MFSK signal demodulation method and system under shallow sea impulse noise and multipath channel

Abstract

The invention belongs to the technical field of underwater acoustic communication signal demodulation, and particularly relates to an MFSK signal demodulation method and system under shallow sea impulse noise and a multipath channel, and the method comprises the steps: carrying out the impulse noise suppression preprocessing and carrier rough estimation of an MFSK receiving signal, obtaining M subcarrier rough estimation values, dividing the signal after the impulse noise suppression into M paths, and obtaining the baseband signal of each subcarrier through accurate estimation, carrier removal and carrier synchronization; performing timing estimation and timing synchronization on the baseband signal; and sampling each path of subcarrier signal by using the optimal sampling time to obtain M sampling values, and recovering original symbol information through selection judgment to complete MFSK signal demodulation. According to the method, the problems that under the conditions of shallow sea impulse noise and multipath channels, MFSK signal demodulation robustness is poor, performance is low, and complete and practical methods and systems capable of being used for engineering practice are lacked are solved, and good bit error rate performance can be achieved under the conditions of shallow sea impulse noise and underwater acoustic multipath channels.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustic communication signal demodulation, in particular to an MFSK signal demodulation method and system under shallow sea pulse noise and multi-channel channels. Background technique [0002] Multi-ary frequency shift keying (M-ary Frequency Shift Keying, MFSK) signals usually use non-coherent demodulation, which has the advantages of insensitivity to phase distortion and strong tolerance to Doppler frequency shift, and is widely used in In underwater acoustic communication system. In the field of underwater information monitoring and underwater acoustic countermeasures, it is often necessary to process underwater acoustic signals without relying on prior information or with little prior information, and the blind demodulation of underwater acoustic MFSK signals is an important content. [0003] The demodulation method for radio communication MFSK signal under additive Gaussian background n...

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Problems solved by technology

[0004] For this reason, the present invention provides a kind of MFSK signal demodulation method and system under shallow sea pulse noise and multi-channel channel, solves the poor robustness and low performance of MFSK signal demodulation under the conditions of shallow sea pulse noise and multi-channel channel, Lack of complete and practical methods and systems that can be used in engineering practice, etc., can have better bit error rate performance under shallow sea impulse noise and underwater acoustic multi-channel channels

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