Method for evaluating security of visible light and radio frequency hybrid system based on slipt

Abstract

The application discloses a visible light and radio frequency hybrid system security evaluation method based on wireless information energy simultaneous transmission SLIPT, and mainly solves the problem of incomplete security evaluation of the existing visible light and radio frequency hybrid system.The implementation scheme is as follows: a transmitting end sends visible light signals to legal users and a relay; the relay separates a direct current component from the received visible light signals by using a wireless information energy simultaneous transmission mode, collects energy, and sends the radio frequency signal to the legal users; a plurality of non-collusion eavesdroppers eavesdrop the information of the radio frequency link; the security outage probability SOP and the effective secrecy throughput EST of the system are calculated according to the signal-to-noise ratios of the legal users and the eavesdroppers; and the security performance of the system is evaluated according to whether the two evaluation conditions that the SOP is less than 1 and the EST is greater than 0 are simultaneously satisfied.The application expands the system coverage by fusing the visible light and radio frequency systems, can obtain the optimal parameter setting in terms of security, improves the security performance of the system, and can be used for indoor visible light communication system design.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and specifically relates to a security assessment method for a hybrid visible light (VL) and radio frequency (RF) system, which can be used in the design of indoor visible light communication systems. Background Technology

[0002] Visible light communication (VLC) technology has become a research hotspot in the field of communications due to its advantages such as wide spectrum resources, high transmission speed, and absence of electromagnetic interference. However, VLC technology still faces some challenges in practical applications, such as limited coverage area, high dependence on line-of-sight transmission, and susceptibility to communication link disruptions. These factors limit its application scope in communication systems. Meanwhile, radio frequency (RF) technology, although limited by spectrum resources, boasts a wider coverage area and stronger penetration, which to some extent compensates for the shortcomings of VLC technology. Therefore, combining the high-speed transmission characteristics of VLC with the wide coverage advantage of RF to construct a hybrid visible light / radio frequency (VL / RF) network has become a new trend in communications research, aiming to fully utilize the complementary advantages of the two technologies to improve overall network performance.

[0003] With wireless communication technology permeating all levels of society, public awareness of personal privacy and data security is increasing. VLC and RF, as two key technologies in wireless communication, offer convenience for legitimate users due to their open signal propagation characteristics, but also create vulnerabilities that can be exploited by potential cyber attackers, potentially leading to the leakage of sensitive information and increased cybersecurity threats. To effectively address this challenge, Physical Layer Security (PLS) technology has emerged. Based on fundamental principles of information theory, this technology utilizes the time-varying, random, and reciprocal physical properties of wireless channels to amplify the channel condition differences between legitimate communication links and illicit eavesdropping links, providing a new protection mechanism for network security.

[0004] In their paper "PLS analysis in an indoor heterogeneous VLC / RF network based on known and unknown CSI," Kumar et al. investigated the physical layer security issues in indoor environments where VLC and RF technologies coexist. They prevented eavesdropping attacks by imposing a positive security rate constraint and evaluated system security performance based on average security capacity, connection interruption probability, and security interruption probability. However, this model, because both RF and VLC transmission elements are located at the transmitter and no relay transmission is used, limits signal coverage and enhancement capabilities. Furthermore, the lack of SLIPT (Simultaneous Information and Energy Transmission) technology results in low system energy efficiency and weak anti-interference capabilities. Additionally, the system only considers the case of a single eavesdropper, failing to adequately account for the complexity and potential security threats posed by multiple eavesdroppers in high-density user environments, thus limiting its widespread applicability.

[0005] Vats et al., in their paper "Physical layer security for dual-hop VLC / RF communication systems," investigated the security performance of a dual-hop hybrid VL / RF system. In this system, data signals are first transmitted via a single-source antenna through a decoded-and-forward method to a relay R via a radio frequency channel. The relay R decodes the received radio frequency signal, converting it into an optical signal, which is then transmitted via a VLC channel to the authorized receiving antenna at the destination. However, in this system, legitimate users only receive the relayed VL signal, while eavesdroppers directly intercept the RF signal from the base station. Furthermore, its design, which uses the radio frequency base station as the signal source, is not suitable for security assessments of indoor VLC systems using LEDs as the signal source, thus limiting its applicability and effectiveness in modern indoor optical communication environments.

[0006] In their research, "Performance Analysis of a Hybrid Visible Light / Radio Frequency Cooperative Communication System Based on SLIPT," Zhang Zhixuan et al. proposed a hybrid VL / RF cooperative communication system based on SLIPT. This system divides the end-to-end link into a VLC link and an RF communication link by relaying data, assuming a randomly moving off-network relay exists within the light source's coverage area. However, this system fails to adequately consider the presence of unauthorized eavesdroppers, thus hindering accurate analysis of the system's physical layer security performance. Furthermore, the model's application is limited to situations where legitimate users are outside the VLC illumination coverage area, thus restricting its applicability in a wider range of environments and its ability to comprehensively assess security. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing a method for safety evaluation of a hybrid visible light (VL) and radio frequency (RF) system, thereby improving system safety performance, energy efficiency, and anti-interference capabilities.

