A method and apparatus for coordinated multi-access point transmission in wireless communication

Abstract

Techniques related to coordinated multi-access point transmissions in wireless communications are described. A first access point (AP) can perform a frame exchange with a second AP that is applicable to a coordinated transmission. The coordinated transmission can include at least one of coordinated beamforming (CoBF) and coordinated spatial reuse (CoSR). The first AP can transmit a physical layer protocol data unit (PPDU) based on the frame exchange. The frame exchange can include an invitation frame transmitted by the first AP to invite the second AP to participate in the coordinated transmission, a response frame received by the first AP from the second AP in response to the invitation frame to indicate participation in the coordinated transmission, and a trigger frame transmitted by the first AP to the second AP prior to transmitting the PPDU. The trigger frame can include determined information to perform the coordinated transmission.

Description

[Technical Field] This invention generally relates to wireless communication, and more specifically, to coordinated multiple access point transmission in wireless communication. [Background Technology] Unless otherwise stated herein, the methods described in this section are not prior art to the following claims and are not considered prior art by virtue of their inclusion in this section.

[0001] In wireless communications conforming to IEEE standards, such as IEEE 802.11bn, coordinated transmission between multiple access points (APs) is considered a crucial mechanism for improving system performance. Such coordination may involve multiple transmission modes and requires signaling and control procedures before data transmission. In some coordination scenarios, different transmission modes may rely on different signaling mechanisms or procedures, increasing system complexity and signaling overhead. Therefore, technologies supporting coordinated multi-access point transmission are urgently needed to reduce signaling complexity. Furthermore, maintaining consistent transmission behavior when participating sites dynamically become unavailable remains challenging. [Summary of the Invention] The following content aims to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. Some embodiments will be further described in the detailed description below. Therefore, the following content is not intended to identify the essential characteristics of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter.

[0002] In one aspect, a method may include a first access point (AP) and a second AP performing frame exchange suitable for coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial reuse (CoSR) transmission. The method may further include the first AP transmitting a physical layer protocol data unit (PPDU) based on the frame exchange, wherein the frame exchange includes an invitation frame sent by the first AP to invite the second AP to participate in the coordinated transmission, a response frame received by the first AP from the second AP in response to the invitation frame, indicating participation in the coordinated transmission, and a trigger frame sent by the first AP to the second AP prior to transmitting the PPDU, wherein the trigger frame includes determined information for performing the coordinated transmission.

[0003] In another aspect, a device that can be implemented in a first AP may include a transceiver configured for wireless communication and a processor connected to the transceiver. The processor may perform frame exchanges with another AP via the transceiver for coordinated transmissions, wherein the coordinated transmissions include at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission. The processor may also transmit PPDUs based on the frame exchanges via the transceiver, wherein the frame exchanges include an invitation frame sent by the device to invite the other AP to participate in the coordinated transmission, a response frame received by the device from the other AP in response to the invitation frame, indicating participation in the coordinated transmission, and a trigger frame sent by the device to the other AP prior to transmitting the PPDU, wherein the trigger frame includes determined information for performing the coordinated transmission.

[0004] In another aspect, a method may include a frame exchange performed by a second AP and a first AP for a coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission. The method may further include the second AP transmitting a physical layer protocol data unit (PPDU) based on the frame exchange, wherein the frame exchange includes an invitation frame received by the second AP from the first AP to invite the second AP to participate in the coordinated transmission, a response frame sent by the second AP to the first AP in response to the invitation frame to indicate participation in the coordinated transmission, and a trigger frame received by the second AP from the first AP prior to transmitting the PPDU, wherein the trigger frame includes determined information for performing the coordinated transmission.

[0005] It is worth noting that although the description provided herein may be in the context of certain radio access technologies, networks, and network topologies (e.g., Wi-Fi), the proposed concepts, schemes, and any variations / derivatives can be implemented in other types of radio access technologies, networks, and network topologies, for use with, and implemented by, other types of radio access technologies, networks, and network topologies, such as, but not limited to, Bluetooth, ZigBee, 5th Generation (5G) / New Radio (NR), Long-Term Evolution (LTE), LTE-Advanced, LTE-Advanced Pro, Internet of Things (IoT), Industrial Internet of Things (IIoT), and Narrowband Internet of Things (NB-IoT). Therefore, the scope of the invention is not limited to the examples described herein. [Attached Image Description] The accompanying drawings are intended to help readers further understand the content of this invention and constitute a part of the content of this invention. The drawings illustrate embodiments of the invention and, together with the description, are used to explain the concept of the invention. It should be noted that the drawings are not drawn to scale, and the dimensions of some parts may not be proportional to the actual embodiments, in order to clearly illustrate the concept of the invention.

[0006] Figure 1 This is a schematic diagram of an example network environment for implementing various proposed solutions to the present invention.

[0007] Figure 2 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0008] Figure 3 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0009] Figure 4 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0010] Figure 5 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0011] Figure 6 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0012] Figure 7 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0013] Figure 8 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0014] Figure 9 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0015] Figure 10 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0016] Figure 11 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0017] Figure 12 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0018] Figure 13 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0019] Figure 14 This is a schematic diagram of an example scenario under the proposed solution according to the present invention.

[0020] Figure 15This is a block diagram of an example communication system according to an embodiment of the present invention.

[0021] Figure 16 This is an example flowchart according to an embodiment of the present invention.

[0022] Figure 17 This is an example flowchart according to an embodiment of the present invention.

Detailed Implementation Methods

[0023] Overview According to embodiments of the present invention, various techniques, methods, schemes, and / or solutions related to coordinated multi-access point transmission in wireless communication are involved. According to the present invention, a general frame switching architecture suitable for coordinated beamforming (CoBF) and coordinated spatial reuse (CoSR) can be implemented by one or more access points (APs) to support coordinated transmission. In the various embodiments proposed, this general frame switching architecture may include multiple control frames to establish coordination before data transmission and can be used to maintain user consistency between control signaling and physical layer transmission. Although the techniques described herein may be presented separately for clarity, two or more techniques may be implemented individually or in combination to support CoBF or CoSR transmission while adapting to situations where one or more sites are unavailable, thereby improving the robustness of coordination and transmission efficiency.

[0024] Figure 1 An example network environment 100 is shown, illustrating various solutions and schemes for implementing the content of this invention. Figures 2 to 17 Examples of implementing the proposed schemes in network environment 100 are shown. The following references... Figures 1 to 17 Describe the various proposed solutions.

[0025] See Figure 1The network environment 100 may involve at least two AP devices, including a first AP 110 and a second AP 120 for coordinating multi-access point transmission. In some embodiments, the first AP 110 may act as a coordinating access point, also known as a sharing AP device, and the second AP 120 may act as a coordinated access point, also known as a shared AP device. The first AP 110 and the second AP 120 may be deployed in overlapping or adjacent basic service sets (BSS), conforming to one or more Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, such as IEEE 802.11bn, Wi-Fi 8, and future standards, and may work in coordination to perform coordinated transmission for one or more non-AP STAs. It is worth noting that although the various proposed schemes may be described separately or individually below, in actual implementation, each proposed scheme may be used individually or separately, or some or all of the technical schemes may be used in combination.

