Channel access method and related equipment for multilink device

Abstract

To provide a channel access method and related equipment for a multilink device.SOLUTION: In a method, a multilink device performs first channel contention on a first link, and determines the initial value of a backoff counter in the first channel contention on the basis of the first value of a contention window. The multilink device may perform second channel contention on the first link when the value of the backoff counter becomes 0 in the first channel contention and the multilink device does not perform transmission on the first link, and the initial value of the backoff counter in the second channel contention is determined on the basis of the second value of the contention window, and the second value is equal to the first value or the minimum value of the contention window. According to an embodiment of the present application, balance between the backoff time and a contention collision probability can be achieved.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202010562039.8, filed with the State Intellectual Property Office of China on June 18, 2020, entitled "Channel Access Method for Multi-Link Device, and Related Apparatus," which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of wireless communication technologies, and in particular to a channel access method for a multi-link device and related apparatus. [Background technology]

[0003] With the development of wireless communication technology, more and more wireless communication devices support multi-link communication, for example, communication simultaneously on 2.4GHz, 5GHz, and 6GHz frequency bands, or communication simultaneously on different channels of the same frequency band. Such wireless communication devices are usually called multi-link devices (MLDs). It is obvious that the transmission speed can be greatly increased because a multi-link device can perform parallel communication on multiple links.

[0004] Multilink devices can increase transmission speed by performing parallel communication on multiple links, but when several multilink devices transmit on one link, the transmitted energy leaks onto another link, causing self-interference. As a result, the multilink device cannot correctly demodulate the data packets that need to be received on the other link. In other words, multilink devices do not support simultaneous transmit and receive (STR) on multiple links. Therefore, for non-simultaneous transmit and receive (non-STR) multilink devices, when channel contention occurs on two links and a transmission occurs on one link whose backoff counter reaches zero, the energy transmitted on that link leaks onto the other link, and as a result, channel contention continues on the other link because the channel is busy. As a result, only one link can be used for transmission.

[0005] Currently, in order to eliminate interference between two links, a multilink device may perform channel contention on one link, and after the backoff counter backs off to 0, it may wait for channel contention on the other link instead of performing data transmission, so that channel contention on the other link can be performed normally. However, since a multilink device does not perform data transmission after performing channel contention on a link and backing off to 0, how a multilink device can perform channel access again on a link becomes an urgent problem to be solved. Summary of the Invention [Means for solving the problem]

[0006] An embodiment of the present application provides a channel access method, and related apparatus, for a multi-link device, whereby when a multi-link device backs off to 0 on a link but does not transmit on the link, it performs channel contention / channel access on the link again and sets the contention window value unchanged or sets the contention window value to a minimum value, thereby achieving a balance between the backoff time and the contention collision probability.

[0007] The following describes the present application from various aspects. It should be understood that cross-reference may be made between the following implementation forms and beneficial effects of the various aspects.

[0008] According to a first aspect, an embodiment of the present application provides a channel access method applied to a multi-link device. The method includes: The multi-link device performs a first channel contention on a first link. When a value of a back-off counter becomes 0 in the first channel contention and the multi-link device does not transmit on the first link, the multi-link device may perform a second channel contention on the first link. An initial value of the back-off counter in the first channel contention is determined based on a first value of a contention window, and an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window. The second value may be equal to the first value, or the second value is a minimum value of the contention window.

[0009] Optionally, STR is not supported between the first link and the second link.

[0010] Optionally, the reason why the multilink device does not transmit on the first link includes: After the value of the back-off counter becomes 0 in the first channel contention, the multilink device suspends the first link and waits for the channel contention on the second link; When the time that the first link waits for the channel contention on the second link exceeds a preset time, if the state of the second link is still busy, this indicates that the back-off counter on the second link cannot back off to 0 for a long time. In this case, the multilink device performs the channel contention on the first link again, i.e., the multilink device performs the second channel contention on the first link.

[0011] Optionally, the reason why the multilink device does not transmit on the first link includes: After the value of the back-off counter becomes 0 in the first channel contention, the multilink device receives a data packet on the second link, and the length of the data packet exceeds a preset time, which indicates that a relatively long network allocation vector is set on the second link. In this case, the multilink device again performs channel contention on the first link, i.e., the multilink device performs second channel contention on the first link.

[0012] According to this solution, when a multilink device backs off to 0 on a link but does not transmit on that link, it performs channel contention / channel access on the link again and either sets the contention window value unchanged or sets the contention window value to a minimum value CWmin, thereby achieving a balance between the backoff time and the contention collision probability.

[0013] Regarding the first aspect, in one possible design, before the multilink device engages in second channel contention on the first link, the method further includes: the multilink device detects a state of the first link in a first time period; if the state of the first link in the first time period is idle, the multilink device uses a first value of a contention window during the first channel contention as a second value of a contention window during a next channel contention on the first link, or sets the second value of the contention window to a minimum value of the contention window; the first time period may be a clear channel assessment time, e.g., 4 μs or 9 μs.

[0014] Optionally, if the state of the first link in the first time period is busy, the multi-link device increases a first value of the contention window and uses the increased value as a second value of the contention window.

[0015] According to this solution, after the backoff counter backs off to 0 in the first channel contention, the state of the first link is determined to estimate whether the transmission on the first link will be successful, and the value of the contention window is set based on the estimation result. In this way, the size of the contention window can be adjusted more accurately and appropriately, thereby further obtaining a balance between the backoff time and the contention collision probability.

[0016] Regarding the first aspect, in one possible design, before the multilink device performs second channel contention on the first link, the method further includes: the multilink device performs channel contention on the second link and detects the state of the first link when the value of the back-off counter becomes 0 in the channel contention; if the state of the first link is busy, the multilink device suspends the second link, i.e., does not transmit on the second link; and only when the state of the first link changes from busy to idle, the multilink device performs second channel contention on the first link.

[0017] Optionally, the multilink device detects the state of the second link when the value of the backoff counter becomes 0 in the second channel contention, and the multilink device transmits data in parallel on the first link and the second link when the state of the second link is idle.

[0018] According to this solution, after the multi-link device backs off to 0 on the first link, in the process of waiting for channel contention on the second link, the state of the first link changes to busy, when the multi-link device backs off to 0 on the second link, the first link is still in busy, and after the state of the first link returns to idle, the multi-link device again performs channel contention on the first link, and transmits data on the first link and the second link in parallel after backing off to 0. In this way, the peak transmission rate can be increased.

