DNT, LLC, Plaintiff/Counterclaimant-Appellant, v. SPRINT SPECTRUM, LP and Nextel Operations, Inc., Defendants-Appellees, and Cellco Partnership (doing business as Verizon Wireless) and Alltel Communications, LLC, Defendants-Appellees, and T-Mobile USA, Inc., Defendant-Appellee, and United States Cellular Corporation, Defendant-Appellee, and Novatel Wireless, Inc., Counterclaim Defendant-Appellee