CN111049552B - Method, device and device for secure multi-hop data transmission based on power line communication - Google Patents

Abstract

Embodiments of the present invention relate to a method, device, and device for secure multi-hop data transmission based on power line communication, including acquiring channel state information and communication parameters of each communication channel on a multi-hop broadband power line, and constructing a communication channel with each communication channel according to each communication parameter. One-to-one corresponding channel transfer function, each communication parameter is combined with the MK model to construct an actual channel model for each channel transfer function; a power line communication system model is established based on the actual channel model; the joint transceiver matrix is input into the power line communication system model to obtain the objective function; The function is optimized and solved by iterative distributed algorithm, and the safe rate of multi-hop data safe transmission on the power line communication system model is obtained. The power line can transmit data at a safe rate to ensure safe communication and prevent eavesdropping users from stealing data. The technical problem of low security of data transmission under the multi-hop broadband power line communication system in the prior art is solved.

Description

Multi-hop data security transmission method, device and equipment based on power line communication

technical field

The present invention relates to the technical field of data transmission security, and in particular, to a method, device and device for multi-hop data security transmission based on power line communication.

Background technique

Multi-hop broadband power line communication refers to the use of power lines as a medium for signal transmission. When sending signals, modulation technology is used to modulate data, and information-carrying signals are loaded on the current, and then power lines are used for transmission; signals are received at the receiving end At the time, the received signal is first passed through the filter, then the modulated signal is taken out, and then the original communication signal can be obtained through demodulation technology, and transmitted to the telephone or computer to realize the transmission of information.

At present, power lines have been distributed in every household, and the scope of popularization is extremely wide. There is no need to add dedicated lines. If the power line is used as a medium to realize the communication between the mobile terminal and the electric energy meter in the station area, it will reduce the need for the power grid to obtain electric energy data. cost, and can improve the use value of the power line. However, the communication data between the mobile terminal and the electric energy meter in the station area is relatively large. Such huge and important data is transmitted on the power line with broadcast characteristics, and the communication data needs to be transmitted securely and confidentially. How to realize the data on the power line? It is particularly important to ensure the security of the physical layer of multi-hop broadband power line communication.

Therefore, how to realize the physical layer security of the multi-hop broadband power line communication and ensure the secure communication between the mobile terminal in the station area and the electric energy meter has become an important technical problem to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method, device and device for secure multi-hop data transmission based on power line communication, which are used to solve the problem of low security of data transmission in the multi-hop broadband power line communication system in the prior art, and problems in the power line communication system. The technical problem that communication data is easy to be stolen.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

A multi-hop data security transmission method based on power line communication, applied to communication data transmission between a mobile terminal in a station area and an electric energy meter, comprising the following steps:

S1. Obtain the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and construct a channel transfer function corresponding to each of the communication channels according to each of the communication parameters. Each of the communication parameters is combined with the MK model. each of the channel transfer functions constructs an actual channel model;

S2. Establish a power line communication system model according to the actual channel model;

S3. Input the joint transceiver matrix into the power line communication system model to obtain the objective function;

S4. Use an iterative distributed algorithm to optimize and solve the objective function to obtain a safe rate of multi-hop data safe transmission on the power line communication system model.

Preferably, the communication parameters include the number of paths of each of the communication channels, the transmission distance of the paths, the signal frequency and the communication nodes:

Wherein, the communication node can be used to eavesdrop on the user to steal the transmission data on the communication channel.

Preferably, the actual channel model of the multi-hop broadband power line is based on the following formula:

c₀为光速，ε_r为所述多跳宽带电力线的介电常数。Among them, i is the number of the path, _gi is the weighting coefficient of each path and the value is a natural number not greater than 1, A(f, d _i ) is the attenuation coefficient of the communication channel, α ₀ , α ₁ and k are all is the attenuation parameter, k is 0.5 to 1, d _i is the transmission distance of the i-th path, and τ _i is the delay on path i

c ₀ is the speed of light, and ε _r is the dielectric constant of the multi-hop broadband power line.

Preferably, the power line communication system model includes a transmitter, a relay and a receiver, and based on additive white Gaussian noise, the mean value and variance ^σ2 of all the communication nodes used to receive data are processed to obtain the The channel matrix of the link between the transmitter, the relay and the receiver.

Preferably, the joint transceiving matrix includes a transmission precoding matrix, a relay coding matrix and a reception filtering matrix; the objective function includes constraints on each transmit power, the number of communication channels, and the mean square error of the eavesdropping user. Satisfy the transmission power constraints of the transmitting end and the interrupting end, the objective function is:

st: MSE _e,k ≥ε _k

为发射端的发射功率，

为中断端的发射功率，P_sk为发射端的最大发射功率，P_rm为中断端的最大发射功率，ε_k为MSE_e，k的最小值。Wherein, K is a natural number not less than 1, {U _k } is the transmit precoding matrix, {V _m } is the relay coding matrix, {W _k } is the receiving filter matrix, {W _{e , k} } is the reception filter matrix of the eavesdropping user, MSE _k is the mean square error of the receiving end to the transmission data on the multi-hop broadband power line, MSE _{e, k} is the mean square error of the eavesdropping user to the transmission data,

is the transmit power of the transmitter,

is the transmitting power of the interrupted end, P _sk is the maximum transmitting power of the transmitting end, P _rm is the maximum transmitting power of the interrupting end, ε _k is the minimum value of MSE _e,k .

Preferably, the step of optimally solving the objective function according to the iterative distributed algorithm includes:

S41. Set initial values for the matrix variables of the transmit precoding matrix and the relay coding matrix, and use the iterative distributed algorithm to calculate the optimal linear matrix of the reception filter matrix;

S42. according to the objective function, solve and obtain the optimized reception filter matrix of the eavesdropping user;

S43. Based on the optimal linear matrix, the optimized reception filter matrix, and the relay coding matrix obtained iteratively in the step S41, calculate the optimized transmit precoding matrix by using the iterative distributed algorithm;

S44. Based on the optimal linear matrix, the optimized reception filter matrix, and the optimized transmit precoding matrix, calculate and obtain the optimized relay coding matrix by using the iterative distributed algorithm.

