Wireless carrier AT&T has announced their new 4G LTE data network is now available in 11 new markets, bringing the total to 26. Cities now with 4G access include New York, San Francisco, Los Angeles, Raleigh, and Orlando. Markets that already had the network include Chicago, Houston, Indianapolis, Las Vegas, Washington, D.C., and Puerto Rico.

AT&T’s 4G network is dual-layer, meaning that it uses both LTE and HSPA+ technology. This makes it compatible with a larger number of phones and prevents users from experiencing a sudden drop in data speeds when transitioning out of an LTE-covered area. This also gives AT&T a competitive advantage over Verizon regarding the iPhone 4S. The iPhone 4S is HSPA+ compatible, but not LTE compatible, which means that Verizon iPhone users have no access to their carrier’s 4G network. AT&T iPhone customers, however, will get at least a partial speed boost from AT&T’s new network.

According to AT&T’s press release, they expect deployment of their 4G network to continue throughout 2012, and be mostly done by the end of 2013.

Are you in one of AT&T’s new 4G markets? Tell us about it in the comments.

[Source: AT&T Press Release]