SLIPT-based visible light and radio frequency hybrid system security assessment method

Abstract

The invention discloses a visible light and radio frequency hybrid system security assessment method based on wireless information energy simultaneous transmission SLIPT, and mainly solves the problem that the security assessment of the existing visible light and radio frequency hybrid system is not comprehensive. According to the implementation scheme, a transmitting end sends a visible light signal to a legal user and a relay; the relay separates a direct-current component from the received visible light signal in a wireless information and energy simultaneous transmission mode and transmits the direct-current component to a legal user in a radio-frequency signal mode after energy collection; a plurality of non-collusion eavesdroppers eavesdrop the information of the radio frequency link; according to the signal-to-noise ratio of the legal user and the eavesdropper, calculating the SOP (Secure Outage Probability) and EST (Effective Secure Throughput) of the system; and evaluating the safety performance of the system according to two judgment conditions whether the SOP is less than 1 and the EST is greater than 0 are met at the same time. The system coverage range is expanded by fusing the visible light and the radio frequency system, parameter setting with the best safety can be obtained, the safety performance of the system is improved, and the method can be used for indoor visible light communication system design.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and in particular relates to a visible light VL and radio frequency RF hybrid system security assessment method, which can be used for indoor visible light communication system design. Background Art

[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, fast transmission speed and no electromagnetic interference. Despite this, VLC technology still faces some challenges in practical applications, such as limited coverage area, high dependence on line-of-sight transmission, and easy blocking of communication links. These factors limit its application scope in communication systems. At the same time, although radio frequency (RF) technology is limited by spectrum resources, it has a wider coverage range and stronger penetration, which to some extent makes up for the shortcomings of VLC technology. Therefore, combining the high-speed transmission characteristics of VLC with the wide coverage advantages of RF to build a visible light and radio frequency (VL / RF) hybrid network has become a new trend in the field of communications research, aiming to make full use of the complementary advantages of the two technologies and improve the overall network performance.

[0003] As wireless communication technology has been widely infiltrated into all levels of society, the public's awareness of personal privacy protection and data security has been increasing. VLC and RF are two key technologies in the field of wireless communication. The open nature of their signal propagation has provided convenience for legitimate users, but it has also opened up exploitable loopholes for potential network attackers, which may lead to the leakage of sensitive information and increase network security threats. In order to effectively respond to this challenge, physical layer security (PLS) technology has emerged. Based on the basic principles of information theory, this technology uses the physical properties of wireless channels such as time-varying, randomness, and reciprocity to expand the difference in channel conditions between legitimate communication links and illegal eavesdropping links, providing a new protection mechanism for network security.

[0004] Kumar et al. studied the physical layer security issues in indoor environments where VLC and RF technologies coexist in "PLS analysis in an indoor heterogeneous VLC / RF networkbased on known and unknown CSI". They prevent eavesdropping attacks by imposing positive confidentiality rate restrictions, and evaluate the system security performance based on average confidentiality capacity, connection interruption probability, and security interruption probability. However, since both RF and VLC transmission elements are located at the transmitter and relay transmission is not used in this model, the signal coverage and enhancement capabilities are limited; at the same time, since the model does not use the wireless information energy simultaneous transmission SLIPT technology, the system energy efficiency is low and the anti-interference ability is weak; in addition, since the system only considers the situation where there is a single eavesdropper, it fails to fully consider the complexity and potential security threats brought by multiple eavesdroppers in a high-density user environment, which limits its wide applicability.

[0005] Vats et al. studied the confidentiality performance of a dual-hop hybrid VL / RF system in "Physical layer security for dual-hop VLC / RF communication systems". In this system, the data signal is first sent to the relay R via the RF channel through a single-source antenna in a decoding and forwarding manner. The relay R decodes and converts the received RF signal into an optical signal, which is then sent to the authorized receiving antenna at the destination through the VLC channel. However, in this system, legitimate users only receive the VL signal forwarded by the relay, while eavesdroppers directly intercept the RF signal from the base station. In addition, its design uses the RF base station as the signal source, which is not suitable for the security assessment of indoor VLC systems using light-emitting diodes (LEDs) as signal sources, thus limiting its applicability and effectiveness in modern indoor optical communication environments.

