In this chapter, a more detailed overview of OFDM or Orthogonal Frequency Division Multiplexing will be given. OFDM has been adopted as the downlink transmission scheme for the 3GPP Long-Term Evolution (LTE) and is also used for several other radio technologies, e.g. 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 3.5 in the previous chapter, are: