Researchers at the University of Michigan have figured out a way to drastically increase your cellphone’s battery life, at least while using WiFi. By using what they’re calling E-MiLi, or Energy-Minimizing Idle Listening, professor Kang Shin (right) and student Xinyu Zhang have developed a proof of concept that could extend battery life up to 54-percent with the WiFi radio on. Even when idle, a wireless radio is actively checking for incoming traffic. E-MiLi scales back the wireless card’s clock to just 1/16th of its normal operating speed, and only kicks back into full gear when it senses incoming data.
Even when smartphones are in power-saving modes and not actively sending or receiving messages, they are still on alert for incoming information and they’re searching for a clear communication channel. The researchers have found that this kind of energy-taxing “idle listening” is occurring during a large portion of the time phones spend in power-saving mode—as much as 80 percent on busy networks. Their new approach could make smartphones perform this idle listening more efficiently. It’s called E-MiLi, which stands for Energy-Minimizing Idle Listening.
They discovered that, depending on the amount of traffic in the network, devices in power-saving modes spend 60 to 80 percent of their time in idle listening. In previous work, they demonstrated that phones in idle listening mode expend roughly the same amount of power as they do when they’re fully awake.