In order to truly enable the vision of ubiquitous devices connected to the Internet (Internet-of Things or IoT), connections should be possible with a minimal overhead for deployment, device and operational costs. To limit the deployment overhead, wireless connectivity should occur via existing infrastructure. Unfortunately, the most popular wireless network in enterprises and healthcare facilities is Wi-Fi, and the power consumption of Wi-Fi chipsets is too large (100s of milliwatts) to be easily powered by small coin cell batteries without large operational costs to frequently replace or re-charge batteries. As a result, current deployments of IoT devices (like Google's Nest systems) are limited to locations where they can be plugged into a power source. This issue is currently holding back innovation in new IoT device concepts. Since reducing the power consumption of Wi-Fi transceivers using conventional techniques is not possible, a new communication approach is needed. The primary objective of this proposal is to enable new classes of battery-powered IoT devices that can directly communicate with Wi-Fi access points by just reflecting or backscattering existing Wi-Fi signals. Since backscattering requires only a passive antenna with a reflection circuit with computationally relaxed baseband specifications, low-power operation at the IoT device-level can be achieved. Successful research will enable more rapid adoption of IoT devices into existing infrastructure and will enable new classes of low-power environmental, industrial, smart home, and health monitoring applications. Beyond enabling exciting new applications, the project also proposes a synergistic educational and outreach plan that leverages technical work performed in the grant to build exciting new demos to be used in undergraduate and K-12 classroom settings. For example, a fruit-based energy harvesting system powering the developed low power tags which communicate directly with Wi-Fi devices will introduce students to the wonders of engineering in a pragmatic yet compelling way, with the hope of increasing diversity in science, technology, engineering, and mathematics (STEM)-related education environments.
The proposed work specifically aims to enable the first practical low-power, low-cost integrated circuit solution which can enable a network of backscatter tags to connect with existing and Wi-Fi protocols. It would be the first to include a low-power universal-WiFi wake-up receiver for efficient synchronization and medium access control for the backscatter tags, and then backscatter Wi-Fi compliant signals piggybacked with IoT data. Importantly, the proposed backscatter platform will operate seamlessly with all existing Wi-Fi infrastructure so as to not interfere with existing spectrally-efficient productive communication.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
