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Introduction to Power Management in Portable Personal Devices
technique, as opposed to DSSS ’
s “ spread ” and FHSS ’ s “ hopping ” techniques, by slowing
the symbol rate enough so that it is longer than the delay spread. The data is mapped across
several lower-speed signals effectively blocking interference because transmission is spread
across all sub-carriers in parallel. Table 1.3 shows a comparison of the three techniques.
Table 1.3 : DSSS, FHSS, and CODFM Comparison
DSSS FHSS COFDM
Band 2.4 GHz 2.4 GHz 5 GHz
Standard IEEE 802.11b IEEE 802.11b, Bluetooth IEEE 802.11a
Carrier ...