network, an algorithm is set to solve the constraints of the jammer switching strategy to obtain the optimal jammer switching threshold value and the confidentiality rate of the normal signal.

[0014] Preferably, the designing of the interference signal according to the channel transmitting the normal signal, and calculating the signal to interference noise ratio at the eavesdropper and the legitimate receiving end based on the normal signal and the interference signal, comprises:

[0015] The central controller Alice sends a normal signal carrying confidential physical layer information to the legitimate receiving end Bob through a legitimate channel. The jammer Jammer sends a jamming signal to the eavesdropper Eve. The legitimate channel is assumed to be a Gaussian channel, and the received signal y at the legitimate receiving end Bob is obtained. B As shown in formula (1), the received signal y at the eavesdropper Eve is E As shown in formula (2):

[0016]

[0017]

[0018] where d xy represents the distance from node x to node y, a represents the attenuation factor, d BJ Indicates the distance from the jammer to the receiver, d EJ represents the distance from the jammer to the eavesdropper, d AB Indicates the distance from the central controller to the receiver, d AE Indicates the distance from the central controller to the eavesdropper, represents the large-scale fading factor from the jammer to the receiver, represents the large-scale fading factor of the channel from the jammer to the eavesdropper, represents the large-scale fading factor from the central controller to the receiver, represents the large-scale fading factor of the channel from the central controller to the eavesdropper, P x represents the transmission power of node x, h xy Represents the channel between node x and node y, and h is obtained based on the Gaussian channel xy It obeys circular complex normal distribution, n represents the thermal noise of the channel, s is the normal signal sent by Alice carrying confidential physical layer information, and z is the interference signal;

[0019] According to the null space projection method, the interference signal z is designed, and z = Hx, is the Gaussian signal vector, [h BJ ,H] is a set of orthogonal bases, where An orthogonal basis such that h BJ Multiplying the two with H is the zero space, and the signal-to-interference-to-noise ratio γ at Bob is obtained. B As shown in formula (3), the signal-to-interference-noise ratio γ at Eve is E As shown in formula (4):

[0020]

[0021]

[0022] Preferably, the multiple jammers are distributed and deployed in the network, and a jammer switching strategy is designed according to the signal to interference noise ratio of the eavesdropper. The parameters of the jammer switching strategy include a jammer switching threshold value, including:

[0023] Multiple jammers are evenly deployed in the network. The location of each jammer is recorded from a global perspective. The jammer switching strategy is designed based on the signal-to-interference-to-noise ratio of the eavesdropper. The jammer switching strategy includes:

[0024] The eavesdropper Eve selects a position as the initial position, selects a direction between [-π,π], and moves a fixed distance. When the signal-to-noise ratio of his current position is greater than that of his previous position, a direction increment is selected according to the Gaussian distribution and added to his moving direction, so that he can move in the direction where the signal-to-noise ratio becomes better. Conversely, when the signal-to-noise ratio of his current position is less than that of his previous position, a reverse direction increment is selected according to the inverse Gaussian distribution and added to his moving direction.

[0025] When the signal-to-interference-to-noise ratio of the eavesdropper is γ E When it is greater than a jammer switching threshold value β, that is, γ E >β, a switch occurs between jammers in the network. According to the movement of the eavesdropper, the jammer closest to the eavesdropper Eve is selected and activated, and the jammer transmits a jamming signal to the eavesdropper.

