Restricted TWT with enhanced multi-link single radio (EMLSR) operation
A non-access point (AP) MLD comprises STAs, each comprising a transceiver that forms a link with a corresponding AP of an AP MLD, and a processor. A restricted TWT (R-TWT) schedule is established on a first link, and a first STA on that link is a member of an R-TWT service period (SP) on that link. A second STA on a second link is not a member of any R-TWT SP on that link that overlaps with the R-TWT SP on the first link. The processor transitions the non-AP MLD into EMLSR operation wherein the first and second links form an EMLSR link pair, determines that a transmission opportunity (TXOP) has begun on the second link, and coordinates between the STAs such that a frame exchange sequence with the AP MLD on the second link during the TXOP does not overlap with the R-TWT SP on the first link.
1. A non-access point (AP) multi-link device (MLD) associated with a wireless network, the non-AP MLD comprising:
a first non-AP station (STA) affiliated with the non-AP MLD, the first non-AP STA operating on a first link with a first AP affiliated with an AP MLD, wherein a restricted target wake time (R-TWT) schedule is established on the first link;
a second non-AP STA affiliated with the non-AP MLD, the second non-AP STA operating on a second link with a second AP affiliated with the AP MLD, where a frame exchange takes place on the second link during a transmission opportunity (TXOP); and
a processor coupled to the first non-AP STA and the second non-AP STA, the processor configured to:
operate with the AP MLD in an enhanced multi-link single radio (EMLSR) mode on the first link and the second link, and
coordinate between the second non-AP STA and the second AP such that the TXOP on the second link ends no later than a threshold amount of time before a R-TWT service period (SP) starts on the first link.
2. The non-AP MLD of claim 1 , wherein the first non-AP STA is a member of the R-TWT SP on the first link, and the second non-AP STA is not a member of any R-TWT SP on the second link that overlaps with the R-TWT SP on the first link.
3. The non-AP MLD of claim 1 , wherein the processor is configured to coordinate between the second non-AP STA and the second AP such that the second non-AP STA ends the TXOP on the second link no later than the threshold amount of time before the R-TWT SP starts on the first link if the second non-AP STA is a TXOP holder on the second link.
4. The non-AP MLD of claim 1 , wherein the processor is configured to coordinate between the second non-AP STA and the second AP such that the second AP ends the TXOP on the second link no later than the threshold amount of time before a R-TWT SP starts on the first link if the second AP is a TXOP holder on the second link.
5. The non-AP MLD of claim 1 , wherein the threshold amount of time is equal to a EMLSR transition delay that is indicated in a EMLSR Transition Delay subfield in the EML Capabilities subfield of the Basic Multi-Link element.
6. The non-AP MLD of claim 1 , wherein the threshold amount of time is equal to a time required by the non-AP MLD for switching from exchanging frames on the second link to a EMLSR listening mode on the first link.
7. The non-AP MLD of claim 1 , wherein the R-TWT SP on the first link overlaps in time with frame exchange sequence to take place on the second link.
8. The non-AP MLD of claim 1 , wherein the processor is configured to coordinate between the second non-AP STA and the second AP such that frame exchange continues on the second link if a set of traffic identifiers (TIDs) negotiated for the R-TWT SP on the first link are mapped on the second link for the frame exchange.
9. The non-AP MLD of claim 1 , wherein the first link and the second link forms a pair of EMLSR link.
10. An access point (AP) multi-link device (MLD) associated with a wireless network, the AP MLD comprising:
a first AP affiliated with the AP MLD, the first AP operating on a first link with a first non-AP station (STA) affiliated with a non-AP MLD, wherein a restricted target wake time (R-TWT) schedule is established on the first link;
a second AP affiliated with the AP MLD, the second AP operating on a second link with a second non-AP STA affiliated with the non-AP MLD, wherein a frame exchange takes place on the second link during a transmission opportunity (TXOP); and
a processor coupled to the first AP and the second AP, the processor configured to:
operate with the non-AP MLD in an enhanced multi-link single radio (EMLSR) mode on the first link and the second link, and
coordinate between the second AP and the second non-AP STA such that the TXOP on the second link ends no later than a threshold amount of time before a R-TWT service period (SP) starts on the first link.
11. The AP MLD of claim 10 , wherein the first non-AP STA is a member of the R-TWT SP on the first link, and the second non-AP STA is not a member of any R-TWT SP on the second link that overlaps with the first SP.
12. The AP MLD of claim 10 , wherein the processor is configured to coordinate between the second AP and the second non-AP STA such that the second AP ends the TXOP on the second link no later than a threshold amount of time before a R-TWT SP starts on the first link if the second AP is a TXOP holder on the second link.
13. The AP MLD of claim 10 , wherein the threshold amount of time is equal to a EMLSR transition delay that is indicated in a EMLSR Transition Delay subfield in the EML Capabilities subfield of the Basic Multi-Link element.
14. The AP MLD of claim 10 , wherein the threshold amount of time is equal to a time required by the non-AP MLD for switching from exchanging frames on the second link to a EMLSR listening mode on the first link.
15. The AP MLD of claim 10 , wherein the processor is configured to coordinate between the second AP and the second non-AP STA such that frame exchange continues on the second link if a set of traffic identifiers (TIDs) negotiated for the R-TWT SP on the first link are mapped on the second link for the frame exchange.
16. A method for a non-access point (AP) multi-link device (MLD) associated with a wireless network, the method comprising:
operating with an AP MLD in an enhanced multi-link single radio (EMLSR) mode on the first link and the second link, the first link being set up between a first non-AP station (STA) affiliated with the non-AP MLD and a first AP affiliated with the AP MLD, the second link being set up between a second non-AP STA affiliated with the non-AP MLD and a second AP affiliated with the AP MLD; and
coordinating between the second non-AP STA and the second AP such that a transmission opportunity (TXOP) on the second link ends no later than a threshold amount of time before a restricted target wake time (R-TWT) service period (SP) starts on the first link, wherein the first non-AP STA is a member of the R-TWT SP on the first link, and a frame exchange takes place on the second link during the TXOP.
17. The method of claim 16 , wherein the second non-AP STA ends the TXOP on the second link no later than the threshold amount of time before the R-TWT SP starts on the first link if the second non-AP STA is a TXOP holder on the second link.
18. The method of claim 16 , wherein the threshold amount of time is equal to a time required by the non-AP MLD for switching from exchanging frames on the second link to a EMLSR listening mode on the first link.
19. The method of claim 16 , further comprising:
coordinating between the second non-AP STA and the second AP such that the frame exchange continues on the second link if a set of traffic identifiers (TIDs) negotiated for the R-TWT SP on the first link are mapped on the second link for the frame exchange.
20. The method of claim 16 , wherein the R-TWT SP on the first link overlaps in time with frame exchange sequence to take place on the second link.