Coordinate joint transmissions between multiple access points

Abstract

Methods, apparatus, and systems for coordinating joint transmissions between multiple access points are described. In one example aspect, a wireless communication method includes: receiving, by a communication device, a first frame from a primary access point or a first intermediate communication device. The first frame indicates a joint transmission to be performed by multiple access points. The first frame includes scheduling information for an auxiliary access point to perform the joint transmission, and an indicator that instructs the communication device to forward the scheduling information. The method also includes: sending, by the communication device, a second frame to the auxiliary access point or a second intermediate communication device. The second frame includes scheduling information for the auxiliary access point to perform the joint transmission.

Description

Technical Field

[0001] This patent application relates generally to wireless communications. Background Art

[0002] Mobile communications technology is driving the world towards an increasingly interconnected and networked society. Rapid growth and technological advancements in mobile communications are driving greater demand for capacity and connectivity. Other factors, such as energy consumption, device cost, spectrum efficiency, and latency, are also crucial to meeting the demands of various communication scenarios. Various technologies are being explored, including new approaches to providing higher quality of service, longer battery life, and improved performance. Summary of the Invention

[0003] This patent application describes, among other things, techniques for coordinating joint transmissions between multiple access points. Specifically, techniques are disclosed that enable stations to trigger joint transmissions by relaying scheduling information from a primary access point, and enable secondary access points or stations to facilitate joint transmissions.

[0004] In one embodiment, a wireless communication method is disclosed. The method includes receiving, by a communication device, a first frame from a first network device. The first frame indicates a joint transmission to be performed by multiple access points. The first frame includes scheduling information for assisting the access point to perform the joint transmission, and an indicator instructing the communication device to forward the scheduling information. The method also includes transmitting, by the communication device, a second frame to a second network device. The second frame includes scheduling information for assisting the access point to perform the joint transmission.

[0005] In another embodiment, a wireless communication method is disclosed. The method includes: a station accessing a medium to perform a transmission; and sending a frame by the station to a plurality of access points, the frame indicating a joint transmission to be performed by the plurality of access points. The frame includes scheduling information for the plurality of access points to perform the joint transmission.

[0006] In another embodiment, a wireless communication method is disclosed. The method includes receiving, by an access point, a frame from a communication device, the frame indicating a joint transmission to be performed by the access point. The frame includes scheduling information for the access point. The method also includes sending, after a predetermined duration, a joint transmission radio frame to a target station based on the scheduling information.

[0007] In another exemplary aspect, a communication device is disclosed, wherein the device includes a processor configured to implement the above method.

[0008] In yet another embodiment, a computer program storage medium is disclosed. The computer program storage medium includes code stored thereon. When executed by a processor, the code causes the processor to implement the described method.

[0009] This patent application describes these and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 An example architecture of a multi-AP system according to one or more embodiments of the disclosed technology is shown.

[0011] Figure 2A is a flowchart representation of a method of wireless communication in accordance with one or more embodiments of the disclosed technology.

[0012] Figure 2B is a flowchart representation of another method of wireless communication in accordance with one or more embodiments of the disclosed technology.

[0013] Figure 3 is a flowchart representation of yet another method of wireless communication in accordance with one or more embodiments of the disclosed technology.

[0014] Figure 4 An example multi-AP system is shown in accordance with one or more embodiments of the disclosed technology.

[0015] Figure 5A Another example multi-AP system in accordance with one or more embodiments of the disclosed technology is shown.

[0016] Figure 5B Another example multi-AP system in accordance with one or more embodiments of the disclosed technology is shown.

[0017] Figure 6A An example multi-AP system is shown in accordance with one or more embodiments of the disclosed technology.

[0018] Figure 6B The following diagrams are shown corresponding to one or more embodiments of the disclosed technology. Figure 6A An example of a transmission.

[0019] Figure 7A An example multi-AP system 700 is shown in accordance with one or more embodiments of the disclosed technology.

[0020] Figure 7B The following diagrams are shown corresponding to one or more embodiments of the disclosed technology. Figure 7A An example of a transmission.

[0021] Figure 8A Another example multi-AP system in accordance with one or more embodiments of the disclosed technology is shown.

[0022] Figure 8B Another example multi-AP system in accordance with one or more embodiments of the disclosed technology is shown.

