Experimental Characterization of In-Pipe Acoustic Communication Channels Through Measurement of Pressure Transfer Functions

Communication systems based on in-pipe acoustic propagation have great potential to cover areas in which traditional infrastructure is unavailable. Characterization of the channel plays an important role in the design of any communication system. However, in case of spatially large channels, this aspect needs further investigations. In the present work, a method for the characterization of an acoustic channel is presented. This is based on the measurement of the complex transfer functions relating voltages and pressures at the channel ports. Such a technique was validated on a 75m long segment of a urban water distribution pipeline. The measurements assessed the frequency selectivity of the acoustic channel and the wave propagation speed. From experimental results, the response of the acoustic channel had an overall low-pass behavior, but it showed several deep notches at low frequency.