Steady Channel Equalization Technology Of Complex Underwater Acoustic Communication

In recent years,underwater acoustic communication has become the focus of international research.However,the complex properties of underwater acoustic channels make it full of challenge to achieve high speed,long distance and high reliability communication.The adaptive decision feedback equalization(A-DFE)can address the problem of the underwater communication over a time-varing multipath channel in presence of worse intersymbol interference(ISI).The paper models the complex acoustic channels based on its physical properties and the ray theory.Then,a kind of A-DFE is studies,which can address the ISI.In this framework,the paper gives the multichannel decision feedback equalization(AM-DFE),which can be better adapt to the complex underwater environment and improve the equalizer's performance.This structure improves the received signal-noise ratio,reduces the symbol error rate,and ensure the stability of the communication system.In the fast time-varing channels,adopt the phase locked loop technology to overcome the phase rotation.On the base of the traditional sound pressure adaptive decision feedback equalization,we combine the vector hydrophone and adaptive decision feedback equalization.The paper presents two kinds of structures of the vector adaptive decision feedback equalization making full use of the sound pressure and three vibration velocity information.Combining vector hydrophone with the DFE can improve the performance of the system without increasing project complexity.Finally,according to the theory,the paper presents the simulations and experiments.The anti multipath ability of AM-DFE,combining with the spatial diversity and phase locked loop,and the performance of the vector decision feedback equalization have been validated.