700 MHz Interoperability Comments
Verizon, AT&T: FCC should focus on resolving interference concerns
in lower part of the 700 MHz band, which will enable greater
RCA--The Competitive Carriers Association:FCC should set deadlines for
carriers to offer mobile devices that can operate across all paired spectrum
blocks in the lower part of the band
By Paul Barbagallo
The wireless industry remains divided on whether new regulations are needed
to ensure that mobile devices used in the lower 700 megahertz band of spectrum
can operate on airwaves used by different carriers, including Verizon Wireless
and AT&T Inc.
In comments filed with the Federal Communications Commission, carriers large
and small staked out familiar positions on an issue that will factor heavily in
the agency's effort to reclaim hundreds of megahertz of spectrum for mobile
broadband and similar applications over the next decade.
“The commission should act quickly to make interoperability in the lower 700
MHz band--and eventually across the entire 700 MHz band--a reality,” RCA--The
Competitive Carriers Association wrote in a filing dated June 1. “The commission
has the legal authority to implement an interoperability mandate, and doing so
is strongly in the public interest.”
The association and a number of its members--wireless carriers serving mostly
smaller, more rural parts of the country--have alleged that Verizon and AT&T
are pressuring manufacturers of handsets, chipsets, and network equipment to
make their products compatible only with Verizon- and AT&T-occupied spectrum
in the 700 MHz band.
The carriers have argued that absent FCC action, their customers will be
deprived of the latest smartphones and the ability to roam on Verizon and
“The persistent lack of interoperability in the lower 700 MHz band since the
close of Auction 73 has significantly impacted the availability and cost of
equipment and devices to A Block licensees,” wrote Vulcan Wireless LLC.
In that auction, in 2008, Verizon acquired most of what is known as the “C”
Block, paying $9.6 billion for 108 licenses. AT&T bought 227 licenses for
$6.6 billion in the “B” and C blocks. A number of smaller mobile network
operators purchased licenses in the lower A, B, and C blocks.
After the auction, the 3rd Generation Partnership Project, an industry
standards-setting body known as the 3GPP, created four band classes within the
700 MHz band--12, 13, 14, and 17. Band class 13 was designated for Verizon's
upper C Block spectrum; band class 17 for AT&T's lower B and C block
spectrum; and band class 12 for the smaller operators' lower A, B, and C block
spectrum. Band class 14 was created for the upper B Block and spectrum allocated
for public safety use.
As of right now, all handsets, chipsets, and network equipment made for band
class 13 are incompatible with band class 17 or band class 12, and vice versa.
And most manufacturers are making gear only for Verizon and AT&T.
To remedy the situation, Vulcan is urging the FCC to require wireless
carriers to upgrade their base stations to support interoperability across the
entire lower 700 MHz band within six months of a final FCC ruling.
With nine months of that ruling, any carrier offering at least one mobile
device “that is capable of operating on any paired spectrum block within the
lower 700 MHz band” would have to commercially offer and support, in each market
in which the carrier offers service, at least one mobile device that can operate
across all paired spectrum blocks in the lower part of the band, under Vulcan's
Then, within 18 months, all devices would have to be interoperable in the
lower 700 MHz band.
“Without readily available equipment that works across the lower 700 MHz
band, lower A block licensees cannot attract potential retail or wholesale
customers or provide commercially viable service on their lower A block
spectrum,” Vulcan said.
But to Verizon and AT&T, regulatory mandates would undermine the
standards processes at the 3GPP.
In rebutting the claims of smaller carriers, both companies argued that one
of the underlying reasons for separating the 700 MHz blocks into different band
classes is interference--the proximity of A Block spectrum pairs to TV broadcast
transmissions on one hand, and high-power broadcast transmissions in the
unpaired 700 MHz D Block and E Block on the other.
“The high power broadcasts permitted in broadcast TV channel 51 and in the
700 MHz lower 'E' Block create the potential for debilitating interference into
the lower A and B blocks that could dramatically degrade wireless service.
Indeed, these interference concerns led to the creation of 3GPP Band 17, which
allows carriers to operate in the B and C blocks while filtering out the
interference from the high-power transmissions adjacent to the A block,”
AT&T explained in a blog post June 1.
In official comments, AT&T said that an interoperability mandate is
“Manufacturers can and already do create Band 12 variants of LTE devices
designed for other 700 MHz bands at negligible additional cost,” AT&T said.
One carrier, US Cellular, has already announced the introduction of a number of
Band 12 devices and its intention to bring more on line this year, the company
But even if it did exist, an AT&T “Band 12 device” would be unusable
anyway, it said.
AT&T's LTE devices will all “fall back” to GSM technologies (GSM is short
for Global System for Mobile Communications, the world's most common wireless
Most A Block carriers use the CDMA standard, or Code Division Multiple
For this reason, AT&T said, US Cellular's Band 12 LTE devices are
“variants” of Verizon's Band 13 devices, since Verizon uses the CDMA
But some smaller wireless carriers believe that without interoperability, not
only will they lack 700 MHz band handsets to sell to their customers, their
customers will not be able to roam onto Verizon's and AT&T's 4G LTE
AT&T disagrees, noting that 4G devices are “increasingly multi-band
“Indeed, no carrier is likely to offer LTE on a single band and thus all will
have to develop devices that support multiple bands,” AT&T said.
Like AT&T, Verizon advocated for a industry-led solution, rather than new
To Verizon, the FCC could enable greater interoperability of devices by
encouraging broadcasters on Channel 51 to relocate voluntarily in advance of
so-called “voluntary incentive auctions” authorized by the Middle Class Tax
Relief and Job Creation Act of 2012.
The FCC could offer broadcasters “first choice” in the relocation process
and, for those broadcasters that elect to participate in the auctions, a premium
on their bids to sell, Verizon said.
“Once the issues arising from Channel 51 operations are eliminated, an
industry solution is likely to emerge for interoperable equipment in the lower
700 MHz band without the need for equipment mandates,” Verizon wrote in
Weighing in with the manufacturer's perspective, Qualcomm told the commission
that is working to design chipsets that “support the entire Lower 700 MHz band,
mitigate interference, and improve interoperability.”
At the same time, Qualcomm warned the agency that the lower 700 MHz band
presents “unprecedented interference challenges.” Without proper filtering, the
company said, a consumer device operating in B and C blocks would suffer
blocking interference from E Block signals, intermodulation interference when
the E Block signal combines with its transmit signal, and reverse
intermodulation interference because of TV Channel 51.
“Qualcomm has not found an acceptable solution to these interference
challenges,” it wrote. “Furthermore, unfortunately, the mitigation techniques
suggested by A Block licensees will not work and studies purporting to show that
these interference concerns are manageable are deeply flawed.”
Qualcomm said that the FCC should conclude that harmful interference from
both the E Block and Channel 51 would “unacceptably degrade” consumer devices
operating in the B and C Bands without the Band 17 filter in place.
“The company still does not have an interoperability solution that protects
consumers from harmful interference--and creating one, if this outcome were
mandated by the Commission, would take years, increase costs, and still yield
consumer device degradation,” Qualcomm said.
To read the comments, visit http://apps.fcc.gov/ecfs/comment_search/input?z=qglon
and type in Docket No. 12-69.