Mapping of TID and link in multi-link

1. A method in a wireless local area network (WLAN) system, the method comprising:

transmitting, by a first multilink device (MLD) to a second MLD, a management frame comprising a multi-link element and a Traffic Identifier (TID)-to-link mapping element,

wherein the multi-link element includes a control field related to whether TID-to-link mapping is supported and a value of the control field is set based on whether the TID-to-link mapping is supported, and

wherein the TID-to-link mapping element includes a first link mapping information field indicating at least one link on which a frame belonging to a first TID is allowed to be transmitted, and a value of the first TID is one of zero (0) to seven (7);

transmitting, by the first MLD to the second MLD, an Add Block Acknowledgment (ADDBA) request frame indicating the first TID for which a block acknowledgment (BA) agreement is being set up; and

in response to the ADDBA request frame, receiving, by the first MLD from the second MLD, an ADDBA response frame,

wherein an BA agreement for the first TID is established between the first MLD and the second MLD based on the ADDBA request frame and the ADDBA response frame, and

wherein based on the BA agreement for the first TID, a data frame for the first TID is exchanged between the first MLD and the second MLD on any link to which the first TID is mapped.

2. The method of claim 1 , wherein the ADDBA request frame includes at least one parameter for transmitting a BA signal related to the first TID.

3. The method of claim 1 , wherein the first multilink MLD is a non-access point MLD and includes at least one non-access point station.

4. The method of claim 1 , wherein the second multilink MLD is an access point MLD and includes at least one access point station.

5. The method of claim 1 , wherein the management frame is transmitted on one of a 2.4 GHz link, a 5 GHz link, and a 6 GHz link.

6. A first multilink device (MLD) in a wireless local area network (WLAN) system, comprising:

a memory; and

a processor operatively coupled to the memory,

wherein the processor is adapted to:

transmit, to a second MLD, a management frame comprising a multi-link element and a Traffic Identifier (TID)-to-link mapping element,

wherein the multi-link element includes a control field related to whether TID-to-link mapping is supported and a value of the control field is set based on whether the TID-to-link mapping is supported, and

wherein the TID-to-link mapping element includes a first link mapping information field indicating at least one link on which a frame belonging to the first TID is allowed to be transmitted, and a value of the first TID is one of zero (0) to seven (7);

transmit, to the second MLD, an Add Block Acknowledgment (ADDBA) request frame indicating the first TID for which a block acknowledgment (BA) agreement is being set up; and

in response to the ADDBA request frame, receive, from the second MLD, an ADDBA response frame,

wherein an BA agreement for the first TID is established between the first MLD and the second MLD based on the ADDBA request frame and the ADDBA response frame, and

wherein based on the BA agreement for the first TID, a data frame for the first TID is exchanged between the first MLD and the second MLD on any link to which the first TID is mapped.

7. The first MLD of claim 6 , wherein the ADDBA request frame includes at least one parameter for transmitting a BA signal related to the first TID.

8. The first MLD of claim 6 , wherein the first multilink MLD is a non-access point MLD and includes at least one non-access point station.

9. The first MLD of claim 6 , wherein the second multilink MLD is an access point MLD and includes at least one access point station.

10. The first MLD of claim 6 , wherein the management frame is transmitted on one of a 2.4 GHz link, a 5 GHz link, and a 6 GHz link.

11. A first multilink device (MLD) in a wireless local area network (WLAN) system, comprising:

a memory; and

a processor operatively coupled to the memory,

wherein the processor is adapted to:

receive, from a second MLD, a management frame comprising a multi-link element and a Traffic Identifier (TID)-to-link mapping element,

wherein the multi-link element includes a control field related to whether TID-to-link mapping is supported and a value of the control field is set based on whether the TID-to-link mapping is supported, and

wherein the TID-to-link mapping element includes a first link mapping information field indicating at least one link on which a frame belonging to the first TID is allowed to be transmitted;

receive, from the second MLD, an Add Block Acknowledgment (ADDBA) request frame indicating the first TID for which a block acknowledgment (BA) agreement is being set up; and

in response to the ADDBA request frame, transmit, to the second MLD, an ADDBA response frame,

wherein an BA agreement for the first TID is established between the first MLD and the second MLD based on the ADDBA request frame and the ADDBA response frame, and

wherein based on the BA agreement for the first TID, a data frame for the first TID is exchanged between the first MLD and the second MLD on any link to which the first TID is mapped.

12. The first MLD of claim 11 , wherein the ADDBA request frame includes at least one parameter for transmitting a BA signal related to the first TID.

13. The first MLD of claim 11 , wherein the first multilink MLD is an access point MLD and includes at least one access point station.

14. The first MLD of claim 11 , wherein the second multilink MLD is a non-access point MLD and includes at least one non-access point station.

15. The first MLD of claim 11 , wherein the Association Request frame is transmitted on one of a 2.4 GHz link, a 5 GHz link, and a 6 GHz link.