AT&T, now the nation's second largest cellular network after Verizon, today announced plans to upgrade its 3G networks nationwide.  The company provides service to over 78.2 million customers in the U.S.

Most of the company's network is currently based on the High Speed Packet Access (HSPA) technology, built upon a 3G UMTS network.  Currently, AT&T uses HSPA speeds of 1.8 or 3.6 Mbit/s (downlink and uplink), but with the upgrade it will be capable of 7.2 Mbit/s (uplink and downlink).

Starting in 2010, the company also plans on rolling out 4G LTE trial deployments.  By 2011 to 2012, it expects this technology to be standard.  In the meantime, AT&T plans to provide a boost to its mobile broadband offerings by doubling the wireless spectrum it dedicates to 3G in most metropolitan areas.  It also plans on adding thousands of new cell site backhaul connections to help support the broadband network.

The investments will come as part of the $17B to $18B USD that the company plans on spending on new capital development in 2009.

AT&T has seen its subscriber numbers soar with the addition of the chic Apple iPhone to its fold.  However, it has also suffered from service problems, due to, among other factors, the increased use of mobile video from smartphones, chiefly the iPhone.  With a new iPhone reportedly set to launch this summer, it’s hoping to have its network rise to the occasion and be able to provide enough bandwidth to adequately support new subscribers.