[0019] Regarding the first aspect, in one possible design, before the multilink device performs second channel contention on the first link, the method further includes: the multilink device performs channel contention on the second link, and detects the state of the first link when the value of the backoff counter becomes 0 in the channel contention; the multilink device may transmit data on the second link if the state of the first link is busy.

[0020] Optionally, the multilink device performs second channel contention on the first link only when a state of the first link changes from a busy state to an idle state, and the multilink device transmits data on the first link when a value of a back-off counter becomes zero in the second channel contention.

[0021] According to this solution, after the multilink device backs off to 0 on the first link, in the process of waiting for channel contention on the second link, the state of the first link changes to busy, and when the multilink device backs off to 0 on the second link, the first link is still in busy state, in this case, the multilink device can directly transmit data on the second link. In this way, channel utilization can be improved.

[0022] According to a second aspect, an embodiment of the present application provides a communication device, which may be a multilink device or a chip such as a Wi-Fi chip in the multilink device, The multi-link device includes a processing unit configured to perform a first channel contention on the first link, and an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window, and the processing unit is further configured to perform a second channel contention on the first link when a value of the back-off counter in the first channel contention becomes 0 and the multi-link device does not transmit on the first link, and an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window, and the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window.

[0023] Regarding the second aspect, in one possible design, the multilink device not transmitting on the first link includes a state of the second link being busy when the time the first link waits for channel contention on the second link exceeds a preset time.

[0024] Regarding the second aspect, in one possible design, the multilink device not transmitting on the first link includes a length of a data packet received by the multilink device on the second link exceeding a preset time after a backoff counter value becomes zero in the first channel contention.

[0025] Regarding the second aspect, in one possible design, simultaneous transmit and receive STRs are not supported between the first link and the second link.

[0026] Regarding the second aspect, in one possible design, the processing unit is further configured to detect a state of the first link in a first period, and when the state of the first link in the first period is an idle state, determine the first value of the contention window as the second value or determine the second value of the contention window as a minimum value of the contention window.

[0027] Regarding the second aspect, in one possible design, the processing unit is further configured to: perform channel contention on the second link, detect the state of the first link when the value of the back-off counter becomes 0 in the channel contention, and suspend the second link when the state of the first link is busy. The processing unit is configured to perform the second channel contention on the first link when the state of the first link changes from busy to idle.

[0028] Regarding the second aspect, in one possible design, the communication apparatus further includes a transceiver unit. The processing unit is further configured to detect, for the multilink device, a state of the second link when a value of the backoff counter becomes 0 in the second channel contention. The transceiver unit is configured to transmit data in parallel on the first link and the second link when a state of the second link is an idle state.

[0029] Regarding the second aspect, in one possible design, the communication device further includes a transceiver unit. The processing unit is further configured to perform channel contention on the second link and detect a state of the first link when a value of the backoff counter becomes 0 in the channel contention. The transceiver unit is configured to transmit data on the second link when a state of the first link is busy.

[0030] According to a third aspect, an embodiment of the present application provides another communication device, specifically a multilink device including a processor. The processor is configured to support the multilink device in performing corresponding functions in the method according to the first aspect. Optionally, the multilink device may further include a memory. The memory is configured to be connected to the processor and stores program instructions and data required for the multilink device.

[0031] Specifically, the processor is configured to: perform a first channel contention on a first link, wherein an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window; and, when a value of the back-off counter in the first channel contention becomes 0 and the multi-link device does not transmit on the first link, perform a second channel contention on the first link, wherein an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window, wherein the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window.

[0032] Optionally, the multilink device may further include a transceiver configured to support communication between the multilink device and another device, for example, to transmit data in parallel on the first link and on the second link when the state of the second link is idle, or to transmit data on the second link when the state of the first link is busy.

[0033] According to a fourth aspect, an embodiment of the present application provides a chip or chip system including a processing circuit configured to: perform a first channel contention on a first link, where an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window; and, when a value of the back-off counter in the first channel contention becomes zero and the multi-link device does not transmit on the first link, perform a second channel contention on the first link, where an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window, where the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window.

[0034] According to a fifth aspect, the present application provides a computer-readable storage medium having instructions stored thereon that, when executed on a computer, enable the computer to perform a channel access method for a multi-link device according to the first aspect.

[0035] According to a sixth aspect, the present application provides a computer program product comprising instructions, which when executed on a computer enable the computer to perform a channel access method for a multi-link device according to the first aspect.

[0036] Through implementation of an embodiment of the present application, when a multi-link device backs off to 0 on a link but does not transmit on that link, a balance between backoff time and contention collision probability can be achieved by performing channel contention / channel access on the link again and setting the contention window value unchanged or setting the contention window value to a minimum value.

[0037] In order to describe the technical solutions in the embodiments of the present application more clearly, the following briefly describes the accompanying drawings used in describing the embodiments. [Brief description of the drawings]

[0038] [Figure 1] FIG. 2 is a schematic diagram of communication between Non-AP MLD and AP MLD according to an embodiment of the present application; [Diagram 2] 1 is a schematic diagram of the architecture of a wireless communication system according to an embodiment of the present application; [Figure 3a] FIG. 2 is a schematic diagram of a structure of a multi-link device according to an embodiment of the present application; [Figure 3b] FIG. 13 is a schematic diagram of another structure of another multi-link device according to an embodiment of the present application. [Figure 4] 2 is a schematic flowchart of a channel access method for a multi-link device according to an embodiment of the present application; [Figure 5a] FIG. 2 is a schematic diagram of a first time sequence of multi-link channel access according to an embodiment of the present application; [Figure 5b] FIG. 2 is a schematic diagram of a second time sequence of multi-link channel access according to an embodiment of the present application; [Figure 5c] FIG. 2 is a schematic diagram of a third time sequence of multi-link channel access according to an embodiment of the present application; [Figure 5d] FIG. 11 is a schematic diagram of a fourth time sequence of multi-link channel access according to an embodiment of the present application; [Figure 6] FIG. 1 is a schematic diagram of a single link multi-channel according to an embodiment of the present application; [Figure 7] 1 is a schematic diagram of the structure of a communication device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The following clearly and completely describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application.

[0040] In order to facilitate understanding of the channel access method for a multi-link device provided in the embodiment of the present application, the following describes the system architecture and / or application scenario of the channel access method for a multi-link device provided in the embodiment of the present application. It can be understood that the system architecture and / or scenario described in the embodiment of the present application are intended to more clearly describe the technical solution in the embodiment of the present application, and do not constitute limitations on the technical solution provided in the embodiment of the present application.

