A method for a coordination transmission and an access-point device

Abstract

This invention provides a method for coordinating transmission. A first AP and a second AP exchange a first request and a first response. The first request is used to request the establishment of a first coordination protocol between the first AP and the second AP. The first response is used to indicate whether the establishment of the first coordination protocol between the first AP and the second AP is permitted or denied. If the establishment of the first coordination protocol between the first AP and the second AP is permitted, the first AP coordinates transmission with the second AP during the transmission opportunity period.

Description

[Technical Field]

[0001] This invention relates to wireless communication, and more particularly to a method for coordinating transmission and an access point (AP) device. [Previous Technology]

[0002] In traditional wireless communication systems (which include multiple access point (AP) devices and corresponding station (STA) devices), data transmission of AP devices is managed by a central controller of an upper-layer application. For example, this upper-layer central controller groups AP devices so that some AP devices in the same group can perform coordinated transmission.

[0003] However, the management scheme of the central controller may lack efficiency and flexibility. Furthermore, coordinated transmission between AP devices cannot be performed across different groups. For example, AP devices deployed and managed by a home group cannot coordinate transmission with AP devices in a neighboring area.

[0004] In view of the above problems, it is desirable to provide a decentralized mechanism to better facilitate the coordinated transmission of AP devices. [Summary of the Invention]

[0005] According to an embodiment of the present invention, a method for coordinating transmission is provided, comprising: a first AP exchanging a first request and a first response with a second AP, wherein the first request is for requesting the establishment of a first coordination protocol between the first AP and the second AP, and the first response is for indicating permission or denial of establishing the first coordination protocol between the first AP and the second AP; and if the establishment of the first coordination protocol between the first AP and the second AP is permitted, the first AP performing the coordinated transmission with the second AP during a transmission opportunity (TXOP).

[0006] According to another embodiment of the present invention, an access point (AP) is provided, comprising: a transceiver configured for wireless communication; and a processor coupled to the transceiver and configured to perform the following operations: exchanging a first request and a first response with a second AP via the transceiver, wherein the first request is for requesting the establishment of a first coordination protocol between the AP and the second AP, and the first response is for indicating permission to establish the first coordination protocol; and, if the establishment of the first coordination protocol between the AP and the second AP is permitted, performing the first coordinated transmission with the second AP via the transceiver during a transmission opportunity (TXOP).

Implementation Method

[0008] Figure 1 is a schematic diagram of a communication system 1000 according to an embodiment of the present invention. The communication system 1000 includes a plurality of access point (AP) devices. In the example of Figure 1, the communication system 1000 exemplary includes seven AP devices 100-106 (the number of AP devices is not limited to the example of Figure 1). Each AP device 100-106 can wirelessly communicate with a corresponding station (STA) device (not shown in Figure 1) according to the Wi-Fi standard.

[0009] In the operation of the communication system 1000, AP devices 100-106 can compete for a transmission opportunity (TXOP), and AP device 101 can obtain the TXOP. Furthermore, AP device 101 can establish a coordination agreement with another AP device (e.g., AP device 102), where establishing a coordination agreement between AP device 101 and AP device 102 signifies the establishment of a coordination pair between AP device 101 and AP device 102. Then, AP device 101 and the other AP device (e.g., AP device 102) can perform coordinated transmission during the TXOP, meaning that AP device 101 and AP device 102 coordinately send data to their respective STAs during the TXOP. Coordinated transmission can be of various types, including coordinated spatial reuse (CSR) transmission, coordinated beamforming (CBF) transmission, and coordinated time division multiple access (CTDMA) transmission, etc. Through coordinated transmission, AP device 102 and AP device 101 can send data within the same time period TXOP. Since AP device 101 acquires the TXOP in this embodiment, AP device 101 is considered to share the TXOP with AP device 102. Therefore, AP device 101 is referred to as the "sharing AP device," while AP device 102 is referred to as the "shared AP device."

[0010] Each AP device 100-106 can maintain a list to record the identifiers of the coordinating APs that form a coordination pair with it. Such a list is called a "Multi-AP (MAP) list". For example, AP device 101 (which obtains TXOP and therefore acts as a shared AP device) records the identifier of AP device 102 in the MAP list.

[0011] Furthermore, the coordination protocol between the two AP devices can be dismantled. That is, the coordination pair can be dynamically adjusted. For example, AP devices 101 and 102 initially establish a coordination protocol (i.e., form a coordination pair). However, AP device 102 may dismantle the original coordination pair with AP device 101 when necessary, and AP device 102 can form a new coordination pair with AP device 103 to perform coordinated transmission.

[0012] Figure 2A is a block diagram of one of the AP devices 100-106 in Figure 1, with AP device 101 as an example. As shown in Figure 2A, AP device 101 includes a processor 10, a storage unit 20, and a transceiver 30. The processor 10 can be any type of hardware processor, such as a central processing unit (CPU), a micro control unit (MCU), or a digital signal processor (DSP). The processor 10 is operatively coupled to the storage unit 20 and the transceiver 30 so that the processor 10 can be configured to access the storage unit 20 and control the transceiver 30.

