Passive Wi-Fi — which lets devices communicate using 10,000 times less power than traditional Wi-Fi — is poised to transform the Internet of Things (IoT), especially if the University of Washington team that created it is right about its potential. That change could be significant in higher education, likely to be an early IoT adopter as students bring more smart consumer devices onto campus.
“We all love Wi-Fi, but it still uses a lot of power,” says Shyam Gollakota, a University of Washington professor and one of the project’s four researchers. “Passive Wi-Fi provides you Wi-Fi for almost no power, so now you can have Wi-Fi in more everyday objects.”
The reason, in short: batteries. In the existing digital baseband/analog radio frequency system, power drains from devices connected to Wi-Fi. By removing the inefficient analog component with a “backscatter” system that employs reflections to create Wi-Fi packets, the researchers believe they can drastically increase battery life in objects ranging from smartphones to smart medical implants.
“In your home, if you have a lot of security systems that are battery powered, they can use our technology and their batteries will last 10 to 20 years, as opposed to six months or so,” says Vamsi Talla, who earned his Ph.D. while working on the project. “Any device that needs connectivity where power is a problem will benefit from passive Wi-Fi.”
The potential breakthrough has excited analysts like Ranveer Chandra, principal researcher for Microsoft. “The passive Wi-Fi system, as reported, consumes a few orders of magnitude less power than Bluetooth or Zigbee, while also enabling higher throughputs,” he says. “The key insight — to reduce the energy consumed by the analog radio frequency components and replace them with backscatter — is brilliant.”
The research team presented their findings at the USENIX Symposium on Networked Systems Design and Implementation in March. They have also started a company, Jeeva Wireless, to explore commercialization. “I can think of several applications where passive Wi-Fi could help,” Chandra says.
“For example, batteryless devices might be a real possibility if the researchers can achieve their targeted power numbers. One can imagine motion sensors that do not require a battery and can communicate over Wi-Fi with your phone or PC. Similarly, the doorbell camera might have a battery that practically never has to be replaced. These applications truly change the paradigm of the next generation of indoor Internet of Things applications.”