Concealed optical communication method, system, equipment, product and medium based on reflecting surface

Abstract

The invention relates to the technical field of optical communication, and provides a hidden optical communication method, system, equipment, product and medium based on a reflecting surface, and the method comprises the steps: arranging a transmitting light source at an arrangement position, and arranging receiving equipment and an intelligent reflecting surface; performing primary optical communication and calculating channel gain to obtain optical communication signal representation; constructing a concealment constraint, calculating a key threshold and determining a key threshold limit, and when the key threshold is greater than the key threshold limit, solving a first variance and a first information entropy to obtain a first concealment constraint; when the key threshold is smaller than the key threshold limit, calculating a second information entropy and a second variance to obtain a second concealment constraint; and by taking the first concealment constraint and the second concealment constraint as concealment constraints, constructing a multivariable optimization equation and carrying out segmented solution to obtain optimal communication parameters, and controlling the transmitting light source and the intelligent reflecting surface to carry out optical communication. According to the invention, the communication rate can be improved as much as possible on the premise of ensuring the communication concealment.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technologies, and in particular to a covert optical communication method, system, device, product and medium based on a reflecting surface. Background Art

[0002] As a new type of wireless communication technology, visible light communication realizes data transmission through the visible light band (380 - 780 nm) of light-emitting diodes. Its core advantage lies in the deep integration of lighting and communication functions, without occupying scarce radio frequency spectrum resources, and at the same time having high bandwidth density, strong anti-electromagnetic interference and natural security. With the growing demand for high-speed and secure communication in fields such as smart home, industrial Internet of Things and smart healthcare, visible light communication has become an important supplementary technology for indoor communication in the sixth generation of mobile communication.

[0003] However, the physical characteristics of visible light communication also bring unique security challenges. For example, the light signal forms a wide coverage area in the indoor environment through diffuse reflection, resulting in the possibility that unauthorized users may intercept the signal. In the scenario of multi-access point deployment, signal superposition may lead to power leakage, making it easier for monitors to detect communication behavior. Although traditional physical layer security technologies can prevent the information content from being stolen, they cannot hide the communication behavior itself. Covert communication can control the statistical characteristics of signals, enabling monitors to be unable to distinguish communication signals from background noise, thus avoiding the detection of the existence of communication. Therefore, it has become an important method to enhance the security of visible light communication. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related technologies. For this purpose, the present invention provides a covert optical communication method, system, device, product and medium based on a reflecting surface to achieve relatively covert visible light communication.

[0005] The present invention provides a covert optical communication method based on a reflecting surface, including: S1: Obtain a transmitting light source and determine the installation position, install the transmitting light source at the installation position, and set up a receiving device and a smart reflecting surface; S2: Determine the optical transmission communication conditions, perform primary optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain the optical communication signal representation through the channel gain; S3: Obtain the eavesdropping signal representation according to binary hypothesis testing and the optical communication signal representation, construct a concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint; S4: Obtain the sum of channel gains. Through the sum of channel gains and performing ceiling operation of the maximum upper bound and equation construction, obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; S5: Take the first concealment constraint and the second concealment constraint as the concealment constraint, construct a multi-variable optimization equation through the concealment constraint, perform piecewise solution on the multi-variable optimization equation through the concealment constraint to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0006] According to the reflection-surface-based covert optical communication method provided by the present invention, step S1 specifically includes: S11: Determine the installation position on the ceiling, use a light-emitting diode capable of intensity modulation as the transmitting light source, and install the transmitting light source at the installation position; S12: Use a photodiode as the receiving device, set the receiving device and the intelligent reflecting surface within the communication range, and there is also an eavesdropping device within the communication range.

[0007] According to the reflection-surface-based covert optical communication method provided by the present invention, step S2 specifically includes: S21: Determine the peak power of the transmitting light source and the optical signal vector transmitted, and determine the optical transmission communication conditions according to the peak power and the optical signal vector; S22: Perform primary optical communication according to the optical transmission communication conditions, calculate the channel gains including the direct-link channel gain and the reflection-link channel gain, obtain the additive white Gaussian noise, and obtain the optical communication signal representation through the additive white Gaussian noise and the channel gains.

