The new Passive Wi-Fi system also consumes 1,000 times less power than existing energy-efficient wireless communication platforms, such as Bluetooth Low Energy and Zigbee. A paper describing those results will be presented in March at the 13th USENIX Symposium on Networked Systems Design and Implementation.

"We wanted to see if we could achieve Wi-Fi transmissions using almost no power at all," said co-author Shyam Gollakota, a UW assistant professor of computer science and engineering. "That's basically what Passive Wi-Fi delivers. We can get Wi-Fi for 10,000 times less power than the best thing that's out there."

Prototype hardware has been buit and implements all four 802.11b bit rates on an FPGA platform. Their experimental evaluation shows that passive Wi-Fi transmissions can be decoded on off-the-shelf smartphones and Wi-Fi chipsets over distances of 30 - 100 feet in various line-of-sight and through-the-wall scenarios. Finally, we design a Passive Wi-Fi IC that shows that 1 and 11~Mbps transmissions consume 14.5 and 59.2 µW respectively. This translates to 10000x lower power than existing Wi-Fi chipsets and 1000x lower power than Bluetooth LE and ZigBee.