This paper describes experiments in using audible sound as a means
for wireless device communications. The direct application of
standard modulation techniques to sound, without further
improvements, results in sounds that are immediately perceived as
digital communications and that are fairly aggressive and
intrusive. We observe that some parameters of the modulation that
have an impact in the data rate, the error probability and the
computational overhead at the receiver also have a tremendous
impact in the quality of the sound.
This paper focuses on how to vary those parameters in standard
modulation techniques such as ASK, FSK and Spread-Spec-trum to obtain
communication systems in which the messages are musical and other
familiar sounds, rather than modem sounds. A prototype called Digital
Voices demonstrates the feasibility of this music-based communication
technology. Our goal is to lay out the basis of sound design for
aerial acoustic communications so that the presence of such
communications, though noticeable, is not intrusive and can even be
considered as part of musical compositions and sound tracks.
