OFDM Tutorial

Here is a good tutorial for OFDM：
Orthogonal Frequency-Division Multiplexing (OFDM): FAQ Tutorial
The wiki page is at http://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing

The most interesting Q&A is the last one:

Q: Is there anything better than OFDM?

A: Not right now. What makes OFDM even better is MIMO, the multiple-input multiple-output antenna technology. It is currently used in 802.11n Wi-Fi and the forthcoming LTE. Look for MIMO in another FAQ Tutorial.