WO2022121681A1 - 触发帧发送方法及装置 - Google Patents

触发帧发送方法及装置 Download PDF

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Publication number
WO2022121681A1
WO2022121681A1 PCT/CN2021/132490 CN2021132490W WO2022121681A1 WO 2022121681 A1 WO2022121681 A1 WO 2022121681A1 CN 2021132490 W CN2021132490 W CN 2021132490W WO 2022121681 A1 WO2022121681 A1 WO 2022121681A1
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Prior art keywords
link
mld
trigger frame
ppdu
moment
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PCT/CN2021/132490
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English (en)
French (fr)
Inventor
李伊青
李云波
郭宇宸
于健
淦明
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华为技术有限公司
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Priority to EP21902388.4A priority Critical patent/EP4247048A4/en
Publication of WO2022121681A1 publication Critical patent/WO2022121681A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/04—Scheduled access
    • H04W74/06—Scheduled access using polling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/04—Arrangements for maintaining operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H04L1/1614—Details of the supervisory signal using bitmaps
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/15—Setup of multiple wireless link connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present application relates to the field of wireless communication technologies, and in particular, to a trigger frame sending method and apparatus.
  • a multi-link device that supports ML communication has the ability to transmit and receive on multiple links, so that MLD can utilize a larger bandwidth for data transmission, which is beneficial to significantly improve throughput.
  • a link may refer to a spatial path through which the MLD performs data transmission in a frequency band.
  • STR MLDs can be divided into STR MLDs and non-STR MLDs according to whether they have the ability to transmit and receive simultaneously (simultaneous transmitting and receiving, STR) on different links.
  • STR MLDs are STR capable, non-STR MLDs are not STR capable.
  • Embodiments of the present application provide a trigger frame sending method and device, which can implement error recovery related to trigger frames in the scenario of non-STR MLD communication.
  • a first aspect provides a method for sending a trigger frame, the method comprising: a multi-link device MLD sends a first trigger frame through a first link at a first moment, and sends a second trigger through a second link at the first moment frame, the transmission end time of the first trigger frame is aligned with the transmission end time of the second trigger frame; the MLD fails to receive the first trigger frame-based physical layer protocol data triggered by the first trigger frame through the first link.
  • the MLD is sent through the first link at the second moment A third trigger frame, and a fourth trigger frame is sent through the second link at a third time instant, and the second time instant is aligned with the third time instant.
  • the MLD sends the third trigger frame through the first link at the second moment, and sends the fourth trigger frame through the second link at the third moment. It can be seen that when an error related to the first trigger frame occurs on the first link, the MLD can also send the next trigger frame (that is, the third trigger frame) on the first link, so as to realize the Error recovery. In addition, since the second moment and the third moment are aligned, the third trigger frame and the fourth trigger frame are sent synchronously, so as to reduce the probability that the MLD needs to send and receive data at the same time, and ensure that the MLD can communicate normally.
  • the method further includes: the MLD performs a block ack (block ack, BA) on the second TB PPDU. ) to detect the channel state of the first link after the transmission end time.
  • block ack block ack, BA
  • the MLD sends the third trigger frame through the first link at the second moment, including: within the first preset time interval after the first link ends the transmission of the BA of the second TB PPDU In the idle state, the MLD sends a third trigger frame through the first link at the second moment. Based on this design, information transmitted by the MLD on the first link can be prevented from colliding with information transmitted by other devices on the first link.
  • the time interval between the third moment and the end moment of transmission of the BA of the second TB PPDU is equal to the first preset time interval.
  • the first preset time interval is a point coordination function interframe space (PIFS).
  • PIFS point coordination function interframe space
  • the method further includes: the MLD performs a backoff process on the first link; When the backoff counter of the link backs off to 0 before the transmission start time of the BA of the second TB PPDU, the MLD keeps the backoff counter of the first link at 0 until the BA transmission of the second TB PPDU is completed; The channel state of the first link is detected from the time when the transmission of the BA of the two TB PPDU ends.
  • the MLD sends the third trigger frame through the first link at the second moment, including: within a second preset time interval after the first link ends the transmission of the BA of the second TB PPDU In the idle state, the MLD sends a third trigger frame through the first link at the second moment.
  • the time interval between the third moment and the end moment of transmission of the BA of the second TB PPDU is equal to the second preset time interval.
  • the second preset time interval is a short interframe space (SIFS). Based on this design, it is equivalent to modify the time that the back-off process needs to wait after switching from busy to idle from AIFS defined in the related art to SIFS, so as to ensure that the second time and the third time can be aligned, thereby ensuring that the MLD is in the first chain. can be sent synchronously on the channel and the second link.
  • SIFS short interframe space
  • the method further includes: the MLD sends a dummy (dummy) through the first link at the fourth moment. ) frame, the transmission start time of the BA of the second TB PPDU at the fourth moment is aligned, and the length of the dummy frame is the same as the length of the BA of the second TB PPDU. Based on this design, the TXOP of the MLD on the first link is maintained by sending the dummy frame, so that the MLD can send the next trigger frame on the first link.
  • the method before the MLD sends the dummy frame through the first link at the fourth moment, the method further includes: the MLD determines that the first link is in an idle state in the PIFS before the fourth moment.
  • the method before the MLD sends the dummy frame through the first link at the fourth moment, the method further includes: the MLD performs a backoff process on the first link; when the backoff counter of the first link is at the second TB PPDU When the backoff counter of the first link reaches 0 before the transmission start time of the BA, the MLD keeps the backoff counter of the first link at 0 until the fourth time.
  • the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link, including: the MLD determines that the transmission of the first trigger frame fails.
  • the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link, including: the MLD determines that an error occurs in the received first TB PPDU.
  • a second aspect provides a method for sending a trigger frame, the method comprising: a multi-link device MLD sends a first trigger frame through a first link at a first moment, and sends a second trigger through a second link at the first moment frame, the transmission end time of the first trigger frame is aligned with the transmission end time of the second trigger frame; the transmission of the first trigger frame fails, and the MLD successfully receives the second TB triggered by the second trigger frame through the second link
  • the MLD transmits the third trigger frame through the first link at the second time; the second time is located after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU.
  • the MLD when an error occurs in the first TB PPDU triggered by the first trigger frame, and the second TB PPDU triggered by the second trigger frame is successfully received on the second link, the MLD will be in the second link.
  • the third trigger frame is sent through the first link at the moment. It can be seen that when an error related to the first trigger frame occurs on the first link, the MLD can also send the next trigger frame (that is, the third trigger frame) on the first link, so as to realize the Error recovery.
  • the second time is located after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU, so as to avoid the adverse effect of the BA of the second TB PPDU on the error recovery on the first link,
  • the error recovery of the first link can be performed normally.
  • the MLD since the MLD does not need to receive data on the second link during the period after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU, the MLD does not need to receive data during this period.
  • Sending the third trigger frame can reduce the probability that the MLD needs to send and receive data at the same time, and ensure that the MLD can communicate normally.
  • the method further includes: the MLD determines that the first link is in an idle state in the PIFS before the second moment.
  • the method further includes: the MLD performs a backoff procedure on the first link; when the backoff counter of the first link backs off to 0 before the second time instant , the MLD keeps the backoff counter of the first link at 0 until the second moment.
  • the second moment is aligned with the start moment of transmission of the BA of the second TB PPDU.
  • the second moment is aligned with the transmission end moment of the second TB PPDU.
  • an MLD including: a processing module and a communication module connected to the processing module.
  • the communication module is used to send the first trigger frame through the first link at the first moment, and send the second trigger frame through the second link at the first moment, the transmission end moment of the first trigger frame and the second trigger frame.
  • the transfer end time is aligned.
  • the processing module is further configured to fail to receive the first trigger frame-based physical layer protocol data unit TB PPDU triggered by the first trigger frame through the first link when the MLD fails, and successfully receive through the second link the first trigger frame-based physical layer protocol data unit TB PPDU.
  • the control communication module sends the third trigger frame through the first link at the second moment, and sends the fourth trigger frame through the second link at the third moment.
  • the moment is aligned with the third moment.
  • the processing module is further configured to confirm the end of the transmission of the BA in the block of the second TB PPDU after the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link.
  • the channel state of the first link is detected after the time.
  • the communication module is used for, when the first link is in an idle state in the first preset time interval after the transmission end moment of the BA of the second TB PPDU, at the second moment through the first link.
  • a link sends a third trigger frame.
  • the time interval between the third moment and the end moment of transmission of the BA of the second TB PPDU is equal to the first preset time interval.
  • the first preset time interval is PIFS.
  • the processing module is also used to perform a backoff process on the first link after the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link;
  • the backoff counter of a link backs off to 0 before the transmission start time of the BA of the second TB PPDU
  • the backoff counter of the first link is kept at 0 until the BA transmission of the second TB PPDU is completed;
  • the channel state of the first link is detected from the moment when the transmission of the BA of the TB PPDU ends.
  • the communication module is used for, when the first link is in an idle state in a second preset time interval after the transmission end moment of the BA of the second TB PPDU, at the second moment through the first link.
  • a link sends a third trigger frame.
  • the time interval between the third moment and the end moment of transmission of the BA of the second TB PPDU is equal to the second preset time interval.
  • the second preset time interval is SIFS.
  • the communication module is further configured to send the dummy frame through the first link at the fourth moment after the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link.
  • the transmission start time of the BA of the second TB PPDU at the fourth moment is aligned, and the length of the dummy frame is the same as the length of the BA of the second TB PPDU.
  • the processing module is further configured to determine that the first link is in an idle state in the PIFS before the fourth moment before the communication module sends the dummy frame through the first link at the fourth moment.
  • the processing module is also used to perform the backoff process on the first link; when the backoff counter of the first link backs off to 0 before the transmission start time of the BA of the second TB PPDU, the The backoff counter for a link remains at 0 until the fourth time instant.
  • the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link, including: the MLD determines that the transmission of the first trigger frame fails.
  • the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link, including: the MLD determines that an error occurs in the received first TB PPDU.
  • a communication device comprising: a processing module and a communication module connected to the processing module.
  • the communication module is used to send the first trigger frame through the first link at the first moment, and send the second trigger frame through the second link at the first moment, the transmission end moment of the first trigger frame and the second trigger frame.
  • the transfer end time is aligned.
  • the processing module is further configured to control the communication module to pass the first TB PPDU at the second moment when the transmission of the first trigger frame fails and the MLD successfully receives the second TB PPDU triggered by the second trigger frame through the second link.
  • the link sends a third trigger frame; the second time instant is located after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU.
  • the processing module is further configured to, after determining that the transmission of the first trigger frame fails, determine that the first link is in an idle state in the PIFS before the second moment.
  • the processing module is further configured to perform a back-off process on the first link after determining that the transmission of the first trigger frame fails; when the back-off counter of the first link backs off to 0 before the second moment , the backoff counter of the first link is kept at 0 until the second moment.
  • the second moment is aligned with the start moment of transmission of the BA of the second TB PPDU.
  • the second moment is aligned with the transmission end moment of the second TB PPDU.
  • a communication device in a fifth aspect, includes a processor and a transceiver, and the processor and the transceiver are used to implement the method provided by any one of the first aspect or the second aspect.
  • the processor is configured to perform processing actions in the corresponding method
  • the transceiver is configured to perform the actions of receiving/transmitting in the corresponding method.
  • a computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes the design provided in the first aspect or the second aspect. method.
  • a seventh aspect provides a computer program product comprising computer instructions that, when the computer instructions are executed on a computer, cause the computer to perform the method provided by any one of the first aspect or the second aspect.
  • a chip including: a processing circuit and a transceiver pin, where the processing circuit and the transceiver pin are used to implement the method provided by any one of the first aspect or the second aspect.
  • the processing circuit is used for executing the processing actions in the corresponding method
  • the transceiver pins are used for executing the actions of receiving/transmitting in the corresponding method.
  • FIG. 1 is a schematic diagram of a back-off process in the related art
  • FIG. 2 is a schematic diagram of a communication scenario between an AP multi-link device and a STA multi-link device according to an embodiment of the present application;
  • Figure 3 (a) and Figure 3 (b) are schematic structural diagrams of AP multi-link devices and STA multi-link devices participating in communication;
  • Fig. 4 is the schematic diagram that the PIFS error recovery mechanism is applied to the trigger frame error scene in the related art
  • Fig. 5 is the schematic diagram that the back-off error recovery mechanism in the related art is applied to the trigger frame error scene
  • FIG. 6 is a flowchart of a trigger frame sending method provided by an embodiment of the present application.
  • FIG. 7 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 12 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 13 is a flowchart of another trigger frame sending method provided by an embodiment of the present application.
  • FIG. 14 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 15 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 16 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • 17 is a schematic diagram of another scenario of triggering frame transmission provided by an embodiment of the present application.
  • FIG. 18 is a schematic structural diagram of a communication device according to an embodiment of the present application.
  • FIG. 19 is a schematic structural diagram of another communication apparatus provided by an embodiment of the present application.
  • the technical solutions provided in this application can be applied to various communication systems, for example, systems using the IEEE 802.11 standard.
  • the IEEE 802.11 standard includes, but is not limited to, the 802.11be standard, or the next-generation 802.11 standard.
  • the applicable scenarios of the technical solution of the present application include: communication between AP and STA, communication between AP and AP, and communication between STA and STA.
  • the STAs involved in this application may be various user terminals, user devices, access devices, subscriber stations, subscriber units, mobile stations, user agents, user equipment or other names with wireless communication functions, wherein the user terminals may include various A handheld device, vehicle-mounted device, wearable device, computing device, or other processing device connected to a wireless modem with wireless communication capabilities, as well as various forms of user equipment (UE), mobile station (MS) , terminal, terminal equipment, portable communication device, handset, portable computing device, entertainment device, gaming device or system, global positioning system device or any other suitable device configured to communicate via a wireless medium over a network equipment, etc.
  • UE user equipment
  • MS mobile station
  • terminal equipment terminal equipment
  • portable communication device handset
  • portable computing device portable computing device
  • entertainment device gaming device or system
  • gaming device or system global positioning system device
  • the access point AP involved in this application is a device deployed in a wireless communication network to provide wireless communication functions to its associated STA.
  • the access point AP can be used as the center of the communication system, and can be a base station, a router , gateway, repeater, communication server, switch or bridge and other communication equipment, wherein the base station may include various forms of macro base station, micro base station, relay station and so on.
  • the devices mentioned above are collectively referred to as access points AP.
  • TXOP Transmission Opportunity
  • TXOP is the basic unit of wireless channel access.
  • TXOP consists of an initial time and a maximum duration (TXOP limit).
  • TXOP limit The station that obtains the TXOP can no longer compete for the channel again within the TXOP limit time, and continuously use the channel to transmit multiple data frames.
