# How Many Antennas Do We Need for Massive MIMO Channel Sounding? - Validating Through Measurement

## TL;DR

This study evaluates how the number and configuration of antennas affect the accuracy of channel parameter estimation in massive MIMO systems at 3.5 GHz, using measurements and the SAGE algorithm across different environments.

## Contribution

It provides empirical validation of antenna array configurations and parameter estimation accuracy for outdoor massive MIMO channel sounding.

## Key findings

- Estimation errors vary with the number of antennas and environment.
- Optimal antenna configurations improve parameter estimation accuracy.
- Measurement results guide practical antenna array design for massive MIMO.

## Abstract

This paper investigates the impact of the number of antennas (8 to 64) and the array configuration on massive MIMO channel parameters estimation for multiple propagation scenarios at 3.5 GHz. Different measurement environments are artificially created by placing several reflectors and absorbers in an anechoic chamber. Ground truth channel parameters, e.g, path angles, are obtained by geometry and trigonometric rules. Then, these are compared to the channel parameters extracted by the applying Space-Alternating Generalized Expectation-Maximization (SAGE) algorithm on the measurements. Overall, the estimation errors for various array configurations and the multiple environments are compared. This paper will help to determine the appropriate configuration of the antenna array and the parameter extraction algorithm for outdoor massive MIMO channel sounding campaigns.