[0006] In their study "Performance Analysis of Hybrid Visible Light / RF Cooperative Communication System Based on SLIPT", Zhang Zhixuan et al. proposed a hybrid VL / RF cooperative communication system based on SLIPT. Based on the existence of a random mobile off-grid relay within the coverage of the light source, the end-to-end link is divided into two parts, the VLC link and the RF communication link, through relay forwarding. However, since the system fails to fully consider the existence of illegal eavesdroppers, it cannot accurately analyze the physical layer security performance of the system. In addition, since the application scenario of the model is limited to the situation where the legitimate user is outside the coverage of the VLC light, it limits its applicability in a wider environment and the comprehensive evaluation of security. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and provide a visible light VL and radio frequency RF hybrid system security assessment method to improve the system safety performance and enhance the system's energy efficiency and anti-interference ability.

[0008] The technical idea to achieve the purpose of the present invention is: by integrating VL and RF communication systems, the coverage of the system is expanded and the signal transmission capability is enhanced, and the interference between cells is effectively reduced, thereby enhancing the anti-interference capability of the system. By using the wireless information energy simultaneous transmission SLIPT technology at the relay, the DC component is separated from the received optical signal and the energy is collected before the RF signal is sent, so as to achieve the synchronous transmission of energy and information, improve the energy efficiency of the system, and then enhance the physical layer security performance of the system.

[0009] According to 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 includes a transmitter S composed of multiple light-emitting diodes LED, a relay R, a legitimate user D equipped with a photodetector PD and an antenna, and multiple non-collusive eavesdroppers E set outside the illumination coverage of the transmitter S k , characterized in that it includes the following steps:

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

[0012] 2) Relay R uses SLIPT to separate the DC component from the received visible light VL signal and collects the energy before sending it to the legitimate user D in the form of RF signal. k Eavesdropping on RF link information;

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

[0014] 4) According to the signal-to-noise ratio γ of the legitimate user D of the VLC link SD and the signal-to-noise ratio γ of the legitimate user D of the RF link RD Calculate the total signal-to-noise ratio γ of legitimate user D D ;

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

[0016] 6) According to the total signal-to-noise ratio γ of the legitimate user D D and the total signal-to-noise ratio of the eavesdropper γ E Calculate the system's safety interruption probability SOP: SOP = Pr{1+γ D ≤T(1+γ E )}, where Pr{·} represents the probability of an event, C th Indicates the system target rate;

[0017] 7) According to the safety interruption probability SOP and the target rate C th , calculate the effective confidentiality throughput EST of the system: EST = C th ×(1-SOP);

[0018] 8) The security performance of the visible light and radio frequency hybrid system is determined based on the two parameters of the security interruption probability SOP and the effective confidentiality throughput EST:

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

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

[0021] 9) The values ​​of the security interruption probability SOP and the effective confidentiality throughput EST of the simulation system under different parameter settings are selected, and the system parameters with the smallest SOP value and the largest EST value are selected as the parameter settings for the optimal security performance of the visible light and RF hybrid system.

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

[0023] First, the present invention integrates visible light VL and radio frequency RF communication systems, fully utilizes the respective advantages of visible light communication VLC and radio frequency RF communication, realizes highly complementary and optimized configuration of resources, and can not only expand the coverage of the system, but also significantly enhance the signal transmission capability, effectively reduce the interference between cells, and thus enhance the anti-interference ability of the system;

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

[0025] Third, by simulating the scenario of multiple eavesdroppers eavesdropping at the same time, the present invention can not only enhance the real adaptability of the system design, but also significantly improve the system's ability to cope with complex security threats, making the system design more in line with the needs of actual applications and diversified scenarios, thereby enhancing the practicality and adaptability of the system;

[0026] Fourthly, the present invention can obtain the parameter setting with the best security performance by simulating the values ​​of system security interruption probability SOP and effective confidentiality throughput EST under different system parameter settings when there are multiple non-collusive eavesdroppers, and comparing and selecting them. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0028] Figure 1 It is a flow chart for realizing the present invention;

