STAR-RIS network security performance prediction method under active eavesdropping

Abstract

The invention relates to the technical field of communication security, and discloses an STAR-RIS network security performance prediction method, system and device under active eavesdropping and a medium. An STAR-RIS network model under active eavesdropping is constructed; acquiring a first legal signal received by the legal user and a second legal signal eavesdropped by the active eavesdropping user; determining a signal-to-noise ratio of the first legal signal and the second legal signal; acquiring a probability density function of equivalent channel gains of the legal channel and the eavesdropping channel by adopting gamma distribution; obtaining a probability density function of a signal-to-noise ratio of the first legal signal and the second legal signal; and obtaining the probability of STAR-RIS network security interruption under the active eavesdropping so as to realize the prediction of STAR-RIS network security performance.

Description

Technical Field

[0001] The present invention relates to the field of network security technology, and in particular to a STAR-RIS network security performance prediction method, system, device and medium under active eavesdropping. Background Art

[0002] Reconfigurable Intelligent Surface (RIS) has high spectrum and energy efficiency and is considered one of the key technologies of the sixth generation mobile communication system. Traditional RIS only has reflection function and cannot serve users at the back of RIS, and can only achieve half coverage. Therefore, a RIS that can simultaneously transmit and reflect (STAR) is proposed. STAR-RIS can serve users at the back of RIS through transmission, thus achieving full coverage.

[0003] In order to improve network security, STAR-RIS is introduced into wireless networks. There may be eavesdroppers in the STAR-RIS network, which will affect the security performance of the STAR-RIS network. However, the current STAR-RIS network only considers the passive eavesdropper situation. In actual networks, there are often active eavesdroppers. Unlike passive eavesdroppers who can only eavesdrop on information passively, active eavesdroppers will actively send interference information to disrupt legitimate communications while eavesdropping on information, posing a greater security threat. Therefore, it is particularly important to predict the security performance of the STAR-RIS network under active eavesdropping. Summary of the invention

[0004] The object of the present invention is to provide a method, system, device and medium for predicting the security performance of a STAR-RIS network under active eavesdropping, so as to realize the security performance prediction of a STAR-RIS network under active eavesdropping.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for predicting the security performance of a STAR-RIS network under active eavesdropping, wherein the STAR-RIS network under active eavesdropping includes: a base station, a legitimate user, an active eavesdropping user, and a STAR-RIS device having a plurality of transmission units and a plurality of reflection units; the active eavesdropping user and the base station are located on the same side of the STAR-RIS device, the active eavesdropping user is directly connected to the base station, the legitimate user is located on the other side of the STAR-RIS device, and the legitimate user is connected to the base station through the STAR-RIS device;

[0006] Among them, the legitimate user is used to receive the legitimate signal sent by the base station through the STAR-RIS device, the active eavesdropping user is used to eavesdrop on and interfere with the legitimate signal sent by the base station to the legitimate user, and the STAR-RIS device is used to enhance the legitimate channel for the legitimate user to receive the legitimate signal and weaken the eavesdropping channel for the active eavesdropping user to eavesdrop on the legitimate signal;

[0007] The method comprises:

[0008] Respectively obtain a first legitimate signal received by a legitimate user and a second legitimate signal eavesdropped by an active eavesdropping user in a STAR-RIS network under active eavesdropping, and respectively determine a signal-to-noise ratio of the first legitimate signal and the second legitimate signal through the phase of a transmission unit and a reflection unit in the STAR-RIS;

[0009] According to the signal-to-noise ratio of the first legal signal and the second legal signal, a probability density function of equivalent channel gains of the legal channel and the wiretap channel is obtained by using a gamma distribution;

[0010] According to the probability density functions of the equivalent channel gains of the legitimate channel and the wiretap channel, and the relationship between the signal-to-noise ratio and the equivalent channel gain, respectively obtaining the probability density functions of the signal-to-noise ratio of the first legitimate signal and the second legitimate signal;

[0011] According to the probability density function of the signal-to-noise ratio of the first legal signal and the second legal signal, a closed expression of the probability of security interruption of the STAR-RIS network under active wiretapping is obtained, so as to predict the security performance of the STAR-RIS network under active wiretapping through the closed expression of the probability of security interruption of the STAR-RIS network.

