As part of its wider 4G LTE roll out, US operator Sprint announced today that it has begun building its network infrastructure in more than 100 new cities within its existing 3G areas, with around fifteen of its most popular areas set to see upgraded connectivity in the coming months.

Sprint says that some of the major city areas that will see 4G LTE first will be Boston, Charlotte, N.C., Chicago, Indianapolis, LA, Memphis, Miami, Nashville, New Orleans, New York, Philadelphia and Washington, D.C.

This adds to the 19 cities which it has already pushed its 4G services live, which includes a wide area of Georgia, Kansas City and some parts of Texas.

Sprint says that during its pre-launch phase, customers may be able to connect to the LTE networks before they officially launch. The company plans to expand its commercial availability of its 4G networks in the coming months, until it eventually hits the same footprint as its existing 3G networks.

When does the operator expect that to happen? “By the end of 2013, Sprint expects to have completed the nationwide build out of the all new 3G and 4G network,” the company says.

While it launches its 4G services, Sprint says it is committed to overhauling its 3G infrastructure to increase signal strength, build better coverage and reduce the number of dropped calls. Customers in Baltimore, Boston and Washington, D.C. will be among the first to experience these improvements.

[Image Credit: TheDarkThing]