# Position Aided Beam Alignment for Millimeter Wave Backhaul Systems with Large Phased Arrays

## TL;DR

This paper proposes a position-aided beam alignment method for millimeter wave backhaul systems with large phased arrays, reducing alignment time by using position information in fixed-node scenarios.

## Contribution

It introduces an efficient beam alignment technique leveraging position data for fixed mmWave backhaul nodes with analog beamforming, addressing small displacements due to environmental factors.

## Key findings

- Reduces beam alignment time significantly.
- Provides insights on outage probability impacts.
- Enhances reliability of mmWave backhaul links.

## Abstract

Wireless backhaul communication has been recently realized with large antennas operating in the millimeter wave (mmWave) frequency band and implementing highly directional beamforming. In this paper, we focus on the alignment problem of narrow beams between fixed position network nodes in mmWave backhaul systems that are subject to small displacements due to wind flow or ground vibration. We consider nodes equipped with antenna arrays that are capable of performing only analog processing and communicate through wireless channels including a line-of-sight component. Aiming at minimizing the time needed to achieve beam alignment, we present an efficient method that capitalizes on the exchange of position information between the nodes to design their beamforming and combining vectors. Some numerical results on the outage probability with the proposed beam alignment method offer useful preliminary insights on the impact of some system and operation parameters.