Linear Massive MIMO Precoders in the Presence of Phase Noise -- A Large-Scale Analysis

TL;DR

This paper analyzes how phase noise affects the downlink performance of massive MIMO systems with large antenna arrays, revealing that oscillator configurations significantly impact SINR and system robustness.

Contribution

It provides a large-scale asymptotic analysis of phase noise effects on precoders in massive MIMO, quantifying SINR degradation and comparing oscillator configurations.

Findings

Increasing the number of oscillators degrades SINR performance.

System performance depends on the ratio of antennas to users and oscillator configuration.

Analytical results are validated through Monte-Carlo simulations.

Abstract

We study the impact of phase noise on the downlink performance of a multi-user multiple-input multiple-output system, where the base station (BS) employs a large number of transmit antennas $M$. We consider a setup where the BS employs $M_{\mathrm{osc}}$ free-running oscillators, and $M/M_{\mathrm{osc}}$ antennas are connected to each oscillator. For this configuration, we analyze the impact of phase noise on the performance of the regularized zero-forcing (RZF), when $M$ and the number of users $K$ are asymptotically large, while the ratio $M/K=\beta$ is fixed. We analytically show that the impact of phase noise on the signal-to-interference-plus-noise ratio (SINR) can be quantified as an effective reduction in the quality of the channel state information available at the BS when compared to a system without phase noise. As a consequence, we observe that as $M_{\mathrm{osc}}$ increases, the SINR performance of all considered precoders degrades. On the other hand, the variance of the random phase variations caused by the BS oscillators reduces with increasing $M_{\mathrm{osc}}$. Through Monte-Carlo simulations, we verify our analytical results, and compare the performance of the precoders for different phase noise and channel noise variances. For all considered precoders, we show that when $\beta$ is small, the performance of the setup where all BS antennas are connected to a single oscillator is superior to that of the setup where each BS antenna has its own oscillator. However, the opposite is true when $\beta$ is large and the signal-to-noise ratio at the users is low.