  • TXOP can be obtained through competition or distribution by a hybrid coordinator (HC). Among them, the TXOP obtained through competition may be called an enhanced distributed channel access (EDCA) TXOP. The TXOP obtained via HC allocation may be referred to as a hybrid coordination function controlled channel access (HCCA) TXOP.
  • HCCA hybrid coordination function controlled channel access
  • IFS Interframe space
  • the 802.11 protocol stipulates that after the device finishes sending, it must wait for a short period of time before sending the next frame. This period of time is the inter-frame interval.
  • the length of the interframe space depends on the type of frame the device is sending. High-priority frames need to wait for a shorter time, so they can get the right to send first, but low-priority frames must wait for a longer time.
  • the inter-frame interval provides different priorities for wireless medium access, and the different priorities are divided according to the time length of the inter-frame interval.
  • the time between frames is arranged from small to large as follows:
  • Short interframe space short interframe space, SIFS
  • AIFS Arbitration interframe space
  • the error recovery includes PIFS error recovery and back-off error recovery, which will be introduced separately below.
  • PIFS error recovery After the idle time of the channel reaches PIFS, the device sends the next PPDU on the channel.
  • the carrier sense mechanism can be divided into a physical carrier sense mechanism and a virtual carrier sense mechanism.
  • the physical carrier sensing mechanism is also called clear channel assessment (CCA).
  • CCA clear channel assessment
  • the target device first receives data on this channel. If after a given time, the target device does not find other devices sending data on this channel, the target device starts to send data; if it finds that other devices are sending data, the target device randomly avoids for a period of time and retry the process again.
  • Clear channel assessment includes packet detection and energy detection. Among them, packet detection is to detect whether there is data packet transmission on the channel (it can be judged by detecting whether there is a packet header). If there is a data packet on the channel and the energy exceeds a packet detection threshold, the channel is considered busy. Energy detection is to detect the energy on the channel. If the energy on the channel is greater than or equal to the energy detection threshold, the channel is considered busy. When the result of the packet detection and the result of the energy detection are both the channel is idle, the channel is considered to be in an idle state. In other words, if the packet header is not detected within a certain period of time, and the energy on the channel during energy detection is less than the energy detection threshold, the channel is considered to be in an idle state.
  • the virtual carrier sense mechanism uses information found in 802.11 frames to predict the state of the wireless medium.
  • virtual carrier sense is provided by NAV.
  • a device can maintain one or more NAVs.
  • NAV itself is a timer, set by using the duration value in the MAC header of the frame. The value of NAV decreases over time.
  • a non-zero NAV indicates that the wireless medium is busy.
  • NAV is zero, indicating that the wireless medium is idle.
  • the above-mentioned wireless medium may be a channel, a frequency band, or the like.
  • NAV is set by using the duration value in the MAC header of the frame.
  • the current NAV value of the station the station can update the NAV according to the duration field in the received frame. If the receiving address of the frame is the station, it means that the station is the receiving station, or the value of the duration field in the frame is less than or equal to the current NAV value of the station, the NAV cannot be updated.
  • the NAV value is calculated from the end time of the received radio frame.
  • the IEEE 802.11 standard supports multiple users to share the same transmission medium, and the sender checks the availability of the transmission medium before sending data.
  • the IEEE 802.11 standard uses carrier sense multiple access with collision avoidance (CSMA/CA) to achieve channel competition. Among them, in order to avoid collision, CSMA/CA adopts a back-off mechanism.
  • the backoff mechanism on a single channel is described below.
  • the device Before the device sends a message, the device can select a random number from 0 to the contention window (CW), and use the random number as the initial value of the backoff counter.
  • the idle time of the channel After the idle time of the channel reaches the arbitration inter-frame space (AIFS), when the channel is idle for every timeslot (timeslot), the count value of the backoff counter is decremented by 1.
  • the back-off counter suspends counting.
  • the backoff counter resumes counting.
  • the back-off process ends, and the device can start data transmission.
  • the back-off counter starts to back off. Whenever the channel is in an idle state in a time slot, the count value of the back-off counter is decremented by 1 until the count value of the back-off counter is 0. After the count value of the backoff counter is 0, the device successfully competes for the channel, and the device can send PPDUs on the channel.
  • WiFi next-generation wireless fidelity
  • EHT extremely high throughput
  • the multiple frequency bands or multiple channels may be collectively referred to as multiple links.
  • a multi-link device includes one or more subordinate sites, and the subordinate sites may be logical sites or physical sites.
  • a multi-link device includes a subordinate station may be briefly described as “a multi-link device includes a station”.
  • the affiliated station may be an access point (access point, AP) or a non-access point station (non-access point station, non-AP STA).
  • access point access point
  • non-access point station non-access point station
  • a multi-link device whose subordinate site is an AP may be referred to as a multi-link AP, or an AP MLD, or a multi-link AP device; the subordinate site may be a multi-link device of a STA. It is called multi-link STA, or multi-link STA device, or STA MLD, or non-AP MLD.
  • Multi-link devices can implement wireless communication following the 802.11 protocol.
  • the 802.11 protocol may be the 802.11ax protocol, the 802.11be protocol, and the next-generation 802.11 protocol, and the embodiment of the present application is not limited thereto.
  • Multilink devices can communicate with other devices.
  • other devices may be multi-link devices or may not be multi-link devices.
  • FIG. 2 is a schematic diagram of a communication scenario between an AP multi-link device and a STA multi-link device.
  • an AP multi-link device can associate with multiple STA multi-link devices and single-link STAs.
  • the AP multilink device 100 is associated with the STA multilink device 200 , the STA multilink device 300 , and the STA400 .
  • multiple APs in the AP multi-link device work on multiple links respectively
  • multiple STAs in the STA multi-link device work on multiple links respectively
  • one STA in the STA multi-link device works on multiple links.
  • a single-link STA is associated with an AP in the AP multi-link device on its working link.
  • the frequency bands in which the multi-link device operates may include but are not limited to: sub 1GHz, 2.4GHz, 5GHz, 6GHz and high frequency 60GHz.
  • Figures 3(a) and 3(b) show two schematic diagrams in which a multi-link device communicates with other devices through multiple links in a wireless local area network.
  • FIG. 3( a ) shows a scenario in which the AP multi-link device 101 and the STA multi-link device 102 communicate.
  • the AP multilink device 101 includes subordinate AP101-1 and AP101-2
  • the STA multilink device 102 includes subordinate STA102-1 and STA102-2
  • the AP multilink device 101 and the STA multilink device 102 use the chain Lane 1 and Link 2 communicate in parallel.
  • FIG. 3( b ) shows a scenario in which the AP multi-link device 101 communicates with the STA multi-link device 102 , the STA multi-link device 103 and the STA 104 .
  • the AP multilink device 101 includes subordinate AP101-1 to AP101-3
  • the STA multilink device 102 includes subordinate two STA102-1 and STA102-2
  • the STA multilink device 103 includes two subordinate STA103-1 , STA103-2, STA103-3
  • STA104 are single-link devices
  • AP multi-link devices can use link 1 and link 3 to communicate with STA multi-link device 102 respectively, and use link 2 and link 3 to communicate with Multi-link 103 communicates with STA 104 using link 1.
  • STA104 works in the 2.4GHz frequency band
  • the STA multilink device 103 includes STA103-1 and STA103-2, STA103-1 works in the 5GHz frequency band, and STA103-2 works in the 6GHz frequency band
  • the STA multilink device 102 includes STA102 -1 and STA102-2, STA102-1 works in the 2.4GHz band, and STA102-2 works in the 6GHz band.
  • the AP 101-1 operating in the 2.4GHz frequency band in the AP multi-link device can transmit uplink or downlink data between the STA 104 and the STA 102-2 in the STA multi-link device 102 through the link 1.
  • the AP 101-2 operating in the 5GHz frequency band in the AP multi-link device can transmit uplink or downlink data between the STA 103-1 operating in the 5GHz frequency band in the STA multi-link device 103 through link 2.
  • the AP 101-3 operating in the 6GHz frequency band in the AP multi-link device 101 can transmit uplink or downlink data through the link 3 and the STA 102-2 operating in the 6GHz frequency band in the STA multi-link device 102, and can also transmit the uplink or downlink data through the link 3 Uplink or downlink data is transmitted with the STA103-2 in the STA multilink device.
  • Figure 3(a) only shows that the AP multi-link device supports two frequency bands
  • Figure 3(b) only shows that the AP multi-link device supports three frequency bands (2.4GHz, 5GHz, 6GHz).
  • Each frequency band corresponds to one link
  • the AP multi-link device 101 can work on one or more links in link 1, link 2 or link 3 as an example for illustration.
  • the link On the AP side or the STA side, the link here can also be understood as a station working on the link.
  • AP multi-link devices and STA multi-link devices can also support more or less frequency bands, that is, AP multi-link devices and STA multi-link devices can work on more or fewer links.
  • this embodiment of the present application does not limit this.
  • a multi-link device is a device with a wireless communication function, and the device can be an entire device, or a chip or a processing system installed in the entire device, and a device that installs these chips or processing systems.
  • the methods and functions of the embodiments of the present application may be implemented under the control of these chips or processing systems.
  • a multi-link device may support simultaneous transmit and receive (STR) data, or a multi-link device may not support simultaneous transmission and reception of data.
  • supporting the simultaneous sending and receiving of data means that: in the process of sending data on one link, the multi-link device can receive data on another link.
  • Not supporting simultaneous transmission and reception of data means that a multi-link device cannot receive data on another link during the process of sending data on one link.
  • NSTR For multi-link devices that cannot simultaneously transmit and receive (NSTR), due to limited capabilities, when they send signals on one link, they may not be able to receive signals on the other link. If there is a data packet to be received on another link at this time, the NSTR multi-link device may not receive the data packet, resulting in the loss of the data packet.
  • a synchronous multi-link communication method is proposed in the 802.11 protocol. The synchronous multi-link communication method requires that the transmission end times of the PPDUs sent to the NSTR multi-link device on different links are aligned, so as to reduce the probability that the NSTR multi-link device needs to send and receive at the same time.
  • the existing error recovery mechanism is not suitable for the communication scenario where NSTR MLD uses trigger frame. Specifically, when an error related to the trigger frame occurs on a link (for example, the transmission of the trigger frame fails or an error occurs in the TB PPDU triggered by the trigger frame), the existing error recovery mechanism may fail to perform error recovery successfully, or may fail to perform error recovery successfully. After error recovery, the MLD may need to transmit and receive at the same time.
  • the MLD of the transmitting end that does not support STR obtains the TXOP through the RTS-CTS mechanism on link 1 and link 2 respectively. Afterwards, the MLD at the sending end sends trigger frame 10 on link 1 and trigger frame 20 on link 2. During the transmission process, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful. On the link 1, because the MLD at the sending end determines that the transmission of the trigger frame 10 fails, the PIFS error recovery can be performed. However, after PIFS error recovery, the trigger frame 11 sent by the MLD at the sender end on link 1 will collide with the TB PPDU20 being received.
  • the MLD at the transmitting end may not be able to receive the TB PPDU20 normally on the link 2.
  • the MLD at the sending end cannot reply to the BA20 corresponding to the TB PPDU20 on the link 2 either.
  • the BA20 is represented by a dashed box, indicating that it has not been sent.
  • the MLD at the sending end that does not support STR obtains the TXOP on the link 1 and the link 2 through the RTS-CTS mechanism, respectively. Afterwards, the MLD at the sending end sends trigger frame 10 on link 1 and trigger frame 20 on link 2. During the transmission process, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful. After determining that the transmission of the trigger frame 10 fails, the sending end MLD can perform backoff recovery. After the backoff is successful, the sending MLD sends a trigger frame 11 on link 1.
  • the transmission time of the TB PPDU11 triggered by the trigger frame 11 on link 1 conflicts with the transmission time of the trigger frame 21 sent by the transmitter MLD on link 2, which causes the transmitter MLD to need to send and receive at the same time.
  • the present application provides a trigger frame sending method and device.
  • the embodiments of the present application will be described in detail below with reference to the accompanying drawings in the description.
  • a method for sending a trigger frame includes the following steps:
  • the MLD sends the first trigger frame through the first link at the first moment, and sends the second trigger frame through the second link at the first moment.
  • MLD does not support STR on the first link and the second link. In other words, the MLD does not have the STR capability on the first link and the second link.
  • first link and the second link are any two of the multiple links in the MLD configuration, which are not limited.
  • the MLD may communicate with another MLD through the first link and the second link.
  • the MLD communicates with the first device through the first link and communicates with the second device through the second link, the first device and the second device being two independent devices.
  • the MLD may be an AP MLD or a STA MLD.
  • the transmission end moment of the first trigger frame is aligned with the transmission end moment of the second trigger frame. In this way, it is ensured that the MLD adopts a synchronous multi-link communication method, and the probability of simultaneous transmission and reception of the MLD is reduced.
  • the MLD fails to receive the first TB PPDU triggered by the first trigger frame through the first link, and successfully receives the second TB PPDU triggered by the second trigger frame through the second link , the MLD sends the third trigger frame through the first link at the second moment, and sends the fourth trigger frame through the second link at the third moment.
  • the second moment and the third moment are aligned. Moreover, the transmission end time of the third trigger frame is aligned with the transmission end time of the fourth trigger frame.
  • the alignment of the two moments may mean that the two moments are the same, or the deviation value between the two moments is within the deviation range allowed by the 802.11 protocol.
  • the deviation range allowed by the current 802.11 protocol may be [-8 ⁇ s, 8 ⁇ s] or [-4 ⁇ s, 4 ⁇ s].
  • the third trigger frame and the fourth trigger frame are aligned at the transmission start moment and the transmission end moment, the third trigger frame and the fourth trigger frame are expected to be the same in length.
  • the third trigger frame is another trigger frame sent by the MLD after the first trigger frame is sent through the first link.
  • the parameters included in the third trigger frame may be the same as or similar to the parameters included in the first trigger frame. Therefore, the TB PPDU triggered by the third trigger frame is the same as the TB PPDU triggered by the first trigger frame.
  • the third trigger frame may be composed of the first trigger frame and padding.
  • the parameters included in the third trigger frame may be different from the parameters included in the first trigger frame. Therefore, the TB PPDU triggered by the third trigger frame is different from the TB PPDU triggered by the first trigger frame.
  • the third trigger frame and the first trigger frame can be used to trigger the same device to send TB PPDU, or can be used to trigger different devices to send TB PPDU.
  • the MLD fails to receive the first TB PPDU through the first link, including the following two situations:
  • Scenario 1 The MLD determines that the transmission of the first trigger frame fails.
  • an error occurs in the first trigger frame, which is not limited.