Preferably, the calculation step according to the iterative distributed algorithm includes:

和

S01. Initialize, set the iteration counter n=0, the mean square error TMSE ⁽ⁿ⁾ =0 of the receiving end, the matrix variables of the transmit precoding matrix and the relay coding matrix are set to initial value

and

和所述中继编码矩阵

计算得到所述窃听用户的接收滤波矩阵

和所述接收滤波矩阵

S02. the transmit precoding matrix obtained according to the objective function

and the relay coding matrix

Calculate the receiving filter matrix of the eavesdropping user

and the receive filter matrix

与

和

对所述目标函数进行优化，得到更新后的发射预编码矩阵

S03. Iteratively obtained according to the step S02

and

and

Optimizing the objective function to obtain an updated transmit precoding matrix

和

对所述目标函数进行优化，更新得到

并计算所述接收端的均方误差TMSE⁽ⁿ⁺¹⁾；S04. According to the obtained

and

The objective function is optimized and updated to get

And calculate the mean square error TMSE ⁽ⁿ⁺¹⁾ of the described receiving end;

S05. If TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ ≤ ξ, end the iterative distributed algorithm calculation; if TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ >ξ, n=n+1, execute the above Step S02;

Among them, ξ is the numerical difference between the given two iterations before and after.

Preferably, according to the optimal linear matrix, the optimized relay coding matrix and the optimized transmit precoding matrix, the communication rate of the eavesdropping user and the receiving end of the legitimate user is calculated, and the obtained communication rate is obtained according to the following formula. The safe rate of data transmission through the multi-hop broadband power line at the receiving end of the legitimate user, and the safe rate is greater than 0; the formula of the safe rate is:

RateD _k =max(0, comD _k )-max(0, comE), k=1, ...... k

Wherein, comD _k is the communication rate of the receiving end of the legitimate user, and comE is the communication rate of the eavesdropping user.

The present invention also provides a multi-hop data security transmission device based on power line communication, which is applied to the communication data transmission between the mobile terminal and the electric energy meter in the station area, including:

The actual channel model unit is used to construct a channel transfer function corresponding to each of the communication channels according to the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and each of the communication channels. The communication parameters are combined with the MK model to construct an actual channel model for each of the channel transfer functions;

a power line communication system model unit, configured to establish a power line communication system model according to the actual channel model;

establishing an objective function unit for inputting the joint transceiver matrix into the power line communication system model to obtain an objective function;

The computing unit is configured to use an iterative distributed algorithm to optimize and solve the problem according to the objective function, so as to obtain a safe rate of multi-hop data safe transmission on the power line communication system model.

The present invention also provides a device including a processor and a memory;

the memory for storing program codes and transmitting the program codes to the processor;

The processor is configured to execute the above-mentioned method for secure multi-hop data transmission based on power line communication according to the instructions in the program code.

As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

1. The multi-hop data security transmission method based on power line communication includes acquiring the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and constructing a channel transfer function corresponding to each communication channel according to each communication parameter. The communication parameters are combined with the MK model to construct the actual channel model for each channel transfer function; the power line communication system model is established based on the actual channel model; the joint transceiver matrix is input into the power line communication system model to obtain the objective function; the objective function is optimized by using an iterative distributed algorithm. , to obtain the safe rate of multi-hop data safe transmission on the power line communication system model. The multi-hop data security transmission method based on power line communication obtains the security rate of multi-hop data security transmission of power line communication through the joint transceiver matrix and objective function optimized by iterative distribution algorithm, so that the power line can perform data transmission at a safe rate and ensure secure communication. Prevent eavesdropping users from stealing data. Solve the technical problems of low security of data transmission in the multi-hop broadband power line communication system in the prior art, and the communication data in the power line communication system is easy to be stolen;

2. The multi-hop data security transmission device based on power line communication constructs the actual channel model through the actual channel model unit, adopts the establishment objective function unit to input the joint transceiver matrix into the power line communication system model to obtain the objective function, and then adopts the calculation unit according to the objective function. The iterative distributed algorithm is optimized to obtain the safe rate of multi-hop data safe transmission, so that the power line can transmit data at a safe rate, ensure safe communication, and prevent eavesdropping users from stealing data. The technical problems in the prior art that the security of data transmission in the multi-hop broadband power line communication system is low and the communication data in the power line communication system is easy to be stolen are solved.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a flow chart of steps of a method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

FIG. 2 is an amplitude-frequency characteristic curve diagram of a five-path communication channel MK model of the multi-hop data secure transmission method based on power line communication according to an embodiment of the present invention.

FIG. 3 is a frame diagram of data transmission of the multi-hop data security transmission method based on power line communication according to an embodiment of the present invention.

FIG. 4 is a frame diagram of a multi-hop broadband power line communication system for transmitting data according to the multi-hop data security transmission method based on power line communication according to an embodiment of the present invention.

FIG. 5 is a frame diagram of a multi-hop broadband power line communication system based on a multi-hop data secure transmission method based on power line communication according to an embodiment of the present invention.

6 is a flow chart of steps for optimizing and solving the objective function of the method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

FIG. 7 is a framework diagram of steps for iterative distributed algorithm calculation of the method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

FIG. 8 is a change trend diagram of the security rate and the communication rate with the signal-to-noise ratio of the multi-hop data security transmission method based on the power line communication according to the embodiment of the present invention.

FIG. 9 is a convergence diagram of the iterative distribution algorithm of the multi-hop data secure transmission method based on power line communication according to an embodiment of the present invention.

FIG. 10 is a frame diagram of a multi-hop data security transmission device based on power line communication according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the following The described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the examples of this application, for the interpretation of data:

Trunk: It is a transmission path between two switching centers, and a trunk is a physical connection that carries multiple logical links.

Electric energy meter: A device used for electric energy metering of low-voltage users, which can generate various electric energy data.

Physical layer: It is the lowest layer in the computer network model and provides mechanical, electrical, functional and normative characteristics for the creation, maintenance, and removal of physical links required to transmit data.

