Google, Microsoft Urge FCC to Rethink Channel 37 Limits in ‘White Spaces’ Order

Google, Inc., and Microsoft Corp. have each asked the FCC to reconsider aspects of its new rules for part 15 white space devices, with both raising concerns about rules governing channel 37 and Google raising additional concerns about requiring databases to “push” channel-availability information to unlicensed devices. Both companies said they supported most aspects of the FCC’s order and commended the Commission for promoting wireless broadband while protecting incumbent licensees from harmful interference.

But in a petition for reconsideration filed in ET docket 14-165 and GN docket 12-268, Google urged the FCC to reconsider and clarify the purpose and timeline for Channel 37 test deployments, including setting a target date for nationwide rollout of unlicensed operations in Channel 37. The FCC’s “highly conservative operating rules” for unlicensed devices operating in Channel 37 will “more than adequately protect Wireless Medical Telemetry Service incumbents” and created a waiver process by which WMTS operators “might as much as triple the applicable separation distance for white space devices,” Google recalled. 

“And yet, even while adopting these excessively restrictive rules for unlicensed use of Channel 37, the Commission created still more uncertainty for the unlicensed industry by stating that it intends first to limit test deployments of unlicensed services in Channel 37 to only one or two markets before authorizing nationwide roll-out,” Google said.  “Such uncertainty will undermine investment in the development of unlicensed equipment for use in the 600 MHz and repurposed television bands, and slow unlicensed network deployments.

“To foster certainty and stability, the Commission should therefore: (1) clarify that it will consider test deployment requests even before the deadline for health care facility registration has passed; (2) clarify that the Commission will consider reducing the generally applicable separation distances adopted in the Part 15 Order if test deployments indicate that reducing the separation distances will not cause harmful interference to WMTS, and that test deployments will not delay nationwide roll-out of unlicensed services in Channel 37 under the existing rules, and (3) establish a date by which it intends to authorize nationwide deployment of unlicensed services in Channel 37,” Google said.

In its petition, Microsoft said it understood the FCC’s desire to “proceed cautiously with co-channel operations on channel 37,” adding that it believes that “several of the new channel 37 rules for TVWS devices, while over-protective, could nonetheless permit innovation and investment in a channel that is currently unacceptably underutilized.”

But the order also “introduces, for the first time and without notice, several procedural restrictions that could preclude the reasonable use of channel 37,” Microsoft said.

“Because these measures were not discussed in the Part 15 NPRM, interested parties have not had a reasonable opportunity to comment on them,” Microsoft said.  “As a result, these unexpected rules fail to address several important issues, creating substantial uncertainty for potential investors in TVWS technologies about whether channel 37 will ultimately be usable at all, especially in urban areas where reliable spectrum access will be essential to support a viable ecosystem for TVWS technologies.”

Microsoft noted that the FCC, without prior notice, announced that it would limit initial deployment of white space devices using channel 37 to “one or two areas,” while at the same time promulgating a “comprehensive set of Part 15 technical rules that enable Part 15 operations on channel 37.  This discrepancy has created considerable confusion about both the purpose of the channel 37 trial period and the rules that will apply during and after the trial.

“The Commission spent more than two years accumulating a substantial record that supports the white-space rules it has now created for channel 37,” Microsoft said.  “It could not be the Commission’s intent to adopt these detailed technical rules, and, in the very same order, announce that it will revisit these same rules before they even go into effect after the channel 37 trial period has concluded. Indeed, doing so would not only scrap years of work by the Commission and industry to develop adequate operating rules for channel 37, but would create stifling uncertainty surrounding channel 37 operations for years to come.”

If the FCC decides to conduct test deployments to determine whether changes to the rules are needed, it should enable white-space devices to access channel 37 “pursuant to the operating rules it has just issued,” Microsoft said.  “If the tests determine that changes are necessary, as the Commission has recognized, protection criteria can be modified in particular circumstances based on new information.”

Microsoft called for several other clarifications regarding channel 37, including a clarification that the purpose of the trial period is “to specifically evaluate the actual interference risk between white-space operations and WMTS in dense urban environments, with a view to liberalizing the channel 37 rules to reflect the realities of these operating environments.”

Meanwhile, Google also argued that the FCC erred in requiring databases to “push” channel-availability information to unlicensed devices.  The Commission “correctly recognized in the Part 15 order that its initial proposal to require all unlicensed devices to recheck a TV white space database every 20 minutes would unnecessarily and substantially burden database operators and unlicensed devices,” it said.

Although the FCC “properly rejected its own initial proposal,” in its place, the Commission adopted an “even more flawed requirement that database administrators ‘push’ information to white space devices in the area where the licensed wireless microphones will be used, notifying them of changes in channel availability,” Google said.

“Adopted without prior public notice, this decision relies on the faulty assumption that having databases ‘push’ information to unlicensed devices in specified geographic areas would be less burdensome than having all unlicensed devices recheck or ‘pull’ information from a database,” Google said.  “Not only is the local ‘push’ requirement at least as burdensome as a general ‘pull’ approach, but also it will not be feasible for database operators to ‘push’ information to all categories of unlicensed devices.”

Google said the FCC should reconsider this decision and instead adopt the “fast-polling” channels solution that the company had proposed earlier.

Under the fast-polling approach, the FCC could “protect licensed wireless microphone use in breaking news situations by identifying two ‘fast-polling’ channels,” Google said.  “On just these two channels, unlicensed devices would be required to query the database every 20 minutes to check for wireless microphone reservations that must be quickly accommodated, while allowing the majority of unlicensed devices operating on other channels to continue to check the database daily.” —Brian Hammond, brian.hammond@wolterskluwer.com

Courtesy TRDaily