[0012] In some optional embodiments, the first legitimate signal received by the legitimate user is:

[0013]

[0014] The second legitimate signal eavesdropped by the active eavesdropping user is:

[0015]

[0016] Where P A and P J Respectively represent the transmission power of the base station and the active eavesdropping user, x A Indicates the legal signal sent by the base station, x J is the interference signal sent by the active eavesdropping user, x A and x J is the preset energy normalized signal, h an 、h nb 、h ne and h ae Respectively represent A→Rn Link, R n →B link, R n The complex channel coefficients of the A→E link and the A→E link, A represents the base station, B represents the legitimate user, E represents the active eavesdropping user, R n represents the nth reflection unit / transmission unit in the STAR-RIS device, N represents the total number of STAR-RIS reflection and transmission units, and the complex channel coefficient h an 、h nb 、h ne and h ae The shape factor and expansion factor are (m ar ,Ω ar )、(m rb ,Ω rb )、(m re ,Ω re ) and (m ae ,Ω ae ) of the Nakagami-m random distribution, j 2 =-1 represents an imaginary number, θ t,n ∈[0,2π) and θ r,n ∈[0,2π) represent the phase of the nth transmission unit and reflection unit respectively, N t and N r Respectively represent the number of transmission units and reflection units, and N t +N r =N, η∈[0,1] represents the interference power of the active eavesdropping user caused by full-duplex communication and the active eavesdropping user's transmission power P J The ratio of n b and n e They represent the noise when the legitimate user receives the legitimate signal and the active eavesdropping user eavesdrops on the legitimate signal, n b and n e The noise power is N0.

[0017] In some optional embodiments, the phase of the transmission unit in the STAR-RIS device is:

[0018]

[0019] The phase of the reflection unit in the STAR-RIS device is:

[0020]

[0021] The signal-to-noise ratio of the first legal signal is:

[0022]

[0023] The signal-to-noise ratio of the second legal signal is:

[0024]

[0025] In the formula, ∠h an ,∠h nb ,∠h ne and ∠h ae Denote the complex channel coefficient h an 、h nb 、h ne and h ae The phase of |h an |、|h nb |、|h ne | and |h ae | respectively represent the complex channel coefficient h an 、h nb 、h ne and h ae The amplitude of γ = P A / N0 represents the average signal-to-noise ratio of the base station, γ J =P J / N0 represents the average interference-to-noise ratio of active eavesdropping users, is the equivalent channel gain of the legal channel, is the equivalent channel gain of the interference channel when the active eavesdropping user interferes with the legitimate user, is the equivalent channel gain of the eavesdropping channel, Y obeys exponential distribution, and the probability density function of Y is

[0026] In some optional embodiments, the probability density function of the equivalent channel gain of the legal channel is:

[0027]

[0028] The probability density function of the equivalent channel gain Z of the eavesdropping channel is:

[0029]

[0030] In the formula, represents the gamma function, is the inverse scale parameter of X, is the shape parameter of X, is the inverse scale parameter of Z, is the shape parameter of Z, μ X (k) represents the kth moment of X, μ Z (k) represents the k-th moment of Z;

[0031] μ X (k) and μZ (k) are respectively expressed as:

[0032]

[0033] In the formula,

[0034] In some optional embodiments, the signal-to-noise ratio γ of the first legal signal b The probability density function of is:

[0035]

[0036] The signal-to-noise ratio of the second legal signal is γ e The probability density function of is:

[0037]

[0038] In the formula,

[0039] In some optional embodiments, the probability of STAR-RIS network security interruption under active wiretapping is calculated by the security rate C of the STAR-RIS network. s It is expressed as the probability of falling below the predetermined safety rate R;

[0040] The security rate of the STAR-RIS network is:

[0041] C s (γ b ,γ e )=(log2(1+γ b )-log2(1+γ e )) + ;

[0042] Where (x) + =max(x,0) means taking the maximum value between x and 0;

[0043] The security interruption probability of the STAR-RIS network under active eavesdropping is approximately expressed as:

[0044]

[0045] Where Pr[·] represents the probability of safe interruption, δ = 2 R A preset threshold value for safety interruption;

[0046] Will γ b and γ e Substitute the probability density function of γ into it, and b Integrate and we get:

[0047]

[0048] Make variable substitution After that, the probability of STAR-RIS network security interruption under active eavesdropping is:

[0049]

[0050] In the formula, Ψ(·,·;·) is the Tricomi confluence hypergeometric function.

