Siemens IEEE802.11 Tutorial page 43

Infrastructure Beacon Generation
Beacon Interval
X
Busy Medium
Beacon
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.
WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt
"Actual time" stamp in Beacon
X X X
Time Axis
Page 43 © Siemens, 2002