[0013] Transceiver 30 may include a transmitter and a receiver for sending and receiving messages from AP device 101. These messages are used to perform handshakes to establish or dismantle coordination pairs formed by AP device 101 and other AP devices. Similarly, transceiver 30 is also used to send and receive data from AP device 101, such as data transmitted between AP device 101 and corresponding STA devices.

[0014] Figure 2B is a block diagram of storage unit 20 in Figure 2A. Storage unit 20 can be any type of hardware storage device or memory device, such as a hard disk, flash drive, random access memory (RAM), and read-only memory (ROM), etc. Storage unit 20 can be integrated into processor 10. Storage unit 20 can be used to store basic information required for AP device 101 to establish and dismantle coordination protocols (i.e., coordination pairs) and perform coordination transmissions. For example, storage unit 20 can store MAP list m1 of AP device 101. Processor 10 of AP device 101 can be configured to access MAP list m1 in storage unit 20 so that AP device 101 can add the identifier of AP forming a coordination pair with AP device 101 to MAP list m1 or remove the identifier of AP from MAP list m1.

[0015] Figure 2C is a schematic diagram illustrating messages sent and received by transceiver 30. As shown in Figure 2C, messages may include broadcast messages (e.g., beacon frames BCN), request messages (REQ), response messages (RSP), and leave messages (LEV). In one example, request messages (REQ), response messages (RSP), and leave messages (LEV) may be implemented using "management frames" in the Wi-Fi standard.

[0016] The broadcast message contains information about the coordination capabilities of the AP device 101. Coordination capabilities can indicate whether the AP device 101 can support coordinated transmissions with other AP devices. In some embodiments, coordination capabilities can indicate the types of coordinated transmissions supported by the AP device, wherein the coordinated transmission types include at least one of CSR transmission, CBF transmission, and CTDMA transmission. In one example, the processor 10 of the AP device 101 can be configured to control the transceiver 30 to periodically broadcast broadcast messages.

[0017] Furthermore, the REQ request is called a "Coordination Protocol Establishment Request" and is used to request the establishment of a coordination protocol with another AP device. The Coordination Protocol Establishment Request can also be called a Coordination Transport Pairing Request. For example, the processor 10 of AP device 101 can be configured to control transceiver 30 to send a REQ request to the transceiver (not shown) of AP device 102, requesting the establishment of a coordination pair with AP device 102.

[0018] Furthermore, the response RSP is called a "Coordination Protocol Establishment Response" and is used to respond to a request REQ sent by another AP device. The Coordination Protocol Establishment Response can also be called a Coordination Transport Pairing Response. The response RSP can indicate "allow" or "deny" of the request to establish a coordination pair. For example, when transceiver 30 of AP device 101 receives a request REQ sent by AP device 102, transceiver 30 of AP device 101 can send a response RSP to AP device 102. If the response RSP indicates "deny" of establishing a coordination pair with AP device 102, then the coordination pair between AP devices 101 and 102 is not successfully established.

[0019] On the other hand, if the transceiver 30 of AP device 101 sends a response RSP indicating "allow" to AP device 102, a coordination pair will be established between AP devices 101 and 102, and the identifier of AP device 102 will be recorded in the MAP list m1 in the storage unit 20 of AP device 101. Accordingly, the identifier of AP device 101 is also recorded in the MAP list in the storage unit (not shown) of AP device 102.

[0020] The Leave Message LEV (sent by transceiver 30 of AP device 101) is used to notify the coordinating AP device that AP device 101 tends to dismantle the established coordination protocol (i.e., dismantle the established coordination pair). Similarly, if transceiver 30 of AP device 101 receives the Leave Message LEV from another AP device (e.g., AP device 102), AP device 101 may also dismantle the coordination protocol with that other AP device (e.g., AP device 102) (i.e., dismantle the established coordination pair). In other words, regardless of whether AP device 101 sends the Leave Message LEV to another AP device or receives the Leave Message LEV from another AP device, AP device 101 will dismantle the coordination pair with that other AP device.

[0021] Figure 3A is a schematic diagram illustrating the operation of beacon frame BCN between AP devices 101, 102, and 103. As shown in Figure 3A, each AP device 101, 102, and 103 can periodically broadcast beacon frame BCN, and the broadcast beacon frame BCN can be received by neighboring AP devices. For example, AP device 101 broadcasts a beacon frame BCN, which is received by neighboring AP device 102 (the beacon frame BCN sent by AP device 101 may not reach AP device 103, which is farther away from AP device 101). Similarly, AP device 103 broadcasts a beacon frame BCN, which is received by neighboring AP device 102, but may not be received by AP device 101.

[0022] In addition, AP device 102 located between AP devices 101 and 103 broadcasts a beacon frame BCN, which can be received by the neighboring AP devices 101 and 103 respectively.

