The prospect of an 'Underwater Internet' has raised significant interest among the general public because of its potential in facilitating many commercial, scientific, and military activities at sea. Still, in spite of the increased attention by the research community in the last few years, underwater networks are still in their infancy. Current state-of-the-art underwater acoustic technology can support mostly point-to-point, low-data-rate, and delay-tolerant applications. This project is attempting to advance the state of the art in underwater networking by investigating two fundamental issues. First, it is developing technology to communicate over short-range links at higher transmission rates than available today. Second, it is developing technology to integrate the newly-designed acoustic communication technology with the Internet to guarantee interoperability with existing networks. The new capabilities will be demonstrated by focusing on video streaming application scenarios for underwater surveillance. The project will integrate research and education by establishing cross-listed graduate/undergraduate courses on acoustic networking and its applications, activities to reach out to underrepresented communities, and pursuit of technology transfer activities in this field.
The project proposes a paradigm shift in how information is carried over short-range acoustic links, by developing novel carrierless transmission and multiple access techniques. Short, properly designed/shaped pulses are transmitted in the ultrasonic spectral regime following an adaptive time-hopping pattern with a superimposed spreading code of variable length. The effect is nearly seamless physical/MAC layer integration, and potential for highest data rate communication by properly optimized spreading sequences. Secondary -yet important- benefits of the proposed approach are low cost and weight oscillator-free transducers and excellent receiver interference suppressing capabilities. Integration with the Internet is being pursued by means of an adaptation layer that acts as an interface between higher-layer protocols and the underwater links by performing header compression, packet fragmentation, and creation of a virtual common broadcast space.
