Synchronous multi-link wireless TXOP procedure
Embodiments of the present invention are drawn to a computer-implemented process for automatically synchronizing TXOPs for a multi-link device (MLD) to improve wireless network performance and prevent IDC. The novel process can be performed by a multi-link device performing a multi-link operation, and the multi-link device can act as a wireless access point or a wireless station. Independent EDCA channel access can be performed at the multi-link device on a first wireless link and a second wireless link, and a back-off counter for a first wireless STA and a back-off counter for a second wireless STA are set according to the independent EDCA channel access. A TXOP is synchronously obtained on the first wireless link and the second wireless link responsive to the back-off counters expiring, and a multi-link operation is performed at the MLD using the first wireless link and the second wireless link during the TXOP.
1. A method of transmitting data over a wireless network by a multi-link device (MLD), the method comprising:
performing independent enhanced distributed channel access (EDCA) channel access at the multi-link device on a first wireless link and on a second wireless link, wherein the multi-link device comprises:
a first wireless station (STA) associated with the first wireless link; and
a second wireless STA associated with the second wireless link;
determining that a back-off counter of the first wireless link has reached 0;
obtaining a TXOP on the first wireless link;
determining that the second wireless STA has not yet obtained a TXOP on the second wireless link;
delaying a frame exchange sequence over the first wireless link until a back-off counter of the second wireless link has reached 0;
determining that the back-off counter of the second wireless link has reached 0;
responsive to determining that the back-off counter of the second wireless link has reached 0, obtaining a TXOP on the second wireless link;
responsive to the obtaining a TXOP on the second wireless link, performing a multi-link operation at the multi-link device using the first wireless link and the second wireless link when physical carrier sensing and virtual carrier sensing indicate that the first wireless link is idle;
initiating the frame exchange sequence over the first wireless link during the TXOP on the first wireless link; and
initiating a frame exchange sequence over the second wireless link during the TXOP on the second wireless link.
2. The method as described in claim 1 , further comprising:
receiving timing accuracy information from a second multi-link device indicating that the second multi-link device can respond within a period of time equal to aSIFSTime+aSignalExtension±TimingErrorMargin measured from the end of a transmission of a soliciting frame, and
wherein the multi-link device performs the multi-link operation in coordination with said second multi-link device.
3. The method as described in claim 1 , wherein the multi-link operation comprises:
transmitting a first multi-user request to send (MU-RTS) frame using the first wireless STA over the first wireless link; and
transmitting a second MU-RTS frame using the second wireless STA over the second wireless link.
4. The method as described in claim 3 , wherein the first MU-RTS frame comprises padding that aligns an ending time of the first MU-RTS frame with an ending time of the second MU-RTS frame.
5. The method as described in claim 3 , wherein the first MU-RTS frame comprises padding that aligns reception of a first clear to send (CTS) frame with reception of a second CTS frame, and wherein the first CTS frame and the second CTS frame are transmitted responsive to the first MU-RTS frame and second MU-RTS frame, respectively.
6. The method as described in claim 5 , wherein the padding is within a padding field that aligns a TXOP of the first wireless link with a TXOP of the second wireless link.
7. The method as described in claim 1 , further comprising configuring a slot alignment of the first wireless STA to match a slot alignment of the second wireless STA.
8. A multi-link device for transmitting data over a wireless network, the multi-link device comprising:
a first wireless station (STA) associated with a first wireless link of the wireless network;
a second wireless STA associated with a second wireless link of the wireless network;
a memory for storing data; and
a processor operable to:
perform independent enhanced distributed channel access (EDCA) channel access on the first wireless link and the second wireless link;
determine that a back-off counter of the first wireless link has reached 0;
obtain a TXOP on the first wireless link;
determine that the second wireless STA has not yet obtained a TXOP on the second wireless link;
delay a frame exchange sequence over the first wireless link until a back-off counter of the second wireless link has reached 0;
determine that the back-off counter of the second wireless link has reached 0; and
responsive to determining that the back-off counter of the second wireless link has reached 0, obtain a TXOP on the second wireless link;
responsive to the obtaining a TXOP on the second wireless link, perform a multi-link operation using first wireless STA over the first wireless link and the second wireless STA over the second wireless link when physical carrier sensing and virtual carrier sensing indicate that the first wireless link is idle;
initiate the frame exchange sequence over the first wireless link during the TXOP on the first wireless link; and
initiate a frame exchange sequence over the second wireless link during the TXOP on the second wireless link.
9. The multi-link device as described in claim 8 , wherein the processor is further operable to:
receiving timing accuracy information from a second multi-link device indicating that the second multi-link device can respond within a period of time equal to aSIFSTime+aSignalExtension±TimingErrorMargin measured from the end of a transmission of a soliciting frame, and
wherein the multi-link device performs the multi-link operation in coordination with said second multi-link device.
10. The multi-link device as described in claim 8 , wherein the multi-link operation comprises:
transmitting a first multi-user request to send (MU-RTS) frame over the first wireless link; and
transmitting a second MU-RTS frame over the second wireless link.
11. The multi-link device as described in claim 10 , wherein the first MU-RTS frame comprises padding that aligns an ending time of the first MU-RTS frame with an ending time of the second MU-RTS frame.
12. The multi-link device as described in claim 10 , wherein the first MU-RTS frame comprises a padding field set according to an expected channel access latency of the second wireless STA.
13. A method of transmitting data over a wireless network by a multi-link device (MLD), the method comprising:
performing independent enhanced distributed channel access (EDCA) channel access at the multi-link device on a first wireless link and on a second wireless link, wherein the multi-link device comprises:
a first wireless station (STA) associated with the first wireless link; and
a second wireless STA associated with the second wireless link;
obtaining a transmission opportunity (TXOP) on the first wireless link;
performing physical carrier sensing and virtual carrier sensing on the first wireless link during an aSlotTime;
delaying channel access to the first wireless link until the second wireless STA has obtained an TXOP on the second wireless link to align slot boundaries for performing a multi-link operation on the first wireless link and the second wireless link; and
performing the multi-link operation at the multi-link device using the first wireless link and the second wireless link during the TXOP on the first wireless link and the TXOP on the second wireless link when physical carrier sensing and virtual carrier sensing indicate that the first wireless link is idle.