[0051] The embodiment of the present invention also provides a STAR-RIS network security interruption prediction system under active eavesdropping, wherein the STAR-RIS network under active eavesdropping includes: a base station, a legitimate user, an active eavesdropping user, and a STAR-RIS device having a plurality of transmission units and a plurality of reflection units; the active eavesdropping user and the base station are located on the same side of the STAR-RIS device, the active eavesdropping user is directly connected to the base station, the legitimate user is located on the other side of the STAR-RIS, and the legitimate user is connected to the base station through the STAR-RIS device;

[0052] Among them, the legitimate user is used to receive the legitimate signal sent by the base station through the STAR-RIS device, the active eavesdropping user is used to eavesdrop on and interfere with the legitimate signal sent by the base station to the legitimate user, and the STAR-RIS device is used to enhance the legitimate channel for the legitimate user to receive the legitimate signal and weaken the eavesdropping channel for the active eavesdropping user to eavesdrop on the legitimate signal;

[0053] The system comprises:

[0054] A signal-to-noise ratio acquisition module is used to respectively acquire a first legitimate signal received by a legitimate user and a second legitimate signal eavesdropped by an active eavesdropping user in a STAR-RIS network under active eavesdropping, and to respectively determine the signal-to-noise ratios of the first legitimate signal and the second legitimate signal through the phases of a transmission unit and a reflection unit in the STAR-RIS;

[0055] A first function building module is used to obtain a probability density function of an equivalent channel gain of a legitimate channel and a wiretap channel by using a gamma distribution according to a signal-to-noise ratio of the first legitimate signal and the second legitimate signal;

[0056] A second function construction module is used to obtain probability density functions of the signal-to-noise ratio of the first legal signal and the second legal signal respectively according to the probability density functions of the equivalent channel gains of the legal channel and the wiretap channel, and the relationship between the signal-to-noise ratio and the equivalent channel gain;

[0057] The security performance prediction module is used to obtain a closed expression of the probability of STAR-RIS network security interruption under active eavesdropping according to the probability density function of the signal-to-noise ratio of the first legal signal and the second legal signal, so as to predict the security performance of the STAR-RIS network under active eavesdropping through the closed expression of the probability of STAR-RIS network security interruption.

[0058] An embodiment of the present invention also provides a computer device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned STAR-RIS network security performance prediction method under active eavesdropping.

[0059] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned STAR-RIS network security performance prediction method under active eavesdropping.

[0060] The STAR-RIS network security performance prediction method under active eavesdropping provided by the present invention has at least the following beneficial effects:

[0061] The present invention takes into account the existence of active eavesdroppers that pose a greater security threat in a STAR-RIS network. Therefore, according to a STAR-RIS network including a base station, a legitimate user, an active eavesdropping user and a STAR-RIS device, by obtaining a legitimate signal received by a legitimate user and a legitimate signal eavesdropped by an active eavesdropping user, the signal-to-noise ratio of the link corresponding to the two is determined, and then the probability distribution of the equivalent channel gain of the link corresponding to the two and the probability distribution of the signal-to-noise ratio of the link corresponding to the two are obtained. Finally, the closed expression of the probability of security interruption of the STAR-RIS network is determined through the probability distribution of the link signal-to-noise ratio, so as to characterize the security performance of the STAR-RIS network.

[0062] Because the security interruption probability refers to the performance indicator of the system when the legitimate users cannot securely receive information at the predetermined rate, the closed expression of the security interruption probability can be used to predict the security interruption probability of the STAR-RIS network under different network configurations, eavesdropper strategies and system parameters, thereby effectively realizing the security performance prediction of the STAR-RIS network under active eavesdropping. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] One or more embodiments are exemplarily described by the pictures in the corresponding drawings, and these exemplary descriptions do not constitute limitations on the embodiments.

[0064] Figure 1is a schematic diagram of a STAR-RIS network under active eavesdropping provided according to an embodiment of the present invention;

[0065] Figure 2 It is a flowchart of a method for predicting STAR-RIS network security performance under active eavesdropping provided according to an embodiment of the present invention;

[0066] Figure 3 1 is a curve diagram showing a theoretical value and a simulated value of a safety interruption probability according to an embodiment of the present invention. Figure 1 ;

[0067] Figure 4 1 is a curve diagram showing a theoretical value and a simulated value of a safety interruption probability according to an embodiment of the present invention. Figure 2 . DETAILED DESCRIPTION

[0068] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present invention can be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0069] One embodiment of the present invention relates to a method for predicting the network performance of a STAR-RIS network under active eavesdropping. In this embodiment, the structure of the STAR-RIS network under active eavesdropping is as follows: Figure 1 As shown, it includes: base station Alice (A), legal user Bob (B), active eavesdropping user Eve (E), and a STAR-RIS device with multiple reflection units and multiple transmission units. Eve is located in the reflection area (same side) of the STAR-RIS device, and Bob is located in the transmission area (back side) of the STAR-RIS device. In this embodiment, it is assumed that the direct link between Alice and Bob is blocked, while Alice and Eve have a direct link, that is, the active eavesdropping user is directly connected to the base station, and the legal user is connected to the base station through the STAR-RIS device.

