A legal eavesdropping method for physical layer security-assisted suspicious ad-hoc communication

Abstract

The present invention discloses a legal eavesdropping method for physical-layer security-assisted suspicious ad-hoc communication, belonging to the field of wireless communication, which includes: establishing an optimization problem model for active eavesdropping interference power allocation in physical-layer security-assisted suspicious ad-hoc communication; transforming the established optimization problem into a two-layer optimization problem with inner and outer nesting, where the outer-layer optimization problem optimizes the relative eavesdropping rate and the inner-layer optimization problem optimizes the interference power allocation; solving the outer-layer optimization problem by the bisection method to obtain the relative eavesdropping rate, and for a given relative eavesdropping rate, solving the inner-layer optimization problem by the Lagrange method to obtain the interference power allocation. The present invention mainly aims at the scenario where suspicious ad-hoc communication terminals use physical-layer security technology for communication. The legal eavesdropper can optimize the interference power allocation to maximize the relative eavesdropping rate of the eavesdropping node, and use active eavesdropping to interfere to reduce the channel quality of the suspicious communication link and greatly improve the eavesdropping performance.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication and relates to a legal eavesdropping method for physical layer security-assisted suspicious ad hoc communication. Background Art

[0002] Wireless communication technology has become a research focus in recent years, and the security issue of wireless ad hoc communication in wireless communication is also a research hotspot.

[0003] In view of the extremely complex wireless ad hoc terminal communication environment, how to ensure reliable eavesdropping of suspicious communication is a research hotspot. Since the physical layer is the bottom layer of communication, it is crucial to implement eavesdropping of suspicious communication from the perspective of the physical layer. Communication eavesdropping and communication security are two aspects of the same thing. Communication security focuses on how to ensure the security of information transmission, while communication eavesdropping focuses on how to eavesdrop on the information transmitted by suspicious communication. Compared with passive eavesdropping of suspicious communication, active eavesdropping can improve the performance of eavesdropping. Therefore, we provide a legal eavesdropping method for physical layer security-assisted suspicious ad hoc communication. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a legal eavesdropping method for physical layer security-assisted suspicious ad hoc communication. When a legal eavesdropper encounters a situation where a suspicious ad hoc communication terminal uses physical layer security technology for secure communication, active eavesdropping is used to interfere so as to reduce the channel quality of the suspicious communication link and improve the eavesdropping performance. Under the requirement of meeting the maximum average power of the eavesdropping node, the relative eavesdropping rate can be maximized.

[0005] To achieve the above purpose, the present invention is implemented by the following technical solutions:

[0006] In the first aspect, the present invention provides a legal eavesdropping method for physical layer security-assisted suspicious ad hoc communication, based on an ad hoc communication system; the ad hoc communication system includes multiple pairs of suspicious ad hoc communication terminals and a full-duplex eavesdropping node; each pair of suspicious ad hoc communication terminals includes a suspicious communication source and a suspicious communication destination; each suspicious communication source transmits suspicious information to the suspicious communication destination based on physical layer security technology, and the eavesdropping node can eavesdrop on the transmission of the suspicious information;

[0007] The legal eavesdropping method maximizes the relative eavesdropping rate of the interfering node by optimizing the interference power allocation of the eavesdropping node, and specifically includes the following steps:

[0008] Step 1: Establish an optimization problem model for the active eavesdropping interference power allocation of physical layer security-assisted suspicious ad hoc communication;

[0009] Step 2: Transform the established optimization problem into a two-layer optimization problem with inner and outer nesting. Among them, the outer-layer optimization problem optimizes the relative listening rate, and the inner-layer optimization problem optimizes the interference power allocation;

[0010] Step 3: Solve the outer-layer optimization problem by the bisection method to obtain the relative listening rate. For a given relative listening rate, solve the inner-layer optimization problem by the Lagrangian method to obtain the interference power allocation, and optimize the relative listening rate and interference power allocation of the monitoring node.

