AT&T, Gogo trade barbs over power levels in 800 MHz band

Representatives of in-flight wireless Internet provider Gogo recently met with FCC officials to discuss what the company describes as "potentially misleading claims" made by AT&T (NYSE: T) in support of AT&T's petition for a waiver of FCC rules related to power requirements in the 800 MHz band.

Gogo is concerned because adoption of a power spectral density (PSD) proposal for operations in the cellular band would increase the risk of out-of-band emission (OOBE) interference to its operations in the neighboring 800 MHz air-to-ground (ATG) band. Gogo is urging the commission to adopt more stringent OOBE limits on cellular operations near 800 MHz ATG base stations.

"Contrary to AT&T's assertions, if the FCC grants the Petition, AT&T would operate at power levels higher than currently allowed under the rules," Gogo said in an ex parte filing with the FCC. "Specifically, if AT&T was to deploy a five megahertz LTE carrier in the cellular band tomorrow, its power limit would be 100 watts/megahertz. But AT&T is seeking to deploy five megahertz LTE carriers at a maximum power of 500 watts/megahertz, a five-fold increase over the current limits."

Gogo added that "AT&T's sophistry relies on an apples-to-oranges comparison, which analogizes narrow-band GSM operations, which pose little threat to OOBE interference, to wide-band LTE operations. As Gogo explained during the meeting, narrow-band technologies such as GSM have much sharper 'roll-off' than wider-band technologies, and thus produce much lower out-of-band emissions."

For its part, AT&T is not backing down. "The FCC's rulemaking explains why an examination of the power measurement is necessary," AT&T said in a statement to FierceWirelessTech. "Further, our proposal does not exceed the same power per sector as is allowed under current rules for narrowband networks, and we, of course, intend to fully comply with the FCC's OOBE rules."

The FCC issued a public notice in December asking for comments on AT&T's request for a limited waiver of commission rules to permit the use of a PSD model in eight markets in Kentucky and Tennessee pending the outcome of an ongoing rulemaking proceeding to modify the rule. AT&T proposed a PSD limit of 250 watts/MHz in non-rural areas and 500 watts/MHz in rural areas and presented two studies to show that implementing PSD-based power limits in the cellular service area would not cause harmful interference to public safety deployments.

In Jan. 11 comments submitted to the commission, AT&T said comments filed by Gogo and the National Public Safety Telecommunications Council (NPSTC) presented insufficient justification to delay granting a waiver. 

In its Jan. 20 filing, Gogo also said it's primarily concerned with the increased risk of harmful interference, which will inevitably result from grant of PSD power limits in the cellular band. "AT&T has attempted to side-step this issue by implying that Gogo is seeking relief to currently existing interference," Gogo states. "But AT&T is incorrect. Gogo is working wth AT&T and other cellular licensees outside of this proceeding to address interference as it occurs."

Gogo urged the FCC to promptly allocate and auction spectrum for the proposed 14 GHz Air-Ground Mobile Broadband Service, as it needs additional spectrum capacity to provide in-flight broadband and other services. Gogo's filing was submitted by Hogan Lovells attorney Michele Farquhar, who was chief of the FCC's Wireless Telecommunications Bureau from 1995 to 1997.

Interestingly, a couple years ago it looked as though AT&T was going to get into the in-flight wireless business and compete head-to-head with players like Gogo, Inmarsat and others. The plan called for using WCS C and D Block spectrum to provide in-flight Wi-Fi services, but AT&T changed its mind and decided not to pursue that business.

For more:
- see this Gogo filing
- see this AT&T filing

Related articles:
Gogo Wireless CEO: 2016 will be ramp year for 2Ku in-flight Wi-Fi technology
Qualcomm, Gogo, others continue to push for FCC's 14 GHz ATG spectrum auction despite moves to satellite services
Gogo would be 'happy' to talk with AT&T about leasing spectrum, CEO says
AT&T kills plan to use LTE in WCS C, D Block for in-flight Wi-Fi services

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