Extended Low Signal = No calls or data until restart.

I have noticed problem with my iPhone 3GS that has not been a problem until the past couple of days. At first I thought it was just a data network problem and then my phone just stopped making calls at all even though I would leave my home, where there is only about 1 bar of signal, to somewhere I have full to 4 bars and couldn't make calls or get on the data network.

I was able to get my iPhone to cooperate but I had to restart it twice. I am in the process of restoring it just to see if that will help with the problem. Any suggestions on where I should go from here if the restore doesn't work.

Thanks in advance.

The restore didn't seem to help the issue any. I have 3 bars of signal, sitting in the same place and I just attempted to call the phone and it never rang.

It looks like I will be upgrading the phone.