802.11 is the [http://standards.ieee.org/getieee802/802.11.html specification] for wireless ethernet which is what all of the ["802.11a"], ["802.11b"] and ["802.11g"] specifications are based on. 802.11 provides three PHY methods: ["FHSS"], ["DSSS"], and Infrared.
The FHSS method uses one of these for modulation (and FHSS for spectral spreading) (in order of rate improvement):
2-level GaussianFrequencyShiftKeying (2GFSK)
4-level GaussianFrequencyShiftKeying (4GFSK)
Frame headers are transmitted with 2GFSK at 1 Mb/s but the data portion's modulation (and rate) is variable.
The ["DSSS"] method uses one of these for modulation (and ["DSSS"] for spectral spreading) (in order of rate improvement):