Physical layer security optimization method and equipment for full-duplex multi-carrier power line communication system

Abstract

The invention relates to an electric power communication system optimization technology, in particular to a physical layer security optimization method and equipment for a full-duplex multicarrier power line communication system, and the method combines a full-duplex technology and a time domain artificial noise auxiliary security strategy to construct a multicarrier power line communication system model with a relay; generating a safety rate maximization problem, designing a set of convex approximation method, and performing conversion and simplification of a non-convex optimization problem; designing an iterative solution algorithm, and jointly optimizing the confidential data of the source node, the confidential data of the relay node and the artificial noise power distribution matrix; and optimizing the physical layer safety performance of the full-duplex multi-carrier power line communication system based on the solved power distribution matrix. According to the communication scheme and the solved power distribution vector, the safety performance of the power line communication system is optimized, the limitation of the number of power transmission cables in the power line communication system is avoided, the safety rate maximization of the total transmitting power domain can be realized, and the technical problem that data in an existing multi-hop power line communication system is prone to leakage is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power communication system optimization, and in particular relates to a physical layer security optimization method and device for a full-duplex multi-carrier power line communication system. Background Art

[0002] Power line communication (PLC), with its advantages of requiring no additional wiring, low cost, and wide coverage, has become the most promising communication method for smart grid deployment. With the widespread adoption of PLC technology, communication security has become a major challenge to ensure safe grid operation and user privacy. Physical layer security leverages the uniqueness and randomness of the channel to ensure secure transmission, fundamentally enabling secure communication and improving the security rate of power communication systems. Therefore, research on physical layer security design and optimization methods for PLC systems is crucial.

[0003] Beamforming and cooperative jamming can improve the physical layer security of power line communications. Multiple-input, multiple-output (MIMO) technology allows for beamforming of confidential data, increasing security rates. However, the limited number of cables in power transmission lines (up to four) limits the security gains of MIMO beamforming. Using external relays to transmit jamming signals to degrade the quality of the received signal for eavesdroppers can also enhance security, but external relays present certain synchronization and security issues.

[0004] Designing artificial noise in the transmitted signal can ensure secure transmission at the physical layer, but traditional artificial noise coding also requires spatial freedom and is constrained by the limited cables of the power system. Designing time-domain zero-forcing artificial noise based on the freedom brought by the cyclic prefix in orthogonal frequency division multiplexing technology is not constrained by spatial freedom. However, this method has only been studied in point-to-point communication systems, and artificial noise technology is not suitable for low-transmit power scenarios.

[0005] In addition, full-duplex technology allows simultaneous bidirectional data transmission on the same frequency, with the potential to simultaneously improve spectrum efficiency and security rate. However, due to the limitation of self-interference at high transmit power, the performance gains provided by full-duplex technology are only concentrated in the low transmit power domain and are not suitable for high transmit power scenarios.

[0006] Therefore, designing communication methods and physical layer security strategies for power line communication systems, and optimizing resources in complex scenarios, especially multi-hop systems, to improve the power line communication security rate in the full transmission power domain, are important issues in this field that have both application value and technical challenges. Summary of the Invention

[0007] The present invention provides a physical layer security optimization method and device for a full-duplex multi-carrier power line communication system, which is used to address the defects in the existing technology that artificial noise technology is not suitable for low-transmission power scenarios and full-duplex technology is not suitable for high-transmission power scenarios. It realizes physical layer security transmission assisted by time-domain artificial noise, optimizes the power allocation scheme at the source node and relay, and maximizes the system's safe rate.

[0008] The present invention provides a physical layer security optimization method for a full-duplex multi-carrier power line communication system, comprising the following steps: Step 1. Combine full-duplex technology and time-domain artificial noise-assisted security strategy to build a multi-carrier power line communication system model with relay; Step 2. Generate a safe rate maximization problem and use a convex approximation method to transform and simplify the non-convex optimization problem. Step 3. Use an iterative solution algorithm to jointly optimize the source node confidential data, relay node confidential data, and artificial noise power allocation matrix; Step 4. Based on the solved power allocation matrix, optimize the physical layer security performance of the full-duplex multi-carrier power line communication system.

