Inside iPhone 3G Dropped Calls and How iPhone 2.0.2 Update Works

Submitted by lalit on August 28, 2008 - 5:55pm.

Few days back AT&T had send all iPhone 3G owners text message guiding them to update to the latest 2.0.2 software via iTunes. Many have speculated that Apple’s latest iPhone update is aimed at resolving the call drop problems. And even after the update has been released few users are still reporting the problem. RoughlyDrafted is now reporting more details via an AT&T source that explains the original issue and why some users didn’t notice any immediate impact after updating their devices.
According to the RoughlyDrafted’s source “In UMTS, power control is key to the mobile and network success. If the user equipment (UE) requires too much downlink power than the base station or Node B can run out of transmitter power and this is what was happening. As you get more UEs on the cell, the noise floor rises and the cell has to compensate by ramping up its power to the UEs”
The source continues, “If the UE power control algorithm is faulty then they will demand more power from the cell than is necessary and with multiple users this can cause the cell transmitter to run out of power. The net result is that some UEs will drop their call.”
The iPhone update 2.0.2 fixes the power control on the mobile and that’s why AT&T is sending the text messages. The source says, “ In a mixed environment where users are running 2.0, 2.0.1 and 2.0.2, the power control problems of 2.0 and 2.0.1 will affect the 2.0.2 users.” Hence, even after updating their iPhones some users are still having call drop problems.
The source says that he has seen dropped call graphs that correspond to the iPhone launch and when the 2.0.2 firmware was released. The graphs clearly show that 2.0.2 software has already started to make difference. So people, if you haven’t updated you iPhones do so as soon as possible, it will not only help your reception, but will affect others also.