Multi-link device and method performed therein

1. An access point multi-link device (AP MLD) comprising a plurality of APs, each of which comprises:

a wireless medium; and

processor circuitry coupled to the wireless medium and configured to:

transmit security capability indication information via the wireless medium;

receive an association request frame from a non-AP MLD via the wireless, medium wherein the non-AP MLD comprises a plurality of non-AP stations (non-AP STAs) and the association request frame is transmitted by the non-AP MLD based on security capability indication information from the plurality of APs and comprises security capability indication information of the plurality of non-AP STAs;

determine whether the security capability indication information of any of the plurality of non-AP STAs matches with the security capability indication information of the AP; and

if the security capability indication information of one of the plurality of non-AP STAs matches with the security capability information of the AP, transmit an association response frame to the non-AP MLD via the wireless medium, wherein

the security capability indication information transmitted by the AP comprises MLD-level capability indication information common to the plurality of APs and link-level capability indication information corresponding to the AP.

2. The AP MLD of claim 1 , wherein the link-level capability indication information of the plurality of APs is the same or different.

3. The AP MLD of claim 1 , wherein the security capability indication information transmitted by the AP is contained in a robust security network element (RSNE) and a robust security network extension element (RSNXE).

4. The AP MLD of claim 1 , wherein the MLD-level capability indication information transmitted by the AP is contained in a MLD robust security network element (RSNE) and a MLD robust security network extension element (RSNXE).

5. The AP MLD of claim 4 , wherein the MLD-level capability indication information comprises one or more of the following fields: Preauthentication, PTKSA replay counter, MFPR, MPFC, SPP A-MSDU capable, SPP A-MSDU Required, PBAC, Extended Key ID for Individually Addressed Frames, SAE-hash-to-element, Protected TWT Operations Support, Pairwise Cipher Suite and AKM Suite.

6. The AP MLD of claim 5 , wherein the MLD-level capability indication information comprises one or more Pairwise Cipher Suites for the non-AP MLD to choose.

7. The AP MLD of claim 5 , wherein the MLD-level capability indication information comprises one or more AKM Suites for the non-AP MLD to choose.

8. The AP MLD of claim 5 , wherein the MLD-level capability indication information comprises one or more Pairwise Cipher Suites, which are common to the plurality of APs, for the non-AP MLD to choose.

9. The AP MLD of claim 5 , wherein the MLD-level capability indication information comprises one or more AKM Suites, which are common to the plurality of APs, for the non-AP MLD to choose.

10. The AP MLD of claim 5 , wherein the link-level capability indication information comprises one or more of the following fields: Group Data Cipher Suite and Group Management Cipher Suite.

11. The AP MLD of claim 3 , wherein the MLD-level capability indication information comprises one of more of the following fields: Preauthentication, PTKSA replay counter, MFPR, MPFC, SPP A-MSDU capable, SPP A-MSDU Required, PBAC, Extended Key ID for Individually Addressed Frames, Group Data Cipher Suite, Group Management Cipher Suite, SAE-hash-to-element and Protected TWT Operations Support.

12. The AP MLD of claim 11 , wherein the link-level capability indication information comprises one or more of the following fields: Pairwise Cipher Suite and AKM Suite.

13. The AP MLD of claim 3 , wherein if the MLD-level capability indication information sent by all the plurality of APs within the AP MLD indicates that a security capability is supported, the security capability is supported by the AP MLD.

14. A non-access point multi-link device (non-AP MLD) comprising a plurality of non-AP stations (non-AP STAs), each of which comprises:

a wireless medium; and

processor circuitry coupled to the wireless medium and configured to:

transmit an association request frame to a AP MLD via the wireless medium, wherein

the AP MLD comprises a plurality of Access Points (APs),

the association request frame is transmitted by the non-AP MLD based on security capability indication information from the plurality of APs and comprises security capability indication information of the non-AP MLD, and

the security capability indication information of the non-AP MLD comprises MLD-level capability indication information common to the plurality of non-AP STAs and link-level capability indication information corresponding to respective ones of the plurality of non-AP STAs; and

receive an association response frame from the AP MLD via the wireless medium, wherein the association response frame is transmitted by the AP MLD if the security capability indication information of the non-AP STA matches with the security capability information of one of the plurality of APs.

15. The non-AP MLD of claim 14 , wherein the security capability indication information of the non-AP MLD is contained in a MLD robust security network element (RSNE) and a MLD robust security network extension element (RSNXE) or in a RSNE and a RSNXE.

16. The non-AP MLD of claim 15 , wherein the MLD-level capability indication information of the non-AP MLD comprises one or more of the following fields: Preauthentication, PTKSA replay counter, MFPR, MPFC, SPP A-MSDU capable, SPP A-MSDU Required, PBAC, Extended Key ID for Individually Addressed Frames, SAE-hash-to-element, Protected TWT Operations Support, and AKM Cipher Suite.

17. The non-AP MLD of claim 15 , wherein the link-level capability indication information of the non-AP MLD comprises one or more of the following fields: Group Data Cipher Suite and Group Management Cipher Suite.

18. The non-AP MLD of claim 17 , wherein if the security capability indication information from the plurality of APs comprises different Group Data Cipher Suites for the plurality of APs, the security capability indication information of the non-AP MLD does not comprise a Group Data Cipher Suite or comprises a reserved value to indicate that the non-AP MLD supports a different Group Data Cipher Suite in each link.

19. The non-AP MLD of claim 17 , wherein if the security capability indication information of the plurality of APs comprises different Group Management Cipher Suites for the plurality of APs, the security capability indication information of the non-AP MLD does not comprise a Group Management Cipher Suite or comprises a reserved value to indicate that the non-AP MLD supports a different Group Management Cipher Suite field in each link.

20. A method performed in an access point multi-link device (AP MLD), wherein the AP MLD comprises a plurality of Access Points (APs) and the method is performed by each of the plurality of APs, the method comprising:

transmitting security capability indication information via a wireless medium;

receiving an association request frame from a non-AP MLD via the wireless medium, wherein the non-AP MLD comprises a plurality of non-AP stations (non-AP STAs) and the association request frame is transmitted by the non-AP MLD based on security capability indication information from the plurality of APs and comprises security capability indication information of the plurality of non-AP STAs;

determining whether the security capability indication information of any of the plurality of non-AP STAs matches with the security capability indication information of the AP; and

if the security capability indication information of one of the plurality of non-STAs matches with the security capability information of the AP, transmitting an association response frame to the non-AP MLD via the wireless medium, wherein

the security capability indication information transmitted by the AP comprises MLD-level capability indication information common to the plurality of APs and link-level capability indication information corresponding to the AP.

21. The method of claim 20 , wherein the link-level capability indication information of the plurality of APs is the same or different.

22. The method of claim 20 , wherein the security capability indication information transmitted by the AP is contained in a robust security network element (RSNE) and a robust security network extension element (RSNXE).

23. The method of claim 20 , wherein the MLD-level capability indication information transmitted by the AP is contained in a MLD robust security network element (RSNE) and a MLD robust security network extension element (RSNXE).

24. The method of claim 23 , wherein the MLD-level capability indication information comprises one or more of the following fields: Preauthentication, PTKSA replay counter, MFPR, MPFC, SPP A-MSDU capable, SPP A-MSDU Required, PBAC, Extended Key ID for Individually Addressed Frames, SAE-hash-to-element, Protected TWT Operations Support, Pairwise Cipher Suite and AKM Suite.

25. The method of claim 24 , wherein the MLD-level capability indication information comprises one or more Pairwise Cipher Suites for the non-AP MLD to choose.