[0008] The technical approach to achieving the objective of this invention is as follows: by integrating VL and RF communication systems, the system's coverage area is expanded and signal transmission capabilities are enhanced, effectively reducing inter-cell interference and thus improving the system's anti-interference capability. By employing SLIPT (Simultaneous Information and Energy Transmission) technology at the relay point, the DC component is separated from the received optical signal, energy is harvested, and then transmitted as an RF signal, achieving synchronous transmission of energy and information, improving the system's energy efficiency, and consequently enhancing the system's physical layer security performance.

[0009] Based on the above ideas, the implementation scheme of the present invention includes the following steps:

[0010] 1. A security assessment method for a visible light and radio frequency hybrid system based on SLIPT, the system comprising a transmitter S consisting of multiple light-emitting diodes (LEDs), a relay R, a legitimate user D equipped with both a photodetector PD and an antenna, and multiple non-colluding eavesdroppers E positioned outside the illumination coverage of the transmitter S. k Its characteristic is that it includes the following steps:

[0011] 1) Transmitter S sends visible light VL signals to legitimate user D and relay R. Calculate the channel gain h between transmitter S and legitimate user D in the visible light communication VLC link. SD The channel gain h between the relay R and the relay R SR And according to h SD Calculate the signal-to-noise ratio γ of legitimate user D on the VLC link. SD ;

[0012] 2) Relay R uses the SLIPT (Simultaneous Information and Energy Transmission) method to separate the DC component from the received visible light (VL) signal, harvests the energy, and transmits it as a radio frequency (RF) signal to legitimate user D and multiple non-colluding eavesdroppers E. k Eavesdropping on information in the radio frequency (RF) link;

[0013] 3) Calculate the received optical signal y of legitimate user D on the RF link. RD and multiple non-conspirator E k The received optical signal y RE,k And calculate the signal-to-noise ratio γ of legitimate user D on the RF link. RD and multiple non-conspirator E k signal-to-noise ratio γ RE,k ;

[0014] 4) Based on the signal-to-noise ratio γ of legitimate user D in the VLC link SD The signal-to-noise ratio γ of legitimate user D on the RF link RD Calculate the total signal-to-noise ratio γ of legitimate user D. D ;

[0015] 5) According to non-conspirator E k Signal-to-noise ratio γ RE,k Calculate the probability density function f of its distribution. γ (γ RE,k ) and cumulative distribution function F γ (γ RE,k And calculate the total signal-to-noise ratio γ of the eavesdropper in the transmitter-relay-eavesdropper SRE link. E ;

[0016] 6) Based on the total signal-to-noise ratio γ of legitimate user D D Total signal-to-noise ratio γ of the eavesdropper E The safe interruption probability SOP of the calculation system is: SOP = Pr{1+γ} D ≤T(1+γ E )}, where Pr{·} represents the probability of a certain event, C th Indicates the system target rate;

[0017] 7) Based on the safety interruption probability SOP and target rate C th The effective secure throughput of the computing system is EST: EST = C th ×(1-SOP);

[0018] 8) Determine the security performance of the visible light and radio frequency hybrid system based on the two parameters: Security Outage Probability (SOP) and Effective Confidential Throughput (EST).

[0019] If the SOP value is less than 1 and the EST value is greater than 0, then the system is safe.

[0020] If any one of the conditions is not met, the system is not secure.

[0021] 9) Simulate the security interruption probability (SOP) and effective confidentiality throughput (EST) of the system under different parameter settings, and select the system parameters with the minimum SOP value and the maximum EST value as the parameter settings for the best security performance of the visible light and radio frequency hybrid system.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] First, by integrating visible light (VLC) and radio frequency (RF) communication systems, this invention fully utilizes the respective advantages of VLC and RF communication to achieve a high degree of resource complementarity and optimized configuration. This not only expands the system's coverage but also significantly enhances signal transmission capabilities, effectively reduces inter-cell interference, and thus enhances the system's anti-interference capabilities.

[0024] Secondly, since the present invention uses the wireless information-energy simultaneous transmission (SLIPT) method to process the visible light VL signal received by the relay R, it can provide the required energy to the receiving end while transmitting information. This synchronous transmission mechanism can effectively improve energy utilization efficiency and reduce energy loss.

[0025] Third, by simulating a scenario where multiple eavesdroppers are eavesdropping simultaneously, this invention not only enhances the real-world adaptability of the system design but also significantly improves the system's ability to respond to complex security threats, making the system design more in line with the needs of practical applications and diverse scenarios, thereby enhancing the system's practicality and adaptability.

[0026] Fourth, by simulating the system security interruption probability SOP and effective confidentiality throughput EST under different system parameter settings when there are multiple non-colluding eavesdroppers, this invention can obtain the parameter settings with the best security performance by comparing and selecting them. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0028] Figure 1 This is a flowchart illustrating the implementation of the present invention;

[0029] Figure 2 This is a model diagram of the visible light and radio frequency hybrid system based on wireless information and energy transmission SLIPT in this invention;

[0030] Figure 3 To simulate the present invention at different distances d from the eavesdropper to the relay. E The system safety interruption probability SOP varies with the emission power P of a single light-emitting diode (LED). LED Change curve graph;

[0031] Figure 4 To simulate the present invention at different distances d from the eavesdropper to the relay. E The effective secure throughput EST of the lower system varies with the target rate C th Change curve graph;

[0032] Figure 5To simulate the system security interruption probability SOP of this invention under different legal user activity radius L, the emission power P of a single light-emitting diode (LED) is calculated. LED Change curve graph;