[0023] Figure 9 Yet another example multi-AP system in accordance with one or more embodiments of the disclosed technology is shown.

[0024] Figure 10 An example of a wireless communication system is shown in which the technology according to one or more embodiments of the present technology can be applied.

[0025] Figure 11 is a block diagram representation of a portion of a wireless station in which techniques in accordance with one or more embodiments of the present technology may be applied. DETAILED DESCRIPTION

[0026] The section headings used in this patent application are intended solely for readability and are not intended to limit the scope of the embodiments and techniques disclosed in each section to that section. Certain features are described using the example of the Wi-Fi wireless protocol. However, the applicability of the disclosed techniques is not limited to Wi-Fi wireless systems.

[0027] In a wireless local area network (WLAN), common devices are classified as access points and stations (STAs). The WLAN basic service set (BBS) includes an access point (AP) and one or more stations (STAs). The AP usually accesses a wired / wireless network or can access or connect to a wired / wireless network that carries traffic in and out of the BSS. Generally speaking, STAs near the edge of AP coverage have poor link quality, which affects the transmission efficiency and reliability between the AP and the STA. With the rapid development of wireless technology, applications have put forward higher performance and reliability requirements for the network. Joint transmission by multiple APs can effectively improve transmission reliability and reduce latency. Wireless devices that support multi-AP configuration will gradually become popular. In order to promote joint transmission between multiple APs, it is expected to obtain scheduling information between multiple APs to ensure synchronization.

[0028] Figure 1 An example architecture of a multi-AP system according to one or more embodiments of the disclosed technology is shown. The multi-AP system 100 includes a master AP (M-AP) 101 and multiple secondary APs (S-APs) 103a, 103b. Devices 105, 107 support joint transmission by multiple APs in the multi-AP system 100. In this case, in order to successfully perform joint data transmission, the M-AP 101 schedules and synchronizes data transmission between the M-AP and the S-AP.

[0029] Figure 2A20 is a flowchart representation of a wireless communication method 200 according to one or more embodiments of the disclosed technology. The method 200 includes: at 202, a communication device (e.g., a station or a secondary AP) receives a first frame from a first network device (e.g., a primary AP or an intermediate AP / STA), the first frame indicating a joint transmission to be performed by multiple access points. The first frame includes scheduling information for the secondary access point to perform the joint transmission, and an indicator instructing the communication device to forward the scheduling information. The joint transmission can be, for example, a transmission performed simultaneously (e.g., occurring simultaneously) by the multiple access points. The method 200 includes: at 204, a communication device sends a second frame to a second network device (e.g., a secondary AP or an intermediate AP / STA). The second frame includes scheduling information for the secondary access point to perform the joint transmission.

[0030] Figure 2B 2 is a flowchart representation of a wireless communication method 250 according to one or more embodiments of the disclosed technology. The method 250 includes, at 252, accessing a medium by a station to perform a transmission. The method 250 also includes, at 254, sending a frame by the station to a plurality of access points, the frame indicating a joint transmission to be performed by the plurality of access points. The frame includes scheduling information for the plurality of access points to perform the joint transmission.

[0031] Figure 3 302 is a flowchart representation of another wireless communication method 300 according to one or more embodiments of the disclosed technology. The method 300 includes receiving, at 302, a frame by an access point (e.g., a primary access point) from a communication device (e.g., a station or a secondary access point), the frame indicating a joint transmission to be performed by the access point. The frame includes scheduling information for the access point. The method 300 also includes sending, at 304, a joint transmission radio frame to a target station after a predetermined duration based on the scheduling information.

[0032] Some examples of the disclosed technology are described in the following example embodiments.

[0033] Example 1

[0034] Figure 4 An example multi-AP system 400 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 400 includes three APs: AP1 is an M-AP, while AP2 and AP3 are S-APs.

[0035] After AP1 gains access to the medium using a contention-based protocol, it initiates a joint transmission with AP2. AP1 sends a scheduling frame 401 to AP2 to enable the joint transmission. This scheduling frame 401 can be a newly defined frame, such as a coordination trigger (CT) frame. This scheduling frame 401 can also utilize existing frame formats to include scheduling information. After a time interval 403 (e.g., SIFS), AP1 sends a joint transmission radio frame 411a to the STA.

