I'm not sure if anybody else has this problem but my iPhone 5 tends to drop the cellular connection when it's in standby for a prolonged amount of time (20 mins or so). This means I sometimes receive text messages 10 mins late when I open my phone. It's pretty frustrating because my iPhone 4 never had this problem. I'm contemplating going into the Apple store today to see what's up. Any suggestions? Or anyone else having this problem?