Implementation of an Underwater Acoustic Communication System and Performance Evaluation of Digital Modulations over a Water Pipeline

In this paper¡ an acoustic data communication system has been implemented in order to establish a data link between two distinct water stations through the water pipes.
For this purpose¡ channel characterization is necessary. Hence¡ Channel estimation has been done by Chirp probe signal. Then¡ suitable frequency band is selected through the channel frequency response.
Also¡ the best framing has been achieved by the assistance of the channel impulse response. In this paper¡ we have utilized robust modulation techniques in water environment such as Q-PSK¡ CP-FSK and CP-CSK. In Q-PSK case¡ linear equalizer has been used to compensate channel effects. In practical experiments¡ the frequency band and the symbol rate have been considered to be 16.8 – 31.2 KHz and 8303 symbols per second. Acoustic projector and hydrophone have been used to transmit and receive signal over the water-pipe channel. The generation of the transmission signal and the processing of the received signal are handled by MATLAB software. Practical results have been shown that in this setup with two variant Debi¡ the purpose of data transmission over a water pipeline is feasible.