From Antenna Abundance to Antenna Intelligence in 6G Gigantic MIMO Systems

TL;DR

This paper proposes intelligent, non-uniform antenna array designs for 6G Massive MIMO systems, reducing hardware complexity while maintaining high spectral efficiency through adaptive, site-specific antenna placement.

Contribution

It introduces a paradigm shift from uniform to non-uniform, sparse antenna arrays, demonstrating improved performance with fewer antennas in future 6G Gigantic MIMO systems.

Findings

Non-uniform sparse arrays outperform uniform arrays in multiuser MIMO performance.

Adaptive antenna placement can significantly reduce hardware costs and power consumption.

Numerical results show improved sum rate with fewer antennas.

Abstract

Current cellular systems achieve high spectral efficiency through Massive MIMO, which leverages an abundance of antennas to create favorable propagation conditions for multiuser spatial multiplexing. Looking towards future networks, the extrapolation of this paradigm leads to systems with many hundreds of antennas per base station, raising concerns regarding hardware complexity, cost, and power consumption. This article suggests more intelligent array designs that reduce the need for excessive antenna numbers. We revisit classical uniform array design principles and explain how their uniform spatial sampling leads to unnecessary redundancies in practical deployment scenarios. By exploiting non-uniform sparse arrays with site-specific antenna placements -- based on either pre-optimized irregular arrays or real-time movable antennas -- we demonstrate how superior multiuser MIMO performance can be achieved with far fewer antennas. These principles are inspired by previous works on wireless localization. We explain and demonstrate numerically how these concepts can be adapted for communications to improve the average sum rate and similar metrics. The results suggest a paradigm shift for future antenna array design, where antenna intelligence replaces sheer antenna count. This opens new opportunities for efficient, adaptable, and sustainable Gigantic MIMO systems.