[0036] When AP2 receives schedule frame 401, it determines that frame 401 originates from AP1. The schedule frame also includes an indicator (e.g., an overlapping BSS (OBSS) indicator) that instructs AP2 to decode the frame. After decoding schedule frame 401, AP2 obtains the scheduling information. After a time interval 405 (e.g., SIFS), AP2 sends a joint transmission radio frame 411b to the STA.

[0037] In this embodiment, AP3 does not receive the scheduling frame and continues to complete its current process without performing joint transmission with AP1.

[0038] Example 2

[0039] Figures 5A to 5B An example multi-AP system 500 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 500 includes two APs. AP1 is an M-AP, and AP2 is an S-AP. STAs can be used to relay information from the M-AP to the S-AP.

[0040] After AP1 gains access to the medium using a contention-based protocol, AP1 sends a scheduling frame 501 to the STA to enable joint transmission. The scheduling frame 501 can be a newly defined frame such as a CT frame. The scheduling frame 501 can also utilize existing frame formats to include scheduling information. The scheduling frame 501 includes scheduling information for AP2, such as parameters required by AP2's physical (PHY) layer and medium access control (MAC) layer. The scheduling information can help synchronize transmissions by AP1 and AP2. The scheduling frame 501 also includes a frame forwarding indicator to instruct the STA to forward / relay the scheduling information.

[0041] In some embodiments, the scheduling frame 501 includes the sequence number of the first data frame to be transmitted. In some embodiments, the scheduling frame 501 includes the buffer address of the data frame to be transmitted. The scheduling frame 501 may also indicate the status of the buffer in which the data frame is stored. In some embodiments, the STA may estimate the carrier frequency offset (CFO) during the scheduling frame and phase shift the subsequently received data.

[0042] After receiving the scheduling frame 501, based on the frame forwarding indicator, the STA determines that the information in the scheduling frame 501 needs to be forwarded to AP2. The STA generates a new scheduling frame 501' by partially or completely copying the received frame 501. Then, the STA performs one of the following operations:

[0043] 1. Such as Figure 5A As shown, the STA relays the scheduling information to AP2 by sending a new scheduling frame 501' after a time interval 503 (eg, SIFS). During the time interval 503, the STA suspends any Clear Channel Assessment (CCA).

[0044] 2. Such as Figure 5B As shown, STAs use access categories to contend for the medium for sending scheduling frames 501'. The priority levels in terms of contention-based channel access are called access categories (AC). The contention window (CW) can be set according to the expected traffic in each access category, where categories with larger traffic require wider windows. After obtaining medium access, the STA sends scheduling information to AP2 by sending a new scheduling frame 501' after the backoff interval 507. Note that the priority level associated with the access category is high enough to ensure that a time interval such as the arbitration interframe space (AIFS) plus the length of the backoff interval is shorter than the length of the data for joint transmission that is buffered at AP2.

[0045] After receiving the scheduling frame, AP1 detects that it is a frame forwarded by the STA and sends a joint transmission radio frame to the target station after a time interval 505 (eg, SIFS). During the time interval 505, AP1 suspends any clear channel assessment (CCA).

[0046] After AP2 receives the scheduling frame 501', AP2 obtains the scheduling information after decoding the frame. After a time interval 505 (e.g., SIFS), AP2 sends a joint transmission radio frame 511b to the target station. During the time interval 505, AP2 suspends any clear channel assessment (CCA).

[0047] When AP2 fails to receive the scheduling frame 501 ′, AP2 continues to complete the current process and does not perform joint transmission with AP1.

[0048] Example 3

[0049] Figures 6A to 6B An example multi-AP system 600 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 600 includes two APs. AP1 is an M-AP, and AP2 is an S-AP. Multiple STAs can be used to relay information from the M-AP to the S-AP.

[0050] After AP1 gains access to the medium using a contention-based protocol, it simultaneously sends a scheduling frame 601 to STA1 and STA2 to enable joint transmission. This scheduling frame 601 can be a newly defined frame, such as a CT frame. It can also utilize existing frame formats to include scheduling information. This scheduling frame 601 includes scheduling information for AP2, such as parameters required by AP2's PHY and MAC layers. This scheduling information helps synchronize transmissions by AP1 and AP2. This scheduling frame 601 also includes a frame forwarding indicator to instruct STAs to forward / relay scheduling information.

