Apparatus and method for coordinating shared transmission opportunities in wireless network

Abstract

A shared access point (AP) (110) is configured to share at least a portion of a transmit opportunity (TXOP) with one or more shared APs (120) within a set of multiple APs (M-APs) to participate in coordinated transmissions. The shared AP (110) comprises a processing circuit (111), and the processing circuit (111) is used for generating an M-AP trigger frame. And a communication interface (113) for transmitting an M-AP trigger frame to the shared AP (120) in the set of M-APs. The M-AP trigger frame is used to request the shared AP (120) to initiate a coordination related procedure to one or more non-AP sites associated with the shared AP (120) and / or to one or more OBSS non-AP sites associated with one or more other shared APs within the M-AP set, and to send a completion notification frame to the shared AP (110). The communication interface (113) is further configured to receive a completion notification frame from the shared AP (120), the completion notification frame indicating completion of the coordination-related process.

Description

Technical Field

[0001] The present invention relates to wireless communications, and more particularly to an apparatus and method for coordinating shared transmission opportunities in a wireless communication network. Background Art

[0002] IEEE 802.11-based WLANs (also known as Wi-Fi networks) are becoming more popular than ever before. The 802.11 family of standards continues to expand through revisions to previous 802.11 standards and the introduction of new generations of standards, providing new and improved technical features for WLAN technology.

[0003] 802.11be (also known as "Wi-Fi 7") introduces multi-AP (M-AP) coordinated transmission, in which a group of access points (APs) can initiate concurrent frame exchanges within a limited time period, and one or more APs in the group can share one or more transmission opportunities (TXOPs) during the limited time period. A group of APs that decide to cooperate and perform coordinated transmission is called an M-AP set. Summary of the invention

[0004] An object of the present invention is to provide an improved device and method for APs to coordinate shared transmission opportunities in a wireless communication network (especially a wireless communication network based on IEEE 802.11).

[0005] The above and other objects are achieved by the subject matter of the independent claims. Other implementations are apparent from the dependent claims, the description and the drawings.

[0006] According to a first aspect, a shared access point (AP) is provided, wherein the shared AP is used to share at least a portion of a transmission opportunity (TXOP) with one or more shared APs in a multi-AP (Multi-AP, M-AP) set to participate in coordinated transmission. The shared AP includes: a processing circuit, which is used to generate an M-AP trigger frame; a communication interface, which is used to send the M-AP trigger frame to the shared AP in the M-AP set. The M-AP trigger frame is used to request the shared AP to initiate a sequential pre-transmission coordination-related process to one or more BSS non-AP sites associated with the shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs running according to the same coordination protocol in the same M-AP set, and to send a completion notification frame to the shared AP. The communication interface is also used to receive a completion notification frame from the shared AP, which indicates that the shared AP has completed the sequential pre-transmission coordination-related process.

[0007] In another possible implementation manner, the M-AP trigger frame includes an M-AP set identifier used to indicate the M-AP set.

[0008] In another possible implementation, the M-AP trigger frame includes a coordination protocol identifier in the M-AP set. The coordination protocol identifier identifies one of multiple coordination protocols in the M-AP set, and the sharing AP and the shared AP operate according to the coordination protocol identified by the coordination protocol identifier in the M-AP set.

[0009] In another possible implementation manner, the M-AP trigger frame includes an identifier of the shared AP.

[0010] In another possible implementation manner, the M-AP trigger frame includes an indication for indicating the type of the sequential pre-transmission coordination related process.

[0011] In another possible implementation manner, the M-AP trigger frame includes information about one or more parameters of a sequential pre-transmission coordination-related process.

[0012] In another possible implementation, the M-AP trigger frame includes an indication to the shared AP to initiate sending a completion notification frame to the shared AP, where the completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

[0013] In another possible implementation, the M-AP trigger frame includes an indication for indicating a maximum time period for performing sequential pre-sending coordination-related procedures to one or more non-AP sites associated with a shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set.

[0014] In another possible implementation, when the communication interface does not receive a frame indicating completion of the sequential operation from the shared AP within the maximum time period indicated in the M-AP trigger frame, the communication interface is used to send another M-AP trigger frame to the shared AP within the M-AP set, wherein the other M-AP trigger frame is used to request the shared AP to initiate a sequential pre-sending coordination-related process to one or more non-AP sites associated with the shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set.

[0015] In another possible implementation, another M-AP trigger frame is further used to request the shared AP to send another completion notification frame to the sharing AP, where the other completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

[0016] In another possible implementation, when the communication interface does not receive a completion notification frame indicating the completion of a sequential pre-transmission coordination-related process from a shared AP within a maximum time period indicated in the M-AP trigger frame, the communication interface is used to send another M-AP trigger frame to another shared AP operating according to the same coordination protocol within the same M-AP set, wherein the other M-AP trigger frame is used to request another shared AP to initiate a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the other shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set.

[0017] In another possible implementation, another M-AP trigger frame is further used to request another shared AP to send another completion notification frame to the sharing AP, where the other completion notification frame indicates that another shared AP completes the sequential pre-transmission coordination-related process.

[0018] In another possible implementation manner, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed includes an M-AP set identifier used to indicate the M-AP set.

[0019] In another possible implementation, the completion notification frame indicating completion of the sequential pre-transmission coordination-related process includes a coordination protocol identifier in the M-AP set. The coordination protocol identifier identifies one of multiple coordination protocols in the M-AP set, and the sharing AP and the shared AP operate according to the coordination protocol identified by the coordination protocol identifier in the M-AP set.

[0020] In another possible implementation manner, the completion notification frame indicating the completion of the sequential pre-transmission coordination-related process includes an indication for indicating a status of the sequential pre-transmission coordination-related process executed by the shared AP.

[0021] In another possible implementation manner, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed includes an indication for indicating another time period for requesting the shared AP to perform the sequential pre-transmission coordination-related process.

[0022] In another possible implementation manner, the indication for indicating another time period for requesting the shared AP to perform a sequential pre-transmission coordination-related process includes a value of the other time period.

