in this paper, for the purpose of investigating horizontal sound propagation, based on the results obtained from practical measurements in the strait of hormoz and available data on sound speed variations at different depths, a comprehensive model for shallow water multipath underwater acoustic channel is presented. mathematical modeling of multipath effect is based on ray theory and the image ...

Orthogonal frequency-division-multiplexing (OFDM) has been actively pursued in underwater acoustic communications. However, OFDM is extremely sensitive to carrier frequency offset (CFO) which cause significant problems. The utilization and performance of traditional channel estimation are poor. Although underwater acoustic communication was recently the focus of research, literatures on joint i...

Underwater acoustic signal processing aims to reconstruct the shallow water acoustic channel from both direct arrival and delayed multipath reflections. This enables accurate acoustic communications in shallow water, such as between underwater autonomous vehicles (UAVs), which are essential for coastal surveillance and other applications. In this work, we take a previously implemented algorithm...

Correlated multi-paths may cause a biased bearing estimation in shallow water, so most existing methods make fully use of the multi-path nature and the underwater channel property to provide an unbiased bearing estimation. However, an imprecise knowledge of the underwater channel parameters or the array model mismatches will cause performance degradation, especially for the high-resolution meth...

In this paper, we proposed a novel receiver algorithm for coherent underwater acoustic communications. The proposed receiver is composed of three parts: (1) Doppler tracking and correction, (2) Time reversal channel estimation and combining, and (3) Joint iterative equalization and decoding (JIED). To reduce computational complexity and optimize the equalization algorithm, Time reversal (TR) ch...

Underwater wireless communication is quickly becoming a necessity for applications in ocean science, defense, and homeland security. Acoustics remains the only practical means of accomplishing long-range communication in the ocean. The acoustic communication channel is fraught with difficulties including limited available bandwidth, long delay-spread, time-variability, and Doppler spreading. Th...

An inspection of signal processing approach in order to estimate underwater network cardinalities is conducted in this research. A matter of key prominence for underwater network is its cardinality estimation as the number of active cardinalities varies several times due to numerous natural and artificial reasons due to harsh underwater circumstances. So, a proper estimation technique is mandat...

Orthogonal Frequency Division Multiplexing (OFDM) is a wideband modulation scheme that has recently gained attention for underwater acoustic communications. The benefits of OFDM include its ability to overcome long channel delay spreads through the use of a guard interval, its ability to transform a frequency selective channel into multiple frequency non-selective channels, and its relatively e...