Microsoft: Tests show Globalstar’s TLPS would have ‘profound negative impact’ on video game consoles

Microsoft tlps
Included in Microsoft's FCC filing are images of its test setup. This one shows a SORA software defined radio being used as part of the demonstration. Source: Microsoft

Microsoft said that tests it conducted at its campus in Redmond, Washington, show that Globalstar’s proposed terrestrial low power service (TLPS) would have a ”profound negative impact” on Xbox 360S video game consoles.

The FCC granted permission to Microsoft back in May to test terrestrial operations in the 2473-2483.5 MHz unlicensed band and the adjacent 2483.5-2500 MHz band, consistent with Globalstar's proposal to operate TLPS on these frequencies nationwide. Microsoft wanted to quantify the effect of such operations on the performance and reliability of unlicensed operations in the 2.4 GHz ISM band.

This week, Microsoft provided the FCC with a detailed presentation outlining the tests it conducted, the equipment used and the results.

“The implications of these results are clear. If the Commission grants Globalstar permission to operate TLPS, or grants even wider use of the frequencies to other services, a broad cross-section of U.S. consumers will lose functionality of their current gaming devices,” wrote Paula Boyd, director of government relations and regulatory affairs, and Michael Daum, technology policy strategist, in a Microsoft filing (PDF).

Total sales of Microsoft’s Xbox 360S series of consumer home entertainment consoles are approaching 100 million units worldwide, with about half of the customers residing in North America.

“Microsoft has no reason to believe that other game console manufactures operating in the 2.4 GHz ISM band would not be similarly affected,” Boyd and Daum wrote in the filing. “Based on experimental data, and given the total number of consumers that would experience harm, Microsoft therefore requests that the Commission not permit Globalstar TLPS or opportunistic Wi-Fi use of channel 14 in the 2.4 GHz ISM band.”

Specifically, Microsoft measured the frequency with which a button press on a wireless controller failed to communicate with the console, causing it to not to behave correctly in response to user input, or what they term as “button loss.” Button loss degrades the game player user experience, and – if serious enough – can render a game unplayable. The Xbox 360S specification provides, therefore, that button loss shall not exceed 1 loss in 10 minutes of operation.

The company's tests showed that the introduction of a nearby Globalstar TLPS transmitter using the IEEE 802.11 protocol led to a button loss in Xbox game controllers of over 6 percent, or more than 100 times over 27 minutes. That’s 38 times worse performance than the product specification allows, according to Microsoft.

Microsoft’s results are not surprising. The company previously blasted Globalstar for making what it called misleading claims about tests showing no interference between TLPS and Wi-Fi, nor with TLPS and Bluetooth operations in the 2.4 GHz ISM band. Microsoft also pointed out that Globalstar's Chicago and FCC Technology Experience Center demonstrations used an enterprise-grade Ruckus model, which Microsoft doesn't think is representative of most of the Wi-Fi access points out there in the world.

Microsoft’s tests are also noteworthy because commenters in the FCC's Globalstar proceeding have complained that tests so far were inadequate. Microsoft conducted two series of tests, one qualitative and the other quantitative.

For more:
- see this Microsoft filing (PDF)

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