Communication method and device to signal enhanced multi-link operating mode

Abstract

To provide a communication method in which: in a wireless network implementing multilink transmission, an AP MLD spontaneously sends an EML OM Notification frame involving an optional set of EML Links, to activate or deactivate or modify an EML OM.SOLUTION: The method is such that: a destination non-AP MLD initiates an EML OM activation or deactivation as suggested, and upon receiving a request for EML OM activation or deactivation, the AP MLD refuses the request and responds with another proposed set of links. Signalling in a request frame is simplified by using a single one-bit field to implicitly activate or deactivate the single EML OM, of either one of EMLSR or EMLMR mode, declared as being supported during the association of the non-AP MLD.SELECTED DRAWING: Figure 6B

Description

[Technical Field]

[0001] The present invention relates generally to wireless communications, and more particularly to multi-link (ML) communications. [Background technology]

[0002] Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcasting, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing 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 frequency division multiple access (OFDMA) networks, and single-carrier frequency division multiple access (SC-FDMA) networks.

[0003] The 802.11 family of standards, adopted by the Institute of Electrical and Electronics Engineers (IEEE) provides numerous mechanisms for wireless communication between stations.

[0004] With the development of latency-sensitive applications such as online gaming, real-time video streaming, virtual reality, and remote control of drones and robots, requirements and issues of better throughput, low latency, and robustness must be considered. These issues are currently being considered by the IEEE 802.11 Working Group as the primary objective of issuing the next major 802.11 release, known as 802.11be (Extremely High Throughput) or EHT (Extremely High Throughput).

[0005] The IEEE P802.11be / D1.1 version (July 2021, hereinafter referred to as the "D1.1 standard") introduces multi-link (ML) operation (MLO), which improves data throughput by enabling communication between stations over multiple simultaneous and discontinuous communication links.

[0006] MLO allows a non-AP (Access Point) MLD (ML Device) to register with an AP MLD, i.e., discover, authenticate, connect, and configure multiple links with the AP MLD. Each link allows channel access and frame exchange between the non-AP MLD and the AP MLD based on the supported capabilities exchanged during the association procedure.

[0007] An MLD is a logical entity with affiliated stations (STAs) and a single medium access control (MAC) service access point (SAP) for a logical link control (LLC), containing one MAC data service. Thus, an AP MLD consists of multiple affiliated APs, and a non-AP MLD consists of multiple affiliated non-AP stations. Affiliated stations in both AP MLDs and non-AP MLDs may communicate with affiliated stations in another MLD via each of the established communication links using 802.11 mechanisms.

[0008] With the introduction of spatial multiplexing functions of MLO and MLD, the D1.1 standard introduced new operating modes (OMs) called Enhanced Multi-Link Operating Modes (EML OMs), namely, EMLSR (Enhanced Multi-Link Single Radio) mode and EMLMR (Enhanced Multi-Link Multi-Radio) mode.

[0009] In EMLSR mode, the non-AP MLD can simultaneously listen on a set of valid links (called EMLSR links) for receiving initial control frames (MU-RTS, BSRP, etc.) from the AP MLD, and can exchange data frames with the AP MLD over only one link at a time (usually the link over which the initial control frame was received).

[0010] In EMLMR mode, non-AP MLD aggregates the physical resources of multiple radios dedicated to multiple active links (called EMLMR links) to transmit and receive data up to a predefined number of supported receive / transmit spatial streams. This predefined number is greater than the number of supported receive / transmit spatial streams per radio, providing improved throughput and reduced latency. As an example, a multi-radio (MR) non-AP MLD supporting EMLMR mode with two links (and associated radios) communicates over both links using two radios when EMLMR mode is deactivated, for example, in a 2x2 MIMO antenna configuration. On the other hand, when EMLMR mode is activated, for example, in a 4x4 MIMO antenna configuration, it communicates over one of the two links using one of the radios with the aggregated physical resources of the two radios (usually antennas). During this time, the other link (the link with the deprived physical antenna) is unavailable.

[0011] During the association phase, a non-AP MLD declares its support for each EML operation mode (called EML Capabilities) to an AP MLD.

[0012] In operational mode, the enabling (called "Initiation") and disabling (called "Termination") of EML operational modes is initiated by the non-AP MLD transmitting a specific EHT action frame called "EML OM Notification". The EML OM Notification frame contains one bit each for EMLSR and EMLMR modes, signaling which mode is associated with the activation or deactivation.

[0013] Current activation / deactivation schemes are not entirely satisfactory.

[0014] For example, the proposed signaling incurs overhead and could be improved.

[0015] Also, this scheme is primarily driven by the constraints of non-AP MLD itself, without considering the overall network state. Summary of the Invention

[0016] A broad object of the present invention is to overcome some of the above-mentioned concerns.

[0017] In this context, an embodiment of the present invention provides an access point (AP) multi-link device (MLD) that: A method of communication in a wireless network is provided that includes transmitting a first Enhanced Multi-Link Operating Mode (EML OM) Notification frame to a non-AP MLD that defines a proposal from the AP MLD to activate, deactivate, or change the EML OM.

[0018] Correspondingly, a communication method in a wireless network includes, in a non-access point (non-AP) multi-link device (MLD), and receiving a first Enhanced Multi-Link Operating Mode (EML OM) Notification frame from the AP MLD that defines a proposal from the AP MLD to activate, deactivate, or change the EML OM.

[0019] Such proposals will be submitted to the non-AP MLD for approval and, if approved as described below, the non-AP MLD may request the proposed activation / deactivation / modification.

[0020] Unlike the conventional activation / deactivation method in which a non-AP MLD initiates the exchange of notification frames, the AP MLD can now spontaneously send the first EML OM Notification frame. "Spontaneous" means that the AP MLD does so on its own initiative, without prompting from a non-AP MLD. For example, the proposal transmission is not in response to a frame (e.g., an EML OM Notification frame) received from a non-AP MLD. Such spontaneous transmission by the AP MLD means that the AP MLD takes the initiative to propose activation, deactivation, or modification of the EML OM.

[0021] This approach allows the AP MLD's holistic view of the network to be taken into account in the process of deciding to activate, deactivate, or even change the EML OM.

[0022] Although optional features of these embodiments of the invention are defined below with reference to methods, they can be substituted with device features.

[0023] In some embodiments, the method further includes receiving, at the AP MLD, a request EML OM Notification frame from the non-AP MLD in response to the transmission, requesting activation or deactivation of the EML OM. This confirms that the non-AP MLD, which traditionally drove the activation / deactivation scheme, has considered the proposal from the AP MLD. Correspondingly, the method further includes transmitting a request EML OM Notification frame to the AP MLD in response to the received frame, requesting activation or deactivation of the EML OM.

[0024] In yet another embodiment, the first EML OM Notification frame includes a field (e.g., an EML Link Bitmap field) signaling a set of proposed links for activating or modifying the EML OM between the two MLDs. Thus, the AP MLD proposes a set of candidate EMLSR or EMLMR links to use for the resulting EML OM (activated or modified). In fact, the requested MLD may want to use a specific EML link for the EML OM.

[0025] In some embodiments, the Request EML OM Notification frame includes the same set of proposed links for the requested EML OM, thereby ensuring that the non-AP MLD initiates the activation or modification of the EML OM using the EMLSR or EMLMR link desired by the AP.

[0026] In a variant, the Request EML OM Notification frame contains a different link set than the proposed link set for the requested EML OM, which opens the possibility for non-AP MLD to change the proposed link to a more efficient link from its point of view.

[0027] In some embodiments, the EML OM Notification frame includes an EML Mode subfield set to the same activation or deactivation value (e.g., 1 corresponds to mode activation), thereby confirming that the proposal from the AP MLD has been considered by the requesting non-AP MLD.

[0028] In some embodiments, the method further includes exchanging an acknowledgement frame from the AP MLD to the non-AP MLD that acknowledges the request EML OM Notification frame and triggers the actual activation or deactivation of the requested EML OM. The acknowledgement may be simply a MAC ack frame, another EML OM Notification frame, or both.

[0029] In some embodiments, the first EML OM Notification frame proposes a change of a currently active EML OM, and the method further includes receiving, in the AP MLD, in response to transmission of such a frame, a first request EML OM Notification frame requesting deactivation of the currently active EML OM, and receiving from the non-AP MLD a second request EML OM Notification frame requesting activation of the same EML OM with a set of links different from the links of the currently active EML OM. This illustrates a two-step procedure for changing a currently active EML OM with a new set of links. Correspondingly, the method further includes transmitting, in the non-AP MLD, in response to the received frame, a first request EML OM Notification frame to the AP MLD requesting deactivation of the currently active EML OM, and a second request EML OM Notification frame requesting activation of the same EML OM with a set of links different from the links of the currently active EML OM.

[0030] In some embodiments, the set of links that is different from the links of the currently active EML OM is the set of proposed links signaled in the first EML OM Notification frame, in other words, it is the set of links proposed by the AP MLD to modify the current EML OM.

[0031] Some embodiments of the present invention that overcome some of the above concerns include, in a requestee multi-link device (MLD) (e.g., an access point (AP) MLD): In response to receiving a first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame from a requesting MLD (e.g., a non-AP MLD) requesting activation of an EML OM, a response EML OM Notification frame is sent to the requesting MLD, signaling a set of proposed links for activating the EML OM.

[0032] Correspondingly, a communication method in a wireless network includes, in a requesting multi-link device (MLD) (e.g., a non-AP MLD), Sending a first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame to a requested MLD (e.g., AP MLD) requesting activation of EML OM; In response, receiving a response EML OM Notification frame from the requested MLD signaling a proposed set of links for activating said EML OM.

[0033] This approach allows the management of EML OM to take into account other MLDs' knowledge of the state of the network (through link suggestions for activation).

[0034] Although optional features of these embodiments of the invention are defined below with reference to methods, they can be substituted with device features.

[0035] In some embodiments, the method further includes, at the requesting MLD, subsequently receiving from the requesting MLD a second request EML OM Notification frame requesting the activation of the EML OM using the proposed set of links, thereby confirming that the requesting MLD driving the activation / deactivation scheme has considered the proposal from the requested MLD. Correspondingly, the method further includes, at the requesting MLD, in response to receiving the response EML OM Notification frame, sending to the requesting MLD a second request EML OM Notification frame requesting the activation of the EML OM using the proposed set of links.

