Power Line Adaptive Relay Cooperative Physical Layer Security Transmission Method

Abstract

A power line adaptive relay cooperation physical layer security transmission method belongs to the field of power line carrier security communication. The present invention solves the contradiction between the spectrum efficiency loss of the existing power line relay cooperation physical layer security transmission method in half-duplex and the self-interference problem in full-duplex, as well as the problem of how to ensure the secure transmission of the system when the main channel and the eavesdropping channel are correlated. The present invention proposes a relay cooperation interference physical layer security transmission scheme based on half-duplex and full-duplex for the correlation between the main channel and the eavesdropping channel, which can ensure the secure transmission of the system when the channel correlation is enhanced; and finds a balance between the spectrum efficiency loss of half-duplex and the self-interference problem of full-duplex, and proposes an adaptive relay cooperation security transmission mechanism. This mechanism calculates the average security capacity of the full-duplex / half-duplex mode respectively, and selects the duplex mode with the goal of maximizing the average security capacity. The present invention is mainly applied in power line carrier communication.

Description

Technical Field

[0001] The present invention belongs to the field of power line carrier secure communication. Background Art

[0002] Power line carrier communication (PLC) technology uses existing power lines as communication media for data transmission. It has the advantages of low cost and wide coverage, can truly realize the organic integration of power flow and information flow, is one of the important communication methods in smart grids, and is also an effective technical guarantee for building a ubiquitous power Internet of Things. It is widely used in remote automatic meter reading, intelligent distribution substations, smart street lights, smart homes, security and fire alarm systems, etc. However, the power line itself is designed for energy transmission. There are not only line losses related to transmission distance and operating frequency in the channel, but also multipath effects caused by impedance mismatch, and high-amplitude pulse noise introduced by load switching, which severely restricts the long-distance reliable transmission of signals. At the same time, the rapid expansion of power grid big data services requires that the communication network can provide larger-scale terminal access, higher communication rates, and larger system capacities. And with the continuous deepening of the integration of information systems and energy systems, the information security issues of the power Internet of Things have gradually emerged. Due to the broadcast nature of the channel, PLC is extremely vulnerable to eavesdropping attacks. The relay cooperation physical layer security (PLS) transmission technology based on the physical characteristics of the channel is an effective means to solve the above problems. The problems currently faced by the PLC relay cooperation physical layer security transmission technology are as follows:

[0003] (1) The contradiction between the spectrum efficiency loss of half-duplex (HD) and the residual self-interference (RSI) of full-duplex (FD). Although FD relays have higher spectrum efficiency, their performance is limited by the size of RSI, and their performance is not necessarily better than that of HD relays;

[0004] (2) Existing relay cooperation physical layer security transmission schemes usually assume that the eavesdropping channel state information (CSI) is known or use technical means such as beamforming and artificial noise based on the independence of the channel to deteriorate the quality of the eavesdropping channel without affecting the quality of the main channel. In actual applications, since eavesdropping nodes are mostly passive eavesdropping, it is difficult to obtain the real-time CSI of the eavesdropping channel, and there may be correlations between PLC channels. The performance of the physical layer security transmission scheme based on channel independence will be reduced. Therefore, the above two problems need to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to solve the contradiction between the spectrum efficiency loss of half-duplex (HD) and the self-interference problem of full-duplex (FD) in the existing power line relay cooperation physical layer security transmission method, and the problem of how to ensure the secure transmission of the system when the main channel and the eavesdropping channel are correlated. The present invention provides a power line adaptive relay cooperation physical layer security transmission method.

[0006] Power line adaptive relay cooperative physical layer secure transmission method, which is implemented based on a PLC relay communication system. The PLC relay communication system includes a transmitting end node A, a receiving end node B, a relay node R, and an eavesdropping node E. The eavesdropping node E is used to steal information on the communication link between the relay node R and the receiving end node B. The method includes the following steps:

[0007] S1. The transmitting end node A sends a pilot signal to the relay node R, and combining with the pulse noise suppression and channel estimation method, the relay node R estimates the channel instantaneous gain h AR ;

[0008] h AR is the channel instantaneous gain from the transmitting end node A to the relay node R;

[0009] S2. Determine whether the channel of the PLC relay communication system is symmetric. If the determination result is yes, execute step S3; if the determination result is no, execute step S4;

[0010] S3. The receiving end node B sends a pilot signal to the relay node R, and combining with the pulse noise suppression and channel estimation method, the relay node R estimates the channel instantaneous gain h BR , and execute step S6; where, h BR =h RB ;

[0011] h BR is the channel instantaneous gain from the receiving end node B to the relay node R;

[0012] h RB is the channel instantaneous gain from the relay node R to the receiving end node B;

[0013] S4. The relay node R sends a pilot signal to the receiving end node B, and combining with the pulse noise suppression and channel estimation method, the receiving end node B estimates the channel instantaneous gain h RB , and execute step S5;

[0014] h RB is the channel instantaneous gain from the relay node R to the receiving end node B;

[0015] S5. The receiving end node B sends the channel instantaneous gain h RB and the pilot signal to the relay node R. The relay node R receives the channel instantaneous gain h RB and the pilot signal. At the same time, the relay node R estimates the channel instantaneous gain h BR according to the received pilot signal by using the pulse noise suppression and channel estimation method, and execute step S6;

[0016] h BR is the channel instantaneous gain from the receiving end node B to the relay node R;

[0017] S6. The relay node R calculates the average secure capacity in the full-duplex mode and the average secure capacity in the half-duplex mode

[0018]

[0019] S7. The relay node R judges and the magnitudes of, if then it is determined that the relay node R and the receiving end node B adopt the full-duplex mode, and step S8 is executed; otherwise, it is determined that the relay node R and the receiving end node B adopt the half-duplex mode, and step S9 is executed;

[0020] S8. The relay node R sends a broadcast to notify the transmitting end node A and the receiving end node B that the relay node R and the receiving end node B adopt the full-duplex mode. At the same time, it also sends a broadcast to notify the receiving end node B of the channel instantaneous gain h BR to complete the configuration of the PLC relay communication system, and step S10 is executed;

[0021] S9. The relay node R sends a broadcast to notify the transmitting end node A and the receiving end node B that the relay node R and the receiving end node B adopt the half-duplex mode. At the same time, it also sends a broadcast to notify the receiving end node B of the channel instantaneous gain h BR to complete the configuration of the PLC relay communication system, and step S11 is executed;

[0022] S10. In each time slot, the transmitting end node A sends a confidential signal to the relay node R. At the same time, the receiving end node B sends an artificial interference signal to the relay node R; in the current time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal in the previous time slot to the receiving end node B, and the receiving end node B uses the channel instantaneous gain h BR and the channel instantaneous gain h RB to demodulate the received mixed signal, so as to realize the secure transmission of the confidential signal;

[0023] S11. In the current time slot, the transmitting end node A sends a confidential signal to the relay node R. At the same time, the receiving end node B sends an artificial interference signal to the relay node R; in the next time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal to the receiving end node B, and the receiving end node B uses the channel instantaneous gain h BR and the channel instantaneous gain h RB to demodulate the received mixed signal, so as to realize the secure transmission of the confidential signal.

[0024] Preferably, in step S6, the relay node R calculates the average secure capacity of the full-duplex mode according to the received signal-to-noise ratio at the receiving end node B, the statistical parameters of the eavesdropping channel gain, and the statistical parameters of the interference channel gain in the full-duplex mode. Meanwhile, the relay node R also calculates the average secure capacity of the half-duplex mode according to the received signal-to-noise ratio at the receiving end node B and the statistical parameters of the eavesdropping channel gain in the half-duplex mode.

[0025] The statistical parameters of the eavesdropping channel gain include μ RE and where μ RE is the mean of the natural logarithm of the eavesdropping channel gain, is the variance of the natural logarithm of the eavesdropping channel gain; the statistical parameters of the interference channel gain include μ BE and where μ BE is the mean of the natural logarithm of the interference channel gain, is the variance of the natural logarithm of the interference channel gain;

[0026] The eavesdropping channel is the channel between the relay node R and the eavesdropping node E; the interference channel is the channel between the receiving end node B and the eavesdropping node E.

[0027] Preferably, in step S6, the relay node R calculates the average secure capacity of the full-duplex mode The implementation method includes:

[0028] S611. Calculate the average capacity of the main channel in the full-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the full-duplex mode where the main channel is composed of the channel between the transmitting end node A and the relay node R and the channel between the relay node R and the receiving end node B;

[0029] S612. Calculate the average capacity of the eavesdropping channel in the full-duplex mode according to the statistical parameters of the eavesdropping channel gain and the statistical parameters of the interference channel gain in the full-duplex mode

[0030] S613. Calculate the average secure capacity of the full-duplex mode according to and

[0031] Preferably, in step S611,

[0032] The

[0033] where P A ​is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the occurrence state of impulse noise in the channel noise at the relay node R; when S R = 0, represents the probability that no impulse noise occurs at the relay node R; S R = 1, represents the probability that impulse noise occurs at the relay node R; S B is the occurrence state of impulse noise in the channel noise at the receiving end node B; S B = 0, represents the probability that no impulse noise occurs at the receiving end node B; S B = 1, represents the probability that impulse noise occurs at the receiving end node B; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R, is the total noise power of the receiving end node B, and is the RSI noise power of the receiving end node B, is the channel noise power of the receiving end node B, G FD is the gain coefficient of the relay node R in the amplify-and-forward protocol in the full-duplex mode.

[0034] Preferably, in step S612, calculating the average capacity of the wiretap channel in the full-duplex mode is implemented as follows:

[0035] S612-1. According to the statistical parameters of the wiretap channel gain and the statistical parameters of the interference channel gain in the full-duplex mode, calculate the first probability density function f of x1 and x2 JP,LN (x1, x2), specifically:

[0036]

[0037] where x1 is a variable that follows a Log-N distribution with a mean of 2μ RE and a variance of x2 is a variable that follows a Log-N distribution with a mean of 2μ BE and a variance of σ RE is the standard deviation of the natural logarithm of the wiretap channel gain, σ BE is the standard deviation of the natural logarithm of the interference channel gain, ρ RE,BEis the correlation coefficient of the natural logarithm of the eavesdropping channel gain and the natural logarithm of the interference channel gain;

[0038] S612-2. According to the first probability density function f JP,LN (x1,x2), obtain the average capacity of the eavesdropping channel in the full-duplex mode Specifically:

[0039]

[0040] The

[0041] where P A is the transmission power of the transmitting node A, P B is the transmission power of the receiving node B, P R is the transmission power of the relay node R, S R is the pulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no pulse noise occurs at the relay node R; S R = 1, represents the probability that pulse noise occurs at the relay node R; S E is the pulse noise occurrence state in the channel noise at the eavesdropping node E; S E = 0, represents the probability that no pulse noise occurs at the eavesdropping node E; S E = 1, represents the probability that pulse noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R.

[0042] Preferably, in step S613, according to and calculate the average security capacity of the full-duplex mode The implementation method is:

[0043] where represents taking the maximum value between 0 and both.

[0044] Preferably, in step S6, the relay node R calculates the average security capacity of the half-duplex mode, and the implementation method includes:

[0045] S621. Calculate the average capacity of the main channel in the half-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the half-duplex mode wherein the main channel is composed of the channel between the transmitting end node A and the relay node R and the channel between the relay node R and the receiving end node B;

[0046] S622. Calculate the average capacity of the eavesdropping channel in the half-duplex mode according to the statistical parameters of the eavesdropping channel gain in the half-duplex mode

[0047] S623. Calculate the average secure capacity of the half-duplex mode according to and

[0048] Preferably, in step S621,

[0049] the and

[0050] where P A is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the pulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no pulse noise occurs at the relay node R; when S R = 1, represents the probability that pulse noise occurs at the relay node R; S B is the pulse noise occurrence state in the channel noise at the receiving end node B; when S B = 0, represents the probability that no pulse noise occurs at the receiving end node B; when S B = 1, represents the probability that pulse noise occurs at the receiving end node B; is the channel noise power of the relay node R, is the channel noise power of the receiving end node B, and G HD is the gain coefficient of the relay node R in the amplify-and-forward protocol in the half-duplex mode.