Shannon's theorem: It gives the upper limit of the channel information transmission rate (bits per second) and the relationship between the channel signal-to-noise ratio and the bandwidth.

Physical layer security has always been focused on multi-hop relay networks to fight against foreign eavesdroppers. The current multi-hop relay networks prevent eavesdroppers from stealing information to improve the security of multi-hop relay networks:

First, a joint relay and interference selection scheme is proposed to improve the security of a multi-hop relay network, but it only selects one node as a relay and does not fully utilize all nodes.

The second is the problem of security resource allocation using a two-hop single-relay network. This problem is to consider the application and non-application of cooperative interference technology in the presence of eavesdroppers, and to enforce the security of IoT communication exposed to eavesdroppers in the transmission design. Enhanced algorithm.

The third is to study the problem of improving the security of important data in the Internet of Things, where eavesdroppers can combine their observations and extremely decode signals. In the presence of cellular interference, in relay-assisted IoT systems, the precoding matrix is optimized when the mean square error (MSE) at the legitimate receiver is at a low value and the MSE at the eavesdropper is large.

Although the physical layer security of multi-hop relay networks has been extensively studied, the resulting physical layer security issues are still a major challenge when the relay network faces interference. In the current research on physical layer security for multi-hop relay networks, a joint power control and beamforming algorithm is proposed to minimize the total transmit power while maintaining the signal-to-interference-plus-noise ratio (SINR) at each receiver. above the expected threshold, and is used to jointly design transmit precoding matrices and receive filter matrices by an iterative distributed algorithm for secure communication over MIMO interference channels via eavesdroppers.

The research on the data transmission security of the multi-hop relay network described above is all theoretical research, and does not consider the use of power lines to realize the data transmission of the multi-hop relay network in practice.

Therefore, the embodiments of the present application provide a multi-hop data security transmission method, device and device based on power line communication, which are used to solve the problem of low security of data transmission in the multi-hop broadband power line communication system in the prior art, and power line communication The technical problem that the communication data in the system is easy to be stolen.

Example 1:

FIG. 1 is a flow chart of steps of a method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

As shown in FIG. 1 , an embodiment of the present invention provides a multi-hop data security transmission method based on power line communication, which is applied to communication data transmission between a mobile terminal in a station area and an electric energy meter, including the following steps:

S1. Obtain the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, construct a channel transfer function corresponding to each communication channel according to each communication parameter, and construct the actual transfer function of each channel with each communication parameter combined with the MK model channel model;

S2. Establish a power line communication system model based on the actual channel model;

S3. Input the joint transceiver matrix into the power line communication system model to obtain the objective function;

S4. Use an iterative distributed algorithm to optimize and solve the objective function, and obtain the safe rate of multi-hop data safe transmission on the power line communication system model.

It should be noted that in the power system, the station area refers to the power supply range or area of a (one) transformer. The mobile terminal may be a PC, a computer, a mobile phone, a handheld computer, and the like.

In the step S1 of the embodiment of the present invention, the channel state information and communication parameters of the communication channel (BPLC) on the multi-hop broadband power line are first obtained, and the channel transfer function corresponding to each power line is constructed according to the communication parameters, that is to say , to use several differential channels of a multi-hop broadband power line to construct several channel transfer functions. The BPLC communication channel has strong frequency selective attenuation characteristics. The relevant parameters of the MK model are obtained from the field measurement data on the multi-hop broadband power line communication channel through the MK model, and the MK model of the BPLC channel is established. The signal used in the MK model The frequency range is 500kHz to 20MHz.

It should be noted that the MK model has been published in the paper "A Multi-Path Signal Propagation Model for the Power Line Channel High-band Multipath Signal Propagation Model" published by Manfred Zimmermann and Klaus Dost. Line Channel in the High Frequency Range), in this embodiment, the construction and working principle of the MK model are not described. In this embodiment, the simulation of the BPLC communication channel of 5 paths of the multi-hop broadband power line communication channel is carried out, and the communication channel attenuation parameters α ₀ =0, α ₁ =1.5×10 ⁻⁹ s/m, k=1 , ε _r =3.8, c ₀ =3.0×10 ⁸ m/s, the channel parameters are shown in Table 1 below:

Table 1 is the parameter table of the communication channel MK model of 5 paths

FIG. 2 is an amplitude-frequency characteristic curve diagram of a five-path communication channel MK model of the multi-hop data secure transmission method based on power line communication according to an embodiment of the present invention.

As shown in Figure 2, from the MK model amplitude-frequency characteristic curve, it can be seen that the frequency fading characteristics of each communication channel on the multi-hop broadband power line are obtained, that is, as the frequency increases, the attenuation increases; Severe frequency selective fading, so far, the channel characteristics of the communication channel can be obtained, and the actual channel model can be constructed.

FIG. 3 is a frame diagram of data transmission of the multi-hop data security transmission method based on power line communication according to an embodiment of the present invention.

As shown in FIG. 3 , in the embodiment of the present invention, the data transmission of power line communication is to send data signals through a signal source, encode the data signals by an encoder, and obtain an encoded data transmission signal. The data transmission signal is sent to the decoder for decoding, and the legitimate user obtains the data signal transmitted on the power line. If the eavesdropping user steals the data signal transmitted in the power line, the eavesdropping user steals the data transmission signal through the eavesdropping channel. Specifically, since there are eavesdropping users in the communication channel of the multi-hop broadband power line, the actual channel model constructed is the eavesdropping channel model.

FIG. 4 is a frame diagram of a multi-hop broadband power line communication system for transmitting data based on a method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention, and FIG. 5 is a multi-hop data transmission based on power line communication according to an embodiment of the present invention. A block diagram of a multi-hop broadband power line communication system with a secure transmission method.

