Hi guys , i am from India and i am suffering from the same problem . Like everyone else i've been using the phone over two years and i love it. I have taken the cell to an expert that did some work with same sim and the cell worked. Problem arises when i reached home and it started to show the same problem again but it catches in a good signal zone.
Don't know if it is due to network I.C. or something else but it sure has something to do with the software