Engineers Create Wi-Fi Using Less Power

Pretty clever. I wonder what the maximum range would be from the active device.

So far I have not found that WiFI was ever a major power waster in cell phones when compared to all the background app and unneeded crap they have running.

At my last job our company phones were good for maybe 5 - 8 hours between charges in factory default mode. After a lengthy dig and clean job to shut down and remove every useless background app or other unneeded function most of us got ours to run 12 - 15 hours between charges.

That was better but still pretty crappy compared to my personal Sonim Comando military spec phone that could run in normal mode for close to a week between charges and near a month in low power mode!

I know I have to turn off a lot of apps that uses it (with notices and such), otherwise my ipad battery drains within a few short hours

O they better be. Li-fi is coming so soon.

It may be clever but it is incredibly badly explained. As far as I can make out, a central transmitter radiates a WiFi frequency to the sensors, which individually modulate the signal and reflect the individually modulated versions of the signal to a receiving device, not necessarily in the same location as the original transmitter. Unless the original transmission is of huge power, these reflecting aerials/antennae have to be directional and the receiving stations in a static position. The individual sensors then have no knowledge of each other, so the signals could easily contend with each other. How does it really work?

It seems a lot like having a power meter at the radio station to determine how many people are listening.

Here is a little more detail on their passive wifi:

http://passivewifi.cs.washington.edu/files/passive_wifi.pdf