Understanding cellular data networks on iPhone 3G is an interesting read on Apple’s website. It tries to answer a lot of the questions that user’s have been asking about those pesky ’signal strength’ bars on the top of the display, similar to ones at the top of this blog. It’s amusing how those innocent little bars are causing so much concern. Perception is everything.

I noticed it too. Put the 3G device alongside the 2G one and the bars look very different. Almost without exception, the 2G device shows ‘better’ signal strength than the 3G one. Almost instinctively, one feels that the 3G device is getter poorer reception. This leads to other negative thoughts, such as the device isn’t as sensitive as the previous version, or the device has a fault perhaps, or just that the 3G network coverage isn’t that good.

I haven’t noticed that call completion is any less likely with the 3G device. In fact, as pointed out in the article, I too have noticed that I can still make calls even with ‘poor’ signal strength. In fact, I have many times made a call with apparently ‘zero’ signal strength. Other users have reported similar experiences.

Nonetheless, plenty of users have been asking about those bars. One could ask why put them there at all? After all, they appear to have very little meaning. If a user wants to make a call, they will most likely go ahead and try, irrespective of how many bars are visible, unless it says ‘no service.’

As the article itself points out, there is no standard for displaying signal bars. In fact, if the bars are reporting signal strength, then this isn’t that helpful anyway. What the user really wants to know, I guess, assuming they take any notice at all, is ‘can I connect or not?’

Perhaps we should have a percentage indicator that shows the chances of completing a call. In theory, this is possible using historical measurement reports collected in the network and mapped to location. This is how operators optimise their networks in the first place (okay, that’s ignoring the numerous other parameters they measure, but it’s more or less true).

Why not just scrap the bars as a historical hang-over from ‘radio phones?’ After all, they don’t really tell us that much, especially in a 3G network. Ultimately, unless the signal is really bad, it’s not possible to know if a call will complete until you try it. And, isn’t that what users do anyway?

Surely it’s better to let the user go ahead and try making a connection and indicate that the network connection isn’t good enough if that’s the reason that the connection won’t complete. That might be more meaningful than those irritating ‘call failed’ messages that don’t tell us anything other than to try again.

I guess it’s no big deal. However, there are some quirks with the iPhone radio that ought to be fixed. I simply can’t understand why it won’t store an outbound text message until the network’s ready to send. That’s what mobiles usually do. Instead, we get the annoying ‘error sending message’ blurb that stops us dead in our tracks and forces us to retry the send manually, totally breaking the ‘fire and forget’ experience that texting is well known for. Perhaps it’s because the guys at Apple think that texting is supposed to be more like iChat than asynchronous messaging.

By the way, if you’re stuck with making a call on the iPhone, try turning 3G off. This will force the phone to use the highly optimised 2G network, which, almost certainly, still has better coverage and call completion rate than the 3G one. However, with 3G turned off, you won’t be able to call and use data at the same time. Of course, this does give rise to another question, which is why does the iPhone have a ‘3G on/off’ option in the first place? What, I wonder, do users make of that?

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