Massive MIMO with Imperfect Channel Covariance Information

TL;DR

This paper examines how imperfect covariance information affects massive MIMO uplink performance, proposing estimation schemes and showing that near-optimal spectral efficiency is achievable even with imperfect knowledge.

Contribution

It introduces two covariance matrix estimation schemes and derives a spectral efficiency lower bound under imperfect covariance knowledge.

Findings

Covariance information is not critical for high spectral efficiency.

Proposed estimation schemes effectively approximate covariance matrices.

Achieving near-ideal spectral efficiency is feasible with imperfect covariance data.

Abstract

This work investigates the impact of imperfect statistical information in the uplink of massive MIMO systems. In particular, we first show why covariance information is needed and then propose two schemes for covariance matrix estimation. A lower bound on the spectral efficiency (SE) of any combining scheme is derived, under imperfect covariance knowledge, and a closed-form expression is computed for maximum-ratio combin- ing. We show that having covariance information is not critical, but that it is relatively easy to acquire it and to achieve SE close to the ideal case of having perfect statistical information.