2008 Volume E91.A Issue 7 Pages 1652-1658
This paper presents a technology for short-range communications using sound wave, in which the modulated data signal can be transmitted in parallel with regular audio without significantly degrading the quality of the sound. The technology, which we call Acoustic OFDM, replaces the high frequency band of the audio signal with OFDM carriers, each of which is power-controlled according to the spectrum envelope of the original audio signal. It can provide data transmission of several hundreds bps. The implemented Acoustic OFDM system enables the transmission of short text messages from loud speakers to mobile devices at a distance of around 3m.