[0033] Figure 6 To simulate the system's effective security throughput EST as a function of the target rate C under different legal user activity radius L, this invention is proposed. th Change curve graph;

[0034] Figure 7 To simulate the system safety interruption probability SOP of this invention under different photoelectric conversion coefficients ρ of the photodetector PD, as a function of the emission power P of a single light-emitting diode (LED). LED Change curve graph;

[0035] Figure 8 To simulate the system's effective security throughput EST as a function of the target rate C under different photodetector (PD) photoelectric conversion coefficients ρ, this invention... th Change curve graph;

[0036] Figure 9 To simulate the system safety interruption probability SOP of this invention under different numbers of light-emitting diodes (LEDs) N, and how it varies with the emission power P of a single LED. LED Change curve graph;

[0037] Figure 10 To simulate the system's effective security throughput EST as a function of the target rate C under different numbers of light-emitting diodes (LEDs) N, this invention... th Change curve graph. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0039] Reference Figure 1 This example is based on the SLIPT-based security assessment method for hybrid visible light and radio frequency systems. The implementation steps are as follows:

[0040] Step 1: Construct a visible light and radio frequency hybrid system based on SLIPT.

[0041] The visible light and radio frequency hybrid system constructed in this example includes a transmitter S, a relay R, a legitimate user D, and multiple non-colluding eavesdroppers E. k The transmitter S consists of N light-emitting diodes (LEDs), the legitimate user D is equipped with a photodetector (PD) and an antenna, and multiple non-colluding eavesdroppers E... k All are located outside the S-beam illumination coverage area of ​​the transmitting end.

[0042] Figure 2 This is a model diagram of a visible light and radio frequency hybrid system based on SLIPT (Simultaneous Transmission of Information and Energy) in this example, where d SD d represents the distance from transmitter S to legitimate user D. D Let L represent the distance from legitimate user D to relay R, L represent the radius of the area where legitimate user D can move, L1 represent the radius of the illumination coverage area of ​​transmitter S, H represent the distance from transmitter S to relay R, and d represent the distance from transmitter S to relay R. E,k E, a non-conspirator eavesdropper k Distance to relay R.

[0043] Step 2: Generate a visible light communication (VLC) link.

[0044] Transmitter S uses N×P LED The transmit power is used to send visible light VL signals to legitimate user D and relay R, where N is the total number of light-emitting diodes (LEDs) at the transmitter S, and P... LED The emission power of a single light-emitting diode (LED);

[0045] When legitimate user D and relay R receive the visible light VL signal, they generate a visible light communication VLC link SD between the transmitter and the legitimate user, and a visible light communication VLC link SR between the transmitter and the relay.

[0046] Step 3: Calculate the channel gain h between the transmitter S and the legitimate user D in the visible light communication (VLC) links SD and SR, respectively. SD and the channel gain h between the transmitter S and the relay R SR .

[0047] 3.1) Calculate the channel gain h between the transmitter S and the legitimate user D on the SD link. SD :

[0048]

[0049] Where m represents the Lambert emission coefficient, A r d represents the effective emitting area of ​​the photodetector PD. SD This represents the distance from the transmitter S to the legitimate user D. ψ is the radiation angle at transmitter S, ψ is the incident angle of photodetector PD at legitimate user D, and T is the radiation angle at transmitter S. s (ψ) is the gain of the optical filter in the photodetector PD, and g(ψ) is the gain of the condenser in the photodetector PD;

[0050] 3.2) Calculate the channel gain h between the transmitter S and the relay R on the SR link. SR :

[0051]

[0052] Where H represents the distance from the transmitter S to the relay R.

[0053] Step 4: Calculate the signal-to-noise ratio γ of legitimate user D on the visible light communication (VLC) link SD. SD .

[0054] Based on the channel gain h between the transmitter S and the legitimate user D on the visible light communication (VLC) link SD. SD Calculate the signal-to-noise ratio γ of legitimate user D on the SD link. SD :

[0055]

[0056] Where ρ represents the photoelectric conversion efficiency of the photodetector PD, N represents the total number of light-emitting diodes (LEDs) at the emitter S, and P LED The value represents the emitted light power of a single LED, where A represents the peak amplitude of the modulated power signal, and h represents the emitted light power. SD Let S be the channel gain between the transmitter S and the legitimate user D, and N0 represent the noise power of the legitimate user D.

[0057] Step 5: Relay energy collection generates RF links RD and RE, and a visible light-RF hybrid link SRE. The received optical signal y of legitimate user D on the RD link is calculated respectively. RD And RE link multiple non-colluding eavesdroppers E k The received optical signal y RE,k .

[0058] 5.1) The relay R uses the wireless information-energy simultaneous transmission (SLIPT) method to separate the DC component y from the received visible light VL signal. dc (t);

[0059] 5.2) Based on the segmented DC component y dc (t) Calculate the energy E collected by relay R. R :

[0060] E R =fy dc V oc (T1+T2),

[0061] Where f is the fill factor, V oc T1 is the open-circuit voltage of the photodetector PD, T2 is the duration for the transmitter S to send the visible light VL signal to the relay R, and T3 is the duration for the relay R to transmit the data to the receiver.

