New DARPA challenge takes aim at spectrum sharing

The Defense Department has decided to make a game out of the problem of spectrum crowding.  The Spectrum Collaboration Challenge (SC2), the Defense Advanced Projects Research Agency’s newest Grand Challenge, will reward teams that develop systems  that collaboratively (as opposed to competitively) adapt in real time to changes in congested electromagnetic spectrum, DARPA said in a release.    

SC2’s primary goal is to imbue radios with advanced machine-learning capabilities to collectively develop strategies for optimizing use of the wireless spectrum that aren’t possible today due to the intrinsically inefficient approach of pre-allocating exclusive access to designated frequencies. 

Making more efficient use of the finite spectrum environment has become a DOD priority as the spectrum becomes ever more crowded, and DOD has to comply with a presidential order to free up 500 MHz of its spectrum for commercial use by 2020.

“I think today we’re in a good spot…We did well with the last auction and the money is there to change where DOD can move and share spectrum,” DOD CIO Terry Halvorsen said on March 22. However, “what I worry about right now,” Halvorsen said in testimony regarding his agency’s 2017 IT budget request, “is that the private demand for spectrum is going to exceed our ability to keep pace. We could, if we’re not careful, put some national systems at risk.”

DARPA is echoing similar alarms of Halvorsen. “Military operations increasingly rely on access to the wireless spectrum in order to assess the tactical environment and coordinate and execute their critical missions,” the agency said. “But the military is not alone in this challenge: as society enters an era in which ever more products, from refrigerators to automobiles to commercial unmanned aerial vehicles, need access to the spectrum, it will take far more efficient and nimble use of finite spectrum resources to meet the demand.” 

DARPA, on the other hand, seeks to take advantage of the advancements in artificial intelligence and machine learning, cornerstones of the Pentagon’s Third Offset Challenge, to spur new developments with an eye towards applications elsewhere in which collaborative decision-making is critical.

“DARPA Challenges have traditionally rewarded teams that dominate their competitors, but when it comes to making the most of the electromagnetic spectrum, the team that shares most intelligently is going to win,” said SC2 program manager Paul Tilghman of DARPA’s Microsystems Technology Office. “We want to radically accelerate the development of machine-learning technologies and strategies that will allow on-the-fly sharing of spectrum at machine timescales.”

“Some of this takes time and in this business I get that time is really valuable and it is money, but there is a physical limitation to how fast we can move the DOD systems either into the ability to share spectrum or out of some spectrum,” Halvorsen said. “And I worry maybe because we’re victims of our own success – we’ve done very well and the legislation that’s been written and the sharing has all worked to date – but what I hear from industry right now is, ‘Well, we want to go faster.’ And I don’t know that we can go much faster today on how we look at spectrum, make the decisions of whether we can get out and how we would share.” Halvorsen also noted that he thinks there should be a discussion surrounding how industry is evaluated in contributing to the spectrum sharing problem. 

DARPA is constructing the largest-of-its-kind wireless testbed for the challenge, called the Colosseum – for the Roman amphitheater – to serve during and after SC2 as a national asset for spectrum-sharing strategy, tactics and algorithm evaluation enabling researchers to conduct remote experiments in realistic user-defined radio-frequency environments. 

With a broad agency announcement to be released in the coming months, the challenge will unfold in three yearlong phases starting in 2017 finishing in 2020. Two million dollars are up for grabs for the team that develops radios that collaborate most effectively with various types of other radios to dynamically optimize spectrum use.

SC2 will host a website that will be updated with information regarding the challenge.