Vector sensor-based orthogonal frequency division multiplexing (OFDM) underwater sound communication method

A vector sensor and underwater acoustic communication technology, which is applied in the transmission system, baseband system components, electrical components, etc., can solve the problem of reducing the correlation between sound pressure and vibration velocity components, and achieve the effect of improving performance and good communication performance

Active Publication Date: 2011-04-20
THE 715TH RES INST OF CHINA SHIPBUILDING IND CORP
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Problems solved by technology

In the free field of the vector sensor, the sound pressure signal and the vibration velocity signal are completely correlated, but in the ocean waveguide, the correlation between the sound pressure and the vibration velocity component (especially the vertical component of the vibration velocity) is reduced

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  • Vector sensor-based orthogonal frequency division multiplexing (OFDM) underwater sound communication method
  • Vector sensor-based orthogonal frequency division multiplexing (OFDM) underwater sound communication method
  • Vector sensor-based orthogonal frequency division multiplexing (OFDM) underwater sound communication method

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Embodiment Construction

[0024] Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

[0025] The transmit signal frame structure of the underwater acoustic OFDM communication system is as follows: figure 1 As shown, the first part of each frame is a frame synchronization signal, which is used by the receiver to capture the starting position of the frame. Linear frequency modulation (LFM), hyperbolic frequency modulation (HFM) signal or spread spectrum signal can be selected as frame synchronization signal, as long as the bandwidth of the frame synchronization signal can cover the subsequent information signal; the second part is an idle delay to eliminate the multipath component of the frame synchronization signal; the third part is N filtered OFDM symbols (filter coefficient is the frame synchronization signal); the fourth part is another idle delay, which is used to eliminate the influence of multiple channels on the next frame synchronizati...

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Abstract

The invention discloses a vector sensor-based orthogonal frequency division multiplexing (OFDM) underwater sound communication method, which comprises that: a receiver uses a vertical receiving array consisting of M vector sensors of which each comprises an acoustic pressure channel and at least a vertical vibration velocity channel; after frame synchronizing signals are captured, frequency-domain passive time reversal processing is performed on the acoustic pressure channel and the vertical vibration velocity channel to combine the data of each channel into a path; and OFDM channel estimation and equalization processing are performed to finally recover original information. The vector sensor-based OFDM underwater sound communication method has the advantages that: the vector sensors form the receiver of an OFDM communication system to provide conditions for space diversity required by the time reversal processing by utilizing weak correlation between an acoustic pressure and a vertical vibration velocity component, and the vector sensor array replaces a conventional acoustic pressure array under the condition of the same receiving array size so as to remarkably improve communication performance.

Description

technical field [0001] The invention relates to underwater acoustic communication technology, mainly an OFDM underwater acoustic communication method based on a vector sensor. Background technique [0002] In recent years, with the increasing demand for underwater defense and civil ocean development, underwater acoustic communication technology has developed rapidly. The underwater acoustic channel is a space-time-frequency-variant channel with limited bandwidth and severe multi-path interference. Until now, in order to obtain robust communication performance in a complex multi-path environment, underwater acoustic communication systems usually rely on large-sized receiving arrays to resist deep fading caused by multi-path, but this method based on large-aperture array processing is difficult to meet the requirements of some installations. Applications with compact space, such as nodes for network communication. [0003] Orthogonal Frequency Division Multiplexing (OFDM) te...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B13/02H04L27/26H04L25/02
Inventor 张宏滔王忠康谢哲岳志杰
Owner THE 715TH RES INST OF CHINA SHIPBUILDING IND CORP
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