Optimal User Loading in Massive MIMO Systems with Regularized Zero Forcing Precoding

TL;DR

This paper analyzes the asymptotic behavior of SLNR in massive MIMO systems with RZF precoding, optimizing user loading for spectral efficiency across different SNR regimes.

Contribution

It derives the asymptotic SLNR for large-scale MIMO systems and identifies optimal user loading strategies depending on SNR levels.

Findings

Optimal user loading varies with SNR.

SLNR asymptotically equals SINR in large systems.

User loading is one in low and high SNR regimes.

Abstract

We consider a downlink multiuser multiple-input multiple output (MIMO) system employing regularized zero-forcing (RZF) precoding. We derive the asymptotic signal-to-leakage-plus-noise ratio (SLNR) as both the number of antennas and the number of users go to infinity at a fixed ratio. Focusing on the symmetric uncorrelated channels, we show that the SLNR is asymptotically equal to signal-to-interference-plus-noise ratio (SINR) which allows us to optimize the user loading for spectral efficiency. The results show that the optimal user loading varies depending on the channel signal-to-noise ratio (SNR) but is equal to one in both the low or high SNR regimes.