[0036] In some embodiments, the first request EML OM Notification frame includes a field (e.g., an EML Link Bitmap field) that signals a link that is empty. Signaling such an empty (bitmap) field may mean that the requested MLD wants to activate an EML mode of operation but does not know which link to use. Thus, the present invention advantageously allows the requested MLD to signal which link to use.

[0037] In a variant, the first requesting EML OM Notification frame signals a set of links different from the set of proposed links, meaning that the requested MLD takes advantage of the invention to offer a set of links other than the set of links initially considered by the requested MLD, which in effect contributes to using a set of links more adapted to the requested MLD's knowledge of the network.

[0038] In some embodiments, the response EML OM Notification frame includes an EML Mode subfield set with the same activation value for the requested EML OM as the first request EML OM Notification frame (e.g., 1 corresponds to mode activation). Thus, the {same activation value, new link bitmap} pair allows the requesting MLD to know that a different link set must be used for activation.

[0039] In a variant, the reply EML OM Notification frame includes an EML Mode subfield set to the opposite value (e.g., 0) of the activation value of the same subfield in said first request EML OM Notification frame (e.g., 1 corresponds to mode active). Thus, the {opposite activation value, new link bitmap} pair alerts the requesting MLD that EML mode is either not activated or is activated in the new (proposed) link set.

[0040] In some embodiments, the requesting MLD is configured to start a local Transition Timeout timer upon receiving an acknowledgement response to a sent EML OM Notification frame requesting activation or deactivation of an EML OM, and upon expiry of the timer, the requested activation or deactivation is actually performed, and the method further includes, at the requesting MLD, not starting a local Transition Timeout timer upon receiving an acknowledgement response to the first request EML OM Notification frame if the first request EML OM Notification frame includes a field signaling an empty link (e.g., an EML Link Bitmap field). Similarly, the requested MLD is configured to start a local Transition Timeout timer when sending an acknowledgment response to a received EML OM Notification frame requesting activation or deactivation of an EML OM, and upon expiration of the timer, the requested activation or deactivation is actually performed, and the method further includes, in the requested MLD, not starting a local Transition Timeout timer when sending an acknowledgment response to the first request EML OM Notification frame if the first request EML OM Notification frame includes a field signaling an empty link, thereby preventing the MLD from automatically activating the requested EML OM even when an EML link is not defined.

[0041] Some embodiments of the present invention that overcome some of the above concerns include, in a requestee multi-link device (MLD) (e.g., an access point (AP) MLD): receiving a request Enhanced Multi-Link (EML) Operating Mode (OM) Notification frame from a requesting MLD requesting activation or deactivation of an EML Single-Radio (EMLSR) OM or an EML Multi-Radio (EMLMR) OM; The request EML OM Notification frame indicates a set of links to be used by the EMLSR OM if the request EML OM Notification frame requests activation of the EMLSR OM, and includes a single bitmap subfield indicating a set of links to be used by the EMLMR OM if the request EML OM Notification frame requests activation of the EMLMR OM.

[0042] Correspondingly, a communication method in a wireless network includes, in a requesting multi-link device (MLD), sending a request Enhanced Multi-Link (EML) Operating Mode (OM) Notification frame to the requested MLD requesting activation or deactivation of an EML Single-Radio (EMLSR) OM or an EML Multi-Radio (EMLMR) OM; The Request EML OM Notification frame includes a single bitmap subfield that indicates the set of links to be used in the EMLSR OM if the Request EML OM Notification frame is requesting activation of the EMLSR OM, or indicates the set of links to be used in the EMLMR OM if the Request EML OM Notification frame is requesting activation of the EMLMR OM. Thus, the same subfield is used to indicate which EML links to use whether the EMLSR or EMLMR OM is activated. This simplifies the frame format while saving bits.

[0043] Although optional features of these embodiments of the invention are defined below with reference to methods, they can be substituted with device features.

[0044] In some embodiments, if a Request EML OM Notification frame requests deactivation of both an EML OM and an EMLMR OM, the Request EML OM Notification frame does not have a bitmap subfield indicating the set of links in the EML OM.

[0045] In some embodiments, the Request EML OM Notification frame includes an EMLSR Mode subfield that is set to 1 or 0, respectively, to request activation or deactivation of said EMLSR mode, and an EMLMR Mode subfield that is set to 1 or 0, respectively, to request activation or deactivation of said EMLMR mode.

[0046] In an embodiment, when the EMLSR Mode subfield is set to 1, the single Bitmap subfield indicates the set of links used in the EMLSR OM, when the EMLMR Mode subfield is set to 1, the single Bitmap subfield indicates the set of links used in the EMLMR OM, and when the EMLSR Mode subfield is set to 0 and the EMLMR Mode subfield is set to 0, the Request EML OM Notification frame does not have a Bitmap subfield indicating the set of links in the EML OM.

[0047] Some embodiments of the present invention that overcome some of the above concerns include, in a requestee multi-link device (MLD) (e.g., an access point (AP) MLD): receiving a capability declaration from a requesting MLD (e.g., a non-AP MLD) that the requesting MLD supports Enhanced Multi-Link (EML) operation; subsequently receiving a request EML Operating Mode (OM) Notification frame from the requesting MLD requesting activation or deactivation of the EML OM; When a 1-bit field of the request EML OM Notification frame is set to a first value, activating an EML Single-Radio (EMLSR) OM with the requesting MLD if the non-AP MLD has declared an ability to support EMLSR operation, and activating an EML Multi-Radio (EMLMR) OM with the requesting MLD if the non-AP MLD has declared an ability to support EMLMR operation.

[0048] Correspondingly, a communication method in a wireless network includes, in a requesting multi-link device (MLD) (e.g., a non-AP MLD), Declaring to the requested MLD (e.g., AP MLD) its ability to support Enhanced Multi-Link (EML) operation; sending a request EML Operating Mode (OM) Notification frame to the requestee MLD requesting activation or deactivation of EML OM; If the 1-bit field of the request EML OM Notification frame is set to a first value, activating an EML Single-Radio (EMLSR) OM with the requested MLD if the non-AP MLD has declared an ability to support EMLSR operation, and activating an EML Multi-Radio (EMLMR) OM with the requested MLD if the non-AP MLD has declared an ability to support EMLMR operation.

[0049] Thanks to the capability declaration supporting either EMLSR or EMLMR operation, a one-bit field is sufficient to request activation or deactivation of EML OM and activation or deactivation of the implicit EMLSR or EMLMR mode, based on the declared capability. This extended signaling saves overhead compared to the signaling defined in the D1.1 standard.

[0050] Although optional features of these embodiments of the invention are defined below with reference to methods, they can be substituted with device features.

[0051] In some embodiments, the method further includes deactivating a currently active EML OM when the one-bit field is set to a second value different from the first value.

[0052] In some embodiments, the capability declaration is conveyed in a field having a first subfield declaring support for EMLSR operations and a second subfield declaring support for EMLMR operations, where only one of the two subfields is valid, and thus the two supports are exclusive of one another.

[0053] In another embodiment, the request EML OM Notification frame includes a field (e.g., an EML Link Bitmap field) that signals a set of links for activating EMLSR or EMLMR OM between two MLDs. Thus, a set of EMLSR or EMLMR link candidates is proposed by the requesting MLD.

[0054] Some embodiments of the present invention that overcome some of the above concerns include, in a requestee multi-link device (MLD) (e.g., an access point (AP) MLD): receiving a first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame from a requesting MLD (e.g., a non-AP MLD) requesting activation of an EML OM, the first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame including a field (e.g., an EML Link Bitmap field) signaling a set of links to be used in the EML OM; exchanging data with the requesting MLD using the activated EML OM; A method for communication in a wireless network is provided, comprising receiving, from a requesting MLD, a second request EML OM Notification frame requesting deactivation of the activated EML OM, the second request EML OM Notification frame not having a field signaling a set of links.

[0055] Correspondingly, a communication method in a wireless network includes, in a requesting multi-link device (MLD) (e.g., a non-AP MLD), sending a first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame to a requested MLD (e.g., AP MLD) requesting activation of an EML OM, the first request Enhanced Multi-Link Operating Mode (EML OM) Notification frame including a field signaling a set of links to be used in the EML OM; exchanging data with the requested MLD using the activated EML OM; and transmitting to the requested MLD a second request EML OM Notification frame requesting deactivation of the activated EML OM, the second request EML OM Notification frame not having a field signaling a set of links.

[0056] This communication method provides asymmetry between the two request EML OM Notification frames, because the second frame for deactivation does not contain the EMLSR or EMLMR link bitmaps, as opposed to the first one, which reduces the overhead of the activation / deactivation method compared to the technique of including link bitmaps in the Notification frame.

[0057] Some embodiments of the present invention that overcome some of the above concerns include, in a requestee multi-link device (MLD) (access point (AP) MLD): A method for communication in a wireless network is provided, comprising: in response to receiving a request Enhanced Multi-Link Operating Mode (EML OM) Notification frame from a requesting MLD (non-AP MLD) requesting activation or deactivation of EML OM, transmitting a response EML OM Notification frame to the requesting MLD denying the activation or deactivation.

[0058] Correspondingly, a communication method in a wireless network includes, in a requesting multi-link device (MLD) (non-AP MLD), sending an Enhanced Multi-Link Operating Mode (EML OM) Notification frame to a requested MLD (AP MLD) requesting activation or deactivation of EML OM; In response, receiving a response EML OM Notification frame from the requested MLD denying said activation or deactivation.

[0059] This approach allows the activation / deactivation method to take into account knowledge of the network by MLDs other than the requesting MLD requesting EML OM activation. Indeed, MLDs such as APs in a BSS may have information or constraints that the requesting MLD does not know, such as the amount of data transmitted on the downlink to non-AP MLDs, the current interference within the BSS, or NSTR constraints if the AP MLD is a soft AP. Therefore, the requested MLD may decide to deny a request to enter or exit an EML OM in order to maintain network efficiency.

[0060] Although optional features of these embodiments of the invention are defined below with reference to methods, they can be substituted with device features.