[0051] In some embodiments, the schedule frame 601 includes the sequence number of the first data frame to be transmitted. In some embodiments, the schedule frame 601 includes the buffer address of the data frame to be transmitted. The schedule frame 601 may also indicate the status of the buffer in which the data frame is stored. In some embodiments, STA1 and STA2 may estimate the carrier frequency offset (CFO) during the schedule frame and phase shift the subsequently received data.

[0052] After receiving the scheduling frame 601, STA1 and STA2 determine that the information in the scheduling frame 601 needs to be forwarded to AP2 based on the frame forwarding indicator. Both STA1 and STA2 generate new scheduling frames 601' and 601" by partially or completely copying the received frame 601. Figure 6BAs shown, STA1 relays scheduling information to AP2 by sending a new scheduling frame 601' after a time interval 603 (e.g., SIFS). Simultaneously, STA2 relays scheduling information to AP2 by sending a new scheduling frame 601" after a time interval 603 (e.g., SIFS). During the time interval 603, both STAs suspend any channel assessment (CCA).

[0053] After receiving the scheduling frame 601 ′ or 601 ″, AP1 detects that it is a frame forwarded by a STA and sends a joint transmission radio frame to the target station after a time interval 605 (eg, SIFS). During the time interval 605 , AP1 suspends any clear channel assessment (CCA).

[0054] When AP2 receives the scheduling frame 601′ or 601″, AP2 obtains the scheduling information after decoding the frame. After a time interval 605 (eg, SIFS), AP2 sends a joint transmission radio frame 511b to the target station. During the time interval 605, AP2 suspends any clear channel assessment (CCA).

[0055] When AP2 does not receive the scheduling frame 601' or 601", AP2 continues to complete the current process and does not perform joint transmission with AP1.

[0056] Example 4

[0057] 7A to 7B An example multi-AP system 700 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 700 includes three APs. AP1 is an M-AP, while AP2 and AP3 are S-APs. In this embodiment, a STA is located within the overlapping region of all APs. Therefore, the STA can initiate a joint transmission by multiple APs.

[0058] After a STA gains access to the medium using a contention-based protocol, the STA simultaneously sends a scheduling frame 701 to two or more APs (e.g., AP1 and AP2, AP1 and AP3, AP2 and AP3, or all three APs) to enable joint transmission. In this particular embodiment, the STA sends a scheduling frame 701 to all three APs to enable joint transmission. The scheduling frame 701 can be a newly defined frame such as a CT frame. The scheduling frame 701 can also utilize existing frame formats to include scheduling information. The scheduling frame 701 includes scheduling information for the intended APs (e.g., AP1 and AP2, AP1 and AP3, AP2 and AP3, or all three APs), such as parameters required by the PHY and MAC layers of the intended APs. The scheduling information can help synchronize transmissions by the APs (e.g., AP1 and AP2, AP1 and AP3, AP2 and AP3, or all three APs). The scheduling frame 701 also includes parameters for the data service requested by the STA.

[0059] In some embodiments, the scheduling frame 701 includes a sequence number of a first data frame to be sent. In some embodiments, the scheduling frame 701 includes a buffer address of a data frame to be sent. The scheduling frame 701 may also indicate the status of the buffer in which the data frame is stored.

[0060] After receiving the scheduling frame 701, AP1 decodes the frame and obtains its scheduling information. After a time interval 705 (e.g., SIFS), AP1 sends the joint transmission radio frame 711a requested by the STA. During the time interval 705, AP1 suspends any clear channel assessment (CCA).

[0061] Similarly, after AP2 and AP3 each receive scheduling frame 701, the corresponding AP (AP2 or AP3) decodes the frame and obtains its scheduling information. After a time interval 705 (e.g., SIFS), the corresponding AP sends joint transmission radio frames 711b and 771c in accordance with the STA's request. During time interval 705, the AP suspends any clear channel assessment (CCA).

[0062] When an AP (eg, AP1, AP2, or AP3) fails to receive the scheduling frame 701, the AP continues to complete the current process and does not perform joint transmission with the remaining AP(s).

