Passive Wi-Fi could solve IoT power problems

Passive Wi-Fi could solve IoT power problems

Passive Wi-Fi could solve IoT power problems
Passive Wi-Fi could solve IoT power problems (Image: University of Washington)

Researchers from the University of Washington (UW) have created a new Passive Wi-Fi system that consumes 10,000 times less power than conventional Wi-Fi and 1,000 times less than existing energy efficient methods, such as Bluetooth Low Energy (LE). This could be good news for IoT.

The technology has also been named one the year’s 10 breakthrough technologies by MIT Technology Review and it could have a huge impact on the Internet of Things (IoT) industry.

Although the ubiquity of Wi-Fi is one of its strongest advantages, the power it consumes is an issue, particularly as more connected devices begin to enter the market. Passive Wi-Fi transmits signals at a bit rate that is lower than the maximum Wi-Fi speed but 11 times higher than Bluetooth, but all devices with Wi-Fi connectivity are capable of decoding signals sent by Passive Wi-Fi.

Reducing energy consumption for IoT

The researchers at UW were able to vastly reduce the power consumption of their Wi-Fi signals by decoupling the digital and analogue components of radio communications. The power-intensive analogue functions are assigned to a single device plugged into the wall, which produces the Wi-Fi signal. The passive sensors then simply reflect and absorb that signal using a digital switch, meaning energy consumption is kept to a minimum.

“All the networking, heavy-lifting and power-consuming pieces are done by the one plugged-in device,” explained Vamsi Talla, co-author of a paper detailing the technology. “The passive devices are only reflecting to generate the Wi-Fi packets, which is a really energy-efficient way to communicate.”

Passive Wi-Fi will face competition from other low energy communications, all seeking to dominate the Internet of Things market. Long Range Radio, or LoRa, is already being trialled in several world cities, while a number of businesses demonstrated their Bluetooth IoT offerings at Mobile World Congress last month.

However, Passive Wi-Fi does hold some advantages, namely that Wi-Fi is already present in so many homes, meaning that integration between IoT networks becomes less of a problem. The technology has also demonstrated impressive range, with researchers able to connect smartphones and passive sensors at distances of up to 100 feet.