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

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

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

[0032] Figure 5To simulate the system security interruption probability SOP under different legal user activity range radius L with the transmission power P of a single light emitting diode LED, LED Change curve chart;

[0033] Figure 6 To simulate the effective confidentiality throughput EST of the system under different legal user activity range radius L with the target rate C th Change curve chart;

[0034] Figure 7 To simulate the system safety interruption probability SOP under different photoelectric conversion coefficients ρ of the photoelectric detector PD with the emission power P of a single light emitting diode LED, LED Change curve chart;

[0035] Figure 8 To simulate the effective confidentiality throughput EST of the system under different photoelectric detector PD photoelectric conversion coefficients ρ of the present invention with the change of target rate C th Change curve chart;

[0036] Fig. 9 To simulate the system safety interruption probability SOP under different light emitting diode numbers N and the transmission power P of a single light emitting diode LED, LED Change curve chart;

[0037] Fig.10 To simulate the effective confidentiality throughput EST of the system with different numbers of light-emitting diodes N and target rate C th Change curve graph. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clear, they are further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0039] Reference Figure 1 This example is based on the SLIPT visible light and radio frequency hybrid system security assessment method, and its implementation steps are as follows:

[0040] Step 1: Build a SLIPT-based visible light and RF hybrid system.

[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-collusive eavesdroppers E. k , where the transmitter S consists of N light-emitting diodes LED, the legitimate user D is equipped with a photodetector PD and an antenna, and multiple non-collusive eavesdroppers E k They are all outside the illumination coverage of the transmitter S.

[0042] Figure 2 The model diagram of the visible light and radio frequency hybrid system based on wireless information energy simultaneous transmission SLIPT in this example, where d SD represents the distance from the transmitter S to the legitimate user D, d D represents the distance from the legitimate user D to the relay R, L represents the radius of the legitimate user D's active range, L1 is the radius of the light coverage range of the transmitter S, H is the distance from the transmitter S to the relay R, d E,k For non-colluding eavesdropper E k The distance to the relay R.

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

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

[0045] The legal user D and the relay R receive the visible light VL signal, generating a visible light communication VLC link SD between the transmitter and the legal 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 in the SD link SD :

[0048]

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

[0050] 3.2) Calculate the channel gain h between the transmitter S and the relay R in 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 the legitimate user D in the visible light communication VLC link SD SD .

[0054] According to 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 the 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 LED at the transmitting end S, and P LED represents the emitted optical power of a single LED, A represents the peak amplitude of the modulated power signal, and h SD is the channel gain between the transmitter S and the legitimate user D, and N0 represents the noise power of the legitimate user D.

[0057] Step 5: The relay collects energy to generate RF links RD and RE and visible light-RF hybrid link SRE, and calculates the received optical signal y of the legitimate user D of the RD link respectively. RD and RE link multiple non-colluding eavesdroppers E k The received optical signal y RE,k .

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

[0059] 5.2) According to the separated 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 is the open circuit voltage of the photodetector PD, T1 is the duration of the transmitter S sending the visible light VL signal to the relay R, and T2 represents the duration of the relay R transmitting the data to the receiver;

[0062] 5.3) Relay R collects energy E R , with the transmission power P RSend RF signal to legitimate user D, where P R =E R / T2;

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

[0064] 5.5) According to the transmission power P of relay R R , calculate the received optical signal y of the legitimate user D on the RF link RD RD :

[0065]

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

[0067] 5.6) According to the transmission power P of relay R R , calculate the number of non-colluding eavesdroppers E on the RF link RE k The received optical signal y RE,k :

[0068]

[0069] where d E,k For non-colluding eavesdropper E k Distance to relay R, h RE,k Represents relay R to non-colluding eavesdropper E k The RF link gain between them, n2 represents the 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 the legitimate user D in the RF link RD RD and multiple non-colluding eavesdroppers E on the RF link RE k The signal-to-noise ratio γ RE,k And the total signal-to-noise ratio γ of the legitimate user D in the two links D .