As shown in FIG. 4 and FIG. 5 , in the step S2 of the embodiment of the present invention, because the actual channel model needs to transmit data through the multi-hop broadband power line communication system, K transmitters are used to try to transmit data at M relay nodes. With the help of the data transmission to the corresponding receiving end, since the differential channel of the power line is at most 4, the maximum value of K is 4. The power line communication system model includes a transmitter, a relay, and a receiver. The transmitter, relay, receiver, and the corresponding transmitter-receiver pairs are represented as {S _k }, {R _m }, {D _k }and {( _Sk , Dk)}, where _k =1,...,K; m=1,...,M. Eavesdropping users are represented by E. In addition, the transmitting end {S _k }, the relay {R _m }, the receiving end {D _k } and the eavesdropping user are all set with T _k , Q _m , N _k and _Ne communication channels. It is assumed that the communication channel between all communication nodes experiences a slowly varying actual channel model, and that all receiving communication nodes receive additive white Gaussian noise (AWGN) with mean zero and variance σ ² , and use H _km , G _mk and _Gme denote the channel matrices of the _Sk - _Rm , _Rm - _Dk and _Rm -E links.

It should be noted that if the eavesdropping user tries to steal secret data from the power line, the direct connection between the transmitter and the receiver can be ignored according to the path loss of the power line and the limitation of transmission power. Because the eavesdropping user steals data from the power line, it needs to be close to the receiving end and far away from the transmitting end. When the eavesdropping user is far away, it is difficult for the eavesdropping user to hear the signal coming from the transmitting end. Therefore, it is necessary to protect the communication between the relay and the eavesdropping user. , ignoring the link from the transmitter to the eavesdropping user. When one of the transmitters sends a signal to the corresponding receiver and the other transmitters send signals synchronously, there is an interference channel in the system.

In the embodiment of the present invention, a joint transceiver matrix is introduced into the power line communication system model to obtain an objective function for realizing the physical layer security of multi-hop broadband power line communication, and an iterative distributed algorithm is used to optimize and solve the objective function, and the multi-hop multi-hop power line communication system model is obtained. Safe rate for safe transfer of hop data.

It should be noted that the joint transceiving matrix includes a transmit precoding matrix, a relay coding matrix and a receive filtering matrix. In the realization of multi-hop broadband power line communication in the presence of eavesdropping users, to ensure the safety of the communication between the mobile terminal in the station area and the electric energy meter, at the transmitter and relay, limited by the transmit power, an iterative distributed algorithm is used to precode the transmit Matrix, relay coding matrix, and receiving filter matrix are optimized, and the mean square error of eavesdropping users is greater than that of legitimate users, so as to calculate the safe rate of multi-hop data transmission on the power line communication system model. In the presence of eavesdropping users, the transmission precoding matrix, relay coding matrix, reception filtering matrix and objective function optimized by the iterative distribution algorithm are used to obtain the safe rate of multi-hop data transmission in power line communication, so that the power line can transmit data at a safe rate. transmission to ensure secure communication.

The method for secure multi-hop data transmission based on power line communication provided by the present invention includes acquiring channel state information and communication parameters of each communication channel on a multi-hop broadband power line, and constructing a channel transmission corresponding to each communication channel one-to-one according to each communication parameter. function, each communication parameter is combined with the MK model to construct the actual channel model for each channel transfer function; the power line communication system model is established based on the actual channel model; the joint transceiver matrix is input into the power line communication system model to obtain the objective function; the iterative distributed algorithm is used for the objective function The optimization solution is carried out to obtain the safe rate of multi-hop data safe transmission on the power line communication system model. The multi-hop data security transmission method based on power line communication obtains the security rate of multi-hop data security transmission of power line communication through the joint transceiver matrix and objective function optimized by iterative distribution algorithm, so that the power line can perform data transmission at a safe rate and ensure secure communication. Prevent eavesdropping users from stealing data. The technical problems in the prior art that the security of data transmission in the multi-hop broadband power line communication system is low and the communication data in the power line communication system is easy to be stolen are solved.

In an embodiment of the present invention, the communication parameters include the number of paths of each communication channel, the transmission distance of the paths, the signal frequency and the communication nodes;

Among them, the communication node can be used to eavesdrop on the user to steal the transmission data on the communication channel.

In an embodiment of the present invention, the actual channel model of the multi-hop broadband power line is based on the following formula:

c₀为光速，ε_r为多跳宽带电力线的介电常数。Among them, i is the number of the path, _gi is the weighting coefficient of each path and the value is a natural number not greater than 1, A(f, d _i ) is the attenuation coefficient of the communication channel, α ₀ , α ₁ and k are all attenuations parameter, k is 0.5～1, d _i is the transmission distance of the i-th path, τ _i is the delay on path i

c ₀ is the speed of light, and ε _r is the permittivity of multi-hop broadband power lines.

It should be noted that the size of the attenuation coefficient of the communication channel is determined by the path length and frequency of the communication channel.

In an embodiment of the present invention, the objective function includes constraints on each transmission power, the number of communication channels, and the constraint on the mean square error of the eavesdropping user. When the transmission power constraints of the transmitting end and the interrupting end are satisfied, the following formula is as follows: The formula (13) of the stated objective function is:

st: MSE _e,k ≥ε _k

为发射端的发射功率，

为中断端的发射功率，P_sk为发射端的最大发射功率，P_rm为中断端的最大发射功率，s.t.为subject to的缩写，ε_k为MSE_e，k的最小值。具体地，{U_k}、{V_m}、{W_k}为联合收发矩阵需要优化求解的目的矩阵，{W_e，k}是窃听用户根据自身条件设计的适合于它自己的最优滤波矩阵。其中，s.t.的意思是公式(13)中的

受MSE_e,k≥ε_k、

和

这三个公式的约束。Wherein, K is a natural number not less than 1, {U _k } is the transmit precoding matrix, {V _m } is the relay coding matrix, {W _k } is the receiving filter matrix, {W _e,k } is the reception filter matrix of the eavesdropping user, MSE _k is the mean square error of the receiving end to the data transmitted on the multi-hop broadband power line, MSE _{e, k} is the mean square error of the eavesdropping user to the transmitted data,

is the transmit power of the transmitter,

is the transmitting power of the interrupted end, P _sk is the maximum transmitting power of the transmitting end, P _rm is the maximum transmitting power of the interrupting end, st is the abbreviation of subject to, ε _k is the minimum value of MSE _{e, k} . Specifically, {U _k }, {V _m }, {W _k } are the purpose matrices that need to be optimized and solved for the joint transceiver matrix, and {W _{e, k} } is the optimal filter designed by the eavesdropping user according to his own conditions and suitable for himself. matrix. Among them, st means in formula (13)

Subject to MSE _e,k ≥ε _k ,

and

constraints of these three formulas.

