4G on the Baby-Monitor Frequency

Early next year in a swath of northern Florida, as many as 8,000 people will be able to get 4G wireless broadband with a twist: the service will beam over a frequency normally used by gadgets like garage-door openers and baby monitors.

The project at Northeast Florida Telephone, using gear from a startup called XG Technology of Sarasota, Florida, appears to be the first commercial use of cognitive radio, which senses available frequencies and switches between them on the fly. Cognitive radios are now used mainly by the military. The technology is one of many creative approaches that will be needed to forestall a spectrum shortage triggered by the boom in super-fast smartphones. Other companies are filling gaps with something called "super Wi-Fi," tapping unused parts of the TV spectrum (also often called white spaces) to deliver service. But those frequencies become available only with advance notice, not on an instant, real-time basis.