Two-way communication over gas pipe-line using multicarrier modulated sound waves with cyclic frequency shifting

Abstract

In recent years, several studies on acoustic communication systems utilizing gas pipe lines have been carried out. However, in conventional acoustic communication technology, the transmission rate cannot be improved because of the reverberant signals arising from reflections at the bends and branches in pipes. To reduce the effect of the reverberant signals and to improve the transmission data rate, we studied a multi-carrier modulation system. In this study, to avoid intersymbol interference, we employed special modulation symbols composed of multicarrier frequencies which change cyclically. To evaluate the proposed system, we constructed an experimental setup simulating a pipe system equivalent to that of a six-story building as a communication path. We achieved a transmission rate of 3,840 bps using the proposed method.