The new network may go live before the official launch dates in those cities, and subscribers with LTE-capable devices will be free to use the network as soon as it becomes available, Sprint said.

The timing of Sprint's announcement two days before the expected launch of Apple's iPhone 5 probably is not coincidental. The iPhone 5 is expected to have LTE, and as it launches, Sprint's major rivals will have that technology up and running in far more markets. Sprint's LTE service is already available in 19 metropolitan areas, including Atlanta, Baltimore, Dallas-Fort Worth, Houston, Kansas City, Missouri/Kansas City, Kansas, San Antonio, and some communities surrounding those cities.

Sprint's list of major upcoming LTE launches also included Charlotte, N.C., Miami, New Orleans, Philadelphia, and Washington, D.C.

Sprint already offers 4G service over partner Clearwire's WiMax network but is now building out LTE, which has become the telecommunications industry's standard technology for 4G. LTE's broader deployment, which already spans 100 carriers in 49 countries, according to a statement by the industry group 4G Americas on Monday, will allow Sprint to offer more devices and evolve toward faster versions in the future. Clearwire is also that Sprint will use to boost its capacity.

Sprint is deploying LTE as part of a total infrastructure rebuild called , which also includes upgrades to its 3G EV-DO network. Those upgrades boost signal strength and in-building coverage and reduce dropped calls, and they have already been made available in Baltimore, Boston and Washington, D.C., according to Sprint. The carrier expects to finish Network Vision by the end of next year.