Off-channel TDLS communications for multi-link devices

Abstract

The non-AP MLD (120) obtains a link ID defining an off-link corresponding to at least one off-channel (172b) that does not overlap with the channel (s) used by the AP device. The non-AP MLD (120) uses the link ID as an indication of an off-link for the TDLS direct link to establish the TDLS direct link between a first TDLS STA (122) affiliated to the non-AP MLD (120) and a second TDLS STA (132) affiliated to a second non-AP MLD (130) over the channel (s) used by the AP device. The non-AP MLD (120) operates a point-to-point communication between the first TDLS STA and the second TDLS STA on the off-link.

Description

Technical Field

[0001] The present invention relates generally to wireless communications, and more particularly to point-to-point (P2P) communications over a multi-link (ML) arrangement. Background Art

[0002] Wireless communication networks are widely deployed to provide various communication services, such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple access networks include code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, and single carrier FDMA (SC-FDMA) networks.

[0003] The 802.11 family of standards adopted by the Institute of Electrical and Electronics Engineers (IEEE-RTM) provides a number of mechanisms for wireless communications between STAs.

[0004] With the development of latency-sensitive applications (such as online games, real-time video streaming, virtual reality, remote control of drones or robots), better throughput, low latency and robustness requirements and issues need to be considered. Currently, the IEEE802.11 working group is considering this problematic issue as the main goal of releasing the next major 802.11 version (called 802.11be or "extremely high throughput" EHT).

[0005] IEEE P802.11be / D2.2 version (October 2022, under the "D2.2 standard") introduced Multi-Link Operation (MLO). MLO improves data throughput by allowing STAs to communicate on multiple concurrent and non-continuous communication links.

[0006] MLO enables a non-AP (Access Point) MLD (ML device) to register with an AP MLD, i.e., discover, authenticate, associate, and set up multiple communication links with the AP MLD. Each communication link so set up (hereinafter "setup link" or "enable link" once enabled) enables channel access and frame exchange between the non-AP MLD and the AP MLD based on the support capabilities exchanged during the association process.

[0007] MLD is a logical entity with more than one subordinate station (STA) and a single medium access control (MAC) service access point (SAP) for a logical link control (LLC), which includes one MAC data service. Therefore, an AP MLD consists of multiple subordinate APs, while a non-AP MLD consists of multiple subordinate non-AP STAs. The subordinate STAs in both AP MLD and non-AP-MLD can communicate with the subordinate STAs of another MLD through each of the multiple communication links set up using the 802.11 mechanism.

[0008] The existing Tunneled Direct Link Setup (TDLS) has been adapted to coexist with the MLD of the D2.2 standard. More precisely, the D2.2 standard adapts the TDLS mechanism to the multi-link feature by adjusting the signaling of the MAC address in the setup frame when establishing a TDLS session on one of the multiple setup links. As a result, a direct link consisting of a single communication link (e.g., a 20MHz channel on any one of the 2.4, 5, and 6GHz frequency bands) is established between two wireless STAs (TDLS peer STAs), each of which is attached to the MLD.

[0009] Previously recognized by the IEEE 802.11z standard in 2008, TDLS enables devices (called TDLS peer STAs) to link directly to each other when connected to a conventional AP. In order to set up and maintain a direct link, the two TDLS peer STAs should be associated with the same infrastructure BSS (in short, the same AP). The TDLS mechanism provides a setup frame that is encapsulated in a data frame and exchanged between two TDLS peer STAs. This allows the setup frame to be transmitted transparently (or "tunneled") through the AP. The setup frame includes a so-called TDLS action frame. In addition, since the setup frame is transmitted transparently through the AP, the AP does not need to be TDLS-aware or have the same capabilities as the TDLS peer STAs involved in TDLS-based point-to-point communications. Then, once the direct link is set up, the TDLS peer STAs can communicate directly with each other through the set direct link without involving the AP (although these STAs remain associated with the AP). It must be noted that when TDLS peer STAs communicate directly via a direct link, P2P traffic competes with other traffic to / from the AP because P2P traffic and other traffic to / from the AP are conducted on the same communication link (ie, the same frequency channel).

[0010] In order to reduce competition with traffic involving the AP, switching between such a channel used by the AP, called the "fundamental channel", and an associated off-channel has been proposed. This mechanism is known as "TDLS channel switching".

[0011] IEEE P802.11-REVme / D2.0 version (October 2022) defines an off-channel. An off-channel is a channel used by a TDLS peer STA that does not overlap with the (one or more) channels used by the AP associated with the TDLS peer STA. In other words, an off-channel is a channel that does not belong to the (one or more) operating channels of the AP and can be used for P2P communication. The TDLS device can negotiate to move (i.e., switch) from the basic channel (i.e., shared with the AP and used to set up the TDLS direct link) to such an off-channel (not shared with the AP). The two TDLS devices previously advertised in the TDLS setup frame (usually a request and a response) that they at least partially support (one or more) the same channel including (one or more) off-channels. Before moving (switching) from the basic channel to the off-channel, the TDLS device is in PS (power save) mode with the AP and is not involved in the active service period with the AP.

[0012] When operating via an off-channel, the TDLS device remains in power saving mode in the primary channel and can no longer communicate with the AP. Therefore, the TDLS device must regularly and therefore repeatedly return to the primary channel to perform actions such as receiving beacons, checking the TIM (Traffic Indication Map) for any buffered packets, and communicating with other devices in the network.

[0013] As defined in the P802.11-REVme / D2.0 version, despite the great interest in improving the coexistence between infrastructure and P2P communications, the use of off-channels follows the traditional behavior, which requires repeated TDLS channel switching (i.e. switching back and forth between the base channel and the off-channel). This is of course not optimal, because due to repeated TDLS channel switching, the TDLS device (TDLS peer STA) cannot persistently use the off-channel for TDLS (P2P) transmission.

[0014] Therefore, there is a need to improve off-channel usage mechanisms in the context of multi-link (multi-radio) mechanisms. Summary of the invention

[0015] A broad object of the present invention is to overcome some of the aforementioned problems.

[0016] The inventors have noticed that the above-mentioned drawbacks come from the fact that although non-AP MLDs have multi-link (multi-radio) capabilities, they cannot persistently use the off-channel for TDLS transmissions while maintaining the channel used for communication with the AP (i.e., remaining active on the channel) to, for example, obtain beacon frames. Therefore, the present invention defines a new mechanism that allows non-AP MLDs to persistently use the off-channel for TDLS transmissions, thereby eliminating the need for repeated switching between the off-channel and the base channel.

[0017] In this context, an embodiment of the present invention relates to a method of communication in a wireless network, comprising: at a non-access point multi-link device (non-AP MLD) associated with an access point (AP) device:

[0018] obtaining a link identifier (ID) defining an off-link corresponding to at least one off-channel that does not overlap with a channel(s) used by the AP device;

[0019] Using the link ID as an indication of the off-link for a tunneled direct link setup (TDLS) direct link, establishing the TDLS direct link between a first TDLS station (STA) attached to the non-AP MLD and a second TDLS STA attached to another non-AP MLD over the channel(s) used by the AP device; and

[0020] Point-to-point communication between the first TDLS STA and the second TDLS STA is operated on the off-link.

[0021] Therefore, a new link ID is proposed, which is independent of the basic channel and the link setup with the AP device to define a new link called "off-link". Using this new link ID to establish a TDLS direct link can be performed as detailed below:

[0022] Directly, i.e., directly using the link ID to define the off-link as a TDLS direct link (in this case there is no channel switching);

[0023] Or indirectly, i.e. through a two-step mechanism comprising: setting up an initial TDLS direct link (in a conventional manner) and then performing a channel switch using the channel of the off-link as the target channel for the target link, or performing a link switch using the link ID to define the off-link as the target link for the link switch.

[0024] In both cases, the off-channel is defined as a self-link (i.e., a new off-link) by using a new link ID independent of the base channel (defining the link that establishes a conventional TDLS direct link). In fact, in the first case, there is no base channel, because there is no channel switch. In the second case, once the switch is performed, there is no dependency on the base channel. It should be noted that, as described below, in the second case, the initial TDLS direct link (operating on the base channel) can even be removed or disabled.

[0025] Therefore, the non-AP MLD no longer has to perform any channel switching from the off-channel back to the base channel to receive the beacon frame.It turns out that the non-AP MLD can persistently use the off-link (and correspondingly one or more off-channels) for TDLS transmission.

[0026] Furthermore, even when the first TDLS STA of the non-AP MLD is operating via an off-link, if necessary and due to the multi-link feature, the non-AP MLD can communicate with the AP via any other link that may be established by another of its affiliated STAs with any affiliated AP. Thus, the non-AP MLD can receive beacons, check TIMs for any buffered packets, and communicate with other devices in the network without repeated channel switching.

[0027] In other words, the proposed solution exploits the multi-link (multi-radio) capability of non-AP MLDs to establish persistent TDLS direct links on one or more off-channels due to autonomous off-links (i.e., independent of the base channel) while maintaining communication with the AP device through another link.

[0028] Optional features of the invention are defined below with reference to methods, whilst these features may be converted into apparatus features.

[0029] Advantageously, the method further comprises operating a communication with the AP device over another link corresponding to at least one of said channel(s) used by the AP device.

[0030] As already discussed above, if necessary, the non-AP MLD can communicate with the AP via another link established by another of its subordinate STAs. Therefore, the non-AP MLD does not have to perform any channel switching to receive beacons, check TIMs for any buffered packets, and communicate with other devices in the network.

[0031] In some implementations, obtaining the link ID includes receiving information about a virtual AP attached to the AP MLD from an AP device as the AP MLD, the virtual AP defining the off-link and being assigned the link ID, the virtual AP not communicating in its basic service set (BSS).

[0032] A "virtual AP" refers to an adjunct AP that is not actually operating (it does not communicate). Such a virtual AP advantageously gives a link identifier for a link corresponding to an off-channel to a non-APMLD.

[0033] In these implementations, the link ID is created by the AP MLD by creating a virtual AP, which is a new type of AP that is not used for communication between non-AP STAs or MLDs and the AP MLD.

[0034] In some other implementations, establishing, by the non-AP MLD, the TDLS direct link includes defining an off-link and a link ID based on information about at least one off-channel received from the AP device.

[0035] In these other implementations, the link ID is created by the non-AP MLD and other non-AP STAs or MLDs (without involving the AP MLD).

[0036] In some implementations, establishing the TDLS direct link includes: defining the off-link as a TDLS direct link using the link ID to set up the TDLS direct link.

[0037] As discussed above, in this first case, establishing the TDLS direct link using the new link ID is performed directly, ie, directly using the link ID to define the off-link as a TDLS direct link (no channel switching in this case). The corresponding advantages have been discussed above.

[0038] In some other implementations, establishing a TDLS direct link includes:

[0039] Setting an initial TDLS direct link that enables point-to-point communication between the first TDLS STA and the second TDLS STA; and

[0040] Channel switching is performed to move point-to-point communication from an initial TDLS direct link to a target link using a channel of an off-link as a target channel for a target link or defining an off-link as a target link using a link ID.

[0041] As discussed above, in this second case, establishing the TDLS direct link using the new link ID is performed indirectly (ie, by a two-step mechanism involving setting up the initial TDLS direct link followed by a channel switch). The corresponding advantages have been discussed above.

[0042] In various embodiments, the method further includes: at the non-AP MLD: disabling the initial TDLS direct link or removing the initial TDLS direct link.

[0043] Thus, the channel(s) corresponding to the removed or disabled links may be reused and the network resources are thereby optimized.

[0044] An embodiment of the present invention further provides a communication method in a wireless network, comprising: at a non-AP MLD associated with an access point multi-link device (AP MLD),

[0045] receiving from the AP MLD information about a virtual AP attached to the AP MLD, the virtual AP not communicating in its basic service set (BSS), the virtual AP defining an off-link corresponding to at least one off-channel that does not overlap with the channel (one or more than one) used by the AP MLD, the attached virtual AP being assigned a link identifier (link ID) to identify the off-link; and

[0046] Communicating over the wireless network using the link ID.

[0047] Therefore, the non-AP MLD receives a new type of information (information about a virtual AP which is a new type of AP not used for communication between the non-AP STA or MLD and the AP MLD) and in particular a specific link ID enabling the non-AP MLD to communicate on the wireless network.

[0048] This configuration advantageously allows defining links in addition to the link operated by the AP MLD. Such additional links may, for example, be used for direct communications within the wireless network.

[0049] In some embodiments, the fact that a virtual AP does not communicate in its BSS does not prevent the present solution from being applied in a multi-AP context, ie, multi-AP communication using off-channels (and off-links).

[0050] In various embodiments, communicating over the wireless network using the link ID includes:

[0051] Using the link ID as an indication of an off-link of a tunneled direct link setup (TDLS) direct link, establishing the TDLS direct link between a first TDLS station (STA) attached to the non-AP MLD and a second TDLS STA through the channel(s) used by the AP device; and

[0052] Point-to-point communication between the first TDLS STA and the second TDLS STA is operated on the off-link.

[0053] Therefore, based on the information received about the virtual AP, the above mechanism is compatible with the TDLS mechanism and allows the non-AP MLD to persistently use the off-link (and corresponding at least one off-channel) for TDLS transmission. In fact, even when the first TDLS STA of the non-AP MLD is operating via the off-link (corresponding to at least one off-channel), the non-AP MLD can communicate with the AP via another link established by another STA among the STAs to which it belongs, if necessary. Therefore, the non-AP MLD does not have to perform any channel switching to receive beacons, check TIMs for any buffered packets, and communicate with other devices in the network.

[0054] In various embodiments, establishing the TDLS direct link comprises at least one of the following operations:

[0055] including, in a TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA, a link identifier corresponding to the virtual AP and thus corresponding to the off-link, the link identifier including a basic service set identifier (BSSID) field having a BSSID;

[0056] adding the off-link in a per-STA profile sub-element carried in a TDLS multilink element exchanged between the first TDLS STA and the second TDLS STA; and

[0057] A multilink link information element including a link ID bitmap indicating the off-link is included in the TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA.

[0058] Each of these operations advantageously limits overhead while reusing and / or slightly modifying existing elements and / or frames.

[0059] An embodiment of the present invention further provides a communication method in a wireless network, comprising: at an access point multi-link device (AP MLD),

[0060] Instantiating an auxiliary virtual AP, the auxiliary virtual AP defining an off-link corresponding to at least one off-channel that does not overlap with the channel(s) used by the AP MLD, the auxiliary virtual AP being assigned a link identifier, i.e., a link ID, to identify the off-link, the virtual AP not communicating in its basic service set, i.e., a BSS; and

[0061] Information about the affiliated virtual AP defining the off-link is transmitted to a non-AP MLD, the information including the link ID.

[0062] The advantages of using virtual APs to define off-links have been discussed above.

[0063] In various embodiments, the method further comprises: receiving a trigger for instantiation of the subordinate virtual AP, wherein the trigger belongs to the group consisting of:

[0064] In a case where the non-AP MLD has not yet associated with the AP MLD, receiving a probe request frame from the non-AP MLD, the probe request frame including an off-link capability and / or a channel usage element as a new input in the extended capability;

[0065] In a case where the non-AP MLD is associated with the AP MLD, receiving a channel usage request frame from the non-AP MLD, the channel usage request frame including a channel usage element requesting setup of the off-link;

[0066] receiving quality of service characteristics, ie, QoS characteristics; and

[0067] Detect triggering inside the AP MLD.

[0068] In some implementations, in addition to the link ID, the information about the subordinate virtual AP also includes one or more parameters belonging to the group consisting of:

[0069] Operation class;

[0070] Channel number;

[0071] The channel width used to define the operating frequency band;

[0072] BSSID;

[0073] BSSID-related information indicating that the virtual AP is unreachable (e.g., from the AP reachability field of the BSSID information element such as defined in IEEE P802.11-REVme / D1.3); and

[0074] Non-inherited elements.

[0075] In some embodiments, a specific value from the AP reachability field of the BSSID information element (eg, such as defined in IEEE P802.11-REVme / D1.3) can be used to distinguish the virtual AP from APs that can communicate.

[0076] This advantageously limits overhead while reusing the existing AP reachability field.

[0077] In various embodiments, information about the affiliated virtual APs is exchanged at least in part as part of a multilink element in a probe response frame or in a beacon frame or in an association response frame, and:

[0078] The subordinate virtual AP is declared as an additional STA in the multi-link element with a dedicated per-STA profile sub-element containing information for distinguishing the subordinate virtual AP from other subordinate APs of the AP MLD; or

[0079] The common information field of the multi-link element includes an off-link bitmap or a virtual AP bitmap subfield.

[0080] Each of these configurations advantageously limits overhead while reusing and / or slightly modifying existing elements and / or frames.

[0081] In various embodiments, the per-STA profile sub-element specific to the subordinate virtual AP:

[0082] including a non-inherited element that carries at least one of AP capabilities and operations that are not useful to a virtual AP that is not communicating in its basic service set (BSS) and should not be inherited by the virtual AP from a reporting STA; or

[0083] Not subject to inheritance.

[0084] This avoids unnecessary inheritance.

[0085] In various embodiments, the information about the affiliated virtual AP is at least partially exchanged as part of a neighbor report element or a simplified neighbor report element included in a beacon frame, the part being an off-link field or a usage mode field included in an MLD parameter subfield, and giving information related to a link corresponding to the content of a link ID field also included in the MLD parameter subfield.

[0086] Each of these configurations advantageously limits overhead while reusing and / or slightly modifying existing elements and / or frames.

[0087] In various embodiments, the information about the subordinate virtual AP includes information about the at least one off-channel of the AP MLD exchanged as a channel usage element,

[0088] -The channel usage elements include:

[0089] a Link ID Information field containing the Link ID and associated with all channel entries of the Channel Entry field; or

[0090] a link ID information subfield of a channel entry field, the link ID information subfield containing the link ID and associated with all channel entries of the channel entry field; and

[0091] - The channel usage element is included in a probe response frame or a channel usage response frame.

[0092] Each of these configurations advantageously limits overhead while reusing and / or slightly modifying existing elements and / or frames.

[0093] In some embodiments, obtaining the link ID includes: creating, by the non-AP MLD, a TDLS link with a self-link ID, the self-link ID defining an off-link corresponding to at least one off-channel that does not overlap with a channel (or more than one) used by the AP device. This implementation advantageously utilizes the MLD capabilities of the non-AP MLD involved in point-to-point communications using a connection with a legacy AP (i.e., an AP that does not support the multi-link feature).

[0094] In some specific embodiments, creating a TDLS link includes: triggering the creation of the same TDLS link at another non-AP MLD. This means that two non-AP MLDs that desire direct exchange thus simultaneously create the same off-link for this purpose. Therefore, this configuration facilitates immediate and temporary creation of an off-link for a temporary direct link session.

[0095] In some embodiments, establishing the TDLS direct link includes: establishing a TDLS direct link with the second TDLS STA with the created off-link as a target. In other words, establishing the TDLS direct link includes: setting up the TDLS direct link by defining the off-link as a TDLS direct link using a link ID.

[0096] This means that once the off-link has been created (on both sides) independently of any link setup with the AP device, the two non-AP MLDs can use the conventional TDLS direct link mechanism to setup the TDLS direct link over the off-link. This configuration fully integrates the standardized mechanism.

[0097] In some embodiments, the TDLS setup frames exchanged during the TDLS direct link establishment include a MAC address to identify the first TDLS STA of the created off-link.

[0098] As described above, in this first case, establishing the TDLS direct link using the new link ID is performed directly (ie, the link ID is directly used to define the off-link as a TDLS direct link (in this case, there is no channel switching)).

[0099] In some embodiments, creating a TDLS link includes exchanging TDLS action frames tunneled by an AP device with another non-AP MLD to simultaneously create an off-link at both non-AP MLDs. This allows the non-AP MLD to use any link set up (and enabled) with the AP device to exchange signaling frames (here, TDLS action frames) in anticipation of creating and establishing an off-link for direct communication with each other.

[0100] In a specific embodiment, exchanging TDLS action frames includes: for non-AP MLD,

[0101] sending a link setup request to create an off-link corresponding to at least one candidate off-channel that does not overlap with the channel(s) used by the AP device; and

[0102] In response thereto, a link setup response is received that includes an alternate off-link corresponding to at least one alternate off-channel that does not overlap with the channel(s) used by the AP device.

[0103] Therefore, non-AP MLD can negotiate off-link.

[0104] In some embodiments, the method further includes: establishing a first TDLS direct link between the two non-APMLDs on a first link set up with the AP device for a first TDLS session, and switching the first TDLS session to an off-link.