[0008] According to the reflection-surface-based covert optical communication method provided by the present invention, step S3 specifically includes: S31: Respectively obtain the eavesdropping signal representation under signal transmission and the eavesdropping signal representation under no signal transmission according to binary hypothesis testing and the optical communication signal representation, so as to obtain the probability density function of the eavesdropping signal representation passing the detection; S32: Obtain the relative entropy of the probability density function of the eavesdropping signal representation passing the detection and obtain the concealment threshold, so as to construct the concealment constraint; S33: Calculate the key threshold, calculate the eavesdropping key threshold and the communication key threshold, determine the key threshold bound according to the eavesdropping key threshold and the communication key threshold. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by obtaining the first variance and the first information entropy in the concealment constraint.

[0009] The method for covert optical communication based on a reflecting surface provided by the present invention, step S4 specifically includes: S41: Obtain the sum of channel gains, and through the sum of channel gains and perform a ceiling operation on the maximum upper bound to obtain a ceiling equation; S42: Construct a first covertness parameter equation and a second covertness parameter equation according to the ceiling equation and solve them to obtain a first covertness parameter and a covert probability matrix respectively, and use the first covertness parameter and the covert probability matrix as covert parameters; S43: When the key threshold is less than the key threshold bound, substitute the covert parameters into the ceiling equation, obtain the second information entropy through the ceiling equation, perform probability density function integration according to the first covertness parameter to obtain the second variance, and substitute the second information entropy and the second variance into the covertness constraint to obtain the second covertness constraint.

[0010] In the method for covert optical communication based on a reflecting surface provided by the present invention, in step S5, after constructing the multivariable optimization equation, first fix the peak power, and perform neighborhood selection and reflection spot search according to the peak power to obtain a first optimal communication parameter. Subsequently, fix the first optimal communication parameter and solve for the peak power to obtain an optimal peak power, and use the optimal peak power and the first optimal communication parameter as the optimal communication parameter.

[0011] The present invention also provides a covert optical communication system based on a reflecting surface, including A communication device setting module: used to obtain a transmitting light source and determine a setting position, set the transmitting light source at the setting position, and set a receiving device and an intelligent reflecting surface; An optical communication signal representation module: used to determine optical transmission communication conditions, perform primary optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain an optical communication signal representation through the channel gain; A first covertness constraint module: used to obtain an eavesdropping signal representation according to binary hypothesis testing and the optical communication signal representation, construct a covertness constraint through a covertness threshold and the eavesdropping signal representation, calculate a key threshold and determine a key threshold bound, and when the key threshold is greater than the key threshold bound, obtain a first covertness constraint by obtaining a first variance and a first information entropy in the covertness constraint; A second covertness constraint module: used to obtain the sum of channel gains, and through the sum of channel gains and perform a ceiling operation and equation construction to obtain covertness parameters. When the key threshold is less than the key threshold bound, calculate a second information entropy and a second variance according to the covertness parameters, and substitute the second information entropy and the second variance into the covertness constraint to obtain the second covertness constraint; Parameter optimization module: used to take the first concealment constraint and the second concealment constraint as concealment constraints, construct a multivariable optimization equation through the concealment constraints, solve the multivariable optimization equation piecewise through the concealment constraints, obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflective surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0012] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of any of the above-mentioned covert optical communication methods based on reflective surfaces are implemented.

[0013] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any of the above-mentioned covert optical communication methods based on reflective surfaces are implemented.

[0014] The present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the steps of any of the above-mentioned covert optical communication methods based on reflective surfaces.

[0015] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: The reflective surface-based covert optical communication method, system, device, product and medium provided by the present invention obtain the covert constraints by constructing covert constraints and calculating key thresholds, and obtain the optimal communication parameters by segmented optimization according to the covert constraints, thereby effectively reducing the risk of eavesdropping while ensuring the communication effect and maximizing the communication rate, and improving the covertness and confidentiality of visible light communication.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic flow chart of the reflective surface-based concealed optical communication method provided by the present invention.

[0019] Figure 2 It is a schematic structural diagram of a stealth optical communication system based on a reflecting surface provided by the present invention.

[0020] Figure 3 It is a schematic structural diagram of a stealth optical communication device based on a reflecting surface provided by the present invention.

[0021] Reference numerals: 100, communication device setting module; 200, optical communication signal representation module; 300, first stealth constraint module; 400, second stealth constraint module; 500, parameter optimization module; 810, processor; 820, communication interface; 830, memory; 840, communication bus. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention. The following embodiments are used to illustrate the present invention but cannot be used to limit the scope of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0025] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art can combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0026] The following combines Figures 1 to 3 to describe the specific implementation of the present invention: Figure 1 is a schematic flow chart of the covert optical communication method based on a reflecting surface provided by the present invention. Among them, first, the transmitting light source is set at the set position, and the receiving device and the intelligent reflecting surface are set; then, the initial optical communication is performed according to the optical transmission communication conditions and the channel gain is calculated, so as to obtain the optical communication signal representation; subsequently, the eavesdropping signal representation is obtained, the concealment constraint is constructed, the key threshold limit is determined and the first concealment constraint is obtained; then, the sum of the channel gains is obtained, the concealment parameter is obtained, and the second concealment constraint is obtained according to the concealment parameter; finally, a multi-variable optimization equation is constructed and solved in segments to obtain the optimal communication parameters, so as to perform optical communication.

[0027] The present invention provides a covert optical communication method based on a reflecting surface, including: S1: Obtain the transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface; Furthermore, the purpose of this stage is to set up various devices required for visible light communication, so as to enable visible light communication. Specifically, step S1 specifically includes: S11: Determine the setting position on the ceiling, use a light-emitting diode capable of intensity modulation as the transmitting light source, and set the transmitting light source at the setting position; S12: Use a photodiode as the receiving device, set the receiving device and the intelligent reflecting surface within the communication range, and there is also an eavesdropping device within the communication range.

[0028] For the above steps, the specific implementation in this embodiment is as follows: First, determine the setting positions of the transmitting light sources that are relatively evenly distributed on the ceiling of the room where visible light communication is required, and install multiple light-emitting diodes at the setting positions respectively. Among them, the light-emitting diodes adopt an intensity modulation scheme or a direct detection scheme to perform visible light communication, so intensity modulation can be performed and light signals for communication can be emitted.

[0029] Subsequently, a photodiode is used as the receiving device and the receiving device is set within the communication range of visible light communication, which is a room in this embodiment. The photodiode can receive optical signals. In addition, an intelligent reflecting surface for reflecting optical signals needs to be set within the communication range. The intelligent reflecting surface can reflect the optical signal onto the receiving device after self-reflection, thereby enhancing the channel gain. In addition, the rotation angle of the intelligent reflecting surface can be adjusted, etc., so as to maximize the communication rate while ensuring confidentiality. There are also illegal eavesdropping devices within the communication range, and the eavesdropping devices are also photodiodes. Here, we hope that while the receiving device can smoothly conduct visible light communication and obtain the maximum possible communication rate, the eavesdropping device cannot obtain effective optical signals. In this embodiment, the receiving device is named Bob and the eavesdropping device is named Willie.

[0030] S2: Determine the optical transmission communication conditions, conduct initial optical communication according to the optical transmission communication conditions, and calculate the channel gain. Obtain the optical communication signal representation through the channel gain. Furthermore, the purpose of this stage is to conduct initial optical communication according to the optical transmission communication conditions and calculate the channel gain, so as to obtain the optical communication signal representation. Specifically, step S2 specifically includes: S21: Determine the peak power of the transmitting light source and the optical signal vector transmitted, and determine the optical transmission communication conditions according to the peak power and the optical signal vector. S22: Conduct initial optical communication according to the optical transmission communication conditions, calculate the channel gain including the direct link channel gain and the reflected link channel gain, obtain the additive white Gaussian noise, and obtain the optical communication signal representation through the additive white Gaussian noise and the channel gain.

[0031] For the above steps, the specific implementation in this embodiment is as follows: First, according to experience and the performance of the transmitting light source, determine the peak power A of the transmitting light source during optical communication and the optical signal vector x transmitted by the transmitting light source to the receiving device. Since the optical signal is non-negative, the optical signal vector transmitted by the j-th transmitting light source through the i-th channel should satisfy the following optical transmission communication conditions: where N is the number of channels, is the number of transmitting light sources, Pr[ ] represents the probability of the content in the brackets, is the average optical intensity determined according to the performance of the transmitting light source, represents the expectation of the content in the brackets.

