ECE: Electrical & Computer Engineering
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Cognitive Radio Goes Jammin’

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According to the Cyberstates 2008 report by the AeA (formerly American Electronics Association), Virginia has the highest density of high-tech workers in the country. Initiatives across the state aim to build on this base and develop the technology that keeps Virginia firms competitive. ECE’s Tamal Bose is working on two projects with firms in central Virginia — jammers for IEDs and remote kill switches with geolocation technology. For more information on Wireless@VT, please visit For information on CAER, please visit

Tamal Bose and Jeff Reed (Photograph by Jim Stroup)

From jamming radio-triggered explosives to building the country’s first-of-its-kind cognitive radio testbed, Tamal Bose is applying signal processing technology to business demands of today and to the needs of tomorrow’s technology.

Bose’s team is working on jamming and kill-switch technology that will help build the technology and competitive base of Virginia firms. The projects are funded by the Center for Advanced Engineering and Research (CAER), an organization that teams university research with growth industries in central Virginia.

Cognitive jammers

Bose is working with Advanced Management Technology, Inc., (AMTI) to create smart, collaborative jammers that prevent detonation of radio-triggered IEDs (improvised explosive devices). The electronic triggers for IEDs are often radio signals, according to Bose. “By using cognitive radio techniques, we can design smart jammers that don’t wipe out the entire frequency band,” he said. “Instead, the jammer can look at the statistical properties of the signal and decide what to jam and what not to jam. They learn from their past experience in the radio environment.”

Jammers have been used with convoys in Iraq, he noted. “They have used jammers to create a bubble around the convoy, but communication within the convoy could be disrupted. With smart jammers, communication does not get disrupted and enemy communications can be jammed without them realizing it,” he said.

Wireless features for kill switches

Another business development project – with Blue Ridge Technologies – involves designing an architecture for incorporating wireless technology in a remote kill switch. Most electrical kill switches have a hard physical interface between the device and the controller or use low power, short-range, wireless technologies.

“This technology would use existing networks to remotely control equipment,” Bose said, adding that applications would be in commercial, residential, industrial, and military situations. “Leasing and rental firms would like to be able to deactivate equipment with past due payments, for example. Or large industrial complexes can shut down critical equipment from a central location during emergencies.” The kill switch would include geolocation technology so that the firms can locate their equipment and disable it when needed.

The challenge is including all the features, but keeping it extremely simple to use. “If it is too complex, it won’t be used; also it will be more expensive,” he said.

Cognitive radio network testbed

Bose is co-director of Wireless@Virginia Tech and is involved in building the teams and the technology for large research efforts in wireless communication. He serves as the lead investigator at Virginia Tech for the Wireless Internet Center for Advanced Technology (WICAT), headed by the Polytechnic Institute of New York University. WICAT is one of 40 I/UCRC multi-university research centers funded by the National Science Foundation (NSF).

Virginia Tech’s involvement with WICAT focuses on cognitive radio based wireless networks and building a cognitive radio network testbed.

Tamal Bose and Jeff Reed (Photograph by Jim Stroup)

Reed and Bose examine the features of nodes that will be installed in the ceiling of the new ICTAS building

The testbed will be the first of its kind in the country, employing 48 cognitive radio nodes in the ceiling of the new ICTAS (Institute for Critical Technology and Science) building on campus. Built with funding from ICTAS, the testbed is currently six nodes, but with a new $347,000 DURIP award from the Department of Defense, the system will be expanded this year. Jeff Reed is the principal investigator, and Bose is co-investigator.

The testbed will be used for experiments such as dynamic spectrum access, where secondary users share the same frequency as licensed users. “We’ll be able to do jamming projects, test interoperability of different radios, and test the effectiveness of algorithms for many different applications,” Bose said.

Wireless@Virginia Tech is also hoping to make the testbed a community resource, allowing groups across the country to log in and control the nodes remotely.