But Sprint hasn't decided what it actually will do with its new technology and, in particular, whether it will use it for voice, Krueck said.

"We're strategizing now about what the business model would look like for giving access to various types of applications over the IP network," Krueck said. "With [VOIP], we could block it, accept it or establish a business model with vendors like [VOIP provider] Vonage where, if you want to mobilize VOIP, we could charge for the relationship. Those discussions haven't happened yet, but that's an option. Any way you look at it, wireless companies that carry that traffic will have to be compensating, or we'll go out of business."

Krueck stressed that Sprint and the other cellular carriers didn't spend billions to build out their networks just to have their revenue taken away by VOIP over other types of wireless networks.

"It doesn't make sense to move our 50 million customers off an existing infrastructure," Krueck said. "Still, over time we might cap that network and grow the other [IP-based] network."

Even a potential competitor like TowerStream is still trying to figure out a sensible business plan, TowerStream's Thompson acknowledged.