Frequency hopping pulse bit encoding underwater acoustic communication method based on linear frequency modulation signals

A chirp signal, pulse position coding technology, applied in the direction of climate sustainability, sustainable communication technology, ultrasonic/sonic/infrasonic transmission system, etc., can solve the problem of long time extension, long communication distance, multipath signal energy attenuation big problem

Inactive Publication Date: 2014-01-08
SOUTH CHINA UNIV OF TECH
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  • Abstract
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Problems solved by technology

Second, although the time delay of some multipath interference signals is longer than the time length of one frame, due to the relatively long time extension a

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  • Frequency hopping pulse bit encoding underwater acoustic communication method based on linear frequency modulation signals
  • Frequency hopping pulse bit encoding underwater acoustic communication method based on linear frequency modulation signals
  • Frequency hopping pulse bit encoding underwater acoustic communication method based on linear frequency modulation signals

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Embodiment Construction

[0062] The specific implementation process of the present invention and its own characteristics and advantages will be described in detail below in conjunction with examples and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0063] An underwater acoustic communication method based on chirp signal-based frequency-hopping pulse position coding, which specifically includes the following contents.

[0064] 1. Signal transmitter modulation method:

[0065] Step 1: Information source integration.

[0066] In the initial stage of source coding, the symbol stream after binary code stream integration will be obtained, and the symbols include the above-mentioned zero symbols and non-zero combined symbols. Steps in the source code integration phase, such as Image 6 , 7 Shown:

[0067] ① Input the binary code stream and search sequentially. If it is a 0 bit, it will be directly stored in the memory, and 0 will be regarded as a single b...

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Abstract

The invention discloses a frequency hopping pulse bit encoding underwater acoustic communication method based on linear frequency modulation signals. The method comprises the steps of utilizing the characteristic that time slots are not overlapped in underwater multipath interference, adopting modulation combination of frequency modulation encoding and pulse bit encoding to conduct modulation on information, increasing the number of the time slots of each frame by increasing the quantity of frequency hopping to improve the time length of each frame, enabling the delay spread of most multipath signals to be smaller than the duration time of each frame, and utilizing a filter for extracting main path signals from a frequency domain at a receiving terminal. According to the frequency hopping pulse bit encoding underwater acoustic communication method based on the linear frequency modulation signals, on the premise that the multipath interference resistance performance is ensured, devices of a transmitting terminal and the receiving terminal are simplified, the power required by transmission is reduced, the speed of data transmission is increased, and the defects that a traditional underwater acoustic communication technology is complex in device, large in power consumption, large in multipath interference on information, slow in transmitting speed and the like are overcome.

Description

technical field [0001] The invention relates to the underwater communication field and pulse position encoding technology, in particular to a frequency-hopping pulse position encoding underwater acoustic communication method based on a linear frequency modulation signal (LFM). Background technique [0002] Since seawater is a poor conductor of radio, the penetration of radio in it is difficult to meet the design requirements of data communication in most communication systems. Underwater acoustic communication is considered to be the most promising underwater communication method because of its strong underwater penetration, convenience, flexibility, economy, and no cables. The biggest difficulty in underwater acoustic communication is the multipath effect: the sound propagation speed in seawater is about 1500m / s, and the reflection and scattering caused by sound propagation cannot be eliminated. So the sound waves will take different paths to reach the receiving end. In a...

Claims

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Application Information

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IPC IPC(8): H04B13/02H04B1/713H04B1/10H04B11/00
CPCY02D30/70
Inventor 宁更新张华昱季飞
Owner SOUTH CHINA UNIV OF TECH
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