Humanitarian relief applications of underwater acoustic sensor networks

The highly-exposed live feed of the oil spill from underwater cameras in the Gulf of Mexico, and Tsunami Warning Systems are only two of many examples showcasing the potential of underwater sensor networks in fields such as underwater surveillance, undersea exploration, video-assisted navigation and environmental monitoring. However, underwater networks require much higher data rates than currently available with acoustic technology and more flexible protocol design to accommodate heterogeneous traffic demands in terms of bandwidth, delay, and end-to-end reliability. In this talk, we outline our current research efforts to assess the potential of multiple-input-multiple- output (MIMO) transmission techniques on acoustic networking. In particular, we will illustrate the multiplexing and diversity tradeoffs of underwater MIMO links. We will consequently characterize how the fundamental MIMO tradeoff translates into a tradeoff between transmission rate and link error probability and identify how the capabilities of MIMO links impact the design of higher layer protocols. We will then present the design of a class of medium access control and crosslayer routing protocols that adapt their behavior by optimally jointly selecting the transmit power, MIMO transmission mode, code length, and routes to minimize energy consumption while complying with application requirements.