[0026] Preferably, the method of solving the constraints of the jammer switching strategy by setting an algorithm with the goal of maximizing the switching efficiency of the network to obtain the optimal jammer switching threshold value and the transmission rate of the normal signal includes:

[0027] The constraints for designing the jammer switching strategy are as follows:

[0028]

[0029] sqF th ≤R S <C B (6)

[0030] β≥β th (7)

[0031] P t (β B )≥δ (8)

[0032] P so (β E ,β)≤∈ (9)

[0033] Where Ψ in formula (5) is the switching efficiency, which is defined as the improvement of the performance of the traditional interference strategy for each switching, R S is the confidentiality rate, which is defined as the difference between the bit rate and the redundancy rate in the normal signal. In formula (6), R th is the lower limit of the confidentiality rate, C B is the channel capacity of the legal channel, β in formula (7) th is the lower limit of the switching threshold, P t is the connection probability of a legal channel, defined as the probability that the signal to noise ratio at Bob is greater than a threshold, δ is the connection constraint, P so is the confidentiality interruption probability of the network, which is defined as the probability that the signal-to-noise ratio at the eavesdropper is greater than a threshold, and ∈ is the confidentiality constraint;

[0034] The above constraints are solved by the greedy algorithm, the maximum value of the network switching efficiency Ψ is searched, and the optimal jammer switching threshold β and the normal signal confidentiality rate R are obtained. S .

[0035] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the method of the present invention discloses a novel switching-based physical layer information security transmission strategy, which combines physical layer security technology with industrial Internet scenarios, and can achieve the goal of protecting privacy messages in the system from being stolen and combating intelligent mobile eavesdroppers in actual scenarios.

[0036] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 A structural diagram of a physical layer security system model provided by an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of an intelligent mobile model of an eavesdropper provided by an embodiment of the present invention;

[0040] Figure 3 A processing flow chart of a method for secure transmission of physical layer information based on switching provided by an embodiment of the present invention;

[0041] Figure 4A schematic diagram of a network switching performance comparison provided by an embodiment of the present invention;

[0042] Figure 5 An environmental schematic diagram of a physical layer system constructed using a software radio platform USRP provided by an embodiment of the present invention;

[0043] Figure 6 A schematic diagram of a constellation diagram of a QPSK signal transmitted by a USRP provided in an embodiment of the present invention;

[0044] Figure 7 A constellation diagram of an eavesdropper receiving end when a traditional interference strategy is adopted provided by an embodiment of the present invention;

[0045] Figure 8 A constellation diagram of a receiving end at an eavesdropper when a switching strategy is adopted is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0047] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or coupling. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0048] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0049] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0050] Physical layer security strategies have practical application value in preventing the theft of secret information in the industrial Internet. Compared with traditional physical layer security strategies based on signal processing, physical layer security strategies based on switching have the following two advantages: 1) they can fight against mobile eavesdroppers in actual situations, and 2) they can fight against intelligent eavesdroppers with the awareness of avoiding interference.

[0051] The embodiment of the present invention provides a switching-based physical layer information security transmission method, which combines physical layer security technology with industrial Internet scenarios, and can achieve the goal of protecting private messages in the system from being stolen and combating intelligent mobile eavesdroppers in actual scenarios.

[0052] A structural diagram of a physical layer security system model provided by an embodiment of the present invention is as follows: Figure 1 Based on Figure 1 The system shown in the embodiment of the present invention establishes a physical layer information security transmission method based on switching according to the actual downlink scenario of the Internet of Things, that is, the central controller wants to send a private command message to the downlink legal receiving end. Figure 1 In the system model shown, the controller of the Industrial Internet, Alice, is deployed at the center of the entire network. It wants to pass a secret message to the legitimate receiver, Bob. At the same time, a mobile eavesdropper, Eve, keeps moving in the network, attempting to steal the secret message. Figure 1 The Jammer in the word refers to a jammer, which is a device used to transmit jamming signals to interfere with eavesdroppers.

[0053] Figure 2 A schematic diagram of an intelligent mobile model of an eavesdropper provided by an embodiment of the present invention. And the present invention reasonably assumes that the central controller maintains a protected area, because there are people in the actual central controller room operating and sending control instructions, and the eavesdropper cannot move to this area in order not to be discovered, such as Figure 2-1 The area within the dotted line. Multiple jammer nodes equipped with multiple antennas are deployed in the network according to the needs. Considering that eavesdroppers will move to areas with poor interference, they will selectively activate a jammer during the communication process, and the jammer will transmit a jamming signal to interfere with the eavesdropper. That is, the present invention designs a switching-based strategy that is different from the traditional cooperative interference strategy of fixing a jammer.

