Inter-Technology Backscatter: Towards Internet Connectivity for Implanted Devices (1607.04663v1)

Abstract: We introduce inter-technology backscatter, a novel approach that transforms wireless transmissions from one technology to another, on the air. Specifically, we show for the first time that Bluetooth transmissions can be used to create Wi-Fi and ZigBee-compatible signals using backscatter communication. Since Bluetooth, Wi-Fi and ZigBee radios are widely available, this approach enables a backscatter design that works using only commodity devices. We build prototype backscatter hardware using an FPGA and experiment with various Wi-Fi, Bluetooth and ZigBee devices. Our experiments show we can create 2-11 Mbps Wi-Fi standards-compliant signals by backscattering Bluetooth transmissions. To show the generality of our approach, we also demonstrate generation of standards-complaint ZigBee signals by backscattering Bluetooth transmissions. Finally, we build proof-of-concepts for previously infeasible applications including the first contact lens form-factor antenna prototype and an implantable neural recording interface that communicate directly with commodity devices such as smartphones and watches, thus enabling the vision of Internet connected implanted devices.

• The paper demonstrates a novel backscatter technique that converts Bluetooth signals into Wi-Fi, achieving 2-11 Mbps data rates for implanted devices.
• It employs a single-sideband design using Bluetooth's GFSK to generate standard-compliant Wi-Fi signals, enhancing spectral efficiency.
• Experimental results indicate low power use (around 28 µW) and a communication range up to 90 feet, underscoring its potential for biomedical applications.

Inter-Technology Backscatter: Towards Internet Connectivity for Implanted Devices

The paper introduces a pioneering approach termed inter-technology backscatter, which enables direct communication between implanted medical devices and commodity mobile devices using Bluetooth transmissions to generate Wi-Fi and ZigBee-compatible signals. This work is conducted by a team at the University of Washington, demonstrating a novel use of backscatter communication to bridge disparate wireless communication protocols effectively.

Technical Contributions and Methodology

The primary technical innovation detailed in the paper is the ability to leverage Bluetooth transmissions to create standard-compliant Wi-Fi and ZigBee signals through a backscatter mechanism. Key aspects of this methodology involve:

• Bluetooth to Wi-Fi Signal Conversion: By backscattering Bluetooth transmissions, the research achieves the synthesis of Wi-Fi signals with data rates ranging from 2 to 11 Mbps. This is a significant advancement given that prior backscatter methods have not typically aligned with established Wi-Fi packet standards nor reached these data rates.
• Single-Sideband Backscatter Design: This approach uniquely utilizes Bluetooth’s Gaussian Frequency Shift Keying (GFSK) to produce single-tone signals, enabling the creation of single-sideband modulated signals that avoid the common inefficiencies associated with redundant spectral use. This novel design enhances spectral efficiency by eliminating the unwanted mirror sideband that typically arises in double-sideband backscatter designs.

Numerical Results and Performance Evaluation

The research presents empirical evaluations of this system, showing that using this method can generate Wi-Fi signal transmission effectively. An extensive evaluation involving various device configurations reveals:

• The backscatter system achieves low power consumption metrics, specifically around 28 µW for generating 2 Mbps Wi-Fi signals, indicating substantial energy efficiency, which is crucial for the power-constrained nature of implanted devices.
• The demonstrated communication range extends up to 90 feet with appropriate configurations, providing compelling evidence of the viability for practical applications in personal area networks.

Implications and Future Prospects

The implications of this research are significant both theoretically and practically. By enabling direct communication between implanted devices and standard mobile technology infrastructures, it simplifies deployment and reduces hardware costs. This capability can transform medical monitoring and treatment possibilities, enhancing quality of life for users reliant on medical implants for chronic condition management.

Looking ahead, future developments could explore the integration of newer Bluetooth standards and data packet optimizations to further improve throughput and energy efficiency. Moreover, the extension of this technique to more sophisticated modulation schemes such as OFDM (Orthogonal Frequency-Division Multiplexing) could potentially increase the data rates of backscatter transmissions even further.

In conclusion, this paper presents a novel and efficient method for achieving Internet connectivity for implanted devices using commodity devices. Its results pave the way for broader adoption of biomedical implants in networked environments, suggesting a transformative potential in the landscape of wireless communication and medical technology integration.