[0062] 5.3) The relay R is based on the collected energy E R With transmission power P RSend radio frequency (RF) signals to legitimate user D, where P R =E R / T2;

[0063] 5.4) Legitimate user D receives RF signals, and multiple non-colluding eavesdroppers E... k By eavesdropping on the radio frequency (RF) signal, an RF link RD is generated between the relay and the legitimate user, an RF link RE is generated between the relay and the eavesdropper, and a visible light-RF hybrid link SRE is generated between the transmitter, the relay, and the eavesdropper.

[0064] 5.5) Based on the transmit power P of relay R R Calculate the received optical signal y of legitimate user D on the RF link RD. RD :

[0065]

[0066] Where d D Let η represent the distance from legitimate user D to relay R, and h represent the path loss coefficient of the RF link. RD represents the RF link gain between relay R and legitimate user D, s is the transmitted signal of relay R, and n1 represents additive white Gaussian noise with a mean of 0 and a variance of N1.

[0067] 5.6) Based on the transmit power P of relay R R Calculate the number of non-colluding eavesdroppers E on the radio frequency (RF) link RE. k The received optical signal y RE,k :

[0068]

[0069] Where d E,k E, a non-conspirator eavesdropper k The distance to relay R, h RE,k This indicates that relay R connects to non-colluding eavesdropper E. k The RF link gain between them, where n2 represents additive white Gaussian noise with a mean of 0 and a variance of N2.

[0070] Step 6: Calculate the signal-to-noise ratio γ of legitimate user D in RF link RD. RD and multiple non-colluding eavesdroppers E on the radio frequency link RE k signal-to-noise ratio γ RE,k And the total signal-to-noise ratio γ of legitimate user D across the two links. D .

[0071] 6.1) Based on the received optical signal y of legitimate user D on the RF link RD RD Calculate the signal-to-noise ratio γ of legitimate user D in RF link RD.RD :

[0072]

[0073] Where P R h represents the transmit power of the RF link. RD d represents the RF link gain between relay R and legitimate user D. D Let η be the distance from legitimate user D to relay R, η be the path loss coefficient of the RF link, and N1 be the variance of additive white Gaussian noise of legitimate user D.

[0074] 6.2) Based on multiple non-colluding eavesdroppers E on the radio frequency (RF) link RE k The received optical signal y RE,k Calculate the radio frequency link RE for multiple non-colluding eavesdroppers E k signal-to-noise ratio γ RE,k :

[0075]

[0076] Where h RE,k This indicates that relay R connects to non-colluding eavesdropper E. k RF link gain between, d E,k E, a non-conspirator eavesdropper k The distance to relay R, N2 is the distance of the non-colluding eavesdropper E. k The variance of additive white Gaussian noise;

[0077] 6.3) Based on the signal-to-noise ratio γ of the legitimate user D in the visible light communication (VLC) link SD SD The signal-to-noise ratio γ of the legitimate user D in the RF link RD RD The total signal-to-noise ratio γ of the legitimate user D across the two links was calculated. D :

[0078] γ D =γ SD +γ RD .

[0079] Step 7, calculate the RF link RE and multiple non-colluding eavesdroppers E. k signal-to-noise ratio γ RE,k The probability density function f of the distribution γ (γ RE,k ) and cumulative distribution function F γ (γ RE,k ).

[0080] 7.1) Based on the radio frequency (RF) link RE, multiple non-colluding eavesdroppers E k signal-to-noise ratio γ RE,k Calculate the RF RE link channel gain hRE,k The square of |h RE,k 2 :

[0081]

[0082] Where d E,k E, a non-conspirator eavesdropper k The distance to relay R, η is the path loss coefficient of the RF link, and N2 is the distance of the non-colluding eavesdropper E. k The variance of additive white Gaussian noise, P R This refers to the transmit power of the radio frequency (RF) link.

[0083] 7.2) Calculate |h RE,k 2 Regarding γ RE,k The derivative:

[0084]

[0085] 7.3) Based on the characteristic that the RF link RE follows independent Rayleigh fading, calculate the distance from the relay R to the non-colluding eavesdropper E. k RF link gain h RE,k Square | h RE,k 2 The probability density function:

[0086]

[0087] Where g RE,k It is the square of the RF RE link channel gain |h RE,k 2 Expectations;

[0088] 7.4) According to |h RE,k 2 probability density function and |h RE,k 2 Regarding γ RE,k The derivative of |h RE,k 2 (γ RE,k )', calculate γ RE,k The probability density function f of the distribution γ (γ RE,k ):

[0089]

[0090] 7.5) According to non-conspirator E k Signal-to-noise ratio γ RE,k probability density function f γ (γ RE,k ), calculate γRE,k The cumulative distribution function F of the distribution γ (γ RE,k ):

[0091]

[0092] Step 8: Calculate the total signal-to-noise ratio γ of the visible light-RF hybrid link SRE eavesdropper. E .

