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USID: ultrasonic backscatter communication for structural health monitoring
Publikationstyp
Conference Paper
Date Issued
2022-07
Sprache
English
Start Page
33
End Page
35
Citation
11th International Conference on Energy Autonomous Sensor Systems: 33-35 (EASS 2022)
Contribution to Conference
Scopus ID
Publisher
VDE Verlag
ISBN
978-3-8007-5897-5
978-3-8007-5896-8
Sensor networks are a game-changer for the continuous monitoring of civil infrastructure, potentially increasing lifetime while reducing maintenance costs. However, wire-and batteryless sensors are preferable for lower cost of deployment. Radio backscatter (e.g., RFID) can provide power to the sensor nodes and establish a communication channel for data collection. However, radio frequencies can be challenging in certain environments, e.g., if sensors are underwater or shielded by metal. An RFID-like communication relying on acoustic waves through the structure is an attractive alternative, especially since many structural health monitoring (SHM) methods already require ultrasonic transducers that can be reused for communication and power. This work investigates passive communication through acoustic guided-wave metal channels, which are challenging because of the strong dependence of the signal-to-noise ratio on frequency, and strong multipath characteristics of the structural channel. To tackle these challenges, we show custom hardware for a USID tag and reader that can • choose the optimal carrier frequency for every channel on the fly, • employ higher-order load modulation in contrast to just binary modulation, • select the optimal load impedances for maximal SNR at the tag, and • demodulate the received signal analogously with lower power requirements compared to off-the-shelf solutions Furthermore, we developed a protocol for selecting the ideal carrier frequency for each channel at the reader, optimal constellation points at the tag, and channel estimation to mitigate inter-symbol-interference (ISI) through multipath propagation. The resulting acoustic backscatter communication system can reach more than 1.2 kbit/s data rate at distances up to 3 meters through guided-wave metal channels, where higher-order modulation achieves a significant increase in achievable data rates in all channels.
DDC Class
530: Physics
004: Computer Sciences