Cellular communication and 3G in the subway

Question

mobile connection

For a long time I have been interested in the question about the work of cellular communications and 3G at metro stations.

1) How do base stations handle the high density of GSM/2G/3G devices today?
2) What is the maximum density of passenger traffic at which there are no problems in the operation of base stations?
3) How is the environment for 3G divided when a critical threshold is reached?
4) Does it make sense to reconnect the device off / on 3G when there is no response, or does it only aggravate the situation? (perhaps new connections have a lower priority)

Perhaps there is someone from the telecom. It would be interesting to hear from the original source.

Answer 1

1. In different ways, depending on the available frequency spectrum, and permission from the owners of the metro - for the installation of additional equipment
2. There are no problems in the operation of base stations with an increase in passenger traffic. Problems arise with the provision of services due to resource overload. Solely for example - standard configurations of base stations allow serving simultaneously in 2G - from 6 to 60 subscribers, in 3G from 20 to 80 subscribers. at the same time, of course, the more subscribers, the lower the average speeds provided to each.
3. The question is not clear. What's Wednesday? critical threshold of what?
4. All connections have the same priority, the problem is that when you reconnect, you generate a significant amount of signaling information, which takes away the resources of the base station. So you yourself are wasting time while disconnecting / connecting, and people nearby can worsen the work. If 3G is not dragging at all, you can switch to 2G, where the minimum speeds are more stable.

Answer 2

3) Like in Wifi or like TDM time slots? In GSM TDM for sure, but hardly with the Internet.