A Low-cost and Flexible Underwater Platform to Promote Experiments in UWSN Research

Underwater acoustic sensor networks (UWSN) is a relatively new research area, and remains quite challenging due to limited bandwidth, low data rate, severe multipath, and high variability in the channel conditions. These complicated and non-linear channel characteristics render incorrect most simplifying assumptions used in simulations. We believe that, while researchers have proposed several novel protocols, their use of models and simulations as the only form of validation and intra-protocol comparison remains removed from reality. We argue that research experimentation is hindered by two fundamental constraints: high cost of underwater networking experiments, and lack of a single, easily-replicable platform for evaluation. We present here Underwater Platform to Promote Experimental Research (UPPER): a low-cost (about $25/node) and flexible underwater platform designed to enable cost-effective and repeatable experimentation. We utilize COTS components to provide a HW/SW integrated solution that interfaces our custom hydrophones ($5 ea.) with laptops that act as an SDR-based physical layer, while allowing higher layer protocols to interact via a plug-and-play interface. We show that our platform can communicate over small (5-10m) distances and over a range of data rates (100-600bps). We believe our platform removes the barrier to validating simulation results in underwater environments and also allowing a fair comparison with related protocols.