O'Reilly Article: "802.11g's Extreme Emergence"
The 802.11g specification uses a relatively new method of encoding
bits onto radio waves in such a way as to squeeze up to 54 Mbps of
raw data across a single channel. Apple has embraced this new
technology in its AirPort Extreme radio cards. This article explains
how it works.
http://www.oreillynet.com/pub/a/wireless/2003/01/23/80211g.html