Generalized spatial modulation for underwater backscatter communication using acoustic metasurfaces.

Design of a long-range, high data-rate and ultra low power underwater communications system is crucial for a variety of applications. However, this task is challenging because of the underwater channel dynamics, propagation characteristics and power constraints. Recently, the concept of acoustic metasurfaces (AMS) has emerged as a promising solution in underwater communications, due to its ability to manipulate wave transmission and reflection. Although the material properties of AMS have been extensively studied in the earlier literature, its applicability as a part of underwater communications has received little attention. In this work, we examine the suitability of an AMS as an underwater backscattering device to provide enhanced communication data rates. In particular, we propose an integration of generalized spatial modulation (GSM) with AMS to achieve high data rates over long ranges. Our simulation results, based on a practically relevant channel model, show significant improvements in the communication performance when the proposed technique is employed. Additionally, we discuss the advantages, challenges and open problems in employing AMS-assisted underwater communications with GSM, and present potential future research directions.