AT&T plans to expand its third-generation (3G) wireless broadband service to more than 80 additional cities throughout 2008.

That expansion would bring AT&T's 3G coverage to nearly 350 major US markets, including all 100 of the largest cities, the carrier said in a statement. The initiative will require AT&T to build more than 1,500 additional mobile locations nationwide.

The carrier also said it will complete its High Speed Uplink Packet Access-enabled network by midyear, allowing laptops so-equipped to receive data via HSUPA to more quickly send large files and business applications wirelessly.

AT&T's Web site describes its current 3G network as a Universal Mobile Telecommunications System/High Speed Downlink Packet Access (UMTS/HSDPA) or Broadband Connect network, offering speeds of 400Kbit/sec. to 700Kbit/sec. But in Wednesday's announcement, AT&T said it is now delivering downlink speeds of 600Kbit/sec. to 1,400Kbit/sec. and uplink speeds of 500Kbit/sec. to 800Kbit/sec.

Such network speed claims are confusing and somewhat academic, said Jack Gold, an analyst at J. Gold Associates. That's because they do not reflect a network shared by many people, which can slow down data-transfer speeds.

AT&T has been widely criticized by iPhone users who must rely on the carrier's Enhanced Data Rates for GSM Evolution (EDGE) network, which is much slower than UMTS/HSDPA, with download speeds of 70Kbit/sec. to 135Kbit/sec.

Gold noted that users might be constrained by the slowest network technology when making a voice or data call, simply because network routing technology will choose the most convenient pathway.

In general, AT&T's current network offerings are "a little bit slower" than Verizon Wireless' EVDO-Rev. A network, which is used by laptops equipped with broadband data cards, Gold said. AT&T faces competition from Verizon and Sprint Nextel Corp. for mobile workers interested in using broadband laptop cards, although AT&T has begun selling some HSUPA-capable cards.

Phillip Redman, an analyst at Gartner, said that AT&T's announcement Wednesday might be intended to support sales of more laptop cards. He also said it signals that AT&T is hoping to support more wireless devices, including a future version of the iPhone. "They don't want iPhone users to use WiFi against mobile," he said.

In addition, he said that AT&T realized the biggest complaint of wireless users is the need for more coverage.

Craig Mathias, an analyst at The Farpoint Group, said the expansion is "what you'd expect, so I wouldn't read too much into it."

AT&T could not be reached for comment on its plans. The network expansion is likely to be welcome news for customers who need faster access in more places, Gold said. "It's a natural progression for AT&T, but the really big growth will be in three to five years when they deploy LTE [Long Term Evolution]," he said.