Massive MIMO versus Small-Cell Systems: Spectral and Energy Efficiency Comparison

TL;DR

This paper compares the spectral and energy efficiency of massive MIMO and small-cell systems in 5G networks using stochastic geometry and large-system analysis, providing insights for optimal network design.

Contribution

It introduces a comparative model for M-MIMO and small-cell systems using Poisson point processes and analytical tools to evaluate their performance in different scenarios.

Findings

Small-cell densification favors user-average spectral efficiency in crowded areas.

Massive MIMO performs better in low user density environments.

Small-cell systems are more energy-efficient across all tested scenarios.

Abstract

In this paper, we study the downlink performance of two important 5G network architectures, i.e. massive multiple-input multiple-output (M-MIMO) and small-cell densification. We propose a comparative modeling for the two systems, where the user and antenna/base station (BS) locations are distributed according to Poisson point processes (PPPs). We then leverage both the stochastic geometry results and large-system analytical tool to study the SIR distribution and the average Shannon and outage rates of each network. By comparing these results, we observe that for user-average spectral efficiency, small-cell densification is favorable in crowded areas with moderate to high user density and massive MIMO with low user density. However, small-cell systems outperform M-MIMO in all cases when the performance metric is the energy efficiency. The results of this paper are useful for the optimal design of practical 5G networks.