[0063] Example 5

[0064] Figures 8A to 8BAn example multi-AP system 800 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 800 includes three APs. AP1 is an M-AP. AP2 and AP3 are S-APs. An S-AP can be used to relay information from the M-AP to (multiple) S-APs.

[0065] After AP1 gains access to the medium using a contention-based protocol, AP1 sends a scheduling frame 801 to AP2 to enable joint transmission among AP1, AP2, and AP3. The scheduling frame 801 can be a newly defined frame such as a CT frame. The scheduling frame 801 can also utilize an existing frame format to include scheduling information. The scheduling frame 801 includes scheduling information for AP2 and AP3, such as parameters required by the PHY layer and MAC layer of AP2 and AP3. The scheduling information can help synchronize transmissions performed by the APs (AP1, AP2, and AP3). The scheduling frame 801 also includes a frame forwarding indicator to instruct AP2 to forward / relay the scheduling information.

[0066] In some embodiments, the scheduling frame 801 includes a sequence number of a first data frame to be sent. In some embodiments, the scheduling frame 801 includes a buffer address of a data frame to be sent. The scheduling frame 801 may also indicate the status of the buffer in which the data frame is stored.

[0067] After receiving the scheduling frame 801, AP2 determines based on the frame forwarding indicator that the information in the scheduling frame 801 needs to be forwarded to AP2. AP2 then generates a new scheduling frame 801' by partially or completely copying the received frame 501. AP2 then performs one of the following operations:

[0068] 1. Such as Figure 8A As shown, AP2 relays the scheduling information to AP3 by sending a new scheduling frame 801' after a time interval 803 (e.g., SIFS). During the time interval 803, AP2 prohibits performing any carrier sensing (CS) operations, such as clear channel assessment (CCA) based on energy detection (ED) or virtual CS detection.

[0069] 2. Such as Figure 8B As shown, AP2 uses access categories to contend for the medium for sending scheduling frames 801'. After gaining access to the medium, the STA sends scheduling information to AP2 by sending a new scheduling frame 801' after a backoff interval 807. Note that the priority level associated with the access category is high enough to ensure that a time interval such as the arbitration interframe space (AIFS) plus the backoff interval is shorter than the length of the data buffer in AP3.

[0070] After receiving the scheduling frame, AP1 detects that it is a frame forwarded by AP2 and sends a joint transmission radio frame to the target station after a time interval 805 (eg, SIFS). During the time interval 805, AP1 suspends any clear channel assessment (CCA).

[0071] After receiving the scheduling frame 801', AP3 decodes the frame and obtains the scheduling information. After a time interval 805 (eg, SIFS), AP3 sends a joint transmission radio frame 811b to the target station. During the time interval 805, AP2 suspends any clear channel assessment (CCA).

[0072] When AP3 fails to receive the scheduling frame 801 ′, AP3 continues to complete the current process and does not perform joint transmission with AP1.

[0073] Example 6

[0074] Figure 9 An example multi-AP system 900 according to one or more embodiments of the disclosed technology is shown. The multi-AP system 900 includes two APs. AP1 is an M-AP, and AP2 is an S-AP. STAs can be used to relay information from the M-AP to the S-AP.

[0075] After AP1 gains access to the medium using a contention-based protocol, AP1 sends a scheduling frame to AP2 to enable joint transmission. The scheduling frame can be a newly defined frame, such as a CT frame. The scheduling frame can also utilize existing frame formats to include scheduling information. The scheduling frame includes scheduling parameters and / or a frame forwarding indicator. In some embodiments, the scheduling frame includes the sequence number of the first data frame that the M-AP expects the S-AP to jointly transmit.

[0076] In some embodiments, the scheduling parameters include resource unit (RU) information to indicate the RUs to be used by the S-AP to perform joint transmissions with the M-AP to the STA. In some embodiments, the frame forwarding indicator indicates whether the scheduled frame sent by the M-AP is to be forwarded by one or more intermediate devices. The frame forwarding indicator may include parameters such as the MAC address of the forwarding device and / or an indicator indicating whether the frame is a forwarded frame.

