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:
Carrier aggregation that supports up to 5 component carriers (e.g. 1 primary and 4 secondary). (Basic LTE-A)
Simultaneous PUCCH and PUSCH (Advanced LTE)
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 the EPCs, with each other, and with user equipment (UE).
LTE standards are continually changing as the technology evolves. The information presented here, therefore, is also subject to change. For the latest information on these standards, visit the 3GPP website and refer to 3GPP Technical Specifications 36.211 and 36.212.
Keysight Technologies has the broadest set of 3GPP LTE design and test tools for every stage of the lifecycle—design automation, signal generation and analysis, protocol test, network deployment and service assurance. In addition, Keysight provides a number of LTE-focused learning resources and events. For more information, visit www.keysight.com/find/lte.