[0009] According to the physical layer security optimization method for a full-duplex multi-carrier power line communication system provided by the present invention, in the power line communication system model of step 1, the source node Alice communicates with the destination node Bob through a relay R. During this process, an eavesdropper Eve steals confidential data from the power line channel. Each node communicates based on OFDM multi-carrier modulation. The decoding and forwarding relay in the present invention is full-duplex, so there will be residual self-interference signals. To interfere with eavesdroppers, based on the cyclic prefix freedom and Fourier transform technology, the relay inserts time-domain zero-forcing artificial noise when forwarding frequency-domain confidential data. The received signals of each node are respectively expressed as:

[0010]

[0011]

[0012] in The signals are received at the relay, destination node, and eavesdropper respectively. Confidential data sent by the source node, Decode the forwarded confidential data for the relay, is the time domain zero-forcing artificial noise sent by the relay, for The zero-forcing space of can be obtained by singular value decomposition (SVD), are the additive background noise encountered when receiving the signal; is the normalized discrete Fourier transform matrix, for The conjugate transpose matrix of is also equal to its inverse matrix, Respectively represent the cyclic prefix removal matrix and the cyclic prefix insertion matrix; is the full-duplex self-interference coefficient, and the self-interference channel matrix of the full-duplex relay is recorded as , the time domain power line channel matrices from source node to relay, relay to destination node, and relay to eavesdropper are .

[0013] According to the physical layer security optimization method for a full-duplex multi-carrier power line communication system provided by the present invention, the specific steps of generating a security rate maximization problem in step 2 and designing a set of convex approximation methods to convert and simplify the non-convex optimization problem are as follows: Step 2.1. Under the total system power constraint, construct an optimization problem with the source and relay node confidential data and the artificial noise power allocation matrix as optimization variables and the security rate as the optimization objective. Step 2.2. Analyze the non-convex optimization problem and adopt a suboptimal optimization strategy for the artificial noise power allocation matrix; Step 2.3. By introducing auxiliary variables, Matrix function approximation theory provides convex approximation to non-convex terms in the objective function; Step 2.4. Introduce the necessary conditions for the optimal solution and prove them, and transform and simplify the non-convex terms in the constraints.

[0014] According to the physical layer security optimization method of the full-duplex multi-carrier power line communication system provided by the present invention, based on the system model, the security rate maximization problem is constructed:

[0015]

[0016]

[0017]

[0018]

[0019] Among them, the optimization variables They are respectively the confidential data of the source node in multi-carrier transmission , relay confidential data , relay artificial noise The power allocation matrix, are the total power of transmitted signals of the source node and relay respectively; are the signal-to-interference-and-noise ratio (SINR) at the relay, destination node, and eavesdropper, respectively. ,remember are the additive background noise power, Represents a diagonal matrix operation.

[0020] According to the physical layer security optimization method for a full-duplex multi-carrier power line communication system provided by the present invention, the suboptimal optimization strategy for the artificial noise power allocation matrix is:

[0021] That is, the power allocation matrix for confidential data The artificial noise power distribution matrix is obtained by optimization. The vector part is approximated by average distribution, and only its power distribution coefficient is optimized .

[0022] According to the physical layer security optimization method of the full-duplex multi-carrier power line communication system provided by the present invention, by introducing auxiliary variables, The implementation of matrix function approximation theory for convex approximation of non-convex terms in the objective function includes: Expand the non-convex terms in the objective function regarding the eavesdropping rate:

[0023] make , introduced as follows Matrix function approximation theorem is used for conversion:

[0024] Introducing auxiliary variables Transform the legal rate term: .

[0025] According to the physical layer security optimization method of the full-duplex multi-carrier power line communication system provided by the present invention, the necessary conditions for the optimal solution are introduced to transform the constraint conditions: for the decoding and forwarding full-duplex relay system, when the SINR of the relay node and the destination node are equal, the optimal solution to the security rate maximization problem is obtained, and accordingly get:

[0026] At this moment Can be achieved through Representing it is equivalent to reducing the optimization variables and simplifying the optimization problem to:

[0027] .

