Allow FM radio stations to concurrently provide analog audio and digital WiFi like is already done in China.
Portable radio's with USB Wi-Fi jacks are common in China and should already exist here in the USA. Wi-Fi should already exist anywhere an FM radiuo station can be heard. This technological certainty would only require distributed towers like cell phones use to handle the back traffic.
Frequencies are no longer the limited quantities they once were. Why is the not obvious? Time displaced modulation of frequencies makes or will make carrier frequencies an almost unlimited resource that would still need to be regulated.
Curts J Neeley Jr commented
If light goes 186,000 miles per second, how far will it go in .000000000333333 seconds or during 1/3000000000 of a second? or one cycle of a 3G signal? This is slightly less than 4 - inches. How long is one cycle of a 20,000 Hz sound wave? ..00005 seconds. How many cycles of 3G fit inside one 20K cycle? What about .05 seconds or 20Hz? Roughly 150K to 1.5G respectively