C Spire Wireless is pouring an additional $10 million into its network to harden its CDMA infrastructure ahead of its planned LTE launch.

The cash will be used to expand C Spire’s CDMA EVDO coverage in 61 cities and 65 counties.

The investment comes on top of the $90 million network expansion the company announced last month as part of its LTE prep.

When construction is complete, C Spire’s EVDO network will cover nearly 4.7 million consumers and businesses.

“Wireless devices are only as good as the network on which they work, which is why we’re aggressively expanding our advanced mobile broadband coverage,” C Spire COO Kevin Hankins said.

C Spire has not announced a specific launch date for its LTE network but said its first LTE smartphones would hit stores by the end of the year. The service will eventually cover its entire 700 MHz footprint, including areas in Columbus, Ga., Chattanooga, Tenn., Knoxville, Tenn. and Jackson, Miss.

The planned LTE launch is part of C Spire’s increasingly aggressive moves to take on its larger Tier 1 competitors.

The regional operator has steadily increased its line of high-end smartphones over the past year and announced last week it would begin selling the iPhone 4S, making it the first-ever Tier 2 carrier to land the hugely popular device. C Spire’s LTE launch will allow it to offer services comparable to its larger competitors, though interoperability problems with its 700 MHz holdings could restrict the network’s national coverage by limiting LTE roaming deals with AT&T and Verizon Wireless.