[0105] In some embodiments, switching the first TDLS session to the off-link includes: performing a TDLS link switch to move the first TDLS session to the off-link. The off-link has been created in the previous step. The two-step method advantageously allows only the link IDs to be handled to be switched, which can be reused later. A dedicated TDLS action frame can be used for switching.

[0106] In a specific embodiment, performing a TDLS link handover includes: exchanging TDLS action frames directly on the first TDLS direct link. This configuration utilizes the already established TDLS direct link to efficiently (quickly) move to the off-link, typically with the expectation that the already established TDLS direct link (on the first link) will be released once the handover is completed. This is intended to reduce access contention on the first link.

[0107] In some embodiments, switching the first TDLS session to the off-link includes: performing a TDLS channel switch, the TDLS channel switch targeting one or more off-channels of the off-link to move the first TDLS session to the off-link. This configuration can advantageously rely on a conventional (standardized) TDLS direct link mechanism (so-called "TDLS channel switch" in section 11.20.6 of REVme 2.0) to simultaneously disable the TDLS direct link on the first link and enable (or set up) the TDLS direct link on the off-link in the sense of the present invention.

[0108] In some embodiments, the method further includes: removing or disabling the first link set up with the AP device. This advantageously does not remove or disable the TDLS direct link on the off-link, because the TDLS direct link on the off-link is created independently of the first link. This configuration ensures that the affiliated STA of the non-AP MLD no longer needs to continue activities with the corresponding AP (e.g., such as switching back to the AP's channel).

[0109] Thus, the channel(s) corresponding to the removed or disabled links may be reused and the network resources are thereby optimized.

[0110] According to alternative embodiments, removing the first link or disabling the first link may include one of:

[0112] updating a TID-to-link mapping of a link set up with the AP device to remove all TIDs assigned to the first link; and

[0113] A multi-link setting with the AP device excluding the first link is performed.

[0114] In some embodiments, the link ID defining the off-link is selected from a set of candidate link IDs that are deprived of any link ID used by the AP device. For example, the link ID may be selected from a value higher than 15. This configuration ensures that conflicts between link IDs are avoided at non-AP MLDs.

[0115] In some embodiments, the method further comprises: in response to creating an off-link, notifying the AP device of the created off-link. One or more off-channels and possible link IDs may be notified. This allows the AP to adjust its management of the BSS, for example, by avoiding the use of off-channels that compete with the created off-link.

[0116] In some embodiments, the off-link is assigned a BSSID (Basic Service Set Identifier), which is set to the MAC address of one of the TDLS STAs or one of the two non-AP MLDs. This means that the first TDLS STA and the second TDLS STA operate on a dedicated BSS (identified by the BSSID) separated from the AP device (although other subordinate stations of the non-AP MLD can operate in the BSS managed by the AP device). This configuration advantageously allows the definition of an ad-hoc BSS without modifying existing information elements, particularly the link identifier IE.

[0117] In some embodiments, obtaining the link identifier includes obtaining recommended channels for the non-infrastructure BSS or off-channel TDLS direct link from the AP device, and selecting one or more off-channels from the recommended channels.

[0118] In some embodiments, the TDLS action frame includes a multi-link element having one or several per-STA profiles to respectively signal one or more off-channels for an off-link.

[0119] This configuration allows TDLS STA to define a multi-channel off-link using existing IE. In this case, all off-channels can be used to define the created off-link.

[0120] However, the configuration may alternatively allow a TDLS STA (e.g., a first TDLS station) to define multiple candidate channels for an off-link to be created. In this case, the responding TDLS STA may select one of the candidate channels defined in each STA configuration file (e.g., a channel that best suits the capabilities of the responding station) to form / create an off-link.

[0121] Relatedly, an embodiment of the present invention further provides a wireless communication device, which includes at least one microprocessor configured to execute any of the methods described above.

[0122] Another aspect of the present invention relates to a Tunneled Direct Link Setup (TDLS) action frame to be exchanged between two non-access point multi-link devices (non-AP MLDs) associated with an access point device, i.e., an AP device, the frame comprising:

[0123] an Action field set to a value strictly greater than 10 to indicate that the frame is a request to create a TDLS link with an Own Link ID defining an off-link corresponding to at least one off-channel that does not overlap with the channel(s) used by the AP device; and

[0124] At least one Information Element (IE) that defines the link ID and includes the at least one off-channel.

[0125] Yet another aspect of the present invention relates to a Tunneled Direct Link Setup (TDLS) action frame to be exchanged between two non-access point multi-link devices (non-AP MLDs) associated with an access point (AP) device, the frame comprising:

[0126] an Action field, which is set to a value strictly greater than 10 to indicate that the frame is a request to move a current TDLS session on a first link having a first link ID to a second link having a different second link ID; and

[0127] At least one Information Element (IE) field indicating the second link ID.

[0128] In practice, such frames may be tunneled by the AP device to another non-AP MLD.

[0129] In particular, the second link ID may identify an off-link defined on at least one off-channel that does not overlap with the channel(s) used by the AP device.

[0130] Furthermore, the at least one IE may include a BSSID field associated with the second link, the BSSID field being set to a MAC address of one of the non-AP MLDs or a MAC address of a station affiliated with one of the non-AP MLDs.

[0131] Another aspect of the present invention relates to a non-transitory computer-readable medium storing a program which, when executed by a microprocessor or a computer system in a wireless device, causes the wireless device to perform any of the methods described above.

[0132] At least a portion of the method according to the invention may be computer-implemented. Thus, the invention may take the form of a fully hardware embodiment, a fully software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which may be collectively referred to herein as "circuits," "modules," or "systems." Furthermore, the invention may take the form of a computer program product embodied in any tangible medium of expression having a computer-usable program code embodied in the medium.

[0133] Since the present invention can be implemented in software, the present invention can be embodied as computer readable code for providing to a programmable device on any suitable carrier medium. Tangible, non-transitory carrier media may include storage media such as floppy disks, CD-ROMs, hard disk drives, magnetic tape devices, or solid-state memory devices. Transient carrier media may include signals such as electrical signals, electronic signals, optical signals, acoustic signals, magnetic signals, or electromagnetic signals (e.g., microwave or RF signals).

[0134] The names of the (one or more) information elements provided in this document are intended to reflect the information elements currently used in the 802.11 standard to facilitate the reading of this document. Of course, any other naming that carries the same information may be used instead. BRIEF DESCRIPTION OF THE DRAWINGS

[0135] Embodiments of the present invention will now be described, by way of example only, and with reference to the following drawings, in which:

[0136] Figure 1 A typical 802.11 network environment involving ML transmission between MLDs is illustrated, wherein a single link tunneled direct link setup (TDLS) direct link is established;

[0137] Figure 1a and Figure 1b An exemplary 802.11be multi-link reference model for MLD (AP MLD or non-AP MLD) is illustrated;

[0138] Figure 2 A possible scenario of the discovery and association process between a non-AP MLD and an AP MLD is illustrated using the frame exchanges in the timeline;

[0139] Figure 2a The frame exchanges in the timeline are used to illustrate possible scenarios for the initiator peer non-AP STA to handle P2P traffic;

[0140] Figure 3 illustrates the format of an 802.11 action frame according to the 802.11 standard;

[0141] Figure 4a The so-called "Link Identifier" IE according to the 802.11 standard is illustrated;

[0142] Figure 4b The so-called "TDLS Multilink" IE according to the 802.11 standard is illustrated;

[0143] Figure 4c The so-called "Multi-Link Link" IE according to the 802.11 standard is illustrated;

[0144] Fig.5a1The so-called "Basic Variant Multilink" IE according to the 802.11 standard is illustrated;

[0145] Fig.5a2 The so-called "per-STA profile" sub-element according to the 802.11 standard is illustrated;

[0146] Figure 5b illustrates a revised "per-STA profile" sub-element according to an embodiment of the present invention;

[0147] Figure 6 illustrates the so-called "Channel Usage" IE according to the 802.11 standard;

[0148] Figure 6a illustrates a revised "Channel Usage" IE according to an embodiment of the present invention;

[0149] Figure 6b illustrates a revised "Channel Usage" IE according to other embodiments of the present invention;

[0150] Figure 6c A channel use request frame is illustrated;

[0151] Figure 7a The following examples illustrate how the embodiments of the present invention can be implemented. Figure 1 An 802.11 network environment involving a multi-radio device MLD;

[0152] Figure 7b The following examples illustrate how the embodiments of the present invention can be implemented. Figure 1 Another 802.11 network environment involving a multi-radio device MLD;

[0153] Figure 7c illustrates example operations for wireless communications performed by an AP MLD for instantiation of a virtual AP in accordance with certain aspects of the present invention;

[0154] Figure 7d illustrates example operations of wireless communications by a non-AP MLD for TDLS setup on an off-link in accordance with certain aspects of the present invention;

[0155] Figure 8 The frame exchanges in the use timeline illustrate when the AP MLD notifies the TDLS initiator non-AP MLD that the off-link is available to handle P2P traffic. Figure 2 and Figure 2a Scenes;

[0156] Figure 8b The frame exchanges in the usage timeline illustrate when a non-AP MLD that has been associated with an AP MLD requests the creation of an off-link for P2P traffic through a channel usage request frame. Figure 2 and Figure 2a Scenes;

[0157] Figure 8c The frame exchanges in the use timeline illustrate when a non-AP MLD that has been associated with an AP MLD performs TDLS setup on a link shared with an AP and moves off the link by using TDLS channel switching. Figure 2 and Figure 2a Scenes;

[0158] Fig. 9 Illustrate the format of the Reduced Neighbor Report (RNR) information element present in each beacon;

[0159] Figure 9a illustrates a TBTT information field (included in an RNR information element) including a revised MLD parameter field according to a specific embodiment of the present invention (by including a new off-link field);

[0160] Figure 9b illustrates a TBTT information field (included in an RNR information element) including a revised MLD parameter field according to another specific embodiment of the present invention (by including a new usage mode field);

[0161] Fig.10a shows a schematic representation of a communication device according to at least one embodiment of the present invention;

[0162] Fig.10b Schematically illustrates Fig.10a The architecture of the communication device;

[0163] Fig.11a An 802.11 network environment involving a non-AP multi-radio device MLD associated with an AP device in which embodiments of the present invention may be implemented is illustrated;

[0164] Fig.11b Using a flow chart, exemplary steps for direct communication according to certain aspects of the present invention are illustrated;

[0165] Fig.11c The creation and use of an off-link according to an embodiment of the present invention is illustrated using frame exchanges in a timeline, where channel usage information is obtained from a probe response frame;

[0166] Fig.11d The creation and use of an off-link according to other embodiments of the present invention are illustrated using frame exchanges in a timeline, where channel usage information is obtained from a channel usage response frame;

[0167] Fig.12a The embodiments of the present invention can be implemented by illustrating Figure 1Another 802.11 network environment of a multi-radio device MLD;

[0168] Figure 12b Using a flow chart, exemplary steps for direct communication according to certain aspects of the present invention are illustrated; and

[0169] Fig.12c and Fig.12d Two different scenarios for creating and using off-links according to embodiments of the present invention are illustrated using frame exchanges in a timeline. DETAILED DESCRIPTION

[0170] The technology described herein can be used in various broadband wireless communication systems, including communication systems based on orthogonal multiplexing schemes. Examples of such communication systems include space division multiple access (SDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency division multiple access (SC-FDMA) systems. SDMA systems can use sufficiently different directions to simultaneously transmit data belonging to multiple user terminals (i.e., wireless devices or STAs). TDMA systems can allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots or resource units, and each time slot is assigned to a different user terminal. OFDMA systems use orthogonal frequency division multiplexing (OFDM), which is a modulation technique that divides the entire system bandwidth into multiple orthogonal subcarriers or resource units. These subcarriers can also be referred to as frequency modulation, frequency bands, etc. With OFDM, each subcarrier can be modulated independently using data. An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on subcarriers distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on blocks of adjacent subcarriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent subcarriers.

[0171] The teachings herein may be incorporated into (e.g., implemented in or performed by) various devices (e.g., STAs). In some aspects, a wireless device or STA implemented according to the teachings herein may include an access point (so-called AP) or may not include an access point (so-called non-AP STA or STA).

[0172] Although the examples are described in the context of a WiFi (RTM) network, the invention may be used with any type of wireless network, such as a mobile phone cellular network implementing very similar mechanisms.

[0173] An AP may include, be implemented as, or be referred to as a Node B, a radio network controller (“RNC”), an evolved Node B (eNB), a 5G next-generation base STA (gNB), a base STA controller (“BSC”), a base transceiver STA (“BTS”), a base STA (“BS”), a transceiver function (“TF”), a radio router, a radio transceiver, a basic service set (“BSS”), an extended service set (“ESS”), a radio base STA (“RBS”), or some other terminology.

[0174] A non-AP STA may include, be implemented as, or be referred to as a subscriber STA, a subscriber unit, a mobile STA (MS), a remote STA, a remote terminal, a user terminal (UT), a user agent, a user device, a user equipment (UE), a user STA, or some other terminology. In some implementations, a STA may include a cellular phone, a cordless phone, a session initiation protocol ("SIP") phone, a wireless local loop ("WLL") STA, a personal digital assistant ("PDA"), a handheld device with wireless connection capabilities, or some other suitable processing device connected to a wireless modem. Thus, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or a smart phone), a computer (e.g., a laptop computer), a tablet computer, a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a global positioning system (GPS) device, or any other suitable device configured to communicate via a wireless or wired medium. In some aspects, a non-AP STA may be a wireless node. Such a wireless node may provide, for example, connectivity to or from a network (eg, a wide area network such as the Internet or a cellular network) via a wired or wireless communication link.

[0175] The AP manages a collection of STAs (STAs registered to or associated with the AP) that together organize their access to the wireless medium for communication purposes. The STAs (including the APs to which they are registered) form a service set, hereinafter referred to as a basic service set (BSS) (although other terms may be used). The same physical STA used as an access point may manage two or more BSSs (and therefore corresponding WLANs): each BSS is therefore uniquely identified by a specific basic service set identifier (BSSID) and managed by a separate virtual AP implemented in the physical AP. Each STA is identified within the BSS due to an identifier (AID) assigned to the STA by the AP at registration.

[0176] The 802.11 family of standards defines various Medium Access Control (MAC) mechanisms to drive access to the wireless medium.

[0177] As shown in the draft IEEE P802.11be / D2.2 in October 2022, current discussions in Task Group 802.11be introduce multi-link operation (MLO) when it comes to MAC layer operations. MLO allows multi-link devices to establish or set up multiple links and operate them simultaneously. These links are called "setup links" or "setup communication links."

[0178] A multi-link device (MLD) is a logical entity and has more than one subordinate STA (STA) and has a single medium access control (MAC) service access point (SAP) for a logical link control (LLC), which includes one MAC data service. An access point multi-link device (or AP MLD) then corresponds to an MLD in which the individual STAs subordinate to the MLD are APs and are therefore referred to as "subordinate APs." A non-access point multi-link device (or non-AP MLD) corresponds to an MLD in which the individual STAs subordinate to the MLD are non-AP STAs and are therefore referred to as "subordinate non-AP STAs." According to the text, "multi-link device," "ML device" (MLD), "multi-link logical entity," "ML logical entity" (MLE), "multi-link set," and "ML set" are synonyms for the same type of ML device. Reference is made below to Figure 1a and Figure 1b An example architecture of a multi-link device is described below.

[0179] Then, multiple subordinate non-AP STAs of the non-AP MLD may set up communication links with multiple subordinate APs of the AP MLD, thereby forming a multi-link channel.

[0180] The communication links (or enabling links) for MLD settings are theoretically independent, which means that the channel access process (to the communication medium) and the communication are performed independently on each link. Therefore, different communication links can have different data rates (e.g., due to different bandwidths, number of antennas, etc.) and can be used to communicate different types of information (each through a specific link).

[0181] Thus, setting up a communication link or enabling a link or just "a link" corresponds to a given channel (e.g., 20 MHz, 40 MHz, etc.) in a given frequency band (e.g., 2.4 GHz, 5 GHz, 6 GHz) between an AP attached to an AP MLD and a non-AP STA attached to a non-AP MLD.

[0182] The attached APs and non-AP STAs operate on their respective channels according to one or more of the IEEE 802.11 standards (a / b / g / n / ac / ad / af / ah / aj / ay / ax / be) and other wireless communication standards.

[0183] Due to multi-link aggregation, traffic associated with a single MLD can theoretically be transmitted across multiple parallel communication links, thereby increasing network capacity and maximizing the utilization of available resources.

[0184] From an architectural perspective, an MLD typically contains a number of radios to implement its affiliated STAs, but not necessarily a number equal to the number of its affiliated STAs. In particular, a non-AP MLD may operate with a greater number of affiliated STAs than the number of radios (which may even be reduced to a single radio).

[0185] Figure 1 A typical 802.11 network environment involving ML transmission between MLDs is illustrated, in which a single link tunneled direct link setup (TDLS) direct link according to the D2.2 standard may be established.

[0186] The wireless communication network 100 involves an AP MLD 110 and two non-AP MLDs 120 and 130. Of course, another number of non-AP MLDs that register with the AP MLD 110 and then exchange frames therewith can be envisioned.

[0187] One of the two non-AP MLDs can be a legacy 802.11 station. In this case, the "attached non-AP STA" mentioned below refers only to the legacy station itself.

[0188] AP MLD 110 has multiple subordinate APs. Figure 1 There are two attached APs 111 and 112 (also labeled as AP1 and AP2, respectively), each attached AP behaves as an 802.11 AP on its operating channel within a frequency band. Known 802.11 frequency bands include 2.4 GHz band, 5 GHz band and 6 GHz band. Of course, other frequency bands can be used to replace or supplement these three frequency bands.

[0189] The non-AP MLD 120, 130 has multiple subordinate non-AP STAs, each of which appears as an 802.11 non-AP STA in the BSS in which it is registered (managed by the subordinate AP 111 or 112). Figure 1 , two non-AP STAs 121 and 122 (also labeled as A1 and A2, respectively) are attached to the non-AP MLD 120, and two non-AP STAs 131 and 132 (also labeled as B1 and B2, respectively) are attached to the non-AP MLD 130.

[0190] For example, AP 111 is configured to operate on channel 38 corresponding to a 40 MHz operating channel in the 5 GHz band, and AP 112 is configured to operate on channel 151 corresponding to another 40 MHz operating channel in the 5 GHz band. In another example, the affiliated STAs may operate on different frequency bands.

[0191] Each subordinate AP provides a link toward the AP MLD 110 to the subordinate non-AP STAs of the non-AP MLD (120 or 130). Therefore, the links of each non-AP MLD can be identified only with the identifier of each subordinate AP. In this context, each subordinate AP 111 and 112 can be identified by an identifier called a "link ID". The link ID of each subordinate AP is unique and does not change during the life cycle of the AP MLD. The AP MLD can assign link IDs to its subordinate APs by incrementing the ID from 0 (for the first subordinate AP). Of course, other terms such as "AP ID" and the like can be used in variations.

[0192] In order to perform multi-link communication, each non-AP MLD 120, 130 must discover, authenticate, associate and set up multiple links with the AP MLD 110, each link being established between an AP affiliated with the AP MLD 110 and a non-AP STA affiliated with the non-AP MLD. Each such set up communication link (referred to as an enabling link) enables respective channel access and frame exchange between the non-AP MLD and the AP MLD based on the supported capabilities exchanged during association.

[0193] Figure 2 A possible scenario of the discovery and association process between a non-AP MLD and an AP MLD is illustrated using the frame exchanges in the timeline.

[0194] This example involves STA A1 121 attached to non-AP MLD 120 and AP1 111 attached to AP MLD 110 .

[0195] The discovery phase is referred to as the ML discovery process, and the multi-link setup phase (or association phase) is referred to as the ML setup process. The management frames exchanged during the ML discovery and ML setup processes contain a new information element specific to multi-link operation (MLO), which is referred to as the basic multi-link element, which conveys a description of the subsidiary STA entity other than the sending subsidiary STA entity (known as the "reporting STA") of the MLD used to send the frame. More precisely, the profile of the reporting STA (i.e., the STA used to send the frame) is provided in the information element (IE) of the frame other than the basic multi-link element. And, the basic multi-link element carries one or more per-STA profile sub-elements corresponding to each additional subsidiary STA (known as the "reported STA").

