United States Cellular Corporation (NYSE:USM) shares are trading higher on Friday after the company agreed to sell part of its retained spectrum licenses to Verizon Communications Inc. (NYSE:VZ) for $1.0 billion. In particular, the company agreed to sell 663 million MHz POPs of its Cellular (850 MHz) spectrum, along with 11 million MHz POPs of AWS and 19 million MHz POPs of PCS licenses, to Verizon. The purchase price will be paid in cash, with possible adjustments as outlined in the agreement. Telephone and Data Systems, Inc. (NYSE:TDS), as the 82% majority shareholder of US Cellular, has pro…