[0051] Preferably, in step S622, the implementation manner of calculating the average capacity of the eavesdropping channel in the half-duplex mode includes:

[0052] ​​S622-1. Calculate the second probability density function \(f\) of \(x1\) according to the statistical parameters of the eavesdropping channel gain in the half-duplex mode, specifically: LN (x1), specifically:

[0053]

[0054] where \(x1\) is a variable that conforms to the Log-N distribution with a mean of \(2\mu\) RE and a variance of , and \(\sigma\) RE is the standard deviation of the natural logarithm of the eavesdropping channel gain;

[0055] S622-2. Calculate the average capacity of the eavesdropping channel in the half-duplex mode according to the second probability density function \(f\) LN (x1), specifically: Specifically:

[0056]

[0057] The

[0058] where \(P\) A is the transmission power of the transmitting end node A, \(P\) B is the transmission power of the receiving end node B, \(P\) R is the transmission power of the relay node R, \(S\) R is the state of impulse noise occurrence in the channel noise at the relay node R; when \(S\) R = 0, represents the probability that no impulse noise occurs at the relay node R; when \(S\) R = 1, represents the probability that impulse noise occurs at the relay node R; when \(S\) E is the state of impulse noise occurrence in the channel noise at the eavesdropping node E; when \(S\) E = 0, represents the probability that no impulse noise occurs at the eavesdropping node E; when \(S\) E = 1, represents the probability that impulse noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the channel noise power of the relay node R.

[0059] Preferably, in step S623, according to and calculate the average secure capacity of the half-duplex mode, and the implementation method is:

[0060] where, Indicates taking the maximum value between 0 and the two.

[0061] Principle analysis:

[0062] Although the full-duplex (FD) mode has higher spectral efficiency, its performance is limited by RSI. Therefore, the performance of the FD system is not necessarily better than that of the HD system. To find a balance between the spectral efficiency loss of the half-duplex (HD) and the self-interference problem of the FD, an adaptive relay cooperative secure transmission mechanism is proposed. This mechanism calculates the average secure capacity of the full-duplex / half-duplex (FD / HD) mode respectively according to known conditions such as the main channel CSI and the statistical parameters of the eavesdropping channel, and selects the duplex mode with the goal of maximizing the average secure capacity. At this time, the average secure capacity of the system is:

[0063] Advantages of the present invention:

[0064] 1. In the prior art, it is necessary to ensure that the main channel and the eavesdropping channel are completely independent. Assuming that the instantaneous channel gain of the eavesdropping channel is known, the interference signal is designed to realize the interference on the eavesdropping channel. However, the design of the artificial interference signal in the present invention is independent of the eavesdropping channel and does not need to rely on the instantaneous channel gain of the eavesdropping channel to design the interference signal. The present invention can use any artificial interference signal to realize the interference on the eavesdropping channel.

[0065] 2. The prior art usually relies on the independence of the main channel and the eavesdropping channel. However, the method of the present invention proposes a relay cooperative interference physical layer secure transmission scheme based on FD / HD for the correlation between PLC channels, so that the transmitting end node A and the receiving end node B respectively send confidential signals and artificial interference signals, and the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal in the corresponding duplex mode, and can still ensure the system security when the main channel and the eavesdropping channel are correlated.

[0066] 3. The power line adaptive relay cooperative physical layer secure transmission method described in the present invention can adaptively select the FD or HD mode according to the main channel CSI and the statistical parameters of the eavesdropping channel to maximize the average secure capacity of the system. This part is proposed for the respective advantages and disadvantages of FD and HD. There is no method for adaptively adjusting the duplex mode in the prior art, and the present invention has certain application prospects and progressiveness. Description of the drawings

[0067] Figure 1 is a schematic diagram of the principle of configuring each node in the PLC relay communication system;

[0068] Figure 2 is a schematic diagram of the model of the PLC relay communication system;

[0069] Figure 3 is a schematic diagram of the principle of a relay cooperative transmission mechanism based on the full-duplex / semi-duplex mode; among them, Figure 3 a is a schematic diagram of the principle of a relay cooperative transmission mechanism based on the full-duplex mode; Figure 3 b is a schematic diagram of the principle of a relay cooperative transmission mechanism based on the semi-duplex mode;

[0070] Figure 4 is a curve graph of the system average security capacity varying with SNR; among them, Figure 4 a is the curve graph of the system average security capacity varying with SNR when the channel correlation coefficient ρ = 0.3 and the first self-interference parameter δ a takes different values; Figure 4 b is the curve graph of the system average security capacity varying with SNR when the channel correlation coefficient ρ = 0.9 and the first self-interference parameter δ a takes different values. Specific implementation manners

[0071] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0072] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0073] Embodiment 1:

[0074] Refer to Figure 1 and Figure 2 to illustrate this embodiment. The power line adaptive relay cooperative physical layer security transmission method described in this Embodiment 1 is implemented based on a PLC relay communication system. The PLC relay communication system includes a transmitting end node A, a receiving end node B, a relay node R, and an eavesdropping node E. The eavesdropping node E is used to steal the information on the communication link between the relay node R and the receiving end node B. The method includes the following steps:

[0075] S1. The transmitting end node A sends a pilot signal to the relay node R, and in combination with the pulse noise suppression and channel estimation method, the relay node R estimates the channel instantaneous gain h AR ;

[0076] h AR is the channel instantaneous gain from the transmitting end node A to the relay node R;

[0077] S2. Determine whether the channel of the PLC relay communication system is symmetric. If the determination result is yes, execute step S3; if the determination result is no, execute step S4;