[0026] See Figure 1 In some embodiments, a first AP 110 (such as a coordinating AP) may initiate a coordinated transport procedure by executing a generic frame switching architecture applicable to CoBF and CoSR. This generic frame switching architecture may include an invitation frame 141 sent by the first AP 110 to a second AP 120 (such as the coordinated AP), whereby the invitation frame 141 requests the second AP 120 to participate in the coordinated transport procedure. Upon receiving the invitation frame 141, the second AP 120 may send a response frame 142 to indicate participation in the coordinated transport procedure. This generic frame switching architecture may also include a synchronization frame 143 (also called a trigger frame) sent before a physical layer protocol data unit (PPDU) so that the exchanged coordination-related information is used to establish consistent transport behavior for subsequent CoBF PPDUs or CoSR PPDUs. In some embodiments, the invitation frame 141 may contain coordinated transport information, which may include CoBF information or CoSR information. In some embodiments, the invitation frame 141 may also indicate whether there is an initial control frame (ICF) / initial control response (ICR) between the shared AP and one or more non-APs associated with the shared AP.

[0027] Upon receiving response frame 142, the first AP 110 may perform intermediate coordination frame exchange with one or more non-AP STAs 131-1 to 131-N for CoBF and CoSR. The second AP 120 may cooperate with the first AP 110 to perform coordinated transmissions, such as jointly sending CoBF transmission 144 or CoSR transmission 144 to one or more non-AP STAs 132-1 to 132-N. Based on the general frame switching architecture, the first AP 110 may send a PPDU for the coordinated transmission. In some embodiments, one or more non-AP STAs may be indicated as targets in the synchronization frame 143 (trigger frame) and the PPDU preamble for the coordinated transmission. If, among one or more non-AP STAs, a non-AP STA is determined to be unavailable (e.g., failing to respond to the ICF during an intermediate coordination frame exchange between the response frame and the synchronization frame (trigger frame), the first AP 110 may retain the unavailable non-AP STA as the target in the physical layer preamble signaling of the synchronization signaling and / or PPDU, while omitting the data portion of the PPDU corresponding to the unavailable non-AP STA. The CoBF-sharing AP and / or the shared AP may not transmit the spatial stream corresponding to the portion of the PPDU corresponding to the unavailable non-AP STA, whereby the portion includes the Ultra-High Reliability Short Training Field (UHR-STF), the Ultra-High Reliability Long Training Field (UHR-LTF), the data field, and padding (if any). The untransmitted portion can be achieved by having nulled energy or zero energy on the spatial stream. The second AP 120 can cooperate with the first AP 110 to support coordinated transmissions, such as participating in the Common Frame Switching Architecture and facilitating CoBF transmission 144 or CoSR transmission 144.

[0028] If a non-AP STA is determined to be unavailable, the non-AP STA can determine that the data portion corresponding to that non-AP STA in the PPDU has been omitted, while the non-AP STA is still the target indicated in the synchronization frame (trigger frame) and the PPDU preamble. Therefore, the non-AP STA can receive signaling associated with CoBF or CoSR, but will not receive the data portion of the PPDU corresponding to that non-AP STA.

[0029] In some embodiments, CoBF and CoSR can be implemented according to the IEEE 802.11bn standard. To trigger the transmission of a Physical Layer Protocol Data Unit (PPDU) for CoBF or CoSR, the shared AP can send a control frame, such as a trigger frame or a multi-station block acknowledgment (multi-STA BA), to configure the shared AP to use the downlink PPDU for coordinated transmission. In some embodiments, the trigger frame or multi-STA BA may include one or more of the following: CoBF or CoSR transmission indication, trigger-based acknowledgment (TB ACK) related information, spatial flow configuration information, BSS color indication, and trigger frame structure information. According to some embodiments of the present invention, a general frame switching architecture suitable for CoBF and CoSR is proposed. In various embodiments, the general frame switching can be implemented using optional scheme 1 (hereinafter referred to as Scheme 1) or optional scheme 2 (hereinafter referred to as Scheme 2). In Scheme 1, the general frame switching is performed sequentially. In Scheme 2, the general frame switching is performed using a trigger-based (TB) mechanism. In some embodiments, in Schemes 1 and 2, an indication of the CoBF / CoSR response location can be provided to indicate the carrying position of the CoBF / CoSR response information in frame switching. Furthermore, based on a general frame switching architecture, some embodiments propose carrying coordination-related information in the CoBF / CoSR invitation and response frames. Two alternative signaling methods can be supported to trigger CoBF / CoSR transmission. In Option 1, the required user information is carried in a user information field, and the design of the user information field is similar to the user information field in the IEEE 802.11be trigger frame structure. In Option 2, a special user information field is used to carry the user information of the CoBF or CoSR PPDU, and the first AID in the special user information field is not the STA AID. These methods can be implemented individually or in combination to support coordinated multi-access point transmission.

[0030] It should be noted that the general frame switching architecture in this application is a process applicable to both CoBF and CoSR, and "general" here does not refer to an existing architecture.

[0031] Figure 2An example scenario 200 of the coordinated multi-access point (CAPT) transmission process according to the present invention is illustrated. In this example, Scheme 1 is shown as a general frame switching architecture suitable for Coordinated Beamforming (CoBF) and Coordinated Spatial Multiplexing (CoSR). Under Scheme 1, the sharing access point AP1 and the shared access point AP2 exchange a set of frames, including invitation frames, response frames, and synchronization (trigger) frames, to support a unified transmission process for CoBF and CoSR, thereby simplifying standard design. In some embodiments of Scheme 1, invitation and response frames are exchanged between AP1 and AP2 for exchanging information for performing CoBF or CoSR physical layer protocol data unit (PPDU) transmissions, such as participation in coordinated transmissions and user-related information. Optionally, intermediate coordination frames (ICF / ICR) may be sent, for example, to check the availability of one or more non-access point (STA) units and prepare one or more STA units for reception, wherein the inclusion of intermediate coordination frames (ICF / ICR) is optional and is explicitly indicated in the invitation frame. After exchanging invitation and response frames, AP1 sends a synchronization frame (trigger frame), which serves as a CoBF / CoSR synchronization frame (or trigger frame) under Scheme 1. The synchronization frame (trigger frame) may carry determined information necessary for executing a CoBF or CoSR PPDU transmission, enabling subsequent PPDU transmissions by AP1 and AP2 to be executed synchronously. Following the synchronization frame (trigger frame), AP1 and AP2 send one or more CoBF or CoSR PPDUs to multiple non-access point STAs (e.g., non-access point STA1 and non-access point STA2). In some embodiments, if a non-access point STA associated with AP1 receives an ICF but does not send an ICR to AP1, AP1 determines that the non-access point STA is unavailable; similarly, if a non-access point STA associated with AP2 receives an ICF but does not send an ICR to AP2, AP2 determines that the non-access point STA is unavailable. In some embodiments, even if a non-access point (STA) is determined to be unavailable, the unavailable STA may still be retained as a target in the preamble of the synchronization frame (trigger frame) and / or PPDU, while the data portion of the PPDU corresponding to the unavailable STA is omitted. After AP1 and AP2 send one or more CoBF or CoSR PPDUs, AP1 can receive a trigger-based acknowledgment (TB PPDU). The trigger-based acknowledgment can be an ACK or a block ACK. Figure 2In this example, it is assumed that non-access point STA1 is associated with AP1, and non-access point STA2 is associated with AP2. Regarding the acknowledgment signaling under Scheme 1, two alternative schemes are shown. Under Scheme 1-1, multiple non-access point STAs send trigger-based acknowledgments in response to CoBF or CoSR PPDU transmissions. Specifically, in Scheme 1-1, the non-access point STA associated with AP1 and the non-access point STA associated with AP2 send TB ACKs in response to coordinated CoBF / CoSR PPDU transmissions. Each TB ACK corresponds to the corresponding non-access point STA participating in the coordinated transmission, thereby allowing the sharing access point (AP1) and the shared access point (AP2) to independently determine their reception status. Under Scheme 1-2, acknowledgments are transmitted sequentially in block acknowledgments (BA) according to BSS. Depending on the specific implementation, either Scheme 1-1 or Scheme 1-2 can be selected. Therefore, by adopting the general frame switching architecture of Scheme 1 and the general CoBF / CoSR synchronization frame (trigger frame), and supporting the acknowledgment signaling under Scheme 1-1 or Scheme 1-2, the proposed scheme can provide efficient, flexible and reliable coordinated multi-access point transmission for CoBF and CoSR.

