Channel access method for multi-link devices and related apparatus

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 Administration 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 technology, 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, such as simultaneous communication in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands, or simultaneous communication in different channels of the same frequency band. Such wireless communication devices are usually called multi-link devices (MLDs). It is clear that multi-link devices can significantly increase transmission speeds because they can perform parallel communication over multiple links.

[0004] Multilink devices can increase transmission speeds by communicating in parallel over multiple links. However, 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 properly demodulate data packets that need to be received on another link. In other words, multilink devices do not support simultaneous transmit and receive (STR) on multiple links. Therefore, for non-STR multilink devices, channel contention occurs on two links. When a transmission occurs on one link whose backoff counter reaches zero, the energy transmitted on that link leaks onto the other link. 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, 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, the multilink device may wait for channel contention on the other link instead of transmitting data, so that channel contention on the other link can proceed normally. However, since the multilink device performs channel contention on a link and does not transmit data after backing off to 0, how the multilink device can access the channel again on the link becomes an urgent problem to be solved. Summary of the Invention [Means for solving the problem]

[0006] Embodiments of the present application provide 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 backoff time and contention collision probability.

[0007] The following describes the present application from various aspects. It should be understood that cross-references may be made between the following implementations 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 multilink device. The method includes: the multilink device performs first channel contention on a first link; when a backoff counter value becomes 0 during the first channel contention and the multilink device does not transmit on the first link, the multilink device may perform second channel contention on the first link; an initial value of the backoff counter during the first channel contention is determined based on a first value of a contention window, and an initial value of the backoff counter during 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 the minimum value of the contention window.

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

[0010] Optionally, the reasons why the multilink device does not transmit on the first link include: After the value of the backoff counter in the first channel contention becomes 0, the multilink device suspends 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 backoff counter on the second link cannot back off to 0 for a long time; 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.

[0011] Optionally, the reason why the multilink device does not transmit on the first link includes the following: After the value of the backoff 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 the preset time. This 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 leaves the contention window value unchanged or sets the contention window value to the minimum value CWmin, thereby achieving a balance between backoff time and 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 during a first time period; if the state of the first link during the first time period is idle, the multilink device uses a first value of the contention window during the first channel contention as a second value of the contention window during 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 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 achieving a balance between the backoff time and the contention collision probability.

[0016] 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 engages in channel contention on the second link and detects the state of the first link when the value of a backoff counter becomes 0 during 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 does the multilink device engage in second channel contention on the first link.

[0017] Optionally, the multi-link device detects the state of the second link when the value of the back-off counter becomes 0 in the second channel contention, and the multi-link 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 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. When the multilink device backs off to 0 on the second link, the first link is still in busy state. After the state of the first link returns to idle, the multilink device again performs channel contention on the first link, backs off to 0, and then transmits data on the first link and the second link in parallel. In this way, the peak transmission rate can be increased.

[0019] 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 engages in channel contention on the second link and detects the state of the first link when the value of the backoff counter becomes 0 during the channel contention; and the multilink device may transmit data on the second link if the state of the first link is busy.

[0020] Optionally, the multilink device engages in second channel contention on the first link only when the 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 the value of the back-off counter becomes 0 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 busy, in this case, the multilink device can directly transmit data on the second link, thus improving channel utilization.

[0022] According to a second aspect, an embodiment of the present application provides a communication device, which may be a multi-link device or a chip such as a Wi-Fi chip within the multi-link device, The multilink device includes a processing unit configured to perform first channel contention on a first link, and an initial value of a backoff 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 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 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.

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

[0024] Regarding the second aspect, in one possible design, the multilink device not transmitting on the first link includes the length of a data packet received by the multilink device on the second link exceeding a preset time after the value of a backoff counter 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: conduct channel contention on the second link; detect the state of the first link when the value of the backoff counter becomes 0 during channel contention; and suspend the second link when the state of the first link is busy. The processing unit is configured to conduct 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 communications apparatus further includes a transceiver unit, wherein the processing unit is further configured to detect a state of a second link when a value of a backoff counter becomes 0 in a second channel contention for a multilink device, and 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 idle.

[0029] Regarding the second aspect, in one possible design, the communications device further includes a transceiver unit, wherein the processing unit is further configured to perform channel contention on the second link and detect the state of the first link when a value of a backoff counter becomes 0 during the channel contention, and the transceiver unit is configured to transmit data on the second link when the 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 first channel contention on a first link, wherein an initial value of a backoff counter in the first channel contention is determined based on a first value of a contention window; and, when the value of the backoff counter in the first channel contention becomes 0 and the multi-link device does not transmit on the first link, perform second channel contention 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, 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 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 first channel contention on a first link, wherein an initial value of a backoff counter for the first channel contention is determined based on a first value of a contention window; and, when the value of the backoff counter for the first channel contention becomes 0 and the multi-link device does not transmit on the first link, perform second channel contention on the first link, wherein an initial value of the backoff counter for 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.

