In this chapter, a more detailed overview of OFDM or Orthogonal Frequency-Division Multiplexing will be given. OFDM is the transmission scheme used for 3GPP LTE and is also used for several other radio-access technologies, for example WiMAX  and the DVB broadcast technologies .
Transmission by means of OFDM can be seen as a kind of multi-carrier transmission. The basic characteristics of OFDM transmission, which distinguish it from a straightforward multi-carrier extension of a more narrowband transmission scheme as outlined in Figure 2.5 in the previous chapter, are:
• The use of a typically very large number of relatively narrowband subcarriers. In contrast, a straightforward ...