World’s Most Powerful Emulator of Radio-Signal Traffic Operational

DARPA's Colosseum, a next-generation electronic emulator of the invisible electromagnetic world, was opened for business. Though it resides in a mere 30-foot by 20-foot server room on the campus of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, MD, the Colosseum is capable of creating a much larger, and critically important wireless world. If all goes as planned during the Agency's three-year Spectrum Collaboration Challenge (SC2), competitors vying for $3.75 million in prize money will use the Colosseum-which today became fully accessible to them for the first time-as a world-unique testbed to create radically new paradigms for using and managing access to the electromagnetic spectrum in both military and civilian domains.

"The Colosseum is the wireless research environment that we hope will catalyze the advent of autonomous, intelligent, and-most importantly, collaborative-radio technology, which will be essential as the population of devices linking wirelessly to each other and to the internet continues to grow exponentially," said SC2 program manager Paul Tilghman. Traditional wireless communications systems are defined by a specification-a document that is the product of years of study and debate, and prescribes precisely how a radio system will work and how, if at all, it will get along with other radios. "We are asking SC2 competitors to devise fundamentally new radio systems that can learn from each other in real-time, making the need for arduous radio specifications obsolete," Tilghman said.

The Colosseum testbed is a 256-by-256-channel RF channel emulator, which means it can calculate and simulate in real-time more than 65,000 channel interactions among 256 wireless devices. Each simulated channel behaves as though it has a bandwidth (information content) of 100 MHz, which means the testbed supports 25.6 GHz of bandwidth in any instant. Moreover, each channel's transmission and reception frequency is tunable between 10 MHz (as in broadcast FM radio) and 6 GHz (as in WiFi). The amount of digital RF data coursing through the Colosseum each second, more than 52 terabytes, exceeds the estimated amount of information contained in the entire print collection of the Library of Congress. In short, said Tilghman, "the Colosseum is a magnificent electronic arena and just what we and the SC2 teams need for testing innovative, collaborative, intelligent radios against one another and, ultimately, to discover how to eke more capacity from the frustratingly finite spectrum."