All in the signal's header
Boffins at the University of Michigan researchers have come up with a new power management system for smartphones that could improve battery life by 50 per cent.
Xinyu Zhang and Kang Shin have created a proof-of-concept system known as E-MiLi, or Energy-Minimizing Idle Listening. This fixes the energy waste that occurs when "sleeping" phones are looking for incoming messages and clear communication channels.
E-MiLi slows down the clock of a phone's WiFi card by up to 1/16 its normal frequency in order to save power, but then kicks it back up to full speed when information is coming in. The phone uses the header of the incoming message to wake itself up from its "subconscious mode," so the clock is at a full speed to receive the main message.
It does require firmware to be installed on phones and other devices that would be sending them. The header would need to be encoded in such a way that the receiving phone could detect it too. Shin and Zhang have created such firmware, but WiFi chipset manufacturers would have to adopt it, and then smartphone manufacturers would in turn have to start using those chips.