Secure transmission method with position spoofing capability for sensing fusion scene

Abstract

The invention belongs to the technical field of mobile communication, and particularly relates to a secure transmission method with position spoofing capability for a communication and sensing fusion scene. According to the method, the concept of the angle domain peak-to-average ratio is proposed by using the covariance matrix of the received signal, the estimation effect on the information source direction is measured, and the optimization problem with the angle domain peak-to-average ratio constraint is proposed with the purpose of maximizing the safety capacity. The algorithm comprises the following steps: firstly, calculating a null space of array response of the direction of an illegal party, and designing a communication signal and artificial noise in the null space; for communication signals, a generalized singular value decomposition method is adopted to carry out optimization solution; for artificial noise, a null space and projection gradient combined method is adopted to carry out optimization solution. Compared with a traditional physical layer security algorithm, the scheme provided by the invention misguides an illegal party to estimate the position of the sender while ensuring the communication security, ensures the position privacy of the sender, and has higher practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of mobile communications, and in particular relates to a secure transmission method with location deception capability for synaesthesia fusion scenarios. Background Art

[0002] The commercialization and development of the fifth generation mobile communication system has brought about new scenarios such as drone networks and vehicle networks that have both communication and perception requirements. Therefore, the Integrated Sensing And Communication (ISAC) technology has received continuous attention from the industry. The current synaesthesia fusion technology aims to enable the perception function in the communication module of the existing network, and use some of the time-frequency resources, air interface resources, hardware resources, etc. of the communication system as the processing of perception signals to achieve the perception of information such as users, passive targets, and the environment. Due to the broadcast characteristics of wireless channels and the shared use characteristics of time-frequency resources, synaesthesia fusion networks are naturally more vulnerable to the threat of privacy leakage: in terms of communication, the encryption methods of traditional cryptography have shown more decryption risks as the computing power of devices increases. Therefore, improving communication security by using the characteristics of channels at the physical layer has received widespread attention from the industry; in terms of perception, with the emergence of devices with perception functions and the continuous improvement of perception capabilities, some physical information (such as direction, distance, speed, etc.) of legitimate communication devices in the synaesthesia fusion system will be exposed. Therefore, the physical layer security algorithm that takes into account both communication security and location privacy security has become a crucial issue in the ISAC network.

[0003] However, current research on physical layer security technology generally focuses on communication security. A classic physical layer security transmission technology is to jointly design communication signals and artificial noise: on the one hand, the null space of the legitimate party channel is obtained through singular value decomposition, and the design of artificial noise in this null space will not affect the signal reception of the legitimate party; on the other hand, the precoding matrix of the communication signal is designed based on generalized singular value decomposition, which can greatly improve the confidentiality reachability. However, this design does not take into account the location privacy of the sender. In fact, even after such a design, a third party can still use array antenna technology to determine the direction of the signal, so the influence of artificial noise can be weakened by means of spatial filtering; in addition, the presence of multiple third parties can locate the location of the legitimate party, thereby specifically interfering with the legitimate party's signal transmission. Therefore, how to improve the physical layer security technology and achieve transmission that takes into account both communication security and location privacy security is a crucial issue in ensuring network security in the ISAC network. Summary of the invention

[0004] The algorithm uses the covariance matrix of the received signal to propose the concept of angle domain peak-to-average ratio, measures the estimation effect of the source direction, and proposes an optimization problem with angle domain peak-to-average ratio constraints with the goal of maximizing the security capacity. The algorithm first calculates the null space of the array response at the location of the third party, and designs the communication signal and artificial noise in this null space. For the communication signal, the generalized singular value decomposition method is used for optimization and solution; for artificial noise, the null space combined with the projected gradient method is used for optimization and solution. Compared with the traditional physical layer security algorithm, the scheme proposed in the present invention not only ensures the security of communication, but also misleads the third party's estimation of the sender's location, ensures the sender's location privacy, and has higher practicality.

[0005] In order to better illustrate the present invention, the system structure used in the technical solution of the present invention is first introduced.

