Techniques for performing multi-link communication in wireless local area network system

1. A method performed in a multi-link device (MLD) operating in a first link and second link of a wireless local area network (WLAN) system, the method comprising:

performing an association process;

obtaining a first identifier (ID) for the first link and a second ID for the second link, based on the association process,

wherein the first ID for the first link has a length of 4 bits, and the second ID for the second link has a length of 4 bits;

identifying data buffered in the MLD;

identifying a first station (STA) operating in an awake state out of the first STA related to the first link and a second STA related to the second link, which are included in the MLD; and

transmitting information on the data buffered in the MLD through the first STA,

wherein the information on the data buffered in the MLD includes a first information field related to the first STA and a second information field related to the second STA,

wherein the first information field includes the first ID for the first link and information on a queue buffered in the first STA, and

wherein the second information field includes the second ID for the second link and information on a queue buffered in the second STA.

2. The method of claim 1 , further comprising receiving a frame which requests for the information on the data buffered in the MLD.

3. The method of claim 1 , wherein the MLD operates in a power save (PS) mode.

4. The method of claim 3 , wherein the second STA operates in a doze state.

5. The method of claim 1 , wherein the information on the data buffered in the MLD is transmitted through a buffer status report (BSR) frame.

6. The method of claim 5 , wherein the information on the queue buffered in the first STA includes information on an access category indicator (ACI), information on a data traffic identifier (TID), information on a scaling factor, and information on a queue size.

7. The method of claim 1 ,

wherein the first link operates as an anchor link, and

wherein the second link operates as a non-anchor link.

8. The method of claim 1 ,

wherein the first link is included in one of 2.4 GHz, 5 GHz, and 6 GHz bands, and wherein the second link is included in one of the 2.4 GHz, 5 GHz, and 6 GHz bands.

9. A method performed in an access point (AP) multi-link device (MLD) operating in a first link and second link of a wireless local area network (WLAN) system, the method comprising:

performing an association process;

transmitting a first identifier (ID) for the first link and a second ID for the second link, based on the association process,

wherein the first ID for the first link has a length of 4 bits, and the second ID for the second link has a length of 4 bits;

transmitting a frame which requests for information on data buffered in the MLD; and

receiving the information on the data buffered in the MLD through a first AP related to the first link,

wherein the information on the data buffered in the MLD includes a first information field related to a first STA included in the MLD and a second information field related to a second STA included in the MLD,

wherein the first information field includes the first ID for the first link and information on a queue buffered in the first STA, and

wherein the second information field includes the second ID for the second link and information on a queue buffered in the second STA.

10. A multi-link device (MLD) operating in a first link and second link of a wireless local area network (WLAN) system, the MLD comprising:

a first station (STA) related to the first link;

a second STA related to the second link; and

a processor coupled to the first STA and second STA, wherein the processor is configured to:

perform an association process;

obtain a first identifier (ID) for the first link and a second ID for the second link, based on the association process,

wherein the first ID for the first link has a length of 4 bits, and the second ID for the second link has a length of 4 bits;

identify data buffered in the MLD;

identify the first STA operating in an awake state out of the first STA and second STA included in the MLD; and

transmit information on the data buffered in the MLD through the first STA,

wherein the information on the data buffered in the MLD includes a first information field related to the first STA and a second information field related to the second STA,

wherein the first information field includes the first ID for the first link and information on a queue buffered in the first STA, and

wherein the second information field includes the second ID for the second link and information on a queue buffered in the second STA.

11. The MLD of claim 10 , wherein the processor is further configured to receive a frame which requests for the information on the data buffered in the MLD.

12. The MLD of claim 10 , wherein the information on the data buffered in the MLD is transmitted through a buffer status report (BSR) frame.

13. The MLD of claim 12 , wherein the information on the queue buffered in the first STA includes information on an access category indicator (ACI), information on a data traffic identifier (TID), information on a scaling factor, and information on a queue size.

14. The MLD of claim 10 ,

wherein the first link operates as an anchor link, and

wherein the second link operates as a non-anchor link.

15. An access point (AP) multi-link device (MLD) operating in a first link and second link of a wireless local area network (WLAN) system, the AP MLD comprising:

a first AP related to the first link;

a second AP related to the second link; and

a processor coupled to the first AP and second AP, wherein the processor is configured to:

perform an association process;

transmit a first identifier (ID) for the first link and a second ID for the second link, based on the association process,

wherein the first ID for the first link has a length of 4 bits, and the second ID for the second link has a length of 4 bits;

transmit a frame which requests for information on data buffered in the MLD; and

receive the information on the data buffered in the MLD through a first AP related to the first link,

wherein the information on the data buffered in the MLD includes a first information field related to a first STA included in the MLD and a second information field related to a second STA included in the MLD,

wherein the first information field includes the first ID for the first link and information on a queue buffered in the first STA, and

wherein the second information field includes the second ID for the second link and information on a queue buffered in the second STA.

16. An apparatus used in a wireless local area network (WLAN) system, the apparatus comprising:

a processor; and

a memory coupled to the processor,

wherein the processor is configured to:

perform an association process;

obtain a first identifier (ID) for the first link and a second ID for the second link, based on the association process,

wherein the first ID for the first link has a length of 4 bits, and the second ID for the second link has a length of 4 bits;

identify data buffered in a multi-link device (MLD);

identify a first station (STA) operating in an awake state out of the first STA related to the first link and a second STA related to the second link, which are included in the MLD; and

transmit information on the data buffered in the MLD through the first STA,

wherein the information on the data buffered in the MLD includes a first information field related to the first STA and a second information field related to the second STA,

wherein the first information field includes the first ID for the first link and information on a queue buffered in the first STA, and

wherein the second information field includes the second ID for the second link and information on a queue buffered in the second STA.