QNRF Newsletter Archive

Managing invisible real estate

Wael Halwabi, TAMUQ class of 2011 and admitted to Caltech, demonstrates how to use portable spectrum analyzing devices.
A Qatar-based research team is working to predict where and when wireless frequencies are vacant so that the spectrum can handle up-and-coming technologies.

Wide, open air. You wouldn’t think it would be expensive, but it’s one of the most valuable natural resources a nation has. In fact, there’s a lot of real estate in the air that we use constantly but rarely think about.

Cell phones, smart phones, Wi-Fi networks, flight control towers, digital tablets, baby monitors, these devices and many more depend on electro-magnetic waves of information traveling through the air at different frequencies. The organization and designation of these devices’ signals occurs along the wireless frequency spectrum, a massive invisible grid.

This spectrum is well-mapped and limited by frequency bands running through the air. Yet, like a highway system that was built before cities, it has become overly crowded in some places and vacant in others. This is because it was first divided up back in the late 70s, when most of the gadgets we depend on today didn’t exist.

“So when the signals get crowded the system slows down; it’s the same thing as a traffic jam,” said Ali Gorcin, a PhD student from the University of South Florida (USF), working in conjunction with a team at TAMUQ on an ambitious wireless frequency spectrum project funded by Qatar National Research Fund’s National Priorities Research Program.

“Texting is like riding bicycles, talking on the phone is like driving cars, sending videos and rich media is like driving big trucks in terms of bandwidth consumed from the spectrum,” he continued. “Today, everyone is trying to pull big trucks into the spectrum.”

Specific “lanes” are designated for specific “trucks,” but some are used a lot less than others, especially those designated for older technologies, Gorcin said. Meanwhile, some areas of the spectrum become jam-packed, and the air space for new and developing technologies is thinning.

To address this problem, the Qatar-based researcher team, headed by Dr. Khalid Qaraqe, Professor of Engineering at TAMUQ, involving researchers from TAMUQ and USF, is working to predict where and when on the spectrum free space exists so as to help promote its efficient use. It’s a study that’s on track to be among the most comprehensive and pioneering of its kind.

Their most recent results—based on a model involving four remote signal devices positioned around Doha and their collected data, crunched by a super computer at TAMUQ—show that they can predict with more than 90 percent accuracy when and where a certain part of the spectrum will be occupied.

The importance of predicting occupancy comes into clearer view when you consider that a lot of air space becomes vacant when not in use. Instead of one user per cell-phone frequency, there could be a primary and secondary user.
Wireless spectrum in US

A “map” of the wireless grid in the US shows crowded and wide-open areas. [Click to expand].
“Primary and secondary usage falls into a field we call cognitive intelligence radio,” said Dr. Qaraqe. “For example, if you have a vacation home, and you are not using it except during the summer, then you can rent your home to somebody else. But you are the primary owner for that home; when you want to use it, they need to leave.”

Like a summer home left vacant, unused frequency space is a waste of money, Dr. Qaraqe added. “Germany’s spectrum, for instance, is worth billions of dollars, and when you maximise this space, you earn more money.”

Devices that can jump from used to open frequencies do not exist yet but are under development in tandem with studies, like the TAMUQ-USF research team’s, to predict the activity of the spectrum.

“We’ve received major support from QNRF and Qtel, to participate in the hottest research worldwide,” said Dr. Qaraqe. “We’re able to make a global contribution while we build human capital here in Doha.”

Dr. Qaraqe has trained 24 undergrad students to work in his wireless laboratory, 50 percent of whom are Qatari. Because of QNRF’s and Qtel’s support, he said, he has retained solid researchers from the US as well.

NPRP: 08-152-2-043
Signal Intelligence for Next Generation Wireless Communications Systems
LPI Name: Dr. Khalid Qaraqe, Texas A&M University - Qatar

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