[0093] 8.1) Set up multiple non-colluding eavesdroppers E k Given that they are located on the same radius and have the same link distance to relay R, calculate the non-colluding eavesdropper E in the RF link. k Total signal-to-noise ratio γ RE :

[0094] γ RE =max{γ RE,1 ,γ RE,2 ,…,γ RE,k ,…,γ RE,M}

[0095] Where k∈{1,2,…,M},γ RE,1 For the signal-to-noise ratio of the non-conspirator E1, γ RE,2 For the signal-to-noise ratio of E2 (non-conspirator eavesdropper), γ RE,k E, a non-conspirator eavesdropper k The signal-to-noise ratio, γ RE,M E, a non-conspirator eavesdropper M The signal-to-noise ratio, M is the signal-to-noise ratio of the non-colluding eavesdropper E. k The total number;

[0096] 8.2) Based on the signal-to-noise ratio γ of the relay R in the visible light communication (VLC) link. SR and non-colluding eavesdroppers on RF links E k Total signal-to-noise ratio γ RE Calculate the total signal-to-noise ratio γ of the SRE link eavesdropper. E :

[0097] γ E =min{γ SR ,γ RE}

[0098] Where, γ SR =V max V max For visible light communication (VLC) links, the signal-to-noise ratio (SNR) of legitimate users (D) is γ. SD The maximum value.

[0099] Step 9, based on the total signal-to-noise ratio γ of legitimate user D. D Total signal-to-noise ratio γ of the eavesdropper EThe standard operating procedure (SOP) for the probability of safe interruption of a computing system.

[0100] 9.1) The existing definition of the security interruption probability SOP = Pr{1+γ D ≤T(1+γ E This can be further transformed into the following formula:

[0101]

[0102] Where Pr{·} represents the probability of a certain event. C th γ represents the system's target rate. D For the total signal-to-noise ratio of legitimate user D, γ E The total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link;

[0103] 9.2) Based on the total signal-to-noise ratio γ of legitimate user D D Calculate its probability density function f γ (γ D ):

[0104]

[0105] in All are intermediate variables; V min V max The signal-to-noise ratio (SNR) of legitimate users in a visible light communication (VLC) link is γ. SD The minimum and maximum values, d D Let η be the distance from legitimate user D to relay R, η represent the path loss coefficient of the RF link, N1 be the variance of the additive white Gaussian noise of legitimate user D, and P be the distance from legitimate user D to relay R. R The RF link transmits power, L represents the radius of the range where a legitimate user D can operate, m represents the Lambertian emission coefficient, H represents the distance from the transmitter S to the relay R, ρ represents the photoelectric conversion efficiency of the photodetector PD, N represents the total number of LEDs at the transmitter S, and P represents the transmit power of the RF link. LED The value represents the emitted light power of a single LED, A represents the peak amplitude of the modulated power signal, and N0 represents the noise power of the legitimate user D. r T represents the effective emitting area of ​​the photodetector PD. s (ψ) represents the gain of the optical filter at the photodetector PD, and g(ψ) represents the gain of the concentrator at the photodetector PD.

[0106] 9.3) Based on the total signal-to-noise ratio γ of the transmitter-relay-eavesdropper SRE link, the eavesdropper... E Calculate its cumulative distribution function F γ (γ E ):

[0107]

[0108] in d E,k E, a non-conspirator eavesdropper k The distance to relay R, N2 is the distance of the non-colluding eavesdropper E. k The variance of additive white Gaussian noise, g RE,k Indicates non-conspirator E k The expected channel power gain, M is the value of the non-colluding eavesdropper E. k The total number;

[0109] 9.4) Calculate γ E Pick Cumulative distribution function of total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link.

[0110]

[0111] 9.5) Using the probability density function f of the total signal-to-noise ratio of the legitimate user D obtained in step 9.2), γ (γ D The cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link obtained in step 9.4) and step 9.5) Solving probability problems The process can be transformed into solving the integral as follows:

[0112]

[0113] 9.6) Substitute the result of step 9.5) into step 9.1) to calculate the system safety interruption probability SOP:

[0114]

[0115] Step 10: Calculate the effective confidential throughput EST of the system, and determine the security performance of the visible light and radio frequency hybrid system based on the parameter EST and the security interruption probability SOP.

[0116] 10.1) Based on the safety interruption probability SOP and the system-set target rate C th Effective secure throughput of the computing system (EST):

[0117] EST=C th ×(1-SOP);

[0118] 10.2) Set the threshold values ​​for Security Outage Probability (SOP) and Effective Confidential Throughput (EST) to 1 and 0 respectively, and perform an initial security performance assessment:

[0119] If the SOP value is less than 1 and the EST value is greater than 0, then the system is safe and proceed to step 10.3.

[0120] If any one of the conditions is not met, the system is not secure.

[0121] 10.3) Simulate the security interruption probability (SOP) and effective confidentiality throughput (EST) of the system under different parameter settings, and select the system parameters with the minimum SOP value and the maximum EST value as the parameter settings for the best security performance of the visible light and radio frequency hybrid system.

[0122] The effects of this invention can be further illustrated by the following simulation results.

[0123] I. Simulation Conditions

[0124] Condition 1. The emission power P of a single light-emitting diode (LED) at the emitter S. LED The value is set to 0.1-0.7W, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the distance from the eavesdropper to the relay is d. E =7,d E =9,d E =11;

[0125] Condition 2. Safe rate C th The range is set to 0-10, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the distance from the eavesdropper to the relay is d. E =7,d E =9,d E =11;

[0126] Condition 3. The emission power P of a single light-emitting diode (LED) at the emitter S. LED Set to 0.1-0.7W, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the radius of the legal user's activity range is L=4, L=5, L=6;

[0127] Condition 4. Safe speed C th Set to 0-10, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the radius of the legal user's activity range is L=4, L=5, L=6;

[0128] Condition 5. The emission power P of a single light-emitting diode (LED) at the emitter S. LED The W value is set to 0.1-0.7W, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the photoelectric conversion coefficient of the photodetector PD is ρ=0.5, ρ=0.6, ρ=0.7.

