Battery-free BLE sensors securely identify with polarized backscatter signals
Secure Polarization-Shift Backscatter Identification Applied to Battery-Free BLE Sensors Powered by Wireless Power Transfer
Networking and Internet Architecture
Summary
Battery-free Bluetooth sensors that get their power wirelessly face challenges in secure identification. The authors present a method that uses a change in the polarization of the wireless power signal to send encrypted IDs without needing batteries or changing the main power harvesting parts. This method lets the sensors securely identify themselves before sending any data and works smoothly alongside normal Bluetooth communications. Tests show it can reliably send secure IDs while also improving how well the sensor harvests power.
What this means in practice
- •For wireless sensor integrators: Integrate secure identification into battery-free BLE sensors powered by wireless charging to verify devices before data communication.
- •For industrial iot engineers: Deploy battery-free sensors with improved power efficiency and secure ID for asset tracking and monitoring in harsh environments.
Authors
Taki Eddine Djidjekh, Quentin Bernyer, Alexandru Takacs
Abstract
This paper presents a lightweight and protocolindependent security mechanism for battery-free Bluetooth Low Energy (BLE) sensor nodes operating in Simultaneous Wireless Information and Power Transfer (SWIPT) architecture. The proposed approach exploits polarization-shift backscattering of the wireless power wave to transmit an encrypted device identification prior to data communication. A fail-safe RF switch and orthogonally polarized antennas are integrated as an external add-on module, enabling controlled backscatter without modifying the original energy-harvesting rectifier. The identification payload is encrypted using AES-128 and transmitted with minimal energy overhead. Experimental validation on a battery-free BLE sensor node demonstrates reliable extraction of the backscattered identification signal, seamless coexistence with BLE advertising, and improved RF-to-DC harvesting efficiency compared to rectifier-based backscatter solutions. The results confirm that polarization-shift backscatter identification provides an effective and practical security for battery-free BLE sensing systems.