U.S. Cellular is adding to its 700 MHz reserves with spectrum purchases in North Carolina and Nebraska.

The regional operator has filed two applications with the FCC to buy three 700 MHz licenses in North Carolina from Cavalier Wireless and one application to buy two 700 MHz licenses in Nebraska from USA Communications.

The lower A block and B block spectrum will be used for "innovative wireless services... and will allow USCC to improve and enhance its voice and data service offerings in those markets," according to documents posted Friday to the FCC's website.

U.S. Cellular is using 700 MHz spectrum for its LTE network, which will launch in six states next month, including North Carolina. The regional operator's limited spectrum holdings prompted it to partner with King Street Wireless to run its LTE network in several markets.

The FCC is giving the public until Feb.24 to file petitions to block the deal, with replies to those pleadings due March 5. Final comments must be submitted by March 12.

Once the transaction is approved, U.S. Cellular will hold 49 MHz of spectrum below the 1 GHz band in six North Carolina cellular market areas, adding to the spectrum it can use for LTE. In Nebraska, U.S. Cellular will hold 49-61 MHz of spectrum below the 1 GHz band in eight counties post-transaction.

U.S. Cellular's debut LTE launch will cover about a quarter of its customers in Iowa, Wisconsin, Maine, North Carolina, Texas and Oklahoma. The Samsung Galaxy Tab tablet will be its first LTE device, followed by the Galaxy S Aviator smartphone.

The network will help the regional operator keep pace with larger Tier 1 competitors AT&T and Verizon Wireless, which already have substantial LTE footprints. Ongoing customer losses shrunk U.S. Cellular's subscriber base to 5.93 million at the end of last September. The company has not said when it will announce its fourth-quarter results.