Why is my iPhone just randomly going into edge service?

It's Been happening recently. I have a 3gs iPhone, and even if I reset network settings, like 15 minutes later it will go back and do the samething. Has this been happening to anyone else? And right now as I type this message, my phone lost all service and went back to Edge service -_- what should I do?

Anonymous2010-06-06T19:58:24Z

It is probably getting bad reception for 3g. Try going outside, or call and complain to AT&T.