[0078] S3. The receiving end node B sends a pilot signal to the relay node R, and the relay node R estimates the channel instantaneous gain h by combining impulse noise suppression and channel estimation methods BR , and execute step S6; where, h BR =h RB ;

[0079] h BR is the channel instantaneous gain from the receiving end node B to the relay node R;

[0080] h RB is the channel instantaneous gain from the relay node R to the receiving end node B;

[0081] S4. The relay node R sends a pilot signal to the receiving end node B, and the receiving end node B estimates the channel instantaneous gain h by combining impulse noise suppression and channel estimation methods RB , and execute step S5;

[0082] h RB is the channel instantaneous gain from the relay node R to the receiving end node B;

[0083] S5. The receiving end node B sends the channel instantaneous gain h RB and the pilot signal to the relay node R, and the relay node R receives the channel instantaneous gain h RB and the pilot signal. At the same time, the relay node R estimates the channel instantaneous gain h according to the received pilot signal by using impulse noise suppression and channel estimation methods BR , and execute step S6;

[0084] h BR is the channel instantaneous gain from the receiving end node B to the relay node R;

[0085] S6. The relay node R calculates the average security capacity of the full-duplex mode and the average security capacity of the half-duplex mode

[0086]

[0087] S7. The relay node R judges and in terms of magnitude. If , it is determined that the relay node R and the receiving end node B adopt the full-duplex mode, and execute step S8; otherwise, it is determined that the relay node R and the receiving end node B adopt the half-duplex mode, and execute step S9;

[0088] S8. The relay node R sends a broadcast to notify the transmitting node A and the receiving node B that the relay node R and the receiving node B adopt the full-duplex mode. Meanwhile, it also sends a broadcast to notify the receiving node B of the channel instantaneous gain h BR so as to complete the configuration of the PLC relay communication system and execute step S10;

[0089] S9. The relay node R sends a broadcast to notify the transmitting node A and the receiving node B that the relay node R and the receiving node B adopt the half-duplex mode. Meanwhile, it also sends a broadcast to notify the receiving node B of the channel instantaneous gain h BR so as to complete the configuration of the PLC relay communication system and execute step S11;

[0090] S10. In each time slot, the transmitting node A sends a confidential signal to the relay node R. Meanwhile, the receiving node B sends an artificial interference signal to the relay node R. In the current time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal in the previous time slot to the receiving node B. The receiving node B demodulates the received mixed signal by using the channel instantaneous gain h BR and the channel instantaneous gain h RB to achieve the secure transmission of the confidential signal;

[0091] S11. In the current time slot, the transmitting node A sends a confidential signal to the relay node R. Meanwhile, the receiving node B sends an artificial interference signal to the relay node R. In the next time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal to the receiving node B. The receiving node B demodulates the received mixed signal by using the channel instantaneous gain h BR and the channel instantaneous gain h RB to achieve the secure transmission of the confidential signal.

[0092] In specific applications, the PLC relay communication system adjusts the working state of the transmitting node A according to the configuration of each node. Specifically, the transmitting node A is always in the half-duplex mode, but the transmitting node A needs to adjust its working state according to the duplex modes of the relay node R and the receiving node B. Among them, when the relay node R and the receiving node B adopt the full-duplex mode, the transmitting node A can send a signal once in one time slot, while when the relay node R and the receiving node B adopt the half-duplex mode, the transmitting node A can send a signal once in two time slots. In actual signal transmission, the receiving node B demodulates the received signal according to the configured channel instantaneous gain h BR and the channel instantaneous gain h RB estimated by itself to achieve the secure and accurate transmission of the signal. The demodulation process of the signal can be realized by existing technical means.

[0093] The design of the artificial interference signal in the present invention is independent of the eavesdropping channel, and it does not need to rely on the instantaneous channel gain of the eavesdropping channel to design the interference signal. The present invention can use any artificial interference signal to achieve interference on the eavesdropping channel. The design of the artificial interference signal is independent of the eavesdropping channel and does not require the instantaneous channel gain of the eavesdropping channel, and it can still ensure security when the main channel and the eavesdropping channel are correlated. It is very difficult to obtain the instantaneous channel gain of the eavesdropping channel in practical applications. Other methods in the prior art assume that the eavesdropping channel gain is known when calculating the average security capacity of the duplex mode in practical applications, and this implementation concept does not conform to the actual situation.

[0094] The present invention considers the problem that the channels in the PLC relay communication system may be correlated and affect the secure transmission performance, and proposes a relay cooperative interference physical security layer transmission scheme based on FD / HD. The transmitting end node A and the receiving end node B respectively send the confidential signal and the artificial interference signal simultaneously, and the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal. Specifically, it further considers that the full-duplex (FD) mode has higher spectral efficiency, but its performance is limited by RSI, and the performance of the FD system is not necessarily better than that of the HD system in practical applications. In order to find a balance between the spectral efficiency loss of the half-duplex (HD) and the self-interference problem of the FD, an adaptive relay cooperative secure transmission mechanism is proposed. Calculate the average security capacity of the full-duplex / half-duplex (FD / HD) mode respectively, and select the duplex mode with the goal of maximizing the average security capacity as the average security capacity of the system which is: Thus, the security of the PLC relay communication system transmission is improved.

[0095] Furthermore, in step S6, the relay node R calculates the average security capacity of the full-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the full-duplex mode, the statistical parameters of the eavesdropping channel gain, and the statistical parameters of the interference channel gain At the same time, the relay node R also calculates the average security capacity of the half-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the half-duplex mode and the statistical parameters of the eavesdropping channel gain

[0096] The statistical parameters of the eavesdropping channel gain include μ RE and where μ RE is the mean of the natural logarithm of the eavesdropping channel gain, is the variance of the natural logarithm of the eavesdropping channel gain; the statistical parameters of the interference channel gain include μ BE and where μ BE is the mean of the natural logarithm of the interference channel gain, is the variance of the natural logarithm of the interference channel gain;

[0097] The wiretap channel is the channel between the relay node R and the eavesdropping node E; the interference channel is the channel between the receiving end node B and the eavesdropping node E.

