4G explained: The streaming generation.
4G moved mobile broadband to an IP-based network. Carrier aggregation and multiple antennas increase capacity; VoLTE carries calls over LTE. Signal quality, congestion and device support still shape the experience.
LTE and an IP core
LTE improves spectral efficiency and uses an all-IP packet core for services. Its downlink uses OFDMA; original LTE uplink uses SC-FDMA. LTE-Advanced adds further capabilities.
Carrier aggregation and MIMO
Carrier aggregation combines radio carriers. MIMO uses multiple antennas to carry or receive spatial streams when conditions support it. Both depend on what the device and network can negotiate.
VoLTE and everyday performance
VoLTE uses an IP multimedia subsystem for voice over LTE. It can allow voice and LTE data together, subject to support. Real speeds depend on signal quality, spectrum and cell load, not just the number of signal bars.