[0071] 6.1) According to the received optical signal y of the legitimate user D on the RF link RD RD , calculate the signal-to-noise ratio γ of the legitimate user D in the RF link RDRD :

[0072]

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

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

[0075]

[0076] where h RE,k Represents relay R to non-colluding eavesdropper E k The RF link gain between E,k For non-colluding eavesdropper E k The distance to relay R, N2 is the distance to non-colluding eavesdropper E k Variance of additive white Gaussian noise;

[0077] 6.3) According to the signal-to-noise ratio γ of the legitimate user D in the visible light communication VLC link SD SD and the signal-to-noise ratio γ of the legitimate user D in the RF link RD RD , calculate the total signal-to-noise ratio γ of the legitimate user D in the two links D :

[0078] γ D =γ SD +γ RD .

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

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

[0081]

[0082] where d E,k For non-colluding eavesdropper E k The distance to the relay R, η is the path loss coefficient of the RF link, and N2 is the non-collusive eavesdropper E k Variance of additive white Gaussian noise, P R is the transmission power of the radio frequency RF link;

[0083] 7.2) Calculate |h RE,k 2 About Gamma RE,k The derivative of :

[0084]

[0085] 7.3) According to the characteristics of the RF link RE that it obeys independent Rayleigh fading, calculate the relay R to the non-collusive eavesdropper E k The RF link gain h RE,k Square|h RE,k 2 The probability density function of is:

[0086]

[0087] where g RE,k h is the square of the RF RE link channel gain RE,k 2 expectations;

[0088] 7.4) According to |h RE,k 2 The probability density function of and |h RE,k 2 About Gamma 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 the non-colluding eavesdropper E k Signal-to-noise ratio RE,k The probability density function f γ (γ RE,k ), calculate γRE,k The cumulative distribution function F γ (γ RE,k ):

[0091]

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

[0093] 8.1) Set up multiple non-collusive eavesdroppers E k Located on the same radius, and with the same link distance to the relay R, calculate the number of non-collusive eavesdroppers E on the RF link. k The 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 is the signal-to-noise ratio of the non-colluding eavesdropper E1, γ RE,2 is the signal-to-noise ratio of the non-colluding eavesdropper E2, γ RE,k For non-colluding eavesdropper E k The signal-to-noise ratio, γ RE,M For non-colluding eavesdropper E M The signal-to-noise ratio of M is the non-collusive eavesdropper E k The total number of

[0096] 8.2) According to the signal-to-noise ratio γ of the visible light communication VLC link relay R SR and RF link non-colluding eavesdropper E k The 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] Among them, γ SR =V max , V max is the signal-to-noise ratio γ of the legitimate user D in the visible light communication VLC link SD The maximum value of .

[0099] Step 9: According to the total signal-to-noise ratio γ of the legitimate user D D and the total signal-to-noise ratio of the eavesdropper γ ECalculate the system's safe outage probability SOP.

[0100] 9.1) The existing definition of safety interruption probability SOP = Pr{1+γ D ≤T(1+γ E )} is further converted into the following formula:

[0101]

[0102] Where Pr{·} represents the probability of an event, C th represents the system target rate, γ D is the total signal-to-noise ratio of legitimate user D, γ E is the total signal-to-noise ratio of the eavesdropper in the transmitter-relay-eavesdropper SRE link;

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

[0104]

[0105] in All are intermediate variables; V min 、V max are the signal-to-noise ratio γ of the legitimate user D in the visible light communication VLC link SD The minimum and maximum values ​​of d D is the distance from the legitimate user D to the relay R, η represents the path loss coefficient of the RF link, N1 is the variance of the additive Gaussian white noise of the legitimate user D, P R is the transmission power of the RF link, L represents the radius of the range in which the legal user D can move, m represents the Lambertian transmission 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 light-emitting diodes LED at the transmitter S, P LED represents the emitted optical power of a single LED, A represents the peak amplitude of the modulated power signal, N0 represents the noise power of the legitimate user D, and A r represents the effective emission area of ​​the photodetector PD, T 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) According to the total signal-to-noise ratio γ of the transmitter-relay-eavesdropper SRE link E , calculate its cumulative distribution function F γ (γ E ):