[0196] The ML discovery process allows a non-AP MLD to discover the wireless communication network 100, i.e., various links to the AP MLD provided by multiple subordinate APs. Therefore, the ML discovery process seeks various subordinate APs that advertise the AP MLD and corresponding network information, such as all or part of the capabilities and operating parameters. The discovery process mainly relies on the exchange of probe requests and probe responses between the AP and the non-AP. For ML discovery, discovery can be performed by using a probe request / response frame exchange for each link or an ML probe request / response frame exchange on one of the available links that carries all the information of various APs affiliated to the AP MLD. In addition, discovery can be based on active or passive scanning. In active scanning, the non-AP STA transmits a probe request 212 (with a wildcard SSID) and waits for a probe response 213 from the AP. In passive scanning, the non-AP STA listens on various channels for beacons 211 sent periodically by the AP on its operating channel, and then transmits a probe request 212 with the SSID corresponding to the AP of interest.

[0197] When sent by a non-AP MLD (e.g., non-AP MLD 120) via STA A1 121, the probe request frame 212 allows an affiliated non-AP station to request an affiliated AP (AP1 111) to include, in addition to its network information, a complete or partial set of capabilities and operating elements (i.e., network information) of other APs affiliated to the same AP MLD.

[0198] When sent by an AP MLD (e.g., AP MLD 110) via AP1 111, a beacon frame 211 or a probe response frame 213 includes a simplified neighbor report element (in Fig. 9 The simplified neighbor report element contains channel and other information related to the neighbor AP, and the basic multilink element carries one or more per-STA profile sub-elements describing all information of the APs attached to the AP MLD. Fig.5a1 and Fig.5a2 The multilink element is described in its basic variant.

[0199] Among the various capabilities exchanged by the AP and the non-AP during the discovery process, channel usage information may be provided by the AP to the non-AP STA in the probe response frame 213 to advise the STA on how to coexist with the infrastructure network, and more particularly, to recommend a channel for a BSS that is not an infrastructure BSS or an off-channel TDLS direct link. Thus, the non-AP STA may use the channel usage information as part of a channel selection process for a BSS that is not an infrastructure BSS or an off-channel TDLS direct link.

[0200] The channel usage information is a set of channels provided by the AP to the non-AP STA for operation of a non-infrastructure network or an off-channel TDLS direct link. A non-AP STA that supports channel usage and is interested in using a non-infrastructure network or an off-channel TDLS direct link can include both a supported operation class (as defined by the supported operation class element in IEEE 802.11-REVme / D1.3 (June 2022), section 9.4.2.53) and a channel usage element (as defined by the channel usage element in IEEE802.11-REVme / D2.0 (October 2022), section 9.4.2.85) in the probe request frame 212. The AP that supports channel usage should then send a probe response 213 frame including one or more channel usage elements. Reference Figure 6 Further describing the channel usage element. We can also note that a non-AP STA supporting channel usage can send a channel usage request frame at any time after associating to an AP supporting channel usage to request channel usage information for supported operation classes, i.e., requesting a channel for non-infrastructure network operation or off-channel TDLS direct link operation.

[0201] Once the non-AP MLD has discovered the wireless communication network 100 through the ML discovery process and after the MLD authentication process, the ML setup process (based on the association request 214 frame and the association response 215 frame) allows the non-AP MLD to select a set of candidate setup links between its own subordinate non-AP STA and some discovered subordinate APs, and request the AP MLD 110 to setup these links, which can be accepted or rejected by the AP MLD. If the AP MLD accepts, the AP MLD provides the non-AP MLD with an association identifier (AID), which is used by the subordinate non-AP of the non-AP MLD to wirelessly communicate with its corresponding subordinate AP on multiple links (communication channels).

[0202] During the ML setup process, the non-AP MLD declares some or all of its capabilities. For example, the non-AP MLD can declare its tunneled direct link setup (TDLS) capability, which enables devices (called TDLS peer STAs) to communicate directly with each other when connected to a regular AP. For this purpose, appropriate fields are provided in management frames. In fact, in all management frames, a non-AP MLD that can act as a TDLS initiator STA or a TDLS responder STA (dot11TunneledDirectLinkSetupImplemented is true) sets the TDLS support bit (bit 37) in the extended capability element to 1.

[0203] Similar to TDLS support, non-AP MLD or AP MLD can also declare whether channel usage is activated (dot11ChannelUsageActivated is true) by setting the channel usage bit (bit 24) in the extended capability element to 1, allowing devices to exchange their channel usage information.

[0204] For the purpose of illustration, in the wireless communication network 100, during the ML setup process, two candidate setup links have been requested by the non-AP MLD 120 and accepted by the AP MLD 110: a first link 151 between the attached AP 111 (AP1) and the attached non-AP STA 121 (A1), and a second link 152 between the attached AP 112 (AP2) and the attached non-AP STA 122 (A2). Similarly, two candidate setup links have been requested by the multi-radio non-AP MLD 130 and accepted by the AP MLD 110: a first link 161 between the attached AP 111 (AP1) and the attached non-AP STA 131 (B1), and a second link 162 between the attached AP 112 (AP2) and the attached non-AP STA 132 (B2).

[0205] refer to Figure 6 , the data payload of the channel usage element is shown under reference numeral 600. The channel usage element consists of four fields: an element ID field 610, a length field 620, a usage mode field 630, and a channel entry field 640.

[0206] In the IEEE P802.11-REVme / D2.0 version (October 2022), two different values ​​are defined for the usage mode field 630, namely, a value of 0 for non-infrastructure IEEE 802.11 networks and a value of 1 for off-channel TDLS direct links. Recent adaptations of the standard seek to provide a new value of 2 for non-infrastructure IEEE 802.11 networks, where none of the APs belonging to the same ESS operates an infrastructure BSS. Values ​​3 to 255 are reserved.

[0207] The channel entry field 640 includes zero or more than zero operation class 641 and channel 642 fields. The operation class field 641 indicates the operation class value. The operation class (defining the radio frequency, channel center frequency, maximum channel width, and behavior constraints) is interpreted in the context of the region specified in the beacon frame. The channel field 642 indicates the channel number interpreted in the context of the indicated operation class. The operation class and channel number are defined in Appendix E of the IEEE P802.11-REVme / D1.3 version. As described in 9.4.2.70.3 (Location Indication Channel Sub-Element), the operation class and channel fields can be grouped together to identify non-contiguous channels.

[0208] Fig. 9 The format of the Reduced Neighbor Report (RNR) information element 910 present in every beacon is described.

[0209] The element ID field 911 is equal to the value 101 to indicate that the type of the information element is RNR.

[0210] The length field 912 indicates the length in octets of the included information element.

[0211] Neighbor AP Information Field 913 contains one or more (in Fig. 9 In the example of n (n) neighbor AP information fields 920, each neighbor AP information field 920 provides an element about a reported AP that is different from the reporting AP (the AP that sent the information element). Figure 2 In the example of , beacon 211 will contain at least one neighbor AP information field 920 corresponding to AP2 (e.g., the reported AP). In addition, there may be several other fields 920 to give information from APs that are not affiliated with the reporting AP MLD but are known by the reporting AP (e.g., APs co-located in the same building but operating different MLDs).

[0212] Each neighbor AP information field 920 includes a TBTT information header subfield 921 , an operation class subfield 922 , a channel number subfield 923 , and a TBTT information set subfield 924 .

[0213] The TBTT information header subfield 921 contains several fields indicating how many TBTT information fields 930 (TBTT information count) and their types (TBTT information field type) exist in the TBTT information set subfield 924.

[0214] Each TBTT information field 930 includes a neighbor AP TBTT offset subfield 931 and an MLD parameter subfield 940 .

[0215] The Neighbor AP TBTT Offset subfield 931 indicates the offset in TUs (rounded down to the nearest TU) from the immediately preceding TBTT of the AP transmitting the element to the next TBTT of the AP's BSS. A value of 254 indicates an offset of 254 TUs or higher. A value of 255 indicates an unknown offset value.

[0216] The MLD parameter field 940 contains information related to the link associated with the reported AP. More specifically, the MLD parameter field 940 includes an MLD ID subfield 941 , a link ID subfield 942 , and a BSS parameter change count subfield 943 .

[0217] The MLD ID subfield 941 indicates the identifier of the AP MLD to which the reported AP belongs. If the reported AP belongs to the same MLD as the reporting AP, the MLD ID subfield 941 is set to 0. If the reported AP is part of another AP MLD, the MLD ID subfield is set to a value higher than 0. For example, if the reported AP belongs to the same MLD as the non-transmitting BSSID (which is in the same set of multiple BSSIDs as the reporting AP), the MLD ID subfield 941 is set to the same value as in the BSSID Index field in the Multiple BSSID Index element in the Non-Transmitting BSSID Profile corresponding to the non-transmitting BSSID.

[0218] Link ID subfield 942 is a unique identifier (within the MLD) of the link.

[0219] The BSS Parameter Change Count subfield 943 contains a counter that is incremented (modulo 255) each time a critical parameter of the BSS is updated in a beacon frame of the reported AP.

[0220] The format of the basic variant multilink element 500 is Fig.5a1 and Fig.5a2 The basic variant multilink element 500 includes an element ID field 501, a length field 502 (making it possible to know the presence or absence of optional fields and the number of profiles per STA in field 530), an element ID extension field 503, a multilink control field 510, a common information field 520, and an optional link information field 529.

[0221] The multilink control field 510 includes a type subfield 511, a reserved subfield 512, and a presence bitmap subfield 513. The type subfield 511 is set to a value of 0 to signal that the multilink element 300 is a basic variant ML element. The presence bitmap subfield 513 tells which parameters are present or absent in the common information field 520. The common information field 520 includes a link ID information presence subfield, a BSS parameter change count presence subfield, a medium synchronization delay information presence subfield, an EML capability presence subfield, an MLD capability and operation presence subfield, an MLD ID presence subfield, and a reserved subfield.

[0222] The common information field 520 always includes a common information length field 521, an MLD MAC address subfield 522, and depending on the value specified in the presence bitmap subfield 320, the common information field 520 optionally includes a link ID information subfield 523, a BSS parameter change count subfield 524, a medium synchronization delay information subfield 525, an EML capability subfield 526, an MLD capability and operation subfield 527, and an MLD ID subfield 528.

[0223] More specifically, the link ID information subfield 523 includes a link ID subfield 523a and a reserved field 523b. The link ID subfield 523a conveys reporting of a link ID on which an affiliated (AP or non-AP) STA operates.

[0224] If the Link Information field 529 is present, one or more per-STA profile sub-elements 530 are included as a list of sub-elements 530, each sub-element 530 describing a reported affiliated (AP or non-AP) STA of the same MLD.

[0225] like Fig.5a2 As detailed in , each STA profile sub-element 530 includes a sub-element ID field 531, a length field 532, a STA control field 533, a STA information field 534, and a STA profile field 535.

[0226] The STA Control field 533 includes a Link ID subfield 540 that specifies a value that uniquely identifies the link on which the reported STA is operating.

[0227] The STA control field 533 additionally includes a complete profile subfield 541, a STAMAC address presence subfield 542, a beacon interval presence subfield 543, a TSF offset presence subfield 544, a DTIM information presence subfield 545, an NSTR link pair presence subfield 546, an NSTR bitmap size subfield 547, a BSS parameter change count presence subfield 548 and a reserved subfield 549.

[0228] If the STA MAC address field exists in the STA information field 534, the STA MAC address exists subfield 542 is set to 1. Otherwise, this subfield is set to 0.

[0229] If the Beacon Interval subfield exists in the STA Information field 534, the Beacon Interval Existence subfield 543 is set to 1. Otherwise, this subfield is set to 0.

[0230] If the TSF offset subfield is present in the STA information field 534, the TSF offset present subfield 544 is set to 1. Otherwise, this subfield is set to 0.

[0231] If the DTIM information subfield exists in the STA information field 534, the DTIM information present subfield 545 is set to 1. Otherwise, this subfield is set to 0.

[0232] If the NSTR indication bitmap subfield is present in the STA information field 534, the NSTR link pair present subfield 546 is set to 1. Otherwise, this subfield is set to 0.

[0233] If the BSS parameter change count subfield exists in the STA information field 534, the BSS parameter change count existence subfield 548 is set to 1. Otherwise, this subfield is set to 0.

[0234] The STA information field 534 includes a STA information length subfield 550, and depending on the value specified in the STA control subfield (542-548), the STA information field 534 optionally includes a STAMAC address subfield 551, a beacon interval subfield 552, a TSF offset subfield 553, a DTIM information subfield 554, an NSTR indication bitmap subfield 555 (whose size depends on the NSTR bitmap size subfield) and a BSS parameter change count subfield 556.

[0235] The STA profile field 535 carries a variable number of fields and elements in the order defined in different frame bodies corresponding to the frames carrying the multilink elements. For example, the STA profile included in the multilink element carried in the association request frame refers to Table 9-62 Association Request Frame Body.

[0236] The per-STA profile shall not include the following elements: Neighbor Report Element, Simplified Neighbor Report Element, Multi-BSSID Element, TIM Element, Multi-BSSID Index Element, Multi-BSSID Configuration Element, or another Basic Multilink element in the per-STA profile sub-element.

[0237] Figure 1aAn exemplary 802.11be multi-link reference model for MLD (AP MLD or non-AP MLD) is illustrated.

[0238] The MLD includes a PHY layer 200, a MAC layer 220, a logical link control (LLC) sublayer, and an upper layer. The upper layer may include an application that generates traffic data or uses received traffic data.

[0239] The transmission and reception of traffic data is handled by the MAC 220 and PHY 200 layers. Such transmission and reception of traffic data may be performed over multiple links 20-x, 20-y, 20-z (see reference Figure 1 151, 152, 161, 162) and on the single link TDLS direct link 171 (see Figure 1 ) is performed on a 32-bit network. Three links are shown in the figure, and therefore three auxiliary stations are shown. Of course, other configurations including two auxiliary stations or more than three auxiliary stations can be envisaged.

[0240] Traffic data is provided by upper layers as a sequence of data frames or "traffic flows". Each traffic flow, and therefore each data frame, is associated with an access category (AC) defined in the EDCA mechanism ( Figure 1b ). This mapping between flows or data frames and ACs is performed by classifier 213.

[0241] Recall that 802.11 stations (AP and non-AP stations) maintain four access categories (ACs), each with one or more corresponding transmission buffers or queues. The four ACs are generally defined as follows:

[0242] -AC1 and AC0 are reserved for best effort and background traffic. They have the second-lowest priority and the lowest priority respectively; and

[0243] - AC3 and AC2 are usually reserved for real-time applications (eg, voice or video transmission). They have the highest priority and the second-to-last priority, respectively.

[0244] Data frames incoming from upper layers of the protocol stack, known as MAC Service Data Units (MSDUs), are mapped by classifier 213 onto one of the four ACs and are thus entered in the queue of the mapped AC for transmission.

[0245] Figure 1b An implementation model with four transmit queues (one for each access category) is illustrated.

[0246] The 802.11be multi-link reference model reflects the fact that an MLD may use several links for transmission and reception (particularly at the MAC layer 220 and PHY layer 200 levels).

[0247] The MAC layer 220 includes a unified upper MAC (UMAC) layer 230, and multiple lower MAC (LMAC) layers 220-x, 220-y, 220-z coupled with corresponding PHY layers 200-x, 200-y, 200-z, each coupling corresponding to the links 20-x, 20-y, 20-z.

[0248] The UMAC 230 performs functions that are common across all links, and each LMAC 220-x, 220-y, 220-z performs functions that are local to each link 20-x, 20-y, 20-z. The UMAC layer then provides a UMAC interface with the link-specific blocks 220-x, 220-y, 220-z, and also provides a UMAC Service Access Point (SAP) to the LLC and upper layers.

[0249] The UMAC 230 is responsible for link-agnostic MAC processes such as authentication, association, security association, sequence number assignment, MAC Protocol Data Unit (MPDU) encryption / decryption, aggregation / deaggregation, confirmation score boarding process, and the like.

[0250] Each data unit (MSDU) with a traffic type (user priority (UP), and thus traffic identifier (TID)) priority, arriving at the MAC layer 220 from an upper layer (e.g., link layer) is mapped onto one of the ACs according to a mapping rule at the UMAC layer 230. Then, still at the UMAC layer 230, the data unit (MSDU) is provided with the next available sequence number and is stored in a queue corresponding to its TID (or UP) within the mapped AC.

[0251] Each LMAC 220-x, 220-y, 220-z is responsible for link-specific functions such as channel access. In particular, each MLD MAC includes its own contention-based channel access process, such as EDCA 221-x, 221-y, 221-z. Some functions require joint processing of both the UMAC 230 and the LMAC 220-x, 220-y, 220-z.

[0252] like Figure 1a and Figure 1bAs shown, each EDCA 221-x, 221-y, 221-z of each link competes for each queue for each link. In this regard, each AC has its own set of queue competition parameters for each link, and is associated with a priority value, thus defining higher or lower priority traffic for the MSDU. Therefore, for a given link, there are multiple traffic queues for serving data traffic at different priorities. The contention window (CW) and backoff value are known as EDCA variables and are specific to each link 20-x, 20-y, 20-z.

[0253] This means that each AC acts as an independent DCF competition entity on a given link (including its corresponding queue backoff engine 211). Therefore, each queue backoff engine 211 is associated with a corresponding traffic queue 210 for using queue competition parameters and extracting backoff values ​​(from CW) to initialize a corresponding queue backoff counter specific to each AC and each link. The backoff counter is used to compete for access to the links 20-x, 20-y, 20-z to transmit data stored in the queue of the AC. In practice, when the medium is idle, the backoff counter is decremented from its initialization value, and when the backoff counter reaches 0, the corresponding affiliated STA201-x, 201-z is allowed to transmit (access is granted).

[0254] When access to the wireless medium is granted for an AC on a link, the MSDU stored for that AC is transmitted to the physical (PHY) layer 200-x, 200-y, 200-z for transmission on the link.

[0255] The subordinate STA entities 111-121-131 (112-122-132 above) use a conventional EDCA (Enhanced Distributed Channel Access) contention scheme to compete with each other on their common channel to access the wireless medium, thereby being granted a transmission opportunity (TXOP) and then sending (single user (SU)) data frames. The subordinate STAs 121-131 (122-132 above) can also use a multi-user (MU) scheme, in which the subordinate AP 111 (112 above) of the AP MLD 110 is allowed to schedule MU transmissions in the wireless network, that is, multiple simultaneous transmissions to or from stations of its BSS. For example, one implementation of such a MU scheme has been adopted in the IEEE Std 802.11ax-2021 standard as a multi-user uplink and downlink OFDMA (MU UL and DL OFDMA) process.

[0256] Reference now Figure 2a Describes the single link TDLS direct link mechanism in the MLD context, Figure 2aThe possible scenarios for handling P2P traffic for an initiator peer non-AP STA or an initiator TDLS peer STA (affiliated non-AP STA) are illustrated using the frame exchanges in the timeline.

[0257] This example involves STA A1 121 as an initiator of P2P communication and STA B1 131 as a partner or responder of P2P communication 171. They both occupy part of the same BSS on a given link 1 (151 / 161) and are associated with AP 111. As described above, STA A1 and STA B1 may be non-AP stations attached to respective non-AP MLDs, while AP 111 may be an AP attached to AP MLD 110.

[0258] In this sequence, once STA A1 and STA B1 are associated with the AP (association not shown), they can exchange data through the AP on their operating links.

[0259] To reduce the amount of traffic passed in the network and prevent congestion at the AP, the IEEE 802.11z amendment has defined a mechanism known as Tunneled Direct Link Setup (TDLS), which allows 802.11 non-AP stations to set up direct links between them while also remaining associated with the AP. The D2.2 standard upgrades the conventional TDLS mechanism to work with the multi-link feature.

[0260] Tunneled Direct Link Setup (TDLS) is characterized by the use of signaling frames encapsulated in 802.11 data frames so that the signaling frames are transmitted transparently through the AP. Therefore, the AP does not need to be direct link aware, nor does it need to support the same set of capabilities used on the direct link to use TDLS.

[0261] In the sequence shown, a TDLS session or "TDLS direct link" is established between STA A1 and STA B1 (either of which can be the initiator of the TDLS direct link establishment). The establishment may include a TDLS discovery procedure (optional) and a TDLS setup procedure.

[0262] The TDLS discovery process and setup process between STA A1 and STA B1 involves what are known as TDLS action frames (see Figure 3 The TDLS process is characterized by encapsulating signaling frames (TDLS action frames) in 802.11 data frames, which allows the signaling frames to be transmitted transparently (hence "tunneled") through the AP.

[0263] When trying to discover TDLS stations in the same BSS, a series of frame exchanges are used. STA A1, being the initiator in the proposed scenario, sends a TDLS discovery request frame 221 tunneled through AP 111 (relay illustrated by black dots) to a single destination station (here STA B1).

