T-Mobile US is helping its low-cost MetroPCS brand double its market coverage with 15 new markets unveiled Thursday, most with 4G LTE connectivity.

This is the first move by T-Mobile to extend its newly acquired company beyond its original 15 city coverage base. The new markets also bring MetroPCS into many of the towns and cities covered by its major rival Leap Wireless. (See AT&T's Leap Bid: Stickin' It to T-Mobile?)

The expansion should allow MetroPCS users -- as they upgrade handsets -- to connect to T-Mobile's 3G HSPA+ and 4G LTE networks. "MetroPCS customers will experience speeds on average of seven times faster than the company's previous markets," says T-Mobile in a statement.

As you can see from the list below, all but three of the markets fall under T-Mobile's current 116-market LTE footprint:

Here's how the different U.S. operators stack up with 4G LTE deployments right now:



— Dan Jones, Site Editor, Light Reading Mobile