Operating principles of the LTE radio interface

During the 2000s, it quickly became apparent that the UMTS (Universal Mobile Telecommunications System) system, even in its high-speed version (High Speed Data Packet Access), would remain limited in terms of throughput, latency and capacity, due to its CDMA-based transmission and the complexity of its architecture. In 2004, the 3GPP (3 ^rd Generation Partnership Project) therefore launched a working group for long-term evolutions, or LTE for Long Term Evolution, of the radio interface for 3rd generation systems. The group's work has led to the specification of a completely new radio interface, and has triggered a similar effort to completely overhaul the architecture of core networks. The whole of this new system is commonly referred to as LTE, although the term LTE applies only to the radio interface.

This article focuses on the presentation of the radio interface while presenting the general architecture of the system. 3GPP produces specification documents in successive waves called Releases. The LTE radio interface is defined in a set of recommendations published with Release 8 (previous releases only include GSM and UMTS systems). This article presents the essential features and is based on Release 8. However, what is presented remains valid for subsequent releases.