Channel Modelling and Estimation for Shallow Underwater Acoustic OFDM Communication via Simulation Platform

Abstract

The performance of underwater acoustic (UWA) communication is heavily dependent on channel estimation, which is predominantly researched by simulating UWA channels modelled in complex and dynamic underwater environments. In UWA channels modelling, the measurement-based approach provides an accurate method. However, acquirement of environment data and simulation processes are scenario-specific and thus not cost-effective. To overcome such restraints, this article proposes a comprehensive simulation platform that combines UWA channel modelling with orthogonal frequency division multiplexing (OFDM) channel estimation, allowing users to model UWA channels for different ocean environments and simulate channel estimation with configurable input parameters. Based on the simulation platform, three independent simulations are conducted to determine the impacts of receiving depth, sea bottom boundary, and sea surface boundary on channel estimation. The simulations show that UWA channel estimation is greatly affected by underwater environments. The effect can be mainly attributed to changing acoustic rays tracing which result in fluctuating time delay and amplitude. With 10 m receiving depth and flat sea bottom, the channel estimation achieves optimal performance. Further study indicates that the sea surface has stochastic effects on channel estimation. As the significant wave height (SWH) increases, the average performance of channel estimation shows improvements.

A study on unpredictable shallow water channel behavior by various multipath patterns and experimental data analysis

“…It is particularly severe in shallow water communication where strong surface and bottom reflections occur in the sea. Significant amount of signal loss happens due to volume attenuation, bottom loss, scattering and reflection (Alenka ,2011;Wang et al,2019). Multipath depiction in Figure 1 displays the shallow water channel bounded by top water surface and sea bottom guiding the trapped sound energy to propagate between projector (transmitter) and hydrophone (receiver).…”

Joint Compressed Sensing and Enhanced Whale Optimization Algorithm for Pilot Allocation in Underwater Acoustic OFDM Systems

“…To imitate the underwater communication environment more realistically, the BELLHOP ray model [71]- [73] is employed to establish the UWA multipath channel with actual ocean data. The considered underwater region is in the South China Sea, located at a latitude and longitude of 24.2874 and 119.3469 degree, respectively.…”

Special Issue on Modelling, Simulation and Data Analysis in Acoustical Problems

“…In addition to HIFU, ultrasound waves are presented in several and various applications [7][8][9][10]. In particular, Choo et al proposes a method to estimate the soil depth based on elastic wave velocity.…”