A new radio technology that enables smartphones and smartwatches to borrow energy from other larger devices when transmitting data could solve the 'constantly flat' smartphone battery problem.
The technology, developed by American researchers, is basically an enhanced Bluetooth, which enables the gadget to operate similarly to a radio-frequency identification (RFID) tag. That means that when data is being transmitted between two devices equipped with the technology, dubbed Braidio, it is the device with the larger battery and more power that ‘pays’ for the data transmission.
"We take for granted the ability to offload storage and computation from our relatively limited personal computers to the resource-rich cloud," explained Professor Deepak Ganesan from the University of Massachusetts Amherst, who led the research team.
"In the same vein, it makes sense that devices should also be able to offload how much power they consume for communication to devices that have more energy."
The Bradio, for braid of radios, can distinguish when the smaller device has enough power and can power itself from when it is running out of juice and needs some help.
In tests, the Bradio was able to extend the battery life of the smaller device hundreds of times. The energy-offloading technology, the team believes, could enable manufacturers in future to build smaller and lighter devices as they wouldn’t need to expand the batteries to provide more power.
Compared to using regular Bluetooth, the smaller device can extend its battery life up to 400 times with Bradio.
"To be clear, our results only cover the cost of communication or transmitting data," said Pan Hu, Ganesan’s graduate student who worked on the project. "If a radio is transmitting from a camera that consumes hundreds of milliwatts while using its sensor, clearly the sensors may dominate total power consumption and reduce the benefits of optimising the radio."
Bradio itself, the researchers said, consumes about as much power as regular Bluetooth and is made of simple low-cost components. The system can operate in several modes and uses algorithms than enable monitoring the channel and energy at the transmitter and receiver to dynamically adjust the energy usage in order to optimise throughput.
The team hopes they could further redesign the device to a smaller size. They also want to increase its efficiency before aiming for the mass market.
"Wearable devices are often bulky due to large batteries needed for adequate battery life," said Ganesan. "Perhaps such energy offload techniques can reverse this trend and enable thinner and lighter devices."
The researchers presented the technology at a conference of the Association for Computing Machinery in Florianópolis, Brazil.