  • the MLD determines that the transmission of the first trigger frame fails, which may be specifically implemented as: the MLD does not receive the first TB PPDU within a preset time interval after the transmission end time of the first trigger frame.
  • the physical layer of the MLD sends a signal to confirm the end of the transmission of the first trigger frame to the MAC layer of the MLD (for example, PHY-TXEND.confirm primitive) .
  • the MAC layer of the MLD does not receive a signal (eg, PHY-RXSTART.indication primitive) sent by the physical layer of the MLD to confirm the reception of the first TB PPDU within a preset time interval, the MLD can determine the first chain The transmission of the first trigger frame on the road failed.
  • the above-mentioned preset time interval may be: aSIFSTime+aSlotTime+aRxPHYStart-Delay.
  • aSIFSTime represents the duration of a SIFS
  • aSlotTime represents the duration of a time slot
  • aRxPHYStart-delay represents the delay from the start of the PPDU on the receiving antenna to the PHY-RXSTART.indication primitive.
  • Scenario 2 The MLD determines that the first TB PPDU received was in error.
  • the MLD can determine An error occurred in the first TB PPDU received.
  • FCS frame check sequence
  • the MAC layer of the MLD receives the PHY-RXEND.indication primitive related to the first TB PPDU sent by the physical layer. If the parameter reception error (RXERROR) carried by the PHY-RXEND.indication primitive is a value other than NoError (such as format violation (FormatViolation), carrier loss (CarrierLost), unsupported rate (UnsupportedRate), Filtered, etc.), the MLD can determine that the received first TB PPDU has an error.
  • RXERROR parameter reception error carried by the PHY-RXEND.indication primitive is a value other than NoError (such as format violation (FormatViolation), carrier loss (CarrierLost), unsupported rate (UnsupportedRate), Filtered, etc.)
  • the MLD After the MLD fails to receive the first TB PPDU through the first link, the MLD detects the channel state of the first link after the transmission end time of the BA of the second TB PPDU. In the case that the first link is in an idle state within the first preset time interval after the transmission end moment of the BA of the second TB PPDU, the MLD may transmit the third trigger frame through the first link at the second moment.
  • the start time of detecting the channel state of the first link may be the end time of transmission of the BA of the second TB PPDU or the time after the end of transmission of the BA of the second TB PPDU.
  • the error recovery scheme 1 if the first link is not in the idle state continuously within the first preset time interval after the transmission end time of the BA of the second TB PPDU, it means that the error recovery fails, so that the MLD can The third trigger frame is not sent over the first link at the second instant.
  • a CCA detection method or other detection methods may be used, which is not limited.
  • the MLD in the process of MLD performing channel detection on the first link, if the MLD sends information (such as the BA of the second TB PPDU) on the second link, the first link will be affected by the second link.
  • the interference of the information sent by the link causes the channel detection result on the first link to be in a busy state, and further causes the error recovery failure on the first link. Therefore, different from the PIFS error recovery in the related art, in the error recovery scheme 1, the starting moment of detecting the channel state of the first link is the end moment of the transmission of the BA of the second TB PPDU or the transmission of the BA of the second TB PPDU. The moment after the end moment. In this way, in the process of channel detection of the first link, the BA of the second TB PPDU sent on the second link is prevented from affecting the detection result of the channel state of the first link, so as to ensure the normal execution of error recovery.
  • the current 802.11 protocol defines the time interval between the transmission end time of the BA and the transmission start time of the next trigger frame as SIFS.
  • the time interval between the transmission start time of the fourth trigger frame and the transmission end time of the BA of the second TB PPDU is SIFS, and the SIFS and PIFS are inconsistent, the fourth trigger frame and the third trigger frame may be caused. Cannot send synchronously.
  • the time interval between the transmission start time (that is, the third time) of the fourth trigger frame and the transmission end time of the BA of the second TB PPDU is set as the first preset time interval.
  • the first preset time interval may be PIFS.
  • the error recovery solution 1 can follow the regulations on PIFS error recovery in the prior art.
  • the first preset time interval may be other types of inter-frame intervals.
  • the first preset time interval may be SIFS.
  • FIG. 7 is used to illustrate the above-mentioned error recovery solution 1.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 on link 2.
  • the sender MLD performs channel detection from the time when the transmission of BA20 ends.
  • the MLD at the sending end sends a trigger frame 11 on the link 1 .
  • the sending end MLD sends the trigger frame 21 on the link 2.
  • Trigger frame 11 and trigger frame 21 are aligned. In this way, it is ensured that the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • the TB PPDU10 in FIG. 7 is represented by a dashed-line frame that has not been received, and the dashed-line frame in the subsequent drawings also represents that the content in the frame has not been received, which is described in a unified manner here, and will not be repeated in the following embodiments.
  • FIG. 8 is used to illustrate the above-mentioned error recovery solution 1.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned.
  • the sender MLD successfully receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 after the interval SIFS. Since an error occurs in the TB PPDU10 received by the sender MLD on link 1, the sender MLD performs channel detection from the moment when the transmission of BA20 ends.
  • the MLD at the sending end sends a trigger frame 11 on the link 1 .
  • the sending end MLD sends the trigger frame 21 on the link 2 .
  • Trigger frame 11 and trigger frame 21 are aligned. In this way, it is ensured that the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • Error recovery solution 2 After the MLD fails to receive the first TB PPDU through the first link, the MLD performs a backoff procedure on the first link. When the back-off counter of the first link backs off to 0 before the transmission start time of the BA of the second TB PPDU, the MLD keeps the back-off counter of the first link at 0 until the transmission of the BA of the second TB PPDU is completed. After that, the MLD detects the channel state of the first link from the end of transmission of the BA of the second TB PPDU. In the case that the first link is in an idle state within a second preset time interval after the transmission end moment of the BA of the second TB PPDU, the MLD sends a third trigger frame through the first link at the second moment.
  • the MLD keeps the back-off counter of the first link at 0 until the BA of the second TB PPDU After the transmission is completed, the purpose is to ensure that the third trigger frame on the first link and the fourth trigger frame on the second link can be sent synchronously.
  • the first link will cause the channel detection result to be a busy state due to the influence of the BA of the second TB PPDU. Therefore, MLD suspends the backoff process.
  • the channel state on the first link changes from a busy state to an idle state.
  • the first link needs to remain in an idle state for a period of time (for example, DIFS, EIFS, or AIFS) to continue the back-off process, thereby competing for a channel.
  • the 802.11 protocol defines the time interval between the transmission end time of the BA and the transmission start time of the next trigger frame as SIFS.
  • the second preset time interval is still set to DIFS, EIFS or AIFS, and the time interval between the transmission end time of the second TB PPDU and the transmission start time of the fourth trigger frame is set to SIFS, then As a result, the third trigger frame and the fourth trigger frame cannot be sent synchronously.
  • the embodiment of the present application sets the time interval between the transmission start time (that is, the third time) of the fourth trigger frame and the transmission end time of the BA of the second TB PPDU as the first time. Two preset time intervals.
  • the second preset time interval may be SIFS. In this way, it is not necessary to modify the time interval between the transmission end time of the BA defined by the existing protocol and the transmission start time of the next trigger frame.
  • the second preset time interval may also be other types of inter-frame intervals, which are not limited.
  • the second preset time interval may be PIFS, DIFS, AIFS, or EIFS.
  • Fig. 9 is used to illustrate the above-mentioned error recovery solution 2.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 on link 2.
  • the sender MLD performs a backoff procedure on the link 1. If the backoff counter of link 1 backs off to 0 before the transmission start time of BA20, the MLD at the sending end will keep the backoff counter of link 1 at 0 until the transmission of BA20 is completed.
  • the MLD of the sender After the transmission of BA20 is completed, the MLD of the sender will detect the channel status of link 1. When link 1 is in an idle state and reaches SIFS, the MLD at the transmitting end sends trigger frame 11 on link 1. In addition, the sender MLD sends the trigger frame 21 on the link 2 after SIFS from the transmission end time of the BA20. It can be seen that the trigger frame 11 and the trigger frame 21 can be aligned. In this way, it is ensured that the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • the MLD After the MLD fails to receive the first TB PPDU through the first link, the MLD sends the dummy frame through the first link at the fourth moment, and the fourth moment and the transmission start moment of the BA of the second TB PPDU Aligned, the length of the dummy frame is the same as the length of the BA of the second TB PPDU. After that, the MLD transmits the third trigger frame through the first link at the second moment. The time interval between the second moment and the transmission end moment of the dummy frame is SIFS.
  • the purpose of sending the dummy frame by the MLD is to maintain the TXOP of the MLD on the first link, so as to prevent the TXOP of the first link from being preempted by other devices.
  • the above-mentioned dummy frame may be any type of frame, such as a control frame, a data frame, etc., which is not limited.
  • the transmission start time of the dummy frame (that is, the fourth time) is aligned with the transmission start time of the BA of the second TB PPDU, and the length of the dummy frame is the same as the length of the BA of the second TB PPDU, the transmission of the dummy frame is guaranteed to end.
  • the time is aligned with the transmission end time of the BA of the second TB PPDU.
  • the alignment of the transmission end time of the dummy frame with the transmission end time of the BA of the second TB PPDU may mean that the transmission end time of the dummy frame is the same as the transmission end time of the BA of the second TB PPDU, or the transmission end time of the dummy frame.
  • the deviation value from the transmission end time of the BA of the second TB PPDU is within the deviation range allowed by the 802.11 protocol.
  • the deviation range allowed by the current 802.11 protocol may be [-8 ⁇ s, 8 ⁇ s] or [-4 ⁇ s, 4 ⁇ s].
  • the embodiment of the present application does not limit the time interval between the transmission start time of the second TB PPDU and the transmission end time of the BA of the second TB PPDU.
  • the time interval may have different values in different scenarios.
  • the time interval between the transmission start time of the second TB PPDU and the transmission end time of the BA of the second TB PPDU may be SIFS; or, when an error occurs in the first TB PPDU
  • the time interval between the transmission start time of the second TB PPDU and the transmission end time of the BA of the second TB PPDU may be PIFS.
  • the MLD may use backoff error recovery before sending the dummy frame to determine whether the dummy frame can be sent. For example, after the MLD fails to receive the first TB PPDU over the first link, the MLD performs a backoff procedure on the first link. In the case where the back-off counter of the first link backs off to 0 before the transmission start time of the BA of the second TB PPDU, the MLD keeps the back-off counter of the first link at 0 until the fourth time. After that, the MLD sends the dummy frame through the first link at the fourth moment.
  • FIG. 10 is used to illustrate the above-mentioned error recovery solution 3.
  • the transmitter MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful. After that, the sender MLD receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 on link 2. In the case that the transmission of the trigger frame 10 fails, the MLD at the sending end executes the backoff procedure on the link 1.
  • the MLD at the transmitting end keeps the count value of the backoff counter of link 1 at 0 until the fourth time is reached.
  • the sending end MLD sends trigger frame 11 through link 1 after the SIFS from the transmission end time of the dummy frame, and sends trigger frame 21 through link 1 after SIFS from the BA20 transmission end time. In this way, it is ensured that the trigger frame 11 and the trigger frame 21 are aligned, and the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • the MLD may employ PIFS error recovery before sending the dummy frame to determine whether the dummy frame can be sent. For example, after the MLD fails to receive the first TB PPDU over the first link, the MLD may perform channel detection on the first link. In the case where the MLD determines that the first link is in an idle state within the PIFS before the transmission start time of the BA of the second TB PPDU, the MLD transmits the dummy frame through the first link at the fourth time.
  • Fig. 11 is used to illustrate the above-mentioned error recovery solution 3.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 on link 2.
  • the MLD at the transmitting end detects the channel state of the link 1 . If the link 1 remains in an idle state in the PIFS before the transmission start time of the BA20, the sending end MLD sends the dummy frame through the link 1 at the fourth time.
  • the sender MLD sends trigger frame 11 through link 1 after the SIFS from the transmission end time of the dummy frame, and sends trigger frame 21 through link 1 after SIFS from the BA20 transmission end time. In this way, it is ensured that the trigger frame 11 and the trigger frame 21 are aligned, and the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • the embodiment of the present application may
  • the time interval between the transmission start time of the BA and the transmission end time of the second TB PPDU is modified from SIFS to PIFS + offset value. In this way, on the one hand, it is ensured that the MLD has enough time to complete error recovery on link 1 after the end of the transmission of the first TB PPDU; The transfer start time is aligned.
  • the deviation value may be a positive number or a negative number, which is not limited.
  • the value range of the deviation value can be [-8 ⁇ s, 8 ⁇ s] or [-4 ⁇ s, 4 ⁇ s].
  • the deviation value may be 8 ⁇ s, 4 ⁇ s, -4 ⁇ s, -8 ⁇ s, and the like.
  • Fig. 12 is used to illustrate the above-mentioned error recovery solution 3.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned.
  • the sender MLD receives the TB PPDU20 on link 2, and replies to the BA20 of the TB PPDU20 on link 2.
  • the sender MLD receives TB PPDU10 on link 1, but TB PPDU10 has an error. Therefore, the sender MLD performs a backoff procedure on link 1. If the back-off counter of link 1 backs off to 0 before the fourth time, the MLD at the sending end keeps the count value of the back-off counter at 0 until the fourth time arrives.
  • the MLD at the sending end sends the dummy frame through link 1 at the fourth moment.
  • the sender MLD sends trigger frame 11 through link 1 after SIFS from the end time of dummy frame transmission, and sends trigger frame 21 through link 1 after SIFS from the end time of BA20 transmission. In this way, it is ensured that the trigger frame 11 and the trigger frame 21 are aligned, and the subsequent TB PPDU11 and TB PPDU21 are aligned, and BA11 and BA21 are aligned.
  • the MLD sends the third trigger frame through the first link at the second moment, and sends the fourth trigger frame through the second link at the third moment. It can be seen that when an error related to the first trigger frame occurs on the first link, the MLD can also send the next trigger frame (that is, the third trigger frame) on the first link, so as to realize the Error recovery. In addition, since the second moment and the third moment are aligned, the third trigger frame and the fourth trigger frame are sent synchronously, so as to reduce the probability that the MLD needs to send and receive data at the same time, and ensure that the MLD can communicate normally.
  • a method for sending a trigger frame includes the following steps:
  • the MLD sends the first trigger frame through the first link at the first moment, and sends the second trigger frame through the second link at the first moment.
  • step S201 reference may be made to the relevant description of step S101 in the embodiment shown in FIG. 6, and details are not repeated here.
  • the second time is located after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU. It should be understood that the second time may be the end time of transmission of the second TB PPDU, or the start time of transmission of the BA of the second TB PPDU, or the end time of the transmission of the second TB PPDU to the start time of the transmission of the BA of the second TB PPDU any moment in the time period in between.
