Android vs. iPhone 4 Signal Strength Bars Comparison 253
thisisauniqueid writes "In light of the clamor over the iPhone 4 Grip of Death, AnandTech recently reverse-engineered the phone's signal-strength-to-bars mapping. Because Android is open source, we can determine the corresponding mapping for Android in combination with the 3GPP spec referenced in the source, allowing the signal-strength-to-bars mapping for both Android and the iPhone 4 to be plotted on the same axes. This shows that the iPhone 4 consistently reports a higher percentage signal strength (as defined by the fraction of bars lit) than Android GSM devices at the same signal strength."
not a surprise (Score:5, Interesting)
my wife's iphone constantly reports 3-4 bars and 3g in places where my motorola milestone reports 1 or no signal. it's not until she goes to make a call that -- oops! no coverage.
is anyone surprised? (Score:3, Interesting)
Re:noise floor? (Score:4, Interesting)
I think part of the issue is dB ranges of 0-~100 = 4-5 bars. dB Ranges 100-113 = zero-3 bars. You don't enter the '3' bar range until you're already on a weak signal, and can 'death grip' your phone to death. The article reported a max of ~24 dB signal drop from poor holding. From the looks you don't have to hold it too improperly to suddenly go 3 bars->disconnect.
This becomes an issue since people check their reception.. okay, 2-3 bars, im good... Then go make a call, or hold their phone to their head, and boom, 15dB difference, bye call.
The idea of "showing more bars to make users more comfortable" (or 'showing more bars to make people who think bars are standardized across phones think ours are better)... backfires when your 'bar' range doesn't properly tell people how close to disconnect they are and is 'mysteriously' goes from 3 bars to 0 -- like some people report.
because most people don't understand decibels? (Score:3, Interesting)
How about phones just print the dB signal loss and be done with it? A number should be far easier for someone to tell about signal strength than guessing by 0-5 bars.
Because 90% of the population has no fucking clue what decibels are? A logarithmic scale is a recipe for disaster in the consumer marketplace.
Actually, I think the unit in question is decibel milliwatts: http://en.wikipedia.org/wiki/DBm [wikipedia.org]
What does OSS have to do with it? (Score:4, Interesting)
Seriously?
You're comparing the iPhone using some physical technique to infer the signal level to bar mapping, taking into account all the variables of the phone hardware ...
And on Android you're just looking at the source ... not even the phone itself ...
And this is supposed to be some sort of comparison? Whats next? Submarine A goes 25 knots submerged, Space Shuttle X launches into space at 36k knots. Which one will get you to BurgerKing first?
When you compare things using completely unrelated ways of gathering your input data you find that your results are ALWAYS wrong, even if you can't see it or they agree/disagree with what you thought.
OS 2.1 (Score:5, Interesting)
After I got my iPhone 3G the very next software update included a change to the "bar algorithm" that was marketed as "improving user understanding of the signal meter" or somesuch. It was in response to user complaints of low signal strength, and somehow (miraculously) the reception improved... more bars.
So they're rolling back this change?
MJC
Re:Summarising... (Score:3, Interesting)
"Apple buyers don't take any notice of negative publicity for Apple products."
Actually, some buyers do. Not the hardcore fanboy types, but my gf's parents saw a segment on the local news about the iphone 4 problems and have decided to look at Android phones rather than blindly upgrading their current iThings to the latest model. They may still get an Apple phone, but they would not have even considered alternatives if it weren't for the issues.
I was surprised that there was any general media coverage of the problems with the iPhone 4. Between this and all the coverage of the goof up with the wireless connection at the announcement, they haven't been looking good in the mainstream news. I don't know if this will have any noticeable effect on sales, or if there is any way to know anyway.
Re:noise floor? (Score:5, Interesting)
You're sort of right.
-174dBm/sqrt(Hz) is the minimum that you can achieve at "noise room temperature" (290 Kelvin), because that is the spectral density of noise in the RF region that a black body will emit. But every component from the antenna, antenna switch, low noise amplifier, downconverters, filters, more amplifiers, and ADC's will add a certain amount of noise to degrade the signal further. This can be discussed as noise factor, noise figure, noise temperature, and so on, but those are all also equivalent to having an increased noise floor at the signal reaching the antenna, and by converting to input referred noise floor, the minimum detectable signal is often defined as the point where the signal power equals the input referred noise power.
This will definitely NOT be the same for all phones.
A very good cryogenic low noise amplifier like astronomers use for very sensitive radio telescopes might have a noise temperature of 5 Kelvin, corresponding to an addition of -191.5dBm/root(Hz) noise power at the input. However the low noise amplifier in a cell phone probably has a noise temperature around 75 Kelvin (1dB noise figure at room temp), adding -179.7dBm/root(Hz) noise power. The first amplifier would be able to detect a signal 15 times smaller because of its superior noise performance. In fairness though it probably costs about a thousand times more...
Re:Smelly code! (Score:4, Interesting)
Code says 'Copyright (C) 2008 The Android Open Source Project', complain to them. Or better yet, fix their code. Isn't that the point of open source?
Re:not a surprise (Score:1, Interesting)
I just recently switched from an iPhone 3G to an Incredible, and, granted, they are different networks, but this issue became apparent to me. In my apartment, my incredible typically only shows 1 or 2 bars but I always get a consistent signal. My iPhone used to show 5 bars but fail to make and drop calls constantly.
Boy am I glad I finally got rid of that thing...