Feeds

Boffins boost battery life with underclocked Wi-Fi

Removing the idle listening energy tax

Top 5 reasons to deploy VMware with Tegile

Scientists from the University of Michigan have devised a power management system that can greatly improve the lifespan of radio devices such as smartphones and laptops.

Engineering professor Kang Shin and doctoral student Xinyu Zhang have developed a technique for saving the battery life of Wi-Fi devices by clocking down the Wi-Fi radio system to 1/16th of its normal idling power output.

Dubbed "Energy-Minimizing Idle Listening" (E-MiLi), the technology works with current Wi-Fi technology (when the correct software is installed), and it can extend the life of a battery by up to 54 per cent, according to the boffins.

“We have a proof-of-concept implementation of E-MiLi based on software radios,” Xinyu Zhang tells The Register in an email exchange. In testing, the technique can boost smartphone battery life by 54 per cent.

Even in idle mode, standard Wi-Fi systems use more than two-thirds of the power consumed when fully operational, because the radio needs to be able to accept new data by examining incoming messages. The researchers call this "idle listening". E-MiLi allows the radio to largely power down, but it can reactivate by investigating header information on new data rather than examining all the data as a lump.

Specific tags in the header are needed and to make it work in existing kit, firmware and device drivers must be updated for the Wi-Fi card embedded in those mobile devices. The Wi-Fi cards also need to support downclocking at the hardware level.

"We came up with a clever idea," Shin says. "Usually, messages come with a header, and we thought the phone could be enabled to detect this, as you can recognize that someone is calling your name even if you're 90 per cent asleep."

Shin and Zhang present their paper on September 21 at the ACM International Conference on Mobile Computing and Networking in Las Vegas. They are now working on other power-saving techniques for Wi-Fi, specifically looking at regulating voltage directly.

“We have not completed experiments with voltage scaling. We expect much higher gain, because the power consumption is proportional to clock rate, and proportional to the square of voltage,” Xinyu Zhang says. ®

Security for virtualized datacentres

More from The Register

next story
Brit telcos warn Scots that voting Yes could lead to HEFTY bills
BT and Co: Independence vote likely to mean 'increased costs'
Phones 4u slips into administration after EE cuts ties with Brit mobe retailer
More than 5,500 jobs could be axed if rescue mission fails
New 'Cosmos' browser surfs the net by TXT alone
No data plan? No WiFi? No worries ... except sluggish download speed
EE buys 58 Phones 4u stores for £2.5m after picking over carcass
Operator says it will safeguard 359 jobs, plans lick of paint
Radio hams can encrypt, in emergencies, says Ofcom
Consultation promises new spectrum and hints at relaxed licence conditions
Google+ GOING, GOING ... ? Newbie Gmailers no longer forced into mandatory ID slurp
Mountain View distances itself from lame 'network thingy'
Vodafone to buy 140 Phones 4u stores from stricken retailer
887 jobs 'preserved' in the process, says administrator PwC
Bonking with Apple has POUNDED mobe operators' wallets
... into submission. Weve squeals, ditches payment plans
Drag queens: Oh, don't be so bitchy, Facebook! Let us use our stage names
Handbags at dawn over free content ad network's ID policy
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.