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Infrastructure beacon generation – Siemens IEEE802.11 User Manual

Page 43

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

Page 43

© Siemens, 2002

Time Axis

Beacon Interval

X

X

X

X

"Actual time" stamp in Beacon

Beacon

Busy Medium

Infrastructure Beacon Generation

n

APs send Beacons in infrastructure networks.

n

Beacons scheduled at Beacon Interval.

n

Transmission may be delayed by CSMA deferral.
– subsequent transmissions at expected Beacon Interval
– not relative to last Beacon transmission
– next Beacon sent at Target Beacon Transmission Time

n

Timestamp contains timer value at transmit time.