-
I'm not sure what the point is here? Mobile phones connect over the cellular network to do voice and data, which is what the Wikipedia article is describing (as basically a network cell will record all devices that are connected to it at a given time and log that). But that data only indicates that a phone was in the area covered by that particular base station, it can't accurately say whereabouts in the cell the phone is. You can get an approximate location, accurate down to about 10 metres, by triangulating the data from the adjacent cells, but it's not as accurate as GPS, which is accurate down to 1 metre.
andyp-
But that data only indicates that a phone was in the area covered by that particular base station
Signal strength is usually recorded too, along with round-trip-times. With a whole series of that data it's possible to get a rough idea of a phone's path through a cell area, especially when combined with data from neighbouring towers.
This is after-the-fact analysis though and works well for analysing simple transits through the area covered by a cell tower. It's not great for instantaneous location (stuff like [advanced] forward link trilateration is way better), or when the phone is dawdling within a single cell tower's vicinity for a long period.
Anyway. Enough tin-hattery. Mobile phones are rarely completely spent when it seems they won't charge. The power buttons are software controlled, not hardware, so there's usually enough power to keep the circuits that handle power button polling going. But this is a miniscule amount of power compared to receiving and processing GPS signals, listening for nearby bluetooth devices, let alone powering the baseband modem to send data out over 3G/4G/5G or Wifi.
Greenbank
Wikipedia disagrees?
https://en.m.wikipedia.org/wiki/Cellphone_surveillance