The Internet of Things (IoT) devices are found everywhere, from our homes to cities and even large industries like agriculture. But using IoT devices on such a large scale requires additional equipment, more space, and hardware, increasing its cost and power consumption. Recent developments in backscatter technology have helped reduce the costs and power, but it still lacks reliable downlink communication to fully enable an end-to-end IoT system. To bridge the gap, researchers from the University of Washington have come up with a new solution.
The Glaze system is a general paradigm for downlink communication that can be used with existing wireless signals to enable downlink data for IoT endpoints. The system opens a new channel of communication for ambient backscatter devices by overlaying data on existing signals, like WiFi or TV broadcast signals. Meant to be a low cost, low power solution for downlink communication, it features two components: a module and a receiver.
The module overlays data by reducing electric signals that travel to the wireless signals. It’s comprised of a signal detector, parameter optimizer, traffic predictor, and a Glaze embedder. Once connected to the antenna port of a wireless transmitter, it overlays the data on top of the wireless signals resulting in a composite signal that can be transmitted and received by legacy receivers and Glaze receivers.
Traditional receivers usually need lots of power to decode signals, but Glaze’s receiver is low powered, yet can still receive and decode Glaze signal transmissions. To break down the block diagram of the system, it is equipped with impedance matching, an envelope detector, a threshold compute and comparator, and a microprocessing unit. To decode signals, the components overlay data on the baseband of the wireless signal in the time domain allowing the receiver to decode without the power-consuming hardware.
Researchers tested the system by connecting the Glaze module to an FM transmitter broadcasting at 108mHz with its audio input coming from a PC. The Glaze module overlays data on top of the outputted RF signals. An FM antenna then receives the broadcast at 108Mhz.
In the future, they hope Glaze will be able to send low power wake signals to devices. They also hope it enables downlink data streaming to devices that work with smart city apps to control things like billboards, cameras, and bus schedules.