[0023] Based on the beacon frame BCN from AP device 101, AP device 102 can understand the coordination capabilities of AP device 101 to determine the coordination transmission types that AP1 can support (e.g., CSR transmission, CBF transmission, or CTDMA transmission, etc.). Based on the beacon frame BCN from AP device 103, AP device 102 can understand the coordination capabilities of AP device 103 to determine the coordination transmission types that AP3 can support (e.g., CSR transmission, CBF transmission, or CTDMA transmission, etc.). Similarly, AP device 101 can also understand the coordination capabilities of AP device 102 based on the beacon frame BCN from AP device 102 to determine the coordination transmission types that AP2 can support. Similarly, AP device 103 can also understand the coordination capabilities of AP device 102 based on the beacon frame BCN from AP device 102 to determine the coordination transmission types that AP2 can support.

[0024] Figure 3B is a schematic diagram illustrating the operation of request REQ and response RSP between AP devices 101, 102, and 103. As shown in Figure 3B, AP device 102 has a need for coordinated transmission, and AP device 102 understands that the neighboring AP device 101 can support coordinated transmission (based on the beacon frame BCN from AP device 101). Therefore, AP device 102 can send a request REQ to AP device 101, requesting to establish a coordinated pair with AP device 101.

[0025] When AP device 101 receives a REQ request, if AP device 101 is able to perform the coordination transmission within the upcoming time period, AP device 101 can respond to AP device 102 with a "allow" response RSP. Through the handshake achieved by the REQ request and the RSP response, a coordination pair will be established between AP devices 101 and 102. Furthermore, the identifiers of AP devices 101 and 102 will be recorded in each other's MAP lists. That is, AP device 101's MAP list can record the identifier of the coordinating AP device 102, and AP device 102's MAP list can correspondingly record the identifier of the coordinating AP device 101.

[0026] Similarly, AP device 102 can receive a request REQ from AP device 103, which requests the establishment of a coordination pair with AP device 102. After receiving the request REQ, if AP device 102 is able to perform a coordination transfer within the following time period, AP device 102 can reply to AP device 103 with a response RSP indicating "allow". The handshake achieved through the request REQ and response RSP will establish a coordination pair between AP devices 103 and 102. In addition, the identifiers of AP devices 103 and 102 will be recorded in each other's MAP lists. That is, AP device 102's MAP list will not only include the previously recorded identifier of AP device 101, but will also add the identifier of AP device 103 to AP device 102's MAP list.

[0027] Then, if one of AP devices 101 and 102 acquires the TXOP, the AP device holding the TXOP can share the TXOP with the other AP device 101 and 102. Therefore, AP devices 101 and 102 can perform coordinated transmissions (e.g., CSR transmissions, CBF transmissions, or CTDMA transmissions) within this TXOP. In some embodiments, if AP device 102 acquires the TXOP, AP device 102 can simultaneously perform coordinated transmissions with both AP devices 101 and 103.

[0028] Any AP device in a coordination pair may be inclined to dismantle the coordination pair under certain circumstances. For example, in one case, if an AP device in the coordination pair does not need to send data within a predetermined time period, that AP device may be inclined to dismantle its coordination pair. For example, when AP 102 has no data to send, AP 102 may send a leave message to AP 101 and remove AP 101 from AP device 102's MAP list. AP 101 receives the leave message and removes AP 102 from AP device 101's MAP list.

[0029] In another scenario, if one AP device in a coordination pair detects an overall performance degradation in the coordination transmission, that AP device may also tend to tear up its coordination pair. The coordination pair may be torn up based on a leave message LEV, which will be discussed in the following paragraphs with reference to Figure 3C. In some embodiments, when AP device 101 (or AP device 103) and AP device 102 are performing a coordination transmission, if AP device 101 (or AP device 103) detects an overall performance degradation, AP device 101 (or AP device 103) may remove AP device 102 from its MAP list. AP device 101 (or AP device 103) may send a leave message to AP device 102. AP device 102 then removes AP device 101 (or AP device 103) from its MAP list. Alternatively, when AP device 101 (or AP device 103) and AP device 102 are performing a coordinated transfer, AP device 102 detects an overall performance degradation and sends a leave message to AP device 101 (or AP device 103). AP device 102 removes AP device 101 (or AP device 103) from its MAP list, and AP device 101 (or AP device 103) can then remove AP device 102 from its MAP list. The overall performance of the coordinated transfer degrades if the combined data throughput of the two APs during the coordinated transfer is less than the data throughput of one of the APs before the coordinated transfer. For example, if one of the two APs originally had a data throughput of 500 Mbps, and the combined data throughput of the two APs is 400 Mbps, the overall performance of the coordinated transfer will degrade.