[0061] In some embodiments, the request EML OM Notification frame includes an EML Mode subfield for the requested EML OM set to an activation or deactivation value (e.g., 1 corresponds to activating the mode), and the response EML OM Notification frame includes an EML Mode subfield for the EML OM set to the opposite value (e.g., 0). In this way, the EML OM Notification frame can maintain the format defined in the D1.1 standard.

[0062] In another embodiment, the reply EML OM Notification frame is included in the same Physical Protocol Data Unit (PPDU) as the (MAC) acknowledgement to said request EML OM Notification frame, so that the requesting MLD can know of the rejection before (upon receiving the acknowledgement) starting the Transition Timeout timer, the expiration of which will activate or deactivate the requested EML OM.

[0063] In some embodiments, the requesting MLD is configured to start a local Transition Timeout timer upon receiving an acknowledgement response to a sent EML OM Notification frame requesting activation or deactivation of an EML OM, and upon expiry of said timer, said requested activation or deactivation is actually performed, and the method further comprises not starting a local Transition Timeout timer at the requesting MLD upon receiving an acknowledgement response to a request EML OM Notification frame included in the same Physical Protocol Data Unit (PPDU) as a response EML OM Notification frame rejecting said activation or deactivation. Similarly, the requested MLD is configured to start a local Transition Timeout timer when sending an acknowledgment for a received EML OM Notification frame requesting activation or deactivation of an EML OM, and upon expiration of the timer, the requested activation or deactivation is actually performed, and the method further includes, in the requested MLD, not starting a local Transition Timeout timer when sending an acknowledgment for a request EML OM Notification frame included in the same Physical Protocol Data Unit (PPDU) as a response EML OM Notification frame rejecting the activation or deactivation, thereby preventing the MLD from automatically activating the requested EML OM despite the pending rejection.

[0064] In yet another embodiment, the response EML OM Notification frame includes a field signaling a proposed set of links for activating the EML OM between the two MLDs. Thus, for example, a set of candidate EMLSR or EMLMR links may be proposed by a requestee MLD that rejects the requested EML OM activation. This applies in particular to the rejection of an EML OM activation request due to an inappropriate EML link. In fact, the requestee MLD may wish to use a specific EML link when the EML OM mode is activated.

[0065] According to a particular embodiment, the set of proposed links is different from the first set of links signaled in the request EML OM Notification, which allows the requestee MLD to reject EML OM activation due to the links signaled in its request by the requesting MLD, while proposing new links for activation.

[0066] In that case, the method may further include exchanging a subsequent EML OM Notification frame from the requesting MLD to the requested MLD with the proposed link set requesting activation of EML OM, where the proposed links have been considered by the requesting MLD for initiating EML OM.

[0067] Relatedly, the present invention also provides a wireless communication device including at least one microprocessor configured to perform the steps of any of the above methods, the wireless communication device being either a non-AP MLD or AP MLD.

[0068] Another aspect of the present invention relates to a non-transitory computer readable medium storing a program which, when executed by a microprocessor or computer system in a wireless device, causes the wireless device to perform any of the methods defined above.

[0069] At least part of the methods according to the present invention can be computer-implemented. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which can be referred to generally herein as a "circuit," "module," or "system." Furthermore, the present invention can take the form of a computer program product embodied in any tangible medium having computer-usable program code embodied in the medium.

[0070] Because the present invention can be implemented in software, the present invention can be embodied as computer-readable code for provision to a programmable device on any suitable carrier medium. The tangible carrier medium can comprise a storage medium such as a hard disk drive, a magnetic tape device, or a solid-state memory device. The transitory carrier medium can include signals such as electrical, electronic, optical, acoustic, magnetic, or electromagnetic signals, e.g., microwave or RF signals. [Brief explanation of the drawings]

[0071] Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings: [Figure 1] 1 illustrates a typical 802.11 network environment including ML transmission. [Figure 2] This refers to the Basic variant Multi-Link Element specified in IEEE P802.11be / D1.1. [Figure 3A] This shows the format of the EML Control field that forms the EML OM Notification frame used to activate or deactivate EML OM, as defined in the D1.1 standard. [Figure 3B]Indicates an alternative format for the EML Control field. [Figure 4] 1 illustrates schematically an exemplary sequence of EML OM Management frames for activating or deactivating an EML Operating Mode as defined in the IEEE P802.11be / D1.1 document. [Figure 5A] 10 illustrates an alternative format for an EML Control field according to an embodiment of the present invention. [Figure 5B] 10 illustrates an alternative format for an EML Control field according to an embodiment of the present invention. [Figure 5C] 10 illustrates an alternative format for an EML Control field according to an embodiment of the present invention. [Figure 6A] 10 illustrates a schematic diagram of EML OM Management for rejecting a requested activation or deactivation of an EML Operation Mode according to an embodiment of the present invention. [Figure 6B] 10 illustrates a schematic diagram of EML OM Management for rejecting a requested activation or deactivation of an EML Operation Mode according to an embodiment of the present invention. [Figure 7A] 1 illustrates schematically EML OM Management in which an AP MLD spontaneously proposes activation of an EML OM according to an embodiment of the present invention; [Figure 7B] 1 illustrates a schematic diagram of EML OM Management in which an AP MLD spontaneously proposes activation of an EML OM according to an embodiment of the present invention; [Figure 8] 1 illustrates schematically EML OM Management in which an AP MLD proactively proposes deactivation of a currently active EML OM according to an embodiment of the present invention; [Figure 9] 10 illustrates a schematic diagram of EML OM management in which an AP MLD spontaneously proposes modifications to a currently active EML OM according to an embodiment of the present invention; [Figure 10]10 illustrates schematically EML OM Management in which an AP MLD is requested to indicate a set of links to be used to activate an EML OM according to an embodiment of the present invention; [Figure 11] 1 illustrates a schematic diagram of an EMLMR executable architecture for MLDs for implementing embodiments of the present invention. [Figure 12] 1 is a schematic diagram of a wireless communication device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0072] The techniques described herein can be used in various broadband wireless communication systems, including communication systems based on orthogonal multiplexing. Examples of such communication systems include spatial 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 utilize sufficiently different directions to simultaneously transmit data belonging to multiple user terminals, i.e., wireless devices or stations. TDMA systems divide the transmission signal into different time slots or resource units, and assign each time slot to a different user terminal, allowing multiple user terminals to share the same frequency channel. OFDMA systems utilize orthogonal frequency division multiplexing (OFDM). OFDM is a modulation technique that divides the overall system bandwidth into multiple orthogonal subcarriers or resource units. These subcarriers are sometimes called tones, bins, etc. In OFDM, each subcarrier is independently modulated with data. An SC-FDMA system may utilize Interleaved FDMA (IFDMA), which transmits on subcarriers distributed across the system bandwidth, Localized FDMA (LFDMA), which transmits on blocks of adjacent subcarriers, or Enhanced FDMA (EFDMA), which transmits on multiple blocks of adjacent subcarriers.

[0073] The teachings herein may be incorporated into (e.g., implemented within or performed by) a variety of apparatuses (e.g., stations). In some aspects, a wireless device or station implemented in accordance with the teachings herein may or may not constitute an access point (a so-called AP) (a so-called non-AP station or STA).

[0074] Although the examples are described in the context of a WiFi network, the invention can be used in any type of wireless network, such as, for example, a mobile cellular network, which implements very similar mechanisms.

[0075] An AP may be configured, implemented, or known as a Node B, Radio Network Controller (RNC), Evolved Node B (eNB), 5G Next Generation Base Station (gNB), Base Station Controller (BSC), Base Transceiver Station (BTS), Base Station (BS), Transceiver Function (TF), Wireless Router, Basic Service Set (BSS), Enhanced Service Set (ESS), Radio Base Station (RBS), or other terminology.

[0076] A non-AP station may be configured, implemented, or known as a subscriber station, subscriber unit, mobile station (MS), remote station, remote terminal, user terminal (UT), user agent, user device, user equipment (UE), user station, or other terminology. In some implementations, an STA may be comprised of a cellular telephone, a cordless telephone, a session initiation protocol (SIP) telephone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless connectivity capabilities, or other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a telephone (e.g., a mobile phone or smartphone), a computer (e.g., a laptop), a tablet, 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 station may be a wireless node. Such wireless nodes may, for example, provide connectivity to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. An AP manages a set of stations that together organize access to the wireless medium for communication. The stations (including the AP) form a service set, hereinafter referred to as a basic service set (BSS) (although other terms may be used). The same physical station acting as an access point may manage two or more BSSs (and thus correspond to multiple WLANs). Each BSS is therefore uniquely identified by a specific basic service set identification (BSSID) and is managed by a separate virtual AP implemented in the physical AP.

[0077] The 802.11 family of standards defines various medium access control (MAC) mechanisms for driving access to the wireless medium.

[0078] Current discussions in Task Group 802.11be, as outlined in the July 2021 IEEE P802.11be / D1.1 draft, introduce multi-link operation (MLO) for MAC layer operation. MLO allows a multi-link device to establish or set up multiple links and operate them simultaneously.

[0079] A multilink device (MLD) is a logical entity that has multiple affiliated stations (STAs) and one medium access control (MAC) service access point (SAP) for a logical link control (LLC) that contains one MAC data service. An access point multilink device (or AP MLD) corresponds to an MLD in which each station (STA) belonging to the MLD is an AP, hence called an "affiliated AP." A non-access point multilink device (or non-AP MLD) corresponds to an MLD in which each station (STA) belonging to the MLD is a non-AP STA, hence called an "affiliated non-AP station." In some literature, the terms "multilink device," "MLD," "multilink logical entity," "ML logical entity (MLE)," "multilink set," and "ML set" are synonyms that designate the same type of ML device.

[0080] Multiple affiliated non-AP stations in a non-AP MLD can establish communication links with multiple affiliated APs in an AP MLD to form a multilink channel.

[0081] Links established for MLD are theoretically independent, meaning that channel access procedures (to the communication medium) and communication are performed independently on each link. Thus, different links may have different data rates (e.g., due to different bandwidths, number of antennas, etc.) and may be used to communicate different types of information (on each particular link).

[0082] Thus, a communication link or "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 belonging to an AP MLD and a non-AP STA belonging to a non-AP MLD.

