Long-Term Evolution
Introduction
Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements. LTE is the natural upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. The different LTE frequencies and bands used in different countries mean that only multi-band phones are able to use LTE in all countries where it is supported.
History
The LTE wireless communication standard was developed by the 3rd Generation Partnership Project (3GPP), a collaboration between groups of telecommunications associations. The aim was to improve the Universal Mobile Telecommunications System (UMTS) mobile phone standard to cope with future technology evolutions. Work on LTE began in 2004, and the first LTE release was made in December 2008. Since then, the standard has been revised and updated through various releases by the 3GPP.
Technology
LTE is based on Spectrum radio frequencies and a technology called Orthogonal Frequency Division Multiplexing (OFDM). OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. Multiple closely spaced orthogonal sub-carrier signals with overlapping spectra are used to carry data on several parallel data streams or channels.
Network Architecture
The LTE network architecture is designed to support packet-switched traffic with seamless mobility. It is a major design shift from the circuit switched architecture used in earlier cellular networks. The architecture includes the Evolved Packet Core (EPC), also known as SAE (System Architecture Evolution), and the eNodeB, or base station.
Performance
LTE provides downlink peak rates of 300 Mbit/s, uplink peak rates of 75 Mbit/s and QoS provisions permitting a transfer latency of less than 5 ms in the radio access network. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz and supports both frequency division duplexing (FDD) and time-division duplexing (TDD).
Deployment
The first commercial LTE networks were launched in Oslo and Stockholm by TeliaSonera in December 2009. LTE is now common throughout most parts of the world. Different countries and regions use different frequency bands for LTE.
Future of LTE
The future of LTE includes the ongoing development of LTE Advanced and LTE Advanced Pro, which are standardized by the 3GPP as a major enhancement of the LTE standard. These technologies increase data rates by using a different radio interface and improved core network.