LTE, the radio technology path towards 4G

Evolved Universal Terrestrial Radio Access (EUTRA), known as the Long Term Evolution (LTE) technology, brings cellular communication to the fourth generation (4G) era. In this article, we discuss the most important characteristics of LTE; its simplified network architecture which allows ultimate means for adaptation of the radio transmission to the Internet packet traffic flows and to the varying channel states. LTE radio resource management is based on time–frequency scheduling, fast feedback between the transmitter and receiver, and nearly optimal adaptation of transport formats. Yet, the radio system is simple and cost efficient to manage from the evolved packet core network, having a server architecture with IP tunnels. The mobility states and resource allocation allow power save operation of the User Equipment when not actively communicating. In addition, we brief the key results on the LTE baseline performance for paired and unpaired frequency bands, i.e. the two duplex modes.