Towards Very Large Aperture Massive MIMO: a measurement based study

TL;DR

This study provides empirical measurements of Massive MIMO channels in a large indoor environment, demonstrating how array aperture and user proximity influence system performance and channel resolvability.

Contribution

It presents the first extensive measurement-based analysis of Massive MIMO channels focusing on array aperture effects and user proximity in practical indoor scenarios.

Findings

Larger array aperture improves performance, especially in crowded scenarios.

User hand grip significantly affects channel resolvability.

Line-of-sight conditions can enhance propagation and system performance.

Abstract

Massive MIMO is a new technique for wireless communications that claims to offer very high system throughput and energy efficiency in multi-user scenarios. The cost is to add a very large number of antennas at the base station. Theoretical research has probed these benefits, but very few measurements have showed the potential of Massive MIMO in practice. We investigate the properties of measured Massive MIMO channels in a large indoor venue. We describe a measurement campaign using 3 arrays having different shape and aperture, with 64 antennas and 8 users with 2 antennas each. We focus on the impact of the array aperture which is the main limiting factor in the degrees of freedom available in the multiple antenna channel. We find that performance is improved as the aperture increases, with an impact mostly visible in crowded scenarios where the users are closely spaced. We also test MIMO capability within a same user device with user proximity effect. We see a good channel resolvability with confirmation of the strong effect of the user hand grip. At last, we highlight that propagation conditions where line-of-sight is dominant can be favorable.