[0107]

[0108] in d E,k For non-colluding eavesdropper E k The distance to relay R, N2 is the distance to non-colluding eavesdropper E k Variance of additive Gaussian white noise, g RE,k represents the non-collusive eavesdropper E k The expectation of the channel power gain, M is the non-colluding eavesdropper E k The total number of

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

[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 ) and the cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link obtained in step 9.4) Solving the probability problem Transformed into the following process of solving the integral:

[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, calculating the effective confidentiality throughput EST of the system, and judging the security performance of the hybrid system of visible light and radio frequency according to the parameter EST and the security interruption probability SOP.

[0116] 10.1) According to the safety interruption probability SOP and the target rate C set by the system th Calculate the effective confidentiality throughput EST of the system:

[0117] EST=C th ×(1-SOP);

[0118] 10.2) Set the judgment thresholds of security interruption probability SOP and effective confidentiality throughput EST to 1 and 0 respectively, and make a preliminary judgment on their security performance:

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

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

[0121] 10.3) Simulate the values ​​of the security interruption probability SOP and effective confidentiality throughput EST of the system under different parameter settings, and select the system parameters with the smallest SOP value and the largest EST value as the parameter settings for the optimal security performance of the visible light and RF hybrid system.

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

[0123] 1. Simulation conditions

[0124] Condition 1. The transmitting power P of a single light-emitting diode LED at the transmitting end S LED Set to 0.1-0.7W, the number of non-collusive 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 speed C th Set to 0-10, the number of non-collusive 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. Transmitting power P of a single light-emitting diode LED at the transmitting end S LED Set to 0.1-0.7W, the number of non-collusive 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-collusive 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. Transmitting power P of a single light-emitting diode LED at the transmitting end S LED It is set to 0.1-0.7W, the number of non-collusive 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 speed C thSet to 0-10, the number of non-collusive 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. Transmitting power P of a single light-emitting diode LED at the transmitting end S LED Set to 0.1-0.7W, the number of non-collusive eavesdroppers is M=1, M=3, M=5, and the number of LEDs is N=13, N=15, N=17;

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

[0132] 2. Simulation content and results

[0133] Simulation 1, simulating the system security interruption probability SOP under the parameter setting of condition 1, that is, 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 Changes, such as Figure 3 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 , as P LED As the number of non-collusive eavesdroppers M increases, the SOP of the system gradually decreases, and the system security performance improves. 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-collusive eavesdroppers M increases, the SOP value increases and the system security performance deteriorates.

[0135] Simulation 2, under the parameter setting of condition 2, the system effective confidentiality throughput EST is simulated, and the results are as follows Figure 4 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, the system EST first reaches a peak value and then gradually decreases, and the system security performance first improves and then deteriorates; as the number of eavesdroppers M increases, the system EST decreases and the system security performance deteriorates; when the number of non-collusive eavesdroppers M is the same, for the same C th , with d E As the value of EST increases, the safety performance of the system improves.

[0137] Simulation 3, under the parameter setting of condition 3, the system safety interruption probability SOP is simulated, and the results are as follows Figure 5 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 value of the system SOP increases, it gradually decreases, and the system security performance becomes better; when the number of non-collusive 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 becomes better; ,as the number of non-collusive eavesdroppers M increases, the SOP value increases and the system security performance deteriorates.

[0139] Simulation 4, under the parameter setting of condition 4, the system effective confidentiality throughput EST is simulated, and the results are as follows Figure 6 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-collusive 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-collusive eavesdroppers M increases, the EST value decreases and the system security performance deteriorates.

[0141] Simulation 5, under the parameter setting of condition 5, the system safety interruption probability SOP is simulated, and the results are as follows Figure 7 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, which can bring higher system security. When the number of non-collusive eavesdroppers M is the same, for the same P LED ,As ρ increases, the system SOP value decreases, and the system security performance becomes better; as the number of non-collusive eavesdroppers M increases, the SOP value increases, and the system security performance becomes worse.

