Siemens IEEE802.11 manual Hidden Node Provisions, STA a STA B

“Hidden Node” Provisions

Problem – Stations contending for the medium do not Hear each other Solution – Optional use of the Duration field in RTS and CTS frames with AP

	CTS-Range
STA “B”
cannot receive	RTS-Range
data from
STA “A”

STA “B” Access Point STA“A”

DIFS

STA A

AP

STA B

	RTS			Data
		CTS			Ack
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

, © Siemens, 2002