[0264] The request frame (described below as a TDLS Setup Request / Response / Confirmation frame and a TDLS Discovery Response frame) conveys a so-called "Link Identifier" element in the IE of the element field 303 (see Figure 4a ) and the "TDLS Multilink" element (see Figure 4b ). Other IEs forming element field 303 are defined in Table 9-507 as defined in IEEE 802.11-REVme / D2.0 (October 2022).

[0265] The link identifier element is Figure 4a 400. The link identifier element includes a BBSID field 401, a TDLS initiator STA address field 402, and a TDLS responder STA address field 403. When a frame carrying the element is transmitted by a STA that is not affiliated with a non-AP MLD, the BSSID field 401 is set to the BSSID of the BSS of which the TDLS initiator STA A1 is a member. Otherwise, in the context of MLD operation, the BSSID field is set to the BSSID of the AP operating on the link on which the non-AP MLD 120 intends to establish a single link TDLS direct link. The TDLS initiator STA address field 402 is set to the MAC address of the TDLS initiator, which is the MLD MAC address of MLD A 120 in the context of MLD operation. The TDLS responder STA address field 403 is set to the MAC address of the TDLS responder, which is the MLD MAC address of MLD B 130 in the context of MLD operation.

[0266] Destination station STA B1 responds to TDLS discovery request frame 221 with a TDLS discovery response frame 222 sent directly (without relay of AP 111) to STA A1. The response frame conveys the "Link Identifier" element and the "TDLS Multilink" element in the IE of the element field 303.

[0267] From this point on, STA A1 and STA B1 are aware of each other, which means they know that the other is operating on the same link set up with AP 111. They can then establish a TDLS direct link.

[0268] When attempting to establish a TDLS direct link with a discovered TDLS station over a single link, a series of TDLS action frame exchanges are used to set up the single link TDLS direct link.

[0269] The TDLS initiator STA A1 first sends a TDLS setup request frame 223 tunneled through AP 111 (a relay illustrated by a black dot) to the target TDLS responder STA B1. The request frame conveys the "Link Identifier" element and the "TDLS Multilink" element in the IE of the element field 303. Other IEs forming the element field 303 are defined in Table 9-497 as defined in IEEE 802.11-REVme / D2.0 (October 2022), which include information about the capabilities of the TDLS initiator STA A1 and its AID.

[0270] The TDLS responder STA B1 responds with a TDLS setup response frame 224, which is also tunneled through the AP 111. The response frame conveys the "Link Identifier" element and the "TDLS Multilink" element in the IE of the element field 303. Other IEs forming the element field 303 are defined in Table 9-498 as defined in IEEE 802.11-REVme / D2.0 (October 2022), which include information about the capabilities of the TDLS responder STA B1, its AID, and a status code for accepting or rejecting the setup request.

[0271] If the setup request is accepted, the TDLS initiator STA A1 then sends a confirmation TDLS setup confirmation frame 225, which is still tunneled through the AP 111. The confirmation frame conveys the "link identifier" element and the "TDLS multilink" element in the IE of the element field 303. The other IEs that form the element field 303 are defined in Table 9-499 as defined in IEEE 802.11-REVme / D2.0 (October 2022).

[0272] This concludes the TDLS setup handshake. At this point, the two non-AP MLDs know each other's identities through their MLD MAC addresses on the one hand and the AP MLD-assigned AID on the other hand.

[0273] During the TDLS setup handshake, the TDLS STA (initiator and responder) can establish a Robust Security Network Association (RSNA) for the TDLS direct link. This security protection for the TDLS direct link follows the security between the STA and its AP, so if any security method is enabled for the connection between the STA and the AP, the STA requires the successful completion of the security protocol before using the TDLS direct link. If no security method is enabled for the connection between the STA and the AP, the STA does not use any security protocol for the TDLS direct link.

[0274] To secure the TDLS direct link, the TDLS STA uses the TDLS PeerKey (TPK) security protocol (as defined in IEEE 802.11-REVme / D2.0 (October 2022), section 12.7.8). The TPK key is derived by each TDLS STA during the TDLS setup handshake and relies on information elements included in the TDLS frame, namely (as described in Table 399 below) the "Link Identifier" element, the "Robust Security Network" element (RSNE), the "Timeout Interval" (TPK Key Lifetime) or TIE element, and the "Fast BSS Transition" or FTE element. Some information related to the TDLS session itself is used for TPK derivation. Such information (e.g., the MAC address of the TDLS initiator, the MAC address of the TDLS responder, and the BSSID) is retrieved directly from the Link Identifier element shared between the two TDLS STAs. The D2.2 standard slightly revised the process to support non-AP MLDs to establish a single link TDLS direct link. Therefore, to support this new procedure, a "TDLS Multi-Link" element is added in the TDLS Setup frame, and the AP MLD MAC address conveyed by the "TDLS Multi-Link" element is added as a new parameter to derive the TPK to be used for multiple-link TDLS sessions.

[0275] The stations can then start communicating directly on the link 171 (direct link): P2P traffic 226 can then be exchanged directly between STA A1 and STA B1 (without the black dot shown at the AP in the figure for arrow 226) using the established TDLS session. The TDLS peers STA A1 and STA B1 are then configured to accept data frames received directly from the other peer. The frame exchange is performed on the same link, that is, on the same frequency channel, so that the P2P traffic becomes concurrent with other traffic for AP1 111.

[0276] Figure 1Reference numeral 171 in exemplifies a single link TDLS direct link, which, if established, allows MLD A 120 (through subordinate STA A1 121 ) and MLD B 130 (through subordinate STA B1 131 ) to directly exchange data without relaying of the AP MLD 110 .

[0277] In order to avoid traffic competition with the AP, a tunneled direct link setup (TDLS) station that supports TDLS channel switching can decide to perform TDLS channel switching to a supported channel. During the TDLS setup process, the TDLS stations inform each other of the channels they support, that is, the TDLS station includes supported channel elements and supported operation class elements in all TDLS setup requests and TDLS setup response frames with a TDLS channel switching subfield equal to 1. More advantageously, the TDLS station can move from a basic channel (i.e., the channel corresponding to the link set with the AP (AP1 111) in the above example) to an off-channel, that is, a channel that does not overlap with the (one or more) channels used by the access point (AP) associated with the TDLS station. Recall that the off-channel available for TDLS is provided by the AP through a channel usage element 600 transmitted in a probe response 213 or a channel usage response frame.

[0278] Return to Figure 2a In the example of , the TDLS STA initiator 121 sends a TDLS channel switch request frame 231 on the TDLS direct link. The frame includes a target channel, i.e., the destination channel of the intended channel switch. The target channel is specified by the STA initiating the channel switch from the set of operation classes supported by the two TDLS peer STAs. Upon receiving the TDLS channel switch request frame 231, the target partner STAB1 131 responds with a TDLS channel switch response frame 232 to accept or reject the channel switch. If the status code indicated in the response frame is set to REQUEST_DECLINED, the two stations continue to operate on the current channel. Otherwise, if the status code is set to success in the response frame, the two stations should move to the target channel before the switching time also indicated in the TDLS channel switch frame, but the first transmission should not start before the end of the switching time. Finally, after the switching time has passed, the initiator STAA1 can transmit a P2P data frame on the target channel.

[0279] The use of the off-channel remains within the operations performed by the TDLS STA in the initially established TDLS direct link, ie, associated with the link ID of the link still set up with AP1 111.

[0280] When operating via an off-channel, a TDLS STA is in power saving mode with the AP and is no longer able to communicate with the AP on the basic channel of the link. Therefore, the TDLS STA must regularly return to the basic channel to receive beacons, check the TIM (Traffic Indication Map) for any buffered packets, and communicate with other devices in the network.

[0281] Details on the TDLS procedure are provided in IEEE 802.11z, and have been upgraded to establish the TDLS procedure over one of possible multiple links as provided in the D2.2 standard.

[0282] Figure 3 The format of an 802.11 action frame 300 is illustrated. The figure shows only the payload of such an action frame, omitting the MAC header for simplicity.

[0283] The action frame 300 has a format of a frame, and thus has a category field 301 , an action field 302 immediately following the category field 301 , and an element field 303 .

[0284] Various values ​​of the category field 301 are defined in the 802.11 standard and correspond to various action frames. A category field set to 12 defines a TDLS action frame, while a category field set to 4 defines a public action frame.

[0285] TDLS action frames convey TDLS signaling notifications.

[0286] As shown in Table 9-496 of the 802.11 standard (as an example, IEEE 802.11-REVme / D2.0 (October 2022)), the 1-byte action field 302 for the TDLS action frame can take various values ​​from 0 to 10 (11 to 255 are reserved) to signal different types of TDLS action frames, each of which has its own function in the TDLS mechanism. For example, the TDLS setup request frame 213 is identified by setting the action field 302 to 0; the TDLS setup response frame 214 is identified by setting the action field 302 to 1; the TDLS setup confirmation frame 215 is identified by setting the action field 302 to 2; the TDLS channel switch request frame 231 is identified by setting the action field 302 to 5; and the TDLS channel switch response frame 232 is identified by setting the action field 302 to 6.

[0287] Table 399 below is provided for illustrative purposes only to show an exemplary IE of the element field 303 to be provided in a TDLS Set Action frame (i.e., the Action field 302 is set to 0, 1, or 2). Each type of TDLS Action frame has its own set of elements 303 to be provided, identifying the frame (category, TDLS action, and dialog tokens as defined in the standard).

[0288] The action field of the TDLS Setup Request action field contains the information shown below, while the corresponding TDLS Setup Response action field contains information only if the status code is Success.

[0289]

[0290]

[0291]

[0292] Table 399

[0293] The Action field of the TDLS Setup Confirm Action field may contain a subset of this list, where the Capability IE is replaced by the Operation IE (e.g., the HT / VHT / HE / EHT Capability IE is replaced by the HT / VHT / HE / EHT Operation IE).

[0294] Of the elements of most interest for the purposes of the present invention, the Supported Channels and Supported Classes of Operation elements are used by peer STAs to inform each other of possible channels to operate on off-channel.

[0295] IEEE P802.11be / D2.2 version has envisioned enabling the setup of TDLS direct links over a single communication link of MLD.

[0296] like Figure 4b As described above, all TDLS discovery and setup request and response frames include TDLS multilink IE. TDLS multilink IE 450 is based on the structure of multilink elements introduced to support several links (e.g., the basic version is used for the association of MLD), and therefore consists of the following items:

[0297] Element ID 451 is equal to 255,

[0298] The length field 452 defines the length of the information element,

[0299] Element ID extension field 453 is set to identify the multilink IE 107,

[0300] The Multilink Control field 460 allows the use of the Type field 461 to define the type of the Multilink IE as TDLS (value: 3),

[0301] The common information field 470 includes a common information length field 471 and an AP MLD MAC address field 472 which is set to the MAC address of the AP to which the TDLS initiator non-AP STA is attached,

[0302] • The Link Information field 480 is reserved (which means not used).

[0303] Therefore, the TDLS multi-link IE 450 allows each peer non-AP STA to share the APMLD MAC address of the AP MLD in a multi-link environment.

[0304] If the TDLS (discovery / setup) frame carries a TDLS multilink element 450 and the MLD MAC address carried in the APMLD MAC address field 472 of the TDLS multilink element 450 matches the MLD MAC address of the AP MLD for which the non-AP MLD has performed multilink setup, the TDLS STA attached to the non-AP MLD will only consider the TDLS (discovery / setup) frame.

[0305] Outside the scope of TDLS, IEEE P802.11be / D2.2 version also envisions enabling descriptions of links for MLDs. Between an AP MLD and a non-AP MLD associated with the AP MLD, the MLD may transmit to another STA a separately addressed management frame (MMPDU) intended for one or more STAs attached to the associated MLD. In other words, the MMPDU will be distributed via a given link(s) that is different from the link(s) associated with the management information (e.g., it is also possible that the information is intended for more than one STA / link, or is intended to be retransmitted on different STAs). According to Figure 4c , the multilink link information element 490 identifies the intended link(s) of the MMPDU that carries the element. The link ID bitmap field indicates the link(s) on which the intended STA(s) are operating (for the use of link IDs, see 35.3.2.1 (Overview)). This illustration of link identification will further be considered as another means of being useful to the embodiments.

[0306] Therefore, the D2.2 standard allows direct link communications between non-AP MLDs utilizing one or more than one single-link TDLS direct links. This means that separate and independent TDLS sessions can be established over multiple links via multiple affiliated STAs of the same non-AP MLD.

[0307] We can note from the above description that, despite being of great interest in improving the coexistence between infrastructure and P2P communications, the use of off-channels follows the traditional behavior of not utilizing the multi-radio / multi-link capabilities of the device. Thus, a non-AP MLD cannot maintain communication with its AP MLD (or AP) over one link while the other link can reside on an off-channel for P2P communications. In contrast, the use of off-channels is still performed by a TDLS channel switch from the base channel to one of the off-channels, thus requiring repeated TDLS channel switches to switch back and forth between the base channel and the off-channel.

[0308] Note that this constraint between the base channel and the off-channel arises from using the same enabling link to support both channels. This is because, as it stands, non-AP MLDs only rely on links set up with AP MLDs.

[0309] The inventors intend to overcome some of the aforementioned problems by providing an off-link solution (i.e., an extension of off-channel usage that allows persistent use of the network resources while maintaining a link dedicated to communications with the AP). This is achieved by dedicating a link (and therefore a link ID) to direct communications on the off-channel. Thus, an "off-link" is defined that is separate from the link operating with the AP.

[0310] As an example, an AP MLD (or device) may instantiate a virtual AP that does not communicate in the BSS of the AP MLD. The virtual AP defines an off-link corresponding to at least one off-channel that does not overlap with a channel (or channels) used by (one or more) other APs attached to the AP MLD. Therefore, the virtual AP is assigned a link identifier ID, thereby identifying the off-link to be used by the non-AP MLD to set up a TDLS direct link.

[0311] Figure 7a The present invention can be implemented as follows Figure 1 An 802.11 network environment involving a multi-radio device MLD. Figure 7aThe example presents two non-AP MLDs (non-AP MLD A 120 and non-AP MLD B 130) with three affiliated STAs (121 to 123 and 131 to 133, respectively) and an AP MLD 110 with three affiliated APs 111, 112, and 113. AP 113 is an instantiation of a virtual AP whose purpose is to obtain a link ID corresponding to a set of (one or more than one) off-channels (at least one off-channel) to support off-links 173 for operations outside of AP MLD management. As a result, non-AP MLDs 120 and 130 are able to use off-links 173 of one of their affiliated stations while maintaining a previous connection with the AP MLD through links 1 and 2 corresponding to the connections with affiliated AP1 and AP2, respectively.

[0312] Of course, for purposes of illustration, the number of links shown in this figure is not limiting.

[0313] Figure 7b The present invention can be implemented by Figure 1 Another 802.11 network environment involving a multi-radio device MLD. Figure 7b The example presents two non-AP MLDs (non-AP MLD A 120 and non-AP MLD B 130) with two affiliated STAs (from 121 to 122 and from 131 to 132, respectively) and an AP MLD 110 with four affiliated APs 111, 112, 113 and 114. APs 113 and 114 are instantiations of virtual APs, each of which has the purpose of obtaining a link ID. The links associated with AP 113 correspond to a first set of (one or more than one) off channels, and it enables off link 173. The links associated with AP 114 correspond to a second set of (one or more than one) off channels that enable another off link (not shown in the figure). Virtual APs 113 and 114 can optionally be affiliated with a virtual AP MLD 110b with a specific MLD ID. As a result, non-APMLDs 120 and 130 are able to use an off-link (eg, 173) with one of their affiliated stations while maintaining a previous connection with AP MLD via link 1 corresponding to the connection with affiliated AP1.

[0314] Figure 7c Example operations for wireless communications performed by an AP MLD for instantiation of a virtual AP in accordance with certain aspects of the present disclosure are illustrated.

[0315] Operations may begin at step 710, where an AP MLD (e.g., 110) receives a trigger to instantiate a virtual AP. For example, the trigger may be a probe request frame 212 received from a non-AP MLD that has not yet been associated, the probe request frame 212 including an off-link capability and / or a channel usage element as a new input (e.g., bit 90) in an extended capability element. After association, the non-AP MLD may request assistance to set up a non-infrastructure network on an off-channel, i.e., an off-link, by sending a channel usage request to the AP MLD (wherein the usage mode field of the channel usage element is set to 2). In an alternative, the trigger may be a QoS feature such as defined by Draft 2.0, which has a direction subfield whose value corresponds to direct link communication. In an alternative, the trigger may be an internal trigger, for example, if the AP MLD supports virtual AP or off-link capabilities, the AP MLD may set up an off-link by instantiation of a virtual AP. In another alternative, the AP MLD may instantiate a virtual AP for any reason without a specific trigger.

[0316] In other words, the trigger to instantiate a secondary virtual AP belongs to the group consisting of:

[0317] - receiving a probe request frame (212, 812) from the non-AP MLD, the probe request frame (212, 812) including the off-link capability and / or channel usage element (600) as a new input in the extended capabilities, if the non-AP MLD is not already associated with the AP MLD;

[0318] - In case the non-AP MLD has been associated with the AP MLD, receiving a channel usage request frame (815) from the non-AP MLD, the channel usage request frame including a channel usage element requesting setup of an off-link;

[0319] - receiving Quality of Service (QoS) characteristics; and

[0320] -Detect AP MLD internal trigger.

[0321] At step 720, the AP MLD (e.g., 110) instantiates a virtual AP 113 (at least one, even if the description focuses on one VAP), that is, assigns an AP ID that can be further used as a link ID. The purpose of the virtual AP instantiation is to obtain at least one link ID. In other words, the AP MLD instantiation defines an attached virtual AP of an off-link corresponding to at least one off-channel that does not overlap with the channel (one or more than one) used by the AP MLD, the attached virtual AP is assigned a link identifier ID, thereby identifying the off-link, and the virtual AP does not communicate in its basic service set (BSS).

[0322] Then, in step 730, the AP MLD defines the characteristics of the virtual AP except the link ID, such as the operation class, channel number, channel width for defining the operation band, BSSID, information related to the BSSID indicating that the virtual AP is unreachable, non-inherited elements, etc.

[0323] In certain embodiments, a specific value from the AP reachability field of the BSSID information element, such as defined in IEEE P802.11-REVme / D1.3, may be used to distinguish virtual APs from APs that are capable of communication.

[0324] Finally, in step 740, the AP MLD informs the non-AP MLD or STA of the virtual AP characteristics. In other words, the AP MLD transmits information about the affiliated virtual AP that defines the off-link (including the link ID) to the non-AP MLD. To this end, the AP MLD may transmit information in different frames depending on the event that has triggered the instantiation of the virtual AP and the type of information that the AP MLD wants to share with the STA.

[0325] Complete virtual AP features:

[0326] The AP MLD may include the virtual AP identification and characteristics as part of the multi-link element in the probe response frame 213 or in the beacon frame 211 or in the association response frame 215. Therefore, the virtual AP may be an additional STA with a dedicated per-STA profile in the link information 530. The per-STA profile corresponding to the virtual AP should contain information for distinguishing the virtual AP from other APs. For example, Figure 5b As illustrated, a new off-link field 560 may be included in the STA control field 533. When the link corresponding to the link ID is an off-link bound to a virtual AP that is not directly reachable, the off-link field is set to 1. The STA information field 534 may also include a usage mode subfield 561. The usage mode subfield 561 is a number that identifies the (recommended / restricted) usage of the link corresponding to the link ID carried in subfield 540. In a variation, if the off-link subfield 561 is set to 1, the usage mode field 561 may be conditionally present. The usage mode subfield may be associated with Figure 6 / Figure 6a / Figure 6b The subfield 630 represented in is the same. Figure 6aThe usage mode definition table 660 presented in FIG. 6 includes, in addition to existing values, new values ​​"3", "4", and "5" that can be used to specify link usage. A new value "3" 664 indicates that the link should be restricted to P2P communication, a value "4" 665 indicates that the link is dedicated to communication between APs, and a value "5" 666 indicates that the link is dedicated to coexistence with communication in another radio access technology, for example, a device embeds multiple communication chips (cellular, Wi-Fi, Bluetooth) and attempts to optimize the coexistence between these different radio access technologies. The usage mode definition can be a table independent of the table for the channel usage element to define, for example, Figure 5b In this table 570, a value of "0" 571 indicates that the link should be restricted to P2P communication, a value of "1" 572 indicates that the link is dedicated to communication between APs, and a value of "2" 573 indicates that the link is dedicated to low-latency communication.

[0327] In an alternative embodiment, the common information field 520 ( Fig.5a1 ) includes a new off-link bitmap or virtual AP bitmap subfield. Each bit in the off-link bitmap (or virtual AP bitmap) subfield included in the common information field 520 corresponds to a link, and the bit position i in the bitmap corresponds to the link with the link ID equal to i. The value in the bit position i in the bitmap corresponding to the following link is 1, otherwise the bit position is set to 0, where on the link, the STA attached to the non-AP MLD indicates that the link is an off-link or the AP corresponding to the link is a virtual AP. This variation may be of interest in order to improve the parsing of the per-STA profile element. Therefore, if the STA is not interested in the off-link / virtual AP function, the per-STA profile corresponding to the following link can be skipped, where the link is identified as an off-link or the AP corresponding to the link is a virtual AP.

[0328] Additionally, a per-STA configuration file may include all elements required to characterize a virtual AP.

[0329] In other words, information about the affiliated virtual APs is at least partially exchanged as part of the multilink element 500 in the probe response frame 213 or in the beacon frame 211 or in the association response frame 215, and wherein:

[0330] - the subordinate virtual AP is declared as an additional STA in the multilink element 500 using a dedicated per-STA profile sub-element 530, which contains information 560, 561 to distinguish the subordinate virtual AP from other subordinate APs of the AP MLD; or

[0331] - The common information field 520 of the multilink element 500 includes an off-link bitmap or virtual AP bitmap subfield.

[0332] Optionally, the non-inherited element appears as the last element in the STA profile field and carries a list of elements that the reported STA has not inherited from the reporting STA. In one embodiment, this element carries all element IDs corresponding to AP capabilities or operations (HE, EHT, QoS) that are useless in the virtual AP context. As an example, all capabilities or operating parameters (e.g., HT / HE / VHT / EHT capabilities or operations IE) that are typically used to describe a link for non-AP MLD operation should not be inherited by the reported virtual link / AP from the reporting STA: these elements are therefore specified in a non-inherited element that exists as the last element of the per-STA profile of the basic multi-link element. In another embodiment, the per-STA profile of the virtual AP is not subject to inheritance from the reporting STA and is defined only by the elements included in its per-STA profile. In other words, the per-STA profile can exclude all elements required to characterize communications on the virtual AP.

[0333] In other words, the per-STA profile sub-element 530 specific to the attached virtual AP:

[0334] - comprises: a non-inherited element carrying at least one of AP capabilities and operations that are not useful in the context of a virtual AP due to the fact that the virtual AP does not communicate in its basic service set (BSS); or

[0335] -Not subject to inheritance.

[0336] Virtual AP operation channel:

[0337] The AP MLD may also transmit a channel usage response frame including a channel usage element (upon receiving the channel usage request frame in step 710 or autonomously). New variations of the channel usage element may be envisioned to inform the STA on the (one or more) virtual AP operating channel (i.e., the (one or more) operating channel of the off-link). Thus, (refer to Figure 6a This new variation of the channel usage element (shown) includes a new field 650 at the end of the payload 600 that carries the link ID associated with the different channel entries 640. This field 650 may be Fig.5a1 The Link ID Information subfield 523 is presented in FIG. Figure 6b Another variation presented includes a link ID information subfield 643 as a new subfield of the channel entry field 640 .

[0338] refer to Figure 6a and Figure 6b Variations of the presented channel usage element may be included in the reporting AP ( Figure 8 In the probe response frame body of the AP1 in the example of , or to the reported AP ( Figure 8In the example of AP2), the multilink element is included in the per-STA configuration file. If (refer to Figure 6 , Figure 6a and Figure 6b ) channel usage element is included only in the frame body for the reporting AP, then the element may include channel usage information for all frequency bands (2.4 GHz, 5 GHz, and 6 GHz) supported by all APs attached to the AP MLD of the reporting AP. The reporting AP may optionally use a multi-band element (as defined in the multi-band element of IEEE802.11-REVme / D1.3 (June 2022), section 9.4.2.138) to advertise supported channels relative to other attached APs (reported APs). In another alternative, the channel usage element may be included in a common information field 520 of channel usage with the APMLD (including all attached APs). Otherwise, channel usage information may be advertised for each frequency band corresponding to the frequency bands of different APs attached to the AP MLD, thereby carrying the channel usage element in the frame body for the reporting AP and in the per-STA profile of the multi-link element for (one or more than one) reported APs, as described above. For example, if AP1 operates in the 2.4 GHz band, only channel usage corresponding to the 2.4 GHz band may be reported, and if AP2 operates in the 5 GHz band, only channel usage corresponding to the 5 GHz band may be reported.

[0339] In other words, the information about the subordinate virtual AP includes information about at least one off-channel of the AP MLD exchanged as the channel usage element 600, and the information includes:

[0340] Link ID Information field 650, which contains the link ID and is associated with all channel entries of channel entry field 640, or

[0341] The link ID information subfield 643 of the channel entry field 640, which contains the link ID and is associated with all channel entries of the channel entry field 640; and

[0342] This information is included in the probe response frame 213 or the channel use response frame 816 .

[0343] AP MLD can also use neighbor report elements or simplified neighbor report elements to convey partial or complete characteristics of virtual AP / link. Figure 9a and Figure 9b An example of the TBTT information field included in a simplified neighbor report element according to an embodiment of the present invention is presented in FIG.

[0344] Return to Fig. 9 ,exist Figure 7aIn the example of FIG. 1 , the beacon frame carrying the simplified neighbor report element will contain at least two information fields 920 corresponding to AP2 and AP3 (such as the reported APs). AP3 is a virtual AP. Now, in Figure 7b In the example of , the beacon frame carrying the simplified neighbor report element will contain at least three information fields 920 corresponding to AP2, AP3 and AP4 (such as reported APs). AP3 and AP4 are virtual APs. The value of the MLD ID field 941 can be different between AP2 and virtual AP3 and AP4.

[0345] exist Figure 9a In the first embodiment, MLD parameter field 940 includes a new off-link field 944. The off-link field is set to 1 when the link corresponding to the link ID carried in field 942 is an off-link bound to a virtual AP that is not directly reachable.

[0346] exist Figure 9b In the second embodiment of the present invention, the MLD parameter field 940 includes a new usage mode field 945. The usage mode field 945 is a number that identifies the usage of the link corresponding to the link ID carried in field 942. The value that identifies the usage of the link may depend on the IEEE P802.11-REVme / D1.3 version, which was released Figure 6a Table 660 or Figure 5b Table 570 or Figure 6 Table 9-265 presented in or any combination of the values ​​presented in those tables.

[0347] In other words, information about the affiliated virtual AP is exchanged at least in part as a portion of a neighbor report element or a simplified neighbor report element 910 included in the beacon frame 211, which portion is an off-link field 944 or a usage mode field 945 included in the MLD parameter subfield 940, and gives information related to the link corresponding to the content of the link ID field 942 also included in the MLD parameter subfield 940.

[0348] The third embodiment may be a combination of the previous two embodiments. In this case, the MLD parameter 940 includes an off-link field 944 and a use mode field 945. When the link corresponding to the link ID carried in field 942 is an off-link bound to a virtual AP that is not directly reachable, the off-link field is set to 1. The use mode field 945 is a number that identifies the use of the off-link corresponding to the link ID carried in field 942. The use mode element may exist only when the off-link field 944 is set to 1.

[0349] In a variation, the AP MLD may create a virtual AP based on an existing affiliated AP. For example, the AP MLD may demap all TIDs in the downlink and uplink on the link corresponding to the AP that the AP MLD wants to convert in the virtual AP. In addition, the AP MLD may map only some TIDs on the P2P TID to the link mapping for the link bound to the virtual AP.

[0350] Additionally, the virtual AP or off-link capability of the AP MLD may be reported to the non-AP MLDs through a new entry in the extended capability element (e.g., bit 90), or through a new subfield (e.g., one of the reserved bits) of the MLD capability and operation of the multilink element carried, for example, in the beacon frame 211 or the probe response frame 213 or the association response 215 or the reassociation response frame. This capability advertises to the non-AP MLDs that the AP MLD supports the virtual AP or off-link capability, and that although no off-link is currently available, the non-AP MLD(s) may also, for example, send a signal such as Figure 8b The channels described in use request frames to trigger the creation of an off-link.

[0351] Figure 7d Example operations of wireless communications by a non-AP MLD for TDLS setup on an off-link are illustrated in accordance with certain aspects of the present disclosure.

[0352] Operations may begin at step 750, where a non-AP MLD (e.g., 120) transmits a trigger to obtain an off-link, e.g., for P2P communication. The trigger may be a probe request frame 212 received from a non-AP MLD that has not yet been associated, the probe request frame 212 including off-link capabilities as new inputs (e.g., bit 90) in an extended capabilities element, and / or a channel usage element. It may be noted that an extended capabilities element including off-link capabilities may also be carried in an association request frame or a reassociation request frame in addition to in a probe request frame. After association, the non-AP MLD may request the setup of an off-link by sending a channel usage request to the APMLD. The channel usage request frame may include a legacy channel usage element such as that defined by IEEE P802.11-REVme / D1.3 or ( Figure 6a or Figure 6b In this variation, the link ID information field 650 may be set with a specific value requesting the AP MLD to allocate an off-link.

[0353] In step 760, the non-AP MLD receives information related to the AP MLD, either as a direct response to step 750, or based on an autonomous transmission by the AP MLD (eg, a beacon or an autonomous channel usage response frame).

[0354] In particular, the non-AP MLD obtains a link identifier ID that defines an off-link corresponding to at least one off-channel that does not overlap with the channel(s) used by the AP MLD.

[0355] Based on the received information, in step 770, similar to Figure 2 According to the process 210 described in the above, the non-AP MLD 120 initiates the multi-link setup with the AP MLD 110. The process relies on the exchange of association request 214 / response 215 frames, each of which includes a multi-link element. The multi-link element allows describing and selecting a set of candidate setup links between its own affiliated non-AP STAs and some discovered affiliated APs, and requests the AP MLD 110 to setup these links, which can be accepted or rejected by the AP MLD. In the present invention, if the non-AP MLD intends to use the off-link, the multi-link element transmitted in the association request 214 includes information of virtual APs (off-links) in addition to information of other APs (other links). This information can be used by the AP MLD to obtain some metrics about the use of the off-link, such as the number of non-AP MLDs that intend to use the off-link. Based on the metric, the AP MLD can further decide to instantiate a new virtual AP to support more P2P communications or to modify an existing virtual AP by expanding the operating band. Once the ML setup is complete, the AP MLD and non-AP MLD can communicate together over any setup link according to the TID-to-link mapping rules (except over an off-link, where the use of the off-link is restricted to, for example, P2P communication).

[0356] Then, in step 780, the non-AP MLD 120 performs TDLS setup with the off-link as the target link with the second non-AP MLD 130. In other words, the non-AP MLD uses the link ID as an indication of the off-link for the tunneled direct link setup (TDLS) direct link, and establishes a TDLS direct link between the first TDLS station STA attached to the non-AP MLD and the second TDLS STA through the channel (one or more than one) (and thus link) used by the AP device.

[0357] In a particular embodiment, establishing the TDLS direct link includes setting up the TDLS direct link using the link ID to define the off-link as a TDLS direct link.

[0358] The link ID is, for example: Figure 4a The contents of the BSSID field 401, or Fig.5a2 The contents of the Link ID field 540, or Figure 4c bits of the Link ID Bitmap field 491.

[0359] In a variation, step 780 may be performed in two consecutive steps. First, the non-AP MLD 120 performs a TDLS setup with the second non-AP MLD 130 on a link operated by an AP (not a virtual AP), and the two non-AP MLDs collect each other's supported channels. Then, for example, by using the TDLS channel switching process 230, the two non-AP MLDs move to an off-link corresponding to a mutually supported off-channel. Figure 8c This variation is further described.

[0360] In other words, in this variation, establishing a TDLS direct link includes:

[0361] - setting up an initial TDLS direct link that enables point-to-point communication between the first TDLS STA and the second TDLS STA; and

[0362] - Using the channel of the off-link as the target channel for the target link, or defining the off-link as the target link using the link ID, channel switching is performed to move the point-to-point communication from the initial TDLS direct link to the target link.

[0363] In a specific implementation of this variation (see below), the non-AP MLD disables or removes the initial TDLS direct link.

[0364] TDLS can be configured over any link (except off-link) with AP MLD configured. Figure 8 In the example of , the TDLS initiator STA A1 121 performs TDLS setup with the TDLS responder STA B1 131 via AP1 111. Each TDLS setup frame includes a link identifier 400. The TDLS initiator STA address field 402 carried in the link identifier is set with the MLD MAC address of the non-AP MLD 120, the TDLS responder STA address field 403 is set with the MLD MAC address of the non-AP MLD 130, and the BSSID field 401 is set with the BSSID corresponding to the off-link. In another variation, the off-link may be added in a per-STA profile carried in a TDLS multi-link element. The ML element transmitted by the TDLS initiator non-AP MLD in the TDSL setup request informs the peer non-AP MLD that the TDLS link(s) may be established. In response, the ML element transmitted by the TDLS responder non-AP MLD in the TDLS Setup Response informs the TDLS initiator non-AP MLD of the link(s) valid for establishing the TDLS session, ie, the accepted links.

[0365] In another variation, the TDLS setup frame includes a multilink link information element 490, which includes a link ID bitmap 491. When the multilink link information element 490 is transmitted in the TDLS setup request frame, the link ID bitmap 491 indicates the target link for the TDLS setup, and when the multilink link information element 490 is transmitted in the TDLS setup response frame, the link ID bitmap 491 indicates the accepted link. One bit in the link ID bitmap can correspond to an off-link of the present invention.

[0366] In other words, establishing a TDLS direct link includes at least one of the following operations:

[0367] - including a link identifier 400 in a TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA, the link identifier 400 including a basic service set identifier (BSSID) field set with a BSSID corresponding to the virtual AP and thus corresponding to the off-link;

[0368] - adding an off-link in the per-STA profile sub-element 530 carried in the TDLS multilink element 500 exchanged between the first TDLS STA and the second TDLS STA; and

[0369] - A multi-link link information element 490 including a link ID bitmap 491 indicating an off-link is included in a TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA.

[0370] As a result, if the TDLS setup is successful, STAs A3 123 and B3 133 (TDLS peer STAs) respectively attached to non-AP MLDs 120 and 130 can communicate on the off-link in step 790. In other words, the non-AP MLD operates point-to-point communication between the first TDLS STA and the second TDLS STA on the off-link.

[0371] It must be noted that the non-AP MLD may be on another link (e.g., Figure 7a and Figure 7b 151) in which communication with the AP device is operated.

[0372] Figure 8 The frame exchanges in the use timeline illustrate when the AP MLD notifies the TDLS initiator non-AP MLD that the off-link is available to handle P2P traffic. Figure 2 and Figure 2a scene. Figure 2 and Figure 2aThe same reference numerals in the drawings correspond to the same stages / steps / frames / entities.

[0373] At the beginning of the frame exchange, STA A1 121 attached to non-AP MLD 120 is not associated with any AP or AP MLD. In the context of multi-link discovery, STA A1 121 transmits a probe request frame 812 including a portion of the STA capabilities. With respect to the present invention, the probe request frame 812 includes a supported operation class element (sequence 6 in the probe request frame body) and a channel usage element (sequence 11 in the probe request frame body). If the reporting STA is attached to a non-AP MLD to advertise the operation class it is currently configured to operate, the STA or non-AP MLD uses the supported operation class element. The channel usage element includes a link ID information field ( Figure 6a 650 or Figure 6b 643 in the probe request frame). The link ID information subfield is set to a wildcard value requesting the AP MLD to allocate an off-link. The usage mode carried in the channel usage element advertises to the AP MLD the usage that the station wants to make with the off-link. The probe request also includes in its multi-link version a multi-link element that permits requesting information from the AP MLD. If there is no per-STA profile in the multi-link element, the AP MLD should include information about all of its affiliated APs, otherwise the AP MLD only advertises the non-AP MLD with the following per-STA profile, the link ID of which is equal to the value in the link ID field included in the per-STA profile carried in the multi-link element in the probe request frame. In another embodiment, the supported operation classes may be carried in a per-STA profile included in the multi-link element to advertise the operation class that each STA is currently configured to operate for each STA affiliated with the non-AP MLD. In addition, the STA control field of the probe request multi-link element may include a new subfield indicating that the per-STA profile is used for AP information, whereas typically the per-STA profile in the multi-link probe request identifies the AP for which information is requested.

[0374] In another embodiment, the non-AP MLD may advertise supported operation classes over different bands to the AP MLD using the multi-band element (sequence 14 in the probe request frame body). In effect, the multi-band element indicates that the STA transmitting the element (the transmitting STA) is within a multi-band device capable of operating in bands or operation classes or channels other than the band or operation class or channel in which the element was transmitted.

[0375] The target AP MLD 110 responds to the STAA1 121 with a probe response frame 813 through its subordinate AP1 111. The probe response frame includes one or more channel usage elements. The channel usage element should include a channel that is valid for the regulatory domain in which the AP transmitting the element is operating and consistent with the region element in the beacon or probe response frame; the channel usage element should not include any other channels. The channel usage element includes a link ID associated with a virtual AP that has been instantiated (step 720, if the AP MLD supports virtual AP or off-link capabilities) to create an off-link. The operating band assigned to the off-link depends on the supported operating classes collected from the non-AP MLDs and the operating band currently used by the AP MLD. As a reminder, the off-channel does not overlap with the (one or more) channels used by the access point. In addition, the AP MLD may further consider some non-simultaneous transmission and reception constraints. In an alternative embodiment, the probe response frame includes a traditional channel usage element. In this case, the probe response frame includes a multilink element with the virtual AP identity (i.e., link ID) and characteristics (at least operating class / band / channel) in a dedicated per-STA profile in addition to the per-STA profiles for other requested APs. Figure 5b The per-STA profile of the STA includes an off-link subfield 560 and / or a usage mode subfield 561. In another embodiment, information related to virtual AP identification and usage is included in a STA such as Figure 9a and Figure 9b The usage mode in different aforementioned variants is set to a value that restricts usage to P2P communication (e.g. Figure 6a The value in 3).

[0376] Upon receiving the probe response frame 813, the non-AP MLD 120 may attempt to associate with the AP MLD 110. The non-AP MLD 120 transmits an association request frame 214 via STA A1 111, the association request frame 214 including a multilink element having a per-STA profile for each link (corresponding to each AP attached to the AP MLD) to which the non-AP MLD requests association. A virtual AP may be added as a requested AP in the per-STA profile to inform the AP MLD that the non-AP MLD will use an off-link.

[0377] If the AP MLD agrees to the association request, the AP MLD 110 responds to the non-AP MLD 120 with an association response frame 215. The association response frame includes a per-STA profile for each link corresponding to each AP of the AP MLD that was accepted for association. Links corresponding to virtual APs should always be accepted.

[0378] If the off-link is dedicated to P2P communication, then the non-AP MLD 120 may decide to establish a TDLS setup targeting the off-link. Figure 2a The process 220 is described.

[0379] The TDLS initiator STA A1 121 performs TDLS discovery and TDLS setup with the TDLS responder STA B1 131 via AP1 111. Each TDLS discovery frame and setup frame includes a link identifier 400. The TDLS initiator STA address field 402 carried in the link identifier is set with the MLD MAC address of the non-AP MLD 120, the TDLS responder STA address field 403 is set with the MLD MAC address of the non-AP MLD 130, and the BSSID field 401 is set with the BSSID corresponding to the off-link.

[0380] In another variation, the off-link may be added in a per-STA profile carried in a TDLS multilink element. The multilink element transmitted by the TDLS initiator non-AP MLD in the TDSL discovery request frame 221 informs the peer non-AP MLD of the link(s) that can discover TDLS. In response, the multilink element transmitted by the TDLS responder non-AP MLD in the TDLS discovery response frame 222 informs the TDLS initiator non-AP MLD of the link(s) that it can operate on.

[0381] The multilink element transmitted by the TDLS initiator non-AP MLD 120 in the TDSL setup request frame 223 through STAA1 121 informs the peer non-AP MLD 130 of the link(s) that can establish the TDLS. In response, the multilink element transmitted by the TDLS responder non-AP MLD 130 in the TDLS setup response frame 224 through its subordinate station STAB1 131 informs the TDLS initiator non-AP MLD of the link(s) that will effectively establish the TDLS session, i.e., the accepted link. The multilink element transmitted by the TDLS initiator non-AP MLD 120 in the TDSL setup confirmation frame 225 through STAA1 121 informs the peer non-AP MLD 130 of the link(s) that establish the TDLS session.