[0083] Affiliated APs and non-AP stations 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) or other wireless communication standards.

[0084] Multi-link aggregation theoretically allows traffic associated with one MLD to be transmitted across multiple parallel communication links, thereby increasing network capacity and making the best use of available resources.

[0085] From an architectural point of view, an MLD typically includes several radios to implement its affiliated stations, but the number does not necessarily have to be the same as the number of its affiliated stations. In particular, a non-AP MLD may operate with a number of affiliated stations greater than the number of radios (which may be reduced to one).

[0086] From this physical architecture, several Enhanced Multi-Link Operating Modes (EML OM for short) can be defined. P802.11be / D1.1 currently specifies two EML OMs for non-AP MLD:

[0087] The first is the so-called Enhanced Multi-Link Single Radio (EMLSR) mode, which is an operating mode in which a non-AP MLD can simultaneously listen on a set of links (the so-called EMLSR links) for receiving initial control frames (e.g., MU-RTS, BSRP) sent by an AP MLD, and then exchange data frames with the AP MLD via one link at a time (usually corresponding to the link on which the initial control frame was sent).

[0088] The second mode is the so-called Enhanced Multi-Link Multi-Radio (EMLMR) mode, which is an operating mode in which non-AP MLD can aggregate the physical resources of different radios used on different links (so-called EMLMR links) to transmit and receive data up to a predefined number of supported receive / transmit spatial streams (this number is greater than the number of supported receive / transmit spatial streams for each radio).

[0089] Each non-AP MLD can support no EML operation mode, only EMLSR operation mode, only EMLMR mode, or both.

[0090] FIG. 1 illustrates a typical 802.11 network environment including ML transmission in which the present invention may be implemented.

[0091] Wireless communication network 100 includes an AP MLD 110 and two non-AP MLDs 120 and 130. Of course, other numbers of non-AP MLDs that register with and exchange frames with AP MLD 110 are also contemplated.

[0092] The AP MLD 110 has multiple affiliated APs, four affiliated APs 111, 112, 113, and 114 (also referred to as AP1, AP2, AP3, and AP4, respectively), in the exemplary illustration, each operating as an 802.11 AP on an operating channel within a frequency band. Known 802.11 frequency bands include the 2.4 GHz, 5 GHz, and 6 GHz bands. Of course, other frequency bands may be used instead of or in addition to these three frequency bands.

[0093] The non-AP MLDs 120, 130 have multiple affiliated non-AP stations, each operating as an 802.11 non-AP station in the BSS to which it registers (managed by affiliated APs 111, 112, 113, 114). In the exemplary illustration, three non-AP STAs 121, 122, 123 (also referred to as A1, A2, and A3, respectively) belong to the non-AP MLD 120, and four non-AP STAs 131, 132, 133, 134 (also referred to as B1, B2, B3, and B4, respectively) belong to the non-AP MLD 130.

[0094] For illustrative purposes, non-AP MLDs 120 and 130 are multi-radio non-AP MLDs. For example, AP 111 is configured to operate on channel 10, which corresponds to 20 MHz channel operation in the 2.4 GHz frequency band, AP 112 is configured to operate on channels 36-40, which correspond to 40 MHz channel operation in the 5 GHz frequency band, AP 113 is configured to operate on channels 149-153, also corresponding to 40 MHz channel operation in the 5 GHz frequency band, and AP 114 is configured to operate on channel 301, which corresponds to 160 MHz channel operation in the 6 GHz frequency band. In this example, the affiliated stations operate in various frequency bands.

[0095] Each Affiliated AP provides a link to the AP MLD 110 to affiliated non-AP stations. Therefore, each non-AP MLD link can be identified simply by the identifier of the respective Affiliated AP. In this context, each Affiliated AP 111-114 can be identified by an identifier called a "Link ID." The Link ID of each Affiliated AP is unique and does not change during the lifetime of the AP MLD. The AP MLD can assign Link IDs to Affiliated APs by incrementing the ID from 0 (of the first Affiliated AP). Of course, other expressions such as "AP ID" can be used with variations.

[0096] To perform multi-link communication, each non-AP MLD 120, 130 must discover, authenticate, connect, and configure multiple links with the AP MLD 110, with each link established between an affiliated AP of the AP MLD 110 and an affiliated non-AP station of the non-AP MLD. Each link allows separate channel access and frame exchange between the non-AP MLD and the AP MLD based on the supported capabilities exchanged during association.

[0097] The discovery phase is called the ML discovery procedure, and the multilink setup phase (or association phase) is called the ML setup procedure.

[0098] The ML discovery procedure enables a non-AP MLD to discover various links to the wireless communication network 100, i.e., the AP MLD, provided by multiple affiliated APs. Accordingly, the ML discovery procedure attempts to advertise the various affiliated APs in the AP MLD along with their respective network information (e.g., including all or part of their capabilities and operating parameters). Once the non-AP MLD discovers the wireless communication network 100 through the ML discovery procedure, and after the MLD authentication procedure, the non-AP MLD can select a set of candidate link setups between its affiliated non-AP stations and some of the discovered affiliated APs through the ML setup procedure and request the AP MLD 110 to set up these links, which can be accepted or rejected by the AP MLD. If accepted, the non-AP MLD is provided with an association identifier (AID) by the AP MLD, which is used by the affiliated non-APs of the non-AP MLD to wirelessly communicate with the corresponding affiliated APs over multiple links (communication channels).

[0099] For illustrative purposes, in wireless communication network 100, three setup link candidates have been requested from non-AP MLD 120 to AP MLD 110 and accepted by AP MLD 110: a first link 151 between affiliated AP 111 (AP1) and affiliated non-AP STA 121 (A1), a second link 152 between affiliated AP 112 (AP2) and affiliated non-AP STA 122 (A2), and a third link 153 between affiliated AP 114 (AP4) and affiliated non-AP STA 123 (A3).

[0100] Similarly, four setup link candidates have been requested from the multi-radio non-AP MLD 130 to the AP MLD 110 and accepted by the AP MLD 110: a first link 161 between the affiliated AP 111 (AP1) and the affiliated non-AP STA 131 (B1), a second link 162 between the affiliated AP 112 (AP2) and the affiliated non-AP STA 132 (B2), a third link 163 between the affiliated AP 113 (AP3) and the affiliated non-AP STA 133 (B3), and a fourth link 164 between the affiliated AP 114 (AP4) and the affiliated non-AP STA 134 (B4).

[0101] During the ML setup procedure, a non-AP MLD declares some or all of its capabilities, e.g., EMLSR and EMLMR capabilities. Appropriate fields are provided in management frames, e.g., ML Association Request frames, as described below.

[0102] Management frames exchanged during the ML discovery and setup procedures include a new Multi-Link (ML) information element specific to Multi-Link Operation (MLO), called the Multi-Link element. In particular, the ML Association request frame exchanged during the setup procedure is the Association request frame defined in 802.11ax (e.g., IEEE P802.11ax / D8.0 of October 2020) with the addition of the Basic variant Multi-Link element 200 defined in IEEE P802.11be / D1.1, as shown in Figure 2, where non-AP MLDs can declare their EMLSR / EMLMR capabilities.

[0103] The 802.11ax field of the Association Request frame is used in a conventional manner, for example, to request association between an affiliated non-AP station (e.g., B1 131) and a destination affiliated AP (e.g., AP1 111). This defines the requested setup link defined between the affiliated non-AP station and the destination affiliated AP of the ML Association Request frame.

[0104] The MAC header of frame 221 sets the source address TA to the MAC address of the affiliated non-AP station, and the destination address RA to the MAC address of the destination affiliated AP.

[0105] The Basic variant Multi-Link element 200 includes an Element ID field, a Length field (which allows you to know whether there is an optional field and the number of Per-STA profiles in the field), an Element ID Extension field, a Multi-Link Control field, an optional Common Info field 310, and an optional Link Info field.

[0106] The Multi-Link Control field includes a Presence Bitmap subfield that indicates which subfields are included in the Common Info field 210 .

[0107] According to the value specified in the Presence Bitmap subfield, the Common Info field 10 optionally includes an MLD MAC Address subfield, a Link ID Info subfield, a BSS Parameters Change Count subfield, a Medium Synchronization Delay Information subfield, an EML Capabilities subfield 220, and an MLD Capabilities subfield.

[0108] The ML Capabilities subfield 220 is used to declare the capabilities of non-AP MLD regarding enhanced multilink, specifically EMLSR and EMLMR. It includes the EMLSR Support subfield 221, the EMLSR Delay subfield 222, the EMLMR Support subfield 223, the EMLMR Delay subfield 224, the Transition Timeout subfield 225, the Reserved subfield 226, the EMLMR Rx NSS subfield 227, and the EMLMR Tx NSS subfield 228.

[0109] The EMLSR Support subfield 221 is preferably a 1-bit subfield that indicates whether the MLD supports EMLSR operation. The EML SR Support field 251 is set to 1 if the MLD supports EMLSR operation, and is set to 0 otherwise. The EMLSR Delay subfield 222 indicates the MAC padding time of the Padding field of the initial control frame.

[0110] The EMLMR Support subfield 223 is preferably a 1-bit subfield that indicates the MLD's support for EMLMR operation. The EMLMR Support field is set to 1 if the MLD supports EMLMR operation, and is set to 0 otherwise. The EMLMR Delay subfield 224 indicates the minimum padding time required for a non-AP MLD for an EMLMR link switch when operating in EMLMR mode.

[0111] The Transition Timeout subfield 225 indicates the maximum timeout value for activating (or starting) or deactivating (or ending) the EML OM from an EML Operating Mode Notification frame exchange.

[0112] The EMLMR Rx NSS subfield 227 and EMLMR Tx NSS subfield 228 indicate the maximum receive and transmit Nss (number of spatial streams), respectively, supported by non-AP MLD in EMLMR mode.

[0113] Details of these fields are given in the D1.1 standard.

[0114] In one scenario, the non-AP MLDs 120 and 130 support both the EMLSR and EMLMR modes of operation, and therefore, during the ML setup procedure, they transmit an ML Association request frame with both the EMLSR Support subfield 221 and the EMLMR Support subfield 223 of the EML Capabilities subfield 220 of the Common Info field 210 of the Basic Variant Multi-Link 200 set to 1.