[0032] After that, according to the optical transmission communication conditions, the transmitting light source and the receiving device perform the initial optical communication. The optical communication can be carried out either directly between the transmitting light source and the receiving device or through the reflection of the transmitting light source by the intelligent reflecting surface. Thus, in the link gain, there is the direct link channel gain when the transmitting light source communicates directly with the receiving device and the reflected link channel gain when the transmitting light source communicates through the reflection of the intelligent reflecting surface. First, calculate the direct link gain between the receiving device Bob and the j-th transmitting light source : where m is the Lambert coefficient, is the physical area of the receiving device, is the distance between the receiving device and the j-th transmitting light source, τ is the response speed of the receiving device, is the transimpedance amplifier gain, μ is the refractive index of the optical window of the receiving device, is the transimpedance amplifier gain, is to find the m-th power of cos(), is the irradiation angle when the j-th transmitting light source is connected to the receiving device, that is, the angle between the communication light emitted by the transmitting light source and the normal of the transmitting light source, is the angle between the communication light received by the receiving device and the normal of the receiving device, is the field of view angle of the transmitting light source. Then calculate the reflected link channel gain when the receiving device Bob communicates with the j-th transmitting light source through the k-th intelligent reflecting surface : where ρ is the reflection coefficient of the intelligent reflecting surface, is the distance between the k-th intelligent reflecting surface and the j-th transmitting light source, is the distance between the k-th intelligent reflecting surface and the receiving device, is the irradiation angle when the j-th transmitting light source irradiates the k-th intelligent reflecting surface, is the irradiation angle of the intelligent reflecting surface when the k-th intelligent reflecting surface communicates with the receiving device, is the incident angle when the j-th transmitting light source irradiates the k-th intelligent reflecting surface, is the angle between the communication light and the normal of the receiving device when the k-th intelligent reflecting surface communicates with the receiving device.

[0033] Finally, obtain the additive white Gaussian noise of the receiving device on the i-th channel , and the optical communication signal representation of the i-th channel can be obtained through the additive white Gaussian noise and the channel gain : where, is the number of intelligent reflecting surfaces, is the link state judgment parameter when the j-th transmitting light source communicates with the receiving device through the k-th intelligent reflecting surface. When the state judgment parameter is 1, it indicates that the link exists, and when it is 0, it indicates that the link does not exist.

[0034] S3: Obtain the eavesdropping signal representation according to binary hypothesis testing and optical communication signal representation, construct the concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint; Furthermore, the purpose of this stage is to obtain the eavesdropping signal representation and construct the concealment constraint, so as to construct the key threshold bound and finally obtain the first concealment constraint. Specifically, step S3 specifically includes: S31: Obtain the eavesdropping signal representation under signal transmission and the eavesdropping signal representation under no signal transmission according to binary hypothesis testing and optical communication signal representation respectively, so as to obtain the probability density function of the eavesdropping signal representation passing the detection; S32: Calculate the relative entropy of the probability density function of the eavesdropping signal representation passing the detection and obtain the concealment threshold, so as to construct the concealment constraint; S33: Calculate the key threshold, calculate the eavesdropping key threshold and the communication key threshold, determine the key threshold bound according to the eavesdropping key threshold and the communication key threshold. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint.

[0035] For the above steps, the specific implementation plan in this embodiment is as follows: First, obtain the eavesdropping signal representation under signal transmission and the eavesdropping signal representation under no signal transmission according to binary hypothesis testing and optical communication signal representation respectively. Here, the binary hypothesis testing includes two alternative hypotheses. The first alternative hypothesis indicates that there is no signal transmission between the transmitting light source and the receiving device, and the second alternative hypothesis indicates that there is signal transmission between the transmitting light source and the receiving device. At this time, the eavesdropping signal representation received by the eavesdropping device Willie on the i-th channel is: Among them, is the direct link gain between the eavesdropping device Willie and the j-th transmitting light source, is the reflection link channel gain of the eavesdropping device Willie communicating with the j-th transmitting light source through the k-th intelligent reflecting surface, and its calculation method is the same as that of the link gain of the receiving device. is the link state judgment parameter when the j-th transmitting light source is eavesdropped by the eavesdropping device through the k-th intelligent reflecting surface. is the additive white Gaussian noise of the eavesdropping device on the i-th channel. is the transpose of the link gain matrix composed of the channel gains of the eavesdropping device among all transmitting light sources. is the optical signal matrix composed of the optical signal vectors emitted by all transmitting light sources.