[0023] In another possible implementation manner, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed includes information obtained by the shared AP during execution of the sequential pre-transmission coordination-related process.

[0024] In another possible implementation, in response to receiving a completion notification frame indicating completion of a sequential pre-transmission coordination-related process from a shared AP, the communication interface is used to send another M-AP trigger frame to the shared AP or another shared AP operating according to the same coordination protocol within the M-AP set. The other M-AP trigger frame requests the shared AP or another shared AP to initiate a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP, to one or more non-AP sites associated with another shared AP, and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set.

[0025] In another possible implementation, another M-AP trigger frame is further used to request the shared AP or another shared AP to send another completion notification frame to the sharing AP, where the other completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

[0026] According to a second aspect, a method for operating a shared access point (AP) is provided, wherein the shared AP is used to share at least a portion of a transmission opportunity (TXOP) with one or more shared APs in a multi-AP (M-AP) set to participate in coordinated transmission. The method comprises the following steps:

[0027] Generate M-AP trigger frame;

[0028] Sending an M-AP trigger frame to a shared AP in the M-AP set, wherein the M-AP trigger frame is used to request the shared AP to initiate a sequential pre-transmission coordination-related process to one or more BSS non-AP sites associated with the shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol in the same M-AP set, and further requesting the shared AP to send a completion notification frame to the sharing AP; and

[0029] A completion notification frame is received from the shared AP, where the completion notification frame indicates that the shared AP completes the sequential pre-transmission coordination-related process.

[0030] The method according to the second aspect of the present invention can be performed by the shared AP according to the first aspect of the present invention. Therefore, other features of the method according to the second aspect of the present invention are directly implemented by the functions of the shared AP according to the first aspect of the present invention and its different implementations described above and below.

[0031] According to a third aspect, a shared access point (AP) is provided. The shared AP is used to participate in coordinated transmission using at least a portion of the transmission opportunity (TXOP) shared by the shared APs in a multi-AP (Multi-AP, M-AP) set, wherein the shared AP comprises: a communication interface for receiving an M-AP trigger frame from a shared AP in the M-AP set; and a processing circuit for initiating a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol in the same M-AP set in response to receiving the M-AP trigger frame. The communication interface is also used to send a completion notification frame to the shared AP, the completion notification frame indicating that the shared AP completes the sequential pre-transmission coordination-related process.

[0032] In another possible implementation manner, the M-AP trigger frame includes an M-AP set identifier used to indicate the M-AP set.

[0033] In another possible implementation, the M-AP trigger frame includes a coordination protocol identifier in the M-AP set. The coordination protocol identifier identifies one of multiple coordination protocols in the M-AP set, and the sharing AP and the shared AP operate according to the coordination protocol identified by the coordination protocol identifier in the M-AP set.

[0034] In another possible implementation manner, the M-AP trigger frame includes an indication for indicating the type of the sequential pre-transmission coordination related process.

[0035] In another possible implementation manner, the M-AP trigger frame includes an identifier of the shared AP.

[0036] In another possible implementation manner, the M-AP trigger frame includes information about one or more parameters of a sequential pre-transmission coordination-related process.

[0037] In another possible implementation, the M-AP trigger frame includes an indication to the shared AP to initiate sending a completion notification frame to the shared AP, where the completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

[0038] In another possible implementation, the M-AP trigger frame includes an indication for indicating a maximum time period for performing sequential pre-sending coordination-related procedures to one or more non-AP sites associated with a shared AP and / or to one or more OBSS non-AP sites associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set.

[0039] In another possible implementation, when the sequential pre-transmission coordination-related process is not completed within the maximum time period indicated in the M-AP trigger frame, the completion indication frame includes an indication of other time periods for requesting the shared AP to perform the sequential pre-transmission coordination-related process.

[0040] In another possible implementation manner, the indication for indicating another time period for requesting the shared AP to perform a sequential pre-transmission coordination-related process includes a value of the other time period.

[0041] In another possible implementation manner, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed includes an M-AP set identifier used to indicate the M-AP set.

[0042] In another possible implementation, the completion notification frame indicating completion of the sequential pre-transmission coordination-related process includes a coordination protocol identifier in the M-AP set. The coordination protocol identifier identifies one of multiple coordination protocols in the M-AP set, and the sharing AP and the shared AP operate according to the coordination protocol identified by the coordination protocol identifier in the M-AP set.

[0043] In another possible implementation manner, the completion notification frame indicating the completion of the sequential pre-transmission coordination-related process includes an indication for indicating a status of the sequential pre-transmission coordination process executed by the shared AP.

[0044] In another possible implementation manner, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed includes information obtained by the shared AP during execution of the sequential pre-transmission coordination-related process.

[0045] According to a fourth aspect, a method for operating a shared access point (AP) is provided, wherein the shared AP is used to participate in coordinated transmission using at least a portion of a transmission opportunity (TXOP) shared by a shared AP in a multi-AP (M-AP) set. The method comprises the following steps:

[0046] Receiving an M-AP trigger frame from a shared AP in the M-AP set;

[0047] In response to receiving the M-AP trigger frame, initiating a sequential pre-transmission coordination-related process to one or more non-AP stations associated with the shared AP and / or to one or more OBSS non-AP stations associated with one or more other shared APs operating according to the same coordination protocol within the same M-AP set; and

[0048] A completion notification frame is sent to the shared AP, where the completion notification frame indicates that the shared AP has completed the sequential pre-sending coordination-related process.

[0049] The method according to the fourth aspect of the present invention can be performed by the shared AP according to the third aspect of the present invention. Therefore, other features of the method according to the fourth aspect of the present invention are directly implemented by the functions of the shared AP according to the third aspect of the present invention and its different implementation modes described above and below.

[0050] According to a fifth aspect, a computer program product is provided, the computer-readable storage medium comprising a computer-readable storage medium for storing program code, and when the program code is executed by a computer or a processor, the computer or the processor executes the method according to the second aspect or the method according to the fourth aspect.