[0011] Based on the first aspect, further, the optimization problem model for establishing the active listening interference power allocation of physical layer security-assisted suspicious ad-hoc communication is:

[0012] P1:

[0013] Constraint C1:

[0014] This problem aims to maximize the relative listening rate of the listening node, where K is the number of suspicious ad-hoc communication terminal pairs; and respectively represent the secrecy information transmission rate of the suspicious ad-hoc communication terminal pair k, the codebook transmission rate of the suspicious ad-hoc communication terminal pair k, the achievable rate of the listening node for the suspicious ad-hoc communication terminal pair k, and the listening rate of the listening node for the suspicious ad-hoc communication terminal pair k; v represents the fading state of the channel; ε represents the expectation over all fading states;

[0015] P k and q k (v) respectively represent the fixed transmission power of the suspicious ad-hoc communication terminal pair k and the interference power of the listening node for the suspicious ad-hoc communication terminal pair k; α k represents the power ratio allocated by the suspicious ad-hoc communication terminal pair k to the secrecy information transmission;

[0016] and respectively represent the channel gain between the transmitter and receiver of the suspicious ad-hoc communication terminal pair k, the channel gain from the listening node to the destination of the suspicious ad-hoc communication terminal pair k, and the channel gain from the source of the suspicious ad-hoc communication terminal pair k to the listening node; ξ is the full-duplex self-interference cancellation coefficient at the listening node; σ 2 is the noise power; Q represents the maximum average transmission power of the listening node;

[0017] Constraint C1 means that the average transmission power of the listening node cannot exceed the maximum average transmission power.

[0018] Based on the first aspect, further, the conversion of the established optimization problem into a two-layer optimization problem with inner and outer nesting specifically includes the following steps:

[0019] Step 2-1: By introducing an auxiliary variable θ to represent the relative listening rate achieved by the listening nodes, rewrite Problem P1 as:

[0020] P2:

[0021] Constraint C2:

[0022] Constraint C1;

[0023] Step 2-2: Reconstruct Problem P2 into a two-layer problem with inner and outer nesting. Among them, the outer-layer optimization problem optimizes θ to obtain the maximum relative listening rate value; the inner-layer optimization problem optimizes q k (ν) under the condition of a given θ, and the problem is modeled as:

[0024] P3:

[0025] Constraint C1.

[0026] Based on the first aspect, further, the solution of the outer-layer optimization problem by the bisection method to obtain the value of the relative listening rate θ specifically includes the following steps:

[0027] Step 3-1: Initialize the search interval [θ min , θ max ;

[0028] Step 3-2: Let

[0029] Step 3-3: Given θ, use the Lagrange multiplier method to solve the inner-layer optimization problem P3 to obtain the value of q k (ν)

[0030] Step 3-4: If the objective function value of Problem P3 is greater than or equal to 0, then let θ min = θ; otherwise, let θ max = θ;

[0031] Step 3-5: If θ does not converge, repeat Steps 3-1 to 3-4; otherwise, the algorithm ends.

[0032] Based on the first aspect, further, for a given relative listening rate θ, using the Lagrange multiplier method to solve the inner-layer optimization problem P3 to obtain the corresponding interference power Specifically includes: introducing a Lagrange factor λ, and repeating the following steps until λ converges;

[0033] Step 4-1: Initialize the search interval of λ as [λ min , λ max ;

[0034] Step 4-2: Let

[0035] Step 4-3: Establish the Lagrangian function and the dual function and decompose the dual function to obtain the following problems for each pair of suspicious self-organizing communication terminals k and each channel fading state ν:

[0036] P4:

[0037] Step 4-4: Based on the value of R k (v), decompose problem P4 into the following 3 sub-problems:

[0038] P5:

[0039] Constraint C3: r k (ν) - e k (ν) ≥ c k (ν);

[0040] P6:

[0041] Constraint C4: r k (ν) - e k (ν) ≤ 0;

[0042] P7:

[0043] Constraint C5: 0 ≤ r k (ν) - e k (ν) ≤ c k (v);

[0044] The solutions of the above problems P5, P6, and P7 are respectively

[0045] Step 4-4: Calculate the values of the objective function of problem P4 when q k (v) takes respectively, and let the solution of problem P4 take the value of q k (v) that maximizes the objective function;

[0046] Step 4-5: If constraint C1 does not hold when q k (v) takes , let λ min = λ; otherwise, let λ max = λ.