[0115] Once the link is set up and capabilities are exchanged, the non-AP MLD 120, 130 performs multi-link operation (MLO) with the affiliated AP MLD 110. One example of MLO is the exchange of frames (uplink and / or downlink communication).

[0116] During MLO, each non-AP MLD can activate EMLSR or EMLMR mode, if appropriate. To activate either EML OM, each non-AP MLD sends an EHT Action frame (typically an EML Operating Mode Notification with the EMLMR Mode subfield or EMLSR Mode subfield equal to 1) to the AP MLD 110. An EML OM frame is identified by the EHT Action field (the octet immediately following the Category field) being set to 1.

[0117] FIG. 3A shows the format of the EML Control field that forms the EML OM Notification frame used to activate or deactivate the EML OM, as defined in the D1.1 standard.

[0118] The 8-bit EML Control field 300 a of the EML OM frame includes a 1-bit EMLSR Mode subfield 311 , a 1-bit EMLMR subfield 312 , and six reserved bits 330 .

[0119] A non-AP MLD that supports EMLSR operation (as declared in its EML capabilities) sets the EMLSR Mode subfield 311 to 1 to request activation of EMLSR mode, which indicates that the non-AP MLD operates in EMLSR mode.

[0120] A non-AP MLD that supports EMLSR operation (as declared in its EML capabilities) sets the EMLSR Mode subfield 311 to 0 to indicate that it does not intend to operate in EMLSR mode.

[0121] The EMLSR Mode subfield 311 is set to 0 for all non-AP MLDs that do not support EMLSR operation.

[0122] Similarly, a non-AP MLD that supports EMLMR operation (as declared in its EML capabilities) sets the EMLMR Mode subfield 312 to 1 to request activation of EMLMR mode, which indicates that the non-AP MLD operates in EMLMR mode.

[0123] A non-AP MLD that supports EMLMR operation (declared in the EML capabilities) sets the EMLMR Mode subfield 312 to 0 to indicate that it does not intend to operate in EMLMR mode.

[0124] The EMLMR Mode subfield 312 is set to 0 for all non-AP MLDs that do not support EMLMR operation.

[0125] To use EMLMR mode and EMLSR mode exclusively, the EMLMR Mode subfield 312 (or EMLSR Mode subfield 311) must be set to 0 for all non-AP MLDs that have the EMLSR Mode subfield 311 (or EMLMR Mode subfield 312) set to 1.

[0126] As will be described below, the AP MLD sets the EMLSR Mode subfield 311 and EMLMR Mode subfield 312 to the values obtained from the received EML Operating Mode Notification frame.

[0127] FIG. 3B illustrates an alternative format for the EML Control field forming the EML OM Notification frame, which is used to activate or deactivate the EML operating mode.

[0128] This alternative format adds an EMLSR Link Bitmap field 321 to the EMLSR Mode subfield 311 and EMLMR Mode subfield 312 described above. A Reserved subfield 330 contains the remaining unused bits.

[0129] The EMLSR Link Bitmap subfield 321 is typically coded as 8 or 16 bits and indicates the subset of valid links that a non-AP MLD uses in EMLSR mode. For example, non-AP MLD A120 may specify links 151 and 152 (and therefore not link 153) for EMLSR mode.

[0130] The i-th bit of the EMLSR Link Bitmap subfield 321 corresponds to the link whose Link ID is equal to i. It is set to 1 to indicate that the link is used by non-AP MLD for EMLSR mode and is a member of the EMLSR link, and is set to 0 otherwise.

[0131] Figure 4 shows a schematic diagram of an exemplary frame sequence for activating or deactivating the EML Operating Mode as defined in the IEEE P802.11be / D1.1 document. Activation of an EML OM by a non-AP MLD is called EML OM Initiation. Deactivation of an EML OM by a non-AP MLD is called EML OM Termination. As shown in the figure, such activation or deactivation of an EML OM is always initiated by a non-AP MLD.

[0132] When a non-AP MLD 401 that supports EML OM (EMLSR / EMLMR modes) intends to operate in one of the EML OM modes, the STA belonging to the non-AP MLD 401 transmits an EML OM Notification frame 420 (FIG. 3A) to the AP belonging to the AP MLD 402. If the non-AP MLD 401 intends to activate EMLSR mode, it sets the EMLSR Mode subfield 311 of the EML Control field 300a of frame 420 to 1, and if it intends to activate EMLMR mode, it sets the EMLMR Mode subfield 312 of the EML Control field 300a of frame 420 to 1. In FIG. 4, the EMLSR Mode subfield is set to 1 to request activation of EMLSR mode.

[0133] An AP belonging to the AP MLD 402 that receives the EML OM Notification frame 420 acknowledges the received frame 420 by transmitting an acknowledgement 430 at the MAC level. After successfully transmitting the EML OM Notification frame 420 (i.e., after transmitting and receiving the acknowledgement 430), the non-AP STA 401 and the AP MLD 402 initialize a Transition Timeout timer 445 using the Transition Timeout subfield value 225 included in the EML Capabilities subfield 220 of the Basic variant Multi-Link element 200 received from the AP MLD during the ML setup procedure.

[0134] The Transition Timeout timer 445 starts counting down from the end of the PPDU containing the acknowledgment 430 of the EML OM Notification frame 420. The Transition Timeout timeout defines the maximum time to receive the EML OM Notification frame 440 from the AP MLD before entering the requested OM.

[0135] The AP MLD 402 may then transmit an EML OM Notification frame 440 to the non-AP STA 401 with the EML Control field set to the same value as the EML Control field 300a of the received EML OM Notification frame 420. The transmission of the EML OM Notification frame 440 occurs before the Transition Timeout timer 445 expires.

[0136] The EML OM Notification frame 440 is acknowledged by the non-AP MLD 401 (acknowledgement 450).

[0137] The EML OM requested by the non-AP STA 401 is activated after the Transition Timeout timer 445 expires or after successful reception of the EML OM Notification frame 440 from the AP MLD 420 .

[0138] Multi-link operation (MLO) is performed using the activated EML OM (EMLSR in this example), for example, frame exchange (uplink and / or downlink communication).

[0139] When a non-AP MLD 401 that supports the EML operation mode (EMLSR / EMLMR) disables the EML mode, the STA belonging to the non-AP MLD 401 sends an EML OM Notification frame 460 (FIG. 3A) to the AP belonging to the AP MLD 402. If the non-AP MLD 401 intends to disable the EMLSR mode, it sets the EMLSR Mode subfield 311 of the EML Control field 300a of frame 460 to 0. If the non-AP MLD 401 intends to disable the EMLMR mode, it sets the EMLMR Mode subfield 312 of the EML Control field 300a of frame 460 to 0. In the example of FIG. 4, the EMLSR Mode subfield is set to 0 to deactivate the currently active EMLSR mode.

[0140] An AP belonging to the AP MLD 402 that receives the EML OM Notification frame 460 acknowledges the received frame 460 by transmitting an acknowledgement 470 at the MAC level. After successfully transmitting the EML OM Notification frame 460 (i.e., after transmitting and receiving the acknowledgement 470), the non-AP STA 401 and the AP MLD 402 initialize a Transition Timeout timer 475 using the Transition Timeout subfield value 225 included in the EML Capabilities subfield 220 of the Basic variant Multi-Link element 200 received from the AP MLD during the ML setup procedure.

[0141] The Transition Timeout timer starts counting down from the end of the PPDU containing the acknowledgement 470 of the EML OM Notification frame 460 .

[0142] The AP MLD 402 may transmit to the non-AP STA 401 an EML OM Notification frame 480 with the EML Control field set to the same value as the EML Control field 300a of the received EML OM Notification frame 460. The transmission of the EML OM Notification frame 480 occurs before the Transition Timeout timer 475 expires.

[0143] The EML OM Notification frame 480 is acknowledged by the non-AP MLD 401 (acknowledgement 490).

[0144] The EML OM requested by the non-AP STA 401 is disabled either upon expiration of the Transition Timeout timer 475 or after successful reception of the EML OM Notification frame 480 from the AP MLD 420 .

[0145] The same sequence as in Figure 4 can be used with the EML Control field format of Figure 3B, where activation of EMLSR mode is done using the EMLSR link specified in the EMLSR Link Bitmap subfield 321.

[0146] The present invention may contemplate using the same subfield 321 to indicate which EMLMR link to use when activating EMLMR mode (EMLMR Mode subfield 312 set to 1 in frame 420). Therefore, subfield 321 may be renamed EML Link Bitmap subfield 521, as shown in Figure 5A.

[0147] In embodiments of the present invention that seek to reduce signaling costs, variations of the above EML Control field format may be used, which are shown in Figures 5B and 5C.

[0148] As shown in these figures, the EMLSR Mode subfield 311 and the EMLMR Mode subfield 312 are combined into a single 1-bit subfield 511 .

[0149] This is possible thanks to a capability declaration exchanged between the non-AP MLD 401 acting as the requesting MLD and the AP MLD 402 acting as the requestee MLD, which declares that the requesting MLD supports Enhanced Multi-Link (EML) operation. As mentioned above, the capability declaration is conveyed in the EML Capabilities field 220, which has a first EMLSR Support subfield 221 for declaring support for EMLSR operation and a second EMLMR Support subfield 223 for declaring support for EMLMR operation. Only one of the two subfields can be enabled, in which case the one-bit subfield 511, the EML Mode subfield, inherits the declared supported mode (either EMLSR or EMLMR): the EML Mode subfield indicates the activation or deactivation of the only supported EML OM declared during the association procedure. This applies, for example, if the requesting non-AP MLD cannot support both EMLSR and EMLMR modes and declares only one of them.

[0150] The EML Control field 300 of an exchanged EML OM frame 420, 440, 460, 480 requesting activation or deactivation of an EML OM includes a 1-bit EML Mode subfield 511 (Fig. 5B) and, optionally, an ML Link Bitmap subfield 521 (Fig. 5C).

[0151] A non-AP MLD 401 that declares support for EMLSR mode simply sets the EML Mode subfield 511 to 1, implying activation of EMLSR mode, and thus the non-P MLD 401 will operate in EMLSR mode. On the other hand, a non-AP MLD 401 sets the EML Mode subfield 511 to 0, indicating deactivation of the current EMLSR mode, and thus indicating that the non-AP MLD 401 will no longer operate in EMLSR mode.

