Double your phone's battery life

Your fifth game of Angry Birds will no longer kill your phone’s battery life, thanks to a new technology named SleepWell.

With so many applications and games flooding our phones and laptops, they are constantly dying—it’s often a miracle if they last throughout the day without being charged. SleepWell solves this problem by optimizing the energy spent on Wi-Fi, which is one of the primary sources of battery drainage.

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Created by Justin Manweiler, an electrical and computer engineering graduate student at Duke, SleepWell mediates traffic at the network level in order to decrease the amount of energy wasted by phones and laptops using Wi-Fi signals.

“We want to make Wi-Fi work in a more energy-efficient manner,” Manweiler said. “There is a kind of fundamental problem with the way power saving has been done in that, as it was conceived, it was sort of planned for a network that has one access point. Real networks aren’t like that—lots of phones and laptops are trying to use the network at once, and all these networks lead to a lot of traffic.”

SleepWell controls traffic in a similar way that drivers often choose to leave and come home late from work in order to miss rush hour, Manweiler said. Rescheduling to avoid the traffic reduces the energy cost at no significant expense for the driver.

“Given that Internet traffic can tolerate a reasonable amount of latency/flexibility, SleepWell [access points] adjust their activity cycles to minimally overlap with others,” Manweiler wrote in his paper. “Each client frees up time to sleep, ultimately resulting in promising energy gains with practically negligible loss in performance.”

When hundreds of students at Duke are cluttered in the library, many of them will be sharing the same wireless channel and thus interfering with each other’s connections. Even at home, neighbors often share the same channel, Manweiler said. When all of these people try to wirelessly connect to the Internet at once, everyone’s connections are often weaker and slower.

“The algorithm is trying to isolate traffic,” Manweiler said. “We’re trying to add a little bit of scheduling on traffic so that the different access points are not trying to use the networks at the same time.”