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A multicarrier modulation method based on underwater acoustic sparse orthogonal frequency division multiplexing

A multi-carrier modulation, orthogonal frequency division technology, applied in modulated carrier systems, ultrasonic/acoustic/infrasonic transmission systems, multi-frequency code systems, etc. The effect of improving performance, reducing bit error rate, and improving quality

Inactive Publication Date: 2019-01-22
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, OFDM subcarriers have very strict requirements on their orthogonality and must be absolutely orthogonal, otherwise errors will occur during demodulation at the receiving end, resulting in an increase in the bit error rate

Method used

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  • A multicarrier modulation method based on underwater acoustic sparse orthogonal frequency division multiplexing
  • A multicarrier modulation method based on underwater acoustic sparse orthogonal frequency division multiplexing
  • A multicarrier modulation method based on underwater acoustic sparse orthogonal frequency division multiplexing

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Embodiment 1

[0034] The embodiment of the present invention designs a multi-carrier frequency division multiplexing modulation method suitable for underwater acoustic communication based on OFDM and compressed sensing, which is called SOFDM. The embodiment of the present invention is based on OFDM, replaces the FFT / IFFT part in traditional OFDM multi-carrier modulation with the dictionary matrix that adopts in compressed sensing, reduces the bit error rate of system, and this method comprises the following steps:

[0035] Such as figure 1 As shown, the binary bit stream information generated by the signal source is encoded by the source to obtain the encoded information encoded information After channel coding, the data is obtained data Mapped to QPSK signal after QPSK (Quadrature Phase Shift Keying) modulation Signal After passing through the SOFDM modulator, the transmission data is generated send data Included in the QPSK signal all the information for . After adding t...

Embodiment 2

[0038] The scheme in embodiment 1 is further introduced below in conjunction with specific calculation formulas and examples, see the following description for details:

[0039] 1. Transmitter

[0040] The modulation process of the SOFDM modulator at the transmitting end is as follows:

[0041] in, For QPSK signal, is the modulated SOFDM signal. G is a dictionary matrix, and its generation method is as follows: G=(g 0,0 , g 0,M-1 ,..., g k,m ,..., g N-1,0 ,...g N-1,M -1)(2)

[0042] Among them, g k,m Indicates the mth aliasing of the kth subcarrier, the expression is as follows:

[0043] g k,m [n]=δ[(n-mΔ)modN]*g k [n] (3)

[0044] n=0,1,2,...,N-1,

[0045] k=0,1,2,...,N-1,

[0046] m=0,1,2,...,M-1,

[0047] Among them, n, k, and m represent time domain index, frequency domain index and delay index respectively, Δ represents the time length of delay, mod is a remainder operation, and N is the number of orthogonal subcarriers in OFDM. M is the number of sub...

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Abstract

The invention discloses a multi-carrier modulation method based on underwater acoustic sparse orthogonal frequency division multiplexing, including: a transmitter end : the binary bit stream information generated by the signal source is encoded by the source to obtain encoded information (img file= 'DDA00018430800000011. TIF' wi= '67' he= '63' / ) (img file= 'DDA00 018430800000012. TIF 'wi=' 36 'he=' 60 ' / ) Channel coded data (img file=' DDA00018430800000013. TIF 'wi=' 73 'he=' 78 ' / ) data (img file=' DDA00018430800000014. TIF 'wi=' 51 'he=' 78 ' / ) are mapped to a signal (img file=' DDA00018430800 00000015. TIF 'wi=' 67 'he=' 66 ' / ) signal (img file=' DDA000184308000016. TIF 'wi=' 40 'he=' 61 ' / ) is modulated by a demodulator. Generate send data (img file= 'DDA00018430800000017. TIF' wi= '61' he= '62' / ) Send data (img file= 'DDA00018430800000018. TIF 'wi=' 40 'he=' 65 ' / ) contains all the information about the signal (img file =' DDA00018430800000019. TIF 'wi=' 40 'he=' 57 ' / ). Transmitdata (img file= 'DDA0001843080000110. TIF' wi= '35' he= '64' / ) with cyclic suffix and frame header signal, become a complete frame signal and send it to the actual underwater acoustic channel throughhydrophone. The receiving end obtains a received signal with a cyclic prefix, Remove cyclic prefix, after obtaining the modulated data (img file = 'DDA000184308000000111. TIF' wi= '64' he= '69' / ) at the receiving end and demodulating by the demodulator. The received quadrature phase shift keying signal (img file= 'DDA0001843080000001112. TIF' wi= '65' he= '81' / ) is demapped to a bit stream (img file= 'DDA00018430 8000000113. TIF 'wi=' 75 'he=' 99 ' / ) bit stream (img file=' DDA0001843080000114. TIF 'wi=' 44 'he=' 83 ' / ) is channel decoded to (i mg file= 'DDA000184308000000115. TIF' wi= '123' he= '72' / ) Obtains binary bitstream information after source decoding.

Description

technical field [0001] The present invention relates to the technical field of digital multi-carrier transmission, in particular to applying the idea of ​​compressed sensing to multi-carrier modulation on the basis of Orthogonal Frequency Division Multiplexing (OFDM), and proposes an underwater acoustic sparse Orthogonal Frequency Division Multiplexing The multi-carrier (SOFDM) modulation method used. Background technique [0002] At present, the application of underwater acoustic communication is more and more extensive. However, the underwater acoustic channel is known as one of the most challenging channels due to its characteristics of large noise, large propagation delay and serious multipath effects. [0003] Orthogonal Frequency Division Multiplexing (OFDM) can deal with the multipath effect in the channel by adding a cyclic prefix, which eliminates inter-symbol interference and inter-subcarrier interference to a certain extent, and has good robustness. Therefore, O...

Claims

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Application Information

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IPC IPC(8): H04L27/26H04B11/00H04B13/02
CPCH04B11/00H04B13/02H04L27/2601H04L27/2627H04L27/2649
Inventor 叶东来刘敬浩付晓梅
Owner TIANJIN UNIV
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