[Brian]

If you guys are seeing the issue I linked to above, switching to Airplane mode would prevent the WiFi connection from by removing the option for the phone to switch to the cellular radio.

iOS will automatically switch off the WiFi radio a few seconds after the phone goes to sleep, and transfer the remaining data over the cell phone radio instead.

Does the WiFi connection always drop after the phone goes to sleep? If you use settings on the phone to prevent the phone from going to sleep, does the problem still occur?