[0070] Among them, legitimate users are used to receive legitimate signals sent by base stations through STAR-RIS devices, active eavesdropping users are used to eavesdrop on and interfere with legitimate signals sent by base stations to legitimate users, and STAR-RIS devices are used to enhance legitimate channels for legitimate users to receive legitimate signals and weaken eavesdropping channels for active eavesdropping users to eavesdrop on legitimate signals.

[0071] The base station and the legitimate user are both equipped with a single antenna, while the active eavesdropping user is equipped with two antennas and works in full-duplex mode, one of which is used to passively eavesdrop on legitimate information, and the other is used to actively transmit interference information to disrupt legitimate communications. The number of transmission units and reflection units in the STAR-RIS device is N, and the nth reflection unit / transmission unit of the STAR-RIS device is denoted by R n , Using h an 、h ae 、h ne and h nb Respectively represent A→R n Link, A→E Link, R n →E link and R n → Complex channel coefficient of link B. Complex channel coefficient of all links: h an 、h ae 、h ne and h nb , The shape factor and expansion factor are (m ar ,Ω ar )、(m rb ,Ω rb )、(m re ,Ω re ) and (m ae ,Ω ae )’s Nakagami-m random distribution.

[0072] The following is a detailed description of the implementation details of the STAR-RIS network security performance prediction method under active eavesdropping of this embodiment. The following content is only provided for the convenience of understanding the implementation details and is not necessary for the implementation of this solution.

[0073] The specific process of the STAR-RIS network security performance prediction method under active eavesdropping in this embodiment can be as follows: Figure 2 As shown, including:

[0074] Step 201, respectively obtain a first legitimate signal received by a legitimate user and a second legitimate signal eavesdropped by an active eavesdropping user in a STAR-RIS network under active eavesdropping, and respectively determine the signal-to-noise ratio of the first legitimate signal and the second legitimate signal through the phase of a transmission unit and a reflection unit in the STAR-RIS.

[0075] See Figure 1 In the STAR-RIS network architecture shown, the first legitimate signal received by the legitimate user is:

[0076]

[0077] The second legitimate signal eavesdropped by the active eavesdropping user is:

[0078]

[0079] Where P A and P J Respectively represent the transmission power of the base station and the active eavesdropping user, x A Indicates the legal signal sent by the base station, x J is the interference signal sent by the active eavesdropping user, x A and x J is the preset energy normalized signal, h an 、h nb 、h ne and h ae Respectively represent A→R n Link, R n →B link, R n The complex channel coefficients of the A→E link and the A→E link, A represents the base station, B represents the legitimate user, E represents the active eavesdropping user, R n represents the nth reflection unit / transmission unit in the STAR-RIS device, N represents the total number of STAR-RIS reflection and transmission units, and the complex channel coefficient h an 、h nb 、h ne and h ae The shape factor and expansion factor are (m ar ,Ω ar )、(m rb ,Ω rb )、(m re ,Ω re ) and (m ae ,Ω ae ) of the Nakagami-m random distribution, j 2 =-1 represents an imaginary number, θ t,n ∈[0,2π) and θ r,n ∈[0,2π) represent the phase of the nth transmission unit and reflection unit respectively, N t and N r Respectively represent the number of transmission units and reflection units, and N t +N r =N, η∈[0,1] represents the interference power of the active eavesdropping user caused by full-duplex communication and the active eavesdropping user's transmission power P J The ratio of n b and n e They represent the noise when the legitimate user receives the legitimate signal and the active eavesdropping user eavesdrops on the legitimate signal, n b and ne The noise power is N0.

[0080] In the specific implementation, in order to simultaneously enhance the received signal of the legitimate user B (i.e., the first legitimate signal) and suppress the received signal of the active eavesdropping user E (i.e., the second legitimate signal), the phase values ​​of the transmission unit and the reflection unit in the STAR-RIS device are respectively:

[0081]

[0082] At this time, the signal-to-noise ratio of the received signals of B and E can be expressed as:

[0083]

[0084] In the formula, ∠h an ,∠h nb ,∠h ne and ∠h ae Denote the complex channel coefficient h an 、h nb 、h ne and h ae The phase of |h an |、|h nb |、|h ne | and |h ae | respectively represent the complex channel coefficient h an 、h nb 、h ne and h ae The amplitude of γ = P A / N0 represents the average signal-to-noise ratio of the base station, γ J =P J / N0 represents the average interference-to-noise ratio of active eavesdropping users, is the equivalent channel gain of the legal channel, is the equivalent channel gain of the interference channel when the active eavesdropping user interferes with the legitimate user, is the equivalent channel gain of the eavesdropping channel, Y obeys exponential distribution, and the probability density function of Y is

[0085] Step 202: According to the signal-to-noise ratio of the first legal signal and the second legal signal, a probability density function of the equivalent channel gain of the legal channel and the wiretap channel is obtained by using a gamma distribution.