[0036] Then, when the transmitting light source emits an optical signal, calculate the probability density function that the optical signal received by the eavesdropping device is greater than the channel detection value Q set according to experience for Q times, that is, the probability density function that the eavesdropping signal indicates passing the detection at this time. . It is also necessary to calculate the probability density function that the optical signal received by the eavesdropping device is greater than the channel detection value Q set according to experience for Q times when the transmitting light source does not emit an optical signal, that is, the probability density function that the eavesdropping signal indicates passing the detection at this time. , so as to obtain the probability density function that the eavesdropping signal indicates passing the detection. Then, the relative entropy of the probability density function that the eavesdropping signal indicates passing the detection can be obtained, and the concealment threshold can be obtained. , thus constructing the concealment constraint: Among them, represents the relative entropy between the contents in the brackets.

[0037] Subsequently, calculate the key threshold. Further, the upper bound of the relative entropy of the probability density function is deduced as: Among them, represents the information entropy of the contents in the brackets. is the noise variance of the eavesdropping device. In this way, redefine the concealment constraint as: Then, since the system capacity is affected by the key threshold , and the calculated key threshold is: Therefore, define the device key threshold of the u-th device: Among them, u can be B representing the receiving device or W representing the eavesdropping device according to the identity of the device. are all channel gains of the u-th device under the j-th transmitting light source. In this way, the communication key threshold and the eavesdropping key threshold can be calculated according to the identity of the device. When the key threshold is greater than the key threshold limit, that is , where, when max{} represents finding the maximum value within the brackets, since obeys a uniform distribution, thus in the concealment constraint, the first variance E and the first information entropy H can be directly obtained: where represents obtaining the infinity norm. Substituting it into the concealment constraint, the first concealment constraint can be obtained: S4: Obtain the sum of channel gains. Through the sum of channel gains and performing the ceiling operation of the maximum upper bound and equation construction, obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; Furthermore, the purpose of this stage is to obtain the concealment parameter, so as to calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint, then the second concealment constraint can be obtained. Specifically, step S4 specifically includes: S41: Obtain the sum of channel gains. Through the sum of channel gains and performing the ceiling operation of the maximum upper bound, obtain the ceiling equation; S42: Construct the first concealment parameter equation and the second concealment parameter equation according to the ceiling equation and solve them to obtain the first concealment parameter and the concealment probability matrix respectively, and use the first concealment parameter and the concealment probability matrix as the concealment parameters; S43: When the key threshold is less than the key threshold bound, substitute the concealment parameter into the ceiling equation, obtain the second information entropy through the ceiling equation, perform probability density function integration according to the first concealment parameter to obtain the second variance, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint.

[0038] For the above steps, the specific implementation method in this embodiment is as follows: First, calculate the sum of the channel gains of the j-th transmitting light source to the eavesdropping device : where are all the channel gains of the eavesdropping device under the j-th transmitting light source. Subsequently, calculate the sum of the channel gains of all transmitting light sources and perform the ceiling operation of the maximum upper bound through the sum of channel gains to obtain the ceiling equation: where is the capacity factor of the eavesdropping device, is the first concealment parameter, is the input parameter determined according to experience, is the link gain matrix composed of the channel gains of the eavesdropping devices among all the transmitting light sources, is the concealment probability matrix of the eavesdropping devices, is the ceiling operation of taking the maximum upper bound under the constraint of the input parameter. It can be seen that both the concealment probability matrix and the first concealment parameter are unknown values. Therefore, it is necessary to construct and solve the first concealment parameter equation and the second concealment parameter equation.

[0039] First, construct the first concealment equation: The first concealment parameter is the unique positive solution of this equation. Subsequently, construct the second concealment parameter equation: where, is the probability parameter of the j-th transmitting light source, is the probability factor. By calculating the probability parameters of all the transmitting light sources and forming them into a matrix, the concealment probability matrix can be obtained. However, it can be seen that the probability factor is still unknown. Therefore, it is necessary to construct a probability factor equation for solution: where, is the unique positive solution of this equation. In this way, the concealment parameters including the first concealment parameter and the concealment probability matrix are obtained.

