I wish it was possible to do direct phone to phone data communication, a bit like CB but for data. Of course the range would be limited because of phone batteries, but at least you would not require a large, expensive network of antennas. I have asked SDR folks about it but they're not convinced. Just imagine not having to rely on network operators for tiny amounts of data. Only a phone would be required, without pai…
The limiting factor wouldn't just be batteries. The antenna size and location (you aren't up on a tower) is a tremendous limiting factor.
As long as it would be possible to send very small amounts of data, it would still be quite a big achievement.