Passive intermodulation interference cancellation method and system based on recursive network

A technology of interference cancellation and passive intermodulation, used in transmission systems, electrical components, etc.

Active Publication Date: 2017-01-11
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to solve the problem of passive intermodulation interference in wireless communication and satellite communication systems, and proposes a passive intermodulation interference cancellation system and method based on a recursive network

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  • Passive intermodulation interference cancellation method and system based on recursive network
  • Passive intermodulation interference cancellation method and system based on recursive network
  • Passive intermodulation interference cancellation method and system based on recursive network

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Embodiment 1

[0087] This embodiment specifically expounds the system composition, function realization and flow diagram of applying the "recursive network-based passive intermodulation interference cancellation system and method" of the present invention to a communication system.

[0088] figure 1 It is a schematic diagram of the system composition of "a recursive network-based passive intermodulation interference cancellation system and method" in this embodiment. From figure 1 It can be seen from the figure that in this embodiment, PIM interference suppression is accomplished only through digital implementation, and the system has strong adaptability and is easy to realize by hardware.

[0089] The system receives the double-slot signal through the feature analysis and processing module, performs signal feature analysis and preprocessing, and outputs the preprocessing signal to the recursive network estimation module and the cancellation feedback adjustment module; the recursive netw...

Embodiment 2

[0124] This embodiment has specifically set forth the learning algorithm described in step 5 of the present invention and the real-time recursive learning algorithm adopted in step E in embodiment 1, and the algorithm flow is as follows image 3 shown. From image 3 It can be seen that the specific steps of the real-time recursive learning algorithm are:

[0125] Step E.1 initialization sequence time n=1;

[0126] Step E.2 initializes the recursive network parameters;

[0127] Specific to this embodiment: initialization sequence time vector, state vector, synaptic weight vector, expected response, learning rate, error precision, and state weight vector;

[0128] Among them, the initialization sequence time vector n is 1, and the state vector x(n) at time 1, that is: x(1) is initialized to 0; the synaptic weight vector w(n) is initialized to 0; the expected response d(n ) is initialized to the amplitude value of the pilot signal; the learning rate η is initialized to 0.001; t...

Embodiment 3

[0153] According to the system flow described in Embodiment 1 and the real-time recursive learning algorithm described in Embodiment 2, this embodiment specifically explains the passive intermodulation interference cancellation results of steps 1 to 9 of the present invention for 16QAM modulated signals , and compared with the existing passive intermodulation interference cancellation results based on pilot signals, the comparison results are as follows Figure 5 shown.

[0154] Figure 5 Among them, the horizontal axis represents Eb / N0, the unit is dB; the vertical axis represents the bit error rate, the unit is bit; Figure 5 The middle circular line is the bit error rate curve subject to passive intermodulation interference; the star line is the bit error rate curve suppressed by the passive intermodulation interference obtained through steps one to step nine of the cancellation method proposed by the present invention; The dashed line is the theoretical bit error rate cu...

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Abstract

The invention discloses a passive intermodulation interference cancellation method and system based on a recursive network. The system and the method comprises a passive intermodulation interference cancellation system (a cancellation system for short) based on the recursive network and a passive intermodulation interference cancellation method (a cancellation method for short) based on the recursive network. The cancellation system comprises a feature analysis processing module, a recursive network estimation module and a cancellation feedback adjustment module. The cancellation method comprises the steps of 1, receiving a signal; 2, judging whether the received signal is in a pilot time slot or not, and jumping to the 3 or 6; 3, extracting features and carrying out network initialization; 4, preprocessing the received signal and removing pilot; 5, carrying out prediction training on the recursive network, thereby obtaining a one-step-ahead prediction recursive network; 6, preprocessing a data transmission time slot receiving signal; 7, predicting a PIM interference signal of a next moment by employing a result of the 5, and finishing interference cancellation; 8, processing collected difference values before and after decoding, feeding back a processing result, and updating network parameters; and 9, judging whether cancellation is finished or not, and deciding to wait or to jump to the 6. According to the method and the device, the system adaptability is high, the cancellation precision is high, and the hardware realization is easy.

Description

technical field [0001] The invention relates to a passive intermodulation interference cancellation system and method based on a recursive network, and belongs to the technical field of signal processing and anti-interference in wireless communication, satellite communication and ground communication systems. Background technique [0002] Passive Intermodulation (PIM for short) refers to the elimination of signals generated when two or more frequency components pass through passive devices (such as duplexers, isolators, coaxial cables, connectors, antennas, loads, etc.) A phenomenon in which there are new frequency components outside the harmonics. The generated new frequency is a linear combination of the fundamental frequency, and interference is formed when the newly generated frequency falls within the passband of the communication receiver. [0003] The passive intermodulation phenomenon was discovered in the 1970s, and it exists widely in communication systems, and it...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/12
CPCH04B1/123
Inventor 徐昂梁弼政安建平卜祥元王漪方天琪
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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