[0028] According to the physical layer security optimization method for a full-duplex multi-carrier power line communication system provided by the present invention, the iterative solution algorithm is used in step 3 to jointly optimize the source node confidential data, the relay node confidential data and the artificial noise power allocation matrix, including the following steps: An iterative optimization algorithm is designed through one-dimensional search and block coordinate descent methods. The non-convex problem is converted into a directly solvable convex subproblem, and the power allocation matrix is jointly optimized. The power joint optimization algorithm for maximizing the safe rate is as follows: Step 3.1. Initialize to average power allocation; Step 3.2. Calculate the channel gain of each subcarrier, perform sequential subcarrier pairing for the two-hop link, and input channel state information

[0029] ; Step 3.3. Calculate the optimal value of auxiliary variables based on the power allocation matrix ; Step 3.4. Fixation , solve the neutron optimization problem in step 2.4, and get ; Step 3.5. Repeat the first two steps until convergence, and record the artificial noise power as Maximum safe speed under end Step 3.6. Select the maximum safe rate With this time As a power distribution scheme at relays; Step 3.7. Based on the necessary conditions for the optimal solution , substitute and Calculate the power allocation scheme of the source node .

[0030] The present invention also provides an electronic device, comprising a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the full-duplex multi-carrier power line communication system physical layer security optimization method.

[0031] The present invention also provides a computer-readable storage medium having a computer program / instruction stored thereon. When the computer program / instruction is executed by a processor, the steps of the physical layer security optimization method of the full-duplex multi-carrier power line communication system are implemented.

[0032] Compared with the prior art, the present invention has the following beneficial effects: 1. The security strategy has a wider application scope: The artificial noise in the present invention is a time-domain zero-forcing artificial noise based on the OFDM cyclic prefix freedom. Compared with the security solutions based on multiple-input multiple-output technology and multi-antenna array gain, it has a wider application scope and is not limited by the number of power cables, especially in single-phase power line systems.

[0033] 2. Greater practicality in complex scenarios: Due to the increasing requirements for transmission distance and communication rate, actual communication systems have transformed into complex multi-hop and multi-carrier systems. The present invention is based on the physical layer security optimization of multi-carrier relay communication systems. Compared with traditional single-hop or single-carrier system research, it is closer to complex application scenarios in reality and has greater practicality.

[0034] 3. The system can achieve a higher security rate: The present invention constructs a security rate maximization problem and designs an iterative solution algorithm through a convex approximation method, jointly optimizing the power allocation matrix of confidential information and artificial noise. It can combine the security gain of the low transmission power domain of full-duplex and the security gain of the high transmission power domain of artificial noise, and achieve a higher security rate under different transmission power conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a flow chart of a physical layer security optimization method for a full-duplex multi-carrier power line communication system provided by an embodiment of the present invention; Figure 2 This is a model diagram of a power line communication system provided by an embodiment of the present invention; Figure 3 This is a graph showing the relationship between the average security rate of the method of the present invention and the non-AN solution and the non-full-duplex solution as a function of the system transmit power, provided by an embodiment of the present invention; Figure 4 1. A graph showing a relationship between the average safety rate and the system transmit power in the power joint optimization algorithm and the equal power allocation scheme in the method of the present invention, provided by an embodiment of the present invention; Figure 5 This is a graph showing the relationship between the average security rate and system transmit power under different channel noise environments and self-interference levels provided by an embodiment of the present invention; Figure 6 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0038] This embodiment combines full-duplex, multi-carrier, and relay transmission technologies to design a power line communication system. It also designs a physical layer security transmission strategy assisted by time-domain artificial noise, optimizes the subcarrier pairing scheme and power allocation scheme at the source node and relay, and maximizes the system's safe rate.

[0039] like Figure 1 As shown, the physical layer security optimization method of the full-duplex multi-carrier power line communication system includes the following steps: S1, combining full-duplex technology and time-domain artificial noise-assisted security strategy to build a multi-carrier power line communication system model with relay; like Figure 2 As shown, the source node Alice communicates with the destination node Bob through the relay R. In this process, there is an eavesdropper Eve who steals confidential data from the power line channel. Each node communicates based on OFDM multi-carrier modulation. The decoding and forwarding relay in this embodiment is full-duplex, so there will be residual self-interference signals.

