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FCC Seeks Input on 3.5 GHz Spectrum Access System

I've previously reported on the FCC's plans for a “Citizens Broadband Service” in the 3550-3650 MHz band and now the FCC is looking for proposals on innovative ways to maximize the value of this 100 MHz band using a “Spectrum Access System”.

The commission had previously announced a workshop on Jan. 14 to explore the technical requirements, architecture, and operational parameters of its proposed SAS and seek public input on a minimum set of high level system requirements and functional parameters for the SAS. In advance of the Workshop, the FCC's Wireless Telecommunications Bureau and Office of Engineering and Technology are asking interested parties to submit papers discussing technical aspects of the proposed SAS.

The FCC's TV Bands Database systems that allow “white space” devices to operate on spectrum shared with TV broadcasters are a good example of how a Spectrum Access System could work. The SAS the FCC is proposing for the 3.55-3.65 GHz band would provide similar protection for existing users of that band. As the FCC Public Notice explains, several functions are required in the SAS. First, it needs access to updated location-specific spectrum usage and interference data. Second, it requires a baseline set of standardized methods for interpreting the data to determine allowable operation across the various tiers of users proposed for the 3.55-3.65 GHz band. Third, it must identify proper remedies to interference issues in a timely manner and communicate those back to operational network nodes. Finally, the SAS could use additional data from connected network nodes to monitor and if necessary, enforce compliance by participating network nodes.

The FCC Public Notice presents several questions:

•What should be the scope of the SAS’s responsibilities for enabling and de-conflicting use of the 3.5 GHz Band?

•How should these responsibilities manifest within a given tier (e.g., priority access, GAA) or between the different tiers?

•Should the SAS identify the available spectrum to authorize use in a particular location/frequency/time (similar to, but more expansive than the TV White Spaces approach) or should the SAS also manage the use of the band (i.e., configure and/or set limits on various radio parameters to maximize efficient use of the band)?”

Other questions include: “What are the key system elements of the SAS (e.g., database, signaling entities, etc.)? Who should have responsibility for each of these elements? Which system elements of the SAS require direct control by the Commission and which elements can be managed by third-party SAS provider(s) or other third parties? What level of oversight should the Commission exert over the functions of the SAS?”

For a complete list of the questions the WTB and OET are asking the papers to answer, see FCC Public Notice DA 13-2213.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.