Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)



802.11a

Orthogonal Frequency Division Multiplexing (OFDM)

is a physical layer encoding technology for transmitting signals through the RF. This method breaks one high-speed data carrier into several lower-speed carriers. These are in turn transmitted in parallel across that particular RF spectrum. The 802.11a subcommittee has elected to use the transmission technique for their standard in the 5 GHz UNII (Unlicensed National Information Infrastructure) bands. OFDM is also used in the 2.4 GHz ISM band as the physical layer standard for the 802.11g standard.





802.11b/g

Direct-sequence spread spectrum (DSSS) and orthogonal frequency division multiplexing (OFDM)

DSSS Direct-sequence spread spectrum. A type of spread spectrum radio transmission that spreads its signal continuously over a wide frequency band.