[0032] Figure 3An example scenario 300 of the CoBF and CoSR universal frame switching architecture according to Scheme 1 of the present invention is illustrated. Example scenario 300 further illustrates different positions where CoBF response information is carried in response to a CoBF invitation frame. In some embodiments, it has a technical advantage to carry the CoBF response information in the first response frame sent after receiving the CoBF invitation frame. In this case, the sharing access point can obtain the CoBF response information earlier, thus having more time to calculate the precoding matrix for subsequent CoBF PPDU transmissions. However, in some embodiments, it may be difficult to fully feed back CoBF-related parameters, such as the information required for calculating the precoder for subsequent CoBF PPDU transmissions, in the first response frame sent after receiving the CoBF invitation frame. To accommodate both situations, some embodiments of the present invention propose a flexible mechanism under Scheme 1. Specifically, in example scenario 300, the shared access point carries a response position indication in the first response frame (such as the first ICR sent after receiving the invitation frame). The response position indication is configured to indicate the position of the CoBF response information. When the response location indicator is set to a first value (e.g., 1), the CoBF response information is not carried in the first response frame, but rather in a subsequent intermediate coordination frame (e.g., ICF). When the response location indicator is set to a second value (e.g., 0), the CoBF response information is carried in the first response frame, such as the first ICR. Therefore, by introducing the response location indicator in the first response frame under Scheme 1, the proposed scheme provides implementation flexibility to support different processing capabilities of access points while maintaining a unified and common frame switching architecture for CoBF and CoSR.

[0033] Figure 4 The information carried in the CoBF invitation frame and CoBF response frame according to Scheme 1 of the present invention is shown. For example... Figure 4As shown, the CoBF invitation frame and CoBF response frame are configured to carry information needed to compute the precoder (e.g., compute the precoding matrix) for subsequent CoBF PPDU transmissions. In some embodiments, the CoBF invitation frame carries signaling information related to the coordinated transmission, including indications of CoBF or CoSR operations, transmission opportunity (TXOP) related parameters, bandwidth information, and user-specific parameters. The CoBF response frame sent by the shared access point may carry corresponding response information to confirm participation in the coordinated transmission and provide information needed for precoder computation. Furthermore, in example scenario 400, some embodiments of the invention propose that the CoBF invitation frame further carry a request for additional ultra-high reliability long training field (UHR-LTF) symbols. The request for additional UHR-LTF symbols can improve channel estimation and reception performance for subsequent CoBF PPDU transmissions, especially in scenarios involving coordinated transmissions from multiple access points. Some embodiments of the invention also propose that the CoBF invitation frame carry an indication of whether to send an intermediate coordination frame (ICF / ICR). When the indication is set to a first value (e.g., 1), the shared access point determines that an ICF needs to be sent to prepare one or more non-access points (STAs) associated with that shared access point for reception. When an ICF needs to be sent, it is sent between response frame 142 and synchronization frame 143 (trigger frame). When the indication is set to a second value (e.g., 0), the shared access point skips the transmission of ICF / ICR within its basic service set (BSS), thereby reducing signaling overhead. Therefore, in Scheme 1, the CoBF invitation frame and the CoBF response frame together provide a self-contained coordination transport signaling mechanism, which helps to achieve efficient precoder calculation and flexible coordination behavior, while maintaining a general frame switching architecture applicable to both CoBF and CoSR.

[0034] Figure 5Example scenario 500 under scheme 2 is illustrated, which provides a common frame switching architecture for Coordinated Beamforming (CoBF) and Coordinated Spatial Multiplexing (CoSR) transmissions. Compared to scheme 1, scheme 2 aims to reduce frame switching overhead and airtime consumption by utilizing trigger-based physical layer protocol data units (TB PPDUs). In example scenario 500, a CoBF / CoSR invitation frame sent by the shared AP simultaneously requests responses from the shared AP and one or more associated non-AP STAs. The ICR associated with the shared AP and the ICR associated with one or more associated non-AP STAs can be sent via TB PPDUs, where the ICR associated with the shared AP can carry a CoBF / CoSR response frame. By sending the ICR associated with the shared AP and the ICR associated with one or more associated non-AP STAs via TB PPDUs, the multiple frame switching required in scheme 1 can be eliminated, thereby reducing airtime consumption by approximately five frame switching in some implementations. Furthermore, since the CoBF invitation frame sent by the sharing AP simultaneously requests responses from the shared AP and one or more associated non-AP STAs, even if the shared AP refuses to participate in CoBF or CoSR transmission, the sharing AP can still obtain TXOPs and continue downlink transmission to its associated non-AP STAs after receiving responses from one or more associated non-AP STAs. This mechanism improves transmission robustness and avoids wasting TXOPs in coordinated transmission scenarios. Scheme 2 may require the coordinated beamforming access point to support TB PPDU transmission. During access point negotiation or pairing, the sharing AP and the shared AP can exchange capability information to indicate whether TB PPDU transmission is supported. Based on the exchanged capability information, the shared AP's ICR participation can be optional, and the sharing AP and the shared AP can further negotiate to fall back to the frame switching architecture of Scheme 1 when TB PPDU transmission is not supported. Therefore, Scheme 2 provides a flexible and efficient general frame switching architecture for CoBF and CoSR transmission, while maintaining backward compatibility through capability negotiation and optional fallback to Scheme 1. Furthermore, in Figure 5 In the example scenario 500 shown, ICRs sent by the shared AP and associated non-AP STAs can be flexibly supported, either as separate coordination frames or as information transmitted via TB PPDUs. These ICRs can be optional and can be indicated during AP pairing or grouping. By allowing the aggregation, omission, or conditional transmission of ICRs from different participating entities, the proposed scheme 2 provides a unified and efficient coordination mechanism, reducing signaling overhead while maintaining reliable and consistent CoBF / CoSR transmission behavior.

[0035] See Figure 6Example scenario 600 illustrates a continuation of the general frame switching architecture for CoBF and CoSR under scheme 2. Similar to scheme 1, scheme 2 also supports carrying an indication of the CoBF response location in the first response frame sent after the shared AP receives the invitation frame, for example, in the first ICR sent after the shared AP receives the invitation frame. In some embodiments, the indication carried in the first response frame (e.g., the first ICR after receiving the invitation frame) indicates whether the CoBF response information is included in that first response frame or deferred to a subsequent intermediate coordination frame (e.g., ICF). When the indication is set to a first value (e.g., set to 1), the CoBF response information is not included in the first response frame (e.g., the first ICR after the invitation frame), and an additional ICF is required to convey the CoBF response information. When the indication is set to a second value (e.g., set to 0), the CoBF response information is directly included in the first response frame (e.g., the first ICR). By supporting the CoBF response location indication in scheme 2, the proposed scheme provides implementation flexibility. Therefore, the coordinated transmission process under Scheme 2 can adapt to the different processing capabilities of the participating access points, while maintaining a unified and universal frame switching architecture for CoBF and CoSR transmissions.

