SleepWell system puts mobile devices to sleep to conserve power while waiting on Wi-Fi

Although the number of Wi-Fi hotspots has increased dramatically in most places over the past few years, the explosion in the number of smartphones and laptops attempting to make use of such connections means that getting decent download speeds is as difficult as it always was. Not only is this frustrating, it can also be a major drain on the batteries of mobile devices. In an effort to address one of these problems, a Duke University graduate student has developed software called SleepWell that allows mobile devices to take a nap to save power while they wait for their turn to download.

The SleepWell system was developed by Justin Manweiler, who likens its advantages to those that would be seen if companies in major cities staggered their work hours to reduce rush hour traffic. And like traffic congestion relief, the biggest advantages of the SleepWell system would be seen in cities where the density of Wi-Fi-enabled devices is greatest.

"The SleepWell-enabled Wi-Fi access points can stagger their activity cycles to minimally overlap with others, ultimately resulting in promising energy gains with negligible loss of performance," said Manweiler.

When a neighboring device is downloading information on the same Wi-Fi network, other devices can go to sleep while waiting for their turn to download, thereby saving precious battery life. Depending on usage patterns, Manweiler claims the system can potentially double the battery life of mobile devices.

Romit Roy Choudhury, assistant professor of electrical and computer engineering at Duke University's Pratt School of Engineering who oversaw Manweiler's work, says the emergence of cloud computing will see mobile devices needing to access the Internet more frequently and that such frequent access could be severely constrained by the energy toll that Wi-Fi takes on the device's battery life.

"Energy is certainly a key problem for the future of mobile devices, such as iPhones, iPads and Android smartphones," Roy Choudhury said. "The SleepWell system can certainly be an important upgrade to Wi-Fi technology, especially in the light of increasing Wi-Fi density."

Having tested the technology over a number of device types and situations, Manweiler is confident that the SleepWell system is, "a viable approach for the near future."