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Siemens IEEE802.11 User Manual

Page 19

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WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt

Page 19

© Siemens, 2002

IEEE802.11
2.4 GHz & 5 GHz Physical Layers

Time

Fr
equenc

y

n

2.4 GHz

Frequency Hopping Spread Spectrum

– 2/4 FSK with 1/2 Mbps

– 79 non overlapping frequencies

of 1 MHz width (US)

Frequency

Pow

e

r

Frequency

Pow

e

r

spreading

n

2.4 GHz

Direct Sequence Spread Spectrum

– DBPSK/DQPSK with 1/2 Mbps

– Spreading with 11 Bit barker Code

– 11/13 channels in the 2.4 GHz band

n

2.4 GHz High Rate DSSS Ext. (802.11b)
– CCK/DQPSK with 5.5/11 Mbps

Frequency

Pow

e

r

n

5 GHz

OFDM PHY (802.11a)

– Basic parameters identical to

HiperLAN2 PHY

– European regulatory issues

n

Baseband IR, 1 and 2Mbps, 16-PPM and 4-PPM