[0036] See Figure 7Example scenario 700 illustrates the information carried in the CoBF invitation frame and CoBF response frame under scheme 2. Similar to scheme 1, the CoBF invitation frame and CoBF response frame in scheme 2 are configured to carry information required for calculating the CoBF or CoSR transport precoding matrix. In some embodiments, the information carried in the CoBF invitation frame may include an invitation subfield for inviting the shared AP to participate in CoBF or CoSR transport. The information carried in the CoBF invitation frame may also include an indication of the coordinated transport type (such as CoBF or CoSR). The information carried in the CoBF invitation frame may also include one or more pieces of information, such as bandwidth information, TXOP information, modulation and coding scheme (MCS) information, and site identifier (STA ID) information for one or more participating non-AP STAs, wherein the one or more participating non-AP STAs are associated with the shared AP and are scheduled by the shared AP to participate in CoBF transport. In some embodiments, the information carried in the CoBF response frame may include a subfield indicating whether to participate in CoBF transmission, and site identifier (STA ID) information for one or more participating non-AP STAs, wherein the one or more participating non-AP STAs are associated with the shared AP and are scheduled to participate in CoBF transmission by the shared AP. Furthermore, the CoBF invitation frame may include an indication requesting additional UHR-LTF symbols, and the CoBF response frame may include a corresponding indication indicating whether the requested additional UHR-LTF symbols are allowed. By carrying such precoder-related information directly in the CoBF invitation and CoBF response frames under Scheme 2, the proposed scheme enables the sharing AP and the shared AP to exchange necessary transmission parameters without introducing additional frame switching, thereby supporting efficient precoder calculation while maintaining reduced signaling overhead from trigger-based transmissions.

[0037] See Figure 8Example scenario 800 illustrates information carried in a trigger frame or synchronization frame used to trigger CoBF or CoSR PPDU transmission. In some embodiments, the trigger frame is configured to provide determined and self-contained transmission information for subsequent CoBF or CoSR PPDU transmissions. In some embodiments, the trigger frame may include one or more fields indicating the coordinated transmission type (such as CoBF or CoSR), as well as bandwidth, TXOP, puncturing channel information, and basic service set (BSS) color information. The trigger frame may also carry signaling associated with UHR-SIG, including the modulation and coding scheme (MCS), the number of UHR-SIG symbols, and the number of UHR-LTF symbols. Some information (such as the number of UHR-SIG symbols and the number of UHR-LTF symbols) may be carried in a common signaling field to ensure that all participating APs (or all participating APs and non-AP STAs) can interpret the transmission parameters consistently. In some embodiments, the trigger frame may also include multiple user information fields to provide corresponding user information for multiple CoBF users. For each user, user information may include STA ID, MCS, spatial configuration information, BSS flag, and a two-times low-density parity-check (2×LDPC) indication. The user order in the trigger frame can correspond to the user order used in subsequent CoBF or CoSR PPDUs, thereby achieving a consistent user mapping between signaling in the trigger frame and CoBF or CoSR PPDU transmissions. Specifically, the user order in the trigger frame is consistent with the user order in the UHR-SIG user field of the CoBF or CoSR PPDU. In addition, when the TB acknowledgment mechanism is applied, the trigger frame may also include TB-related information, such as BA type, number of trigger-based block acknowledgment (TBBA) data symbols, PS160 indication of the TBBA, and resource unit (RU) allocation information allocated to the shared AP. By aggregating such triggering and synchronization information into a single trigger frame, the proposed scheme achieves efficient and reliable CoBF or CoSR PPDU transmission triggering, while reducing signaling overhead and ensuring coordinated transmission behavior among multiple APs and their associated non-AP STAs. The CoBF or CoSR PPDU may include the L-SIG, U-SIG, UHR-SIG common fields, and the UHR-SIG user field.

[0038] See Figure 9Example Scenario 900 illustrates Example 1, where a Buffer Status Report Poll (BSRP) based control frame is used as a trigger frame for Coordinated Beamforming (CoBF) or Coordinated Spatial Reuse (CoSR) transmission. In this example, the BSRP-based control frame is extended or modified to carry the information required to trigger the CoBF or CoSR Physical Layer Protocol Data Unit (PPDU). In some embodiments, when the BSRP is used as a CoBF or CoSR trigger frame, the required signaling information may be carried in one or more common information fields, special user information fields, and user information fields corresponding to the shared access point (AP). Such information may include, for example, indications of CoBF or CoSR operation, bandwidth and TXOP-related parameters, punctured channel information, spatial reuse configuration, UHR-SIG parameters, and transmit power control information of the shared AP. Compared to existing trigger frame formats, such as Figure 9 As shown, some fields can be reused or extended to support coordinated multi-access point transmission. In some embodiments, special user information fields may carry AP-specific information, such as the shared AP identifier, trigger-based (TB) acknowledgment configuration, resource element (RU) allocation for the shared AP, and TB-related parameters. Furthermore, multiple user information fields are included. Each user information field may carry site information, including a site identifier, RU allocation, forward error correction (FEC) indication, modulation and coding scheme (MCS), spatial stream allocation, and 2×LDPC indication. According to some embodiments of the present invention, the site ordering in subsequent CoBF or CoSR PPDUs triggered by a BSRP-based control frame may adopt the same site ordering as in the trigger frame. By maintaining consistent ordering between the trigger frame and the CoBF or CoSR PPDU, coordinated transmission behavior between multiple APs and their associated non-AP STAs can be ensured, thereby improving coordination efficiency and reducing signaling ambiguity.

[0039] See Figure 10 Example scenario 1000 illustrates example 2, which is... Figure 9The variant of the BSRP-based CoBF or CoSR control frame. This variant of the BSRP-based CoBF or CoSR control frame includes multiple user information fields. In this example, the signaling quantity can be further reduced when the AP is able to memorize the site identifiers (STAIDs) of the associated non-AP STAs involved in the coordinated transmission. In some embodiments, the user information fields in the BSRP-based control frame can be further simplified when the AP memorizes the STAIDs. Instead of carrying a separate user information entry for each non-AP STA, information for multiple non-AP STAs can be aggregated and carried in a single user information field. For example, information corresponding to four non-AP STAs, such as MCS, 2×LDPC indication, and Basic Service Set (BSS) flag, can be carried together in a single user information entry. In some embodiments, the shared AP can explicitly indicate the STAIDs in a non-increasing order of the number of spatial flows allocated to each site in the spatial configuration. In some embodiments, the user information field carrying one or more non-AP STA information can be associated with a special AID that is not a traditional site AID. This special AID can be known in advance by the shared AP, thereby allowing the shared AP to correctly interpret the user information, wherein the special AID is the AID located at the beginning of the user information field. According to some embodiments of the present invention, Figure 10 Two example formats for the user information field are shown. By using a special AID and user information, signaling overhead in BSRP-based control frames can be further reduced while maintaining information consistency between the control frame and subsequent CoBF or CoSR PPDU. Therefore, coordinated multi-access point transmission efficiency can be improved without compromising site configuration flexibility.

