AT&T will expand its trial of broadband wireless access to Atlanta in the fourth quarter, using pre-certified WiMAX equipment, AT&T officials said. After launching a small initial test market in Middleton, N.J., near company facilities, AT&T has been encouraged by customer uptake and feedback and will launch a four-tower commercial trial network in downtown and suburban Atlanta in order to guage the technical trials, said Sanford Brown, AT&T vice president of access product management.

While the Middleton trial used pre-WiMAX proprietary gear from several vendors, the Atlanta trial will use the same equipment multiple WiMAX vendors have submitted for certification trials to the WiMAX Forum. While Brown doesn't expect the gear to be fully certified by the fourth quarter, he expects very little in the way of upgrades to turn the network into a fully compliant WiMAX network.

"This is all equipment built to be compliant with the WiMAX standards," Brown said. "We expect there won't be any big variations between what we're deploying now and the fully certified equipment."

AT&T, however, is not revealing which vendors' gear it is using in either trial, though Brown said that AT&T won't be tackling interoperability at this stage. He said the carrier would only pair off a vendor's base station with the same vendor's CPE gear. As for Spectrum, AT&T is eschewing the unlicensed bands for which most WiMAX gear is now being optimized, in favor of experimental frequencies on loan from the FCC. Brown said the reason is simple. AT&T wants to avoid unlicensed spectrum if possible since most of its customers are businesses and enterprises.

Unlike its fellow IXCs AT&T doesn't own nationwide sub 10 GHz spectrum over which to deploy a broadband wireless network. If it were to go ahead with a commercial launch of a WiMAX network it would need to acquire licenses or adopt unlicensed.

Last week BellSouth announced it would launch broadband wireless trials in nearby Athens, Ga., and would add two more markets to its growing network by the end of the year.