[0382] In another variation, the TDLS setup frame includes a multilink link information element 490, which includes a link ID bitmap 491. When the multilink link information element 490 is transmitted in the TDLS setup request frame 223, the link ID bitmap 491 indicates the target link for the TDLS setup, and when the multilink link information element 490 is transmitted in the TDLS setup response frame 224, the link ID bitmap 491 indicates the accepted link. One bit in the link ID bitmap may correspond to an off-link of the present invention.

[0383] Then, when the TDLS session is established, the peer non-AP MLD may communicate P2P data traffic 226 directly with its dedicated subordinate stations (STA A3 123 subordinate to non-AP MLD 120 and STAB3 133 subordinate to non-AP MLD 130, respectively) over the off-link 173. Each non-AP MLD may continue to operate with the AP MLD using other (one or more) setup links.

[0384] Figure 8b The frame exchanges in the usage timeline illustrate when a non-AP MLD that has been associated with an AP MLD requests the creation of an off-link for P2P traffic through a channel usage request frame. Figure 2 and Figure 2a scene.

[0385] In the example of the figure, no off-links are created and used during the association with the AP MLD. The non-AP MLD 120 requests the AP MLD 110 to create a P2P off-link, for example to answer a new application requirement.

[0386] The non-AP MLD 120 transmits a channel use request frame 815 to the AP MLD 110 via the STA A1 121 .

[0387] refer to Figure 6c Describes the channel usage request frame. The frame mainly includes a channel usage element field 681 and a supported operation class element field 682. The WNM field 680 defines the type of the frame, namely, a channel usage request frame.

[0388] The Channel Usage Element field includes one or more channel usage elements that identify the requested usage mode. Figure 6 , Figure 6a and Figure 6b The channel usage element is described in . The channel usage element includes a link ID information field ( Figure 6a 650 or Figure 6b 643 in FIG. 643). The Link ID Information subfield is set to a wildcard value for requesting the AP MLD to allocate a link.

[0389] The Supported Operation Classes Element field contains Supported Operation Classes elements consistent with the Region elements advertised by the AP to indicate the supported operation classes for the requested network type.

[0390] In the alternative, frame 815 may be a new off-link creation request frame identified by a new value in the NWM field (WNM Action field value set to 28), the new off-link creation request frame having the same elements but without the Link ID field in the Channel Use element.

[0391] Upon receiving the channel use request frame 815, the AP MLD executes steps 720 and 730 to create a dedicated channel for Figure 8b The off-link of the P2P communication in the example. Then, the AP MLD 110 responds to the non-AP MLD 120 via AP1 111 with a channel usage response frame 816. Similar to the channel usage request frame, the channel usage response frame includes an NWM field 680 and a channel usage element field 681. The channel usage element includes a link ID associated with a virtual AP that has been instantiated (step 720, if the AP MLD supports virtual AP or off-link capabilities) to create an off-link. The operating band assigned to the off-link depends on the supported operating classes collected from the non-AP MLD and the operating band currently used by the AP MLD. As a reminder, the off-channel does not overlap with the (one or more than one) channel used by the access point. In addition, the AP MLD may further consider some non-simultaneous transmission and reception constraints. Other fields are not within the scope of the present invention.

[0392] In a variation, frame 816 may be a new off-link creation response frame identified by a new value in the NWM field (WNM Action field value is set to 29) having the same elements as in the Channel Use Response frame.

[0393] Once AP MLD 120 creates the off-link, AP MLD 120 may advertise to all surrounding stations by including the virtual AP / off-link characteristics in beacon frame 211. Beacon frame 211 includes a variation on the simplified neighbor report and multi-link elements described in the previous figures.

[0394] The rest of the frame exchange is similar to Figure 8 The frame exchange described in .

[0395] Figure 8c The frame exchanges in the timeline illustrate when a non-AP MLD that has associated with an AP MLD (the association includes such Figure 8 When a TDLS setup is performed on a link shared with an AP and moves to an off-link by using TDLS channel switching, Figure 2 and Figure 2aThe figure involves Figure 7b An 802.11 network environment in which a non-AP MLD has two subordinate STAs, one dedicated to P2P communication and the other dedicated to communication with the AP MLD.

[0396] The process 820 corresponding to the multilink setup with AP MLD, including the off-link in the multilink element comprises: Figure 8 The process is performed between the non-AP MLD 120 and the AP MLD 110 and also between the non-AP MLD 130 and the AP MLD 110. Therefore, the non-AP MLDs 120 and 130 are associated with the AP MLD 110 and have knowledge of the off-link dedicated to P2P communication.

[0397] The TDLS initiator STA A2 122 performs TDLS discovery and TDLS setup with the TDLS responder STA B2 132 via AP2 112. Each TDLS discovery and setup frame includes a link identifier 400. The TDLS initiator STA address field 402 carried in the link identifier is set with the MLD MAC address of the non-AP MLD 120, and the TDLS responder STA address field 403 is set with the MLD MAC address of the non-AP MLD 130, but is different from the MLD MAC address of the non-AP MLD 130. Figure 8 In contrast, the BSSID field 401 is set with a BSSID corresponding to a normal AP (not a virtual AP) operating on the basic channel. The AP is associated with the STA (AP2 in the example of this figure) that will be used for further P2P communication. The TDLS setup frame allows the sharing of supported channel elements between the two TDLS peer STAs, thereby confirming that they support off-links operating on (one or more than one) off-channels.

[0398] Then, TDLS initiator STA A2 transmits TDLS channel switching request frame 231 to move P2P communication to the off-link. The TDLS channel switching request includes a link identifier 400, a target channel and its operation class, and timing information for channel switching, such as defined in the TDLS setting. The target channel corresponds to the operating channel of the off-link (i.e., the off-channel). In addition, the off-link channel used as the target channel can be the basic channel of the off-link or the main channel of the off-link or one of the channels in the channel entry (channel usage element) corresponding to the off-link. The target partner STAB2 responds with a TDLS channel switching response frame 232 in which the link identifier and status code are set to success (if the target partner STAB2 agrees to switch to the target channel), and then both peer STAs switch to the target channel (from the basic channel). If the TDLS channel switching response frame 232 contains a status code different from success, the two STAs continue to operate on the current basic channel.

[0399] We now describe some variations where the channel switch indicates a target link instead of a target channel.

[0400] In a first variation, the non-AP MLD infers that this is a link switch because the target channel corresponds to an off-link created by the AP MLD.

[0401] In a second variation, we use the link identifier included in the channel switch to indicate the target link by its BSSID for the setup. Therefore, the BSSID field 401 of the link identifier 400 is set to the BSSID of the virtual AP corresponding to the off-link. In addition, the TDLS initiator STA address field 402 and the TDLS responder STA address field 403 can be set to the address of the STA involved in the switch (instead of the address of the MLD). Figure 8c In the example of , we obtain: the TDLS initiator STA address field is set to the address of STA A2 122; the TDLS responder STA address field is set to the address of STA B2 132; and the BSSID field is set to the BSSID of AP3 113 corresponding to the off-link.

[0402] In a third variation, we add a link ID field in the channel switch request / response frame.

[0403] The first and second variations allow existing signaling to be maintained.

[0404] In order to avoid being forced to switch back to the basic channel, the non-AP MLD 120 and 130 must disable or remove the link (referred to as the "previous link") previously used by AP2112 to communicate with STA A2 122 and STA B2 132. This can be done by removing all TIDs from the previous link and thus disabling the previous link, or by (re)setting up the multilink between the AP MLD 110 and the non-AP MLD 120 and 130 to remove the previous link from (one or more than one) setup links to update the TID to link mapping. The arrow 850 in this figure represents the process of link removal or disabling. In the example of the figure, when link removal / disabling is performed after TDLS channel switching, a message corresponding to the process is transmitted by STA A1 121 and STA B1 131, but in an alternative, STA A2 and STA B2 can transmit the message before performing the TDLS channel switching.

[0405] Therefore, after the removal / disability of the previous link, both STAs (STA A2 and STA B2) are dedicated to P2P communication and can conduct direct link communication on the off-link without switching back to the basic channel.

[0406] Relying on a virtual AP involves additional processing for the AP MLD, such as additional signaling in management frames. Other mechanisms are provided below. In these mechanisms, one of the (peer) non-AP MLDs creates a TDLS link with its own link ID, which defines an off-link corresponding to at least one off-channel that does not overlap with the channel (one or more) used by the AP device. Then, a TDLS direct link can be established between non-AP MLDs using this TDLS link (i.e., its link ID) using conventional TDLS mechanisms.

[0407] Advantageously, the AP MLD is not involved in the creation process. However, in order to efficiently select one or more off-channels that do not affect the operation of the AP MLD, the non-AP MLD may obtain a recommended channel from the AP MLD that is not an infrastructure BSS or an off-channel TDLS direct link. One or more off-channels for defining the off-link are then selected from the recommended channels.

[0408] refer to Figures 11a to 11d A first embodiment is described. In these embodiments, a TDLS link is created by exchanging TDLS action frames with other (peer) non-AP MLDs. Such frames may be new TDLS action frames compared to the D2.2 standard. As TDLS action frames, they are tunneled by the AP device to simultaneously create an off-link at the two (peer) non-AP MLDs.

[0409] Then, the establishment of the TDLS direct link between the two non-AP MLDs is only to perform a TDLS direct link establishment with the created off-link as the target. Conventional TDLS direct link establishment is defined in Section 11.20.4 of IEEE P802.11-REVme / D2.0. Figure 2a As illustrated, conventional TDLS direct link establishment includes exchanging TDLS Setup Request / Response frames, where these frames include (eg, in Link Identifier IE 400) the MAC address of the affiliated peer STA associated with the created off-link.

[0410] Fig.11a An 802.11 network environment involving non-AP multi-radio devices MLDs associated with AP devices in which embodiments of the present invention may be implemented is illustrated. The example of the figure illustrates two non-AP MLDs (non-AP MLD A 120 and non-AP MLD B 130) with two subordinate STAs (from 121 to 122 and from 131 to 132, respectively) and an APMLD 1101 with only one subordinate AP 111. In another embodiment, AP 1101 may be a conventional AP, i.e., without any multi-link capability. Each non-AP MLD has already set up a link with an AP device, where STA A1 121 has a set up link 151 with AP1 111, and STA B1 131 has a set up link 161 with AP1 111.

[0411] The non-AP MLDs 120 and 130 instantiate or create TDLS links on a set of (one or more) off-channels (which do not overlap with the operating channels of the AP device) to obtain an off-link 172 for operations other than AP management. The created TDLS link or off-link 172 is set at another subordinate station (here, STA A2 122 for non-AP MLD A 120 and STA B2 132 for non-AP MLD B 130) other than the transmission station.

[0412] Typically, this off-link is used for TDLS communication. This means that the non-AP MLDs 120 and 130 establish a TDLS session (TDLS direct link) on the off-link 172 by exchanging TDLS action frames via their subordinate stations STA A1 121 and STA B1 131, which are tunneled by AP1 111.

[0413] Thus, the non-AP MLDs 120 and 130 are able to use the off-link 172 with one of its affiliated stations while maintaining the previous connection with the AP device through the initial link corresponding to the connection with AP1 111.

[0414] Of course, for purposes of illustration, the number of links shown in this figure is not limiting.

[0415] Fig.11b Exemplary steps for direct communication according to certain aspects of the present invention are illustrated using a flow chart. These steps are performed by a (peer) non-AP MLD that initiates the creation or instantiation of a TDLS link (off-link) on a set of (one or more than one) off-channels.

[0416] Operation begins at step 1210, where the TDLS initiator non-AP MLD obtains a recommended channel from the AP device that is not an infrastructure BSS or an off-channel TDLS direct link. For example, the TDLS initiator non-AP MLD may receive the recommended channel from AP1 as described above with reference to Figure 6 Describes the channel usage information.

[0417] Once a non-AP MLD (and its affiliated STAs) associates with an AP MLD, the channel usage information may be carried in the probe response frames exchanged during the association process with the AP MLD, or in the channel usage response frames exchanged with the AP MLD. The channel usage information is provided by the AP MLD to the TDLS initiator non-AP MLD to recommend a channel for a BSS that is not an infrastructure BSS or an off-channel TDLS direct link. The non-AP MLD may use the channel usage information as part of the channel selection process for a BSS that is not an infrastructure BSS or an off-channel TDLS direct link (4.3.21.4 Channel Usage in REVme 2.0 (October 2022)). In other words, the channel usage information provides the TDLS initiator non-AP MLD with a channel that does not overlap with the operating channel of the AP MLD.

[0418] Fig.11c The creation and use of an off-link according to an embodiment of the present invention is illustrated using frame exchanges in a timeline, where channel usage information is obtained from a probe response frame. This diagram is based on STA A1 121 and STA B1 131 registering with AP1 111. Fig.11a of the scene.

[0419] At the beginning of the frame exchange, STA A1 121 attached to non-AP MLD 120 is not associated with any AP or AP MLD. In the context of discovery, STA A1 121 sends a probe request frame 212 including STA capabilities. Of interest to the current scenario, the probe request frame 212 includes a supported operation class element (sequence 6 in the probe request frame body) and a channel usage element (sequence 11 in the probe request frame body).

[0420] The Supported Operation Classes element advertises the operation class that the non-AP MLD is currently configured to operate in. The Usage Modes carried in the ChannelUsage element advertises the usage that the non-AP MLD wishes to make with the off-channel(s).

[0421] In some embodiments, the probe request frame 212 is in a multilink version (802.11be), which means that the frame also includes a multilink element (defined in section 9.4.2.312.1 of the D2.2 standard) for requesting additional information from the AP MLD. If no per-STA profile is present in the multilink element, the AP MLD includes (in its probe response frame) information about all of its affiliated APs, otherwise the AP MLD only advertises non-AP MLDs with a per-STA profile whose link ID is equal to the value in the Link ID field included in the per-STA profile carried in the multilink element of the probe request frame.

[0422] In another embodiment, the supported operation classes may be carried in a per-STA configuration file included in a multi-link element to advertise, for each STA attached to a non-AP MLD, the operation class that each STA is currently configured to operate.

[0423] In yet another embodiment, the non-AP MLD uses the multi-band element (sequence 14 in the probe request frame body) to advertise supported operating classes over different bands to the APMLD. In effect, the multi-band element indicates that the STA transmitting the element (the transmitting STA) is within a multi-band device capable of operating in a band or operating class or channel different from the band or operating class or channel in which the element (probe request frame 212) was transmitted.

[0424] The AP MLD 1101 responds to the transmitting STA A 1121 with a probe response frame 213 through its subordinate AP1 111. The probe response frame 213 includes one or more channel usage elements as described above. These elements provide recommended channels (a set of channels for operation of a non-infrastructure network or off-channel TDLS direct link) that do not overlap with the channel(s) used by the AP MLD.

[0425] Upon receiving the probe response frame 213, the non-AP MLD 120 solicits association with the AP MLD (through its subordinate AP1 111). To this end, the non-AP MLD 120 transmits an association request frame 214 via STA A1 111. The association request frame 214 includes a multilink element having a per-STA profile for each link (corresponding to each AP subordinate to the AP MLD) for which association is requested by the non-AP MLD. Of course, when the AP 1101 is a traditional AP without multilink capability, such a multilink element does not populate the association request frame 214.

[0426] If the AP MLD approves the association request, then AP1 111 responds to the non-AP MLD 120 with an association response frame 215 that (only if the AP is an MLD AP) includes a per-STA profile for each link corresponding to each AP affiliated with the AP MLD that was accepted for association.

[0427] Fig.11d The creation and use of an off-link according to another embodiment of the present invention is illustrated using frame exchanges in a timeline, where once a non-AP MLD (its subordinate STA) associates with an AP MLD, channel usage information is obtained from a channel usage response frame exchanged with the AP MLD. This figure is based on the fact that STA A1 121 and STA B1 131 have registered with AP1 111. Fig.11a scene.

[0428] A non-AP STA supporting channel usage may send a channel usage request frame at virtually any time after associating to an AP supporting channel usage to request channel usage information for a supported operation class.

[0429] In this example, non-AP MLDs 120 and 130 have been associated to AP 1101. Therefore, non-AP MLD 120 requests channel usage information from AP MLD by sending a channel usage request frame 815. AP MLD replies with a channel usage response frame 816 including the channel usage information.

[0430] Return to Fig.11b Optionally, at step 1220, the TDLS initiator non-AP MLD performs a TDLS discovery process (as described above) to obtain information about the channel(s) and frequency band(s) supported by its peer non-AP MLD. This step includes sending the TDLS discovery process as described above. Figure 2a The TDLS discovery request frame 221 and the reception of the TDLS discovery response frame 222 have been described.

[0431] This optional step is Fig.11cand Fig.11d is exemplified in the scenario.

[0432] When attempting to discover a TDLS station in the same BSS, a series of frame exchanges are used.

[0433] The initiator STA A1 sends a TDLS discovery request frame 221 tunneled through AP1 111 (a relay illustrated by a black dot) to a single destination station, here the peer STA B1. The TDLS discovery request frame includes Figure 4a 400, and may also contain a multi-band element as defined above to indicate that the STA transmitting the element is within a multi-band device capable of operating in a frequency band or operating class or channel different from the frequency band or operating class or channel in which the element is transmitted. In addition, the STA informs the transmitting STA of the role it plays on the channel of the operating class indicated in the multi-band element (e.g., TDLS STA). The multi-band element allows the initiating STA to inform the receiving STA of its channel capabilities. Finally, the TDLS discovery request frame may contain the following: Figure 4b The TDLS multi-link element 450 is shown to, for example, convey the per-STA profile of each STA of the TDLS initiator non-AP MLD (here, non-AP MLD A120) and inform the channel capabilities supported by the non-AP MLD.

[0434] The peer STA B1 responds to the TDLS discovery request frame 221 with a TDLS discovery response frame 222 sent directly (without relaying by the AP 111) to the STA A1. The response frame conveys the link identifier element 400 and the TDLS multilink element 450 in the IE of the element field 303. In addition, the TDLS discovery response frame may include supported channels and multi-band elements to inform the TDLS initiator non-AP MLD of the channels and bands supported by the peer non-AP MLD through its subordinate STAs.

[0435] From this point on, STA A1 and STA Bl are aware of each other, which means they know that the other is operating on a communication link set up with AP 111. Also, from the MLD's point of view, both non-AP MLDs 120 and 130 are aware of the other's supported channels.

[0436] Next, the TDLS initiator non-AP MLD selects one or more channels as off-channels based on the recommended channels collected from the AP MLDs and optionally based on the supported channels / bands collected from the peer non-AP MLDs and its own supported channels / bands at step 1230. This means that the TDLS initiator non-AP MLD selects one or more of the recommended channels that match its supported channels / bands and the supported channels / bands of the peer non-AP MLDs.

[0437] The selected one or more channels may be on the same frequency band as the operating frequency band(s) of the AP MLD or on a frequency band different from the operating frequency band(s) of the AP MLD.

[0438] Then, a TDLS link targeting the selected set of off-channels is created by exchanging TDLS action frames tunneled by the AP MLD with the peer non-AP MLD. Thus, off-links for TDLS communication are simultaneously created at the two peer non-AP MLDs.

[0439] A new type of TDLS action frame, hereinafter referred to as a TDLS link setup request frame and a corresponding TDLS link setup response frame and a TDLS link setup confirmation frame, can be used in the same scheme as the TDLS setup frame. Of course, the TDLS setup frame can be upgraded to convey the signaling required for the TDLS link setup frame (rather than creating a new frame) described now.

[0440] The TDLS link setup request frame may be assigned a value of 11 in the action field 302 ; the TDLS link setup response frame may be assigned a value of 12 in the action field 302 ; and the TDLS link setup confirm frame may be assigned a value of 13 in the action field 302 .

[0441] For example, the TDLS initiator non-AP MLD initiates the creation of a TDLS off-link by sending a TDLS link setup request frame to a peer non-AP STA, the TDLS link setup request frame including a link identifier and an operating band of the new link, ie, the selected one or more off-links.

[0442] The TDLS link setup request frame may be a TDLS action frame, which includes:

[0443] A TargetChannel element (as defined in 9.4.1.35 (TargetChannel) of REVme 2.0) that specifies the channel number of the selected off-channel(s) for which the off-link is to be created,

[0444] An Operation Class element (as defined in 9.4.1.36 (Operation Classes) of REVme 2.0) that specifies the operating band of the off-link to be created, and

[0445] Link ID (i.e., numeric value) that identifies the off-link to be created in the future. Link ID elements can be used, such as Fig.5a1 Element 523.