[0143] Simulation 6, under the parameter setting of condition 6, the system effective confidentiality throughput EST is simulated, and the results are as follows Figure 8 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-collusive 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-collusive eavesdroppers M increases, the EST value decreases and the system security performance deteriorates.

[0145] Simulation 7, under the parameter setting of condition 7, the system safety interruption probability SOP is simulated, and the results are as follows Fig. 9 shown.

[0146] from Fig. 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, which can bring higher system security. When the number of non-collusive eavesdroppers M is the same, for the same P LED ,As N increases, the system SOP value decreases and the system security performance becomes better; ,as the number of non-collusive eavesdroppers M increases, the SOP value increases and the system security performance becomes worse.

[0147] Simulation 8, under the parameter setting of condition 8, the system effective confidentiality throughput EST is simulated, and the results are as follows Fig.10 shown.

[0148] from Fig.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-collusive 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 becomes better; ,as the number of non-collusive eavesdroppers M increases, the EST value decreases and the system security performance becomes worse.

[0149] The above simulation results show that the SLIPT-based visible light and RF hybrid system security assessment method proposed in the present invention expands the scope of comprehensive security assessment in existing research and provides a new physical layer security enhancement solution for visible light and RF hybrid systems.

[0150] The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principles of the present invention, they may make various modifications and changes in form and details without departing from the principles and structures 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 the present invention are only for a clear description of the implementation scheme of the present invention to facilitate understanding, and the order of the step numbers is not limited.

Claims

1. A security assessment method for a visible light and radio frequency hybrid system based on SLIPT, the system includes a transmitter S composed of multiple light-emitting diodes LED, a relay R, a legitimate user D equipped with a photodetector PD and an antenna, and multiple non-collusive eavesdroppers E set outside the illumination coverage of the transmitter S k ,characterized in that, The steps include: 1) The transmitter S sends a visible light VL signal to the legitimate user D and the relay R, and calculates the channel gain h between the transmitter S and the legitimate user D in the visible light communication VLC link. SD The channel gain h between the relay R SR , and according to h SD Calculate the signal-to-noise ratio γ of the legitimate user D of the VLC link SD ; 2) Relay R uses SLIPT to separate the DC component from the received visible light VL signal and collects the energy before sending it to the legitimate user D in the form of RF signal. k Eavesdropping on RF link information; 3) Calculate the received optical signal y of the legitimate user D in the RF link RD and multiple non-colluding eavesdroppers E k The received optical signal y RE,k , and calculate the signal-to-noise ratio γ of the legitimate user D of the RF link RD and multiple non-colluding eavesdroppers E k The signal-to-noise ratio γ RE,k ; 4) According to the signal-to-noise ratio γ of the legitimate user D of the VLC link SD and the signal-to-noise ratio γ of the legitimate user D of the RF link RD Calculate the total signal-to-noise ratio γ of legitimate user D D ; 5) According to the non-colluding eavesdropper E k Signal-to-noise ratio RE,k Calculate the probability density function f of its distribution γ (γ RE,k ) and the cumulative distribution function F γ (γ RE,k ), and calculate the total signal-to-noise ratio γ of the transmitter-relay-eavesdropper SRE link E ; 6) According to the total signal-to-noise ratio γ of the legitimate user D D and the total signal-to-noise ratio of the eavesdropper γ E Calculate the system's safety interruption probability SOP: SOP = Pr{1+γ D ≤T(1+γ E )}, where Pr{·} represents the probability of an event, C th Indicates the system target rate; 7) According to the safety interruption probability SOP and the target rate C th , calculate the effective confidentiality throughput EST of the system: EST = C th ×(1-SOP); 8) The security performance of the visible light and radio frequency hybrid system is determined based on the two parameters of the security interruption probability SOP and the effective confidentiality throughput EST: If the SOP value is less than 1 and the EST value is greater than 0, the system is safe; If any one of the conditions is not met, the system is unsafe. 9) The values ​​of the security interruption probability SOP and the effective confidentiality throughput EST of the simulation system under different parameter settings are selected, and the system parameters with the smallest SOP value and the largest EST value are selected as the parameter settings for the optimal security performance of the visible light and RF hybrid system.

