Siemens IEEE802.11 - Manual (Page 35)

, © Siemens, 2002
STA “B”
cannot receive
data from
STA “A”
Problem – Stations contending for the medium do not Hear each other
STA “B” STA“A”
RTS-Range
Access Point
CTS-Range
RTS
CTS
STA A
AP
STA B
DIFS
STA “B” cannot detect carrier from STA “A”
Next MPDU
Time period to defer access
is based on duration in CTS
Back off after defer
Ack
Data
Solution – Optional use of the Duration field in RTS and CTS frames with AP
“Hidden Node” Provisions