# Grip-Aware Analog mmWave Beam Codebook Adaptation for 5G Mobile Handsets

## TL;DR

This paper investigates how user hand grip affects beamforming codebook design for 5G mmWave handsets, proposing grip-aware and semi-aware adaptation schemes that significantly improve coverage and performance.

## Contribution

It introduces novel grip-aware and semi-aware codebook adaptation schemes that account for hand blockage effects in 5G mmWave handsets, enhancing beamforming performance.

## Key findings

- Grip blockage causes 20-25 dB antenna gain loss.
- Grip-aware scheme achieves over 50% better spherical coverage.
- Semi-aware scheme approaches the performance of the grip-aware scheme.

## Abstract

This paper studies the effect of the user hand grip on the design of beamforming codebooks for 5G millimeter-wave (mmWave) mobile handsets. The high-frequency structure simulator (HFSS) is used to characterize the radiation fields for fourteen possible handgrip profiles based on experiments we conducted. The loss from hand blockage on the antenna gains can be up to 20-25 dB, which implies that the possible hand grip profiles need to be taken into account while designing beam codebooks. Specifically, we consider three different codebook adaption schemes: a grip-aware scheme, where perfect knowledge of the hand grip is available; a semi-aware scheme, where just the application (voice call, messaging, etc.) and the orientation of the mobile handset is known; and a grip-agnostic scheme, where the codebook ignores hand blockage. Our results show that the ideal grip-aware scheme can provide more than 50% gain in terms of the spherical coverage over the agnostic scheme, depending on the grip and orientation. Encouragingly, the more practical semi-aware scheme we propose provides performance approaching the fully grip-aware scheme. Overall, we demonstrate that 5G mmWave handsets are different from pre-5G handsets: the user grip needs to be explicitly factored into the codebook design.