# Massive MIMO Radar for Target Detection

## TL;DR

This paper investigates the use of Massive MIMO technology in radar systems, demonstrating that increasing the number of antennas enhances target detection performance even without prior clutter knowledge.

## Contribution

It develops a robust Wald-type detection test for Massive MIMO radar and derives asymptotic detection performance expressions.

## Key findings

- Detection performance improves with more antennas.
- Performance guarantees hold regardless of clutter statistics.
- Asymptotic analysis matches finite system results.

## Abstract

Since the seminal paper by Marzetta from 2010, the Massive MIMO paradigm in communication systems has changed from being a theoretical scaled-up version of MIMO, with an infinite number of antennas, to a practical technology. Its key concepts have been adopted in the 5G new radio standard and base stations, where $64$ fully-digital transceivers have been commercially deployed. Motivated by these recent developments, this paper considers a co-located MIMO radar with $M_T$ transmitting and $M_R$ receiving antennas and explores the potential benefits of having a large number of virtual spatial antenna channels $N=M_TM_R$. Particularly, we focus on the target detection problem and develop a \textit{robust} Wald-type test that guarantees certain detection performance, regardless of the unknown statistical characterization of the clutter disturbance. Closed-form expressions for the probabilities of false alarm and detection are derived for the asymptotic regime $N\to \infty$. Numerical results are used to validate the asymptotic analysis in the finite system regime with different disturbance models. Our results imply that there always exists a sufficient number of antennas for which the performance requirements are satisfied, without any a-priori knowledge of the clutter statistics. This is referred to as the Massive MIMO regime of the radar system.