I have got the same problem as all of you. iPad2 3G with at&t as carrier and I upgraded to iOS 8.0.2 and now I'm constantly loosing my cellular data 3G connection... I have tried everything mentioned in this support group, but it doesn't solve the problem..... The only thing which works, is to power off my device and then it connects to at&t 3G netowrk again, - for a while, until I close the cover..... Not good enough at all.
I'm now so dissatisfied with apple and all kind of issues which never works with new updates etc. that I seriously consider to drop iPad and iPhone and go to Android and by a Samsung phone instead of a iPhone 6. I might consider buiyng a Windows Surface instead of a new iPad....
apple must do better in the future and Tim Cook and his keynotes only stating only how good apple is.....sounds somehow quite hollow..... and very predictable and too boring...... there is no exitement any longer... Come on apple, - you can do better.....