[0129] Condition 6. Safe Rate C thThe range is set to 0-10, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the photoelectric conversion coefficient of the photodetector PD is ρ=0.5, ρ=0.6, ρ=0.7.

[0130] Condition 7. The emission power P of a single light-emitting diode (LED) at the emitter S. LED The power is set to 0.1-0.7W, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the number of LEDs is N=13, N=15, N=17.

[0131] Condition 8. Safe Rate C th Set to 0-10, the number of non-colluding eavesdroppers is M=1, M=3, M=5, and the number of LEDs is N=13, N=15, N=17.

[0132] II. Simulation Content and Results

[0133] Simulation 1 simulates the system's security interruption probability SOP under the parameter settings of condition 1, i.e., the distance d from different eavesdroppers to the relay. E The system safety interruption probability SOP varies with the emission power P of a single light-emitting diode (LED). LED Changes, such as Figure 3 As shown.

[0134] from Figure 3 It can be seen that under all given parameter settings, the system SOP is less than 1; for all d E With P LED As the number of non-colluding eavesdroppers M increases, the system's standard operating procedures (SOPs) gradually decrease, and the system's security performance improves; when the number of non-colluding eavesdroppers M is the same, for the same P... LED d E The larger the value, the smaller the system SOP value, and the better the system security performance; as the number of non-colluding eavesdroppers M increases, the SOP value increases, and the system security performance deteriorates.

[0135] Simulation 2: Under the parameter settings of condition 2, the effective secure throughput EST of the simulated system is shown in the following results. Figure 4 As shown.

[0136] from Figure 4 It can be seen that, under all given parameter settings, the system EST is greater than 0; for all d E With C th As the number of eavesdroppers (M) increases, EST first reaches a peak and then gradually decreases, indicating that the system security performance initially improves and then deteriorates. With an increase in the number of eavesdroppers (M), the system EST decreases, and the system security performance worsens. When the number of non-colluding eavesdroppers (M) is the same, for the same C... th With d E As the value of EST increases, the system's security performance improves.

[0137] Simulation 3, under the parameter settings of condition 3, simulates the system's safe interruption probability SOP. The results are as follows: Figure 5 As shown.

[0138] from Figure 5 It can be seen that, under all given parameter settings, the system SOP is less than 1; for all L, as P... LED As the number of non-colluding eavesdroppers M increases, the value of the system's Standard Operating Procedure (SOP) gradually decreases, resulting in improved system security. When the number of non-colluding eavesdroppers M is the same, for the same P... LED As the value of L decreases, the system SOP decreases, and the system security performance improves; as the number of non-colluding eavesdroppers M increases, the SOP value increases, and the system security performance deteriorates.

[0139] Simulation 4: Under the parameter settings of condition 4, the effective secure throughput EST of the simulated system is shown in the following results. Figure 6 As shown.

[0140] from Figure 6 It can be seen that, under all given parameter settings, the system EST is greater than 0; for all L, as C... th As the number of non-colluding eavesdroppers M increases, the value of system EST first increases and then decreases, indicating that system security performance first improves and then deteriorates; when the number of non-colluding eavesdroppers M is the same, for the same C th As the value of L decreases, the system EST increases, and the system security performance improves; as the number of non-colluding eavesdroppers M increases, the EST value decreases, and the system security performance deteriorates.

[0141] Simulation 5 simulates the system's safe interruption probability (SOP) under the parameter settings of condition 5. The results are as follows: Figure 7 As shown.

[0142] from Figure 7 It can be seen that under all given parameter settings, the system SOP is less than 1; for all ρ, increasing P LED The value of P decreases the system SOP, which can lead to higher system security; when the number of non-colluding eavesdroppers M is the same, for the same P LED As ρ increases, the system SOP value decreases, and the system security performance improves; as the number of non-colluding eavesdroppers M increases, the SOP value increases, and the system security performance deteriorates.

[0143] Simulation 6: Under the parameter settings of condition 6, the effective secure throughput EST of the simulated system is shown in the following results. Figure 8 As shown.

[0144] from Figure 8 It can be seen that, under all given parameter settings, the system EST is greater than 0; for all ρ, as C... thAs the number of non-colluding eavesdroppers M increases, the value of system EST first increases and then decreases, indicating that system security performance first improves and then deteriorates; when the number of non-colluding eavesdroppers M is the same, for the same C th As the value of ρ increases, the system EST increases, and the system security performance improves; as the number of non-colluding eavesdroppers M increases, the EST value decreases, and the system security performance deteriorates.

[0145] Simulation 7 simulates the system's safe interruption probability (SOP) under the parameter settings of condition 7. The results are as follows: Figure 9 As shown.

[0146] from Figure 9 It can be seen that under all given parameter settings, the system SOP is less than 1; for all N, increasing P... LED The value of P decreases the system SOP, which can lead to higher system security; when the number of non-colluding eavesdroppers M is the same, for the same P LED As N increases, the system's SOP value decreases, and the system's security performance improves; as the number of non-colluding eavesdroppers M increases, the SOP value increases, and the system's security performance deteriorates.