[0030] After AP devices 101, 102, and 103 are added to each other's MAP lists, AP devices 101, 102, and 103 can maintain a validity period in the MAP lists. Information about this validity period can be included in the response RSP or request REQ. For example, after the identifier of AP device 102 is added to the MAP list of AP device 101, AP device 102 can maintain a validity period in the list. A coordinated transmission pairing response from AP device 101 to AP device 102 may contain information indicating the validity period of AP 102. Alternatively, a coordinated transmission pairing request from AP device 102 to AP device 101 may contain information indicating the validity period of AP device 102. If AP 101 deems the validity period inappropriate, AP 101 can assign an updated validity period to AP 102. The validity period can be a multiple of the target-beacon-transmission-time (TBTT). Therefore, in another scenario of dismantling a coordination pair between two AP devices, when either of the two AP devices detects that the validity period of one of the AP devices in the coordination pair has expired, the expired AP device may be removed from the corresponding AP's MAP list, and the coordination pair between the two AP devices will be dismantled. For example, when the validity period of AP device 102 expires, AP device 101 removes the identifier of AP device 102 from its own MAP list.

[0031] Figure 3C is a schematic diagram illustrating the operation of the LEV message of AP device 103. As shown in Figure 3C, if AP device 103 does not need to transmit data within a predetermined time period, or if AP device 103 detects an overall performance degradation in the coordinated transmission with AP device 102, AP device 103 may tend to dismantle the coordinated pair with AP device 102.

[0032] AP device 103 can send a Leave Message (LEV) to AP device 102, and the identifier of AP device 102 will be removed from the MAP list of AP device 103. Therefore, the coordination pair between AP devices 102 and 103 is torn down, and the MAP list of AP device 103 shows "NULL", which means that AP device 103 does not establish a coordination protocol with any AP device.

[0033] Furthermore, after AP device 102 receives the Leave Message LEV, AP device 102 can remove the identifier of AP device 103 from its MAP list. Therefore, the MAP list of AP device 102 only records the identifier of AP device 101. In other words, when AP device 103 sends the Leave Message LEV, or when the coordinating AP device 102 receives the Leave Message LEV from AP device 103, the coordination pair between AP devices 102 and 103 will be torn down.

[0034] Figure 4 is a flowchart illustrating a method for coordinated transmission between AP devices 101, 102, and 103 according to an embodiment of the present invention. The coordinated transmission method shown in Figure 4 can be performed by AP device 102 in the communication system 1000 of Figure 1, and can correspond to the examples shown in Figures 3A to 3C. As shown in Figure 4, firstly, in step S400, AP device 102 receives a broadcast message (e.g., a beacon frame BCN) containing coordination capability information of AP device 101 (corresponding to the example in Figure 3A) from AP device 101. Based on the coordination capability information contained in the broadcast message (e.g., the beacon frame BCN) from AP device 101, AP device 102 can determine that AP device 101 can support coordinated transmission. In some embodiments, in step S400, AP device 102 also receives a broadcast message (e.g., a beacon frame BCN) containing coordination capability information of AP device 103 from AP device 103. Based on the coordination capability information contained in the broadcast message (e.g., beacon frame BCN) from AP device 103, AP device 102 can determine that AP device 103 can support coordinated transmission.

[0035] Then, in step S402, when AP device 102 has a need for coordinated transmission and tends to establish a coordinated pair with AP device 101, AP device 102 can send a request REQ to AP device 101 to request the establishment of a coordinated pair (corresponding to the example in Figure 3B), where the request REQ can be a coordinated transmission pairing request. Then, in step S404, AP device 102 can receive a response RSP from AP device 101 (corresponding to the example in Figure 3B), where the response RSP can be a coordinated transmission pairing response. When the response RSP of AP device 101 indicates "allow" to establish a coordinated pair with AP device 102, step 406 is executed. In step S406, AP device 102 adds the identifier of AP device 101 to the MAP list of AP device 102. Then, in step S408, AP device 102 can perform coordinated transmission with AP device 101. For example, AP device 102 and AP device 101 can simultaneously send data to their respective STA devices.

[0036] Then, in step S410, the AP device 102 may remove the coordination pair with the AP device 101 if the AP device 102 does not need to send data within a predetermined time period, or if the AP device 102 detects an overall performance degradation of the coordinated transmission with the AP device 101 . The coordination pair can be removed by triggering the departure message LEV sent by the AP device 102 (not shown in the example of Figure 3C). Alternatively, if the AP equipment 101 tends to remove the coordination pair, the AP equipment 102 may receive the departure message LEV from the AP equipment 101 and once the AP equipment 102 receives the departure message LEV, the coordination pair is removed. In addition, AP device 102 removes the identification of AP device 101 from the MAP list of AP device 102 .

[0037] On the other hand, in step S404, when the response RSP of the AP device 101 instructs “reject” to establish a coordination pair with the AP device 102 , it means that the AP device 102 cannot perform a coordinated transmission with the AP device 101 . Therefore, step S412 will be performed. In step S412, the AP device 102 may request other AP devices to establish coordination pairs to perform coordinated transmissions. For example, the AP device 102 may send a request REQ to the AP device 103 to establish a coordination pair (corresponding to the example of Figure 3B) based on the coordination capability information contained in the broadcast message from the AP device 103 .

