Passive Cloud: The Greener Future of Wi-Fi
Today countless teams of Electrical Engineers are posed with the solving the same, yet until now seemingly unsolvable problem: how to innovate WiFi technology so as to avoid battery drain. This problem seems to only be exponentiating given that more and more devices not only have access to the cloud but it is increasingly the case that they exclusively access the cloud and have little to no device derived storage capabilities. When this is coupled with the ever present search for a good signal and improving upon and already present yet weak one, the problem is realized and it’s a doozie.
However, one tam out of the University of Washington might be on the cusp of get us in started in the right direction. They are doing so by introducing an entirely new approach to the hardware design that they claim will require 10,000 times less energy than conventional Wi-Fi. This is no doubt a lofty claim but in their initial trials they are beginning to back it up. They have coined the term “passive Wi-Fi” and works within the confines of traditional Wi-Fi infrastructure e.g. home router, it just does so much more efficiently. putting this into perspective, the most advanced low power Wi-Fi transmissions today use about 100s of milliwatters of energy, whereas what the Washington students are consuming no more than 10-50 microwatts- i.e. a savings of about 10,000 times.
The way this is achieved can be understood by looking at the way Wi-Fi traditionally operates. Wi-Fi as a general rule of thumb requires 2 radios to relay communications between one another. This requires a lot of energy because there is likely several devices using the same frequency that fall within the range of (2.4 GHz or 5 GHz). And each device must have a RF that enables a radio signal and a base band chip to encode the frequency with the meat of the operation, the data.
However, with passive Wi-Fi the device is enabled to separate, dormant sensors. Thus instead of each device using a radio frequency to receive the transmission of the signal, passive Wi-Fi only requires that 1 radio frequency be active.
Many people might look at this and ask “isn’t this just a mesh network ?” wherein signals bounce from one antenna to another, but it difference in a very important way. and is described in this way
“The low power passive device isn’t transmitting anything at all. It’s creating Wi-Fi packets just by reflection,” says Vamsi Talla, another student working on the project. “It’s a transmission technique that’s ultra low-powered, as opposed to a network device.”
Therefore, the “refection” is only happening as a process called “back scatter”
“For many Internet of Things applications, however, this technology is perfect. Radios typically account for the largest power draw of any cell phone.”
although there are clear issues to address in terms of our energy future and Wi-Fi in general it is clear that these researcheers are off to the right start. This team is off to a very right start by addressing the hardware not the energy production in general.