Picture from: http://en.wikipedia.org/wiki/T-Mobile_G1
No, this blog post is not about T-mobile G1. I just post the image because it's nice.
I read a post that talks about basics of how mobile phone network works - Peering Inside a Mobile Phone Network. Some of them are easy to understand (item 1, 4); some are pretty interesting(item 3, 5. Here is the list of items it mentions:
- How Your Calls Follow You
- How Calls Work in Cars and Planes
- Why Text Messages Work When Your Phone Won't Ring
- Why Your Battery Sometimes Dies Faster
- Why the iPhone GPS is Faster than Your Car GPS
In order to support 911 emergency services, all mobile phone systems now try to track your physical location down to about a minimum of 150 meters (it's a bit different outside the United States). Thus your phone has a good rough idea where you are before the GPS even starts.Although the author wrote the article with iPhone/ATT in mind, in general, it should apply to every phone/provider.