Ask telecom officials why Atlanta is a heavyweight in the wireless industry, and you get a pretty simple answer.

"Really, it relates to who's here," said Tom Clear, chief commercial officer of SpinVox, a startup wireless-applications company that has headquarters in Atlanta and London.

The city is home to AT&T Mobility, the largest mobile-phone carrier in the United States, and the Southeast headquarters for Verizon Wireless and Sprint-Nextel. A number of startups, including Spinvox and Cbeyond, a small business telecom provider that was recently named one of the state's top performing companies, also are based in the metro area.

Those reasons are fodder for the metro Atlanta Chamber of Commerce to call the city the "wireless capital of the United States." Forbes also ranked Atlanta at the top of its "most wired cities" list for the past two years, largely because of the number of people who own cellphones, BlackBerries, wireless air cards or a combination of the three.

"People (here) are buying multiple devices: a cellphone, an e-mail device like a BlackBerry and an air card for their computer," said Jeff Mango, president of Verizon Wireless' Georgia-Alabama region.

Tuesday marks an additional milestone industry experts say: The GSM Association, widely considered among telecom types as the big dog of the wireless world, brings its annual Mobile Innovation Marketplace to the Omni Hotel downtown.

GSM, of global system for mobile communications, is the foremost international standard for digital cellphones and has widely been used in Europe and Asia for years. Some major U.S carriers, including AT&T, use the standard.

The association represents 750 mobile-phone companies in 216 countries and has offices in London, Hong Kong and Barcelona, Spain. In October, the association chose Atlanta for its U.S. headquarters and opened a 40-person office at the Northpark Town Center.

"GSMA coming to Atlanta is very important. This is a worldwide organization that has so much clout you wouldn't believe it," said Scott Shamp, director of the New Media Institute at the University of Georgia. "We're going to see much more international influence here."

Jeff Kagan, a longtime telecom analyst who has lived in Atlanta for 25 years, said GSMA considers the metro area a pacesetter in terms of technology use. "Here we are in Atlanta enjoying many of these new technologies that many other people in the country are still looking for," he said.

The two-day mobile innovation conference is a coming-out party for the association's new U.S. office, said Bill Gajda, GSMA's chief commercial officer. He said it was attracted to Atlanta because of the role the city's media and entertainment business play as well as having AT&T and others here.

"AT&T is a large part of a global ecosystem," Gajda said. "It connects to more than 100 operators around the world."

Maury Mogul, president and co-founder of the Atlanta-based Wireless Technology Forum, agrees, saying international vendors will have a high profile at the conference. Armed with new music, movie, photo and other technologies, vendors from Spain, Italy, China and elsewhere are hungry to partner with AT&T, Verizon and others to reach more customers, he said.

"The fact they are bringing in hot new technologies and showing them in Atlanta, the U.S. carriers have to take notice," Mogul said. "A lot of these technologies have been successful, and they look at the U.S. as the Holy Grail."