IEEE 802.11a and IEEE 802.11b

IEEE 802.11a

-Makes use of 5-GHz band

-Provides rates of 6, 9 , 12, 18, 24, 36, 48, 54 Mbps

-Uses orthogonal frequency division multiplexing (OFDM)

-Subcarrier modulated using BPSK, QPSK, 16-QAM or 64-QAM

IEEE 802.11b

-Provides data rates of 5.5 and 11 Mbps

-Complementary code keying (CCK) modulation scheme

IEEE 802.11 Architecture

Distribution system (DS)

Access point (AP)

Basic service set (BSS)

-Stations competing for access to shared wireless medium

-Isolated or connected to backbone DS through AP

Extended service set (ESS)

-Two or more basic service sets interconnected by DS