Siemens IEEE802.11 Manual do Utilizador descarregar pdf (Página 27)

WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 27 © Siemens, 2002

… when will 5 GHz WLANs come?

n IEEE802.11b (2.4 GHz) is now taking over the market.

n There are developments to enhance IEEE802.11b for

– more bandwidth (up to 54 Mbit/s)

– QoS (despite many applications do not need QoS at all)

– network issues (access control and handover).

n 5 GHz systems will be used when the 2.4 GHz ISM band

will become too overcrowded to provide sufficient

service.

– TCP/IP based applications are usually very resilient

against ‘error proune’ networks.

n Issues of 5 GHz systems:

– Cost: 5 GHz is more expensive than 2.4 GHz

– Power: 7dB more transmission power for same distance

– Compatibility to IEEE802.11b/g necessary

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Siemens IEEE802.11 Manual do Utilizador Página 27