5 GHz Devices Using DFS Pass Field Tests in Tex.
Devices operating on 5 GHz using dynamic frequency selection (DFS) technology passed NTIA field tests recently in Tex., easing concerns about whether they can peacefully coexist with military radars, according to sources familiar with the tests. However, one manufacturer had some problems in an earlier lab test conducted by NTIA in Boulder, Colo.
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“They did bench testing at the NTIA lab in Boulder and then they went down to Tex. and did field testing with real radar,” one industry source said. “That testing went extremely well. All the radars passed.” The source added: “They were trying to see if the devices work. The other thing they were trying to determine is if the bench test was a good test.”
If all goes as planned, a committee made up of representatives from NTIA, the FCC, the Dept. of Defense and other agencies is expected to approve a process in Feb. that would lead to certification of the first devices operating at 5 GHz, using DFS, sources said. The first devices could be on store shelves next year.
The FCC and NTIA hope to make available 255 MHz of spectrum in the 5.470-5.725 GHz band for unlicensed use through DFS. DFS “dynamically” tells a transmitter to switch to another channel when a interference is encountered, such as detection of a radar signal. Devices using DFS also monitor the availability of unobstructed spectrum prior to transmitting. Since military radars also operate around the band, potential interference has sometimes become a contentious subject as FCC and NTIA examined DFS.
NTIA Dir. Michael Gallagher said in an interview NTIA was still examining the test results. Gallagher earlier said that 5 GHz spectrum will provide more capacity and more channels to handle the increased data flow expected by consumers. “When Airgo can do 240 Mbps over a Wi-Fi chip, when you have large video files being transferred between users… that’s the type of capacity that’s going to be needed to meet the growth expectations moving forward,” he said.