[0038] Then, in step S414, the AP device 103 replies to respond to the RSP, instructing "Allow" to establish a coordination pair with the AP device 102. The AP device 102 adds the identifier of the AP device 103 to the MAP list of the AP device 102 . Then, in step S416, AP devices 102 and 103 may perform coordinated transmissions.

[0039] FIG. The coordinated transmission method shown in FIG.5 may be performed by AP equipment 101 in the communication system 1000 of FIG. As shown in FIG. The AP device 102 may determine that the AP device 101 can support coordinated transmissions based on the coordination capabilities contained in a broadcast message from the AP device 101 (e.g., beacon frame BCN). Then, in step S502, the AP device 101 may receive a request REQ from AP device 102 for requesting to establish a coordination pair, wherein the request REQ may be a coordinated transmission pairing request.

[0040] Then, in step S504, AP device 101 determines whether AP device 101 has a need for coordinated transmission and tends to establish a coordinated pair with AP device 102. When AP device 101 has a need for coordinated transmission and tends to establish a coordinated pair with AP device 102, step 506 is executed. In step S506, AP device 101 may reply to AP device 102 with a response RSP indicating "allow" to establish the coordinated pair requested by AP device 102, wherein the response RSP may be a coordinated transmission pairing response. In addition, AP device 101 adds the identifier of AP device 102 to AP device 101's MAP list. Then, in step S508, AP device 101 and AP device 102 perform coordinated transmission, such that AP device 101 and AP device 102 can simultaneously send data to their respective STA devices within the TXOP obtained by AP device 101 or AP device 102.

[0041] Then, in step S510, if AP device 101 does not need to send data within a predetermined time period or detects an overall performance degradation in the coordinated transmission with AP device 102, AP device 101 may send a Leave Message LEV to AP device 102 to dismantle the coordinated pair. Alternatively, if AP device 102 prefers to dismantle the coordinated pair, AP device 101 will receive a Leave Message LEV from AP device 102, and the coordinated pair will be dismantled. Furthermore, AP device 101 removes the identifier of AP device 102 from its MAP list.

[0042] On the other hand, in step S504, when AP device 101 determines that it has no need for coordinated transmission, step 512 will be executed. In step S512, AP device 101 will reply to AP device 102 with a response RSP, indicating "reject" to establish a coordinated pair.

[0043] Figure 6 is a timeline diagram showing the three phases of communication between AP devices 101 and 102. As shown in Figure 6, the communication between AP devices 101 and 102 may include a setup phase, a negotiation phase, and a transmission phase.

[0044] During the setup phase, AP devices 101 and 102 may broadcast a broadcast message (e.g., a beacon frame BCN) to notify each other of their coordination capabilities. Through the broadcast message (e.g., a beacon frame BCN), AP devices 101 and 102 can exchange information about their coordination capabilities to understand whether AP device 101 and / or AP device 102 can support performing coordinated transmissions. In some embodiments, coordination capabilities may indicate supported coordinated transmission types, wherein coordinated transmission types include at least one of CSR transmissions, CBF transmissions, and CTDMA transmissions.

[0045] If AP devices 101 and 102 support coordinated transmission, one of AP devices 101 and 102 can send a request REQ to request the establishment of a coordination protocol between AP devices 101 and 102. Furthermore, the other AP device 101 and 102 can reply with a response RSP to the request REQ. If the response RSP indicates "allow," a coordination protocol can be established for AP devices 101 and 102, and then AP devices 101 and 102 can add each other's identifiers to their respective MAP lists (i.e., AP device 101 adds the identifier of AP device 102 to its own MAP list, and AP device 102 adds the identifier of AP device 101 to its own MAP list). Establishing a coordination protocol between AP devices 101 and 102 signifies the establishment of a coordination pair between AP devices 101 and 102.

[0046] AP device 101 (or AP device 102) may be assigned an identifier. This identifier may be an "association identifier (AID)". In one example, the AID may be included in the response RSP. For example, when AP device 101 receives a response RSP from AP device 102, AP device 101 can obtain the AID of AP device 102 from the response RSP, and then AP device 101 can add the AID of AP device 102 to its MAP list. In one example, the AID may be included in the request RSP. For example, AP device 102 may send a request to AP device 101 containing the AID of AP device 102.

[0047] Alternatively, AP devices 101 and 102 can assign AIDs to each other. For example, AP 101 can assign an AID to AP 102, and AP 102 can assign an AID to AP 101.

[0048] Subsequently, in the negotiation phase following the setup phase, AP devices 101 and 102 can exchange operational information with each other. In one example, the operational information of each AP device may include the configuration of the corresponding STA device attached to that AP device. In the example of Figure 6, STA device 10 is attached to AP device 101, while another STA device 20 is attached to AP device 102, as indicated by the aforementioned configuration. In one example, the operational information of each AP device may include parameters related to coordinated transmission. These parameters can help determine whether coordinated (CBF, CSR, or CTDMA) transmission can be successful.