[0040] In order to interfere with eavesdroppers, based on the cyclic prefix freedom and Fourier transform technology, the relay will insert time domain zero-forcing artificial noise when forwarding frequency domain confidential data. The relay transmission signal is , i.e. frequency domain confidential data After inverse Fourier transform and cyclic prefix insertion, it becomes the time domain signal to be sent, and zero-forcing artificial noise is added at this time Then send it. The time domain artificial noise channel matrix of the link from R to Bob is , through the zero-forcing design, ,It can ensure that artificial noise does not interfere with the destination node, but only interferes with the eavesdropper, thus ensuring secure transmission, for The forced zero space can be obtained by singular value decomposition SVD:

[0041] Therefore, the received signals of each node are expressed as:

[0042]

[0043]

[0044] in The signals are received at the relay, destination node, and eavesdropper respectively. Confidential data sent by the source node, Decode the forwarded confidential data for the relay, is the time domain zero-forcing artificial noise sent by the relay, are the additive background noise encountered when receiving the signal; is the normalized discrete Fourier transform matrix, for The conjugate transpose matrix of is also equal to its inverse matrix, Respectively represent the cyclic prefix removal matrix and the cyclic prefix insertion matrix; is the full-duplex self-interference coefficient, and the self-interference channel matrix of the full-duplex relay is recorded as , the time domain power line channel matrices from source node to relay, relay to destination node, and relay to eavesdropper are , its specific expression is:

[0045] in, is the time domain impulse response (CIR) of the power line channel, which can be obtained by inverse Fourier transform of the frequency domain channel model. Represents the length of the discrete channel impulse response.

[0046] S2, generate the safety rate maximization problem and design a set of convex approximation methods to transform and simplify the non-convex optimization problem; S2.1, under the constraint of total system power, the optimization problem is constructed with the confidential data of the source node and relay node, the artificial noise power allocation matrix as optimization variables, and the security rate as the optimization target as follows:

[0047]

[0048]

[0049]

[0050]

[0051] Among them, the optimization variables They are respectively the confidential data of the source node in multi-carrier transmission , relay confidential data , relay artificial noise The power allocation matrix, are the total power of transmitted signals of the source node and relay respectively; are the signal-to-interference-and-noise ratio (SINR) at the relay, destination node, and eavesdropper, respectively. ,remember are the additive background noise power, Represents a diagonal matrix operation.

[0052] S2.2, analyze the non-convex optimization problem and adopt a suboptimal optimization strategy for the artificial noise power allocation matrix:

[0053] That is, the power allocation matrix for confidential data The artificial noise power distribution matrix is obtained by optimization. The vector part is approximated by average distribution, and only its power distribution coefficient is optimized .

[0054] This is because the matrix entries containing the optimization variables are diagonalized. It is difficult to optimize and solve, and this operation is only related to the artificial noise power distribution matrix, whose dimension is ,The dimension of the power allocation matrix of frequency domain confidential data is , in OFDM systems Relative to is very small, which means that the suboptimal power allocation for artificial noise has little impact on the overall security rate maximization problem. At this time, the SINR expression of each receiving end is simplified to:

[0055] in:

[0056]

[0057] S2.3, by introducing auxiliary variables, Matrix function approximation theory provides convex approximation to non-convex terms in the objective function; First, expand the non-convex term of the eavesdropping rate in the objective function:

[0058] make , introduced as follows Matrix function approximation theorem is used for conversion:

[0059] Further introduction of auxiliary variables Transform the legal rate term:

[0060] Based on this, the optimization problem can be reformulated as:

[0061]

[0062] S2.4, introduce and prove the necessary conditions for the optimal solution, and transform and simplify the non-convex terms in the constraints; Necessary conditions for an optimal solution: For the decode-and-forward full-duplex relay system in this embodiment, when the SINRs of the relay node and the destination node are equal, an optimal solution can be obtained for the problem of maximizing the security rate.

[0063] Proof: Based on proof by contradiction This optimal solution is necessary to prove the optimal solution. , assuming , there are two situations: (1) There is a subcarrier whose first hop rate is lower than the second hop rate, that is, , then there is another solution ,in For any small positive value, it can be seen that the system constraints are still satisfied when this solution is taken. Substituting it into the SINR expression of each receiving end, we get: reduce, Increase, Reduced due to and Small, so the signal to interference and noise ratio of the legal channel Increases, while the eavesdropper's signal-to-noise ratio decreases, so the system security rate is greater, that is, the power allocation scheme assumed at this time Not the optimal solution; (2) There is a subcarrier whose first hop rate is greater than the second hop rate, that is, , there is another solution ,in is any small positive value, then and unchanged, but Slightly lower due to and is smaller, so we can get unchanged, that is, there is another solution that makes the system security rate unchanged, but the source node consumes power Reduced, then the power distribution scheme assumed at this time It is not the best solution in general, you can choose the appropriate Make ,At this time, the result of maximizing the safety rate remains unchanged, and the system power consumption is reduced.