[0041] An embodiment of the present application provides a channel access method applied to a non-simultaneous transmission and reception (non-STR) multi-link device, whereby when a multi-link device backs off to 0 on a link but does not transmit on the link, it performs channel contention / channel access on the link again and sets the contention window value unchanged or sets the contention window value to a minimum value, thereby achieving a balance between the backoff time and the contention collision probability. The channel access method may be implemented by a communication device in a wireless communication system, or a chip or processor in the communication device. The communication device may be a wireless communication device that supports parallel transmission on multiple links. For example, the communication device may be referred to as a multi-link device or a multi-band device. Compared with a communication device that supports only single-link transmission, the multi-link device has higher transmission efficiency and higher throughput rate.

[0042] A multilink device includes one or more affiliated stations. An affiliated station is a logical station and may operate on one link, one frequency band, or one channel. An affiliated station may be an access point (AP) or a non-access point station (non-AP STA). For ease of description, in this application, a multilink device whose affiliated station is an AP is called a multilink AP, a multilink AP device, or an AP multilink device (AP MLD), and a multilink device whose affiliated station is a non-AP STA is called a multilink Non-AP, a multilink Non-AP device, or a Non-AP multilink device (Non-AP MLD).

[0043] Optionally, one multi-link device may include multiple logical stations, each of which operates on one link, although multiple logical stations are permitted to operate on one link.

[0044] Optionally, one or more non-AP STAs in the Non-AP MLD may establish an association relationship with one or more APs in the AP MLD and then communicate with one or more APs. Figure 1 is a schematic diagram of communication between the Non-AP MLD and the AP MLD according to an embodiment of the present application. As shown in Figure 1, the AP MLD includes AP1, AP2, ..., and APn, and the Non-AP MLD includes STA1, STA2, ..., and STAn. The AP MLD and the Non-AP MLD may communicate in parallel on link 1, link 2, ..., and link n. An association relationship is established between STA1 in the Non-AP MLD and AP1 in the AP MLD, an association relationship is established between STA2 in the Non-AP MLD and AP2 in the AP MLD, and an association relationship is established between STAn in the Non-AP MLD and APn in the AP MLD.

[0045] Optionally, the multi-link device may implement wireless communication according to the IEEE 802.11 series of protocols, for example, compliant with stations having extremely high throughput (EHT) or compliant with stations based on or compatible with IEEE 802.11be, and may communicate with other devices.

[0046] The channel access method for multi-link devices provided in an embodiment of the present application can be applied to a wireless local area network (WLAN). Figure 2 is a schematic diagram of an architecture of a wireless communication system according to an embodiment of the present application. As shown in Figure 2, the wireless communication system includes at least one AP MLD and at least one Non-AP MLD. The AP MLD is a multi-link device that serves the Non-AP MLD. The Non-AP MLD and the AP MLD can communicate with each other over multiple links. One AP in the AP MLD can communicate with one STA in the Non-AP MLD over one link. It can be understood that the number of AP MLDs and the number of Non-AP MLDs in Figure 2 are merely examples.

[0047] For example, a multi-link device (here, it may be a Non-AP MLD or an AP MLD) is a device having a wireless communication function. The device may be an entire device, or a chip or a processing system installed in the entire device, etc. The device in which the chip or processing system is installed may implement the method and function in the embodiment of the present application under the control of the chip or processing system. For example, the Non-AP multi-link device in the embodiment of the present application may have a wireless transceiver function, support 802.11 series protocols, and communicate with an AP multi-link device or another Non-AP multi-link device. For example, the Non-AP multi-link device is any user communication device that allows a user to communicate with an AP and thereby communicate with a WLAN. For example, the Non-AP multilink device may be a user equipment that can be connected to a network, such as a tablet computer, a desktop computer, a laptop computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, a notebook, a personal digital assistant (PDA), or a mobile phone, or may be an Internet of Things node in the Internet of Things, or may be an in-vehicle communication device in the Internet of Vehicles. The Non-AP multilink device may alternatively be a chip and processing system in the aforementioned terminal. The AP multilink device may be a device that provides services to the Non-AP multilink device and may support 802.11 series protocols. For example, the AP multilink device may be a communication entity such as a communication server, a router, a switch, or a bridge. Alternatively, the AP multilink device may include various forms of macro base stations, micro base stations, relay stations, etc. Of course, the AP multilink device may alternatively be a chip and processing system in these devices in various forms.

[0048] It can be understood that the multi-link device may support high-speed low-latency transmission. With the continuous evolution of application scenarios of wireless local area networks, the multi-link device may be further applied to more scenarios, such as sensor nodes in smart cities (e.g., smart water meters, smart electric meters, smart air detection nodes), smart devices in smart homes (e.g., smart cameras, projectors, displays, televisions, stereos, refrigerators, washing machines), nodes in the Internet of Things, entertainment terminals (e.g., wearable devices such as AR and VR), smart devices in smart offices (e.g., printers and projectors), Internet of Vehicles devices in the Internet of Vehicles, as well as some infrastructures in daily life scenarios (e.g., vending machines, self-service navigation stations in supermarkets, self-service cash register devices, and self-service ordering machines). The specific form of the multi-link device is not limited in the embodiments of this application, and the description in this specification is merely an example. The 802.11 protocol may be a protocol that supports 802.11be or is compatible with 802.11be.

[0049] Optionally, Fig. 3a is a schematic diagram of a structure of a multi-link device according to an embodiment of the present application. The IEEE 802.11 standard focuses on the 802.11 physical layer (PHY) part and the media access control (MAC) layer part in a multi-link device. As shown in Fig. 3a, multiple STAs included in the multi-link device are independent of each other in the low MAC layer and the PHY layer, and are also independent of each other in the high MAC layer. Fig. 3b is a schematic diagram of another structure of a multi-link device according to an embodiment of the present application. As shown in Fig. 3b, multiple STAs included in the multi-link device are independent of each other in the low MAC layer and the PHY layer, and share a high MAC layer. Of course, a Non-AP multi-link device may use a structure in which the high MAC layers are independent of each other, or a structure in which the high MAC layers are shared. Similarly, an AP multi-link device may use a structure in which the high MAC layers are shared, or a structure in which the high MAC layers are independent of each other. The schematic diagram of the internal structure of the multi-link device is not limited in the embodiment of the present application. Figure 3a and Figure 3b are merely examples for explanation. For example, the high MAC layer or the low MAC layer may be implemented by one processor in the chip system of the multi-link device, or may be implemented separately by different processing modules in the chip system.

