Apparently, the signal bars on a mobile phone don't mean much

4 Feb 2008 - 11:29am
700 reads
Murli Nagasundaram
2007

Is an interface component like this useful even if it is not very
meaningful? What if the signal bars were eliminated completely? -- murli

http://www.newscientist.com/blog/technology/2008/02/mobile-bars-what-are-they-for.html

Signal bars - what are they for?
<http://www.newscientist.com/blog/technology/uploaded_images/cell_phone-741856.jpg>There's
an icon in the corner of every mobile phone's screen that we are all
familiar with. But do we really know what those signal bars mean?

That question was raised for me by this
blogger<http://liftlab.com/think/nova/2008/01/26/seamful-design-and-cell-phone-reception-bars/>,
who also links to an interesting discussion thread on the matter
here<http://ask.metafilter.com/60227/What-do-cell-phone-reception-bars-mean?>.
Various people pitch in, some with knowledge of working in the handset or
network operator industry. They give a suite of reasons that the bars are
not much use, including:

- There are no industry standards for what 'one bar', 'two bars', etc
means
- Some phones estimate signal quality when idle, only measuring it
properly when you try to call, which is misleading
- Under the CDMA protocol used in North America, bar represent signal
strength, but not a variable dubbed
EC/I0<http://www.arcelect.com/Cell_modem_Glossary.htm#EC/I0>,
which is the portion of that signal that is usable

Interesting points. But if we want to improve things, the technical details
are not really important. We need to decide what we want to know about our
signal first.

At the moment, phone manufacturers give us little idea of what to expect.
But people still read a lot of information into signal bars. It's not
unusual to hear people boast "I've got five bars" when a friend struggles to
connect. I often hear people comparing signal strength on parts of London's
metro network where the tunnels are not deep enough to completely block
signals.

But really, most of us have no idea what those bars mean. I think we need to
rethink them, with an indicator directly related to what you can do with the
signal you have.

How about using these four categories:

- No signal
- Text messaging only
- Poor call quality likely
- No problems

I'll admit that's not perfect. For example, an indication of how much
bandwidth you have for data transfer could be useful. Can anyone else think
of a better way of representing signal strength and what you can do with it?

Tom Simonite, online technology reporter

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