  • the second time is located after the transmission end time of the second TB PPDU.
  • the reason is to avoid the simultaneous occurrence of the MLD receiving the second TB PPDU and the MLD sending the third trigger frame, that is, to avoid the situation that the MLD needs to send and receive at the same time, and to ensure that the MLD can operate normally. communication.
  • the second time is located before the transmission start time of the BA of the second TB PPDU.
  • the reason is that since the MLD does not support STR, the BA sending the second TB PPDU on the second link will cause the channel detection result on the first link to be changed. become busy, which in turn interferes with normal error recovery on the first link. Therefore, the error recovery on the first link can be prevented from being affected by the BA of the second TB PPDU by having the MLD complete the error recovery before the second time instant.
  • Error recovery scheme 4 After the MLD determines that the received first TB PPDU triggered by the first trigger frame has an error, the MLD performs channel detection on the first link. In the case that the first link is in an idle state within the PIFS before the second time, the MLD transmits the third trigger frame through the first link at the second time.
  • Fig. 14 is used to illustrate the error recovery scheme 4.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the MLD at the transmitting end receives TB PPDU20 on link 2, and replies to BA20 of TB PPDU20 on link 2.
  • the sender MLD detects the channel state of link 1; if link 1 is idle in the PIFS before the transmission start time of BA20, the sender MLD transmits trigger frame 11 from the transmission start time of BA20.
  • the transmission end time of the trigger frame 11 is aligned with the transmission end time of the trigger frame 21 .
  • Fig. 15 is used to illustrate the error recovery scheme 4.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives TB PPDU20 on link 2, and replies with BA20 of TB PPDU20 on link 2.
  • the sending end MLD detects the channel state of link 1; if link 1 is in an idle state in the PIFS before the transmission end time of TB PPDU20, the sending end MLD transmits trigger frame 11 from the end time of TB PPDU20 transmission.
  • the transmission end time of the trigger frame 11 is aligned with the transmission end time of the trigger frame 21 .
  • the MLD may not send the third trigger through the first link at the second moment. frame.
  • Error recovery solution 5 After the MLD determines that the received first TB PPDU triggered by the first trigger frame has an error, the MLD performs a backoff procedure on the first link. In the case where the back-off counter of the first link backs off to 0 before the second time, the MLD keeps the back-off counter of the first link at 0 until the second time. After that, the MLD transmits the third trigger frame through the first link at the second moment.
  • Fig. 16 is used to illustrate the error recovery scheme 4.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives TB PPDU20 on link 2, and replies with BA20 of TB PPDU20 on link 2.
  • the sender MLD performs a backoff procedure on link 1. If the backoff counter of link 1 backs off to 0 before the transmission start time of BA20, the sending end MLD keeps the backoff counter of link 1 at 0 until the transmission start time of BA20. After that, the sending end MLD sends the trigger frame 11 through the link 1 at the transmission start time of the BA20.
  • the transmission end time of the trigger frame 11 is aligned with the transmission end time of the trigger frame 21 .
  • Fig. 17 is used to illustrate the error recovery scheme 4.
  • the sending end MLD sends trigger frame 10 on link 1 and trigger frame 20 on link 2, and trigger frame 10 and trigger frame 20 are aligned. Wherein, the transmission of trigger frame 10 fails, and the transmission of trigger frame 20 is successful.
  • the sender MLD receives TB PPDU20 on link 2, and replies with BA20 of TB PPDU20 on link 2.
  • the sender MLD performs a backoff procedure on link 1. If the backoff counter of link 1 backs off to 0 before the transmission end time of TB PPDU20, the sending end MLD keeps the backoff counter of link 1 at 0 until the transmission end time of TB PPDU20. After that, the sending end MLD sends the trigger frame 11 through the link 1 at the time when the transmission of the TB PPDU20 ends.
  • the transmission end time of the trigger frame 11 is aligned with the transmission end time of the trigger frame 21 .
  • the MLD can reply to the BA of the second TB PPDU through the second link. After that, the MLD may also send a fourth trigger frame through the second link at the third moment.
  • the third time is later than the second time.
  • the time interval between the third moment and the end moment of transmission of the BA of the second TB PPDU is SIFS.
  • the transmission end time of the fourth trigger frame is aligned with the transmission end time of the third trigger frame, so as to ensure that the MLD uses the synchronous link communication mode and reduce the probability that the MLD needs to transmit and receive at the same time.
  • the alignment of the third moment and the fourth moment may mean that the third moment and the fourth moment are the same, or the deviation value between the third moment and the fourth moment is within the deviation range allowed by the 802.11 protocol.
  • the deviation range allowed by the current 802.11 protocol may be [-8 ⁇ s, 8 ⁇ s] or [-4 ⁇ s, 4 ⁇ s].
  • the MLD sends the third trigger frame through the first link at the second moment. It can be seen that when an error related to the first trigger frame occurs on the first link, the MLD can also send the next trigger frame (that is, the third trigger frame) on the first link, so as to realize the Error recovery.
  • the second time is located after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU, so as to avoid the adverse effect of the BA of the second TB PPDU on the error recovery on the first link,
  • the error recovery of the first link can be performed normally.
  • the MLD since the MLD does not need to receive data on the second link during the period after the transmission end time of the second TB PPDU and before the transmission start time of the BA of the second TB PPDU, the MLD does not need to receive data during this period.
  • Sending the third trigger frame can reduce the probability that the MLD needs to send and receive data at the same time, and ensure that the MLD can communicate normally.
  • BA may be understood as a reply frame.
  • the reply frame may also include an acknowledgement (ACK). Therefore, BA in this application can also be replaced by ACK. That is to say, the BA in this application only means a reply frame, and the reply frame does not necessarily have to be a BA, but can also be an ACK.
  • the PPDUs sent by the STR MLD on different links may also be required to be aligned at the sending time.
  • the PPDU sent by the STR MLD may be an uplink (uplink, UL) PPDU or a downlink (downlink, DL) PPDU.
  • the alignment of the transmission times of the two PPDUs may mean that the transmission times of the two PPDUs are the same, or the deviation value between the transmission times of the two PPDUs is within the deviation range allowed by the 802.11 protocol.
  • the deviation range allowed by the current 802.11 protocol may be [-8 ⁇ s, 8 ⁇ s] or [-4 ⁇ s, 4 ⁇ s].
  • the MLD includes corresponding hardware structures and/or software modules for executing each function.
  • the present application can be implemented in hardware or a combination of hardware and computer software with the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein. Whether a function is performed by hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.
  • the device may be divided into functional modules according to the foregoing method examples.
  • each functional module may be divided corresponding to each function, or two or more functions may be integrated into one functional module.
  • the above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules.
  • the division of modules in the embodiments of the present application is schematic, and is only a logical function division, and there may be other division manners in actual implementation. The following is an example of dividing each function module corresponding to each function to illustrate:
  • a communication device provided by an embodiment of the present application includes: a processing module 101 and a communication module 102 .
  • the communication module 102 performs steps S101 and S102 in FIG. 6 , as well as other communication operations (for example, sending BA) in this embodiment of the present application.
  • the processing module 101 is configured to control the communication module to perform step S102 in FIG. 6 and other processing operations in the embodiments of the present application (for example, detecting the channel state of the first link).
  • the communication module 102 performs steps S201 and S202 in FIG. 13 , and other communication operations (for example, sending BA) in this embodiment of the present application.
  • the processing module 101 is configured to control the communication module to perform steps S201 and S202 in FIG. 13 , as well as other processing operations in this embodiment of the present application (for example, detecting the channel state of the first link).
  • the above-mentioned processing module 101 may include at least two processing sub-modules, and each processing sub-module may be responsible for processing operations on one link.
  • the above-mentioned communication module 102 may include at least two communication sub-modules, and each communication sub-module may be responsible for communication operations on one link.
  • FIG. 19 is a structural diagram of a possible product form of the communication device according to the embodiment of the present application.
  • the communication device described in this embodiment of the present application may be an MLD, and the MLD includes a processor 201 and a transceiver 202 .
  • the transceiver 202 performs steps S101 and S102 in FIG. 6 , and other communication operations (for example, sending BA) in this embodiment of the present application.
  • the processor 201 is configured to control the communication module to perform step S102 in FIG. 6 and other processing operations in this embodiment of the present application (for example, detecting the channel state of the first link).
  • the transceiver 202 performs steps S201 and S202 in FIG. 13 , and other communication operations (for example, sending BA) in this embodiment of the present application.
  • the processor 201 is configured to control the communication module to perform steps S201 and S202 in FIG. 13 , as well as other processing operations (for example, detecting the channel state of the first link) in this embodiment of the present application.
  • the communication device described in the embodiments of the present application may also be implemented by a chip.
  • the chip includes: a processing circuit 201 and a transceiver pin 202 .
  • the chip may further include a storage medium 203 .
  • the communication apparatus described in the embodiments of the present application may also be implemented by using the following circuits or devices: one or more field programmable gate arrays (FPGA), programmable logic A programmable logic device (PLD), controller, state machine, gate logic, discrete hardware components, any other suitable circuit, or any combination of circuits capable of performing the various functions described throughout this application.
  • FPGA field programmable gate arrays
  • PLD programmable logic A programmable logic device
  • state machine gate logic
  • discrete hardware components any other suitable circuit, or any combination of circuits capable of performing the various functions described throughout this application.
  • an embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a computer, causes the computer to execute the communication methods in the foregoing method embodiments. .
  • the embodiment of the present application further provides a computer program product including computer instructions, when the computer instructions are executed on the computer, the computer can execute the communication method in the foregoing method embodiments.
  • the computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server Or the data center transmits to another website site, computer, server or data center by wire (eg coaxial cable, optical fiber, digital subscriber line) or wireless (eg infrared, wireless, microwave, etc.).
  • the computer-readable storage medium can be any available medium that can be accessed by a computer or data storage devices including one or more servers, data centers, etc. that can be integrated with the medium.
  • the usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media, or semiconductor media (eg, solid state drives), and the like.
  • the apparatuses and methods disclosed in the several embodiments provided in this application may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be Incorporation may either be integrated into another device, or some features may be omitted, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place, or may be distributed to multiple different places . Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a readable storage medium.
  • the technical solutions of the embodiments of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, which are stored in a storage medium , including several instructions to make a device (may be a single chip microcomputer, a chip, etc.) or a processor (processor) to execute all or part of the steps of the methods described in the various embodiments of the present application.

