Ultra-Wideband Underwater Backscatter via Piezoelectric Metamaterials
We present the design, implementation, and evaluation of 𝑈2𝐵, a technology that enables ultra-wideband backscatter in underwater environments. At the core of 𝑈2𝐵’s design is a novel metamaterial inspired transducer for underwater backscatter, and algorithms that enable self-interference cancellation and FDMA-based medium access control. We fabricated 𝑈2𝐵 nodes and tested them in a river across different weather conditions, including snow and rain. Our empirical evaluation demonstrates that 𝑈2𝐵 can achieve throughputs up to 20 kbps, an operational range up to 62 m, and can scale to networks with more than 10 nodes. In comparison to the state-of-the-art system for underwater backscatter, our design achieves 5× more throughput and 6× more communication range. Moreover, our evaluation represents the first experimental validation of underwater backscatter in the wild.