[0040] In this way, when the key threshold is less than the key threshold bound, substituting the concealment parameters into the ceiling equation, the capacity factor of the eavesdropping device can be obtained. Since at this time obeys the truncated exponential distribution, the second information entropy is: where, is the sum of the channel gains when j takes .

[0041] Subsequently, in order to solve the second variance , perform probability density function integration according to the probability density function of the truncated exponential distribution and the first concealment parameter: where, is the sum of the channel gains when j takes j - 1.

[0042] After integration, the second variance is finally obtained: Finally, substituting the second information entropy and the second variance into the concealment constraint, the second concealment constraint can be obtained : Among them, is the first auxiliary parameter, is the second auxiliary parameter, is the third auxiliary parameter. The auxiliary parameters are for the convenience of expressing the equation, and: , , S5: Take the first concealment constraint and the second concealment constraint as the concealment constraint, construct a multi-variable optimization equation through the concealment constraint, perform piecewise solution on the multi-variable optimization equation through the concealment constraint to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0043] Furthermore, the purpose of this stage is to construct a multi-variable optimization equation and perform piecewise solution to obtain the optimal communication parameters, so as to control the transmitting light source and the intelligent reflecting surface. Specifically, in step S5, after constructing the multi-variable optimization equation, first fix the peak power, and perform proximity selection and reflection spot search according to the peak power to obtain the first optimal communication parameter. Subsequently, fix the first optimal communication parameter and solve for the peak power to obtain the optimal peak power. Take the optimal peak power and the first optimal communication parameter as the optimal communication parameters.

[0044] For the above steps, the specific implementation method in this embodiment is as follows: First, take the first concealment constraint and the second concealment constraint as the concealment constraint, and construct a multi-variable optimization equation through the concealment constraint: Among them, s.t. represents the constraint condition, means to maximize the lower bound of the capacity of the receiving device, represents the roll angle of the k-th intelligent reflecting surface, represents the pitch angle of the k-th intelligent reflecting surface, represents the link state judgment parameter when the j-th transmitting light source communicates with the u-th device through the k-th intelligent reflecting surface. Here, u can be B or W, representing the receiving device and the eavesdropping device respectively, represents the concealment constraint. As can be seen from the above, the value of b can be 1 or 2, represents the association matrix, including all link state judgment parameters of the receiving device.

[0045] Subsequently, perform piecewise solution, that is, first fix the peak power for optimization: Among them, It means that the peak power is first taken as a fixed value, and adjacent selection and reflection spot search are performed, and is optimized to obtain the optimized as the first optimal communication parameter.

[0046] Subsequently, the first optimal communication parameter is fixed, and the peak power is solved to obtain the optimal communication power: Among them, It means that the first optimal communication parameter after optimization is taken as a fixed value, and the peak power is optimized to obtain the optimal peak power. Here, it can be obtained that when b takes 1, the optimal peak power at this time has a value range of: When b takes 2, the optimal peak power at this time has a value range of: Among them, represents the fourth auxiliary parameter, represents the fifth auxiliary parameter, represents the sixth auxiliary parameter, and: The optimal peak power and the first optimal communication parameter are used as the optimal communication parameters, and the transmitting light source and the intelligent reflecting surface are controlled according to the optimal communication parameters, so as to perform optical communication with the receiving device. In this way, the communication rate can be increased as much as possible on the premise of ensuring communication concealment, that is, it is ensured that the eavesdropping device cannot obtain the communication content, but the communication rate is as high as possible.

[0047] Next, the covert optical communication device based on a reflecting surface provided by the present invention will be described. The covert optical communication device based on a reflecting surface described below can be correspondingly referred to the covert optical communication method described above.