[0049] Furthermore, the operational information may include the transmission power associated with the AP devices in AP devices 101 and 102. More specifically, the transmission power may be indicated by RSSI information. For example, when a STA device 10 attached to AP device 101 receives a signal from AP device 101, STA device 10 may perform an RSSI measurement to obtain RSSI information associated with AP device 101. STA device 10 may then provide the RSSI information to AP device 101. AP device 101 may inform AP device 102 of the RSSI information of STA device 10. Therefore, based on the RSSI information, AP device 102 may control the power of the transmission signals sent to its corresponding STA device 20 to avoid interfering with the transmission of STA device 10.

[0050] Then, in the transmission phase following the negotiation phase, AP device 101 obtains the TXOP in the contention window and is referred to as the shared AP. AP device 101 may send a "MU-RTS" frame containing the AID and MAC address of AP device 102 to notify AP 101 that a coordinated transmission will be performed and what kind of coordinated transmission will be performed, such as a CSR transmission.

[0051] AP 102 receives MU-RTS from AP 101 and sends a “CTS” frame to AP 101. STA 10 receives MU-RTS from AP 101 and sends a “CTS” frame to AP 101.

[0052] Following the “CTS” frame, AP devices 101 and 102 can simultaneously send a “coordinated PPDU” to their respective STA devices. The “coordinated PPDU” can carry a data payload. In one example, the transceiver of each AP device 101 and 102 can be used to send the “coordinated PPDU”. Taking AP device 101 as an example, referring back to Figure 2A, the processor 10 of AP device 101 can be configured to control the transceiver 30 to send the “coordinated PPDU”.

[0053] After completing the "coordinated PPDU" transmission of AP 101, STA 10 can send a "BA" frame to AP 101 to acknowledge the "coordinated PPDU" transmission of AP 101. After completing the "coordinated PPDU" transmission of AP 102, STA 20 can send a "BA" frame to AP 102 to acknowledge the "coordinated PPDU" transmission of AP 102.

[0054] Figure 7 is a schematic diagram illustrating the coordination pairs between AP devices 100-106 in Figure 1. The identifier (e.g., AID) recorded in the MAP list of each AP device 100-106 is the identifier (e.g., AID) of the associated AP device with which it has established a cooperative transmission pair. In the example of Figure 7, when a cooperative transmission pair is established between AP device 101 and AP device 100, the identifier (e.g., AID) of AP 100 is recorded in MAP list m1 of AP 101, and the identifier (e.g., AID) of AP 101 is recorded in MAP list m0 of AP 100.

[0055] Figure 8 is a schematic diagram of a method for coordinated transmission between AP devices 101, 102, and 103 according to another embodiment of the present invention. As shown in Figure 8, the first AP device 101 is configured to broadcast a first broadcast message (e.g., a beacon frame BCN1) containing its coordination capabilities. The coordination capabilities of the first AP device 101 indicate the coordination transmission types supported by the first AP device 101. Furthermore, the first AP device 101 is configured to receive a second broadcast message (e.g., a beacon frame BCN2) containing the coordination capabilities of a second AP device 102, which indicates the coordination transmission types supported by the second AP device 102. The coordination transmission types include at least one of CSR transmission, CBF transmission, and CTDMA transmission.

[0056] Subsequently, the first AP device 101 is configured to exchange a first request and a first response with the second AP device 102. The first request is used to request the establishment of a first coordination protocol between the first AP device 101 and the second AP device 102. The first response is used to indicate whether the establishment of the first coordination protocol between the first AP device 101 and the second AP device 102 is permitted or denied. In one example, the first AP device 101 receives a first request (e.g., request REQ2) from the second AP device 102, and the first AP device 101 sends a first response (e.g., response RSP1) to the second AP device 102. In another example, the first AP device 101 sends a first request (e.g., request REQ1) to the second AP device 102, and the first AP device 101 receives a first response (e.g., response

[0070] ) from the second AP device 102. Further, if the establishment of a first coordination protocol between the first AP device 101 and the second AP device 102 is permitted, the first AP device 101 records the identifier (e.g., AID) of the second AP device 102 in the first AP device 101's first coordination transmission AP list (e.g., first MAP list m1). Similarly, the identifier (e.g., AID) of the first AP device 101 is recorded in the second coordination transmission AP list (e.g., second MAP list m2) of the second AP device 102.

[0057] Furthermore, after establishing a first coordination protocol between the first AP device 101 and the second AP device 102, AP device 101 and the second AP device 102 exchange operational information. This operational information includes information about the STA devices belonging to the corresponding devices in the first AP device 101 and the second AP device 102, as well as parameters related to the coordinated transmission, which can help determine whether the coordinated transmission (CBF, CSR, or CTDMA) can be successful. Additionally, if the second AP device 102 obtains a TXOP, the first AP device 101 receives an RTS frame (e.g., MU-RTS2) from the second AP device 102. Alternatively, if the first AP device 101 obtains a TXOP, the first AP device 101 sends an RTS frame (e.g., MU-RTS1) to the second AP device 102. The RTS frame indicates which type of coordinated transmission should be performed during the TXOP. When either the first AP device 101 or the second AP device 102 acquires TXOP, the first AP device 101 and the second AP device 102 can perform coordinated transmission during the TXOP period.

