Originally Posted by
nmenaker
since all these devices require a GPS signal and location to function, it would seem that they should automagically know exactly where they are. That location information is relayed back to the mothership and I am sure incorporated into at least the company's view of "network" coverage.
Correct. Part of it is to ensure that the device is being used where they have coverage (and make sure the right coverage is broadcast.) T-Mobile knowing, and the cell site being programmed to know where its neighbour sites are two different things. The other GSM carriers in the area also need to know about the site so that they can programme theirs appropriately for roamer handoffs, and help reduce interference.
A few years ago, when I was still in cellular, a new site was lit. It caused interference with a different carrier's site across the street. They didn't know what was going on so they boosted their power to compensate for the interference, knocked the new site off the air, and caused handoff problems with other nearby sites when they tried to compensate.
Long story short, it is complicated.