[0152] Similarly, a non-AP MLD 401 that declares it supports EMLMR mode may implicitly indicate activation of EMLMR mode by simply setting the EML Mode subfield 511 to 1, thus indicating that the non-AP MLD 401 will operate in EMLMR mode. On the other hand, a non-AP MLD 401 may set the EML Mode subfield 511 to 0, indicating deactivation of the current EMLMR mode, thus indicating that the non-AP MLD will no longer operate in EMLMR mode.

[0153] Upon sending or receiving a request EML OM Notification frame 420 or 460 or a response EML OM Notification frame 440 or 480, the non-AP MLD 401 and AP MLD 402 activate or deactivate EML OM depending on the combination of the EML Capabilities field 220 and the EML Mode subfield 511. For example, if the 1-bit EML Mode subfield 511 of the request EML OM Notification frame 420 is set to a first value (value 1), the MLD activates EMLSR mode together with other MLDs if the non-AP MLD 401 has declared that it supports EMLSR operation, and activates EMLMR mode together with other MLDs if the non-AP MLD 401 has declared that it supports EMLMR operation.

[0154] Similarly, an MLD can respond to a request EML OM Notification frame 460 requesting deactivation using the EML Mode subfield 511 to determine which modes are supported by the non-AP MLD before deactivating the current EML OM. However, due to the single mode in the mode support declaration, such a request frame may request termination of only the currently active EML OM. Therefore, if the 1-bit EML Mode subfield is set to a second value (value 0) different from the first value, it may be considered to deactivate the currently active EML OM.

[0155] FIG. 5C illustrates the case where a request EML OM Notification frame, eg, frame 420, includes an EML Link Bitmap field 521 signaling a set of links for activating EMLSR or EMLMR OM between two MLDs.

[0156] For example, the EML Link Bitmap subfield 521 indicates a subset of EMLSR links used by the non-AP MLD 401 if the non-AP MLD 401 supports EMLSR mode (only). In such a case, the bit at position i in the EML Link Bitmap subfield 521 corresponds to a link whose Link ID is equal to i, and the bit is set to 1 to indicate that the corresponding link is used by the non-AP MLD 401 in EMLSR mode and is therefore a member of the EMLSR link; otherwise, the bit is set to 0. Similarly, the EML Link Bitmap subfield 521 indicates a subset of valid EMLMR links used by the non-AP MLD 401 if the non-AP MLD 401 supports EMLMR mode (only). In such a case, the bit at position i in the EML Link Bitmap subfield 521 corresponds to a link whose Link ID is equal to i, and the bit is set to 1 to indicate that the corresponding link is used by the non-AP MLD 401 for EMLMR mode and is therefore a member of the EMLMR link; otherwise, the bit is set to 0.

[0157] Another embodiment of the present invention, which seeks to reduce signaling costs, is directed to simplifying the EML OM Notification frame 460, 480 when a link bitmap (EMLSR or EML Link Bitmap subfield 321 / 521) is provided upon activation of the EML OM.

[0158] In this scenario, a first request EML OM Notification frame 420 requesting activation of an EML OM (EMLSR mode or EMLMR mode) is exchanged from a non-AP MLD 401 acting as a requesting MLD to an AP MLD 402 acting as a requested MLD, and the first request EML OM Notification frame includes an EMLSR or EML Link Bitmap field 321 / 521 (FIG. 3B, 5A, or 5C) signaling the set of links to be used by the EML OM to be activated. Data is then exchanged between the two MLDs using the activated EML OM. Next, a second request EML OM Notification frame 460 requesting deactivation of the activated EML OM is exchanged from the non-AP MLD 401 to the AP MLD 402. In these particular embodiments, the second request EML OM Notification frame 460 is deprived of a link bitmap signaling the set of links, ie, it is deprived of the EMLSR or EML Link Bitmap 321 / 521.

[0159] In other words, if the EML Mode subfield 511 is set to 0, i.e., to deactivate an activated EML mode, or if both the EMLSR Mode subfield 311 and the EMLMR Mode subfield 312 are set to 0, the EML Link Bitmap subfield 521 may not be included in the EML Control field.

[0160] In fact, the deactivation of an EML OM does not benefit the set of links, so signaling bits for the link bitmap can be saved (at the time of the deactivation request) thanks to the asymmetry between successive activation request frames 420 and deactivation request frames 460.

[0161] In the current version of IEEE P802.11be / D1.1, the EML OM activation or deactivation process is initiated / triggered by the non-AP MLD 401. The AP MLD 402 simply responds with a response EML OM Notification frame 440, 480 similar to the request EML OM Notification frame 420, 460. In other words, the AP MLD 402 can only accept what the non-AP MLD 401 requests. While the decision by the non-AP MLD 401 is likely optimal given the non-AP MLD's constraints and knowledge of the network, this is not a satisfactory situation because the AP MLD may also have other constraints or knowledge of the network that may require a different decision regarding EML OM. For example, the AP MLD may be aware of the amount of data transmitted on the downlink to non-AP stations, the current interference in the BSS, or the NSTR constraints of a particular AP, such as a soft AP.

[0162] Therefore, the inventors have considered providing more options for AP MLD to contribute to the OM management (activation, deactivation, and even modification) of EML.

[0163] By utilizing the response EML OM Notification frames 440, 480, the embodiments provide the AP MLD with the ability to deny the requested activation or deactivation of an EML OM, which means that the AP MLD, in response to receiving a request EML OM Notification frame 420, 460 from a non-AP MLD requesting activation or deactivation of an EML OM, can send a response EML OM Notification frame to the non-AP MLD denying the activation or deactivation.

[0164] In an embodiment, the signaling of the rejection may simply rely on using the opposite value of the EML / EMLSR / EMLMR Mode subfield 511 / 311 / 312 (depending on the format used) as the value indicated in the request EML OM Notification frame.

[0165] 6A illustrates such an embodiment in an exemplary sequence of frames for activating an EML OM. Of course, a similar approach can be used to reject deactivation of an EML OM.

[0166] First, a non-AP MLD 401 that supports EML operations (either EMLSR or EMLMR, or both) sends a request EML OM Notification frame 420 to the AP MLD 402, requesting activation of EML OM. This is a similar step to that described above, based on the EML Control field format of, for example, Figure 3A or Figure 5B, and means that the EML Mode subfield 511 or the EMLSR Mode subfield 311 or the EMLMR Mode subfield 312 is set to 1 to activate EML OM, or these subfields are set to 0 to deactivate the current EML OM.

[0167] In response to receiving such a frame, the AP MLD 402 determines whether the requested request (activation in this example, but also applicable to deactivation) is acceptable from its point of view. The decision process in the AP MLD is not a critical aspect of this embodiment. Therefore, any method may be used to make the decision. If the requested request is acceptable, conventional processing (see FIG. 4) can be performed.

[0168] On the other hand, if the AP MLD 402 does not agree with the request, it can reject the request by preparing and sending a reject EML OM Notification frame 640 using the same EML Control field format. The EML OM Notification frame 640 from the AP MLD 402 is a "reject" frame because it contains an EML Mode subfield 511 / 311 / 312 set to the opposite value (e.g., 0) of the corresponding EML Mode subfield in the request EML OM Notification frame 620 for the requested EML OM.

[0169] This inverse value allows a non-AP MLD 401 that receives a response EML OM Notification frame 620 from the AP MLD 402 to become aware of the rejection from the AP MLD 402 early on.

[0170] As shown, the response EML OM Notification frame 640 is preferably included in the same Physical Protocol Data Unit (PPDU) 600 as the (MAC) acknowledgment 630 to the request EML OM Notification frame 620. Indeed, by determining the AP MLD rejection early, the non-AP MLD 401 can prevent its Transition Timeout timer 445, 475 from starting, thereby avoiding automatic activation of the requested EML OM despite the pending rejection. Thus, the non-AP MLD 401 and the AP MLD 402 do not start their local Transition Timeout timers when they send (in the case of AP MLD) or receive (in the case of non-AP MLD) an acknowledgment 630 to the request EML OM Notification frame 420 included in the same Physical Protocol Data Unit (PPDU) 600 as the response EML OM Notification frame 640 rejecting activation. This action aborts the initiation of an ongoing EML OM.

[0171] The non-AP 401 may then send an acknowledgement 450 to the frame 640 denying the activation.

[0172] Figure 6B shows a variation in which a link bitmap is provided in the EML OM Notification frame, described below with respect to an EML OM activation request, but also applicable to deactivation. Any of the EML Control field formats 300b (Figure 3B), 300c (Figure 5A), and 300e (Figure 5C) can be used.

[0173] Initially, a non-AP MLD 401 that supports EML operations (either EMLSR or EMLMR, or both) still sends a request EML OM Notification frame 420 to the AP MLD 402 requesting activation of an EML OM, and such frame 420 includes a link bitmap 321 / 521 indicating the link to be used for the EML OM to be activated. In this example, the link bitmap "CCC" is specified.

[0174] In response to receiving such a frame, the AP MLD 402 decides whether the requested request (activation in the example, but also applicable to deactivation) is acceptable from its point of view. The decision process in the AP MLD is not a critical aspect of the present embodiment. Therefore, any approach for making the decision can be considered. In particular, the decision can be made regarding the action to activate the EML OM and / or regarding the set of links signaled in the link bitmap "CCC" for activation.

[0175] If the requested request is accepted, the conventional process (see FIG. 4) can be implemented.

[0176] On the other hand, if the AP MLD 402 does not agree with the request, it can reject the request by preparing and sending a reject EML OM Notification frame 640 using the same EML Control field format. The EML OM Notification frame 640 from the AP MLD 402 is a "reject" frame because it contains an EML Mode subfield 511 / 311 / 312 set to the opposite value (e.g., 0) of the corresponding EML Mode subfield in the request EML OM Notification frame 620 for the requested EML OM.

[0177] This inverse value allows a non-AP MLD 401 that receives a response EML OM Notification frame 620 from the AP MLD 402 to become aware of the rejection from the AP MLD 402 early on.

