How Spectrum Sharing Would Work

The President's Council of Advisors on Science and Technology recent report alludes to spectrum-sharing technologies that would help address the exploding demand for mobile data spurred by smartphones and tablets. How exactly would this spectrum-sharing technology work? Steven Crowley, a wireless engineer who works as a consultant to carriers, government agencies and others, said that the system should be designed so that federal, nonfederal and commercial entities can share available radio spectrum. In order for something like this to work, the government would need to use a centralized system to scan the radio waves and be aware of the spectrum environment. This system would be able to find which frequencies are available and choose the best one for a mobile device to make a connection. Mobile devices themselves can also be equipped with special sensing circuitry to detect what frequencies other cellphones are using, and to choose a frequency that is less crowded, he said. More advanced antennas would also help with this effort, Crowley said. A conventional radio antenna on a cellphone tower spews energy in all directions, but only a portion of it goes to the right phone. A technology called the smart antenna would direct energy straight at phones, and as a result, current spectrum would be put to more efficient use. The idea of sharing unused spectrum seems fairly obvious, raising the question of why it hasn’t already been done. Crowley said the technologies required for spectrum-sharing had only recently matured.