RECEIVER DEFENSE USING CLEAR-TO-SEND ACKNOWLEDGMENT FRAMES

1 . A method comprising:

receiving, by an access point (AP) device operating in dual bands, a request-to-send (RTS) frame from a peer wireless device;

determining whether a channel-access period specified by the RTS frame exceeds a remaining on-channel time for a wireless band during time-division multiplexing transmission; and

in response to the channel-access period of the RTS frame exceeding the remaining on-channel time, transmitting, by the AP device, a clear-to-send acknowledgement (CTS-A) frame that reserves the channel-access period for the AP device.

2 . The method of claim 1 , further comprising adjusting, within the CTS-A frame, a length of the channel-access period to last through an expected period of time during which a subsequent RTS frame would be allowed to be transmitted by the peer wireless device.

3 . The method of claim 1 , wherein reserving the channel-access period with the CTS-A frame takes access to the channel-access period away from the peer wireless device.

4 . The method of claim 1 , further comprising generating the CTS-A frame with a destination address that is other than a source address included within the RTS frame and with a duration that is different than the duration in a CTS frame.

5 . The method of claim 1 , wherein the channel-access period is a transmission opportunity (TXoP) period for the wireless band.

6 . The method of claim 1 , wherein transmitting the CTS-A frame further comprises transmitting the CTS-A frame within a time period defined by a combination of a CTS timeout period, a distributed inter-frame space, and a re-start back-off window imposed on the peer wireless device.

7 . The method of claim 1 , further comprising transmitting, by the AP device, an absence notification CTS-A frame after the CTS-A frame and before a off-channel period of the wireless band.

8 . The method of claim 7 , wherein a second channel-access period of the absence notification CTS-A frame is longer than the channel-access period of the CTS-A frame.

9 . A method comprising:

operating, by an access point (AP) device, within a channel, in a first wireless band during time-division multiplexing transmission in dual bands;

detecting that an on-channel time period of the first wireless band is within a predetermined period of ending; and

in response to the detecting, transmitting, by the AP device, a clear-to-send acknowledgement (CTS-A) frame that reserves a channel-access period for the AP device.

10 . The method of claim 9 , further comprising setting the channel-access period for the CTS-A frame to be as long as that of an absence notification CTS-A frame.

11 . The method of claim 9 , wherein transmitting the CTS-A frame is in response to receipt of an RTS frame from a peer wireless device.

12 . The method of claim 11 , further comprising transmitting, by the AP device, an absence notification CTS-A frame after the CTS-A frame and before an off-channel period of the first wireless band, wherein a second channel-access period of the absence notification CTS-A frame is longer than the channel-access period of the CTS-A frame.

13 . An access point device comprising:

a transceiver configured to operate in dual bands; and

a processing device coupled to the transceiver, wherein the processing device is to:

cause the transceiver to receive, from a peer wireless device, a request-to-send (RTS) frame;

determine whether a channel-access period specified by the RTS frame exceeds a remaining on-channel time for a wireless band during time-division multiplexing transmission; and

in response to the channel-access period of the RTS frame exceeding the remaining on-channel time, cause the transceiver to transmit a clear-to-send acknowledgement (CTS-A) frame that reserves the channel-access period for the transceiver.

14 . The access point device of claim 13 , wherein the processing device if further to adjust, within the CTS-A frame, a length of the channel-access period to last through an expected period of time during which a subsequent RTS frame would be allowed to be transmitted by the peer wireless device.

15 . The access point device of claim 13 , wherein reserving the channel-access period with the CTS-A frame takes access to the channel-access period away from the peer wireless device.

16 . The access point device of claim 13 , wherein the processing device is further to generate the CTS-A frame with a destination address that is other than a source address included within the RTS frame and with a duration that is different than the duration in a CTS frame.

17 . The access point device of claim 13 , wherein the channel-access period is a transmission opportunity (TXoP) period for the wireless band.

18 . The access point device of claim 13 , wherein, to cause the transceiver to transmit the CTS-A frame, the processing device is further to cause the transceiver to transmit the CTS-A frame within a time period defined by a combination of a CTS timeout period, a distributed inter-frame space, and a re-start back-off window imposed on the peer wireless device.

19 . The access point device of claim 13 , wherein the processing device is further to cause the transceiver to transmit an absence notification CTS-A frame after the CTS-A frame and before an off-channel period of the wireless band.

20 . The access point device of claim 19 , wherein a second channel-access period of the absence notification CTS-A frame is longer than the channel-access period of the CTS-A frame.