[0047] Based on the first aspect, further, the steps to solve problem P5 are as follows. The constraint C3 is equivalently transformed into the following form:

[0048] Constraint C6: H k,1 (ν)q k (ν) ≤ H k,2 (ν)

[0049] where

[0050] When H k,1 (v) ≥ 0, H k,2 (v) < 0, problem P5 has no solution; otherwise, the constraint C6 is further transformed into the following form:

[0051] Constraint C7: where and are respectively the minimum and maximum q k (v) values that satisfy the constraint C6;

[0052] Let the objective function of problem P5 be Z k (q k (ν)). Taking the derivative of it gives and letting Z′ k (q k (v)) = 0, the value of q k (v) can be obtained as Combined with the constraint C7, the solution of problem P5 can be obtained as:

[0053] Based on the first aspect, further, the steps to solve problem P6 are as follows:

[0054] The constraint C4 is equivalently transformed into the following form:

[0055] Constraint C8: H k,3 (ν)q k (ν) ≥ H k,4 (ν)

[0056] where

[0057] When H k,3 (v) ≤ 0, H k,4 (v) > 0, problem P6 has no solution; otherwise, the constraint C8 is further transformed into the following form:

[0058] Constraint C9: where and are the minimum and maximum q that satisfy constraint C8 k (v) values;

[0059] Let the solution of problem P6 be the minimum q that satisfies constraint C9 k (v) value, that is:

[0060] Based on the first aspect, further, the steps to solve problem P7 are as follows:

[0061] Equivalently transform constraint C5 into the following 2 constraints:

[0062] Constraint C10: H k,1 (ν)q k (ν) ≥ H k,2 (ν)

[0063] Constraint C11: H k,3 (ν)q k (ν) ≤ H k,4 (ν)

[0064] When H k,1 (v) ≤ 0, H k,2 (v) > 0 or H k,3 (ν) ≥ 0, H k,4 (ν) < 0, problem P7 has no solution; otherwise, further transform constraint C10 and constraint C11 into the following form:

[0065] Constraint C12: where and are the minimum and maximum q that satisfy constraint C10 and constraint C11 k (ν) values, written as:

[0066]

[0067]

[0068] Next, use the successive convex approximation method to solve problem P7. Let t represent the number of iterations, represent the q k (v) value of the t-th iteration. Initialize by setting t = 1, and loop through the following steps until the value converges:

[0069] (1) Rewrite the objective function of problem P7 as F k,1 (qk (ν)) - F k,2 (q k (ν)), where F k,1 (q k (ν)) = (1 - θ)c k (ν) - r k (ν) - λq k (ν), F k,2 (q k (ν)) = -e k (ν); (2) approximate F k,2 (q k (ν)) as where is the derivative of F k,2 (q k (ν)); (3) approximate the objective function F k,1 (q k (ν)) - F k,2 (q k (ν)) as and obtain its derivative as (4) use the bisection method to obtain k (q k (ν)) = 0 from the range given by the constraint C12 and the equation F′ ; (5) let t = t + 1;

[0070] Let be equal to the obtained in the above steps.

[0071] In a second aspect, the present invention further provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the legal eavesdropping method described in any one of the solutions in the first aspect is implemented.

[0072] In a third aspect, the present invention further provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the legal eavesdropping method described in any one of the solutions in the first aspect is implemented.

