Differential cyclic shift spread-spectrum underwater sound communication method

A differential loop, underwater acoustic communication technology, applied in multiplex communication, error prevention, multi-frequency code system, etc., can solve the problems of large receiver calculation, inconvenient real-time processing, and high complexity, and achieve easy real-time implementation. , the effect of strong confidentiality and low computational cost

Inactive Publication Date: 2009-10-28
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

[0018] Therefore, the existing direct sequence spread spectrum underwater acoustic communication data rate is too low, while the M-element spread s...

Method used

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  • Differential cyclic shift spread-spectrum underwater sound communication method
  • Differential cyclic shift spread-spectrum underwater sound communication method
  • Differential cyclic shift spread-spectrum underwater sound communication method

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Embodiment Construction

[0033] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific implementation examples.

[0034] (1). The basic spreading code is composed of 1-2 spreading codes, and the spreading code can be pseudo-random code or chaotic code.

[0035] The basic spreading codes required in the present invention can be m-sequences, Gold sequences, Kasami sequences and chaotic sequences, all of which have good cyclic correlation characteristics. Let the spreading sequence be x=(x 1 , x 2 ,...x N ), N is the sequence length, then the autocorrelation function of the spreading sequence is:

[0036] R ( j ) = 1 , j = 0 1 N ...

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Abstract

The invention discloses a differential cyclic shift spread-spectrum underwater sound communication method, which comprises the following steps: forming a basic spread-spectrum code by 1 to 2 spread-spectrum codes, and adopting a phase or a frequency to modulate a carrier wave to form a corresponding basic spread-spectrum waveform; at a communication sending end, determining the size of cyclic shift according to information to be sent, carrying out differential cyclic shift for the basic spread-spectrum waveform so as to realize multi-modulation, and sending the cyclic shift waveform into an underwater sound channel through a transmitting transducer; adopting a channel matching and filtering method to carry out multi-path combination at a receiving end; and using FFT to carry out quick cyclic correlation for received signals, judging the size of the cyclic shift according to a peak value of a related output waveform, and further carrying out decoding. The method effectively improves the communication rate, has low calculation amount and simple receivers, is convenient to realize in real time, can flexibly adjust the communication rate, can realize the multi-path combination, and has the advantages of good concealment performance, low captured probability and strong confidentiality.

Description

technical field [0001] The present invention relates to the field of underwater acoustic communication, more specifically, relates to a low-complexity, low-power-consumption spread spectrum communication method in medium and long-distance underwater acoustic communication. Background technique [0002] With the rapid development of human beings in the development of marine resources, countries all over the world have more and more urgent requirements for underwater information transmission technology. Underwater acoustic communication is the main form of long-distance transmission of underwater information, and it is one of the high-tech urgently needed by countries covering marine technology and information technology. [0003] Underwater acoustic channels can generally be characterized as time-, frequency-, and space-variant channels with limited bandwidth and severe multipath interference. The complexity and variability of underwater acoustic channels severely limit the ...

Claims

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Application Information

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IPC IPC(8): H04B13/02H04B1/707H04L27/00H04L27/26H04J13/00H04L1/00
Inventor 何成兵黄建国韩晶张群飞雷开卓申晓红
Owner NORTHWESTERN POLYTECHNICAL UNIV
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