Impact of Channel Aging on Zero-Forcing Precoding in Cell-Free Massive MIMO Systems

TL;DR

This paper investigates how channel aging, due to user mobility and phase noise, affects the spectral efficiency of zero-forcing precoding in cell-free massive MIMO systems, highlighting performance degradation caused by delays.

Contribution

It provides an analysis of channel aging effects on ZFP in cell-free mMIMO, considering both mobility and phase noise, which was not extensively studied before.

Findings

Channel aging significantly reduces spectral efficiency.

Mobility and phase noise both contribute to performance degradation.

Numerical results quantify the impact of aging effects.

Abstract

In the context of cell-free massive multi-input multi-output (mMIMO), zero-forcing precoding (ZFP) requires the exchange of instantaneous channel state information and precoded data symbols via a fronthaul network. It causes considerable propagation and processing delays, which degrade performance. This letter analyzes the impact of channel aging on the performance of ZFP in cell-free mMIMO. The aging effects of not only user mobility but also phase noise are considered. Numerical results in terms of per-user spectral efficiency are illustrated.