Once in a while you find folk with cell phone booster systems but indoors the signal is indeed less and may not trip your iphone's trigger. My home suffers from similar Sprint issues so I have to consider other carriers.
I have an iphone 3. No problem til husband got a 4 two months ago. Since day one, we were no longer able to recieve a call at home. Can txt, email, make call. All incoming calls go to VM. Outside home, all calls are received. We have an airwave. Apple did set up check and said all is well. Sprint store and phone techs have not been able to diagnose after multiple visits/calls. Any ideas?