Cognitive Radios React to Environment for Better Public Safety Communications
Software-defined radio and cognitive radio are two related developments in radio technology. Radios were once built from analog electronic parts and circuits that handled signal processing. With the advances in digital electronics over the past few decades, however, radios have become more like computers. This switch to digital is important because digital parts and circuits are usually much less expensive than analog and because an analog system can usually do only a few tasks, whereas a digital system can be programmed do many different tasks defined by the software it uses.
NIJ is funding a project at Virginia Tech to create better radios that will help law enforcement officers in various ways. The new "cognitive" radios will be programmed to recognize when a particular radio frequency is overloaded with traffic and will automatically find and switch to an alternative frequency when needed, without requiring any action from the operator. A cognitive radio is “aware” of its environment, its own capabilities and limitations, and its operator’s needs.
Cognitive radios run under the control of a software package called a “cognitive engine.” This engine does many things an intelligent human would do, freeing law enforcement officers to do their primary jobs.
One application for cognitive radio is dynamic frequency sharing. Radios can find and use open frequencies (“white space” in the radio spectrum) or share channels based on a priority system. This can give law enforcement access to more spectrum when needed and allow sharing of public safety channels with others during idle times.
In an NIJ project at the Stevens Institute of Technology, researchers are working to develop cognitive networking protocols and software radio devices that will dynamically bond multiple wireless interfaces to create a virtual broadband network. This will allow an officer to communicate with other officers on different wireless networks simultaneously. It will also support video streaming, which might not be supported on any single radio network because of bandwidth constraints.
