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The IEEE define 802.11 standard includes a common Medium Access
Control (MAC) Layer, which defines protocols that govern the operation
of the wireless LAN. In addition, 802.11 comprises several alternative
physical layers that specify the transmission and reception of 802.11
frames. Let's take a closer look at the 802.11b Physical Layer, which
uses direct sequence spread spectrum (DSSS [1]) technology to support
operation of up to 11Mbps data rates in the 2.4GHz band.
As with other 802.11 Physical layers, 802.11b includes Physical Layer
Convergence Procedure (PLCP [2]) and Physical Medium Dependent (PMD
[3]) sub-layers. These are somewhat sophisticated terms that the
standard uses to divide the major functions that occur within the
Physical Layer. The PLCP prepares 802.11 frames for transmission and
directs the PMD [4] to actually transmit signals, change radio
channels, receive signals, and so on
* 802.11B PHY revealed [5]
DATA RATE
MODULATION TECHNOLOGY
11Mbps
CCK [6]
5.5Mbps
CCK [7]
2 Mbps
QPSK [8]
1 Mbps
BPSK [9]
Links:
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[1] http://melbournewireless.org.au/?DSSS
[2] http://melbournewireless.org.au/?PLCP
[3] http://melbournewireless.org.au/?PMD
[4] http://melbournewireless.org.au/?PMD
[5] http://www.wi-fiplanet.com/tutorials/article.php/2107261
[6] http://melbournewireless.org.au/?CCK
[7] http://melbournewireless.org.au/?CCK
[8] http://melbournewireless.org.au/?QPSK
[9] http://melbournewireless.org.au/?BPSK
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