2. The method according to claim 1, characterized in that In step 1), the channel gain h between the transmitter S and the legitimate user D is calculated. SD The channel gain h between the relay R SR , the formula is as follows: Where m represents the Lambertian emission coefficient, A r represents the effective emission area of ​​the photodetector PD, d SD represents the distance from the transmitter S to the legitimate user D, is the radiation angle of the transmitter S, ψ is the incident angle of the photodetector PD at the legitimate user D, T s (ψ) is the gain of the optical filter in the photodetector PD, g(ψ) is the gain of the concentrator in the photodetector PD, and H represents the distance from the transmitter S to the relay R.

3. The method according to claim 1, characterized in that In step 1), the signal-to-noise ratio γ of the legitimate user D of the VLC link is calculated SD , the formula is as follows: Where ρ represents the photoelectric conversion efficiency of the photodetector PD, N represents the total number of light-emitting diodes LED at the transmitting end S, and P LED represents the emitted optical power of a single LED, A represents the peak amplitude of the modulated power signal, and h SD is the channel gain between the transmitter S and the legitimate user D, and N0 represents the noise power of the legitimate user D.

4. The method according to claim 1, characterized in that: In step 3), the received optical signal y of the legitimate user D is calculated RD , the implementation steps include the following: 3a) Relay R uses wireless information energy simultaneous transmission SLIPT to separate the DC component from the received photocurrent and collect energy to obtain the collected energy E R : E R =fy dc V oc (T1+T2), Where f is the filling factor, y dc (t) represents the DC part of the signal, V oc is the open circuit voltage of the photodetector PD; T1 represents the duration of the first time slot, during which the transmitter S sends a visible light VL signal to the relay R; T2 represents the duration of the second time slot, during which the relay R uses the collected energy to transmit data to the receiver through the radio frequency RF link; 3b) According to the energy E collected by relay R R , calculate the transmission power of the RF link: P R =E R / T2; 3c) According to the transmission power P R , calculate the optical signal y received by the legitimate user D RD : where d D is the distance from the legitimate user D to the relay R, η represents the path loss coefficient of the RF link, h 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 Gaussian white noise with a mean of 0 and a variance of N1.

5. The method according to claim 1, characterized in that In step 3), calculate multiple non-collusive eavesdroppers E k The received optical signal y RE,k , the formula is as follows: Where P R is the transmission power of the RF link, d E,k For non-colluding eavesdropper E k The distance to the relay R, η is the path loss coefficient of the RF link, h RE,k Represents relay R to non-colluding eavesdropper E k where s is the transmission signal of relay R, and n2 represents the additive white Gaussian noise with a mean of 0 and a variance of N2.

6. The method according to claim 1, characterized in that In step 3), the signal-to-noise ratio γ of the legitimate user D of the RF link is calculated RD and multiple non-colluding eavesdroppers E k The signal-to-noise ratio γ RE,k , the formula is as follows: Where P R is the transmission power of the RF link, h RD represents the RF link gain between relay R and legitimate user D, d D is the distance from the legitimate user D to the relay R, η represents the path loss coefficient of the RF link, N1 is the additive Gaussian white noise variance of the legitimate user D, h RE,k Represents relay R to non-colluding eavesdropper E k The RF link gain between E,k For non-colluding eavesdropper E k The distance to relay R, N2 is the distance to non-colluding eavesdropper E k Variance of additive white Gaussian noise.

7. The method according to claim 1, characterized in that In step 4), the total signal-to-noise ratio γ of the legitimate user D is calculated D , the formula is as follows: c D =c SD +g RD , where γ SD is the signal-to-noise ratio of the legitimate user D in the visible light communication VLC link, γ RD is the signal-to-noise ratio of the legitimate user D in the RF link.

