Millimeter Wave Communications with Reconfigurable Antennas

TL;DR

This paper introduces a theoretical framework for millimeter wave MIMO systems with reconfigurable antennas, demonstrating throughput gains and proposing a low-complexity reconfiguration algorithm to enhance performance.

Contribution

It develops a new architecture and analytical model for reconfigurable mmWave MIMO, including a low-complexity algorithm for reconfiguration and beam selection.

Findings

Reconfigurable antennas improve throughput in mmWave MIMO.

Derived average throughput gain expression for reconfigurable antennas.

Proposed algorithm achieves near-optimal performance with low complexity.

Abstract

The highly sparse nature of propagation channels and the restricted use of radio frequency (RF) chains at transceivers limit the performance of millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems. Introducing reconfigurable antennas to mmWave can offer an additional degree of freedom on designing mmWave MIMO systems. This paper provides a theoretical framework for studying the mmWave MIMO with reconfigurable antennas. We present an architecture of reconfigurable mmWave MIMO with beamspace hybrid analog-digital beamformers and reconfigurable antennas at both the transmitter and the receiver. We show that employing reconfigurable antennas can provide throughput gain for the mmWave MIMO. We derive the expression for the average throughput gain of using reconfigurable antennas, and further simplify the expression by considering the case of large number of reconfiguration states. In addition, we propose a low-complexity algorithm for the reconfiguration state and beam selection, which achieves nearly the same throughput performance as the optimal selection of reconfiguration state and beams by exhaustive search.