New Wi-Fi system uses 10,000 times less power

Scientists, including those of Indian-origin, have demonstrated that it is possible to generate Wi-Fi transmissions using 10,000 times less power than conventional methods, an advance that may help save battery life in smartphones and other devices.
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.
"We wanted to see if we could achieve Wi-Fi transmissions using almost no power at all," said Shyam Gollakota, assistant professor at the University of Washington.
"That is basically what Passive Wi-Fi delivers. We can get Wi-Fi for 10,000 times less power than the best thing that is out there," said Gollakota.

Passive Wi-Fi can for the first time transmit Wi-Fi signals at up to 11 megabits per second that can be decoded on any of the billions of devices with Wi-Fi connectivity, researchers said.
These speeds are lower than the maximum Wi-Fi speeds but 11 times higher than Bluetooth, they said.

Aside from saving battery life on today's devices, wireless communication that uses almost no power will help enable an "Internet of Things" reality where household devices and wearable sensors can communicate using Wi-Fi without worrying about power.
To achieve such low-power Wi-Fi transmissions, the team essentially decoupled the digital and analog operations involved in radio transmissions.

The Passive Wi-Fi architecture assigns the analog, power-intensive functions - like producing a signal at a specific frequency - to a single device in the network that is plugged into the wall.
An array of sensors produces Wi-Fi packets of information using very little power by simply reflecting and absorbing that signal using a digital switch.
In real-world conditions, the team found the passive Wi-Fi sensors and a smartphone can communicate even at distances of 100 feet between them.
"All the networking, heavy-lifting and power-consuming pieces are done by the one plugged-in device," said Vamsi Talla, an electrical engineering doctoral student at UW.

"The passive devices are only reflecting to generate the Wi-Fi packets, which is a really energy-efficient way to communicate," said Talla.
Because the sensors are creating actual Wi-Fi packets, they can communicate with any Wi-Fi enabled device right out of the box.