Author(s): Raghu Gopal
Researchers funded by the National Science Foundation, the University of Washington and Qualcomm have developed a Wi-Fi technology that reduces energy consumption by 10,000 times compared with current versions of Wi-Fi. Such a level of efficiency could see it replace current low-power connectivity methods such as ZigBee and Bluetooth Low Energy.
Their results will be presented at the USENIX Symposium on Networked Systems Design and Implementation in Santa Clara, in March. The technology, dubbed passive Wi-Fi, is engineered to consume close to no power while maintaining transfer speeds of up to 11 Mbps. Although this is slow compared with the best Wi-Fi transfer rates, it's still about 11 times faster and 1,000 times more power-efficient than Bluetooth.
Passive Wi-Fi achieves its efficiencies by separating the analogue and digital functions of radio transmissions. While digital transmission has become much more energy-efficient over the years, analogue remains an energy drain. The team at the University of Washington managed to separate the two functions and use the principle of backscattering, where signal waves are diffused from one source back in the direction they came from. The team generated transmissions at rates equivalent to the older 802.11b standard using this backscatter communication method.
The majority of smart home products currently use low-power connectivity specs such as Bluetooth Low Energy, Z-Wave and ZigBee. Passive Wi-Fi could find adoption in this type of product given the wide implementation of Wi-Fi in phones, tablets, laptops and home routers.
Passive Wi-Fi isn't expected to be rolled out any time soon, but the project is something to follow. The technology would enable Internet of things devices to operate on standard Wi-Fi networks. Passive Wi-Fi could be a transformative technology — if it moves out of the lab.