[0054] The embodiment of the present invention provides a processing flow of a method for secure transmission of physical layer information based on switching. Figure 3 As shown, the processing steps include the following:

[0055] Step S10: design an interference signal according to a channel for transmitting a normal signal carrying physical layer information, and calculate the signal to interference noise ratio at the eavesdropper and the legitimate receiving end based on the normal signal and the interference signal.

[0056] Step S20: deploy multiple jammers in a distributed and uniform manner in the network, and design a jammer switching strategy according to the signal to interference and noise ratio of the eavesdropper. The parameters of the jammer switching strategy include a jammer switching threshold.

[0057] Step S30: With the goal of maximizing the switching efficiency of the network, an algorithm is set to solve the objective function of the jammer switching strategy, and the optimal jammer switching threshold value and the confidentiality rate of the normal signal are obtained.

[0058] Specifically, the above step S10 specifically includes: channel estimation and interference signal design. In the communication stage, the central controller Alice sends a normal signal carrying confidential physical layer information to the legitimate receiving end Bob through a legitimate channel. The eavesdropper Eve moves in the network and wants to steal the confidential physical layer information in the above normal signal. The above legitimate channel is assumed to be a Gaussian channel (which can be replaced according to the channel of the actual scenario), and the received signal y at Bob is obtained. B As shown in equation (1), the received signal y at Eve is E As shown in formula (2):

[0059]

[0060]

[0061] where d xy represents the distance from node x to node y, a represents the attenuation factor, d BJ Indicates the distance from the jammer to the receiver, d EJ represents the distance from the jammer to the eavesdropper, d AB Indicates the distance from the central controller to the receiver, d AE Indicates the distance from the central controller to the eavesdropper, represents the large-scale fading factor from the jammer to the receiver, represents the large-scale fading factor of the channel from the jammer to the eavesdropper, represents the large-scale fading factor from the central controller to the receiver, represents the large-scale fading factor of the channel from the central controller to the eavesdropper, P x represents the transmission power of node x, h xy Represents the channel between node x and node y, and h is obtained based on the Gaussian channel xyIt obeys circular complex normal distribution, n represents the thermal noise of the channel, s is the normal signal sent by Alice carrying confidential physical layer information, and z is the interference signal.

[0062] It can be seen from the above formula that the second term of each formula describes the influence of the interference signal on the receiver. In order to eliminate the influence of the interference signal on the legitimate receiver, the present invention designs the interference signal z according to the null space projection method, and designs z to ensure z = Hx, [h BJ ,H] is a set of orthogonal bases, where The orthogonal basis makes the product of the two equal to zero space (which can be understood as 0). The interference signal is random, but the legal channel from the jammer to the receiver is statistically known, that is, h BJ Therefore, the interference signal of this design will cause interference when transmitted along other channels (such as interfering with eavesdroppers along the eavesdropping channel), but it will be eliminated when transmitted to the legitimate receiver due to the design of the orthogonal basis.

[0063] Jammer is used to transmit jamming signals, which can harm eavesdroppers without affecting legitimate communications. BJ ,H] is a set of orthogonal bases, where According to the properties of the orthogonal basis, the interference signal designed by the present invention is z=Hx, where is a Gaussian signal vector. This design can eliminate the influence of interference signals on the legitimate receiving end, so the signal-to-interference-noise ratio at Bob and Eve can be obtained, as shown in equations (3) and (4).