[0050] For example, the multi-link device in the embodiment of the present application may be a single antenna device, or may be a multi-antenna device, for example a device having three or more antennas. The number of antennas included in the multi-link device is not limited in the embodiment of the present application. In the embodiment of the present application, the multi-link device may allow services of the same access category (AC) to be transmitted on different links, and may even allow the same data packet to be transmitted on different links, or may not allow services of the same access category to be transmitted on different links, but may allow services of different access categories to be transmitted on different links.

[0051] The frequency bands in which the multi-link device operates may include one or more of the sub-1 GHz, 2.4 GHz, 5 GHz, 6 GHz, and high frequency 60 GHz frequency bands.

[0052] The above describes the system architecture and / or application scenario of the channel access method for a multi-link device provided in the embodiment of the present application. The following further describes in detail the channel access method for a multi-link device provided in the embodiment of the present application with reference to the accompanying drawings.

[0053] Optionally, the multi-link device in the embodiment of the present application may be the Non-AP MLD in Fig. 2 or the AP MLD in Fig. 2. This is not limited in the embodiment of the present application.

[0054] Optionally, the multi-link device referred to in the embodiment of the present application does not support STR on two links. It can be understood that "supports STR" in the present application may mean that the device has STR capability and uses the STR capability in the current communication, and "does not support STR" may mean that the device does not have STR capability, or that the device has STR capability but does not use the STR capability in the current communication. It can be further understood that in some cases, some links of the multi-link device may switch between STR and non-STR, i.e., from supporting STR to not supporting STR, or from not supporting STR to supporting STR.

[0055] 4 is a schematic flowchart of a channel access method for a multi-link device according to an embodiment of the present application. As shown in FIG. 4, the channel access method for a multi-link device includes, but is not limited to, the following steps:

[0056] S401: A multi-link device performs a first channel contention on a first link, and an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window.

[0057] Specifically, the multilink device may perform a first channel contention on a first link, and may suspend the first link after the backoff counter backs off to 0 to wait for the multilink device to perform channel contention on a second link. It can be understood that "suspend" in this application may be understood as "not transmitting", and "suspending the first link" may mean that no transmission is performed on the first link.

[0058] Optionally, the channel contention may include a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism or an enhanced distributed channel access (EDCA) mechanism. In order to ensure that the access point and the station can access the wireless medium without colliding with each other, the CSMA / CA mechanism is used in 802.11. This mechanism is also called a distributed coordination function (DCF). The CSMA / CA mechanism is specifically as follows: Before transmitting data, the station needs to perform a clear channel access (CCA) on the wireless medium. If the wireless medium is idle for a certain period (e.g., distributed inter-frame space (DIFS)), the station may initiate a random backoff process. If the wireless medium is busy for that period, the station needs to wait until the wireless medium becomes idle and then remains idle for a certain period (e.g., DIFS) before initiating the random backoff process. After the random backoff process is completed, the station may perform a frame exchange. The backoff time in the random backoff process is equal to the product of the random backoff value and the slot time. The random backoff value is a value randomly selected from the evenly distributed contention window [0, CW]. It can be understood that the backoff time in the random backoff process is equal to the initial value of the backoff counter in the channel contention.

[0059] Optionally, in the CSMA / CA mechanism, the contention window (CW) has multiple values, and when a station makes an Initial Attempt for channel contention, the value of CW is the minimum value, i.e., CWmin. Every time a transmission fails (e.g., a collision occurs), a retransmission needs to be performed, and channel contention is performed again. In this case, the value of CW increases continuously until it reaches the maximum value of CW, i.e., CWmax. When data is successfully transmitted / transmitted, CW is reset to CWmin.

[0060] The EDCA mechanism is an extension of DCF, which allows services of different access categories to have different EDCA parameter sets. The EDCA parameter set includes parameters such as CWmin, CWmax, and arbitration inter-frame space (AIFS). The EDCA parameters of different access categories are listed in Table 1, where AC_VO indicates that the access category is a voice flow, AC_VI indicates that the access category is a video flow, AC_BE indicates that the access category is a best effort flow, and AC_BK indicates that the access category is a background flow.

[0061] [Table 1]

[0062] The random backoff process of a service of a specific access category is basically the same as that of DCF. The difference is that AIFS replaces DIFS in DCF. In other words, when the channel returns to an idle state, the channel needs to remain idle at AIFS before the random backoff process can take place. The AIFS calculation method can be to obtain the sum of the short inter-frame space (SIFS) and the product of the adjustment inter-frame space number (AIFS number, AIFSN) and a slot time (a Slot Time), that is, AIFS[AC]=a SIFS time+AIFSN[AC]*(a Slot Time). It can be understood that the units of both AIFS and SIFS are time units.

[0063] Optionally, the aforementioned first channel contention may be CSMA / CA or EDCA. The initial value of the back-off counter in the first channel contention may be determined based on the first value of the contention window. In the channel contention process, the value of the back-off counter decreases from the initial value until the value of the back-off counter becomes 0. It can be understood that if the multi-link device attempts channel contention on the first link for the first time, the first value may be CWmin. If the multi-link device does not attempt channel contention on the first link for the first time, the first value of the contention window is determined according to the CW change rule in the CSMA / CA mechanism, specifically, the value of CW is continuously increased when transmission fails, and the value of CW is set to CWmin when transmission succeeds.

[0064] S402: When the value of the backoff counter becomes 0 in the first channel contention and the multi-link device does not transmit on the first link, the multi-link device performs a second channel contention on the first link, and an initial value of the backoff counter in the second channel contention is determined based on a second value of a contention window, and the second value of the contention window is equal to the first value of the contention window, or the second value of the contention window is equal to the minimum value of the contention window.

[0065] Specifically, after the value of the back-off counter is backed off to 0 in the first channel contention, if the back-off counter on the second link is not yet backed off to 0, the multilink device does not transmit on the first link and waits for channel contention on the second link. When the time that the first link waits for channel contention on the second link exceeds a preset time, if the state of the second link is still busy, this indicates that the second link is busy for a long time, and the multilink device may stop performing parallel transmission on the first link and the second link. In this case, the multilink device may perform second channel contention on the first link, and may transmit data on the first link after the back-off counter is backed off to 0 in the second channel contention. Alternatively, if the length of a network allocation vector (NAV) in a data packet received by the multilink device on the second link exceeds a preset time after the backoff counter value becomes 0 in the first channel contention, this indicates that a relatively long NAV is set on the second link, and the multilink device may also stop performing parallel transmission on the first link and the second link. In this case, the multilink device may perform second channel contention on the first link and may transmit data on the first link after the backoff counter backs off to 0 in the second channel contention. The multilink device does not support simultaneous transmission and reception between the first link and the second link, i.e., is non-STR.

