New Backscatter Sensors Operate Over Long Ranges with Very Little Power

The Holy Grail of connected sensors and devices is to be able to transmit data over long distances without consuming much power. Now, a new breakthrough from researchers at the University of Washington seems to have achieved that, all at a very low cost. The team, led by Shyam Gollakota of Paul G. Allen School of Computer Science & Engineering, was able to accomplish this by creating a new type of backscatter signal.

Backscatter communication works by emitting a radio signal, and then monitoring the reflections of that signal from sensors. Because the radio signal is created by a transmitter, the sensors themselves require very little power. But noise in that signal has traditionally limited backscatter communications. The key to this breakthrough is a new type of signal modulation called chirp spread spectrum.

By using chirp spread spectrum modulation with their backscatter system, the team was able to transmit data up to 2.8 kilometers. The sensors themselves could run on mere microwatts, so they only require very small batteries and could potentially even run from harvested ambient energy. Even more promising is the cost — at bulk pricing the team believes individual sensors would cost just 10 to 20 cents per unit.

To commercialize the project, the team has started Jeeva Wireless, and they plan to begin selling early devices within 6 months. The potential applications are virtually endless, and could be used for everything from wearable health monitors, to agricultural sensors, to scientific data collection devices. While there are no firm initial products yet, the team has created prototypes in the form of flexible sensors worn on the skin, smart contact lenses, and more.