[0040] See Figure 11Example scenario 1100 illustrates a frame switching procedure for CoBF / CoSR, where an Initial Control Frame (ICF) and / or an Initial Control Response (ICR) are sent during the general frame switching process. Invitation / response frames may carry indications to indicate whether an Intermediate Coordination Frame (ICF / ICR) is available. In some embodiments, the ICF (sent by the shared AP) / ICR frame is used to check the availability of a non-AP STA associated with the shared AP and prepare that non-AP STA for reception prior to CoBF or CoSR PPDU transmission. The ICF (sent by the shared AP) / ICR frame is used to check the availability of a non-AP STA associated with the shared AP and prepare that non-AP STA for reception prior to CoBF or CoSR PPDU transmission. The non-AP STA may be an enhanced multi-link single-radio (EMLSR) site or a dynamically unavailable operation (DUO) site. In some embodiments, after exchanging CoBF or CoSR invitation and response frames between the sharing AP and the shared AP, one or more ICF or ICR frames may be selectively sent based on the indications of the invitation and / or response frames. The ICF frame may request a response from the associated non-AP STA to determine whether these non-AP STAs are available for subsequent coordinated transmissions. Several processing options are supported when a non-AP STA associated with the sharing AP does not respond to the ICF. Option 1: The sharing AP retains the unavailable non-AP STA in the preamble of the synchronization frame (trigger frame) and the CoBF or CoSR PPDU, while omitting the data portion of the corresponding unavailable non-AP STA in the CoBF or CoSR PPDU. Option 2: The sharing AP removes the unavailable non-AP STA from the synchronization frame (trigger frame), so that the unavailable non-AP STA is no longer indicated as the target of subsequent CoBF or CoSR PPDUs. Option 3: The sharing AP applies additional indications to explicitly mark the non-AP STA as unavailable. In some embodiments, Option 3 provides an additional technical advantage: when sufficient processing time is available (e.g., through padding or delayed transmission), the shared AP can recalculate the precoding matrix based on the updated set of available non-AP STAs. Therefore, coordinated transmission performance and robustness can be improved during public frame switching, while maintaining flexibility in handling dynamic site availability.

[0041] See Figure 12Example scenario 1200 illustrates an embodiment corresponding to option 1, where unavailable non-AP STAs are preserved in the preamble of the synchronization frame (trigger frame) and the CoBF or CoSR PPDU. In this example, the sharing AP and the shared AP exchange site lists via CoBF invitation and response frames, respectively. In some embodiments, each of the CoBF invitation and response frames carries only site information associated with the sending AP. Figure 12 As shown, the sharing AP initially indicates a first group of associated sites (e.g., STA1 and STA2) in the invitation frame, while the shared AP indicates a second group of associated sites (e.g., STA3 and STA4) in the response frame. The first group of associated sites (e.g., STA1 and STA2) is associated with the sharing AP, and the second group of associated sites (e.g., STA3 and STA4) is associated with the shared AP. Subsequently, one or more intermediate coordination frames (e.g., ICF1 and ICF2) and corresponding responses (e.g., ICR1 and ICR2) are exchanged to check the availability of the associated sites. In some embodiments, when a non-AP STA (e.g., STA2) associated with the sharing AP does not respond to an intermediate coordination frame (e.g., ICF1), the sharing AP can infer that the channel conditions associated with that non-AP STA are poor, such as due to a busy channel or overlapping basic service set (OBSS) interference. In this case, multiple implementation options can be supported. For example, a sharing AP might decide to continue sending data to a non-AP STA even if it doesn't respond; alternatively, it might retain the non-AP STA in the synchronization frame (trigger frame) and PPDU preamble, omitting the data portion corresponding to the unavailable non-AP STA. In some cases, the non-AP STA may still be listed as a transmission target for synchronization and signaling purposes (e.g., included in the PPDU preamble), but no data will be sent to the unavailable non-AP STA. In this case, the scheduling of the non-AP STA remains consistent with the invitation and response frames, allowing the sharing AP and the shared AP to begin CoBF precoder processing early, as the number of sites and spatial stream configuration in the synchronization frame (trigger frame) do not change dynamically. The site list carried in the synchronization frame (trigger frame) must be consistent with that in the PPDU for preamble content alignment between the sharing AP and the shared AP. For unavailable non-AP STAs, the AP associated with the unavailable non-AP STA can allocate empty or zero energy on the unavailable non-AP STA's spatial stream to further reduce interference to participating sites. For example, an AP associated with an unavailable non-AP STA allocates empty or zero energy on the spatial flow of the PPDU portion corresponding to the unavailable non-AP STA, where the portion includes UHR-STF, UHR-LTF, data fields, and padding (if any).

[0042] See Figure 13Example scenario 1300 illustrates an embodiment corresponding to option 2, where unavailable non-AP STAs are removed from the synchronization frame and the preamble of the CoBF or CoSR PPDU. Similar to... Figure 12 In the example scenario shown, the sharing AP and the shared AP exchange lists of their associated STAs via CoBF invitation and response frames, respectively, and intermediate coordination frames (e.g., ICF1 and ICF2) are sent to check the availability of associated non-AP STAs. ICF1 is sent by the sharing AP to one or more non-AP STAs (e.g., STA1 and STA2). ICR1 is sent by STA1 in response to ICF1. ICF2 is sent by the shared AP to one or more non-AP STAs (e.g., STA3 and STA4). ICR2 is sent by STA3 and STA4 in response to ICF2. Figure 13 As shown, when a non-AP STA (e.g., STA2) does not respond to an intermediate coordination frame (such as ICF1), the shared AP can determine that the non-AP STA is unavailable in the upcoming coordination transmission. According to Option 2, the shared AP can remove the unavailable non-AP STA from subsequent coordination signaling, including removing it from the preamble of the synchronization frame and the CoBF or CoSR PPDU. In this embodiment, only the remaining available non-AP STAs (e.g., STA1, STA3, and STA4) are indicated as transmission targets in the synchronization frame and PPDU preamble, and only these available non-AP STAs carry the corresponding user information. By excluding unavailable non-AP STAs from the synchronization frame and PPDU preamble, signaling overhead in the UHR-SIG user field can be reduced, thereby saving airtime and improving transmission efficiency. Therefore, Option 2 enables the shared AP and the shared AP to dynamically update the target non-AP STA set based on availability feedback, adapting to the coordination transmission process while maintaining consistency between general frame switching and the final CoBF or CoSR PPDU transmission.

[0043] See Figure 14 Example scenario 1400 illustrates an embodiment corresponding to option 3, where additional indications are provided for unavailable non-AP STAs during the coordinated multi-access point transport process. Similar to... Figure 12 and Figure 13 In the example scenario shown, the sharing AP and the shared AP exchange information about their associated non-AP STAs via CoBF invitation and response frames, and intermediate coordination frames (e.g., ICF1 and ICF2) are sent to check the availability of the associated non-AP STAs. Figure 14As shown, when a non-AP STA (e.g., STA2) does not respond to the intermediate coordination frame (e.g., ICF1), the sharing AP can determine that the non-AP STA is unavailable. According to option 3, instead of directly removing the unavailable non-AP STA from the preamble of the synchronization frame and CoBF or CoSR PPDU, the sharing AP provides an explicit indication of the unavailable non-AP STA to the shared AP. In some embodiments, this explicit indication can be achieved by replacing the identifier of the unavailable non-AP STA in the preamble of the synchronization frame and / or CoBF or CoSR PPDU with a special STAID. By using the special STAID, the sharing AP notifies the shared AP that the corresponding non-AP STA is unavailable, while still maintaining the consistency of the overall user ordering and frame structure. Based on the explicit indication carried by the special STAID, the shared AP can determine that the corresponding non-AP STA is unavailable and can decide whether to reuse the previously calculated precoding matrix or recalculate the precoding matrix, for example, if there is sufficient processing time or additional padding can be applied. Therefore, Option 3 provides enhanced coordination flexibility, enabling the shared AP to make informed decisions regarding precoder computations, thereby improving the robustness and feasibility of coordinated beamforming or coordinated spatial multiplexing.

[0044] Example Implementation Figure 15 An example system 1500 is illustrated, comprising at least one example device 1510 and one example device 1520, according to an embodiment of the present invention. Both device 1510 and device 1520 can perform various functions to implement the schemes, techniques, processes, and methods described herein related to coordinated multiple access point (MAP) transmissions, including CoBF transmissions and CoSR transmissions as described above, as well as various proposed designs, concepts, schemes, systems, and methods. For example, device 1510 can be implemented in a shared AP, and device 1520 can be implemented in a shared AP, or vice versa.