[0066] It can be understood that "data transmission" and "transmitting data" as referred to in this application generally refer to communication, and "data" generally refers to communication information and is not limited to data information, but may alternatively be signaling information, etc.

[0067] It can be understood that the first channel contention and the second channel contention are named to distinguish the two channel contentions. In practical application, the two channel contentions (i.e., the first channel contention and the second channel contention) may comply with the same channel contention mechanism. For example, both of the two channel contentions (i.e., the first channel contention and the second channel contention) comply with the CSMA / CA mechanism, or both of the two channel contentions comply with the EDCA channel contention mechanism.

[0068] In one example, FIG. 5a is a schematic diagram of a first time sequence of multilink channel access according to an embodiment of the present application. As shown in FIG. 5a, the first link is link1, and the second link is link2. The multilink device performs channel contention on two links (link1 and link2). It is assumed that the multilink device first backs off to 0 on link1. In this case, the multilink device suspends link1 and waits to perform channel contention on link2. When the backoff counter on link2 cannot back off to 0 for a long time, the multilink device stops transmitting data on link1 and link2 in parallel. Then, the multilink device may perform channel contention on link1 again, and transmit data on link1 after the backoff counter backs off to 0 in this channel contention.

[0069] Optionally, the initial value of the back-off counter in the first channel contention may be determined based on the first value of the contention window, and the initial value of the back-off counter in the second channel contention may be determined based on the second value of the contention window. Because the multilink device performs the first channel contention on the first link and does not transmit data on the first link after backing off to 0, i.e., does not perform frame exchange, the multilink device cannot determine whether the first channel contention on the first link is successful. Therefore, in the process of performing the second channel contention on the first link, the multilink device may keep the value of the contention window unchanged, in other words, the value of the CW does not increase or decrease, which means that the second value of the CW is equal to the first value. Alternatively, in the process of performing the second channel contention on the first link, the multilink device sets the value of the contention window to a minimum value, i.e., CWmin.

[0070] It can be understood that a larger contention window in the channel contention process indicates a lower contention collision probability and a longer backoff time, and a smaller contention window indicates a shorter backoff time and a higher contention collision probability. Therefore, in this embodiment of the present application, when a multi-link device backs off to 0 on a link but does not transmit on the link, it performs channel contention / channel access on the link again and sets the value of the contention window unchanged or sets the value of the contention window to the minimum value CWmin, thereby achieving a balance between the backoff time and the contention collision probability.

[0071] Optionally, after the value of the backoff counter is backed off to 0 in the first channel contention, i.e., after the backoff counter is backed off to 0 on the first link, the multilink device may detect the state of the first link in the first period. If the state of the first link in the first period is an idle state, this indicates that no collision will occur if transmission is performed on the first link. In this case, it is predicted that the transmission on the first link can be successful. Then, in the process of performing a second channel contention on the first link, the multi-link device may use the value of the contention window in the previous channel contention process on the same link (i.e., the first value) as the value of the contention window in the current channel contention process (i.e., the second value), or may set the value of the contention window in the current channel contention process (i.e., the second value) to the minimum value of the contention window, i.e., CWmin, or may set the value of the contention window in the current channel contention process (i.e., the second value) to half the value of the contention window in the previous channel contention process (i.e., the first value), where the second value is specifically the first value minus 1 divided by 2, i.e., CW=(CW-1) / 2.

[0072] If the state of the first link in the first period is busy, this indicates that a collision will occur if transmission is performed on the first link. In this case, it is predicted that the transmission on the first link will fail. Then, in the process of performing a second channel contention on the first link, the multilink device may increase the value of the contention window in the previous channel contention process on the same link (i.e., the first value) and use the increased value as the value of the contention window in the current channel contention process (i.e., the second value), in other words, the second value is greater than the first value. Specifically, the second value may be twice the first value plus 1, i.e., CW=2*CW+1. The first period may be a clear channel assessment time (CCA time), for example, 4 μs (microseconds) or 9 μs.

[0073] Optionally, after the value of the backoff counter is backed off to 0 in the first channel contention, i.e., after the backoff counter is backed off to 0 on the first link, the multilink device may receive on the first link. If the frame is received within the preset time and it is determined based on the information in the frame that the frame is transmitted by a station in the local cell, the transmission on the first link is predicted to fail. If the frame is not received within the preset time or if the frame is received within the preset time and it is determined based on the information in the frame that the frame is not transmitted by a station in the local cell, the transmission on the first link may be predicted to succeed. If the transmission on the first link is predicted to be successful, in the process of performing second channel contention on the first link, the multilink device may keep the contention window value unchanged (the second value is equal to the first value), or set the contention window value to a minimum value CWmin, or set the contention window value to half the contention window value in the process of first channel contention (the second value is equal to the first value minus 1 divided by 2), i.e., CW=(CW-1) / 2. If the transmission on the first link is predicted to be unsuccessful, in the process of performing second channel contention on the first link, the multilink device may increase the contention window value in the process of first channel contention and use the increased value as the contention window value in the process of second channel contention, in other words, the second value is greater than the first value. Specifically, the second value may be twice the first value plus 1, i.e., CW=2*CW+1.

[0074] It can be seen that in this embodiment of the present application, after the backoff counter backs off to 0 in the first channel contention, the state of the first link is determined to estimate whether the transmission on the first link is successful, and the value of the contention window is set according to the estimation result. In this way, the size of the contention window can be adjusted more accurately and appropriately, thereby further obtaining a balance between the backoff time and the contention collision probability.

[0075] Optionally, before the multilink device performs the second channel contention on the first link, the multilink device performs the channel contention on the second link and detects the state of the first link when the value of the back-off counter becomes 0 in the channel contention. If the state of the first link is busy, the multilink device does not wait for the first link and the multilink device transmits data on the second link. The multilink device performs the second channel contention on the first link after the state of the first link changes from busy to idle. The multilink device transmits data on the first link after the value of the back-off counter becomes 0 in the second channel contention.

[0076] In one example, FIG. 5b is a schematic diagram of a second time sequence of multilink channel access according to an embodiment of the present application. As shown in FIG. 5b, the first link is link1, and the second link is link2. The multilink device performs channel contention on two links (link1 and link2). It is assumed that the multilink device first backs off to 0 on link1. In this case, the multilink device suspends link1 and waits to perform channel contention on link2. If the status of link1 changes to busy in the waiting process of link1, and the status of link1 is still busy after the backoff counter on link2 backs off to 0, the multilink device stops transmitting data on link1 and link2 in parallel, i.e., assuming that the multilink device does not wait for parallel transmission on link1 and link2, the multilink device may transmit data on link2 after the backoff counter on link2 backs off to 0. After the state of link1 returns to the idle state, the multilink device may again engage in channel contention on link1, and transmit data on link1 after the backoff counter backs off to 0 in this channel contention.