[0098] In this preferred embodiment, a specific method for calculating the average secure capacity in the full-duplex mode and the average secure capacity in the half-duplex mode is given. Considering the received signal-to-noise ratio at the receiving end node B in the full-duplex mode, the statistical parameters of the wiretap channel gain, and the statistical parameters of the interference channel gain, the following is obtained using the above parameters This method does not require the instantaneous channel gain of the wiretap channel to be known; it also considers the received signal-to-noise ratio at the receiving end node B in the half-duplex mode and the statistical parameters of the wiretap channel gain, and obtains the following using the above parameters This calculation process also does not require the instantaneous channel gain of the wiretap channel to be known, which is more in line with the actual situation.

[0099] Furthermore, in step S6, the relay node R calculates the average secure capacity in the full-duplex mode The implementation method includes:

[0100] S611. Calculate the average capacity of the main channel in the full-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the full-duplex mode where the main channel is composed of the channel between the transmitting end node A and the relay node R and the channel between the relay node R and the receiving end node B;

[0101] S612. Calculate the average capacity of the wiretap channel in the full-duplex mode according to the statistical parameters of the wiretap channel gain and the statistical parameters of the interference channel gain in the full-duplex mode

[0102] S613. Calculate the average secure capacity in the full-duplex mode according to and

[0103] In this preferred embodiment, the average capacity of the wiretap channel in the full-duplex mode is calculated using the statistical parameters of the wiretap channel gain and the statistical parameters of the interference channel gain in the full-duplex mode without the need for the instantaneous channel gain of the wiretap channel, and has general applicability.

[0104] Furthermore, in step S611,

[0105] where

[0106] where P A is the transmission power of the transmitting end node A, P​​B is the transmit power of the receiving end node B, P R is the transmit power of the relay node R, S R is the pulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no pulse noise occurs at the relay node R; S R = 1, represents the probability that pulse noise occurs at the relay node R; S B is the pulse noise occurrence state in the channel noise at the receiving end node B; S B = 0, represents the probability that no pulse noise occurs at the receiving end node B; S B = 1, represents the probability that pulse noise occurs at the receiving end node B; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R, is the total noise power of the receiving end node B, and is the RSI noise power of the receiving end node B, is the channel noise power of the receiving end node B, G FD is the gain coefficient of the relay node R in the amplify-and-forward protocol under the full-duplex mode.

[0107] In application, the total noise of the node working in the full-duplex state includes channel noise and RSI noise; among them, the channel noise includes background noise and pulse noise. When S R = 0, S R = 1, When S B = 0, S B = 1, Among them, is the background noise power in the channel noise, is the channel noise power, which is also the sum of the background noise power and the pulse noise power.

[0108] The power line channel noise can be mainly divided into two categories: background noise and pulse noise. For the convenience of analysis, the Bernoulli-Gaussian (BG) noise model is adopted, and its PDF form is:

[0109]

[0110] where: p0 = 1 - pb , p1 = p b , p b is the occurrence probability of impulse noise; and are the background noise and impulse noise power respectively, and and are the PDFs of Gaussian distributions with mean 0 and variances and respectively. Assume that the noises at all nodes are independent and identically distributed.

[0111] Furthermore, in step S612, calculating the average capacity of the eavesdropping channel in full-duplex mode is implemented as follows:

[0112] S612-1. Calculate the first probability density function f JP,LN (x1, x2) with respect to x1 and x2 according to the statistical parameters of the eavesdropping channel gain and the interference channel gain in full-duplex mode, specifically:

[0113]

[0114] where x1 is a variable following a Log-N distribution with mean 2μ RE and variance , and x2 is a variable following a Log-N distribution with mean 2μ BE and variance , σ RE is the standard deviation of the natural logarithm of the eavesdropping channel gain, σ BE is the standard deviation of the natural logarithm of the interference channel gain, and ρ RE,BE is the correlation coefficient between the natural logarithm of the eavesdropping channel gain and the natural logarithm of the interference channel gain;

[0115] S612-2. Obtain the average capacity JP,LN of the eavesdropping channel in full-duplex mode according to the first probability density function f specifically:

[0116]

[0117] The

[0118] where P A is the transmit power of the transmitting node A, P B is the transmit power of the receiving node B, P R is the transmit power of the relay node R, S Ris the occurrence state of impulsive noise in the channel noise at the relay node R; when S R = 0, represents the probability that no impulsive noise occurs at the relay node R; when S R = 1, represents the probability that impulsive noise occurs at the relay node R; when S E is the occurrence state of impulsive noise in the channel noise at the eavesdropping node E; when S E = 0, represents the probability that no impulsive noise occurs at the eavesdropping node E; when S E = 1, represents the probability that impulsive noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R.

[0119] Furthermore, in step S613, according to and calculate the average secrecy capacity of the full-duplex mode, and the implementation method is:

[0120] wherein, represents taking the maximum value between 0 and both.

[0121] Furthermore, in step S6, the relay node R calculates the average secrecy capacity of the half-duplex mode, and the implementation method includes:

[0122] S621. According to the received signal-to-noise ratio at the receiving end node B in the half-duplex mode, calculate the average capacity of the main channel in the half-duplex mode, where the main channel is composed of the channel between the transmitting end node A and the relay node R, and the channel between the relay node R and the receiving end node B;

[0123] S622. According to the statistical parameters of the eavesdropping channel gain in the half-duplex mode, calculate the average capacity

[0124] of the eavesdropping channel in the half-duplex mode; and calculate the average secrecy capacity

[0125] Further, in step S621,

[0126] wherein and

[0127] where P A is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the pulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no pulse noise occurs at the relay node R; when S R = 1, represents the probability that pulse noise occurs at the relay node R; S B is the pulse noise occurrence state in the channel noise at the receiving end node B; when S B = 0, represents the probability that no pulse noise occurs at the receiving end node B; when S B = 1, represents the probability that pulse noise occurs at the receiving end node B; is the channel noise power of the relay node R, is the channel noise power of the receiving end node B, G HD is the gain coefficient of the relay node R in the amplify-and-forward protocol in the half-duplex mode.