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Abstract

一种触发帧发送方法及装置，涉及无线通信技术领域(例如WLAN)，用于在NSTR MLD通信的场景下，实现与触发帧相关的错误恢复。该方法包括：MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻对齐。之后，在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，以及通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧，在第三时刻通过第二链路发送第四触发帧，第二时刻与第三时刻对齐。

Description

触发帧发送方法及装置
本申请要求于2020年12月11日提交国家知识产权局、申请号为202011460426.7、申请名称为“触发帧发送方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及无线通信技术领域，尤其涉及触发帧发送方法及装置。
背景技术
为了达到极高吞吐率的技术目标，电气和电子工程师协会(institute of electrical and electronics engineers，IEEE)802.11be标准将多链路(multi-link，ML)通信作为关键技术之一。支持ML通信的多链路设备(multi-link device，MLD)具有在多个链路发送和接收的能力，从而MLD可以利用更大的带宽进行数据传输，有利于显著提升吞吐率。其中，一个链路可以指MLD在一个频段上进行数据传输的空间路径。
根据MLD是否具备在不同链路上同时收发(simultaneous transmitting and receiving，STR)的能力，可以将MLD分为STR MLD和non-STR MLD。STR MLD具备STR能力，non-STR MLD不具备STR能力。
对于有non-STR MLD参与通信的场景，链路的错误恢复为其中的重要部分。但是，目前，业界尚未提出与触发帧相关的错误恢复机制。
发明内容
本申请实施例提供一种触发帧发送方法及装置，在non-STR MLD通信的场景下，实现与触发帧相关的错误恢复。
第一方面，提供一种触发帧发送方法，该方法包括：多链路设备MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻对齐；在MLD通过第一链路未成功接收到由第一触发帧所触发的第一基于触发帧的物理层协议数据单元(trigger-based PHY protocol data unit，TB PPDU)，以及通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧，以及在第三时刻通过第二链路发送第四触发帧，第二时刻和第三时刻对齐。
基于上述技术方案，在第一链路上未成功接收到由第一触发帧所触发的第一TB PPDU，而在第二链路上成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧，在第三时刻通过第二链路发送第四触发帧。可见，在第一链路上出现与第一触发帧相关的错误时，MLD还可以在第一链路上发送下一个触发帧(也即第三触发帧)，从而实现第一链路上的错误恢复。另外，由于第二时刻和第三时刻对齐，因此第三触发帧和第四触发帧是同步发送的，以降低MLD需要同时收发数据的情况发生的概率，保证MLD能够正常通信。
一种可能的设计中，在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，方法还包括：MLD在第二TB PPDU的块确认(block ack，BA)的传输结束时刻之后检测第一链路的信道状态。
一种可能的设计中，MLD在第二时刻通过第一链路发送第三触发帧，包括：在第一链路在第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内处于空闲状态的情况下，MLD在第二时刻通过第一链路发送第三触发帧。基于该设计，可以避免MLD在第一链路上传输的信息与其他设备在第一链路传输的信息发生冲突。
一种可能的设计中，第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第一预设时间间隔。
一种可能的设计中，第一预设时间间隔为点协调功能帧间间隔(point coordination function interframe space，PIFS)。这样一来，将第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔从相关技术定义的SIFS修改为PIFS，可以保证第三时刻与第二时刻对齐，从而保证MLD在第一链路和第二链路上能够同步发送。
一种可能的设计中，在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，方法还包括：MLD在第一链路上执行退避流程；在第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，MLD将第一链路的退避计数器保持为0，直至第二TB PPDU的BA传输完毕；MLD在第二TB PPDU的BA的传输结束时刻起检测第一链路的信道状态。
一种可能的设计中，MLD在第二时刻通过第一链路发送第三触发帧，包括：在第一链路在第二TB PPDU的BA的传输结束时刻之后的第二预设时间间隔内处于空闲状态的情况下，MLD在第二时刻通过第一链路发送第三触发帧。
一种可能的设计中，第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第二预设时间间隔。
一种可能的设计中，第二预设时间间隔为短帧间间隔(short interframe space，SIFS)。基于该设计，相当于将退避流程在从繁忙切换到空闲后需要等待的时间从相关技术中定义的AIFS修改为SIFS，从而保证第二时刻与第三时刻能够对齐，进而保证MLD在第一链路和第二链路上能够同步发送。
一种可能的设计中，在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，方法还包括：MLD在第四时刻通过第一链路发送虚设(dummy)帧，第四时刻第二TB PPDU的BA的传输开始时刻对齐，dummy帧的长度与第二TB PPDU的BA的长度相同。基于该设计，通过发送dummy帧来维持MLD在第一链路上的TXOP，从而使得MLD可以在第一链路上发送下一个触发帧。
一种可能的设计中，在MLD在第四时刻通过第一链路发送dummy帧之前，方法还包括：MLD确定在第四时刻之前的PIFS内第一链路处于空闲状态。
一种可能的设计中，在MLD第四时刻通过第一链路发送dummy帧之前，方法还包括：MLD在第一链路上执行退避流程；当第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0时，MLD将第一链路的退避计数器保持为0，直至第四时刻。
一种可能的设计中，MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，包括：MLD确定第一触发帧传输失败。
一种可能的设计中，MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，包括：MLD确定接收到的第一TB PPDU发生错误。
第二方面，提供一种触发帧发送方法，该方法包括：多链路设备MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻对齐；在第一触发帧传输失败，以及MLD通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧；第二时刻位于在第二TB PPDU的传输结束时刻之后，在第二TB PPDU的BA的传输开始时刻之前。
基于上述技术方案，在第一触发帧所触发的第一TB PPDU发生错误，而在第二链路上成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧。可见，在第一链路上出现与第一触发帧相关的错误时，MLD还可以在第一链路上发送下一个触发帧(也即第三触发帧)，从而实现第一链路上的错误恢复。另外，第二时刻位于第二TB PPDU的传输结束时刻之后，第二TB PPDU的BA的传输开始时刻之前，以避免第二TB PPDU的BA对第一链路上的错误恢复造成的不利影响，使得第一链路的错误恢复能够正常进行。并且，由于第二TB PPDU的传输结束时刻之后，第二TB PPDU的BA的传输开始时刻之前的这段时间内，MLD不需要在第二链路上接收数据，因此，MLD在这段时间内发送第三触发帧，可以降低MLD需要同时收发数据的情况发生的概率，保证MLD能够正常通信。
一种可能的设计中，在MLD确定第一触发帧传输失败之后，方法还包括：MLD确定在第二时刻之前的PIFS内第一链路处于空闲状态。
一种可能的设计中，在MLD确定第一触发帧传输失败之后，方法还包括：MLD在第一链路上执行退避流程；当第一链路的退避计数器在第二时刻之前退避到0时，MLD将第一链路的退避计数器保持为0，直至第二时刻。
一种可能的设计中，第二时刻与第二TB PPDU的BA的传输开始时刻对齐。或者，第二时刻与第二TB PPDU的传输结束时刻对齐。
第三方面，提供一种MLD，包括：处理模块和与处理模块连接的通信模块。通信模块，用于在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻对齐。处理模块，还用于在MLD通过第一链路未成功接收到由第一触发帧所触发的第一基于触发帧的物理层协议数据单元TB PPDU，以及通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，控制通信模块在第二时刻通过第一链路发送第三触发帧，以及在第三时刻通过第二链路发送第四触发帧，第二时刻和第三时刻对齐。
一种可能的设计中，处理模块，还用于在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，在第二TB PPDU的块确认BA的传输结束时刻之后检测第一链路的信道状态。
一种可能的设计中，通信模块，用于在第一链路在第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内处于空闲状态的情况下，在第二时刻通过第一链路发送第三触发帧。
一种可能的设计中，第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第一预设时间间隔。
一种可能的设计中，第一预设时间间隔为PIFS。
一种可能的设计中，处理模块，还用于在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，在第一链路上执行退避流程；在第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，将第一链路的退避计数器保持为0，直至第二TB PPDU的BA传输完毕；在第二TB PPDU的BA的传输结束时刻起检测第一链路的信道状态。
一种可能的设计中，通信模块，用于在第一链路在第二TB PPDU的BA的传输结束时刻之后的第二预设时间间隔内处于空闲状态的情况下，在第二时刻通过第一链路发送第三触发帧。
一种可能的设计中，第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第二预设时间间隔。
一种可能的设计中，第二预设时间间隔为SIFS。
一种可能的设计中，通信模块，还用于在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU之后，在第四时刻通过第一链路发送dummy帧，第四时刻第二TB PPDU的BA的传输开始时刻对齐，dummy帧的长度与第二TB PPDU的BA的长度相同。
一种可能的设计中，处理模块，还用于在通信模块在第四时刻通过第一链路发送dummy帧之前，确定在第四时刻之前的PIFS内第一链路处于空闲状态。
一种可能的设计中，处理模块，还用于在第一链路上执行退避流程；当第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0时，将第一链路的退避计数器保持为0，直至第四时刻。
一种可能的设计中，MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，包括：MLD确定第一触发帧传输失败。
一种可能的设计中，MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，包括：MLD确定接收到的第一TB PPDU发生错误。
第四方面，提供一种通信装置，包括：处理模块和与处理模块连接的通信模块。通信模块，用于在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻对齐。处理模块，还用于在第一触发帧传输失败，以及MLD通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，控制通信模块在第二时刻通过第一链路发送第三触发帧；第二时刻位于在第二TB PPDU的传输结束时刻之后，在第二TB PPDU的BA的传输开始时刻之前。
一种可能的设计中，处理模块，还用于在确定第一触发帧传输失败之后，确定在第二时刻之前的PIFS内第一链路处于空闲状态。
一种可能的设计中，处理模块，还用于在确定第一触发帧传输失败之后，在第一链路上执行退避流程；当第一链路的退避计数器在第二时刻之前退避到0时，将第一链路的退避计数器保持为0，直至第二时刻。
一种可能的设计中，第二时刻与第二TB PPDU的BA的传输开始时刻对齐。或者，第二时刻与第二TB PPDU的传输结束时刻对齐。
第五方面，提供一种通信装置，所述通信装置包括处理器和收发器，处理器和收发 器用于实现上述第一方面或者第二方面中任一设计提供的方法。其中，处理器用于执行相应方法中的处理动作，收发器用于执行相应方法中的接收/发送的动作。
第六方面，提供一种计算机可读存储介质，所述计算机可读存储介质存储计算机指令，当该计算机指令在计算机上运行时，使得计算机执行第一方面或者第二方面中任一设计提供的方法。
第七方面，提供一种包含计算机指令的计算机程序产品，当该计算机指令在计算机上运行时，使得计算机执行第一方面或第二方面中任一设计提供的方法。
第八方面，提供一种芯片，包括：处理电路和收发管脚，处理电路和收发管脚用于实现上述第一方面或第二方面中任一设计提供的方法。其中，处理电路用于执行相应方法中的处理动作，收发管脚用于执行相应方法中的接收/发送的动作。
需要说明的是，上述第三方面至第八方面中任一种设计所带来的技术效果可以参见第一方面或第二方面中对应设计所带来的技术效果，此处不再赘述。
附图说明
图1为相关技术中退避流程的示意图；
图2为本申请实施例提供的一种AP多链路设备与STA多链路设备的通信场景示意图；
图3(a)和图3(b)为参与通信的AP多链路设备和STA多链路设备的结构示意图；
图4为相关技术中PIFS错误恢复机制应用于触发帧出错场景的示意图；
图5为相关技术中退避错误恢复机制应用于触发帧出错场景的示意图；
图6为本申请实施例提供的一种触发帧发送方法的流程图；
图7为本申请实施例提供的另一种触发帧发送的场景示意图；
图8为本申请实施例提供的另一种触发帧发送的场景示意图；
图9为本申请实施例提供的另一种触发帧发送的场景示意图；
图10为本申请实施例提供的另一种触发帧发送的场景示意图；
图11为本申请实施例提供的另一种触发帧发送的场景示意图；
图12为本申请实施例提供的另一种触发帧发送的场景示意图；
图13为本申请实施例提供的另一种触发帧发送方法的流程图；
图14为本申请实施例提供的另一种触发帧发送的场景示意图；
图15为本申请实施例提供的另一种触发帧发送的场景示意图；
图16为本申请实施例提供的另一种触发帧发送的场景示意图；
图17为本申请实施例提供的另一种触发帧发送的场景示意图；
图18为本申请实施例提供的一种通信装置的结构示意图；
图19为本申请实施例提供的另一种通信装置的结构示意图。
具体实施方式
在本申请的描述中，除非另有说明，“/”表示“或”的意思，例如，A/B可以表示A或B。本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。此外，“至少一个”是指一个或多个，“多个”是指两个或两个以上。“第一”、“第二”等字样并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并 不限定一定不同。
本申请中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其他实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。
本申请提供的技术方案可以应用于各种通信系统，例如采用IEEE 802.11标准的系统。示例性的，IEEE 802.11标准包括但不限于：802.11be标准、或者更下一代的802.11标准。本申请的技术方案适用的场景包括：AP与STA之间的通信、AP与AP之间的通信、以及STA与STA之间的通信等。
本申请涉及到的STA可以是各种具有无线通信功能的用户终端、用户装置，接入装置，订户站，订户单元，移动站，用户代理，用户装备或其他名称，其中，用户终端可以包括各种具有无线通信功能的手持设备、车载设备、可穿戴设备、计算设备或连接到无线调制解调器的其它处理设备，以及各种形式的用户设备(user equipment，UE)，移动台(mobile station，MS)，终端(terminal)，终端设备(terminal equipment)，便携式通信设备，手持机，便携式计算设备，娱乐设备，游戏设备或系统，全球定位系统设备或被配置为经由无线介质进行网络通信的任何其他合适的设备等。在此，为了描述方便，上面提到的设备统称为站点或STA。
本申请所涉及到的接入点AP是一种部署在无线通信网络中为其关联的STA提供无线通信功能的装置，该接入点AP可用作该通信系统的中枢，可以为基站、路由器、网关、中继器，通信服务器，交换机或网桥等通信设备，其中，所述基站可以包括各种形式的宏基站，微基站，中继站等。在此，为了描述方便，上面提到的设备统称为接入点AP。
下面对本申请实施例涉及的术语进行介绍，以便于本领域技术人员理解。
1、传输机会(transmission opportunity，TXOP)