[0034] According to a fifth aspect, the present application provides a computer-readable storage medium having stored thereon instructions 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 including instructions 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.

[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, 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 backoff time and contention collision probability.

[0037] 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 explanation 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; [Figure 2] 1 is a schematic diagram of the architecture of a wireless communication system according to an embodiment of the present application; [Figure 3a] 1 is a schematic diagram of the structure of a multi-link device according to an embodiment of the present application; [Figure 3b] FIG. 10 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. 10 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. 10 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 INVENTION

[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 embodiments 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 embodiments of the present application. It can be understood that the system architecture and / or scenario described in the embodiments of the present application are intended to more clearly describe the technical solutions in the embodiments of the present application, and do not constitute limitations on the technical solutions provided in the embodiments of the present application.

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

[0042] A multilink device includes one or more affiliated stations (STAs). An affiliated station is a logical station that 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 explanation, in this application, a multilink device whose affiliated station is an AP will be referred to as a multilink AP, multilink AP device, or AP multilink device (AP MLD), and a multilink device whose affiliated station is a non-AP STA will be referred to as a multilink non-AP, multilink non-AP device, or Non-AP multilink device (Non-AP MLD).

[0043] Optionally, one multi-link device may include multiple logical stations, each operating on one link, although multiple logical stations are allowed 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 the 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 another device.

[0046] The channel access method for a multi-link device provided in an embodiment of the present application may be applied to a wireless local area network (WLAN). FIG. 2 is a schematic diagram of the architecture of a wireless communication system according to an embodiment of the present application. As shown in FIG. 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 may communicate with each other over multiple links. One AP in the AP MLD may 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 FIG. 2 are merely examples.

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

[0048] It can be understood that a multilink device may support high-speed, low-latency transmission. With the continuous evolution of application scenarios for wireless local area networks, multilink devices may be further applied to more scenarios, such as sensor nodes in smart cities (e.g., smart water meters, smart electricity meters, and smart air detection nodes), smart devices in smart homes (e.g., smart cameras, projectors, displays, televisions, stereos, refrigerators, and 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, and some infrastructure in everyday 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 multilink device is not limited in the embodiments of this application, and the description herein is merely an example. The 802.11 protocol may support 802.11be or be 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) and media access control (MAC) layer parts of 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. Naturally, 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 embodiments of the present application. 3a and 3b are merely examples for explanation. For example, the high MAC layer and 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 multilink device in the embodiment of the present application may be a single-antenna device or a multi-antenna device, for example, a device having three or more antennas. The number of antennas included in the multilink device is not limited in the embodiment of the present application. In the embodiment of the present application, the multilink 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 multilink device referred to in the embodiments of the present application does not support STR on two links. It can be understood that "supporting STR" in the present application may mean that the device has STR capability and uses the STR capability in the current communication, and "not supporting 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 multilink device may switch between STR and non-STR, i.e., may switch from supporting STR to not supporting STR, or may switch 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 first channel contention on the 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 the second link. It can be understood that "suspend" in this application may be understood as "not performing transmission," and that "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. 802.11 uses the CSMA / CA mechanism to ensure that access points and stations can access the wireless medium without colliding with each other. This mechanism is also called a distributed coordination function (DCF). The CSMA / CA mechanism is specifically as follows: Before transmitting data, a station needs to perform clear channel access (CCA) on the wireless medium. If the wireless medium is idle for a certain period of time (e.g., a distributed inter-frame space (DIFS)), the station may initiate a random backoff process. If the wireless medium is busy during that period of time, the station needs to wait until the wireless medium becomes idle and then remains idle for a certain period of time (e.g., a DIFS) before initiating the random backoff process. After the random backoff process is completed, the station may exchange frames. 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 uniformly 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, a contention window (CW) has multiple values, and when a station makes an initial attempt to contention for the channel, 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 continuously increases 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, allowing 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 for different access categories are listed in Table 1, where AC_VO indicates the access category is a voice flow, AC_VI indicates the access category is a video flow, AC_BE indicates the access category is a best effort flow, and AC_BK indicates the access category is a background flow.

