If you’ve ever trawled the Internet for advice on how to save battery life on your phone, you’ll know that the #1 tip is pretty much always the same: switch to Airplane Mode. Why? That Wi-Fi you’re using might be one of the best things that ever happened to us, but it uses a lot of power.
The good news is that computer scientists and engineers in the US have demonstrated that it’s possible to generate Wi-Fi transmissions using 10,000 times less power than conventional methods, and 1,000 times less than more energy-efficient alternatives such as Bluetooth. They’re calling it Passive Wi-Fi, and we need it in our lives now. “We wanted to see if we could achieve Wi-Fi transmissions using almost no power at all,” said Shyam Gollakota from University of Washington and a member of the team.
“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.”
Gollakota and his team figured out how to achieve low-power Wi-Fi transmissions by separating the digital and analogue operations involved in radio transmissions. Over the past couple of decades, big improvements have been made to the digital components used in these transmissions, and they’re now more efficient than ever. But no one’s really bothered with the analogue component, which means it still uses up a lot of power.
So instead of using up a lot of power to general signals on its own, Passive Wi-Fi is able to selectively reflect incoming radio waves and construct a new signal out of that, while at the same time absorbing energy from the signal it’s modifying to power its circuits.
Source: www.sciencealert.com