[0073] Compared with the prior art, the beneficial effects achieved by the present invention:

[0074] The legal eavesdropping method for physical-layer security-assisted suspicious ad-hoc communication proposed by the present invention mainly aims at the scenario where suspicious ad-hoc communication terminals use physical-layer security technology for communication. The legal eavesdropper can optimize the interference power allocation to maximize the relative eavesdropping rate of the eavesdropping node, and use active eavesdropping to interfere to reduce the channel quality of the suspicious communication link and greatly improve the eavesdropping performance. Description of the Drawings

[0075] Figure 1 It is a model diagram of the eavesdropping system in the legal eavesdropping method for suspicious ad-hoc communication in the first embodiment of the present invention;

[0076] Figure 2 It is a flowchart of the legal eavesdropping method for suspicious ad-hoc communication in the first embodiment of the present invention;

[0077] Figure 3 It is a comparison diagram of the relative eavesdropping rate and the maximum average transmit power of the eavesdropping node for each method in the comparative example of the present invention. Detailed Embodiments

[0078] The technical solution of the present invention will be described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0079] Embodiment 1

[0080] As Figure 1 and Figure 2 shown, this embodiment provides a legal eavesdropping method for physical-layer security-assisted suspicious ad-hoc communication. This method is based on an ad-hoc communication system, which includes multiple pairs of suspicious ad-hoc communication terminals and a full-duplex eavesdropping node; each pair of suspicious ad-hoc communication terminals includes a suspicious communication source and a suspicious communication destination; each suspicious communication source transmits suspicious information to the suspicious communication destination based on physical-layer security technology, and the legal eavesdropper can use the eavesdropping node to eavesdrop on the transmission of suspicious information;

[0081] The active eavesdropping method in this embodiment maximizes the relative eavesdropping rate of the interfering node by optimizing the interference power allocation of the eavesdropping node, and specifically includes the following steps:

[0082] Step 1: Establish an optimization problem model for the active eavesdropping interference power allocation of physical-layer security-assisted suspicious ad-hoc communication;

[0083] Step 2: Convert the established optimization problem into a two-layer optimization problem with inner and outer nesting. Among them, the outer-layer optimization problem optimizes the relative eavesdropping rate, and the inner-layer optimization problem optimizes the interference power allocation;

[0084] Step 3: Solve the outer optimization problem by the bisection method to obtain the relative listening rate. For a given relative listening rate, solve the inner optimization problem by the Lagrangian method to obtain the interference power allocation.

[0085] First, establish an optimization problem model P1 for the active listening interference power allocation of physical layer security assisted suspicious ad hoc communication:

[0086] P1:

[0087] Constraint C1:

[0088] This problem aims to maximize the relative listening rate of the listening node, where K is the number of suspicious ad hoc communication terminal pairs; and respectively represent the secrecy information transmission rate of the suspicious ad hoc communication terminal pair k, the codebook transmission rate of the suspicious ad hoc communication terminal pair k, the achievable rate of the listening node for the suspicious ad hoc communication terminal pair k, and the listening rate of the listening node for the suspicious ad hoc communication terminal pair k; v represents the channel fading state; ε represents the expectation over all fading states;

[0089] P k and q k (v) respectively represent the fixed transmission power of the suspicious ad hoc communication terminal pair k and the interference power of the listening node for the suspicious ad hoc communication terminal pair k; α k represents the power ratio allocated by the suspicious ad hoc communication terminal pair k for secrecy information transmission;

[0090] and respectively represent the channel gain between the transceiver of the suspicious ad hoc communication terminal pair k, the channel gain from the listening node to the destination of the suspicious ad hoc communication terminal pair k, and the channel gain from the source of the suspicious ad hoc communication terminal pair k to the listening node; ξ is the full-duplex self-interference cancellation coefficient at the listening node; σ 2 is the noise power; Q represents the maximum average transmission power of the listening node;

[0091] Constraint C1 means that the average transmission power of the listening node cannot exceed the maximum average transmission power.

