Monday, July 5, 2010

The grip of death: Apple's take and what the experts say

In the face of growing criticism from users about the grip of death, Apple has released a statement that says that all mobile phones suffer from a loss of sensitivity when the antenna part is covered, but that on the iPhone 4, the problem looks worse than it is because of the way the iPhone displays the number of bars.

"To start with, gripping almost any mobile phone in certain ways will reduce its reception by 1 or more bars. This is true of iPhone 4, iPhone 3GS, as well as many Droid, Nokia and RIM phones," notes the statement.

It notes that the dramatic drop in bars, however, is not because of a faulty antenna but because of a faulty algorithm that makes a weak signal look stronger than it should be.


"Upon investigation, we were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong," says the statement. "Our formula, in many instances, mistakenly displays 2 more bars than it should for a given signal strength. For example, we sometimes display 4 bars when we should be displaying as few as 2 bars. Users observing a drop of several bars when they grip their iPhone in a certain way are most likely in an area with very weak signal strength, but they don’t know it because we are erroneously displaying 4 or 5 bars. Their big drop in bars is because their high bars were never real in the first place."

According to Apple, this is why the drop in the number of bars looks so dramatic on the iPhone 4. A software update will be released that will correct the way the bars are displayed.

Is the iPhone 4 a better phone?

The software update will not improve reception; it will only improve the way the iPhone reports the signal strength. The software update will not change the iPhone 4 fundamentally. So the important question is really - how good is the iPhone 4 as a phone? Apple's statement notes: "... we continue to read articles and receive hundreds of emails from users saying that iPhone 4 reception is better than the iPhone 3GS. They are delighted. This matches our own experience and testing."

Anandtech's review, for one, says that the iPhone 4 has a better antenna than before. "From my day of testing, I've determined that the iPhone 4 performs much better than the 3GS in situations where signal is very low, at -113 dBm (1 bar). Previously, dropping this low all but guaranteed that calls would drop, fail to be placed, and data would no longer be transacted at all. I can honestly say that I've never held onto so many calls and data simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so it's readily apparent that the new baseband hardware is much more sensitive compared to what was in the 3GS. The difference is that reception is massively better on the iPhone 4 in actual use."

However, it does go on to point out that Apple's bumper will improve performance.

"With my bumper case on, I made it further into dead zones than ever before, and into marginal areas that would always drop calls without any problems at all. It's amazing really to experience the difference in sensitivity the iPhone 4 brings compared to the 3GS, and issues from holding the phone aside, reception is absolutely definitely improved. I felt like I was going places no iPhone had ever gone before. There's no doubt in my mind this iPhone gets the best cellular reception yet, even though measured signal is lower than the 3GS."

Spencer Webb, an antenna designer and the president of AntennaSys, says the issue is overblown. His initial reaction on using the iPhone 4 is that the phone is "not nearly as hypersensitive to "hand" effects as I was being led to believe from the media buzz." He says the latest iPhone seems to be "as sensitive to hand effects as the Primordial iPhone" and that electrical tape over the "band" does not help.

Webb also makes a point about the importance, or rather, the lack of importance of using bars as a way of measuring cellphone signal quality. "I've said it before, but now let me say it slightly differently: the only worthy metric for the quality of the cellphone is frequency of dropped calls when compared with other phones used in the same manner, over time. You cannot tell the difference between a "one-bar" conversation with your mother, and a "five-bar" conversation. (This is not be confused with having a conversation with your mother FROM a bar, which I don't recommend.) The only way to observe dropped calls is to use the phone for a statistically significant amount of time."

This echoes a point made in the Anandtech review that measuring signal strength is not a good way to report signal quality. Says the review: "That brings me to the way that signal quality should really be reported - Signal to Noise Ratio (SNR). SNR is essentially a measure of how much of the signal is compromised by noise or interference. It's readily apparent that because the iPhone 4 works almost perfectly fine at -113 dBm, it has much better sensitivity. The deciding factor for reporting the signal quality metric is then SNR, something Apple and other handset manufacturers will have to move to eventually instead of just power. In reality, reporting based on SNR makes a lot more sense, since I couldn't make calls drop driving around an entire day cupping the phone, despite being at -113 dBm (1 bar) most of the time."

(Ars Technica has a good piece from two years ago that discusses the disconnect between bars and cell signal.)

Speaking from personal experience with an iPhone 3GS running iOS4, I can certainly confirm that having four or five bars is no guarantee that your calls won't drop. While at Sim Lim Square the other day, I managed to have my calls drop repeatedly, even though I was merely standing in front of a shop. (So much so that the other person on the line asked me jokingly if I was using the iPhone 4.)

I'm not sure whether it's because of iOS4 or just overloaded cell networks but of late, I've certainly noticed numerous dropped calls even when I'm stationary in a location with allegedly good reception. Beyond mere gadget lust alone, if the iPhone 4 can provide fewer dropped calls, that's one more reason to upgrade (not that I really need a good reason...)

Note: To get the latest about the iPhone and iPad in Singapore, follow @imerlion on Twitter!
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1 comment:

Guan said...

Nice post. Folks like to stir up stuff when they can.
I have noticed as of 3-4 weeks ago, that my phone would lose all bars and a 'Network Cellular Reception has been lost signal' would come on. In some cases, a simple re-swipe of the 'Enable 3G' button solved in, in couple isolated instances, other parties could not call through to me. Dunno if you heard of anyone who'd encountered this before. These message appeared before my upgrade to iOS4, and thereafter, so can't be an OS thing.