Why the iPhone 4 Software Update May Result in Fewer Dropped Calls

The backlash to Apple’s “Letter Regarding iPhone 4”–in which the company addresses dramatic drops in the number of bars displayed on the device when a small sliver separating the external antenna is bridged by a finger or hand–has been swift. Rebuttal posts to Apple’s Discussion boards include:

• BryC: “This is whats called the Jedi Mind trick, to end all mind tricks. There is…no iPhone issue.”
• Booyah24: “I think this is a Apple’s attempt to calm down the masses by finally acknowledging that there is a problem, but they are not admitting that its a hardware design flaw. A software patch will not make this go away and I feel sorry for anyone thats hoping it will.”
• vidguy7: “And displaying the ‘correct’ number of bars does NADA for issues where you can’t connect, can’t hold a call or can’t access websites when the person sitting right next to you with a 3GS has no issues.”

However, although Apple’s letter does not explicitly mention that the forthcoming software update will result in any reduction to dropped calls/connections, circumstantial evidence suggests that the software update may in fact deliver such improvements for the following reasons:

3G versus EDGE. The iPhone 4 automatically switches to EDGE from 3G when the 3G signal falls below a certain threshold. One hypothesis holds that the new signal recognition algorithm included in the iPhone 4 software update will more accurately recognize when a 3G signal is untenable, and more aggressively switch to EDGE before calls are engaged. Because calls drop when the switch from 3G to EDGE is made and EDGE coverage is significantly more vast than that of 3G, this change may result in a real-world reduction in dropped calls.

As noted in our list of fixes for the reception issue, several users have experienced faster throughput via EDGE than 3G when this issue manifests.

Bad calibration. Some RF antenna engineers suggest that faulty calibration of the iPhone’s signal recognition mechanism may result in unnecessarily dropped calls. In other words, the iPhone 4 may be incorrectly triggering call drops when a viable signal exists. The recalibration included with the forthcoming iOS software update may improve this situation.

A software signal boost. Previous iPhone software updates have reportedly boosted signal strength by increasing power to the antenna.  The forthcoming iOS software update may include a similar change, which would likely result in a slight degradation of battery life, but improved cell reception and signal strength. Because the loss-of-reception issue is much more likely to occur in areas where signal is already weak, such a change could result in more reliable overall connectivity.