The Bluetooth Special Interest Group (SIG) backed up its previous assertions that terrestrial low power service (TLPS) interferes with Bluetooth with a series of more detailed reports filed with the FCC.
The filings come in a proceeding whereby the FCC is considering whether to allow Globalstar to use spectrum in the 2.4 GHz band for TLPS services. Globalstar earlier refuted the Bluetooth SIG's claims about interference. Globalstar walked away from the tests, which were conducted in early March at the FCC's Technology Experience Center (TEC) in Washington, D.C., with the belief that its tests showed no negative impact on Bluetooth. Separate tests were conducted over a series of days.
Not surprisingly, Bluetooth SIG argues that the demonstrations it conducted at the FCC "firmly indicate and further validate all the Bluetooth SIG concerns raised throughout the Globalstar NPRM process" and through previous Bluetooth SIG filings to the FCC.
The way the tests were conducted is significant because Globalstar has come under fire for earlier test results, as well as for a lack of transparency in how it conducts tests. This latest round of tests was conducted at the FCC, with FCC staff present, as well as representatives from the Bluetooth and Wi-Fi industries, two technologies likely most directly affected by what Globalstar is proposing to do.
Bluetooth SIG said that throughout the March 6 demonstration, there were many unknowns about the four access points (APs) on channels 1, 6, 11 and 14 and equipment provided by and "preconfigured" by Globalstar. "It was evident that Globalstar had the test configuration perfectly suited and controlled to reflect what best suited their test requirements. In a more adequate and real world test environment, both sides of the equation must have equal access to configure, modify the test parameters, adjust spectrum traffic, adjust the AP streaming traffic/throughput to the client devices (not only use the preconfigured data stream of 3.7 Mbps provided by Globalstar), adjust output powers, etc."
Earlier, Bluetooth SIG reported that the demonstrations showed that the packet loss experienced by Bluetooth hearing aids jumped from 10 percent to almost 20 percent with TLPS present; packet loss over 10 percent would cause significant audio disruption for the user. "Smart" lighting demonstrations also showed that the number of instances where the smart lights failed to receive commands increased about four times with TLPS present.
The Bluetooth SIG is asking the FCC for additional public, "properly constituted," test events in order to derive quantitative data. "The configuration of the test environment can be an agreed upon effort between Globalstar and the others," it said.
Globalstar argues that the Bluetooth SIG representatives chose to demonstrate only two devices despite having additional devices at the TEC. Globalstar says its demonstrations showed that Bluetooth-enabled devices, including a heart rate monitor, wireless speaker and various computer mouses, worked without any service impact in the presence of TLPS.
The National Cable & Telecommunications Association (NCTA) and CableLabs also participated in tests earlier this month, but Globalstar doesn't think the FCC should give CableLabs' test results much weight--or rather, any weight whatsoever.
In an ex parte filing, Globalstar said that during meetings with FCC staff after the tests, Globalstar executives "further pointed out that CableLabs' TLPS/Wi-Fi demonstration set-up was in no sense representative of a real-world deployment, and that any results provided by CableLabs in this proceeding should be entirely discounted."
"CableLabs requested that Globalstar take down its network of access points in the TEC in order to 'sandwich' an inexpensive Belkin access point operating on Channel 11 between multiple Channel 6 access points and multiple TLPS-enabled access points, all within a few feet of one another," Globalstar said. "The Commission should disregard this contrived attempt to force a negative impact on Wi-Fi Channel 11."
NCTA expects to submit a follow-up report to the FCC by April 17.
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