[0048] Figure 2 Illustrates a schematic structural diagram of a covert optical communication system based on a reflecting surface, as Figure 2 shown, for performing the covert optical communication method based on a reflecting surface as described above, including: Communication device setting module 100: used to obtain a transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface; Optical communication signal representation module 200: It is used to determine the optical transmission communication conditions, perform initial optical communication according to the optical transmission communication conditions, calculate the channel gain, and obtain the optical communication signal representation through the channel gain; First concealment constraint module 300: It is used to obtain the eavesdropping signal representation according to the binary hypothesis test and the optical communication signal representation, construct the concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, the first concealment constraint is obtained by obtaining the first variance and the first information entropy in the concealment constraint; Second concealment constraint module 400: It is used to obtain the channel gain sum, perform the ceiling operation of the maximum upper bound and equation construction through the channel gain sum, obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; Parameter optimization module 500: It is used to use the first concealment constraint and the second concealment constraint as the concealment constraint, construct a multi-variable optimization equation through the concealment constraint, solve the multi-variable optimization equation in segments through the concealment constraint to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0049] On the other hand, Figure 3 An example of the physical structure diagram of an electronic device is shown as Figure 3 shown. The electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840. Among them, the processor 810, the communication interface 820, and the memory 830 complete mutual communication through the communication bus 840. The processor 810 can call the logical instructions in the memory 830 to execute the concealment optical communication method based on the reflecting surface. The method includes: S1: Obtain the transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface; S2: Determine the optical transmission communication conditions, perform initial optical communication according to the optical transmission communication conditions, calculate the channel gain, and obtain the optical communication signal representation through the channel gain; S3: Obtain the eavesdropping signal representation according to the binary hypothesis test and the optical communication signal representation, construct the concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, the first concealment constraint is obtained by obtaining the first variance and the first information entropy in the concealment constraint; S4: Obtain the sum of channel gains. Through the sum of channel gains and perform ceiling operation of the maximum upper bound and equation construction to obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; S5: Take the first concealment constraint and the second concealment constraint as the concealment constraint, construct a multi-variable optimization equation through the concealment constraint, solve the multi-variable optimization equation in segments through the concealment constraint to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0050] In addition, when the logical instructions in the above-mentioned memory 830 are implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0051] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the method for reflective-surface-based covert optical communication provided by the above-mentioned various methods. The method includes: S1: Obtain the transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface; S2: Determine the optical transmission communication conditions, perform primary optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain the optical communication signal representation through the channel gain; S3: Obtain the eavesdropping signal representation according to the binary hypothesis test and the optical communication signal representation, construct a concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by obtaining the first variance and the first information entropy in the concealment constraint; S4: Obtain the sum of channel gains. Through the sum of channel gains and perform ceiling operation of the maximum upper bound and equation construction to obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; S5: Take the first concealment constraint and the second concealment constraint as the concealment constraints, construct a multi-variable optimization equation through the concealment constraints, perform piecewise solution on the multi-variable optimization equation through the concealment constraints to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0052] On the other hand, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is used to execute the method for covert optical communication based on a reflecting surface provided by the above methods. The method includes: S1: Obtain the transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface; S2: Determine the optical transmission communication conditions, perform initial optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain the optical communication signal representation through the channel gain; S3: Obtain the eavesdropping signal representation according to the binary hypothesis test and the optical communication signal representation, construct the concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by obtaining the first variance and the first information entropy in the concealment constraint; S4: Obtain the sum of channel gains. Through the sum of channel gains and perform ceiling operation of the maximum upper bound and equation construction to obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; S5: Take the first concealment constraint and the second concealment constraint as the concealment constraints, construct a multi-variable optimization equation through the concealment constraints, perform piecewise solution on the multi-variable optimization equation through the concealment constraints to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to perform optical communication with the receiving device.

[0053] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0054] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the above technical solution, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0055] Finally, 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 them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A method for covert optical communication based on a reflecting surface, characterized in that, Including: S1: Obtain a transmitting light source and determine the installation position, install the transmitting light source at the installation position, and set up a receiving device and an intelligent reflecting surface; S2: Determine the optical transmission communication conditions, conduct initial optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain the optical communication signal representation through the channel gain; S3: Obtain the eavesdropping signal representation based on binary hypothesis testing and the optical communication signal representation, construct a concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint; S4: Calculate the sum of the channel gains. Through the sum of the channel gains and performing a ceiling operation and equation construction, obtain the concealment parameter. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameter, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint; S5: Take the first concealment constraint and the second concealment constraint as the concealment constraint, construct a multi-variable optimization equation through the concealment constraint, solve the multi-variable optimization equation in segments through the concealment constraint to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters, so as to conduct optical communication with the receiving device.

2. The method for concealed optical communication based on a reflecting surface according to claim 1, characterized in that, Step S1 specifically includes: S11: Determine the installation position on the ceiling, use a light-emitting diode capable of intensity modulation as the transmitting light source, and install the transmitting light source at the installation position; S12: Use a photodiode as the receiving device, set up the receiving device and the intelligent reflecting surface within the communication range, and there is also an eavesdropping device within the communication range.