[0064]

[0065]

[0066] Specifically, the above step S20 specifically includes: assuming that the movement of the eavesdropper is a movement with the awareness of avoiding interference, from the perspective of the eavesdropper, according to his goal, he may know the location of the source, but in order not to be discovered, he will not enter the defense area. In addition, he knows nothing about other deployment conditions in the network. If he knows, there is no need to eavesdrop. Therefore, his wisdom is to consider the eavesdropping situation of his own position and get as close as possible to the position in the network that is most suitable for him to eavesdrop, that is, the position where his signal-to-noise ratio is the largest.

[0067] Eve first chooses a position as the initial position, then chooses a direction between [-π,π] and moves a fixed distance. Figure 2There are two situations for the eavesdropper shown. When the signal-to-noise ratio of his current position is greater than that of his previous position, he will then move approximately forward, that is, select a direction increment according to the Gaussian distribution and add it to his moving direction, so that he can move in the direction where the signal-to-noise ratio becomes better; conversely, when the signal-to-noise ratio of his current position is less than that of his previous position, he will then move approximately backward, that is, select a reverse direction increment according to the inverse Gaussian distribution and add it to his moving direction. Finally, through the above model, the eavesdropper can always move in the direction that makes his eavesdropping conditions better, which is due to the characteristics of the Gaussian distribution and his selection strategy.

[0068] The above-mentioned intelligent mobile model of the eavesdropper is a mobile model that can reflect the eavesdropper in the actual industrial Internet. In order to combat such eavesdroppers, the present invention provides a jammer switching strategy. With the help of multiple jammers, according to the signal-to-noise ratio of the eavesdropper, when the signal-to-noise ratio of the eavesdropper is greater than a threshold β, that is, γ E >β, where β is an important threshold of the switching strategy. When a switch occurs between jammers in the network, a jammer closest to the eavesdropper is activated, which transmits a jamming signal. From a global perspective, the position of each jammer is recorded. When the eavesdropper moves, the nearest jammer is selected for jamming according to the eavesdropper's movement.

[0069] Specifically, the above step S30 specifically includes: In order to guide the industrial Internet network designer to optimize the network performance, it is necessary to select the optimal jammer switching strategy jammer switching threshold value β and the normal signal confidentiality rate R S , the constraints (objective function) for designing the above jammer switching strategy are as follows:

[0070]

[0071] sqF th ≤R S <C B (6)

[0072] β≥β th (7)

[0073] P t (β B )≥δ (8)

[0074] P so (β E ,β)≤∈ (9)

[0075] Where Ψ in formula (5) is the switching efficiency, which is defined as the improvement of the performance of the traditional interference strategy for each switching, R S is the confidentiality rate, which is defined as the difference between the bit rate and the redundancy rate in the normal signal. In formula (6), R this the lower limit of the confidentiality rate. The confidentiality rate should be adjusted to meet the minimum network throughput requirement. B is the channel capacity of the legal channel. In order to ensure confidential communication, the confidentiality rate cannot be higher than the channel capacity. In formula (7), β th is the lower limit of the switching threshold. If it is set improperly, the network will face the problem of frequent switching. t is the connection probability of a legal channel, defined as the probability that the signal to noise ratio at Bob is greater than a threshold, δ is the connection constraint, P so is the confidentiality interruption probability of the network, which is defined as the probability that the signal-to-interference-noise ratio at the eavesdropper is greater than a threshold, and ∈ is the confidentiality constraint.

[0076] Under the above constraints, the greedy algorithm can be used to search for the maximum value of the switching efficiency Ψ of the network. The physical meaning of the switching efficiency is the improvement in confidentiality performance brought about by each switch. The confidentiality performance can be measured by the confidentiality interruption probability (the probability that the signal-to-noise ratio at the eavesdropper is greater than the threshold value). The greedy algorithm can be used to search the space of optimization variables in two-dimensional space to obtain the optimal optimization variables to maximize the switching efficiency.

[0077] According to the actual deployment of the industrial Internet, the optimal switching strategy threshold and the optimal confidentiality rate can be obtained, which has certain guiding significance.

