Dead Zones: They Can Run, but They Can't Hide

Like most people who use them, I like wireless networks--a lot. Which makes it that much more irritating when I stumble into a dead zone in the middle of a conversation or download. Moreover, I'm as baffled as the next person as to why one side of my living room can't pick up a signal, yet 10-feet away it's strong and clear.

Of course, this all could be avoided if wireless providers would identify--and compensate for--dead zones before building networks. However, this isn't cheap or easy, which is why WiFi providers build networks first, then plug holes later.

Apparently I'm not alone in my frustration, and I'm glad that Edward Knightly, a professor in electrical and computer engineering at Rice University, is frustrated by dead zones, too. But unlike me, Ed is smart enough to do something about it, as described in the paper Assessment of Urban-Scale Wireless Networks with a Small Number of Measurements that he co-authored with HP Labs research scientist Ram Swaminathan and Rice grad student Joshua Robinson.

The technique they came up with to tackle dead zones uses a small number of measurements to predict how well a wireless transmitter will cover a particular portion of a neighborhood. The only information required is basic topography, street locations, and general information about land use. The measurement framework that they present accurately characterizes the metric regions of a mesh note using a small number of measurements. Their primary focus is on coverage (signal strength).

As proof-of-concept, the team tested the technique both on Google WiFi, the free wireless Internet service Google provides in Mountain View, Calif., and TFA-Wireless, an experimental network in Houston, Texas, designed and built by Rice and owned and operated by the nonprofit Technology For All. TFA-Wireless provides high-speed Internet access to more than 4000 users in Houston.

"In the real world there are many things that can interfere with signals and limit coverage," says Knightly. "Our goal was to efficiently characterize the performance of urban-scale deployments, and our techniques can be used to either guide network deployment or to assess whether a deployed network meets its performance requirements."

And in the real world, this is a step to solving a real problem.

-- Jonathan Erickson
jerickson@ddj.com

Posted by Jon Erickson at 11:36 AM  Permalink