[0045] When implemented as an access point (AP), device 1510 or device 1520 can be implemented in a wireless router, a wireless local area network (WLAN) access point, or a network controller. When device 1520 is implemented as a stand-alone (STA), device 1520 can be implemented in a smartphone, smartwatch, personal digital assistant, digital camera, or computing device such as a tablet, laptop, or mobile phone. Devices 1510 and 1520 can also be part of a machine-type device, which can be an Internet of Things (IoT) device, such as a non-movable or fixed device, a home appliance, a wired communication device, or a computing device. For example, devices 1510 and 1520 can be implemented in a smart thermostat, a smart refrigerator, a smart door lock, a wireless speaker, or a home control center. When implemented in a network device, device 1510 and / or device 1520 can be implemented in a network node, such as an AP in a WLAN.

[0046] In some implementations, devices 1510 and 1520 may be implemented as one or more integrated circuit (IC) chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction-set computing (RISC) processors, or one or more complex-instruction-set computing (CISC) processors. In the various embodiments described herein, devices 1510 and 1520 may be implemented as AP devices participating in coordinating multi-AP transmissions. Devices 1510 and 1520 may each include... Figure 15 The at least some components shown include, for example, processors 1512 and 1522. Devices 1510 and 1520 may also include one or more other components unrelated to the present invention (e.g., internal power supply, display device, and / or user interface device); therefore, for the sake of brevity, Figure 15 These components are not shown and will not be described below.

[0047] In one aspect, processors 1512 and 1522 may be implemented as one or more single-core processors, one or more multi-core processors, one or more RISC processors, or one or more CISC processors. That is, although the singular term "processor" is used herein to refer to processors 1512 and 1522, in some embodiments, processors 1512 and 1522 may be a single processor, and in some embodiments, processors 1512 and 1522 may include multiple processors. In another aspect, processors 1512 and 1522 may be implemented in hardware (and optionally firmware) comprising, for example, but not limited to, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors, and / or one or more transformers, these electronic components being configured and arranged to achieve a specific purpose of the invention. In other words, in at least some embodiments, processors 1512 and 1522 are special-purpose machines specifically designed, arranged, and configured to perform specific tasks, including tasks related to coordinating multi-access point transmissions, such as CoBF and CoSR transmissions in wireless communications, consistent with various embodiments of the invention.

[0048] In some embodiments, device 1510 may further include a transceiver 1516 connected to processor 1512. Transceiver 1516 may include a transmitter capable of wireless transmission and a receiver capable of wirelessly receiving data. In some embodiments, device 1520 may further include a transceiver 1526 connected to processor 1522. Transceiver 1526 may include a transmitter capable of wireless transmission and a receiver capable of wirelessly receiving data. It is worth noting that although transceiver 1516 and transceiver 1526 are shown in the figures as external independent components of processor 1512 and processor 1522, respectively, in some embodiments, transceiver 1516 may be integrated as a system-on-a-chip (SoC) into processor 1512, and transceiver 1526 may also be integrated as a SoC into processor 1522.

[0049] In some embodiments, device 1510 may further include a memory 1514 connected to and accessible by processor 1512 for storing data. In some embodiments, device 1520 may further include a memory 1524 connected to and accessible by processor 1522 for storing data. Each of memory 1514 and memory 1524 may include a random-access memory (RAM), such as dynamic RAM (DRAM), static RAM (SRAM), thyristor RAM (T-RAM), and / or zero-capacitor RAM (Z-RAM). Alternatively, or additionally, each of memory 1514 and memory 1524 may include a read-only memory (ROM), such as a mask ROM, programmable ROM (PROM), erasable programmable ROM (EPROM), and / or electrically erasable programmable ROM (EEPROM). Alternatively, each of the memories 1514 and 1524 may include a non-volatile random access memory (NVRAM), such as flash memory, solid-state memory, ferroelectric RAM (FeRAM), magnetoresistive RAM (MRAM), and / or phase-change memory.

[0050] Each of devices 1510 and 1520 can be a communication entity capable of communicating with each other according to various proposed embodiments of the present invention. For illustrative purposes and without limitation, a description of the capabilities of device 1510 as a first access point (AP) 110 and device 1520 as a second AP 120 is provided below. It is worth noting that although the capabilities, functions, and / or technical features of device 1520 are described in detail below, these can also be applied to device 1510, although they are not described in detail for the sake of brevity. It is also worth noting that although the example embodiments described below are provided in the context of a wireless local area network (WLAN), they can also be implemented in other types of networks.

[0051] According to various proposed embodiments of the present invention, coordinated multiple access point transmission, including coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission, is involved. In wireless communication, device 1510 is implemented as a first access point (AP) 110, and device 1520 is implemented as a second access point (AP) 120. In network environment 100, according to one or more IEEE 802.11 standards, the processor 1512 of device 1510 can perform frame exchange suitable for coordinated transmission with device 1520 via transceiver 1516, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission. Furthermore, the processor 1512 can transmit physical layer protocol data units (PPDUs) based on this frame exchange via transceiver 1516. In some embodiments, the frame exchange includes an invitation frame sent by a first AP to invite a second AP to participate in the coordinated transmission, a response frame received by the first AP from and sent by the second AP to respond to the invitation frame and indicate participation in the coordinated transmission, and a trigger frame sent by the first AP to the second AP before sending a PPDU, wherein the trigger frame includes determined information for performing the coordinated transmission.

[0052] In some implementations, processor 1512 may cause the invitation frame to carry an indication for instructing the first AP whether to send an initial control frame to prepare one or more non-AP STAs associated with the first AP for reception. The initial control frame is used to check the availability of one or more non-AP STAs associated with the first AP. When the first AP needs to send an initial control frame, it is sent between a response frame and a trigger frame.

[0053] In some implementations, the trigger frame includes a user information field configured to carry user information for a PPDU, and the AID field at the beginning of the user information field does not point to the AID field of a non-AP STA associated in the coordinated transmission. In some implementations, the user information field is configured to carry information for one or more non-AP STAs in a user information entry, and each of the one or more non-AP STAs includes at least one of a modulation and coding scheme (MCS), a 2×LDPC indicator, and a Basic Service Set (BSS) flag.

[0054] In some implementations, all non-APSTAs scheduled to participate in the coordinated transmission listed in the invitation and response frames are presented in the preamble of the PPDU in the trigger frame and the coordinated transmission. In some implementations, if a non-AP STA scheduled to participate in the coordinated transmission by the first AP is unavailable, that non-AP STA is retained in the preamble of the trigger frame and the PPDU, while the data portion corresponding to that non-AP STA in the PPDU is omitted. In some implementations, the invitation frame is used to request the second AP and one or more non-AP STAs associated with the first AP to send a trigger-based PPDU, wherein the response frame from the second AP and the ICR from one or more non-AP STAs are carried in the trigger-based PPDU.

[0055] In some implementations, the first response sent by the second AP in response to the invitation frame carries an indication of the location of the response frame carrying Coordinated Beamforming (CoBF) response information. In some implementations, this indication indicates whether the response frame carrying CoBF response information is in the first response or in a subsequent intermediate coordination frame sent by the second AP. In some implementations, a non-AP STA is determined to be unavailable if it does not respond to an initial control frame sent by its associated AP, wherein the initial control frame is used to prepare the non-AP STA for reception. In some implementations, processor 1512 can receive trigger-based acknowledgments sent by one or more STAs associated with the first AP via transceiver 1516. In some implementations, the user order in the trigger frame is consistent with the user order in the UHR-SIG user field of the PPDU used for coordinated transmission.