[0061] [Table 1]

[0062] The random backoff process for 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, it must remain idle for an AIFS before the random backoff process can take place. The AIFS calculation method can be obtained by taking the sum of the short inter-frame space (SIFS) and the product of the adjusted inter-frame space number (AIFSN) and a slot time (a Slot Time), i.e., 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 first channel contention may be CSMA / CA or EDCA. The initial value of the backoff counter in the first channel contention may be determined based on the first value of the contention window. During the channel contention process, the value of the backoff counter decreases from the initial value until the value of the backoff counter reaches 0. It may be understood that if the multilink device attempts channel contention on the first link for the first time, the first value may be CWmin. If the multilink 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 if transmission fails, and the value of CW is set to CWmin if transmission is successful.

[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 second channel contention on the first link, and the initial value of the backoff counter in the second channel contention is determined based on the 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 the minimum value of the contention window.

[0065] Specifically, after the backoff counter value in the first channel contention is backed off to 0, if the backoff counter on the second link has 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. If the second link is still busy when the time the first link waits for channel contention on the second link exceeds a preset time, this indicates that the second link has been busy for a long time, and the multilink device may stop transmitting parallel 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 is backed off to 0 in the second channel contention. Alternatively, if the length of the 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 reaches 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 cease parallel transmission on the first and second links. In this case, the multilink device may conduct 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 and second links, i.e., is non-STR.

[0066] It can be understood that "data transmission" and "transmitting data" 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 applications, 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 the two channel contentions (i.e., the first channel contention and the second channel contention) comply with the CSMA / CA mechanism, or both the two channel contentions comply with the EDCA channel contention mechanism.

[0068] In one example, Figure 5a is a schematic diagram of a first time sequence of multilink channel access according to one embodiment of the present application. As shown in Figure 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 initially 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 period of time, the multilink device stops transmitting data on link1 and link2 in parallel. The multilink device may then 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 backoff counter for the first channel contention may be determined based on the first value of the contention window, and the initial value of the backoff counter for the second channel contention may be determined based on the second value of the contention window. Because the multilink device performs 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 will be successful. Therefore, in the process of performing 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 CW is neither increased nor decreased, which means that the second value of CW is equal to the first value. Alternatively, in the process of performing 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 contention window value unchanged or sets the contention window value 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 idle, this indicates that no collision will occur if transmission is performed on the first link. In this case, it is predicted that transmission on the first link can be successful. Then, in the process of performing 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 of 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 during the first period is busy, this indicates that a collision will occur if transmission is performed on the first link. In this case, the transmission on the first link is predicted to 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 a frame is received within a preset time and it is determined based on 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 a frame is not received within the preset time, or if a frame is received within the preset time and it is determined based on 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 either keep the contention window value unchanged (the second value is equal to the first value), or set the contention window value to the 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 may be 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 understood 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 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 achieving a balance between the backoff time and the contention collision probability.

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

[0076] In one example, Figure 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 Figure 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 during 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 in parallel on link1 and link2. That is, assuming that the multilink device does not wait for parallel transmission on link1 and link2, the multilink device can 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 multi-link 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 engages in second channel contention on the first link, the multilink device engages in channel contention on the second link and detects the state of the first link when the value of a backoff counter becomes 0 during 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 engages in 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, Figure 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 Figure 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 status of link1 changes to busy during 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 still determines to transmit data on link1 and link2 in parallel, 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 again engages in channel contention on link1, and detects the state of link2 after the backoff counter backs off to 0 during this channel contention. If 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 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 a busy state. When the multilink 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 multilink device again performs channel contention on the first link, and after backing off to 0, transmits data on the first link and the second link in parallel. In this way, the peak transmission rate can be increased.

[0082] In this embodiment of the present application, a multilink device performs channel contention on a 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 that 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 period of 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 between the first channel contention process and the second channel contention process. 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, 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 the minimum value CWmin, thereby achieving a balance between backoff time and contention collision probability.

[0083] In one 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 a backoff counter backs off to 0 during 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 a backoff 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 a backoff 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. 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 status of link1 changes to busy once during the backoff process of link2, and the status of link1 has already returned to idle when the backoff counter on link2 backs off to 0, the multilink device will transmit 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 access scenario according to one 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, a communication device performs first channel contention on the first channel, and an initial value of a backoff counter in the first channel contention is determined based on a first value of a contention window. If the value of the backoff counter in the first channel contention becomes 0 and the communication device does not transmit data on the first channel, the communication device performs second channel contention on the first channel, and an initial value of the backoff 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 backoff counter value reaches 0 during 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 during which the first channel waits for channel contention on the second channel exceeds a preset time, the state of the second channel is still busy, indicating that the backoff counter on the second channel cannot back off to 0 for a long period of time. In this case, the multi-channel device resumes channel contention on the first channel, i.e., the multi-channel device resumes second channel contention on the first channel. Alternatively, after the backoff counter value reaches 0 during 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 resumes channel contention on the first channel, i.e., the multi-channel device resumes 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 non-STR MLD aligned 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 resumes channel contention on the link. The contention window value used when the multilink device resumes channel contention on the link is the same as the contention window value the multilink device last used when it resumed channel contention on the link. Alternatively, the contention window value used when the multilink device resumes channel contention 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 corresponding apparatuses or devices.

