A team from the Georgia Tech Research Institute (GTRI) took second place in the Defense Advanced Research Projects Agency’s (DARPA) Spectrum Challenge. Bob Baxley, Andy Henshaw, Ethan Trewhitt, and Sean Nowlan prepared GTRI’s entry in and attended the competition at DARPA.
The Spectrum Challenge allowed teams to cooperatively share and competitively compete for established radio bandwidth, utilizing innovative and adaptive software techniques to sense and adapt to both congested and contested electromagnetic environments.
“The Spectrum Challenge consisted of two components—cooperative and competitive,” said GTRI researcher and team leader Bob Baxley. “The cooperative tournament happened in conjunction with three other teams, where each team had to get their packets across the link while allowing others to transmit.”
During the competitive component, Baxley said, teams worked to interfere with others’ transmissions, while trying to get the most packets across the link. “In this component, the goal was to jam your opponents efficiently,” he said.
GTRI took second place in the competitive component, winning $25,000. Together with Tennessee Technological University and an independent team, GTRI was one of three prize winners in the final competition, in which DARPA awarded $150,000 of prize money.
DARPA initiated the challenge more than a year ago, with 90 teams registering from around the world. The task at hand: Demonstrate a radio protocol and adaptive waveform that can best use an established communication channel with both other users and intentional interfering signals present.
Over the last year, various qualification events led 15 teams from the initial 90 registrants to qualify for the finals, which were held March 19 and 20, 2014. Teams submitted software images of their designs prior to the competition after remotely connecting to a radio testbed at Rutgers University to test their designs between the preliminary and final events, and then gathered at the DARPA Conference Center in Arlington, Va., for the final events.
Although GTRI team members were thrilled with performance in the competitive finals, they felt going in that the cooperative finals might best show off the performance of their design. “It’s funny, because we actually felt we were stronger in the cooperative component,” Baxley said. Three main objectives comprised this challenge, he said. “Get your files through, get your teammates’ files through and then get off the line. We were one of the only teams to get all our packets through in every match.”
In the accompanying video, the graphic representation shows the red area (GTRI’s information packets) and the blue area (teammates’ information packets, which conveniently forms the letters “GTRI” ) allow both teams’ information to use the signal at the same time.
Baxley is director of the Software Defined Radio Lab in GTRI’s Information and Communications Laboratory (ICL). His research focuses on cognitive radio and software-defined radio frequency technologies. Cognitive radio is an “intelligent” radio that can autonomously adjust to its environment. It can use the best wireless channels in its vicinity, changing its transmission and reception parameters to allow concurrent wireless communications in a given spectrum band at a single location. The challenges of cognitive radio are among the areas of focus in ICL’s Communications, Systems and Spectrum Division (CSSD), led by Division Chief Tanah Barchichat.
CSSD’s cutting-edge research work includes customizing and deploying small-scale, special-purpose adaptations of commercial cellular and satellite networks, developing software-defined radio applications to improve link performance and increase spectrum efficiency, implementing and integrating 4G LTE systems in a tactical environment and modeling communication environments to test other tactical systems.
A key component of these efforts is the management and operation of communications, electronic warfare and sensing systems simultaneously in the congested, contested spectrum. This topic is the subject of a GTRI-wide Strategic Initiative in Spectrum Operations led by Eric Barnhart, a GTRI Fellow in ICL.
“The Spectrum Challenge exceeded expectations for stimulating new technologies and attracting new talent,” said Dan Kaufman, director of DARPA’s Information Innovation Office, in a press release. “As competitors alternately battled over and worked to share the spectrum, it was easy to see how these advanced capabilities could prove invaluable in a wide range of military and civilian applications that seek to maximize the value of this precious and finite resource.”
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