AT&T to rural carriers: Seek LTE interoperability with Sprint, T-Mobile

AT&T (NYSE:T) responded to the newly renamed Competitive Carriers Association's push for 700 MHz interoperability by suggesting, among other things, that CCA members should be seeking seamless coverage across the LTE deployments of Sprint Nextel (NYSE:S), T-Mobile USA and A-Block carriers instead of demanding interoperability with AT&T.

Band Class 12 includes the Lower A Block 700 MHz spectrum held by small licensees, while AT&T holds Lower B and C Block 700 MHz spectrum in Band Class 17. AT&T has said it worked with 3GPP to create Band Class 17 to guard against interference from Channel 51 broadcast transmissions adjacent to the Band Class 12 Lower A Block spectrum. But small operators are calling for the FCC to force interoperability across all paired spectrum blocks in the Lower 700 MHz band, saying that will better enable nationwide roaming and broader device availability.

"A Band 12/17 combination is but one option for 700 MHz A Block licensees," said Joan Marsh, AT&T vice president of federal regulatory, in an entry on the operator's Public Policy Blog. The FCC should not mandate that option "while ignoring all the other LTE band class combinations that could provide A block licensees with broad LTE support," she added.

For example, small operators cannot rely on Sprint's LTE deployment in the PCS G block unless a Band 25 chip set is built into their LTE devices or T-Mobile's planned AWS-1 LTE deployment absent use of a Band 4 chipset, said Marsh.

That argument appears particularly pertinent given that T-Mobile and Sprint are among the CCA's newest members, and mandated Band 12/17 interoperability would have no impact on enabling fellow CCA members to roam onto those two operators' LTE networks.

The CCA was known as the Rural Carriers Association (RCA) until earlier this month, an acknowledgement of the fact that the group's revised bylaws allow carrier members with fewer than 80 million subscribers rather than the former benchmark of 10 million. In June, the CCA added Clearwire (NASDAQ:CLWR) to its membership roster. Last March the group added T-Mobile USA as a member, and last year it added Sprint Nextel.

"A device that supports LTE Band 12, 25 and 4 would provide RCA members with seamless coverage across the LTE deployments of Sprint, T-Mobile and the A-Block carriers. Perhaps that is the solution that RCA should be pursuing," wrote Marsh.

On Sept. 10, the same day it announced its new name, the CCA joined with a new group called the Interoperability Alliance, to push for 700 MHz interoperability. The alliance also includes small businesses, trade associations and consumer interest groups.

Grant Spellmeyer, executive director of federal affairs and public policy for US Cellular, alleged in a release touting the alliance's formation that AT&T's decision to deploy LTE "on a separate, unnecessary band class" has erected barriers to seamless connectivity and fractured the device ecosystem.

However, AT&T's Marsh attempts to counter such arguments by noting, "LTE is currently being deployed both domestically and globally on a multiplicity of different spectrum bands and the deployments are and will remain fragmented across bands. Every carrier, regardless of size, will have to rely on multi-band chipset solutions to provide full LTE coverage."

There are in excess of 25 LTE FDD band classes, said Marsh. Like T-Mobile, MetroPCS' (NYSE:PCS) AWS-1 LTE deployment requires a Band 4 chipset, CSpire requires a Band 5 chip set, while deployments in the future AWS-4 bands being eyed by Dish Network will require a Band 23 chip set and LTE in Clearwire's 2.5 GHz spectrum requires a Band 41 chipset. Further, deployments in 700 MHz spectrum require a Band 12 (US Cellular), a Band 13 (Verizon) or a Band 17 (AT&T) chipset, depending up the spectrum blocks supported, she said.

"If you are deploying in multiple bands, as most carriers will be required to do, you'll need to support multiple band classes domestically, and a few more internationally if you want to support LTE roaming around the globe," said Marsh.

The FCC initiated a proceeding in March 2012 regarding a proposed rulemaking on 700 MHz interoperability. The proceeding could be completed by year's end.

For more:
- see this AT&T blog entry
- see this Interoperability Alliance release

Related articles:
RCA becomes the Competitive Carriers Association
AT&T: 700 MHz interoperability proposal unnecessary, unprecedented
Paul Allen's Vulcan Wireless peddles 700 MHz interoperability framework
C Spire sues AT&T, others for allegedly blocking its 700 MHz plans
Qualcomm at work on chip to support multiple 700 MHz bands
RCA abandons handset exclusivity fight in favor of 700 MHz interoperability