[0086] Specifically, the equivalent channel gain X of the legal channel and the equivalent channel gain Z of the eavesdropping channel are approximated by gamma distribution, and the probability density function of the equivalent channel gain of the legal channel is obtained as follows:

[0087]

[0088] The probability density function of the equivalent channel gain Z of the eavesdropping channel is:

[0089]

[0090] In the formula, represents the gamma function, is the inverse scale parameter of X, is the shape parameter of X, is the inverse scale parameter of Z, is the shape parameter of Z, μ X (k) represents the kth moment of X, μ Z (k) represents the k-th moment of Z;

[0091] μ X (k) and μ Z (k) are respectively expressed as:

[0092]

[0093] In the formula,

[0094] Step 203: Obtain probability density functions of the signal-to-noise ratios of the first legal signal and the second legal signal respectively according to the probability density functions of the equivalent channel gains of the legal channel and the wiretap channel and the relationship between the signal-to-noise ratio and the equivalent channel gain.

[0095] Among them, the signal-to-noise ratio of the first legal signal is γ b The probability density function of is:

[0096]

[0097] The signal-to-noise ratio of the second legal signal is γ e The probability density function of is:

[0098]

[0099] In the formula,

[0100] Step 204, according to the probability density function of the signal-to-noise ratio of the first legitimate signal and the second legitimate signal, obtain a closed expression for the probability of STAR-RIS network security interruption under active wiretapping, so as to predict the security performance of the STAR-RIS network under active wiretapping through the closed expression for the probability of STAR-RIS network security interruption.

[0101] Specifically, the safety rate is the maximum information rate at which legal sending and receiving nodes can maintain safe communication, which is defined as the legal user channel capacity C b and the eavesdropping user channel capacity Ce The difference between the two values ​​is the probability of STAR-RIS network outage under active eavesdropping, which is calculated by the security rate C of the STAR-RIS network. s It is expressed as the probability of falling below a predetermined safe rate R.

[0102] The security rate C of the STAR-RIS network s It can be expressed as:

[0103] C s (γ b ,γ e )=(C b -C e ) + =(log2(1+γ b )-log2(1+γ e )) + ;

[0104] Where (x) + =max(x,0) means taking the maximum value of variables x and 0.

[0105] The security interruption probability of the STAR-RIS network under active eavesdropping is approximately expressed as:

[0106]

[0107] Where Pr[·] represents the probability of safe interruption, δ = 2 R The preset threshold for safety interruption.

[0108] Put γ b and γ e Substitute the probability density function of into the approximate expression of the safety interruption probability, and we can get b Integrate and get the SOP expression:

[0109]

[0110] Make variable substitution The final expression of SOP (i.e. the closed expression of STAR-RIS network security outage probability) can be derived:

[0111]

[0112] In the formula, Ψ(·,·;·) is the Tricomi confluence hypergeometric function.

[0113] In an example, the following simulation is performed to verify the theoretical expression of the safety interruption probability. The simulation parameters are set as follows: For a two-dimensional planar network topology, the coordinates of Alice, Bob, STAR-RIS and Eve are (0, 0), (10, 0), (Rx, Ry) and (6, 2), respectively. The relationship between the complex channel expansion factor and the path loss is: and Among them, d ar d rb d re and d ae are the distances from Alice to STAR-RIS, STAR-RIS to Bob, STAR-RIS to Eve, and Alice to Eve, τ ar =τ rb =τ re =τ ae =2 is the path loss factor. Rx = 8, Ry = 0, m ar =m rb =2,m ae =m re =1, N=100, γ=10dB, R=0.1bps / Hz, eta=0.1.

[0114] Figure 3 The curve diagram of the theoretical value and simulation value of the safety interruption probability when the number of transmission units of STRAT-RIS in this embodiment changes. It can be found from the figure that the theoretical value and the simulation value match perfectly, which proves the correctness and accuracy of the theoretical expression of the present invention. In addition, the results in the figure also show that the safety interruption probability increases with γ J increases with the increase of γ J The larger the value, the greater the interference of active eavesdropping users to legitimate users. In addition, the fixed interference-to-noise ratio γ J , the probability of security interruption will increase with the increase of the number of STRAT-RIS transmission units. This is because the more transmission units there are, the greater the signal-to-noise ratio of Bob's reception will be. This shows that the number of STRAT-RIS transmission units can be increased to counter active eavesdroppers and ensure system security.