TXOP是无线信道接入的基本单元。TXOP由初始时间和最大持续时间(TXOP limit)组成。获得TXOP的站点在TXOP limit时间内可以不再重新竞争信道、连续使用信道传输多个数据帧。
TXOP可以经由竞争或者混合协调器(hybrid coordinator，HC)分配两种方式获得。其中，经由竞争获得的TXOP可以被称为增强的分布式信道访问(enhanced distributed channel access，EDCA)TXOP。经由HC分配获得的TXOP可以被称为混合式协调功能控制信道访问(hybrid coordination function controlled channel access，HCCA)TXOP。
应理解，本申请不涉及TXOP的获取，TXOP的获取方式的具体细节可以参考现有技术。
2、帧间间隔(interframe space，IFS)
为了尽量避免碰撞，802.11协议规定，设备在完成发送后，必须再等待一段很短的时间才能发送下一帧。这段时间的即是帧间间隔。帧间间隔的长短取决于设备要发送的帧的类型。高优先级的帧需要等待的时间较短，因此可以优先获得发送权，但低优先级帧就必须等待较长的时间。
帧间间隔提供对无线介质访问的不同优先级来进行划分的，不同优先级按照帧间间 隔的时间长短来进行划分。帧间间隔的时间越短，表示其对应的优先级越高，帧间间隔的时间从小到大排列如下：
(1)短帧间间隔(short interframe space，SIFS)
(2)点协调功能帧间间隔(point coordination function interframe space，PIFS)
(3)分布协调功能帧间间隔(distributed coordination function interframe space，DIFS)
(4)仲裁帧间间隔(arbitration interframe space，AIFS)
(5)扩展帧间间隔(extended interframe space，EIFS)
3、错误恢复(error recovery)
相关技术中，在TXOP建立成功之后，TXOP内的某个PPDU传输失败时，触发该链路的错误恢复。
其中，错误恢复包括PIFS错误恢复和退避(back off)错误恢复，下面分别进行介绍。
(1)PIFS错误恢复：信道空闲的时长达到PIFS后，设备在该信道上发送下一个PPDU。
(2)退避错误恢复：进行信道退避，在退避结束之后发送下一个PPDU。
4、载波侦听机制
载波侦听机制可以分为物理载波侦听机制和虚拟载波侦听机制。
(1)物理载波侦听机制又被称为空闲信道评估(clear channel assessment，CCA)。在无线通信系统中，当目标设备需要在某一信道上发送数据之前，目标设备首先在这个信道上进行接收。如果经过给定的时间，目标设备没有发现其他设备在此信道上发送数据，则目标设备开始发送数据；如果发现有其他设备在发送数据，则目标设备随机避让一段时间后再次重试此过程。
空闲信道评估包括包检测和能量检测。其中，包检测是检测信道上是否有数据包传输(可通过检测是否有包头来判断是否有数据包传输)，如果信道上存在数据包且能量超过一个包检测阈值，则认为信道繁忙。能量检测是检测信道上的能量大小，如果信道上的能量大于或等于能量检测阈值，则认为信道繁忙。当包检测的结果和能量检测的结果均为信道空闲时，才认为该信道是空闲状态。换句话说，如果在某段时间内没有检测到包头，且能量检测时信道上的能量小于该能量检测阈值，则认为该信道是空闲状态。
(2)虚拟载波侦听机制使用在802.11帧中所发现的信息来预测无线介质的状态。通常，虚拟载波侦听是由NAV所提供。一个设备可以维护一个或多个NAV。NAV本身为一个定时器，通过使用帧的MAC报头中的持续时间值来进行设置。NAV的值会随着时间推移不断减少。NAV不为零，表示无线介质处于繁忙状态。NAV为零，表示无线介质处于空闲状态。上述无线介质可以为信道、频段等。
其中，NAV通过使用帧的MAC报头中的持续时间值来进行设置，可以具体实现为：当一个站点接收到一个帧后，如果该帧的接收地址不是该站点且该帧中duration字段的数值大于站点当前的NAV数值，则该站点可以根据接收到的帧中的持续时间(duration)字段来更新NAV。如果该帧的接收地址是该站点，说明该站点为接收站点，或该帧中duration字段的数值小于或等于站点当前的NAV数值，则不可以更新NAV。其中，NAV数值从接收到的无线帧的结束时刻开始算起的。
5、退避机制
IEEE 802.11标准支持多个用户共享同一传输介质，由发送者在发送数据前先进行传输介质的可用性检测。IEEE 802.11标准采用载波侦听多路访问/碰撞避免(carrier sense multiple access with collision avoidance，CSMA/CA)来实现信道的竞争。其中，为了避免碰撞，CSMA/CA采用了退避机制。
下面对单信道上的退避机制进行说明。在设备发送消息之前，设备可以从0到竞争窗口(contention window，CW)之间选择一个随机数，并以该随机数作为退避计数器的初始值。在信道的空闲时间达到仲裁帧间间隔(arbitration inter-frame space，AIFS)之后，当信道每空闲一个时隙(timeslot)时，退避计数器的计数值减1。在退避计数器的计数值减为0之前，若信道在某一个timeslot的状态为繁忙，则退避计数器暂停计数。之后，若信道从繁忙状态转为空闲状态后，并且信道的空闲时间达到AIFS之后，退避计数器恢复计数。当退避计数器的计数值为0时，退避流程结束，设备可以开始数据传输。
结合图1进行举例说明，假设退避计数器的初始值为5，在信道的空闲时间达到AIFS后，退避计数器开始回退。每当信道在一个时隙中处于空闲状态，退避计数器的计数值减1，直至退避计数器的计数值为0。在退避计数器的计数值为0后，设备成功竞争到信道，设备可以在该信道上发送PPDU。
以上是对本申请实施例所涉及的技术术语的介绍，以下不再赘述。
目前IEEE 802.11下一代无线保真(wireless fidelity，WiFi)协议极高吞吐量(extremely high throughput，EHT)设备支持通过多个流数、多个频段(例如，2.4GHz，5GHz和6GHz频段)，以及同一频段上通过多个信道的合作等方式提高峰值吞吐量，降低业务传输的时延。该多频段或多信道可以统称为多链路。
多链路设备包括一个或多个隶属的站点，隶属的站点可以是逻辑上的站点，也可以是物理上的站点。在本申请实施例中，“多链路设备包括隶属的站点”可以简要描述为“多链路设备包括站点”。
其中，隶属的站点可以为接入点(access point，AP)或者非接入点站点(non-access point station，non-AP STA)。为描述方便，本申请实施例可以将隶属的站点为AP的多链路设备称为多链路AP，或者AP MLD，或者多链路AP设备；可以将隶属的站点为STA的多链路设备称为多链路STA，或者多链路STA设备，或者STA MLD，或者non-AP MLD。
多链路设备可以遵循802.11协议实现无线通信。示例性的，802.11协议可以为802.11ax协议、802.11be协议、以及下一代802.11协议，本申请实施例不限于此。
多链路设备可以与其他设备通信。本申请实施例中，其他设备可以是多链路设备，也可以不是多链路设备。
示例性的，图2为AP多链路设备与STA多链路设备的通信场景示意图。如图2所示，一个AP多链路设备可以关联多个STA多链路设备以及单链路STA。例如，AP多链路设备100关联STA多链路设备200、STA多链路设备300、以及STA400。应理解，AP多链路设备中的多个AP分别工作在多个链路上，STA多链路设备中的多个STA分别工作在多个链路上，STA多链路设备中的一个STA关联其工作链路上AP多链路设备中的一个AP。单链路STA关联其工作链路上AP多链路设备中的一个AP。
多链路设备工作的频段可以包括但不限于：sub 1GHz，2.4GHz，5GHz，6GHz以及 高频60GHz。图3(a)、图3(b)示出了无线局域网中多链路设备与其他设备通过多条链路进行通信的两种示意图。
图3(a)示出了一种AP多链路设备101和STA多链路设备102通信的场景。AP多链路设备101包括隶属的AP101-1和AP101-2，STA多链路设备102包括隶属的STA102-1和STA102-2，且AP多链路设备101和STA多链路设备102采用链路1和链路2并行进行通信。
图3(b)示出了AP多链路设备101与STA多链路设备102，STA多链路设备103以及STA104进行通信的场景。AP多链路设备101包括隶属的AP101-1至AP101-3，STA多链路设备102包括隶属的两个STA102-1和STA102-2，STA多链路设备103包括2个隶属的STA103-1，STA103-2，STA103-3，STA104为单链路设备，AP多链路设备可以分别采用链路1和链路3与STA多链路设备102进行通信，采用链路2和链路3与多链路103进行通信，采用链路1与STA104通信。一个示例中，STA104工作在2.4GHz频段；STA多链路设备103包括STA103-1和STA103-2，STA103-1工作在5GHz频段，STA103-2工作在6GHz频段；STA多链路设备102包括STA102-1和STA102-2，STA102-1工作在2.4GHz频段，STA102-2工作在6GHz频段。AP多链路设备中工作在2.4GHz频段的AP101-1可以通过链路1与STA104和STA多链路设备102中的STA102-2之间传输上行或下行数据。AP多链路设备中工作在5GHz频段的AP101-2可以通过链路2与STA多链路设备103中工作在5GHz频段的STA103-1之间传输上行或下行数据。AP多链路设备101中工作在6GHz频段的AP101-3可通过链路3与STA多链路设备102中工作在6GHz频段的STA102-2之间传输上行或下行数据，还可通过链路3与STA多链路设备中的STA103-2之间传输上行或下行数据。
需要说明的是，图3(a)仅示出了AP多链路设备支持2个频段，图3(b)仅以AP多链路设备支持三个频段(2.4GHz，5GHz，6GHz)，每个频段对应一条链路，AP多链路设备101可以工作在链路1、链路2或链路3中的一条或多条链路为例进行示意。在AP侧或者STA侧，这里的链路还可以理解为工作在该链路上的站点。实际应用中，AP多链路设备和STA多链路设备还可以支持更多或更少的频段，即AP多链路设备和STA多链路设备可以工作在更多条链路或更少条链路上，本申请实施例对此并不进行限定。
示例性的，多链路设备为具有无线通信功能的装置，该装置可以为一个整机的设备，还可以是安装在整机设备中的芯片或处理系统等，安装这些芯片或处理系统的设备可以在这些芯片或处理系统的控制下，实现本申请实施例的方法和功能。
多链路设备可以支持同时收发(simultaneously transmit and receive，STR)数据，或者，多链路设备可以不支持同时收发数据。其中，支持同时收发数据是指：多链路设备在一条链路上发送数据的过程中，可以另一条链路上接收到数据。不支持同时收发数据是指：多链路设备在一条链路上发送数据的过程中，不能在另一条链路上接收到数据。
对于不能同时收发(not simultaneously transmit and receive，NSTR)的多链路设备来说，由于能力受限，当其在一条链路发送信号的时候，可能无法在另一条链路上进行信号接收。如果这时候在另一条链路上有数据包需要接收，则NSTR多链路设备可能接收不到数据包，导致数据包的丢失。为了避免丢包的情况发生，802.11协议中提出一种同步多链路通信方式。同步多链路通信方式要求将在不同链路上发送给NSTR多链路设备 的PPDU的传输结束时刻对齐，以降低NSTR多链路设备出现需要同时收发的概率。
目前，现有的错误恢复机制并不适用于NSTR MLD使用触发帧的通信场景。具体的，在一条链路上出现与触发帧相关的错误(例如触发帧传输失败或者触发帧所触发的TB PPDU发生错误)时，现有的错误恢复机制可能无法成功进行错误恢复，或者在成功错误恢复之后可能使得MLD出现需要同时收发的情况。
例如，如图4所示，不支持STR的发送端MLD在链路1和链路2上分别通过RTS-CTS机制获取到TXOP。之后，发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20。在传输过程中，触发帧10传输失败，触发帧20传输成功。而在链路1上，由于发送端MLD在确定触发帧10传输失败之后，可以进行PIFS错误恢复。但是，经过PIFS错误恢复之后，发送端MLD在链路1上发送的触发帧11会和正在接收的TB PPDU20发生冲突。这样一来，可能导致发送端MLD可能无法在链路2上正常接收TB PPDU20。相应的，发送端MLD也无法在链路2上回复TB PPDU20对应的BA20。图4中BA20以虚线框表示表示未发送。
又例如，如图5所示，不支持STR的发送端MLD在链路1和链路2上分别通过RTS-CTS机制获取到TXOP。之后，发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20。在传输过程中，触发帧10传输失败，触发帧20传输成功。发送端MLD在确定触发帧10传输失败之后，可以进行退避恢复。在退避成功后，发送MLD在链路1上发送触发帧11。但是，链路1上触发帧11所触发的TB PPDU11的传输时间与链路2上发送端MLD发送的触发帧21的传输时间相冲突，导致发送端MLD出现需要同时收发的情况，影响不支持STR能力的发送端MLD的正常通信。
因此，针对NSTR MLD，有必要设计合理的方案以实现与触发帧相关的错误恢复。
为了解决这一技术问题，本申请提供触发帧发送方法及装置。下面结合说明书附图，对本申请实施例进行具体介绍。
如图6所示，为本申请实施例提供的一种触发帧发送方法，该方法包括以下步骤：
S101、MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧。
其中，MLD在第一链路和第二链路上不支持STR。或者说，MLD在第一链路和第二链路上不具备STR能力。
应理解，第一链路和第二链路是MLD配置的多个链路中的任意两个，对此不作限制。
在本申请实施例中，MLD可以通过第一链路和第二链路与另一个MLD通信。或者，MLD通过第一链路和第一设备通信，以及通过第二链路和第二设备通信，第一设备和第二设备是独立的两个设备。
在本申请实施例中，MLD可以是AP MLD，或者STA MLD。
在本申请实施例中，第一触发帧的传输结束时刻与第二触发帧的传输结束时刻是对齐的。这样一来，保证MLD采用了同步多链路通信方式，降低MLD同时收发的概率。
S102、在MLD通过第一链路未成功接收到由第一触发帧所触发的第一TB PPDU，以及通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧，在第三时刻通过第二链路发送第四触发帧。
应理解，“成功接收”可以替换为“正确接收”或者其他类似的描述，对此不作限 定。
在本申请实施例中，第二时刻与第三时刻是对齐的。并且，第三触发帧的传输结束时刻与第四触发帧的传输结束时刻是对齐的。
应理解，两个时刻对齐可以是指两个时刻相同，或者两个时刻之间的偏差值在802.11协议允许的偏差范围内。示例性的，目前802.11协议允许的偏差范围可以为[-8μs，8μs]或者[-4μs，4μs]。在此统一说明，以下不再赘述。
可选的，由于第三触发帧和第四触发帧在传输开始时刻和传输结束时刻上均是对齐的，因此第三触发帧和第四触发帧在长度上期望是相同的。
应理解，第三触发帧是MLD通过第一链路发送第一触发帧之后，又发送的一个触发帧。
一种可能的设计中，第三触发帧所包括的参数可以和第一触发帧所包括的参数相同或者相似。从而，第三触发帧所触发的TB PPDU和第一触发帧所触发的TB PPDU相同。
可选的，基于该设计，第三触发帧可以由第一触发帧以及填充(padding)来构成的。
另一种可能的设计中，第三触发帧所包括的参数可以和第一触发帧所包括的参数不相同。从而，第三触发帧所触发的TB PPDU和第一触发帧所触发的TB PPDU不相同。
可选的，基于该设计，第三触发帧和第一触发帧可以用于触发同一个设备发送TB PPDU，也可以用于触发不同设备发送TB PPDU。
在本申请实施例中，MLD通过第一链路未成功接收到第一TB PPDU，包括以下两种情形：
情形1：MLD确定第一触发帧传输失败。
可选的，第一触发帧传输失败，可以替换为第一触发帧发生错误，对此不作限定。
一种可能的设计中，MLD确定第一触发帧传输失败，可以具体实现为：MLD在第一触发帧的传输结束时刻之后的预设时间间隔内未接收到第一TB PPDU。
例如，MLD的物理层在第一链路上发送第一触发帧之后，MLD的物理层会向MLD的MAC层发送用于确认第一触发帧传输结束的信号(例如PHY-TXEND.confirm primitive)。之后，如果MLD的MAC层在预设时间间隔内没有接收到MLD的物理层发送的用于确认接收到第一TB PPDU的信号(例如PHY-RXSTART.indication primitive)，则MLD可以确定第一链路上的第一触发帧传输失败。
示例性的，上述预设时间间隔可以为：aSIFSTime+aSlotTime+aRxPHYStart-Delay。其中，aSIFSTime表示一个SIFS的时长，aSlotTime表示一个时隙的时长，aRxPHYStart-delay表示接收端天线上的PPDU的开始到PHY-RXSTART.indication primitive发出的延迟。
情形2：MLD确定接收到的第一TB PPDU发生错误。
一种可能的设计中，如果MLD接收到第一TB PPDU，但是根据第一TB PPDU计算出来的帧校验序列(frame check sequence，FCS)与第一TB PPDU携带的FCS不一致，则MLD可以确定接收到的第一TB PPDU发生错误。
另一种可能的设计中，MLD的MAC层接收到物理层发送的与第一TB PPDU相关的PHY-RXEND.indication primitive。若PHY-RXEND.indication primitive携带的参数接收错误(RXERROR)是除了未出错(NoError)之外的其他取值(例如格式违反(FormatViolation)， 载波丢失(CarrierLost)，不支持的速率(UnsupportedRate)，过滤的(Filtered)等)，则MLD可以确定接收到的第一TB PPDU发生错误。
下面对MLD可以采用的错误恢复方案进行具体介绍。
错误恢复方案1、在MLD通过第一链路未成功接收到第一TB PPDU之后，MLD在第二TB PPDU的BA的传输结束时刻之后检测第一链路的信道状态。在第一链路在第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内处于空闲状态的情况下，MLD可以在第二时刻通过第一链路发送第三触发帧。
可选的，检测第一链路的信道状态的起始时刻可以为第二TB PPDU的BA的传输结束时刻或者第二TB PPDU的BA的传输结束时刻之后的时刻。
可选的，针对错误恢复方案1，若第一链路在第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内未持续处于空闲状态，则说明错误恢复失败，从而MLD可以不在第二时刻通过第一链路发送第三触发帧。
应理解，检测第一链路的信道状态，可以采用CCA检测方式，或者其他检测方式，对此不作限定。
对于NSTR MLD来说，MLD在第一链路上进行信道检测的过程中，如果MLD在第二链路上发送信息(例如第二TB PPDU的BA)，则会导致第一链路受到第二链路发送的信息的干扰，从而导致第一链路上信道检测结果为繁忙状态，进而导致第一链路上的错误恢复失败。因此，区别于相关技术中的PIFS错误恢复，错误恢复方案1中，检测第一链路的信道状态的起始时刻为第二TB PPDU的BA的传输结束时刻或者第二TB PPDU的BA的传输结束时刻之后的时刻。这样一来，在第一链路的信道检测的过程中，避免第二链路上发送的第二TB PPDU的BA影响到第一链路的信道状态的检测结果，保证错误恢复的正常执行。
现有的PIFS错误恢复要求第一链路保持空闲状态的持续时间为PIFS。但是，目前802.11协议中定义BA的传输结束时刻与下一个触发帧的传输起始时刻之间的时间间隔为SIFS。但是，若第四触发帧的传输起始时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔为SIFS，而SIFS与PIFS不一致，则可能会导致第四触发帧与第三触发帧不能同步发送。对此，一种可能的设计中，本申请实施例中将第四触发帧的传输起始时刻(也即第三时刻)与第二TB PPDU的BA的传输结束时刻之间的时间间隔设置为第一预设时间间隔。
可选的，第一预设时间间隔可以为PIFS。这样一来，错误恢复方案1可以遵循现有技术中对PIFS错误恢复的规定。
或者，第一预设时间间隔可以为其他类型的帧间间隔。例如，第一预设时间间隔可以为SIFS。
示例性的，以图7来对上述错误恢复方案1进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。之后，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。发送端MLD在BA20的传输结束时刻起进行信道检测。在BA20传输结束时刻起的PIFS内第一链路处于空闲状态的情况下，发送端MLD在链路1上发送触发帧11。并且，在发送触发帧11的同一时刻，发送端MLD在 链路2上发送触发帧21。触发帧11和触发帧21对齐。这样一来，保证后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
其中，图7中的TB PPDU10用虚线框表示未收到，后续附图中的虚线框也表示框内的内容未收到，在此统一说明，下述实施例不再赘述。
示例性的，以图8来对上述错误恢复方案1进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。发送端MLD在链路2上成功接收到TB PPDU20，并在间隔SIFS之后回复TB PPDU20的BA20。由于发送端MLD在链路1上接收到的TB PPDU10发生错误，因此发送端MLD在BA20的传输结束时刻起进行信道检测。在BA20传输结束时刻起的PIFS内第一链路处于空闲状态的情况下，发送端MLD在链路1上发送触发帧11。并且，在发送触发帧11的同一时刻，发送端MLD在链路2上发送触发帧21。触发帧11和触发帧21对齐。这样一来，保证后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
错误恢复方案2、在MLD通过第一链路未成功接收到第一TB PPDU之后，MLD在第一链路上执行退避流程。在第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，MLD将第一链路的退避计数器保持为0，直至第二TB PPDU的BA传输完毕。之后，MLD在第二TB PPDU的BA的传输结束时刻起检测第一链路的信道状态。在第一链路在第二TB PPDU的BA的传输结束时刻之后的第二预设时间间隔内处于空闲状态的情况下，MLD在第二时刻通过第一链路发送第三触发帧。
应理解，在第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，MLD将第一链路的退避计数器保持为0，直至第二TB PPDU的BA传输完毕，其目的在于保证第一链路上的第三触发帧和第二链路上的第四触发帧可以同步发送。
可选的，针对错误恢复方案2，若第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前未退避到0，则说明错误恢复失败，从而MLD可以不在第二时刻通过第一链路发送第三触发帧。
一方面，第二TB PPDU的BA传输过程中，第一链路会因为该第二TB PPDU的BA的影响而导致信道检测结果为繁忙状态。因此，MLD会暂停(suspend)退避流程。在第二TB PPDU的BA传输完毕之后，第一链路上的信道状态从繁忙状态转为空闲状态。但是，根据现有的退避机制，第一链路需要保持一段时间(例如DIFS、EIFS或者AIFS)处于空闲状态，才能继续退避流程，从而竞争到信道。另一方面，目前，802.11协议中定义BA的传输结束时刻与下一个触发帧的传输起始时刻之间的时间间隔为SIFS。这样一来，如果第二预设时间间隔依然设置为DIFS、EIFS或者AIFS，而第二TB PPDU的传输结束时刻与第四触发帧的传输起始时刻之间的时间间隔设置为SIFS，则会导致第三触发帧和第四触发帧不能同步发送。
对此，一种可能的设计中，本申请实施例将第四触发帧的传输起始时刻(也即第三时刻)与第二TB PPDU的BA的传输结束时刻之间的时间间隔设置为第二预设时间间隔。
可选的，第二预设时间间隔可以为SIFS。这样一来，可以不用修改现有协议所定义的BA的传输结束时刻与下一个触发帧的传输起始时刻之间的时间间隔。
或者，第二预设时间间隔也可以为其他类型的帧间间隔，对此不作限定。例如，第 二预设时间间隔可以为PIFS、DIFS、AIFS、或EIFS。
示例性的，以图9来对上述错误恢复方案2进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。之后，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。在触发帧10传输失败之后，发送端MLD在链路1上执行退避流程。若链路1的退避计数器在BA20的传输开始时刻之前退避到0，则发送端MLD会将链路1的退避计数器保持为0，直至BA20的传输完毕。在BA20的传输完毕之后，发送端MLD会检测链路1的信道状态。当链路1处于空闲状态达到SIFS时，发送端MLD在链路1上发送触发帧11。另外，发送端MLD会从BA20的传输结束时刻起的SIFS之后在链路2上发送触发帧21。可见，触发帧11和触发帧21可以对齐。这样一来，保证后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
错误恢复方案3、在MLD通过第一链路未成功接收到第一TB PPDU之后，MLD在第四时刻通过第一链路发送dummy帧，第四时刻与第二TB PPDU的BA的传输开始时刻对齐，dummy帧的长度与第二TB PPDU的BA的长度相同。之后，MLD在第二时刻通过第一链路发送第三触发帧。其中，第二时刻与dummy帧的传输结束时刻之间的时间间隔为SIFS。
应理解，MLD发送dummy帧的目的在于：维持MLD在第一链路的TXOP，以避免第一链路的TXOP被其他设备抢占。
上述dummy帧可以是任意类型的帧，例如控制帧、数据帧等，对此不作限定。
由于dummy帧的传输开始时刻(也即第四时刻)与第二TB PPDU的BA的传输开始时刻对齐，并且dummy帧的长度与第二TB PPDU的BA的长度相同，从而保证dummy帧的传输结束时刻与第二TB PPDU的BA的传输结束时刻对齐。
应理解，dummy帧的传输结束时刻与第二TB PPDU的BA的传输结束时刻对齐可以是指dummy帧的传输结束时刻与第二TB PPDU的BA的传输结束时刻相同，或者dummy帧的传输结束时刻与第二TB PPDU的BA的传输结束时刻之间的偏差值在802.11协议允许的偏差范围内。示例性的，目前802.11协议允许的偏差范围可以为[-8μs，8μs]或者[-4μs，4μs]。
应理解，针对错误恢复方案3，本申请实施例不限制第二TB PPDU的传输开始时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔。应理解，该时间间隔可以在不同场景下具有不同的取值。例如，在第一触发帧传输失败的情况下，第二TB PPDU的传输开始时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔可以SIFS；或者，在第一TB PPDU发生错误的情况下，第二TB PPDU的传输开始时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔可以PIFS。
一种可能的实现方式中，MLD在发送dummy帧之前可以采用退避错误恢复，以确定是否可以发送dummy帧。例如，在MLD通过第一链路未成功接收到第一TB PPDU之后，MLD在第一链路上执行退避流程。在第一链路的退避计数器在第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，MLD将第一链路的退避计数器保持为0，直至第四时刻。之后，MLD在第四时刻通过第一链路发送dummy帧。
示例性的，以图10来对上述错误恢复方案3进行举例说明。发送端MLD在链路1 上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。之后，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。在触发帧10传输失败的情况下，发送端MLD在链路1上执行退避流程。并且，若在第四时刻之前链路1的退避计数器退避到0，则发送端MLD将链路1的退避计数器的计数值保持为0，直至到达第四时刻。之后，之后，发送端MLD在从dummy帧传输结束时刻起的SIFS之后通过链路1发送触发帧11，在BA20传输结束时刻起的SIFS之后通过链路1发送触发帧21。这样一来，保证触发帧11和触发帧21对齐，以及后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
另一种可能的实现方式中，MLD在发送dummy帧之前可以采用PIFS错误恢复，以确定是否可以发送dummy帧。例如，在MLD通过第一链路未成功接收到第一TB PPDU之后，MLD可以对第一链路进行信道检测。在MLD确定在第二TB PPDU的BA的传输开始时刻之前的PIFS内第一链路处于空闲状态的情况下，MLD在第四时刻通过第一链路发送dummy帧。
示例性的，以图11来对上述错误恢复方案3进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。之后，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。在触发帧10传输失败的情况下，发送端MLD检测链路1的信道状态。若在BA20传输开始时刻之前的PIFS内链路1保持空闲状态，则发送端MLD在第四时刻通过链路1发送dummy帧。之后，发送端MLD在从dummy帧传输结束时刻起的SIFS之后通过链路1发送触发帧11，在BA20传输结束时刻起的SIFS之后通过链路1发送触发帧21。这样一来，保证触发帧11和触发帧21对齐，以及后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
可选的，在第一TB PPDU发生错误的情况下，由于第一TB PPDU的传输结束时刻与第二TB PPDU的传输结束时刻存在一定的误差，因此本申请实施例可以将第二TB PPDU的BA的传输开始时刻与第二TB PPDU的传输结束时刻之间的时间间隔从SIFS修改为PIFS+偏差值。这样一来，一方面，保证MLD在第一TB PPDU传输结束时刻之后有足够的时间在链路1上完成错误恢复；另一方面，保证dummy帧的传输开始时刻与第二TB PPDU的BA的传输开始时刻对齐。
其中，偏差值可以为正数也可以为负数，对此不作限定。可选的，偏差值的取值范围可以为[-8μs，8μs]或者[-4μs，4μs]。示例性的，偏差值可以为8μs，4μs，-4μs，-8μs等。
示例性的，以图12来对上述错误恢复方案3进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。发送端MLD在链路1上接收到TB PPDU10，但是TB PPDU10出现错误。因此，发送端MLD在链路1上执行退避流程。若在第四时刻之前链路1的退避计数器退避到0，则发送端MLD将退避计数器的计数值保持为0，直至第四时刻到达。之后，发送端MLD在第四时刻通过通过链路1发送dummy帧。之后，发送端MLD在从dummy帧传输结束时刻起的SIFS之后通过链路1发送触发帧11，在BA20传输结束时刻起的SIFS之后通过链路1发送触 发帧21。这样一来，保证触发帧11和触发帧21对齐，以及后续TB PPDU11和TB PPDU21对齐，BA11和BA21对齐。
基于图6所示的实施例，在第一链路上未成功接收到由第一触发帧所触发的第一TB PPDU，而在第二链路上成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧，在第三时刻通过第二链路发送第四触发帧。可见，在第一链路上出现与第一触发帧相关的错误时，MLD还可以在第一链路上发送下一个触发帧(也即第三触发帧)，从而实现第一链路上的错误恢复。另外，由于第二时刻和第三时刻对齐，因此第三触发帧和第四触发帧是同步发送的，以降低MLD需要同时收发数据的情况发生的概率，保证MLD能够正常通信。
如图13所示，为本申请实施例提供的一种触发帧发送方法，该方法包括以下步骤：
S201、MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧。
其中，步骤S201可以参考图6所示实施例中步骤S101的相关描述，在此不再赘述。
S202、在由第一触发帧所触发的第一TB PPDU发生错误，以及MLD通过第二链路成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧。
其中，第二时刻位于第二TB PPDU的传输结束时刻之后，第二TB PPDU的BA的传输开始时刻之前。应理解，第二时刻可以为第二TB PPDU的传输结束时刻，或者第二TB PPDU的BA的传输开始时刻，又或者第二TB PPDU的传输结束时刻至第二TB PPDU的BA的传输开始时刻之间的时间段中的任意一个时刻。
示例性的，第二时刻可以与第二TB PPDU的传输结束时刻之间相距一个RX/TX时间，以降低MLD同时收发的情况发生的概率。
第二时刻位于第二TB PPDU的传输结束时刻之后，其原因在于：避免MLD接收第二TB PPDU和MLD发送第三触发帧同时发生，也即避免MLD出现同时需要收发的情况，保证MLD能够正常通信。
第二时刻位于第二TB PPDU的BA的传输开始时刻之前，其原因在于：由于MLD不支持STR，因此第二链路上发送第二TB PPDU的BA会使第一链路上的信道检测结果变为繁忙状态，进而干扰到第一链路上正常进行错误恢复。因此，可以通过使MLD在第二时刻之前完成错误恢复，以避免第一链路上的错误恢复受到第二TB PPDU的BA的影响。
第三触发帧以及第一TB PPDU发生错误的具体介绍，均可以参考上文中的相关描述，在此不再赘述。
下面对MLD可以采用的错误恢复方案进行介绍。
错误恢复方案4、在MLD确定接收到的由第一触发帧所触发的第一TB PPDU发生错误之后，MLD在第一链路上进行信道检测。在第一链路在第二时刻之前的PIFS内处于空闲状态的情况下，MLD在第二时刻通过第一链路发送第三触发帧。
示例性的，以图14来对错误恢复方案4进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。对于链路2，发送端MLD在链路2上接收到TB PPDU20， 并在链路2上回复TB PPDU20的BA20。对于链路1，发送端MLD检测链路1的信道状态；若在BA20的传输开始时刻之前的PIFS内链路1处于空闲状态，则发送端MLD在BA20的传输开始时刻起传输触发帧11。触发帧11的传输结束时刻与触发帧21的传输结束时刻对齐。
示例性的，以图15来对错误恢复方案4进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。对于链路2，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。对于链路1，发送端MLD检测链路1的信道状态；若在TB PPDU20传输结束时刻之前的PIFS内链路1处于空闲状态，则发送端MLD在TB PPDU20传输结束时刻起传输触发帧11。触发帧11的传输结束时刻与触发帧21的传输结束时刻对齐。
可选的，针对错误恢复方案4，若在第二时刻之前的PIFS内第一链路未保持空闲状态，则说明错误恢复失败，从而MLD可以不在第二时刻通过第一链路发送第三触发帧。
错误恢复方案5、在MLD确定接收到的由第一触发帧所触发的第一TB PPDU发生错误之后，MLD在第一链路上执行退避流程。在第一链路的退避计数器在第二时刻之前退避到0的情况下，MLD将第一链路的退避计数器保持为0，直至第二时刻。之后，MLD在第二时刻通过第一链路发送第三触发帧。
