In-the-Wild Interference Characterization and Modelling for Electro-Quasistatic-HBC With Miniaturized Wearables

Area of Science:

• Biomedical Engineering
• Signal Processing
• Wearable Technology

Background:

• Human Body Communication (HBC) is emerging as a secure alternative to wireless body area networks (WBAN).
• Electromagnetic (EM) HBC above 10 MHz is susceptible to eavesdropping, while interferences affect WBAN in the 40-400 MHz range.
• Electro-quasistatic (EQS) mode of HBC offers covert data transmission below 10 MHz by containing signals within the body.

Purpose of the Study:

• To explain the interference coupling modality and sources in the sub-10 MHz EQS HBC region.
• To address the knowledge gap crucial for selecting appropriate data transmission bands.
• To propose a human biophysical interference pickup model.

Main Methods:

• Designed a wearable-sized measurement setup with a small ground plane to recreate real-world wearable interference scenarios.
• Explained interference coupling modality in the EQS region.
• Proposed a novel human biophysical interference pickup model.

Main Results:

• Interference coupling modality and sources in the EQS region were explained.
• A human biophysical interference pickup model was proposed for the first time.
• Interference measurement results using a wearable device were presented up to 250 kHz in various environmental settings.

Conclusions:

• Understanding EQS interference is critical for secure and reliable HBC systems.
• The proposed human biophysical interference pickup model advances the field of wearable interference analysis.
• This study provides essential insights for optimizing HBC data transmission bands and device design.