[0128] Further, in step S622, calculating the average capacity of the wiretap channel in the half-duplex mode is implemented as follows:

[0129] S622-1. According to the statistical parameters of the wiretap channel gain in the half-duplex mode, calculate the second probability density function f LN (x1) of x1, specifically:

[0130]

[0131] where x1 is a variable that follows a Log-N distribution with a mean of 2μ RE and a variance of , and σ RE is the standard deviation of the natural logarithm of the wiretap channel gain;

[0132] S622-2. According to the second probability density function f LN (x1), calculate the average capacity of the wiretap channel in the half-duplex mode, specifically:

[0133]

[0134] The said

[0135] Among them, P A is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the impulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no impulse noise occurs at the relay node R; when S R = 1, represents the probability that impulse noise occurs at the relay node R; S E is the impulse noise occurrence state in the channel noise at the eavesdropping node E; when S E = 0, represents the probability that no impulse noise occurs at the eavesdropping node E; when S E = 1, represents the probability that impulse noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the channel noise power of the relay node R.

[0136] Furthermore, in step S623, according to and calculate the average secure capacity of the half-duplex mode, and the implementation method is:

[0137] Among them, represents taking the maximum value between 0 and the two.

[0138] Figure 3 is the schematic diagram of the principle of the relay cooperative transmission mechanism based on the full-duplex / half-duplex mode;

[0139] When applied, for the schematic diagram of the principle of the relay cooperative transmission mechanism based on the full-duplex mode, see Figure 3 a; the specific process is as follows: In the i-th time slot, A and B respectively and simultaneously send the confidential signal x A (i) and the artificial interference signal x BN (i), among which, x A (i) and x BN (i) are both power-normalized signals. Under the amplify-and-forward (AF) protocol, R forwards the received signal x R (i) = G FD yR (i - 1). Where: G FD is the gain coefficient of the relay node R under the amplify-and-forward protocol in the full-duplex mode, and y R (i - 1) is the received signal at R in the (i - 1)-th time slot. At this time, the received signals at R, B, and E are respectively:

[0140]

[0141]

[0142]

[0143] In the formula: P A and P B are the transmission powers of A and B respectively; h uv (u, v ∈ {A, B, R, E}) is the instantaneous channel gain between node u and node v; and are the channel noise interferences at R, B, and E respectively, and their noise powers are and S v ∈ {0, 1}; when S v = 0, the noise power S v = 1, the noise power n ε,R (i) and n ε,B (i) are the RSI at R and B respectively, and they are usually modeled as Gaussian distributions with a mean of 0 and a variance of , its variance is related to the transmission power, δ a and δ b are both residual self-interference RSI parameters. Among them, δ a and δ b are the first and second self-interference parameters respectively, and δ a > 0, δ b ∈ [0, 1]; since RSI is independent of the channel noise, the interference signals at R and B can be expressed as The total noise power

[0144] When applied, for the schematic diagram of the principle of the relay cooperation transmission mechanism based on the half-duplex mode, see Figure 3 b. The specific process is as follows: In the (2i - 1)-th time slot, A and B simultaneously send the confidential signal x A (i) and the artificial interference signal x BN (i) respectively, and the received signal at R is:

[0145]

[0146] In the formula: is the channel noise interference at the R in the (2i - 1)-th time slot.

[0147] In the 2i-th time slot, R forwards the received signal x in the previous time slot by the AF protocol R (i) = G HD y R (2i - 1), where: G HD is the gain coefficient of the relay node R in the amplify-and-forward protocol in the half-duplex mode. The received signals at B and E are respectively:

[0148]

[0149]

[0150] In the formula: and are respectively the channel noise interferences at B and E in the 2i-th time slot.

[0151] Verification test:

[0152] Through the following verification test, the technical effects of the present invention are illustrated, specifically:

[0153] The Monte-Carlo method is adopted to simulate the average secure capacity under the relay cooperation physical layer secure transmission method. Through the comparison between the simulation results and the theoretical analysis results, the reliability of the theoretical analysis of the present invention is verified. The superiority of the adaptive relay performance is proved through the comparison of the secure performance in the FD (full-duplex), HD (half-duplex), and HY (adaptive switching between full-duplex and half-duplex) modes. The HY mode is the mode of adaptive switching between full-duplex and half-duplex of the method of the present invention.

[0154] The topology of the PLC relay communication system is as Figure 2 shown, and the parameter settings are as follows: The noise parameter p b = 0.01, η = 10, and the average signal-to-noise ratio SNR is defined as Cable length: l1 = l2 = 50m, l3 = 25m, l4 = 25m; Transmission power P A = P B = P R = 1W; The RSI parameters of each node are both composed of δ a and δ b , where, δ a is the first self-interference parameter, δ b is the second self-interference parameter. Let the δ b of each node be 0, and let the δ a of all nodes take the same value; The channel variance is in decibels (dB), is to normalize the fading envelope, let u, v ∈ {A, B, R, E}. According to the actual measurement results, the signal fading per kilometer in narrowband PLC is 40 - 100 dB. In the range of 500 kHz - 20 MHz, the average signal fading in a 100 - m cable is 12 - 55 dB. Assuming that the system operates in the broadband range, the fading is 30 dB per 100 m (it is easy to obtain the line loss parameters after determining the working frequency band in actual applications).

[0155] The curves of the average secure capacity of the system versus SNR in FD, HD, and HY modes are as Figure 4 shown. From Figure 4 a and Figure 4 b, it can be seen that as the channel correlation increases, the degree of coincidence between the theoretical results and the simulation results in the figure decreases, that is, the accuracy of the theoretical analysis results decreases to a certain extent, but the overall trend is consistent with the simulation results.

