Doppler extension processing method for underwater acoustic high speed ofdm communication

Abstract

The invention discloses a Doppler extension processing method for underwater acoustic high-speed OFDM communication. The method is composed of the following three modules, including a Doppler estimation and compensation module, a channel estimation module based on compressed sensing and a part of fast Fourier Transform demodulation module, the core of which is a partial fast Fourier transform demodulation module, and the output of the other two modules is used as the input of partial fast Fourier transform. The present invention improves the traditional OFDM demodulation method, adopts partial Fourier transform as a demodulation method for the first time, and can eliminate part of the Doppler spread in the demodulation process; by processing the Doppler spread twice, it can The influence of Doppler extension on the signal is reduced to a relatively low range, especially for fast-changing underwater acoustic channels, so it has higher processing performance for Doppler extension.

Description

technical field [0001] The invention relates to a processing method for Doppler expansion in a high-speed OFDM underwater acoustic communication receiver, and belongs to the technical field of underwater acoustic communication. Background technique [0002] With more and more frequent activities in the ocean, people have higher and higher requirements on the speed of underwater acoustic communication. Orthogonal Frequency Division Multiplexing (OFDM) has become the preferred technology for high-speed underwater acoustic communication due to its high frequency band utilization and low complexity. Compared with terrestrial radio channels, the available channel bandwidth of underwater acoustic channels is lower and the speed of underwater sound is not high (about 1500m / s). Even if there is a small relative motion between underwater moving targets, it will cause a large Doppler frequency shift, which will cause serious Inter-Carrier Interference (ICI) at the receiving end of th...

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Problems solved by technology

Compared with the previous two types of methods, this type of method has a better effect, but when the channel changes rapidly (such as the relative movement speed between transceivers is large), this method will lead to excessive Doppler residual, so after demodulation is also less effective

[0007] The effects of the above three types of prior art methods are not ideal, especially for high-speed OFDM underwater acoustic communication, there is a problem that the Doppler residual is too large. Therefore, how to improve the traditional Doppler extension processing method and make the Doppler extension Minimize the impact on the signal to reduce the inter-subcarrier interference in the OFDM system and improve the processing performance of the underwater acoustic communication receiver is a problem worth studying

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