Van Atta Acoustic Backscatter Node for Long-Range Underwater Links
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Solution Overview
Problem
Underwater backscatter communication systems are limited by the spherical spreading of backscattered signals, resulting in short communication ranges of few to tens of meters, making it difficult to deploy these systems at scale.
Innovation Solution
A retroreflective underwater backscatter node with a receiver, reflector, and modulator that uses Van Atta unit cells to retrodirect acoustic signals, controlling the direction of propagation through phase manipulation and impedance matching, enabling long-range communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional backscatter communication is used, then the system achieves low cost and low power consumption, but the communication range is limited to few to tens of meters due to spherical spreading
Solution Approach 1:
The patent divides the backscatter node into multiple independently controllable acoustic transducers arranged in an array. Each transducer can be individually phase-controlled to achieve beamforming, segmenting the signal transmission to counteract spherical spreading and extend communication range while maintaining low power operation.
Solution Approach 2:
The patent transitions from omnidirectional backscatter to directional beamforming by introducing spatial dimensionality control through phase manipulation of multiple transducers. This dimensional control allows the system to focus acoustic energy in specific directions, extending effective communication range without increasing overall power consumption.
2Adaptability or versatility
If backscatter nodes reflect signals in all directions, then the system achieves simple omnidirectional communication, but the signal strength diminishes rapidly due to spherical spreading
Solution Approach 1:
The patent implements dynamic phase control of acoustic transducers to adaptively steer acoustic beams in different directions. This dynamic control allows the system to maintain signal strength by focusing energy where needed while preserving angular coverage through electronic beam steering, eliminating the need for fixed omnidirectional reflection.
Solution Approach 2:
The patent changes the phase parameters of individual acoustic transducers to control the direction and focus of backscattered signals. By manipulating phase parameters dynamically, the system achieves both directional signal concentration (reducing spherical spreading loss) and wide angular coverage through electronic beamforming.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves ultra-low-power, long-range underwater networking with wide angular coverage, boosting communication range by an order of magnitude over existing designs and maintaining high signal-to-noise ratio.
Implementation Method 1
a retroreflective underwater backscatter node includes a receiver configured to receive an incoming acoustic signal from a certain direction; a reflector that reflects an incoming acoustic signal
Implementation Method 2
controlling the direction of propagation through phase manipulation and impedance matching
Implementation Method 3
the retroreflective underwater backscatter node retro-directs the incoming signal so that the incoming and back-scattered acoustic signals generally propagate along the same but opposite directions
Implementation Method 4
To communicate data, the backscatter node modulates its reflection coefficient, which allows a receiving hydrophone to sense changes in reflections and use them to decode the node's messages
Data Source
AI summary
Described herein is a retroreflective underwater backscatter node comprising a receiver that receives an incoming acoustic signal from a first direction; a reflector that reflects back an incoming acoustic signal in a second direction; and a modulator coupled to the reflector to modulate the reflected incoming acoustic signal as a back-scattered signal. In some embodiments, the first direction and second direction are substantially the same such that the retroreflective underwater backscatter node retro-directs an incoming acoustic signal as a back-scattered signal and incoming and back-scattered acoustic signals propagate in the same but substantially opposite directions.