Leap Wireless International, the parent company of prepaid carrier Cricket Communications, says COO Al Moschner will retire by the end of the year.

Leap has struggled to turn a profit off its prepaid subsidiary and control its high churn rate, which hit 5 percent in the most recent quarter. The company announced a new strategy in August that included a five-year roaming agreement with Sprint and nationwide 3G coverage.

“For several quarters, we have been laying the foundation for a new phase of growth and we now have all of the pieces in place that will enable Cricket to scale into a national carrier,” Moschner said in a statement. “As we move into the implementation phase of our strategy, it’s time for new operational leadership that is committed to executing our strategy for many years to come.”

Moschner first joined Leap in 2004 and was appointed COO in July 2008. He plans to continue working with Cricket in a consulting role following his retirement, which is slated for Dec. 31, but could come earlier if a successor is appointed before the end of the year.

Leap said it is in the “latter stages” of a search for Moschner’s successor but did not release further details about when a new COO would be appointed.

In a separate announcement, Cricket Communications said it was buying out its remaining stake in Denali Spectrum. The carrier already owns 82.5 percent of the company. The purchase will give Cricket control of Denali’s Chicago and southern Wisconsin markets.

In a separate deal, Denali is selling its non-operating wireless licenses and spectrum lease to Savary Island Wireless and Ring Island Wireless. Savary will assume $211.6 million of Denali’s debt to Cricket under the terms of the deal.