[0092] In this embodiment, the established optimization problem is further transformed into a two-layer optimization problem with inner and outer nesting, including:

[0093] Step 2-1: By introducing an auxiliary variable θ to represent the relative listening rate achieved by the listening node, rewrite problem P1 as:

[0094] P2:

[0095] Constraint C2:

[0096] Constraint C1;

[0097] Step 2 - 2: Reconstruct problem P2 into a two - layer problem with inner and outer nesting. Among them, the outer - layer optimization problem optimizes θ to obtain the maximum relative listening rate value; the inner - layer optimization problem optimizes q under the condition of given θ k (v), the problem is modeled as:

[0098] P3:

[0099] Constraint C1;

[0100] Furthermore, solve the outer - layer optimization problem by the bisection method to obtain the value of θ, including:

[0101] Step 3 - 1: Given the initial search interval [θ min , θ max .

[0102] Step 3 - 2: Let

[0103] Step 3 - 3: Given θ, use the Lagrange multiplier method to solve the inner - layer optimization problem P3 to obtain q k (v) value

[0104] Step 3 - 4: If the objective - function value of problem P3 is greater than or equal to 0, then let θ min = θ; otherwise, let θ max = θ.

[0105] Step 3 - 5: If θ does not converge, repeat Steps 3 - 1 to 3 - 4; otherwise, the algorithm ends.

[0106] Furthermore, for a given θ, use the Lagrange multiplier method to solve the inner - layer optimization problem P3 to obtain the corresponding interference power including: Introduce the Lagrange factor λ, and repeat Steps 4 - 1 to 4 - 9 until λ converges;

[0107] Step 4 - 1: Given the initial search interval of λ [λ min , λ max .

[0108] Step 4 - 2: Let

[0109] Step 4 - 3: Establish the Lagrangian function and the dual function And decompose the dual function to obtain the following problems for each pair of suspicious self-organizing communication terminals k and each channel fading state ν:

[0110] P4:

[0111] Step 4-4: Based on the value of R k (ν), decompose problem P4 into the following 3 sub-problems:

[0112] P5:

[0113] Constraint C3: r k (ν) - e k (ν) ≥ c k (ν);

[0114] P6:

[0115] Constraint C4: r k (ν) - e k (ν) ≤ 0;

[0116] P7:

[0117] Constraint C5: 0 ≤ r k (ν) - e k (ν) ≤ c k (v);

[0118] Step 4-5: Solve problem P5 as follows.

[0119] Equivalently transform constraint C3 into the following form:

[0120] Constraint C6: H k,1 (ν)q k (ν) ≤ H k,2 (ν);

[0121] Where

[0122] When H k,1 (ν) ≥ 0, H k,2 (ν) < 0, problem P5 has no solution; otherwise, further transform constraint C6 into the following form:

[0123] Constraint C7: Where And are the minimum and maximum q k (ν) values that satisfy constraint C6.

[0124] Let the objective function of problem P5 be Z k (q k (ν)). Taking the derivative of it gives And let Z′ k (q k (ν)) = 0, then the value of q k (v) can be obtained as Combined with the constraint C7, the solution of problem P5 can be obtained as follows:

[0125] Step 4 - 6: The steps to solve problem P6 are as follows.

[0126] Equivalently transform the constraint C4 into the following form:

[0127] Constraint C8: H k,3 (ν)q k (ν) ≥ H k,4 (ν)

[0128] where

[0129] When H k,3 (v) ≤ 0, H k,4 (v) > 0, problem P6 has no solution; otherwise, further transform the constraint C8 into the following form:

[0130] Constraint C9: where and are respectively the minimum and maximum values of q k (v) that satisfy the constraint C8.

[0131] Let the solution of problem P6 be the minimum value of q k (v) that satisfies the constraint C9, that is:

[0132] Step 4 - 7: The steps to solve problem P7 are as follows.