It should be noted that, in the process of data transmission on the multi-hop broadband power line, the communication between the transmitter and the corresponding receiver is completed through two time slots. In the first time slot, the transmitting end _Sk sends the data _sk to the relay R _m , and then the relay R _m receives the input signal using its receiving communication channel, and in the second time slot sends the forwarding signal y _rm to The corresponding receiving end D _k , the eavesdropping user steals the secret data at this time. The received signals at the relay R _m , the receiving end D _k and the eavesdropping user can be expressed as follows:

是中继R_m处的接收信号；

是接收端D_k处的接收信号；y_e∈C^Ne×1是窃听用户的接收信号；

是发射端S_k与中继R_m之间的通信信道系数矩阵；

是中继R_m与接收端D_k之间的通信信道系数矩阵；

是中继R_m与窃听用户之间的通信信道系数矩阵；

是在发射端S_k的发射信号S_k；

和

是在中继R_m、接收端D_k和窃听用户的加性高斯白噪声，其均值为零方差分别为

和

in,

is the received signal at the relay R _m ;

is the received signal at the receiving end D _k ; y _e ∈ C ^Ne×1 is the received signal of the eavesdropping user;

is the communication channel coefficient matrix between the transmitter _Sk and the relay _Rm ;

is the communication channel coefficient _matrix between the relay _Rm and the receiver Dk;

is the communication channel coefficient matrix between the relay R _m and the eavesdropping user;

is the transmitted signal _{Sk at the transmitting end Sk ;}

and

is the additive white Gaussian noise at the relay R _m , the receiving end D _k and the eavesdropping user, whose mean is zero variance, respectively

and

In order to minimize the overall mean square error MSE of the receiver to realize secure communication, under the constraints of the transmit power of the transmitter and the relay, the transmit precoding matrix, the relay coding matrix and the receive filter matrix are jointly designed to optimize and solve the destination matrix. Specifically, before sending the data _sk , the data _sk sent by the transmitting end _Sk is encoded by using the sending precoding matrix U _k . Likewise, the data y _rm sent by the relay R _m is encoded using the relay coding matrix V _m . Then in the relay R _m , the received signals of the receiver D _k and the eavesdropping user can be re-expressed as:

The linear receiving filter matrix W _k is used to process the received signal of the receiving end D _k , and at the same time, the eavesdropping user will also use the filtering matrix _{We, k} to process the eavesdropping user's own received signal. Therefore, the measurement values of the data _sk by the receiver D _k and the eavesdropping user can be expressed as:

故从公式(7)可以得到在接收端D_k对数据s_k信号的均方误差MSE_k为：Wherein, W _k and _We,k are the receiving filter matrices of N _k ×T _k and N _e ×T _k respectively. Assume that the covariance matrix of the data _sk signal transmitted by the transmitter _Sk is

Therefore, from formula (7), it can be obtained that the mean square error MSE _k of the data _sk signal at the receiving end D _k is:

Similarly, the mean square error MSE _{e of} the eavesdropping user on the data s _k signal can be obtained, where k is:

The transmit power limit at the transmitter and relay can be expressed as:

Among them, P _sk and P _rm represent the maximum transmit power at the transmitting end _Sk and the relay R _m .

In the presence of eavesdropping users, the signal from the transmitter may leak to the eavesdropper. Considering the worst case, it is assumed that the eavesdropper can compute the linear receive matrix _We,k to minimize its own mean square error MSE _,k , and that it knows all the channel state information. Therefore, it is necessary to design the optimal transmit precoding matrix {U _k }, relay coding matrix {V _m } and receive filtering matrix {W _k } to minimize the total mean square error MSE of all receivers, and keep MSE _{e, k} Above a given threshold ε _k (k=1, . . . , K), the transmission power constraints of the transmitter and the relay are satisfied at the same time.

According to the characteristics of the objective function, the transmit precoding matrix, relay coding matrix, and reception filtering matrix are jointly designed to reduce the total mean square error MSE of all legal receivers and make the mean square error MSE _e,k of eavesdropping users within a given value. The predetermined threshold εk ( _k =1, ....., K) ensures the physical layer security of multi-hop broadband power line communication, and ensures the safe transmission of data between the mobile terminal in the station area and the electric energy meter.

6 is a flow chart of steps for optimizing and solving the objective function of the method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

As shown in FIG. 6, in an embodiment of the present invention, the step of optimizing and solving the objective function according to the iterative distributed algorithm includes:

S41. Set initial values for the matrix variables of the transmit precoding matrix and the relay coding matrix, and use the iterative distributed algorithm to calculate the optimal linear matrix of the reception filter matrix;

S42. according to the objective function, solve and obtain the optimized reception filter matrix of the eavesdropping user;

S43. Based on the optimal linear matrix, the optimized reception filter matrix, and the relay coding matrix obtained iteratively in the step S41, calculate the optimized transmit precoding matrix by using the iterative distributed algorithm;

S44. Based on the optimal linear matrix, the optimized reception filter matrix, and the optimized transmit precoding matrix, calculate and obtain the optimized relay coding matrix by using the iterative distributed algorithm.

Since there are multiple matrix variables in formula (13), an iterative distributed algorithm is used to obtain the optimal destination matrix of the transmit precoding matrix, the relay coding matrix and the receive filtering matrix. This iterative distributed algorithm will calculate another matrix variable from the two matrix variables obtained in the previous iteration, and loop in turn. The objective function can be represented by the total mean square error TMSE, the formula is as follows:

It should be noted that, in the first iterative calculation of the transmit precoding matrix, the relay coding matrix and the receive filter matrix using an iterative distributed algorithm, the initial values of {U _k } and {V _m } are set first, and then { The optimal solution of W _k }. Then, in the next iteration, we use the {U _k } and {V _m } obtained in the previous iteration to calculate the optimal {W _k }.

