A Link Loss Model for the On-body Propagation Channel for Binaural Hearing Aids

TL;DR

This paper develops a deterministic model for ear-to-ear wireless link loss in binaural hearing aids, considering the effects of the pinna and propagation paths, validated through simulations and measurements on phantoms.

Contribution

The paper introduces a new deterministic model for ear-to-ear link loss that accounts for the pinna and dominant propagation paths, validated with simulations and physical measurements.

Findings

Model agrees with simulation results.

Pinna significantly affects link loss.

Heterogeneous phantoms show higher loss than homogeneous ones.

Abstract

Binaural hearing aids communicate with each other through a wireless link for synchronization. A propagation model is needed to estimate the ear-to-ear link loss for such binaural hearing aids. The link loss is a critical parameter in a link budget to decide the sensitivity of the transceiver. In this paper, we have presented a model for the deterministic component of the ear-to-ear link loss. The model takes into account the dominant paths having most of the power of the creeping wave from the transceiver in one ear to the transceiver in other ear and the effect of the protruding part of the outer ear called pinna. Simulations are done to validate the model using in-the-ear (ITE) placement of antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and body size. The model agrees with the simulations. The ear-to-ear link loss between the antennas for the binaural hearing aids in the homogeneous SAM phantom is compared with a heterogeneous phantom. It is found that the absence of the pinna and the lossless shell in the SAM phantom underestimate the link loss. This is verified by the measurements on a phantom where we have included the pinnas fabricated by 3D-printing.