Pure Wi-Fi Uses 10,000 Times Less Power Than Regular Wi-Fi

Researchers at the University of Washington (UW) have developed a Wi-Fi system that drains 10,000 times less power than conventional WLAN, in a development that could extend the battery life of smartphones and make Wi-Fi more suitable for the Internet of Things (IoT).

Much of the mobile industry’s attempts to address battery life have focussed on components, fast charging and the batteries themselves, but efforts to improve the energy efficiency of networks have been less common.

A team of computer scientists and electrical engineers say their system, known as Pure Wi-Fi, achieves its power efficiencies by separating the analogue and digital functions of radio transmissions. While the latter are extremely power efficient, the former still use a lot of energy.

Pure Wi-Fi efficiency

Pure Wi-Fi assigns analogue functions, such as the production of a signal at a specific frequency, to a single device on a wall. An array of sensors then produce Wi-Fi packets of data by reflecting and absorbing that signal using a digital switch.

In real life tests, the researchers were able to communicate with the sensors using a smartphone at a range of 100 feet.

“All the networking, heavy-lifting and power-consuming pieces are done by the one plugged-in device,” said co-author Vamsi Talla, an electrical engineering doctoral student. “The passive devices are only reflecting to generate the Wi-Fi packets, which is a really energy-efficient way to communicate.”

There is a downside however. Pure Wi-Fi can only achieve speeds of 11Mbps, a fraction of the maximum speed afforded by conventional Wi-Fi. This might not be the best for video streaming and other data intensive activities, but could lend itself to IoT applications that don’t require huge transmissions.

Already compatible

Many smart home products uses proprietary systems like Zigbee or Bluetooth despite the availability of Wi-Fi for this exact reason. The mobile industry is also working to standardise Narrowband IoT (Nb-IoT) as a power efficient way of connecting the IoT using cellular infrastructure.

The researchers say the ubiquitous nature of Wi-Fi and the fact that so many devices are already compatible with the standard gives Pure Wi-Fi an advantage and could result in the development of new types of communication

“Our sensors can talk to any router, smartphone, tablet or other electronic device with a Wi-Fi chipset,” added co-author and electrical engineering doctoral student Bryce Kellogg. “The cool thing is that all these devices can decode the Wi-Fi packets we created using reflections so you don’t need specialized equipment.”

“Even though so many homes already have Wi-Fi, it hasn’t been the best choice for that,” commented co-author Joshua Smith, UW associate professor of computer science and engineering and of electrical engineering. “Now that we can achieve Wi-Fi for tens of microwatts of power and can do much better than both Bluetooth and ZigBee, you could now imagine using Wi-Fi for everything.”

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