[0006] Figure 1 Shown is a schematic diagram of the model involved in the present invention:

[0007] In this model, it is assumed that the number of antennas at the sender and receiver are N A 、N B , K third parties can sense the direction of the sender and receive the sent information. Assume that N A >N B >K. The number of antennas of the kth (k=1,2,…,K) third party is assumed to be M k , so the available matrix and represents the channel matrix between the sender and the receiver and the sender and the kth third party. Without loss of generality, the present invention considers the Rice channel model, that is,

[0008]

[0009] and

[0010]

[0011] where α0 and α k are the complex fading coefficients, κ0 and κ k is the Rice factor, and is the sight distance component, and Each element is independent and identically distributed in a complex Gaussian distribution Assume that the azimuth between the sender and the receiver is The azimuth of the sender, the kth third party, is For simplicity, consider the far-field model on a two-dimensional plane, where the array response vectors of the transmitter, receiver, and kth third party are and The line-of-sight component of the channel matrix can then be expressed in the form of the array response as:

[0012]

[0013] and

[0014]

[0015] In this model, the sender's sending symbol is represented by

[0016]

[0017] in For communication signals, is artificial noise, S and Z are the covariance matrices of each signal, and the scheme proposed in this invention will design these two covariance matrices. Considering that the two are independent and there is an average power constraint P A ,Right now

[0018]

[0019] When the transmission symbol is determined, the receiving signal of the receiver and the kth third party can be expressed as:

[0020] y B =Hx+n B =Hs+Hz+n B ,

[0021] and

[0022] y k =G k x+n k =G k s+G k z+n k ,

[0023] where n B With n k is an additive white Gaussian noise with a power spectral density of N0. Considering the third-party cooperative reception, the achievable rates of the legitimate party and the third party are

[0024]

[0025] and

[0026]

[0027] in

[0028]

[0029] Thus, we get the confidentiality rate C S=(C L -C I ) + At the same time, in order to mislead the third party to incorrectly estimate the sender's location, the Angular-Domain Peak-to-Average Ratio (ADPAR) is defined as follows:

[0030]

[0031] in

[0032]

[0033] represents the covariance matrix of the received signal. The definition of ADPAR shows that when The larger the angle The possibility of determining it as the direction of the received signal is also greater.

[0034] The technical solution adopted by the present invention is:

[0035] S1, for the transmitter The array response at

[0036] The conjugate transpose of is used for singular value decomposition, and we get The orthogonal basis V of the null space N ,Right now

[0037]

[0038] in is a positive definite diagonal matrix with its diagonal elements arranged in descending order;

[0039] S2, multiply the transmitted signal by V on the left N , so that the transmitted signal satisfies Achieve zero limit on third-party line-of-sight channels, that is

[0040] x=V N x′=V N (s′+z′),

[0041] in

[0042] S3, for the legal equivalent channel H′=HV N Perform singular value decomposition, that is

[0043]

[0044] in is a positive definite diagonal matrix with its diagonal elements arranged in descending order, r′ represents the rank of H′;

[0045] S4. Construct artificial noise in the null space of H′, that is,

[0046]

[0047] definition and The optimization problem is formed as follows:

[0048]

[0049] in represents the virtual direction to be constructed, γ k is a threshold greater than 1;

[0050] S5. Initialization and Calculate C S ;

[0051] S6, fix Z″ and optimize S′, specifically:

[0052] S61, take matrix pair The generalized singular value decomposition matrix Φ of H , Φ G ,Σ H ,Σ G With T,

[0053]

[0054] and

[0055] (G″Z″G″ H +N0I) -1 / 2 G′T=Φ G Σ G ,

[0056] where Φ H With Φ G is a unitary matrix, T is a non-singular matrix, Σ H With Σ G is a non-negative diagonal matrix and satisfies

[0057] S62, let S′=TS″T H , for constraints Transform, specifically: define

[0058]

[0059] and

[0060]

[0061] Thus we get

[0062] D k =T H [A′ k -g k J′ k ]T,

[0063] So we can Transformed into tr(D k S″)≥0;

[0064] S63. Simplify the optimization problem in S4 as follows:

[0065]

[0066] S64. Solving convex optimization problems

[0067]

[0068] S65. Solving convex optimization problems

[0069]

[0070] S66. Solving optimization problems using one-dimensional line search

[0071]

[0072] in

[0073]

[0074] Get the optimal solution x and the corresponding S″ at this time, so that S′=TS″T H ;

[0075] S7, fix S″ and optimize Z″, specifically:

[0076] S71, perform matrix transformation

[0077]

[0078] and

[0079]

[0080] S72. Solving optimization problems using gradient projection method

[0081]

[0082] Get the optimal solution Z″ at this time;

[0083] S73, Calculate C S And compare it with the result of the previous iteration. If the difference is less than the given threshold ε, go ​​to step S8, otherwise go to step S6;

[0084] S8. Output the optimal solution and

[0085] The beneficial effects of the present invention are:

[0086] The present invention proposes a physical layer security transmission scheme with location capability for the sender in the synaesthesia fusion scenario. The scheme first proposes the concept of angle domain peak-to-average ratio to measure the estimation effect of the third party on the direction of the source, and optimizes the communication signal and artificial noise with the goal of maximizing the security capacity under the constraint of the angle domain peak-to-average ratio. The algorithm first calculates the null space of the array response at the position of the third party, and designs the communication signal and artificial noise in this null space. For the communication signal, the generalized singular value decomposition method is used for optimization and solution; for artificial noise, the null space combined with the projected gradient method is used for optimization and solution. Compared with the traditional physical layer security algorithm, the scheme proposed in the present invention can mislead the third party's estimation of the sender's location while ensuring communication security, thereby ensuring the sender's location privacy and having higher practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 : Schematic diagram of the model involved in the present invention;

[0088] Figure 2 : A comparison diagram of the third-party beam patterns of the solution proposed in the present invention, the traditional solution, and the non-optimized solution;

[0089] Figure 3 : A comparison chart of the communication achievable rates of the scheme proposed in the present invention, the traditional scheme, and the non-optimized scheme; DETAILED DESCRIPTION

[0090] The technical solution of the present invention has been described in detail in the content of the invention. The practicability of the present invention is explained below with reference to the accompanying drawings and simulation examples.

[0091] exist Figure 2 and Figure 3 In the simulation examples, N is used unless otherwise specified. A =12, N B =8, M k =8, K = 1, η = 0.2P A , SNR = 10dB, In the system configuration, the transmitter, receiver and third party are all uniform linear arrays with antenna spacing of half a wavelength, and the Ricean factor is 1.

[0092] Figure 2A comparison chart of the third-party beam patterns of the solution proposed in the present invention (marked as Prop.), the traditional solution (marked as Conv.), and the non-optimized solution (marked as Omni.) is given. As can be seen from the figure, under the traditional physical layer security solution, the shape of the third-party beam pattern is not significantly different from that of the non-optimized solution, but it is slightly shifted downward as a whole, and there is a significant peak in the direction of the sender. This means that the third party can make a more accurate estimate of the sender's position, so the traditional solution cannot guarantee the sender's position privacy. The third-party beam pattern under the proposed scheme does not show a peak in the real direction of the sender, but instead shows a peak in the virtual direction, so it can well mislead the third party's estimate of the sender's position.

[0093] Figure 3 The communication achievable rates of the scheme proposed by the present invention, the traditional scheme, and the non-optimized scheme are given. As can be seen from the figure, the confidentiality rate of the proposed scheme is slightly lower than that of the traditional physical layer security scheme, but significantly higher than that of the non-optimized scheme. This means that the proposed scheme does not cause much loss in the security performance of communication.

[0094] It can be seen that the physical layer security solution proposed by the present invention for the sender of the synaesthesia fusion scenario with the ability to spoof location has shown significant advantages over traditional physical layer security solutions: the solution proposed by the present invention can simultaneously achieve the disguise of the sender's location and the improvement of the communication confidentiality rate, and has higher practicality.

