[_abox]

In 2G GSM there was this limit, because GSM used very strictly managed timeslots for each call. If a phone was too far away, its signal would arrive out of bounds of the timeslot and this was the reason. The protocol didn't have any compensation built in.

However 3G and onwards were based on CDMA tech (which was the competing 2G tech to GSM), which is very different. CDMA doesn't have strictly managed cells, but rather the basestation picks the signals out of a cacaphony (very simplified). So the same issue doesn't apply.

2G was much more static than CDMA, it had a strict capacity of a number of calls per cell. But the range (up to this 30km) was pretty good because when a phone transmitted the air was clear. CDMA cells used to 'breathe': Have much lower reach during busy times (because weak signals could no longer be identified) so gaps could drop in the network. ON the other hand, 2G got busy with a fixed capacity.

2G did have prioritisation though when the network was full. If you called 112 (the international emergency number) it would kick someone else off to make space for you.