It's a long time since I worked on mobile phones but in GSM the phone has to keep an internal of the tower it's connected to and the nearest neighbours in order to manage handover smoothly (ie. With dropping calls). I suspect 3G is similar.
In GSM the phone also had to know the distances to each tower +/-500m in order to adjust the timings for communication with the tower.
(It's 8 years since I did is stuff so memory might be off on the numbers a bit :-)
In GSM the phone also had to know the distances to each tower +/-500m in order to adjust the timings for communication with the tower.
(It's 8 years since I did is stuff so memory might be off on the numbers a bit :-)