Interference suppression methods for 802.11
First Claim
1. A method for spoofing stations while transmitting data through a medium, the method comprising:
- setting a duration value to a value other than a time period for a predetermined subsequent message transmission;
sending a first signal containing the duration value, wherein at least one of the stations is an obeying station that updates a network allocation vector in accordance with the duration value if a second signal is detected after the first signal and that resets the network allocation vector if the second signal is not detected after the first signal; and
sending a third signal containing the duration value, wherein if the at least one station resets the network allocation vector because the second signal is not detected after the first signal, the at least one station updates the network allocation vector in accordance with the duration value contained in the third signal.
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Accused Products
Abstract
An 802.11 source station transmits a signal with the duration field other than that required for the transmission to prevent transmission by other stations during known sequences. Thus, the source station uses the duration field to spoof the actual time the medium will be occupied, to stations within range of the signal. A station within range of the transmitted signal will check the duration field of the transmitted signal, and update the station'"'"'s network allocation vector. Thus, the station will not transmit because the station'"'"'s network allocation vector indicates that the medium is in use, even though the station maybe unable to hear the carrier. Accordingly, spoofed stations may, for example, 1) delay transmission until a more critical transmission has completed, 2) allow unknown or foreign protocol to have preferential use of the medium, 3) prevent interference from hidden stations, and 4) allow sharing of the medium by overlapping basic service sets.
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Citations
19 Claims
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1. A method for spoofing stations while transmitting data through a medium, the method comprising:
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setting a duration value to a value other than a time period for a predetermined subsequent message transmission; sending a first signal containing the duration value, wherein at least one of the stations is an obeying station that updates a network allocation vector in accordance with the duration value if a second signal is detected after the first signal and that resets the network allocation vector if the second signal is not detected after the first signal; and sending a third signal containing the duration value, wherein if the at least one station resets the network allocation vector because the second signal is not detected after the first signal, the at least one station updates the network allocation vector in accordance with the duration value contained in the third signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A machine-readable medium having stored thereon a plurality of executable instructions, the plurality of instructions comprising instructions to:
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set a duration value to a value other than a time period for a predetermined subsequent message transmission; send a first signal containing the duration value, wherein at least one of the stations is an obeying station that updates a network allocation vector in accordance with the duration value if a second signal is detected after the first signal and that resets the network allocation vector if the second signal is not detected after the first signal; and send a third signal containing the duration value, wherein if the at least one station resets the network allocation vector because the second signal is not detected after the first signal, the at least one station updates the network allocation vector in accordance with the duration value contained in the third signal. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification