Wireless carrier T-Mobile USA has performed more upgrades to its 3G network, enabling a wider range of people to benefit from the HSPA+ speeds it can offer.

Following the recent enhancements, T-Mobile offers HSPA+ to users in 55 markets in the United States, being able to offer coverage to over 100 million people, or a little more than 30 percent of the U.S. population.

“Today, T-Mobile USA, Inc. announced the continued expansion of its super-fast mobile broadband network to 100 million Americans in more than 55 major metropolitan areas,” the wireless carrier noted in a press release.

T-Mobile’s HSPA+ network was already available in a number of more than 45 markets in the US, delivering theoretical peak throughput speeds of 21Mbps.

The network was upgraded to HSPA+ in nine cities, including Boston, Mass.; Erie, Penn.; Fresno, Palm Springs and San Diego, Calif.; Miami, Fla.; Richmond, Va.; Spokane, Wash.; and Topeka, Kan.

“Our new network offers today’s available 4G speeds to more people than any other wireless network in the country and we’re not done yet,” Neville Ray, chief network officer for T-Mobile USA, commented on the launch.

Further more, the wireless carrier says that it expects to deliver HSPA+ coverage to more than 200 million people, while having in store more upgrades for the next year.

“We are now on pace to more than double our HSPA+ footprint – reaching more than 200 million people by this year – with plans to offer 42Mbps theoretical speeds in 2011,” Neville Ray continued.

In addition to making these network enhancements, the wireless carrier is readying the launch of the first smartphone that would pack HSPA+ connectivity, the T-Mobile G2.

There are no specific details available on the handsets availability at the moment, but there are great chances that the mobile phone would land before September is over, at least this is what some of the rumors on its suggested.