Simulation of underwater communications with a colored noise approximation and mobility

Abstract

Abstract-We study the software simulation of underwater physical communications, namely, underwater acoustic waves and (de)modulation of underwater acoustic digital data signals. We take into account the mobility of nodes, such as in underwater sensor networks. We also consider the integration with protocol layers above the physical layer, i.e., the link and network layers. In this context, mobility is relevant because there are underwater vehicles and environmental conditions causing displacements of sensors. Attenuation is sensitive to transmitter-receiver separation distances. Because of mobility, distances change. Our solution is based on the work of Borrowski (2010). The physical layer is modeled as Matlab functions. As a function of distance and frequency, our physical layer model takes into account attenuation and noise and their effects on a phase-shift keyed signal. We use OMNeT++ to model link and network layer protocols. The Matlab functions and OMNet++ models are linked together. While Matlab does particularly well with signal processing, OMNeT++ addresses better the protocols placed in the link layer and above.

A Robust Algorithm for Estimation and Compensation of Doppler Shift in Underwater Acoustic OFDM Communication Systems

“…Second is the conversion of acoustic energy to heat energy, which is dependent on frequency. These two reasons are considered in Thorp's model [14]. Also, the absorption coefficient has a complicated dependence on frequency.…”

“…For this reason, ambient noise from four sources is considered separately and summed up. The equation that approximates all four noises in is not considered because it is too optimistic (uses a no wave, no wind assumption) [14]. The model, along with a model of ambient ocean noise used in this project to characterize the channel, is discussed in [16].…”

Simulation of Mobile Hydroacoustic Communications in Underwater Acoustic Sensor Networks

“…a represents the absorption coefficient. a(f ) is a frequency-dependent absorption coefficient(in dB/km) [13,14]:…”

“…The physical layer is simulated using MATLAB functions. The link and network layers are simulated using OMNeT++ (see Figure 4.1) [14].…”

Simulation and Modeling of Underwater Acoustic Communication Channels With Wide Band Attenuation and Ambient Noise

“…The low-pass filter has a profile similar to the profile of the underwater colored ambient noise. More details can be found in Reference [6].…”