The utility of mobile devices lies in their ability
to access the Internet while keeping a synchronised track of relevant user data
such as contacts, status updates and more. However, the downside of this
always-on connectivity is the tendency for wireless connections to put undue
strain on mobile batteries, becoming one of biggest utilisers of device power.
WiFi is a known culprit in this case, especially because it is generally left
active over the course of the day. This is now poised to change. Researchers
from the University of Washington's Networks & Mobile Systems Lab led by
CSE professor Shyam Gollakota have proved it possible to create WiFi signals
that use only a tiny fraction of the power - one ten thousandth - compared to
the current standard. The technology is being called ‘Passive WiFi', and could
be a boon to extending the battery life of a range of mobile device like cell
phones, laptops as well as the multitude of IoT appliances and gadgets making
inroads into consumers' lives. The trick behind this technology's minuscule
power utilisation is in separating the analog and the digital parts of a
typical wireless circuit. The digital part of a WiFi component converts binary
information from a laptop or smartphone into a signalling standard that
conforms to WiFi transmission. The analog part modulates this digital
information into high-frequency waves that comprise the wireless signal - this
is the part that utilises the majority of the overall power drawn by a WiFi card.
In the new system, the researchers relocated this higher-power analog component
to a mains-connected device that sends out a wireless signal across a given
area. This signal is then absorbed or reflected by digital switches integrated
into devices, which serve to propagate the WiFi packets. The efficiency of this
approach rises as the number of devices around the transmitting unit increases.
Initial tests clocked data speeds of up to 11Mbps across a 100-foot range, and
was also shown to be backward compatible with existing wireless devices like
smartphones and tablets. All the while, the test devices functioned using
10,000 times lower power - levels that make it an order of magnitude more
efficient than even Bluetooth.
Source: DNA-14th-December-2016