[0077] In this example, AP2 receives the scheduling frame and decodes the forwarding indication. AP2 learns that no forwarding is required. AP2 then decodes the RU information in the frame and determines that the specified one or more RUs will be used to perform a joint transmission to a specific STA after a specified time (e.g., SIFS). AP2 also obtains the sequence number of the first data frame to be sent to the specific STA. All of the above operations are completed within a specified time (e.g., SIFS). AP2 then performs the joint transmission based on the information in the scheduling frame.

[0078] In some cases, one or more intermediate devices may be required to forward the scheduling frame. When an intermediate device receives the scheduling frame, it decodes the forwarding indication and determines that it needs to perform a forwarding operation. The intermediate device fully or partially copies the scheduling parameters and / or sequence number of the first data frame that the M-AP expects the S-AP to jointly transmit to generate a new frame. The new frame may be marked as a forwarding frame and sent to one or more other intermediate devices or AP2. After AP2 receives the forwarded frame, it performs similar operations to transmit the data frame based on the information in the scheduling frame.

[0079] Figure 10 An example of a wireless communication system 1000 in which techniques according to one or more embodiments of the present technology can be applied is shown. The wireless communication system 1000 may include one or more base stations (BSs) 1005a, 1005b, one or more wireless devices 1010a, 1010b, 1010c, 1010d, and a core network 1025. The base stations 1005a, 1005b may provide wireless services to the wireless devices 1010a, 1010b, 1010c, and 1010d in one or more wireless sectors. In some embodiments, the base stations 1005a, 1005b include directional antennas to generate two or more directional beams to provide wireless coverage in different sectors.

[0080] The core network 1025 can communicate with one or more base stations 1005a and 1005b. The core network 1025 provides connectivity to other wireless communication systems and wired communication systems. The core network may include one or more service subscription databases to store information related to subscribed wireless devices 1010a, 1010b, 1010c, and 1010d. The first base station 1005a can provide wireless services based on a first radio access technology, while the second base station 1005b can provide wireless services based on a second radio access technology. Depending on the deployment scenario, base stations 1005a and 1005b can be quasi-co-located or separately installed on-site. Wireless devices 1010a, 1010b, 1010c, and 1010d can support multiple different radio access technologies.

[0081] Figure 11 1 is a block diagram representation of a portion of a wireless station. A wireless station 1105, such as a base station or a wireless device (or UE), may include processor electronics 1110, such as a microprocessor, that implements one or more of the wireless technologies presented in this application. The wireless station 1105 may include transceiver electronics 1115 to send and / or receive wireless signals via one or more communication interfaces, such as antennas 1120. The wireless station 1105 may include other communication interfaces for sending and receiving data. The wireless station 1105 may include one or more memories (not explicitly shown) configured to store information, such as data and / or instructions. In some embodiments, the processor electronics 1110 may include at least a portion of the transceiver electronics 1115. In some embodiments, at least some of the disclosed techniques, modules, or functions are implemented using the wireless station 1105.

[0082] It should be understood that this application discloses techniques that can be applied in a wireless communication system to facilitate synchronization between multiple APs for joint transmission. Using the disclosed techniques, an AP or station can relay scheduling information about a joint transmission to another AP. A station can also initiate a joint transmission itself and use a scheduling frame to synchronize the joint transmission.

[0083] In one example aspect, a wireless communication method includes receiving, by a communication device, a first frame from a first network device. The first network device is a primary access point or a first intermediate device (e.g., an intermediate AP / STA). The first frame indicates a joint transmission to be performed by multiple access points. The first frame includes scheduling information for a secondary access point to perform the joint transmission, and an indicator instructing the communication device to forward the scheduling information. The method also includes sending, by the communication device, a second frame to a second network device. The second network device is a secondary access point or a second intermediate device (e.g., an intermediate AP / STA). The second frame includes scheduling information for the secondary access point to perform the joint transmission.

[0084] In some embodiments, the transmission includes sending, by the communication device, a second frame to the secondary access point or a second intermediate communication device after a predetermined duration. In some embodiments, the predetermined duration is a minimum interface time span (SIFS). In some embodiments, the method further includes sending, by the communication device, the second frame to the primary access point after the predetermined duration.

[0085] In some embodiments, the scheduling information includes one or more physical layer transmission parameters or one or more medium access control (MAC) layer transmission parameters of the communication device or the second intermediate communication device. In some embodiments, the first frame indicates a sequence number of a data frame to be transmitted, a buffer address of a data frame to be transmitted, or a buffer status of the assisting access point. In some embodiments, the scheduling information includes information about resource units used by the assisting access point to perform the joint transmission.