Claims

1. A secure transmission method with location deception capability for synaesthesia fusion scenarios, wherein the system includes a A A transmitter with N antennas, B The receiver has a root antenna, and K third parties that can sense the direction of the sender and receive the sent information. The number of antennas of the kth third party is M k , k = 1, 2, ..., K; use the matrix and represents the channel matrix between sender and receiver and sender and the kth third party, satisfying the Rice channel model, that is, and where α0 and α k are the complex fading coefficients, κ0 and κ k is the Rice factor, and is the sight distance component, and Each element is independent and identically distributed in a complex Gaussian distribution The non-line-of-sight component of; the azimuth between the sender and the receiver is The azimuth of the sender, the kth third party, is Considering the far-field model on a two-dimensional plane, the array response vectors of the transmitter, receiver, and kth third party are and The line-of-sight component of the channel matrix is ​​expressed in the form of array response as: and The sender's sending symbol is represented as x=s+z, in For communication signals, is artificial noise, S and Z are the covariance matrices of each signal, and the two are considered to be independent and have an average power constraint P A ,Right now The received signal of the receiver and the kth third party is expressed as: y B =Hx+n B =Hs+Hz+n B , and y k =G k x+n k =G k s+G k z+n k , where n B With n k is an additive white Gaussian noise with a power spectral density of N0; the achievable rates of the legitimate party and the third party are: C L =logdet[I+HSH H (HZH H +N0I) -1 ], and C I =log[I+GSG H (GZG H +N0I) -1 ], in Thus, we get the confidentiality rate C S =(C L -C I ) + ; In order to mislead the third party to incorrectly estimate the sender's position, the angle domain peak ratio is defined as follows: in represents the covariance matrix of the received signal; when The larger the angle The possibility of judging it as the direction of receiving signal is also greater; It is characterized in that The secure transmission method comprises: Under the constraint of the angle domain peak-to-average ratio, the two covariance matrices S and Z are optimized to achieve secure transmission, including: S1, for the transmitter The array response at The conjugate transpose of is used for singular value decomposition, and we get The orthogonal basis V of the null space N ,Right now in is a positive definite diagonal matrix with its diagonal elements arranged in descending order; S2, multiply the transmitted signal by V on the left N , so that the transmitted signal satisfies Achieve zero limit on third-party line-of-sight channels, that is x=V N x′=V N (s′+z′), in S3, for equivalent channel H′=HV N Perform singular value decomposition, that is in is a positive definite diagonal matrix with its diagonal elements arranged in descending order, r′ represents the rank of H′; S4. Construct artificial noise in the null space of H′, that is, definition and The optimization problem is formed as follows: s.t.trS″+trZ″=P A , in represents the virtual direction to be constructed, γ k is a threshold greater than 1; S5. Initialization and Calculate C S ; S6, fix Z″ and optimize S′, specifically: S61, take matrix pair The generalized singular value decomposition matrix Φ of H , Φ G ,Σ H ,Σ G With T, and (G″Z″G″ H +N0I) -1 / 2 G′T=Φ G Σ G , where Φ H With Φ G is a unitary matrix, T is a non-singular matrix, Σ H With Σ G is a non-negative diagonal matrix and satisfies S62, let S′=TS″T H , for constraints Transform, specifically: define and Thus we get D k =T H [A′ k -g k J′ k ]T, Will Transformed into tr(D k S″)≥0; S63. Simplify the optimization problem in S4 as follows: s.t.trS″=P A -trZ″, tr(D k S″)≥0, S64. Solving convex optimization problems sttr(T H TS″)=P A -trZ″, tr(D k S″)≥0, S65. Solving convex optimization problems S66. Solving optimization problems using one-dimensional line search in Get the optimal solution x and the corresponding S″ at this time, so that S′=TS″T H ; S7, fix S″ and optimize Z″, specifically: S71, perform matrix transformation and S72. Solving optimization problems using gradient projection method Get the optimal solution Z″ at this time; S73, Calculate C S And compare it with the result of the previous iteration. If the difference is less than the given threshold ε, go ​​to step S8, otherwise go to step S6; S8. Output the optimal solution and

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