Chapter 3
LTE/SAE Overview
3.1 Introduction
LTE refers to the long-term evolution of the 3GPP radio network—it can be considered as a synonym for the evolved UMTS Terrestrial Radio Access Network (UTRAN), as it defines the new LTE radio interface. It enhances the previous performance of the IP domain of the networks, and increases the flexibility of radio network design. It provides several channel bandwidths, which is useful in general network evolution, including refarming strategies. LTE can use either Frequency Division Duplex (FDD) or Time Division Duplex (TDD) modes. It is based on Orthogonal Frequency Division Multiple Access (OFDMA) technology in the downlink, and SD-TDMA in the uplink, which optimizes the radio interface for the mobile environment, especially in presence of multipath radio components and fast fading of multiple signals. It can also use the latest technologies on top of the basic solution, including 64 QAM (64 state Quadrature Amplitude Modulation) and different configurations of the Multiple Input Multiple Output (MIMO) antennas.
Evolved UTRAN contains only one type of base station, called eNodeB—referring to the evolved NodeB in previous network element solutions of 3GPP networks. In other words, there is no separate controller element in LTE but the respective functionality has been concentrated on the base station side.
The rest of the network, which is not related to the radio, is called SAE, referring to the ...
