Practical Advice for Meeting the FCC's DFS Testing Requirements
by Juan Martinez and Tom Wetzel
Author's Note: The intent of this article is to share some practical advice on how to achieve compliance with the FCC's new dynamic frequency selection (DFS) requirements. However, in order to provide some general background information on this subject, the article begins with an excerpt from the article "Dynamic Frequency Selection and the 5 GHz Band," written by our colleague Mark Briggs and originally published in Conformity in December 2005.
The advent of the 802.11a wireless market and the constant push to open up new spectrum for unlicensed use created a requirement for dynamic frequency selection (DFS), a mechanism to allow unlicensed devices to share spectrum with existing radar systems. The regulatory requirements for DFS, along with requirements for transmit power control (TPC) and uniform channel loading have been adopted in the United States, Europe and Japan and are being considered by many other regulatory domains looking at adopting the 5GHz bands for unlicensed (and possibly licensed) devices.
Some Background on DFS Requirements in the United States
The Federal Communications Commission (FCC) had already opened up the 5150 - 5350 MHz band when it adopted the UNII rules into Part 15. The FCC opened up the 5470 - 5725 MHz band by working with industry and the Department of Defense through the U.S. Department of Commerce, National Telecommunications and Information Administration (NTIA), and released its Report and Order FCC 03-287 . To release the 5470 - 5725 MHz, a requirement for DFS was proposed to cover the new band and the existing 5250 - 5350 MHz band. The timing and threshold requirements were identical to those of EN 301 893 v1.2.3, but the signal parameters were different and included a frequency hopping radar.
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