[0115] Figure 4It is a curve diagram of the theoretical value and simulation value of the safety interruption probability when the coordinates of STRAT-RIS change in the embodiment. Three ways of changing the STRAT-RIS coordinates are considered in the figure: 1) changing along the x-axis between B and E; 2) changing along the upper semicircular arc with a center of (8,0) and a radius of 2; 3) changing along the lower semicircular arc with a center of (8,0) and a radius of 2. It can be seen from the figure that when STAR-RIS is located at coordinates (9.9,0), (9.9,0.6) and (9.3,1.5), the safety interruption probability of the system in the corresponding mode is minimized. This is because, when the STRAT-RIS coordinates are located at the above positions, STRAT-RIS can simultaneously meet the dual conditions of being closest to B and farthest from E in the corresponding mode. This provides theoretical guidance for the optimal layout position of STAR-RIS in real networks.

[0116] In this embodiment, the existence of active eavesdroppers with greater security threats in the STAR-RIS network is taken into consideration. Therefore, according to the STAR-RIS network including base stations, legal users, active eavesdropping users and STAR-RIS devices, the signal-to-noise ratio of the links corresponding to the two is determined by obtaining the legal signals received by the legal users and the legal signals eavesdropped by the active eavesdropping users, and then the probability distribution of the equivalent channel gain of the links corresponding to the two and the probability distribution of the signal-to-noise ratio of the links corresponding to the two are obtained. Finally, the closed expression of the probability of security interruption of the STAR-RIS network is determined by the probability distribution of the link signal-to-noise ratio, so as to characterize the security performance of the STAR-RIS network. Because the security interruption probability refers to the performance index of the system when the legal user cannot safely receive information at a predetermined rate, the closed expression of the security interruption probability can be used to predict the security interruption probability of the STAR-RIS network under different network configurations, eavesdropper strategies and system parameters, thereby effectively realizing the security performance prediction of the STAR-RIS network under active eavesdropping.

[0117] The step division of the various methods above is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the protection scope of the present invention. Adding insignificant modifications or introducing insignificant designs to the algorithm or process without changing the core design of the algorithm and process are all within the protection scope of the invention.

[0118] Another embodiment of the present invention relates to a STAR-RIS network security performance prediction system under active eavesdropping. The implementation details of the STAR-RIS network security performance prediction system under active eavesdropping of this embodiment are specifically described below. The following content is only the implementation details provided for easy understanding and is not necessary for implementing this solution.

[0119] The STAR-RIS network under active eavesdropping in this embodiment includes: a base station, a legitimate user, an active eavesdropping user, and a STAR-RIS device having multiple transmission units and multiple reflection units; the active eavesdropping user and the base station are located on the same side of the STAR-RIS device, the active eavesdropping user is directly connected to the base station, and the legitimate user is located on the other side of the STAR-RIS, and the legitimate user is connected to the base station through the STAR-RIS device.

[0120] Among them, legitimate users are used to receive legitimate signals sent by base stations through STAR-RIS devices, active eavesdropping users are used to eavesdrop on and interfere with legitimate signals sent by base stations to legitimate users, and STAR-RIS devices are used to enhance legitimate channels for legitimate users to receive legitimate signals and weaken eavesdropping channels for active eavesdropping users to eavesdrop on legitimate signals.

[0121] The STAR-RIS network security performance prediction system under active eavesdropping of this embodiment includes:

[0122] The signal-to-noise ratio acquisition module is used to respectively acquire the first legitimate signal received by the legitimate user and the second legitimate signal eavesdropped by the active eavesdropping user in the STAR-RIS network, and determine the signal-to-noise ratio of the first legitimate signal and the second legitimate signal respectively through the phase of the transmission unit and the reflection unit in the STAR-RIS.

[0123] The first function building module is used to obtain the probability density function of the equivalent channel gain of the legal channel and the wiretap channel by using the gamma distribution according to the signal-to-noise ratio of the first legal signal and the second legal signal.

[0124] The second function construction module is used to obtain the probability density functions of the signal-to-noise ratio of the first legal signal and the second legal signal respectively according to the probability density functions of the equivalent channel gains of the legal channel and the wiretap channel, and the relationship between the signal-to-noise ratio and the equivalent channel gain.

[0125] The security performance prediction module is used to obtain a closed expression of the probability of STAR-RIS network security interruption under active eavesdropping according to the probability density function of the signal-to-noise ratio of the first legal signal and the second legal signal, so as to predict the security performance of the STAR-RIS network under active eavesdropping through the closed expression of the probability of STAR-RIS network security interruption.

[0126] It is not difficult to find that this embodiment is a system embodiment corresponding to the above method embodiment, and this embodiment can be implemented in conjunction with the above method embodiment. The relevant technical details and technical effects mentioned in the above embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above embodiment.

