State of the Art on Stacked Intelligent Metasurfaces: Communication, Sensing and Computing in the Wave Domain

TL;DR

This paper surveys stacked intelligent metasurfaces (SIM), a wave-domain platform built from multiple reconfigurable metasurface layers that can perform communications, sensing, and computing with lower power than fully-digital neural networks. It aggregates the state-of-the-art across beamforming design, channel estimation, direction-of-arrival estimation, integrated sensing and communications, semantic communications, electromagnetic modeling, and experimental evaluation to map progress and gaps. The review highlights a strong focus on beamforming and optimization, while wave-domain processing, EM realism, and hardware validation require further development. By outlining open research questions and practical challenges, the work emphasizes SIM's potential to enable multifunction wireless systems through energy-efficient, wave-based computation and processing.

Abstract

Stacked intelligent metasurface (SIM) is an emerging technology that capitalizes on reconfigurable metasurfaces for several applications in wireless communications. SIM is considered an enabler for integrating communication, sensing and computing in a unique platform. In this paper, we offer a survey on the state of the art of SIM for wireless communications.