AT&T, Cellular South debate 700 MHz interoperability at FCC

WASHINGTON--Representatives from Verizon Wireless (NYSE:VZ), AT&T Mobility (NYSE:T) and other large companies argued that mandating interoperability across different band classes of the 700 MHz band will be costly and difficult to achieve. On the other side, smaller carriers and consumer advocates argued that, without interoperability, subscribers of smaller carriers will suffer from more expensive devices and a lack of roaming.

The FCC convened a workshop here to explore both the commercial and technical issues related to 700 MHz interoperability. The issues are incredibly complex, but are growing more urgent as more carriers begin deploying LTE networks in 700 MHz spectrum. Smaller and rural carriers have claimed that Verizon and AT&T are ordering LTE equipment that will not work with the band classes of 700 MHz spectrum they own, effectively shutting them out of the growing LTE ecosystem.

Verizon acquired most of the FCC's 700 MHz C Block spectrum (which lies in band class 13), and many of AT&T's 700 MHz licenses sit in the lower C and B Blocks (which lie in band class 17). A number of smaller operators acquired 700 MHz spectrum licenses in the Lower A, B and C Blocks, which lie in band class 12. 

An alliance of smaller carriers called the Good Faith Purchasers Alliance, which is a joint venture among Cellular South, Cavalier Wireless, Continuum 700 and U.S. Cellular, has urged the FCC to require network and handset suppliers to build gear that can work across all 700 MHz bands.

Eric Graham, Cellular South's vice president of strategic and government relations, said smaller carriers are being forced to source devices at a much smaller scale than they ever have before, since the 700 MHz band is the only spectrum band with multiple band classes in the U.S. He said dual-chipset solutions that support legacy networks and LTE in band class 12 should be commercially sampling in September, months behind Verizon. He said there is currently no timeframe for commercial samples of single chipset solutions. "Without interoperability, we will continue to see this lag," he said.

Michael Chard, senior director of business development for Qualcomm's (NASDAQ:QCOM) chip business, said the company intends to develop single chipset solutions for band 12, but he did not say when those products would be available. Qualcomm will ship commercial samples of a chip that supports the band class 12 plus cellular, PCS, and AWS in September. He said that currently Qualcomm's chips cannot support multiple 700 MHz band classes, and that the development of such chipsets could take years to complete and is contingent on carrier demand.

Stacey Black, assistant vice president for market development at AT&T, said a 700 MHz interoperability mandate would force carriers to reconfigure their LTE device plans, and would slow the adoption of LTE devices. He also said carriers would have to deploy multiple base stations to counteract interference. Matt Wood, associate director of the public interest group Media Access Project, countered that without interoperability wireless customers wouldn't be able to easily move from one carrier to another.

Bill Stone, Verizon's executive director of network strategy, said the carrier wants to support multiple bands for international roaming and capacity reasons. However, he said supporting multiple 700 MHz bands will increase the number of components in devices, and thus the size and cost. Stone predicted it would be at least six months before band class 12 devices are commercially available.  

Gene Fong, a Qualcomm senior staff engineer, said the company's chipsets are able to currently support no more than two bands below 1 GHz and three bands above 1 GHz, but that the company is working to change that. He said supporting all of the various LTE bands is "incredibly complicated."

"The number of bands we see is exploding," he added, pointing to the diverse bands across the world being used for LTE. "It far outstrips what we feel as practical in terms of a device." Fong added that he does not see software-defined radios as "a near-term solution for this particular problem."

Special Report: Will the FCC require all 700 MHz LTE equipment to interoperate?

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Article updated April 26 to clarify Qualcomm's stance on support for multiple 700 MHz bands. The company's chipsets currently support multiple frequency bands, but due to technical limitations do not currently support multiple 700 MHz band classes.