[0086] In some embodiments, the method further includes: using the access category by the communication device to contend for the medium for sending the second frame, wherein the length of the arbitration interframe space (AIFS) of the access category plus the backoff time is shorter than the buffering period of the data in the second access point.

[0087] In some embodiments, the communication device comprises a station. In some embodiments, the communication device comprises a third access point. The method further comprises: after a predetermined time duration after sending the second frame, the communication device transmits a joint transmission radio frame to the target station. In some embodiments, the first frame comprises second scheduling information for the communication device to perform the joint transmission, the second scheduling information comprising one or more physical layer transmission parameters or one or more MAC layer transmission parameters of the communication device.

[0088] In another example aspect, a wireless communication method includes: accessing a medium by a station to perform a transmission, and sending a frame by the station to multiple access points indicating a joint transmission to be performed by the multiple access points. The frame includes scheduling information for the multiple access points to perform the joint transmission.

[0089] In some embodiments, the scheduling information includes one or more physical layer transmission parameters or one or more medium access control (MAC) layer transmission parameters of the plurality of access points.

[0090] In another example aspect, a wireless communication method includes receiving, by an access point, a frame from a communication device indicating a joint transmission to be performed by the access point. The frame includes scheduling information for the access point. The method further includes sending the joint transmission radio frame to a target station based on the scheduling information after a predetermined duration.

[0091] In some embodiments, the method includes suspending, by the access point, a clear channel assessment (CCA) for a predetermined duration after receiving the frame. The predetermined duration may be a shortest interface space (SIFS).

[0092] In some embodiments, the scheduling information includes information about resource units used by the assisting access point to perform the joint transmission. In some embodiments, the communication device includes a station or a second access point. The scheduling information includes one or more physical layer transmission parameters or one or more medium access control (MAC) layer transmission parameters of the access point.

[0093] The disclosed and other embodiments, modules, and functional operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware including the structures disclosed herein and their equivalents, or in a combination of one or more of these. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by or to control the operation of a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter that implements a machine-readable propagated signal, or a combination of one or more of these. The term "data processing apparatus" includes all devices, equipment, and machines for processing data, including, by way of example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus can include code that creates an execution environment for the computer program in question, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these. A propagated signal is an artificially generated signal, such as a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to a suitable receiver device.

[0094] A computer program (also referred to as a program, software, software application, script, or code) can be written in any form of programming language (including compiled or interpreted languages), and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored as part of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple collaborative files (e.g., files that store one or more modules, subroutines, or portions of code). A computer program may be deployed to execute on one computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communications network.

[0095] The processes and logic flows described herein may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and apparatus may be implemented as, special purpose logic circuitry, for example, an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0096] Processors suitable for executing computer programs include, for example, both general-purpose and special-purpose microprocessors, as well as any one or more processors of any type of digital computer. Generally speaking, a processor will receive instructions and data from read-only memory or random access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally speaking, a computer will also include one or more mass storage devices (e.g., magnetic, magneto-optical, or optical disks) for storing data, or be operatively coupled to one or more mass storage devices (e.g., magnetic, magneto-optical, or optical disks) for storing data, to receive data from or transfer data to the one or more mass storage devices, or both. However, a computer does not require such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices); magnetic disks (e.g., internal hard disks or removable disks); magneto-optical disks; and CD ROMs and DVD-ROMs. The processor and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0097] Although this patent application contains many details, these details should not be interpreted as limitations on the scope of any invention or what may be claimed, but rather as descriptions of features that are specific to particular embodiments of particular inventions. Certain features described in this patent application in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable subcombination. Moreover, although features may be described above as working in certain combinations, or even initially claimed as such, in some cases one or more features from a claimed combination may be excluded from that combination, and a claimed combination may be directed to a subcombination or a variation of a subcombination.

[0098] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that the operations be performed in the particular order shown, or in sequential order, or that all illustrated operations be performed, to achieve the desired results. Furthermore, the separation of various system components in the embodiments described in this patent application should not be understood as requiring such separation in all embodiments.

