The most important input in our new wireless world is spectrum, or the invisible airwaves that are used to send and receive the radio signals that power wireless communications. For decades, slices of spectrum have been reserved for different uses, from television broadcasting to military radar. But today demands on our airwaves have grown. So the Federal Communications Commission has been working to clear these airwaves of old uses and auction them so they can be repurposed for new 5G service.