[0133] Equivalently transform the constraint C5 into the following 2 constraints:

[0134] Constraint C10: H k,1 (ν)q k (ν) ≥ H k,2 (ν)

[0135] Constraint C11: H k,3 (ν)q kν ≤ H k,4 ν

[0136] When H k,1 ν ≤ 0, H k,2 ν > 0 or H k,3 ν ≥ 0, H k,4 When ν < 0, Problem P7 has no solution; otherwise, transform Constraints C10 and C11 into the following forms:

[0137] Constraint C12: where and are the minimum and maximum q values satisfying Constraints C10 and C11 respectively, written as: k ν value, written as:

[0138]

[0139]

[0140] Next, use the continuous convex approximation method to solve Problem P7. Let t represent the iteration number, represent the q k ν value at the t-th iteration. Initialize t = 1. Loop and execute the following steps until the value converges: (1) Rewrite the objective function of Problem P7 as F k,1 (q k ν) - F k,2 (q k ν), where F k,1 (q k ν) = (1 - θ)c k ν - r k ν - λq k ν, F k,2 (q k ν) = -e k ν; (2) Approximate F k,2 (q k ν) as where is the derivative of F k,2 (q k ν); (3) Approximate the objective function F k,1 (q k ν) - F k,2 (q k ν) as and obtain its derivative as (4) Use the bisection method to obtain a value from the range given by the constraint C12 and the equation F′ k (q k (ν)) = 0; (5) Let t = t + 1. The value;

[0141] Let be equal to the value obtained in the above steps.

[0142] Steps 4 - 8: Calculate the values of the objective function of problem P4 when q k (v) takes respectively, and let the solution of problem P4, take the value of q k (v) for which the objective function is the largest.

[0143] Steps 4 - 9: If the constraint C1 does not hold when q k (v) takes , let λ min = λ; otherwise, let λ max = λ.

[0144] Example Two

[0145] This example discloses a terminal device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the legal eavesdropping method disclosed in Example One.

[0146] Example Three

[0147] This example discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method disclosed in Example One.

[0148] Comparative Example

[0149] Assume that the number K of suspicious ad-hoc communication terminal pairs is 5, each suspicious ad-hoc communication terminal pair occupies a channel of 1 MHz, the noise is -100 dBm, the sinks of each suspicious ad-hoc communication terminal pair are randomly distributed on a circle with a radius of 0.5 km around its source, the sources of each suspicious ad-hoc communication terminal pair are randomly distributed on a circle with a radius ranging from 0.5 km to 1.5 km around the monitoring node, the path loss of the wireless channel is modeled as 128.1 + 37.6 log 10 d, where d is the distance in km, and the small-scale fading of the wireless channel is modeled as Rayleigh fading. In addition, let P k = 5, α k= 0.8, Q = 45 dBm, ξ = -125 dB. The following five schemes are selected as reference schemes and compared with the selection scheme in the present invention: 1) RERM. This scheme aims to maximize the relative listening rate and does not consider that the suspicious ad-hoc communication terminal pair adopts physical layer security technology, that is, it assumes that α k = 1 for the optimal design of the listening scheme; 2) AERM, this scheme aims to maximize the listening rate and does not consider that the suspicious ad-hoc communication terminal pair adopts physical layer security technology, that is, it assumes that α k = 1 for the optimal design of the listening scheme; 3) OFJPA, this scheme only interferes in those channel states where listening fails, and the interference power is evenly distributed; 4) CJPA, this scheme interferes in all channel states, and the interference power is evenly distributed; 5) PE: In this scheme, the listening node does not interfere. The variation of the relative listening rate of the six schemes with Q is as Figure 3 shown, where Q represents the maximum average transmit power of the listening node. The results show that the relative eavesdropping rate achieved by the method proposed in this application increases with the increase of Q, which is consistent with the expectation. Because when Q is larger, higher interference power can be sent from the listening node to increase the relative listening rate. The results also show that the relative eavesdropping rates achieved by the comparative schemes such as RERM, OFJPA, and CJPA may decrease with the increase of Q, while the proposed method can achieve a higher relative listening rate compared with the 5 comparative schemes.

