Method for estimating pulse noise in OFDM (Orthogonal Frequency Domain Multiplexing) underwater acoustic communication system

Abstract

The invention discloses a method for estimating pulse noise in an OFDM (Orthogonal Frequency Domain Multiplexing) underwater acoustic communication system. At a receiving end, sparse estimation is performed on pulse noise on an OFDM signal in an underwater acoustic channel transmission process according to a frequency domain signal subjected to redundant Doppler frequency shift compensation, and frequency offset compensation is performed on the frequency domain signal subjected to the redundant Doppler frequency shift compensation with void subcarriers. Under the consideration of mutual interference between the pulse noise and a carrier frequency offset in underwater acoustic communication, compensation of the carrier frequency offset is added in an iteration process while the pulse noise is estimated with all subcarriers and a posteriori distribution under a framework of conventional sparse Bayesian learning, and the frequency domain signal subjected to the redundant Doppler frequency shift compensation and a measurement diagonal matrix for estimating the pulse noise are updated continuously in order to lower influences between the two types of interference. Moreover, the pulse noise is estimated by full utilization of all the subcarriers in the method, so that the spectrum efficiency and the performance of the communication system are improved.

Description

technical field [0001] The present invention relates to an impulse noise estimation technique, in particular to an impulse noise estimation method in an OFDM (Orthogonal Frequency Domain Multiplexing, Orthogonal Frequency Division Multiplexing) underwater acoustic communication system. Background technique [0002] Impulse noise is a common noise in communication systems. In systems such as power line communication, wireless communication, and graphics processing, the suppression of impulse noise is a popular research direction. Also in the field of underwater acoustic communication, pulse interference also exists on the underwater acoustic channel, such as thermal noise, waves in the sea, tweets of marine organisms, ship transportation, human construction in the ocean, etc. will all generate pulse noise. Impulse noise has the characteristics of short duration, large energy and randomness, which has a serious impact on the transmission and reception of acoustic signals, and ...

AI Technical Summary

Problems solved by technology

However, in the underwater acoustic communication system, the ICI is caused by the carrier frequency offset, and the estimation of the impulse noise in the frequency domain is bound to be disturbed; on the other hand, although the impulse noise is sparse in the time domain, it is The projection of FFT (FastFourierTransformation, Fast Fourier Transformation) will have a global impact on the demodulated signal, and will also reduce the correct estimation of the carrier frequency offset

Currently, there is no impulse noise estimation method that can avoid the interaction between impulse noise and ICI caused by carrier frequency offset

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