FCC Will Push for Spectrum Sharing in 3.5 GHz Band to Support Mobile Small Cells

The Federal Communications Commission will, by the end of 2012, initiate formal steps to authorize spectrum sharing in the 3.5 GHz band, potentially adding about 100 megahertz worth of spectrum intended to be used to support mobile network small cells. 

The set of frequencies between 3550MHz and 3650MHz is currently used in radar systems but could be shared with other wireless services. It would possibly be a complex undertaking.

However, in order for the government to keep using the spectrum for radar systems, other uses would have had to be blocked for about 200 miles inland from all U.S. coastlines, leaving out a majority of the country's residents, PCAST said in its report. A spectrum-sharing system could dramatically shrink or eliminate those exclusion zones, the group said.

Because of its high frequency, the 3.5GHz band would be better suited to fixed wireless Internet service than to mobile, according to Farpoint Group analyst Craig Mathias. 

“Sharing is a long-term process, and we are at day one of a long journey,” analysts at  Rysavy argue. Currently, there are three sharing models:

• Geographic sharing, in which a wireless carrier may use a federal agency's frequencies only in certain geographic areas;

• “Temporal” sharing, in which a wireless carrier may use a federal agency's frequencies only during certain times of the day or year; and

• Technology-based sharing, in which wireless carriers and a federal agency would each use a cognitive, or “smart,” radio device that can search wide swaths of a spectrum band for “quiet,” or unused, frequencies over which to transmit and receive data.

Such operations can be complex, many would note.