BatNet: Data transmission between smartphones over ultrasound
This addresses the need for censorship-resistant mesh networks, though it is incremental as it builds on existing ultrasonic communication methods.
The paper tackles the problem of enabling data transmission between smartphones using ultrasound signals, achieving a rate of over 600 bit/s up to 6 meters with phase shift keying.
In this paper, we present BatNet, a data transmission mechanism using ultrasound signals over the built-in speakers and microphones of smartphones. Using phase shift keying with an 8-point constellation and frequencies between 20--24kHz, it can transmit data at over 600bit/s up to 6m. The target application is a censorship-resistant mesh network. We also evaluated it for Covid contact tracing but concluded that in this application ultrasonic communications do not appear to offer enough advantage over Bluetooth Low Energy to be worth further development.