[0446] The link ID (hereinafter also the TDLS link ID) is selected by the TDLS initiator non-AP MLD. Preferably, the TDLS link ID defining the off-link is selected from a set of candidate link IDs deprived of any link ID used by the AP MLD. This is to avoid any conflicts.

[0447] For example, the value of the TDLS link ID is outside the range of values ​​managed by the AP MLD, ie, higher than 15. In fact, therefore, the TDLS link ID is compatible with the link ID managed by the AP.

[0448] As a variation, the TDLS link setup request frame may include a link identifier element (eg, Figure 4a For example, the TDLS initiator non-AP MLD can specify the affiliated STA ( Fig.11a In the example of TDLS initiator non-AP MLD, the MAC address of the off-link is set to the MAC address of the STA A2). In particular, the MAC address is included in the BSSID field 401 to identify the target link, i.e., the off-link to be created. In this case, a BSSID (i.e., a basic service set identifier) ​​is assigned to the off-link, and the BSSID is set to the MAC address of the affiliated STA (here, STA A2) involved in the TDLS initiator non-AP MLD. In a variant, the BSSID of the off-link can be set to the MAC address of the TDLS initiator non-AP MLD.

[0449] The MAC address can be used as a single identification of the off-link. In a variant, the MAC address can be used in combination with the aforementioned link ID specified in element 523.

[0450] In some embodiments seeking to declare multiple off-links for a TDLS initiator non-AP MLD, the TDLS link setup request frame may include a multi-link element with multiple per-STA profiles, each per-STA profile conveying the target channel, operation class, and link identifier of the corresponding off-link to be created. This allows multiple off-links to be created with a peer non-AP STA through a single process (a single exchange of TDLS link setup request / response and confirmation frames).

[0451] In response, the TDLS initiator non-AP MLD receives a TDLS link setup response frame intended to confirm or not confirm the creation of the (one or more than one) off-link by using a dedicated code.

[0452] The TDLS link setup response frame may have the same format as the TDLS link setup request frame (plus a response code).

[0453] When a rejection code is communicated, the TDLS link setup response frame may reject the creation of the off-link (or multiple off-links).

[0454] In some embodiments, the TDLS link setup response frame includes an alternative off-link (or multiple off-links with multi-link elements) corresponding to at least one alternative off-channel that does not overlap with the channel (one or more than one) used by the AP device. This means that the peer non-AP MLD that does not accept the proposed off-link makes a counter-proposal. Therefore, the negotiation of the off-link is performed.

[0455] Alternative off-links may be defined with different operating frequency bands / channels.

[0456] Negotiation may continue as follows.

[0457] If multiple alternative off-channels are proposed, the TDLS initiator non-AP MLD may select one of them as the new target channel.

[0458] The TDLS initiator non-AP MLD then (with the initiator's consent) restarts the TDLS off-link creation process (sending a TDLS Link Setup Request frame) using the new target channel suggested by the peer non-AP MLD. In a variation, a TDLS Link Setup Confirmation frame as described below may be used to confirm the TDLS link creation using alternative parameters (primarily (one or more than one) operating channel) provided by the peer non-AP MLD via a TDLS Link Setup Response frame.

[0459] Of course, in a variation, the TDLS Link Setup Response frame may simply be a rejection without any suggestion for an alternative off-link.

[0460] Finally, if the link proposed in the TDLS Link Setup Request frame is approved by the peer non-AP MLD, the TDLS Link Setup Response frame accepts the creation of the off-link (or off-links) with an Accept code.

[0461] Then, the TDLS initiator non-AP MLD may send a TDLS link setup confirmation frame to confirm the creation of the link.

[0462] Note that at any time, once the off-link has been created, the TDLS initiator non-AP MLD (and / or peer non-AP MLD) can inform the AP MLD of the created link ID and the created off-link. This can be done by using the reserved bit 523b in any subsequent frame including the link ID information field 523.

[0463] exist Fig.11c and Fig.11d The creation of an off-link is illustrated in the same manner in FIG. 1301 shows a TDLS link setup request frame, 1302 shows a TDLS link setup response frame, and 1303 shows a TDLS link setup confirmation frame.

[0464] In detail, the TDLS initiator non-AP MLD A 120 sends a TDLS link setup request frame 1301 to the peer non-AP MLD B 130 (through its subordinate STA B1 131) on the existing link with the AP MLD (here, AP1 111) through its subordinate STA A1 121. The frame includes the target operating band and the channel on which the link must be established, as well as a link identifier for identifying the TDLS link or off-link to be created and the MAC address of the STA A2 122 subordinate to the non-AP MLD to be used for operating on the off-link. The MAC address can be used on behalf of the BSSID for the off-link.

[0465] In response to the TDLS link setup request frame 1301, the peer non-AP MLD responds to the initiator non-AP MLD via its subordinate STA B 1131 with a TDLS link setup response frame 1302. This frame includes the TDLS link ID received via frame 1301 plus a status code (accepted or rejected) to inform whether the creation of the link is accepted. In the case of link creation rejection, STA B 1131 adds one or more alternative frequency bands and / or channels in the response frame 1302.

[0466] When frames 1301 and 1302 include a multilink element with one or more per-STA profiles, link-level acceptance may be performed. Each STA profile communicated in the TDLS link setup request frame targets a different TDLS link or off-link to be created. And in response, each STA profile communicated in the TDLS link setup response frame corresponds to a TDLS link accepted by the peer non-AP STA. Other TDLS links are rejected.

[0467] Finally, the TDLS initiator non-AP MLD transmits a TDLS link setup confirm frame 1303 through its subordinate STAA1 121 to confirm the reception of the TDLS link setup response frame 1302. The TDLS link setup confirm frame 1303 conveys the link ID of the created off-link.

[0468] The TDLS Link Setup Confirmation frame allows sharing of the MAC addresses of STAs attached to the initiating non-AP MLD to operate on various different created off-link(s) (in a multi-link element if present).

[0469] As a result, a TDLS link is created, ie, an off-link.

[0470] Once the off-link is created, the TDLS initiator non-AP MLD initiates a TDLS direct link setup at step 1240 to setup a TDLS direct link with a second non-AP MLD (the target is the off-link). This can be done using conventional TDLS setup frames 223, 224, 225, wherein each TDLS setup frame includes a link identifier 400 in which a BSSID field 401 is set to the MAC address of the STA affiliated with the initiator non-AP MLD that will operate on the target link. This is to indicate which off-link the TDLS setup is targeting. In some embodiments, a TDLS peer key (TPK) security protocol is derived based on the BSSID included in the link identifier corresponding to the STA affiliated with the TDLS initiator non-AP MLD that intends to operate on the off-link ( Fig.11a In the example of STAA2).

[0471] In a variation where the off-link is signaled in the BSSID field 401, the target off-link may be specified in a per-STA profile carried in the TDLS multilink element 450. The multilink element transmitted by the TDLS initiator non-AP MLD in the TDLS setup request frame 223 informs the peer non-AP MLD that the TDLS link(s) may be established. In response, the multilink element received by the TDLS initiator non-AP MLD from the peer non-AP MLD in the TDLS setup response frame 224 informs the TDLS initiator non-AP MLD that the link(s) for the TDLS session may be effectively established, i.e., about the accepted off-links. In this variation, the BSSID field 401 may be set to the MAC address of the BSSID corresponding to the BSS of which the TDLS initiator non-AP MLD is a member, i.e., the MAC address of the AP 111 or the AP MLD 1101. In case of establishing a TDLS session for multiple links (only off-link or several classic direct links (with shared operating band with AP) or a mix of classic and off-link), the TDLS peer may create its own group TPK key for multiple links. Since each subordinate STA of the MLD uses a different MAC address, the key creation process may be adapted. Several variants may be envisaged:

[0472] (1) The TDLS PeerKey (TPK) security protocol can be derived based on the BSSIDs of all links set up by the TDLS setup process. These BSSIDs can be retrieved from the per-STA configuration file of the multi-link element. The BSSID corresponds to the AP MAC address for the classic link and to the address of the TDLS STA (initiator or responder) for the off-link. When the frames transmitted by the two peers during the TPK handshake include the TDLS multi-link element and are set up for several links including (one or more than one) off-link, the TPK can be derived as follows:

[0473] TPK=KDF-Hash-Length(TPK-Key-Input,“TDLS PMK”,min(MAC_I,MAC_R)||max(MAC_I,MAC_R)||BSSID1||BSSID2||…BSSIDn||AP MLD MAC)

[0474] in:

[0475] TPK-Key-Input is derived from the hash algorithm, and KDF-Hash-Length is the key derivation function, as defined in section 12.7.1.6.2 of REVme D2.0;

[0476] MAC_I and MAC_R are the MAC addresses of the TDLS initiator STA and the TDLS responder STA respectively;

[0477] The n listed BSSIDs are set to the BSSIDs of the BSS of which the TDLS initiator STA is a member;

[0478] AP MLD MAC is the MLD MAC address of the AP MLD with which the initiating non-AP MLD performs multilink setup.

[0479] In the event that the number of links in a TDLS session is modified, the TDLS peers may decide to still use the current TPK throughout its (but limited) lifetime, and upon reaching the end of the lifetime, update the TPK by taking into account the new (modified) set of links and their associated BSSIDs.

[0480] (2) In a variation, a TDLS peer key (TPK) may be derived based on the BSSID of one of the links, or based on a wildcard BSSID, or based on a BSSID corresponding to a BSS of which the TDLS initiator non-AP MLD is a member (i.e., the MAC address of AP 111 or AP MLD 1101). The TPK may be derived as follows:

[0481] TPK=KDF-Hash-Length(TPK-Key-Input,“TDLS PMK”,min(MAC_I,MAC_R)||max(MAC_I,MAC_R)||BSSID||AP MLD MAC)

[0482] In addition to the above parameters defined above:

[0483] The BSSID is the BSSID of the BSS of which the TDLS initiator STA is a member.

[0484] (3) In another variation, a TDLS peer key (TPK) may be derived based on the non-AP MLD and AP MLD MAC addresses without regard to the BSSID(s) corresponding to the link(s) used. The TPK may be derived as follows:

[0485] TPK=KDF-Hash-Length(TPK-Key-Input,“TDLS PMK”,min(MLD MAC_I,MLD MAC_R)||max(MLD MAC_I,MLD MAC_R)||AP MLD MAC)

[0486] In addition to the above parameters defined above:

[0487] MLD MAC_I and MLD MAC_R are the MLD MAC addresses of the (non-AP) TDLS initiator MLD STA and the (non-AP) TDLS responder MLD STA, respectively.

[0488] (4) In yet another variation, if a non-AP MLD is associated with a traditional AP (e.g. Fig.11a 111 in the example of ), then the TDLS peer key (TPK) can be derived based on the non-AP MLD MAC address and the BSSID of the BSS of which the TDLS initiator STA is a member. The TPK can be derived as follows:

[0489] TPK=KDF-Hash-Length(TPK-Key-Input, "TDLS PMK", min(MLD MAC_I, MLD MAC_R)||max(MLD MAC_I, MLD MAC_R)||BSSID).

[0490] Variants (2), (3) and (4) advantageously allow the number of links in a TDLS session to be modified without modifying the TPK.

[0491] Any combination of TPK variations is contemplated.

[0492] In another variation of the signaling of the off-link described above, the TDLS setup frame includes a multilink link element 490, which contains a link ID bitmap 491, and each bit of the link ID bitmap 491 corresponds to a previously created off-link. The link ID bitmap 491 in the TDLS setup request frame 223 indicates the target off-link for TDLS setup, and the link ID bitmap 491 in the TDLS setup response frame 224 indicates the accepted (one or more than one) off-link.

[0493] exist Fig.11c and Fig.11d The setting of a TDLS direct link based on an off-link is illustrated in the same manner.

[0494] The TDLS initiator STAA1 121 performs TDLS setup with the peer STAB1 131 via AP1 111. Each TDLS setup frame includes a link identifier 400. The TDLS initiator STA address field 402 carried in the link identifier is set to the MLD MAC address of the non-AP MLD 120, the TDLS responder STA address field 403 is set to the MLD MAC address of the non-AP MLD 130, and the BSSID field 401 is set to the MAC address of STAA2 122, which is a STA affiliated to the TDLS initiator non-AP MLD A operating on the target off-link. According to an embodiment, the MAC address of STAA2 122 used as the BSSID is collected by the peer non-AP MLD B through a TDLS link setup request frame or an acknowledgement frame.

[0495] As described above, variations may consider signaling the target off-link in a per-STA profile carried in the TDLS multilink element 450 , or via a link ID bitmap 491 provided in the multilink information element 490 .

[0496] As a result, at step 1250, if the TDLS direct link is established successfully, STA A2 122 and STA B2 132 (TDLS peer STAs) respectively attached to the TDLS peer non-APMLDs 120 and 130 can communicate directly (P2P) over the set up direct link. Fig.11c and Fig.11d As shown, P2P data traffic 226 is exchanged directly between two TDLS peer STAs. Advantageously, each TDLS peer non-AP MLD A and B can continue to operate with AP 111 on other setup links (here, link 151 via STA A1 121 for non-AP MLD A 120 and link 161 via STA B1 131 for non-AP MLD B 130).

[0497] refer to Figures 12a to 12d A second embodiment is described. In these embodiments, a first TDLS direct link is established between the two non-AP MLDs on a first link set up with an AP device. Then, the first TDLS session is switched to an off-link. Thus, the switch establishes a TDLS session on the off-link.

[0498] The first link that originally supported the first TDLS session may then be removed or disabled to remove any activity with the affiliated STAs (now involved in the off-link) of the AP device.

[0499] Fig.12aThe embodiments of the present invention can be implemented by illustrating Figure 1 The example of the figure illustrates two non-AP MLDs (non-AP MLD A 120 and non-AP MLD B 130) with two affiliated STAs (from 121 to 122 and from 131 to 132, respectively) and an AP MLD 110 with two affiliated APs 111 and 112. The two non-AP MLDs associated with the AP MLD 110 initially set up a TDLS direct link session 172a on the same operating frequency band as the AP 2 112 (i.e., on link #2).

[0500] The non-AP MLDs 120 and 130 instantiate or create TDLS links on a set of off-channels (one or more) to obtain off-links 172b for operations outside of AP management. The non-AP MLDs then move the TDLS sessions from link 172a operating on the same channel / band as AP2 112 to off-links 172b that are not located on any operating channel / band of the AP(s) attached to the AP MLD 110. The AP MLDs 120 and 130's own connections to AP2 112 via links 152 and 162, respectively, may then be removed.

[0501] As a result, non-AP MLDs 120 and 130 are able to use the off-link 172b with one of their affiliated stations (STA A2 122 and STA B2 132, respectively) while maintaining the previous connection with the AP MLD through link #1 corresponding to the connection with affiliated AP1.

[0502] Of course, for purposes of illustration, the number of links shown in this figure is not limiting.

[0503] Figure 12b The flowchart illustrates exemplary steps for direct communication according to certain aspects of the present invention. These steps are performed by a (peer) non-AP MLD initiating a TDLS link (off-link) on a set of (one or more) off-channels. As described below, the process involves Fig.11b Similar steps.

[0504] Operations start at step 1510 where the TDLS initiator non-AP MLD obtains a recommended channel for a non-infrastructure BSS or off-channel TDLS direct link from an AP device. Step 1510 is similar to step 1210 described above.

[0505] Fig.12c and Fig.12dThe frame exchanges in the timeline illustrate two different scenarios for creating and using off-links according to embodiments of the present invention. In both scenarios, once a non-AP MLD (its subordinate STA) associates with an AP MLD, channel usage information is obtained from a channel usage response frame 816 exchanged with the AP MLD. Of course, the channel usage information may be obtained from a probe response frame instead.

[0506] Optionally, in step 1520, the TDLS initiator non-AP MD performs a TDLS discovery process to obtain information of (one or more than one) channels and (one or more than one) frequency bands supported by its peer non-AP MLD and their capabilities. Step 1520 is similar to step 1220 already described.

[0507] exist Fig.12d It is schematically shown in Fig.12c Each TDLS discovery frame 221, 222 includes a link identifier 400, in which a TDLS initiator STA address field 402 is set to the MLD MAC address of the non-AP MLD 120, a TDLS responder STA address field 403 is set to the MLD MAC address of the non-AP MLD 130, and a BSSID field 401 is set to the BSSID corresponding to the AP2 112 operating on the basic channel.

[0508] Next, at step 1530, the TDLS initiator non-AP MLD uses the same Fig.12a The TDLS direct link establishment frame is initiated by using the link shared and set by the non-AP MLD (AP2 112 in the example) as the target link, and initiating a conventional TDLS setup (i.e., TDLS direct link establishment) with the peer non-AP MLD. As a reminder, each TDLS setup frame includes a link identifier 400 in which a BSSID field 401 is set to the BSSID of the AP (AP2 112 in the same example) operating on the link on which the non-AP MLD intends to establish a single link TDLS direct link.

[0509] During the TDLS setup phase, the two non-AP MLDs can share their own capabilities, supported channels, supported frequency bands. This is why the TDLS discovery process can be omitted. In other words, the two peer non-AP MLDs can know each other (supported channels and frequency bands) through the TDLS discovery process or through the TDLS setup process.

[0510] Once the TDLS setup process is successfully completed, STA A2 122 and STA B2 132 (TDLS peer STAs) attached to non-AP MLDs 120 and 130, respectively, can communicate via the setup TDLS direct link (P2P data (in Fig.12c and Fig.12d ), but is directly concurrent with the AP's traffic.

[0511] At this stage, the TDLS initiator non-AP MLD can select one or more channels as off-channels based on the recommended channels collected from the AP MLD (via the probe response frame 213 or the channel use response frame 816), and optionally based on the supported channels / bands collected from the peer non-AP MLD (during the TDLS discovery process or the TDLS setup process) and its own supported channels / bands. According to the second embodiment, this or these off-channels define the target off-link to be created for direct or P2P communication.

[0512] The TDLS initiator non-AP MLD then decides to move or switch the set-up TDLS session (direct link) from the TDLS link shared with the AP's traffic to the target off-link.

[0513] In such Fig.12d In some of the embodiments shown, the movement is performed in two steps, and for example Fig.12c Other embodiments shown require a single step. The handoff in the two-step approach is based on a target link (corresponding to an off-link that has not yet been created), while the handoff in the one-step approach is based on a target channel (defined in the same operation as an off-link that has not yet been created).

[0514] At step 1540, which is specific to the two-step method, the TDLS initiator non-AP MLD creates a TDLS link, i.e., an off-link, targeting the selected set of (one or more) off-channels by exchanging TDLS action frames with the peer non-AP MLD, which are tunneled by the AP MLD through the existing TDLS session. Thus, off-links for TDLS communication are created simultaneously at the two peer non-AP MLDs. This step is very similar to step 1230 described above.

[0515] For example, the TDLS initiator non-AP MLD initiates the creation of a TDLS off-link by sending a TDLS link setup request frame to a peer non-AP STA, the TDLS link setup request frame including a link identifier and an operating band of the new link (i.e., one or more off-links selected). The frame may be a TDLS action frame, which includes a target channel element, an operation class element, and a link ID (i.e., a numerical value) identifying an off-link to be created in the future. In a variation, the TDLS link setup request frame may include a multi-link element with multiple per-STA profiles, each per-STA profile conveying a target channel, an operation class, and a link identifier for a corresponding off-link to be created.

[0516] In response, the TDLS initiator non-AP MLD receives a TDLS link setup response frame intended to confirm or not confirm the creation of the off-link(s) using a dedicated code. The response frame may include a counter-proposal to conduct off-link negotiation as described above with reference to step 1230.

[0517] If approved, the TDLS initiator non-AP MLD sends a TDLS link setup confirmation frame to confirm the creation of the off-link. The AP MLD may be notified of the created link ID and the created off-link.

[0518] Fig.12d The exchange of a TDLS link setup request frame 1301 , a TDLS link setup response frame 1302 , and a TDLS link setup confirmation frame 1303 is illustrated.

[0519] The next step is step 1550 where the two peer non-AP MLDs actually switch the TDLS session (set up at step 1530) to the off-link.

[0520] exist Fig.12d In the two-step scenario of TDLS, the handover consists in performing a TDLS link switch, ie, changing the link of an existing TDLS session (instead of just changing the channel or frequency band as in a conventional TDLS channel switch).

[0521] The link switch may be accomplished by exchanging TDLS action frames directly (ie, not tunneled by the AP MLD) with the peer non-AP MLD over the existing TDLS session (on the channel of AP2 112).