[0178] Furthermore, if the AP MLD decides to reject the proposed links in the link bitmap "CCC" based on the fact that the proposed links are deemed inappropriate, the AP MLD 402 can make a counter-proposal for a set of links. In this regard, the AP MLD 402 includes in the responding EML OM Notification frame 640 a Link Bitmap field 321 / 521 signaling a proposed set of links for activating EML OM between the two MLDs. The proposed links may be links for which the AP MLD is ready to accept EML OM activation. Any method for determining such a set of "acceptable" links is contemplated. In the illustrated example, the proposed set of alternative links is shown as a link bitmap "BBB," which is actually different from the initial set of links "CCC" signaled in the request EML OM Notification 420.

[0179] As mentioned above, the response EML OM Notification frame 640 is preferably included in the same Physical Protocol Data Unit (PPDU) 600 as the (MAC) acknowledgement 630 to the request EML OM Notification frame 620. This is again to avoid starting the MLD Transition Timeout timers 445, 475, and therefore automatically initiating the requested EML OM despite a pending rejection.

[0180] The non-AP MLD 401 may then send an acknowledgment 450 to the frame 640 denying activation.

[0181] Upon recognizing that the AP MLD 402 is ready to accept the set of links "BBB", the non-AP MLD 401 may decide to send the AP MLD 402 a new request EML OM Notification frame 420' requesting activation of the EML OM, with such frame 420 this time including the proposed set of links "BBB".

[0182] This request is accepted by the AP MLD 402, so the subsequent steps are conventional with an acknowledgement 430 starting a Transition Timeout timer 445, an EML OM Notification frame 640' identical to the requesting EML OM Notification frame 420', and a final acknowledgement 450.

[0183] This FIG. 6B embodiment illustrates a first exemplary level of an AP MLD's ability to propose or make proposals to non-AP MLDs for EML OM management.

[0184] Embodiments of the present invention also provide the ability for an AP MLD to propose to a non-AP MLD the activation and deactivation of an EML OM in line with the non-AP MLD's EML capabilities declared during the ML setup procedure. Such proposals contrast with the D1.1 standard, in which only the non-AP MLD initiates the EML OM activation / deactivation procedure.

[0185] These embodiments rely on an EML OM Notification frame transmitted from an AP MLD to a non-AP MLD, which defines (i.e., contains or notifies or signals) a proposal from the AP MLD to activate, deactivate, or modify the EML OM. This frame is transmitted spontaneously by the AP MLD at its own initiative, as it is merely a proposal or suggestion to take EML OM management action. Thus, spontaneously, i.e., without direction from the non-AP MLD, the non-AP MLD receives from the AP MLD an EML OM Notification frame defining a proposal from the AP MLD to spontaneously activate, deactivate, or modify the EML OM. For example, this EML OM Notification frame precedes a request EML OM Notification frame 420 from the non-AP MLD.

[0186] These embodiments are illustrated by Figures 7A and 7A for activating an EML OM, by Figure 8 for deactivating a currently activated EML OM, and by Figure 9 for modifying a currently activated EML OM.

[0187] The AP MLD knows which non-AP MLDs support EML operations, specifically EMLSR and / or EMLMR modes, through the EML capabilities exchanged during the non-AP MLD-AP MLD association.

[0188] As shown in Figure 7A, an EML OM Initiation Proposal from an AP MLD includes transmitting an EML OM Notification frame 700 from the AP MLD 402 to a non-AP MLD (e.g., non-AP MLD 401) proposing activation of EML OM. Any of the EML Control field formats of Figures 3A and 5B can be used. Because it is a proposal for EML OM activation, the EML OM Notification frame 700 has the EML Mode subfield 511, EMLSR Mode subfield 311, or EMLMR Mode subfield 312 set to 1 to activate EML OM supported by the target non-AP MLD.

[0189] This transmission may be in response to a locally detected triggering event, e.g., a change in network conditions that causes the AP MLD to propose EMLSR and / or EMLMR mode to some or all of the non-AP MLDs that belong to it. A triggering event excludes the receipt of an EML OM Notification frame requesting the same activation from a non-AP MLD.

[0190] Because the EML OM Notification frame 700 is received by the non-AP MLD 401 without the non-AP MLD 401 having previously sent an EML OM Notification frame, it is considered by the non-AP MLD 401 to be a proposal or proposal from the AP MLD 402. Therefore, the non-AP MLD 401 can evaluate the opportunity to follow the AP MLD 402's proposal / proposal and, therefore, can request activation of the EML OM according to the proposal (e.g., activate EMLSR mode if the AP MLD 402 proposed activation of EMLSR mode).

[0191] If the non-AP MLD 401 evaluates the opportunity positively, it responds to the received (proposal) frame 700 by sending a request EML OM Notification frame 420 to the AP MLD 402 requesting activation of the EML OM, and then initiates any procedure for processing such a frame 420 (e.g., the conventional processing of FIG. 4 or processing with a rejection as in FIG. 6A or 6B). In the illustrated example, the subsequent procedure is the conventional procedure with an acknowledgement 430 that starts a Transition Timeout timer 445 (triggering the actual activation of the requested EML OM), an EML OM Notification frame 440 identical to the request EML OM Notification frame 420 (in particular, the same EML Mode subfield 311 / 312 / 511), and a final acknowledgement 450.

[0192] 7B shows a variation in which a link bitmap is provided in an EML OM Notification frame 700' to suggest a set of links to be used to activate the EML OM. Any of the EML Control field formats 300b (FIG. 3A), 300c (FIG. 5A), and 300e (FIG. 5C) may be used.

[0193] Again, the EML OM Initiation Proposal from the AP MLD includes the transmission of an EML OM Notification frame 700' from the AP MLD 402 to the non-AP MLD 401, proposing the activation of EML OM. Because it is a proposal for EML OM activation, the EML OM Notification frame 700' includes the EML Mode subfield 511, EMLSR Mode subfield 311, or EMLMR Mode subfield 312 set to 1 to activate EML OM supported by the target non-AP MLD. Additionally, the EML OM Notification frame 700' includes the EMLSR / EML EMLSR / EML Link Bitmap field 321 / 521, which signals the proposal of a link for activating EML OM between the two MLDs. In this example, the link bitmap "AAA" corresponding to the proposed link set is signaled in the subfield 321 / 521.

[0194] The transmission may be in response to a triggering event as described above.

[0195] If the non-AP MLD 401 positively evaluates the opportunity to activate the EML OM proposed by the AP MLD 402, it responds to the received (proposal) frame 700' by sending a request EML OM Notification frame 720 to the AP MLD 402 requesting activation of the EML OM, and then initiates any procedure for processing such a frame 420 (e.g., the conventional processing of FIG. 4 or processing with rejection as in FIG. 6A or 6B). The request EML OM Notification frame 720 also includes a link bitmap 321 / 521.

[0196] In some embodiments where the non-AP MLD 401 follows the AP MLD's proposal, the link bitmap 321 / 521 in frame 720 corresponds to the same proposed link set as in frame 700'. In the case of Figure 7B, frame 720 also signals link bitmap "AAA".

[0197] In some embodiments (not shown) in which the non-AP MLD 401 estimates that a different set of links should be used for EML OM activation, the link bitmap 321 / 521 in frame 720 corresponds to a different set of links (e.g., "BBB") than the proposed set of links ("AAA") defined in frame 700'.

[0198] In the illustrated example, the subsequent steps are the conventional steps with an acknowledgement 430 that starts a Transition Timeout timer 445 (which triggers the actual activation of the requested EML OM), an EML OM Notification frame 440 identical to the requested EML OM Notification frame 420 (in particular, the same EML Mode subfield 311 / 312 / 511), and a final acknowledgement 450.

[0199] Turning now to an EML OM Termination Proposal from an AP MLD, as shown in Figure 8, this involves the transmission of an EML OM Notification frame 800 from the AP MLD 402 to the non-AP MLD 401 proposing deactivation of the currently active EML OM. Either of the EML Control field formats of Figures 3A and 5B can be used. Because this is a proposal for EML OM deactivation, the EML OM Notification frame 700 has the EML Mode subfield 511, or the EMLSR Mode subfield 311 and the EMLMR Mode subfield 312, set to 0 to deactivate the currently active EML OM.

[0200] This transmission may be in response to a locally detected triggering event, e.g., a change in network conditions that causes the AP MLD to propose termination of active EMLSR and / or EMLMR mode with some or all of the non-AP MLDs to which it belongs. This triggering event excludes the receipt of an EML OM Notification frame requesting the same deactivation from a non-AP MLD.

[0201] Because the EML OM Notification frame 800 is received by the non-AP MLD 401 without the non-AP MLD 401 having previously sent an EML OM Notification frame, the non-AP MLD 401 considers it to be a suggestion or proposal from the AP MLD 402. Thus, the non-AP MLD 401 can evaluate the opportunity to follow the AP MLD 402's suggestion / proposal and, therefore, can request deactivation of the currently active EML OM according to the AP MLD 402's proposal (e.g., deactivate the currently active EML OM mode if the AP MLD 402 proposed deactivation of such mode).

[0202] If the non-AP MLD 401 evaluates the opportunity positively, it responds to the received (proposal) frame 800 by sending a request EML OM Notification frame 460 to the AP MLD 402 requesting deactivation of the EML OM, and then initiates any procedure for processing such a frame 460 (e.g., the conventional processing of FIG. 4 or processing with a rejection as in FIG. 6A or 6B). In the illustrated example, the subsequent procedure is the conventional procedure with an acknowledgement 470 that starts a Transition Timeout timer 475 (triggering the actual deactivation of the requested EML OM), an EML OM Notification frame 480 identical to the requested EML OM Notification frame 460 (in particular, with the same EML Mode subfield 311 / 312 / 511), and a final acknowledgement 490.

[0203] Turning now to the EML OM Modification Proposal from the AP MLD, as shown in Figure 9, this proposal calls for modifying the currently active EML OM for a given link set to the same EML OM (e.g., EMLSR or EMLMR) but a different link set. This process involves the AP MLD 402 sending an EML OM Notification frame 900 to the non-AP MLD 401 proposing a modification of the currently active EML OM. Any of the EML Control field formats of Figures 3B, 5A, and 5C can be used. In effect, the proposed modification amounts to proposing a new set of links compared to the links already used by the currently active mode.

