White Spaces Proponents Say FCC FNPRM Appears to Ask Right Questions
The biggest change between the draft TV white spaces order and the item approved 5-0 by commissioners Tuesday (see 2010270034) was the addition of a Further NPRM on how the agency can modify its rules to permit use of terrain-based models, such as the Longley-Rice Irregular Terrain Model, to determine available TV channels for white space devices. “By accounting for terrain features, such models could make additional spectrum available for unlicensed broadband services,” the order said.
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The FNPRM is “very thorough,” said Michael Calabrese, director of the Wireless Future Program at New America, Thursday. “Our public interest and rural broadband coalitions were pleased to see the FNPRM seeks comment on our proposal to allow the TV bands database to take real-world terrain into account when it grants or denies permission to operate on a [white spaces] channel,” he said: “The current rules were adopted a decade ago and are overprotective and arbitrary in ways that undermine the ability of [wireless] ISPs, school districts, libraries and other potential … users to narrow the digital divide.”
The FNPRM “points out a terrain-based propagation model could permit TV white space devices to deploy in more geographic areas, such as at locations where the television signal is shielded by a large hill or mountain, because the current methodology does not account for such shielding,” said Louis Peraertz, Wireless ISP Association vice president-policy.
The order itself changed relatively little, based on a side-by-side comparison (see here and here). “We recognize parties’ arguments that more sophisticated propagation models could possibly identify unused TV spectrum more accurately than the current contour-based model while still protecting TV service from harmful interference,” the order said. It cites comments by WISPA, the Public Interest Spectrum Coalition and the Dynamic Spectrum Alliance.
The biggest change is the addition of an FNPRM seeking "comment on the effect use of such a model would have on availability of channels for white space devices, how a terrain-based model such as Longley-Rice could be implemented within the current white space device framework, the technical parameters necessary to use such a model for identifying available spectrum while protecting incumbents from harmful interference, and various database and device implementation issues.”
“As a threshold matter, we seek comment on whether using a terrain-based model, and in particular the Longley-Rice model, would better serve the white space device community as well as television broadcasters and other protected entities in the television bands,” the FNPRM said: “Commenters should specify the pros and cons of their preferred approach as it relates either to the Commission’s existing contour method or other terrain-based propagation models.”
The final order offers a concession to wireless mic maker Shure. “As suggested by Shure, we are clearly indicating in the rules that mobile devices may operate only in ‘less congested’ areas by adding this requirement to the definition of ‘mobile white space device,’” the order said.
While the FCC proposed to require a mobile device “operating within a geo-fenced area to re-check its geographic coordinates at least once every 60 seconds and to cease operation if it travels closer than 1.6 kilometers to the edge of the geo-fenced area or is outside the boundary of the area, we agree with Shure that this proposed distance should be slightly increased to account for vehicles traveling at allowable highway speed limits,” the order said. Other changes in the order involve the FNPRM.
A side-by-side comparison of the 5G Fund draft and final orders found only minor changes. The order was approved Tuesday over partial dissents by FCC Democrats.