[0077] In this embodiment of the present application, after the multi-link device backs off to 0 on the first link, in the process of waiting for channel contention on the second link, the state of the first link changes to a busy state, and when the multi-link device backs off to 0 on the second link, the first link is still in a busy state; in this case, it can be understood that directly transmitting data on the second link can improve channel utilization.

[0078] Optionally, before the multilink device performs second channel contention on the first link, the multilink device performs channel contention on the second link and detects the state of the first link when the value of the back-off counter becomes 0 in the channel contention. If the state of the first link is busy, the multilink device may suspend the second link, i.e., the multilink device does not transmit on the second link. The multilink device performs second channel contention on the first link when the state of the first link changes from busy to idle.

[0079] Optionally, the multilink device may detect the state of the second link when the value of the backoff counter in the second channel contention becomes 0. If the state of the second link is idle, the multilink device may transmit data on the first link and the second link in parallel.

[0080] In one example, FIG. 5c is a schematic diagram of a third time sequence of multilink channel access according to an embodiment of the present application. As shown in FIG. 5c, the first link is link1, and the second link is link2. The multilink device performs channel contention on two links (link1 and link2). It is assumed that the multilink device first backs off to 0 on link1. In this case, the multilink device suspends link1 and waits to perform channel contention on link2. If the state of link1 changes to busy in the waiting process of link1, and the state of link1 is still busy after the backoff counter on link2 backs off to 0, it is assumed that the multilink device still decides to transmit data in parallel on link1 and link2, i.e., wait for parallel transmission on link1 and link2, the multilink device may suspend link2 after the backoff counter on link2 backs off to 0. After the state of link1 returns to the idle state, the multilink device performs channel contention on link1 again, and detects the state of link2 after the backoff counter backs off to 0 in this channel contention. When the state of link2 is idle, the multilink device transmits data on link1 and link2 in parallel.

[0081] In this embodiment of the present application, after the multi-link device backs off to 0 on the first link, in the process of waiting for channel contention on the second link, the state of the first link changes to a busy state, and when the multi-link device backs off to 0 on the second link, the first link is still in a busy state; after the state of the first link returns to an idle state, the multi-link device again performs channel contention on the first link, and transmits data on the first link and the second link in parallel after backing off to 0. In this way, the peak transmission rate can be increased.

[0082] In this embodiment of the present application, the multilink device performs channel contention on the second link. After the value of the backoff counter on one link (i.e., the first link) backs off to 0, the multilink device suspends the link and waits for channel contention on the other link (i.e., the second link). If the backoff counter on the other link cannot back off to 0 for a long time, the multilink device performs channel contention on the first link again (i.e., the second channel contention). The value of the contention window in this channel contention process (i.e., the second channel contention) is equal to the value of the contention window in the previous channel contention process on the first link (i.e., the first channel contention). In other words, the value of the contention window does not change in the process of the first channel contention and the process of the second channel contention. Alternatively, the value of the contention window in this channel contention process (i.e., the second channel contention) is equal to the minimum value CWmin of the contention window. In this embodiment of the present application, when a multi-link device backs off to 0 on a link but does not transmit on that link, a balance between the backoff time and the contention collision probability can be achieved by performing channel contention / channel access on the link again and setting the contention window value unchanged or setting the contention window value to a minimum value CWmin.

[0083] In an optional embodiment, the multilink device performs a first channel contention on a first link, and suspends the first link, i.e., does not transmit on the first link, after the value of the back-off counter backs off to 0 in the first channel contention. The multilink device performs a channel contention on a second link, and detects the state of the first link after the value of the back-off counter backs off to 0 during the channel contention. If the state of the first link is idle, the multilink device transmits data on the first link and the second link in parallel.

[0084] Optionally, the method for detecting the state of the first link includes: The multilink device detects whether the state of the first link is always in an idle state in a certain period (e.g., a point coordinate function (PCF) inter frame space (PIFS)) before the value of the back-off counter backs off to 0 during channel contention on the second link. If the state of the first link is in an idle state in this period (PIFS), the multilink device determines that the state of the first link is in an idle state. It can be understood that the state of the second link can also be detected according to this method in the same way. Details will not be described again here.

[0085] In one example, Figure 5d is a schematic diagram of a fourth time sequence of multilink channel access according to an embodiment of the present application. As shown in Figure 5d, the first link is link1, and the second link is link2. The multilink device performs channel contention on two links (link1 and link2). It is assumed that the multilink device first backs off to 0 on link1. In this case, the multilink device suspends link1 and waits to perform channel contention on link2. If the state of link1 changes to busy once in the backoff process of link2, and the state of link1 has already returned to idle when the backoff counter on link2 backs off to 0, the multilink device transmits data on link1 and link2 in parallel.

[0086] In another optional embodiment, the channel access method for a multi-link device provided in the present application may also be applied to a single-link multi-channel access scenario. FIG. 6 is a schematic diagram of a single-link multi-channel according to an embodiment of the present application. As shown in FIG. 6, a single link may include N channels, where channel 1, channel 5, ..., and channel N-3 are configured as channels used for channel access. The first link and the second link may correspond to the first channel (e.g., channel 1) and the second channel (e.g., channel 5) in the single-link multi-channel access scenario. Specifically, the communication device performs a first channel contention on the first channel, and an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window, and when the value of the back-off counter in the first channel contention becomes 0 and the communication device does not transmit data on the first channel, the communication device performs a second channel contention on the first channel, and an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window. The second value of the contention window is equal to the first value of the contention window, or the second value of the contention window is equal to the minimum value of the contention window.

[0087] After the value of the back-off counter becomes 0 in the first channel contention, the communication device suspends the first link, i.e., does not transmit data on the first channel, and waits for channel contention on the second channel. When the time that the first channel waits for channel contention on the second channel exceeds the preset time, the state of the second channel is still busy, indicating that the back-off counter on the second channel cannot back off to 0 for a long time. In this case, the multi-channel device performs channel contention again on the first channel, i.e., the multi-channel device performs second channel contention on the first channel. Alternatively, after the value of the back-off counter becomes 0 in the first channel contention, the multi-channel device receives a data packet on the second channel, and the length of the data packet exceeds the preset time. This indicates that a relatively long network allocation vector is set on the second channel. In this case, the multi-channel device performs channel contention again on the first channel, i.e., the multi-channel device performs second channel contention on the first channel.