It can be seen from Equation (13) of the objective function that {W _k } and {W _{e, k} } are independent of the transmit power constraints of the transmitter and relay. Through the linear MMSE receiver, we can obtain the optimal linear receiving matrix {W _k }, {W _{e, k} } which minimizes the total mean square error MSE at the receiver. The formula is:

Similarly, the formula of {W _{e, k} } is:

After solving the transmit precoding matrix {U _k }, specifically, after obtaining the receive filtering matrices {W _k } and {W _e,k } according to formulas (15) and (16), it can be obtained according to {W _k }, { We _{e, k} } and {V _m } obtained in the previous iteration are solved by an iterative distributed algorithm to obtain the transmit precoding matrix {U _k } of this iteration. For further analysis, the TMSE of formula (14) can be specifically expressed as:

公式(17)可以简化为：definition

Equation (17) can be simplified to:

对公式(18)进行简化为：definition

Equation (18) is simplified to:

且γ与矩阵变量{U_k}无关,因此可以将它看做一个常量。定义

于是公式(19)可以进一步表示为:in

And γ has nothing to do with the matrix variable {U _k }, so it can be regarded as a constant. definition

So formula (19) can be further expressed as:

In order to simplify the above solution process, the conversion formula introduced as follows is as follows:

tr(A ^H B) = (vec(A)) ^H vec(B),

和

其中

公式(20)可以替换为：definition

and

in

Equation (20) can be replaced by:

TMSE=u ^H ωu-ψu-u ^H ψ ^H +γ (21)

in

Similarly, the mean square error MSE _e,k of the eavesdropping user can be expressed as:

和

in,

and

在发射端的功率限制情况下，公式(11)可以表示为：because

In the case of power limitation at the transmitter, formula (11) can be expressed as:

Equation (23) can be simplified to:

u ^H ρu≤P _sk ,k=1,…,K (24)

in

From formulas (21), (22) and (24), the optimized formula to obtain the transmit precoding matrix {U _k } can be expressed as:

The optimization formula (25) of the transmit precoding matrix {U _k } is a quadratic constrained quadratic programming problem. Compared with the objective function formula (13), the optimization formula (25) can be obtained through the CVX of the MATLAB toolbox. .

For the solution optimization formula of the relay coding matrix {V _m }, specifically, since {W _k }, {W _{e, k} } and {U _k } have been obtained after the optimization above, the total mean square of the receiving end has been obtained. The error TMSE can be expressed as:

in,

于是对公式(26)的接收端的总均方误差TMSE简化为：Definition, V=bd(V ₁ ,V ₂ ,...,V _M ),

So the total mean square error TMSE at the receiving end of formula (26) is simplified to:

Define v=vec(V), then formula (27) can be further simplified as:

TMSE=v ^H Ωv-Ov-v ^H O ^H +v ^H μv+β (28)

in,

Similarly, the mean square error MSE _e,k of the eavesdropping user can be expressed as:

in,

和

其中，

在中继的功率限制可以表示为：because

and

in,

The power limit at the relay can be expressed as:

v ^H λv≤P _rm ,m=1,...,M (30)

in,

From equations (28), (29) and (30), the optimized formula of the relay coding matrix {V _m } can be expressed as:

Among them, the optimization formula (31) of the relay coding matrix {V _m } is a quadratic constrained quadratic programming problem. Compared with the formula (13) problem of the objective function, the optimization formula (31) can be obtained through the CVX of the MATLAB toolbox. beg.

FIG. 7 is a framework diagram of steps for iterative distributed algorithm calculation of the method for secure multi-hop data transmission based on power line communication according to an embodiment of the present invention.

In an embodiment of the present invention, the computing step according to the iterative distributed algorithm includes:

和

S01. Initialize, set the iteration counter n=0, the mean square error TMSE ⁽ⁿ⁾ =0 of the receiving end, the matrix variables of the transmit precoding matrix and the relay coding matrix are set to initial value

and

和所述中继编码矩阵

计算得到所述窃听用户的接收滤波矩阵

和所述接收滤波矩阵

S02. the transmit precoding matrix obtained according to the objective function

and the relay coding matrix

Calculate the receiving filter matrix of the eavesdropping user

and the receive filter matrix

与

和

对所述目标函数进行优化，得到更新后的发射预编码矩阵

S03. Iteratively obtained according to the step S02

and

and

Optimizing the objective function to obtain an updated transmit precoding matrix

和

对所述目标函数进行优化，更新得到

并计算所述接收端的均方误差TMSE⁽ⁿ⁺¹⁾；S04. According to the obtained

and

The objective function is optimized and updated to get

And calculate the mean square error TMSE ⁽ⁿ⁺¹⁾ of the described receiving end;

S05. If TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ ≤ ξ, end the iterative distributed algorithm calculation; if TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ >ξ, n=n+1, execute the above Step S02;

Among them, ξ is the numerical difference between the given two iterations before and after.

It should be noted that the iterative process of the transmit precoding matrix {U _k }, the relay coding matrix {V _m } and the receive filtering matrix {W _k } is performed according to the iterative distributed algorithm, where n represents the nth iteration.

In an embodiment of the present invention, the communication rate of the eavesdropping user and the receiving end of the legitimate user is calculated according to the optimal linear matrix, the optimized relay coding matrix and the optimized transmit precoding matrix, and according to The following formula is solved to obtain the safe rate of data transmission through the multi-hop broadband power line at the receiving end of the legitimate user, and the safe rate is greater than 0; the formula of the safe rate is:

RateD _k =max(0, comD _k )-max(0, comE), k=1, ...... k

Wherein, comD _k is the communication rate of the receiving end of the legitimate user, and comE is the communication rate of the eavesdropping user.

It should be noted that, according to Shannon's theory, secure communication can be achieved only when the secure rate is greater than 0. The communication rate between _Dk at the receiving end and the eavesdropping user can be expressed as:

The above is a multi-hop data security transmission method based on power line communication between the mobile terminal in the station area and the electric energy meter based on the distributed overall mean square error MSE minimization. According to the above theoretical principles, the physical layer of the multi-hop broadband power line communication system can finally be realized. Safety.