[0078] Theoretical simulations using Matlab show that this strategy can effectively combat mobile eavesdroppers in real situations. The network switching performance comparison diagram is shown in the figure. Figure 4 As shown. The upper curve represents the intelligent mobile eavesdropper, and the lower curve represents the random mobile eavesdropper. It can be seen that the present invention can effectively combat the mobile eavesdroppers in the actual industrial Internet. The switching efficiency of the intelligent eavesdropper in the figure is much greater than that of the random eavesdropper. At the same time, the network designer can solve the corresponding optimization problem according to the actual network situation to guide the design of the network.

[0079] Use the software radio platform USRP to build the physical layer system according to the system model diagram. The specific environment is as follows Figure 5 As shown. The digital unit in the figure is meter. In the Ubuntu18.04.5 system, the Gnuradio software platform is used to connect the USRP experimental board with the UHD module for simulation. The functions of software-defined radio can be completed through module connection, such as designing signal power, adjusting transmission coding, adjusting modulation mode, and performing digital signal processing and filtering. In this experiment, Alice is used as the central controller to transmit a secret message. The transmission signal adopts QPSK modulation. The constellation diagram of the USRP transmitting QPSK signal is shown as follows Figure 6 shown.

[0080] The demodulation reception is performed at the Eve receiving end. At the same time, two jammers are deployed in the network to simulate and compare the switching strategy and the traditional strategy. When the traditional jamming strategy is used, the constellation diagram of the eavesdropper receiving end is as follows: Figure 7 As shown in the figure, the constellation diagram of the receiving end at the eavesdropper when the switching strategy is adopted is as follows Figure 8 As shown. It can be seen that when the traditional strategy is adopted, since the smart eavesdropper will avoid interference according to its own state, his received signal can obtain a normal QPSK constellation diagram and decrypt the secret message normally, which shows that the traditional strategy cannot fight against the smart eavesdropper in the actual network. The switching-based physical layer security strategy of the present invention can greatly damage the acceptance ability of the eavesdropper, making his constellation diagram very chaotic and causing the eavesdropper to be unable to decode normally, so as to achieve the purpose of network confidential communication. The practical significance of the present invention is verified.

[0081] In summary, the embodiments of the present invention can effectively combat mobile eavesdroppers in actual situations by deploying switching strategies in actual networks. In the present invention, the interference switching mechanism can be deployed in any industrial Internet as required to flexibly prevent eavesdropping. The optimization strategy designed by the present invention can guide network designers to use switching strategies more reasonably and find the optimal switching threshold and confidentiality rate.

[0082] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0083] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0084] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0085] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for secure transmission of physical layer information based on switching, characterized in that: include: Design interference signals according to the channel for transmitting normal signals carrying physical layer information, and calculate the signal-to-interference-noise ratio at the eavesdropper and the legitimate receiving end based on the normal signal and the interference signal; Multiple jammers are distributed and deployed in the network, and a jammer switching strategy is designed according to the signal-to-interference-to-noise ratio of the eavesdropper. The parameters of the jammer switching strategy include a jammer switching threshold value. With the goal of maximizing the switching efficiency of the network, an algorithm is set to solve the constraints of the jammer switching strategy to obtain the optimal jammer switching threshold value and the confidentiality rate of the normal signal.

