Enabling Underwater Acoustic Cooperative MIMO Systems by Metamaterial-Enhanced Magnetic Induction

Abstract

The acoustic cooperative multi-input-multi-output (MIMO) systems equipped on the underwater robot swarms (URSs) can enable long-range and high-throughput communications. However, the acoustic communications cannot provide the real-time and accurate synchronization for the distributed transmitters of the cooperative MIMO due to the large delay of acoustic channels. In addition, the narrow bandwidth of the acoustic channel further enlarges the synchronization time and errors. In this paper, we propose the metamaterial magnetic induction (M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I)-assisted acoustic cooperative MIMO to address aforementioned challenges. The synchronization time can be reduced since the M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I has negligible signal propagation delays. To quantitatively analyze the improvement, we deduce the synchronization errors, signal-to-noise ratio (SNR), effective communication time, and the throughput of the system. Finally, the improvement of using M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I-assisted synchronization is validated by the numerical evaluation.