FIG. 8 is a change trend diagram of the security rate and the communication rate with the signal-to-noise ratio of the multi-hop data security transmission method based on the power line communication according to the embodiment of the present invention.

As shown in Fig. 8, the number of channels of all communication nodes is 3. Compared with the traditional method, it can be seen from Fig. 8 that the proposed algorithm can ensure that the safety rate increases with the increase of the signal-to-noise ratio (SNR), and the three The communication rates of the links are close, the situation of the safe rate is similar, and there is little difference between the three legitimate users. It can be seen from Figure 8 that the realized security rate is lower than the communication rate, because the purpose matrix calculated by the iterative distributed algorithm will sacrifice part of the communication rate in order to realize the security of data transmission.

FIG. 9 is a convergence diagram of the iterative distribution algorithm of the multi-hop data secure transmission method based on power line communication according to an embodiment of the present invention.

According to K=3, 4, 5, M=3 and P _Sk =P _rm =20dB, the number of channels of all communication nodes is 3. As shown in Figure 9, it can be concluded that TMSE gradually decreases with the increase of the number of iterations until convergence. Specifically, TMSE always converges within the range of 2 to 4 iterations. In addition, as the number of legal transceiver pairs increases, the convergence speed of the algorithm decreases, and TMSE increases. This is because more legitimate transceiver pairs increase. This reduces the system complexity and the interference between each legal transceiver pair, resulting in more iterations to achieve convergence and an increase in TMSE.

Embodiment 2:

FIG. 10 is a frame diagram of a multi-hop data security transmission device based on power line communication according to an embodiment of the present invention.

As shown in FIG. 10 , an embodiment of the present invention provides a multi-hop data security transmission device based on power line communication, which is applied to communication data transmission between a mobile terminal in a station area and an electric energy meter, including:

The actual channel model unit 101 is used for obtaining channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and constructing a channel transfer function corresponding to each communication channel according to each communication parameter, and each communication parameter is combined with the MK model Build the actual channel model for each channel transfer function;

The power line communication system model unit 102 is used for establishing a power line communication system model according to the actual channel model;

establishing an objective function unit 103 for inputting the joint transceiver matrix into the power line communication system model to obtain an objective function;

The computing unit 104 is configured to use an iterative distributed algorithm to optimize and solve the problem according to the objective function, so as to obtain the safe rate of multi-hop data safe transmission on the power line communication system model.

It should be noted that the communication parameters, the MK model, the actual channel model, the power line communication system model, the joint transceiver matrix, the objective function and the solution to the safe rate have been described in detail in the embodiments, and will not be described in this embodiment.

A multi-hop data security transmission device based on power line communication provided by the present invention constructs an actual channel model through an actual channel model unit, uses an objective function establishment unit to input the joint transceiver matrix into the power line communication system model to obtain an objective function, and then uses the calculation unit to obtain an objective function based on The objective function is optimized by an iterative distributed algorithm, and the secure rate of multi-hop data secure transmission is obtained by solving, so that the power line can transmit data at a secure rate, ensure secure communication, and prevent eavesdropping users from stealing data. The technical problems in the prior art that the security of data transmission in the multi-hop broadband power line communication system is low and the communication data in the power line communication system is easy to be stolen are solved.

Embodiment three:

An embodiment of the present invention provides a device, including a processor and a memory;

the memory for storing program codes and transmitting the program codes to the processor;

The processor is configured to execute the above-mentioned multi-hop data security transmission method based on power line communication according to the instructions in the program code.

It should be noted that the processor is configured to execute the steps in the above-mentioned embodiment of the method for secure multi-hop data transmission based on power line communication according to the instructions in the program code, such as steps S1 to S4 shown in FIG. 1 . Alternatively, when the processor executes the computer program, the functions of the modules/units in the foregoing device embodiments, for example, the functions of the units 101 to 104 shown in FIG. 10 , are implemented.

Exemplarily, a computer program may be divided into one or more modules/units, and the one or more modules/units are stored in a memory and executed by a processor to complete the present application. One or more modules/units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device.

The terminal device may be a computing device such as a desktop computer, a notebook, a palmtop computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that it does not constitute a limitation on the terminal device, and may include more or less components than the one shown, or combine some components, or different components, for example, the terminal device may also include input and output devices, Network access equipment, bus, etc.

The processor may be a central processing unit (Central Processing Unit, CPU), or other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf processors Programmable Gate Array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory may be an internal storage unit of the terminal device, such as a hard disk or memory of the terminal device. The memory may also be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash memory card (Flash Card) and the like equipped on the terminal device. Further, the memory may also include both an internal storage unit of the terminal device and an external storage device. The memory is used to store computer programs and other programs and data required by the terminal device. The memory may also be used to temporarily store data that has been or will be output.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above may refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions for causing a device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes .

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: The technical solutions described in the embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (9)

1. a multi-hop data security transmission method based on power line communication, applied to the communication data transmission between the mobile terminal and the electric energy meter in the station area, is characterized in that, comprises the following steps: S1. Obtain the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and construct a channel transfer function corresponding to each of the communication channels according to each of the communication parameters. Each of the communication parameters is combined with the MK model. each of the channel transfer functions constructs an actual channel model; S2. Establish a power line communication system model according to the actual channel model; S3. Input the joint transceiver matrix into the power line communication system model to obtain the objective function; S4. adopting an iterative distributed algorithm to optimize and solve the objective function to obtain a safe rate of multi-hop data safe transmission on the power line communication system model; The joint transceiver matrix includes a transmission precoding matrix, a relay coding matrix and a reception filtering matrix; the objective function includes the constraints of each transmission power, the number of communication channels, and the constraint on the mean square error of the eavesdropping user. and the transmission power constraint of the interrupt side, the objective function is:

st: MSE _{e, k ≥ ε k}

Wherein, K is a natural number not less than 1, {U _k } is the transmit precoding matrix, {V _m } is the relay coding matrix, {W _k } is the receiving filter matrix, {W _e,k } is the reception filter matrix of the eavesdropping user, MSE _k is the mean square error of the receiving end to the data transmitted on the multi-hop broadband power line, MSE _{e, k} is the mean square error of the eavesdropping user to the transmitted data,

is the transmit power of the transmitter,

is the transmitting power of the interrupted end, P _sk is the maximum transmitting power of the transmitting end, P _rm is the maximum transmitting power of the interrupting end, ε _k is the minimum value of MSE _e,k . 2. The method for secure multi-hop data transmission based on power line communication according to claim 1, wherein the communication parameters include the number of paths of each of the communication channels, the transmission distance of the paths, the signal frequency and the communication node; wherein , the communication node can be used to eavesdrop on the user to steal the transmission data on the communication channel. 3. the multi-hop data security transmission method based on power line communication according to claim 2, is characterized in that, according to following formula as the described actual channel model of multi-hop broadband power line:

Among them, i is the number of the path, _gi is the weighting coefficient of each path and the value is a natural number not greater than 1, A(f, d _i ) is the attenuation coefficient of the communication channel, α ₀ , α ₁ and k are all is the attenuation parameter, k is 0.5 to 1, d _i is the transmission distance of the i-th path, and τ _i is the delay on path i

c ₀ is the speed of light, and ε _r is the dielectric constant of the multi-hop broadband power line. 4. The multi-hop data security transmission method based on power line communication according to claim 2, wherein the power line communication system model comprises a transmitter, a relay and a receiver, and based on additive white Gaussian noise, the The mean value of the communication node receiving the data is zero and the variance σ ² is processed to obtain the channel matrix of the link between the transmitting end, the relay and the receiving end. 5. The multi-hop data security transmission method based on power line communication according to claim 1, wherein the step of optimizing and solving the objective function according to the iterative distributed algorithm comprises: S41. Set initial values for the matrix variables of the transmit precoding matrix and the relay coding matrix, and use the iterative distributed algorithm to calculate the optimal linear matrix of the reception filter matrix; S42. according to the objective function, solve and obtain the optimized reception filter matrix of the eavesdropping user; S43. Based on the optimal linear matrix, the optimized reception filter matrix, and the relay coding matrix obtained iteratively in the step S41, calculate the optimized transmit precoding matrix by using the iterative distributed algorithm; S44. Based on the optimal linear matrix, the optimized reception filter matrix, and the optimized transmit precoding matrix, calculate and obtain the optimized relay coding matrix by using the iterative distributed algorithm. 6. The multi-hop data security transmission method based on power line communication according to claim 5, wherein the calculation step according to the iterative distributed algorithm comprises: S01. Initialize, set the iteration counter n=0, the mean square error TMSE ⁽ⁿ⁾ =0 of the receiving end, the matrix variables of the transmit precoding matrix and the relay coding matrix are set to initial value

and

S02. the transmit precoding matrix obtained according to the objective function

and the relay coding matrix

Calculate the receiving filter matrix of the eavesdropping user

and the receive filter matrix

S03. Iteratively obtained according to the step S02

and

and

Optimizing the objective function to obtain an updated transmit precoding matrix

S04. According to the obtained

and

The objective function is optimized and updated to get

And calculate the mean square error TMSE ⁽ⁿ⁺¹⁾ of the described receiving end; S05. If TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ ≤ ξ, end the iterative distributed algorithm calculation; if TMSE ^{(n+1) -} TMSE ⁽ⁿ⁾ >ξ, n=n+1, execute the above Step S02; Among them, ξ is the numerical difference between the given two iterations before and after. 7. The multi-hop data security transmission method based on power line communication according to claim 5, wherein, according to the optimal linear matrix, the optimized relay coding matrix and the optimized transmit precoding Matrix solves the communication rate of the eavesdropping user and the legitimate user receiving end, and obtains the security rate of the legitimate user receiving end through the multi-hop broadband power line to transmit data according to the following formula, and the security rate is greater than 0; the formula of the security rate is : RateD _k =max(0, comD _k )-max(0, comE), k=1, ...... k Wherein, comD _k is the communication rate of the receiving end of the legitimate user, and comE is the communication rate of the eavesdropping user. 8. A multi-hop data security transmission device based on power line communication, applied to the communication data transmission between the mobile terminal and the electric energy meter in the station area, is characterized in that, comprising: The actual channel model unit is used to construct a channel transfer function corresponding to each of the communication channels according to the channel state information and communication parameters of each communication channel on the multi-hop broadband power line, and each of the communication channels. The communication parameters are combined with the MK model to construct an actual channel model for each of the channel transfer functions; a power line communication system model unit, configured to establish a power line communication system model according to the actual channel model; establishing an objective function unit for inputting the joint transceiver matrix into the power line communication system model to obtain an objective function; a computing unit, configured to use an iterative distributed algorithm to optimize and solve according to the objective function, and obtain a safe rate of multi-hop data safe transmission on the power line communication system model; The joint transceiver matrix includes a transmission precoding matrix, a relay coding matrix and a reception filtering matrix; the objective function includes the constraints of each transmission power, the number of communication channels, and the constraint on the mean square error of the eavesdropping user. and the transmission power constraint of the interrupt side, the objective function is:

st: MSE _{e, k ≥ ε k}

Wherein, K is a natural number not less than 1, {U _k } is the transmit precoding matrix, {V _m } is the relay coding matrix, {W _k } is the receiving filter matrix, {W _e,k } is the reception filter matrix of the eavesdropping user, MSE _k is the mean square error of the receiving end to the data transmitted on the multi-hop broadband power line, MSE _{e, k} is the mean square error of the eavesdropping user to the transmitted data,

is the transmit power of the transmitter,

is the transmitting power of the interrupted end, P _sk is the maximum transmitting power of the transmitting end, P _rm is the maximum transmitting power of the interrupting end, ε _k is the minimum value of MSE _e,k . 9. A multi-hop data security transmission device based on power line communication, characterized in that it comprises a processor and a memory; the memory for storing program codes and transmitting the program codes to the processor; The processor is configured to execute the multi-hop data secure transmission method based on power line communication according to any one of claims 1-7 according to the instructions in the program code.

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