Modeling And Parameter Estimation Of Underwater Acoustic Channels With Spatiotemporal Variations

Whether on land or in the ocean,signal transmission cannot be separated from channels.Underwater acoustic channels are more complex than terrestrial wireless channels,so many classic terrestrial wireless channel technologies cannot be directly used for underwater acoustic channels.Underwater acoustic channels face various problems,including severe Doppler and multipath effects,which can have an impact on channel modeling and parameter estimation.In order to address these issues,this article considers the physical characteristics of underwater acoustic channels and studies the spatiotemporal variation of underwater acoustic channels from two aspects: channel modeling and parameter estimation.In the aspect of channel modeling,first introduce the theory of ray acoustics and use BELLHOP to calculate the underwater acoustic channel.Analyzed the causes of Doppler effect in underwater acoustic channels and the characteristics of multi-scale and multi delay in underwater acoustic channels,and established a spatiotemporal variation underwater acoustic channel model using the Vir TEX algorithm.A spatiotemporal variation underwater acoustic channel model was established for the motion of sound sources in both calm and undulating environments.The commonly used active sonar emission signals were studied,and the received signals transmitted through spatiotemporal variation underwater acoustic channels were analyzed.Research channel estimation algorithms based on obtaining transmitted and received signals.In the aspect of channel estimation,the cross correlation algorithm and the least square algorithm are studied and analyzed.On this basis,the orthogonal Matching pursuit algorithm is studied.The influence of Doppler effect on channel estimation is analyzed,and the influence of transmitted signal parameters on the estimation performance of orthogonal Matching pursuit algorithm is discussed.Aiming at the computational complexity of orthogonal Matching pursuit algorithm,the time domain improved algorithm of orthogonal Matching pursuit is studied;Aiming at the problem of delay resolution of orthogonal Matching pursuit algorithm,the frequency domain improved algorithm of orthogonal Matching pursuit is studied.In order to verify the practicability of different algorithms,experiments were carried out in different working conditions of the pool,Songhua Lake and Qiandao Lake respectively,and the estimation results of the cross-correlation algorithm,the classical orthogonal Matching pursuit algorithm and the frequency domain improved orthogonal Matching pursuit algorithm were compared.The simulation and experimental results show that the frequency domain improved orthogonal Matching pursuit algorithm can better estimate the channel parameters of the main path,that is,achieve the tracking of space-time varying underwater acoustic channels.