Engineering researchers pave the way for more efficient radio spectrum sharing
January 7, 2016
BLACKSBURG — Television, radio, and wireless signals ride on a cluster of frequencies in the radio band of the electromagnetic spectrum, and the band is increasingly crowded.
The Federal Communications Commission is opening up bands of spectrum that were previously restricted to a few priority users, including the military.
Virginia Tech College of Engineering professor Jung-Min “Jerry” Park is leading a $730,000 National Science Foundation grant to find ways to make this transition as smooth as possible.
Imagine the military and the other priority users as dedicated swimmers in the lap lanes of a swimming pool, and the FCC just declared a free swim. Freeing up the spectrum will lead to innovation and new economic opportunities, but the influx of newcomers poses risks to the incumbent users such as dropped calls, degraded signals, radio jamming, and even piracy.
The FCC’s plans to provide incumbent users with a wide, insulating boundary, often called an exclusion zone, separating them from new users. In this type of environment, incumbent users have first dibs on the spectrum, and the secondary users can access what’s left over.
But the schema for divvying up the spectrum produces boundaries that are static and too large, squandering the spectrum’s potential to the tune of billions of dollars, according to some estimates.
The Virginia Tech project, called “Dynamic exclusion zones: Balancing incumbent protection and spectrum utilization efficiency,” is a collaboration with William Lehr from the Massachusetts Institute of Technology.
Park, of the Bradley Department of Electrical and Computer Engineering, and his collaborators intend to develop a new strategy supporting blueprints for flexible exclusion zones, or an adjustable boundary, that can respond dynamically to the incumbent protection requirements and the interference environment. In this way, incumbent users will still have safe, clear access to their frequencies, but secondary users will be able to make efficient use of the spectrum when it’s free.
“Our goal is to develop new frameworks for supporting dynamic exclusion zones that will enable much finer-grained, dynamic management of spectrum,” said Park. “The proposed framework expands opportunities for secondary users to coexist with incumbent users without causing harmful interference.”
The proposed models will account for terrain and other real-world environmental factors that might cause interference. The frameworks will also incorporate the economic challenges and incentives of managing shared spectrum access. By tailoring the boundaries of protection to the incumbent protection requirements and the needs of the secondary users, frameworks open up wide swaths of unused spectrum for new users, allowing for a safe and efficient use of a shared and finite resource.
Park is the director of the Laboratory for Advanced Research in Information Assurance and Security. The labs concentration is solving challenging problems in wireless networks and cyber security, with a particular focus on cognitive radio networks, related technologies for spectrum sharing, and their security implications.
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