[0051] The following drawings and description set forth one or more embodiments in detail. Other features, objects, and advantages are apparent in the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which:

[0053] Figure 1 An exemplary wireless communication network including a sharing AP and a shared AP for CoBF transmission according to one embodiment is shown;

[0054] Figure 2 A schematic diagram showing an exemplary CoBF scheme based on a sequential detection process;

[0055] Figure 3 A schematic diagram showing a shared AP according to one embodiment and a general sequential pre-transmission coordination-related process performed by a shared AP according to one embodiment is shown;

[0056] Figure 4 A schematic diagram showing a shared AP according to one embodiment and a sequential pre-transmission coordination process with a time limit rule performed by a shared AP according to one embodiment;

[0057] Figure 5 A flow chart showing a method for operating a shared AP according to one embodiment is shown;

[0058] Figure 6 A flow chart of a method for operating a shared AP according to an embodiment is shown.

[0059] In the following, identical reference signs refer to identical or at least functionally equivalent features. DETAILED DESCRIPTION

[0060] In the following description, reference is made to the accompanying drawings that form a part of the present invention, which illustrate specific aspects of embodiments of the present invention or specific aspects in which embodiments of the present invention may be used by way of illustration. It should be understood that embodiments of the present invention may be used in other aspects and include structural or logical changes that are not depicted in the accompanying drawings. Therefore, the following specific embodiments should not be understood in a restrictive sense, and the scope of the present invention is defined by the appended claims.

[0061] For example, it should be understood that the disclosure related to the described method may also be applicable to the corresponding device or system for performing the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units (e.g., functional units) to perform the described one or more method steps (e.g., one unit performs one or more steps, or multiple units perform one or more steps of multiple steps respectively), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units (e.g., functional units), the corresponding method may include a step to perform the function of one or more units (e.g., one step performs the function of one or more units, or multiple steps perform the function of one or more units of multiple units respectively), even if such one or more steps are not explicitly described or illustrated in the drawings. In addition, it should be understood that, unless otherwise stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.

[0062] Coordinated BF (CoBF) is a coordination scheme proposed for the next generation of Wi-Fi for coordinated data transmission by multiple APs at the same time. The coordination scheme assumes that each participating AP has the ability to precode the signal it transmits so that the mutual interference between the AP and the STAs of the overlapping BSS (OBSS) is minimized (also known as approaching zero) during the coordinated transmission. Similarly, in all other coordination schemes, CoBF is initialized by a sharing AP, which proposes other APs (called shared APs) to transmit simultaneously. The resources proposed in this case are spatial streams, where the sharing AP allocates a specific corresponding number of spatial streams to each shared AP. CoBF can use other previous sequential sounding processes to estimate the channel between AP and STA, however, this article does not discuss this in more detail. Based on the estimated channel parameters, the AP can construct a precoder matrix to generate beams to non-AP STAs from the same BSS participating in the coordinated transmission, and generate zero values ​​to STAs from the OBSS participating in the current CoBF transmission.

[0063] Figure 1An exemplary wireless communication network 100 for CoBF transmission according to one embodiment is shown, including a sharing AP 110 and a shared AP 120. The sharing AP 110 is configured to share at least a portion of a transmission opportunity (TXOP) with a shared AP 120 operating according to the same coordination protocol within a multi-AP set (also referred to as an M-AP set) to participate in a coordinated beamforming (CoBF) transmission. Figure 1 In the exemplary embodiment shown, the sharing AP 110 is used to communicate with stations 115 a , 115 b , and 115 c associated with the sharing AP 110 , and the shared AP 120 is used to communicate with stations 125 a , 125 b associated with the shared AP 120 .

[0064] like Figure 1 As shown, the shared AP 110 includes a processing circuit 111 and a communication interface 113 (especially a wireless communication interface 113 according to the IEEE802.11 standard framework). The processing circuit 111 can be implemented in hardware and / or software form, and can include a digital circuit, or both an analog circuit and a digital circuit. The digital circuit may include components such as an application-specific integrated circuit (ASIC), a field-programmable array (FPGA), a digital signal processor (DSP) or a general-purpose processor. The shared AP 110 may also include a memory 115, which is used to store executable program code. When the executable program code is executed by the processing circuit 111, the shared AP 110 performs the functions and methods described herein.

[0065] Similarly, Figure 1The shared AP 120 shown includes a processing circuit 121 and a communication interface 123 (especially a wireless communication interface 123 according to the IEEE 802.11 standard framework). The processing circuit 121 can be implemented in hardware and / or software form, and can include a digital circuit, or both an analog circuit and a digital circuit. The digital circuit may include components such as an application-specific integrated circuit (ASIC), a field-programmable array (FPGA), a digital signal processor (DSP) or a general-purpose processor. The shared AP 120 may also include a memory 125, which is used to store executable program code, and when the executable program code is executed by the processing circuit 121, the shared AP 120 performs the functions and methods described herein.

[0066] Before describing different embodiments of the shared AP 110 and the shared AP 120 in more detail, some technical background and terminology of wireless devices related to the IEEE 802.11 standard WLAN framework are introduced below using one or more of the following abbreviations:

[0067] BFR Beamforming Report

[0068] BFRP Beamforming Report Poll trigger frame

[0069] BSS Basic Serving Set

[0070] CoBF Coordinated Beamforming

[0071] NDP Null Data PPDU

[0072] NDPA NDP Announcement

[0073] M-AP Multi-AP

[0074] OBSS Overlapping BSS

[0075] SCI Shared AP Complete Indication

[0076] STA Station (Generally, it can be AP STA or non-AP STA)

[0077] TF Trigger Frame

[0078] TXOP Transmission opportunity

[0079] Figure 2 A schematic diagram of a CoBF scheme based on a sequential detection process is shown. 802.11be introduces a multi-AP (Multi-AP, M-AP) coordinated transmission operation, in which multiple access points (Access Point, AP) share resources so that they can transmit in parallel in multiple BSSs and use their resources more efficiently. Some coordination schemes involve pre-transmission sequential processes that should be performed before coordinating data transmission. The purpose of these processes is to collect some parameters or manage the network.

