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Testing and Mapping a Cellular Data Network?
bgsneeze writes "In order to resolve an ongoing issue with a vendor, I have been trying to find a way to test different 3G data devices empirically. I would like to be able to chart signal strength, latency, and bandwidth. I would also like to create a map of the coverage area. I have a test 3G card from three different providers. I would like to be able to travel with the setup to several different locations and run tests. What software or techniques would Slashdotters use to test the different devices? Are there any free or open source software packages that will do this?"
Why do it yourself when you can just wait for Google to announce they did it accidentally ;-)
Empirical testing with wireless CELLULAR networks can be very tricky; A few things that you will need to keep in mind is that for testing, you want to make sure your transceiver setup is perfectly reproducable; Same card, same ANTENNA, same position of antenna. When performing your testing, your signal strength will depend on several factors: Distance from the site, antenna type/gain, and specifically what sector/node on the site you happen to be on. while driving in a straight line, you may find that you approach steep nulls near the border of a cells sector boundary. Alot depends on the ability of your particular card to handle the handoff between sectors/sites.
Your latency measurements will also vary according to the individual usage of the sector/site that you are currently on, and additionally vary with time and also variable bandwidth allocation to the sites from the main switch.
There are quite a few test sets and software suited that are commercially available and are tailored for this use, and are used heavily by the mobile data/cellular industry in their drive testing and coverage verification methodologies.
Good luck to you on your testing.
--ToO
These are simply links to the coverage maps advertised by the providers, in which service quality is frequently exaggerated, if not blatantly false.
For example, AT&T (my provider) claims "good" coverage in two neighborhoods in my home town, Pasadena, where I know for a fact that there is no coverage, or worse, sporadic one-bar-then-no-bar coverage that drains my cellphone battery in an hour. And even worse, they show "best" coverage throughout San Marino, a town in which I can never make or receive calls on AT&T.
I can see the fnords!
Can you ping me yet?
How about now?
However, if you have 3G cards from three different providers, and your company wants to know which one to use to deploy their new fancy device, and they don't actually trust any of those providers (for good reason), it may be a good idea to go out and make sure with real world tests before you jump to one provider or another.
Qxe4
A bigger number on the same device probably means you have a better signal. A 'two' on one device could be equivalent to a 'five' on another or a 'one' on a third. There is no standard that is used across the industry, or even across all devices from a given manufacturer.
When a device manufacturer gets customer reviews that say "I only get one bar with your phone but two from company X" the device manufacturer can either try and explain repeatedly that their one bar is better than X's two bars and that unlike X you can still make phone calls on our device on one bar. Or they can just double the number of bars reported on the next model so they don't look worse than X.
Which do you think they do?
To do a real test you need to use a constant antenna and location, attenuating the signal gradually until each device stops functioning. The amount of attenuation it can take is a crude indicator of the quality of the radio.