Experimental demonstration of spatial division multiplexing multiple-input/multiple-output underwater acoustic communication using a time-reversal method at the depth of the continental shelf: a consideration of optimization of signal length and number of transmission channels

Abstract

In this paper, the performance of the adaptive passive time-reversal method is investigated for an at-sea experiment of multiple-input/multiple-output underwater acoustic communication over a range of 13.5 km. The experiment was conducted at a depth of 200 m utilizing up to five transmitters with 4–8.5 kHz signal bandwidth for spatial division multiplexing. It was confirmed that the performance depends on the delay time from the timing of the channel response estimation to the communication signal reception, and the optimal signal length and the number of transmission channels can be determined according to the required bit error rate (BER) for the system. As a result, using the optimal signal length and a number of transmission channels, effective data rates of 30.21 and 37.53 kbps are achieved with BER ranges of less than 0.1% and 1%, respectively, with more than 90% of received communication signal packets.