On the Ergodic Capacity for SIM-Aided Holographic MIMO Communications

TL;DR

This paper derives a tight, closed-form lower bound on the ergodic capacity of SIM-enhanced holographic MIMO systems, providing insights into system performance across all SNR levels.

Contribution

It introduces a novel analytical lower bound for ergodic capacity in SIM-aided HMIMO systems, valid for finite antennas and SIM elements, with extensive low-SNR analysis.

Findings

The bound is tight across all SNRs.

Key parameters significantly influence capacity.

Low-SNR analysis reveals system behavior insights.

Abstract

We derive a novel closed-form lower bound on the ergodic capacity of holographic multiple-input multiple-output (HMIMO) systems enhanced by stacked intelligent metasurfaces (SIMs) under Rayleigh fading conditions. The proposed expression is valid for systems with a finite number of antennas and SIM elements and exhibits tightness throughout the whole signal-to-noise ratio (SNR) range. Furthermore, we conduct a comprehensive low-SNR analysis, offering meaningful observations on how key system parameters influence the capacity performance.