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Anti-Multipath Underwater Acoustic Communication Method Based on Orthogonal Carrier Sweep Spread Technology

A technology of orthogonal carrier and underwater acoustic communication, applied in multi-carrier systems, electrical components, transmission systems, etc., can solve problems such as low frequency spectrum utilization, improve communication speed, improve communication performance and communication speed, and increase communication speed Effect

Active Publication Date: 2018-08-17
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a kind of anti-multi-channel communication system based on orthogonal carrier sweep and spread technology that solves the problem that the spectrum utilization rate is low when the traditional sweep-spread modulation communication method has better system anti-Doppler capability. acoustic communication method

Method used

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  • Anti-Multipath Underwater Acoustic Communication Method Based on Orthogonal Carrier Sweep Spread Technology
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  • Anti-Multipath Underwater Acoustic Communication Method Based on Orthogonal Carrier Sweep Spread Technology

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specific Embodiment approach 1

[0035] Specific implementation manner 1: An anti-multipath underwater acoustic communication method based on orthogonal carrier sweeping and spreading technology includes the following steps:

[0036] Step 1. The transmitting end uses the orthogonal chirp signal as the carrier, that is, the orthogonal carrier, and adopts the phase modulation method to encode, interleave and symbol map the binary information stream and then modulate it on this orthogonal carrier for transmission; the orthogonal carrier The mathematical expression of the signal is c 1 (t) and c 2 (t);

[0037] Step 2, such as Figure 5 As shown, the transmitted signal in step 1 reaches the communication receiving end after passing through the channel, and the received signal r(k) is sent to two parallel signal processing branches. The steps of the two signal processing branches are as follows:

[0038] Step 2.1. The first signal processing branch performs frame synchronization, despreading, matched filtering on the rece...

specific Embodiment approach 2

[0056] Specific implementation manner 2: c in step 1 of this implementation manner 1 (t) and c 2 (t) is expressed as follows:

[0057]

[0058] Among them, A c Is the amplitude; t is time; m is frequency modulation slope; f l Is the lowest frequency of the orthogonal carrier; f h Is the highest frequency of the orthogonal carrier; T sw Is the pulse width of the orthogonal carrier.

[0059] The other steps are the same as in the first embodiment.

specific Embodiment approach 3

[0060] Specific implementation mode 3: According to figure 1 with figure 2 To describe this embodiment, the specific operation steps of step 1 of this embodiment are as follows:

[0061] Step 1.1: Channel coding the binary information stream to obtain an encoded binary bit stream;

[0062] Step 1.2: Perform an interleaving operation on the coded binary bit stream to obtain an interleaved coded binary bit stream;

[0063] Step 1.3: Insert a binary training bit stream into the coded binary bit stream after interleaving;

[0064] Step 1.4: Perform phase modulation on the binary bit stream obtained in step 1.3 to obtain a baseband symbol sequence;

[0065] Step 1.5: Divide the baseband symbol sequence into two according to the sequence length, and obtain two pulse-shaped symbol sequences after pulse shaping and filtering respectively;

[0066] Step 1.6: Modulate one of the symbol sequences of the two pulse-shaped symbol sequences to the orthogonal carrier c 1 (t), the other way is modulate...

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Abstract

The invention relates to the field of underwater acoustic communication technology, and especially relates to an underwater acoustic communication method under channel multipath conditions. The underwater acoustic communication method provided by the invention comprises the steps that: a transmitting terminal adopts orthogonal linear frequency modulated signals as carriers; a transmission signal arrives at a communication receiving terminal after passing by a channel; and two paths of output sequences are merged in the following manner to obtain an estimated value of a transmission symbol, and underwater acoustic communication is carried out according to the estimated value. According to the underwater acoustic communication method provided by the invention, sweep expansion modulation of information is carried out by use of orthogonal carriers to improve the communication rate of a communication system, and the receiving terminal compensates residual Doppler and inhibits multipath expansion by use of a bidirectional decision feedback equalizer which is embedded in a second order phase-locked loop. Compared with a traditional sweep expansion modulation communication method, the underwater acoustic communication method provided by the invention can be used for effectively reducing the interference of multipath and Doppler and improving the communication performance and the communication rate, and the communication rate is increased by more than 20%. Meanwhile, the underwater acoustic communication method provided by the invention can be used for obtaining better channel multipath separation ability by a smaller system working bandwidth.

Description

Technical field [0001] The invention relates to the technical field of underwater acoustic communication, in particular to an anti-multipath underwater acoustic communication method based on orthogonal carrier sweeping and spreading technology under the condition of multiple channels. Background technique [0002] Spread spectrum communication uses a specific spread spectrum function to expand the spectrum of the signal to be transmitted to a wide available bandwidth at the transmitter end. The receiver uses the same spread spectrum function as the transmitter end as a local despread reference signal. Operation despreading is restored to the original communication mode of narrowband signals, which has the advantages of anti-interference, anti-fading, and good concealment. Spread spectrum communication can be achieved in the following ways: (1) Direct sequence spread spectrum technology uses high-rate pseudo-random codes at the transmitter to spread spectrum modulation of the low-...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/32H04B1/69
CPCH04B1/69H04B2001/6912H04L27/32
Inventor 张友文孙大军杨琪王彤刘松尹子予勇俊刘鑫
Owner HARBIN ENG UNIV