Before the release of Apple's iPhone last year, AT&T upgraded its EDGE data network.

With Steve Jobs expected to unveil the next-generation iPhone in a few days at Apple's Worldwide Developers Conference, it may not be surprising that AT&T has upgraded its high-speed mobile broadband network.

The company said its 3G network can now reach speeds of 700 Kbps to 1.7 Mbps on the downlink and 500 Kbps to 1.2 Mbps while uploading. This is a 20% increase from download speeds of 600 Kbps to 1.4 Mbps and upload speeds of 500 and 800 Kbps.

This move could potentially draw mobile professionals from rivals Verizon Wireless and Sprint Nextel. For its mobile broadband networks, Verizon and Sprint utilize a CDMA-based technology called EV-DO. Those 3G networks generally get download speeds of between 500 and 800 Kbps and upload speeds of 500 to 800 Kbps.

AT&T utilizes High Speed Packet Access for its 3G network, and the increased speeds come as a result of deployment of faster uploading and downloading technologies, known as HSUPA and HSDPA. The faster 3G service will be available to customers with HSPA-enabled handsets and laptops, including any laptop with a Laptop Connect wireless modem.

Currently the company's 3G network is available in more than 275 major U.S. markets. By year's end, the company said it will expand to nearly 350 metropolitan areas.

AT&T said it has invested more than $20 billion since 2005 in improving its 3G network. AT&T, along with Verizon and its new acquisition, Alltel, plans to adopt Long Term Evolution (LTE) technology for the next generation of mobile broadband access.