This paper presents a novel broadband modulation method for digital underwater communications: Chirp Slope Keying (CSK). In its simplest form, the binary information modulates the slope of a linear chirp, with up-chirps representing ones and down-chirps representing zeros. Performance evaluation in the form of probability of error vs. SNR show that the system performs as expected for AWGN envir...

Underwater acoustic communications, especially from a single point-to-point link perspective, have been studied extensively in the past few decades. Underwater networking issues have begun to attract the interest of researchers as well, and represent a fertile research area which can be expected to grow in the future. Bringing the study of acoustic communications systems to the networking level...

This paper discusses the use of distributed autonomous underwater vehicles (AUVs) for multistatic processing and tracking of underwater target. A localized processing chain is implemented on each AUV to generate the contact report of an underwater target that is transmitted to a command center via underwater acoustic communications (UWA). The contact reports from several AUVs are combined toget...

This report summarizes our research directions in underwater sensor networks. We highlight potential applications to off-shore oilfields for seismic monitoring, equipment monitoring, and underwater robotics. We identify research directions in short-range acoustic communications, MAC, time synchronization, and localization protocols for highlatency acoustic networks, long-duration network sleepi...

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges fo...

Sinusoidal Transform based Orthogonal Frequency Division Multiplexing (OFDM) is proposed for Underwater Acoustic Communications. Underwater acoustic channels are large delay spread channels. The sinusoidal transforms can be used as an alternative to the discrete Fourier transform (DFT) for OFDM wireless transmission with the added advantages of reduced implementation area, increased computation...

High cost of development and deployment coupled with the complexity of the underwater acoustic channel makes it important to develop simulation tools which can assist in investigating underwater sensor networks and mobile autonomous underwater vehicular communications. Some recent developments have led to simulators which provide the ability to simulate mobile and stationary underwater acoustic...

This paper describes a feasibility study that is included with the research, development and testing of a micro communications sonobuoy deployable by Maritime Fixed wing Unmanned Aerial Vehicles (M-UAV) and rotor wing Quad Copters which are both currently being developed by the University of Adelaide. The micro communications sonobuoy is developed to act as a seamless communication relay betwee...

In order to take measurements in space and time from the undersampled vast ocean, it is necessary to employ multiple autonomous underwater vehicles, such as gliders, that communicate and coordinate with each other. These vehicles need to form a team in a specific formation, steer through the 3D region of interest, and take application-dependent measurements such as temperature and salinity. In ...