'Beamsteering' slashes mobile power consumption by 50%

Rice University engineer Hang Yu says "beamsteering" wireless broadcasts by mobile devices could help them save power and connect smarter.
Written by Andrew Nusca, Contributor on

The concept is simple enough: to preserve the battery life of your mobile phone, why not narrowcast, instead of broadcast?

As mobile electronics become more popular, from laptops to tablet computers, the issue of power consumption looms large -- specifically, how these devices connect to the cloud.

The problem: your device is broadcasting, sending its signal in all directions. But what if it could send a signal only to where it needs to?

Rice University researcher Hang Yu says broadcasting only in the direction of the next node is the answer -- and it's possible without increasing the size of the device, too.

Historically, radio signals have been steered with the use of several antennas. By forcing the signals to interfere with one another, they combine, forming a narrow beam that can be "steered" with signal changes.

But mobile devices don't have the room for multiple antennas -- nor the battery reserves to power them all. (After all, transmitted power may be lower, but the overall draw may not be.)

However, Yu says that antenna technology has advanced to the point where several antennas can be easily included in a netbook, Apple iPad or Amazon Kindle -- and that net power consumption is indeed lower.

There's one catch, however -- beamsteering can easily crowd out others on a shared network. So if you're in a coffeeshop and working on your presentation with a four-antenna laptop, you may be drowning out the barista who's trying to check her e-mail on her Samsung Galaxy Tab.

Yu says this issue can be addressed with a software solution, which he and other engineers developed. It's called "BeamAdapt," and it helps wireless devices negotiate with others to find optimal transmission for everyone.

For now, Yu has tested the software on small, real-world network and on a larger, simulated one. The results are promising: "BeamAdapt can reduce client power consumption by 40 percent and 55 percent with two and four antennas, respectively, while maintaining the same network throughput," he said to Technology Review.

(Interested in the specifics? Here's more information.)

But not unlike the U.S. nuclear treaty with Russia, the system only works when everyone agrees to use the software. Otherwise, someone gets to hog the airwaves, ruining it for everyone in the area.

The next step: build the technology out as a communication standard.

This post was originally published on Smartplanet.com

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