Multi-link error recovery

An access point (AP) multi-link device (MLD) in a wireless LAN system, comprising:

• at least one processor;
• and
• at least one computer memory operatively connected to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
• receiving, by a first AP affiliated with the AP MLD, an Association Request frame from a first non-access point (non-AP) station (STA) affiliated with a non-AP MLD, wherein the first AP operates on a first link, wherein a second non-AP STA operating on a second link is affiliated with the non-AP MLD, wherein the Association Request frame includes a first information field related to whether the first link and the second link form a non-simultaneous transmit and receive (NSTR) link pair in the non-AP MLD, a second information field related to at least one Traffic Identifier (TID) being mapping to at least one of the first link and the second link in the non-AP MLD, and a third information field related to a maximum number of links supported by the non-AP MLD;
• acquiring, by the first AP, a transmission opportunity (TXOP) in the first link;
• transmitting, by the first AP, a downlink physical protocol data unit (PPDU) in the first link to the first non-AP STA;
• based on the downlink PPDU not successfully received by the first non-AP STA and the first information field indicating that the first link and the second link form the NSTR link pair in the non-AP MLD, transmitting, by the first AP, a Contention-Free End (CF-End) frame to truncate the TXOP in the first link,
• wherein a time interval between the downlink PPDU and the CF-End frame is set based on a point coordination function (PCF) interframe space (PIFS);
• and
• receiving, by a second AP affiliated with the AP MLD, an uplink PPDU in the second link from the second non-AP STA during the truncated TXOP.