Point Coordination Function (Pcf) - Siemens IEEE802.11 Tutorial

Point Coordination Function (PCF)

Access
Beacon
Point
Stations
n
Optional PCF mode provides alternating contention free and
contention operation under the control of the access point
n
The access point polls stations for data during
contention free period
n
Network Allocation Vector (NAV) defers the contention traffic until
reset by the last PCF transfer
n
PCF and DCF networks will defer to each other
n
PCF improves the quality of service for time bounded data
WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt
CFP repetition interval
Contention Free Period
D1+Poll
U1+ACK
D2+Poll CF end
U2+ACK
Contention Period
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