Networking Protocols, experimentation, at-sea trials. We are involved in several research activities for underwater networking. There, our focus is centered around the design of networking protocols and interfaces with commercial and prototype undersea devices. Various experimental activities are also on the way.
Challenges
Underwater networking poses serious challenges to network designers, as no straightforward translation exists between protocols for the terrestrial wireless radio environment and their underwater counterparts. The main reason behind this is the different nature of the underwater acoustic channel: long propagation delays (the average propagation speed of an acoustic wave is about 1500 m/s underwater, nearly 200’000 times smaller than radio waves in the air), strong multipath effects, long-term channel variations, and last but not least a much smaller bandwidth available (due to the use of acoustic frequencies, i.e., in the tens of kHz range), which turns into lower transmit bit rates. While radio and optical waves may also be an option for underwater communications, acoustic waves still foster a lot of interest, as they are currently the only means to reach distances longer than a few hundred meters. With the proper configuration of transmission hardware parameters, acoustic waves can travel up to tens of kilometers, making long range communication feasible, albeit at a possibly very low bit rate.
Channel modeling
As there is no widely agreed upon model for the channel, we seek new models that are sufficiently compact yet simple enough to be plugged into a network simulator. This activity is carried out in cooperation with institutions and research centers that can provide real data from undersea measurement campaigns.
Underwater acoustic channel can be simulated using ray-tracer as well. We develop the WOSS Framework to obtain realistic acustic channel realization based on ray-tracer to be used in underwater network simulators.
MAC protocol design and evaluation
We are currently analyzing a number of MAC solutions by means of simulations and stochastic models, in order to discover which features make one protocol perform better than others, with the final objective to create a novel protocol encompassing the best behaviors seen in other approaches.
Routing and broadcasting
Multihop underwater networks will require delay-tolerant routing protocols, that work well in the presence of very long propagation delays. We are currently analyzing the relevant routing tradeoffs that allow, e.g., to save energy by choosing wisely which nodes will relay messages. We are also designing efficient broadcasting techniques based on Hybrid ARQ.
Experimentation
We collaborate with research institutions to define joint sea trial activities which allow for network protocol evaluation as well as channel characterization; this feeds novel insight and provides directions to all above tasks.
Publications
Previous works can be found at this link
DESERT underwater simulator
DESERT Underwater is a complete set of public C++ libraries that extend the NS-MIRACLE simulator to support the design and implementation of underwater network protocols.
DESERT simulator
WOSS framework
WOSS is a multi-threaded C++ framework that permits the integration of any existing underwater channel simulator that expects environmental data as input and provides as output a channel realization. Currently, WOSS integrates the Bellhop ray-tracing program.
WOSS framework
Related projects
- EDA SALSA
- ONR research grant
- CLAM (CoLlAborative eMbedded networks for submarine surveillance, 2010-2013)
Collaborations
- CNR-INM, Genova, Italy
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The Hatter Department of Marine Technologies, University of Haifa, Israel
- Evologics GmbH, Germany
- NATO Centre for Maritime Research and Experimentation (CMRE)
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Naval Postgraduate School, Monterey, CA, USA
- Italian Ministry of Defense
- University of Twente, Enschede, The Nederlands
- University of Rome “La Sapienza”
Team Members
- Michele Zorzi
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Filippo Campagnaro
- Roberto Francescon
- Antonio Montanari
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Federico Favaro
- Federico Guerra