[0056] Explanatory process Figure 16 An example flow 1600 according to an embodiment of the present invention is shown. Flow 1600 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, flow 1600 may represent one aspect of proposed concepts and schemes for coordinating multi-access point transmissions according to the present invention. Flow 1600 may include one or more operations, actions, or functions as shown in blocks 1610 and 1620. Although shown in discrete block form, the individual blocks of flow 1600 may be divided into more blocks, merged into fewer blocks, or omitted according to the desired implementation. Furthermore, the blocks / sub-blocks of flow 1600 may be arranged according to... Figure 16The process can be executed in the order shown, or in a different order. Furthermore, one or more blocks / sub-blocks of process 1600 can be executed repeatedly or iteratively. Process 1600 can be implemented by device 1510 or device 1520, and any variations thereof. For illustrative purposes only and without limitation, in network environment 100, device 1610 is implemented as the first AP 110, and device 1520 is implemented as the second AP 120, and process 1600 is described below according to one or more IEEE 802.11 standards. Process 1600 may begin with block 1610.

[0057] At 1610, process 1600 may involve processor 1512 performing frame exchange with a second AP via transceiver 1516 for coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission. Process 1900 may proceed from 1910 to 1920.

[0058] At 1620, process 1600 may involve processor 1512 transmitting Physical Layer Protocol Data Units (PPDUs) based on the frame exchange via transceiver 1516, wherein the frame exchange includes an invitation frame sent by a first AP to invite a second AP to participate in a CoBF or CoSR transmission, a response frame received by the first AP from the second AP in response to the invitation frame and indicating participation in the CoBF or CoSR transmission, and a trigger frame sent by the first AP to the second AP before transmitting the PPDU, wherein the trigger frame includes determined information for performing the CoBF or CoSR transmission.

[0059] In some implementations, the invitation frame exchanged in procedure 1600 may carry an indication indicating whether the first AP should send an initial control frame to prepare one or more non-AP STAs associated with the first AP for reception. In some implementations, when an initial control frame needs to be sent, it may be sent between a response frame and a trigger frame.

[0060] In some implementations, the trigger frame includes a user information field configured to carry user information for the physical layer protocol data unit (PPDU), and the AID field at the beginning of the user information field is not an AID field pointing to the associated non-AP STA in the coordinated transport. In some implementations, the user information field is configured to carry one or more non-AP STA information entries, and each of the one or more non-AP STA information entries includes at least one of a modulation and coding scheme (MCS), a two-times low-density parity-check (2×LDPC) indicator, and a basic service set (BSS) flag.

[0061] In some implementations, all non-AP STAs scheduled to participate in the coordinated transmission, listed in the invitation and response frames, are presented in the preamble of the PPDU in the trigger frame and the coordinated transmission. In some implementations, if a non-AP STA scheduled to participate in the coordinated transmission by the first access point (AP) is unavailable, that non-AP STA is retained in the preamble of the trigger frame and the PPDU, while the data portion of the PPDU corresponding to that non-AP STA is omitted. In some implementations, the invitation frame is used to request a second AP and one or more non-AP STAs associated with the first AP to send a trigger-based PPDU, wherein a response frame from the second AP and an ICR from the one or more non-AP STAs are carried in the trigger-based PPDU. In some implementations, a first response sent by the second AP in response to the invitation frame carries an indication of the location of a response frame carrying coordinated beamforming (CoBF) response information. This first response may be the first response sent by the second AP after receiving the invitation frame. In some implementations, the indication is used to indicate whether the response frame carrying CoBF response information is in the first response or in a subsequent intermediate coordination frame sent by the second AP. In some implementations, a non-AP STA is determined to be unavailable when it does not respond to an initial control frame sent by its associated AP, wherein the initial control frame is used to prepare the non-AP STA for reception.

[0062] In some implementations, process 1600 may involve processor 1512 receiving, via transceiver 1516, a trigger-based acknowledgment sent by one or more STAs associated with the first AP. In some implementations, the user order in the trigger frame is consistent with the user order in the UHR-SIG user field of the PPDU used for coordinating transmissions.

[0063] Figure 17 Process 1700 according to an embodiment of the present invention is illustrated by way of example. Process 1700 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, process 1700 may represent one aspect of a proposed concept and scheme for coordinating multiple access point transmissions in wireless communication related to the present invention. Process 1700 may include one or more operations, actions, or functions as shown in blocks 1710 and 1720. Although shown in discrete block form, the blocks of process 1700 may be divided into more blocks, merged into fewer blocks, or omitted depending on the desired implementation. Furthermore, the blocks / sub-blocks of process 1700 may be arranged according to... Figure 17 The process can be executed in the order shown, or in a different order. Furthermore, one or more blocks / sub-blocks of process 1700 can be executed repeatedly or iteratively. Process 1700 can be implemented by device 1520 and any variant thereof. For illustrative purposes only and without limitation, process 1700 is described below in the context of device 1520, which can be implemented in a second AP 120 in network environment 100 according to one or more IEEE 802.11 standards. Process 1700 may begin at block 1710.

[0064] At 1710, process 1700 may involve processor 1522 performing frame exchange with a first AP via transceiver 1526 for a coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission. Process 1700 may continue from 1710 to 1720.

[0065] At 1720, process 1700 may involve processor 1522 transmitting a Physical Layer Protocol Data Unit (PPDU) via transceiver 1526 based on the frame exchange, wherein the frame exchange includes an invitation frame received by the second AP from the first AP to invite the second AP to participate in a CoBF transmission or a CoSR transmission, a response frame sent by the second AP to the first AP in response to the invitation frame to indicate participation in the CoBF transmission or CoSR transmission, and a trigger frame received by the second AP from the first AP before transmitting the PPDU, wherein the trigger frame includes determined information for performing the CoBF transmission or CoSR transmission.

[0066] In some implementations, the invitation frame carries an indication to indicate whether the first AP should send an initial control frame to prepare one or more non-AP STAs associated with the first AP for reception. In some implementations, the trigger frame includes a user information field configured to carry the PPDU user information, and the AID field at the beginning of the user information field is not an AID field pointing to the associated non-AP STA in the coordinated transmission. In some implementations, the user information field is configured to carry information about one or more non-AP STAs in a single user information entry, and each of the one or more non-AP STAs includes at least one of a modulation and coding scheme (MCS), a 2×LDPC indication, and a Basic Service Set (BSS) flag.

[0067] In some implementations, all non-AP STAs scheduled to participate in the coordinated transfer, listed in the invitation and response frames, are presented in the preamble of the PPDU in the trigger frame and the coordinated transfer. In some implementations, if a non-AP STA scheduled to participate in the coordinated transfer by a second AP is unavailable, the non-AP STA is retained in the preamble of the trigger frame and the PPDU, while the data portion corresponding to that non-AP STA in the PPDU is omitted. In some implementations, the user order in the trigger frame is consistent with the user order in the UHR-SIG user field used for CoBF transfers.

[0068] Additional notes The topics described herein sometimes illustrate different components contained within or connected to other different components. It is important to understand that the architectures depicted are merely examples, and many other architectures can actually be implemented to achieve the same functionality. Conceptually, any arrangement of components that achieve the same functionality is effectively “associated” to achieve the desired function. Therefore, any two components combined here to achieve a particular function can be considered “associated” with each other to achieve the desired function, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered “operably connected” or “operably coupled” to each other to achieve the desired function, and any two components that can be so associated can also be considered “operably coupled” to each other to achieve the desired function. Specific examples of operational coupling include, but are not limited to, physically pairable and / or physically interacting components and / or wirelessly interactive components and / or logically interacting and / or logically interactive components.

[0069] Furthermore, regarding the use of virtually any plural and / or singular terms in this document, those skilled in the art can convert from plural to singular and / or from singular to plural depending on the context and / or application. For clarity, various singular / plural substitutions may be explicitly described herein.

