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IEEE 802.11n will give us "protection mechanisms to the nth degree" if I may coin a phrase. Here is an example:

9.2.5.4.1 Dual CTS Protection

"If the Dual CTS Protection subfield has value 1 in the beacons transmitted by its AP, a non-AP STA shall start a TXOP with an RTS directed at the AP. The AP shall respond with a dual CTS (CTS1 followed by CTS2) separated by PIFS.

"The dual CTS response only applies to the AP, a non-AP STA shall always respond to an RTS request with a single CTS.

"If dual CTS Protection is enabled, the AP should protect STBC TXOPs with a non-STBC CTS-to-self and non-STBC TXOPs with an STBC CTS-to-self. The AP should continue PIFS after the CTS, to allow for a collision detect.

"The protection frames shall set a NAV for the whole duration of the STBC sequence.

"STBC control frames shall be transmitted in response to received STBC frames if the Dual CTS Protection bit is set. Non-STBC control frames shall be used otherwise."

I hope this helps. Thanks. /criss