8. The method according to claim 1, characterized in that: Calculate γ in step 5) RE,k The probability density function f of the distribution γ (γ RE,k ) and the cumulative distribution function F γ (γ RE,k ), the formula is as follows: in d E,k For non-colluding eavesdropper E k The distance to the relay R, η is the path loss coefficient of the RF link, and N2 is the non-collusive eavesdropper E k Variance of additive white Gaussian noise, P R is the transmission power of the RF link, g RE,k represents the non-collusive eavesdropper E k Expected channel power gain.

9. The method according to claim 1, characterized in that: In step 5), the total signal-to-noise ratio γ of the transmitter-relay-eavesdropper SRE link is calculated. E , the implementation steps include the following: 5a) Set up multiple non-collusive eavesdroppers E k Located on the same radius and with the same link distance to relay R, non-collusive eavesdropper E k The total signal-to-noise ratio γ RE for: c RE =max{γ RE,1 ,c RE,2 ,…,c RE,k ,…,c RE,M } where k∈{1,2,…,M},γ RE,1 is the signal-to-noise ratio of the non-colluding eavesdropper E1, γ RE,2 is the signal-to-noise ratio of the non-colluding eavesdropper E2, γ RE,k For non-colluding eavesdropper E k The signal-to-noise ratio, γ RE,M For non-colluding eavesdropper E M The signal-to-noise ratio of M is the non-collusive eavesdropper E k The total number of 5b) The total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link γ E for: c E =min{γ SR ,c RE }, Among them, γ SR =V max is the signal-to-noise ratio of the visible light communication VLC link relay R, V max is the signal-to-noise ratio γ of the legitimate user D in the visible light communication VLC link SD The maximum value of γ RE For non-colluding eavesdroppers E on the RF link k The overall signal-to-noise ratio.

10. The method according to claim 1, characterized in that Step 6) calculates the system's safety interruption probability SOP = Pr{1+γ D ≤T(1+γ E )} is the process of converting the probability problem into the integral problem, and its implementation steps include the following: 6a) Set the safety interruption probability SOP = Pr{1+γ D ≤T(1+γ E )} is further converted into the following formula: Where Pr{·} represents the probability of an event, C th represents the system target rate, γ D is the total signal-to-noise ratio of legitimate user D, γ E is the total signal-to-noise ratio of the eavesdropper in the transmitter-relay-eavesdropper SRE link; 6b) According to the total signal-to-noise ratio γ of the legitimate user D D , calculate its probability density function f γ (γ D ): in b=c-1, V min 、V max are the signal-to-noise ratio γ of the legitimate user D in the visible light communication VLC link SD The minimum and maximum values ​​of d D is the distance from the legitimate user D to the relay R, η represents the path loss coefficient of the RF link, N1 is the variance of the additive Gaussian white noise of the legitimate user D, P R is the transmission power of the RF link, L represents the radius of the range in which the legal user D can move, m represents the Lambertian transmission 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 light-emitting diodes LED at the transmitter S, P LED represents the emitted optical power of a single LED, A represents the peak amplitude of the modulated power signal, N0 represents the noise power of the legitimate user D, and A r represents the effective emission area of ​​the photodetector PD, T 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; 6c) According to the total signal-to-noise ratio γ of the transmitter-relay-eavesdropper SRE link E , calculate its cumulative distribution function F γ (γ E ): in d E,k For non-colluding eavesdropper E k The distance to relay R, N2 is the distance to non-colluding eavesdropper E k Variance of additive Gaussian white noise, g RE,k represents the non-collusive eavesdropper E k The expectation of the channel power gain, M is the non-colluding eavesdropper E k The total number of 6d) Calculate γ E Pick The cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link is 6e) Using the probability density function f of the total signal-to-noise ratio of the legitimate user D obtained in step 6b) γ (γ D ) and the cumulative distribution function of the total signal-to-noise ratio of the transmitter-relay-eavesdropper SRE link obtained in step 6d). Solving the probability problem Transformed into the following process of solving the integral: 6f) Substitute the result of step 6e) into step 6a) to calculate the system safety interruption probability SOP:

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