[0156] Respectively comparing the FD and HD performances from Figure 4 a and Figure 4 b, it can be seen that in the FD mode, when the SNR is low, its secure capacity is better than that of the HD mode; when the SNR is high, the secure capacity is worse than that of the HD mode. The HY mode operates in the FD mode when the SNR is small and in the HD mode when the SNR is large, so it has more excellent performance.

[0157] Comparing Figure 4 a and Figure 4 b, it can be seen that by adopting the relay cooperative interference technology, in the FD and HD modes, the channel correlation can improve the system security performance to a certain extent. The higher the channel correlation, the stronger the system security performance.

[0158] In summary, from Figure 4 it can be seen that by using the method of the present invention, the duplex mode of each node in the PLC relay communication system can be adaptively switched (HY mode), thereby improving the system security performance.

[0159] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed as long as they do not depart from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. Power line adaptive relay cooperative physical layer security transmission method, which is implemented based on a PLC relay communication system. The PLC relay communication system includes a transmitting end node A, a receiving end node B, a relay node R, and an eavesdropping node E. The eavesdropping node E is used to steal information on the communication link between the relay node R and the receiving end node B. It is characterized in that, The method includes the following steps: S1. The transmitting end node A sends a pilot signal to the relay node R, and the relay node R estimates the channel instantaneous gain h by combining the pulse noise suppression and channel estimation methods AR ; h AR is the instantaneous channel gain from the transmitting end node A to the relay node R; S2. Determine whether the channel of the PLC relay communication system is symmetric. If the determination result is yes, execute step S3; if the determination result is no, execute step S4; S3. The receiving end node B sends a pilot signal to the relay node R, and the relay node R estimates the channel instantaneous gain h by combining the pulse noise suppression and channel estimation methods. BR , and perform step S6; where h BR = h RB ; h BR is the instantaneous channel gain between the receiving end node B and the relay node R; h RB is the instantaneous channel gain between the relay node R and the receiving end node B; S4. The relay node R sends a pilot signal to the receiving end node B, and the receiving end node B estimates the channel instantaneous gain h by combining the pulse noise suppression and channel estimation methods RB , and perform step S5; h RB is the instantaneous channel gain between the relay node R and the receiving node B; S5. The receiving end node B sends the channel instantaneous gain h to the relay node R RB and the pilot signal, and the relay node R receives the channel instantaneous gain h RB and the pilot signal. Meanwhile, the relay node R estimates the channel instantaneous gain h according to the received pilot signal by using the impulse noise suppression and channel estimation method BR , and executes step S6; h BR is the instantaneous channel gain between the receiving end node B and the relay node R; S6. The relay node R calculates the average secure capacity in the full-duplex mode and the average secure capacity in the half-duplex mode S7. The relay node R judges and the magnitudes of. If it is determined that the relay node R and the receiving end node B adopt the full-duplex mode, and step S8 is executed; otherwise, it is determined that the relay node R and the receiving end node B adopt the half-duplex mode, and step S9 is executed; S8. The relay node R sends a broadcast to notify the transmitting node A and the receiving node B that the relay node R and the receiving node B adopt the full-duplex mode. Meanwhile, it also sends a broadcast to notify the receiving node B of the channel instantaneous gain h BR so as to complete the configuration of the PLC relay communication system and execute step S10; S9. The relay node R sends a broadcast to notify the transmitting node A and the receiving node B that the relay node R and the receiving node B adopt the half-duplex mode. At the same time, it also sends a broadcast to notify the receiving node B of the channel instantaneous gain h BR so as to complete the configuration of the PLC relay communication system and execute step S11; S10. At each time slot, the transmitting end node A sends a confidential signal to the relay node R. Meanwhile, the receiving end node B sends an artificial interference signal to the relay node R. At the current time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal in the previous time slot to the receiving end node B, and the receiving end node B demodulates the received mixed signal by using the channel instantaneous gain h BR and the channel instantaneous gain h RB to realize the secure transmission of the confidential signal; S11. At the current time slot, the transmitting end node A sends a confidential signal to the relay node R. Meanwhile, the receiving end node B sends an artificial interference signal to the relay node R. At the next time slot, the relay node R forwards the mixed signal of the confidential signal and the artificial interference signal to the receiving end node B, and the receiving end node B demodulates the received mixed signal by using the channel instantaneous gain h BR and the channel instantaneous gain h RB to achieve the secure transmission of the confidential signal.

2. The power line adaptive relay cooperation physical layer security transmission method according to claim 1, characterized in that In step S6, relay node R calculates the average secure capacity of the full-duplex mode based on the received signal-to-noise ratio at receiving end node B, the statistical parameters of the eavesdropping channel gain, and the statistical parameters of the interference channel gain in the full-duplex mode. Meanwhile, relay node R also calculates the average secure capacity of the half-duplex mode based on the received signal-to-noise ratio at receiving end node B and the statistical parameters of the eavesdropping channel gain in the half-duplex mode. The statistical parameters of the eavesdropping channel gain include μ RE and where μ RE is the mean of the natural logarithm of the eavesdropping channel gain, and is the variance of the natural logarithm of the eavesdropping channel gain; the statistical parameters of the interference channel gain include μ BE and where μ BE is the mean of the natural logarithm of the interference channel gain, and is the variance of the natural logarithm of the interference channel gain; The wiretap channel is the channel between the relay node R and the wiretap node E; the interference channel is the channel between the receiving end node B and the wiretap node E.

