Picocell is described
here. Existing technology to connect any and all cell phone frequencies, via a satellite, to ground networks. It's like putting a cell tower in the airplane.
Load Toad, who's talking about conversations? You are the first to mention it.
In any case inflight use of cell phones is the reality now. Many non-US airlines have already deployed it. And you know what? Because they charge $2+ a minute, hardly anybody ever uses it. Much higher use of texting and surfing.
I remember when almost every airplane had a phone in the seat back. Airfone or something like that. Also expensive to use, so they rarely were. I did once when my SR flight was diverted from LHR to LGW, due to the T1 Burger King fire. Airlines pulled them out due lack of use.