示例性的，以图16来对错误恢复方案4进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。对于链路2，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。对于链路1，发送端MLD在链路1上执行退避流程。若在BA20的传输开始时刻之前链路1的退避计数器退避到0，则发送端MLD将链路1的退避计数器保持为0，直至BA20的传输开始时刻。之后，发送端MLD在BA20的传输开始时刻通过链路1发送触发帧11。触发帧11的传输结束时刻与触发帧21的传输结束时刻对齐。
示例性的，以图17来对错误恢复方案4进行举例说明。发送端MLD在链路1上发送触发帧10，在链路2上发送触发帧20，触发帧10和触发帧20对齐。其中，触发帧10传输失败，触发帧20传输成功。对于链路2，发送端MLD在链路2上接收到TB PPDU20，并在链路2上回复TB PPDU20的BA20。对于链路1，发送端MLD在链路1上执行退避流程。若在TB PPDU20的传输结束时刻之前链路1的退避计数器退避到0，则发送端MLD将链路1的退避计数器保持为0，直至TB PPDU20的传输结束时刻。之后，发送端MLD在TB PPDU20的传输结束时刻通过链路1发送触发帧11。触发帧11的传输结束时刻与触发帧21的传输结束时刻对齐。
可选的，针对错误恢复方案5，若在第二时刻之前第一链路的退避计数器未退避到0，则说明错误恢复失败，从而MLD可以不在第二时刻通过第一链路发送第三触发帧。
应理解，MLD在成功接收到第二TB PPDU之后，MLD可以通过第二链路回复第二TB PPDU的BA。之后，MLD还可以在第三时刻通过第二链路发送第四触发帧。
其中，第三时刻晚于第二时刻。可选的，第三时刻与第二TB PPDU的BA的传输结束时刻之间的时间间隔为SIFS。
应理解，第四触发帧的传输结束时刻与第三触发帧的传输结束时刻对齐，以保证MLD使用同步链路通信方式，降低MLD出现需要同时收发的情况的概率。
应理解，第三时刻与第四时刻对齐可以是指第三时刻与第四时刻相同，或者第三时刻与第四时刻之间的偏差值在802.11协议允许的偏差范围内。示例性的，目前802.11协议允许的偏差范围可以为[-8μs，8μs]或者[-4μs，4μs]。
基于图13所示的实施例，在第一触发帧所触发的第一TB PPDU发生错误，而在第二链路上成功接收到由第二触发帧所触发的第二TB PPDU的情况下，MLD在第二时刻通过第一链路发送第三触发帧。可见，在第一链路上出现与第一触发帧相关的错误时，MLD还可以在第一链路上发送下一个触发帧(也即第三触发帧)，从而实现第一链路上的错误恢复。另外，第二时刻位于第二TB PPDU的传输结束时刻之后，第二TB PPDU的BA的传输开始时刻之前，以避免第二TB PPDU的BA对第一链路上的错误恢复造成的不利影响，使得第一链路的错误恢复能够正常进行。并且，由于第二TB PPDU的传输结束时刻之后，第二TB PPDU的BA的传输开始时刻之前的这段时间内，MLD不需要在第二链路上接收数据，因此，MLD在这段时间内发送第三触发帧，可以降低MLD需要同时收发数据的情况发生的概率，保证MLD能够正常通信。
需要说明的是，本申请实施例中，BA可以理解为一种回复帧。此外，回复帧还可以包括确认(acknowledgement，ACK)。从而，本申请中的BA也可以替换为ACK。也就是说，本申请中的BA仅表示回复帧，而该回复帧不一定必须为BA，也可以为ACK。
可选的，在多链路通信场景下，当STP MLD给NSTR MLD发送数据时，还可以要求STR MLD在不同链路上发送的PPDU在发送时刻对齐。其中，STR MLD发送的PPDU可以为上行(uplink，UL)PPDU或者下行(downlink，DL)PPDU。
应理解，两个PPDU的发送时刻对齐，可以是指这两个PPDU的发送时刻相同，或者两个PPDU的发送时刻之间的偏差值在802.11协议允许的偏差范围内。示例性的，目前802.11协议允许的偏差范围可以为[-8μs，8μs]或者[-4μs，4μs]。
上述主要从方法的角度对本申请实施例提供的方案进行了介绍。可以理解的是，MLD为了实现上述功能，其包含了执行每一个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本申请能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
本申请实施例可以根据上述方法示例对装置进行功能模块的划分，例如，可以对应每一个功能划分每一个功能模块，也可以将两个或两个以上的功能集成在一个功能模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。下面以采用对应每一个功能划分每一个功能模块为例进行说明：
如图18所示，为本申请实施例提供的一种通信装置，该通信装置包括：处理模块101和通信模块102。
一种可能的实现方式中，通信模块102执行图6中的步骤S101和S102，以及本申 请实施例中的其他通信操作(例如发送BA)。处理模块101用于控制通信模块执行图6中的步骤S102，以及本申请实施例中的其他处理操作(例如检测第一链路的信道状态)。
另一种可能的实现方式中，通信模块102执行图13中的步骤S201和S202，以及本申请实施例中的其他通信操作(例如发送BA)。处理模块101用于控制通信模块执行图13中的步骤S201和S202，以及本申请实施例中的其他处理操作(例如检测第一链路的信道状态)。
可选的，上述处理模块101可以包括至少两个处理子模块，每一个处理子模块可以负责一个链路上的处理操作。上述通信模块102可以包括至少两个通信子模块，每一个通信子模块可以负责一个链路上的通信操作。
图19是本申请实施例所述的通信装置可能的产品形态的结构图。
作为一种可能的产品形态，本申请实施例所述的通信装置可以为MLD，MLD包括处理器201和收发器202。
一种可能的实现方式中，收发器202执行图6中的步骤S101和S102，以及本申请实施例中的其他通信操作(例如发送BA)。处理器201用于控制通信模块执行图6中的步骤S102，以及本申请实施例中的其他处理操作(例如检测第一链路的信道状态)。
另一种可能的实现方式中，收发器202执行图13中的步骤S201和S202，以及本申请实施例中的其他通信操作(例如发送BA)。处理器201用于控制通信模块执行图13中的步骤S201和S202，以及本申请实施例中的其他处理操作(例如检测第一链路的信道状态)。
作为另一种可能的产品形态，本申请实施例所述的通信装置也可以由芯片来实现。该芯片包括：处理电路201和收发管脚202。可选的，该芯片还可以包括存储介质203。
作为另一种可能的产品形态，本申请实施例所述的通信装置也可以使用下述电路或者器件来实现：一个或多个现场可编程门阵列(field programmable gate array，FPGA)、可编程逻辑器件(programmable logic device，PLD)、控制器、状态机、门逻辑、分立硬件部件、任何其他适合的电路、或者能够执行本申请通篇所描述的各种功能的电路的任意组合。
可选的，本申请实施例还提供一种计算机可读存储介质，所述计算机可读存储介质存储计算机指令，当该计算机指令在计算机上运行时，使得计算机执行前述方法实施例中的通信方法。
可选的，本申请实施例还提供一种包含计算机指令的计算机程序产品，当该计算机指令在计算机上运行时，使得计算机执行前述方法实施例中的通信方法。
应理解，所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或者数据中心通过有线(例如同轴电缆、光纤、数字用户线)或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可以用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质(例如，软盘、硬盘、磁带)，光介质、或者半导体介质(例如固态硬盘)等。
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到，为描述的方 便和简洁，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。
应该理解到，在本申请所提供的几个实施例中所揭露的装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个装置，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是一个物理单元或多个物理单元，即可以位于一个地方，或者也可以分布到多个不同地方。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个可读取存储介质中。基于这样的理解，本申请实施例的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该软件产品存储在一个存储介质中，包括若干指令用以使得一个设备(可以是单片机，芯片等)或处理器(processor)执行本申请各个实施例所述方法的全部或部分步骤。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (30)

  1. 一种触发帧发送方法，其特征在于，所述方法包括：
    多链路设备MLD在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，所述第一触发帧的传输结束时刻与所述第二触发帧的传输结束时刻对齐；
    在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一基于触发帧的物理层协议数据单元TB PPDU，以及通过所述第二链路成功接收到由所述第二触发帧所触发的第二TB PPDU的情况下，所述MLD在第二时刻通过所述第一链路发送第三触发帧，以及在第三时刻通过所述第二链路发送第四触发帧，所述第二时刻和所述第三时刻对齐。
  2. 根据权利要求1所述的方法，其特征在于，在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，所述方法还包括：
    所述MLD在所述第二TB PPDU的块确认BA的传输结束时刻之后检测所述第一链路的信道状态。
  3. 根据权利要求2所述的方法，其特征在于，所述MLD在第二时刻通过所述第一链路发送第三触发帧，包括：
    在所述第一链路在所述第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内处于空闲状态的情况下，所述MLD在所述第二时刻通过所述第一链路发送所述第三触发帧。
  4. 根据权利要求3所述的方法，其特征在于，所述第三时刻与所述第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第一预设时间间隔。
  5. 根据权利要求3或4所述的方法，其特征在于，所述第一预设时间间隔为点协调功能帧间间隔PIFS。
  6. 根据权利要求1所述的方法，其特征在于，在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，所述方法还包括：
    所述MLD在所述第一链路上执行退避流程；
    在所述第一链路的退避计数器在所述第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，所述MLD将所述第一链路的退避计数器保持为0，直至所述第二TB PPDU的BA传输完毕；
    所述MLD在所述第二TB PPDU的BA的传输结束时刻起检测所述第一链路的信道状态。
  7. 根据权利要求6所述的方法，其特征在于，所述MLD在第二时刻通过所述第一链路发送第三触发帧，包括：
    在所述第一链路在所述第二TB PPDU的BA的传输结束时刻之后的第二预设时间间隔内处于空闲状态的情况下，所述MLD在所述第二时刻通过所述第一链路发送所述第三触发帧。
  8. 根据权利要求7所述的方法，其特征在于，所述第三时刻与所述第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第二预设时间间隔。
  9. 根据权利要求7或8所述的方法，其特征在于，所述第二预设时间间隔为短帧间 间隔SIFS。
  10. 根据权利要求1所述的方法，其特征在于，在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，所述方法还包括：
    所述MLD在第四时刻通过所述第一链路发送虚设dummy帧，所述第四时刻所述第二TB PPDU的BA的传输开始时刻对齐，所述dummy帧的长度与所述第二TB PPDU的BA的长度相同。
  11. 根据权利要求10所述的方法，其特征在于，在所述MLD在第四时刻通过所述第一链路发送dummy帧之前，所述方法还包括：
    所述MLD确定在所述第四时刻之前的PIFS内所述第一链路处于空闲状态。
  12. 根据权利要求10所述的方法，其特征在于，在所述MLD第四时刻通过所述第一链路发送dummy帧之前，所述方法还包括：
    所述MLD在所述第一链路上执行退避流程；
    当所述第一链路的退避计数器在所述第二TB PPDU的BA的传输开始时刻之前退避到0时，所述MLD将所述第一链路的退避计数器保持为0，直至所述第四时刻。
  13. 根据权利要求1至12任一项所述的方法，其特征在于，所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU，包括：
    所述MLD确定所述第一触发帧传输失败。
  14. 根据权利要求1至12任一项所述的方法，其特征在于，所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU，包括：
    所述MLD确定接收到的所述第一TB PPDU发生错误。
  15. 一种多链路设备MLD，其特征在于，包括：处理模块和所述处理模块连接的通信模块；
    所述通信模块，用于在第一时刻通过第一链路发送第一触发帧，以及在第一时刻通过第二链路发送第二触发帧，所述第一触发帧的传输结束时刻与所述第二触发帧的传输结束时刻对齐；
    所述处理模块，还用于在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU，以及通过所述第二链路成功接收到由所述第二触发帧所触发的第二TB PPDU的情况下，控制所述通信模块在第二时刻通过所述第一链路发送第三触发帧，以及在第三时刻通过所述第二链路发送第四触发帧，所述第二时刻和所述第三时刻对齐。
  16. 根据权利要求15所述的MLD，其特征在于，
    所述处理模块，还用于在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，在所述第二TB PPDU的BA的传输结束时刻之后检测所述第一链路的信道状态。
  17. 根据权利要求16所述的MLD，其特征在于，
    所述通信模块，用于在所述第一链路在所述第二TB PPDU的BA的传输结束时刻之后的第一预设时间间隔内处于空闲状态的情况下，在所述第二时刻通过所述第一链路发送所述第三触发帧。
  18. 根据权利要求17所述的MLD，其特征在于，所述第三时刻与所述第二TB PPDU 的BA的传输结束时刻之间的时间间隔等于第一预设时间间隔。
  19. 根据权利要求18所述的MLD，其特征在于，所述第一预设时间间隔为PIFS。
  20. 根据权利要求15所述的MLD，其特征在于，
    所述处理模块，还用于在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，在所述第一链路上执行退避流程；在所述第一链路的退避计数器在所述第二TB PPDU的BA的传输开始时刻之前退避到0的情况下，将所述第一链路的退避计数器保持为0，直至所述第二TB PPDU的BA传输完毕；在所述第二TB PPDU的BA的传输结束时刻起检测所述第一链路的信道状态。
  21. 根据权利要求20所述的MLD，其特征在于，
    所述通信模块，用于在所述第一链路在所述第二TB PPDU的BA的传输结束时刻之后的第二预设时间间隔内处于空闲状态的情况下，在所述第二时刻通过所述第一链路发送所述第三触发帧。
  22. 根据权利要求21所述的MLD，其特征在于，所述第三时刻与所述第二TB PPDU的BA的传输结束时刻之间的时间间隔等于第二预设时间间隔。
  23. 根据权利要求22所述的MLD，其特征在于，所述第二预设时间间隔为SIFS。
  24. 根据权利要求15所述的MLD，其特征在于，
    所述通信模块，还用于在所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU之后，在第四时刻通过所述第一链路发送dummy帧，所述第四时刻所述第二TB PPDU的BA的传输开始时刻对齐，所述dummy帧的长度与所述第二TB PPDU的BA的长度相同。
  25. 根据权利要求24所述的MLD，其特征在于，
    所述处理模块，还用于在所述通信模块在第四时刻通过所述第一链路发送dummy帧之前，确定在所述第四时刻之前的PIFS内所述第一链路处于空闲状态。
  26. 根据权利要求25所述的MLD，其特征在于，
    所述处理模块，还用于在所述第一链路上执行退避流程；当所述第一链路的退避计数器在所述第二TB PPDU的BA的传输开始时刻之前退避到0时，将所述第一链路的退避计数器保持为0，直至所述第四时刻。
  27. 根据权利要求15至26任一项所述的MLD，其特征在于，所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU，包括：
    所述MLD确定所述第一触发帧传输失败。
  28. 根据权利要求15至26任一项所述的MLD，其特征在于，所述MLD通过所述第一链路未成功接收到由所述第一触发帧所触发的第一TB PPDU，包括：
    所述MLD确定接收到的所述第一TB PPDU发生错误。
  29. 一种芯片，其特征在于，所述芯片包括处理电路和收发管脚；所述处理电路用于执行权利要求1至14中任一项所涉及的方法中的处理操作，所述收发管脚用于执行权利要求1至14中任一项所涉及的方法中的通信操作。
  30. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质存储计算机指令，当所述计算机指令在计算机上运行时，使得所述计算机执行权利要求1至14任一项所述的方法。
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