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A Passive Intermodulation Interference Cancellation Method Based on Sparse Fractional Fourier Transform

A fractional Fourier and Fourier transform technology, which is applied in the field of anti-interference and can solve problems such as difficulty in parameter estimation convergence.

Active Publication Date: 2018-10-26
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to solve the problem of parameter estimation convergence difficulty in the existing passive intermodulation interference cancellation technology, further reduce the amount of calculation, improve the passive intermodulation interference cancellation effect and real-time performance, and propose a method based on sparse fraction Passive Intermodulation Interference Cancellation Method Based on Order Fourier Transform

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  • A Passive Intermodulation Interference Cancellation Method Based on Sparse Fractional Fourier Transform
  • A Passive Intermodulation Interference Cancellation Method Based on Sparse Fractional Fourier Transform
  • A Passive Intermodulation Interference Cancellation Method Based on Sparse Fractional Fourier Transform

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Embodiment 1

[0113] This embodiment describes a passive intermodulation interference cancellation system based on sparse fractional Fourier transform based on a sparse fractional Fourier transform-based passive intermodulation interference cancellation method proposed by the present invention, referred to as this system. System block diagram as figure 1 As shown, this is also a functional block diagram of implementing the method in the present invention to achieve PIM interference cancellation.

[0114] from figure 1 It can be seen that the system consists of a duplexer, a PIM parameter estimation module, a PIM interference reconstruction module, a PIM interference detection module and a PIM interference adaptive cancellation module;

[0115] The duplexer completes the transmission of the downlink signal and the reception of the uplink signal. The chirp signal is transmitted as the pilot signal of the downlink signal through the duplexer. The downlink signal includes a pilot part and a n...

Embodiment 2

[0134] This embodiment describes in detail the estimation process of the parameter information carried by the PIM interference signal generated by the pilot signal in step 2 of the present invention. Since the high-power downlink signal is completely known, the power series model is estimated by using the pilot signal. The PIM interference signal can be reconstructed to realize PIM interference cancellation. Please refer to image 3 , an embodiment of the present invention provides a method for estimating parameters of a power series model, which may include:

[0135] Step 1): normalize the dimension of the PIM interference signal produced by the pilot signal, and output the PIM interference signal produced by the dimensionally normalized pilot signal, referred to as the normalized PIM signal;

[0136] The specific steps are the same as step 2.1 in the summary of the invention. In this embodiment, the orders of the power series model are 7.3 and 8.9, and the amplitude values ...

Embodiment 3

[0174]The parameters of the power series model estimated by the PIM interference signal generated by the pilot signal and the downlink signal can be used to reconstruct the PIM interference signal. If the reconstructed PIM interference signal exceeds the set threshold, it is necessary to use a transversal filter structure for further PIM interference. Adaptive filtering, this embodiment describes in detail the process of estimating the coupling channel impulse response of the PIM interference signal transmitted from the duplexer to the receiver by using the adaptive filtering algorithm in Step 5 of the present invention on the basis of Embodiment 2.

[0175] In order to further eliminate the PIM interference signal in the received signal, an adaptive filtering algorithm is used to estimate the coupled channel impulse response h(t), and the estimation process uses digital signal processing. Using a transversal filter structure such as Figure 4 As shown, storage is represented ...

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Abstract

This invention provides a passive intermodulation interference cancellation method based on sparse fractional order Fourier transformation, and belongs to the technical field of anti-interference. The method comprises the following steps: 1, in a communication system with a transceiving antenna, transmitting a downlink signal and receiving an uplink signal by a duplexer; 2, performing sparse fractional order Fourier transformation on the received uplink signal and estimating parameter information of a power series model; 3, reestablishing a PIM (Passive Intermodulation) interference signal by using the parameter information estimated by the step 2 and the downlink signal; 4, judging whether the amplitude of the PIM interference signal reestablished in the step 3 is greater than a threshold or not, and deciding to jump to step 5 or step 6; step 5, performing PIM interference adaptive filtering by using an adaptive filtering algorithm to acquire an adaptively filtered PIM interference signal; and 6, correcting the uplink signal to complete PIM interference cancellation. Without considering the problem of convergence difficulty of parameter estimation, the method processes LFM (Linear Frequency Modulation) signals by using the sparse fractional order Fourier transformation, and realizes PIM interference suppression with low computation amount.

Description

technical field [0001] The invention relates to a passive intermodulation interference cancellation method based on sparse fractional Fourier transform, and belongs to the anti-interference technical field of wireless communication, satellite communication and ground communication systems. Background technique [0002] Passive Intermodulation (PIM for short) refers to a family of products produced by two or more frequency components through the nonlinear effect of passive devices, and its frequency is a linear combination of the fundamental frequency. Interference occurs when the linear combination products fall within the passband of a communications receiver. Passive intermodulation exists widely in communication systems and is a phenomenon that is difficult to completely eliminate. It was first discovered in the 1970s. With the improvement of communication requirements, high power and high sensitivity have become the development direction. The size of the antenna require...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/10H04B1/12
CPCH04B17/19
Inventor 卜祥元胡天存崔万照孙灿灿安建平刘建纯田露
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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