[0204] Because the current EML OM Notification frame signaling cannot directly signal a change in EML OM, the change process may be a two-step process of deactivating the currently active EML OM followed by activating the same EML OM on a different link set. In other words, in response to the received EML OM Notification frame 900, the non-AP MLD 401 transmits a first request EML OM Notification frame 460 requesting deactivation of the currently active EML OM (identified in frame 900), and then transmits a second request EML OM Notification frame 420 requesting activation of the same EML OM on a link set different from the link of the currently active EML OM. The "same" EML OM refers to EMLMR mode if the deactivated currently active EML OM was an EMLMR, and refers to EMLSR mode if the deactivated currently active EML OM was an EMLSR. Preferably, to take into account the link suggestions from the AP MLD 402 , the different set of links in the second EML OM Notification frame 420 is the set of links suggested by the AP MLD 402 in frame 900 .

[0205] In the illustrated example, AP MLD 402 proposes a set of links corresponding to link bitmap "CCC." Thus, EML OM Notification frame 900 includes EML Link Bitmap subfield 521 set to "CCC."

[0206] If, in response to frame 900, non-AP MLD 401 evaluates the AP MLD's proposal as important, it sends to AP MLD 402 a request EML OM Notification frame 460 requesting deactivation of the currently active EML OM, and then initiates any procedure for handling such a frame 460 (e.g., the conventional process of FIG. 4). In the illustrated example, the subsequent procedure is the conventional procedure, with an acknowledgement 470 starting a Transition Timeout timer 475 (which triggers the actual deactivation of the requested EML OM), an EML OM Notification frame 480 identical to request EML OM Notification frame 460 (in particular, the same EML Mode subfield 311 / 312 / 511), and a final acknowledgement 490.

[0207] It then sends a request EML OM Notification frame 420 to AP MLD 402 requesting activation of the proposed set of claims in the same EML OM as the proposed set of claims, and initiates any procedure for processing that frame 420 (e.g., the conventional processing of FIG. 4 or processing with rejection as in FIG. 6A or 6B). The request EML OM Notification frame 420 includes a link bitmap 321 / 521 set to the proposed bitmap "CCC".

[0208] In the illustrated example, the subsequent steps are the conventional steps involving an acknowledgement 430 initiating a Transition Timeout timer 445 (which triggers the actual activation of the requested EML OM), an EML OM Notification frame 440 identical to the requested EML OM Notification frame 420 (in particular, the same EML Mode subfield 311 / 312 / 511 and the same link bitmap), and a final acknowledgement 450.

[0209] In a variant not shown, the non-AP MLD 401 may respond to frame 900 by sending an EML OM Notification frame 900' containing "change" signaling (e.g., specific flags) with the set of proposed links "CCC", in order to avoid the two-stage approach described above.

[0210] Another way in which the AP MLD provides hints or suggestions to the non-AP MLD is described with reference to Figure 10. In this scenario, the non-AP MLD still initiates the activation of the EML OM, but either requests the AP MLD for a set of links to use, or provides a set of links that does not satisfy the AP MLD.

[0211] In this scenario, the AP MLD reacts to a request frame from a non-AP MLD: In response to receiving a first request EML OM Notification frame from the non-AP MLD requesting activation of EML OM, the AP MLD sends a response EML OM Notification frame to the non-AP MLD signaling a proposed set of links for activating EML OM.

[0212] As shown in the figure, the non-AP MLD 401 sends a first request EML OM Notification frame 1000 to the AP MLD 401, requesting activation of the EML OM. Any of the EML Control field formats of Figures 3B, 5A, and 5C can be used, for example, frame 1020 includes an EML Link Bitmap subfield 521.

[0213] In some embodiments (the one shown), the EML Link Bitmap subfield 521 of frame 1020 is empty or has a predefined bit pattern (all bits set to 0, with bits corresponding to non-existent enabled link sets set to 1) that prompts the AP MLD 402 to indicate (in its response) which link to use for the requested EML OM.

[0214] In other embodiments (not shown), the EML Link Bitmap subfield 521 of frame 1000 may be set to a predetermined set of links (ie, several valid links are signaled).

[0215] A conventional acknowledgement 430 is sent from the AP MLD 402. To avoid activating EML OM on an empty link set, the MLD, as an exception to the conventional approach, does not start a local Transition Timeout timer 445 based on the acknowledgement 430. This mechanism may be based on the link bitmap in frame 1020: the MLD does not start its local Transition Timeout timer when it sends / receives an acknowledgement to the requesting EML OM Notification frame 1020 if the latter contains an EML Link Bitmap field 521 for signaling an empty link.

[0216] The AP MLD 402 then sets its EML Mode subfield 311 / 312 / 511 to the same activation value (here, 1) as in the request frame 1020 and sends a response EML OM Notification frame 1040 to the non-AP MLD 401 signaling the set of links that the AP MLD 402 proposes to activate the requested EML OM. In this example, the set of links corresponding to link bitmap "BBB" is proposed. A conventional acknowledgement 450 is sent by the non-AP 402. The proposed set of links is different from the set of links optionally specified in frame 1020.

[0217] The non-AP MLD 401 can then evaluate the opportunity to activate an EML OM using the link set proposed by the AP MLD 402. If negative, nothing further happens. If positive, in response to receiving the reply EML OM Notification frame 1040, it sends a second request EML OM Notification frame 420 requesting activation of an EML OM using the proposed set of links "BBB." The procedure followed to process such a frame 420 may be the conventional processing of FIG. 4 (or alternatively, processing with rejection as in FIG. 6A or 6B): an acknowledgement 430 that starts a Transition Timeout timer 445 (triggering the actual activation of the requested EML OM), followed by an EML OM Notification frame 440 identical to the request EML OM Notification frame 420 (in particular, with the same EML Mode subfield 311 / 312 / 511) and a final acknowledgement 450.

[0218] Figure 11 shows a schematic diagram of the EMLMR-enabled architecture of MLD, taking the example of two associated non-AP STAs sharing antenna resources when EMLMR mode is enabled.

[0219] The architecture consists of two radio stacks, one for each non-AP STA.

[0220] The radio stack includes a full 802.11be MAC module 1100a or 1100b (which exchanges data with upper layers), a full 802.11be PHY module 1105a or 1105b connected to the MAC module, a radio frequency chain 1110a or 1110b connected to the PHY module, an EMLMR switch 1115 shared by the two radio stacks and configured to perform antenna resource aggregation when EMLMR mode is activated, and an antenna array 1120a or 1120b.

[0221] The diagram on the bottom left shows the functionality when EMLMR mode is disabled. A common EMLMR switch 1115 connects each antenna array to its RF chain. Each radio stack is therefore complete and can support each link, for example using a 2x2 MIMO antenna configuration. As shown in the diagram, two links are available.

[0222] The bottom right diagram shows the functionality when EMLMR mode is activated. A common EMLMR switch 1115 aggregates antenna resources to the first link by connecting the antenna array 1120b of the second radio stack to the RF chain 1110a of the first radio stack. Thus, the first radio stack operates in a 4x4 MIMO antenna configuration, improving the throughput of link 1. However, link 2 becomes unavailable because its antenna array 1120b is unavailable to the second radio stack.

[0223] Although the illustrated antenna resource aggregation takes all antenna resources from the second radio stack in EMLMR mode, it is conceivable that the EMLMR mode may aggregate only a portion of these antenna resources with the first radio stack.

[0224] 12 shows a schematic diagram of a communication device 1200 of a wireless network, typically one of the MLDs described above, configured to implement at least one embodiment of the present invention. The communication device 1200 may preferably be a device such as a microcomputer, a workstation, or a lightweight handheld device. The communication device 1200 preferably comprises a communication bus 1213 connected thereto: a central processing unit 1201 such as a processor, denoted as CPU; a memory 1203 for storing executable code of a method or method steps according to an embodiment of the present invention, as well as registers adapted to record variables and parameters necessary for the implementation of the method; and At least two communication interfaces 1202 and 1202' connected via transmit and receive antennas 1204 and 1204', respectively, to a wireless communication network, for example a communication network according to one of the standards of the IEEE 802.11 family.

[0225] Preferably, a communications bus 1213 provides for communication and interoperability between various elements included in or connected to communications device 1200. The representation of a bus is not limiting, and in particular a central processing unit is operable to communicate instructions to any element of communications device 1200 directly or by way of another element of communications device 1200.

[0226] The executable code can be stored in a memory, either read-only, on a hard disk, or on a removable digital medium, such as a disk. According to any variant, the executable code of the program can be received by the communication network via the interface 1202 or 1202', so as to be stored in the memory of the communication device 1200 before being executed.

[0227] In one embodiment, the device is a programmable apparatus that uses software to implement embodiments of the invention, however, embodiments of the invention may alternatively be implemented in whole or in part in hardware (e.g., in the form of an application specific integrated circuit or ASIC).

[0228] Although the present invention has been described with reference to particular embodiments, it is not limited to those embodiments, and modifications within the scope of the invention will be apparent to those skilled in the art.

[0229] Many further modifications and variations will be suggested to those skilled in the art upon reference to the exemplary embodiments described above, but these embodiments 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 interchanged where appropriate.

[0230] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do 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. 1. A method for communicating in a wireless network, comprising: In the requestee multi-link device (MLD), receiving a first request EML OM Notification frame from a requesting MLD requesting activation of an Enhanced Multi-Link Operating Mode (EML OM), the first request EML OM Notification frame including a field signaling a set of links to be used in the EML OM; exchanging data with the requesting MLD using the activated EML OM; receiving, from the requesting MLD, a second request EML OM Notification frame requesting deactivation of the activated EML OM, the second request EML OM Notification frame not having a field signaling a set of links. Communication method.

2. 1. A method for communicating in a wireless network, comprising: In the requesting multi-link device (MLD), sending a first request EML OM Notification frame to a requested MLD requesting activation of an Enhanced Multi-Link Operating Mode (EML OM), the first request EML OM Notification frame including a field signaling a set of links to be used in the EML OM; exchanging data with the requested MLD using the activated EML OM; sending, to the requested MLD, a second request EML OM Notification frame requesting deactivation of the activated EML OM, the second request EML OM Notification frame not having a field signaling a set of links. Communication method.

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