[0088] In yet another optional embodiment, if the multilink device determines that all potential receiving stations (i.e., receivers of buffered data) on a link are of non-STR MLD sequence and all potential receiving stations are unable to receive due to inter-link interference, the multilink device may suspend channel contention on the link, i.e., stop backing off or not transmit if the multilink device backs off to 0 on the link. When one or more potential receiving stations on the link are able to receive, the multilink device re-contents the channel on the link. The contention window value used when the multilink device re-contents the channel on the link is the same as the contention window value the multilink device last time it contentions the channel on the link. Alternatively, the contention window value used when the multilink device re-contents the channel on the link is a minimum value, i.e., CWmin.

[0089] The above describes in detail the method provided in the present application. In order to better implement the aforementioned solutions in the embodiments of the present application, the embodiments of the present application further provide a corresponding apparatus or device.

[0090] In the embodiment of the present application, the multi-link device may be divided into functional modules based on the method example. For example, each functional module may be obtained by division based on each corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software function module. It should be noted that in the embodiment of the present application, the division into modules is an example, and is merely a logical functional division, and may be other divisions in actual implementation.

[0091] When an integrated unit is used, FIG. 7 is a schematic diagram of the structure of a communication device according to an embodiment of the present application. The communication device 1 may be a multi-link device or a chip such as a Wi-Fi chip in a multi-link device. As shown in FIG. 7, the communication device 1 includes a processing unit 11.

[0092] The processing unit 11 is configured to perform a first channel contention on the first link, and an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window. The processing unit is further configured to perform a second channel contention on the first link when the value of the back-off counter in the first channel contention becomes 0 and the multi-link device does not transmit on the first link. An initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window. The second value of the contention window is equal to the first value of the contention window, or the second value of the contention window is equal to a minimum value of the contention window.

[0093] Optionally, the multi-link device not transmitting on the first link includes a state of the second link being busy when the time the first link waits for channel contention on the second link exceeds a preset time.

[0094] Optionally, the multilink device not transmitting on the first link includes a length of a data packet received by the multilink device on the second link exceeding a preset time after a value of a backoff counter becomes zero in the first channel contention.

[0095] Optionally, simultaneous transmit and receive STRs are not supported between the first link and the second link.

[0096] Optionally, the processing unit 11 is further configured to detect a state of the first link in a first period, and when the state of the first link in the first period is an idle state, determine the first value of the contention window as the second value, or determine the second value of the contention window as a minimum value of the contention window.

[0097] Optionally, the processing unit 11 is further configured to: perform channel contention on the second link, detect the state of the first link when the value of the back-off counter becomes 0 in the channel contention, and suspend the second link when the state of the first link is busy. The processing unit 11 is configured to perform second channel contention on the first link when the state of the first link changes from busy to idle.

[0098] Optionally, the communication device further includes a transceiver unit 12. The processing unit 11 is further configured to detect, for a multi-link device, a state of a second link when a value of a back-off counter becomes 0 in a second channel contention. The transceiver unit 12 is configured to transmit data in parallel on the first link and the second link when a state of the second link is an idle state.

[0099] Optionally, the processing unit 11 is further configured to perform channel contention on the second link, and detect the state of the first link when the value of the back-off counter in the channel contention becomes 0. The transceiver unit 12 is configured to transmit data on the second link when the state of the first link is busy.

[0100] The communication device 1 in this embodiment of the present application has any function of the multi-link device in the above-mentioned method, and the details will not be described again here.

[0101] The above describes the multi-link device in the embodiment of the present application, and the following describes possible product forms of the multi-link device. It should be understood that any form of product having the function of the multi-link device in FIG. 7 falls within the scope of protection of the embodiment of the present application. It should be further understood that the following description is merely an example, and the product form of the multi-link device in the embodiment of the present application is not limited thereto.

[0102] In one possible product form, the multi-link device in the embodiments of the present application may be implemented using a common bus architecture.

[0103] The multilink device includes a processor, the processor is configured to: perform a first channel contention on a first link, an initial value of a back-off counter in the first channel contention being determined based on a first value of a contention window, and when a value of the back-off counter in the first channel contention becomes zero and the multilink device does not transmit on the first link, perform a second channel contention on the first link, an initial value of the back-off counter in the second channel contention being determined based on a second value of the contention window, the second value of the contention window being equal to the first value of the contention window or the second value of the contention window being equal to a minimum value of the contention window.

[0104] Optionally, the multilink device may further include a memory, the memory configured to store instructions executed by the processor. Optionally, the multilink device may further include a transceiver internally connected to the processor and in communication with the processor. The transceiver is configured to support communication between the multilink device and another device, for example, to transmit data in parallel on the first link and the second link when the state of the second link is idle, or to transmit data on the second link when the state of the first link is busy.

[0105] In one possible product form, the Multi-Link device in the embodiments of the present application may be implemented using a general-purpose processor.

[0106] A general-purpose processor for implementing a multi-link device includes a processing circuit configured to: perform a first channel contention on a first link, where an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window, and when a value of the back-off counter in the first channel contention becomes zero and the multi-link device does not transmit on the first link, perform a second channel contention on the first link, where an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window, where the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window.

[0107] Optionally, the general-purpose processor may further include a storage medium, the storage medium configured to store instructions to be executed by the processing circuit. Optionally, the general-purpose processor may further include an input / output interface internally connected to the processing circuit and in communication with the processing circuit. The input / output interface is configured to support communication between the general-purpose processor and another device, for example, to transmit data in parallel on the first link and on the second link when the state of the second link is idle, or to transmit data on the second link when the state of the first link is busy.

[0108] In one possible product form, the multi-link devices in the embodiments of this application may alternatively be implemented using one or more FPGAs (field programmable gate arrays), PLDs (programmable logic devices), controllers, state machines, gate logic, discrete hardware components, any other suitable circuitry, or any combination of circuitry capable of performing the various functions described throughout this application.

[0109] It should be understood that the communication devices in the various product forms described above have any functions of the multi-link device in the method embodiments described above, and the details will not be described again here.

[0110] An embodiment of the present application further provides a computer-readable storage medium, which stores computer program code, which, when executed by the processor, causes the electronic device to perform the method in the embodiment.

[0111] An embodiment of the present application further provides a computer program product, which when run on a computer, enables the computer to perform the method in the aforementioned embodiment.

[0112] An embodiment of the present application further provides a communication device. The device may exist in the form of a chip product. The structure of the device includes a processor and an interface circuit. The processor is configured to communicate with another device using the interface circuit, so that the device performs the method in the above embodiment.

