On the Required Number of Antennas in a Point-to-Point Large-but-Finite MIMO System: Outage-Limited Scenario

TL;DR

This paper analyzes the minimum number of antennas needed in large but finite MIMO systems to meet outage constraints, considering various fading conditions and HARQ feedback, with derived asymptotic performance expressions.

Contribution

It provides new analytical expressions for antenna requirements and performance in finite MIMO systems, including effects of HARQ and power amplifier efficiency.

Findings

Few antennas suffice to meet outage constraints.

Asymptotic performance expressions are derived for large antenna numbers.

Power amplifier efficiency impacts MIMO-HARQ system performance.

Abstract

This paper investigates the performance of the point-to-point multiple-input-multiple-output (MIMO) systems in the presence of a large but finite numbers of antennas at the transmitters and/or receivers. Considering the cases with and without hybrid automatic repeat request (HARQ) feedback, we determine the minimum numbers of the transmit/receive antennas which are required to satisfy different outage probability constraints. Our results are obtained for different fading conditions and the effect of the power amplifiers efficiency on the performance of the MIMO-HARQ systems is analyzed. Moreover, we derive closed-form expressions for the asymptotic performance of the MIMO-HARQ systems when the number of antennas increases. Our analytical and numerical results show that different outage requirements can be satisfied with relatively few transmit/receive antennas.