I am not sure but the way from UMTS to LTE was purely technical. In UMTS the sender just spams out the signal for all receivers and you need to retransmit more

I am not sure but the way from UMTS to LTE was purely technical. In UMTS the sender just spams out the signal for all receivers and you need to retransmit more because the error correction keeps kicking in. So the more devices in a cell the higher the latency, variance and lower the bandwidths. With LTE each device is measured by the tower about how well it can receive data and the tower time slices specifically for this device. So when the tower sends there, it does not send to any other device. (That's my understanding of the situation)