iOS 7 has a new feature that isn't as sexy as the new camera or Touch ID but it is still pretty neat. It's called Multipath TCP.
Multipath TCP allows users to maintain connectivity between WiFi and cell signals so when the mobile warrior move from one network to another, say you're at a coffee shop and you walked out into the parking and loses the cafe's WiFi signal, iOS 7 knows to pick right off using your LTE or whatever cell signal you've got.
It works by staying connected to both networks at the same time. My question is then about what the battery life? It's great that there is no interruption but you have to think that there is always power being drawn when the cell antenna has to work in this fashion.
I lack the technical background to answer this, I do believe this is a fair question to ask.
Then comes my second question. Who gets this new ability? Any with iOS 7 installed? Apparently, that is the case. No new hardware is needed.