[0064] In summary, when the optimal solution of the system is obtained, the first-hop signal-to-interference-noise ratio of any subcarrier is neither less than nor greater than its second-hop signal-to-interference-noise ratio, that is, , which is a necessary condition for the optimal solution, so let get:

[0065] At this moment Can be achieved through Representing it is equivalent to reducing the optimization variables, thereby simplifying the optimization problem to:

[0066]

[0067] S3, design an iterative solution algorithm to jointly optimize the source node confidential data, relay node confidential data and artificial noise power allocation matrix; First, we analyze the solvability of the simplified optimization problem: there is a non-convex power constraint in the problem, that is, , but the optimization variables is a scalar, which can be determined by one-dimensional search. It becomes convex when it is determined; there is a non-convex objective function term in the problem , can be iteratively optimized through the block coordinate descent (BCD) idea, when solving The optimal value of Fixed, when optimized Fixed auxiliary variables , by alternately iteratively optimizing the two sub-problems, we can gradually approach the optimal solution of the problem.

[0068] The power allocation matrix is optimized and jointly solved by an iterative solution algorithm. The power joint optimization algorithm designed by the present invention for maximizing the safety rate is as follows:

[0069] The output parameters in the above table can be used to determine the power allocation matrix of confidential information and artificial noise at the source node and relay.

[0070] S4, based on the solved power allocation matrix, optimizes the physical layer security performance of the full-duplex multi-carrier power line communication system to maximize the safe rate in the entire transmission power domain.

[0071] The verified safety rates under different transmit powers and different algorithm settings are simulated and calculated using MATLAB and the CVX toolbox. All safety rates are the average safety rates of the subcarriers obtained by averaging 500 experiments. It should be noted that this embodiment uses the measured power line channel parameters in the paper "A Fitting Algorithm for Random Modeling the PLC Channel" published by scholars such as Andrea M. Tonello and Fabio Versolatto for simulation experiments, which is more practical.

[0072] Figure 3 The following are curves showing the change of security rate with transmission power for different communication schemes: method one is a half-duplex relay scheme assisted by time-domain artificial noise, method two is a full-duplex relay scheme without time-domain artificial noise, method three is the full-duplex relay OFDM scheme assisted by time-domain artificial noise proposed in this embodiment, and method four is a general half-duplex relay power line communication system.

[0073] like Figure 3 As shown in the figure, we can get the following from the curve: (1) Compared with half-duplex relay, full-duplex relay can greatly improve the security rate when the transmission power is low, but as the total power increases, the full-duplex self-interference will cause its rate to be limited, so the security gain gradually decreases. When the transmission power is further increased, the security rate of the half-duplex system will surpass it, which proves the superiority of full-duplex technology in improving system performance in the low-power domain; (2) Comparing the half-duplex scheme assisted by time-domain artificial noise with the general half-duplex relay system, it is found that the security rates of the two are close when the transmission power is low, and the time-domain artificial noise will greatly improve the security rate when the transmission power is high. This is because when the transmission power is low, security is mainly achieved by allocating power to confidential data. When the transmission power is high, power is allocated to artificial noise, and its interference and eavesdropping can be reflected. The time domain artificial noise strategy in the full-duplex relay system shows the same effect; (3) The scheme proposed in this embodiment can achieve the best security rate performance in the entire power domain. When the transmission power is low, security gain is provided by full-duplex and confidential data power allocation. When the transmission power is high, the security rate is improved by adding artificial noise. This optimization of the allocation of confidential data and artificial noise power is adaptively obtained through an iterative algorithm, which proves the superiority of the technical solution of the present invention.

[0074] Figure 4The following are security performance comparison curves for different power allocation methods. Method 1 is an equal power method, which evenly distributes power to the confidential data and artificial noise of each subcarrier, and performs subcarrier pairing based on this. Method 2 is the power optimization method in this embodiment. Subcarrier pairing is first performed based on average power allocation, and then a power joint optimization algorithm for maximizing security rate is used to optimize power allocation.