[0150] In summary, the listening method proposed in the present invention fully bases on the characteristics of the suspicious ad-hoc communication terminal adopting physical layer security technology for communication. By optimizing the interference power distribution, it maximizes the relative listening rate of the listening node and greatly improves the listening performance compared with the traditional comparative schemes.

[0151] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0152] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be realized by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate means for realizing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for realizing the functions specified in one or more of the blocks.

[0153] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that realizes the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for realizing the functions specified in one or more of the blocks.

[0154] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for realizing the functions specified in one or more of the blocks.

[0155] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A legitimate eavesdropping method for physical-layer security-assisted suspicious ad-hoc communication, characterized in that, It includes the following steps: Establish an optimization problem model for the active listening interference power allocation of physical layer security assisted suspicious ad hoc communication; Transform the established optimization problem into a two-layer optimization problem with inner and outer nesting. Among them, the outer-layer optimization problem optimizes the relative listening rate, and the inner-layer optimization problem optimizes the interference power allocation; Solve the outer-layer optimization problem by the bisection method to obtain the relative listening rate. For the given relative listening rate, solve the inner-layer optimization problem by the Lagrangian method to obtain the interference power allocation, and optimize the relative listening rate and interference power allocation of the monitoring node; The optimization problem model for the active listening interference power allocation of physical layer security assisted suspicious ad hoc communication is: Constraint C1: The problem aims to maximize the relative listening rate of the listening nodes, where K is the number of pairs of suspicious ad-hoc communication terminals; and respectively represent the secrecy information transmission rate of the pair of suspicious ad-hoc communication terminals k, the codebook transmission rate of the pair of suspicious ad-hoc communication terminals k, the achievable rate of the pair of suspicious ad-hoc communication terminals k at the listening node, and the listening rate of the pair of suspicious ad-hoc communication terminals k at the listening node; v represents the fading state of the channel; ε represents the expectation over all fading states; P k and q k (v) respectively represent the fixed transmission power of the suspicious self-organizing communication terminal pair k and the interference power of the listening node against the suspicious self-organizing communication terminal pair k; α k represents the power ratio allocated by the suspicious self-organizing communication terminal pair k for secure information transmission; and respectively represent the channel gain between the transceiver of the suspicious ad-hoc communication terminal pair k, the channel gain from the listening node to the destination of the suspicious ad-hoc communication terminal pair k, and the channel gain from the source of the suspicious ad-hoc communication terminal pair k to the listening node; ξ is the full-duplex self-interference cancellation coefficient at the listening node; σ 2 is the noise power; Q represents the maximum average transmit power of the listening node; Constraint C1 indicates that the average transmit power of the listening node cannot exceed the maximum average transmit power; The transformation of the established optimization problem into a two-layer optimization problem with inner and outer nesting specifically includes the following steps: Step 2-1: By introducing an auxiliary variable θ to represent the relative listening rate achieved by the listening node, rewrite problem P1 as: Constraint C2: Constraint C1; Step 2-2: Reconstruct problem P2 into a two-layer problem with inner and outer nesting. Among them, the outer optimization problem optimizes θ to obtain the maximum relative listening rate value; the inner optimization problem optimizes q under the condition of a given θ k (ν), and the problem is modeled as: Constraint C1; The specific steps for obtaining the value of the relative listening rate θ by solving the outer-layer optimization problem by the bisection method are as follows: Step 3-1: Initialize the search interval [θ min , θ max ; Step 3-2: Let Step 3-3: Given θ, solve the inner-layer optimization problem P3 using the Lagrange multiplier method to obtain q k (v) value Step 3-4: If the objective function value of problem P3 is greater than or equal to 0, then let θ min = θ; Otherwise, let θ max = θ; Step 3-5: If θ does not converge, repeat steps 3-1 to 3-4; otherwise, the algorithm ends; For a given relative listening rate θ, the inner-layer optimization problem P3 is solved using the Lagrange multiplier method to obtain the corresponding interference power. Specifically, Lagrange factor λ is introduced, and the following steps are repeatedly executed until λ converges. Step 4-1: Initialize the search interval of λ as [λ min , λ max ; Step 4-2: Let Step 4-3: Establish the Lagrangian function and the dual function and decompose the dual function to obtain the following problems for each pair of suspicious self-organizing communication terminals k and each channel fading state ν: Step 4-4: Based on the value of R k (ν), decompose problem P4 into the following three sub-problems: Constraint C3: r k (ν)-e k (ν)≥c k (ν); Constraint C4: r k (ν)-e k (ν) ≤ 0; Constraint C5: 0 ≤ r k (v) - e k (v) ≤ c k (v); The solutions to the problems P5, P6, and P7 are respectively Step 4-4: Calculate the value of the objective function of problem P4 when q k (v) Take respectively and let the solution of problem P4 take the value of q with the maximum objective function k (v); Step 4-5: If the constraint C1 does not hold when q k (ν) take , let y min = λ; otherwise, let λ max = λ.

