FDM Vs. OFDM

What is the difference between FDM & OFDM?
Where they are using ?(MB OFDM in UWB, OFDM in wireless)

OFDM is used in LTE (which is 3.9G and LTE advanced which is 4G).

OFDM uses many carriers per a given spectrum that are very close to each other, however in an exact distance one from another so they remain orthogonal to each other.

FDM uses only a single carrier per spectrum.
2G and 3G (3G uses FDM together with CDMA) use FDM.