Secure transmission method with position hiding 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 hiding capability for a communication and sensing fusion scene. The method comprises the following steps of: firstly, calculating a null space of array response of an azimuth where an illegal party is located, taking an orthogonal basis of the null space as a position hiding precoding matrix, then multiplying a channel of a legal party by the matrix to obtain an equivalent channel, performing singular value decomposition on the equivalent channel to obtain a null space of the equivalent channel, and transmitting artificial noise in the null space of the equivalent channel to obtain a position hiding precoding matrix. Communication signals are transmitted in an orthogonal complement space of the null space of the equivalent channel. As the array response of the direction where the illegal party is located corresponds to the sight distance channel, the provided scheme can null the signal in the sight distance channel of the illegal party, so that the illegal party cannot correctly deduce the position of the sender. Compared with a traditional physical layer security algorithm, the scheme provided by the invention realizes hiding of the position of the sender while ensuring communication security, and has higher use value.

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 position hiding capability for synaesthesia fusion scenarios. Background Art

[0002] The commercial use of the fifth generation mobile communication system and the cutting-edge research of the sixth generation communication system have brought about new scenarios with both communication and perception requirements, such as smart factories, drone networks, and vehicle networks. Therefore, the Integrated Sensing And Communication (ISAC) technology has received continuous attention and in-depth research from the industry. The Integrated Sensing And Communication technology enables the perception function in the communication module and uses the spectrum resources, air interface technology, and hardware resource processing unit of the communication system to receive and process the perception signals, thereby achieving multi-dimensional perception of the environment and targets. From the opposite perspective, due to the broadcast characteristics of the wireless channel and the shared use of the spectrum, the ISAC network is also more vulnerable to the threat of privacy leakage: in terms of communication, the traditional cryptographic security transmission method has revealed more decryption risks with the improvement of computing power; on the other hand, the location information of some private devices has also been exposed to illegal devices with perception capabilities. In order to take into account the privacy of both communication information and location information, the design of new physical layer security solutions has become an issue that cannot be ignored in the ISAC network.

[0003] In the face of security challenges in ISAC networks, current research generally focuses on using perception capabilities to obtain channel state information, and based on this, designs targeted physical layer security transmission technologies to achieve improved communication security performance. A typical physical layer security transmission system is to jointly design precoding technology and artificial noise technology, obtain the null space of the legitimate receiver channel through singular value decomposition, design artificial noise in the null space, and transmit communication signals in the orthogonal complementary space of the null space, which can effectively reduce the signal-to-noise ratio of the third party without affecting the normal transmission of the receiver. However, the above scheme does not take into account the location privacy security of the sender, because the third party can always use the received signal of the antenna array to infer the direction of the incoming wave and ultimately infer the sender's location. Summary of the invention

[0004] This scheme first calculates the null space of the array response at the location of the third party, uses its orthogonal basis as the position hiding precoding matrix, then multiplies the channel of the legal party by the matrix to obtain an equivalent channel, and then performs singular value decomposition on it to obtain the null space of the equivalent channel, transmits artificial noise in the null space of the equivalent channel, and transmits communication signals in the orthogonal complementary space of the null space of the equivalent channel. Since the array response at the location of the third party corresponds to the line-of-sight channel, the proposed scheme can null the signal in the line-of-sight channel of the third party, making it impossible for the third party to correctly infer the position of the sender. Compared with the traditional physical layer security algorithm, the scheme proposed in the present invention achieves the hiding of the sender's position while ensuring communication security, and has higher use value.

[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] x=s+z,

[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] C L =logdet[I+HSH H (HZH H +N0I) -1 ],

[0025] and

[0026] C I =logdet[I+GSG H (GZG H +N0I)-1 ],

[0027] in

[0028]

[0029] Thus, we get the confidentiality rate C S =(C L -C I ) + .

[0030] The technical solution adopted by the present invention is:

[0031] S1, for the transmitter The array response at

[0032] The conjugate transpose of is used for singular value decomposition, and we get The orthogonal basis V of the null space N ,Right now

[0033]

[0034] in is a positive definite diagonal matrix with its diagonal elements arranged in descending order;

[0035] 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

[0036] x=V N x′=V N (s′+z′),

[0037] in

[0038] S3, for equivalent channel H′=HV N Perform singular value decomposition, that is

[0039]

[0040] in is a positive definite diagonal matrix with its diagonal elements arranged in descending order, r′ represents the rank of H′;

[0041] S4. Construction

[0042]

[0043] and

[0044]

[0045] The optimization problem is formed as follows:

[0046]

[0047] S5. Since the addition of artificial noise will reduce the signal-to-noise ratio at the receiver, if the minimum transmission power η of artificial noise is given, then the optimal solution of Z″ is Must satisfy So we can get an optimal solution as follows:

[0048]

[0049] S6. Bring the result of S5 into S4 for simplification, and obtain

[0050]

[0051] The optimal solution to the above optimization problem is obtained using the CVX program

[0052] S7. Output the optimal solution and

[0053] The beneficial effects of the present invention are:

[0054] The present invention proposes a physical layer secure transmission scheme for the sender with the ability to hide the position of the sender in the synaesthesia fusion scenario. The scheme first finds the null space of the array response of the third-party orientation, and performs subsequent design in the null space, so that the third party cannot obtain useful information from the line-of-sight channel, thereby achieving the effect of hiding the sender's position. Subsequently, artificial noise is added to the null space of the equivalent channel of the legal party, and the communication signal is transmitted in the orthogonal complementary space of the equivalent channel null space to enhance the security of the communication data. By incorporating the sender's location privacy into the optimization problem, the present invention provides an effective solution for scenarios in ISAC networks that have both location confidentiality requirements and secure communication requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 : Schematic diagram of the model involved in the present invention;

[0056] 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;

[0057] 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

[0058] 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.

[0059] 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.

[0060] Figure 2 A comparison chart of the third-party beam patterns of the proposed solution (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 third-party beam pattern is not significantly different from the non-optimized solution, and both show a significant peak in the direction of the sender. This means that the third party can make a relatively accurate estimate of the sender's location, so the traditional solution cannot guarantee the sender's location privacy. The third-party beam pattern under the proposed solution is very flat, so it can hide the sender's location well.

[0061] 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.

[0062] It can be seen that the physical layer security solution with the ability to hide the location of the sender in the synaesthesia fusion scenario proposed by the present invention shows significant advantages over the traditional physical layer security solution: the solution proposed by the present invention can simultaneously achieve the hiding 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 hiding capability for synaesthesia fusion scenarios, defining a system including 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 It is characterized in that The secure transmission method comprises: Two covariance matrices 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. Construction and The optimization problem is formed as follows: s.t.trS″+trZ″=P A , S″ H =S″,S″s O, WITH" H =Z″,Z″s O, S5. Given the minimum artificial noise transmission power η, the optimal solution of Z″ is Must satisfy The optimal solution is as follows: S6. Bring the result of S5 into S4 for simplification, and obtain s.t.trS″=P A -η, S″ H =S″,S″s O, The optimal solution to the above optimization problem is obtained using the CVX program S7. Output the optimal solution and

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