Impact of Frequency Selectivity on the Information Rate Performance of CFO Impaired Single-Carrier Massive MU-MIMO Uplink

TL;DR

This paper investigates how frequency-selectivity influences the power requirements in massive MU-MIMO uplink systems with residual CFO, revealing that higher frequency-selectivity reduces the power gap and still allows significant array gains.

Contribution

It provides an information-theoretic analysis of the impact of frequency-selectivity on power gap and array gains in CFO-impaired massive MU-MIMO uplink systems.

Findings

Frequency-selectivity reduces the power gap between residual and ideal CFO scenarios.

An $ ext{O}(\sqrt{M})$ array gain is achievable despite residual CFO and channel estimation errors.

The power gap decreases as channel frequency-selectivity increases.

Abstract

In this paper, we study the impact of frequency-selectivity on the gap between the required per-user transmit power in the residual CFO scenario (i.e. after CFO estimation/compensation at the base-station (BS) from [6]) and that in the ideal/zero CFO scenario, for a fixed per-user information rate, in single-carrier massive MU-MIMO uplink systems with the TR-MRC receiver. Information theoretic analysis reveals that this gap decreases with increasing frequency-selectivity of the channel. Also, in the residual CFO scenario, an $\mathcal{O}(\sqrt{M})$ array gain is still achievable ($M$ is the number of BS antennas) in frequency-selective channels with imperfect channel estimates.