The U.S. wireless industry is maturing and consolidating. LTE is pervasive, smartphones are ubiquitous and the industry is already looking ahead to 5G networks. But there is still a great deal of innovation occurring. Over the years, FierceWireless' Fierce 15 winners have symbolized that innovation, and this year's list is no exception. To see the 15 companies selected by FierceWireless this year, click here.