[0080] For example, Figure 2 The CoBF scheme shown requires a sequential sounding process, in which the shared AP obtains sounding feedback parameters, i.e., sounding feedback parameters collected from BSS and / or OBSS STAs through beamforming report (BFR) frames 217, 227. These can be triggered by the corresponding shared AP by sending a beamforming report poll trigger (BFRP) frame 215, 225, which is triggered after the Null Data Packet Announcement (NDPA) frame 211, 221 to notify the relevant STAs that need to measure channel parameters using Null Data PPDU (NDP) 213, 223.

[0081] These processes may consist of multiple stages, wherein in each stage a single shared AP is triggered by the sharing AP using a regular M-AP trigger frame 201 to perform its operation.

[0082] The entire process is only completed if each stage is completed successfully. Therefore, the shared AP should indicate to the sharing AP that the current stage is completed, and some information can also be provided according to the coordination scheme. If a stage is not completed, the shared AP should point this out and / or request more resources to complete all necessary operations. In addition, at each stage, the shared AP should be the only manager of resources. This means that the first shared AP should define the maximum time period allocated to the current stage. In addition, in order to prevent deadlock, the shared AP should regain control of the resources at the end of the time period. It should be understood that at least some of the above requirements are crucial to a successful and efficient coordinated pre-send order process.

[0083] The embodiments disclosed herein provide a new frame that can support a sequential pre-transmission process, with the following properties: (i) each stage of the sequential process is completely controlled by the shared AP; (ii) the shared AP can indicate the completion of the stage of the sequential process or request more resources to complete the stage of the sequential process; (iii) each stage may have a time limit, and the shared AP (as the TXOP holder) automatically regains control of the resources at the end of the time period allocated for the sequential process. This scheme will be described in more detail in the following embodiments.

[0084] Figure 3 A schematic diagram of a general pre-transmission order coordination related process performed by a sharing AP 110 according to one embodiment and a shared AP 120 according to one embodiment is shown. The main idea is to design two frames 301, 303, which are capable of managing the pre-transmission order coordination related process.

[0085] As will be described in more detail below, Figure 1 and Figure 3The shared access point (AP) 110 shown in the figure is used to share at least a part of a transmission opportunity (TXOP) with one or more shared APs 120 in a multi-AP (M-AP) set to participate in coordinated transmission. The processing circuit 111 of the shared AP 110 is used to generate an M-AP trigger frame 301, and the communication interface 113 of the shared AP 110 is used to send the M-AP trigger frame 301 to the shared AP 120 in the M-AP set, wherein the M-AP trigger frame 301 is used to request the shared AP 120 to initiate a coordination-related process to one or more non-AP sites 125a associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120' in the M-AP set, and send a completion notification frame 303 to the shared AP 110. The communication interface 113 is further configured to receive a completion notification frame 303 from the shared AP 120 and the shared AP 120 ′, the completion notification frame indicating that the coordination-related process is completed.

[0086] Therefore, in Figure 3 In the illustrated embodiment, the shared AP 110 operates according to a coordination protocol with the shared AP1 120 and another shared AP2 120' to implement a coordinated scheme of coordinated beamforming. The non-AP station STA1 125a is associated with the shared AP1 120. Therefore, the non-AP station STA1 is regarded as a BSS station of the shared AP1 120 and an OBSS station of another shared AP2 120'. In order to apply the coordinated transmission of both the shared AP1 120 and the shared AP2 120' (together with the shared AP 110), each of the shared APs 120, 120' needs to collect channel parameters from the non-AP station STA1 125a. Therefore, the shared AP 110 may assign a sequential sounding process to the shared AP1 120 to collect channel parameters from the non-AP site STA1 125a (in order to steer the beam with relevant data for the non-AP site), and also assign a sequential sounding process to the shared AP2 120′ to collect channel parameters from the non-AP site STA1 125a (in order to generate a zero value to the non-AP site STA1 125a when the non-AP site STA1 125a sends data to its own BSS non-AP site).

[0087] As a supplement to the shared AP 110, Figure 1 and Figure 3The shared access point (AP) 120 shown in the figure is used to participate in coordinated transmission by using at least a portion of the transmission opportunity (TXOP) shared by the shared AP 110 in the multi-AP (Multi-AP, M-AP) set. The communication interface 123 of the shared AP 120 is used to receive the M-AP trigger frame 301 from the shared AP 110 in the M-AP set, and the processing circuit 121 of the shared AP 120 is used to perform a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120' in the M-AP set in response to receiving the M-AP trigger frame 301. The communication interface 123 of the shared AP 120 is also used to send a completion notification frame 303 to the shared AP 110, and the completion notification frame indicates that the coordination-related process is completed.

[0088] Therefore, the completion notification frame 303 (which may also be referred to as the shared AP completion indication frame 303 or simply the SCI frame 303) is sent as a completion indication to the shared AP 110, which previously sent the new variant of the M-AP trigger frame 301. The M-AP trigger frame 301 can be used to trigger a single shared AP 120, 120' at a time to perform its pre-transmission coordination related process phase. As described in more detail below, the completion notification frame 303 can indicate the completion of the triggering phase of the pre-transmission process, provide the shared AP 110 with scheme related information, or request more time to complete the pre-transmission process (if necessary).

[0089] It should be understood that once a portion of the transmission opportunities have been shared, the allocation of STAs to the roles of the sharing AP 110 and the shared APs 120, 120' may change.

[0090] The M-AP Trigger Frame 301 may include information, ie an indication of one or more parameters regarding coordination related procedures. The indication of a new M-AP Trigger Frame TF 301 variant may include a currently reserved option or a special indication of the TF Type field.

[0091] The M-AP trigger frame 301 may include an identifier of a shared AP 120, 120' within the M-AP set. Thus, with such indication of a single triggered shared AP 120, 120', only a single shared AP 120, 120' may be triggered by the M-AP trigger frame 301.

