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A directional modulation method and system based on extended weighted fractional Fourier transform

A technology of fractional Fourier transform and directional modulation, applied in secure communication, electrical components, etc., can solve problems such as interception by eavesdroppers, large communication area, etc., achieve safe transmission, realize safety performance, and reduce the probability of intercepting signals Effect

Active Publication Date: 2022-08-05
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of being easily intercepted by eavesdroppers due to the large communicable area in space in the existing directional modulation security scheme, and propose a directional modulation method based on extended weighted fractional Fourier transform and system

Method used

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  • A directional modulation method and system based on extended weighted fractional Fourier transform
  • A directional modulation method and system based on extended weighted fractional Fourier transform
  • A directional modulation method and system based on extended weighted fractional Fourier transform

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specific Embodiment approach 1

[0032] Specific implementation mode 1. Combination figure 1 and figure 2 This embodiment will be described. The directional modulation method based on the extended weighted fractional Fourier transform described in this embodiment specifically includes the following steps:

[0033] Step 1: Perform baseband constellation mapping on the 0 and 1 bit data generated by the source to obtain the modulated signal X after the constellation mapping;

[0034] Step 2: Perform multi-component generation on the modulated signal X obtained in step 1 by expanding the weighted fractional Fourier transform to obtain four serial digital signals F. l 0 , F l 0 Represents the obtained serial digital signal of No. 1, l=0, 1, 2, 3;

[0035]

[0036] In the formula, X l is the result of performing l-time Fourier transform on the signal X, i is an imaginary unit, Transform parameters generated for the extended weighted fractional Fourier transform multi-component, k = 0, 1, 2, 3,

[00...

specific Embodiment approach 2

[0057] Embodiment 2: The difference between this embodiment and Embodiment 1 is that in step 6, the four channels of analog modulation signals obtained in step 5 are respectively Perform up-conversion processing to obtain four-channel signals after up-conversion processing; the specific process is as follows:

[0058]

[0059] In the formula, Represents the first signal after up-conversion processing, f c is the carrier modulation center frequency, t is the timing mark, Re[ ] represents the real part, and e represents the base of the natural logarithm.

specific Embodiment approach 3

[0060] Embodiment 3: The difference between this embodiment and Embodiment 2 is that in step 7, the receiving end receives the signal through a single antenna, and the form of the signal received by the receiving end is:

[0061]

[0062] In the formula, Y R1 is the signal received by the receiver, H l is the channel state information matrix of the channel 1 signal after up-conversion processing, N T is random noise.

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Abstract

A directional modulation method and system based on extended weighted fractional Fourier transform belong to the technical field of wireless communication. The present invention solves the problem of easy interception by eavesdroppers due to the large communicable area in space in the existing directional modulation security scheme. The invention can realize the anti-interception signal form and the controllable communicable area design with both distance correlation and offset angle correlation characteristics by utilizing the self-interference characteristics of the extended weighted fractional Fourier transform multi-component and the frequency-controlled array. The method of the invention greatly reduces the low bit error rate area in the space. In a network where eavesdroppers exist, even if the relevant knowledge of fractional domain transformation is public and all transformation parameters can be brute force cracked at the cost of higher computational complexity , it cannot achieve high probability interception of the signal. The physical layer security performance of the hybrid carrier system is enhanced, and the confidentiality of communication is guaranteed. The present invention can be applied to the technical field of wireless communication.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a directional modulation method and system based on extended weighted fractional Fourier transform. Background technique [0002] With the vigorous development of information and communication technology, people have a higher demand for the security performance of communication, and the theory and technology of information security have attracted extensive attention. With the development of technology and in-depth research, physical layer security technology, as an effective supplement to the upper layer encryption system, has been studied more and more because of its unique advantages in enhancing system security performance. In recent years, the weighted fractional Fourier transform has been gradually studied and applied in communication systems, and has also been applied in various research fields of physical layer security, and has achieved certain ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04K1/00
CPCH04K1/003
Inventor 沙学军宋鸽房宵杰殷雪琦
Owner HARBIN INST OF TECH