Spread Spectrum Transmission Methods
Newer 802.11 standards use OFDM:
Orthogonal Frequency Division Multiplexing.
OFDM divides the entire channel into smaller subcarriers (subchannels).
It sends part of the signal in each subcarrier.
Information is sent redundantly among the subcarriers,so the whole message will get through even if some subcarriers are bad
Using smaller channels gives more precise signal spreading
than spreading the signal over the entire channel.
This in turn allows much faster transmission speeds.