[0058] When a degradation in the overall performance of the coordinated transmission is detected, the first AP device 101 sends a first departure message (e.g., departure message LEV1) to the second AP device 102 or receives a second departure message (e.g., departure message LEV2) from the second AP device 102 to dismantle the first coordination protocol between the first AP device 101 and the second AP device 102. Alternatively, when the first AP device 101 detects that the validity period of the second AP device 102 maintained in the first MAP list m1 has expired, it deletes the identifier of the second AP device 102 from the first MAP list m1 of the first AP device 101.

[0059] In some examples, the first AP device 101 can also establish a coordination protocol with other AP devices besides the second AP device 102 (e.g., the third AP device 103). Specifically, the first AP device 101 exchanges a second request (e.g., request REQ1, for requesting the establishment of a second coordination protocol between the first AP device 101 and the third AP device 103) and a second response (e.g., response RSP3, for indicating permission or denial of establishing a second coordination protocol between the first AP device 101 and the third AP device 103). When the establishment of a first coordination protocol between the first AP device 101 and the second AP device 102 is permitted, and the establishment of a second coordination protocol between the first AP device 101 and the third AP device 103 is permitted, and the first AP device 101 obtains a TXOP, during the TXOP period, the first AP device 101 coordinates transmissions with the second AP device 102 and the third AP device 103.

[0060] The first AP device 101 may be referred to as the "first AP", and the second AP device 102 may be referred to as the "second AP". In some embodiments, AP1 can form a coordinated transmission pair with any nearby AP. When AP1 wants to form a coordinated transmission pair with a nearby AP, it does not need to obtain the consent of the APs in its MAP list.

[0061] Figure 9 is a flowchart of a coordinated transmission method for multiple access points according to an embodiment of the present invention. The method may include the following steps:

[0062] In step S900, the first AP and the second AP exchange a first request and a first response. The first request is used to request the establishment of a first coordination agreement between the first AP and the second AP. The first response is used to indicate whether the establishment of the first coordination agreement is permitted or denied.

[0063] In one example, step S900 may include: receiving a first request from the second AP and sending a first response to the second AP. In another example, step S900 may include: sending a first request to the second AP and receiving a first response from the second AP.

[0064] In step S902, if the establishment of a first coordination protocol between the first AP and the second AP is permitted, the first AP coordinates transmission with the second AP during TXOP.

[0065] Specifically, after a first coordination protocol is established between the first AP and the second AP, when either the first AP or the second AP obtains a TXOP, the first AP coordinates transmission with the second AP during the TXOP period.

[0066] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the invention. Specifications and examples are provided by way of illustration only, and the true scope of the invention is indicated by the following claims and their equivalents. [Simplified Explanation of the Diagram]

[0007] Figure 1 is a schematic diagram of a communication system 1000 according to an embodiment of the present invention. Figure 2A is a block diagram of one of the AP devices 100-106 in Figure 1, wherein AP device 101 is taken as an example. Figure 2B is a block diagram of the storage unit 20 in Figure 2A. Figure 2C is a schematic diagram showing messages sent and received by transceiver 30. Figure 3A is a schematic diagram showing beacon frame BCN operation between AP devices 101, 102 and 103. Figure 3B is a schematic diagram showing request REQ and response RSP operation between AP devices 101, 102 and 103. Figure 3C is a schematic diagram showing the leave message LEV operation performed by AP device 103. Figure 4 is a flowchart of a method for coordinating transmission between AP devices 101, 102 and 103 according to an embodiment of the present invention. Figure 5 is a flowchart of a method for coordinating transmission between AP devices 101, 102 and 103 according to another embodiment of the present invention. Figure 6 is a timing diagram illustrating the three stages of coordinated transmission between AP devices 101 and 102. Figure 7 is a schematic diagram illustrating the coordination pair between AP devices 100-106 in Figure 1. Figure 8 is a schematic diagram of a method for coordinated transmission between access point devices 101, 102, and 103 according to an embodiment of the present invention. Figure 9 is a flowchart of a method for coordinated transmission between multiple access points according to an embodiment of the present invention. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown schematically for the purpose of simplifying the illustrations.

Claims

1. A method for coordinating transmissions, comprising: A first access point (AP) exchanges a first request and a first response with a second AP, wherein the first request is for requesting the establishment of a first coordination protocol between the first AP and the second AP, and the first response is for indicating whether to allow or deny the establishment of the first coordination protocol between the first AP and the second AP; if the establishment of the first coordination protocol between the first AP and the second AP is allowed, the first AP performs the coordinated transmission with the second AP during a transmission opportunity (TXOP); And send a first leave message to the second AP to terminate the first coordination protocol between the first AP and the second AP, or receive a second leave message from the second AP to terminate the first coordination protocol between the first AP and the second AP.