2. The method according to claim 1, characterized in that The design of the interference signal according to the channel transmitting the normal signal, and the calculation of the signal to noise ratio at the eavesdropper and the legitimate receiving end based on the normal signal and the interference signal, include: The central controller Alice sends a normal signal carrying confidential physical layer information to the legitimate receiving end Bob through a legitimate channel. The jammer Jammer sends a jamming signal to the eavesdropper Eve. The legitimate channel is assumed to be a Gaussian channel, and the received signal y at the legitimate receiving end Bob is obtained. B As shown in formula (1), the received signal y at the eavesdropper Eve is E As shown in formula (2): where d xy represents the distance from node x to node y, a represents the attenuation factor, d BJ Indicates the distance from the jammer to the receiver, d EJ represents the distance from the jammer to the eavesdropper, d AB Indicates the distance from the central controller to the receiver, d AE Indicates the distance from the central controller to the eavesdropper, represents the large-scale fading factor from the jammer to the receiver, represents the large-scale fading factor of the channel from the jammer to the eavesdropper, represents the large-scale fading factor from the central controller to the receiver, represents the large-scale fading factor of the channel from the central controller to the eavesdropper, P x represents the transmission power of node x, h xy Represents the channel between node x and node y, and h is obtained based on the Gaussian channel xy It obeys circular complex normal distribution, n represents the thermal noise of the channel, s is the normal signal sent by Alice carrying confidential physical layer information, and z is the interference signal; According to the null space projection method, the interference signal z is designed, and z = Hx, is the Gaussian signal vector, [h BJ ,H] is a set of orthogonal bases, where An orthogonal basis such that h BJ Multiplying the two with H is the zero space, and the signal-to-interference-to-noise ratio γ at Bob is obtained. B As shown in formula (3), the signal-to-interference-noise ratio γ at Eve is E As shown in formula (4):

3. The method according to claim 2, characterized in that The multiple jammers are distributed and deployed in the network, and a jammer switching strategy is designed according to the signal-to-interference-to-noise ratio of the eavesdropper. The parameters of the jammer switching strategy include a jammer switching threshold value, including: Multiple jammers are evenly deployed in the network. The location of each jammer is recorded from a global perspective. The jammer switching strategy is designed based on the signal-to-interference-to-noise ratio of the eavesdropper. The jammer switching strategy includes: The eavesdropper Eve selects a position as the initial position, selects a direction between [-π,π], and moves a fixed distance. When the signal-to-noise ratio of his current position is greater than that of his previous position, a direction increment is selected according to the Gaussian distribution and added to his moving direction, so that he can move in the direction where the signal-to-noise ratio becomes better. Conversely, when the signal-to-noise ratio of his current position is less than that of his previous position, a reverse direction increment is selected according to the inverse Gaussian distribution and added to his moving direction. When the signal-to-interference-to-noise ratio of the eavesdropper is γ E When it is greater than a jammer switching threshold value β, that is, γ E >β, a switch occurs between jammers in the network. According to the movement of the eavesdropper, the jammer closest to the eavesdropper Eve is selected and activated, and the jammer transmits a jamming signal to the eavesdropper.

4. The method according to claim 3, characterized in that The method of solving the constraints of the jammer switching strategy by setting an algorithm with the goal of maximizing the switching efficiency of the network to obtain the optimal jammer switching threshold value and the transmission rate of the normal signal includes: The constraints for designing the jammer switching strategy are as follows: s.t.R th ≤R S <C B (6) β≥β th (7) P t (b B )≥δ (8) P so (β E ,β)≤∈ (9) Where Ψ in formula (5) is the switching efficiency, which is defined as the improvement of the performance of the traditional interference strategy for each switching, R S is the confidentiality rate, which is defined as the difference between the bit rate and the redundancy rate in the normal signal. In formula (6), R th is the lower limit of the confidentiality rate, C B is the channel capacity of the legal channel, β in formula (7) th is the lower limit of the switching threshold, P t is the connection probability of a legal channel, defined as the probability that the signal to noise ratio at Bob is greater than a threshold, δ is the connection constraint, P so is the confidentiality interruption probability of the network, which is defined as the probability that the signal-to-noise ratio at the eavesdropper is greater than a threshold, and ∈ is the confidentiality constraint; The above constraints are solved by the greedy algorithm, the maximum value of the network switching efficiency Ψ is searched, and the optimal jammer switching threshold β and the normal signal confidentiality rate R are obtained. S .

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