# Uplink Analysis of Large MU-MIMO Systems With Space-Constrained Arrays in Ricean Fading

## TL;DR

This paper derives closed-form approximations for the uplink SINR and spectral efficiency of large MU-MIMO systems with space-constrained arrays under Ricean fading, revealing performance saturation effects and the impact of LoS and correlation.

## Contribution

It provides novel analytical expressions for system performance considering unequal correlation and Rice factors with physical size constraints on the array.

## Key findings

- SINR saturates with increasing SNR and antennas due to array size limits
- Unequal correlation matrices can improve performance
- Strong LoS conditions can reduce spectral efficiency

## Abstract

Closed-form approximations to the expected per-terminal signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral efficiency of a large multiuser multiple-input multiple-output system are presented. Our analysis assumes correlated Ricean fading with maximum ratio combining on the uplink, where the base station (BS) is equipped with a uniform linear array (ULA) with physical size restrictions. Unlike previous studies, our model caters for the presence of unequal correlation matrices and unequal Rice factors for each terminal. As the number of BS antennas grows without bound, with a finite number of terminals, we derive the limiting expected per-terminal SINR and ergodic sum spectral efficiency of the system. Our findings suggest that with restrictions on the size of the ULA, the expected SINR saturates with increasing operating signal-to-noise-ratio (SNR) and BS antennas. Whilst unequal correlation matrices result in higher performance, the presence of strong line-of-sight (LoS) has an opposite effect. Our analysis accommodates changes in system dimensions, SNR, LoS levels, spatial correlation levels and variations in fixed physical spacings of the BS array.