[0127] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.

[0128] Another embodiment of the present invention relates to a computer device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the STAR-RIS network security performance prediction method under active eavesdropping in the above-mentioned embodiments.

[0129] Among them, the memory and the processor are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors and memories together. The bus can also connect various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor is transmitted on a wireless medium via an antenna, and further, the antenna also receives data and transmits the data to the processor.

[0130] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

[0131] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0132] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as: ROM), random access memory (Random Access Memory, referred to as: RAM), disk or optical disk and other media that can store program codes.

[0133] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for predicting the security performance of STAR-RIS network under active eavesdropping, characterized in that: The STAR-RIS network under active eavesdropping includes: a base station, a legitimate user, an active eavesdropping user, and a STAR-RIS device having a plurality of transmission units and a plurality of reflection units; the active eavesdropping user and the base station are located on the same side of the STAR-RIS device, the active eavesdropping user is directly connected to the base station, the legitimate user is located on the other side of the STAR-RIS device, and the legitimate user is connected to the base station through the STAR-RIS device; Among them, the legitimate user is used to receive the legitimate signal sent by the base station through the STAR-RIS device, the active eavesdropping user is used to eavesdrop on and interfere with the legitimate signal sent by the base station to the legitimate user, and the STAR-RIS device is used to enhance the legitimate channel for the legitimate user to receive the legitimate signal and weaken the eavesdropping channel for the active eavesdropping user to eavesdrop on the legitimate signal; The method comprises: Respectively obtain a first legitimate signal received by a legitimate user and a second legitimate signal eavesdropped by an active eavesdropping user in a STAR-RIS network under active eavesdropping, and respectively determine a signal-to-noise ratio of the first legitimate signal and the second legitimate signal through the phase of a transmission unit and a reflection unit in the STAR-RIS; According to the signal-to-noise ratio of the first legal signal and the second legal signal, a probability density function of equivalent channel gains of the legal channel and the wiretap channel is obtained by using a gamma distribution; According to the probability density functions of the equivalent channel gains of the legitimate channel and the wiretap channel, and the relationship between the signal-to-noise ratio and the equivalent channel gain, respectively obtaining the probability density functions of the signal-to-noise ratio of the first legitimate signal and the second legitimate signal; According to the probability density function of the signal-to-noise ratio of the first legal signal and the second legal signal, a closed expression of the probability of security interruption of the STAR-RIS network under active wiretapping is obtained, so as to predict the security performance of the STAR-RIS network under active wiretapping through the closed expression of the probability of security interruption of the STAR-RIS network.

2. The method for predicting the network security performance of STAR-RIS under active eavesdropping according to claim 1 is characterized in that: The first legal signal received by the legal user is: The second legitimate signal eavesdropped by the active eavesdropping user is: Where P A and P J Respectively represent the transmission power of the base station and the active eavesdropping user, x A Indicates the legal signal sent by the base station, x J is the interference signal sent by the active eavesdropping user, x A and x J is the preset energy normalized signal, h an 、h nb 、h ne and h ae Respectively represent A→R n Link, R n →B link, R n The complex channel coefficients of the A→E link and the A→E link, A represents the base station, B represents the legitimate user, E represents the active eavesdropping user, R n represents the nth reflection unit / transmission unit of STAR-RIS, N represents the total number of reflection and transmission units in the STAR-RIS device, and the complex channel coefficient h an 、h nb 、h ne and h ae The shape factor and expansion factor are (m ar ,Ω ar )、(m rb ,Ω rb )、(m re ,Ω re ) and (m ae ,Ω ae ) of the Nakagami-m random distribution, j 2 =-1 represents an imaginary number, θ t,n ∈[0,2π) and θ r,n ∈[0,2π) represent the phase of the nth transmission unit and reflection unit respectively, N t and N r Respectively represent the number of transmission units and reflection units, and N t +N r =N, η∈[0,1] represents the interference power of the active eavesdropping user caused by full-duplex communication and the active eavesdropping user's transmission power P J The ratio of n b and n e They represent the noise when the legitimate user receives the legitimate signal and the active eavesdropping user eavesdrops on the legitimate signal, n b and n e The noise power is N0.

