Group addressed frame wireless transmission for constrained multi-link operation
Multi-link operations can provide higher network throughput and improved network flexibility compared to traditional techniques for wireless communication. Embodiments of the present invention provide a method of frame transmission that prevents constrained MLDs from transmitting and receiving frames on multiple links simultaneously using a novel and reliable group addressed frame transmission schedule for constrained MLDs. Group addressed frames are frames that are transmitted to several devices (e.g., broadcast) listening on a wireless link. It is important to carefully schedule group addressed frames for reception by MLDs to prevent IDC interference. According to some embodiments, group addressed frames are only transmitted when all MLDs listening on a wireless link are not transmitting data to prevent IDC interference.
1. A method of transmitting a group addressed frame, the method comprising:
at an access point (AP) multi-link device (MLD), determining that a first non-AP MLD is wirelessly transmitting over a first wireless link of a non-simultaneous transmit and receive (NSTR) link pair;
the AP MLD wirelessly transmitting an individually addressed frame to a second non-AP MLD over a second wireless link of the NSTR link pair; and
the AP MLD wirelessly transmitting a group addressed frame to be received by the second non-AP MLD over the second wireless link after the first non-AP MLD is done transmitting, wherein the first non-AP MLD and second non-AP MLD refrain from transmitting on the NSTR link pair during transmission of the group addressed frame without changing wireless links.
2. The method of claim 1 , wherein the wirelessly transmitting the individually addressed frame does not solicit an immediate response from the second non-AP MLD when reception of the immediate response would overlap with the transmitting the group addressed frame.
3. The method of claim 1 , wherein the NSTR link pair comprises: a 5 GHz wireless link; and a 6 GHz wireless link.
4. The method of claim 1 , further comprising the AP MLD providing scheduling information indicating a schedule for transmitting group addressed frames, wherein the non-AP MLD does not access the wireless link when the group addressed frames are scheduled to be transmitted according to the scheduling information.
5. The method of claim 1 , further comprising:
accessing a link configuration provided by the non-AP MLD indicating that the non-AP MLD is listening for group addressed frames on the wireless link; and
the AP MLD refraining from scheduling a frame exchange sequence with the non-AP MLD on the wireless link that overlaps with transmission of the group addressed frame.
6. The method of claim 1 , further comprising:
transmitting scheduling information to the non-AP MLD indicating a schedule for transmitting the group addressed frame; and
the non-AP MLD refraining from transmitting on the wireless link when the group addressed frame is scheduled to be transmitted according to the scheduling information.
7. The method of claim 6 , wherein the scheduling information comprises a broadcast target wake time (TWT) element, and further comprising preventing channel access by the non-AP MLD during a TWT service period indicated by the broadcast TWT element.
8. The method of claim 7 , wherein the broadcast TWT element comprises a Broadcast TWT Recommendation subfield equal to 0 and a Broadcast TWT ID equal to 0.
9. The method of claim 6 , further comprising assigning a first association ID (AID) to the wireless link and a second AID to a second wireless link of the NSTR link pair, wherein the first and second AID indicate if broadcast data is buffered on a respective link.
10. The method of claim 9 , wherein the first AID and second AID are carried in a virtual bitmap of a Traffic indication map (TIM) information element.
11. The method of claim 1 , wherein the wirelessly transmitting the group addressed frame comprises wirelessly transmitting the group addressed frame according to a schedule that substantially prevents in-device coexistence (IDC) interference on NSTR link pair.
12. A method of transmitting a group addressed frame, the method comprising:
accessing an indication from a non-access point (AP) multi-link device (MLD) at an AP MLD that indicates that the non-AP MLD is listening for group addressed frames on a wireless link; and
scheduling a group addressed frame for transmission at the AP MLD based on the indication, wherein the wireless link is associated with to a non-simultaneous transmit and receive (NSTR) link pair, wherein the non-AP MLD is operable to communicate with the AP MLD using the NSTR link pair, and wherein further the scheduling comprises preventing a frame exchange sequence from being scheduled that overlaps with a transmission of a group addressed frame to be received by the non-AP MLD on the NSTR link pair without changing wireless links.
13. The method of claim 12 , wherein the NSTR link pair comprises: a 5 GHz wireless link; and a 6 GHz wireless link.
14. The method of claim 12 , wherein the scheduling a group addressed frame further comprises scheduling the group addressed frame to substantially prevent in-device coexistence (IDC) interference on NSTR link pair.
15. A method of transmitting a group addressed frame, the method comprising:
transmitting scheduling information to a non-access point (AP) multi-link device (MLD) indicating a schedule for transmitting a group addressed frame over a wireless link; and
scheduling a group addressed frame for transmission at the AP MLD over the wireless link in accordance with the scheduling information, wherein the wireless link is associated with to a non-simultaneous transmit and receive (NSTR) link pair, wherein the non-AP MLD is operable to communicate with the AP MLD using the NSTR link pair, and wherein the non-AP MLD does not transmit to the AP MLD on the NSTR link pair when the group addressed frame is scheduled to be transmitted and received by the non-AP MLD on the wireless link of the NSTR link pair without changing wireless links.
16. The method of claim 15 , wherein the scheduling information comprises a broadcast target wake time (TWT) element, and wherein the scheduling further comprises preventing channel access during a TWT service period indicated by the broadcast TWT element.
17. The method of claim 16 , wherein the broadcast TWT element comprises a Broadcast TWT Recommendation subfield equal to 0 and a Broadcast TWT ID equal to 0.
18. The method of claim 15 , further comprising assigning a first association ID (AID) to the wireless link and a second AID to a second wireless link of the NSTR link pair, wherein the first and second AID indicate if broadcast data is buffered on a respective link.
19. The method of claim 18 , wherein the AID is carried in a virtual bitmap of a Traffic indication map (TIM) information element.
20. The method of claim 15 , wherein the scheduling a group addressed frame comprises scheduling the group addressed frame to substantially prevent in-device coexistence (IDC) interference on NSTR link pair.
21. An access point (AP) multi-link device (MLD) for transmitting a group addressed frame in a wireless network, the AP MLD comprising:
a transceiver configured to send and receive data over the wireless network; and
a processor operable to:
determine that a first non-AP MLD is wirelessly transmitting over a first wireless link of a non-simultaneous transmit and receive (NSTR) link pair;
wirelessly transmit an individually addressed frame to a second non-AP MLD over a second wireless link of the NSTR link pair; and
wirelessly transmit a group addressed frame to be received by the second non-AP MLD over the second wireless link after the first non-AP MLD is done transmitting, wherein the first non-AP MLD and second non-AP MLD refrain from transmitting on the NSTR link pair during transmission of the group addressed frame without changing wireless links.
22. The AP MLD of claim 21 , wherein the wirelessly transmit the individually addressed frame does not solicit an immediate response from the second non-AP MLD when reception of the immediate response would overlap with the transmitting the group addressed frame.
23. The AP MLD of claim 21 , wherein the NSTR link pair comprises: a 5 GHz wireless link; and a 6 GHz wireless link.