[0147] Simulation 8: Under the parameter settings of condition 8, the effective secure throughput EST of the simulated system is shown in the figure. Figure 10 As shown.

[0148] from Figure 10 It can be seen that, under all given parameter settings, the system EST is greater than 0; for all N, as C... th As the number of non-colluding eavesdroppers M increases, the value of system EST first increases and then decreases, indicating that system security performance first improves and then deteriorates; when the number of non-colluding eavesdroppers M is the same, for the same C th As the value of N increases, the system EST increases, and the system security performance improves; as the number of non-colluding eavesdroppers M increases, the EST value decreases, and the system security performance deteriorates.

[0149] The simulation results above demonstrate that the SLIPT-based security assessment method for visible light and radio frequency hybrid systems proposed in this invention expands the scope of comprehensive security assessment in existing research and provides a new physical layer security enhancement scheme for visible light and radio frequency hybrid systems.

[0150] The above description is merely a specific example of the present invention and does not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and details without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

[0151] It should be noted that the step numbers in the specification and claims of this invention are only for the purpose of clearly describing the embodiments of this invention and facilitating understanding, and their order is not limited.

Claims

1. A security assessment method for a visible light and radio frequency hybrid system based on SLIPT, the system comprising a transmitter S consisting of multiple light-emitting diodes (LEDs), a relay R, a legitimate user D equipped with both a photodetector PD and an antenna, and multiple non-colluding eavesdroppers positioned outside the illumination coverage of the transmitter S. Its characteristics are, Includes the following steps: 1) Transmitter S sends visible light VL signals to legitimate user D and relay R. Calculate the channel gain between transmitter S and legitimate user D on the visible light communication VLC link. Channel gain between and relay R and according to Calculate the signal-to-noise ratio of legitimate user D on the VLC link. ; 2) Relay R uses the SLIPT (Simultaneous Information and Energy Transmission) method to separate the DC component from the received visible light (VL) signal, harvests the energy, and transmits it as a radio frequency (RF) signal to the legitimate user D, while multiple non-colluding eavesdroppers... Eavesdropping on information in the radio frequency (RF) link; 3) Calculate the received optical signal of legitimate user D on the RF link. and multiple non-conspirators Received optical signal And calculate the signal-to-noise ratio of legitimate user D on the RF link. and multiple non-conspirators signal-to-noise ratio The calculation of the received optical signal of legitimate user D The implementation steps include the following: 3a) The relay R uses the wireless information-energy simultaneous transmission (SLIPT) method to separate the DC component from the received photocurrent and then harvest the energy. : ； in As the fill factor, This represents the DC portion of the signal. This is the open-circuit voltage of the photodetector PD; This indicates the duration of the first time slot, during which the transmitter S sends a visible light VL signal to the relay R. This indicates the duration of the second time slot, in which time slot... In this process, the relay R uses the collected energy to transmit data to the receiving end via a radio frequency (RF) link; 3b) Based on the energy collected by relay R Calculate the transmit power of the RF link: ; 3c) Based on transmission power Calculate the optical signal received by legitimate user D. : ， in The distance from legitimate user D to relay R. This represents the path loss coefficient of the radio frequency (RF) link. This represents the RF link gain between relay R and legitimate user D. It is the transmission signal of relay R. This indicates that the mean is 0 and the variance is... Additive white Gaussian noise; 4) Based on the signal-to-noise ratio of legitimate user D on the VLC link Signal-to-noise ratio of legitimate user D on the RF link Calculate the total signal-to-noise ratio of legitimate user D. ; 5) Based on non-conspirator eavesdropping Signal-to-noise ratio Calculate the probability density function of its distribution. and cumulative distribution function And calculate the total signal-to-noise ratio of the eavesdropper in the transmitter-relay-eavesdropper SRE link. ; 6) Based on the total signal-to-noise ratio of legitimate user D Total signal-to-noise ratio with eavesdropper Standard Operating Procedure (SOP) for Safe Outage Probability in Computing Systems: ， in Represents the probability of a certain event. , Indicates the system target rate; The probability of a safe interruption in the computing system is determined by transforming the probability problem into an integral problem, and the implementation steps include the following: 6a) The probability of security interruption Further transformed into the following formula: ， in Represents the probability of a certain event. , Indicates the system target rate. The total signal-to-noise ratio for legitimate user D. The total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link; 6b) Based on the total signal-to-noise ratio of legitimate user D Calculate its probability density function : ， in , , , , , The signal-to-noise ratio (SNR) of legitimate users in a visible light communication (VLC) link is as follows: The minimum and maximum values, The distance from legitimate user D to relay R. This represents the path loss coefficient of the radio frequency (RF) link. The variance of additive white Gaussian noise for legitimate user D. For the transmit power of the radio frequency (RF) link, This represents the radius of the area where a legitimate user D can move freely. Represents the Lambert emission coefficient. This represents the distance from the transmitter S to the relay R. This indicates the photoelectric conversion efficiency of the photodetector (PD). This indicates the total number of light-emitting diodes (LEDs) at the emitter S. This represents the emitted light power of a single LED. This represents the peak amplitude of the modulated power signal. This represents the noise power of legitimate user D. This indicates the effective emitting area of ​​the photodetector (PD). This represents the gain of the optical filter at the photodetector (PD). This indicates the gain of the concentrator at the photodetector PD; 6c) Based on the total signal-to-noise ratio of the eavesdropper in the transmitter-relay-eavesdropper SRE link. Calculate its cumulative distribution function. : ， in , Non-conspirator eavesdropper Distance to relay R, Non-conspirator eavesdropper The variance of additive white Gaussian noise Indicates non-conspirator eavesdropper Expected channel power gain Non-conspirator eavesdropper The total number; 6d) Calculation Pick Cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link. : ， 6e) Using the probability density function of the total signal-to-noise ratio of the legitimate user D obtained in step 6b). The cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link obtained in step 6d) Solving probability problems The process can be transformed into solving the integral as follows: ； 6f) Substitute the result of step 6e) into step 6a) to calculate the system safety interruption probability SOP: ； 7) Based on the safety interruption probability SOP and target rate Effective secure throughput of the computing system: EST ; 8) Determine the security performance of the visible light and radio frequency hybrid system based on the two parameters: Security Outage Probability (SOP) and Effective Confidential Throughput (EST). If the SOP value is less than 1 and the EST value is greater than 0, then the system is safe. If any one of the conditions is not met, the system is insecure; 9) Simulate the security interruption probability (SOP) and effective confidentiality throughput (EST) of the system under different parameter settings, and select the system parameters with the minimum SOP value and the maximum EST value as the parameter settings for the best security performance of the visible light and radio frequency hybrid system.

2. The method according to claim 1, characterized in that, In step 1), the transmitter S is calculated to be respectively connected to the legal... Channel gain between users D Channel gain between and relay R The formula is as follows: ， ， in, Represents the Lambert emission coefficient. This indicates the effective emitting area of ​​the photodetector (PD). This represents the distance from the transmitter S to the legitimate user D. It is the radiation angle of the transmitter S. It is the incident angle of the photodetector PD at point D, which is the location of the legitimate user. This represents the gain of the optical filter in a photodetector (PD). This represents the gain of the concentrator in a photodetector (PD). This represents the distance from the transmitter S to the relay R.

3. The method according to claim 1, characterized in that, Step 1) calculates the signal-to-noise ratio of legitimate user D on the VLC link. The formula is as follows: ， in This indicates the photoelectric conversion efficiency of the photodetector (PD). This indicates the total number of light-emitting diodes (LEDs) at the emitter S. This represents the emitted light power of a single LED. This represents the peak amplitude of the modulated power signal. The channel gain between transmitter S and legitimate user D. This represents the noise power of the legitimate user D.

4. The method according to claim 1, characterized in that, Step 3) calculates multiple non-colluding eavesdroppers Received optical signal The formula is as follows: ， in For the transmit power of the radio frequency (RF) link, Non-conspirator eavesdropper Distance to relay R, This represents the path loss factor of the radio frequency (RF) link. Indicates relay R to non-colluding eavesdroppers RF link gain between It is the transmission signal of relay R. This indicates that the mean is 0 and the variance is... Additive white Gaussian noise.

5. The method according to claim 1, characterized in that, Step 3) calculates the signal-to-noise ratio of legitimate user D on the RF link. and multiple non-conspirators signal-to-noise ratio The formula is as follows: ， ， in For the transmit power of the radio frequency (RF) link, This represents the RF link gain between relay R and legitimate user D. The distance from legitimate user D to relay R. This represents the path loss coefficient of the radio frequency (RF) link. The variance of additive white Gaussian noise for legitimate user D. Indicates relay R to non-colluding eavesdroppers RF link gain between Non-conspirator eavesdropper Distance to relay R, Non-conspirator eavesdropper The variance of additive white Gaussian noise.

6. The method according to claim 1, characterized in that, In step 4), the total signal-to-noise ratio of legitimate user D is calculated. The formula is as follows: ， in For the signal-to-noise ratio of a legitimate user D in a visible light communication (VLC) link, The signal-to-noise ratio (SNR) of legitimate user D in the RF link.

7. The method according to claim 1, characterized in that, Calculation in step 5) probability density function of the distribution and cumulative distribution function The formula is as follows: ， ， in , Non-conspirator eavesdropper Distance to relay R, This represents the path loss factor of the radio frequency (RF) link. Non-conspirator eavesdropper The variance of additive white Gaussian noise For the transmit power of the radio frequency (RF) link, Indicates non-conspirator eavesdropper Expected channel power gain.

8. The method according to claim 1, characterized in that, In step 5), the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link is calculated. The implementation steps include the following: 5a) Set up multiple non-colluding eavesdroppers Located on the same radius and with the same link distance to relay R, they are not colluding eavesdroppers. Total signal-to-noise ratio for: ， in , Non-conspirator eavesdropper The signal-to-noise ratio, Non-conspirator eavesdropper The signal-to-noise ratio, Non-conspirator eavesdropper The signal-to-noise ratio, Non-conspirator eavesdropper The signal-to-noise ratio, Non-conspirator eavesdropper The total number; 5b) Total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link eavesdropper for: ， in, The signal-to-noise ratio of relay R in a visible light communication (VLC) link. For the signal-to-noise ratio (SNR) of legitimate users in a visible light communication (VLC) link The maximum value, Non-colluding eavesdroppers on radio frequency (RF) links The overall signal-to-noise ratio.

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