LTE standards are continually changing as the technology evolves. The information presented here is subject to change. Refer to 3GPP Technical Specification 36.211 and 3GPP Technical Specification 36.212.
3GPP Long Term Evolution (LTE) moves beyond current 3G wireless communications capabilities to provide increased peak data rates, improved spectral efficiency, and reduced user plane and control plane latency. To accomplish these goals, LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) for the downlink and Single Carrier Frequency Division Multiple Access (SC-FDMA) for the uplink. OFDMA was chosen for its high data rate capacity and its high spectral efficiency. SC-FDMA was chosen for its lower peak to average power ratio (PAPR) to maximize battery life in mobile devices. LTE achieves a peak downlink data rate of 100 Mbps and a peak uplink data rate of 50 Mbps with a 20 MHz bandwidth.
LTE enhances Universal Terrestrial Radio Access (UTRA) performance while maintaining compatibility with earlier UTRA systems and other wireless technologies such as WiMax™ and WLAN.
Other key features of LTE include the following:
Scalable bandwidth: 1.4 MHz, 3.0 MHz, 5.0 MHz, 10 MHz, 15 MHz, and 20 MHz.
Downlink modulation types: QPSK, 16-QAM, and 64-QAM
Uplink modulation types: QPSK, 16-QAM, and 64-QAM
FDD and TDD operating modes
IP-based, packet-switched architecture
MIMO capability, up to 8 X 8 MIMO
LTE employs a new network architecture made up of multiple Evolved Packet Cores (EPCs) that communicate with each other and with evolved universal terrestrial radio access network base stations (eNBs). Each EPC contains a Mobile Management Entity (MME) and a System Architecture Evolution Gateway (SAE). The eNB stations communicate with Evolved Packet Cores (EPCs), with each other, and with user equipment (UE).