[0090] In the embodiments of the present application, the multi-link device may be divided into functional modules based on the exemplary method. For example, each functional module may be obtained by dividing the functional modules based on the corresponding functions, 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 functional module. It should be noted that the division into modules in the embodiments of the present application is merely an example and is merely a logical division of functions, and other divisions may be used in actual implementation.

[0091] When an integrated unit is used, Figure 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 within the multi-link device. As shown in Figure 7, the communication device 1 includes a processing unit 11.

[0092] The processing unit 11 is configured to perform first channel contention on the first link, and an initial value of a backoff 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 second channel contention on the first link when the value of the backoff counter in the first channel contention becomes 0 and the multilink device does not transmit on the first link. The initial value of the backoff 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.

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

[0094] Optionally, the multi-link device not transmitting on the first link includes a length of a data packet received by the multi-link device on the second link exceeding a preset time after a value of a back-off counter becomes 0 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 a value of a 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 apparatus further includes a transceiver unit 12. For a multi-link device, the processing unit 11 is further configured to detect 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 idle.

[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 of 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 forms of the multi-link device in the embodiment of the present application are 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 configured to: perform first channel contention on a first link, wherein an initial value of a backoff counter in the first channel contention is determined based on a first value of a contention window; and, when the value of the backoff counter in the first channel contention becomes 0 and the multilink device does not transmit on the first link, perform second channel contention 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, 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.

[0104] Optionally, the multilink device may further include a memory configured to store instructions executed by the processor. Optionally, the multilink device may further include a transceiver internally connected to the processor and communicating 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: conduct first channel contention on a first link, wherein an initial value of a backoff counter for the first channel contention is determined based on a first value of a contention window; and, when the value of the backoff counter becomes zero during the first channel contention and the multi-link device does not transmit on the first link, conduct second channel contention on the first link, wherein an initial value of the backoff counter for 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.

[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 and communicating 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 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 of the 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, which may be in the form of a chip product, and the structure of the device includes a processor and an interface circuit, and 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 connection with the contents disclosed herein 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 random access memory (RAM), flash memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, 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 may be connected to the processor so that the processor can read information from 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 reside as discrete components in the core network interface device.

[0114] In one or more of the foregoing examples, those skilled in the art will recognize that the functions described herein 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 code 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 fall within 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 multi-link device, the multi-link device not supporting simultaneous transmission and reception (STR) on two links, the method comprising: performing, by the multi-link device, first channel contention on a first link of the two links, 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 backoff counter becomes 0 in the first channel contention and the multilink device does not transmit on the first link, performing second channel contention on the first link by the multilink device, 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; A method comprising:

2. The method described in claim 1, wherein the multilink device is a non-access point multilink device (non-AP MLD).

3. 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 of the two links by the multi-link device, and detecting the state of the first link when the back-off counter value becomes 0 during the channel contention; If the state of the first link is busy, suspending the second link by the multi-link device; 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; The method of claim 1 further comprising:

4. After the step of conducting second channel contention on the first link by the multilink device, the method further comprises: detecting, by the multi-link device, the state of the second link when the value of the back-off counter becomes 0 in the second channel contention; transmitting data in parallel over the first link and the second link by the multi-link device when the state of the second link is idle; 4. The method of claim 3, further comprising:

5. An apparatus, the apparatus not supporting simultaneous transmission and reception (STR) on two links, the apparatus comprising: a processor; and a memory configured to store instructions that, when executed by the processor, cause the apparatus to: conducting a first channel contention on a first link of the two links, 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 device does not transmit on the first link, a second channel contention is performed 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, and the second value of the contention window is equal to the first value of the contention window; A device that performs the following.

6. The device described in claim 5, wherein the device is a non-access point multilink device (non-AP MLD).

7. The instructions, when executed by the processor, cause the device to: performing channel contention on a second link of the two links, and detecting the state of the first link when the value of the backoff counter becomes 0 during the channel contention; If the state of the first link is busy, suspending the second link; triggering the device to conduct the second channel contention on the first link when the state of the first link changes from the busy state to an idle state; The apparatus of claim 6, further comprising:

8. The instructions, when executed by the processor, cause the device to: Detecting the state of the second link when the value of the backoff counter becomes 0 during the second channel contention; transmitting data in parallel on the first link and the second link when the state of the second link is idle; The apparatus of claim 7, further comprising:

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