Channel Measurement for Holographic MIMO: Benefits and Challenges of Spatial Oversampling

TL;DR

This paper experimentally demonstrates that spatial oversampling in holographic MIMO systems can significantly boost wireless capacity, but antenna efficiency remains a key challenge, and proposes an extended channel model accounting for environmental and antenna factors.

Contribution

It provides the first experimental evidence of capacity gains from spatial oversampling in holographic MIMO and introduces an extended EM-compliant channel model considering various physical effects.

Findings

Spatial oversampling increases system capacity.

Antenna efficiency limits capacity gains.

Extended channel model accounts for environmental and antenna effects.

Abstract

In this paper, the channel of an indoor holographic multiple-input multiple-output (MIMO) system is measured. It is demonstrated through experiments for the first time that the spatial oversampling of holographic MIMO systems is able to increase the capacity of a wireless communication system significantly. However, the antenna efficiency is the most crucial challenge preventing us from getting the capacity improvement. An extended EM-compliant channel model is also proposed for holographic MIMO systems, which is able to take the non-isotropic characteristics of the propagation environment, the antenna pattern distortion, the antenna efficiency, and the polarization characteristics into consideration.