[0522] A new type of TDLS action frame can be used in the same scheme as the TDLS switching frame, hereinafter referred to as a TDLS link switching request frame and a corresponding TDLS link switching response frame. Of course, the TDLS switching frame can be upgraded to convey the signal notification required by the TDLS link setting frame described now (rather than creating a new frame).

[0523] The TDLS link switch request frame may be assigned a value of 14 in the action field 302 , and the TDLS link switch response frame may be assigned a value of 15 in the action field 302 .

[0524] For example, one of the two non-AP MLDs sends a TDLS link switch request frame 1620 to the other through any STA A2 122 or STA B2 132 .

[0525] Frame 1620 includes the link ID of the target off-link to which the TDLS handover initiator non-AP MLD intends to move. This is the link ID specified when the off-link is created and set (at step 1540).

[0526] Next, the peer non-AP MLD responds with a TDLS link switch response frame 1621 repeating the link ID and including a status code.

[0527] To confirm the link switch, the response includes a success status code (eg, SUCCESS). As a result, the two peer STAs involved in the initial TDLS session (set up at step 1540) configure themselves to operate on the target off-link.

[0528] In the case of rejection of the link switch, the response includes a rejection status code (eg, REQUEST_DECLINED). As a result, the two STAs continue to operate on the same link (the TDLS session is not moved).

[0529] In order to ensure synchronization between the two peer STAs when they configure themselves to the target off-link, the TDLS link switch request frame 1620 and the response frame 1621 may include a timing information element (9.4.2.63 Channel switch timing element in REVme2.0) to synchronize the moment when the link switch effectively occurs.

[0530] exist Fig.12c In the one-step scenario, the switching consists in performing a TDLS channel switching targeting one or more off-link channels of the off-link to move the first TDLS session to the off-link. TDLS channel switching is a conventional operation defined in section 11.20.6 of REVme2.0, which involves exchanging a TDLS switching request frame and a corresponding response frame.

[0531] For example, one AP MLD among two non-AP MLDs sends a TDLS channel switch request frame 1610 to the other AP MLD through STAA2 122 or B2 132 to move the P2P communication / session to an off-link.

[0532] The TDLS channel switch request frame 1610 includes the target operating frequency band and channel for which the off-link must be established, and a link identifier for identifying a new off-link to be created in the same manner as the above-mentioned TDLS link setup request frame 1301. In addition, the frame 1610 as a switching frame includes timing information for channel switching (9.4.2.63 Channel Switch Timing Element in REVme 2.0).

[0533] The target channel corresponds to an operating channel of an off-link (ie, off-channel) serving as the target channel.

[0534] In the case where an off-link is defined with multiple off-channels, the TDLS channel switch request frame 1610 may also include a multilink element having one or more per-STA profiles defining multiple off-channels. In this case, the operating channel of the off-link used as the target channel may be any channel in the channel entry (channel usage element) corresponding to the off-link. This ensures that the peer STA clearly identifies which off-link is the target of the switch.

[0535] The peer partner STA (B2 in the example) responds with a TDLS channel switch response frame 1611 conveying the same link identifier and status code.

[0536] To confirm the channel switch, the response includes a success status code (eg, SUCCESS). As a result, the two peer STAs involved in the initial TDLS session (set up at step 1540) configure themselves to operate on the target off-link.

[0537] In case of rejection of channel switching, the response includes a rejection status code (eg, REQUEST_DECLINED). As a result, the two STAs continue to operate on the same link (the TDLS session is not moved).

[0538] As can be seen above, the TDLS link switch frame and the TDLS channel switch frame are distinguished from each other mainly by signaling the link ID field (for the former) rather than the target operating band and channel (for the latter).

[0539] As a result (in both the one-step method and the two-step method), after a sufficient period of clear channel assessment (CCA) on the off-link (as described in 11.20.6 TDLS channel switching in REVme 2.0), STAA2 122 and B2 132 (TDLS peer STAs) attached to non-AP MLDs 120 and 130, respectively, can communicate on the off-link at step 1570.

[0540] In other words, the two non-AP MLDs operate point-to-point communication between the first TDLS STA and the second TDLS STA over the created off-link.

[0541] In order to remove any dependency of the peer STA on the AP MLD and thus remove the need to switch back to its primary channel, optional step 1560 (before or during step 1570) removes or disables the link set up by the peer STA involved with the AP MLD (i.e., the set up link that formed the basis for the off-link). Fig.12a In the scenario of , this means that both links 152 and 162 with AP2 112 are removed or disabled.

[0542] In a variant, the removal / disabling operation may be performed before the switching.

[0543] Various implementations of this operation can be envisioned. For example, the removal or disabling of the link set up between any one of the two peer STAs and the AP MLD may include one of the following:

[0544] updating the TID-to-link mappings for the links set up by the corresponding non-AP MLDs and AP MLDs to remove all TIDs assigned to the links to be removed / disabled, and

[0545] A new multilink setup (hence a re-setup) with AP MLD is made excluding the link to be removed / disabled.

[0546] This operation is Fig.12c and Fig.12d 8 is illustrated by arrow 850. Since two peer STAs are involved in the P2P communication on the off-link, another subordinate STA is used to perform the operation at the two peer non-AP MLDs.

[0547] In the example shown, frames intended to remove / disable link 152 are sent by STAA1 121 to AP1 111 , while frames intended to remove / disable link 162 are also sent by STAB1 131 to AP1 111 .

[0548] Fig.10a The communication device 1000 is schematically illustrated as a non-AP MLD embedded in a plurality of non-AP stations 120, 130 or an AP MLD embedded in a plurality of APs 110 configured to implement a radio network (NETW) of at least one embodiment of the present invention. The communication device 1000 may preferably be a device such as a microcomputer, a workstation, or a light portable device. The communication device 1000 includes a communication bus 1113, which is preferably connected to:

[0549] A central processing unit 1001 denoted as CPU, such as a processor;

[0550] Memory 1003, used to store executable codes of methods or method steps according to embodiments of the present invention, and registers suitable for recording variables and parameters required to implement these methods; and

[0551] At least one communication interface 1002 , which is connected via a transmitting and receiving antenna 1004 to a wireless communication network (eg a communication network according to one of the IEEE 802.11 family of standards).

[0552] Preferably, a communication bus provides communication and interoperability between the various elements included in or connected to the communication device 1000. The representation of a bus is not limiting, and in particular, the central processing unit is operable to communicate instructions to any element of the communication device 1000, either directly or through other elements of the communication device 1000.

[0553] The executable code may be stored in a memory (which may be a read-only hard disk) or on a removable digital medium (such as a disk). According to an optional variation, the executable code of the program may be received via the interface 1002 via a communication network to store the executable code in the memory of the communication device 1000 before execution.

[0554] In an embodiment, the apparatus is a programmable device that implements embodiments of the invention using software.Alternatively, however, embodiments of the invention may be implemented in whole or in part in hardware (eg in the form of an application specific integrated circuit or ASIC).

[0555] Fig.10b 1 is a block diagram schematically illustrating the architecture of a communication device 1000 suitable for at least partially performing the present invention. As shown in the figure, the device 1000 includes a physical (PHY) layer block 1023, a MAC layer block 1022 and an application layer block 1021.

[0556] The PHY layer block 1023 (here are multiple 802.11 standardized PHY layer modules) has the task of formatting any 20 MHz channel or composite channel, modulating on any 20 MHz channel or composite channel or demodulating from any 20 MHz channel or composite channel, and thus sending or receiving frames on the radio medium (NETW), such as 802.11 frames, for example, medium access trigger frames for reserving transmission time slots, MAC data frames and management frames based on 20 MHz width for interaction with traditional 802.11 stations, and MAC data frames of OFDMA type with a width less than 20 MHz traditional (usually 2 or 5 MHz) to / from the radio medium.

[0557] The MAC layer block or controller 1022 preferably includes an MLE MAC 802.11 layer 1824 that implements conventional 802.11 MAC operations and an additional block 1025 for at least partially performing embodiments of the present invention. The MAC layer block 1022 may optionally be implemented in software that is loaded into the RAM 1003 and executed by the CPU 1801. The MLE MAC 802.11 layer 1024 may implement an upper MAC stack as well as a series of lower MAC modules.

[0558] Preferably, an additional block 1025 called a P2P management module for off-link operation for TDLS services over multi-link communications implements (at a peer non-AP MLD) a portion of an embodiment of the present invention. Depending on the embodiment implemented, this block makes reference to Figure 5b , Figures 6a to 6c , Figures 7a to 7d , Figure 8 to Figure 8c and Figure 9a to Figure 9b or Figures 11a to 11d and Figures 12a to 12d Describes the operation.

[0559] According to an embodiment of the present invention, the MAC 802.11 layer 1024 and the P2P management 1025 interact with each other to accurately establish and process communications on OFDMA RUs between multiple non-APMLD stations.

[0560] exist Fig.10b In the upper part, the application layer block 1021 runs an application for generating and receiving data packets (for example, data packets such as video streams, etc.). The application layer block 1021 represents all stack layers above the MAC layer according to ISO standardization.

[0561] In an embodiment, the apparatus is a programmable device that implements embodiments of the invention using software.Alternatively, however, embodiments of the invention may be implemented in whole or in part in hardware (eg in the form of an application specific integrated circuit or ASIC).

[0562] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications within the scope of the present invention will be apparent to those skilled in the art.

[0563] When referring to the foregoing illustrative embodiments, those skilled in the art will appreciate many further modifications and variations, which are given by way of example only and are not intended to limit the scope of the invention, which is determined solely by the appended claims. In particular, different features from different embodiments may be interchangeable where appropriate.

[0564] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.

Claims

1. A communication method in a wireless network, comprising: At a non-access point multi-link device (non-AP MLD) associated with an access point device (AP device): obtaining a link identifier, i.e., a link ID, the link ID defining an off-link corresponding to at least one off-channel that does not overlap with one or more channels used by the AP device; Using the link ID as an indication of the off-link for setting up a direct link (TDLS direct link) for a tunneled direct link, to establish the TDLS direct link between a first TDLS STA (first TDLS STA) attached to the non-AP MLD and a second TDLS STA through one or more channels used by the AP device; as well as Point-to-point communication between the first TDLS STA and the second TDLS STA is operated on the off-link.

2. The method according to claim 1, further comprising: Communications with the AP device are operated over another link corresponding to at least one of the one or more channels used by the AP device.

3. The method according to claim 1, wherein: Obtaining the link ID includes receiving information about a virtual AP attached to the AP MLD from the AP device as the AP MLD, the virtual AP defining the off-link and being assigned the link ID, the virtual AP not communicating in its basic service set (BSS).

4. The method according to claim 1, wherein: Establishing the TDLS direct link by the non-AP MLD includes defining the off-link and the link ID based on information about the at least one off-channel received from the AP device.

5. The method according to claim 1, wherein: Establishing the TDLS direct link includes defining the off-link as the TDLS direct link using the link ID to set up the TDLS direct link.

6. The method according to claim 1, wherein: Establishing the TDLS direct link includes: Setting an initial TDLS direct link that enables point-to-point communication between the first TDLS STA and the second TDLS STA; and Channel switching is performed to move the point-to-point communication from the initial TDLS direct link to the target link using the channel of the off-link as a target channel for a target link or defining the off-link as the target link using the link ID.

7. The method according to claim 6, further comprising: At the non-AP MLD, the initial TDLS direct link is disabled or removed.

8. The method according to claim 1, wherein: Obtaining the link ID includes creating, by the non-AP MLD, a TDLS link with a self-link ID defining an off-link corresponding to at least one off-channel that does not overlap with one or more channels used by the AP device.

9. The method according to claim 8, wherein: Creating the TDLS link includes triggering creation of the same TDLS link at another non-AP MLD.

10. The method according to claim 8, wherein: Establishing the TDLS direct link includes: establishing a TDLS direct link with the second TDLS STA with the created off-link as a target.

11. The method according to claim 11, wherein: The TDLS setup frames exchanged during the TDLS direct link establishment include a MAC address for identifying the first TDLS STA of the created off-link.

12. The method according to claim 8, wherein: Creating the TDLS link includes exchanging TDLS action frames tunneled by the AP device with another non-AP MLD to simultaneously create the off-link at the two non-AP MLDs.

13. The method according to claim 12, wherein: The exchange of TDLS action frames includes: for the non-AP MLD, sending a link setup request to create an off-link corresponding to at least one candidate off-channel that does not overlap with one or more channels used by the AP device; and In response to sending the link setup request, a link setup response is received, the link setup response including an alternate off-link corresponding to at least one alternate off-channel that does not overlap with one or more channels used by the AP device.

14. The method according to claim 8, further comprising: A first TDLS direct link between the two non-AP MLDs is established on a first link set with the AP device for a first TDLS session, and the first TDLS session is switched to the off-link.

15. The method according to claim 14, wherein: Switching the first TDLS session to the off-link includes performing a TDLS link switch to move the first TDLS session to the off-link.

16. The method according to claim 15, wherein: Performing the TDLS link switching includes: directly exchanging TDLS action frames on the first TDLS direct link.

17. The method according to claim 14, wherein: Switching the first TDLS session to the off-link includes performing a TDLS channel switch targeting one or more off-channels of the off-link to move the first TDLS session to the off-link.

18. The method according to claim 14, further comprising: The first link set with the AP device is removed or disabled.

19. The method according to claim 18, wherein: Removing or disabling the first link includes one of the following: updating a TID-to-link mapping of a link set up with the AP device to remove all TIDs assigned to the first link; as well as A multi-link setting with the AP device excluding the first link is performed.

20. The method according to claim 1, wherein: The link ID defining the off-link is selected from a set of candidate link IDs that are deprived of any link ID used by the AP device.

21. The method according to claim 8, further comprising: In response to creating the off-link, the AP device is notified of the created off-link.

22. The method according to claim 1, wherein: A basic service set identifier (BSSID) is allocated to the off-link, and the BSSID is set to a MAC address of one of the TDLS STAs or one of the two non-AP MLDs.

23. The method according to claim 1, wherein: Obtaining the link identifier includes obtaining recommended channels of a non-infrastructure BSS or an off-channel TDLS direct link from the AP device, and selecting one or more off-channels from the recommended channels.

24. The method according to claim 12 or 16, wherein: The TDLS action frame includes a multi-link element having one or more per-STA profiles for respectively signaling one or more off-channels for the off-link.

25. A communication method in a wireless network, comprising: At a non-APMLD associated with an access point multi-link device, AP MLD, receiving from the AP MLD information about a virtual AP attached to the AP MLD, the virtual AP not communicating in its basic service set (BSS), the virtual AP defining an off-link corresponding to at least one off-channel that does not overlap with one or more channels used by the AP MLD, the attached virtual AP being assigned a link identifier (link ID) to identify the off-link; and Communicating over the wireless network using the link ID.

26. The method according to claim 25, wherein: Communicating over the wireless network using the link ID includes: Using the link ID as the off-link indication for a tunneled direct link to set up a direct link, i.e., a TDLS direct link, to establish the TDLS direct link between a first TDLS STA attached to the non-AP MLD and a second TDLS STA through one or more channels used by the AP device; and Point-to-point communication between the first TDLS STA and the second TDLS STA is operated on the off-link.

27. The method according to claim 1 or 26, wherein: Establishing the TDLS direct link includes at least one of the following operations: Including a link identifier (400) corresponding to the virtual AP and thus corresponding to the off-link in a TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA, wherein the link identifier (400) includes a BSSID field having a basic service set identifier (BSSID); Adding the off-link in a per-STA profile sub-element (530) carried in a TDLS multilink element (500) exchanged between the first TDLS STA and the second TDLS STA; as well as A multilink link information element (490) is included in the TDLS setup frame exchanged between the first TDLS STA and the second TDLS STA, and the multilink link information element (490) includes a link ID bitmap (491) indicating the off-link.

28. A communication method in a wireless network, comprising: At the access point multi-link device, AP MLD, Instantiating an auxiliary virtual AP, the auxiliary virtual AP defining an off-link corresponding to at least one off-channel that does not overlap with one or more channels used by the AP MLD, the auxiliary virtual AP being assigned a link identifier, i.e., a link ID, to identify the off-link, the virtual AP not communicating in its basic service set, i.e., a BSS; as well as Information about the affiliated virtual AP defining the off-link is transmitted to a non-AP MLD, the information including the link ID.

29. The method according to claim 28, further comprising: receiving a trigger for the instantiation of the subordinate virtual AP, wherein the trigger belongs to the group consisting of: receiving a probe request frame (212, 812) from the non-AP MLD when the non-AP MLD is not yet associated with the AP MLD, the probe request frame (212, 812) including an off-link capability and / or a channel usage element (600) as a new input in extended capabilities; receiving a channel usage request frame (815) from the non-AP MLD in a case where the non-AP MLD is associated with the AP MLD, the channel usage request frame including a channel usage element requesting setup of the off-link; receiving quality of service characteristics, ie, QoS characteristics; and Detect triggering inside the AP MLD.

30. The method of claim 3, 25 or 28, wherein: In addition to the link ID, the information about the virtual AP also includes one or more parameters, the one or more parameters belonging to the group consisting of: Operation class; Channel number; The channel width used to define the operating frequency band; BSSID; Information related to the BSSID indicating that the virtual AP is unreachable; as well as Non-inherited elements.

31. The method according to claim 30, wherein: The virtual AP can be distinguished from APs capable of communication using a specific value of the AP reachability field from the BSSID information element.

32. The method of claim 3, 25 or 28, wherein: Said information about said subordinate virtual AP is at least partially exchanged as part of a multilink element (500) in a probe response frame (213) or in a beacon frame (211) or in an association response frame (215), and wherein: The subordinate virtual AP is declared as an additional STA in the multilink element (500), the multilink element (500) having a dedicated per-STA profile sub-element (530), the per-STA profile sub-element (530) containing information (560, 561) to distinguish the subordinate virtual AP from other subordinate APs of the AP MLD; or The common information field (520) of the multi-link element (500) includes an off-link bitmap or a virtual AP bitmap subfield.

33. The method of claim 32, wherein: The per-STA profile sub-element (530) specific to the subordinate virtual AP: including non-inherited elements carrying at least one of AP capabilities and operations that are not useful in the context of a virtual AP due to the fact that the virtual AP does not communicate in its basic service set, i.e., BSS; or Not subject to inheritance.

34. The method of claim 3, 25 or 28, wherein: The information about the affiliated virtual AP is at least partially exchanged as part of a neighbor report element or a simplified neighbor report element (910) included in a beacon frame (211), the part being an off-link field (944) or a usage mode field (945) included in an MLD parameter subfield (940), and giving information related to a link corresponding to the content of a link ID field (942) also included in the MLD parameter subfield (940).

35. The method of claim 3, 25 or 28, wherein: The information about the subordinate virtual AP includes information about the at least one off-channel of the AP MLD exchanged as a channel usage element (600), The channel usage element (600) comprises: a link ID information field (650) containing the link ID and associated with all channel entries of the channel entry field (640); or a link ID information subfield (643) of the channel entry field (640), the link ID information subfield (643) containing the link ID and associated with all channel entries of the channel entry field (640); and The channel usage element (600) is included in a probe response frame (213) or a channel usage response frame (816).

36. A wireless communication device comprising at least one microprocessor configured to perform the method of claim 1, 25 or 28.

37. A tunneled direct link setup action frame (TDLS action frame) to be exchanged between two non-access point multi-link devices (non-AP MLDs) associated with an access point device (AP device), the frame comprising: an Action field set to a value strictly greater than 10 to indicate that the frame is a request to create a TDLS link with an Own Link ID that defines an off-link corresponding to at least one off-channel that does not overlap with one or more channels used by the AP device; as well as At least one information element, ie at least one IE, defines the link ID and includes the at least one off-channel.

38. A tunneled direct link setup action frame (TDLS action frame) to be exchanged between two non-access point multi-link devices (non-AP MLDs) associated with an access point (AP) device, the frame comprising: an Action field, which is set to a value strictly greater than 10 to indicate that the frame is a request to move a current TDLS session on a first link having a first link ID to a second link having a different second link ID; as well as At least one information element field, namely at least one IE field, indicates the second link ID.

39. The TDLS action frame according to claim 38, wherein: The second link ID identifies an off-link defined on at least one off-channel that does not overlap with one or more channels used by the AP device.

40. The TDLS action frame according to claim 38, wherein: The at least one IE includes a BSSID field associated with the second link, the BSSID field being set to a MAC address of one of the non-AP MLDs or a MAC address of a station affiliated with one of the non-AP MLDs.

41. A non-transitory computer readable medium storing a program which, when executed by a microprocessor or a computer system in a wireless device, causes the wireless device to perform the method according to claim 1, 25 or 28.

Images