[0075] Figure 4 The comparison of the curves in the figure shows that the joint optimization method is always better than the equal power scheme, which is consistent with the theoretical analysis. At the same time, it can be noted that when the transmission power is a large value, the relative gain of the security rate brought by power optimization will decrease. The reason for this is that when the transmission power is large, more power will be allocated to the artificial noise signal to interfere with the eavesdropper to achieve security. At this time, the optimization part of the confidential data power gradually degenerates into a non-security issue, that is, it is only responsible for maximizing the legal channel capacity. At this time, its power optimization result is very similar to water injection allocation. When the transmission power is large, the result of water injection allocation will gradually approach the average power allocation result, resulting in a gradual decrease in the relative performance gain provided by the joint optimization scheme. This proves the adaptability of the technical solution of the present invention to different scenarios: when the terminal device has strong computing power and high security rate requirements, the proposed power optimization algorithm can be used to achieve higher security performance; when the terminal device has weak computing power and high transmission power, equal power allocation can still achieve a large security rate with low computational complexity.

[0076] Figure 5 The effects of full-duplex self-interference coefficient and power line channel noise intensity on the safe rate are shown.

[0077] Figure 5 The comparison of the curves in the figure shows that when the total transmission power of the multi-carrier system is low, the impact of the increase in the self-interference coefficient is very small. When the transmission power increases, the impact will gradually increase. In this embodiment, multi-carrier modulation is used, so the subcarrier power is small (on average 1 / N of the total power), which can reduce the adverse effects of self-interference. The curve shows that the full-duplex performance upper limit is still not reached when the transmission power is 45dBm. The curve shows that when the power line channel noise is reduced, the system's security rate in the entire transmission power domain will be improved. Although the reduction of the eavesdropper's channel noise will also lead to an increase in the eavesdropping rate, the legitimate channel rate can be increased more through system design and power optimization. This proves that with the development of power line communication systems and channel estimation technologies, the quality of power line channels has improved, and the technical solution in this embodiment will show better security rate performance.

[0078] In summary, the present invention utilizes full-duplex and time-domain artificial noise to jointly participate in the design of system security, and maximizes the security rate by optimizing the power allocation of confidential data and artificial noise in multi-carriers. It is not limited by the number of transmission cables in the power line communication system, and can combine the low transmission power domain security gain of full-duplex and the high transmission power domain security gain of artificial noise to achieve a higher security rate under different transmission power conditions, thereby solving the technical problem of easy data leakage in existing multi-hop power line communication systems.

[0079] Figure 6 An example of a physical structure diagram of an electronic device is shown below. Figure 6 As shown, the electronic device may include: a processor, a communications interface, a memory, and a communications bus, wherein the processor, the communications interface, and the memory communicate with each other via the communications bus. The processor may invoke logic instructions in the memory to execute a method for optimizing physical layer security in a full-duplex multi-carrier power line communication system.

[0080] Furthermore, the logical instructions in the aforementioned memory can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0081] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the full-duplex multi-carrier power line communication system physical layer security optimization method provided by the above methods.

[0082] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0083] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A physical layer security optimization method for a full-duplex multi-carrier power line communication system, characterized in that: The following steps are involved: Step 1. Combine full-duplex technology and time-domain artificial noise-assisted security strategy to build a multi-carrier power line communication system model with relay; Step 2. Generate a safe rate maximization problem and use a convex approximation method to transform and simplify the non-convex optimization problem. Step 3. Use an iterative solution algorithm to jointly optimize the source node confidential data, relay node confidential data, and artificial noise power allocation matrix; Step 4. Based on the solved power allocation matrix, optimize the physical layer security performance of the full-duplex multi-carrier power line communication system.

2. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 1, characterized in that: In the power line communication system model described in step 1, the source node (Alice) communicates with the destination node (Bob) via a relay (R). During this process, an eavesdropper (Eve) could steal confidential data from the power line channel. Each node communicates based on OFDM multi-carrier modulation. The decode-and-forward relay in this invention is full-duplex, resulting in residual self-interference signals. To interfere with eavesdroppers, the relay, based on cyclic prefix freedom and Fourier transform technology, inserts time-domain zero-forcing artificial noise when forwarding frequency-domain confidential data. The received signals at each node are represented as follows: in The signals are received at the relay, destination node, and eavesdropper respectively. Confidential data sent by the source node, Decode the forwarded confidential data for the relay, is the time domain zero-forcing artificial noise sent by the relay, for The zero-forcing space of can be obtained by singular value decomposition (SVD), are the additive background noise encountered when receiving the signal; is the normalized discrete Fourier transform matrix, for The conjugate transpose matrix of is also equal to its inverse matrix, Respectively represent the cyclic prefix removal matrix and the cyclic prefix insertion matrix; is the full-duplex self-interference coefficient, and the self-interference channel matrix of the full-duplex relay is recorded as , the time domain power line channel matrices from source node to relay, relay to destination node, and relay to eavesdropper are .

3. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 1, characterized in that: The specific steps of step 2 are as follows: Step 2.

1. Under the total system power constraint, construct an optimization problem with the source and relay node confidential data and the artificial noise power allocation matrix as optimization variables and the security rate as the optimization objective. Step 2.

2. Analyze the non-convex optimization problem and adopt a suboptimal optimization strategy for the artificial noise power allocation matrix; Step 2.

3. By introducing auxiliary variables, Matrix function approximation theory provides convex approximation to non-convex terms in the objective function; Step 2.

4. Introduce the necessary conditions for the optimal solution and prove them, and transform and simplify the non-convex terms in the constraints.

4. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 3, characterized in that: Based on the system model, construct the safety rate maximization problem: Among them, the optimization variables They are respectively the confidential data of the source node in multi-carrier transmission , relay confidential data , relay artificial noise The power allocation matrix, are the total power of transmitted signals of the source node and relay respectively; are the signal-to-interference-and-noise ratio (SINR) at the relay, destination node, and eavesdropper, respectively. ,remember are the additive background noise power, Represents a diagonal matrix operation.

5. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 3, characterized in that: The suboptimal optimization strategy for the artificial noise power allocation matrix is: That is, the power allocation matrix for confidential data The artificial noise power distribution matrix is obtained by optimization. The vector part is approximated by average distribution, and only its power distribution coefficient is optimized .

6. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 3, characterized in that: The implementation of step 2.3 includes: Expand the non-convex terms in the objective function regarding the eavesdropping rate: make , introduced as follows Matrix function approximation theorem is used for conversion: Introducing auxiliary variables Transform the legal rate term: 。 7. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 3, characterized in that: In step 2.4, the necessary conditions for the optimal solution are introduced to transform the constraints: for the decoding and forwarding full-duplex relay system, when the SINR of the relay node and the destination node are equal, the optimal solution of the security rate maximization problem is obtained. get: At this moment Can be achieved through Representing it is equivalent to reducing the optimization variables and simplifying the optimization problem to: 。 8. The method for optimizing physical layer security of a full-duplex multi-carrier power line communication system according to claim 7, characterized in that: The implementation of step 3 includes the following steps: An iterative optimization algorithm is designed through one-dimensional search and block coordinate descent methods. The non-convex problem is converted into a directly solvable convex subproblem, and the power allocation matrix is jointly optimized. The power joint optimization algorithm for maximizing the safe rate is as follows: Step 3.

1. Initialize to average power allocation; Step 3.

2. Calculate the channel gain of each subcarrier, perform sequential subcarrier pairing for the two-hop link, and input channel state information ； Step 3.

3. Calculate the optimal value of auxiliary variables based on the power allocation matrix ; Step 3.

4. Fixation , solve the neutron optimization problem in step 2.4, and get ; Step 3.

5. Repeat the first two steps until convergence, and record the artificial noise power as Maximum safe speed under end Step 3.

6. Select the maximum safe rate With this time As a power distribution scheme at relays; Step 3.

7. Based on the necessary conditions for the optimal solution , substitute and Calculate the power allocation scheme of the source node .

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory, wherein: The processor executes the computer program to implement the steps of the full-duplex multi-carrier power line communication system physical layer security optimization method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the physical layer security optimization method of the full-duplex multi-carrier power line communication system as claimed in any one of claims 1 to 8 are implemented.

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