[0092] The M-AP trigger frame 301 may include an indication for indicating the type of the coordination process, which may be a sequential process type indication, for example, NDP sounding, collecting a power headroom value indicating the process type triggered by the current M-AP TF 301 .

[0093] The M-AP trigger frame 301 may include an indication for indicating a time period for performing a sequential pre-transmission coordination-related procedure to one or more non-AP sites associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120' within the M-AP set. Thus, a duration allocated for a particular phase is provided, which may be a time period allocated for the current phase of the sequential pre-transmission coordination-related procedure. Rules related to the indication will be described below.

[0094] The M-AP trigger frame 301 may include a coordination protocol identifier within the M-AP set, wherein the coordination protocol identifier identifies one of a plurality of coordination protocols within the M-AP set, and the sharing AP 110 and the shared AP 120 operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set. In addition, the M-AP trigger frame 301 may include an M-AP set identifier for indicating the M-AP set.

[0095] Therefore, the coordination scheme related information may be a new field in the M-AP TF 301, which may include information and / or parameters related to a specific sequential process triggered by the M-AP TF 301. For different coordination schemes and sequential processes, the subfields of this field may be different.

[0096] The M-AP trigger frame 301 may include an indication to the shared AP 120 to initiate sending a completion notification frame 303 to the sharing AP 110, the completion notification frame indicating that the pre-transmission coordination related process is completed.

[0097] The completion notification frame 303 may need to be sent by the shared AP 120, 120' within the time period allocated for the current phase of the sequential pre-transmission coordination related process, for example, as defined in the M-AP trigger frame 301. The completion notification frame 303 may include indications and parameters described in more detail below.

[0098] The completion notification frame 303 may include an M-AP set identifier, that is, an M-AP set ID for indicating an M-AP set.

[0099] The completion notification frame 303 may include a coordination protocol identifier, i.e., a coordination protocol ID within the M-AP set, wherein the coordination protocol identifier identifies one of multiple coordination protocols within the M-AP set, and the sharing AP 110 and the shared AP 120 operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set.

[0100] The completion notification frame 303 may include an indication of the status of the pre-transmission coordination related process performed by the shared AP 120. The status may indicate that the stage is completed, incomplete, or aborted. It should be understood that the status indication is only information provided to the sharing AP 110, but no action is determined by the shared AP 120, 120'.

[0101] The completion notification frame 303 may include an indication for indicating a request for an additional time period for the sequential pre-transmission coordination-related process to be performed by the shared AP 120. The indication for indicating the request for an additional time period may be linked to an indication for indicating the status of the coordination-related process, indicating that the stage is not completed. The indication for indicating a request for an additional time period for the sequential pre-transmission coordination-related process to be performed by the shared AP 120 may include a value for the additional time period. Thus, the shared AP 120 may request an additional time, specifying a time period in units of time.

[0102] The completion notification frame 303 may include information obtained by the shared AP 120 during the execution of the sequential pre-transmission coordination-related process. The information may be coordination scheme related information, wherein in some coordination schemes / processes, the shared AP 120 may include information obtained during the sequential process. For different coordination schemes and sequential processes, the subfields of this field may include different content. For example, the completion notification frame 303 may contain information corresponding to the information received in the BFR 217, 227.

[0103] After receiving the M-AP TF 301, the shared AP 120 may perform the steps required by the corresponding sequential process. In addition, the shared AP 120 may indicate the stage status using the completion notification frame 303 when the stage ends.

[0104] As a supplement, after sending the M-AP TF 301, the shared AP 110 may wait for a completion notification frame 303 indicating the end of the triggering phase. In addition, the shared AP 110 may apply a time counter until the time counter times out, as defined by the shared AP 120 requesting other time or as defined in the M-AP TF 301. After receiving the completion notification frame 303, if the completion notification frame 303 is received from the shared AP 120', 120' (i.e., the last shared AP 120, 120') or if an unexpected situation occurs, the shared AP 110 may trigger the next phase or complete the process if completion is indicated. In addition, if more time is requested, the shared AP 110 may be used to pre-send the same phase of the coordination-related process in the newly allocated time period with the same shared AP 120, 120' triggering order.

[0105] In response to receiving the completion notification frame 303 from the shared AP 120, the communication interface 113 of the shared AP 110 may be configured to send another M-AP trigger frame 301 to the shared AP 120 or another shared AP 120′ within the M-AP set, wherein the another M-AP trigger frame 301 requests the shared AP 120 or another shared AP 120′ to initiate sequential pre-transmission coordination-related procedures to one or more non-AP sites associated with the shared AP, to one or more non-AP sites associated with another shared AP 120′, and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120′ operating according to the same coordination protocol within the same M-AP set.

[0106] Another M-AP trigger frame 301 may also be used to request the shared AP 120 or another shared AP 120' to send another completion notification frame 303 to the sharing AP 110, the other completion notification frame indicating that the sequential pre-transmission coordination related process is completed.

[0107] Figure 4 A schematic diagram of a shared AP 110 according to one embodiment and a sequential pre-transmission coordination-related process with a time limit rule performed by a shared AP 120 according to one embodiment is shown.

[0108] In the event that the communication interface 113 of the sharing AP 110 does not receive a frame indicating completion of the sequential operation from the shared AP 120 within the time period 401 indicated in the M-AP trigger frame 301, the communication interface 113 of the sharing AP 110 may be used to send another M-AP trigger frame 301 to the shared AP 120 within the M-AP set. The another M-AP trigger frame 301 may be used to request the shared AP 120 to initiate a sequential pre-transmission coordination-related procedure to one or more non-AP sites associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120 operating according to the same coordination protocol within the M-AP set.

[0109] If the time period 401 allocated for the current sequential pre-transmission coordination-related phase has ended, then neither of the shared APs 120 , 120 ′ can further transmit frames. Then, the shared APs 120 , 120 ′ can wait for the next M-AP trigger frame 301 transmitted by the shared AP 110 .