3. The power line adaptive relay cooperation physical layer security transmission method according to claim 2, characterized in that In step S6, the relay node R calculates the average secure capacity in the full-duplex mode The implementation method includes: S611. Calculate the average capacity of the main channel in the full-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the full-duplex mode wherein the main channel is composed of the channel between the transmitting end node A and the relay node R and the channel between the relay node R and the receiving end node B ​ S612. Calculate the average capacity of the eavesdropping channel in the full-duplex mode based on the statistical parameters of the eavesdropping channel gain and the statistical parameters of the interference channel gain in the full-duplex mode. S613. Calculate the average security capacity of the full-duplex mode according to and 4. The power line adaptive relay cooperation physical layer security transmission method according to claim 3, wherein In step S611, Among them, P A is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the occurrence state of impulse noise in the channel noise at the relay node R; when S R = 0, represents the probability that no impulse noise occurs at the relay node R; S R = 1, represents the probability that impulse noise occurs at the relay node R; S B is the occurrence state of impulse noise in the channel noise at the receiving end node B; S B = 0, represents the probability that no impulse noise occurs at the receiving end node B; S B = 1, p SB represents the probability that impulse noise occurs at the receiving end node B; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R, is the total noise power of the receiving end node B, and is the RSI noise power of the receiving end node B, is the channel noise power of the receiving end node B, G FD is the gain coefficient of the relay node R in the amplify-and-forward protocol in the full-duplex mode.

5. The power line adaptive relay cooperative physical layer secure transmission method according to claim 3, wherein In step S612, calculate the average capacity C of the eavesdropping channel in the full-duplex mode E FD The implementation method includes: S612-1. Calculate the first probability density function f JP,LN JP,LN (x1, x2) with respect to x1 and x2 according to the statistical parameters of the eavesdropping channel gain and the statistical parameters of the interference channel gain in the full-duplex mode, specifically as follows: where x1 is a variable following a Log-N distribution with a mean of 2μ RE and a variance of , x2 is a variable following a Log-N distribution with a mean of 2μ BE and a variance of , σ RE is the standard deviation of the natural logarithm of the eavesdropping channel gain, σ BE is the standard deviation of the natural logarithm of the interference channel gain, and ρ RE,BE is the correlation coefficient between the natural logarithm of the eavesdropping channel gain and the natural logarithm of the interference channel gain; S612-2. Obtain the average capacity of the eavesdropping channel in the full-duplex mode according to the first probability density function f JP,LN (x1, x2) Specifically: Among them, P A is the transmission power of the transmitting node A, P B is the transmission power of the receiving node B, P R is the transmission power of the relay node R, S R is the occurrence state of impulse noise in the channel noise at the relay node R; when S R = 0, represents the probability that no impulse noise occurs at the relay node R; when S R = 1, p SR represents the probability that impulse noise occurs at the relay node R; S E is the occurrence state of impulse noise in the channel noise at the eavesdropping node E; when S E = 0, represents the probability that no impulse noise occurs at the eavesdropping node E; when S E = 1, represents the probability that impulse noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the total noise power of the relay node R, and is the RSI noise power of the relay node R, is the channel noise power of the relay node R.

6. The power line adaptive relay cooperation physical layer secure transmission method according to claim 3, characterized in that In step S613, according to and calculate the average security capacity of the full-duplex mode The implementation method is as follows: Among them, represents taking the maximum value between 0 and both.

7. The power line adaptive relay cooperation physical layer security transmission method according to claim 2, wherein In step S6, relay node R calculates the average secure capacity in the half-duplex mode The implementation method includes: S621. Calculate the average capacity of the primary channel in the half-duplex mode according to the received signal-to-noise ratio at the receiving end node B in the half-duplex mode. Calculate the average capacity of the primary channel in the half-duplex mode. Wherein, the primary channel is composed of the channel between the transmitting end node A and the relay node R, and the channel between the relay node R and the receiving end node B. S622. Calculate the average capacity of the eavesdropping channel in the half-duplex mode according to the statistical parameters of the eavesdropping channel gain in the half-duplex mode S623. Calculate the average security capacity in the half-duplex mode according to and ​ 8. The power line adaptive relay cooperation physical layer secure transmission method according to claim 7, characterized in that In step S621, and Among them, P A is the transmission power of the transmitting end node A, P B is the transmission power of the receiving end node B, P R is the transmission power of the relay node R, S R is the pulse noise occurrence state in the channel noise at the relay node R; when S R = 0, represents the probability that no pulse noise occurs at the relay node R; when S R = 1, represents the probability that pulse noise occurs at the relay node R; S B is the pulse noise occurrence state in the channel noise at the receiving end node B; when S B = 0, p SB represents the probability that no pulse noise occurs at the receiving end node B; when S B = 1, represents the probability that pulse noise occurs at the receiving end node B; is the channel noise power of the relay node R, is the channel noise power of the receiving end node B, G HD is the gain coefficient of the relay node R in the amplify-and-forward protocol under the half-duplex mode.

9. The power line adaptive relay cooperation physical layer security transmission method according to claim 7, characterized in that In step S622, calculate the average capacity of the eavesdropping channel in the half-duplex mode The implementation manners include: S622-1. Calculate the second probability density function \(f\) of \(x1\) according to the statistical parameters of the eavesdropping channel gain in the half-duplex mode, specifically as follows: LN (x1), specifically: where x1 is a variable that follows a Log-N distribution with a mean of 2μ RE and a variance of , and σ RE is the standard deviation of the natural logarithm of the eavesdropping channel gain; S622-2. Calculate the average capacity of the wiretap channel in the half-duplex mode according to the second probability density function f LN (x1) Specifically: Among them, P A is the transmission power of the transmitting node A, P B is the transmission power of the receiving node B, P R is the transmission power of the relay node R, S R is the occurrence state of impulse noise in the channel noise at the relay node R; when S R = 0, represents the probability that no impulse noise occurs at the relay node R; when S R = 1, represents the probability that impulse noise occurs at the relay node R; S E is the occurrence state of impulse noise in the channel noise at the eavesdropping node E; when S E = 0, p SE represents the probability that no impulse noise occurs at the eavesdropping node E; when S E = 1, represents the probability that impulse noise occurs at the eavesdropping node E; is an intermediate variable, is the channel noise power of the eavesdropping node E; is the channel noise power of the relay node R.

10. The power line adaptive relay cooperation physical layer security transmission method according to claim 7, wherein In step S623, according to and calculate the average security capacity in the half-duplex mode The implementation method is as follows: Among them, represents taking the maximum value between 0 and both.

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