updated 10:50 pm EDT, Wed May 30, 2012
AT&T fires back
Several regional carriers, including US Cellular and MetroPCS, have filed a report with the Federal Communications Commission that calls into question AT&T's justification for avoiding interoperability between LTE networks that operate on 700 MHz spectrum bands. AT&T established a separate band class that supports its own LTE devices, citing potential interference issues with adjacent broadcast television channels, however the regional carriers claim such interference is not a threat and AT&T's move serves instead to exclude the smaller players from the market.
The regional carriers cite their own study that is said to have found no evidence of interference between TV broadcasts on channel 51 and the Lower B- and C-block spectrum utilized by AT&T. The dispute essentially centers around devices, as handset makers have less incentive to make phones compatible with the smaller carriers' band class for Lower A-block spectrum. Conversely, devices built for Lower A-block spectrum band class will not automatically be compatible with the band class used by AT&T's LTE network for nationwide roaming.
In a statement quoted by CNET, an AT&T spokesman claims the report "is little more than a dressed-up version of a study previously filed and refuted" and "proves little more than 'garbage in' will produce 'garbage out.'"
"The study submitted by Vulcan, which it touts as a 'real world' study, does not replicate real world experiences, is limited in scope, and suffers from numerous defects, all of which undermine its credibility," AT&T wrote late last year in a letter to the FCC.
The regional carriers have acknowledged interference issues between the Lower A block and television broadcasts on channel 51, though they argue that the interference can be resolved and only affects carriers that use the Lower A block. AT&T has disagreed, claiming that interference problems potentially affect devices that utilize the Lower B and C blocks.