Leading US wireless carrier AT&T said Wednesday it would complete the roll-out of HSUPA technology on its 3G network by the end of June, which will boost possible upload speeds to 800 kilobits per second.

HSUPA will complement HSDPA, which has already reached all of the 275 markets currently served by AT&T's 3G network. The addition completes the company's deployment of HSPA technology, which will eventually make way for HSPA+ and at some point in the future, LTE.

With an HSPA network, customers will see a maximum of 1.4 Mbps download speeds and between 500 and 800 Kbps upload speeds. These are the same speeds promised by Verizon's EVDO Revision A 3G network.

HSPA+, or Evolved HSPA promises up to 42 Mbps downstream and 22 Mbps upstream -- although the actual transfer speeds seen by customers will be far less due to network overhead.

Eventually, AT&T along with Verizon and Alltel plan to migrate to LTE, a so-called 4G technology for wireless data. LTE, or Long Term Evolution, could pave the way for download speeds of up to 300 Mbps. However, the technology remains many years away and has competition from WiMAX, which is backed by Sprint and a new consortium including Google.

In the meantime, AT&T's network upgrade should give the company a much needed boost in the 3G space. The carrier previously lagged behind Verizon and Sprint in speed and coverage, and has invested $20 billion since 2005 to upgrade its infrastructure. AT&T expects its 3G network to be in almost 350 markets by the end of the year, which could surpass Verizon's coverage area.

Verizon is said to be preparing to roll out EVDO Revision B, which would boost download speeds with a software update to cellular towers and require new hardware purchased by customers, as did the upgrade from Rev 0 to Rev A.

The upgraded HSUPA network will require a laptop card that supports the technology, which AT&T began selling last October. All of the cards currently sold by AT&T are compatible with HSUPA.