University of Washington Engineers Created Passive Wi-Fi, Able To Transmit Wi-Fi Signal Using 10,000 Times Less Power Than Conventional Wi-Fi devices

Wi-Fi signal is almost everywhere around us, completely coating most urban areas. It became a sort of a street light for our generation; you can connect to one almost anywhere, allowing you to be washed by the bright light of bandwidth. The problem with Wi-Fi is the technology uses too much energy. Maintaining the connection drains batteries, making connected devices to relatively quickly run out of power.

Image Courtesy Of University of Washington

It can be problematic, especially for devices packing humble batteries, like smartphones. Now, a team consisting out of computer scientists and electrical engineers from the University of Washington made Passive Wi-Fi, able to transmit Wi-Fi signal using 10,000 times less power than a conventional Wi-Fi emitters use. Further, the Passive Wi-Fi uses 1,000 times less power than Bluetooth Low Energy, one of the most energy-efficient wireless communication system.

Shyam Gollakota, the co-author of the research and a UW assistant professor of computer science and engineering said that “We wanted to see if we could achieve Wi-Fi transmissions using almost no power at all. 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.”

Aside from using incredibly low amounts of power, Passive Wi-Fi isn’t so bad when we talk about the maximum Wi-Fi speeds. The technology can emit Wi-Fi signal at a bit rate of up to 11 Megabits per second, 11 times higher than Bluetooth. It is still very far from achieving speeds comparable to maximum speeds of regular Wi-Fi devices, but the best thing about the signal is that all devices equipped with a Wi-Fi receiver can decode the signal.

In order to achieve the incredible energy-efficiency, the team decoupled the digital and analog operations involved in Wi-Fi transmission, assigning the analog functions (analog functions spend large amounts of electricity) to a single device in a network that’s plugged into a wall.

Image Courtesy Of University of Washington

An array of sensors is used in order to produce wireless packets of information, in a way that reflects and absorbs a Wi-Fi signal by using a digital switch, with an extremely humble amount of power. The max distance between a Passive Wi-Fi and a receiving device is up to 100 feet. Co-author Vamsi Talla stated that “All the networking, heavy-lifting, and power-consuming pieces are done by the one plugged-in device. The passive devices are only reflecting to generate the Wi-Fi packets, which is a really energy-efficient way to communicate.”

Bruce Kellogg, another co-author explained that “Our sensors can talk to any router, smartphone, tablet or other electronic devices with a Wi-Fi chipset,” and that “The cool thing is that all these devices can decode the Wi-Fi packets we created using reflections so you don’t need specialized equipment.”

Basically, Passive Wi-Fi can immensely help IoT (Internet of Things) to become a mainstream technology because it can now use very little amounts if power while keeping all of our home devices connected. Smart homes can be interconnected via Wi-Fi. Wi-Fi hasn’t been used for that since it used too much power. But, Now that we can achieve Wi-Fi for tens of microwatts of power and can do much better than both Bluetooth and ZigBee, you could now imagine using Wi-Fi for everything,” said Joshua Smith, a co-author of the research.


Source: University of Washington

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