[0110] In the case that the communication interface 113 of the sharing AP 110 does not receive the completion notification frame 303 from the shared AP 120 within the time period 401 indicated in the M-AP trigger frame 301, the communication interface 113 may be used to send another M-AP trigger frame 301 to another shared AP 120′ in the M-AP set, wherein the another M-AP trigger frame 301 is used to request the another shared AP 120′ to initiate a sequential pre-sending coordination-related process to one or more non-AP sites associated with the another shared AP 120′ and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120 operating according to the same coordination protocol in the M-AP set. The another M-AP trigger frame 301 may also be used to request the shared AP 120′ to send another completion notification frame 303 to the sharing AP 110, the another completion notification frame indicating that the coordination-related process is completed.

[0111] Therefore, if Figure 4 As shown, if the time period 401 allocated for the current phase has ended and the sharing AP 110 has not received the completion notification frame 303, but the completion notification frame may have been sent by the shared AP 120, the current phase may be marked as incomplete and the next phase may be executed.

[0112] In the case that the communication interface 113 of the sharing AP 110 does not receive the completion notification frame 303 indicating the completion of the sequential operation from the shared AP 120 within the time period 401 indicated in the previous M-AP trigger frame 301, the communication interface 113 may be used to send another M-AP trigger frame 301 to the shared AP 120 in the M-AP set, wherein the another M-AP trigger frame 301 is used to request the shared AP 120 to initiate a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120′ in the M-AP set. The another M-AP trigger frame 301 may also be used to request the shared AP 120 to send another completion notification frame 303 to the sharing AP 110, the another completion notification frame indicating the completion of the coordination-related process.

[0113] Therefore, if Figure 4 As further shown, if the time period 401 allocated for the current phase has ended and the completion notification frame 303 has not been received by the sharing AP 110, but may have been sent by the shared AP 120, the current phase may be marked as incomplete and may be retriggered. Depending on the type of the process, the process may stop.

[0114] In the case that the sequential pre-transmission coordination-related process is not completed within the time period 401 indicated in the M-AP trigger frame 301, the completion notification frame 303 may include an indication for indicating a further time period for requesting the sequential pre-transmission coordination-related process to be performed by the shared AP. The indication for indicating a further time period for requesting the sequential pre-transmission coordination-related process to be performed by the shared AP 120 may include a value for the further time period required. Therefore, if more time is required, the shared AP 120 may send another completion notification frame 303.

[0115] Therefore, the shared AP 110 can efficiently manage the sequential pre-transmission coordination process using the new frames 301, 303 and the above rules. In addition, due to the above time limit rules, the sequential process will not deadlock. The proposed frames 301, 303 can be used to perform different M-AP sequential pre-transmission coordination related processes, such as sequential sounding, sequential primary channel switching for Co-OFDMA, or power control information collection for Co-UL MU-MIMO.

[0116] Figure 5A flow chart of a method 500 for operating a shared AP 110 according to one embodiment is shown. As described above, the shared access point 110 is used to share at least a portion of the obtained transmission opportunity (TXOP) with one or more shared APs 120 in a multi-AP (Multi-AP, M-AP) set to participate in coordinated transmission. The method 500 includes a step 501 of generating an M-AP trigger frame 301 by the shared AP. The method 500 also includes a step 503 for sending the M-AP trigger frame 301 to the shared AP 120 operating according to the coordination protocol in the M-AP set, wherein the M-AP trigger frame 301 is used to request the shared AP 120 to initiate a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP 120 and / or to one or more OBSS non-AP sites associated with one or more other shared APs 120' operating according to the coordination protocol in the M-AP set, and optionally indicates to send a completion notification frame 303 to the shared AP 110. The method 500 further comprises step 505 for receiving a completion notification frame 303 from the shared AP 120 , the completion notification frame indicating that the sequential pre-transmission coordination-related process performed by the shared AP 120 is completed.

[0117] Since the method 500 may be implemented by the shared AP 110, other features of the method 500 flow directly from the functionality of the shared AP 110 and its different embodiments described above and below.

[0118] Figure 6 A flow chart of a method 600 for operating a shared AP 120 according to one embodiment is shown. As described above, the shared access point (AP) 120 is used to participate in coordinated transmission using at least a portion of a transmission opportunity (TXOP) obtained and shared by a shared AP 110 operating according to a coordination protocol within a multi-AP (M-AP) set. The method 600 includes step 601 for receiving an M-AP trigger frame 301 from a shared AP 110 operating according to a coordination protocol within the M-AP set. The method 600 also includes step 603 for initiating a sequential pre-transmission coordination-related process to one or more non-AP stations associated with the shared AP 120 and / or to one or more OBSS non-AP stations associated with one or more other shared APs 120' operating according to a coordination protocol within the M-AP set in response to receiving the M-AP trigger frame 301. The method 600 also includes step 605 for sending a completion notification frame 303 to the shared AP 110, the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed.

[0119] Since the method 600 may be implemented by the shared AP 120, other features of the method 600 come directly from the functionality of the shared AP 120 and its various embodiments described above and below.

[0120] Those skilled in the art will understand that the "blocks" ("units") in the various figures (methods and devices) represent or describe the functions of an embodiment of the present invention (and not necessarily independent "units" in hardware or software), thereby equally describing the functions or features of the device embodiments and the method embodiments (unit = step).

[0121] In the multiple embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described are merely exemplary. For example, unit division is only a logical function division, and other division methods may be used in actual implementation. For example, multiple units or components may be merged or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be implemented through some interfaces. The indirect coupling or communication connection between devices or units can be implemented electronically, mechanically or in other ways.

[0122] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one location, or may be distributed across multiple network units. Some or all of the units may be selected based on actual needs to achieve the purpose of the embodiment.

[0123] Furthermore, the functional units in the embodiments disclosed herein may be integrated into one processing unit, or each of these units may exist physically separately, or two or more units may be integrated into one unit.