3. The method for covert optical communication based on a reflecting surface according to claim 1, wherein Step S2 specifically includes: S21: Determine the peak power of the transmitting light source and the optical signal vector transmitted, and determine the optical transmission communication conditions according to the peak power and the optical signal vector; S22: Conduct initial optical communication according to the optical transmission communication conditions, calculate the channel gain including the direct-link channel gain and the reflection-link channel gain, obtain the additive white Gaussian noise, and obtain the optical communication signal representation through the additive white Gaussian noise and the channel gain.

4. The method for covert optical communication based on a reflecting surface according to claim 1, wherein Step S3 specifically includes: S31: Respectively obtain the eavesdropping signal representation under signal transmission and the eavesdropping signal representation under no signal transmission based on binary hypothesis testing and the optical communication signal representation, so as to obtain the probability density function of the eavesdropping signal representation passing the detection; S32: Obtain the relative entropy of the probability density function of the eavesdropping signal representation passing the detection and obtain the concealment threshold, so as to construct the concealment constraint; S33: Calculate the key threshold, calculate the eavesdropping key threshold and the communication key threshold, determine the key threshold bound according to the eavesdropping key threshold and the communication key threshold. When the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint.

5. The method for covert optical communication based on a reflecting surface according to claim 1, wherein Step S4 specifically includes: S41: Calculate the sum of the channel gains. Through the sum of the channel gains and performing a ceiling operation, obtain the ceiling equation; S42: Construct the first and second concealment parameter equations according to the ceiling equation and solve them to obtain the first concealment parameter and the concealment probability matrix respectively, and use the first concealment parameter and the concealment probability matrix as the concealment parameters. S43: When the key threshold is less than the key threshold bound, substitute the concealment parameters into the ceiling equation, obtain the second information entropy through the ceiling equation, perform probability density function integration according to the first concealment parameter to obtain the second variance, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint.

6. The method for concealed optical communication based on a reflecting surface according to claim 1, wherein In step S5, after constructing the multivariate optimization equation, first fix the peak power, perform proximity selection and reflected spot search according to the peak power to obtain the first optimal communication parameter, then fix the first optimal communication parameter and solve for the peak power to obtain the optimal peak power, and use the optimal peak power and the first optimal communication parameter as the optimal communication parameter.

7. A reflective-surface-based covert optical communication system for performing the reflective-surface-based covert optical communication method according to any one of claims 1 to 6, characterized in that, Including: Communication device setting module: used to obtain the transmitting light source and determine the setting position, set the transmitting light source at the setting position, and set the receiving device and the intelligent reflecting surface. Optical communication signal representation module: used to determine the optical transmission communication conditions, perform primary optical communication according to the optical transmission communication conditions and calculate the channel gain, and obtain the optical communication signal representation through the channel gain. First concealment constraint module: used to obtain the eavesdropping signal representation according to binary hypothesis testing and the optical communication signal representation, construct the concealment constraint through the concealment threshold and the eavesdropping signal representation, calculate the key threshold and determine the key threshold bound, and when the key threshold is greater than the key threshold bound, obtain the first concealment constraint by finding the first variance and the first information entropy in the concealment constraint. Second concealment constraint module: used to obtain the channel gain sum, obtain the concealment parameters through the channel gain sum and perform the ceiling operation of the maximum upper bound and equation construction. When the key threshold is less than the key threshold bound, calculate the second information entropy and the second variance according to the concealment parameters, and substitute the second information entropy and the second variance into the concealment constraint to obtain the second concealment constraint. Parameter optimization module: used to use the first concealment constraint and the second concealment constraint as the concealment constraints, construct a multivariate optimization equation through the concealment constraints, perform piecewise solution of the multivariate optimization equation through the concealment constraints to obtain the optimal communication parameters, and control the transmitting light source and the intelligent reflecting surface according to the optimal communication parameters to perform optical communication with the receiving device.

8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the reflection surface-based covert optical communication method according to any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the reflection surface-based covert optical communication method according to any one of claims 1 to 6.

10. A computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, characterized in that, When the program instructions are executed by the computer, the computer can execute the steps of the reflection surface-based covert optical communication method according to any one of claims 1 to 6.

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