2. The method as described in claim 1, wherein after the establishment of the coordination protocol between the first AP and the second AP is permitted, the coordination transfer is performed during the TXOP when either the first AP or the second AP acquires the TXOP.

3. The method as described in request item 1, wherein the step of exchanging the first request and the first response with the second AP includes: Receive the first request from the second AP; Send the first response to the second AP.

4. The method as described in request item 1, wherein the step of exchanging the first request and the first response with the second AP includes: Send the first request to the second AP; Receive the first response from the second AP.

5. The method as described in claim 1, wherein the method further comprises: The broadcast includes a first broadcast message that includes the coordination capabilities of the first AP, wherein the coordination capabilities of the first AP indicate the coordination transport types supported by the first AP; the reception includes a second broadcast message that includes the coordination capabilities of the second AP, wherein the coordination capabilities of the second AP indicate the coordination transport types supported by the second AP.

6. The method of claim 5, wherein the coordinated transmission type includes at least one of coordinated spatial reuse (CSR) transmission, coordinated beamforming (CBF) transmission, and coordinated time division multiple access (CTDMA) transmission.

7. The method as described in claim 1, wherein when an overall performance degradation of the coordinated transmission is detected, the first AP sends the first leave message to the second AP or receives the second leave message from the second AP.

8. The method as described in claim 1, further comprising: If the establishment of the first coordination protocol is permitted, the identifier of the second AP is stored in the coordination transmission AP list of the first AP, and the identifier of the second AP is deleted from the coordination transmission AP list of the first AP when it is detected that the validity period of the second AP being maintained in the first MAP list has expired.

9. The method of claim 1, wherein after the establishment of the first coordination protocol between the first AP and the second AP is permitted, the method further comprises: The first AP exchanges operational information with the second AP, wherein the operational information includes information about multiple stations (STAs) attached to the respective AP and parameters related to the coordinated transmission.

10. The method as described in claim 2, further comprising: The first AP and the third AP exchange a second request and a second response, wherein the second request is for requesting the establishment of a second coordination protocol between the first AP and the third AP, and the second response is for indicating whether to allow or refuse to establish the second coordination protocol between the first AP and the third AP; And if the establishment of the first coordination protocol between the first AP and the second AP and the establishment of the second coordination protocol between the first AP and the third AP are permitted and the TXOP is obtained by the first AP, the first AP performs the coordinated transmission with the second AP and the third AP during the TXOP.

11. The method as described in claim 2, further comprising: If the second AP acquires the TXOP, the first AP receives an RTS from the second AP, wherein the RTS is used to notify the type of coordinated transmission to be performed during the TXOP; or, if the first AP acquires the TXOP, the first AP sends an RTS to the second AP, wherein the RTS is used to notify the type of coordinated transmission to be performed during the TXOP.

12. An access point (AP), comprising: A transceiver is configured to wirelessly send and receive data and messages; The transceiver and the processor, coupled to the transceiver and configured to perform the following operations: exchange a first request and a first response with a second AP via the transceiver, wherein the first request is for requesting the establishment of a first coordination protocol between the AP and the second AP, and the first response is for indicating permission to establish the first coordination protocol. If the establishment of the first coordination protocol between the AP and the second AP is permitted, the first coordinated transmission is performed with the second AP via the transceiver during a transmission opportunity (TXOP); Send a first leave message to the second AP to terminate the coordination protocol between the AP and the second AP, or receive a second leave message from the second AP to terminate the coordination protocol between the AP and the second AP.

13. The AP as described in claim 12, wherein the TXOP is obtained by the AP or the second AP after the establishment of the first coordination protocol is permitted.

14. The AP as described in request item 12, wherein exchanging the first request and the first response with the second AP includes: The first request is received from the second AP, and the first request is used to request the establishment of a coordination protocol with the AP. The first response is sent to the second AP, the first response indicating permission to establish the first coordination protocol between the AP and the second AP.

15. The AP as described in request item 12, wherein exchanging the first request and the first response with the second AP includes: Send the first request to the second AP, the first request being used to request the establishment of a first coordination protocol with the second AP; The first response is received from the second AP, and the first response is used to indicate permission to establish the first coordination protocol between the AP and the second AP.

16. The AP as claimed in claim 12, wherein the processor is further configured to: broadcast a first broadcast message including the coordination capabilities of the AP device, wherein the coordination capabilities of the AP include coordination transport types supported by the AP; and receive a second broadcast message including the coordination capabilities of a second AP, wherein the coordination capabilities of the second AP include coordination transport types supported by the second AP.

17. The AP as claimed in claim 12, wherein the processor is further configured to: exchange a second request and a second response with a third AP via the transceiver, wherein the second request is for requesting the establishment of a second coordination protocol between the AP and the third AP, and the second response is for indicating permission or denial of establishing the second coordination protocol between the AP and the third AP; and, if the establishment of the first coordination protocol between the AP and the second AP and the establishment of the second coordination protocol between the AP and the third AP are permitted and the TXOP is obtained by the AP, perform the coordinated transmission with the second AP and the third AP via the transceiver during the TXOP.

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