Optimizing multi-user indoor sound communications with acoustic reconfigurable metasurfaces

TL;DR

This paper demonstrates how acoustic reconfigurable metasurfaces can be used to optimize multi-user indoor sound communication by shaping wavefields, reducing cross-talk, and increasing channel capacity in complex environments.

Contribution

It introduces a novel application of reconfigurable metasurfaces with optimization protocols to enhance indoor acoustic communication by wavefield shaping.

Findings

Achieved acoustic channel isolation and increased Shannon capacity.

Demonstrated multi-channel and multi-spectral acoustic functionalities.

Showed wavefield shaping can mitigate complex indoor sound scattering.

Abstract

Sound in indoor spaces forms a complex wavefield due to multiple scattering encountered by the sound. Indoor acoustic communication involving multiple sources and receivers thus inevitably suffers from cross-talks. Here, we demonstrate the isolation of acoustic communication channels in a room by wavefield shaping using acoustic reconfigurable metasurfaces (ARMs) controlled by optimization protocols based on communication theories. The ARMs have 200 electrically switchable units, each selectively offering 0 or {\pi} phase shifts in the reflected waves. The sound field is reshaped for maximal Shannon capacity and minimal cross-talk simultaneously. We demonstrate diverse acoustic functionalities over a spectrum much larger than the coherence bandwidth of the room, including multi-channel, multi-spectral channel isolations, and frequency-multiplexed acoustic communication. Our work shows that wavefield shaping in complex media can offer new strategies for future acoustic engineering.