Claims

1. A shared access point (AP) (110), characterized in that: The shared AP (110) is used to share at least a portion of a transmission opportunity (TXOP) with one or more shared APs (120) operating according to the coordination protocol within a multi-AP (M-AP) set to participate in coordinated transmission, wherein the shared AP (110) includes: A processing circuit (111) for generating an M-AP trigger frame (301); and A communication interface (113) is used to send the M-AP trigger frame (301) to the shared AP (120) in the M-AP set, wherein the M-AP trigger frame (301) is used to request the shared AP (120) to initiate a sequential pre-transmission coordination-related process to one or more non-AP sites associated with the shared AP (120) and / or to one or more OBSS non-AP sites associated with one or more other shared APs (120') operating according to the coordination protocol in the M-AP set, and to send a completion notification frame (303) to the shared AP (110); The communication interface (113) is further used to receive the completion notification frame (303) from the shared AP (120), wherein the completion notification frame (303) indicates that the sequential pre-transmission coordination-related process is completed.

2. The shared AP (110) according to claim 1, characterized in that: The M-AP trigger frame (301) includes an M-AP set identifier for indicating the M-AP set.

3. The shared AP (110) according to claim 1 or 2, characterized in that: The M-AP trigger frame (301) includes a coordination protocol identifier within the M-AP set, wherein the coordination protocol identifier identifies one of multiple coordination protocols within the M-AP set, and wherein the sharing AP (110) and the shared AP (120) operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set.

4. The shared AP (110) according to any one of the preceding claims, characterized in that: The M-AP trigger frame (301) includes an indication for indicating the type of the sequential pre-transmission coordination related process.

5. The shared AP (110) according to claim 4, characterized in that: The M-AP trigger frame (301) includes information about one or more parameters of the sequential pre-transmission coordination related process.

6. The shared AP (110) according to any one of the preceding claims, characterized in that: The M-AP trigger frame (301) includes an instruction to the shared AP (120) to initiate sending the completion notification frame (303) to the shared AP (110), wherein the completion notification frame (303) indicates that the sequential pre-transmission coordination-related process is completed.

7. The shared AP (110) according to any one of the preceding claims, characterized in that: The M-AP trigger frame (301) includes the identifier of the shared AP.

8. The shared AP (110) according to any one of the preceding claims, characterized in that: The M-AP trigger frame (301) includes an indication for indicating a time period for performing the sequential pre-transmission coordination-related process to the one or more non-AP sites associated with the shared AP (120) and / or to the one or more OBSS non-AP sites associated with the one or more other shared APs (120') operating according to the coordination protocol within the M-AP set.

9. The shared AP (110) according to claim 8, characterized in that: In the case where the communication interface (113) does not receive the completion notification frame (303) indicating completion of the sequential pre-transmission coordination-related process from the shared AP (120) within the time period indicated in the previous M-AP trigger frame (301), the communication interface (113) is used to send another M-AP trigger frame (301) to the shared AP (120) in the M-AP set, wherein the another M-AP trigger frame (301) is used to request the shared AP (120) to initiate the sequential pre-transmission coordination-related process to the one or more non-AP sites associated with the shared AP (120) and / or to the one or more OBSS non-AP sites associated with the one or more other shared APs (120') operating according to the coordination protocol in the M-AP set.

10. The shared AP (110) according to claim 9, characterized in that: The another M-AP trigger frame (301) is also used to request the shared AP (120) to send another completion notification frame (303) to the sharing AP (110), and the another completion notification frame (303) indicates that the sequential pre-transmission coordination related process is completed.

11. The shared AP (110) according to claim 8, characterized in that: In the case where the communication interface (113) does not receive the completion notification frame (303) from the shared AP (120) within the time period indicated in the M-AP trigger frame (301), the communication interface (113) is used to send another M-AP trigger frame (301) to another shared AP (120') in the M-AP set, wherein the other M-AP trigger frame (301) is used to request the other shared AP (120') to initiate the sequential pre-transmission coordination-related process to one or more non-AP sites associated with the other shared AP (120') and / or to the one or more OBSS non-AP sites associated with the one or more other shared APs (120) operating according to the coordination protocol in the M-AP set.

12. The shared AP (110) according to claim 11, characterized in that: The another M-AP trigger frame (301) is also used to request the another shared AP (120') to send another completion notification frame (303) to the shared AP (110), wherein the another completion notification frame (303) indicates that the sequential pre-transmission coordination-related process is completed.

13. The shared AP (110) according to any one of the preceding claims, characterized in that: The completion notification frame (303) includes a coordination protocol identifier within the M-AP set, wherein the coordination protocol identifier identifies one of multiple coordination protocols within the M-AP set, and the sharing AP (110) and the shared AP (120) operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set.

14. The shared AP (110) according to any one of the preceding claims, characterized in that: The completion notification frame (303) includes an M-AP set identifier for indicating the M-AP set.

15. The shared AP (110) according to any one of the preceding claims, characterized in that: The completion notification frame (303) includes an indication for indicating the status of the sequential pre-transmission coordination related process performed by the shared AP (120).

16. The shared AP (110) according to any one of the preceding claims, characterized in that: The completion notification frame (303) includes an indication for indicating a further time period for requesting the shared AP (120) to perform the sequential pre-transmission coordination related process.

17. The shared AP (110) according to claim 16, characterized in that: The indication for indicating the other time period for requesting the shared AP (120) to perform the sequential pre-transmission coordination related process includes the value of the other time period required.

18. The shared AP (110) according to any one of the preceding claims, characterized in that: The completion notification frame (303) includes information obtained by the shared AP (120) during the execution of the sequential pre-transmission coordination-related process.

19. The shared AP (110) according to any one of the preceding claims, characterized in that: In response to receiving the completion notification frame (303) from the shared AP (120), the communication interface (113) is used to send another M-AP trigger frame (301) to the shared AP (120) or another shared AP (120') within the M-AP set, wherein the another M-AP trigger frame (301) requests the shared AP (120) or the other shared AP (120') to initiate the sequential pre-transmission coordination-related process to the one or more non-AP stations associated with the shared AP and / or to one or more OBSS non-AP stations associated with the one or more other shared APs operating according to the coordination protocol within the same M-AP set.

