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Channel estimation method for underwater sound orthogonal frequency division multiplexing

A channel estimation and orthogonal frequency division technology, which is applied in the field of channel estimation to reduce Gaussian noise and interpolation error, can solve the problem of increasing transmit power, etc., and achieve the effect of improving accuracy, improving decision performance, and reducing interpolation error

Inactive Publication Date: 2012-10-10
HARBIN ENG UNIV
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Problems solved by technology

Use the superposition sequence to estimate the channel in real time, and use the judgment result to update the channel, but this method needs to increase the transmit power

Method used

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  • Channel estimation method for underwater sound orthogonal frequency division multiplexing
  • Channel estimation method for underwater sound orthogonal frequency division multiplexing
  • Channel estimation method for underwater sound orthogonal frequency division multiplexing

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Embodiment Construction

[0032] 1. Using LS algorithm to estimate the channel information at the pilot based on the comb pilot structure

[0033] Due to the complexity and change of the underwater acoustic environment, the communication channel is in a fast fading environment, and the channel characteristics within an OFDM symbol will also change significantly, and the comb pilots are evenly distributed in each OFDM symbol. Continuously distributed, with strong anti-fading ability, suitable for fast fading channels, so choose the channel estimation method based on comb structure. The inserted pilot frequency shall meet the following requirements in the time domain and frequency domain:

[0034] N f ≤ 1 τ max ΔF c - - - ( 1 )

[0035] N t ≤ 1 2 f d T - - - ( 2 )

[0036] Where N f Is the number of subcarriers of the pilot frequency interval; τ max Is the maximum delay of the channel; error! The reference source was not fo...

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Abstract

The invention belongs to the field of underwater sound communication, and particularly relates to a channel estimation method for reducing gaussian noise and interpolation error in channel estimation. The channel estimation method for underwater sound orthogonal frequency division multiplexing comprises the following steps that (1) channel frequency response estimation is obtained through the channel estimation method based on a least square method; (2) noise reduction is carried out on the pilot frequency response estimation through a wavelet noise reduction method to obtain the channel frequency response subjected to noise reduction; (3) the channel frequency response of a data sub-carrier is obtained by carrying out a discrete Fourier transform interpolation method on the channel frequency response subjected to noise reduction; and (4) the received data is balanced through the channel frequency response of the data sub-carrier, the balanced data is encoded and re-modulated, comb-shaped pilot frequency is converted into block-type pilot frequency, and the received data is judged, fed back and balanced through a block-shape minimum mean square error channel balancing method. According to the channel estimation method for underwater sound orthogonal frequency division multiplexing, the impact of the channel noise on channel estimation and the interpolation error are reduced, and the judging performance and the channel estimation precision are improved.

Description

Technical field [0001] The invention belongs to the field of underwater acoustic communication, and particularly relates to a channel estimation method for reducing Gaussian noise and reducing interpolation error in channel estimation. Background technique [0002] Orthogonal Frequency Division Multiplying (OFDM) technology is a high-rate wireless transmission technology that can effectively suppress inter-symbol interference and is widely used in underwater acoustic communications. Due to the particularity of the underwater acoustic communication environment, the transmission of information requires time-varying and frequency-selective fading channels. To achieve demodulation and recovery at the receiving end, the relevant information of the channel must be known. Therefore, channel estimation is very important for OFDM systems. [0003] In OFDM underwater acoustic communication, the inherent noise of the underwater acoustic channel has a relatively large impact on channel estimat...

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Application Information

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IPC IPC(8): H04L25/02H04L27/26H04B13/02
Inventor 郑彩云马雪飞乔钢张可周锋孙宗鑫刘凇佐章佳荣马璐廖佳玲
Owner HARBIN ENG UNIV
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