[0099] Only a few implementations and examples are described, and other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

Claims

1. A wireless communication method, the method comprising: receiving, by the communication device and another communication device, from a first network device, a first frame indicating joint transmission to be performed by a plurality of access points, wherein the first frame includes scheduling information for assisting the access point to perform the joint transmission, and an indicator instructing the communication device to forward the scheduling information; The communication device and the other communication device jointly generate respective second frames, wherein each second frame is a partial or complete copy of the first frame; jointly transmitting, by the communication device and the additional communication device, respective second frames to at least one second network device, wherein the second frames include scheduling information for the assisting access point to perform the joint transmission in response to detecting that at least one of the second frames is forwarded by the communication device; as well as The communication devices contend for a medium using an access category for transmitting the respective second frames, wherein a length of an arbitration interframe space (AIFS) plus a backoff time under the access category is shorter than a buffering period of data at the auxiliary access point. The method of claim 1 , wherein the first network device is a master access point. The method according to claim 1 , wherein the first network device is an intermediate access point or an intermediate station. 4 . The method according to claim 1 , wherein the second network device is the auxiliary access point. 5 . The method according to claim 1 , wherein the second network device is an intermediate access point or an intermediate station.

6. The method according to any one of claims 1 to 5, wherein the transmitting comprises: After a predetermined time duration, the communication device and the further communication device send respective second frames to the second network device. The method of claim 6 , wherein the predetermined duration is a Shortest Interface Space (SIFS).

8. The method according to claim 6 or 7, comprising: After the predetermined time duration, the communication device and the further network device transmit respective second frames to the master access point.

9. The method according to any one of claims 1 to 8, wherein the scheduling information comprises: One or more physical layer transmission parameters or one or more medium access control (MAC) layer transmission parameters of the communication device or the second network device.

10. The method according to any one of claims 1 to 9, wherein the first frame indicates a sequence number of a data frame to be transmitted, a buffer address of a data frame to be transmitted, or a buffer status of the assisting access point.

11. The method according to any one of claims 1 to 10, wherein the scheduling information comprises information on resource units used by the assisting access point to perform the joint transmission.

12. The method according to any one of claims 1 to 11, wherein the communication device comprises a station.

13. The method according to any one of claims 1 to 11, wherein the communication device comprises a third access point.

14. The method according to claim 13, comprising: A joint transmission radio frame is sent by the communication device to the target station after a predetermined time duration after sending the respective second frames.

15. The method according to claim 13, wherein the first frame includes second scheduling information for the communication device to perform the joint transmission, and the second scheduling information includes one or more physical layer transmission parameters or one or more MAC layer transmission parameters of the communication device.

16. A wireless communication method, the method comprising: Receiving, by an access point, a frame indicating that a joint transmission is to be performed by the access point, wherein the frame indicating that a joint transmission is to be performed by the access point is at least one of respective second frames jointly transmitted by at least two communication devices, wherein the second frame includes scheduling information for the access point, and the second frame is a partial or complete copy of a first frame jointly received by the at least two communication devices from a first network device, the first frame being used to indicate that a joint transmission is to be performed by a plurality of access points; detecting that the frame indicating that a joint transmission is to be performed by the access point is forwarded by the at least two communications devices; and After a predetermined duration, sending a joint transmission radio frame to the target station based on the scheduling information, The respective second frames are sent when the at least two communication devices use an access category to contend for a medium, and a length of an arbitration interframe space (AIFS) plus a backoff time under the access category is shorter than a buffering period of data at the access point.

17. The method according to claim 16, comprising: The access point suspends clear channel assessment (CCA) for a predetermined duration after receiving the frame.

18. The method according to claim 16 or 17, wherein the scheduling information includes information on resource units to be used by the access point to perform the joint transmission.

19. The method according to any one of claims 16 to 18, wherein at least one of the at least two communication devices comprises the station or another access point.

20. The method of any one of claims 16 to 19, wherein the scheduling information comprises one or more physical layer transmission parameters or one or more medium access control (MAC) layer transmission parameters of the access point.

21. A communication device comprising a processor configured to implement the method according to any one or more of claims 1 to 20.

22. A computer readable medium having stored thereon code which, when executed by a processor, causes the processor to implement the method according to any one or more of claims 1 to 20.

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