2. The legal monitoring method according to claim 1, characterized in that The steps for solving problem P5 are as follows. Equivalently transform constraint C3 into the following form: Constraint C6: H k,1 (ν)q k (ν) ≤ H k,2 (ν) Among them When H k,1 (ν) ≥ 0, H k,2 (v) < 0, Problem P5 has no solution; otherwise, the constraint C6 is further transformed into the following form: Constraint C7: wherein and are the minimum and maximum q k (v) values that satisfy constraint C6, respectively; Let the objective function of problem P5 be Z k (q k (ν)). Taking the derivative of it gives And let Z' k (q k (v)) = 0, we can obtain the value of q k (v) as Combined with the constraint C7, the solution of problem P5 can be obtained as follows:

3. The legal interception method according to claim 2, wherein The steps for solving problem P6 are as follows: Equivalently transform constraint C4 into the following form: Constraint C8: H k,3 (ν)q k (ν) ≥ H k,4 (ν) Among them When H k,3 (v) ≤ 0, H k,4 (v) > 0, problem P6 has no solution; otherwise, the constraint C8 is further transformed into the following form: Constraint C9: wherein and are the minimum and maximum q k (v) values that satisfy constraint C8, respectively; Let the solution to problem P6 be the smallest q that satisfies constraint C9 k (v) value, i.e.:

4. The legal interception method according to claim 3, characterized in that, The steps for solving problem P7 are as follows: Equivalently transform constraint C5 into the following 2 constraints: Constraint C10: H k,1 (ν)q k (ν) ≥ H k,2 (ν) Constraint C11: H k,3 (ν)q k (ν) ≤ H k,4 (ν) When H k,1 (v) ≤ 0, H k,2 (v) > 0 or H k,3 (ν) ≥ 0, H k,4 (ν) < 0, Problem P7 has no solution; otherwise, the constraints C10 and C11 are further transformed into the following forms: Constraint C12: wherein and are the minimum-maximum q k (ν) values that satisfy constraints C10 and C11, written as: Next, the continuous convex approximation method is used to solve problem P7. Let t represent the number of iterations, denote the value of q k (ν) at the t-th iteration. Initialize by setting t = 1, and loop through the following steps until the value converges: (1) Rewrite the objective function of problem P7 as F k,1 (q k (ν)) - F k,2 (q k (ν)), where F k,1 (q k (ν)) = (1 - θ)c k (ν) - r k (ν) - λq k (ν), F k,2 (q k (ν)) = -e k (ν); (2) Approximate F k,2 (q k (ν)) as where is the derivative of F k,2 (q k (ν)); (3) Approximate the objective function F k,1 (q k (ν)) - F k,2 (q k (ν)) as and obtain its derivative as (4) Use the bisection method to find k (q k (ν)) = 0 from the range given by constraint C12 and the equation F' ; (5) Let t = t + 1; Let be equal to the value obtained in the above steps.

5. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 4.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method according to any one of claims 1 to 4.

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