[0070] Furthermore, those skilled in the art will understand that the terms generally used herein, particularly those used in the appended claims, such as the body of the appended claims, are generally intended as “open-ended” terms. For example, the term “comprising” should be interpreted as “including but not limited to,” the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” and so on. Those skilled in the art will further understand that if a specific number of introduced claim elements are intended, such intent will be explicitly stated in the claim, and in the absence of such a statement, such intent does not exist. For example, to aid understanding, the appended claims may contain the use of the introductory phrases “at least one” and “one or more” to introduce claim elements. However, the use of such phrases should not be construed as implying that the claim element introduced by the indefinite article “a” or “an” limits any particular claim containing such an introduced claim element to containing only one such element, even when the same claim contains the introductory phrase “one or more” or “at least one” and the indefinite article such as “a” or “an,” for example, “a” and / or “an” should be interpreted as referring to “at least one” or “one or more,” and the same applies to the use of definite articles used to introduce claim elements. Furthermore, even when a specific number of the introduced claim elements are explicitly stated, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the number listed. For example, the statement "two elements" without other modifiers means at least two elements or two or more elements. Additionally, in the use of phrases like "at least one of A, B, and C," for its purpose, such a structure is generally understood by those skilled in the art to be conventional. For example, "the system has at least one of A, B, and C" will include, but is not limited to, the system having a single A, a single B, a single C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. Similarly, in the use of phrases like "at least one of A, B, or C," for its purpose, such a structure is generally understood by those skilled in the art to be conventional. For example, "the system has at least one of A, B, or C" will include, but is not limited to, the system having a single A, a single B, a single C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. Those skilled in the art will further understand that any transitional words and / or phrases that actually represent two or more options, whether in the specification, claims, or drawings, should be understood to include the possibility of including one of a plurality of terms, any one of a plurality of terms, or two terms. For example, the phrase “A or B” will be understood to include the possibility of “A” or “B” or “A and B”.

[0071] As can be seen from the foregoing, it is understood that various embodiments of this application have been described herein for illustrative purposes, and various modifications may be made without departing from the scope and spirit of this application. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are determined by the appended claims.

[0072] While certain preferred embodiments and methods have been disclosed herein, those skilled in the art can make changes and modifications to these embodiments and methods without departing from the spirit and scope of the invention. Any modifications that do not depart from the spirit and scope of the invention are within the scope of the claims of this application.

Claims

1. A method for coordinating multi-access point transmission, comprising: The first access point (AP) and the second AP perform frame switching suitable for coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission; and The first AP exchanges and transmits Physical Layer Protocol Data Units (PPDUs) based on this frame. The frame exchange includes an invitation frame sent by the first AP to invite the second AP to participate in the coordination transmission, a response frame received by the first AP from the second AP in response to the invitation frame to indicate participation in the coordination transmission, and a trigger frame sent by the first AP to the second AP before sending the PPDU, wherein the trigger frame includes determined information for performing the coordination transmission.

2. The method of claim 1, wherein the invitation frame carries an indication for instructing the first AP whether to send an initial control frame to prepare one or more non-AP STAs associated with the first AP to receive.

3. The method of claim 2, wherein the initial control frame is transmitted between the response frame and the trigger frame.

4. The method of claim 1, wherein the trigger frame includes a user information field configured to carry user information of the PPDU, and the AID field at the beginning of the user information field is not an AID field pointing to an associated non-AP STA in the coordinated transmission.

5. The method of claim 4, wherein the user information field is configured to carry one or more non-AP STA information in a user information entry, and each of the one or more non-AP STA information includes at least one of modulation and coding scheme (MCS), 2×LDPC indicator, and basic service set (BSS) flag.

6. The method of claim 1, wherein all non-AP STAs listed in the invitation frame and the response frame that are scheduled to participate in the coordinated transmission are presented in the preamble of the PPDU in the trigger frame and the coordinated transmission.

7. The method of claim 6, wherein if a non-AP STA scheduled by the first AP to participate in the coordinated transmission is unavailable, the non-AP STA is retained in the preamble of the trigger frame and the PPDU, and the data portion of the PPDU corresponding to the non-AP STA is omitted.

8. The method of claim 1, wherein, The invitation frame is used to request the second AP and one or more non-AP STAs associated with the first AP to send a trigger-based PPDU, wherein the response frame from the second AP and the ICR from the one or more non-AP STAs are carried in the trigger-based PPDU.

9. The method of claim 1, wherein, The first response sent by the second AP in response to the invitation frame carries an indication of the location of the response frame carrying CoBF response information.

10. The method of claim 9, wherein the indication is used to indicate whether the response frame carrying CoBF response information is in the first response or in a subsequent intermediate coordination frame sent by the second AP.

11. The method of claim 7, wherein the non-AP STA is determined to be unavailable when the non-AP STA does not respond to the initial control frame sent by its associated AP, wherein the initial control frame is used to prepare the non-AP STA for reception.

12. The method of claim 1, further comprising: Receive trigger-based acknowledgments from one or more STAs associated with the first AP.

13. The method of claim 1, wherein the user order in the trigger frame is consistent with the user order in the UHR-SIG user field of the PPDU used for the coordinated transmission.

14. A device that can be implemented in an access point (AP), comprising: A transceiver configured for wireless communication; as well as A processor connected to the transceiver and configured to perform operations includes: The transceiver performs frame exchange with another AP for coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission; and The transceiver transmits Physical Layer Protocol Data Units (PPDUs) based on the frame exchange, wherein the frame exchange includes an invitation frame sent by the device to invite the other AP to participate in the coordinated transmission, a response frame received by the device from the other AP in response to the invitation frame to indicate participation in the coordinated transmission, and a trigger frame sent by the device to the other AP before transmitting the PPDU, wherein the trigger frame includes determined information for performing the coordinated transmission.

15. A method for coordinating multi-access point transmission, comprising: The second access point (AP) performs frame exchange with the first AP for coordinated transmission, wherein the coordinated transmission includes at least one of coordinated beamforming (CoBF) transmission and coordinated spatial multiplexing (CoSR) transmission; and The second AP exchanges and receives Physical Layer Protocol Data Units (PPDUs) based on this frame. The frame exchange includes an invitation frame received by the second AP from the first AP to invite the second AP to participate in the coordination transmission, a response frame sent by the second AP to the first AP in response to the invitation frame to indicate participation in the coordination transmission, and a trigger frame received by the second AP from the first AP before sending the PPDU, wherein the trigger frame includes determined information for performing the coordination transmission.

16. The method of claim 15, wherein the invitation frame carries an indication for instructing the first AP whether to send an initial control frame to prepare one or more non-AP STAs associated with the first AP to receive.

17. The method of claim 15, wherein, The trigger frame includes a user information field configured to carry the PPDU user information, and the AID field at the beginning of the user information field is not an AID field pointing to the associated non-AP STA in the coordinated transmission, wherein the user information field is configured to carry information of one or more non-AP STAs in a user information entry, and each of the one or more non-AP STAs includes at least one of modulation and coding scheme (MCS), 2×LDPC indicator, and basic service set (BSS) flag.

18. The method of claim 15, wherein, All non-AP STAs listed in the invitation frame and the response frame that are scheduled to participate in the coordination transfer are presented in the preamble of the PPDU in the trigger frame and the coordination transfer.

19. The method of claim 18, wherein, If a non-AP STA scheduled by the first AP to participate in the coordinated transmission is unavailable, the non-AP STA is retained in the preamble of the trigger frame and the PPDU, while the data portion of the PPDU corresponding to the non-AP STA is omitted.

20. The method of claim 15, wherein, The user order in this trigger frame is consistent with the user order in the UHR-SIG user field used for CoBF transmission.

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