Trade-Offs in Decentralized Gigantic MIMO with Hard-Boundary Constraints

2026-06-30

AI Summary

This work addresses the challenges of high computational complexity and limited interconnect bandwidth in massive MIMO systems operating in the FR3 band for 6G, particularly under hard boundary constraints that hinder efficient decentralized architectures. The study extends, for the first time, the WAX decomposition framework to massive MIMO scenarios incorporating such hard constraints and proposes a decentralized signal processing scheme based on non-cooperative hardware modules. This approach is compatible with existing multi-antenna baseband units and achieves a substantial reduction in system complexity while effectively balancing performance against resource limitations. The results demonstrate the feasibility and practical potential of the proposed method for real-world deployment in next-generation wireless networks.

Abstract

To maintain the antenna apertures offered by 5G massive MIMO systems operating at the sub-6GHz band, known as FR1, 6G base stations (BSs) using the upper-mid band, FR3, should increase the number of antennas by a factor 4-8, giving rise to gigantic MIMO. This poses challenges in terms of processing complexity and interconnection bandwidth. The WAX framework, previously introduced for exploring trade-offs in decentralized architectures, may offer the flexibility needed to tackle these challenges. However, no results have been established on the applicability of this framework in the presence of hard-boundary constraints. The current work explores gigantic MIMO implementations based on a novel adaptation of the WAX framework, where the decentralized processing is performed by non-cooperating hardware modules. These modules may be implemented through state-of-the-art massive MIMO baseband units (BBUs). The results show the potential of the proposed framework towards exploiting trade-offs between complexity and performance in practical gigantic MIMO implementations.

Problem

• gigantic MIMO
• decentralized architecture
• hard-boundary constraints
• processing complexity
• interconnection bandwidth

Innovation

• gigantic MIMO
• decentralized architecture
• WAX framework
• hard-boundary constraints
• baseband units