Stacked Flexible Intelligent Metasurface Design for Multi-User Wireless Communications

TL;DR

This paper introduces a novel stacked flexible intelligent metasurface system for wireless communications, demonstrating significant performance improvements over rigid metasurfaces through an optimization framework.

Contribution

It is the first to propose a deformable, layered metasurface system for enhanced wireless communication performance.

Findings

Significant system sum rate improvements with SFIM.

Effective optimization framework for deformable metasurfaces.

Validation through simulation results.

Abstract

Stacked intelligent metasurfaces (SIMs) have recently emerged as an effective solution for next-generation wireless networks. A SIM comprises multiple metasurface layers that enable signal processing directly in the wave domain. Moreover, recent advances in flexible metamaterials have highlighted the potential of flexible intelligent metasurfaces (FIMs), which can be physically morphed to enhance communication performance. In this paper, we propose a stacked flexible intelligent metasurface (SFIM)-based communication system for the first time, where each metasurface layer is deformable to improve the system's performance. We first present the system model, including the transmit and receive signal models as well as the channel model, and then formulate an optimization problem to maximize the system sum rate under constraints on the transmit power budget, morphing distance, and the unit-modulus condition of the meta-atom responses. To solve this problem, we develop an alternating optimization framework based on the gradient projection method. Simulation results demonstrate that the proposed SFIM-based system achieves significant performance gains compared to its rigid SIM counterpart.