3. The STAR-RIS network security performance prediction method under active eavesdropping according to claim 2 is characterized in that: The phase of the transmission unit in the STAR-RIS device is: The phase of the reflection unit in the STAR-RIS device is: The signal-to-noise ratio of the first legal signal is: The signal-to-noise ratio of the second legal signal is: In the formula, ∠h an ,∠h nb ,∠h ne and ∠h ae Denote the complex channel coefficient h an 、h nb 、h ne and h ae The phase of |h an |、|h nb |、|h ne | and |h ae | respectively represent the complex channel coefficient h an 、h nb 、h ne and h ae The amplitude of γ = P A / N0 represents the average signal-to-noise ratio of the base station, γ J =P J / N0 represents the average interference-to-noise ratio of active eavesdropping users, is the equivalent channel gain of the legal channel, is the equivalent channel gain of the interference channel when the active eavesdropping user interferes with the legitimate user, is the equivalent channel gain of the eavesdropping channel, Y obeys exponential distribution, and the probability density function of Y is λ=N t Ω rb Ω re .

4. The method for predicting the network security performance of STAR-RIS under active eavesdropping according to claim 3 is characterized in that: The probability density function of the equivalent channel gain X of the legal channel is: The probability density function of the equivalent channel gain Z of the eavesdropping channel is: In the formula, represents the gamma function, is the inverse scale parameter of X, is the shape parameter of X, is the inverse scale parameter of Z, is the shape parameter of Z, μ X (k) represents the kth moment of X, μ Z (k) represents the k-th moment of Z; μ X (k) and μ Z (k) are respectively expressed as: In the formula, 5. The method for predicting the network security performance of STAR-RIS under active eavesdropping according to claim 4 is characterized in that: The signal-to-noise ratio γ of the first legal signal b The probability density function of is: The signal-to-noise ratio of the second legal signal is γ e The probability density function of is: In the formula, 6. The method for predicting the network security performance of STAR-RIS under active eavesdropping according to claim 5 is characterized in that: The probability of STAR-RIS network interruption under active eavesdropping is calculated by the security rate C of the STAR-RIS network. s It is expressed as the probability of falling below the predetermined safety rate R; The security rate of the STAR-RIS network is: C s (c b ,c e )=(log2(1+γ b )-log2(1+γ e )) + ; Where (x) + =max(x,0) means taking the maximum value between x and 0; The security interruption probability of the STAR-RIS network under active eavesdropping is approximately expressed as: Where Pr[·] represents the probability of safe interruption, δ = 2 R A preset threshold value for safety interruption; Will γ b and γ e Substituting the probability density function of γ b Integrate and we get: Make variable substitution After that, the probability of STAR-RIS network security interruption under active eavesdropping is: In the formula, Ψ(·,·;·) is the Tricomi confluence hypergeometric function.

7. A STAR-RIS network security performance prediction system under active eavesdropping, characterized in that: The STAR-RIS network under active eavesdropping includes: a base station, a legitimate user, an active eavesdropping user, and a STAR-RIS device having a plurality of transmission units and a plurality of reflection units; the active eavesdropping user and the base station are located on the same side of the STAR-RIS device, the active eavesdropping user is directly connected to the base station, the legitimate user is located on the other side of the STAR-RIS, and the legitimate user is connected to the base station through the STAR-RIS device; Among them, the legitimate user is used to receive the legitimate signal sent by the base station through the STAR-RIS device, the active eavesdropping user is used to eavesdrop on and interfere with the legitimate signal sent by the base station to the legitimate user, and the STAR-RIS device is used to enhance the legitimate channel for the legitimate user to receive the legitimate signal and weaken the eavesdropping channel for the active eavesdropping user to eavesdrop on the legitimate signal; The system comprises: A signal-to-noise ratio acquisition module is used to respectively acquire a first legitimate signal received by a legitimate user and a second legitimate signal eavesdropped by an active eavesdropping user in a STAR-RIS network under active eavesdropping, and to respectively determine the signal-to-noise ratios of the first legitimate signal and the second legitimate signal through the phases of a transmission unit and a reflection unit in the STAR-RIS; A first function building module is used to obtain a probability density function of an equivalent channel gain of a legitimate channel and a wiretap channel by using a gamma distribution according to a signal-to-noise ratio of the first legitimate signal and the second legitimate signal; A second function construction module is used to obtain probability density functions of the signal-to-noise ratio of the first legal signal and the second legal signal respectively according to the probability density functions of the equivalent channel gains of the legal channel and the wiretap channel, and the relationship between the signal-to-noise ratio and the equivalent channel gain; The security performance prediction module is used to obtain a closed expression of the probability of STAR-RIS network security interruption under active eavesdropping according to the probability density function of the signal-to-noise ratio of the first legal signal and the second legal signal, so as to predict the security performance of the STAR-RIS network under active eavesdropping through the closed expression of the probability of STAR-RIS network security interruption.

8. A computer device, characterized in that: include: at least one processor; And, a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the STAR-RIS network security performance prediction method under active eavesdropping as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the STAR-RIS network security performance prediction method under active eavesdropping according to any one of claims 1 to 6 is implemented.

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