Indoor Massive MIMO Deployments for Uniformly High Wireless Capacity

TL;DR

This paper introduces EDA-ZF, a practical interference mitigation method for indoor massive MIMO, demonstrating its effectiveness in providing uniform high capacity across users and analyzing the impact of network densification and coordination.

Contribution

The paper proposes a novel Eigen-direction-aware ZF method with partial coordination for indoor massive MIMO, offering a practical solution for uniform high wireless capacity.

Findings

EDA-ZF achieves uniformly good user rates in indoor environments.

Network densification without full coordination reduces performance.

NeMIMO benefits are significant under strong outdoor interference, especially for cell-edge users.

Abstract

Providing consistently high wireless capacity is becoming increasingly important to support the applications required by future digital enterprises. In this paper, we propose Eigen-direction-aware ZF (EDA-ZF) with partial coordination among base stations (BSs) and distributed interference suppression as a practical approach to achieve this objective. We compare our solution with Zero Forcing (ZF), entailing neither BS coordination or inter-cell interference mitigation, and Network MIMO (NeMIMO), where full BS coordination enables centralized inter-cell interference management. We also evaluate the performance of said schemes for three sub-6 GHz deployments with varying BS densities -- sparse, intermediate, and dense -- all with fixed total number of antennas and radiated power. Extensive simulations show that: (i) indoor massive MIMO implementing the proposed EDA-ZF provides uniformly good rates for all users; (ii) indoor network densification is detrimental unless full coordination is implemented; (iii) deploying NeMIMO pays off under strong outdoor interference, especially for cell-edge users.