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Apple To Issue a 'Fix' For iPhone 4 Reception Perception
Lisandro and several other readers let us know that Apple has just released a statement addressing the signal issues a lot of users are having with their iPhone 4. They claim to have discovered the cause for the drop in bars, which is "both simple and surprising" — a wrong formula used to calculate how many bars are displayed for a given signal strength. "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. ... 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. ... We will issue a free software update within a few weeks that incorporates the corrected formula. Since this mistake has been present since the original iPhone, this software update will also be available for the iPhone 3GS and iPhone 3G." Wired notes that there is still a signal drop when the iPhone 4 is gripped in particular ways.
There's a serious analysis here, with some extra commentary by OS News here.
With digital phones, it's not necessarily signal strength (cell phone parlance = RSSI, Received Signal Strength Indication) you want to display. You want to include some measure of the signal/noise ratio, since that is a better indicator of a phone's ability to communicate.
And, in fact, that's what most cell phones do. For CDMA, it's usually some combination of Ec/I0 with signal strength, and for GSM it's some combo of reciprocal bit error rate combined with signal strength. Often time averaged and perhaps peak reading. So it's not just a simple "x dB RSSI = y bars" calculation. The combined metric is called SQE (Signal Quality Estimation).
"National Security is the chief cause of national insecurity." - Celine's First Law
Anandtech posted a review of the iPhone 4 the other day and they have a break down of the signal strength in dBm compared to how many bars are displayed. The specific page is here.
Basically it looks like there is a huge range for what is considered five bars, and a small range for the remaining four bars.
It's Defective by Design (TM)
For once, Apple copied Microsoft.
Check the consumer protection legislation in your area. It probably has something along the lines of products needing to be fit for the purpose for which they were purchased for a reasonable length of time, taking into account the price paid.
There are two types of warranties: Legal and Conventional.
Conventional Warranty (limit your rights): We warrant foo for 1 year (no warranty on batteries, screens, keyboards, accessories, etc).
Legal Warranty: Fitness for purpose for which it was purchased, taking into account price paid, etc. In other words, you paid $3k for that big-screen tv and it croaked 1 day after your conventional 1-year warranty expired? You can still use the legal warranty via small claims court. They can't hide behind the limitations of the conventional warranty - the conventional warranty is in addition to the legal warranty (which makes extended warranties stupid purchases).
Yes and no. The issue had to do with the scale used. From AppleInsider:
"Apple's iOS allots nearly 40 percent of reception levels to five bars, from -51 dB to -91 dB. But the distance from four bars to one bar of reception is much less, from -91 dB to -113 dB."
Unless you live under a rock, or have never cracked open ANY cell phone manual, you would know that they all recommend avoiding the lower left side where the antenna is located. The problem with Apple's configuration is that they used 5 bars for -51 to -91 db, which in itself is fine, since any call with those signal strengths would be very stable.
The problem has to do with dropping signal strength when you cover the antenna. Although you couldn't cause any phone to lose 63 db from grabbing it, getting a 20 db drop in signal strength isn't all that uncommon. If someone was in the weaker 5 bar range (say -90 db), which is still a decent signal, the phone would display 5 bars. When you covered the antenna, you could potentially get a 20 db drop, bringing you down to -110 db, which is a very poor signal. It gave the impression that someone went from 5 bars to no bars, or even no service (no service being very possible with -110 db).
There are no standards defining what dB is represented by the number of bars. It is totally up to the hardware manufacturer. As to whether or not this was a mistake, who can say? The haters will claim it's a marketing ploy, the lovers will claim it's a fair way to rate the signal. I'll probably fall in between.
What this fix will do is better represent the number of bars by signal strength in a more linear fashion, so that -90 might only be three or two bars, and covering the antenna would drop you to 1 or no bars. Although any phone might make a call at 1 bar, you should also expect that you might drop it with such a poor signal.
Frankly, I think most of the posts in these and other forums are full of 'noise' from people who hate Apple, from Droid fans, to people who just dislike them for their closed systems. It's an ideal way for them to take shots by spreading FUD and making the issue appear far worse than it actually is. Unfortunately, it also makes it much more difficult for people to judge the scope of the problem, which in itself is a win for Droid from a marketing perspective. I do know that I haven't dropped a single call on the iP4 regardless of the bar display. I suspect most fall into the same category. Reviews of the phone also back up the same. Dropped calls have actually been reduced under the iP4, regardless of the number of bars displayed. Anandtech actually has a nice write up and some more thorough testing of signal strength. What they found is that the exposed antenna's do make the iPhone 4 more susceptible to interference, but not so much that it would affect people with decent signal strength. It actually performs better than a droid for signal loss when it's in a cover:
http://www.anandtech.com/show/3794/the-iphone-4-review/2