Can Massive MIMO Support URLLC?

TL;DR

This paper evaluates the potential of Massive MIMO systems to support ultra-reliable low-latency communication (URLLC), highlighting promising results in ideal conditions but challenges under standard 3GPP pilot configurations.

Contribution

It provides a comprehensive analysis of Massive MIMO's capability to meet URLLC requirements under different pilot schemes and channel models, using extensive simulations.

Findings

URLLC feasible with 128 antennas in ideal pilot settings

3GPP pilot constraints hinder URLLC performance

Massive MIMO shows promise but faces practical limitations

Abstract

We investigate the feasibility of using Massive MIMO to support URLLC in both coherence interval based and 3GPP compliant pilot settings. We consider grant-free uplink transmission with MMSE receiver and adopt 3GPP channel models. In the coherence interval based pilot setting, by extensive system level simulations, we find that using a Massive MIMO base station with 128 antennas and MMSE receiver, URLLC requirements can be achieved in Urban Macro (UMa) Non-Line of Sight (NLoS) with orthogonal pilots and Neyman-Pearson detector. However, in the 3GPP compliant pilot setting, even by using the covariance matrix of Physical Resource Block (PRB) subcarriers for active UE detection and channel estimation as well as open-loop power control, we find that URLLC requirements are still challenging to achieve due to the insufficient pilot length and pilot symbol location regulations in a PRB.