What is the Spectrum Collaboration Challenge?

Across the nation and around the world, the wireless revolution is fueling a voracious demand for access to the radio frequency (RF) spectrum. In the civilian sector, consumer devices from smartphones to wearable fitness recorders to smart kitchen appliances are competing for bandwidth. In the military there is a growing reliance on unmanned platforms, from underwater sensors to satellites, and a push for broadband connectivity for every member of every Service. Managing this increasing demand, while combating what appears to be a looming scarcity of RF spectrum is a serious problem for our nation.

Today’s approach, which is nearly a century old, isolates wireless systems by dividing the spectrum into rigid exclusively licensed bands, which are allocated over large, geographically defined regions. This approach rations access to the spectrum in exchange for the guarantee of interference-free communication. However, it is human-driven and not adaptive to the dynamics of supply and demand. At any given time, many allocated bands are unused by licensees while other bands are overwhelmed, thus squandering the spectrum’s enormous capacity and unnecessarily creating conditions of scarcity.

The Spectrum Collaboration Challenge (SC2), aimed to ensure that the exponentially growing number of military and civilian wireless devices would have full access to the increasingly crowded electromagnetic spectrum. Competitors reimagined spectrum access strategies and developed a new wireless paradigm in which radio networks autonomously collaborated and reasoned about how to share the RF spectrum, avoiding interference and jointly exploiting opportunities to achieve the most efficient use of the available spectrum. SC2 teams developed these breakthrough capabilities by taking advantage of recent advances in artificial intelligence (AI) and machine learning, and the expanding capacities of software-defined radios. Ultimately this competition aimed not only to challenge innovators in academia and business to produce breakthroughs in collaborative AI, but also to catalyze a new spectrum paradigm that will usher in an era of spectrum abundance.

The Technology

SC2 Competitors developed innovative solutions to autonomous spectrum management in the form of Collaborative Intelligent Radio Networks (CIRNs). These CIRNs reason and collaborate in order to automate the currently inefficient, labor-intensive process of spectrum management.

As a foundation for the competition, DARPA built the world’s largest RF emulator testbed for doing repeatable radio experiments, called Colosseum. Experimenters can connect up to 256 radios which transmit, receive and interfere with each other just as they would in the real world. DARPA also designed a series of RF scenarios designed to mimic the challenges that collaborative, autonomous radios will face in the real world. Finally, DARPA developed a custom visualization tool, which merges RF, spatial and scoring data into an interactive application to enable viewing and analysis.

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