20. The shared AP (110) according to claim 19, characterized in that: The another M-AP trigger frame (301) is also used to request the shared AP (120) or the another shared AP (120') to send another completion notification frame (303) to the shared AP (110), wherein the another completion notification frame (303) indicates that the sequential pre-transmission coordination-related process is completed.

21. A method (500) for operating a shared access point (AP) (110), characterized in that: The shared AP (110) is used to share at least a portion of a transmission opportunity (TXOP) with one or more shared APs (120) in a multi-AP (M-AP) set to participate in coordinated transmission, wherein the method (500) includes: Generate (501) an M-AP trigger frame (301); sending (503) the M-AP trigger frame (301) to a shared AP (120) operating according to the coordination protocol within the M-AP set, wherein the M-AP trigger frame (301) is used to request the shared AP (120) to initiate a sequential pre-transmission coordination-related process to one or more non-AP stations associated with the shared AP (120) and / or to one or more OBSS non-AP stations associated with one or more other shared APs (120') operating according to the coordination protocol within the M-AP set, and to send a completion notification frame (303) to the shared AP (110); and The completion notification frame (303) is received (505) from the shared AP (120), the completion notification frame indicating that the sequential pre-transmission coordination-related process is completed.

22. A shared access point (AP) (120), characterized in that: The shared AP (120) is used to participate in coordinated transmission by utilizing at least a portion of transmission opportunities (TXOPs) obtained and shared by the shared APs (110) operating according to the coordination protocol within a multi-AP (M-AP) set, wherein the shared AP (120) comprises: a communication interface (123) for receiving an M-AP trigger frame (301) from the shared AP (110) operating according to the coordination protocol within the set of M-APs; and a processing circuit (121) for initiating, in response to receiving the M-AP trigger frame (301), a sequential pre-transmission coordination-related process to one or more non-AP stations associated with the shared AP (120) and / or to one or more OBSS non-AP stations associated with one or more other shared APs (120') operating according to the coordination protocol within the M-AP set; The communication interface (123) is further used to send a completion notification frame (303) to the shared AP (110), wherein the completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

23. The shared AP (120) according to claim 22, characterized in that: The M-AP trigger frame (301) includes a coordination protocol identifier within the M-AP set, wherein the coordination protocol identifier identifies one of multiple coordination protocols within the M-AP set, and the sharing AP (110) and the shared AP (120) operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set.

24. The shared AP (120) according to claim 22 or 23, characterized in that: The M-AP trigger frame (301) includes an M-AP set identifier for indicating the M-AP set.

25. The shared AP (120) according to any one of claims 22 to 24, characterized in that: The M-AP trigger frame (301) includes an indication for indicating the type of the sequential pre-transmission coordination related process.

26. The shared AP (120) according to claim 25, characterized in that: The M-AP trigger frame (301) includes information about one or more parameters of the sequential pre-transmission coordination related process.

27. The shared AP (120) according to any one of claims 22 to 26, characterized in that: The M-AP trigger frame (301) includes an instruction to the shared AP (120) to initiate sending the completion notification frame (303) to the shared AP (110), wherein the completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

28. The shared AP (120) according to any one of claims 22 to 27, characterized in that: The M-AP trigger frame (301) includes the identifier of the shared AP.

29. The shared AP (120) according to any one of claims 22 to 28, characterized in that: The M-AP trigger frame (301) includes an indication for indicating a time period for performing the sequential pre-transmission coordination-related process to the one or more non-AP sites associated with the shared AP (120) and / or to the one or more OBSS non-AP sites associated with the one or more other shared APs (120') operating according to the coordination protocol within the M-AP set.

30. The shared AP (120) according to claim 29, characterized in that: In the case that the sequential pre-transmission coordination-related process is not completed within the time period indicated in the M-AP trigger frame (301), the completion indication frame includes an indication of another time period for requesting the shared AP to perform the sequential pre-transmission coordination-related process.

31. The shared AP (120) according to claim 30, characterized in that: The indication for indicating the other time period for requesting the shared AP (120) to perform the sequential pre-transmission coordination related process includes the value of the other time period.

32. The shared AP (120) according to any one of claims 22 to 31, characterized in that: The completion notification frame (303) includes a coordination protocol identifier within the M-AP set, wherein the coordination protocol identifier identifies one of multiple coordination protocols within the M-AP set, and the sharing AP (110) and the shared AP (120) operate according to the coordination protocol identified by the coordination protocol identifier within the M-AP set.

33. The shared AP (120) according to any one of claims 22 to 32, characterized in that: The completion notification frame (303) includes an M-AP set identifier for indicating the M-AP set.

34. The shared AP (120) according to any one of claims 22 to 33, characterized in that: The completion notification frame (303) includes an indication for indicating a status of the sequential pre-transmission coordination related process performed by the shared AP.

35. The shared AP (120) according to any one of claims 22 to 34, characterized in that: The completion notification frame (303) includes information obtained by the shared AP (120) during the execution of the sequential pre-transmission coordination-related process.

36. A method (600) of operating a shared access point (AP) (120), characterized in that: The shared AP (120) is used to participate in coordinated transmission by utilizing at least a portion of a transmission opportunity (TXOP) obtained and shared by a shared AP (110) in a multi-AP (M-AP) set, wherein the method (600) comprises: receiving (601) an M-AP trigger frame (301) from the shared AP (110) operating according to the coordination protocol within the set of M-APs; In response to receiving the M-AP trigger frame (301), initiating (603) a sequential pre-transmission coordination-related process to one or more non-AP stations associated with the shared AP (120) and / or to one or more OBSS non-AP stations associated with one or more other shared APs (120') within the M-AP set; and A completion notification frame (303) is sent (605) to the shared AP (110), wherein the completion notification frame indicates that the sequential pre-transmission coordination-related process is completed.

37. A computer program product, characterized in that The computer program product comprises a computer-readable storage medium for storing program code, which, when executed by a computer or a processor, causes the computer or the processor to perform the method (500) according to claim 21 or the method (600) according to claim 36.

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