[0113] The method or algorithm steps described in conjunction with the contents disclosed in this application may be implemented by hardware or by a processor executing software instructions. The software instructions may include corresponding software modules. The software modules may be stored in a Random Access Memory (RAM), a flash memory, an Erasable Programmable Read Only Memory (EPROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a register, a hard disk, a removable hard disk, a Compact Disk Read Only Memory (CD-ROM), or any other form of storage medium known in the art. For example, the storage medium is connected to the processor so that the processor can read information from the storage medium or write information to the storage medium. Of course, the storage medium may alternatively be components of the processor. The processor and the storage medium may be located in an ASIC. In addition, the ASIC may be located in the core network interface device. Of course, the processor and the storage medium may alternatively be present as discrete components in the core network interface device.

[0114] In one or more of the foregoing examples, those skilled in the art should recognize that the functions described in this application may be implemented using hardware, software, firmware, or any combination thereof. If software is used to implement the functions, the functions may be stored on or transmitted as one or more instructions or codes in a computer-readable medium. Computer-readable media include computer-readable storage media and communication media. Communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media may be any available medium accessible to a general-purpose or special-purpose computer.

[0115] The objectives, technical solutions and advantages of the present application are further described in detail in the above specific implementation forms. It should be understood that the above description is merely a specific implementation form of the present application, and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements or improvements made based on the technical solutions of the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims. [Explanation of symbols]

[0116] 1. Communications equipment 11 Processing Unit 12 Transceiver unit

Claims

1. 1. A channel access method for a multilink device, comprising: performing a first channel contention on a first link by the multilink device, wherein an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window; performing a second channel contention on the first link by the multilink device when the value of the backoff counter becomes 0 in the first channel contention and the multilink device does not transmit on the first link, wherein an initial value of the backoff counter in the second channel contention is determined based on a second value of the contention window, and the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window; A method comprising:

2. 2. The method of claim 1, wherein the multilink device not transmitting on the first link comprises a state of the second link being busy when the first link waits for channel contention on a second link for more than a preset time.

3. 2. The method of claim 1, wherein the multilink device not transmitting on the first link comprises a length of a data packet received by the multilink device on a second link exceeding a preset time after the value of the backoff counter becomes zero in the first channel contention.

4. 4. The method of claim 2 or 3, wherein simultaneous transmit and receive STR is not supported between the first link and the second link.

5. Prior to the step of conducting second channel contention on the first link by the multilink device, the method further comprises: detecting, by the multilink device, a state of the first link during a first period; if the state of the first link during the first time period is an idle state, determining, by the multilink device, the first value of the contention window as the second value or determining the second value of the contention window as the minimum value of the contention window; 5. The method of claim 1, further comprising:

6. Prior to the step of conducting second channel contention on the first link by the multilink device, the method further comprises: performing channel contention on a second link by the multilink device, and detecting a state of the first link when a value of the backoff counter becomes zero during the channel contention; suspending, by the multilink device, the second link if the state of the first link is busy; triggering the multilink device to conduct contention for the second channel on the first link when the state of the first link changes from the busy state to an idle state; 6. The method of claim 1, further comprising:

7. After the step of conducting a second channel contention on the first link by the multilink device, the method further comprises: detecting a state of the second link by the multilink device when the value of the backoff counter becomes 0 in the second channel contention; transmitting data in parallel over the first link and the second link by the multilink device when the state of the second link is an idle state; 7. The method of claim 6, further comprising:

8. Prior to the step of conducting second channel contention on the first link by the multilink device, the method further comprises: performing channel contention on a second link by the multilink device, and detecting a state of the first link when a value of the backoff counter becomes zero during the channel contention; transmitting data on the second link by the multilink device if the state of the first link is busy; 6. The method of claim 1, further comprising:

9. A communication apparatus applied to a multi-link device, A processing unit configured to perform a first channel contention on a first link, and an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window; the processing unit is further configured to: perform a second channel contention on the first link when a value of the backoff counter becomes 0 in the first channel contention and the multilink device does not transmit on the first link; and an initial value of the backoff counter in the second channel contention is determined based on a second value of the contention window, and the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window.

10. 10. The communication apparatus of claim 9, wherein the multilink device not transmitting on the first link comprises a state of the second link being busy when the time the first link waits for channel contention on a second link exceeds a preset time.

11. 10. The communication device of claim 9, wherein the multilink device not transmitting on the first link comprises a length of a data packet received by the multilink device on a second link exceeding a preset time after the value of the backoff counter becomes zero in the first channel contention.

12. 12. The communication device of claim 10 or 11, wherein simultaneous transmit and receive STR is not supported between the first link and the second link.

13. The processing unit includes: Detecting a state of the first link during a first time period; determining the first value of the contention window as the second value or determining the second value of the contention window as the minimum value of the contention window when the state of the first link during the first time period is an idle state; 13. The communication device of claim 9, further configured to:

14. The processing unit includes: performing channel contention on a second link, and detecting a state of the first link when a value of the backoff counter becomes 0 during the channel contention; Suspending the second link when the state of the first link is busy. The method further comprises:

14. The communication device of claim 9, wherein the processing unit is configured to perform the second channel contention on the first link when the state of the first link changes from the busy state to an idle state.

15. The processing unit is further configured to detect, for the multilink device, a state of the second link when a value of the back-off counter becomes 0 in the second channel contention; 15. The communication device of claim 14, further comprising a transceiver unit configured to transmit data in parallel on the first link and on the second link when the state of the second link is idle.

16. The processing unit is further configured to perform channel contention on a second link, and detect a state of the first link when a value of the back-off counter becomes zero during the channel contention; 14. The communication device of claim 9, further comprising a transceiver unit configured to transmit data on the second link when the state of the first link is busy.

17. 1. A communications device comprising: a processor, the processor comprising: performing a first channel contention on a first link, wherein an initial value of a back-off counter in the first channel contention is determined based on a first value of a contention window; When the value of the back-off counter becomes 0 in the first channel contention and the multilink device does not transmit on the first link, a second channel contention is performed on the first link, and an initial value of the back-off counter in the second channel contention is determined based on a second value of the contention window, and the second value of the contention window is equal to the first value of the contention window or the second value of the contention window is equal to a minimum value of the contention window; A communication device configured to:

18. 9. A computer readable storage medium having instructions stored thereon that, when executed on a computer, enable the computer to perform the method of any one of claims 1 to 8.

19. A computer program product comprising instructions which, when executed on a computer, enable the computer to perform the method according to any one of claims 1 to 8.

20. A chip or chip system comprising a processing circuit, the processing circuit being configured to perform the method according to any one of claims 1 to 8.

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