Massive MIMO with Spatially Correlated Rician Fading Channels

TL;DR

This paper analyzes multi-cell Massive MIMO systems with spatially correlated Rician fading, deriving spectral efficiency expressions and showing MMSE channel estimation outperforms others as antenna count increases.

Contribution

It provides a comprehensive analysis of spectral efficiency in Massive MIMO with Rician fading, including new closed-form expressions and asymptotic behavior insights.

Findings

MMSE estimator yields higher spectral efficiency than EW-MMSE and LS.

Spectral efficiency increases with the number of antennas, especially with MMSE.

Closed-form UL and DL spectral efficiency expressions are derived for Rician channels.

Abstract

This paper considers multi-cell Massive MIMO (multiple-input multiple-output) systems where the channels are spatially correlated Rician fading. The channel model is composed of a deterministic line-of-sight (LoS) path and a stochastic non-line-of-sight (NLoS) component describing a practical spatially correlated multipath environment. We derive the statistical properties of the minimum mean squared error (MMSE), element-wise MMSE (EW-MMSE), and least-square (LS) channel estimates for this model. Using these estimates for maximum ratio (MR) combining and precoding, rigorous closed-form uplink (UL) and downlink (DL) spectral efficiency (SE) expressions are derived and analyzed. The asymptotic SE behavior when using the different channel estimators are also analyzed. Numerical results show that the SE is higher when using the MMSE estimator than the other estimators, and the performance gap increases with the number of antennas.