Underwater Backscatter Networking
Abstract
We propose Piezo-Acoustic Backscatter (PAB), the first technology that enables backscatter networking in underwater environments. PAB relies on the piezoelectric effect to enable underwater communication and sensing at near-zero power. Its architecture is inspired by radio backscatter which works well in air but cannot work well underwater due to the exponential attenuation ofradio signals in water. PAB nodes harvest energy from underwater acoustic signals using piezoelectric interfaces and communicate by modulating the piezoelectric impedance. Our design introduces innovations that enable concurrent multiple access through circuit-based frequency tuning of backscatter modulation and novel medium access techniques that exploit the properties of PAB nodes to deliver higher network throughput and decode network collisions. Our proposed contributions extend beyond communication; we introduce novel algorithms that leverage a network of underwater backscatter nodes to enable localization and self-navigation in challenging environments. We built an initial prototype of our design using custom-designed, mechanically fabricatedtransducers and a battery-free hardware implementation. Our initial results demonstrate single-link throughputs of multiple kilobits per second and power up ranges up to 10 m even when the sensor is completely battery-free. As part of this proposal, we plan to build PAB into a full end-to-end wireless communication system, scale it to multiple concurrent nodes (MU-MIMO), and extend it to deal with mobility. Our nodes will consist of general-purpose battery-free micro-computers with extensible sensing interfaces that can be used for a variety of underwater monitoring applications. We will test PAB in controlled and uncontrolled environments and demonstrate that it enables continuous, long-term, and battery-free underwater sensing, communication, and computing.If successful, the proposed research will deliver the first system that enables underwater backscatter networking. Such system can provide the Navy with unique and revolutionary capabilities. Its applications include ultra-long-term naval deployments, deep-sea localization and navigation, distributed and persistent sensing, and battery-free communication with UUVs and submarines. Combining this system with the underwater-to-air communication technology (TARF) from the ONR YIP proposal would enable a ubiquitous, distributed, efficient, and persistent communication system for ultra-long-term Naval deployments.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 17, 2020
- Source ID
- N000142012531
Entities
People
- Fadel Adib
Organizations
- Massachusetts Institute of Technology
- Office of Naval Research
- United States Navy