Siemens IEEE802.11 - Manual (Page 43)

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.